WorldWideScience

Sample records for heavy gas releases

  1. Experimental and theoretical investigations on the release and propagation of heavy gas; Experimentelle und theoretische Untersuchungen zur Schwergasfreisetzung und -ausbreitung

    Energy Technology Data Exchange (ETDEWEB)

    Rauchegger, Christian

    2013-06-01

    The hazardous potential of accidental heavy gas releases, especially those involving flammable and toxic gases, is widely known. In order to predict the area in which these gases are in hazardous concentrations, an estimation of the dispersion of these gases must be carried out. While the hazardous area for flammable heavy gases is determined by the lower explosion limit (ca. > 1 vol.%), the release of toxic heavy gases can result in a much larger hazardous area, as toxic gases, even in very low concentrations (ca. < 3000 ppm), have the potential to be highly damaging. The VDI guideline 3783, which is considered as state-of-the-art in Germany, can be used to estimate the dispersion of heavy gases. However, VDI 3783 gives no method for the prediction of the height and width of a heavy gas cloud, which are both required for quantitative risk analysis as well as for a possible coupling of a Lagrangian particle model with the VDI 3783 heavy gas dispersion model. Therefore, further calculation methods were used to describe these dimensions and were evaluated against, experimental studies of the length, width and height of the heavy and neutral gas field. The influence of the source height on the heavy gas dispersion was also investigated. It was found that elevating the source leads to a reduction of the length of the heavy gas area. Once the source reaches a critical height, a heavy gas area at ground level no longer exists. Therefore, for release heights above the critical height, heavy gas dispersion effects can be neglected and the calculation of the heavy gas area according to VDI 3783 part 2 is therefore no longer necessary. The release of heavy gases can occur from a process plant as well as from a standard gas bottle. For the release of heavy gases from standard gas bottles, a mathematical model has been developed to predict the time-dependent mass flow. This model takes into account the time-dependent temperature distribution of the bottle wall, and contains a

  2. Heavy gas valves

    Energy Technology Data Exchange (ETDEWEB)

    Steier, L [Vereinigte Armaturen Gesellschaft m.b.H., Mannheim (Germany, F.R.)

    1979-01-01

    Heavy gas valves must comply with special requirements. Apart from absolute safety in operation there are stringent requirements for material, sealing and ease of operation even in the most difficult conditions. Ball valves and single plate pipe gate valves lateral sealing rings have a dual, double sided sealing effect according to the GROVE sealing system. Single plate gate valves with lateral protective plates are suitable preferably for highly contaminated media. Soft sealing gate valves made of cast iron are used for low pressure applications.

  3. Modelling isothermal fission gas release

    International Nuclear Information System (INIS)

    Uffelen, P. van

    2002-01-01

    The present paper presents a new fission gas release model consisting of two coupled modules. The first module treats the behaviour of the fission gas atoms in spherical grains with a distribution of grain sizes. This module considers single atom diffusion, trapping and fission induced re-solution of gas atoms associated with intragranular bubbles, and re-solution from the grain boundary into a few layers adjacent to the grain face. The second module considers the transport of the fission gas atoms along the grain boundaries. Four mechanisms are incorporated: diffusion controlled precipitation of gas atoms into bubbles, grain boundary bubble sweeping, re-solution of gas atoms into the adjacent grains and gas flow through open porosity when grain boundary bubbles are interconnected. The interconnection of the intergranular bubbles is affected both by the fraction of the grain face occupied by the cavities and by the balance between the bubble internal pressure and the hydrostatic pressure surrounding the bubbles. The model is under validation. In a first step, some numerical routines have been tested by means of analytic solutions. In a second step, the fission gas release model has been coupled with the FTEMP2 code of the Halden Reactor Project for the temperature distribution in the pellets. A parametric study of some steady-state irradiations and one power ramp have been simulated successfully. In particular, the Halden threshold for fission gas release and two simplified FUMEX cases have been computed and are summarised. (author)

  4. Analysis of hydrogen sulfide releases in heavy water production facilities

    International Nuclear Information System (INIS)

    Croitoru, Cornelia; Dumitrescu, Maria; Preda, Irina; Lazar, Roxana

    1996-01-01

    Safety analyses conducted at ICIS concern primarily the heavy water production installations. The quantitative risk assessment needs the frequency calculation of accident sequences and consequences. In heavy water plants which obtain primary isotopic concentration of water by H 2 O - H 2 S exchange, large amounts of hydrogen sulfide which is a toxic, inflammable and explosive gas, are circulated. The first stage in calculating the consequences consists in potential analysis of H 2 S release. This work presents a study of this types of releases for pilot installations of the heavy water production at ICIS (Plant 'G' at Rm. Valcea). The installations which contain and maneuver large quantities of H 2 S and the mathematical models for different types of releases are presented. The accidents analyzed are: catastrophic column, container, spy-hole failures or gas-duct rupture and wall cracks in the installation. The main results are given as tables while the time variations of the flow rate and quantities of H 2 O released by stack disposal are plotted

  5. Fission gas release behaviour in MOX fuels

    International Nuclear Information System (INIS)

    Viswanathan, U.K.; Anantharaman, S.; Sahoo, K.C.

    2002-01-01

    As a part of plutonium recycling programme MOX (U,Pu)O 2 fuels will be used in Indian boiling water reactors (BWR) and pressurised heavy water reactors (PHWR). Based on successful test irradiation of MOX fuel in CIRUS reactor, 10 MOX fuel assemblies have been loaded in the BWR of Tarapur Atomic Power Station (TAPS). Some of these MOX fuel assemblies have successfully completed the initial target average burnup of ∼16,000 MWD/T. Enhancing the burnup target of the MOX fuels and increasing loading of MOX fuels in TAPS core will depend on the feedback information generated from the measurement of released fission gases. Fission gas release behaviour has been studied in the experimental MOX fuel elements (UO 2 - 4% PuO 2 ) irradiated in pressurised water loop (PWL) of CIRUS. Eight (8) MOX fuel elements irradiated to an average burnup of ∼16,000 MWD/T have been examined. Some of these fuel elements contained controlled porosity pellets and chamfered pellets. This paper presents the design details of the experimental set up for studying fission gas release behaviour including measurement of gas pressure, void volume and gas composition. The experimental data generated is compared with the prediction of fuel performance modeling codes of PROFESS and GAPCON THERMAL-3. (author)

  6. A numerical model of heavy gas dispersion

    International Nuclear Information System (INIS)

    Bidokhtti, A.A.

    1993-01-01

    A simple mathematical model describing the motion of a dense gas released continuously into and environment is presented. The model correctly predicts the laboratory experiments which were carried out by Britter and Snyder (1987). It is an entrainment model better known as box model. In this model, the effects of temperature change and phase change are not considered and it is for a steady-state case. Further work is required for including these effects which are often associated with the mechanisms involved in accidental or natural release of heavy gases in the environment. The results of such a model will be extended to the practical situations which are and will be common to the nuclear industry at the Atomic Energy Organization of Iran. The applicability of such studies to these situations will be discussed

  7. A fission gas release model

    Energy Technology Data Exchange (ETDEWEB)

    Denis, A; Piotrkowski, R [Argentine Atomic Energy Commission, Buenos Aires (Argentina)

    1997-08-01

    The hypothesis contained in the model developed in this work are as follows. The UO{sub 2} is considered as a collection of spherical grains. Nuclear reactions produce fission gases, mainly Xe and Kr, within the grains. Due to the very low solubility of these gases in UO{sub 2}, intragranular bubbles are formed, of a few nanometers is size. The bubbles are assumed to be immobile and to act as traps which capture gas atoms. Free atoms diffuse towards the grain boundaries, where they give origin to intergranular, lenticular bubbles, of the order of microns. The gas atoms in bubbles, either inter or intragranular, can re-enter the matrix through the mechanism of resolution induced by fission fragment impact. The amount of gas stored in intergranular bubbles grows up to a saturation value. Once saturation is reached, intergranular bubbles inter-connect and the gas in excess is released through different channels to the external surface of the fuel. The resolution of intergranular bubbles particularly affects the region of the grain adjacent to the grain boundary. During grain growth, the grain boundary traps the gas atoms, either free or in intragranular bubbles, contained in the swept volume. The grain boundary is considered as a perfect sink, i.e. the gas concentration is zero at that surface of the grain. Due to the spherical symmetry of the problem, the concentration gradient is null at the centre of the grain. The diffusion equation was solved using the implicit finite difference method. The initial solution was analytically obtained by the Laplace transform. The calculations were performed at different constant temperatures and were compared with experimental results. They show the asymptotic growth of the grain radius as a function of burnup, the gas distribution within the grain at every instant, the growth of the gas content at the grain boundary up to the saturation value and the fraction of gas released by the fuel element referred to the total gas generated

  8. Morphology of Gas Release in Physical Simulants

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

    2014-07-03

    This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

  9. Investigation of delayed fission gas release

    International Nuclear Information System (INIS)

    Cayet, Nicolas

    1996-05-01

    The study of the fission gas release process in the high burnup rig IFA-562 has revealed a particular fuel behaviour: a delay in the fission gas release process. It appeared that an important release of gas was measured by the pressure transducers once the power had decreased, whereas, during steady-state operation, the pressure did not increase very much. After examinations, the gap size has been concluded to be the main parameter involving this delay. However the burnup could have been a potential factor, its role is mainly to close the gap by swelling. The observations of low burnup rods have shown the same delayed fission gas release, the gap being small by design and closed essentially by thermal expansion. The study of the kinetics has demonstrated the time-independency of the phenomenon. Thus the proposed mechanism driving this delayed fission gas release would involve three consecutives stages. During steady-state, the gas is released into the interlinkage network of grain boundary bubbles and cracks. Due to the closed gap, the gas is trapped in some void volumes, unable to escape the pellet. During power reduction, the gap and some old/new cracks open, immediately providing a path for the gas to the pressure transducers and explaining this delay in the fission gas release. (author)

  10. The Jarvis gas release incident

    International Nuclear Information System (INIS)

    Manocha, J.

    1992-01-01

    On 26 September, 1991, large volumes of natural gas were observed to be leaking from two water wells in the Town of Jarvis. Gas and water were being ejected from a drilled water well, at which a subsequent gas explosion occurred. Measurements of gas concentrations indicated levels far in excess of the lower flammability limit at several locations. Electrical power and natural gas services were cut off, and residents were evacuated. A state of emergency was declared, and gas was found to be flowing from water wells, around building foundations, and through other fractures in the ground. By 27 September the volumes of gas had reduced substantially, and by 30 September all residents had returned to their homes and the state of emergency was cancelled. The emergency response, possible pathways of natural gas into the aquifer, and public relations are discussed. It is felt that the likelihood of a similar incident occurring in the future is high. 11 figs

  11. Uncertainties in gas dispersion at the Bruce heavy water plant

    International Nuclear Information System (INIS)

    Alp, E.; Ciccone, A.

    1995-07-01

    There have been concerns regarding the uncertainties in atmospheric dispersion of gases released from the Bruce Heavy Water Plant (BHWP). The concern arises due to the toxic nature of H 2 S, and its combustion product SO 2 . In this study, factors that contribute to the uncertainties, such as the effect of the shoreline setting, the potentially heavy gas nature of H 2 S releases, and concentration fluctuations, have been investigated. The basic physics of each of these issues has been described along with fundamental modelling principles. Recommendations have been provided on available computer models that would be suitable for modelling gas dispersion in the vicinity of the BHWP. (author). 96 refs., 4 tabs., 25 figs

  12. Uncertainties in gas dispersion at the Bruce heavy water plant

    Energy Technology Data Exchange (ETDEWEB)

    Alp, E; Ciccone, A [Concord Environmental Corp., Downsview, ON (Canada)

    1995-07-01

    There have been concerns regarding the uncertainties in atmospheric dispersion of gases released from the Bruce Heavy Water Plant (BHWP). The concern arises due to the toxic nature of H{sub 2}S, and its combustion product SO{sub 2}. In this study, factors that contribute to the uncertainties, such as the effect of the shoreline setting, the potentially heavy gas nature of H{sub 2}S releases, and concentration fluctuations, have been investigated. The basic physics of each of these issues has been described along with fundamental modelling principles. Recommendations have been provided on available computer models that would be suitable for modelling gas dispersion in the vicinity of the BHWP. (author). 96 refs., 4 tabs., 25 figs.

  13. Validation of OpenFoam for heavy gas dispersion applications.

    Science.gov (United States)

    Mack, A; Spruijt, M P N

    2013-11-15

    In the present paper heavy gas dispersion calculations were performed with OpenFoam. For a wind tunnel test case, numerical data was validated with experiments. For a full scale numerical experiment, a code to code comparison was performed with numerical results obtained from Fluent. The validation was performed in a gravity driven environment (slope), where the heavy gas induced the turbulence. For the code to code comparison, a hypothetical heavy gas release into a strongly turbulent atmospheric boundary layer including terrain effects was selected. The investigations were performed for SF6 and CO2 as heavy gases applying the standard k-ɛ turbulence model. A strong interaction of the heavy gas with the turbulence is present which results in a strong damping of the turbulence and therefore reduced heavy gas mixing. Especially this interaction, based on the buoyancy effects, was studied in order to ensure that the turbulence-buoyancy coupling is the main driver for the reduced mixing and not the global behaviour of the turbulence modelling. For both test cases, comparisons were performed between OpenFoam and Fluent solutions which were mainly in good agreement with each other. Beside steady state solutions, the time accuracy was investigated. In the low turbulence environment (wind tunnel test) which for both codes (laminar solutions) was in good agreement, also with the experimental data. The turbulent solutions of OpenFoam were in much better agreement with the experimental results than the Fluent solutions. Within the strong turbulence environment, both codes showed an excellent comparability. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Gas Release as a Deformation Signal

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Radiogenic noble gases are contained in crustal rock at inter and intra granular sites. The gas composition depends on lithology, geologic history, fluid phases, and the aging effect by decay of U, Th, and K. The isotopic signature of noble gases found in rocks is vastly different than that of the atmosphere which is contributed by a variety of sources. When rock is subjected to stress conditions exceeding about half its yield strength, micro-cracks begin to form. As rock deformation progresses a fracture network evolves, releasing trapped noble gases and changing the transport properties to gas migration. Thus, changes in gas emanation and noble gas composition from rocks could be used to infer changes in stress-state and deformation. The purpose of this study has been to evaluate the effect of deformation/strain rate upon noble gas release. Four triaxial experiments were attempted for a strain rate range of %7E10-8 /s (180,000s) to %7E 10-4/s (500s); the three fully successful experiments (at the faster strain rates) imply the following: (1) helium is measurably released for all strain rates during deformation, this release is in amounts 1-2 orders of magnitude greater than that present in the air, and (2) helium gas release increases with decreasing strain rate.

  15. Deep Sludge Gas Release Event Analytical Evaluation

    International Nuclear Information System (INIS)

    Sams, Terry L.

    2013-01-01

    Long Abstract. Full Text. The purpose of the Deep Sludge Gas Release Event Analytical Evaluation (DSGRE-AE) is to evaluate the postulated hypothesis that a hydrogen GRE may occur in Hanford tanks containing waste sludges at levels greater than previously experienced. There is a need to understand gas retention and release hazards in sludge beds which are 200 -300 inches deep. These sludge beds are deeper than historical Hanford sludge waste beds, and are created when waste is retrieved from older single-shell tanks (SST) and transferred to newer double-shell tanks (DST).Retrieval of waste from SSTs reduces the risk to the environment from leakage or potential leakage of waste into the ground from these tanks. However, the possibility of an energetic event (flammable gas accident) in the retrieval receiver DST is worse than slow leakage. Lines of inquiry, therefore, are (1) can sludge waste be stored safely in deep beds; (2) can gas release events (GRE) be prevented by periodically degassing the sludge (e.g., mixer pump); or (3) does the retrieval strategy need to be altered to limit sludge bed height by retrieving into additional DSTs? The scope of this effort is to provide expert advice on whether or not to move forward with the generation of deep beds of sludge through retrieval of C-Farm tanks. Evaluation of possible mitigation methods (e.g., using mixer pumps to release gas, retrieving into an additional DST) are being evaluated by a second team and are not discussed in this report. While available data and engineering judgment indicate that increased gas retention (retained gas fraction) in DST sludge at depths resulting from the completion of SST 241-C Tank Farm retrievals is not expected and, even if gas releases were to occur, they would be small and local, a positive USQ was declared (Occurrence Report EM-RP--WRPS-TANKFARM-2012-0014, 'Potential Exists for a Large Spontaneous Gas Release Event in Deep Settled Waste Sludge'). The purpose of this technical

  16. TOXRISK, Toxic Gas Release Accident Analysis

    International Nuclear Information System (INIS)

    Bennett, D.E.; Chanin, D.I.; Shiver, A.W.

    1993-01-01

    1 - Description of program or function: TOXRISK is an interactive program developed to aid in the evaluation of nuclear power plant control room habitability in the event of a nearby toxic material release. The program uses a model which is consistent with the approach described in the NRC Regulatory Guide 1.78. Release of the gas is treated as an initial puff followed by a continuous plume. The relative proportions of these as well as the plume release rate are supplied by the user. Transport of the gas is modeled as a Gaussian distribution and occurs through the action of a constant velocity, constant direction wind. Great flexibility is afforded the user in specifying the release description, meteorological conditions, relative geometry of the accident and plant, and the plant ventilation system characteristics. Two types of simulation can be performed: multiple case (parametric) studies and probabilistic analyses. Upon execution, TOXRISK presents a menu, and the user chooses between the Data Base Manager, the Multiple Case program, and the Probabilistic Study Program. The Data Base Manager provides a convenient means of storing, retrieving, and modifying blocks of data required by the analysis programs. The Multiple Case program calculates resultant gas concentrations inside the control room and presents a summary of information that describes the event for each set of conditions given. Optimally, a time history profile of inside and outside concentrations can also be produced. The Probabilistic Study program provides a means for estimating the annual probability of operator incapacitation due to toxic gas accidents on surrounding transportation routes and storage sites. 2 - Method of solution: Dispersion or diffusion of the gas during transport is described by modified Pasquill-Gifford dispersion coefficients

  17. Probabilistic consequence assessment of hydrogen sulphide releases from a heavy water plant

    International Nuclear Information System (INIS)

    1983-06-01

    This report is the second in a series concerned with the evaluation of the consequences to the public of an accidental release of hydrogen sulphide (H 2 S) to the atmosphere following a pipe or pressure envelope failure, or some other process upset, at a heavy water plant. It consists of documentation of the code GASPROB, which has been developed to provide consequence probabilities for a range of postulated releases. The code includes mathematical simulations of initial gas behaviour upon release to the atmosphere, such as gravitational settling of a cold release and the rise of jets and flares, subsequent atmospheric dispersion under a range of weather conditions, and the toxic effects on the exposed population. The code makes use of the site-specific dispersion climatology, topography and population distribution, as well as the probabilistic lethal dose data for the released gas. Output for a given postulated release can be provided in terms of the concentration of the gas at ground level around the point of release, projected numbers of fatalities within specified areas and the projected total fatalities regardless of location. This report includes a general description of GASPROB, and specifics of the code structure, the function of each subroutine, input and output data, and the permanent data files established. Three appendices to the report contain a complete code listing, detailed subroutine descriptions and a sample output

  18. The generalized heavy free gas thermalization operator

    International Nuclear Information System (INIS)

    Pitcher, H.H.W.

    1963-05-01

    This paper gives an introduction to the generalized heavy free gas (Horowitz) thermalization operator, which is a device for simplifying thermalization calculations. Analytical, experimental,and numerical methods for determining the energy-dependent function f in the operator are discussed. The dependence of f on the nature of the moderator, its temperature, and the absorption of the system are investigated, using a program FOCS which derives f's from DSN (multigroup) thermal spectra; it is found that for most purposes the dependence on absorption is negligible except when Pu240 is present. The sensitivity of calculated spectra and reaction rate to changes in f is considered. f is given for graphite at 300 and 600 deg. K. (author)

  19. Gas release from pressurized closed pores in nuclear fuels

    International Nuclear Information System (INIS)

    Bailey, P.; Donnelly, S.E.; Armour, D.G.; Matzke, H.

    1988-01-01

    Gas release from the nuclear fuels UO 2 and UN out of pressurized closed pores produced by autoclave anneals has been studied by Thermal Desorption Spectrometry (TDS). Investigation of gas release during heating and cooling has indicated stress related mechanical effects leading to gas release. This release occurred in a narrow temperature range between about 1000 and 1500 K for UO 2 , but it continued down to ambient temperature for UN. No burst release was observed above 1500 K for UO 2 . (orig.)

  20. Heavy water moderated gas-cooled reactors

    International Nuclear Information System (INIS)

    Bailly du Bois, B.; Bernard, J.L.; Naudet, R.; Roche, R.

    1964-01-01

    France has based its main effort for the production of nuclear energy on natural Uranium Graphite-moderated gas-cooled reactors, and has a long term programme for fast reactors, but this country is also engaged in the development of heavy water moderated gas-cooled reactors which appear to present the best middle term prospects. The economy of these reactors, as in the case of Graphite, arises from the use of natural or very slightly enriched Uranium; heavy water can take the best advantages of this fuel cycle and moreover offers considerable development potential because of better reactor performances. A prototype plant EL 4 (70 MW) is under construction and is described in detail in another paper. The present one deals with the programme devoted to the development of this reactor type in France. Reasons for selecting this reactor type are given in the first part: advantages and difficulties are underlined. After reviewing the main technological problems and the Research and Development carried out, results already obtained and points still to be confirmed are reported. The construction of EL 4 is an important step of this programme: it will be a significant demonstration of reactor performances and will afford many experimentation opportunities. Now the design of large power reactors is to be considered. Extension and improvements of the mechanical structures used for EL 4 are under study, as well as alternative concepts. The paper gives some data for a large reactor in the present state of technology, as a result from optimization studies. Technical improvements, especially in the field of materials could lead to even more interesting performances. Some prospects are mentioned for the long run. Investment costs and fuel cycles are discussed in the last part. (authors) [fr

  1. Comparison of FISGAS swelling and gas release predictions with experiment

    International Nuclear Information System (INIS)

    Ostensen, R.W.

    1979-01-01

    FISGAS calculations were compared to fuel swelling data from the FD1 tests and to gas release data from the FGR39 test. Late swelling and gas release predictions are satisfactory if vacancy depletion effects are added to the code. However, early swelling predictions are not satisfactory, and early gas release predictions are very poor. Explanation of these discrepancies is speculative

  2. Tritium release reduction and radiolysis gas formation

    Energy Technology Data Exchange (ETDEWEB)

    Batifol, G.; Douche, Ch.; Sejournant, Ch. [CEA Valduc, 21 - Is-sur-Tille (France)

    2008-07-15

    At CEA Valduc, the usual tritiated waste container is the steel drum. It allows good release reduction performance for middle activity waste but in some cases tritium outgassing from the waste drums is too high. It was decided to over-package each drum in a tighter container called the over-drum. According to good safety practices it was also decided to measure gas composition evolution into the over-drum in order to defect hydrogen formation over time. After a few months, a significant release reduction was observed. Additionally there followed contamination reduction in the roof storage building rainwater. However hydrogen was also observed in some over-drums, in addition to other radiolysis products. Catalyst will be added to manage the hydrogen risk in the over-drums. (authors)

  3. Heavy gas oils as feedstock for petrochemicals

    Energy Technology Data Exchange (ETDEWEB)

    Clark, P.D. [Nova Chemicals Ltd., Calgary, AB (Canada); Du Plessis, D. [Alberta Energy Research Inst., Edmonton, AB (Canada)]|[Alberta Economic Development and Trade, Edmonton, AB (Canada)

    2004-07-01

    This presentation reviewed the possibilities for converting heavy aromatic compounds and gas oils obtained from Alberta bitumen into competitively priced feedstock for high value refined products and petrochemicals. Upgrading bitumen beyond synthetic crude oil to refined products and petrochemicals would add value to bitumen in Alberta by expanding the petrochemical industry by providing a secure market for co-products derived from the integration of bitumen upgrading and refining. This presentation also reviewed conventional feedstocks and processes; by-products from bitumen upgrading and refining; production of light olefins by the fluid catalytic cracking (FCC) and hydrocracking process; deep catalytic cracking, catalytic pyrolysis and PetroFCC processes; technical and economic evaluations; and opportunities and challenges. Conventional feeds for steam cracking were listed along with comparative yields on feedstock. The use of synthetic gas liquids from oil sands plants was also reviewed. Current FCC type processes for paraffinic feedstocks are not suitable for Alberta's bitumen, which require better technologies based on hydrotreating and new ring opening catalysts. tabs., figs.

  4. Fission gas release in LWR fuel measured during nuclear operation

    International Nuclear Information System (INIS)

    Appelhans, A.D.; Skattum, E.; Osetek, D.J.

    1980-01-01

    A series of fuel behavior experiments are being conducted in the Heavy Boiling Water Reactor in Halden, Norway, to measure the release of Xe, Kr, and I fission products from typical light water reactor design fuel pellets. Helium gas is used to sweep the Xe and Kr fission gases out of two of the Instrumented Fuel Assembly 430 fuel rods and to a gamma spectrometer. The measurements of Xe and Kr are made during nuclear operation at steady state power, and for 135 I following reactor scram. The first experiments were conducted at a burnup of 3000 MWd/t UO 2 , at bulk average fuel temperatures of approx. 850 K and approx. 23 kW/m rod power. The measured release-to-birth ratios (R/B) of Xe and Kr are of the same magnitude as those observed in small UO 2 specimen experiments, when normalized to the estimated fuel surface-to-volume ratio. Preliminary analysis indicates that the release-to-birth ratios can be calculated, using diffusion coefficients determined from small specimen data, to within a factor of approx. 2 for the IFA-430 fuel. The release rate of 135 I is shown to be approximately equal to that of 135 Xe

  5. Noble Gas Release Signal as a Precursor to Fracture

    Science.gov (United States)

    Bauer, S. J.; Lee, H.; Gardner, W. P.

    2017-12-01

    We present empirical results of rock strain, microfracturing, acoustic emissions, and noble gas release from laboratory triaxial experiments for a granite, basalt, shale and bedded rock salt. Noble gases are released and measured real-time during deformation using mass spectrometry. The gas release represents a precursive signal to macrofracture. Gas release is associated with increased acoustic emissions indicating that microfracturing is required to release gas and create pathways for the gas to be sensed. The gas released depends on initial gas content, pore structure and its evolution during deformation, the deformation amount, matrix permeability, deformation style and the stress/strain history. Gases are released from inter and intracrystalline sites; release rate increases as strain and microfracturing increases. The gas composition depends on lithology, geologic history and age, fluids present, and radioisotope concentrations that affect radiogenic noble gas isotope (e.g. 4He,40Ar) production. Noble gas emission and its relationship to crustal processes such as seismicity and volcanism, tectonic velocities, qualitative estimates of deep permeability, age dating of groundwater, and a signature of nuclear weapon detonation. Our result show that mechanical deformation of crustal materials is an important process controlling gas release from rocks and minerals, and should be considered in techniques which utilize gas release and/or accumulation. We propose using noble gas release to signal rock deformation in boreholes, mines and waste repositories. We postulate each rock exhibits a gas release signature which is microstructure, stress, strain, and/or permanent deformation dependent. Calibration of such relationships, for example relating gas release per rock unit volume to strain may be used to quantify rock deformation and develop predictive models.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and

  6. Nondestructive fission gas release measurement and analysis

    International Nuclear Information System (INIS)

    O'Leary, P.M.; Packard, D.R.

    1993-01-01

    Siemens Power Corporation (SPC) has performed reactor poolside gamma scanning measurements of fuel rods for fission gas release (FGR) detection for more than 10 yr. The measurement system has been previously described. Over the years, the data acquisition system, the method of spectrum analysis, and the means of reducing spectrum interference have been significantly improved. A personal computer (PC)-based multichannel analyzer (MCA) package is used to collect, display, and store high-resolution gamma-ray spectra measured in the fuel rod plenum. A PC spread sheet is used to fit the measured spectra and compute sample count rates after Compton background subtraction. A Zircaloy plenum spacer is often used to reduce positron annihilation interference that can arise from the INCONEL reg-sign plenum spring used in SPC-manufactured fuel rods

  7. Transient fission gas release during direct electrical heating experiments

    International Nuclear Information System (INIS)

    Fenske, G.R.; Emerson, J.E.; Savoie, F.E.

    1983-12-01

    The gas release behavior of irradiated EBR-II fuel was observed to be dependent on several factors: the presence of cladding, the retained gas content, and the energy absorbed. Fuel that retained in excess of 16 to 17 μmoles/g of fission gas underwent spallation as the cladding melted and released 22 to 45% of its retained gas, while fuel with retained gas levels below approx. 15 to 16 μmoles/g released less than approx. 9% of its gas as the cladding melted. During subsequent direct electrical heating ramps, fuel that did not spall released an additional quantity of gas (up to 4 μmoles/g), depending on the energy absorbed

  8. Heavy ion source support gas mixing experiments

    International Nuclear Information System (INIS)

    Hudson, E.D.; Mallory, M.L.

    1977-01-01

    Experiments on mixing an easily ionized support gas with the primary ion source gas have produced large beam enhancements for high charge state light ions (masses less than or equal to 20). In the Oak Ridge Isochronous Cyclotron (ORIC), the beam increase has been a factor of 5 or greater, depending on ion species and charge state. Approximately 0.1 cc/min of the easily ionized support gas (argon, krypton, or xenon) is supplied to the ion source through a separate gas line and the primary gas flow is reduced by approximately 30 percent. The proposed mechanism for increased intensity is as follows: The heavier support gas ionizes readily to a higher charge state, providing increased cathode heating. The increased heating permits a reduction in primary gas flow (lower pressure) and the subsequent beam increase

  9. Considerations in modeling fission gas release during normal operation

    International Nuclear Information System (INIS)

    Rumble, E.T.; Lim, E.Y.; Stuart, R.G.

    1977-01-01

    The EPRI LWR fuel rod modeling code evaluation program analyzed seven fuel rods with experimental fission gas release data. In these cases, rod-averged burnups are less than 20,000 MWD/MTM, while the fission gas release fractions range roughly from 2 to 27%. Code results demonstrate the complexities in calculating fission gas release in certain operating regimes. Beyond this work, the behavior of a pre-pressurized PWR rod is simulated to average burnups of 40,000 MWD/MTM using GAPCON-THERMAL-2. Analysis of the sensitivity of fission gas release to power histories and release correlations indicate the strong impact that LMFBR type release correlations induce at high burnup. 15 refs

  10. Gas stripping and recirculation process in heavy water separation plant

    International Nuclear Information System (INIS)

    Nazzer, D.B.; Thayer, V.R.

    1976-01-01

    Hydrogen sulfide is stripped from hot effluent, in a heavy water separation plant of the dual temperature isotope separation type, by taking liquid effluent from the hot tower before passage through the humidifier, passing the liquid through one or more throttle devices to flash-off the H 2 S gas content, and feeding the gas into an absorption tower containing incoming feed water, for recycling of the gas through the process

  11. Role of fission gas release in reactor licensing

    International Nuclear Information System (INIS)

    1975-11-01

    The release of fission gases from oxide pellets to the fuel rod internal voidage (gap) is reviewed with regard to the required safety analysis in reactor licensing. Significant analyzed effects are described, prominent gas release models are reviewed, and various methods used in the licensing process are summarized. The report thus serves as a guide to a large body of literature including company reports and government documents. A discussion of the state of the art of gas release analysis is presented

  12. Fission gas release from fuel at high burnup

    International Nuclear Information System (INIS)

    Meyer, R.O.; Beyer, C.E.; Voglewede, J.C.

    1978-03-01

    The release of fission gas from fuel pellets at high burnup is reviewed in the context of the safety analysis performed for reactor license applications. Licensing actions are described that were taken to correct deficient gas release models used in these safety analyses. A correction function, which was developed by the Nuclear Regulatory Commission staff and its consultants, is presented. Related information, which includes some previously unpublished data, is also summarized. The report thus provides guidance for the analysis of high burnup gas release in licensing situations

  13. Distribution of heavy metals from flue gas in algal bioreactor

    Science.gov (United States)

    Napan, Katerine

    Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

  14. Fission gas release of MOX with heterogeneous structure

    International Nuclear Information System (INIS)

    Nakae, N.; Akiyama, H.; Kamimura, K; Delville, R.; Jutier, F.; Verwerft, M.; Miura, H.; Baba, T.

    2015-01-01

    It is very useful for fuel integrity evaluation to accumulate knowledge base on fuel behavior of uranium and plutonium mixed oxide (MOX) fuel used in light water reactors (LWRs). Fission gas release is one of fuel behaviors which have an impact on fuel integrity evaluation. Fission gas release behavior of MOX fuels having heterogeneous structure is focused in this study. MOX fuel rods with a heterogeneous fuel microstructure were irradiated in Halden reactor (IFA-702) and the BR-3/BR-2 CALLISTO Loop (CHIPS program). The 85 Kr gamma spectrometry measurements were carried out in specific cycles in order to examine the concerned LHR (Linear Heat Rate) for fission gas release in the CHIPS program. The concerned LHR is defined in this paper to be the LHR at which a certain additional fission gas release thermally occurs. Post-irradiation examination was performed to understand the fission gas release behavior in connection with the pellet microstructure. The followings conclusions can be made from this study. First, the concerned LHR for fission gas release is estimated to be in the range of 20-23 kW/m with burnup over 37 GWd/tM. It is moreover guessed that the concerned LHR for fission gas release tends to decrease with increasing burnup. Secondly It is observed that FGR (fission gas release rate) is positively correlated with LHR when the LHR exceeds the concerned value. Thirdly, when burnup dependence of fission gas release is discussed, effective burnup should be taken into account. The effective burnup is defined as the burnup at which the LHR should be exceed the concerned value at the last time during all the irradiation period. And fourthly, it appears that FGR inside Pu spots is higher than outside and that retained (not released) fission gases mainly exist in the fission gas bubbles. Since fission gases in bubbles are considered to be easily released during fuel temperature increase, this information is very important to estimate fission gas release behavior

  15. A simple operational gas release and swelling model. Pt. 1

    International Nuclear Information System (INIS)

    Wood, M.H.; Matthews, J.R.

    1980-01-01

    A new and simple model of fission gas release and swelling has been developed for oxide nuclear fuel under operational conditions. The model, which is to be incorporated into a fuel element behaviour code, is physically based and applicable to fuel at both thermal and fast reactor ratings. In this paper we present that part of the model describing the behaviour of intragranular gas: a future paper will detail the treatment of the grain boundary gas. The results of model calculations are compared with recent experimental observations of intragranular bubble concentrations and sizes, and gas release from fuel irradiated under isothermal conditions. Good agreement is found between experiment and theory. (orig.)

  16. HEAVY-DUTY GREENHOUSE GAS EMISSIONS MODEL ...

    Science.gov (United States)

    Class 2b-8 vocational truck manufacturers and Class 7/8 tractor manufacturers would be subject to vehicle-based fuel economy and emission standards that would use a truck simulation model to evaluate the impact of the truck tires and/or tractor cab design on vehicle compliance with any new standards. The EPA has created a model called “GHG Emissions Model (GEM)”, which is specifically tailored to predict truck GHG emissions. As the model is designed for the express purpose of vehicle compliance demonstration, it is less configurable than similar commercial products and its only outputs are GHG emissions and fuel consumption. This approach gives a simple and compact tool for vehicle compliance without the overhead and costs of a more sophisticated model. Evaluation of both fuel consumption and CO2 emissions from heavy-duty highway vehicles through a whole-vehicle operation simulation model.

  17. Validation of OpenFoam for heavy gas dispersion applications

    NARCIS (Netherlands)

    Mack, A.; Spruijt, M.P.N.

    2013-01-01

    In the present paper heavy gas dispersion calculations were performed with OpenFoam. For a windtunnel test case, numerical data was validated with experiments. For a full scale numerical experiment,a code to code comparison was performed with numerical results obtained from Fluent. The validationwas

  18. Heavy-Ion-Induced Electronic Desorption of Gas from Metals

    CERN Document Server

    Molvik, A W; Mahner, E; Kireeff Covo, M; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Krämer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2007-01-01

    During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion-induced gas desorption scales with the electronic energy loss (dEe/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  19. Towards a mechanistic understanding of transient fission gas release

    International Nuclear Information System (INIS)

    Matthews, J.R.; Small, G.J.

    1989-01-01

    Recent experimental results on transient fission gas release from oxide fuels are briefly reviewed. These together with associated microstructural observations are compared with the main models for fission gas behaviour. Single gas atom diffusion, bubble migration, heterogeneous percolation and grain boundary sweeping are examined as possible release mechanisms. The role of gas trapping in bubbles and re-solution by irradiation and thermal processes are included in the comparison. As much of the data, and the main range of interest for light water reactor fuels, is for release during mild transients in fuel with a burn-up below 4%, the role of gas retention on grain boundaries is very important and in some cases dominant. The grain boundaries are found to respond very differently to various gas arrival rates and to local temperature conditions. This can lead to early interlinkage and release in some cases, but retention with accompanying large swelling in others. The role of fission products and the local oxygen content of the fuel are found to be important. The effective fuel stoichiometry is likely to change significantly during transients with substantial effects on the transport processes controlling fission gas behaviour. The results of the evaluation of the models are summarized in mechanism maps for intragranular and grain boundary behaviour. (author). 36 refs, 8 figs

  20. Releasing characteristics and fate of heavy metals from phytoremediation crop residues during anaerobic digestion.

    Science.gov (United States)

    Lee, Jongkeun; Park, Ki Young; Cho, Jinwoo; Kim, Jae Young

    2018-01-01

    In this study, lab-scale batch tests were conducted to investigate releasing characteristics of heavy metals according to degradation of heavy metal containing biomass. The fate of heavy metals after released from biomass was also determined through adsorption tests and Visual MINTEQ simulation. According to the anaerobic batch test results as well as volatile solids and carbon balance analyses, maximum of 60% by wt. of biomass was degraded. During the anaerobic biodegradation, among Cd, Cu, Ni, Pb, and Zn, only Cu and Zn were observed in soluble form (approximately 40% by wt. of input mass). The discrepancy between degradation ratio of biomass and ratio of released heavy metals mass from biomass was observed. It seems that this discordance was caused by the fate (i.e., precipitated with sulfur/hydroxide or adsorbed onto sorbents) of each heavy metal types in solution after being released from biomass. Thus, releasing characteristics and fate of heavy metal should be considered carefully to predict stability of anaerobic digestion process for heavy metal-containing biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Mapping reactor operating regimes for heavy gas oil hydrotreating

    Energy Technology Data Exchange (ETDEWEB)

    Munteanu, Mugurel Catalin; Chen, Jinwen [CanmetENERGY, Natural Resources Canada (Canada)

    2011-07-01

    Hydrotreating (HDT) is used in oil refineries at temperatures of 350-400 degree C and pressure of 50-100 bars in a fixed bed to improve the quality of distillate fraction. HDT operates as a gas-liquid-solid process, trickle bed. Efforts have been made to model it but volatilization of liquid oil is often ignored. The aim of this paper is to predict vapor-liquid equilibrium (VLE) for a typical heavy distillate feed in pilot plant hydrotreaters. The study was conducted under various operating conditions and a flash calculation program calibrated in-house was used to predict VLE. VLE values were found and results showed that higher pressure, lower gas/oil ratio and temperature should be used to maintain the desired operating regimes when hydrotreating heavy distillate feed. This study determined the operating conditions for maintaining the desired operating regimes and these findings could be useful for operators.

  2. Probabilistic consequence assessment of hydrogen sulphide releases from a heavy water plant

    International Nuclear Information System (INIS)

    1983-01-01

    This report is concerned with the evaluation of the consequences to the public of an accidental release of hydrogen sulphide (H 2 S) to the atmosphere following a pipe or pressure envelope failure, or some other process upset, at a heavy water plant. It covers the first stage of a programme in which the nature of the problem was analyzed and recommendations made for the implementation of a computer model. The concepts of risk assessment and consequence assessment are discussed and a methodology proposed for combining the various elements of the problem into an overall consequence model. These elements are identified as the 'Initiating Events', 'Route to Receptor' and 'Receptor Response' and each is studied in detail in the report. Such phenomena as the blowdown of H 2 S from a rupture, the initial gas cloud behaviour, atmospheric dispersion and the toxicity of H 2 S and sulphur dioxide (SO 2 ) are addressed. Critical factors are identified and modelling requirements specified, with special reference to the Bruce heavy water plant. Finally, an overall model is recommended for implementation at the next stage of the programme, together with detailed terms of reference for the remaining work

  3. Fission gas release from fuels at high burnup

    International Nuclear Information System (INIS)

    Kauffmann, Yves; Pointud, M.L.; Vignesoult, Nicole; Atabek, Rosemarie; Baron, Daniel.

    1982-04-01

    Determinations of residual gas concentrations by heating and by X microanalysis were respectively carried out on particles (TANGO program) and on sections of fuel rods, perfectly characterized as to fabrication and irradiation history. A threshold release temperature of 1250 0 C+-100 0 C was determined irrespective of the type of oxide and the irradiation history in the 18,000-45,000 MWdt -1 (U) specific burnup field. The overall analyses of gas released from the fuel rods show that, in the PWR operating conditions, the fraction released remains less than 1% up to a mean specific burnup of 35000 MWdt -1 (U). The release of gases should not be a limiting factor in the increase of specific burnups [fr

  4. Jet formation in shock-heavy gas bubble interaction

    Institute of Scientific and Technical Information of China (English)

    Zhi-Gang Zhai; Ting Si; Li-Yong Zou; Xi-Sheng Luo

    2013-01-01

    The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work.The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D.As a validation,the experiments of a SF6 bubble accelerated by a planar shock were performed.The results indicate that,due to the mismatch of acoustic impedance,the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition.With respect to the same bubble,the manner of jet formation is also distinctly different under different shock strengths.The disparities of the acoustic impedance result in different effects of shock focusing in the bubble,and different behaviors of shock wave inside and outside the bubble.The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation.Moreover,the analysis of the vorticity deposition,and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation.It is concluded that the pressure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.

  5. Relative Release-to-Birth Indicators for Investigating TRISO Fuel Fission Gas Release Models

    International Nuclear Information System (INIS)

    Harp, Jason M.; Hawari, Ayman I.

    2008-01-01

    TRISO microsphere fuel is the fundamental fuel unit for Very High Temperature Reactors (VHTR). A single TRISO particle consists of an inner kernel of uranium dioxide or uranium oxycarbide surrounded by layers of pyrolytic carbon and silicon carbide. If the silicon carbide layer fails, fission products, especially the noble fission gases Kr and Xe, will begin to escape the failed particle. The release of fission gas is usually quantified by measuring the ratio of the released activity (R) to the original birth activity (B), which is designated as the R/B ratio. In this work, relative Release-to-Birth indicators (I) are proposed as a technique for interpreting the results of TRISO irradiation experiments. By implementing a relative metric, it is possible to reduce the sensitivity of the indicators to instrumental uncertainties and variations in experimental conditions. As an example, relative R/B indicators are applied to the interpretation of representative data from the Advanced Gas Reactor-1 TRISO fuel experiment that is currently taking place at the Advanced Test Reactor of Idaho National Laboratory. It is shown that the comparison of measured to predicted relative R/B indicators (I) gives insight into the physics of release and helps validate release models. Different trends displayed by the indicators are related to the mechanisms of fission gas release such as diffusion and recoil. The current analysis shows evidence for separate diffusion coefficients for Kr and Xe and supports the need to account for recoil release. (authors)

  6. Using random event simulation to evaluate the effectiveness of indoor sheltering during a sour gas release

    International Nuclear Information System (INIS)

    Wilson, D.

    2003-01-01

    In the event of sour gas releases to the atmosphere, there is a strong bias toward evacuation rather than sheltering-in-place. This paper described the critical factors in decision-making for shelter-in-place versus evacuation. These include: delay time expected before release begins; size of potential release, explosion or fire; expected duration; direction to safety for evacuation; the air tightness of the building; and, the number of people in the emergency response zone. A shelter-in-place decision chart developed by the Canadian Association of Fire Chiefs was presented. It shows the usual bias toward evacuation as the default position. It also shows the greatest drawbacks of sheltering-in-place. The main factor in maintaining the effectiveness of the building shelter is the rate of air infiltration into the building. Other issues to consider include: reactive versus passive chemicals in the release; light versus heavy gas releases; building type (houses, high-rise apartments, office buildings, or warehouses); tightness of building construction; whether to turn the house heating and air conditioning on or off during shelter; daytime versus nighttime conditions; and, cost factors. Equations for calculating indoor and outdoor toxic exposure to decide on shelter versus evacuation were also presented. It was concluded that the absence of peak concentrations dramatically reduce the risk of fatality to people sheltering indoors. Keeping people indoors is the best way to assure their safety for the first hour following a toxic release. 8 refs., 6 figs

  7. Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

    Science.gov (United States)

    Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

    2017-05-01

    Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R 2  > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe 3 O 4 ) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO 3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe 3 O 4 . The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe 6 (OH) 12 CO 3 content under higher sulfate concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Experimental study on the heavy-duty gas turbine combustor

    International Nuclear Information System (INIS)

    Antonovsky, V.; Ahn, Kook Young

    2000-01-01

    The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed in the scale 1:1. The model experiments were executed at a pressure smaller than in the real gas turbine. The combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure, and NOx emission were measured at partial and full load for both model and on-site testing. The comparison of these items of information, received on similar modes in the stand and field tests, has allowed the development of a method of calculation and the improvement of gas turbine combustors

  9. Gas fuelled heavy-duty trucks for municipal services

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, A. (City of Helsinki Construction Services (Finland)); Hietanen, L. (Lassila and Tikanoja, Jyvaeskylae (Finland)); Nylund, N.-O. (TEC TransEnergy Consulting, Espoo (Finland))

    2009-07-01

    Helsinki City Public Works Department (HKR) and the environmental management company Lassila and Tikanoja joined forces to demonstrate the suitability of heavy-duty gas fuelled trucks for municipal services. HKR acquired two and Lassila and Tikanoja five Mercedes-Benz Econic trucks. HKR's trucks are equipped with interchangeable platforms, Lassila an Tikanoja's trucks with refuse collection equipment. The trucks are subjected to a two-year follow-up study to establish reliability, operational costs and exhaust emissions. Diesel trucks representing up-to-date technology are used as reference. If the gas fuelled trucks perform well, this can lead to increased numbers of natural gas trucks in municipal services, and in the long run to the introduction of biogas fuelled trucks. (orig.)

  10. Ultrasound-induced Gas Release from Contrast Agent Microbubbles

    NARCIS (Netherlands)

    Postema, M.A.B.; Postema, Michiel; Bouakaz, Ayache; Versluis, Michel; de Jong, N.

    2005-01-01

    We investigated gas release from two hard-shelled ultrasound contrast agents by subjecting them to high-mechanical index (MI) ultrasound and simultaneously capturing high-speed photographs. At an insonifying frequency of 1.7 MHz, a larger percentage of contrast bubbles is seen to crack than at 0.5

  11. Effects of Operating Conditions on Gas Release Thermal ...

    African Journals Online (AJOL)

    The gas release rates and the flame length of the potential jet fires were initially estimated using Simplex Source Term Models which pay limited attention to operating conditions. Finally a more detailed follow-up study, accounting for a range of practical factors was conducted. A number of useful risk management metrics ...

  12. The effect of gas release on column separator

    NARCIS (Netherlands)

    Kranenburg, C.

    1974-01-01

    A mathematical model has been considered in which the influence of gas release on transient cavitating flow and column separation in pipel ines is taken into account. A rei iable numerical method has been developed for the computation of the wave propagation and cavitation phenomena following pump

  13. The gas release programs to increase competition in the European gas market

    International Nuclear Information System (INIS)

    Clastres, Cedric

    2005-01-01

    Regulators have implemented asymmetric regulation measures, such as gas release programs and market share targets, because of European gas supply features and gas market specificities. Empirical experiences show in line with economic theory that these regulation measures favour entry and competition without deterring investments. If we look at impacts on competition, they are mitigated. Some positive effects result from the increase in consumption or in importation and transportation infrastructure developments. But these regulations can also encourage anti-competitive behaviours like collusion, cream-skimming, reverse cherry picking or inefficient entries. Gas release measures establish a link between the incumbent and its competitors. A system of constraints on operators capacities can also appear. Thus, pricing or quantity strategies are more complex. Equilibrium prices are more volatile and very different of competition mark-up. The incumbent, for high gas release quantities and low supplies, can increase its costs to make more profit. This Raising Rivals' Costs strategy often occur if the gas release price is closer to supply costs. This strategy does not impact on consumers surplus but decreases welfare. The regulator can restore incentives to efficiency by setting gas release proportion function of incumbent's supplies. This proportion must be high enough to have a positive impact on the market because of incumbent's incentives to efficiency and greater total quantities sold by the two operators. But, on another way, it must not be too high as it could, thus, increase the probability of Raising Rivals' Costs or favour collusive strategies. (author) [fr

  14. Release of Inorganic Elements during Wood Combustion. Release to the Gas Phase of Inorganic Elements during: Wood Combustion. Part 1: Development and Evaluation of Quantification Methods

    DEFF Research Database (Denmark)

    van Lith, Simone Cornelia; Alonso-Ramírez, Violeta; Jensen, Peter Arendt

    2006-01-01

    During wood combustion, inorganic elements such as alkali metals, sulfur, chlorine, and some heavy metals are partly released to the gas phase, which may cause problems in combustion facilities because of deposit formation and corrosion. Furthermore, it may cause harmful emissions of gases......) in this reactor, whereas methods B and C involved initial pyrolysis and combustion, respectively, of a large fuel sample (~5 kg) in a bench-scale fixed-bed reactor at 500 C. The methods were evaluated by comparing the data on the release of Cl, S, K, Na, Zn, and Pb from fiber board obtained by the three methods...

  15. The present status of rare gas release control

    International Nuclear Information System (INIS)

    Yamamoto, Hiroshi

    1974-01-01

    Of the rare gases Ar, Kr and Xe released from nuclear facilities, the problem of release control can be confined to 41 Ar, 85 Kr and 133 Xe. The cases of the latter two are described, as 41 Ar is not much significant. 133 Xe, having relatively short half-life, can be dealt sufficiently by holding-up in case of light water reactors. 85 Kr of long half-life must be removed : the methods are low temperature adsorption, liquefaction distillation, absorption and diaphragm method. As for future problem, there is disposal of concentrated rare gas. (Mori, K.)

  16. The effects of fission gas release on PWR fuel rod design and performance

    International Nuclear Information System (INIS)

    Leech, W.J.; Kaiser, R.S.

    1980-01-01

    The purpose of this investigation was to determine the effects of fission gas release on PWR fuel rod design and performance. Empirical models were developed from fission gas release data. Fission gas release during normal operation is a function of burnup. There is little additional fission gas release during anticipated transients. The empirical models were used to evaluate Westinghouse fuel rod designs. It was determined that fission gas release is not a limiting parameter for obtaining rod average burnups in the range of 50,000 to 60,000 MWD/MTU. Fission gas release during anticipated transients has a negligible effect on the margins to rod design limits. (author)

  17. Investigation of heavy metals release from sediment with bioturbation/bioirrigation.

    Science.gov (United States)

    He, Yi; Men, Bin; Yang, Xiaofang; Li, Yaxuan; Xu, Hui; Wang, Dongsheng

    2017-10-01

    Bioturbation/bioirrigation can affect the remobilization of metals from sediments. In this study, experiments were performed to examine the effect of bioturbation/bioirrigation by different organisms on cadmium (Cd), copper (Cu), zinc (Zn) and lead (Pb) releasing from the spiked sediment. The diffusive gradient in thin films technique (DGT) revealed that at the end of exposure time, the labile heavy metals concentrations in the pore water for all metal and organisms combinations except Cu and chironomid larvae were much lower than that in the control group. However, the concentrations of heavy metals detected by the DGT were virtually indistinguishable among the treatments with tubificid, chironomid larvae and loach. The correlation analysis of heavy metals with iron (Fe) and manganese (Mn) suggested that Cd, Zn and Pb were most likely bound as Fe-Mn oxidation form in the pore water, but Cu was in other forms. After 28 d of exposure, bioturbation/bioirrigation produced a significant release of particulate heavy metals into the overlying water, especially in the treatment with loach. The bioturbation/bioirrigation impact on the Pb remobilization was less than the other three heavy metals. The effects of bioturbaiton/bioirrigation on the heavy metals remobilization in the sediment were complex that with studying the heavy metals remobilization in the sediment and water interface, the biological indicators should be recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Clean coal and heavy oil technologies for gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Todd, D.M. [GE Industrial & Power Systems, Schenectady, NY (United States)

    1994-12-31

    Global power generation markets have shown a steady penetration of GT/CC technology into oil and gas fired applications as the technology has matured. The lower cost, improved reliability and efficiency advantages of combined cycles can now be used to improve the cost of electricity and environmental acceptance of poor quality fuels such as coal, heavy oil, petroleum coke and waste products. Four different technologies have been proposed, including slagging combustors, Pressurized Fluidized Bed Combustion (PFBC), Externally Fired Combined Cycle (EFCC) and Integrated Gasification Combined Cycle (IGCC). Details of the technology for the three experimental technologies can be found in the appendix. IGCC is now a commercial technology. In the global marketplace, this shift is being demonstrated using various gasification technologies to produce a clean fuel for the combined cycle. Early plants in the 1980s demonstrated the technical/environmental features and suitability for power generation plants. Economics, however, were disappointing until the model F GT technologies were first used commercially in 1990. The economic break-through of matching F technology gas turbines with gasification was not apparent until 1993 when a number of projects were ordered for commercial operation in the mid-1990s. GE has started 10 new projects for operation before the year 2000. These applications utilize seven different gasification technologies to meet specific application needs. Early plants are utilizing low-cost fuels, such as heavy oil or petroleum coke, to provide economics in first-of-a-kind plants. Some special funding incentives have broadened the applications to include power-only coal plants. Next generation gas turbines projected for commercial applications after the year 2000 will contribute to another step change in technology. It is expected that the initial commercialization process will provide the basis for clear technology choices on future plants.

  19. SPEAR-BETA fuel-performance code system: fission-gas-release module. Final report

    International Nuclear Information System (INIS)

    Christensen, R.

    1983-03-01

    The original SPEAR-BETA general description manual covers both mechanistic and statistical models for fuel reliability, but only mechanistic modeling of fission gas release. This addendum covers the SPEAR-BETA statistical model for fission gas release

  20. Probabilistic consequence assessment of hydrogen sulphide releases from a heavy water plant

    International Nuclear Information System (INIS)

    Baynes, C.J.

    1986-05-01

    This report provides a summary of work carried out on behalf of the Atomic Energy Control Board, concerned with the consequences of accidental releases to the atmosphere of hydrogen sulphide (H 2 S) at a heavy water plant. In this study, assessments of consequences are made in terms of the probabilities of a range of possible outcomes, i.e., numbers of fatalities, given a certain release scenario. The report describes the major features of a computer model which was developed to calculate the consequences and their associated probabilities, and the major input data used in applying the model to a consequence assessment of the Bruce heavy water plant (HWP) in Ontario. The results of the sensitivity analyses of the model are summarized. Finally, the results of the consequence assessments of 43 accidental release scenarios at the Bruce HWP are summarized, together with a number of conclusions which were drawn from these results regarding the predicted consequences and the factors which influence them

  1. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    International Nuclear Information System (INIS)

    Barboza, N.O.

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of ∼17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, ∼200 g/cm 3 and ∼20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases ∼350 MJ of energy in optimized power plant scenarios

  2. CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Weberg, Micah J. [PhD Candidate in Space Science, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2134A Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Lepri, Susan T. [Associate Professor, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2429 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Zurbuchen, Thomas H., E-mail: mjweberg@umich.edu, E-mail: slepri@umich.edu, E-mail: thomasz@umich.edu [Professor, Space Science and Aerospace Engineering, Associate Dean for Entrepreneurship Senior Counselor of Entrepreneurship Education, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2431 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States)

    2015-03-10

    The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space.

  3. CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Weberg, Micah J.; Lepri, Susan T.; Zurbuchen, Thomas H.

    2015-01-01

    The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space

  4. Release to the gas phase of metals, S and Cl during combustion of dedicated waste fractions

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; van Lith, Simone Cornelia; Frandsen, Flemming

    2010-01-01

    The release to the gas phase of inorganic elements such as alkali metals. Cl, S, and heavy metals in Waste-to-Energy (WtE) boilers is a challenge. Besides the risk of harmful emissions to the environment, inorganic elements released from the grate may cause severe ash deposition and corrosion...... and the link to the formation of fly ash and aerosols in full-scale waste incinerators. The release of metals, S and Cl from four dedicated waste fractions was quantified as a function of temperature in a lab-scale fixed-bed reactor. The waste fractions comprised chromated copper arsenate (CCA) impregnated....... The lab-scale release results were then compared with results from a related, full-scale partitioning study, in which test runs with the addition of similar, dedicated waste fractions to a base-load waste had been performed in a grate-fired WtE boiler. In general, the elements Al, Ca, Cr, Cu, Fe, Mg, Si...

  5. Greenhouse Gas and Noxious Emissions from Dual Fuel Diesel and Natural Gas Heavy Goods Vehicles.

    Science.gov (United States)

    Stettler, Marc E J; Midgley, William J B; Swanson, Jacob J; Cebon, David; Boies, Adam M

    2016-02-16

    Dual fuel diesel and natural gas heavy goods vehicles (HGVs) operate on a combination of the two fuels simultaneously. By substituting diesel for natural gas, vehicle operators can benefit from reduced fuel costs and as natural gas has a lower CO2 intensity compared to diesel, dual fuel HGVs have the potential to reduce greenhouse gas (GHG) emissions from the freight sector. In this study, energy consumption, greenhouse gas and noxious emissions for five after-market dual fuel configurations of two vehicle platforms are compared relative to their diesel-only baseline values over transient and steady state testing. Over a transient cycle, CO2 emissions are reduced by up to 9%; however, methane (CH4) emissions due to incomplete combustion lead to CO2e emissions that are 50-127% higher than the equivalent diesel vehicle. Oxidation catalysts evaluated on the vehicles at steady state reduced CH4 emissions by at most 15% at exhaust gas temperatures representative of transient conditions. This study highlights that control of CH4 emissions and improved control of in-cylinder CH4 combustion are required to reduce total GHG emissions of dual fuel HGVs relative to diesel vehicles.

  6. Conceptual Design of Portable Filtered Air Suction Systems For Prevention of Released Radioactive Gas under Severe Accidents of NPP

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Beom W.; Choi, Su Y.; Yim, Man S.; Rim, Chun T. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    It becomes evident that severe accidents may occur by unexpected disasters such as tsunami, heavy flood, or terror. Once radioactive material is released from NPP through severe accidents, there are no ways to prevent the released radioactive gas spreading in the air. As a remedy for this problem, the idea on the portable filtered air suction system (PoFASS) for the prevention of released radioactive gas under severe accidents was proposed. In this paper, the conceptual design of a PoFASS focusing on the number of robot fingers and robot arm rods are proposed. In order to design a flexible robot suction nozzle, mathematical models for the gaps which represent the lifted heights of extensible covers for given convex shapes of pipes and for the covered areas are developed. In addition, the system requirements for the design of the robot arms of PoFASS are proposed, which determine the accessible range of leakage points of released radioactive gas. In this paper, the conceptual designs of the flexible robot suction nozzle and robot arm have been conducted. As a result, the minimum number of robot fingers and robot arm rods are defined to be four and three, respectively. For further works, extensible cover designs on the flexible robot suction nozzle and the application of the PoFASS to the inside of NPP should be studied because the radioactive gas may be released from connection pipes between the containment building and auxiliary buildings.

  7. FEBEX. Investigations on gas generation, release and migration

    International Nuclear Information System (INIS)

    Jockwer, Norbert; Wieczorek, Klaus

    2008-06-01

    The FEBEX project is based on the Spanish reference concept for the disposal of radioactive waste in crystalline rock, which considers the emplacement of the canisters enclosing the conditioned waste surrounded by clay barriers constructed of high-compacted bentonite blocks in horizontal drifts /ENR 957. The whole project consisted of an experimental and a modelling part. The experimental part itself was divided into the in-situ test, a mock-up test performed at the CIEMAT laboratory, and various small-scale laboratory tests. In the modelling part it was expected to develop and validate the thermo-hydro-mechanical (THM) and the thermo-hydro-chemical (THC) processes for the performance assessment of the near-field behaviour. GRS was only involved in the in-situ test and some additional laboratory work with regard to gas generation, gas migration, and pore pressure build-up in the buffer constructed of high-compacted bentonite blocks around the electrical heaters simulating the waste containers. The following topics are covered: installation and dismantling of the heater pipes; methods of gas generation and release measurement, summary of results and discussion

  8. Innovation of fission gas release and thermal conductivity measurement methods

    International Nuclear Information System (INIS)

    Van der Meer, K.; Soboler, V.

    1998-01-01

    This presentation described two innovative measurement methods being currently developed at SCK-CEN in order to support the modeling of fuel performance. The first one is an acoustic method to measure the fission gas release in a fuel rod in a non destructive way. The total rod pressure is determined by generating a heat pulse causing a pressure wave that propagates through the gas to an ultrasound transducer. The final pulse width being proportional to the pressure, the latter can thus be determined. The measurement of the acoustic resonance frequency at fixed temperatures enables the distinction between different gas components. The second method is a non-stationary technique to investigate the thermal properties of the fuel rod, like thermal conductivity, diffusivity and heat capacity. These properties are derived from the amplitude and the phase shift of the fuel centre temperature response induced by a periodic temperature variation. These methods did not reveal any physical limitations for the practical applicability. Furthermore, they are rather simple. Preliminary investigations have proven both methods to be more accurate than techniques usually utilized. (author)

  9. A new mechanistic and engineering fission gas release model for a uranium dioxide fuel

    International Nuclear Information System (INIS)

    Lee, Chan Bock; Yang, Yong Sik; Kim, Dae Ho; Kim, Sun Ki; Bang, Je Geun

    2008-01-01

    A mechanistic and engineering fission gas release model (MEGA) for uranium dioxide (UO 2 ) fuel was developed. It was based upon the diffusional release of fission gases from inside the grain to the grain boundary and the release of fission gases from the grain boundary to the external surface by the interconnection of the fission gas bubbles in the grain boundary. The capability of the MEGA model was validated by a comparison with the fission gas release data base and the sensitivity analyses of the parameters. It was found that the MEGA model correctly predicts the fission gas release in the broad range of fuel burnups up to 98 MWd/kgU. Especially, the enhancement of fission gas release in a high-burnup fuel, and the reduction of fission gas release at a high burnup by increasing the UO 2 grain size were found to be correctly predicted by the MEGA model without using any artificial factor. (author)

  10. Gas generation and release from the VLJ repository

    International Nuclear Information System (INIS)

    Vieno, T.; Valkiainen, M.

    1992-01-01

    The VLJ repository is an underground disposal facility located at the Olkiluoto nuclear power plant site on the west coast of Finland. The repository will house low (LLW) and intermediate level radioactive wastes (MLW) from the TVO I and TVO II BWR's and the spent fuel interim store at Olkiluoto. The disposal rooms have been excavated at a depth of 60... 100 meters in the crystalline bedrock. They consist of two rock silos - one for the LLW and the other for MLW. Low level waste is usually packed in steel drums and steel boxes. Medium level wastes consists of bituminized resins in steel drums. Wastes packages are emplaced in concrete boxes before transportation into the repository. Low level wastes are emplaced in the shotcreted rock silo where no backfilling will used. For medium level wastes, a separate silo of reinforced concrete has been constructed inside the rock silo. No backfilling will be used inside the concrete silo and an opening will be made in the lid of the concrete silo for gas release. The microbial degradation of low level wastes is the principle gas generation process in the repository. The gas transport though the bedrock covering the repository is evaluated with the help of ground water flow study. It is recommended that the shotcrete lining on the ceiling of the repository cavern is partly removed before the final sealing of the repository. Provided that dissipation of gases from the disposal cavern into the rock can been assured, the overall effects of gas generation on the long-term safety of the repository are insignificant. 10 refs., 6 figs

  11. Safety barriers to prevent release of hydrocarbons during production of oil and gas

    OpenAIRE

    Sklet, Snorre; Hauge, Stein

    2004-01-01

    This report documents a set of scenarios related to release of hydrocarbons during production on oil and gas platforms. For each release scenario, initiating events, barrier functions aimed to prevent loss of containment, and barrier systems that realize these barrier functions are identified and described. Safety barriers to prevent release of hydrocarbons during production of oil and gas

  12. Irradiation techniques for the release of bound heavy metals in natural waters and blood

    International Nuclear Information System (INIS)

    Batley, G.E.; Farrar, Y.J.

    1978-01-01

    Irradiation techniques are compared with conventional acid digestion procedures for the release of bound heavy metals in natural waters and in blood, before their determination by anodic stripping voltammetry. Ultra-violet irradiation of acidified water with a 550-W mercury vapour lamp releases bound zinc, cadmium, lead and copper after 4 h. The same results can be achieved with a 30 Mrad dose of high-energy γ-irradiation. These techniques are also effective for the release of metals in whole blood and blood plasma, where sample volumes as small as 200 μl are adequate in analyses for zinc, copper and lead. By comparison with acid digestion and solvent extraction methods, irradiation treatments offer the advantages of minimum sample manipulation and negligible reagent blanks. (Auth.)

  13. Local Fission Gas Release and Swelling in Water Reactor Fuel during Slow Power Transients

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Walker, C.T.; Ray, I.L.F.

    1985-01-01

    Gas release and fuel swelling caused by a power increase in a water reactor fuel (burn-up 2.7–4.5% FIMA) is described. At a bump terminal level of about 400 W/cm (local value) gas release was 25–40%. The formation of gas bubbles on grain boundaries and their degree of interlinkage are the two...... factors that determine the level of fission gas release during a power bump. Release begins when gas bubbles on grain boundaries start o interlink. This occurred at r/r0 ~ 0.75. Release tunnels were fully developed at r/r0 ~ 0.55 with the result that gas release was 60–70% at this position....

  14. Concentration fluctuations in gas releases by industrial accidents. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, M.; Chatwin, P.C.; Joergensen, H.E.; Mole, N.; Munro, R.J.; Ott, S.

    2002-05-01

    The COFIN project studied existing remote-sensing Lidar data on concentration fluctuations in atmospheric dispersion from continuous sources at ground level. Fluctuations are described by stochastic models developed by a combination of statistical analyses and surface-layer scaling. The statistical moments and probability density distribution of the fluctuations are most accurately determined in a frame of reference following the instantaneous plume centreline. The spatial distribution of these moments is universal with a gaussian core and exponential tails. The instantaneous plume width is fluctuating with a log-normal distribution. The position of the instantaneous plume centre-line is modelled by a normal distribution and a Langevin equation, by which the meander effect on the time-averaged plume width is predicted. Fixed-frame statistics are modelled by convolution of moving-frame statistics and the probability distribution for the plume centreline. The distance-neighbour function generalized for higher-order statistics has a universal exponential shape. Simulation tools for concentration fluctuations have been developed for either multiple correlated time series or multi-dimensional fields. These tools are based on Karhunen-Loeve expansion and Fourier transformations using iterative or correlation-distortion techniques. The input to the simulation is the probability distribution of the individual processes, assumed stationary, and the cross-correlations of all signal combinations. The use in practical risk assessment is illustrated by implementation of a typical heavy-gas dispersion model, enhanced for prediction and simulation of concentration fluctuations. (au)

  15. New Fokker-Planck derivation of heavy gas models for neutron thermalization

    International Nuclear Information System (INIS)

    Larsen, E.W.; Williams, M.M.R.

    1990-01-01

    This paper is concerned with the derivation of new generalized heavy gas models for the infinite medium neutron energy spectrum equation. Our approach is general and can be used to derive improved Fokker-Planck approximations for other types of kinetic equations. In this paper we obtain two distinct heavy gas models, together with estimates for the corresponding errors. The models are shown in a special case to reduce to modified heavy gas models proposed earlier by Corngold (1962). The error estimates show that both of the new models should be more accurate than Corngold's modified heavy gas model, and that the first of the two new models should generally be more accurate than the second. (author)

  16. Fission gas release from oxide fuels at high burnups (AWBA development program)

    International Nuclear Information System (INIS)

    Dollins, C.C.

    1981-02-01

    The steady state gas release, swelling and densification model previously developed for oxide fuels has been modified to accommodate the slow transients in temperature, temperature gradient, fission rate and pressure that are encountered in normal reactor operation. The gas release predictions made by the model were then compared to gas release data on LMFBR-EBRII fuels obtained by Dutt and Baker and reported by Meyer, Beyer, and Voglewede. Good agreement between the model and the data was found. A comparison between the model and three other sets of gas release data is also shown, again with good agreement

  17. Methods for natural gas and heavy hydrocarbon co-conversion

    Science.gov (United States)

    Kong, Peter C [Idaho Falls, ID; Nelson, Lee O [Idaho Falls, ID; Detering, Brent A [Idaho Falls, ID

    2009-02-24

    A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

  18. Gas retention and release behavior in Hanford double-shell waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, P.A.; Brewster, M.E.; Bryan, S.A. [and others

    1997-05-01

    This report describes the current understanding of flammable gas retention and release in Hanford double-shell waste tanks AN-103, AN-104, AN-105, AW-101, SY-101, and SY-103. This knowledge is based on analyses, experimental results, and observations of tank behavior. The applicable data available from the void fraction instrument, retained gas sampler, ball rheometer, tank characterization, and field monitoring are summarized. Retained gas volumes and void fractions are updated with these new data. Using the retained gas compositions from the retained gas sampler, peak dome pressures during a gas burn are calculated as a function of the fraction of retained gas hypothetically released instantaneously into the tank head space. Models and criteria are given for gas generation, initiation of buoyant displacement, and resulting gas release; and predictions are compared with observed tank behavior.

  19. Gas retention and release behavior in Hanford double-shell waste tanks

    International Nuclear Information System (INIS)

    Meyer, P.A.; Brewster, M.E.; Bryan, S.A.

    1997-05-01

    This report describes the current understanding of flammable gas retention and release in Hanford double-shell waste tanks AN-103, AN-104, AN-105, AW-101, SY-101, and SY-103. This knowledge is based on analyses, experimental results, and observations of tank behavior. The applicable data available from the void fraction instrument, retained gas sampler, ball rheometer, tank characterization, and field monitoring are summarized. Retained gas volumes and void fractions are updated with these new data. Using the retained gas compositions from the retained gas sampler, peak dome pressures during a gas burn are calculated as a function of the fraction of retained gas hypothetically released instantaneously into the tank head space. Models and criteria are given for gas generation, initiation of buoyant displacement, and resulting gas release; and predictions are compared with observed tank behavior

  20. Calculation of burnup and power dependence on fission gas released from PWR type reactor fuel element

    International Nuclear Information System (INIS)

    Edy-Sulistyono

    1996-01-01

    Burn up dependence of fission gas released and variation power analysis have been conducted using FEMXI-IV computer code program for Pressure Water Reactor Fuel During steady-state condition. The analysis result shows that the fission gas release is sensitive to the fuel temperature, the increasing of burn up and power in the fuel element under irradiation experiment

  1. Stoichiometric and lean burn heavy-duty gas engines: a dilemma between emissions and fuel consumption?

    NARCIS (Netherlands)

    Steen, M. van der; Rijke, J. de; Seppen, J.J.

    1996-01-01

    This paper compares stoichiometric with lean burn technology for heavy-duty gas engines (natural gas and LPG) and demonstrates that there is a future for both engine concepts on the multilateral global market. Emission limits in Europe as expected in the near future will facilitate both engine

  2. Beer self-administration provokes lateralized nucleus accumbens dopamine release in male heavy drinkers.

    Science.gov (United States)

    Oberlin, Brandon G; Dzemidzic, Mario; Tran, Stella M; Soeurt, Christina M; O'Connor, Sean J; Yoder, Karmen K; Kareken, David A

    2015-03-01

    Although striatal dopamine (DA) is important in alcohol abuse, the nature of DA release during actual alcohol drinking is unclear, since drinking includes self-administration of both conditioned flavor stimuli (CS) of the alcoholic beverage and subsequent intoxication, the unconditioned stimulus (US). Here, we used a novel self-administration analog to distinguish nucleus accumbens (NAcc) DA responses specific to the CS and US. Right-handed male heavy drinkers (n = 26) received three positron emission tomography (PET) scans with the D2/D3 radioligand [(11)C]raclopride (RAC) and performed a pseudo self-administration task that separately administered a flavor CS of either a habitually consumed beer or the appetitive control Gatorade®, concomitant with the US of ethanol intoxication (0.06 g/dL intravenous (IV) administration) or IV saline. Scan conditions were Gatorade flavor + saline (Gat&Sal), Gatorade flavor + ethanol (Gat&Eth), and beer flavor + ethanol (Beer&Eth). Ethanol (US) reduced RAC binding (inferring DA release) in the left (L) NAcc [Gat&Sal > Gat&Eth]. Beer flavor (CS) increased DA in the right (R) NAcc [Gat&Eth > Beer&Eth]. The combination of beer flavor and ethanol (CS + US), [Gat&Sal > Beer&Eth], induced DA release in bilateral NAcc. Self-reported intoxication during scanning correlated with L NAcc DA release. Relative to saline, infusion of ethanol increased alcoholic drink wanting. Our findings suggest lateralized DA function in the NAcc, with L NAcc DA release most reflecting intoxication, R NAcc DA release most reflecting the flavor CS, and the conjoint CS + US producing a bilateral NAcc response.

  3. Study of new structures adapted to gas-graphite and gas-heavy water reactors

    International Nuclear Information System (INIS)

    Martin, R.; Roche, R.

    1964-01-01

    The experience acquired as a result of the operation of the Marcoule reactors and of the construction and start-up of the E.D.F. reactors on the one hand, and the conclusions of research and tests carried out out-of-pile on the other hand, lead to a considerable change in the general design of reactors of the gas-graphite type. The main modifications envisaged are analysed in the paper. The adoption of an annular fuel element and of a down-current cooling will make it possible to increase considerably the specific power and the power output of each channel; as a result there will be a considerable reduction in the number of the channels and a corresponding increase in the size of the unit cell. The graphite stack will have to be adapted to there new conditions. For security reasons, the use of prestressed concrete for the construction of the reactor vessel is becoming more widespread; they could lead to the exchangers and the fuel-handling apparatus becoming integrated inside the vessel (the so-called 'attic' device). A full-size mode) of this attic has been built at Saclay with the participation of EURATOM; the operational results obtained are presented as well as a new original design for the control rods. As for as the gas-heavy-water system is concerned, the research is carried out on two points of design; the first, which retains the use of horizontal pressure tubes, takes into account the experience acquired during the construction of the EL 4 reactor of which it will constitute an extrapolation; the second, arising from the research carried out on the gas-graphite system, will use a pre-stressed concrete vessel for holding the pressure, the moderator being almost at the same pressure as the cooling fluid and the fuel being placed in vertical channels. The relative merits of these two variants are analysed in the present paper. (authors) [fr

  4. Specialists' meeting on fission product release and transport in gas-cooled reactors. Summary report

    International Nuclear Information System (INIS)

    1985-01-01

    The purpose of the Meeting on Fission Product Release and Transport in Gas-Cooled Reactors was to compare and discuss experimental and theoretical results of fission product behaviour in gas-cooled reactors under normal and accidental conditions and to give direction for future development. The technical part of the meeting covered operational experience and laboratory research, activity release, and behaviour of released activity

  5. Specialists' meeting on fission product release and transport in gas-cooled reactors. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1985-07-01

    The purpose of the Meeting on Fission Product Release and Transport in Gas-Cooled Reactors was to compare and discuss experimental and theoretical results of fission product behaviour in gas-cooled reactors under normal and accidental conditions and to give direction for future development. The technical part of the meeting covered operational experience and laboratory research, activity release, and behaviour of released activity.

  6. Effect of gas release in hot molding on flexural strength of composite friction brake

    Science.gov (United States)

    Rusdja, Andy Permana; Surojo, Eko; Muhayat, Nurul; Raharjo, Wijang Wisnu

    2018-02-01

    Composite friction brake is a vital part of braking system which serves to reduce the speed of vehicle. To fulfill the requirement of brake performance, composite friction brake must have friction and mechanical characteristic as required. The characteristics of composite friction brake are affected by brake material formulation and manufacturing parameter. In the beginning of hot molding, intermittent hot pressing was carried out to release the gases that consist of ammonia gas and water vapor. In composite friction brake, phenolic resin containing hexamethylenetetramine (HMTA) is often used as a binder. During hot molding, the reaction of phenolic resin and HMTA forms ammonia gas. Hot molding also generates water vapor because raw materials absorb moisture from environment when they are placed in storage. The gas release in hot molding is supposed affecting mechanical properties because it avoid entrapped gas in composite, so that this research investigated effect of gas release on flexural strength. Manufacturing of composite specimen was carried out as follow: mixing of raw materials, cold molding, and hot molding. In this research, duration of intermittent hot pressing and number of gas release were varied. The flexural strength of specimen was measured using three point bending test. The results showed that flexural strength specimens that were manufactured without gas release, using 4 times gas release with intermittent hot pressing for 5 and 10 seconds were not remarkably different. Conversely, hot molding using 4 times gas release with intermittent hot pressing for 15 seconds decreased flexural strength of composite. Hot molding using 2, 4, and 8 times gas release with intermittent hot pressing for 10 seconds also had no effect on increasing flexural strength. Increasing of flexural strength of composite was obtained only by using 6 times gas release with intermittent hot pressing for 10 seconds.

  7. Gas retention and release behavior in Hanford single-shell waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

    1996-12-01

    This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large ({approximately}100 m{sup 3}) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given.

  8. Gas retention and release behavior in Hanford single-shell waste tanks

    International Nuclear Information System (INIS)

    Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

    1996-12-01

    This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large (∼100 m 3 ) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given

  9. Fission gas release and pellet microstructure change of high burnup BWR fuel

    International Nuclear Information System (INIS)

    Itagaki, N.; Ohira, K.; Tsuda, K.; Fischer, G.; Ota, T.

    1998-01-01

    UO 2 fuel, with and without Gadolinium, irradiated for three, five, and six irradiation cycles up to about 60 GWd/t pellet burnup in a commercial BWR were studied. The fission gas release and the rim effect were investigated by the puncture test and gas analysis method, OM (optical microscope), SEM (scanning electron microscope), and EPMA (electron probe microanalyzer). The fission gas release rate of the fuel rods irradiated up to six cycles was below a few percent; there was no tendency for the fission gas release to increase abruptly with burnup. On the other hand, microstructure changes were revealed by OM and SEM examination at the rim position with burnup increase. Fission gas was found depleted at both the rim position and the pellet center region using EPMA. There was no correlation between the fission gas release measured by the puncture test and the fission gas depletion at the rim position using EPMA. However, the depletion of fission gas in the center region had good correlation with the fission gas release rate determined by the puncture test. In addition, because the burnup is very large at the rim position of high burnup fuel and also due to the fission rate of the produced Pu, the Xe/Kr ratio at the rim position of high burnup fuel is close to the value of the fission yield of Pu. The Xe/Kr ratio determined by the gas analysis after the puncture test was equivalent to the fuel average but not to the pellet rim position. From the results, it was concluded that fission gas at the rim position was released from the UO 2 matrix in high burnup, however, most of this released fission gas was held in the porous structure and not released from the pellet to the free volume. (author)

  10. An approach for estimating toxic releases of H{sub 2}S-containing natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Jianwen, Zhang, E-mail: zhangjw@mail.buct.edu.cn [Lab of Fluid Flow and Heat Transfer, Beijing University of Chemical Technology, Beijing 100029 (China); Institute of Safety Management, Beijing University of Chemical Technology, Beijing 100029 (China); Da, Lei [Lab of Fluid Flow and Heat Transfer, Beijing University of Chemical Technology, Beijing 100029 (China); College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wenxing, Feng [Pipeline Research Center of PetroChina Company Lmited, 51 Golden Road, Langfang 065000 (China)

    2014-01-15

    Highlights: • Behavior of H{sub 2}S-containing natural gas exhibits appearance of neutral gas by CFD. • The poisoning hazards of H{sub 2}S by gas pipeline releases are successfully estimated. • An assessment method for available safe egress time is proposed. -- Abstract: China is well known being rich in sulfurous natural gas with huge deposits widely distributed all over the country. Due to the toxic nature, the release of hydrogen sulfide-containing natural gas from the pipelines intends to impose serious threats to the human, society and environment around the release sources. CFD algorithm is adopted to simulate the dispersion process of gas, and the results prove that Gaussian plume model is suitable for determining the affected region of the well blowout of sulfide hydrogen-containing natural gas. In accordance with the analysis of release scenarios, the present study proposes a new approach for estimating the risk of hydrogen sulfide poisoning hazards, as caused by sulfide-hydrogen-containing natural gas releases. Historical accident-statistical data from the EGIG (European Gas Pipeline Incident Data Group) and the Britain Gas Transco are integrated into the approach. Also, the dose-load effect is introduced to exploit the hazards’ effects by two essential parameters – toxic concentration and exposure time. The approach was applied to three release scenarios occurring on the East-Sichuan Gas Transportation Project, and the individual risk and societal risk are classified and discussed. Results show that societal risk varies significantly with different factors, including population density, distance from pipeline, operating conditions and so on. Concerning the dispersion process of hazardous gas, available safe egress time was studied from the perspective of individual fatality risks. The present approach can provide reliable support for the safety management and maintenance of natural gas pipelines as well as evacuations that may occur after

  11. Steady-state and transient fission gas release and swelling model for LIFE-4

    International Nuclear Information System (INIS)

    Villalobos, A.; Liu, Y.Y.; Rest, J.

    1984-06-01

    The fuel-pin modeling code LIFE-4 and the mechanistic fission gas behavior model FASTGRASS have been coupled and verified against gas release data from mixed-oxide fuels which were transient tested in the TREAT reactor. Design of the interface between LIFE-4 and FASTGRASS is based on an earlier coupling between an LWR version of LIFE and the GRASS-SST code. Fission gas behavior can significantly affect steady-state and transient fuel performance. FASTGRASS treats fission gas release and swelling in an internally consistent manner and simultaneously includes all major mechanisms thought to influence fission gas behavior. The FASTGRASS steady-state and transient analysis has evolved through comparisons of code predictions with fission-gas release and swelling data from both in- and ex-reactor experiments. FASTGRASS was chosen over other fission-gas behavior models because of its availability, its compatibility with the LIFE-4 calculational framework, and its predictive capability

  12. Simulation experiments on the radial pool growth in gas-releasing melting system

    International Nuclear Information System (INIS)

    Farhadieh, R.; Purviance, R.; Carlson, N.

    1983-01-01

    Following an HCDA, molten core-debris can contact the concrete foundation of the reactor building resulting in a molten UO 2 /concrete interaction and considerable gas release. The released gas can pressurize the containment building potentially leading to radiological releases. Furthermore, directional growth of the molten core-debris pool can reduce the reactor building structural integrity. To implement design changes that insure structural integrity, an understanding of the thermal-hydraulic and mass-transfer process associated with such a growth is most desirable. Owing to the complex nature of the combined heat, mass, and hydrodynamic processes associated with the two-dimensional problem of gas release and melting, the downward and radial penetration problems have been investigated separately. The present experimental study addresses the question of sideward penetration of the molten core debris into a gas-releasing, meltable, miscible solid

  13. Method for removing heavy metal and nitrogen oxides from flue gas, device for removing heavy metal and nitrogen oxides from flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hann-Sheng; Livengood, Charles David

    1997-12-01

    A method for the simultaneous removal of oxides and heavy metals from a fluid is provided comprising combining the fluid with compounds containing alkali and sulfur to create a mixture; spray drying the mixture to create a vapor phase and a solid phase; and isolating the vapor phase from the solid phase. A device is also provided comprising a means for spray-drying flue gas with alkali-sulfide containing liquor at a temperature sufficient to cause the flue gas to react with the compounds so as to create a gaseous fraction and a solid fraction and a means for directing the gaseous fraction to a fabric filter.

  14. Production and release of the fission gas in (Th U)O2 fuel rods

    International Nuclear Information System (INIS)

    Dias, Marcio S.

    1982-06-01

    The volume, composition and release of the fission gas products were caculated for (Th, U)O 2 fuel rods. The theorectical calculations were compared with experimental results available on the literature. In ThO 2 + 5% UO 2 fuel rods it will be produced approximated 5% more fission gas as compared to UO 2 fuel rods. The fission gas composition or Xe to Kr ratio has showed a decreasing fuel brunup dependence, in opposition to that of UO 2 . Under the same fuel rod operational conditions, the (Th, U)O 2 fission gas release will be smaller as compared to UO 2 . This behaviour of (Th, U)O 2 fuel comes from smallest gas atom difusivity and higher activation energies of the processes that increase the fission gas release. (Author) [pt

  15. Fission gas release at high burn-up: beyond the standard diffusion model

    International Nuclear Information System (INIS)

    Landskron, H.; Sontheimer, F.; Billaux, M.R.

    2002-01-01

    At high burn-up standard diffusion models describing the release of fission gases from nuclear fuel must be extended to describe the experimental loss of xenon observed in the fuel matrix of the rim zone. Marked improvements of the prediction of integral fission gas release of fuel rods as well as of radial fission gas profiles in fuel pellets are achieved by using a saturation concept to describe fission gas behaviour not only in the pellet rim but also as an additional fission gas path in the whole pellet. (author)

  16. Refining fuels of the heavy gas--oil type

    Energy Technology Data Exchange (ETDEWEB)

    Bruzac, J F.A.

    1930-01-28

    This invention has for its object the production of a new type of gas-oil fuel, obtained from crude petroleum, shale oil, and peat oil, according to the method of treatment mentioned, by means of which is obtained from gas oil, shale oil, lignite oil, and peat oil (deprived of asphaltic, and bituminous, resinous, and sulfur compounds), a fuel suitable for running Diesel, Junkers, and Clerget motors and all others of the same kind, by diminishing considerably the fouling and attack on the metal.

  17. A Discussion of SY-101 Crust Gas Retention and Release Mechanisms

    International Nuclear Information System (INIS)

    Mendoza, D.P.; Mahoney, L.A.; Gauglitz, P.A.; Rassat, S.D.; Caley, S.M.

    1999-01-01

    The flammable gas hazard in Hanford waste tanks was made an issue by the behavior of double-shell Tank (DST) 241-SY-101 (SY-101). Shortly after SY-101 was filled in 1980, the waste level began rising periodically, due to the generation and retention of gases within the slurry, and then suddenly dropping as the gases were released. An intensive study of the tank's behavior revealed that these episodic releases posed a safety hazard because the released gas was flammable, and, in some cases, the volume of gas released was sufficient to exceed the lower flammability limit (LFL) in the tank headspace (Alleinann et al. 1993). A mixer pump was installed in SY-101 in late 1993 to prevent gases from building up in the settled solids layer, and the large episodic gas releases have since ceased (Allemann et al. 1994; Stewart et al. 1994; Brewster et al. 1995). However, the surface level of SY-101 has been increasing since at least 1995, and in recent months the level growth has shown significant and unexpected acceleration. Based on a number of observations and measurements, including data from the void fraction instrument (VFI), we have concluded that the level growth is caused largely by increased gas retention in the floating crust. In September 1998, the crust contained between about 21 and 43% void based on VFI measurements (Stewart et al. 1998). Accordingly, it is important to understand the dominant mechanisms of gas retention, why the gas retention is increasing, and whether the accelerating level increase will continue, diminish or even reverse. It is expected that the retained gas in the crust is flammable, with hydrogen as a major constituent. This gas inventory would pose a flammable gas hazard if it were to release suddenly. In May 1997, the mechanisms of bubble retention and release from crust material were the subject of a workshop. The evaluation of the crust and potential hazards assumed a more typical void of roughly 15% gas. It could be similar to

  18. A Discussion of SY-101 Crust Gas Retention and Release Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    SD Rassat; PA Gauglitz; SM Caley; LA Mahoney; DP Mendoza

    1999-02-23

    The flammable gas hazard in Hanford waste tanks was made an issue by the behavior of double-shell Tank (DST) 241-SY-101 (SY-101). Shortly after SY-101 was filled in 1980, the waste level began rising periodically, due to the generation and retention of gases within the slurry, and then suddenly dropping as the gases were released. An intensive study of the tank's behavior revealed that these episodic releases posed a safety hazard because the released gas was flammable, and, in some cases, the volume of gas released was sufficient to exceed the lower flammability limit (LFL) in the tank headspace (Allemann et al. 1993). A mixer pump was installed in SY-101 in late 1993 to prevent gases from building up in the settled solids layer, and the large episodic gas releases have since ceased (Allemann et al. 1994; Stewart et al. 1994; Brewster et al. 1995). However, the surface level of SY-101 has been increasing since at least 1995, and in recent months the level growth has shown significant and unexpected acceleration. Based on a number of observations and measurements, including data from the void fraction instrument (VFI), we have concluded that the level growth is caused largely by increased gas retention in the floating crust. In September 1998, the crust contained between about 21 and 43% void based on VFI measurements (Stewart et al. 1998). Accordingly, it is important to understand the dominant mechanisms of gas retention, why the gas retention is increasing, and whether the accelerating level increase will continue, diminish or even reverse. It is expected that the retained gas in the crust is flammable, with hydrogen as a major constituent. This gas inventory would pose a flammable gas hazard if it were to release suddenly. In May 1997, the mechanisms of bubble retention and release from crust material were the subject of a workshop. The evaluation of the crust and potential hazards assumed a more typical void of roughly 15% gas. It could be similar to

  19. Implantation damage in heavy gas implanted 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Nicolaï, J., E-mail: julien.nicolai@univ-poitiers.fr [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Declémy, A. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Gilabert, E. [Centre d’Etude Nucléaire de Bordeaux-Gradignan, 33175 Gradignan Cedex (France); Beaufort, M.-F.; Barbot, J.-F. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France)

    2016-05-01

    Single crystals of SiC were implanted with heavy inert gases (Xe, Ar) at elevated temperatures (300–800 °C) and for a large range of fluence (1 × 10{sup 12}–1 × 10{sup 15} ions cm{sup −2}). Thermodesorption measurements suggest that gas is trapped by implantation-induced vacancy-type defects impeding any gas diffusion. The damage accumulation versus dose was studied through the tensile elastic strain determined by using X-ray diffraction. Results show that at low dose the strain is predictable via a thermally activated direct impact model. The low thermal activation energy at saturation suggests a dynamic recovery process dominated by the migration of interstitial-type defects as its relaxation during post thermal annealing. As compared with light-gas implantation the heavy-gas to defect ratio is low enhancing the formation of strongly perturbed zones rather than the formation of bubble precursors.

  20. Fission gas release and grain growth in THO2-UO2 fuel irradiated at high temperature

    International Nuclear Information System (INIS)

    Goldberg, I.; Waldman, L.A.; Giovengo, J.F.; Campbell, W.R.

    1979-01-01

    Data are presented on fission gas release and grain growth in ThO 2 -UO 2 fuels irradiated as part of the LWBR fuel element development program. These data for rods that experienced peak linear power outputs ranging from 15 to 22 KW/ft supplement fission gas release data previously reported for 51 rods containing ThO 2 and ThO 2 -UO 2 fuel irradiated at peak linear powers predominantly below 14 KW/ft. Fission gas release was relatively high (up to 15.0 percent) for the rods operated at high power in contrast to the relatively low fission gas release (0.1 to 5.2 percent) measured for the rods operated at lower power. Metallographic examination revealed extensive equiaxed grain growth in the fuel at the high power axial locations of the three rods

  1. Utilization of ''CONTACT'' experiments to improve the fission gas release knowledge in PWR fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Charles, M; Abassin, J J; Bruet, M; Baron, D; Melin, P

    1983-03-01

    The CONTACT experiments, which were carried out by the French CEA, within the framework of a CEA-FRAMATOME collaboration agreement, bear on the behaviour of in-pile irradiated PWR fuel rods. We will focus here upon their results dealing with fission gas release. The experimental device is briefly described, then the following results are given: the kinetics of stable fission gas release for various linear ratings; the instantaneous fractional release rates of radioactive gases versus their decay constant in the range 1.5 10/sup -6/-3.6 10/sup -3/s/sup -1/, for various burnups, as also the influence of fuel temperature. Moreover, the influence of the nature and the pressure of the filling gas upon the release is presented for various linear ratings. The experimental results are discussed and analysed with the purpose to model various physical phenomena involved in the release (low-temperature mechanisms, diffusion).

  2. In-pile observation of gas release from sodium-joint carbide pins irradiated in Osiris

    International Nuclear Information System (INIS)

    Colin, M.; Faugere, J.L.; Rouault, J.

    1978-01-01

    Gas release is studied in three sodium-joint carbide pins irradiated in the reactor Osiris at a nominal linear power of 900 W/cm to burn-ups ranging from 4 to 13%. The overall activity, stable gases and radioactive gases are measured. It is found that most of the gas is released in busts, that the release of stable gases speeds up sharply after an incubation time, that the initial bursts are very large and that for each mode of release observed and for each class of nuclide the radioactive gases follow a law R/B=A/lambda.n. An attempt is made to interpret the results in terms of either the formation of gas bubbles in the sodium joint, the existence of a large bubble above the fissile column or the simultaneous release of a large number of smaller bubbles [fr

  3. Utilization of ''CONTACT'' experiments to improve the fission gas release knowledge in PWR fuel rods

    International Nuclear Information System (INIS)

    Charles, M.; Abassin, J.J.; Bruet, M.

    1983-01-01

    The CONTACT experiments, which were carried out by the French CEA, within the framework of a CEA-FRAMATOME collaboration agreement, bear on the behaviour of in-pile irradiated PWR fuel rods. We will focus here upon their results dealing with fission gas release. The experimental device is briefly described, then the following results are given: the kinetics of stable fission gas release for various linear ratings; the instantaneous fractional release rates of radioactive gases versus their decay constant in the range 1.5 10 -6 -3.6 10 -3 s -1 , for various burnups, as also the influence of fuel temperature. Moreover, the influence of the nature and the pressure of the filling gas upon the release is presented for various linear ratings. The experimental results are discussed and analysed with the purpose to model various physical phenomena involved in the release (low-temperature mechanisms, diffusion)

  4. Mechanistic analysis of double-shell tank gas release

    Energy Technology Data Exchange (ETDEWEB)

    Allemann, R.T.; Antoniak, Z.I.; Friley, J.R.; Haines, C.E.; Liljegren, L.M.; Somasundaram, S.

    1991-12-01

    Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodically releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.

  5. Degassing, gas retention and release in Fe(0) permeable reactive barriers.

    Science.gov (United States)

    Ruhl, Aki S; Jekel, Martin

    2014-04-01

    Corrosion of Fe(0) has been successfully utilized for the reductive treatment of multiple contaminants. Under anaerobic conditions, concurrent corrosion leads to the generation of hydrogen and its liberation as a gas. Gas bubbles are mobile or trapped within the irregular pore structure leading to a reduction of the water filled pore volume and thus decreased residence time and permeability (gas clogging). With regard to the contaminant transport to the reactive site, the estimation of surface properties of the reactive material indicated that individual gas bubbles only occupied minor contact areas of the reactive surface. Quantification of gas entrapment by both gravimetrical and tracer investigations revealed that development of preferential flow paths was not significant. A novel continuous gravimetrical method was implemented to record variations in gas entrapment and gas bubble releases from the reactive filling. Variation of grain size fractions revealed that the pore geometry had a significant impact on gas release. Large pores led to the release of comparably large gas amounts while smaller volumes were released from finer pores with a higher frequency. Relevant processes are explained with a simplified pictorial sequence that incorporates relevant mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Delignification and Enhanced Gas Release from Soil Containing Lignocellulose by Treatment with Bacterial Lignin Degraders.

    Science.gov (United States)

    Rashid, Goran M M; Duran-Pena, Maria Jesus; Rahmanpour, Rahman; Sapsford, Devin; Bugg, Timothy D H

    2017-04-10

    The aim of the study was to isolate bacterial lignin-degrading bacteria from municipal solid waste soil, and to investigate whether they could be used to delignify lignocellulose-containing soil, and enhance methane release. A set of 20 bacterial lignin degraders, including 11 new isolates from municipal solid waste soil, were tested for delignification and phenol release in soil containing 1% pine lignocellulose. A group of 7 strains were then tested for enhancement of gas release from soil containing 1% lignocellulose in small-scale column tests. Using an aerobic pre-treatment, aerobic strains such as Pseudomonas putida showed enhanced gas release from the treated sample, but four bacterial isolates showed 5-10 fold enhancement in gas release in an in situ experiment under microanaerobic conditions: Agrobacterium sp., Lysinibacillus sphaericus, Comamonas testosteroni, and Enterobacter sp.. The results show that facultative anaerobic bacterial lignin degraders found in landfill soil can be used for in situ delignification and enhanced gas release in soil containing lignocellulose. The study demonstrates the feasibility of using an in situ bacterial treatment to enhance gas release and resource recovery from landfill soil containing lignocellulosic waste. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Treatment of Women With an Endometrial Polyp and Heavy Menstrual Bleeding: A Levonorgestrel-Releasing Intrauterine Device or Hysteroscopic Polypectomy?

    NARCIS (Netherlands)

    van Dijk, Myrthe M.; van Hanegem, Nehalennia; de Lange, Maria E.; Timmermans, Anne

    2015-01-01

    We performed a literature review of reports comparing a levonorgestrel-releasing intrauterine device (LNG-IUD) with transcervical polyp resection (TCRP) as a treatment for heavy menstrual bleeding (HMB). Our second objective was to investigate the effectiveness of LNG-IUD and TCRP in reducing

  8. An approach for estimating toxic releases of H2S-containing natural gas.

    Science.gov (United States)

    Jianwen, Zhang; Da, Lei; Wenxing, Feng

    2014-01-15

    China is well known being rich in sulfurous natural gas with huge deposits widely distributed all over the country. Due to the toxic nature, the release of hydrogen sulfide-containing natural gas from the pipelines intends to impose serious threats to the human, society and environment around the release sources. CFD algorithm is adopted to simulate the dispersion process of gas, and the results prove that Gaussian plume model is suitable for determining the affected region of the well blowout of sulfide hydrogen-containing natural gas. In accordance with the analysis of release scenarios, the present study proposes a new approach for estimating the risk of hydrogen sulfide poisoning hazards, as caused by sulfide-hydrogen-containing natural gas releases. Historical accident-statistical data from the EGIG (European Gas Pipeline Incident Data Group) and the Britain Gas Transco are integrated into the approach. Also, the dose-load effect is introduced to exploit the hazards' effects by two essential parameters - toxic concentration and exposure time. The approach was applied to three release scenarios occurring on the East-Sichuan Gas Transportation Project, and the individual risk and societal risk are classified and discussed. Results show that societal risk varies significantly with different factors, including population density, distance from pipeline, operating conditions and so on. Concerning the dispersion process of hazardous gas, available safe egress time was studied from the perspective of individual fatality risks. The present approach can provide reliable support for the safety management and maintenance of natural gas pipelines as well as evacuations that may occur after release incidents. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Gas chromatography/sniffing port analysis evaluated for aroma release from rehydrated French beans (Phaseolus vulgaris).

    NARCIS (Netherlands)

    Ruth, van S.M.; Roozen, J.P.; Cozijnsen, J.L.

    1996-01-01

    The technique of gas chromatography/sniffing port analysis was evaluated for studying the release of aroma compounds from rehydrated diced French beans. The aroma compounds 2-—methylbutanal and hexanal were released at a constant rate over time. An identical selection of odour active compounds was

  10. Do medium heavy fragments give evidence for a liquid-gas phase transition

    International Nuclear Information System (INIS)

    Trockel, R.; Hildenbrand, K.D.; Lynen, U.; Mueller, W.F.J.; Rabe, H.J.; Sann, H.; Stelzer, H.; Wada, R.; Brummund, N.; Glasow, R.; Kampert, K.H.; Santo, R.; Pelte, D.; Pochodzalla, J.; Eckert, E.

    1985-09-01

    Light and medium heavy fragments have been measured in light ion induced reactions at intermediate energies. The energy spectra have been parametrized with moving source fits. The resulting temperatures and yields do not confirm the expectations of a liquid-gas phase transition. (orig.)

  11. Recommended Ideal-Gas Thermochemical Functions for Heavy Water and its Substituent Isotopologues

    Czech Academy of Sciences Publication Activity Database

    Simkó, I.; Furtenbacher, T.; Hrubý, Jan; Zobov, N. F.; Polyansky, O. L.; Tennyson, J.; Gamache, R. R.; Szidarovszky, T.; Dénes, N.; Császár, A. G.

    2017-01-01

    Roč. 46, č. 2 (2017), č. článku 023104. ISSN 0047-2689 R&D Projects: GA ČR GA16-02647S Institutional support: RVO:61388998 Keywords : heavy water * ideal-gas thermochemical functions * partition function Subject RIV: BJ - Thermodynamics OBOR OECD: Thermodynamics Impact factor: 4.204, year: 2016

  12. Environmental risks due to radionuclide releases Environmental Risks Due To Radionuclide Releases From The Oil And Gas Industry

    International Nuclear Information System (INIS)

    Steinhausler, F.

    2005-01-01

    Full text : Exploration and transport in the oil- and gas industry result in the release of elevated levels of natural radioactivity into the environment. This has the following impact: Due to the large volumes of water needed during the extraction of gas and oil the resulting waste water can contain increased concentration of natural radionuclides, such as radium (Ra 226) and its decay products; At the oil/water interface waste water and sludge precipitate and form scalings, containing elevated levels of radium (Ra 226); At oil- and gas extraction sites tanks and equipment can be coated with long-lived radon (Rn 222) decay products; Along oil- and gas pipelines (e.g., at compressor stations) radon (Rn 222) decay products can be deposited internally on metal surfaces, such as valves. Typical U 238-series concentration values in production water range from 8 to 42 kBq/ m3, respectively in scale from 1 to 1 000 kBq/kg. In addition, oil- and gas extraction results in significant releases of natural radionuclides to the atmosphere (Rn 222) and to the water (Th 228, Ra 226, Rn 222, Pb 210, Po 210); for example, about 0.15 GBq/a of Rn 222 are released to the atmosphere per 106 m3 of oil extracted. The disposal of large amounts of contaminated wastes (scales, sludges) represents an environmental problem for the scrap metal industry (recycling of steel pipes containing scales) and the housing industry (use of sludge for landfill below a residential area). Using data from the oil- and gas industry in Latin America, Europe and the Asia-Pacific region, the various exposure pathways are reviewed. Furthermore, the current efforts in defining a suitable regulatory framework are discussed

  13. Utilizing natural gas huff and puff to enhance production in heavy oil reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Wenlong, G.; Shuhong, W.; Jian, Z.; Xialin, Z. [Society of Petroleum Engineers, Kuala Lumpur (Malaysia)]|[PetroChina Co. Ltd., Beijing (China); Jinzhong, L.; Xiao, M. [China Univ. of Petroleum, Beijing (China)

    2008-10-15

    The L Block in the north structural belt of China's Tuha Basin is a super deep heavy oil reservoir. The gas to oil ratio (GOR) is 12 m{sup 3}/m{sup 3} and the initial bubble point pressure is only 4 MPa. The low production can be attributed to high oil viscosity and low flowability. Although steam injection is the most widely method for heavy oil production in China, it is not suitable for the L Block because of its depth. This paper reviewed pilot tests in which the natural gas huff and puff process was used to enhance production in the L Block. Laboratory experiments that included both conventional and unconventional PVT were conducted to determine the physical property of heavy oil saturated by natural gas. The experiments revealed that the heavy oil can entrap the gas for more than several hours because of its high viscosity. A pseudo bubble point pressure exists much lower than the bubble point pressure in manmade foamy oils, which is relative to the depressurization rate. Elastic energy could be maintained in a wider pressure scope than natural depletion without gas injection. A special experimental apparatus that can stimulate the process of gas huff and puff in the reservoir was also introduced. The foamy oil could be seen during the huff and puff experiment. Most of the oil flowed to the producer in a pseudo single phase, which is among the most important mechanisms for enhancing production. A pilot test of a single well demonstrated that the oil production increased from 1 to 2 cubic metres per day to 5 to 6 cubic metres per day via the natural gas huff and puff process. The stable production period which was 5 to 10 days prior to huff and puff, was prolonged to 91 days in the first cycle and 245 days in the second cycle. 10 refs., 1 tab., 12 figs.

  14. Advancing Knowledge on Fugitive Natural Gas from Energy Resource Development at a Controlled Release Field Observatory

    Science.gov (United States)

    Cahill, A. G.; Chao, J.; Forde, O.; Prystupa, E.; Mayer, K. U.; Black, T. A.; Tannant, D. D.; Crowe, S.; Hallam, S.; Mayer, B.; Lauer, R. M.; van Geloven, C.; Welch, L. A.; Salas, C.; Levson, V.; Risk, D. A.; Beckie, R. D.

    2017-12-01

    Fugitive gas, comprised primarily of methane, can be unintentionally released from upstream oil and gas development either at surface from leaky infrastructure or in the subsurface through failure of energy well bore integrity. For the latter, defective cement seals around energy well casings may permit buoyant flow of natural gas from the deeper subsurface towards shallow aquifers, the ground surface and potentially into the atmosphere. Concerns associated with fugitive gas release at surface and in the subsurface include contributions to greenhouse gas emissions, subsurface migration leading to accumulation in nearby infrastructure and impacts to groundwater quality. Current knowledge of the extent of fugitive gas leakage including how to best detect and monitor over time, and particularly its migration and fate in the subsurface, is incomplete. We have established an experimental field observatory for evaluating fugitive gas leakage in an area of historic and ongoing hydrocarbon resource development within the Montney Resource Play of the Western Canadian Sedimentary Basin, British Columbia, Canada. Natural gas will be intentionally released at surface and up to 25 m below surface at various rates and durations. Resulting migration patterns and impacts will be evaluated through examination of the geology, hydrogeology, hydro-geochemistry, isotope geochemistry, hydro-geophysics, vadose zone and soil gas processes, microbiology, and atmospheric conditions. The use of unmanned aerial vehicles and remote sensors for monitoring and detection of methane will also be assessed for suitability as environmental monitoring tools. Here we outline the experimental design and describe initial research conducted to develop a detailed site conceptual model of the field observatory. Subsequently, results attained from pilot surface and sub-surface controlled natural gas releases conducted in late summer 2017 will be presented as well as results of numerical modelling conducted

  15. Calculation of gas release from DC and AC arc furnaces in a foundry

    Science.gov (United States)

    Krutyanskii, M. M.; Nekhamin, S. M.; Rebikov, E. M.

    2016-12-01

    A procedure for the calculation of gas release from arc furnaces is presented. The procedure is based on the stoichiometric ratios of the oxidation of carbon in liquid iron during the oxidation heat period and the oxidation of iron from a steel charge by oxygen in the period of solid charge melting during the gas exchange of the furnace cavity with the external atmosphere.

  16. Operating experiences of gas purification system of Heavy Water Plant Talcher (Paper No. 1.11)

    International Nuclear Information System (INIS)

    Bhattacharya, R.; Mohanty, P.R.; Pandey, B.L.

    1992-01-01

    The operating experiences with the purification system installed at Heavy Water Plant, Talcher for purification of feed synthesis gas from fertilizer plant is described. The purification system has performed satisfactorily even with levels of impurities as much as 15 to 20 ppm of oxygen and carbon monoxide. The system could not however be tested at designed gas throughput and on a sustained basis. However, increase in gas throughput upto the design value is not expected to pose any problem on the performance of the purification system. (author). 5 figs

  17. Operational experience in mitigating flammable gas releases from Hanford Site Tank 241-SY-101

    International Nuclear Information System (INIS)

    Lentsch, J.W.; Babad, H.; Kirch, N.W.

    1995-01-01

    Flammable gases consisting of hydrogen, nitrous oxide, ammonia, and methane are periodically released from Hanford Site waste tank 241-SY-101 at concentrations above the flammable limit. A large mixer pump installed in the tank in 1993 has effectively mitigated this problem by continuously releasing small amounts of the flammable gases at the rate they are generated. Tank 241-SY-101 is also equipped with multiple high-sensitivity gas monitoring systems and level detection systems to measure the quantity of gas that is retained in and released from the waste

  18. NORM emissions from heavy oil and natural gas fired power plants in Syria

    International Nuclear Information System (INIS)

    Al-Masri, M.S.; Haddad, Kh.

    2012-01-01

    Naturally occurring radioactive materials (NORM) have been determined in fly and bottom ash collected from four major Syrian power plants fired by heavy oil and natural gas. 210 Pb and 210 Po were the main NORM radionuclides detected in the fly and bottom ash. 210 Pb activity concentrations have reached 3393 ± 10 Bq kg −1 and 4023 ± 7 Bq kg −1 in fly ash and bottom ash, respectively; lower values of 210 Po were observed due to its high volatility. In addition, 210 Po and 210 Pb annual emissions in bottom ash from mixed (heavy oil and natural gas) fired power plants varied between 2.7 × 10 9 –7.95 × 10 9 Bq and 3.5 × 10 9 –10 10 Bq, respectively; higher emissions of 210 Po and 210 Pb from gas power plants being observed. However, the present study showed that 210 Po and 210 Pb emissions from thermal power plants fired by natural gas are much higher than the coal power plants operated in the World. - Highlights: ► NORM have been determined in fly and bottom ash collected from Syrian power plants fired by heavy oil and natural gas. ► 210 Pb and 210 Po were the main NORM radionuclides detected in the fly and bottom ash. ► 210 Po and 210 Pb annual emissions from these power plants were estimated.

  19. Problems of cleaning of gas releases from heat generating facilities

    International Nuclear Information System (INIS)

    Tret'yakov, V.; Burdejnaya, T.

    2000-01-01

    The paper deals with the problem of flue gases cleaning in the situation of a significant increasing use of fossil fuels in the Russian energy production. Information is given about the methods used in TPPs in different countries for cleaning of the gases released to the atmosphere from SO 2 and NO x . The main ways for solving the problem of decreasing of air pollution are outlined

  20. HARAD, Decay Isotope Concentration from Atmospheric Noble-Gas Release

    International Nuclear Information System (INIS)

    Moore, R.E.

    1986-01-01

    1 - Description of problem or function: HARAD calculates concentrations of radioactive daughters in air following the atmospheric release of a parent radionuclide for a variety of release heights and meteorological conditions. It can be applied most profitably to the assessment of doses to man from the noble gases such as Rn-222, Rn-220, and Xe and Kr isotopes. These gases can produce significant quantities of short-lived particulate daughters in an airborne plume, which are the major contributors to dose. The simultaneous processes of radioactive decay, buildup and environmental loss due to wet and dry deposition on ground surfaces are calculated for a daughter chain in an airborne plume as it is dispersed downwind from a point of release of a parent. 2 - Method of solution: The code evaluates the analytic solution to the set of coupled first order differential equations describing time variation of the concentration of a chain of radionuclides. The analytic solutions assume that the coefficient describing the fractional rate of dry deposition is constant with time. To account for the variation the time coordinate is automatically divided into intervals and a set of average values are used. 3 - Restrictions on the complexity of the problem: - The maximum length of decay chain is 10 nuclides; calculations can be made at a maximum of 24 downwind distances

  1. Method of collecting helium cover gas for heavy water moderated reactor

    International Nuclear Information System (INIS)

    Miyamoto, Keiji; Ueda, Hiroshi.

    1981-01-01

    Purpose: To reduce the systematic facility cost in a heavy water moderated reactor by contriving the simplification of a helium cover gas collecting intake system. Method: A detachable low pressure metal tank and a neoprene balloon are prepared for a vacuum pump in a permanent vacuum drying facility. When all of the helium cover gas is collected from a heavy water moderated reactor, a large capacity of neoprene balloon capable of temporarily storing it under low pressure is connected to the exhaust of the vacuum pump. On the other hand, while the reactor is operating, a suitable amount of the low pressure tank or neoprene balloon is connected to the exhaust side of the pump, thereby regulating the pressure of the helium cover gas. When refeeding the cover gas, the balloon, with a large capacity for collecting and storing the cover gas is connected to the intake side of the pump. Thus, the pressure regulation, collection of all of the cover gas and refeeding of the cover gas can be conducted without using a high discharge pump and high pressure tank. (Kamimura, M.)

  2. Preventing Buoyant Displacement Gas Release Events in Hanford Double-Shell Waste Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Perry A.; Stewart, Charles W.

    2001-01-01

    This report summarizes the predictive methods used to ensure that waste transfer operations in Hanford waste tanks do not create waste configurations that lead to unsafe gas release events. The gas release behavior of the waste in existing double-shell tanks has been well characterized, and the flammable gas safety issues associated with safe storage of waste in the current configuration are being formally resolved. However, waste is also being transferred between double-shell tanks and from single-shell tanks into double-shell tanks by saltwell pumping and sluicing that create new wastes and waste configurations that have not been studied as well. Additionally, planning is underway for various waste transfer scenarios to support waste feed delivery to the proposed vitrification plant. It is critical that such waste transfers do not create waste conditions with the potential for dangerous gas release events.

  3. Gas release during salt well pumping: model predictions and comparisons to laboratory experiments

    International Nuclear Information System (INIS)

    Peurrung, L.M.; Caley, S.M.; Bian, E.Y.; Gauglitz, P.A.

    1996-09-01

    The Hanford Site has 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. Some of these wastes are known to generate mixtures of flammable gases, including hydrogen, nitrous oxide, and ammonia. Nineteen of these SSTs have been placed on the Flammable Gas Watch List (FGWL) because they are known or suspected, in all but one case, to retain these flammable gases. Salt well pumping to remove the interstitial liquid from SSTs is expected to cause the release of much of the retained gas, posing a number of safety concerns. Research at the Pacific Northwest National Laboratory (PNNL) has sought to quantify the release of flammable gases during salt well pumping operations. This study is being conducted for Westinghouse Hanford Company as part of the PNNL Flammable Gas Project. Understanding and quantifying the physical mechanisms and waste properties that govern gas release during salt well pumping will help to resolve the associated safety issues

  4. Modeling of modification experiments involving neutral-gas release

    International Nuclear Information System (INIS)

    Bernhardt, P.A.

    1983-01-01

    Many experiments involve the injection of neutral gases into the upper atmosphere. Examples are critical velocity experiments, MHD wave generation, ionospheric hole production, plasma striation formation, and ion tracing. Many of these experiments are discussed in other sessions of the Active Experiments Conference. This paper limits its discussion to: (1) the modeling of the neutral gas dynamics after injection, (2) subsequent formation of ionosphere holes, and (3) use of such holes as experimental tools

  5. Effect of resuspension on the release of heavy metals and water chemistry in anoxic and oxic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Kyung-Yup; Kim, Hong-Seok; Hwang, Inseong [School of Civil and Environmental Engineering, Pusan National University, Busan (Korea, Republic of)

    2011-10-15

    Two types of river sediments with contrasting characteristics (anoxic or oxic) were resuspended and the release of heavy metals and changes in water chemistry were investigated. During resuspension of the anoxic sediment, the dissolved oxygen (DO) concentration and redox potential of the water layer decreased abruptly within the first 1 min, followed by increases toward the end of the resuspension period. Heavy metals were released rapidly in the first 6 h, probably due to the oxidation of acid volatile sulfide (AVS) of the anoxic sediment, and then the aqueous phase concentrations of the heavy metals decreased due to resorption onto the sediment until the 12-h point. During resuspension of the oxic sediment, the DO concentration and redox potential remained relatively constant in the oxic ranges. The heavy metals were released from the oxic sediment gradually during a 24-h resuspension period. The temporal maximum concentrations of Ni, Cu, Zn, and Cd in the aqueous phases in both experiments frequently exceeded the USEPA water quality criteria or the water quality guidelines of Australia and New Zealand. This suggests that a resuspension event could bring about temporal water quality deterioration in the two sediment environments. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Fire damp gas in a heavy water reactor; Praskavi gas u teskovodnom reaktoru

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, V D [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Yugoslavia)

    1963-07-01

    This document describes the process of fire damp gas creation in the reactor core and dependence of the gas percentage on the temperature, i.e. reactor power. It contains a detailed plan for measuring the the percent of fire damp gas at the RA reactor: before start-up, after longer shut-down periods, immediately after safety shutdown, periodically during operation campaign.

  7. Problems of hydrogen - water vapor - inert gas mixture use in heavy liquid metal coolant technology

    International Nuclear Information System (INIS)

    Ul'yanov, V.V.; Martynov, P.N.; Gulevskij, V.A.; Teplyakov, Yu.A.; Fomin, A.S.

    2014-01-01

    The reasons of slag deposit formation in circulation circuits with heavy liquid metal coolants, which can cause reactor core blockage, are considered. To prevent formation of deposits hydrogen purification of coolant and surfaces of circulation circuit is used. It consists in introduction of gaseous mixtures hydrogen - water vapor - rare gas (argon or helium) directly into coolant flow. The principle scheme of hydrogen purification and the processes occurring during it are under consideration. Measures which make it completely impossible to overlap of the flow cross section of reactor core, steam generators, pumps and other equipment by lead oxides in reactor facilities with heavy liquid metal coolants are listed [ru

  8. Analysis of oxidised heavy paraffininc products by high temperature comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Potgieter, H; Bekker, R; Beigley, J; Rohwer, E

    2017-08-04

    Heavy petroleum fractions are produced during crude and synthetic crude oil refining processes and they need to be upgraded to useable products to increase their market value. Usually these fractions are upgraded to fuel products by hydrocracking, hydroisomerization and hydrogenation processes. These fractions are also upgraded to other high value commercial products like lubricant oils and waxes by distillation, hydrogenation, and oxidation and/or blending. Oxidation of hydrogenated heavy paraffinic fractions produces high value products that contain a variety of oxygenates and the characterization of these heavy oxygenates is very important for the control of oxidation processes. Traditionally titrimetric procedures are used to monitor oxygenate formation, however, these titrimetric procedures are tedious and lack selectivity toward specific oxygenate classes in complex matrices. Comprehensive two-dimensional gas chromatography (GC×GC) is a way of increasing peak capacity for the comprehensive analysis of complex samples. Other groups have used HT-GC×GC to extend the carbon number range attainable by GC×GC and have optimised HT-GC×GC parameters for the separation of aromatics, nitrogen-containing compounds as well as sulphur-containing compounds in heavy petroleum fractions. HT-GC×GC column combinations for the separation of oxygenates in oxidised heavy paraffinic fractions are optimised in this study. The advantages of the HT-GC×GC method in the monitoring of the oxidation reactions of heavy paraffinic fraction samples are illustrated. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Unregulated greenhouse gas and ammonia emissions from current technology heavy-duty vehicles.

    Science.gov (United States)

    Thiruvengadam, Arvind; Besch, Marc; Carder, Daniel; Oshinuga, Adewale; Pasek, Randall; Hogo, Henry; Gautam, Mridul

    2016-11-01

    The study presents the measurement of carbonyl, BTEX (benzene, toluene, ethyl benzene, and xylene), ammonia, elemental/organic carbon (EC/OC), and greenhouse gas emissions from modern heavy-duty diesel and natural gas vehicles. Vehicles from different vocations that included goods movement, refuse trucks, and transit buses were tested on driving cycles representative of their duty cycle. The natural gas vehicle technologies included the stoichiometric engine platform equipped with a three-way catalyst and a diesel-like dual-fuel high-pressure direct-injection technology equipped with a diesel particulate filter (DPF) and a selective catalytic reduction (SCR). The diesel vehicles were equipped with a DPF and SCR. Results of the study show that the BTEX emissions were below detection limits for both diesel and natural gas vehicles, while carbonyl emissions were observed during cold start and low-temperature operations of the natural gas vehicles. Ammonia emissions of about 1 g/mile were observed from the stoichiometric natural gas vehicles equipped with TWC over all the driving cycles. The tailpipe GWP of the stoichiometric natural gas goods movement application was 7% lower than DPF and SCR equipped diesel. In the case of a refuse truck application the stoichiometric natural gas engine exhibited 22% lower GWP than a diesel vehicle. Tailpipe methane emissions contribute to less than 6% of the total GHG emissions. Modern heavy-duty diesel and natural gas engines are equipped with multiple after-treatment systems and complex control strategies aimed at meeting both the performance standards for the end user and meeting stringent U.S. Environmental Protection Agency (EPA) emissions regulation. Compared to older technology diesel and natural gas engines, modern engines and after-treatment technology have reduced unregulated emissions to levels close to detection limits. However, brief periods of inefficiencies related to low exhaust thermal energy have been shown to

  10. Evaporation release behavior of volatile fission products from liquid sodium pool to the inert cover gas

    Energy Technology Data Exchange (ETDEWEB)

    Nakagiri, T; Miyahara, S [Oarai Engineering Center, Power Reactor and Nuclear Fuel Development Corp., Oaraimachi, Ibaraki (Japan)

    1996-12-01

    In fuel failure of sodium cooled fast breeder reactors, released volatile fission products (VFPs) such as iodine and cesium from the fuel will be dissolved into the liquid sodium coolant and transferred to the cover vaporization. In the cover gas system of the reactor, natural convection occurs due to temperature differences between the sodium pool and the gas phase. The release rates of VFPs together with sodium vaporization are considered to be controlled by the convection. In this study, three analytical models are developed and examined to calculate the transient release rates using the equilibrium partition coefficients of VFPs. The calculated release rates are compared with experimental results for sodium and sodium iodide. The release rate of sodium is closest to the calculation by the heterogeneous nucleation theory. The release rate of sodium iodide obtained from the experiment is between the release rates calculated by the model based on heat-and-mass transfer analogy and the Hill`s theory. From this study, it is confirmed that the realistic release rate of sodium is able to be calculated by the model based on the heterogeneous nucleation theory. The conservative release rate of sodium iodide is able to be calculated by the model based on the Hill`s theory using the equilibrium partition coefficient of sodium iodide. (author) 7 figs., 1 tab., 3 refs.

  11. Safety barriers on oil and gas platforms. Means to prevent hydrocarbon releases

    Energy Technology Data Exchange (ETDEWEB)

    Sklet, Snorre

    2005-12-15

    The main objective of the PhD project has been to develop concepts and methods that can be used to define, illustrate, analyse, and improve safety barriers in the operational phase of offshore oil and gas production platforms. The main contributions of this thesis are; Clarification of the term safety barrier with respect to definitions, classification, and relevant attributes for analysis of barrier performance Development and discussion of a representative set of hydrocarbon release scenarios Development and testing of a new method, BORA-Release, for qualitative and quantitative risk analysis of hydrocarbon releases Safety barriers are defined as physical and/or non-physical means planned to prevent, control, or mitigate undesired events or accidents. The means may range from a single technical unit or human actions, to a complex socio-technical system. It is useful to distinguish between barrier functions and barrier systems. Barrier functions describe the purpose of safety barriers or what the safety barriers shall do in order to prevent, control, or mitigate undesired events or accidents. Barrier systems describe how a barrier function is realized or executed. If the barrier system is functioning, the barrier function is performed. If a barrier function is performed successfully, it should have a direct and significant effect on the occurrence and/or consequences of an undesired event or accident. It is recommended to address the following attributes to characterize the performance of safety barriers; a) functionality/effectiveness, b) reliability/ availability, c) response time, d) robustness, and e) triggering event or condition. For some types of barriers, not all the attributes are relevant or necessary in order to describe the barrier performance. The presented hydrocarbon release scenarios include initiating events, barrier functions introduced to prevent hydrocarbon releases, and barrier systems realizing the barrier functions. Both technical and human

  12. A review of selected aspects of the effect of water vapor on fission gas release from uranium oxycarbide

    International Nuclear Information System (INIS)

    Myers, B.F.

    1994-04-01

    A selective review is presented of previous measurements and the analysis of experiments on the effect of water vapor on fission gas release from uranium oxycarbide. Evidence for the time-dependent composition of the uranium oxycarbide fuel; the diffusional release of fission gas; and the initial, rapid and limited release of stored fission gas is discussed. In regard to the initial, rapid release of fission gas, clear restrictions on mechanistic hypotheses can be deduced from the experimental data. However, more fundamental experiments may be required to establish the mechanism of the rapid release

  13. Experience of iodine, caesium and noble gas release from AGR failures

    International Nuclear Information System (INIS)

    Chapman, C.J.; Harris, A.M.; Phillips, M.E.

    1985-01-01

    In the event of a fuel failure in an Advanced Gas Cooled Reactor (AGR), the quantity of fission products available for release to the environment is determined by the transport of fission products in the UO 2 fuel, by the possible retention of fission products in the fuel can interspace and by the deposition of fission products on gas circuit surfaces ('plate-out'). The fission products of principal radiological concern are radioactive caesium (Cs-137 and Cs-134) and iodine (principally I-131). Results are summarised of a number of experiments which were designed to study the release of these fission products from individual fuel failures in the prototype AGR at Windscale. Results are also presented of fission product release from failures in commercial AGRs. Comparisons of measured releases of caesium and iodine relative to the release of the noble gas fission products show that, for some fuel failures, there is a significant retention of caesium and iodine within the fuel can interspace. Under normal conditions circuit deposition reduces caesium and iodine gas concentrations by several orders of magnitude. Differing release behaviour of caesium and iodine from the failures is examined together with subsequent deposition within the sampling equipment. These observations are important factors which must be considered in developing an understanding of the mechanisms involved in circuit deposition. (author)

  14. On-Line Fission Gas Release Monitoring System in the High Flux Reactor Petten

    International Nuclear Information System (INIS)

    Laurie, M.; Fuetterer, M. A.; Appelman, K.H.; Lapetite, J.-M.; Marmier, A.; Knol, S.; Best, J.

    2013-06-01

    For HTR fuel irradiation tests in the HFR Petten a specific installation was designed and installed dubbed the 'Sweep Loop Facility' (SLF). The SLF is tasked with three functions, namely temperature control by gas mixture technique, surveillance of safety parameters (temperature, pressure, radioactivity etc.) and analysis of fission gas release for three individual capsules in two separate experimental rigs. The SLF enables continuous and independent surveillance of all gas circuits. The release of volatile fission products (FP) from the in-pile experiments is monitored by continuous gas purging. The fractional release of these FP, defined as the ratio between release rate of a gaseous fission isotope (measured) to its instantaneous birth rate (calculated), is a licensing-relevant test for HTR fuel. The developed gamma spectrometry station allows for higher measurement frequencies, thus enabling follow-up of rapid and massive release transients. The designed stand-alone system was tested and fully used through the final irradiation period of the HFR-EU1 experiment which was terminated on 18 February 2010. Its robustness allowed the set up to be used as extra safety instrumentation. This paper describes the gas activity measurement technique based on HPGe gamma spectrometry and illustrates how qualitative and quantitative analysis of volatile FP can be performed on-line. (authors)

  15. Transient fission gas release from UO2 fuel for high temperature and high burnup

    International Nuclear Information System (INIS)

    Szuta, M.

    2001-01-01

    In the present paper it is assumed that the fission gas release kinetics from an irradiated UO 2 fuel for high temperature is determined by the kinetics of grain growth. A well founded assumption that Vitanza curve describes the change of uranium dioxide re-crystallization temperature and the experimental results referring to the limiting grain size presented in the literature are used to modify the grain growth model. Algorithms of fission gas release due to re-crystallization of uranium dioxide grains are worked out. The defect trap model of fission gas behaviour described in the earlier papers is supplemented with the algorithms. Calculations of fission gas release in function of time, temperature, burn-up and initial grain sizes are obtained. Computation of transient fission gas release in the paper is limited to the case where steady state of irradiation to accumulate a desired burn-up is performed below the temperature of re-crystallization then the subsequent step temperature increase follows. There are considered two kinds of step temperature increase for different burn-up: the final temperature of the step increase is below and above the re-crystallization temperature. Calculations show that bursts of fission gas are predicted in both kinds. The release rate of gas liberated for the final temperature above the re-crystallization temperature is much higher than for final temperature below the re-crystallization temperature. The time required for the burst to subside is longer due to grain growth than due to diffusion of bubbles and knock-out release. The theoretical results explain qualitatively the experimental data but some of them need to be verified since this sort of experimental data are not found in the available literature. (author)

  16. Reduction of prostate intrafraction motion using gas-release rectal balloons

    International Nuclear Information System (INIS)

    Su Zhong; Zhao Tianyu; Li Zuofeng; Hoppe, Brad; Henderson, Randy; Mendenhall, William; Nichols, R. Charles; Marcus, Robert; Mendenhall, Nancy

    2012-01-01

    Purpose: To analyze prostate intrafraction motion using both non-gas-release (NGR) and gas-release (GR) rectal balloons and to evaluate the ability of GR rectal balloons to reduce prostate intrafraction motion. Methods: Twenty-nine patients with NGR rectal balloons and 29 patients with GR balloons were randomly selected from prostate patients treated with proton therapy at University of Florida Proton Therapy Institute (Jacksonville, FL). Their pretreatment and post-treatment orthogonal radiographs were analyzed, and both pretreatment setup residual error and intrafraction-motion data were obtained. Population histograms of intrafraction motion were plotted for both types of balloons. Population planning target-volume (PTV) margins were calculated with the van Herk formula of 2.5Σ+ 0.7σ to account for setup residual errors and intrafraction motion errors. Results: Pretreatment and post-treatment radiographs indicated that the use of gas-release rectal balloons reduced prostate intrafraction motion along superior–inferior (SI) and anterior–posterior (AP) directions. Similar patient setup residual errors were exhibited for both types of balloons. Gas-release rectal balloons resulted in PTV margin reductions from 3.9 to 2.8 mm in the SI direction, 3.1 to 1.8 mm in the AP direction, and an increase from 1.9 to 2.1 mm in the left–right direction. Conclusions: Prostate intrafraction motion is an important uncertainty source in radiotherapy after image-guided patient setup with online corrections. Compared to non-gas-release rectal balloons, gas-release balloons can reduce prostate intrafraction motion in the SI and AP directions caused by gas buildup.

  17. Reduction of prostate intrafraction motion using gas-release rectal balloons

    Energy Technology Data Exchange (ETDEWEB)

    Su Zhong; Zhao Tianyu; Li Zuofeng; Hoppe, Brad; Henderson, Randy; Mendenhall, William; Nichols, R. Charles; Marcus, Robert; Mendenhall, Nancy [Department of Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, Florida 32206 (United States)

    2012-10-15

    Purpose: To analyze prostate intrafraction motion using both non-gas-release (NGR) and gas-release (GR) rectal balloons and to evaluate the ability of GR rectal balloons to reduce prostate intrafraction motion. Methods: Twenty-nine patients with NGR rectal balloons and 29 patients with GR balloons were randomly selected from prostate patients treated with proton therapy at University of Florida Proton Therapy Institute (Jacksonville, FL). Their pretreatment and post-treatment orthogonal radiographs were analyzed, and both pretreatment setup residual error and intrafraction-motion data were obtained. Population histograms of intrafraction motion were plotted for both types of balloons. Population planning target-volume (PTV) margins were calculated with the van Herk formula of 2.5{Sigma}+ 0.7{sigma} to account for setup residual errors and intrafraction motion errors. Results: Pretreatment and post-treatment radiographs indicated that the use of gas-release rectal balloons reduced prostate intrafraction motion along superior-inferior (SI) and anterior-posterior (AP) directions. Similar patient setup residual errors were exhibited for both types of balloons. Gas-release rectal balloons resulted in PTV margin reductions from 3.9 to 2.8 mm in the SI direction, 3.1 to 1.8 mm in the AP direction, and an increase from 1.9 to 2.1 mm in the left-right direction. Conclusions: Prostate intrafraction motion is an important uncertainty source in radiotherapy after image-guided patient setup with online corrections. Compared to non-gas-release rectal balloons, gas-release balloons can reduce prostate intrafraction motion in the SI and AP directions caused by gas buildup.

  18. Overview of the Safety Issues Associated with the Compressed Natural Gas Fuel System and Electric Drive System in a Heavy Hybrid Electric Vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.C.

    2002-11-14

    reliable vehicle with a lower availability than a conventional heavy vehicle. Experience with heavy HEVs to date supports this observation. The key safety concern for the electric drive system is the higher voltages and currents that are required in the electric drive system. Faults that could expose personnel to these electric hazards must be considered, addressed, and minimized. The key issue for the CNG-fueled ICE is containment of the high-pressure natural gas. Events that can result in a release of natural gas with the possibility of subsequent ignition are of concern. These safety issues are discussed. The heavy HEV has the potential to have a safety record that is comparable to that of the conventional vehicle, but adequate attention to detail will be required.

  19. Application of the dose limitation system to the control of carbon-14 releases from heavy-water-moderated reactors

    International Nuclear Information System (INIS)

    Beninson, D.; Gonzalez, A.J.

    1982-01-01

    Heavy-water-moderated reactors produce substantially more carbon-14 than light-water reactors. Applying the principles of the systems of dose limitation, the paper presents the rationale used for establishing the release limit for effluents containing this nuclide and for the decisions made regarding the effluent treatment in the third nuclear power station in Argentina. Production of carbon-14 in PHWR and the release routes are analysed in the light of the different effluent treatment possibilities. An optimization assessment is presented, taking into account effluent treatment and waste management costs, and the collective effective dose commitment due to the releases. The contribution of present carbon-14 releases to future individual doses is also analysed in the light of an upper bound for the contribution, representing a fraction of the individual dose limits. The paper presents the resulting requirements for the effluent treatment regarding carbon-14 and the corresponding regulatory aspects used in Argentina. (author)

  20. Fundamental Study of Disposition and Release of Methane in a Shale Gas Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Xiong, Yongliang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Repository Performance; Criscenti, Louise J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geochemistry; Ho, Tuan Ahn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geochemistry; Weck, Philippe F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Storage and Transportation Technology; Ilgen, Anastasia G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geochemistry; Matteo, Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Kruichak, Jessica N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Mills, Melissa M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Dewers, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geomechanics; Gordon, Margaret E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Materials, Devices and Energy Technologies; Akkutlu, Yucel [Texas A & M Univ., College Station, TX (United States). Dept. of Petroleum Engineering

    2016-09-01

    The recent boom in shale gas production through hydrofracturing has reshaped the energy production landscape in the United States. Wellbore production rates vary greatly among the wells within a single field and decline rapidly with time, thus bring up a serious concern with the sustainability of shale gas production. Shale gas production starts with creating a fracture network by injecting a pressurized fluid in a wellbore. The induced fractures are then held open by proppant particles. During production, gas releases from the mudstone matrix, migrates to nearby fractures, and ultimately reaches a production wellbore. Given the relatively high permeability of the induced fractures, gas release and migration in low-permeability shale matrix is likely to be a limiting step for long-term wellbore production. Therefore, a clear understanding of the underlying mechanisms of methane disposition and release in shale matrix is crucial for the development of new technologies to maximize gas production and recovery. Shale is a natural nanocomposite material with distinct characteristics of nanometer-scale pore sizes, extremely low permeability, high clay contents, significant amounts of organic carbon, and large spatial heterogeneities. Our work has shown that nanopore confinement plays an important role in methane disposition and release in shale matrix. Using molecular simulations, we show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~ 30 - 47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. The long-term production decline appears controlled by the second stage of gas release. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD

  1. 76 FR 57105 - Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty...

    Science.gov (United States)

    2011-09-15

    ... CFR Parts 523, 534, and 535 Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for...-2010-0079; FRL-9455-1] RIN 2060-AP61; 2127-AK74 Greenhouse Gas Emissions Standards and Fuel Efficiency... Heavy-Duty National Program that will reduce greenhouse gas emissions and fuel consumption for on-road...

  2. 75 FR 81952 - Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty...

    Science.gov (United States)

    2010-12-29

    ...-HQ-OAR-2010-0162; FRL-9219-4; NHTSA 2010-0079] RIN 2060-AP61; RIN 2127-AK74 Greenhouse Gas Emissions... will increase fuel efficiency and reduce greenhouse gas emissions for on-road heavy-duty vehicles...-Duty National Program that will increase fuel efficiency and reduce greenhouse gas emissions for on...

  3. Effect of axial diffusional delays on the overall fission gas release

    International Nuclear Information System (INIS)

    Pedersen, N.K.

    1983-01-01

    In fission gas release modeling, it is normally assumed that any locally released gas mixes instantly and perfectly with other gases throughout the internal rod void volume. The present work investigates the consequences of the assumption that perfect mixing is dependent on diffusion, although the subassumption is maintained that pressure equilibrium is instantly achieved. In other words, when a burst of gas release occurs at any axial location, sufficient local accommodation takes place throughout the rod to eliminate any pressure gradients, but due to the narrowness of the passages through fuel cracks and fuel-cladding gap, concentration gradients may still prevail. Diffusion coefficients for the subsequent concentration equilibration are derived from classical theories. Application of one-dimensional diffusion theory is straightforward, but the lack of knowledge of the effective width of the axial passage introduces an uncertainty

  4. Life-cycle greenhouse gas analysis of LNG as a heavy vehicle fuel in Europe

    International Nuclear Information System (INIS)

    Arteconi, A.; Brandoni, C.; Evangelista, D.; Polonara, F.

    2010-01-01

    The aim of the present study was to compare the life cycle, in terms of greenhouse gas (GHG) emissions, of diesel and liquefied natural gas (LNG) used as fuels for heavy-duty vehicles in the European market (EU-15). A literature review revealed that the numerous studies conducted have reported different results when the authors departed from different baseline assumptions and reference scenarios. For our study, we concentrated on the European scenario and on heavy-duty road transport vehicles, given their important incidence on the global emissions of GHG. Two possible LNG procurement strategies were considered i.e. purchasing it directly from the regasification terminal (LNG-TER) or producing LNG locally (at the service station) with small-scale plants (LNG-SSL). We ascertained that the use of LNG-TER enables a 10% reduction in GHG emissions by comparison with diesel, while the emissions resulting from the LNG-SSL solution are comparable with those of diesel.

  5. Thermodynamic characterization of deepwater natural gas mixtures with heavy hydrocarbon content at high pressures

    International Nuclear Information System (INIS)

    Atilhan, Mert; Aparicio, Santiago; Ejaz, Saquib; Zhou, Jingjun; Al-Marri, Mohammed; Holste, James J.; Hall, Kenneth R.

    2015-01-01

    This paper includes high-accuracy density measurements and phase envelopes for deepwater natural gas mixtures. Mixtures primarily consist of (0.88 and 0.94) mole fraction methane and both mixtures includes heavy components (C 6+ ) more than 0.002 mole fraction. Experimental density and phase envelope data for deep and ultra-deep reservoir mixtures are scarce in literature and high accuracy measurements for such parameters for such natural gas-like mixtures are essential to validate the benchmark equations for custody transfer such as AGA8-DC92 and GERG-2008 equation of states (EOS). Thus, in this paper we report density and phase envelope experimental data via compact single-sinker magnetic suspension densimeter and isochoric apparatuses. Such data help gas industry to avoid retrograde condensation in natural gas pipelines

  6. Macroscopic calculational model of fission gas release from water reactor fuels

    International Nuclear Information System (INIS)

    Uchida, Masaki

    1993-01-01

    Existing models for estimating fission gas release rate usually have fuel temperature as independent variable. Use of fuel temperature, however, often brings an excess ambiguity in the estimation because it is not a rigorously definable quantity as a function of heat generation rate and burnup. To derive a mathematical model that gives gas release rate explicitly as a function of design and operational parameters, the Booth-type diffusional model was modified by changing the character of the diffusion constant from physically meaningful quantity into a mere mathematical parameter, and also changing its temperature dependency into power dependency. The derived formula was found, by proper choice of arbitrary constants, to satisfactorily predict the release rates under a variety of irradiation histories up to a burnup of 60,000 MWd/t. For simple power histories, the equation can be solved analytically by defining several transcendental functions, which enables simple calculation of release rate using graphs. (author)

  7. Heavy particle detection characteristics of an MWPC operating at low (1 <= p <= 30 mbar) gas pressures

    International Nuclear Information System (INIS)

    Moeller, G.; Presser, G.; Staehler, J.

    1981-01-01

    Pulse heights, timing properties and detection efficiencies of an MWPC were measured with 5.5 MeV alpha particles for different counting gases at low pressures. The pulse heights show a striking nonmonotonic dependence on the gas pressure that can be explained by a simple model of the amplification process at high reduced electric fields. The consequences of the observed pressure dependence of pulse heights for the detection of heavy ions with low pressure MWPCs are discussed. (orig.)

  8. In-reactor measurements of thermo mechanical behaviour and fission gas release of water reactor fuel

    International Nuclear Information System (INIS)

    Kolstad, E.; Vitanza, C.

    1983-01-01

    the fuel performance during and after a power ramp can be investigated by direct in-pile measurements related to the thermal, mechanical and fission gas release behaviour. The thermal response is examined by thermocouples placed at the centre of the fuel. Such measurements allow the determination of thermal feedback effects induced by the simultaneous liberation of fission gases. The thermal feedback effect is also being separately studied out-of-pile in a specially designed rod where the fission gas release is simulated by injecting xenon in known quantities at different axial positions within the rod. Investigations on the mechanical behaviour are based on axial and diametral cladding deformation measurements. This enables the determination of the amount of local cladding strain and ridging during ramping, the extent of relaxation during the holding time and the amount of residual (plastic) deformation. Gap width measurements are also performed in operating fuel rods using a cladding deflection technique. Fission gas release data are obtained, besides from post-irradiation puncturing, by continuous measurements of the rod internal pressure. This type of measurement leads to the description of the kinetics of the fission gas release process at different powers. The data tend to indicate that the time-dependent release can be reasonably well described by simple diffusion. The paper describes measuring techniques developed and currently in use in Halden, and presents and discusses selected experimental results obtained during various power ramps and transients. (author)

  9. Physical mechanisms contributing to the episodic gas release from Hanford tank 241-SY-101

    International Nuclear Information System (INIS)

    Allemann, R.T.

    1992-04-01

    Volume growth of contents in a waste storage tank at Hanford is accompanied by episodic releases of gas and a rise in the level of tank contents. A theory is presented to describe how the gas is retained in the waste and how it is released. The theory postulates that somewhat cohesive gobs of sludge rise from the lower regions of the tank and buoyancy overcomes the cohesive strength of the slurry; this quantitatively explains several of the measured phenomena and qualitatively explains other observations

  10. Fission gas release from UO2 pellet fuel at high burn-up

    International Nuclear Information System (INIS)

    Vitanza, C.; Kolstad, E.; Graziani, U.

    1979-01-01

    Analysis of in-reactor measurements of fuel center temperature and rod internal pressure at the OECD Halden Reactor Project has led to the development of an empirical fission gas release model, which is described. The model originally derived from data obtained in the low and intermediate burn-up range, appears to give good predictions for rods irradiated to high exposures as well. PIE puncturing data from seven fuel rods, operated at relatively constant powers and peak center temperatures between 1900 and 2000 0 C up to approx. 40,000 MWd/t UO 2 , did not exhibit any burn-up enhancement on the fission gas release rate

  11. Finite element simulation of fission gas release and swelling in UO2 fuel pellets

    International Nuclear Information System (INIS)

    Denis, Alicia C.

    1999-01-01

    A fission gas release model is presented, which solves the atomic diffusion problem with xenon and krypton elements tramps produced by uranium fission during UO 2 nuclear fuel irradiation. The model considers intra and intergranular precipitation bubbles, its re dissolution owing to highly energetic fission products impact, interconnection of intergranular bubbles and gas sweeping by grain border in movement because of grain growth. In the model, the existence of a thermal gradient in the fuel pellet is considered, as well as temporal variations of fission rate owing to changes in the operation lineal power. The diffusion equation is solved by the finite element method and results of gas release and swelling calculation owing to gas fission are compared with experimental data. (author)

  12. Modeling fission gas release in high burnup ThO2-UO2 fuel

    International Nuclear Information System (INIS)

    Long, Y.; Yuan, Y.; Pilat, E.E.; Rim, C.S.; Kazimi, M.S.

    2001-01-01

    A preliminary fission gas release model to predict the performance of thoria fuel using the FRAPCON-3 computer code package has been formulated. The following modeling changes have been made in the code: - Radial power/burnup distribution; - Thermal conductivity and thermal expansion; - Rim porosity and fuel density; - Diffusion coefficient of fission gas in ThO 2 -UO 2 fuel and low temperature fission gas release model. Due to its lower epithermal resonance absorption, thoria fuel experiences a much flatter distribution of radial fissile products and radial power distribution during operation as compared to uranian fuel. The rim effect and its consequences in thoria fuel, therefore, are expected to occur only at relatively high burnup levels. The enhanced conductivity is evident for ThO 2 , but for a mixture the thermal conductivity enhancement is small. The lower thermal fuel expansion tends to negate these small advantages. With the modifications above, the new version of FRAPCON-3 matched the measured fission gas release data reasonably well using the ANS 5.4 fission gas release model. (authors)

  13. GRSIS program to predict fission gas release and swelling behavior of metallic fast reactor fuel

    International Nuclear Information System (INIS)

    Lee, Chan Bock; Lee, Byung Ho; Nam, Cheol; Sohn, Dong Seong

    1999-03-01

    A mechanistic model of fission gas release and swelling for the U-(Pu)-Zr metallic fuel in the fast reactor, GRSIS (Gas Release and Swelling in ISotropic fuel matrix) was developed. Fission gas bubbles are assumed to nucleate isotropically from the gas atoms in the metallic fuel matrix since they can nucleate at both the grain boundaries and the phase boundaries which are randomly distributed inside the grain. Bubbles can grow to larger size by gas diffusion and coalition with other bubbles so that they are classified as three classes depending upon their sizes. When bubble swelling reaches the threshold value, bubbles become interconnected each other to make the open channel to the external free space, that is, the open bubbles and then fission gases inside the interconnected open bubbles are released instantaneously. During the irradiation, fission gases are released through the open bubbles. GRSIS model can take into account the fuel gap closure by fuel bubble swelling. When the fuel gap is closed by fuel swelling, the contact pressure between fuel and cladding in relation to the bubble swelling and temperature is calculated. GRSIS model was validated by comparison with the irradiation test results of U-(Pu)-Zr fuels in ANL as well as the parametric studies of the key variable in the model. (author). 13 refs., 1 tab., 22 figs

  14. GRSIS program to predict fission gas release and swelling behavior of metallic fast reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chan Bock; Lee, Byung Ho; Nam, Cheol; Sohn, Dong Seong

    1999-03-01

    A mechanistic model of fission gas release and swelling for the U-(Pu)-Zr metallic fuel in the fast reactor, GRSIS (Gas Release and Swelling in ISotropic fuel matrix) was developed. Fission gas bubbles are assumed to nucleate isotropically from the gas atoms in the metallic fuel matrix since they can nucleate at both the grain boundaries and the phase boundaries which are randomly distributed inside the grain. Bubbles can grow to larger size by gas diffusion and coalition with other bubbles so that they are classified as three classes depending upon their sizes. When bubble swelling reaches the threshold value, bubbles become interconnected each other to make the open channel to the external free space, that is, the open bubbles and then fission gases inside the interconnected open bubbles are released instantaneously. During the irradiation, fission gases are released through the open bubbles. GRSIS model can take into account the fuel gap closure by fuel bubble swelling. When the fuel gap is closed by fuel swelling, the contact pressure between fuel and cladding in relation to the bubble swelling and temperature is calculated. GRSIS model was validated by comparison with the irradiation test results of U-(Pu)-Zr fuels in ANL as well as the parametric studies of the key variable in the model. (author). 13 refs., 1 tab., 22 figs.

  15. Modelling intragranular fission gas release in irradiation of sintered LWR UO2 fuel

    International Nuclear Information System (INIS)

    Loesoenen, Pekka

    2002-01-01

    A model for the release of stable fission gases by diffuion from sintered LWR UO 2 fuel grains is presented. The model takes into account intragranular gas bubble behaviour as a function of grain radius. The bubbles are assumed to be immobile and the gas migrates to grain boundaries by diffusion of single gas atoms. The intragranular bubble population in the model at low burn-ups or temperatures consists of numerous small bubbles. The presence of the bubbles attenuates the effective gas atom diffusion coefficient. Rapid coarsening of the bubble population in increased burn-up at elevated temperatures weakens significantly the attenuation of the effective diffusion coefficient. The solution method introduced in earlier papers, locally accurate method, is enhanced to allow accurate calculation of the intragranular gas behaviour in time varying conditions without excessive computing time. Qualitatively the detailed model can predict the gas retention in the grain better than a more simple model

  16. EQUATIONS FOR GAS RELEASING PROCESS FROM PRESSURIZED VESSELS IN ODH EVALUATION

    International Nuclear Information System (INIS)

    JIA, L.X.; WANG, L.

    2001-01-01

    IN THE EVALUATION OF ODH, THE CALCULATION OF THE SPILL RATE FROM THE PRESSURIZED VESSEL IS THE CENTRAL TASK. THE ACCURACY OF THE ENGINEERING ESTIMATION BECOMES ONE OF THE SAFETY DESIGN ISSUES. THIS PAPER SUMMARIZES THE EQUATIONS FOR THE OXYGEN CONCENTRATION CALCULATION IN DIFFERENT CASES, AND DISCUSSES THE EQUATIONS FOR THE GAS RELEASE PROCESS CALCULATION BOTH FOR THE HIGH-PRESSURE GAS TANK AND THE LOW-TEMPERATURE LIQUID CONTAINER

  17. Sunlight Induced Rapid Oil Absorption and Passive Room-Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

    KAUST Repository

    Wu, Mengchun

    2018-05-18

    Rapid cleanup and easy recovery of spilled heavy oils is always a great challenge due to their high viscosity (>103 mPa s). One of the efficient methods to absorb highly viscous oils is to reduce their viscosity by increasing their temperature. In this work, the authors integrate the sunlight‐induced light‐to‐heat conversion effect of polypyrrole (PPy) and thermoresponsive property of poly(N‐isopropylacrylamide) (PNIPAm) into the melamine sponge, which successfully delivers a fast heavy oil absorption under sunlight and passive oil release underwater at room temperature. Thanks to the rationally designed functionalities, the PNIPAm/PPy functionalized sponges possess oleophilicity and hydrophobicity under sunlight. Due to the photothermal effect of PPy, the sponges locally heat up contacting heavy oil under sunlight and reduce its viscosity to a point where the oil voluntarily flow into the pores of the sponge. The material in this work is able to rapidly absorb the heavy oil with room temperature viscosity as high as ≈1.60 × 105 mPa s. The absorbed oil can be passively forced out the sponge underwater at room temperature due to the hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming up with a sustainable solution toward heavy oil spill.

  18. Sunlight Induced Rapid Oil Absorption and Passive Room-Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

    KAUST Repository

    Wu, Mengchun; Shi, Yusuf; Chang, Jian; Li, Renyuan; Ong, Chi Siang; Wang, Peng

    2018-01-01

    Rapid cleanup and easy recovery of spilled heavy oils is always a great challenge due to their high viscosity (>103 mPa s). One of the efficient methods to absorb highly viscous oils is to reduce their viscosity by increasing their temperature. In this work, the authors integrate the sunlight‐induced light‐to‐heat conversion effect of polypyrrole (PPy) and thermoresponsive property of poly(N‐isopropylacrylamide) (PNIPAm) into the melamine sponge, which successfully delivers a fast heavy oil absorption under sunlight and passive oil release underwater at room temperature. Thanks to the rationally designed functionalities, the PNIPAm/PPy functionalized sponges possess oleophilicity and hydrophobicity under sunlight. Due to the photothermal effect of PPy, the sponges locally heat up contacting heavy oil under sunlight and reduce its viscosity to a point where the oil voluntarily flow into the pores of the sponge. The material in this work is able to rapidly absorb the heavy oil with room temperature viscosity as high as ≈1.60 × 105 mPa s. The absorbed oil can be passively forced out the sponge underwater at room temperature due to the hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming up with a sustainable solution toward heavy oil spill.

  19. Gas-Liquid Precipitation of water dissolved heavy metal ions using hydrogen sulfide gas

    NARCIS (Netherlands)

    Al Tarazi, M.Y.M.

    2004-01-01

    Precipitation of solids promoted by gas-liquid reactions is applied in many industrial processes such as the production of ammonium phosphate, ammonium sulphate, barium carbonate, calcium carbonate, calcium fluoride, ypsum (calcium sulphate), goethite, sodium bicarbonate, strontium carbonate and

  20. The influence of cladding on fission gas release from irradiated U-Mo monolithic fuel

    Energy Technology Data Exchange (ETDEWEB)

    Burkes, Douglas E., E-mail: Douglas.Burkes@pnnl.gov; Casella, Amanda J.; Casella, Andrew M.

    2017-04-01

    The monolithic uranium-molybdenum (U-Mo) alloy has been proposed as a fuel design capable of converting the world's highest power research reactors from use of high enriched uranium to low enriched uranium. However, a zirconium (Zr) diffusion barrier must be used to eliminate interactions that form between the U-Mo monolith and aluminum alloy 6061 (AA6061) cladding during fabrication and are enhanced during irradiation. One aspect of fuel development and qualification is to demonstrate an appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. An exothermic reaction has previously been observed between the AA6061 cladding and Zr diffusion layer. In this paper, two fuel segments with different irradiation history were subjected to specified thermal profiles under a controlled atmosphere using a thermogravimetric/differential thermal analyzer coupled with a mass spectrometer inside a hot cell. Samples from each segment were tested with cladding and without cladding to investigate the effect, if any, that the exothermic reaction has on fission gas release mechanisms. Measurements revealed there is an instantaneous effect of the cladding/Zr exothermic reaction, but not necessarily a cumulative effect above approximately 973 K (700 °C). The mechanisms responsible for fission gas release events are discussed. - Highlights: •Complementary fission gas release events are reported for U-Mo fuel with and without cladding. •Exothermic reaction between Zr diffusion layer and cladding influences fission gas release. •Mechanisms responsible for fission gas release are similar, but with varying timing and magnitude. •Behavior of samples is similar after 800 °C signaling the onset of superlattice destabilization.

  1. Using Polymer Alternating Gas to Enhance Oil Recovery in Heavy Oil

    Science.gov (United States)

    Yang, Yongzhi; Li, Weirong; Zhou, Tiyao; Dong, Zhenzhen

    2018-02-01

    CO2 has been used to recover oil for more than 40 years. Currently, about 43% of EOR production in U.S. is from CO2 flooding. CO2 flooding is a well-established EOR technique, but its density and viscosity nature are challenges for CO2 projects. Low density (0.5 to 0.8 g/cm3) causes gas to rise upward in reservoirs and bypass many lower portions of the reservoir. Low viscosity (0.02 to 0.08 cp) leads to poor volumetric sweep efficiency. So water-alternating-gas (WAG) method was used to control the mobility of CO2 and improve sweep efficiency. However, WAG process has some other problems in heavy oil reservoir, such as poor mobility ratio and gravity overriding. To examine the applicability of carbon dioxide to recover viscous oil from highly heterogeneous reservoirs, this study suggests a new EOR method--polymer-alternating gas (PAG) process. The process involves a combination of polymer flooding and CO2 injection. To confirm the effectiveness of PAG process in heavy oils, a reservoir model from Liaohe Oilfield is used to compare the technical and economic performance among PAG, WAG and polymer flooding. Simulation results show that PAG method would increase oil recovery over 10% compared with other EOR methods and PAG would be economically success based on assumption in this study. This study is the first to apply PAG to enhance oil recovery in heavy oil reservoir with highly heterogeneous. Besides, this paper provides detailed discussions and comparison about PAG with other EOR methods in this heavy oil reservoir.

  2. Fission gas release during post irradiation annealing of large grain size fuels from Hinkley point B

    International Nuclear Information System (INIS)

    Killeen, J.C.

    1997-01-01

    A series of post-irradiation anneals has been carried out on fuel taken from an experimental stringer from Hinkley Point B AGR. The stringer was part of an experimental programme in the reactor to study the effect of large grain size fuel. Three differing fuel types were present in separate pins in the stringer. One variant of large grain size fuel had been prepared by using an MgO dopant during fuel manufactured, a second by high temperature sintering of standard fuel and the third was a reference, 12μm grain size fuel. Both large grain size variants had similar grain sizes around 35μm. The present experiments took fuel samples from highly rated pins from the stringer with local burn-up in excess of 25GWd/tU and annealed these to temperature of up to 1535 deg. C under reducing conditions to allow a comparison of fission gas behaviour at high release levels. The results demonstrate the beneficial effect of large grain size on release rate of 85 Kr following interlinkage. At low temperatures and release rates there was no difference between the fuel types, but at temperatures in excess of 1400 deg. C the release rate was found to be inversely dependent on the fuel grain size. The experiments showed some differences between the doped and undoped large grains size fuel in that the former became interlinked at a lower temperature, releasing fission gas at an increased rate at this temperature. At higher temperatures the grain size effect was dominant. The temperature dependence for fission gas release was determined over a narrow range of temperature and found to be similar for all three types and for both pre-interlinkage and post-interlinkage releases, the difference between the release rates is then seen to be controlled by grain size. (author). 4 refs, 7 figs, 3 tabs

  3. Fission gas release during post irradiation annealing of large grain size fuels from Hinkley point B

    Energy Technology Data Exchange (ETDEWEB)

    Killeen, J C [Nuclear Electric plc, Barnwood (United Kingdom)

    1997-08-01

    A series of post-irradiation anneals has been carried out on fuel taken from an experimental stringer from Hinkley Point B AGR. The stringer was part of an experimental programme in the reactor to study the effect of large grain size fuel. Three differing fuel types were present in separate pins in the stringer. One variant of large grain size fuel had been prepared by using an MgO dopant during fuel manufactured, a second by high temperature sintering of standard fuel and the third was a reference, 12{mu}m grain size fuel. Both large grain size variants had similar grain sizes around 35{mu}m. The present experiments took fuel samples from highly rated pins from the stringer with local burn-up in excess of 25GWd/tU and annealed these to temperature of up to 1535 deg. C under reducing conditions to allow a comparison of fission gas behaviour at high release levels. The results demonstrate the beneficial effect of large grain size on release rate of {sup 85}Kr following interlinkage. At low temperatures and release rates there was no difference between the fuel types, but at temperatures in excess of 1400 deg. C the release rate was found to be inversely dependent on the fuel grain size. The experiments showed some differences between the doped and undoped large grains size fuel in that the former became interlinked at a lower temperature, releasing fission gas at an increased rate at this temperature. At higher temperatures the grain size effect was dominant. The temperature dependence for fission gas release was determined over a narrow range of temperature and found to be similar for all three types and for both pre-interlinkage and post-interlinkage releases, the difference between the release rates is then seen to be controlled by grain size. (author). 4 refs, 7 figs, 3 tabs.

  4. Performance and heat release analysis of a pilot-ignited natural gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, S.R.; Biruduganti, M.; Mo, Y.; Bell, S.R.; Midkiff, K.C. [Alabama Univ., Dept. of Mechanical Engineering, Tuscaloosa, AL (United States)

    2002-09-01

    The influence of engine operating variables on the performance, emissions and heat release in a compression ignition engine operating in normal diesel and dual-fuel modes (with natural gas fuelling) was investigated. Substantial reductions in NO{sub x} emissions were obtained with dual-fuel engine operation. There was a corresponding increase in unburned hydrocarbon emissions as the substitution of natural gas was increased. Brake specific energy consumption decreased with natural gas substitution at high loads but increased at low loads. Experimental results at fixed pilot injection timing have also established the importance of intake manifold pressure and temperature in improving dual-fuel performance and emissions at part load. (Author)

  5. Strategies of an incumbent constrained to supply entrants: the case of European gas release programs

    International Nuclear Information System (INIS)

    Clastres, Cedric; David, Laurent

    2005-01-01

    To accelerate the development of competition in gas markets, some European regulators (in United Kingdom or in France) have decided to implement gas release programs. These programs compel the incumbent to sell gas that is no longer sold to its customers to its competitors. A first intuition would suggest that such a measure could give the incumbent an incentive to let its own costs rise in order to raise its rival's ones. With a duo-poly model, we found some cases where incentives to raise costs do exist but, in most of the cases there is no such incentives. (authors)

  6. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils

    Science.gov (United States)

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-01-01

    Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038

  7. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils.

    Science.gov (United States)

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-06-01

    Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline-alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation.

  8. Gas chromatography/sniffing port analysis of aroma compounds released under mouth conditions

    NARCIS (Netherlands)

    Ruth, van S.M.; Roozen, J.P.

    2000-01-01

    The release of aroma compounds from rehydrated French beans in an artificial mouth system and in the mouths of 12 assessors was studied by gas chromatography combined with flame ionisation detection and sniffing port detection. In an artificial mouth system, volatile compounds were isolated under

  9. Thermal ramp rate effects on mixed-oxide fuel swelling/gas release

    International Nuclear Information System (INIS)

    Hinman, C.A.; Randklev, E.H.

    1979-01-01

    Macroscopic swelling behavior of PNL-10 was compared to that of PNL-2 fuel and it was found that the swelling-threshold behavior is similar for similar thermal conditions. Transient fission gas release for the PNL-10 fuel is very similar to that observed for the PNL-2 fuel for similar thermal conditions

  10. Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

    Science.gov (United States)

    Povinelli, Louis A.

    2001-01-01

    A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

  11. Determination of Source Term for an Annual Stack Release of Gas Reactor G.A. Siwabessy

    International Nuclear Information System (INIS)

    Sudiyati; Syahrir; Unggul Hartoyo; Nugraha Luhur

    2008-01-01

    Releases of radionuclide from the reactor are noble gases, halogenides and particulates. The measurements were carried out directly on the air monitoring system of the stack. The results of these measurements are compared with the annual Source-Term data from the Safety Analyses report (SAR) of RSG-GAS. The measurement results are smaller than the data reported in SAR document. (author)

  12. Fission gas release during power change by means of re-irradiation of spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Jinichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    A full length rod irradiated at Tsuruga unit 1 was refabricated to short length rods, and rod inner pressure gauges were re-instrumented to the rods. Re-irradiation tests to study the fission gas release during power change were carried out by means of BOCA/OSF-1 facility at JMTR. In the tests, steady state operation at 40kW/m, power cycling and daily load follow operations between 20 and 40kW/m were conducted for the same high power holding time, and the rod inner pressure change during the tests was measured. The rod inner pressure increase was observed during power change, especially during power reduction. The rod inner pressure increase during a power cycling depended on the length of the high power operation just before the power cycling. The width of the rod inner pressure increase during a power cycling decreased gradually as the power cycling was repeated continuously. When steady state operation and power cycling were repeated at the power levels of 30, 35 and 40kW/m, the power cycling accelerated the fission gas release compared with the steady state operation. The fission gas release during power reduction is estimated to be the release from FP gas bubbles on the grain boundary caused by the thermal stress in the pellet during power reduction. (author)

  13. Sensitivity studies on parameters affecting gas release from an underground rock cavern

    International Nuclear Information System (INIS)

    Schlueter, E.; Pruess, K.

    1990-01-01

    A series of numerical simulation experiments is performed to quantify the effects of the release and migration of non-condensible gas in water-saturated fractured rock formations. The relative importance of multiphase parameters such as relative permeability, capillary pressure, intrinsic permeability, and porosity on system behavior is studied. 10 refs., 28 figs., 5 tabs

  14. Fission Gas Release in LWR Fuel Rods Exhibiting Very High Burn-Up

    DEFF Research Database (Denmark)

    Carlsen, H.

    1980-01-01

    Two UO2Zr BWR type test fuel rods were irradiated to a burn-up of about 38000 MWd/tUO2. After non-destructive characterization, the fission gas released to the internal free volume was extracted and analysed. The irradiation was simulated by means of the Danish fuel performance code WAFER-2, which...

  15. A gas-silicon telescope for medium-heavy ion detection

    International Nuclear Information System (INIS)

    Kozik, T.; Buschmann, J.; Neudold, M.

    1985-12-01

    A ΔE-E telescope for the identification of medium-heavy ions is presented. The specific energy loss is measured with a gas ionization chamber, and the residual energy is determined with a silicon surface barrier detector. The main features of the collecting electrical field and the timing properties of the device are discussed under theoretical aspects. The gas supply system, its electronic control unit, and the operating procedures are described. Two different versions of the coincidence electronics are shown. The experimental performance of the gas-silicon telescope is demonstrated and is found to be close to the best Z-resolution which can be obtained with this technique. (orig.) [de

  16. Reburning and burnout simulations of natural gas for heavy oil combustion

    Energy Technology Data Exchange (ETDEWEB)

    Celso A. Bertran; Carla S.T. Marques; Renato V. Filho [Universidade Estadual de Campinas, Campinas (Brazil). Instituto de Quimica

    2004-01-01

    Reburning and burnout simulations were carried out through PLUG code of CHEMKIN-III using a reduced mechanism, in order to determine preliminary experimental parameters for achieving maximum NOx reduction to implement the reburning technology for heavy oil combustion in pilot scale equipments in Brazil. Gas compositions at the entrance of the reburning zone were estimated by the AComb program. Simulations were performed for eight conditions in the usual range of operational parameters for natural gas reburning. The maximum NO reduction (ca. 50%) was reached with 10 and 17.5% of power via natural gas and 1.5 and 3.0% O{sub 2} excess, respectively, at 1273 K. The model predicts 250 ppm of NO, 50 ppm of CO and air mass flows in the range of about 50 130 kg/h for burnout. 18 refs., 1 fig., 2 tabs.

  17. Numerical algorithms for intragranular diffusional fission gas release incorporated in the Transuranus code

    International Nuclear Information System (INIS)

    Lassmann, K.

    2002-01-01

    Complicated physical processes govern diffusional fission gas release in nuclear fuels. In addition to the physical problem there exists a numerical problem, as some solutions of the underlying diffusion equation contain numerical errors that by far exceed the physical details. In this paper the two algorithms incorporated in the TRANSURANUS code, the URGAS and the new FORMAS algorithm are compared. The previously reported deficiency of the most elegant and mathematically sound FORMAS algorithm at low release could be overcome. Both algorithms are simple, fast, without numerical problems, insensitive to time step lengths and well balanced over the entire range of fission gas release. They can be made available on request as FORTRAN subroutines. (author)

  18. A description of bubble growth and gas release of helium implanted tungsten

    International Nuclear Information System (INIS)

    Sharafat, S.; Hu, Q.; Ghoniem, N.; Tkahashi, A.

    2007-01-01

    Full text of publication follows: Bubble growth and gas release during annealing of helium implanted tungsten is described using a Kinetic Monte Carlo approach. The implanted spatial profiles of stable bubble nuclei are first determined using the Kinetic Rate Theory based helium evolution code, HEROS. The effects of implantation energy, temperature, and bias forces, such as temperature- and stress gradients on bubble migration and coalescence are investigated to explain experimental gas release measurements. This comprehensive helium bubble evolution and release model, demonstrates the impact of near surface (< 1 um) versus deep helium implantation on bubble evolution. Near surface implanted helium bubbles readily attain large equilibrium sizes, while matrix bubbles remain small with high helium pressures. Using the computer simulation, the various stages of helium bubble nucleation, growth, coalescence, and migration are demonstrated and compared with available experimental results. (authors)

  19. Simulation of the thermomechanical interaction between pellet and cladding and fission gas release

    International Nuclear Information System (INIS)

    Denis, Alicia C.; Soba, Alejandro

    2000-01-01

    This paper summarizes the present status of a computer code that simulates some of the main phenomena occurring in a fuel element of a nuclear power reactor throughout its life. Temperature distribution, thermal expansion, elastic and plastic strains, creep, mechanical interaction between pellet and cladding, fission gas release, swelling and densification are modeled. Thermal expansion gives origin to elastic or plastic strains, which adequately describe the bamboo effect. The code assumes an axial symmetric rod and hence, cylindrical finite elements are employed for the discretization. The fission gas inventory is calculated by means of a diffusion model, which assumes spherical grains and uses also a finite element scheme. Once the temperature distribution in the pellet and the cladding is obtained and in order to reduce the calculation time, the rod is divided into five cylindrical rings where the temperature is averaged. In each ring the gas diffusion problem is solved in one representative grain and the results are then extended to the whole ring. The pressure, increased by the released gas, interacts with the stress field. Densification and swelling due to solid and gaseous fission products are also considered. Experiments, particularly those of the FUMEX series, are simulated with this code. A good agreement is obtained for the fuel center line temperature, the inside rod pressure and the fractional gas release. (author)

  20. Simulation of pellet-cladding thermomechanical interaction and fission gas release

    International Nuclear Information System (INIS)

    Denis, A.; Soba, A.

    2001-01-01

    This paper summarizes the present status of a computer code that describes some of the main phenomena occurring in a nuclear fuel element throughout its life. Temperature distribution, thermal expansion, elastic and plastic strains, creep, mechanical interaction between pellet and cladding, fission gas release, swelling and densification are modelized. The code assumes an axi-symmetric rod and hence, cylindrical finite elements are employed for the discretization. Due to the temperature dependence of the thermal conductivity, the heat conduction problem is non-linear. Thermal expansion gives origin to elastic or plastic strains, which adequately describe the bamboo effect. Plasticity renders the stress-strain problem non linear. The fission gas inventory is calculated by means of a diffusion model, which assumes spherical grains and uses a finite element scheme. In order to reduce the calculation time, the rod is divided into five cylindrical rings where the temperature is averaged. In each ring the gas diffusion problem is solved in one grain and the results are then extended to the whole ring. The pressure, increased by the released gas, interacts with the stress field. Densification and swelling due to solid and gaseous fission products are also considered. Experiments, particularly those of the FUMEX series, are simulated with this code. A good agreement is obtained for the fuel center line temperature, the inside rod pressure and the fractional gas release. (author)

  1. On the fission gas release from oxide fuels during normal grain growth

    International Nuclear Information System (INIS)

    Paraschiv, M.C.; Paraschiv, A.; Glodeanu, F.

    1997-01-01

    A mathematical formalism for calculating the fission gas release from oxide fuels considering an arbitrary distribution of fuel grain size with only zero boundary condition for gas diffusion at the grain boundary is proposed. It has also been proved that it becomes unnecessary to consider the grain volume distribution function for fission products diffusion when the grain boundary gas resolution is considered, if thermodynamic forces on grain boundaries are only time dependent. In order to highlight the effect of the normal grain growth on fission gas release from oxide fuels Hillert's and Lifshitz and Slyozov's theories have been selected. The last one was used to give an adequate treatment of normal grain growth for the diffusion-controlled grain boundary movement in oxide fuels. It has been shown that during the fuel irradiation, the asymptotic form of the grain volume distribution functions given by Hillert and Lifshitz and Slyozov models can be maintained but the grain growth rate constant becomes time dependent itself. Experimental results have been used to correlate the two theoretical models of normal grain growth to the fission gas release from oxide fuels. (orig.)

  2. PolyPole-1: An accurate numerical algorithm for intra-granular fission gas release

    International Nuclear Information System (INIS)

    Pizzocri, D.; Rabiti, C.; Luzzi, L.; Barani, T.; Van Uffelen, P.; Pastore, G.

    2016-01-01

    The transport of fission gas from within the fuel grains to the grain boundaries (intra-granular fission gas release) is a fundamental controlling mechanism of fission gas release and gaseous swelling in nuclear fuel. Hence, accurate numerical solution of the corresponding mathematical problem needs to be included in fission gas behaviour models used in fuel performance codes. Under the assumption of equilibrium between trapping and resolution, the process can be described mathematically by a single diffusion equation for the gas atom concentration in a grain. In this paper, we propose a new numerical algorithm (PolyPole-1) to efficiently solve the fission gas diffusion equation in time-varying conditions. The PolyPole-1 algorithm is based on the analytic modal solution of the diffusion equation for constant conditions, combined with polynomial corrective terms that embody the information on the deviation from constant conditions. The new algorithm is verified by comparing the results to a finite difference solution over a large number of randomly generated operation histories. Furthermore, comparison to state-of-the-art algorithms used in fuel performance codes demonstrates that the accuracy of PolyPole-1 is superior to other algorithms, with similar computational effort. Finally, the concept of PolyPole-1 may be extended to the solution of the general problem of intra-granular fission gas diffusion during non-equilibrium trapping and resolution, which will be the subject of future work. - Highlights: • A new numerical algorithm (PolyPole-1) for intra-granular fission gas release in time-varying conditions is developed. • The concept combines the modal analytic solution for constant conditions and a polynomial correction. • PolyPole-1 is extensively verified and compared to other state-of-the-art algorithms. • PolyPole-1 exhibits a superior accuracy and a similar computational time relative to other algorithms. • The PolyPole-1 algorithm can be

  3. PolyPole-1: An accurate numerical algorithm for intra-granular fission gas release

    Energy Technology Data Exchange (ETDEWEB)

    Pizzocri, D. [Politecnico di Milano, Department of Energy, Nuclear Engineering Division, Via La Masa 34, 20156 Milano (Italy); Rabiti, C. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Luzzi, L.; Barani, T. [Politecnico di Milano, Department of Energy, Nuclear Engineering Division, Via La Masa 34, 20156 Milano (Italy); Van Uffelen, P. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Pastore, G., E-mail: giovanni.pastore@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States)

    2016-09-15

    The transport of fission gas from within the fuel grains to the grain boundaries (intra-granular fission gas release) is a fundamental controlling mechanism of fission gas release and gaseous swelling in nuclear fuel. Hence, accurate numerical solution of the corresponding mathematical problem needs to be included in fission gas behaviour models used in fuel performance codes. Under the assumption of equilibrium between trapping and resolution, the process can be described mathematically by a single diffusion equation for the gas atom concentration in a grain. In this paper, we propose a new numerical algorithm (PolyPole-1) to efficiently solve the fission gas diffusion equation in time-varying conditions. The PolyPole-1 algorithm is based on the analytic modal solution of the diffusion equation for constant conditions, combined with polynomial corrective terms that embody the information on the deviation from constant conditions. The new algorithm is verified by comparing the results to a finite difference solution over a large number of randomly generated operation histories. Furthermore, comparison to state-of-the-art algorithms used in fuel performance codes demonstrates that the accuracy of PolyPole-1 is superior to other algorithms, with similar computational effort. Finally, the concept of PolyPole-1 may be extended to the solution of the general problem of intra-granular fission gas diffusion during non-equilibrium trapping and resolution, which will be the subject of future work. - Highlights: • A new numerical algorithm (PolyPole-1) for intra-granular fission gas release in time-varying conditions is developed. • The concept combines the modal analytic solution for constant conditions and a polynomial correction. • PolyPole-1 is extensively verified and compared to other state-of-the-art algorithms. • PolyPole-1 exhibits a superior accuracy and a similar computational time relative to other algorithms. • The PolyPole-1 algorithm can be

  4. Gas generation in SFL 3-5 and effects on radionuclide release

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, K.; Lindgren, M.; Pers, K. [Kemakta Konsult AB, Stockholm (Sweden)

    1999-12-01

    A deep repository, SFL 3-5, is presently planned for disposing of long-lived low- and intermediate-level waste. In this study the amounts of gas that can be generated in the waste packages and in the vaults are estimated. The potential gas pressure build-up, the displacement of contaminated water and the consequences on radionuclide release from the engineered barriers in the repository are also addressed. The study is focussed on the repository design and waste inventory that was defined for the prestudy of SFL 3-5. Since the reporting of the prestudy the design of the repository has been modified and the waste inventory has been updated and a preliminary safety assessment of the repository has been carried outbased on the new design and updated waste inventory. The implications on gas generation and release of these modifications in design and waste inventory are briefly addressed in this study.

  5. Gas generation in SFL 3-5 and effects on radionuclide release

    International Nuclear Information System (INIS)

    Skagius, K.; Lindgren, M.; Pers, K.

    1999-12-01

    A deep repository, SFL 3-5, is presently planned for disposing of long-lived low- and intermediate-level waste. In this study the amounts of gas that can be generated in the waste packages and in the vaults are estimated. The potential gas pressure build-up, the displacement of contaminated water and the consequences on radionuclide release from the engineered barriers in the repository are also addressed. The study is focussed on the repository design and waste inventory that was defined for the prestudy of SFL 3-5. Since the reporting of the prestudy the design of the repository has been modified and the waste inventory has been updated and a preliminary safety assessment of the repository has been carried out based on the new design and updated waste inventory. The implications on gas generation and release of these modifications in design and waste inventory are briefly addressed in this study

  6. Efficient inhibition of heavy metal release from mine tailings against acid rain exposure by triethylenetetramine intercalated montmorillonite (TETA-Mt).

    Science.gov (United States)

    Gong, Beini; Wu, Pingxiao; Huang, Zhujian; Li, Yuanyuan; Yang, Shanshan; Dang, Zhi; Ruan, Bo; Kang, Chunxi

    2016-11-15

    The potential application of triethylenetetramine intercalated montmorillonite (TETA-Mt) in mine tailings treatment and AMD (acid mine drainage) remediation was investigated with batch experiments. The structural and morphological characteristics of TETA-Mt were analyzed with XRD, FTIR, DTG-TG and SEM. The inhibition efficiencies of TETA-Mt against heavy metal release from mine tailings when exposed to acid rain leaching was examined and compared with that of triethylenetetramine (TETA) and Mt. Results showed that the overall inhibition by TETA-Mt surpassed that by TETA or Mt for various heavy metal ions over an acid rain pH range of 3-5.6 and a temperature range of 25-40°C. When mine tailings were exposed to acid rain of pH 4.8 (the average rain pH of the mining site where the mine tailings were from), TETA-Mt achieved an inhibition efficiency of over 90% for Cu(2+), Zn(2+), Cd(2+) and Mn(2+) release, and 70% for Pb(2+) at 25°C. It was shown that TETA-Mt has a strong buffering capacity. Moreover, TETA-Mt was able to adsorb heavy metal ions and the adsorption process was fast, suggesting that coordination was mainly responsible. These results showed the potential of TETA-Mt in AMD mitigation, especially in acid rain affected mining area. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. GRASS-SST, Fission Products Gas Release and Fuel Swelling in Steady-State and Transients

    International Nuclear Information System (INIS)

    Zawadzki, S.

    2001-01-01

    1 - Description of program or function: GRASS-SST is a comprehensive, mechanistic model for the prediction of fission-gas behaviour in UO 2 -base fuels during steady-state and transient conditions. GRASS-SST treats fission-gas release and fuel swelling on an equal basis and simultaneously treats all major mechanisms that influence fission-gas behaviour. Models are included for intra- and inter-granular fission-gas bubble behaviour as well as a mechanistic description of the role of grain-edge inter-linked porosity on fission-gas release and swelling. GRASS-SST calculations include the effects of gas production from fissioning uranium atoms, bubble nucleation, a realistic equation of state for xenon, lattice bubble diffusivities based on experimental observations, bubble migration, bubble coalescence, re-solution, temperature and temperature gradients, inter-linked porosity, and fission-gas interaction with structural defects (dislocations and grain boundaries) on both the distribution of fission-gas within the fuel and on the amount of fission-gas released from the fuel. GRASS-SST includes the effects of the degree of nonequilibrium in the UO 2 lattice on fission-gas bubble mobility and bubble coalescence and also accounts for the observed formation of grain-surface channels. GRASS-SST also includes mechanistic models for grain-growth/grain boundary sweeping and for the behaviour of fission gas during liquefaction/dissolution and fuel melting conditions. 2 - Method of solution: A system of coupled equations for the evolution of the fission-gas bubble-size distributions in the lattice, on dislocations, on grain faces, and grain edges is derived based on the GRASS-SST models. Given a set of operating conditions, GRASS-SST calculates the bubble radii for the size classes of bubbles under consideration using a realistic equation of state for xenon as well as a generalised capillary relation. 3 - Restrictions on the complexity of the problem: Maxima of : 1 axial section

  8. Fission gas and iodine release measured up to 15 GWd/t UO2 burnup

    International Nuclear Information System (INIS)

    Appelhans, A.D.

    1983-01-01

    A summary is presented of the measured release of xenon, krypton and iodine up to 15 GWd/t UO 2 burnup for fuel centerline temperatures ranging from 950 to 1800 K, at average linear heat ratings of 15 to 35 kW/m. The IFA-430 is composed of four 1.28-m-long fuel rods containing 10% enriched UO 2 pellet fuel. Two of the fuel rods are connected, top and bottom, to a gas flow system that permits the fission gases released from the fuel pellets to be swept out of the rods during irradiation and measured via gamma spectrometry. The release/burnup increased significantly between 10 and 15 GWd/t burnup. Fuel temperature did not change. Increased releases were due to physical changes in the fuel-surface area. Changes appeared to be due to higher power operation and burnup

  9. Use of a levonorgestrel-releasing intrauterine device in the treatment of adenomyosis associated heavy menstrual bleeding

    International Nuclear Information System (INIS)

    Uysal, A.; Taner, C.E.; Mun, S.; Celimli, F.H.; Uysal, F.

    2013-01-01

    To evaluate the effects of a levonorgestrel-releasing intrauterine device in the treatment of adenomyosis associated with heavy menstrual bleeding. Methods: The retrospective study was conducted at a tertiary referral hospital in Izmir, Turkey, and comprised data on adenomyosis patients who were implanted with a levonorgestrel-releasing intrauterine device for heavy menstrual bleeding between December 2004 and January 2008. After the insertion of the device, all patients were followed up by transvaginal ultrasonography and serum haemoglobin levels and menstrual patterns were determined at the 6th and 12th month. Data was analysed using SPSS 10. Results: The mean age of the 42 women in the study was 43.2+-0.8 years. At the sixth month, amenorrhoea, oligomenorrhoea, spotting and regular menstrual flow were 9.5% (n=4), 7% (n=3), 19% (n=8), and 64% (n=27), respectively. At the 12th month, the same parametres were 9.5% (n=4), 7% (n=3), 12% (n=5), and 71% (n=30), respectively. Haemoglobin levels had increased and endometrial thickness had decreased, and these differences were statistically significant (p<0.001). Conclusion: The easy-to-use levonorgestrel-releasing intrauterine device can be added to the treatment options as a well-tolerated alternative in cases where a woman who has completed her fertility and does not request a hysterectomy has anaemia associated with adenomyosis. (author)

  10. Acoustic sensor for in-pile fuel rod fission gas release measurement

    International Nuclear Information System (INIS)

    Fourmentel, D.; Villard, J. F.; Ferrandis, J. Y.; Augereau, F.; Rosenkrantz, E.; Dierckx, M.

    2009-01-01

    We have developed a specific acoustic sensor to improve the knowledge of fission gas release in Pressurized Water Reactor (PWR) fuel rods when irradiated in materials testing reactors. In order to perform experimental programs related to the study of the fission gas release kinetics, the CEA (French Nuclear Energy Commission) acquired the ability to equip a pre-irradiated PWR fuel rod with three sensors, allowing the simultaneous on-line measurements of the following parameters: - fuel temperature with a centre-line thermocouple type C, - internal pressure with a specific counter-pressure sensor, - fraction of fission gas released in the fuel rod with an innovative acoustic sensor. The third detector is the subject of this paper. This original acoustic sensor has been designed to measure the molar mass and pressure of the gas contained in the fuel rod plenum. For in-pile instrumentation, the fraction of fission gas, such as Krypton and Xenon, in Helium, can be deduced online from this measurement. The principle of this acoustical sensor is the following: a piezoelectric transducer generates acoustic waves in a cavity connected to the fuel rod plenum. The acoustic waves are propagated and reflected in this cavity and then detected by the transducer. The data processing of the signal gives the velocity of the acoustic waves and their amplitude, which can be related respectively to the molar mass and to the pressure of the gas. The piezoelectric material of this sensor has been qualified in nuclear conditions (gamma and neutron radiations). The complete sensor has also been specifically designed to be implemented in materials testing reactors conditions. For this purpose some technical points have been studied in details: - fixing of the piezoelectric sample in a reliable way with a suitable signal transmission, - size of the gas cavity to avoid any perturbation of the acoustic waves, - miniaturization of the sensor because of narrow in-pile experimental devices

  11. Increasing of MERARG experimental performances: on-line fission gas release measurement by mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pontillon, Y.; Capdevila, H.; Clement, S. [CEA, DEN, DEC, SA3C, LAMIR, F-13108 Saint Paul lez Durance, (France); Guigues, E.; Janulyte, A.; Zerega, Y.; Andre, J. [Aix-Marseille Universite, LISA EA 4672, 13397 MARSEILLE cedex 20, (France)

    2015-07-01

    The MERARG device - implemented at the LECASTAR Hot Laboratory, at the CEA Cadarache - allows characterizing nuclear fuels with respect to the behaviour of fission gases during thermal transients representative of normal or off normal operating nuclear power plant conditions. The fuel is heated in order to extract a part or the total gas inventory it contains. Fission Gas Release (FGR) is actually recorded by mean of both on-line gamma spectrometry station and micro gas chromatography. These two devices monitor the quantity and kinetics of fission gas release rate. They only address {sup 85}Kr radioactive isotope and the elemental quantification of Kr, Xe and He (with a relatively low detection limit in the latter case, typically 5-10 ppm). In order to better estimate the basic mechanisms that promote fission gas release from irradiated nuclear fuels, the CEA fuel study department decided to improve its experimental facility by modifying MERARG to extend the studies of gamma emitter fission gases to all gases (including Helium) with a complete isotopic distribution capability. To match these specifications, a Residual Gas Analyser (RGA) has been chosen as mass spectrometer. This paper presents a review of the main aspects of the qualification/calibration phase of the RGA type analyser. In particular, results recorded over three mass ranges 1-10 u, 80-90 u and 120-140 u in the two classical modes of MERARG, i.e. on-line and off-line measurements are discussed. Results obtained from a standard gas bottle show that the quantitative analysis at a few ppm levels can be achieved for all isotopes of Kr and Xe, as well as masses 2 and 4 u. (authors)

  12. Novel Solid Encapsulation of Ethylene Gas Using Amorphous α-Cyclodextrin and the Release Characteristics.

    Science.gov (United States)

    Ho, Binh T; Bhandari, Bhesh R

    2016-05-04

    This research investigated the encapsulation of ethylene gas into amorphous α-cyclodextrins (α-CDs) at low (LM) and high (HM) moisture contents at 1.0-1.5 MPa for 24-120 h and its controlled release characteristics at 11.2-52.9% relative humidity (RH) for 1-168 h. The inclusion complexes (ICs) were characterized using X-ray diffractometry (XRD), nuclear magnetic resonance spectroscopy (CP-MAS (13)C NMR), and scanning electron microscopy (SEM). Ethylene concentrations in the ICs were from 0.45 to 0.87 mol of ethylene/mol CD and from 0.42 to 0.54 mol of ethylene/mol CD for LM and HM α-CDs, respectively. Ethylene gas released from the encapsulated powder at higher rates with increasing RH. An analysis of release kinetics using Avrami's equation showed that the LM and HM amorphous α-CDs were not associated with significant differences in release constant k and parameter n for any given RH condition. NMR spectra showed the presence of the characteristic carbon-carbon double bond of ethylene gas in the encapsulated α-CD powder.

  13. Analysis of fuel centre temperatures and fission gas release data from the IFPE Database

    International Nuclear Information System (INIS)

    Schubert, A.; Lassmann, K.; Van Uffelen, P.; Van de Laar, J.; Elenkov, D.; Asenov, S.; Boneva, S.; Djourelov, N.; Georgieva, M.

    2003-01-01

    The present work has continued the analysis of fuel centre temperatures and fission gas release, calculated with standard options of the TRANSURANUS code. The calculations are compared to experimental data from the International Fuel Performance Experiments (IFPE) database. It is reported an analysis regarding UO 2 fuel for Western-type reactors: Fuel centre temperatures measured in the experiments Contact 1 and Contact 2 (in-pile tests of 2 rods performed at the Siloe reactor in Grenoble, France, closely simulating commercial PWR conditions); Fission gas release data derived from post-irradiation examinations of 9 fuel rods belonging to the High-Burnup Effects Programme, task 3 (HBEP3). The results allow for a comparison of predictions by TRANSURANUS for the mentioned Western-type fuels with those done previously for Russian-type WWER fuel. The comparison has been extended to include fuel centre temperatures as well as fission gas release. The present version of TRANSURANUS includes a model that calculates the production of Helium. The amount of produced Helium is compared to the measured and to the calculated release of the fission gases Xenon and Krypton

  14. 76 FR 65971 - Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty...

    Science.gov (United States)

    2011-10-25

    ... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration 49 CFR Parts 523 and 535 [NHTSA 2010-0079; EPA-HQ-OAR-2010-0162; FRL-9455-1] RIN 2127-AK74 Greenhouse Gas Emissions... fuel efficiency and reduce greenhouse gas emissions for on-road heavy-duty vehicles, responding to the...

  15. 76 FR 59922 - Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty...

    Science.gov (United States)

    2011-09-28

    ... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration 49 CFR Part 535 [NHTSA 2010-0079; EPA-HQ-OAR-2010-0162; FRL-9455-1] RIN 2127-AK74 Greenhouse Gas Emissions Standards and Fuel... comprehensive Heavy-Duty National Program that will increase fuel efficiency and reduce greenhouse gas emissions...

  16. Hot Experiment on Fission Gas Release Behavior from Voloxidation Process using Spent Fuel

    International Nuclear Information System (INIS)

    Park, Geun Il; Park, J. J.; Jung, I. H.; Shin, J. M.; Cho, K. H.; Yang, M. S.; Song, K. C.

    2007-08-01

    Quantitative analysis of the fission gas release characteristics during the voloxidation and OREOX processes of spent PWR fuel was carried out by spent PWR fuel in a hot-cell of the DFDF. The release characteristics of 85 Kr and 14 C fission gases during voloxidation process at 500 .deg. C is closely linked to the degree of conversion efficiency of UO 2 to U 3 O 8 powder, and it can be interpreted that the release from grain-boundary would be dominated during this step. Volatile fission gases of 14 C and 85 Kr were released to near completion during the OREOX process. Both the 14 C and 85 Kr have similar release characteristics under the voloxidation and OREOX process conditions. A higher burn-up spent fuel showed a higher release fraction than that of a low burn-up fuel during the voloxidation step at 500 .deg. C. It was also observed that the release fraction of semi-volatile Cs was about 16% during a reduction at 1,000 .deg. C of the oxidized powder, but over 90% during the voloxidation at 1,250 .deg. C

  17. Environmental release of carbon-14 gas from a hypothetical nuclear waste repository

    International Nuclear Information System (INIS)

    Lehto, M.A.; Merrell, G.B.

    1994-01-01

    Radioisotopes may form gases in a spent nuclear fuel waste package due to elevated temperatures or degradation of the fuel rods. Radioactive carbon-14, as gaseous carbon dioxide, is one of the gaseous radioisotopes of concern at an underground disposal facility for spent nuclear fuel and high-level radioactive waste. Carbon-14 dioxide may accumulate inside an intact waste container. Upon breach of the container, a potentially large pulse of carbon-14 dioxide gas may be released to the surrounding environment, followed by a lower, long-term continuous release. If the waste were disposed of in an unsaturated geologic environment, the carbon-14 gas would begin to move through the unsaturated zone to the accessible environment. This study investigates the transport of radioactive carbon-14 gas in geologic porous media using a one-dimensional analytical solution. Spent nuclear fuel emplaced in a deep geologic repository located at a generic unsaturated tuff site is analyzed. The source term for the carbon-14 gas and geologic parameters was obtained from previously published materials. The one-dimensional analytical solution includes diffusion, advection, radionuclide retardation, and radioactive decay terms. Two hypothetical sites are analyzed. One is dominated by advective transport, and the other is dominated by diffusive transport. The dominant transport mechanism at an actual site depends on the site characteristics. Results from the simulations include carbon-14 dioxide travel times to the accessible environment and the total release to the environment over a 10,000-year period. The results are compared to regulatory criteria

  18. A fission gas release model for MOX fuel and its verification

    International Nuclear Information System (INIS)

    Koo, Y.H.; Sohn, D.S.; Strijov, P.

    2000-01-01

    A fission gas release model for MOX fuel has been developed based on a model for UO 2 fuel. Using the concept of equivalent cell, the model considers the uneven distribution of Pu within the fuel matrix and a number of Pu-rich particles that could lead to a non-uniform fission rate and fission gas distribution across the fuel pellet. The model has been incorporated into a code, COSMOS, and some parametric studies were made to analyze the effect of the size and Pu content of Pu-rich agglomerates. The model was then applied to the experimental data obtained from the FIGARO program, which consisted of the base irradiation of MOX fuels in the BEZNAU-1 PWR and the subsequent irradiation of four refabricated fuel segments in the Halden reactor. The calculated gas releases show good agreement with the measured ones. In addition, the present analysis indicates that the microstructure of the MOX fuel used in the FIGARO program is such that it has produced little difference in terms of gas release compared with UO 2 fuel. (author)

  19. An evaluation of gas release modelling approaches as to their applicability in fuel behaviour models

    International Nuclear Information System (INIS)

    Mattila, L.J.; Sairanen, R.T.

    1980-01-01

    The release of fission gas from uranium oxide fuel to the voids in the fuel rod affects in many ways the behaviour of LWR fuel rods both during normal operating conditions including anticipated transients and during off-normal and accident conditions. The current trend towards significantly increased discharge burnup of LWR fuel will increase the importance of fission gas release considerations both from the design and safety viewpoints. In the paper fission gas release models are classified to 5 categories on the basis of complexity and physical sophistication. For each category, the basic approach common to the models included in the category is described, a few representative models of the category are singled out and briefly commented in some cases, the advantages and drawbacks of the approach are listed and discussed and conclusions on the practical feasibility of the approach are drawn. The evaluation is based on both literature survey and our experience in working with integral fuel behaviour models. The work has included verification efforts, attempts to improve certain features of the codes and engineering applications. The classification of fission gas release models regarding their applicability in fuel behaviour codes can of course be done only in a coarse manner. The boundaries between the different categories are vague and a model may be well refined in a way which transfers it to a higher category. Some current trends in fuel behaviour research are discussed which seem to motivate further extensive efforts in fission product release modelling and are certain to affect the prioritizing of the efforts. (author)

  20. Improvements in gas supply systems for heavy-water moderated reactors

    International Nuclear Information System (INIS)

    Aubert, G.; Hassig, J.M.; Laurent, N.; Thomas, B.

    1964-01-01

    In a heavy-water moderated reactor cooled by pressurized gas, an important problem from the point of view, of the reactor block and its economics is the choice of the gas supply system. In the pressure tube solution, the whole of the reactor block structure is at a relatively low temperature, whereas the gas supply equipment is at that of the gas, which is much higher. These parts, through which passes the heat carrying fluid have to present as low a resistance as possible to it so as to avoid costly extra blowing power. Finally, they may only be placed in the reactor block after it has been built; the time required for putting them in position should therefore not be too long. The work reported here concerns the various problems arising in the case of each channel being supplied individually by a tube at the entry and the exit which is connected to a main circuit made up of large size collectors. This individual tubing is sufficiently flexible to absorb the differential expansion and the movement of its ends without stresses or prohibitive reactions being produced; the tubing is also of relatively short length so as to reduce the pressure head of the pressurized gas outside the channels; the small amount of space taken up by the tubing makes it possible to assemble it in a manner which is satisfactory from the point of view both of the time required and of the technical quality. (authors) [fr

  1. Development of a Time Projection Chamber using CF4 gas for relativistic heavy ion experiments

    International Nuclear Information System (INIS)

    Isobe, T.; Hamagaki, H.; Ozawa, K.; Inuzuka, M.; Sakaguchi, T.; Matsumoto, T.; Kametani, S.; Kajihara, F.; Gunji, T.; Kurihara, N.; Oda, S.X.; Yamaguchi, Y.L.

    2006-01-01

    A prototype Time Projection Chamber (TPC) using pure CF 4 gas was developed for possible use in heavy ion experiments. Basic characteristics such as gain, drift velocity, longitudinal diffusion and attenuation length of produced electrons were measured with the TPC. At an electric field of 900V/cm, the drift velocity and longitudinal diffusion for 1cm drift were obtained as 10cm/μs and 60μm, respectively. The relatively large gain fluctuation is explained to be due to the electron attachment process in CF 4 . These characteristics are encouraging for the measurement of the charged particle trajectories under high multiplicity conditions at RHIC

  2. The application of release models to the interpretation of rare gas coolant activities

    International Nuclear Information System (INIS)

    Wise, C.

    1985-01-01

    Much research is carried out into the release of fission products from UO 2 fuel and from failed pins. A significant application of this data is to define models of release which can be used to interpret measured coolant activities of rare gas isotopes. Such interpretation is necessary to extract operationally relevant parameters, such as the number and size of failures in the core and the 131 I that might be released during depressurization faults. The latter figure forms part of the safety case for all operating CAGRs. This paper describes and justifies the models which are used in the ANAGRAM program to interpret CAGR coolant activities, highlighting any remaining uncertainties. The various methods by which the program can extract relevant information from the measurements are outlined, and examples are given of the analysis of coolant data. These analyses point to a generally well understood picture of fission gas release from low temperature failures. Areas of higher temperature release are identified where further research would be beneficial to coolant activity analysis. (author)

  3. Gas release and leachates at bark storage: Laboratory and field studies. Final report

    International Nuclear Information System (INIS)

    Jirjis, Raida; Andersson, Paal; Aronsson, Paer

    2005-01-01

    Large volumes of bark are produced as a by-product from saw mills and pulp and paper industry all year round in Sweden. Most of the bark is used as a biofuel. Due to the uneven demand for the fuel during the year, bark has to be often stored for a few months. Storage normally takes place outdoors in fairly large piles. A number of biological and chemical processes are known to occur during storage. These processes can lead to the emission and leakage of environmentally unaccepted products which can also affect working environment. The aim of this project was to evaluate the outcome of some of these processes and to asses its effect on working environment as well as the surrounding environment. This study investigates the storage of fresh bark from pine and spruce in laboratory scale experiments and a large scale storage trial. Results of the analyses of bark material, before and after storage, and the chemical constituents of the released gases and leached material are presented. Estimation of the total amounts that can be released in gas form or leached out from bark piles during storage, and possible environmental consequences are discussed. Conclusions and some practical suggestion concerning bark storage are given in this report. The laboratory experiment involved storage of fresh bark in a 34 litres cylindrical chamber at room temperature (RT) or heated to an average of 55 deg C. The chambers were designed to provide gas samples during emissions experiment and allow irrigation during leakage experiments. Sampling of the released gases (using Tenax-adsorbent) was performed during two or three weeks of storage for spruce and pine bark respectively. The total volatile organic compounds (VOC) and individual monoterpenes were determined. Changes in the chemical constituents of bark during storage were studied using different extraction methods and measuring instruments including Gas spectroscopy (GC)-flame ionization detector (FID) and GC- mass spectroscopy (MS

  4. Conditions for the formation and atmospheric dispersion of a toxic, heavy gas layer during thermal metamorphism of coal and evaporite deposits by sill intrusion

    Science.gov (United States)

    Storey, Michael; Hankin, Robin K. S.

    2010-05-01

    There is compelling evidence for massive discharge of volatiles, including toxic species, into the atmosphere at the end of the Permian. It has been argued that most of the gases were produced during thermal metamorphism of coal and evaporite deposits in the East Siberia Tunguska basin following sill intrusion (Retallack and Jahren, 2008; Svensen et al., 2009). The release of the volatiles has been proposed as a major cause of environmental and extinction events at the end of the Permian, with venting of carbon gases and halocarbons to the atmosphere leading to global warming and atmospheric ozone depletion (Svensen et al., 2009) Here we consider the conditions required for the formation and dispersion of toxic, heavier than air, gas plumes, made up of a mixture of CO2, CH4, H2S and SO2 and formed during the thermal metamorphism of C- and S- rich sediments. Dispersion models and density considerations within a range of CO2/CH4 ratios and volatile fluxes and temperatures, for gas discharge by both seepage and from vents, allow the possibility that following sill emplacement much of the vast East Siberia Tunguska basin was - at least intermittently - covered by a heavy, toxic gas layer that was unfavorable for life. Dispersion scenarios for a heavy gas layer beyond the Siberian region during end-Permian times will be presented. REFERENCES G. J. Retallack and A. H. Jahren, Methane release from igneous intrusion of coal during Late Permian extinction events, Journal of Geology, volume 116, 1-20, 2008 H. Svensen et al., Siberian gas venting and the end-Permian environmental crisis, Earth and Planetary Science Letters, volume 277, 490-500, 2009

  5. Pressure pulses generated by gas released from a breached fuel element

    International Nuclear Information System (INIS)

    Wu, T.S.

    1979-01-01

    In experimental measurements of liquid pressure pulses generated by rapid release of gas from breached fuel elements in a nuclear reactor, different peak pressures were observed at locations equidistant from the origin of the release. Using the model of a submerged spherical bubble with a nonstationary center, this analysis predicts not only that the peak pressure would be higher at a point in front of the advancing bubble than that at a point the same distance behind the bubble origin, but also that the pressure pulse in front of the bubble reaches its peak later than the pulse behind the origin

  6. IFPE/RISOE-II, Fuel Performance Data from Transient Fission Gas Release

    International Nuclear Information System (INIS)

    Turnbull, J.A.

    1995-01-01

    Description: The RISO National Laboratory in Denmark have carried out three irradiation programs of slow ramp and hold tests, so called 'bump tests' to investigate fission gas release and fuel microstructural changes. The second project took place between 1982 and 1986 and was called 'The RISO Transient Fission Gas Project'. The fuel used in the project was from: IFA-161 irradiated in the Halden BWR (27 to 42 MWd/kgUO 2 ) and GE BWR fuel irradiated in the Millstone 1 reactor 14 to 29 MWd/kgUO 2 . Using the re-fabrication technique, it was possible to back fill the test segment with a choice of gas and gas pressure and to measure the time dependence of fission gas release by continuous monitoring of the plenum pressure. The short length of the test segment was an advantage because, depending on where along the original rod the section was taken, burnup could be chosen variable, and during the test the fuel experienced a single power

  7. Non-Volcanic release of CO2 in Italy: quantification, conceptual models and gas hazard

    Science.gov (United States)

    Chiodini, G.; Cardellini, C.; Caliro, S.; Avino, R.

    2011-12-01

    Central and South Italy are characterized by the presence of many reservoirs naturally recharged by CO2 of deep provenance. In the western sector, the reservoirs feed hundreds of gas emissions at the surface. Many studies in the last years were devoted to (i) elaborating a map of CO2 Earth degassing of the region; (ii) to asses the gas hazard; (iii) to develop methods suitable for the measurement of the gas fluxes from different types of emissions; (iv) to elaborate the conceptual model of Earth degassing and its relation with the seismic activity of the region and (v) to develop physical numerical models of CO2 air dispersion. The main results obtained are: 1) A general, regional map of CO2 Earth degassing in Central Italy has been elaborated. The total flux of CO2 in the area has been estimated in ~ 10 Mt/a which are released to the atmosphere trough numerous dangerous gas emissions or by degassing spring waters (~ 10 % of the CO2 globally estimated to be released by the Earth trough volcanic activity). 2) An on line, open access, georeferenced database of the main CO2 emissions (~ 250) was settled up (http://googas.ov.ingv.it). CO2 flux > 100 t/d characterise 14% of the degassing sites while CO2 fluxes from 100 t/d to 10 t/d have been estimated for about 35% of the gas emissions. 3) The sites of the gas emissions are not suitable for life: the gas causes many accidents to animals and people. In order to mitigate the gas hazard a specific model of CO2 air dispersion has been developed and applied to the main degassing sites. A relevant application regarded Mefite d'Ansanto, southern Apennines, which is the largest natural emission of low temperature CO2 rich gases, from non-volcanic environment, ever measured in the Earth (˜2000 t/d). Under low wind conditions, the gas flows along a narrow natural channel producing a persistent gas river which has killed over a period of time many people and animals. The application of the physical numerical model allowed us to

  8. Greenhouse gas emissions from heavy-duty natural gas, hybrid, and conventional diesel on-road trucks during freight transport

    Science.gov (United States)

    Quiros, David C.; Smith, Jeremy; Thiruvengadam, Arvind; Huai, Tao; Hu, Shaohua

    2017-11-01

    Heavy-duty on-road vehicles account for 70% of all freight transport and 20% of transportation-sector greenhouse gas (GHG) emissions in the United States. This study measured three prevalent GHG emissions - carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) - from seven heavy-duty vehicles, fueled by diesel and compressed natural gas (CNG), and compliant to the MY 2007 or 2010 U.S. EPA emission standards, while operated over six routes used for freight movement in California. Total combined (tractor, trailer, and payload) weights were 68,000 ± 1000 lbs. for the seven vehicles. Using the International Panel on Climate Change (IPCC) radiative forcing values for a 100-year time horizon, N2O emissions accounted for 2.6-8.3% of total tailpipe CO2 equivalent emissions (CO2-eq) for diesel vehicles equipped with Diesel Oxidation Catalyst, Diesel Particulate Filter, and Selective Catalytic Reduction system (DOC + DPF + SCR), and CH4 emissions accounted for 1.4-5.9% of CO2-eq emissions from the CNG-powered vehicle with a three-way catalyst (TWC). N2O emissions from diesel vehicles equipped with SCR (0.17-0.30 g/mi) were an order of magnitude higher than diesel vehicles without SCR (0.013-0.023 g/mi) during highway operation. For the vehicles selected in this test program, we measured 11-22% lower CO2-eq emissions from a hybrid compared to conventional diesel vehicles during transport over lower-speed routes of the freight transport system, but 20-27% higher CO2-eq emissions during higher-speed routes. Similarly, a CNG vehicle emitted up to 15% lower CO2-eq compared to conventional diesel vehicles over more neutral-grade highway routes, but emitted up to 12% greater CO2-eq emissions over routes with higher engine loads.

  9. Fission gas release and fuel rod chemistry related to extended burnup

    International Nuclear Information System (INIS)

    1993-04-01

    The purpose of the meeting was to review the state of the art in fission gas release and fuel rod chemistry related to extended burnup. The meeting was held in a time when national and international programmes on water reactor fuel irradiated in experimental reactors were still ongoing or had reached their conclusion, and when lead test assemblies had reached high burnup in power reactors and been examined. At the same time, several out-of-pile experiments on high burnup fuel or with simulated fuel were being carried out. As a result, significant progress has been registered since the last meeting, particularly in the evaluation of fuel temperature, the degradation of the global thermal conductivity with burnup and in the understanding of the impact on fission gas release. Fifty five participants from 16 countries and one international organization attended the meeting. 28 papers were presented. A separate abstract was prepared for each of the papers. Refs, figs, tabs and photos

  10. IFPE/IFA-432, Fission Gas Release, Mechanical Interaction BWR Fuel Rods, Halden

    International Nuclear Information System (INIS)

    Turnbull, J.A.

    1996-01-01

    Description: It contains data from experiments that have been performed at the IFE/OECD Halden Reactor Project, available for use in fuel performance studies. It covers experiments on thermal performance, fission product release, clad properties and pellet clad mechanical interaction. It includes also experimental data relevant to high burn-up behaviour. IFA-432: Measurements of fuel temperature response, fission gas release and mechanical interaction on BWR-type fuel rods up to high burn-ups. The assembly featured several variations in rod design parameters, including fuel type, fuel/cladding gap size, fill gas composition (He and Xe) and fuel stability. It contained 6 BWR-type fuel rods with fuel centre thermocouples at two horizontal planes, rods were also equipped with pressure transducers and cladding extensometers. Only data from 6 rods are compiled here

  11. Recent improvements in modelling fission gas release and rod deformation on metallic fuel in LMR

    International Nuclear Information System (INIS)

    Hwang, Woan; Lee, Byoung-Oon; Kim, Young Jin

    2000-01-01

    Metallic fuel design is a key feature to assure LMR core safety goals. To date, a large effort has been devoted to the development of the MACSIS code for metallic fuel rod design and the evaluation of operational limits under irradiation conditions. The updated models of fission gas release, fuel core swelling, and rod deformation are incorporated into the correspondence routines in MACSIS MOD1. The MACSIS MOD1 which is a new version of MACSIS, has been partly benchmarked on FGR, fuel swelling and rod deformation comparing with the results of U-Zr and U-Pu-Zr metal fuels irradiated in LMRs. The MACSIS MOD1 predicts, relatively well, the absolute magnitudes and trends of the gas release and rod deformations depending on burn-up, and it gives better agreement with the experimental data than the previous predictions of MACSIS and the results of the empirical model

  12. Unit mechanisms of fission gas release: Current understanding and future needs

    Science.gov (United States)

    Tonks, Michael; Andersson, David; Devanathan, Ram; Dubourg, Roland; El-Azab, Anter; Freyss, Michel; Iglesias, Fernando; Kulacsy, Katalin; Pastore, Giovanni; Phillpot, Simon R.; Welland, Michael

    2018-06-01

    Gaseous fission product transport and release has a large impact on fuel performance, degrading fuel and gap properties. While gaseous fission product behavior has been investigated with bulk reactor experiments and simplified analytical models, recent improvements in experimental and modeling approaches at the atomistic and mesoscales are beginning to reveal new understanding of the unit mechanisms that define fission product behavior. Here, existing research on the basic mechanisms of fission gas release during normal reactor operation are summarized and critical areas where work is needed are identified. This basic understanding of the fission gas behavior mechanisms has the potential to revolutionize our ability to predict fission product behavior and to design fuels with improved performance. In addition, this work can serve as a model on how a coupled experimental and modeling approach can be applied to understand the unit mechanisms behind other critical behaviors in reactor materials.

  13. Tritium release from advanced beryllium materials after loading by tritium/hydrogen gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, Vladimir, E-mail: vladimir.chakin@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rolli, Rolf; Moeslang, Anton; Kurinskiy, Petr; Vladimirov, Pavel [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Dorn, Christopher [Materion Beryllium & Composites, 6070 Parkland Boulevard, Mayfield Heights, OH 44124-4191 (United States); Kupriyanov, Igor [Bochvar Russian Scientific Research Institute of Inorganic Materials, Rogova str., 5, 123098 Moscow (Russian Federation)

    2016-06-15

    Highlights: • A major tritium release peak for beryllium samples occurs at temperatures higher than 1250 K. • A beryllium grade with comparatively smaller grain size has a comparatively higher tritium release compared to the grade with larger grain size. • The pebbles of irregular shape with the grain size of 10–30 μm produced by the crushing method demonstrate the highest tritium release rate. - Abstract: Comparison of different beryllium samples on tritium release and retention properties after high-temperature loading by tritium/hydrogen gas mixture and following temperature-programmed desorption (TPD) tests has been performed. The I-220-H grade produced by hot isostatic pressing (HIP) having the smallest grain size, the pebbles of irregular shape with the smallest grain size (10–30 μm) produced by the crushing method (CM), and the pebbles with 1 mm diameter produced by the fluoride reduction method (FRM) having a highly developed inherent porosity show the highest release rate. Grain size and porosity are considered as key structural parameters for comparison and ranking of different beryllium materials on tritium release and retention properties.

  14. Natural Gas as a Future Fuel for Heavy-Duty Vehicles

    International Nuclear Information System (INIS)

    Wai-Lin Litzke; James Wegrzyn

    2001-01-01

    In addition to their significant environmental impacts, medium-duty and heavy-duty (HD) vehicles are high volume fuel users. Development of such vehicles, which include transit buses, refuse trucks, and HD Class 6-8 trucks, that are fueled with natural gas is strategic to market introduction of natural gas vehicles (NGV). Over the past five years the Department of Energy's (DOE) Office of Heavy Vehicle Technologies (OHVT) has funded technological developments in NGV systems to support the growth of this sector in the highly competitive transportation market. The goals are to minimize emissions associated with NGV use, to improve on the economies of scale, and to continue supporting the testing and safety assessments of all new systems. This paper provides an overview of the status of major projects under a program supported by DOE/OHVT and managed by Brookhaven National Laboratory. The discussion focuses on the program's technical strategy in meeting specific goals proposed by the N GV industry and the government. Relevant projects include the development of low-cost fuel storage, fueling infrastructure, and HD vehicle applications

  15. Life-cycle greenhouse gas analysis of LNG as a heavy vehicle fuel in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Arteconi, A.; Brandoni, C.; Evangelista, D.; Polonara, F. [Universita Politecnica delle Marche, Dipartimento di Energetica, Via Brecce Bianche, 1-60131 Ancona (Italy)

    2010-06-15

    The aim of the present study was to compare the life cycle, in terms of greenhouse gas (GHG) emissions, of diesel and liquefied natural gas (LNG) used as fuels for heavy-duty vehicles in the European market (EU-15). A literature review revealed that the numerous studies conducted have reported different results when the authors departed from different baseline assumptions and reference scenarios. For our study, we concentrated on the European scenario and on heavy-duty road transport vehicles, given their important incidence on the global emissions of GHG. Two possible LNG procurement strategies were considered i.e. purchasing it directly from the regasification terminal (LNG-TER) or producing LNG locally (at the service station) with small-scale plants (LNG-SSL). We ascertained that the use of LNG-TER enables a 10% reduction in GHG emissions by comparison with diesel, while the emissions resulting from the LNG-SSL solution are comparable with those of diesel. (author)

  16. Liquid-gas phase transition and isospin fractionation in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Xing Yongzhong; Liu Jianye; Guo Wenjun

    2004-01-01

    The liquid-gas phase transition in the heavy ion collisions and nuclear matter has been an important topic and got achievements, such as, based on the studies by H.Q. Song et al the critical temperature of liquid-gas phase transition enhances with increasing the mass of system and reduces as the increase of the neutron proton ratio of system. As authors know that both the liquid-gas phase transition and the isospin fractionation occur in the spinodal instability region at the nuclear density below the normal nuclear density. In particular, these two dynamical processes lead to the separation of nuclear matter into the liquid phase and gas phase. In this case to compare their dynamical behaviors is interested. The authors investigate the dependence of isospin fractionation degree on the mass and neutron proton ratio of system by using the isospin dependent quantum molecular dynamics model. The authors found that the degree of isospin fractionation (N/Z) n /(N/Z) imf decreases with increasing the mass of the system. This is just similar to the enhance of the critical temperature of liquid-gas phase transition T c as the increase of system mass. Because the enhance of T c is not favorable for the liquid-gas transition taking place, which reduces the isospin fractionation process and leads to decrease of (N/Z) n /(N/Z) imf . However the degree of isospin fractionation enhances with increasing the neutron proton ratio of the system. It is just corresponding to the reduce of T c of the liquid-gas phase transition as the increase of the isospin fractionation of the system. Because the reduce of T c enhances the liquid-gas phase transition process and also prompts the isospin fractionation process leading the increase of the isospin fractionation degree. To sum up, there are very similar dynamical behaviors for the degree of isospin fractionation and the critical temperature of the liquid-gas phase transition. So dynamical properties of the liquid-gas phase transition can

  17. Heavy haze in winter Beijing driven by fast gas phase oxidation

    Science.gov (United States)

    Lu, K.; Tan, Z.; Wang, H.; Li, X.; Wu, Z.; Chen, Q.; Wu, Y.; Ma, X.; Liu, Y.; Chen, X.; Shang, D.; Dong, H.; Zeng, L.; Shao, M.; Hu, M.; Fuchs, H.; Novelli, A.; Broch, S.; Hofzumahaus, A.; Holland, F.; Rohrer, F.; Bohn, B.; Georgios, G.; Schmitt, S. H.; Schlag, P.; Kiendler-Scharr, A.; Wahner, A.; Zhang, Y.

    2017-12-01

    Heavy haze conditions were frequently presented in the airsheds of Beijing and surrounding areas, especially during winter time. To explore the trace gas oxidation and the subsequent formation of aerosols, a comprehensive field campaign was performed at a regional site (in the campus of University of Chinese Academy of Science, UCAS) in Beijing winter 2016. Serious haze pollution processes were often observed with the fast increase of inorganic salt (especially nitrate) and these pollutions were always associated with enhanced humidity and the concentrations of PAN (PeroxyAcyl Nitrates) which is normally a marker of gas phase oxidations from NOx and VOCs. Moreover, based on the measurements of OH, HO2, RO2, total OH reactivity, N2O5, NO, NO2, SO2, particle concentrations/distributions/chemical compositions, and meteorological parameters, the gas phase oxidation rates that leads to the formation of sulfate, nitrate and secondary organic aerosols were estimated. These determined formation rates were clearly enhanced by several folds during pollution episodes compared to that of the clean air masses. Preliminary analysis result showed that the gas phase formation potential of nitrate and secondary organic aerosols were larger than the observed concentrations of nitrate and SOA of which the excess production may be explained by deposition and dilution.

  18. Influence of carbonation under oxy-fuel combustion flue gas on the leachability of heavy metals in MSWI fly ash.

    Science.gov (United States)

    Ni, Peng; Xiong, Zhuo; Tian, Chong; Li, Hailong; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2017-09-01

    Due to the high cost of pure CO 2 , carbonation of MSWI fly ash has not been fully developed. It is essential to select a kind of reaction gas with rich CO 2 instead of pure CO 2 . The CO 2 uptake and leaching toxicity of heavy metals in three typical types of municipal solid waste incinerator (MSWI) fly ash were investigated with simulated oxy-fuel combustion flue gas under different reaction temperatures, which was compared with both pure CO 2 and simulated air combustion flue gas. The CO 2 uptake under simulated oxy-fuel combustion flue gas were similar to that of pure CO 2 . The leaching concentration of heavy metals in all MSWI fly ash samples, especially in ash from Changzhou, China (CZ), decreased after carbonation. Specifically, the leached Pb concentration of the CZ MSWI fly ash decreased 92% under oxy-fuel combustion flue gas, 95% under pure CO 2 atmosphere and 84% under the air combustion flue gas. After carbonation, the leaching concentration of Pb was below the Chinese legal limit. The leaching concentration of Zn from CZ sample decreased 69% under oxy-fuel combustion flue gas, which of Cu, As, Cr and Hg decreased 25%, 33%, 11% and 21%, respectively. In the other two samples of Xuzhou, China (XZ) and Wuhan, China (WH), the leaching characteristics of heavy metals were similar to the CZ sample. The speciation of heavy metals was largely changed from the exchangeable to carbonated fraction because of the carbonation reaction under simulated oxy-fuel combustion flue gas. After carbonation reaction, most of heavy metals bound in carbonates became more stable and leached less. Therefore, oxy-fuel combustion flue gas could be a low-cost source for carbonation of MSWI fly ash. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Unit mechanisms of fission gas release: Current understanding and future needs

    Energy Technology Data Exchange (ETDEWEB)

    Tonks, Michael; Andersson, David; Devanathan, Ram; Dubourg, Roland; El-Azab, Anter; Freyss, Michel; Iglesias, Fernando; Kulacsy, Katalin; Pastore, Giovanni; Phillpot, Simon R.; Welland, Michael

    2018-06-01

    Gaseous fission product transport and release has a large impact on fuel performance, degrading fuel properties and, once the gas is released into the gap between the fuel and cladding, lowering gap thermal conductivity and increasing gap pressure. While gaseous fission product behavior has been investigated with bulk reactor experiments and simplified analytical models, recent improvements in experimental and modeling approaches at the atomistic and mesoscales are being applied to provide unprecedented understanding of the unit mechanisms that define the fission product behavior. In this article, existing research on the basic mechanisms behind the various stages of fission gas release during normal reactor operation are summarized and critical areas where experimental and simulation work is needed are identified. This basic understanding of the fission gas behavior mechanisms has the potential to revolutionize our ability to predict fission product behavior during reactor operation and to design fuels that have improved fission product retention. In addition, this work can serve as a model on how a coupled experimental and modeling approach can be applied to understand the unit mechanisms behind other critical behaviors in reactor materials.

  20. Contribution to the study of the fission-gas release in metallic nuclear fuels

    International Nuclear Information System (INIS)

    Kryger, B.

    1969-10-01

    In order to study the effect of an external pressure on the limitation of swelling due to fission-gas precipitation, some irradiations have been carried out at burn-ups of about 35.000 MWd/ton, and at average sample temperatures of 575 Celsius degrees, of non-alloyed uranium and uranium 8 per cent molybdenum gained in a thick stainless steel can. A cylindrical central hole allows a fuel swelling from 20 to 33 per cent according to the experiment. After irradiation, the uranium samples showed two types of can rupture: one is due to the fuel swelling, and the other, to the pressure of the fission gases, released through a network of microcracks. The cans of the uranium-molybdenum samples are all undamaged and it is shown that the gas release occurs by interconnection of the bubbles for swelling values higher than those obtained in the case of uranium. For each type of fuel, a swelling-fission gas release relationship is established. The results suggest that good performances with a metallic fuel intended for use in fast reactor conditions can be obtained. (author) [fr

  1. A method of surface area measurement of fuel materials by fission gas release at low temperature

    International Nuclear Information System (INIS)

    Kaimal, K.N.G.; Naik, M.C.; Paul, A.R.; Venkateswarlu, K.S.

    1989-01-01

    The present report deals with the development of a method for surface area measurement of nuclear fuel as well as fissile doped materials by fission gas release study at low temperature. The method is based on the evaluation of knock-out release rate of fission 133 Xe from irradiated fuel after sufficient cooling to decay the short lived activity. The report also describes the fabrication of an ampoule breaker unit for such study. Knock-out release rate of 133 Xe has been studied from UO 2 powders having varying surface area 'S' ranging from 270 cm 2 /gm to 4100 cm 2 /gm at two fissioning rates 10 12 f/cm 3 . sec. and 3.2x10 10 f/cm.sec. A relation between K and A has been established and discussed in this report. (author). 6 refs

  2. Models for recurrent gas release event behavior in hazardous waste tanks

    International Nuclear Information System (INIS)

    Anderson, D.N.; Arnold, B.C.

    1994-08-01

    Certain radioactive waste storage tanks at the United States Department of Energy Hanford facilities continuously generate gases as a result of radiolysis and chemical reactions. The congealed sludge in these tanks traps the gases and causes the level of the waste within the tanks to rise. The waste level continues to rise until the sludge becomes buoyant and ''rolls over'', changing places with heavier fluid on top. During a rollover, the trapped gases are released, resulting, in a sudden drop in the waste level. This is known as a gas release event (GRE). After a GRE, the wastes leading to another GRE. We present nonlinear time waste re-congeals and gas again accumulates leading to another GRE. We present nonlinear time series models that produce simulated sample paths that closely resemble the temporal history of waste levels in these tanks. The models also imitate the random GRE, behavior observed in the temporal waste level history of a storage tank. We are interested in using the structure of these models to understand the probabilistic behavior of the random variable ''time between consecutive GRE's''. Understanding the stochastic nature of this random variable is important because the hydrogen and nitrous oxide gases released from a GRE, are flammable and the ammonia that is released is a health risk. From a safety perspective, activity around such waste tanks should be halted when a GRE is imminent. With credible GRE models, we can establish time windows in which waste tank research and maintenance activities can be safely performed

  3. Modelling of oceanic gas hydrate instability and methane release in response to climate change

    International Nuclear Information System (INIS)

    Reagan, M.T.; Moridis, G.J.

    2008-01-01

    Methane releases from oceanic hydrates are thought to have played a significant role in climatic changes that have occurred in the past. In this study, gas hydrate accumulations subjected to temperature changes were modelled in order to assess their potential for future methane releases into the ocean. Recent ocean and atmospheric chemistry studies were used to model 2 climate scenarios. Two types of hydrate accumulations were used to represent dispersed, low-saturation deposits. The 1-D multiphase thermodynamic-hydrological model considered the properties of benthic sediments; ocean depth; sea floor temperature; the saturation and distribution of the hydrates; and the effect of benthic biogeochemical activity. Results of the simulations showed that shallow deposits undergo rapid dissociation and are capable of producing methane fluxes of 2 to 13 mol m 3 per year over a period of decades. The fluxes exceed the ability of the anaerobic sea floor environment to sequester or consume the methane. A large proportion of the methane released in the scenarios emerged in the gas phase. Arctic hydrates may pose a threat to regional and global ecological systems. It was concluded that results of the study will be coupled with global climate models in order to assess the impact of the methane releases in relation to global climatic change. 39 refs., 5 figs

  4. Estimation of large early release frequency for Advanced Heavy Water Reactor

    International Nuclear Information System (INIS)

    Santhosh, T.V.; Thangamani, I.; Shrivastava, A.; Vinod, Gopika; Verma, Vishnu; Vijayan, P.K.

    2015-01-01

    Level 2 probabilistic safety assessment (PSA) examines severe accidents through a combination of probabilistic and deterministic approaches, in order to determine the release of radionuclides from containment, including the physical processes that are involved in the loss of structural integrity of the reactor core. The probabilistic part focuses on the reliability evaluation of containment systems and the deterministic part focuses on the analysis of the physical processes of an accident (timing and magnitude of radioactivity release), and the response of the containment. The important tasks involved are: (i) grouping and categorization of accident sequences into plant damage states (PDSs) (ii) development of a containment event trees (CETs) (iii) development of CET top event definitions and quantification of failure probabilities, and (iv) assigning the release categories and estimation of large early release frequency (LERF). LERF is defined as the frequency of those accidents leading to rapid, unmitigated release of airborne fission products from the containment to the environment occurring before the effective implementation of offsite emergency response and protective actions such that there is the potential for early health effects. Such accidents generally include unscrubbed releases associated with early containment failure shortly after vessel breach, containment bypass events, and loss of containment isolation. Preliminary assessment of LERF, based on release categorization from qualitative expert judgement, has been carried out and the estimated LERF is found to be 1e-13/yr. The dominant contributors are: (a) LB LOCA with the failure of prompt shutdown coupled with containment isolation failure, (b) containment bypass event from main steam line break outside containment coupled with failure of main steam isolation valves, and (c) LB LOCA with complete failure of emergency core cooling system (ECCS) and loss of moderator cooling

  5. Modelling of fission gas release in rods from the International DEMO-RAMP-II Project at Studsvik

    International Nuclear Information System (INIS)

    Malen, K.

    1983-01-01

    The DEMO-RAMP-II rods had a burn-up of 25-30 MWd/kg U. They were ramped to powers in the range 40-50 kW/m with hold times between 10 s and 4.5 minutes. In spite of the short hold times the fission gas release at the higher powers was more than 1%. With these short hold times it is natural to assume that mixing of released gas with plenum gas is limited. Modelling has been performed using GAPCONSV (a modified GAPCON-THERMAL-2) both with and without mixing of released gas with plenum gas. In particular for the high power-short duration ramps only the ''no mixing'' modelling yields release fractions comparable to the experimental values. (author)

  6. Estimating particle release through gas leaks in dry powder shipping containers

    International Nuclear Information System (INIS)

    Schwendiman, L.C.

    1977-06-01

    Information is presented from which an estimate can be made of the release of plutonium oxide from shipping containers. The leak diameter is estimated from gas leak tests of the container and an estimate is made of gas leak rate as a function of pressure over the time of interest in the accident. These calculations are limited in accuracy because of assumptions regarding leak geometry and the basic formulations of hydrodynamic flow for the assumed conditions. Sonic flow is assumed to be the limiting gas flow rate. Particles leaking from the air space above the powder will be limited by the low availability of particles due to rapid settling, the very limited driving force (pressure buildup) during the first minute, and the deposition in the leak channel. Equations are given to estimate deposition losses. Leaks of particles occurring below the level of the bulk powder will be limited by mechanical interference when leaks are of dimension smaller than particle sizes present. Some limiting cases can be calculated. When the leak dimension is large compared to the particle sizes present, maximum particle releases can be estimated, but will be very conservative. Further theoretical and experimental studies are needed to better define the hydrodynamics of gas flow in leaks of the size being considered, and to establish particle transport rates through known geometry leak paths

  7. Simulation of pellet-cladding thermomechanical interaction and fission gas release

    International Nuclear Information System (INIS)

    Denis, Alicia; Soba, Alejandro

    2003-01-01

    This paper summarizes the present status of a computer code that describes some of the main phenomena occurring in a nuclear fuel rod throughout its life. Temperature distribution, thermal expansion, elastic and plastic strains, creep, mechanical interaction between pellet and cladding, fission gas release, gas mixing, swelling, and densification are modeled. The modular structure of the code allows for the incorporation of models to simulate different phenomena and material properties. Collapsible rods can be also simulated. The code is bidimensional, assumes cylindrical symmetry for the rod and uses the finite element method to integrate the differential equations. The stress-strain and heat conduction problems are nonlinear due to plasticity and to the temperature dependence of the thermal conductivity. The fission gas inventory is calculated with a diffusion model, assuming spherical grains and using a one-dimensional finite element scheme. Pressure increase, swelling and densification are coupled with the stress field. Good results are obtained for the simulation of the irradiation tests of the first argentine prototypes of MOX fuels, where the bamboo effect is clearly observed, and of the FUMEX series for the fuel centerline temperature, the inside rod pressure and the fractional gas release.

  8. Diluted Operation of a Heavy-Duty Natural Gas Engine - Aiming at Improved Effciency, Emission and Maximum Load

    OpenAIRE

    Kaiadi, Mehrzad

    2011-01-01

    Most heavy-duty engines are diesel operated. Severe emission regulations, high fuel prices, high technology costs (e.g. catalysts, fuel injection systems) and unsustainably in supplying fuel are enough reasons to convenience engine developers to explore alternative technologies or fuels. Using natural gas/biogas can be a very good alternative due to the attractive fuel properties regarding emission reduction and engine operation. Heavy-duty diesel engines can be easily converted for natur...

  9. The release code package REVOLS/RENONS for fission product release from a liquid sodium pool into an inert gas atmosphere

    International Nuclear Information System (INIS)

    Starflinger, J.; Scholtyssek, W.; Unger, H.

    1994-12-01

    For aerosol source term considerations in the field of nuclear safety, the investigation of the release of volatile and non-volatile species from liquid surfaces into a gas atmosphere is important. In case of a hypothetical liquid metal fast breeder reactor accident with tank failure, primary coolant sodium with suspended or solved fuel particles and fission products may be released into the containment. The computer code package REVOLS/RENONS, based on a theoretical mechanistic model with a modular structure, has been developed for the prediction of sodium release as well as volatile and non-volatile radionuclide release from a liquid pool surface into the inert gas atmosphere of the inner containment. Hereby the release of sodium and volatile fission products, like cesium and sodium iodide, is calculated using a theoretical model in a mass transfer coefficient formulation. This model has been transposed into the code version REVOLS.MOD1.1, which is discussed here. It enables parameter analysis under highly variable user-defined boundary conditions. Whereas the evaporative release of the volatile components is governed by diffusive and convective transport processes, the release of the non-volatile ones may be governed by mechanical processes which lead to droplet entrainment from the wavy pool surface under conditions of natural or forced convection into the atmosphere. The mechanistic model calculates the liquid entrainment rate of the non-volatile species, like the fission product strontium oxide and the fuel (uranium dioxide) from a liquid pool surface into a parallel gas flow. The mechanistic model has been transposed into the computer code package REVOLS/RENONS, which is discussed here. Hereby the module REVOLS (RElease of VOLatile Species) calculates the evaporative release of the volatile species, while the module RENONS (RElease of NON-Volatile Species) computes the entrainment release of the non-volatile radionuclides. (orig./HP) [de

  10. Aqueous studies of hydrogen sulfide releases from a heavy water extraction facility

    International Nuclear Information System (INIS)

    Kiser, D.L.

    1979-03-01

    Upsets in the operation of the wastewater strippers in the 400 Area of the Savannah River Plant have released hydrogen sulfide in quantities as large as 1800 kg to the effluent stream. Fish kills in the swamp area of Beaver Dam Creek have occurred following the large releases. A literature survey revealed volatilization and oxidation as the major loss mechanisms of H 2 S. Laboratory investigations supported the literature survey. The computer code for pollutant transport in a stream, LODIPS, has an option to account for sink-source effects in a stream. Volatilization and oxidation rate constants were developed for the sink option from two H 2 S releases (18 kg and 118 kg) and results were predicted with LODIPS. Based on the predicted concentration-time profiles for various hypothetical cases, releases as small as 568 kg if discharged over a 30-minute period or releases as large as 1818 kg if discharged over a 360-minute period or less are lethal to swamp fish

  11. On the rate determining step in fission gas release from high burn-up water reactor fuel during power transients

    International Nuclear Information System (INIS)

    Walker, C.T.; Mogensen, M.

    1987-01-01

    The radial distribution of grain boundary gas in a PWR and a BWR fuel is reported. The measurements were made using a new approach involving X-ray fluorescence analysis and electron probe microanalysis. In both fuels the concentration of grain boundary gas was much higher than hitherto suspected. The gas was mainly contained in the bubble/pore structure. The factors that determined the fraction of gas released from the grains and the level of gas retention on the grain boundaries are identified and discussed. The variables involved are the local fuel stoichiometry, the amount of open porosity, the magnitude of the local compressive hydrostatic stress and the interaction of metallic precipitates with gas bubbles on the grain faces. It is concluded that under transient conditions the interlinkage of gas bubbles on the grain faces and the subsequent formation of grain edge tunnels is the rate determining step for gas release; at least when high burn-up fuel is involved. (orig.)

  12. Analysis of fission gas release-to-birth ratio data from the AGR irradiations

    International Nuclear Information System (INIS)

    Einerson, Jeffrey J.; Pham, Binh T.; Scates, Dawn M.; Maki, John T.; Petti, David A.

    2016-01-01

    A series of advanced gas reactor (AGR) irradiation tests is being conducted in the advanced test reactor (ATR) at Idaho National Laboratory (INL) in support of development and qualification of tristructural isotropic (TRISO) fuel used in the High temperature gas-cooled reactor (HTGR). Each AGR test consists of multiple independent capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples (TC) embedded in the graphite enabling temperature control. For AGR-1, the first US irradiation of modern TRISO fuel completed in 2009, there were no particle failures detected. For AGR-2, a few exposed kernels existed in the fuel compacts based upon quality control data. For the AGR-3/4 experiment, particle failures in all capsules were expected because of the use of designed-to-fail (DTF) fuel particles whose kernels are identical to the driver fuel kernels and whose coatings are designed to fail under irradiation. The release-rate-to-birth-rate ratio (R/B) for each of krypton and xenon isotopes is calculated from release rates measured by the germanium detectors used in the AGR fission product monitoring (FPM) system installed downstream from each irradiated capsule. Birth rates are calculated based on the fission power in the experiment and fission product generation models. Thus, this R/B is a measure of the ability of fuel particle coating layers and compact matrix to retain fission gas atoms preventing their release into the sweep gas flow. The major factors that govern gaseous diffusion and release processes are found to be fuel material diffusion coefficient, temperature, and isotopic decay constant. To compare the release behavior among the AGR capsules and historic experiments, the R/B per failed particle is used. HTGR designers use this parameter in their fission product behavior models. For the U.S. TRISO fuel, a regression analysis is performed to establish functional relationships

  13. Analysis of Fission Gas Release-to-Birth Ratio Data from the AGR Irradiations

    International Nuclear Information System (INIS)

    Einerson, Jeffrey J.; Pham, Binh T.; Scates, Dawn M.; Maki, John T.; Petti, David A.

    2014-01-01

    A series of Advanced Gas Reactor (AGR) irradiation tests is being conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) in support of development and qualification of tristructural isotropic (TRISO) fuel used in the High Temperature Gas-cooled Reactor (HTGR). Each AGR test consists of multiple independent capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples (TC) embedded in the graphite enabling temperature control. For AGR-1, the first US irradiation of modern TRISO fuel completed in 2009, there were no particle failures detected. For AGR-2, a few exposed kernels existed in the fuel compacts based upon quality control data. For the AGR-3/4 experiment, particle failures in all capsules were expected because of the use of designed-to-fail (DTF) fuel particles whose kernels are identical to the driver fuel kernels and whose coatings are designed to fail under irradiation. The release-rate-to-birth-rate ratio (R/B) for each of krypton and xenon isotopes is calculated from release rates measured by the germanium detectors used in the AGR Fission Product Monitoring (FPM) System installed downstream from each irradiated capsule. Birth rates are calculated based on the fission power in the experiment and fission product generation models. Thus, this R/B is a measure of the ability of fuel particle coating layers and compact matrix to retain fission gas atoms preventing their release into the sweep gas flow. The major factors that govern gaseous diffusion and release processes are found to be fuel material diffusion coefficient, temperature, and isotopic decay constant. To compare the release behavior among the AGR capsules and historic experiments, the R/B per failed particle is used. HTGR designers use this parameter in their fission product behavior models. For the U.S. TRISO fuel, a regression analysis is performed to establish functional relationships

  14. Analysis of fission gas release-to-birth ratio data from the AGR irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Einerson, Jeffrey J., E-mail: jeffrey.einerson@inl.gov; Pham, Binh T.; Scates, Dawn M.; Maki, John T.; Petti, David A.

    2016-09-15

    A series of advanced gas reactor (AGR) irradiation tests is being conducted in the advanced test reactor (ATR) at Idaho National Laboratory (INL) in support of development and qualification of tristructural isotropic (TRISO) fuel used in the High temperature gas-cooled reactor (HTGR). Each AGR test consists of multiple independent capsules containing fuel compacts placed in a graphite cylinder shrouded by a steel shell. These capsules are instrumented with thermocouples (TC) embedded in the graphite enabling temperature control. For AGR-1, the first US irradiation of modern TRISO fuel completed in 2009, there were no particle failures detected. For AGR-2, a few exposed kernels existed in the fuel compacts based upon quality control data. For the AGR-3/4 experiment, particle failures in all capsules were expected because of the use of designed-to-fail (DTF) fuel particles whose kernels are identical to the driver fuel kernels and whose coatings are designed to fail under irradiation. The release-rate-to-birth-rate ratio (R/B) for each of krypton and xenon isotopes is calculated from release rates measured by the germanium detectors used in the AGR fission product monitoring (FPM) system installed downstream from each irradiated capsule. Birth rates are calculated based on the fission power in the experiment and fission product generation models. Thus, this R/B is a measure of the ability of fuel particle coating layers and compact matrix to retain fission gas atoms preventing their release into the sweep gas flow. The major factors that govern gaseous diffusion and release processes are found to be fuel material diffusion coefficient, temperature, and isotopic decay constant. To compare the release behavior among the AGR capsules and historic experiments, the R/B per failed particle is used. HTGR designers use this parameter in their fission product behavior models. For the U.S. TRISO fuel, a regression analysis is performed to establish functional relationships

  15. Experiments to investigate the effects of small changes in fuel stoichiometry on fission gas release

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, P S; Smith, R C [Windscale Lab., AEA Technology, Seascale, Cumbria (United Kingdom)

    1997-08-01

    Fuel pin failure in-reactor leads to fission product and in the case of a PWR fuel debris release to the coolant. For economic reasons immediate shutdown and discharge of failed fuel needs to be avoided but this needs to be counter-balanced against the increasing dose to operators. PWR practice is to continue running wit failed rods, monitoring coolant activity, and only shutting down the reactor and discharging the fuel when circuit activity levels become unacceptable. The rate of fission product release under failed fuel conditions is of key importance and considerable effort has been directed towards establishing the dependency of release on temperature, heating rate, burn-up, and also the extent of fuel oxidation. As a precursor to a possible wider investigation of this area, a small programme was mounted during 1992/1993 to confirm whether small changes in the oxidation state of the fuel, for example those caused by minor cladding defects, would significantly effect fuel behaviour during postulated design basis faults. The objective of the programme was to determine the effects of small departures from stoichiometric fuel composition on fission gas release, and to compare the results with the current methodology for calculating releases under fault conditions. A total of eight experiments was performed. Two were intended as baseline tests to provide a reference with which to compare the effect of oxidation state influenced behaviour with that of thermal effects. It was found that small changes in stoichiometry of {sup {approx}}1 x 10{sup -6} had little or no effect on release but that changes of {sup {approx}} 1 x 10{sup -4} were observed to increase the diffusion coefficient, for {sup 85}Kr, by up to an order of magnitude and hence greatly increase the release rate. The stoichiometry of the sample used in these tests was, for convenience, adjusted using He/H{sub 2}/H{sub 2}O atmospheres. (Abstract Truncated)

  16. Analysis of a gas turbine driven hybrid drive system for heavy vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Malmquist, Anders

    1999-07-01

    The goal of this thesis has been to analyze the performance and behavior of a gas turbine driven hybrid drive train. The thesis covers both computer simulations and experimental tests. In two case studies, a number of measurements have been made on gas turbine driven hybrid vehicles that are developed by Volvo and ABB. In the recent years, much effort is currently put into the design and analysis of hybrid drive trains. Many studies involve computer simulations, but they are often made on a general level. This thesis concentrate on gas turbine driven hybrids for heavy vehicles, a field that has previously not been covered to a large extent in academic studies. A major contribution to the field of hybrid drive train design is the development of detailed simulation models that have a close connection to hybrids that are actually built and tested. The access to detailed gas turbine data has further enhanced the possibility to design a dynamic model of the gas turbine driven and the electric circuits. The combination of simulations and extensive field experience gains new knowledge on the properties of gas turbines in hybrid drive trains. Two simulation models have been developed in Matlab and Simulink. One is a quasi-steady state model that can be used for drive cycle simulations, e.g. a complete bus line. The other is a transient model that combines the thermodynamic properties of the gas turbine, the mechanical properties of the combined turbine-generator shaft, the electric power circuit and the control system. The transient model has been used to simulate the power response during accelerations and retardation. An analysis of the internal energy flows and the system efficiency of a hybrid drive train contributes to the understanding of the properties of series hybrid drive trains. An important part of the topology is that the system is based on a DC/DC-converter that is connected between the battery and the DC-bus. It controls the DC-bus voltage and by this

  17. Influence of methane emissions and vehicle efficiency on the climate implications of heavy-duty natural gas trucks.

    Science.gov (United States)

    Camuzeaux, Jonathan R; Alvarez, Ramón A; Brooks, Susanne A; Browne, Joshua B; Sterner, Thomas

    2015-06-02

    While natural gas produces lower carbon dioxide emissions than diesel during combustion, if enough methane is emitted across the fuel cycle, then switching a heavy-duty truck fleet from diesel to natural gas can produce net climate damages (more radiative forcing) for decades. Using the Technology Warming Potential methodology, we assess the climate implications of a diesel to natural gas switch in heavy-duty trucks. We consider spark ignition (SI) and high-pressure direct injection (HPDI) natural gas engines and compressed and liquefied natural gas. Given uncertainty surrounding several key assumptions and the potential for technology to evolve, results are evaluated for a range of inputs for well-to-pump natural gas loss rates, vehicle efficiency, and pump-to-wheels (in-use) methane emissions. Using reference case assumptions reflecting currently available data, we find that converting heavy-duty truck fleets leads to damages to the climate for several decades: around 70-90 years for the SI cases, and 50 years for the more efficient HPDI. Our range of results indicates that these fuel switches have the potential to produce climate benefits on all time frames, but combinations of significant well-to-wheels methane emissions reductions and natural gas vehicle efficiency improvements would be required.

  18. Analysis of fission gas release in LWR fuel using the BISON code

    Energy Technology Data Exchange (ETDEWEB)

    G. Pastore; J.D. Hales; S.R. Novascone; D.M. Perez; B.W. Spencer; R.L. Williamson

    2013-09-01

    Recent advances in the development of the finite-element based, multidimensional fuel performance code BISON of Idaho National Laboratory are presented. Specifically, the development, implementation and testing of a new model for the analysis of fission gas behavior in LWR-UO2 fuel during irradiation are summarized. While retaining a physics-based description of the relevant mechanisms, the model is characterized by a level of complexity suitable for application to engineering-scale nuclear fuel analysis and consistent with the uncertainties pertaining to some parameters. The treatment includes the fundamental features of fission gas behavior, among which are gas diffusion and precipitation in fuel grains, growth and coalescence of gas bubbles at grain faces, grain growth and grain boundary sweeping effects, thermal, athermal, and transient gas release. The BISON code incorporating the new model is applied to the simulation of irradiation experiments from the OECD/NEA International Fuel Performance Experiments database, also included in the IAEA coordinated research projects FUMEX-II and FUMEX-III. The comparison of the results with the available experimental data at moderate burn-up is presented, pointing out an encouraging predictive accuracy, without any fitting applied to the model parameters.

  19. A magnetic nanoparticle stabilized gas containing emulsion for multimodal imaging and triggered drug release.

    Science.gov (United States)

    Guo, Wei; Li, Diancheng; Zhu, Jia-an; Wei, Xiaohui; Men, Weiwei; Yin, Dazhi; Fan, Mingxia; Xu, Yuhong

    2014-06-01

    To develop a multimodal imaging guided and triggered drug delivery system based on a novel emulsion formulation composed of iron oxide nanoparticles, nanoscopic bubbles, and oil containing drugs. Iron oxide paramagnetic nanoparticles were synthesized and modified with surface conjugation of polyethylenimide (PEI) or Bovine Serum Albumin (BSA). Both particles were used to disperse and stabilize oil in water emulsions containing coumarin-6 as the model drug. Sulfur hexafluoride was introduced into the oil phase to form nanoscopic bubbles inside the emulsions. The resulted gas containing emulsions were evaluated for their magnetic resonance (MR) and ultrasound (US) imaging properties. The drug release profile triggered by ultrasound was also examined. We have successfully prepared the highly integrated multi-component emulsion system using the surface modified iron oxide nanoparticles to stabilize the interfaces. The resulted structure had distinctive MR and US imaging properties. Upon application of ultrasound waves, the gas containing emulsion would burst and encapsulated drug could be released. The integrated emulsion formulation was multifunctional with paramagnetic, sono-responsive and drug-carrying characteristics, which may have potential applications for disease diagnosis and imaging guided drug release.

  20. LOFC fission product release and circulating activity calculations for gas-cooled reactors

    International Nuclear Information System (INIS)

    Apperson, C.E. Jr.; Carruthers, L.M.; Lee, C.E.

    1977-01-01

    The inventories of fission products in a gas-cooled reactor under accident and normal steady state conditions are time and temperature dependent. To obtain a reasonable estimate of these inventories it is necessary to consider fuel failure, a temperature dependent variable, and radioactive decay, a time dependent variable. Using arbitrary radioactive decay chains and published fuel failure models for the High Temperature Gas-Cooled Reactor (HTGR), methods have been developed to evaluate the release of fission products during the Loss of Forced Circulation (LOFC) accident and the circulating and plateout fission product inventories during steady state non-accident operation. The LARC-2 model presented here neglects the time delays in the release from the HTGR due to diffusion of fission products from particles in the fuel rod through the graphite matrix. It also neglects the adsorption and evaporation process of metallics at the fuel rod-graphite and graphite-coolant hole interfaces. Any time delay due to the finite time of transport of fission products by convection through the coolant to the outside of the prestressed concrete reactor vessel (PCRV) is also neglected. This model assumes that all fission products released from fuel particles are immediately deposited outside the PCRV with no time delay

  1. Effect of cracks in coating on gas release from a fuel microparticle

    International Nuclear Information System (INIS)

    Bondarenko, A.G.; Gudkov, A.N.; Tselishchev, Yu.V.

    1988-01-01

    Effect of cracks in protective coating on gas release from a fuel microparticle is investigated in a general form. A fuel microparticle comprizing a kern, a buffer layer and an external protective coating is considered. The pressure of radioactive inert gases in the microparticle buffer layer is evaluated within the 1000-1800 K temperature range on the base of diffusion-defect-trap transport theory. It is shown that the process of radionuclide adsorption interaction with the coating material leads to a more abrupt than by exponent, weakening of mass transfer coefficient. In this case for long-living isotopes the effect of adsorption processes manifests weaker than for short-living ones. Mass transfer coefficient for the crack system depends sufficiently on the total pressure of gas mixture under the coating while for a single cracks such dependence is not observed. A conclusion is drawn that the obtained ratios can be applied for evaluating the character of fuel microparticle protective coating destruction (single non-intersecting cracks or a crack system) using the data on various nuclide release. These ratios can be also applied for the choice of the coating thichness under which gaseous fission product release from the fuel microparticle in case of its protective coating failure does not exceed the acceptable limits

  2. Chemical identities of radioiodine released from U3O8 in oxygen and inert gas atmospheres

    International Nuclear Information System (INIS)

    Tachikawa, E.; Nakashima, M.

    1977-01-01

    Irradiated U 3 O 8 was heated from room temperature to 1100 0 C in a temperature-programmed oven (5 0 C/min) in a flow of carrier gas. The iodine released to an inert gas was deposited in the temperature range from 200 to 300 0 C with a peak at 250 0 C (speciesA). This species is neither in a form combined with other fission products nor in elemental form. It is possibly a chemical combination with uranium. It reacts with oxygen, yielding species B characterized by its deposition at a temperature close to room temperature. The activation energy of this oxidation reaction was determined to be 6.0 +-0.5 Kcal/mol. Comparing the deposition-profile with those obtained with carrier-free I 2 and HI indicated that species B was I 2 . As for the formation of organic iodides accompanying the release in an inert gas, it was concluded that these were produced in radical reactions. Thus, in a presence of oxygen, organic iodides were formed in competition with the reactions of organic radicals with oxygen. (author)

  3. Acoustic mapping of shallow water gas releases using shipborne multibeam systems

    Science.gov (United States)

    Urban, Peter; Köser, Kevin; Weiß, Tim; Greinert, Jens

    2015-04-01

    Water column imaging (WCI) shipborne multibeam systems are effective tools for investigating marine free gas (bubble) release. Like single- and splitbeam systems they are very sensitive towards gas bubbles in the water column, and have the advantage of the wide swath opening angle, 120° or more allowing a better mapping and possible 3D investigations of targets in the water column. On the downside, WCI data are degraded by specific noise from side-lobe effects and are usually not calibrated for target backscattering strength analysis. Most approaches so far concentrated on manual investigations of bubbles in the water column data. Such investigations allow the detection of bubble streams (flares) and make it possible to get an impression about the strength of detected flares/the gas release. Because of the subjective character of these investigations it is difficult to understand how well an area has been investigated by a flare mapping survey and subjective impressions about flare strength can easily be fooled by the many acoustic effects multibeam systems create. Here we present a semi-automated approach that uses the behavior of bubble streams in varying water currents to detect and map their exact source positions. The focus of the method is application of objective rules for flare detection, which makes it possible to extract information about the quality of the seepage mapping survey, perform automated noise reduction and create acoustic maps with quality discriminators indicating how well an area has been mapped.

  4. Axial Turbine Aerodynamic Design of Small Heavy-Duty Gas Turbines

    International Nuclear Information System (INIS)

    Kim, Joung Seok; Lee, Wu Sang; Ryu, Je Wook

    2013-01-01

    This study describes the aerodynamic design procedure for the axial turbines of a small heavy-duty gas turbine engine being developed by Docosan Heavy Industries. The design procedure mainly consists of three parts: namely, flow path design, airfoil design, and 3a performance calculation. To design the optimized flow path, through flow calculations as well as the loss estimation are widely used to evaluate the effect of geometric variables, for example, shape of meridional plane, mean radius, blades axial gap, and had angle. During the airfoil design procedure, the optimum number of blades is calculated by empirical correlations based on the in/outlet flow angles, and then 2a airfoil planar sections are designed carefully, followed by 2a B2 NS calculations. The designed planar sections are stacked along the span wise direction, leading to a 3a surfaced airfoil shape. To consider the 3a effect on turbine performance, 3a multistage Euler calculation, single row, and multistage NS calculations are performed

  5. Transformation of heavy gas oils derived from oil sands to petrochemical feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Du Plessis, D.; Laureshen, C. [Alberta Energy Research Inst., Edmonton, AB (Canada)

    2006-07-01

    Alberta's petrochemical industry is primarily based on ethane. However, ethane could potentially impede future growth of Alberta's petrochemical industry because of increasing cost and diminishing supplies. Alternately, the rapidly growing oil sands production could provide abundant new feedstocks. Different integration schemes and technologies were evaluated in this study. Research on converting bitumen-derived heavy gas oil into petrochemical feedstock has resulted in the development of two novel technologies and process integration schemes, notably the NOVA heavy oil laboratory catalyst (NHC) process and the aromatic ring cleavage (ARORINCLE) process. This paper described progress to date on these two projects. The paper presented the experimental results for each scheme. For the ARORINCLE process, results were discussed in terms of the effect of process parameters on the hydrogenation step; effect of process parameters on the ring cleavage step; and integrating the upgrading and petrochemical complex. Early laboratory stage results of these two technologies were found to be encouraging. The authors recommended that work should progress to larger scale demonstration of the NHC and ARORINCLE technologies., 13 refs., 2 tabs., 5 figs.

  6. Features of hydrotreating catalytic cracking feed and heavy slow coking gas oils

    Energy Technology Data Exchange (ETDEWEB)

    Yefremov, N.I.; Kushnarev, D.F.; Frolov, P.A.; Chagovets, A.N.; Kalabin, G.A.

    1993-12-31

    A possible means of more extensive processing of crude oil is the use, in catalytic cracking, of heavy coking gas oils (HCGOs), a feature of which is a higher content of polycyclic aromatic compounds and resins by comparison with straight-run vacuum distillates. The presence of these compounds in catalytic cracking feed causes a reduction in the product yield and increased coke formation. Therefore, one of the problems of hydrotreating feedstock of this kind is the hydrogenation of polycyclic arenes. Processes of extensive desulphurization and denitration occur in parallel, since the sulphur and nitrogen compounds of HCGO are chiefly condensed benzoderivatives of thiophene, pyridine and carbazole, and largely concentrated in heavy aromatic and resinous fractions. The composition of the saturated part of the cracking feed plays a large role in achieving the optimum yields of gaseous and gasoline fractions. Thus an increase in the proportion of cyclanes in the feed raises the gasoline yield. In this way, an investigation of the hydrocarbon conversions during the hydrotreatment of cracking feed is of great importance. The present paper sets out the results for studying the change in the group-structural characteristics of the hydrogenation products of a mixture containing 30% HCGOs according to data of {sup 1}H and {sup 13}C NMR spectroscopy. 7 refs., 7 figs., 1 tab.

  7. Surfacing behavior and gas release of the physostome sprat (Sprattus sprattus) in ice-free and ice-covered waters

    KAUST Repository

    Solberg, Ingrid; Kaartvedt, Stein

    2013-01-01

    Upward-facing echosounders that provided continuous, long-term measurements were applied to address the surfacing behavior and gas release of the physostome sprat (Sprattus sprattus) throughout an entire winter in a 150-m-deep Norwegian fjord

  8. High-Temperature Desulfurization of Heavy Fuel-Derived Reformate Gas Streams for SOFC Applications

    Science.gov (United States)

    Flytzani-Stephanopoulos, Maria; Surgenor, Angela D.

    2007-01-01

    Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.

  9. Combined cogeneration equipment containing gas turbine using low sulphur heavy stock as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, Goro; Ishiki, Katsuhiko

    1988-03-10

    This paper describes the combined cogeneration in Chemical and Plastics Co. Madras (India) which uses low sulphur heavy stock (LSHS) as a fuel. By the combined cogeneration of gas turbine and boiler steam turbine power generation, the exhaust from the steam turbine is supplied to the factory as a process steam. This equipment has a capacity of 4835 kW in overall generation power and 23.5 tons/hrs. in steam evaporation. The gas turbine system is equipped with an axial-flow, 11 step compressor, an axial flow, 4 step turbine, and a single-can back flow combustor fixed to the intermediate casing. The temperature of the exhaust from the gas turbine is 542/sup 0/C. Low quality LSHS when burned exerts no influence on the service life of the turbine blades. The boiler is a horizontal bent pipe, forced circulation type, and the steam turbine is a back pressure control type. The fuel is treated with a horizontal, two drum, electrostatic separator to which a demulsifier is supplied, to be separated into oil and water. As to the vanadium salts contained in the fuels, a chemical liquid containing MgO as a major ingredient is added to the fuel prior to the combustion. Thereby, the melting temperature of the vanadium oxide is enhanced, which serves for prevention of the melting and adhesion of the vanadium oxide to the gas turbine. LSHS is a residual oil produced by the ordinary pressure distillation of India-produced crude oil, has a sulphur content of 1.75%, and is solid at room temperature. Attention should be paid to clogging of the pipings. The overall efficiency is 80%. The combined cogeneration can be coordinated with load variations of 10 - 20%. (12 figs, 1 tab)

  10. A method to evaluate fission gas release during irradiation testing of spherical fuel - HTR2008-58184

    International Nuclear Information System (INIS)

    Van Der Merwet, H.; Venter, J.

    2008-01-01

    The evaluation of fission gas release from spherical fuel during irradiation testing is critical to understand expected fuel performance under real reactor conditions. Online measurements of Krypton and Xenon fission products explain coated particle performance and contributions from graphitic matrix materials used in fuel manufacture and irradiation rig materials. Methods that are being developed to accurately evaluate fission gas release are described here together with examples of evaluations performed on irradiation tests HFR-K5, -K6 and EU1bis. (authors)

  11. The long term release of heavy metals from combustion residues and slags

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, J.N.

    1996-12-31

    This treatise details methodology which may be used to construct a model of the geochemical evolution in a waste repository and the changes in leachate composition over time. The pH and Eh of the leachant, as well as major complexing anions control the leaching of heavy metals over very long times due to solubility constraints. The pH and the Eh of the leachate changes when the buffering capacity of the waste has been exhausted. It is possible that the altered pH and Eh conditions in the leachate at later times may allow leaching of heavy metals at considerably higher concentrations than those present earlier during the leaching process. The model developed requires data which may be obtained from simple laboratory experiments in order to describe the reactive properties of the waste. Because of the complexity of the real system, the model uses `generalised` minerals which react with the inflowing oxygen and acidity to buffer the pH and Eh of the leachant. In this way, the chemistry of the leachant may be modelled without the need for a detailed geochemical description of the waste material. The model is intended to be simple and flexible enough that it may be adapted to different waste types with reasonable ease. The results obtained indicate that the redox and the pH-buffering characteristics of the waste are very important in determining the leaching of trace metals. The results also illustrate the strong influence that diffusional transport of CO{sub 2} and O{sub 2} may have upon the long term leaching behaviour. The model predictions have not, as yet, been reconciled with field leachate measurements. This will form a major part of the continued work with this project 38 refs, 63 figs, 11 tabs

  12. Modeling of Oceanic Gas Hydrate Instability and Methane Release in Response to Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Reagan, Matthew; Reagan, Matthew T.; Moridis, George J.

    2008-04-15

    Paleooceanographic evidence has been used to postulate that methane from oceanic hydrates may have had a significant role in regulating global climate, implicating global oceanic deposits of methane gas hydrate as the main culprit in instances of rapid climate change that have occurred in the past. However, the behavior of contemporary oceanic methane hydrate deposits subjected to rapid temperature changes, like those predicted under future climate change scenarios, is poorly understood. To determine the fate of the carbon stored in these hydrates, we performed simulations of oceanic gas hydrate accumulations subjected to temperature changes at the seafloor and assessed the potential for methane release into the ocean. Our modeling analysis considered the properties of benthic sediments, the saturation and distribution of the hydrates, the ocean depth, the initial seafloor temperature, and for the first time, estimated the effect of benthic biogeochemical activity. The results show that shallow deposits--such as those found in arctic regions or in the Gulf of Mexico--can undergo rapid dissociation and produce significant methane fluxes of 2 to 13 mol/yr/m{sup 2} over a period of decades, and release up to 1,100 mol of methane per m{sup 2} of seafloor in a century. These fluxes may exceed the ability of the seafloor environment (via anaerobic oxidation of methane) to consume the released methane or sequester the carbon. These results will provide a source term to regional or global climate models in order to assess the coupling of gas hydrate deposits to changes in the global climate.

  13. The effect of UO2 density on fission product gas release and sheath expansion

    International Nuclear Information System (INIS)

    Notley, M.J.F.; MacEwan, J.R.

    1965-03-01

    The effect of UO 2 density on fission product gas release and sheath expansion has been determined in an irradiation experiment in which the performance of fuel elements with densities between 10.42 and 10.74 g/cm 3 was compared at ∫λdθ values of 39 and 42 W/cm. The elements were irradiated as clusters of four in a pressurized water loop, hence their irradiation histories were identical. Fission product gas release and the extend of grain growth were greater for the lower density elements. Both effects can be attributed solely to the variation of the thermal conductivity of the fuel with the fractional porosity p, if λ p λ [1 - (2.6 ± 0.8) p] where λ is the thermal conductivity of fully dense UO 2 and λ p is that of the porous UO 2 . This expression is in agreement with laboratory findings. A correlation between the extent of grain growth in the UO 2 and the fractional gas release was found to exist in this test and was shown to apply in a large number of other fuel irradiations. Diametral sheath strain was lower for the low density fuel elements than for those of high density, although the former were deduced to have operated with higher central temperatures. It is supposed that the thermal expansion of the fuel can be partially accommodated by elimination of some of the original porosity. The data are consistent with the assumption that approximately half the porosity in the region of the fuel undergoing grain growth is eliminated. (author)

  14. Hydrogen Gas Retention and Release from WTP Vessels: Summary of Preliminary Studies

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, Phillip A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bontha, Jagannadha R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Daniel, Richard C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mahoney, Lenna A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rassat, Scot D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wells, Beric E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bao, Jie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Boeringa, Gregory K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buchmiller, William C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burns, Carolyn A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chun, Jaehun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Karri, Naveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Li, Huidong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tran, Diana N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-01

    The Hanford Waste Treatment and Immobilization Plant (WTP) is currently being designed and constructed to pretreat and vitrify a large portion of the waste in the 177 underground waste storage tanks at the Hanford Site. A number of technical issues related to the design of the pretreatment facility (PTF) of the WTP have been identified. These issues must be resolved prior to the U.S. Department of Energy (DOE) Office of River Protection (ORP) reaching a decision to proceed with engineering, procurement, and construction activities for the PTF. One of the issues is Technical Issue T1 - Hydrogen Gas Release from Vessels (hereafter referred to as T1). The focus of T1 is identifying controls for hydrogen release and completing any testing required to close the technical issue. In advance of selecting specific controls for hydrogen gas safety, a number of preliminary technical studies were initiated to support anticipated future testing and to improve the understanding of hydrogen gas generation, retention, and release within PTF vessels. These activities supported the development of a plan defining an overall strategy and approach for addressing T1 and achieving technical endpoints identified for T1. Preliminary studies also supported the development of a test plan for conducting testing and analysis to support closing T1. Both of these plans were developed in advance of selecting specific controls, and in the course of working on T1 it was decided that the testing and analysis identified in the test plan were not immediately needed. However, planning activities and preliminary studies led to significant technical progress in a number of areas. This report summarizes the progress to date from the preliminary technical studies. The technical results in this report should not be used for WTP design or safety and hazards analyses and technical results are marked with the following statement: “Preliminary Technical Results for Planning – Not to be used for WTP Design

  15. Fission-gas release in fuel performing to extended burnups in Ontario Hydro nuclear generating stations

    International Nuclear Information System (INIS)

    Floyd, M.R.; Novak, J.; Truant, P.T.

    1992-06-01

    The average discharge burnup of CANDU fuel is about 200 MWh/kgU. A significant number of 37-element bundles have achieved burnups in excess of 400 MWh/kgU. Some of these bundles have experienced failures related to their extended operation. To date, hot-cell examinations have been performed on fuel elements from nine 37-element bundles irradiated in Bruce NGS-A that have burnups in the range of 300-800 MWh/kgU. 1 Most of these have declining power histories from peak powers of up to 59 kW/m. Fission-gas releases of up to 26% have been observed and exhibit a strong dependence on fuel power. This obscures any dependence on burnup. The extent of fission-gas release at extended burnups was not predicted by low-burnup code extrapolations. This is attributed primarily to a reduction in fuel thermal conductivity which results in elevated operating temperatures. Reduced conductivity is due, at least in part, to the buildup of fission products in the fuel matrix. Some evidence of hyperstoichiometry exists, although this needs to be further investigated along with any possible relation to CANLUB graphite coating behaviour and sheath oxidation. Residual tensile sheath strains of up to 2% have been observed and can be correlated with fuel power/fission-gas release. SCC 2 -related defects have been observed in the sheath and endcaps of elements from bundles experiencing declining power histories to burnups in excess of 500 MWh/kgU. This indicates that the current recommended burnup limit of 450 MWh/kgU is justified. SCC-related defects have also been observed in ramped bundles having burnups < 450 MWh/kgU. Hence, additional guidelines are in place for power ramping extended-burnup fuel

  16. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL). Part 5. Accidental Releases

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, S

    2007-08-15

    Over the course of fifty-three years, LLNL had six acute releases of tritiated hydrogen gas (HT) and one acute release of tritiated water vapor (HTO) that were too large relative to the annual releases to be included as part of the annual releases from normal operations detailed in Parts 3 and 4 of the Tritium Dose Reconstruction (TDR). Sandia National Laboratories/California (SNL/CA) had one such release of HT and one of HTO. Doses to the maximally exposed individual (MEI) for these accidents have been modeled using an equation derived from the time-dependent tritium model, UFOTRI, and parameter values based on expert judgment. All of these acute releases are described in this report. Doses that could not have been exceeded from the large HT releases of 1965 and 1970 were calculated to be 43 {micro}Sv (4.3 mrem) and 120 {micro}Sv (12 mrem) to an adult, respectively. Two published sets of dose predictions for the accidental HT release in 1970 are compared with the dose predictions of this TDR. The highest predicted dose was for an acute release of HTO in 1954. For this release, the dose that could not have been exceeded was estimated to have been 2 mSv (200 mrem), although, because of the high uncertainty about the predictions, the likely dose may have been as low as 360 {micro}Sv (36 mrem) or less. The estimated maximum exposures from the accidental releases were such that no adverse health effects would be expected. Appendix A lists all accidents and large routine puff releases that have occurred at LLNL and SNL/CA between 1953 and 2005. Appendix B describes the processes unique to tritium that must be modeled after an acute release, some of the time-dependent tritium models being used today, and the results of tests of these models.

  17. Assessing and Projecting Greenhouse Gas Release due to Abrupt Permafrost Degradation

    Science.gov (United States)

    Saito, K.; Ohno, H.; Yokohata, T.; Iwahana, G.; Machiya, H.

    2017-12-01

    Permafrost is a large reservoir of frozen soil organic carbon (SOC; about half of all the terrestrial storage). Therefore, its degradation (i.e., thawing) under global warming may lead to a substantial amount of additional greenhouse gas (GHG) release. However, understanding of the processes, geographical distribution of such hazards, and implementation of the relevant processes in the advanced climate models are insufficient yet so that variations in permafrost remains one of the large source of uncertainty in climatic and biogeochemical assessment and projections. Thermokarst, induced by melting of ground ice in ice-rich permafrost, leads to dynamic surface subsidence up to 60 m, which further affects local and regional societies and eco-systems in the Arctic. It can also accelerate a large-scale warming process through a positive feedback between released GHGs (especially methane), atmospheric warming and permafrost degradation. This three-year research project (2-1605, Environment Research and Technology Development Fund of the Ministry of the Environment, Japan) aims to assess and project the impacts of GHG release through dynamic permafrost degradation through in-situ and remote (e.g., satellite and airborn) observations, lab analysis of sampled ice and soil cores, and numerical modeling, by demonstrating the vulnerability distribution and relative impacts between large-scale degradation and such dynamic degradation. Our preliminary laboratory analysis of ice and soil cores sampled in 2016 at the Alaskan and Siberian sites largely underlain by ice-rich permafrost, shows that, although gas volumes trapped in unit mass are more or less homogenous among sites both for ice and soil cores, large variations are found in the methane concentration in the trapped gases, ranging from a few ppm (similar to that of the atmosphere) to hundreds of thousands ppm We will also present our numerical approach to evaluate relative impacts of GHGs released through dynamic

  18. The critical release rates for the dissociating gas N204/N02/N0

    International Nuclear Information System (INIS)

    Porter, W.H.L.

    1979-03-01

    Dissociating vapour systems have certain characteristics which make them attractive as coolants, notably a large effective specific heat which is significantly greater than that for the individual components of the gas mixture, and also an enhanced boundary layer heat transfer coefficient resulting from the physical characteristics of thermal dissociation. In part these effects ensure that a dissociating gas has a greatly improved thermal capacity and heat transfer capability when compared with most inert gases. In this report the critical release rates for the dissociating vapour system N 2 0 4 -N0 2 -N0 are established, principally in the two phase region, and the thermodynamics of nitrogen tetroxide are examined. (U.K.)

  19. Stimuli-Responsive NO Release for On-Demand Gas-Sensitized Synergistic Cancer Therapy.

    Science.gov (United States)

    Fan, Wenpei; Yung, Bryant C; Chen, Xiaoyuan

    2018-03-08

    Featuring high biocompatibility, the emerging field of gas therapy has attracted extensive attention in the medical and scientific communities. Currently, considerable research has focused on the gasotransmitter nitric oxide (NO) owing to its unparalleled dual roles in directly killing cancer cells at high concentrations and cooperatively sensitizing cancer cells to other treatments for synergistic therapy. Of particular note, recent state-of-the-art studies have turned our attention to the chemical design of various endogenous/exogenous stimuli-responsive NO-releasing nanomedicines and their biomedical applications for on-demand NO-sensitized synergistic cancer therapy, which are discussed in this Minireview. Moreover, the potential challenges regarding NO gas therapy are also described, aiming to advance the development of NO nanomedicines as well as usher in new frontiers in this fertile research area. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste

    International Nuclear Information System (INIS)

    Wells, Beric E.; Cuta, Judith M.; Hartley, Stacey A.; Mahoney, Lenna A.; Meyer, Perry A.; Stewart, Charles W.

    2002-01-01

    Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105, and AW-101 to the vitrification plant beginning about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both of these operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernatant decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated

  1. Gas density and rail pressure effects on diesel spray growth from a heavy-duty common rail injector

    NARCIS (Netherlands)

    Klein-Douwel, R.J.H.; Frijters, P.J.M.; Seykens, X.L.J.; Somers, L.M.T.; Baert, R.S.G.

    2009-01-01

    Formation of nonevaporating sprays from diesel fuel injection through a realistic heavy duty multihole common rail injector is studied in a newly developed high-pressure, high-temperature cell, using digital highspeed shadowgraphy at 4500 frames/s. Gas pressure was varied from 13 to 37 bar

  2. Gas density and rail pressure effects on diesel spray growth from a heavy-duty common rail injector

    NARCIS (Netherlands)

    Klein-Douwel, R.J.H.; Frijters, P.J.M.; Seykens, X.L.J.; Somers, L.M.T.; Baert, R.S.G.

    2009-01-01

    Formation of nonevaporating sprays from diesel fuel injection through a realistic heavy duty multihole common rail injector is studied in a newly developed high-pressure, high-temperature cell, using digital high-speed shadowgraphy at 4500 frames/s. Gas pressure was varied from 13 to 37 bar

  3. A microstructure-dependent model for fission product gas release and swelling in UO2 fuel

    International Nuclear Information System (INIS)

    Notley, M.J.F.; Hastings, I.J.

    1979-06-01

    A model for the release of fission gas from irradiated UO2 fuel is presented. It incorporates fission gas diffusion bubble and grain boundary movement,intergranular bubble formation and interlinkage. In addition, the model allows estimates of the extent of structural change and fuel swelling. In the latter, contributions of thermal expansion, densification, solid fission products, and gas bubbles are considered. When included in the ELESIM fuel performance code, the model yields predictions which are in good agreement with data from UO2 fuel elements irradiated over a range of water-cooled reactor conditions: linear power outputs between 40 and 120 kW/m, burnups between 10 and 300 MW.h/kg U and power histories including constant, high-to-low and low-to-high power periods. The predictions of the model are shown to be most sensitive to fuel power (temperature), the selection of diffusion coefficient for fission gas in UO2 and burnup. The predictions are less sensitive to variables such as fuel restraint, initial grain size and the rate of grain growth. (author)

  4. A New Superalloy Enabling Heavy Duty Gas Turbine Wheels for Improved Combined Cycle Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Detor, Andrew [General Electric Company, Niskayuna, NY (United States). GE Global Research; DiDomizio, Richard [General Electric Company, Niskayuna, NY (United States). GE Global Research; McAllister, Don [The Ohio State Univ., Columbus, OH (United States); Sampson, Erica [General Electric Company, Niskayuna, NY (United States). GE Global Research; Shi, Rongpei [The Ohio State Univ., Columbus, OH (United States); Zhou, Ning [General Electric Company, Niskayuna, NY (United States). GE Global Research

    2017-01-03

    The drive to increase combined cycle turbine efficiency from 62% to 65% for the next-generation advanced cycle requires a new heavy duty gas turbine wheel material capable of operating at 1200°F and above. Current wheel materials are limited by the stability of their major strengthening phase (gamma double prime), which coarsens at temperatures approaching 1200°F, resulting in a substantial reduction in strength. More advanced gamma prime superalloys, such as those used in jet engine turbine disks, are also not suitable due to size constraints; the gamma prime phase overages during the slow cooling rates inherent in processing thick-section turbine wheels. The current program addresses this need by screening two new alloy design concepts. The first concept exploits a gamma prime/gamma double prime coprecipitation reaction. Through manipulation of alloy chemistry, coprecipitation is controlled such that gamma double prime is used only to slow the growth of gamma prime during slow cooling, preventing over-aging, and allowing for subsequent heat treatment to maximize strength. In parallel, phase field modeling provides fundamental understanding of the coprecipitation reaction. The second concept uses oxide dispersion strengthening to improve on two existing alloys that exhibit excellent hold time fatigue crack growth resistance, but have insufficient strength to be considered for gas turbine wheels. Mechanical milling forces the dissolution of starting oxide powders into a metal matrix allowing for solid state precipitation of new, nanometer scale oxides that are effective at dispersion strengthening.

  5. Gas Transport and Density Control in the HYLIFE Heavy-Ion Beam Lines

    International Nuclear Information System (INIS)

    Debonnel, Christophe S.; Welch, Dale R.; Rose, David V.; Lawrence, Simon S.Yu; Peterson, Per F.

    2003-01-01

    The effective propagation and focusing of heavy-ion beams in the final-focus magnet region of inertial fusion target chambers require controlling the background gas density and pressure in the beam tubes. Liquid vortexes will coat the inside of the tubes next to the beam ports and will help eliminate the need for mechanical shutters to mitigate the venting of target chamber background gas into the final-focus magnet region. Before the neutralizing region, the beam space charge is high, and ablation and target debris deposition in the final-focus magnet region may cause voltage breakdown. Previous studies focused on evaluating the amount of target chamber debris reaching the entrance of the beam ports. The TSUNAMI code has now been used to assess the density, temperature, and velocity of the vortex debris transported ∼3 m up the beam tubes and reaching the final-focus magnet region, assuming that the liquid vortexes are perfectly absorbing surfaces. To further mitigate debris deposition in the final-focus magnet region, and prevent voltage breakdown, a 'magnetic shutter' has been envisaged to divert the debris out of the final-focus region. This shutter will prevent the hot ablation debris from reaching the magnet region and, coupled to some ionizing scheme, will conveniently suppress early ingression of debris into the final-focus magnet region

  6. A study on the transfer of heavy methals released by Chinese commercial products.

    Science.gov (United States)

    Olori, Angelo; Campopiano, Antonella; Cannizzaro, Annapaola; Basili, Fulvio

    2013-01-01

    Studies by The World trade Organization (WTO) and the Organization for the Economic Cooperation and Development (OECD) state that the trade on counterfeit goods corresponds to 10% of the global trade and it is worth 450 billion dollars. In this work we studied the transfer of toxic metals released by some Chinese watches causing significant allergic dermatitis. Several samples of dust released from metal parts got collected. Such powders were observed at the Electron Microscope complete with EDAX spectrometer. In all the studied dust samples we identified the following chemical elements: Cu, Ni and Zn. The SEM analysis has identified two predominant phases such as pure nickel and brass alloy (Cu-Zn). The first metal subjected to cession and to corrosion phenomena is nickel. The main causes of corrosion in the studied materials were due to the presence of chloride ions. Among the ceased metals found in our study nickel is the most dangerous. Scientific evidence now agree that nickel and certain nickel compounds are toxic and highly harmful to human health they indeed cause allergic contact dermatitis (DAC).

  7. A Meta-Analysis of the Efficacy of Bupropion Sustained-Release for Smoking Cessation in Heavy Smokers

    Directory of Open Access Journals (Sweden)

    Adrian Paszek

    2017-09-01

    Full Text Available Cigarette smoking damages just about every organ in the body and reduces overall health. Even with the prevalence of accessible nicotine replacement therapies and behavioral counseling, there remains a need for alternative therapies to improve the odds of successfully abstaining from smoking in the long term. Bupropion sustained-release (SR is a pharmacological, prescription-only intervention that is approved as a first-line treatment for smoking cessation. This meta-analysis examines the effectiveness of bupropion sustained-release for smoking cessation amongst heavy smokers, defined as those who consistently smoke at least fifteen or more cigarettes per day. Across five qualifying studies, bupropion SR increased odds of cessation over placebo treatment at six and twelve months. Bupropion SR is a well-tolerated, non-nicotinic therapy for smoking cessation. Treatment with bupropion SR reduces initial cravings and withdrawal effects but does not appear to address the multi-faceted problem of cigarette addiction, resulting in decreased abstinence rates over time. An integrated approach incorporating bupropion SR with other interventions, such as nicotine replacement therapies and psychotherapy, may provide the necessary means to achieve lasting cessation and promote well-being.

  8. Swelling and gas release of grain-boundary pores in uranium dioxide

    International Nuclear Information System (INIS)

    Schrire, D.I.

    1983-12-01

    The swelling and gas release of overpressured grain boundary pores is sintered unirradiated uranium dioxide were investigated under isothermal conditions. The pores became overpressured when the ambient pressure was reduced, and the excess pressure driving force caused growth and interconnection of the pores, leading to eventual gas release. Swelling was measured continuously by a linear variable differential transformer, and open and closed porosity fractions were determined after the tests by immersion density and quantitative microscopy measurements. The sinter porosity consisted of pores situated on grain faces, grain edges, and grain corners. Isolated pores maintained their equilibrium shape while growing, without any measurable change in dihedral angle. Interconnection occurred predominantly along grain edges, without any evidence of pore sharpening or crack propagation at low driving forces. Extensive open porosity occurred at a threshold density of about 85% TD. There was an almost linear dependence of the initial swelling rate on the driving force, with an activation energy of 200+- 8 kJ/mole, in good agreement with published values of the activation energy for grain boundary diffusion

  9. A Gas Target Internal to the LHC for the Study of pp Single-Spin Asymmetries and Heavy Ion Collisions

    Directory of Open Access Journals (Sweden)

    Colin Barschel

    2015-01-01

    Full Text Available We discuss the application of an open storage cell as gas target for a proposed LHC fixed-target experiment AFTER@LHC. The target provides a high areal density at minimum gas input, which may be polarized 1H, 2H, or 3He gas or heavy inert gases in a wide mass range. For the study of single-spin asymmetries in pp interaction, luminosities of nearly 1033/cm2 s can be produced with existing techniques.

  10. Environmental effects of a tritium gas release from the Savannah River Plant on December 31, 1975

    International Nuclear Information System (INIS)

    Jacobsen, W.R.

    1976-03-01

    At 10:00 p.m. EST on December 31, 1975, 182,000 Ci of tritium gas was released within about 1.5 min from a tritium processing facility at the Savannah River Plant. The release was caused by the failure of a vacuum gage and was exhausted to the atmosphere by way of a 200-ft-high stack. Winds averaging 20 mph carried the tritium offplant toward the east. Calculations indicate that the puff passed out to sea about 35 miles north of Charleston, South Carolina, about 7 hr after the release occurred. Samples from the facility exhaust system indicated that 99.4 percent of the tritium was in elemental form and 0.6 percent was in the more biologically active oxide (water) form. The maximum potential dose to a person (from inhalation and skin absorption) at the puff centerline on the plant boundary was calculated to be 0.014 mrem, or about 0.01 percent of the annual dose received from natural radioactivity. The integrated dose to the population under the release path was calculated to be 0.2 man-rem before the tritium passed out to sea. Over 300 environmental samples were collected and analyzed following the release. These samples included air moisture, atmospheric hydrogen, vegetation, soil, surface water, milk, and human urine. Positive results were obtained in some onplant and plant perimeter samples; these results aided in confirming the close-in puff trajectory. Tritium concentrations in nearly all samples taken beyond the plant perimeter fell within normal ranges; no urine samples indicated any tritium uptakes as a result of the release. Two milk samples did indicate a measurable tritium uptake; the maximum potential dose to an individual drinking this milk was calculated to be about 0.1 mrem. Because calculated doses from assumed exposure to the tritium are low and analyses of environmental samples indicated no significant accumulation of tritium, it is concluded that no significant environmental effects resulted from the December 31, 1975, tritium release

  11. Formulation and evaluation of gas release scenarios for the silo in Swedish Final Repository for Radioactive Waste (SFR)

    International Nuclear Information System (INIS)

    Carlsson, J.; Moreno, L.

    1992-01-01

    The Swedish Final Repository for Radioactive Waste (SFR) has been in operation since 1988 and is located in the crystalline rock, 60 m below the Baltic Sea. In the licensing procedure for the SFR the safety assessment has been complemented with a detailed scenario analysis of the performance of the repository. The scenarios include the influence on radionuclide release by gas formation and gas transport processes in the silo. The overall conclusion is that the release of most radionuclides from the silo is only marginally affected by the formation and release of gas, even for scenarios considering unexpected events. The largest effects were found for short-lived radionuclides and radionuclides that have no or low sorption ability. Except for very extreme scenarios for the silo the overall impact from repository on the environment is by far dominated by the release of radionuclides from the rock vaults. 10 refs., 6 figs

  12. Adequate Measuring Technology and System of Fission Gas release Behavior from Voloxidation Process

    International Nuclear Information System (INIS)

    Park, Geun Il; Park, J. J.; Jung, I. H.; Shin, J. M.; Yang, M. S.; Song, K. C.

    2006-09-01

    Based on the published literature and an understanding of available hot cell technologies, more accurate measuring methods for each volatile fission product released from voloxidation process were reviewed and selected. The conceptual design of an apparatus for measuring volatile and/or semi-volatile fission products released from spent fuel was prepared. It was identified that on-line measurement techniques can be applied for gamma-emitting fission products, and off-line measurement such as chemical/or neutron activation analysis can applied for analyzing beta-emitting fission gases. Collection methods using appropriate material or solutions were selected to measure the release fraction of beta-emitting gaseous fission products at IMEF M6 hot cell. Especially, the on-line gamma-ray counting system for monitoring of 85Kr and the off-line measuring system of 14C was established. On-line measuring system for obtaining removal ratios of the semi-volatile fission products, mainly gamma-emitting fission products such as Cs, Ru etc., was also developed at IMEF M6 hot cell which was based on by measuring fuel inventory before and after the voloxidation test through gamma measuring technique. The development of this measurement system may enable basic information to be obtained to support design of the off-gas treatment system for the voloxidation process at INL, USA

  13. Influence of additives and impurities in sweep gas and solid tritium release behaviour from lithium ceramics (review)

    International Nuclear Information System (INIS)

    Tanaka, Satoru

    1991-01-01

    Tritium release from solid breeding material is affected by small amounts of additives or impurities in the sweep gas or solid itself. Addition of hydrogen or water vapor to the sweep gas is reported to enhance the surface reaction of tritium release. Doping to solid breeder with elements of different valence from lithium has a possibility to improve tritium diffusion in the solid. Surface reaction and migration behavior in bulk are believed to be also affected by impurities in the sweep gas and in the solid. In order to model tritium release behavior in the blanket of fusion reactor, the mechanism of interaction with these additives or impurities must be quantitatively formulated. However, the mechanism of these remains to be elucidated. In this paper effects of these additives and impurities on tritium migration are reviewed. The mechanism of surface reaction for He+H 2 sweep gas is also discussed. (orig.)

  14. Calculations of Fission Gas Release During Ramp Tests Using Copernic Code

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Liu [Nuclear Fuel R and D Center, China Nuclear Power Technology Research Institute (CNPRI) (China)

    2013-03-15

    The report performed under IAEA research contract No.15951 describes the results of fuel performance evaluation of LWR fuel rods operated at ramp conditions using the COPERNIC code developed by AREVA. The experimental data from the Third Riso Fission Gas Project and the Studsvik SUPER-RAMP Project presented in the IFPE database of the OECD/NEA has been utilized for assessing the code itself during simulation of fission gas release (FGR). Standard code models for LWR fuel were used in simulations with parameters set properly in accordance with relevant test reports. With the help of data adjustment, the input power histories are restructured to fit the real ones, so as to ensure the validity of FGR prediction. The results obtained by COPERNIC show that different models lead to diverse predictions and discrepancies. By comparison, the COPERNIC V2.2 model (95% Upper bound) is selected as the standard FGR model in this report and the FGR phenomenon is properly simulated by the code. To interpret the large discrepancies of some certain PK rods, the burst effect of FGR which is taken into consideration in COPERNIC is described and the influence of the input power histories is extrapolated. In addition, the real-time tracking capability of COPERNIC is tested against experimental data. In the process of investigation, two main dominant factors influencing the measured gas release rate are described and different mechanisms are analyzed. With the limited predicting capacity, accurate predictions cannot be carried out on abrupt changes of FGR during ramp tests by COPERNIC and improvements may be necessary to some relevant models. (author)

  15. Idle emissions from heavy-duty diesel and natural gas vehicles at high altitude.

    Science.gov (United States)

    McCormick, R L; Graboski, M S; Alleman, T L; Yanowitz, J

    2000-11-01

    Idle emissions of total hydrocarbon (THC), CO, NOx, and particulate matter (PM) were measured from 24 heavy-duty diesel-fueled (12 trucks and 12 buses) and 4 heavy-duty compressed natural gas (CNG)-fueled vehicles. The volatile organic fraction (VOF) of PM and aldehyde emissions were also measured for many of the diesel vehicles. Experiments were conducted at 1609 m above sea level using a full exhaust flow dilution tunnel method identical to that used for heavy-duty engine Federal Test Procedure (FTP) testing. Diesel trucks averaged 0.170 g/min THC, 1.183 g/min CO, 1.416 g/min NOx, and 0.030 g/min PM. Diesel buses averaged 0.137 g/min THC, 1.326 g/min CO, 2.015 g/min NOx, and 0.048 g/min PM. Results are compared to idle emission factors from the MOBILE5 and PART5 inventory models. The models significantly (45-75%) overestimate emissions of THC and CO in comparison with results measured from the fleet of vehicles examined in this study. Measured NOx emissions were significantly higher (30-100%) than model predictions. For the pre-1999 (pre-consent decree) truck engines examined in this study, idle NOx emissions increased with model year with a linear fit (r2 = 0.6). PART5 nationwide fleet average emissions are within 1 order of magnitude of emissions for the group of vehicles tested in this study. Aldehyde emissions for bus idling averaged 6 mg/min. The VOF averaged 19% of total PM for buses and 49% for trucks. CNG vehicle idle emissions averaged 1.435 g/min for THC, 1.119 g/min for CO, 0.267 g/min for NOx, and 0.003 g/min for PM. The g/min PM emissions are only a small fraction of g/min PM emissions during vehicle driving. However, idle emissions of NOx, CO, and THC are significant in comparison with driving emissions.

  16. Measurement of fission gas release, internal pressure and cladding creep rate in the fuel pins of PHWR bundle of normal discharge burnup

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, U.K. [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Sah, D.N., E-mail: dnsah@barc.gov.i [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Rath, B.N.; Anantharaman, S. [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2009-08-01

    Fuel pins of a Pressurised Heavy Water Reactor (PHWR) fuel bundle discharged from Narora Atomic Power Station unit no. 1 after attaining a fuel burnup of 7528 MWd/tU have been subjected to two types of studies, namely (i) puncture test to estimate extent of fission gas release and internal pressure in the fuel pin and (ii) localized heating of the irradiated fuel pin to measure the creep rate of the cladding in temperature range 800 deg. C - 900 deg. C. The fission gas release in the fuel pins from the outer ring of the bundle was found to be about 8%. However, only marginal release was found in fuel pins from the middle ring and the central fuel pin. The internal gas pressure in the outer fuel pin was measured to be 0.55 +- 0.05 MPa at room temperature. In-cell isothermal heating of a small portion of the outer fuel pins was carried out at 800 deg. C, 850 deg. C and 900 deg. C for 10 min and the increase in diameter of the fuel pin was measured after heat treatment. Creep rates of the cladding obtained from the measurement of the diameter change of the cladding due to heating at 800 deg. C, 850 deg. C and 900 deg. C were found respectively to be 2.4 x 10{sup -5} s{sup -1}, 24.6 x 10{sup -5} s{sup -1} and 45.6 x 10{sup -5} s{sup -1}.

  17. Mechanisms of gas retention and release: Experimental results for Hanford waste tanks 241-AW-101 and 241-AN-103

    Energy Technology Data Exchange (ETDEWEB)

    Rassat, S.D.; Gauglitz, P.A.; Bredt, P.R.; Mahoney, L.A.; Forbes, S.V.; Tingey, S.M.

    1997-09-01

    The 177 storage tanks at Hanford contain a vast array of radioactive waste forms resulting, primarily, from nuclear materials processing. Through radiolytic, thermal, and other decomposition reactions of waste components, gaseous species including hydrogen, ammonia, and the oxidizer nitrous oxide are generated within the waste tanks. Many of these tanks are known to retain and periodically release quantities of these flammable gas mixtures. The primary focus of the Flammable Gas Project is the safe storage of Hanford tank wastes. To this end, we strive to develop an understanding of the mechanisms of flammable gas retention and release in Hanford tanks through laboratory investigations on actual tank wastes. These results support the closure of the Flammable Gas Unreviewed Safety Question (USQ) on the safe storage of waste tanks known to retain flammable gases and support resolution of the broader Flammable Gas Safety Issue. The overall purpose of this ongoing study is to develop a comprehensive and thorough understanding of the mechanisms of flammable gas retention and release. The first objective of the current study was to classify bubble retention and release mechanisms in two previously untested waste materials from Tanks 241-AN-103 (AN-103) and 241-AW-101 (AW-101). Results were obtained for retention mechanisms, release characteristics, and the maximum gas retention. In addition, unique behavior was also documented and compared with previously studied waste samples. The second objective was to lengthen the duration of the experiments to evaluate the role of slowing bubble growth on the retention and release behavior. Results were obtained for experiments lasting from a few hours to a few days.

  18. Mechanisms of gas retention and release: Experimental results for Hanford waste tanks 241-AW-101 and 241-AN-103

    International Nuclear Information System (INIS)

    Rassat, S.D.; Gauglitz, P.A.; Bredt, P.R.; Mahoney, L.A.; Forbes, S.V.; Tingey, S.M.

    1997-09-01

    The 177 storage tanks at Hanford contain a vast array of radioactive waste forms resulting, primarily, from nuclear materials processing. Through radiolytic, thermal, and other decomposition reactions of waste components, gaseous species including hydrogen, ammonia, and the oxidizer nitrous oxide are generated within the waste tanks. Many of these tanks are known to retain and periodically release quantities of these flammable gas mixtures. The primary focus of the Flammable Gas Project is the safe storage of Hanford tank wastes. To this end, we strive to develop an understanding of the mechanisms of flammable gas retention and release in Hanford tanks through laboratory investigations on actual tank wastes. These results support the closure of the Flammable Gas Unreviewed Safety Question (USQ) on the safe storage of waste tanks known to retain flammable gases and support resolution of the broader Flammable Gas Safety Issue. The overall purpose of this ongoing study is to develop a comprehensive and thorough understanding of the mechanisms of flammable gas retention and release. The first objective of the current study was to classify bubble retention and release mechanisms in two previously untested waste materials from Tanks 241-AN-103 (AN-103) and 241-AW-101 (AW-101). Results were obtained for retention mechanisms, release characteristics, and the maximum gas retention. In addition, unique behavior was also documented and compared with previously studied waste samples. The second objective was to lengthen the duration of the experiments to evaluate the role of slowing bubble growth on the retention and release behavior. Results were obtained for experiments lasting from a few hours to a few days

  19. Development of intense pulsed heavy ion beam diode using gas puff plasma gun as ion source

    International Nuclear Information System (INIS)

    Ito, H.; Higashiyama, M.; Takata, S.; Kitamura, I.; Masugata, K.

    2006-01-01

    A magnetically insulated ion diode with an active ion source of a gas puff plasma gun has been developed in order to generate a high-intensity pulsed heavy ion beam for the implantation process of semiconductors and the surface modification of materials. The nitrogen plasma produced by the plasma gun is injected into the acceleration gap of the diode with the external magnetic field system. The ion diode is operated at diode voltage approx. =200 kV, diode current approx. =2 kA and pulse duration approx. =150 ns. A new acceleration gap configuration for focusing ion beam has been designed in order to enhance the ion current density. The experimental results show that the ion current density is enhanced by a factor of 2 and the ion beam has the ion current density of 27 A/cm 2 . In addition, the coaxial type Marx generator with voltage 200 kV and current 15 kA has been developed and installed in the focus type ion diode. The ion beam of ion current density approx. =54 A/cm 2 is obtained. To produce metallic ion beams, an ion source by aluminum wire discharge has been developed and the aluminum plasma of ion current density ∼70 A/cm 2 is measured. (author)

  20. Total fuel-cycle analysis of heavy-duty vehicles using biofuels and natural gas-based alternative fuels.

    Science.gov (United States)

    Meyer, Patrick E; Green, Erin H; Corbett, James J; Mas, Carl; Winebrake, James J

    2011-03-01

    Heavy-duty vehicles (HDVs) present a growing energy and environmental concern worldwide. These vehicles rely almost entirely on diesel fuel for propulsion and create problems associated with local pollution, climate change, and energy security. Given these problems and the expected global expansion of HDVs in transportation sectors, industry and governments are pursuing biofuels and natural gas as potential alternative fuels for HDVs. Using recent lifecycle datasets, this paper evaluates the energy and emissions impacts of these fuels in the HDV sector by conducting a total fuel-cycle (TFC) analysis for Class 8 HDVs for six fuel pathways: (1) petroleum to ultra low sulfur diesel; (2) petroleum and soyoil to biodiesel (methyl soy ester); (3) petroleum, ethanol, and oxygenate to e-diesel; (4) petroleum and natural gas to Fischer-Tropsch diesel; (5) natural gas to compressed natural gas; and (6) natural gas to liquefied natural gas. TFC emissions are evaluated for three greenhouse gases (GHGs) (carbon dioxide, nitrous oxide, and methane) and five other pollutants (volatile organic compounds, carbon monoxide, nitrogen oxides, particulate matter, and sulfur oxides), along with estimates of total energy and petroleum consumption associated with each of the six fuel pathways. Results show definite advantages with biodiesel and compressed natural gas for most pollutants, negligible benefits for e-diesel, and increased GHG emissions for liquefied natural gas and Fischer-Tropsch diesel (from natural gas).

  1. On-line mass spectrometry measurement of fission gas release from nuclear fuel submitted to thermal transients

    International Nuclear Information System (INIS)

    Guigues, E.; Janulyte, A.; Zerega, Y.; Pontillon, Y.

    2013-06-01

    The work presented in this paper has been performed in the framework of a joint research program between Aix-Marseille University and CEA Cadarache. The aim is to develop a mass spectrometer (MS) device for the MERARG facility. MERARG is devoted to the study of fission gas release measurement, from nuclear fuels submitted to annealing tests in high activity laboratory such as LECA-STAR, thanks to gamma spectrometry. The mass spectrometer will then extend the measurement capability from the γ-emitters gases to all the gases involved in the release in order to have a better understanding of the fission gas release dynamics from fuel during thermal transients. Furthermore, the mass spectrometer instrument combines the capabilities and performances of both on-line (for release kinetic) and off-line implementations (for delayed accurate analysis of capacities containing total release gas). The paper deals with two main axes: (1) the modelling of gas sampling inlet device and its performance and (2) the first MS qualification/calibration results. The inlet device samples the gas and also adapts the pressure between MERARG sweeping line at 1.2 bar and mass spectrometer chamber at high vacuum. It is a two-stage device comprising a capillary at inlet, an intermediate vacuum chamber, a molecular leak inlet and a two-stage pumping device. Pressure drops, conductance and throughputs are estimated both for mass spectrometer operation and for exhaust gas recovery. Possible gas segregation is also estimated and device modification is proposed to attain a more accurate calibration. First experimental results obtained from a standard gas bottle show that the quantitative analysis at a few ppm level can be achieved for all isotopes of Kr and Xe, as well as masses 2 and 4 u. (authors)

  2. A review of fission gas release data within the Nea/IAEA IFPE database

    International Nuclear Information System (INIS)

    Turnbull, J.A.; Menut, P.; Sartori, E.

    2002-01-01

    The paper describes the International Fuel Performance Experimental (IFPE) database on nuclear fuel performance. The aim of the project is to provide a comprehensive and well-qualified database on Zr clad UO 2 fuel for model development and code validation in the public domain. The data encompass both normal and off-normal operation and include prototypic commercial irradiations as well as experiments performed in material testing reactors. To date, the database contains some 380 individual cases, the majority of which provide data on FGR either from in-pile pressure measurements or PIE techniques including puncturing, electron probe microanalysis (EPMA) and X-ray fluorescence (XRF) measurements. The paper outlines parameters affecting fission gas release and highlights individual datasets addressing these issues. (authors)

  3. Overview of use of natural gas on heavy duty vehicles in Brazil; Panorama da utilizacao do gas natural veicular em veiculos pesados no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Guilherme Bastos; Melo, Tadeu Cavalcante Cordeiro de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). Area de Desempenho de Produtos em Motores; Lastres, Luiz Fernando Martins [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). Gerencia de Lubrificantes e Produtos Especiais

    2004-07-01

    The use of vehicular natural gas (VNG) was initiated in Brazil in he 80's seeking the replacement of diesel in heavy vehicles due to the oil crisis. In this season PETROBRAS participated, along with other companies, in the development of conversion technologies for replacement part of the diesel by natural gas through systems known as diesel-gas. Were made works to development bank of tests of engines and field tests on some bus companies, verifying if there are technical and economic viability of such conversion. Due to factors such as small mesh distribution of natural gas in Brazil, lack of infrastructure of technical support suitable for conversions and lack of culture in the use of natural gas, the program not progressed and experience was interrupted. Other experiments were conducted in Brazil with the use of engines dedicated to natural gas (Otto cycle) developed and manufactured in the country for use in urban buses. Currently there is a scenario favorable to the return of use of natural gas in weighed vehicles by the following factors: 1) increase the mesh distribution of VNG due to the high growth of the fleet light vehicles to VNG in the country, solving part of the problems of logistics; 2) pressure from environmental agencies by values of emissions of particles and gases ever less pollutants in urban centers; 3) excess supply of natural gas in the domestic market due to new discoveries in Brazil, contracts for the import of natural gas signed with Bolivia and low demand for current industrial consumption of gas; 4) need to replace the import of diesel, which weighs in trade of the country. This paper will be presented some experiences with the technology of diesel-gas and the engine dedicated the VNG in weighed vehicles in Brazil. Also some recommendations will be made to increase and spread the use of these technologies, aiming to increase the replacement of diesel by vehicular natural gas in weighed vehicles. (author)

  4. Development of filter module for passive filtration and accident gas release confinement system for NPP

    International Nuclear Information System (INIS)

    Yelizarov, P.G.; Efanov, A.D.; Martynov, P.N.; Masalov, D.P.; Osipov, V.P.; Yagodkin, I.V.

    2005-01-01

    Full text of publication follows: One of the urgent problems of the safe NPP operation is air cleaning from radioactive aerosols and volatile iodine compounds under the accident operation conditions of NPP. A principally new passive accident gas release confinement system is used as the basis of the designs of new generation reactor power blocks under the-beyond-design-basis accident conditions with total loss of current. The basic structural component of the passive filtration system (PFS) is the filter-sorber being heated up to 300 deg. C. The filter-sorber represents a design consisting of 150 connected in parallel two-step filtering modules. The first step is intended to clean air from radioactive aerosols, the second one - to clean air from radioactive iodine and its volatile compounds. The filter-sorber is located in the upper point of the exterior protection shell. Due to natural convection, it provides confinement of r/a impurities and controlled steam-gas release from the inter-shell space into atmosphere. The basic specific design feature is the two-section design of the PFS filter module consisting of a coarse-cleaning section and a fine-cleaning section. A combination of layer-by-layer put filtering materials on the basis of glass fiber and metal fiber. The pilot PFS filter module specimen tests run in conditions modeling accident situation indicated that at a filtration rate of 0,3 cm/s the aerodynamic resistance of the module does not exceed 12 Pa, the filtration effectiveness equals 99,99 % in terms of aerosol, no less than 99,9% in terms of radioactive 131 I and no less than 99,0% in terms of organic compounds of iodine (CH 3 131 I); the dust capacity amounts to a value above 50 g/m 2 . The obtained results of tests comply with the design requirements imposed on the PFS filter-sorber module. (authors)

  5. Levonorgestrel-releasing intrauterine system for treatment of heavy menstrual bleeding in adolescents with Glanzmann's Thrombasthenia: illustrated case series.

    Science.gov (United States)

    Lu, Meiqiu; Yang, Xin

    2018-02-27

    Glanzmann's Thrombasthenia (GT) is an inherited genetic disorder caused by defects in the platelet membrane glycoproteins IIb/IIIA, and is associated with heavy menstrual bleeding (HMB). HMB is a common complication in female patients, and many adolescent girls with this disease have issues with HMB beginning at menarche. The available treatment modalities including anti-fibrinolytics, nonsteroidal anti-inflammatory drugs (NSAIDs) and hormonal therapies though are effective, their associated side effects, limited efficacy and the poor compliance is a challenge in management of HMB. Levonorgestrel-releasing intrauterine system (LNG-IUS) has been a potential alternative to overcome this challenge. The use of the LNG-IUS for the management of HMB in adolescents with GT is explored in this case series. Two adolescents diagnosed with GT and received the LNG-IUS as treatment modality for management of HMB is discussed in this case series. For patients with poor compliance to oral hormonal therapies, the use of LNG-IUS is associated with a significant reduction of menstrual blood loss along with improved quality of life. These findings support the use of LNG-IUS to control adolescent GT-related HMB.

  6. Fission gas release from ThO2 and ThO2--UO2 fuels (LWBR development program)

    International Nuclear Information System (INIS)

    Goldberg, I.; Spahr, G.L.; White, L.S.; Waldman, L.A.; Giovengo, J.F.; Pfennigwerth, P.L.; Sherman, J.

    1978-08-01

    Fission gas release data are presented from 51 fuel rods irradiated as part of the LWBR irradiations test program. The fuel rods were Zircaloy-4 clad and contained ThO 2 or ThO 2 -UO 2 fuel pellets, with UO 2 compositions ranging from 2.0 to 24.7 weight percent and fuel densities ranging from 77.8 to 98.7 percent of theoretical. Rod diameters ranged from 0.25 to 0.71 inches and fuel active lengths ranged from 3 to 84 inches. Peak linear power outputs ranged from 2 to 22 kw/ft for peak fuel burnups up to 56,000 MWD/MTM. Measured fission gas release was quite low, ranging from 0.1 to 5.2 percent. Fission gas release was higher at higher temperature and burnup and was lower at higher initial fuel density. No sensitivity to UO 2 composition was evidenced

  7. General design and main problems of a gas-heavy-water power reactor contained in a pressure vessel

    International Nuclear Information System (INIS)

    Roche, R.; Gaudez, J.C.

    1964-01-01

    In the framework of research carried out on a CO 2 -cooled power reactor moderated by heavy water, the so-called 'pressure vessel' solution involves the total integration of the core, of the primary circuit (exchanges and blowers) and of the fuel handling machine inside a single, strong, sealed vessel made of pre-stressed concrete. A vertical design has been chosen: the handling 'attic' is placed above the core, the exchanges being underneath. This solution makes it possible to standardize the type of reactor which is moderated by heavy-water or graphite and cooled by a downward stream of carbon dioxide gas; it has certain advantages and disadvantages with respect to the pressure tube solution and these are considered in detail in this report. Extrapolation presents in particular.problems due specifically to the heavy water (for example its cooling,its purification, the balancing of the pressures of the heavy water and of the gas, the assembling of the internal structures, the height of the attic, etc. (authors) [fr

  8. Overview on international experimental programmes on power ramping and fission gas release

    International Nuclear Information System (INIS)

    Knaab, H.; Lang, P.M.; Mogard, H.

    1983-01-01

    During the last years a number of internationally sponsored experimental programmes were initiated to study the LWR fuel behaviour during ramping and fission gas release at higher burnup levels. Common interest and the limited availability of experimental facilities and appropriate test fuel rods have led to valuable cooperation of many organizations throughout the nuclear community. These programmes are performed by the experimental staff from research centers with their experimental facilities. Fuel vendors and several utilities contribute by supply and irradiation of test fuel rods. The aim of this paper is to provide a synopsis of the following programmes: Studsvik Projects: Interramp, Overramp, Superramp, Demoramp I and II; Petten, High Burnup PWR Ramp Test Programme; Mol, Tribulation Programme; BNWL, High Burnup Effects Programme; Risoe Fission Gas Project; Related tasks within the OECD Halden Reactor Project. The objectives of the programme, their work scope and main results will be summarized on the basis of presently available information. An outlook to future proposed programmes will be given. (author)

  9. Overview on international experimental programmes on power ramping and fission gas release

    International Nuclear Information System (INIS)

    Knaab, H.; Lang, P.M.

    1985-01-01

    During the last few years a number of internationally sponsored experimental programmes have been initiated to study LWR fuel behaviour during ramping and fission gas release at high burnup levels. Common interest and the limited availability of experimental facilities and appropriate test fuel rods have led to valuable cooperation between many organizations throughout the nuclear community. These programmes are carried out by experienced staff from research centres using the centres' experimental facilities. Fuel vendors and several utilities contribute by supplying and irradiating the test fuel rods. The aim of this paper is to provide a synopsis of the following programmes: (a) Studsvik Projects: Interramp, Demoramp I and II, Overramp, Superramp; (b) Petten, High Burnup PWR Ramp Test Programme; (c) Mol, Tribulation Programme; (d) BNWL, High Burnup Effects Programme; (e) Riso Fission Gas Project; and (f) related tasks within the OECD Halden Reactor Project. The objectives of the programmes, their scope and the main results will be summarized. An overview of proposed future programmes will be given. (author)

  10. Manufacturing and test of a low cost polypropylene bag to reduce the radioactive gas released by a radiopharmaceutical production facility

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Jose Carlos Freitas; Lacerda, Marco Aurelio de Sousa, E-mail: jcft@cdtn.b, E-mail: masl@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (SEPRA/ CDTN/CNEN-MG) Belo Horizonte, MG (Brazil). Servico de Protecao Radiologica; Nascimento, Leonardo Tafas Constantino do; Silva, Juliana Batista da, E-mail: ltcn@cdtn.b, E-mail: silvajb@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (SECPRA/ CDTN/CNEN-MG) Belo Horizonte, MG (Brazil). Secao de Producao de Radiofarmacos

    2011-07-01

    The main objective of this work was to evaluate the efficiency of a plastic gas storage bag to reduce the radioactive gas released by the chimney of a radiopharmaceutical production facility during the 2-[{sup 18}F]fluoro-2- deoxy-D-glucose ({sup 18}FDG) synthesis. The studied facility was the Development Centre of Nuclear Technology (CDTN/CNEN) in Belo Horizonte, Brazil. The bag was manufactured utilizing foils of polypropylene of 360 x 550 x 0.16 mm and disposable components of the cassette of the synthesizer. Two synthesis of {sup 18}FDG were done using the same hot cell and synthesizer to evaluate the efficiency of the bag. The manufactured bag was put in the gas exit of the synthesizer and the activity reported by the online radiation monitoring system in the first synthesis. These results were compared to the activity released in a synthesis performed without the bag. We observed when the bag was used the amount released was about 0.2% in 270 minutes. The second synthesis was performed without the bag, about 7,1% of the input activity was released by the exhaust of the facility in the same time interval. The bag presented a very good efficiency in the reducing of the radioactive gas released by the chimney of the radiopharmaceutical production facility. (author)

  11. Manufacturing and test of a low cost polypropylene bag to reduce the radioactive gas released by a radiopharmaceutical production facility

    International Nuclear Information System (INIS)

    Tavares, Jose Carlos Freitas; Lacerda, Marco Aurelio de Sousa; Nascimento, Leonardo Tafas Constantino do; Silva, Juliana Batista da

    2011-01-01

    The main objective of this work was to evaluate the efficiency of a plastic gas storage bag to reduce the radioactive gas released by the chimney of a radiopharmaceutical production facility during the 2-[ 18 F]fluoro-2- deoxy-D-glucose ( 18 FDG) synthesis. The studied facility was the Development Centre of Nuclear Technology (CDTN/CNEN) in Belo Horizonte, Brazil. The bag was manufactured utilizing foils of polypropylene of 360 x 550 x 0.16 mm and disposable components of the cassette of the synthesizer. Two synthesis of 18 FDG were done using the same hot cell and synthesizer to evaluate the efficiency of the bag. The manufactured bag was put in the gas exit of the synthesizer and the activity reported by the online radiation monitoring system in the first synthesis. These results were compared to the activity released in a synthesis performed without the bag. We observed when the bag was used the amount released was about 0.2% in 270 minutes. The second synthesis was performed without the bag, about 7,1% of the input activity was released by the exhaust of the facility in the same time interval. The bag presented a very good efficiency in the reducing of the radioactive gas released by the chimney of the radiopharmaceutical production facility. (author)

  12. Bubble development and fission gas release during rapid heating of 18 GWd/TeU UO2

    International Nuclear Information System (INIS)

    Small, G.J.

    1985-01-01

    Small samples (approximately 50 mg) of UO 2 irradiated to 18 GWd/TeU have been heated rapidly in an out-of-pile furnace. Ramp rates were in the range 10-80 deg. C.s -1 , peak temperatures varied from 1400 deg. C to 2500 deg. C and dwell times from one to fifteen min. The specimens were sealed in small capsules which were subsequently pierced to determine the total amount of fission gas ( 85 Kr) released during each test. Changes in the size and number of gas bubbles on grain boundaries were examined using SEM, TEM, replication and fractography techniques will be employed later. In this paper are reported the first series of gas release results and some metallography. The results are compared with related experiments and some qualitative conclusions are drawn regarding the mechanisms and kinetics of transient fission gas behaviour. (author)

  13. Surfacing behavior and gas release of the physostome sprat (Sprattus sprattus) in ice-free and ice-covered waters

    KAUST Repository

    Solberg, Ingrid

    2013-10-04

    Upward-facing echosounders that provided continuous, long-term measurements were applied to address the surfacing behavior and gas release of the physostome sprat (Sprattus sprattus) throughout an entire winter in a 150-m-deep Norwegian fjord. During ice-free conditions, the sprat surfaced and released gas bubbles at night with an estimated surfacing rate of 3.5 times per fish day-1. The vertical swimming speeds during surfacing were considerably higher (~10 times) than during diel vertical migrations, especially when returning from the surface, and particularly when the fjord was not ice covered. The sprat released gas a few hours after surfacing, suggesting that the sprat gulped atmospheric air during its excursions to the surface. While the surface activity increased after the fjord became ice covered, the records of gas release decreased sharply. The under-ice fish then displayed a behavior interpreted as "searching for the surface" by repeatedly ascending toward the ice, apparently with limited success of filling the swim bladder. This interpretation was supported by lower acoustic target strength in ice-covered waters. The frequent surfacing behavior demonstrated in this study indicates that gulping of atmospheric air is an important element in the life of sprat. While at least part of the population endured overwintering in the ice-covered habitat, ice covering may constrain those physostome fishes that lack a gas-generating gland in ways that remain to be established. 2013 The Author(s).

  14. A method for simulating the release of natural gas from the rupture of high-pressure pipelines in any terrain.

    Science.gov (United States)

    Deng, Yajun; Hu, Hongbing; Yu, Bo; Sun, Dongliang; Hou, Lei; Liang, Yongtu

    2018-01-15

    The rupture of a high-pressure natural gas pipeline can pose a serious threat to human life and environment. In this research, a method has been proposed to simulate the release of natural gas from the rupture of high-pressure pipelines in any terrain. The process of gas releases from the rupture of a high-pressure pipeline is divided into three stages, namely the discharge, jet, and dispersion stages. Firstly, a discharge model is established to calculate the release rate of the orifice. Secondly, an improved jet model is proposed to obtain the parameters of the pseudo source. Thirdly, a fast-modeling method applicable to any terrain is introduced. Finally, based upon these three steps, a dispersion model, which can take any terrain into account, is established. Then, the dispersion scenarios of released gas in four different terrains are studied. Moreover, the effects of pipeline pressure, pipeline diameter, wind speed and concentration of hydrogen sulfide on the dispersion scenario in real terrain are systematically analyzed. The results provide significant guidance for risk assessment and contingency planning of a ruptured natural gas pipeline. Copyright © 2017. Published by Elsevier B.V.

  15. Code of practice for the release of hydrostatic test water from hydrostatic testing of petroleum liquid and gas pipelines

    International Nuclear Information System (INIS)

    1999-01-01

    This booklet describes a series of administrative procedures regarding the code of practice in Alberta for the release of hydrostatic test water from hydrostatic testing of petroleum liquid and gas pipelines. The topics covered include the registration process, the type and quality of water to use during the test, and the analytical methods to be used. Reporting schedule and record keeping information are also covered. Schedule 1 discusses the requirements for the release of hydrostatic test water to land, while Schedule 2 describes the requirements for the release of hydrostatic test water to receiving water. 3 tabs

  16. Detection of cold gas releases in space via low energy neutral atom imaging

    International Nuclear Information System (INIS)

    McComas, D.J.; Funsten, H.O.; Moore, K.R.; Scime, E.E.; Thomsen, M.F.

    1993-01-01

    Low energy neutral atoms (LENAs) are produced in space plasmas by charge exchange between the ambient magnetospheric plasma ions and cold neutral atoms. Under normal conditions these cold neutrals come from the terrestrial geocorona, a shroud of few-eV hydrogen atoms surrounding the Earth. As a consequence of this charge exchange, it has become possible to remotely image many regions of the magnetosphere for the first time utilizing recently developed LENA imaging technology. In addition to the natural hydrogen geocorona, conventional explosions and maneuvering thruster firings can also introduce large amounts of cold gas into the space environment. In this paper the authors examine whether such potentially clandestine activities could also be remotely observed for the first time via LENA imaging. First, they examine the fluxes of LENAs produced in the space environment from a conventional explosion. Then they review the present state of the art in the emerging field of LENA detection and imaging. Recent work has shown that LENAs can be imaged by first converting the neutrals to ions with ultra-thin (10s of angstrom) foils and then electrostatically analyzing these newly created ions to reject the large (> 10 10 cm -2 s -1 ) UV background to which the low energy detectors are sensitive. They conclude that the sensitivities for present LENA imager designs may be just adequate for detecting some man-made releases. With additional improvements in LENA detection capabilities, this technique could become an important new method for monitoring for conventional explosions, as well as other man-made neutral releases, in the space environment

  17. Comparison of life cycle greenhouse gases from natural gas pathways for medium and heavy-duty vehicles.

    Science.gov (United States)

    Tong, Fan; Jaramillo, Paulina; Azevedo, Inês M L

    2015-06-16

    The low-cost and abundant supply of shale gas in the United States has increased the interest in using natural gas for transportation. We compare the life cycle greenhouse gas (GHG) emissions from different natural gas pathways for medium and heavy-duty vehicles (MHDVs). For Class 8 tractor-trailers and refuse trucks, none of the natural gas pathways provide emissions reductions per unit of freight-distance moved compared to diesel trucks. When compared to the petroleum-based fuels currently used in these vehicles, CNG and centrally produced LNG increase emissions by 0-3% and 2-13%, respectively, for Class 8 trucks. Battery electric vehicles (BEVs) powered with natural gas-produced electricity are the only fuel-technology combination that achieves emission reductions for Class 8 transit buses (31% reduction compared to the petroleum-fueled vehicles). For non-Class 8 trucks (pick-up trucks, parcel delivery trucks, and box trucks), BEVs reduce emissions significantly (31-40%) compared to their diesel or gasoline counterparts. CNG and propane achieve relatively smaller emissions reductions (0-6% and 19%, respectively, compared to the petroleum-based fuels), while other natural gas pathways increase emissions for non-Class 8 MHDVs. While using natural gas to fuel electric vehicles could achieve large emission reductions for medium-duty trucks, the results suggest there are no great opportunities to achieve large emission reductions for Class 8 trucks through natural gas pathways with current technologies. There are strategies to reduce the carbon footprint of using natural gas for MHDVs, ranging from increasing vehicle fuel efficiency, reducing life cycle methane leakage rate, to achieving the same payloads and cargo volumes as conventional diesel trucks.

  18. Fission gas and iodine release measured in IFA-430 up to 15 GWd/t UO2 burnup

    International Nuclear Information System (INIS)

    Appelhans, A.D.; Turnbull, J.A.; White, R.J.

    1983-01-01

    The release of fission products from fuel pellets to the fuel-cladding gap is dependent on the fuel temperature, the power (fission rate) and the burnup (fuel structure). As part of the US Nuclear Regulatory Commission's Fuel Behavior Program, EG and G Idaho, Inc., is conducting fission product release studies in the Heavy Boiling Water Reactor in Halden, Norway. This paper presents a summary of the results up to December, 1982. The data cover fuel centerline temperatures ranging from 700 to 1500 0 C for average linear heat ratings of 16 to 35 kW/m. The measurements have been performed for the period between 4.2 and 14.8 GWd/t UO 2 of burnup of the Instrumented Fuel Assembly 430 (IFA-430). The measurement program has been directed toward quantifying the release of the short-lived radioactive noble gases and iodines

  19. Development and evaluation of a new prototype P&T system to determine in-heading gas release rate.

    CSIR Research Space (South Africa)

    Van Zyl, FJ

    2001-11-01

    Full Text Available In order to quantify the potential methane hazard in underground coal mines, it is necessary to determine the in-seam methane content and an expected gas release rate during production. Various methods for estimating this have been proposed, ranging...

  20. Effect of power change on fission gas release. Re-irradiation tests of spent fuel at JMTR

    International Nuclear Information System (INIS)

    Nakamura, Jinichi; Shimizu, Michio; Ishii, Tadahiko; Endo, Yasuichi; Ohwada, Isao; Nabeya, Hideaki; Uetsuka, Hiroshi

    1999-01-01

    A full length rod irradiated at Tsuruga unit 1 was refabricated to short length rods, and rod inner pressure gauges were re-instrumented to the rods. Re-irradiation tests to study the fission gas release during power change were carried out by means of BOCA/OSF-1 facility at the JMTR. In the tests, steady state operation at 40 kW/m and power cycling operations between 20 and 40 kW/m were conducted for the same high power holding time, and the rod inner pressure change during the tests was measured. The rod inner pressure increase was observed during power change, especially during power reduction. The rod inner pressure increase during a power cycling depended on the length of the high power operation just before the power cycling. The fission gas release during power reduction is estimated to be the release from fission gas bubbles on the grain boundary caused by the thermal stress in the pellet during power reduction. When steady state operation and power cycling were repeated at the power levels of 30, 35 and 40 kW/m, the power cycling accelerated the fission gas release compared with the steady state operation. (author)

  1. A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis

    Science.gov (United States)

    Ström, Petter; Petersson, Per; Rubel, Marek; Possnert, Göran

    2016-10-01

    A dedicated detector system for heavy ion elastic recoil detection analysis at the Tandem Laboratory of Uppsala University is presented. Benefits of combining a time-of-flight measurement with a segmented anode gas ionization chamber are demonstrated. The capability of ion species identification is improved with the present system, compared to that obtained when using a single solid state silicon detector for the full ion energy signal. The system enables separation of light elements, up to Neon, based on atomic number while signals from heavy elements such as molybdenum and tungsten are separated based on mass, to a sample depth on the order of 1 μm. The performance of the system is discussed and a selection of material analysis applications is given. Plasma-facing materials from fusion experiments, in particular metal mirrors, are used as a main example for the discussion. Marker experiments using nitrogen-15 or oxygen-18 are specific cases for which the described improved species separation and sensitivity are required. Resilience to radiation damage and significantly improved energy resolution for heavy elements at low energies are additional benefits of the gas ionization chamber over a solid state detector based system.

  2. Aerosol release from a hot sodium pool and behaviour in inert gas atmosphere

    International Nuclear Information System (INIS)

    Sauter, H.; Schuetz, W.

    1986-01-01

    In the KfK-NALA program, experiments were carried out on the subject of aerosol release from a contaminated sodium pool into inert gas atmosphere under various conditions. Besides the determination of retention factors for fuel and fission products, the sodium aerosol system was investigated and characterized, concerning aerosol generation (evaporation rate), particle size, mass concentration, and deposition behaviour. Pool temperatures were varied between 700 and 1000 K at different geometrical and convective conditions. Technical scale experiments with a 531-cm 2 pool surface area were performed at natural convection in a 2.2-m 3 heated vessel, as well as additional small scale experiments at forced convection and 38.5-cm 2 pool surface area. A best-fit formula is given for the specific evaporation rate into a 400 K argon atmosphere. Approximately, the very convenient relation (dm/dt) (kg/m 2 /h) = 0.1 p (mm Hg) was found. The sodium aerosol diameter lay between 0.6 μm, less than 1 sec after production, and 2.5 μm at maximum concentration. The deposition behaviour was characterized by very small quantities ( 80%) on the bottom cover of the vessel. In the model theoretic studies with the PARDISEKO code, calculations were performed of the mass concentration, particle diameter and deposition behaviour. Agreement with the experimental values could not be achieved until a modulus was introduced to allow for turbulent deposition. (author)

  3. Studies on fuels with low fission gas release. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    1997-10-01

    For more than a decade, the IAEA has organized various specialists meetings to discuss advances in nuclear fuel technology for non-water cooled reactors. In order to review progress in research and development of fuels with low fission gas release for light water reactors, fast reactors and research reactors, an IAEA Technical Committee meeting was organized in October 1996. At the invitation of the Government of the Russian Federation, the meeting was held in Moscow. Experts from seven Member States and one international organization participated. The objective of the meeting was to exchange topical information on such fuels, to evaluate their advantages and drawbacks, and to explore their commercial utilization. The present volume contains the full text of the sixteen papers presented at the meeting. The information compiled in these proceedings should be useful for engineers, scientists and managers from nuclear fuel development organizations, fuel fabrication plants, utilities and regulatory bodies who are involved in the analysis of fuel behaviour under normal and accident conditions. Refs, figs, tabs

  4. Framework for estimating toxic releases from the application of manure on agricultural soil: National release inventories for heavy metals in 2000-2014

    DEFF Research Database (Denmark)

    Leclerc, Alexandra Segolene Corinne; Laurent, Alexis

    2017-01-01

    Livestock manure is commonly applied on agricultural land for its fertilising properties. However, the presence of toxic substances in animal manure such as pathogens, antibiotics and heavy metals, can result in damages to ecosystems and human health. To date, although relevant for policy-making, e...... of uncertainties and limitations were identified. In particular, the need for harmonising sampling and analytical methods for estimating heavy metal contents in manure and generating more country-differentiated data, especially for developing countries, should be prioritised by future research studies. Using life...

  5. Experience in the development of metal uranium-base nuclear fuel for heavy-water gas-cooled reactors

    International Nuclear Information System (INIS)

    Ashikhmin, V.P.; Vorob'ev, M.A.; Gusarov, M.S.; Davidenko, A.S.; Zelenskij, V.F.; Ivanov, V.E.; Krasnorutskij, V.S.; Petel'guzov, I.A.; Stukalov, A.I.

    1978-01-01

    Investigations were carried out to solve the problem of making the development of radiation-resistant uranium fuel for power reactors including the heavy-water gas-cooled KS-150 reactor. Factors are considered that limit the lifetime of uranium fuel elements, and the ways of suppressing them are discussed. Possible reasons of the insufficient radiation resistance of uranium rod fuel element and the progress attained are analyzed. Some general problems on the fuel manufacture processes are discussed. The main results are presented on the operation of the developed fuel in research reactor loops and the commercial heavy-water KS-150 reactor. The results confirm an exceptionally high radiation resistance of fuel to burn-ups of 1.5-2%. The successful solution of a large number of problems associated with the development of metal uranium fuel provides for new possibilities of using metal uranium in power reactors

  6. Physical modelling of the dispersion of heavy gases released in an accident for the assessment of hazardous areas in built-up terrain

    International Nuclear Information System (INIS)

    Marotzke, K.

    1993-01-01

    The report on experimental results which were obtained above all within the heavy gas dispersion phase of the clouds. This phase extends up to a distance from the source distance in which the initial heavy gas concentration has decreased to about 1% by volume of the source concentration. The lower ignition limit of all gases of interest for industrial applications is above this threshold; the ignition distances of combustible gases can therefore be determined directly in the physical model. The concentration field in the complex near field of the cloud is modelled physically. The results obtained in the wind tunnel serve as input data for a numeric model; the concentrations and the dose values at points in the far field can be calculated with the model. The main section contains a detailed dimensional analysis for the two fundamentally possible emission types, i.e. spontaneous and continuous emissions. An experimental program was developed on this basis. With the program, the heavy gas dispersion under the influence of 25 different obstacle configurations was investigated. The results were represented in diagrams. With the aid of the diagrams, the lower ignition distances can be determined for combustible gases; for toxic gases, the initial conditions for the numeric far field model. (orig./KW) [de

  7. Deuterium concentration deterioration in feed synthesis gas from ammonia plant to heavy water plant (Preprint No. ED-5)

    International Nuclear Information System (INIS)

    Sah, A.K.

    1989-04-01

    Heavy Water Plant (Thal) is designed for 110 T/ Year capacity (55 T/Year each stream), with inlet deuterium concentration of feed synthesis gas at 115 ppm and depleted to 15 ppm. During first start up of plant the inlet concentration to feed synthesis gas was about 97 ppm. At that time the rich condensate recirculation was not there. To make the effective recirculation of deuterium rich condensate and minimum posssible losses some modifications were carried out in ammonia plant. Major ones are: (i)Demineralised (DM) water export for heavy water plant and urea plant which was having deuterium rich DM water connection was connected with DM water of urea plant which is not rich in deuterium, (ii)Sample cooler pump suction was connected with raw water, (iii)Ammonia plant line No.II condensate stripper was rectified during annual shut down to avoid excessive steam venting from its top and other draining, and (iv)Stripper condensate directly connected to make up water bypassing open settler to avoid evaporation and diffusion losses. With these modifications the deuterium concentration in feed synthesis gas improved to about 105 ppm. To improve it to 115 ppm, further modifications are suggested. (author). 5 figs

  8. Heavy water moderated gas-cooled reactors; Filiere eau lourde - gaz

    Energy Technology Data Exchange (ETDEWEB)

    Bailly du Bois, B; Bernard, J L; Naudet, R; Roche, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    France has based its main effort for the production of nuclear energy on natural Uranium Graphite-moderated gas-cooled reactors, and has a long term programme for fast reactors, but this country is also engaged in the development of heavy water moderated gas-cooled reactors which appear to present the best middle term prospects. The economy of these reactors, as in the case of Graphite, arises from the use of natural or very slightly enriched Uranium; heavy water can take the best advantages of this fuel cycle and moreover offers considerable development potential because of better reactor performances. A prototype plant EL 4 (70 MW) is under construction and is described in detail in another paper. The present one deals with the programme devoted to the development of this reactor type in France. Reasons for selecting this reactor type are given in the first part: advantages and difficulties are underlined. After reviewing the main technological problems and the Research and Development carried out, results already obtained and points still to be confirmed are reported. The construction of EL 4 is an important step of this programme: it will be a significant demonstration of reactor performances and will afford many experimentation opportunities. Now the design of large power reactors is to be considered. Extension and improvements of the mechanical structures used for EL 4 are under study, as well as alternative concepts. The paper gives some data for a large reactor in the present state of technology, as a result from optimization studies. Technical improvements, especially in the field of materials could lead to even more interesting performances. Some prospects are mentioned for the long run. Investment costs and fuel cycles are discussed in the last part. (authors) [French] La France, qui a base son effort principal pour la production d'energie nucleaire sur la filiere des reacteurs a uranium naturel et graphite refroidis par gaz, et qui a un programme a plus

  9. Quantitative Analysis of Kr-85 Fission Gas Release from Dry Process for the Treatment of Spent PWR Fuel

    International Nuclear Information System (INIS)

    Park, Geun Il; Cho, Kwang Hun; Lee, Dou Youn; Lee, Jung Won; Park, Jang Jin; Song, Kee Chan

    2007-01-01

    As spent UO 2 fuel oxidizes to U 3 O 8 by air oxidation, a corresponding volume expansion separate grains, releasing the grain-boundary inventory of fission gases. Fission products in spent UO 2 fuel can be distributed in three major regions : the inventory in fuel-sheath gap, the inventory on grain boundaries and the inventory in UO 2 matrix. Release characteristic of fission gases depends on its distribution amount in three regions as well as spent fuel burn-up. Oxidation experiments of spent fuel at 500 .deg. C gives the information of fission gases inventory in spent fuel, and further annealing experiments at higher temperature produces matrix inventory of fission gases on segregated grain. In previous study, fractional release characteristics of Kr- 85 during OREOX (Oxidation and REduction of Oxide fuel) treatment as principal key process for recycling spent PWR fuel via DUPIC cycle have already evaluated as a function of fuel burn-up with 27.3, 35 and 65 MWd/tU. In this paper, new release experiment results of Kr-85 using spent fuel with burn- up of 58 GWd/tU are included to evaluate the fission gas release behavior. As a point of summary in fission gases release behavior, the quantitative analysis of Kr- 85 release characteristics from various spent fuels with different burn-up during voloxidation and OREOX process were reviewed

  10. Radiation doses due to natural radon gas releases from the final disposal facility of spent fuel

    International Nuclear Information System (INIS)

    Vesterbacka, K.; Arvela, H.

    1998-03-01

    Building an underground repository for the spent nuclear fuel increases releases of natural radon gas. In the report the radon releases, the resulting doses as well as the radon concentration in the repository air are investigated. There are four optional building locations for the underground repository and three different strategies of construction. Optional sites are Olkiluoto of Eurajoki, Romuvaara of Kuhmo, Haestholmen of Loviisa and Kivetty of Aeaenekoski. The most significant radon sources in the underground repository are the rockwalls and the groundwater leaking to the repository. High groundwater radon concentrations can increase significantly radon concentration in the repository air despite the groundwater leak rate is low. The radon source strength from the rockwalls, groundwater and macadam spreaded on the floor of the repository is estimated in this report. Using these results the radon concentration in the repository is calculated for several air exchange rates. Data from petrological studies performed at the optional building sites as well as the measurement data of the Radiation and Nuclear Safety Authority has been utilized. Rough approximations were needed when estimating the radon source strength. The estimated total radon source strength varies between 1 - 600 MBq/h depending on the repository construction strategy. Repository indoor air radon concentration with no air exchange varies between 0,7 - 120 kBq/m 3 . Using the most probable estimates on radon source strength, the allowed indoor radon concentration of 400 Bq/m 3 at workplaces is achieved by using the air exchange rate of 0,5 l/h in every optional repository. Repository exhaust air and the pile of macadam increases the radon levels in the environment. The radiation dose to the critical person depends on the open volume of the repository. The annual radiation dose calculated from the most probable radon source strength at the distance of 500 metres is below 0,005 mSv at all sites

  11. Fission gas release modelling: developments arising from instrumented fuel assemblies, out-of-pile experiments and microstructural observations

    International Nuclear Information System (INIS)

    Leech, N.A.; Smith, M.R.; Pearce, J.H.; Ellis, W.E.; Beatham, N.

    1990-01-01

    This paper reviews the development of fission gas release modelling in thermal reactor fuel (both steady-state and transient) and in particular, illustrates the way in which experimental data have been, and continue to be, the main driving force behind model development. To illustrate this point various aspects of fuel performance are considered: temperature calculation, steady-state and transient fission gas release, grain boundary gas atom capacity and microstructural phenomena. The sources of experimental data discussed include end-of-life fission gas release measurements, instrumented fuel assemblies (e.g. rods with internal pressure transducers, fuel centre thermocouples), swept capsule experiments, out-of-pile annealing experiments and microstructural techniques applied during post-irradiation evaluation. In the case of the latter, the benefit of applying many observation and analysis techniques on the same fuel samples (the approach adopted at NRL Windscale) is emphasized. This illustrates a shift of emphasis in the modelling field from the development of large, complex thermo-mechanical computer codes to the assessment of key experimental data in order to develop and evaluate sub-models which correctly predict the observed behaviour. (author)

  12. Fission gas release and swelling in the fuel pins M1-3 and F9-3: Risoe Fission Gas Project

    Energy Technology Data Exchange (ETDEWEB)

    Walker, C T; Ray, I L.F.; Coquerelle, M; Blank, H

    1982-01-01

    This report presents results for the microscopic swelling local swelling and local gas release in the pin sections M1-3-11 and F9-3-44. The local gas release was derived from the concentration of retained xenon which was measured with the electron microprobe. In addition to xenon, the radial distributions of caesium and neodymium were also determined by EMPA. Caesium is assumed to contribute to microscopic swelling because it results mainly from the decay of /sup 133/Xe, /sup 135/Xe and /sup 137/Xe and, therefore, is trapped together with xenon in bubbles and pores. Neodymium, on the other hand, is soluble in UO/sub 2/ and does not migrate under the influence of the temperature gradients that exist during irradiation. Therefore, the radial distribution of this fission product is an indelible imprint of the burn-up from which the average flux depression can be deduced. 1 ref., 15 figs., 3 tabs.

  13. Release kinetics and mechanisms of trace heavy metals from cement based material; Cinetiques et mecanismes de relargage des metaux lourds presents en traces dans les matrices cimentaires

    Energy Technology Data Exchange (ETDEWEB)

    Moudilou, E.

    2002-12-15

    Chemical species contained in a solid matrix may be transferred to the environment through water leaching. Previous studies of trace metals released from building materials (particularly cement-based ones) highlight an important analytical difficulty. The aim of this study is to determine the kinetics and the mechanisms involved in the release of trace heavy metals (Cr, Cu, Ni, Pb, V and Zn) from industrial cement pastes (usually ranging from 20 to 300 ppm). The development of a dynamic leaching system, named CTG-LEACHCRETE, (used at pH=5, 20 C) which permits the evaluation of the kinetics of trace heavy metals is presented in the first part. Also, innovative solid analysis techniques (ICP-MS-Laser Ablation, local and Grazing Incidence X-rays Diffraction (GIXD) technique) were used to characterise the cement-degraded layers formed during leaching experiments. These techniques enable to monitor the mineralogical evolution and the distribution of trace metals in these areas. The confrontation of these two approaches, kinetic and solid analysis, coupled with a thorough investigation of previously developed models, lead to proposals concerning the mechanisms of release of the trace heavy metals studied. In all the cement pastes studied (CPA-CEM I, CPJ-CEM II/A and CLC-CEM V/A), chromium is trapped in ettringite by substitution SO{sub 4}{sup 2-}(U)CrO{sub 4}{sup 2-} and its release is then controlled by the dissolution of this hydrate. The behaviour of copper, nickel and zinc in degraded areas and in leachates, are correlated to the silicon of the hydrated calcium silicate (CSH), which imply that they are localised there. Lead, was never detected in the leachates. But it is also correlated to the silicon in the degraded layers. (author)

  14. Secondary ions produced from condensed rare gas targets under highly charged MeV/amu heavy ion bombardment

    International Nuclear Information System (INIS)

    Tawara, H.; Tonuma, T.; Kumagai, H.; Matsuo, T.

    1994-01-01

    Secondary ions produced from condensed rare gas targets are observed under MeV/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that very few doubly charged or practically no triply/higher charged ions have been observed, in sharp contrast to that of some condensed molecular targets. (orig.)

  15. Fretting fatigue cracking of a center guide bolt supporting the combustion chamber in a heavy-duty gas turbine engine

    Energy Technology Data Exchange (ETDEWEB)

    Neidel, Andreas; Fischer, Boromir; Gaedicke, Tobias [Siemens AG, Energy Sector, Gasturbinenwerk Berlin (Germany). Werkstoffprueflabor

    2018-04-01

    The slotted center guide bolt of the center guide feature of the lower part of the outer shell of an annular combustion chamber was found fractured in a heavy-duty gas turbine engine used for power generation, after approximately 5.500 operating hours. The incident was a one-off event and not a recurring incident. No similar events were reported from the fleet; hence the failure was not considered a field issue. The metallurgical root cause investigation that was ordered to determine the failure mechanism revealed that the incident center guide bolt failed by fretting fatigue cracking, a high cycle fatigue (HCF) phenomenon.

  16. Development of a novel heavy element chemistry apparatus using the RIKEN gas-field recoil separator as a pre-separator

    International Nuclear Information System (INIS)

    Haba, H.; Morita, K.; Enomoto, S.; Morimoto, K.; Kaji, D.; Nagame, Yuichiro

    2004-01-01

    A new system was developed, that supplied the super-heavy element separated physically as the former steps to the chemical analysis devices such as a gas or liquid chromatographs. The gas jet transportation device was newly set up on the edge of existing accelerator research facilities in the Institute of Physical and Chemical Research linac building (GARIS). To conduct the chemical separation experiment of a super-heavy element of 112 in future a radioactive isotope of mercury of light homology elements was manufactured with a gas jet uniting type online multi-tracer manufacturing device. The adsorption chromatograph experiment to the gold was performed using this system. (H. Katsuta)

  17. Release to the Gas Phase of Inorganic Elements during Wood Combustion. Part 2: Influence of Fuel Composition

    DEFF Research Database (Denmark)

    van Lith, Simone Cornelia; Jensen, Peter Arendt; Frandsen, Flemming

    2008-01-01

    temperatures in the range of 500–1150 °C in a laboratory-scale tube reactor and by performing mass balance calculations based on the weight measurements and chemical analyses of the wood fuels and the residual ash samples. Four wood fuels with different ash contents and inorganic compositions were investigated...... of the alkali metals K and Na was, however, strongly dependent on both the temperature and the fuel composition under the investigated conditions. The release of the heavy metals Zn and Pb started around 500 °C and increased sharply to more than 85% at 850 °C in the case of spruce, beech, and bark...

  18. The diversity of methoxyphenols released by pyrolysis-gas chromatography as predictor of soil carbon storage.

    Science.gov (United States)

    Jiménez-González, Marco A; Álvarez, Ana M; Carral, Pilar; González-Vila, Francisco J; Almendros, Gonzalo

    2017-07-28

    The variable extent to which environmental factors are involved in soil carbon storage is currently a subject of controversy. In fact, justifying why some soils accumulate more organic matter than others is not trivial. Some abiotic factors such as organo-mineral associations have classically been invoked as the main drivers for soil C stabilization. However, in this research indirect evidences based on correlations between soil C storage and compositional descriptors of the soil organic matter are presented. It is assumed that the intrinsic structure of soil organic matter should have a bearing in the soil carbon storage. This is examined here by focusing on the methoxyphenols released by direct pyrolysis from a wide variety of topsoil samples from continental Mediterranean ecosystems from Spain with different properties and carbon content. Methoxyphenols are typical signature compounds presumptively informing on the occurrence and degree of alteration of lignin in soils. The methoxyphenol assemblages (12 major guaiacyl- and syringyl-type compounds) were analyzed by pyrolysis-gas chromatography-mass spectrometry. The Shannon-Wiener diversity index was chosen to describe the complexity of this phenolic signature. A series of exploratory statistical analyses (simple regression, partial least squares regression, multidimensional scaling) were applied to analyze the relationships existing between chemical and spectroscopic characteristics and the carbon content in the soils. These treatments coincided in pointing out that significant correlations exist between the progressive molecular diversity of the methoxyphenol assemblages and the concentration of organic carbon stored in the corresponding soils. This potential of the diversity in the phenolic signature as a surrogate index of the carbon storage in soils is tentatively interpreted as the accumulation of plant macromolecules altered into microbially reworked structures not readily recognized by soil enzymes. From

  19. Prediction of the UO/sub 2/ fission gas release data of Bellamy and Rich using a model recently developed by Combustion Engineering

    International Nuclear Information System (INIS)

    Freeburn, H.R.; Pati, S.R.

    1983-01-01

    The trend in the light water reactor industry to higher discharge burnups of UO/sub 2/ fuel rods has initiated the modification of existing fuel rod models to better account for high burnup effects. The degree to which fission gas release from UO/sub 2/ fuel is enhanced at higher burnup is being addressed in the process. Fission gas release modeling should include the separation of the individual effects of thermal diffusion and any burnup enhancement on the release. Although some modelers have interpreted the Bellamy and Rich data on fission gas release from UO/sub 2/ fuel in this fashion, they have assumed that below about 1250 0 C the gas release is not temperature-dependent, and this has led them to predict a very strong burnup enhancement of gas release above 20 MWd/kgU. More recent data, however, suggest that an appreciable amount of fission gas is released by a thermal diffusion mechanism at even lower temperatures and will add to the fission gas released due to the temperature-independent mechanisms of knockout and recoil

  20. Pore network modelling of heavy oil depressurization : a parametric study of factors affecting critical gas saturation and three-phase relative permeabilities

    Energy Technology Data Exchange (ETDEWEB)

    Bondino, I.; McDougall, S.D. [Heriot-Watt Univ., Edinburgh, Scotland (United Kingdom); Hamon, G. [TotalFina Elf Exploration and Production (France)

    2002-07-01

    A review of how the bubble nucleation process affects the efficiency of heavy oil recovery was presented along with a discussion regarding a pore-scale simulator technique to depressurize heavy oil systems. A light oil depressurization simulation is also presented in which a straightforward instantaneous nucleation (IN) model and a more intricate progressive nucleation (PN) model have been used. Simulation results are compared to those derived from the heavy oil systems. The nucleation of bubbles, their growth by solute diffusion and expansion, plus the final stages of coalescence migration and production are the main steps in the depressurization process which were accounted for in a 3-phase simulator. The model can also determine the impact of bubble density and gas-oil diffusion coefficient on critical gas saturation and 3-phase relative permeability. The difference in results for light and heavy oils was also highlighted. In the first scenario, the evolution of gas was characterized by embryonic bubbles that are quickly and randomly nucleated once bubble-point pressure is reached. A stochastic algorithm was developed for PN from experimental observations. IN and PN observations were not necessarily contradictory. It was determined that the high interfacial tension of heavy oils leads to a more compact, capillary-dominated pattern of gas evolution compared to light oils, resulting in improved recoveries for heavy oil systems. 23 refs., 6 tabs., 23 figs.

  1. Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Minato, Kazuo [Japan Atomic Energy Research Institute (Japan); Sawa, Kazuhiro [Japan Atomic Energy Research Institute (Japan); Koya, Toshio [Japan Atomic Energy Research Institute (Japan); Tomita, Takeshi [Japan Atomic Energy Research Institute (Japan); Ishikawa, Akiyoshi [Japan Atomic Energy Research Institute (Japan); Baldwin, Charles A; Gabbard, William Alexander [Oak Ridge National Laboratory (United States); Malone, Charlie M [Oak Ridge National Laboratory (United States)

    2000-07-15

    Postirradiation heating tests of TRISO-coated UO{sub 2} particles at 1700 and 1800degC were performed to understand fission product release behavior at accident temperatures. The inventory measurements of the individual particles were carried out before and after the heating tests with gamma-ray spectrometry to study the behavior of the individual particles. The time-dependent release behavior of {sup 85}Kr, {sup 110m}Ag, {sup 134}Cs, {sup 137}Cs, and {sup 154}Eu were obtained with on-line measurements of fission gas release and intermittent measurements of metallic fission product release during the heating tests. The inventory measurements of the individual particles revealed that fission product release behavior of the individual particles was not uniform, and large particle-to-particle variations in the release behavior of {sup 110m}Ag, {sup 134}Cs, {sup 137}Cs, and {sup 154}Eu were found. X-ray microradiography and ceramography showed that the variations could not be explained by only the presence or absence of cracks in the SiC coating layer. The SiC degradation may have been related to the variations.

  2. Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    Minato, Kazuo; Sawa, Kazuhiro; Koya, Toshio; Tomita, Takeshi; Ishikawa, Akiyoshi; Baldwin, Charles A.; Gabbard, William Alexander; Malone, Charlie M.

    2000-01-01

    Postirradiation heating tests of TRISO-coated UO 2 particles at 1700 and 1800degC were performed to understand fission product release behavior at accident temperatures. The inventory measurements of the individual particles were carried out before and after the heating tests with gamma-ray spectrometry to study the behavior of the individual particles. The time-dependent release behavior of 85 Kr, 110m Ag, 134 Cs, 137 Cs, and 154 Eu were obtained with on-line measurements of fission gas release and intermittent measurements of metallic fission product release during the heating tests. The inventory measurements of the individual particles revealed that fission product release behavior of the individual particles was not uniform, and large particle-to-particle variations in the release behavior of 110m Ag, 134 Cs, 137 Cs, and 154 Eu were found. X-ray microradiography and ceramography showed that the variations could not be explained by only the presence or absence of cracks in the SiC coating layer. The SiC degradation may have been related to the variations

  3. Integrated biomass gasification using the waste heat from hot slags: Control of syngas and polluting gas releases

    International Nuclear Information System (INIS)

    Sun, Yongqi; Seetharaman, Seshadri; Liu, Qianyi; Zhang, Zuotai; Liu, Lili; Wang, Xidong

    2016-01-01

    In this study, the thermodynamics of a novel strategy, i.e., biomass/CO 2 gasification integrated with heat recovery from hot slags in the steel industry, were systemically investigated. Both the target syngas yield and the polluting gas release were considered where the effect of gasifying conditions including temperature, pressure and CO 2 reacted was analyzed and then the roles of hot slags were further clarified. The results indicated that there existed an optimum temperature for the maximization of H 2 production. Compared to blast furnace slags, steel slags remarkably increased the CO yield at 600–1400 °C due to the existence of iron oxides and decreased the S-containing gas releases at 400–700 °C, indicating potential desulfurizing ability. The identification of biomass/CO 2 gasification thermodynamics in presence of slags could thus provide important clues not only for the deep understanding of biomass gasification but also for the industrial application of this emerging strategy from the viewpoint of syngas optimization and pollution control. - Highlights: • Biomass/CO 2 gasification was integrated with the heat recovery from hot slags. • Both syngas yield and polluting gas release during gasification were determined. • There existed an optimum temperature for the maximization of H 2 production. • Steel slags increased CO yield at 600–1400 °C due to the existence of iron oxides. • Steel slags remarkably decreased the releases of S-containing gas at 400–700 °C.

  4. Detection of low-level environmental exposure rates due to noble gas releases from the Muehleberg nuclear power plant

    International Nuclear Information System (INIS)

    Czarnecki, J.; Volkle, H.; Pretre, S.

    1980-01-01

    The increase of radiation doses in the vicinity of the Swiss Nuclear Power Stations due to airborne releases is generally expected to be below one mrem/year (about one percent of the natural radiation dose). To prove this expected rate, long term measurements with pressure ionization chambers in the vicinity of the Muhleberg plant (BWR) were conducted. Two of these chambers were installed at places where the greatest dose rates from the noble gas plumes were expected in the two prevailing wind directions. The local dose rates were continuously registered on magnetic tape to allow minicomputer evaluation. After the fuel change in the summer of 1976 the noble gas releases from Muhleberg dropped considerably. From that time the noble gas releases consisted of a very low continuous component and some rare short-time spike compoments resulting from turbine and reactor trips. The dose due to the low continuous component was determined by correlating the dose rates at the measuring points with the release measure--ments at the stack and with weather conditions, and by subtracting the natural background. The short noble gas spikes lasted from minutes to some hours and caused small dose rate increases which were easily measured with the ionization chambers, and usually amounted to doses of some microroentgens. By further correlating these dose peaks with wind direction and stack emission measurements, determination of short time atmospheric dilution factors for existing weather situations became possible. By this process, the very low annual environmental doses in the range of 1 mrem per year were determined. (author)

  5. Liberation play : technology and prices help release shale gas from unconventional status

    International Nuclear Information System (INIS)

    Roche, P.

    2006-01-01

    Shale gas production is set to increase in Canada. The British Columbia (BC) Oil and Gas Commission has approved more than 20 blocks of potential shale lands as experimental scheme areas targeting Cretaceous-age and Devonian-age shales. The BC government is currently working on a royalty scheme to benefit shale gas producers by allowing them to defer the bulk of the royalty collection until projects have reached a certain economic payout point. Interest in unconventional gas has spawned activity in previously unexplored areas of BC. Coals and shales are currently being evaluated near the community of Hudson's Hope, which has an estimated 1.8 tcf of shale gas. Canadian Spirit Resources Inc., who have leased the land, are now focusing on optimizing production processes to improve the economics of shale gas recovery. In Saskatchewan, shale gas exploration is occurring in the central region of the province, far from existing oil and gas production. PanTerra Resources Corp. has recently drilled 16 wells on its Foam Lake project, and detailed core and log analyses are being conducted to improve the understanding of the lithology and rock fabric and allow the company to design completion and stimulation programs. Stealth Ventures Ltd. is concentrating on developing the tight, biogenic Colorado Shale, which extends from Manitoba to the foothills of Alberta. Because of the shallow depths, the initial drilling costs are lower for biogenic gas than for thermogenic gas. Success will depend on the right drilling and completion methods. Junior explorers are also exploring for shale gas in an area straddling the St. Lawrence River between Quebec City and Montreal. Several large companies are examining the economic potential of shale gas production throughout North America. It was concluded that oil and gas operators are becoming more confident that domestic shale gas resources will be cheaper in future than imported liquefied natural gas (LNG), which requires special ships

  6. Spatial and Temporal Variability in Biogenic Gas Accumulation and Release in The Greater Everglades at Multiple Scales of Measurement

    Science.gov (United States)

    McClellan, M. D.; Cornett, C.; Schaffer, L.; Comas, X.

    2017-12-01

    Wetlands play a critical role in the carbon (C) cycle by producing and releasing significant amounts of greenhouse biogenic gasses (CO2, CH4) into the atmosphere. Wetlands in tropical and subtropical climates (such as the Florida Everglades) have become of great interest in the past two decades as they account for more than 20% of the global peatland C stock and are located in climates that favor year-round C emissions. Despite the increase in research involving C emission from these types of wetlands, the spatial and temporal variability involving C production, accumulation and release is still highly uncertain, and is the focus of this research at multiple scales of measurement (i.e. lab, field and landscape). Spatial variability in biogenic gas content, build up and release, at both the lab and field scales, was estimated using a series of ground penetrating radar (GPR) surveys constrained with gas traps fitted with time-lapse cameras. Variability in gas content was estimated at the sub-meter scale (lab scale) within two extracted monoliths from different wetland ecosystems at the Disney wilderness Preserve (DWP) and the Blue Cypress Preserve (BCP) using high frequency GPR (1.2 GHz) transects across the monoliths. At the field scale (> 10m) changes in biogenic gas content were estimated using 160 MHz GPR surveys collected within 4 different emergent wetlands at the DWP. Additionally, biogenic gas content from the extracted monoliths was used to developed a landscape comparison of C accumulation and emissions for each different wetland ecosystem. Changes in gas content over time were estimated at the lab scale at high temporal resolution (i.e. sub-hourly) in monoliths from the BCP and Water Conservation Area 1-A. An autonomous rail system was constructed to estimate biogenic gas content variability within the wetland soil matrix using a series of continuous, uninterrupted 1.2 GHz GPR transects along the samples. Measurements were again constrained with an array

  7. ANS-5.4 fission gas release model. I. Noble gases at high temperature

    International Nuclear Information System (INIS)

    Noble, L.D.

    1979-01-01

    A correlation to describe the release of volatile radioactive fission products has been developed by the ANS Working Group (ANS 5.4) on Fuel Plenum Activity. The model for release at higher temperatures is identical in form to conventional diffusion equations, but the effective diffusion coefficient incorporates an explicit dependence upon exposure. Because applicable radioactive release data is limited, parameters in the model were determined from stable fission measurements, and calculated or measured fuel temperatures. Although the model predicts high release, particularly at higher exposures, values for many cases of interest are considerably less than the 100% assumed in some accident analyses: providing potential for removal of unnecessary conservations

  8. Estimating release of polycyclic aromatic hydrocarbons from coal-tar contaminated soil at manufactured gas plant sites. Final report

    International Nuclear Information System (INIS)

    Lee, L.S.

    1998-04-01

    One of EPRI's goals regarding the environmental behavior of organic substances consists of developing information and predictive tools to estimate the release potential of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils at manufactured gas (MGP) plant sites. A proper assessment of the distribution of contaminants under equilibrium conditions and the potential for mass-transfer constraints is essential in evaluating the environmental risks of contaminants in the subsurface at MGP sites and for selecting remediation options. The results of this research provide insights into estimating maximum release concentrations of PAHs from MGP soils that have been contaminated by direct contact with the tar or through years of contact with contaminated groundwater. Attention is also given to evaluating the use of water-miscible cosolvents for estimating aqueous phase concentrations, and assessing the role of mass-transfer constraints in the release of PAHs from MGP site soils

  9. Results of Large-Scale Testing on Effects of Anti-Foam Agent on Gas Retention and Release

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Charles W.; Guzman-Leong, Consuelo E.; Arm, Stuart T.; Butcher, Mark G.; Golovich, Elizabeth C.; Jagoda, Lynette K.; Park, Walter R.; Slaugh, Ryan W.; Su, Yin-Fong; Wend, Christopher F.; Mahoney, Lenna A.; Alzheimer, James M.; Bailey, Jeffrey A.; Cooley, Scott K.; Hurley, David E.; Johnson, Christian D.; Reid, Larry D.; Smith, Harry D.; Wells, Beric E.; Yokuda, Satoru T.

    2008-01-03

    The U.S. Department of Energy (DOE) Office of River Protection’s Waste Treatment Plant (WTP) will process and treat radioactive waste that is stored in tanks at the Hanford Site. The waste treatment process in the pretreatment facility will mix both Newtonian and non-Newtonian slurries in large process tanks. Process vessels mixing non-Newtonian slurries will use pulse jet mixers (PJMs), air sparging, and recirculation pumps. An anti-foam agent (AFA) will be added to the process streams to prevent surface foaming, but may also increase gas holdup and retention within the slurry. The work described in this report addresses gas retention and release in simulants with AFA through testing and analytical studies. Gas holdup and release tests were conducted in a 1/4-scale replica of the lag storage vessel operated in the Pacific Northwest National Laboratory (PNNL) Applied Process Engineering Laboratory using a kaolin/bentonite clay and AZ-101 HLW chemical simulant with non-Newtonian rheological properties representative of actual waste slurries. Additional tests were performed in a small-scale mixing vessel in the PNNL Physical Sciences Building using liquids and slurries representing major components of typical WTP waste streams. Analytical studies were directed at discovering how the effect of AFA might depend on gas composition and predicting the effect of AFA on gas retention and release in the full-scale plant, including the effects of mass transfer to the sparge air. The work at PNNL was part of a larger program that included tests conducted at Savannah River National Laboratory (SRNL) that is being reported separately. SRNL conducted gas holdup tests in a small-scale mixing vessel using the AZ-101 high-level waste (HLW) chemical simulant to investigate the effects of different AFAs, their components, and of adding noble metals. Full-scale, single-sparger mass transfer tests were also conducted at SRNL in water and AZ-101 HLW simulant to provide data for PNNL

  10. Simultaneous valorization and biocatalytic upgrading of heavy vacuum gas oil by the biosurfactant-producing Pseudomonas aeruginosa AK6U.

    Science.gov (United States)

    Ismail, Wael Ahmed; Mohamed, Magdy El-Said; Awadh, Maysoon N; Obuekwe, Christian; El Nayal, Ashraf M

    2017-11-01

    Heavy vacuum gas oil (HVGO) is a complex and viscous hydrocarbon stream that is produced as the bottom side product from the vacuum distillation units in petroleum refineries. HVGO is conventionally treated with thermochemical process, which is costly and environmentally polluting. Here, we investigate two petroleum biotechnology applications, namely valorization and bioupgrading, as green approaches for valorization and upgrading of HVGO. The Pseudomonas aeruginosa AK6U strain grew on 20% v/v of HVGO as a sole carbon and sulfur source. It produced rhamnolipid biosurfactants in a growth-associated mode with a maximum crude biosurfactants yield of 10.1 g l -1 , which reduced the surface tension of the cell-free culture supernatant to 30.6 mN m -1 within 1 week of incubation. The rarely occurring dirhamnolipid Rha-Rha-C 12 -C 12 dominated the congeners' profile of the biosurfactants produced from HVGO. Heavy vacuum gas oil was recovered from the cultures and abiotic controls and the maltene fraction was extracted for further analysis. Fractional distillation (SimDist) of the biotreated maltene fraction showed a relative decrease in the high-boiling heavy fuel fraction (BP 426-565 °C) concomitant with increase in the lighter distillate diesel fraction (BP 315-426 °C). Analysis of the maltene fraction revealed compositional changes. The number-average (Mn) and weight-average (Mw) molecular weights, as well as the absolute number of hydrocarbons and sulfur heterocycles were higher in the biotreated maltene fraction of HVGO. These findings suggest that HVGO can be potentially exploited as a carbon-rich substrate for production of the high-value biosurfactants by P. aeruginosa AK6U and to concomitantly improve/upgrade its chemical composition. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  11. Method for optical 15N analysis of small amounts of nitrogen gas released from an automatic nitrogen analyzer

    International Nuclear Information System (INIS)

    Arima, Yasuhiro

    1981-01-01

    A method of optical 15 N analysis is proposed for application to small amounts of nitrogen gas released from an automatic nitrogen analyzer (model ANA-1300, Carlo Erba, Milano) subjected to certain set modifications. The ANA-1300 was combined with a vacuum line attached by a molecular sieve 13X column. The nitrogen gas released from the ANA-1300 was introduced with a carrier gas of helium into the molecular sieve column which was pre-evacuated at 10 -4 Torr and cooled with outer liquid nitrogen. After removal of the helium by evacuation, the nitrogen gas fixed on the molecular sieve was released by warming the column, and then, it was sealed into pre-evacuated pyrex glass tubes at 4.5 - 5.0 Torr. In the preparation of discharge tubes, contamination of unlabelled nitrogen occurred from the carrier gas of standard grade helium, and the relative lowering of the 15 N value by it was estimated to be less than 1% when over 700 μg nitrogen was charged on the ANA-1300; when 200 μg nitrogen was charged, it was about 3.5%. However, the effect of the contamination could be corrected for by knowing the amount of contaminant nitrogen. In the analysis of plant materials by the proposed method, the coefficient of variation was less than 2%, and no significant difference was observed between results given by the present method and by the ordinary method in which samples were directly pyrolyzed in the discharge tubes by the Dumas method. The present method revealed about 1.5 μg of cross-contaminated nitrogen and was applicable to more than 200 μg of sample nitrogen. (author)

  12. Comparison of the ENIGMA code with experimental data on thermal performance, stable fission gas and iodine release at high burnup

    Energy Technology Data Exchange (ETDEWEB)

    Killeen, J C [Nuclear Electric plc, Barnwood (United Kingdom)

    1997-08-01

    The predictions of the ENIGMA code have been compared with data from high burn-up fuel experiments from the Halden and RISO reactors. The experiments modelled were IFA-504 and IFA-558 from Halden and the test II-5 from the RISO power burnup test series. The code has well modelled the fuel thermal performance and has provided a good measure of iodine release from pre-interlinked fuel. After interlinkage the iodine predictions remain a good fit for one experiment, but there is significant overprediction for a second experiment (IFA-558). Stable fission gas release is also well modelled and the predictions are within the expected uncertainly band throughout the burn-up range. This report presents code predictions for stable fission gas release to 40GWd/tU, iodine release measurements to 50GWd/tU and thermal performance (fuel centre temperature) to 55GWd/tU. Fuel ratings of up to 38kW/m were modelled at the high burn-up levels. The code is shown to accurately or conservatively predict all these parameters. (author). 1 ref., 6 figs.

  13. Use of Flue Gas Desulfurization (FGD) Gypsum as a Heavy Metal Stabilizer in Contaminated Soils

    Science.gov (United States)

    Flue Gas Desulfurization (FGD) gypsum is a synthetic by-product generated from the flue gas desulfurization process in coal power plants. It has several beneficial applications such as an ingredient in cement production, wallboard production and in agricultural practice as a soil...

  14. Gas release during salt-well pumping: Model predictions and laboratory validation studies for soluble and insoluble gases

    International Nuclear Information System (INIS)

    Peurrung, L.M.; Caley, S.M.; Gauglitz, P.A.

    1997-08-01

    The Hanford Site has 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. Of these, 67 are known or suspected to have leaked liquid from the tanks into the surrounding soil. Salt-well pumping, or interim stabilization, is a well-established operation for removing drainable interstitial liquid from SSTs. The overall objective of this ongoing study is to develop a quantitative understanding of the release rates and cumulative releases of flammable gases from SSTs as a result of salt-well pumping. The current study is an extension of the previous work reported by Peurrung et al. (1996). The first objective of this current study was to conduct laboratory experiments to quantify the release of soluble and insoluble gases. The second was to determine experimentally the role of characteristic waste heterogeneities on the gas release rates. The third objective was to evaluate and validate the computer model STOMP (Subsurface Transport over Multiple Phases) used by Peurrung et al. (1996) to predict the release of both soluble (typically ammonia) and insoluble gases (typically hydrogen) during and after salt-well pumping. The fourth and final objective of the current study was to predict the gas release behavior for a range of typical tank conditions and actual tank geometry. In these models, the authors seek to include all the pertinent salt-well pumping operational parameters and a realistic range of physical properties of the SST wastes. For predicting actual tank behavior, two-dimensional (2-D) simulations were performed with a representative 2-D tank geometry

  15. Determination of fission gas release of spent nuclear fuel in puncturing test and in leaching experiments under anoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    González-Robles, E., E-mail: ernesto.gonzalez-robles@kit.edu [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe (Germany); Metz, V. [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe (Germany); Wegen, D.H. [European Commission, Joint Research Centre, Institute for Transuranium Elements (JRC-ITU), P.O. Box 2340, 76125, Karlsruhe (Germany); Herm, M. [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe (Germany); Papaioannou, D. [European Commission, Joint Research Centre, Institute for Transuranium Elements (JRC-ITU), P.O. Box 2340, 76125, Karlsruhe (Germany); Bohnert, E. [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe (Germany); Gretter, R. [European Commission, Joint Research Centre, Institute for Transuranium Elements (JRC-ITU), P.O. Box 2340, 76125, Karlsruhe (Germany); Müller, N. [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe (Germany); Nasyrow, R.; Weerd, W. de; Wiss, T. [European Commission, Joint Research Centre, Institute for Transuranium Elements (JRC-ITU), P.O. Box 2340, 76125, Karlsruhe (Germany); Kienzler, B. [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe (Germany)

    2016-10-15

    During reactor operation the fission gases Kr and Xe are formed within the UO{sub 2} matrix of nuclear fuel. Their quantification is important to evaluate their impact on critical parameters regarding the fuel behaviour during irradiation and (long-term) interim storage, such as internal pressure of the fuel rod and fuel swelling. Moreover the content of Kr and Xe in the plenum of a fuel rod and their content in the UO{sub 2} fuel itself are widely used as indicators for the release properties of {sup 129}I, {sup 137}Cs, and other safety relevant radionuclides with respect to final disposal of spent nuclear fuel. The present study deals with the fission gas release from spent nuclear fuel exposed to simulated groundwater in comparison with the fission gas previously released to the fuel rod plenum during irradiation in reactor. In a unique approach we determined both the Kr and Xe inventories in the plenum by means of a puncturing test and in leaching experiments with a cladded fuel pellet and fuel fragments in bicarbonate water under 3.2 bar H{sub 2} overpressure. The fractional inventory of the fission gases released during irradiation into the plenum was (8.3 ± 0.9) %. The fraction of inventory of fission gases released during the leaching experiments was (17 ± 2) % after 333 days of leaching of the cladded pellet and (25 ± 2) % after 447 days of leaching of the fuel fragments, respectively. The relatively high release of fission gases in the experiment with fuel fragments was caused by the increased accessibility of water to the Kr and Xe occluded in the fuel.

  16. Hydrotreating and hydrocracking of Athabasca bitumen derived heavy gas oils using NiMo catalyst supported on titania modified alumina

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Bakhshi, N.N.; Dalai, A.K.; Adjaye, J. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering, Catalysis and Chemical Reaction Engineering Laboratories]|[Syncrude Canada Ltd., Edmonton, AB (Canada)

    2006-07-01

    Different NiMo catalysts supported on titania modified Al{sub 2}O{sub 3} were synthesized and characterized in an effort to study the hydrodenitrigenation (HDN) and hydrodesulfurization (HDS) of different gas oils derived from Athabasca bitumen. The Al{sub x}O{sub 3} supports were modified by incorporating up to 9 wt per cent titanium (Ti). All modified supports as well as fresh and spent catalysts were characterized by BET surface area, pore volume and pore diameter, XRD, TPR, TPD and SEM. A trickle-bed reactor using 3 different gas oils from the Athabasca bitumen was used to test the initial activity of these catalysts. The 3 oils were light gas oil (LGO), heavy gas oil (HGO) and blended gas oil having 50 per cent LGO and 50 per cent HGO. The study showed that nitrogen conversion increased for all the gas oils when Ti was incorporated into the alumina. With an increase in Ti concentrations from 0 to 6 wt per cent, nitrogen conversion increased from 57-69.5 wt per cent, 75-80.2 wt per cent, 83-91.5 wt per cent and for LGO, HGO and blended, respectively. Nearly 86 wt per cent sulphur conversion was obtained for all Ti concentrations for LGO, while HGO and blended sulphur conversions were in the range of 96-97 wt per cent. Detailed hydrotreating and hydrocracking of HGO was then performed using the 6 wt per cent Ti modified catalyst because it achieved the maximum nitrogen conversion. This paper also presented the temperature, pressure and liquid hourly space velocity for this catalyst along with the maximum nitrogen and sulphur conversions. Results were compared with those of commercial catalysts. tabs., figs.

  17. Linking Volcanism and Gas Release from the North East Atlantic Volcanic Province to the PETM: Challenges and Updates

    Science.gov (United States)

    Svensen, H.; Jones, M. T.; Jerram, D. A.; Planke, S.; Kjoberg, S.; Schmid, D. W.; Iyer, K.; Tegner, C.

    2016-12-01

    The main phase of the development of the North East Atlantic Volcanic Province took place about 56 Ma and coincides with the Paleocene Eocene Thermal Maximum (PETM). The volcanic activity was characterized by voluminous flood basalts, large plutonic complexes, sub-marine eruptions, widespread tephra deposition, and emplacement of sills and dikes along the continental margins of Norway, Greenland, Ireland, and the UK. Here we review the style and tempo of volcanism during this important period of Earth's history and discuss the sources and volumes of the carbon gases emitted to the ocean and atmosphere. Moreover, we present new data and models from 1) West Greenland showing the impact on sill intrusions on gas generation from heated Cretaceous mudstones, 2) a 3D seismic survey of gas release structures offshore Norway, and 3) Paleocene-Eocene tephra layers from Svalbard and Denmark. Gas migrated out of the contact aureoles by either explosive venting or by slower seepage towards the seafloor as demonstrated by 3D seismic data. Some of the gas was permanently trapped (dry gas and CO2-rich gas) in the source rocks and aureoles. Combined with high-precision zircon ages and a time model for the PETM, our approach may give robust fluxes that can explain both the onset and the body of the PETM.

  18. Irradiated fuel behavior under accident heating conditions and correlation with fission gas release and swelling model (Chicago)

    International Nuclear Information System (INIS)

    Kryger, B.; Ducamp, F.; Combette, P.

    1981-08-01

    We analyse the mixed oxide fast fuel response to off normal conditions obtained by means of an out-of-pile transient simulation apparatus designed to provide direct observations (temperature, pressure, fuel motion) of fuel fission gas phenomena that might occur during the transients. The results are concerning fast transient tests (0,1 to 1 second) obtained with high gas concentration irradiated fuel (4 to 7 at % burn up, 0,4 cm 3 Xe + Kr /g.UPuO 2 ). The kinetics of fission gas release during the transients have been directly measured and then compared with the calculated results issued of the Chicago model. This model agrees, quite well, with other experiments done in the silene prompt reactor. Other gases than xenon and krypton (such as hydrogen and carbon monoxide) do not play any role in fuel behavior, since they have been completely ruled out

  19. Calculation of aerodynamics of aerosol filter designs for cleaning of heavy liquid metal cooler reactor gas loops

    International Nuclear Information System (INIS)

    Valery P Melnikov; Pyotr N Martynov; Albert K Papovyants; Ivan V Yagodkin

    2005-01-01

    Full text of publication follows: One of the basic performances of aerosol filters is the aerodynamic resistance to the flow of gaseous medium to be cleaned. Calculation of the aerodynamics of aerosol filters in reference to the gas loops of reactor installations with heavy liquid metal coolant (HLMC) allows the design of the structural components of filters to be optimized to provide minimum initial resistance values. It is established that owing to various factors aerosol particles of different concentration and disperse composition are present always in the gas spaces of heavy liquid metal cooled reactor gas loops. To prevent the negative effect of aerosols on the equipment of the gas loops, it is reasonable to use filters of multistep design with sections of preliminary and fine cleaning to catch micron and submicron particles, respectively. A computer program and technique have been developed to evaluate the aerodynamics of folded aerosol filters for different parameters of their structural components, taking account of the aerosol spectrum and concentration. The algorithm of the calculation is presented by the example of a two-step design assembled in single vessel; the filter dimensions and pattern of the air flow to be cleaned are determined under the given boundary conditions. The evaluation of the aerodynamic resistance of filters was performed with consideration for local resistances and resistances of all the structural components of the filter (sudden constriction, expansion, the flow in air channels, filtering material and so on). Correlations have been derived for the resistance of air channels, filtering materials of preliminary and fine cleaning sections as a function of such parameters as the section depth (50-500 mm), the height of separators (3,5-20 mm), the filtering surface area (1,5-30 m 2 ). Based on the calculation results, the auto-similarity domain was brought out for the minimal values of filter resistances as a function of the ratio of

  20. Gas release and foam formation during melting and fining of glass

    NARCIS (Netherlands)

    Beerkens, R.G.C.; Schaaf, van der J.

    2006-01-01

    A method for the prediction of gas evolution from a glass melt during fining processes has been described. This procedure is based on the assumption of thermodynamic equilibrium conditions between the species in the glass melt and co-existing gas phases. The method has been applied to estimate (a)

  1. Estimating release of polycyclic aromatic hydrocarbons from coal tar at manufactured-gas plant sites

    International Nuclear Information System (INIS)

    Loehr, R.C.; Rao, P.S.C.; Lee, L.S.; Okuda, I.

    1992-08-01

    One component of the EPRI's research on Envirorunental Behavior of Organic Substances (EBOS) consists of developing information and models to predict releases of monocyclic and polycyclic aromatic hydrocarbons (MAHs and PAHs) to groundwater from coal tars and contaminated soils at MGP sites. The results of this report focus primarily on release of PAHs from coal tars. There are at least two approaches to predicting the release of organic chemicals from coal tar to water. The simplest method to estimate aqueous concentrations is to assume that water solubility of a PAH compound released from the tar can be defined by equilibrium precipitation-dissolution reactions. Application of Raoult's law is another method to predict aqueous concentrations, which requires the assumption of ''ideal'' behavior for partitioning of PAHs between the tar and water phases. To evaluate the applicability of these two methods for predicting PAH releases, laboratory experiments were conducted with eight coal tar samples from former MGP sites across the country. Migration of chemicals in the environment and resulting contaminant plumes in groundwater are determined by leachate concentrations of the chemicals. The use of equilibrium precipitation-dissolution reactions will usually result in an overestimation of PAH concentrations in the leachate from a coal tar source, and thus the resulting PAH concentrations in groundwater. Raoult's law appears to be a more accurate approach to predicting the release of several PAHs from coal tars. Furthermore, if nonequilibrium conditions prevail, aqueous-phase PAH concentrations will be even lower than those predicted using Raoult's law

  2. A recommended approach to the National Pollutant Release Inventory (NPRI) for the upstream oil and gas industry : 2002 : CAC emissions

    International Nuclear Information System (INIS)

    2003-04-01

    The National Pollutant Release Inventory (NPRI) is a database of annual releases to air, water, land and off-site transfers of 273 specified pollutants. Environment Canada requires that the NPRI be reported annually. Criteria Air Contaminants (CAC) had to be reported for the first time in 2002. Air pollutants that contribute to the formation of ground level ozone and smog are included in the definition of CAC, along with any eye or respiratory irritants to both humans and animals. The substances of special interest to the petroleum industry are: oxides of nitrogen, sulphur dioxide, carbon monoxide, volatile organic compounds, total particulate matter, and particulate matters. This guide is intended to provide member companies of Canadian Association of Petroleum Producers (CAPP), operating upstream oil and gas facilities, with readily available data to determine the amount of CAC emissions released from their processes and equipment. Companies using these guidelines will be able to compare the performance of various upstream oil and gas companies more readily because the data is consistent. The scope of the project was described in section 1, and the sources of CAC emissions were identified in section 2. The reporting threshold was discussed in section 3. Data required for collection was outlined in section 4. Section 5 outlines how CAC emission quantities are determined. Calculation examples were provided in section 6 and definitions provided in section 7. 11 tabs., 1 fig

  3. Development and testing of on-line analytical instrumentation for alkali and heavy metal release in pressurised conversion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R; Haeyrinen, V; Oikari, R [Tampere Univ. of Technology (Finland)

    1997-10-01

    The purpose of the project is to demonstrate in industrial conditions and further develop the continuous alkali measurement method plasma excited alkali resonance line spectroscopy (PEARLS) developed at Tampere University of Technology (TUT). The demonstration takes place in joint measuring campaigns, where two other continuous alkali measurement methods, ELIF and surface ionisation, are being simultaneously demonstrated. A modification of PEARLS will also be developed for the continuous measurement of heavy metal concentrations. A market study of continuous measuring techniques for alkali and heavy metals is further part of the project. The method will be demonstrated in two pressurised fluidised bed combustion facilities. One of these is the 10 MW PCFB of Foster Wheeler Energia Oy in Karhula. The second one is yet to be decided. The first measuring campaign is scheduled for the spring of 1997 in Karhula. In 1996 the group at TUT participated in the performance of a market study regarding continuous measuring techniques for alkali and heavy metal concentrations. A draft report was submitted to and approved by the EC. Development work on PEARLS in 1996 has centered around the construction of a calibration device for alkali measurements. The device can be used by all three measuring techniques in the project to check readings against a known alkali concentration at controlled and known conditions. In 1996 PEARLS was applied for alkali measurement at several pressurised combustion installations of laboratory and industrial pilot scale

  4. LP compressor blade vibration characteristics at starting conditions of a 100 MW heavy-duty gas turbine

    International Nuclear Information System (INIS)

    Lee, An Sung; Vedichtchev, Alexandre F.

    2004-01-01

    In this paper are presented the blade vibration characteristics at the starting conditions of the low pressure multistage axial compressor of heavy-duty 100 MW gas turbine. Vibration data have been collected through strain gauges during aerodynamic tests of the model compressor. The influences of operating modes at the starting conditions are investigated upon the compressor blade vibrations. The exciting mechanisms and features of blade vibrations are investigated at the surge, rotating stall, and buffeting flutter. The influences of operating modes upon blade dynamic stresses are investigated for the first and second stages. It is shown that a high dynamic stress peak of 120 MPa can occur in the first stage blades due to resonances with stall cell excitations or with inlet strut wake excitations at the stalled conditions

  5. Computational analysis of transient gas release from a high pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Pedro, G.; Oshkai, P.; Djilali, N. [Victoria Univ., BC (Canada). Inst. for Integrated Energy Systems; Penau, F. [CERAM Euro-American Inst. of Technology, Sophia Antipolis (France)

    2006-07-01

    Gas jets exiting from compressed vessels can undergo several regimes as the pressure in the vessel decreases, and a greater understanding of the characteristics of gas jets is needed to determine safety requirements in the transport, distribution, and use of hydrogen. This paper provided a study of the bow shock waves that typically occur during the initial stage of a gas jet incident. The transient behaviour of an initiated jet was investigated using unsteady, compressible flow simulations. The gas was considered to be ideal, and the domain was considered to be axisymmetric. Tank pressure for the analysis was set at a value of 100 atm. Jet structure was examined, as well as the shock structures and separation due to adverse pressure gradients at the nozzle. Shock structure displacement was also characterized.

  6. Mechanistic analysis of double-shell tank gas release. Progress report, November 1990

    Energy Technology Data Exchange (ETDEWEB)

    Allemann, R.T.; Antoniak, Z.I.; Friley, J.R.; Haines, C.E.; Liljegren, L.M.; Somasundaram, S.

    1991-12-01

    Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodically releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.

  7. Harnessing the potential - Atlantic Canada's oil and gas industry : Newfoundland Ocean Industries special releases or publications

    International Nuclear Information System (INIS)

    1998-07-01

    A comprehensive overview of Atlantic Canada's oil and gas industry is presented, demonstrating the importance of oil and gas resources and their related industries to Atlantic Canada. The objective of the report is to provide a basis for a strategy to optimize opportunities within the region from the oil and gas sector. The report reviews the current status of the industry, including the region's resource potential and the oil and gas developments currently underway. The evolution of the oil and gas industry is discussed in terms of value chain components. A broad assessment of the region's supply, labour force, infrastructure, training, and research and development capabilities is presented, followed by a description of the industry's potential, its regulatory framework and the barriers and constraints affecting industry development. Appendices contain a chronological history of major events in Atlantic Canada's oil and gas industry (Appendix A); and overview of the Atlantic Accord and the Canada-Nova Scotia Accord's equalization offset provisions (Appendix B); a value chain matrix, detailing some 60 categories of industry requirements and a capsule assessment of the region's ability to meet them (Appendix C); and a listing of research and development institutions in Atlantic Canada, including their areas of specialization (Appendix D)

  8. Diffusion and release of noble gas and halogen fission products with several days half-life in UO2 particle

    International Nuclear Information System (INIS)

    Fang Chao

    2013-01-01

    The exact solutions of diffusion and release model of noble gas and halogen fission products in UO 2 particle of HTGR were built under the conditions of adsorption effect and other physical processes. The corresponding release fractions (F(t)) and the ratio of release and productive amounts (R(t)/B (t)) of fission products were also derived. Furthermore, the F(t) and R(t)/B(t) of 131 I, 131 IXe m , 133 Xe and 133 Xe m whose half-lifes are several days in UO 2 particle with the exact solutions, approximate solutions and corresponding numerical solutions under different temperature histories of reactor core were investigated. The results show that the F(t) and R(t)/B(t) are different in numerical values unless the time of release is long enough. The properties of conservation of exact solutions are much more reasonable than the ones of approximate solutions. It is also found that the results of exact solutions approach the actual working conditions more than the approximate and numerical solutions. (author)

  9. The calculating methods of the release of airborne radionuclides to environment during the normal operation of a module high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Liu Yuanzhong

    1993-01-01

    The calculations of the release of radionuclides to environment are the basis of environmental impact assessment during the normal operation of a module high temperature gas-cooled reactor of the Institute of Nuclear Energy Technology, Tsinghua University, China. According to the features of the reactor it is pointed out that only five sources of the airborne radioactive materials released to environment are important. They are: (1) the activation of the air in the reactor cavity; (2) the escape from the primary coolant systems; (3) the release of radioactively contaminated helium from storage tanks; (4) the release of radioactively contaminated helium from the gas evacuation system of fuel load and unload system; (5) the leakage of the vapour from water-steam loop. In accordance with five release sources the calculating methods of radionuclides released to environment are worked out respectively and the respective calculating formulas are derived for the normal operation of the reactor

  10. Analysis of UO2 fuel structure for low and high burn-up and its impact on fission gas release

    International Nuclear Information System (INIS)

    Szuta, M.; El-Koliel, M.S.

    1999-01-01

    During irradiation, uranium dioxide (UO 2 ) fuel undergo important restructuring mainly represented by densification and swelling, void migration, equiaxed grain growth, grain subdivision, and the formation of columnar grains. The purpose of this study is to obtain a comprehensive picture of the phenomenon of equiaxed grain growth in UO 2 ceramic material. The change of the grain size in high-density uranium dioxide as a function of temperature, initial grain size, time, and burnup is calculated. Algorithm of fission gas release from UO 2 fuel during high temperature irradiation at high burnup taking into account grain growth effect is presented. Theoretical results are compared with experimental data. (author)

  11. Microstructural change and its influence on fission gas release in high burnup UO 2 fuel

    Science.gov (United States)

    Une, K.; Nogita, K.; Kashibe, S.; Imamura, M.

    1992-06-01

    The microstructural change of UO 2 fuel pellets (burnup: 6-83 GWd/t), base irradiated under LWR conditions, has been studied by detailed postirradiation examinations. The lattice parameter near the fuel rim in the irradiated UO 2 increased with burnup and appeared to become constant beyond about 50 GWd/t. This lattice dilation was mainly due to the accumulation of radiation induced point defects. Moreover, the dislocation density in the UO 2 matrix developed progressively with burnup, and eventually the tangled dislocations organized many sub-grain boundaries in the highest burnup fuel of 83 GWd/t. This sub-grain structure induced by accumulated radiation damage was compatible in appearance with SEM fractography results which revealed sub-divided grains of sub-micron size in as-fabricated grains. The influence of burnup on 85Kr release from the UO 2 fuels has been examined by means of a postirradiation annealing technique. The higher fractional release of high burnup fuels was mainly due to the burnup dependence of the fractional burst release evolved on temperature ramp. The fractional burst release was represented in terms of the square root of burnup from 6 to 83 GWd/t.

  12. Swift heavy ion induced modification in polycarbonate membrane for gas separation

    International Nuclear Information System (INIS)

    Rajesh Kumar; Prasad, Rajendra; Vijay, Y.K.; Das, D.

    2003-01-01

    Polymeric membranes are extensively used for commercial gas separation applications. Makrofol-KG (polycarbonate) is a glassy polymer. 40 μm thick sheet of Makrofol-KG was irradiated with 40 Ar (14.9 MeV/n) of fluence 10 3 ions/cm 2 and 20 μm thick sheet with 5.3 MeV α-particles of fluence 10 7 ions/cm 2 . The permeability of these polycarbonate membranes for H 2 and CO 2 was measured and also after etching in 6 N NaOH at 60 degC for different periods. Permeability is found to be increased with etching time. At a definite time, critical etching time, the permeability rapidly increases in PC. Positron annihilation lifetimes for unirradiated and irradiated membranes were measured with fast fast coincidence system to study the correlation of free volume hole concentration with gas separation properties. (author)

  13. Numerical predictions of the separation of heavy components inside the trace gas concentrator

    International Nuclear Information System (INIS)

    Mo, J.D.

    1995-01-01

    The component with a heavier molecular weight can be separated from the one with a lighter molecular weight in a binary mixture by applying an appropriate pressure gradient. A centrifugal force field effectively generates the required pressure gradient and a favorable flow field along the radial direction in a trace gas concentrator for such an application. This paper presents the numerical predictions of the mass separation inside a trace gas concentrator, which enriches Xenon in air. A Navier-Stokes solver in primitive variables using a pressure based algorithm has been applied to solve for the flow fields. Subsequently, the transport equations with a strong centrifugal field are solved for the mass concentration. This study is the continued effort for the proof-of-concept of centrifugal separation of components with a considerable difference in their molecular weight in a binary mixture. The significant effects of rotational speed, flow field, and the geometrical configuration on the mass separation are presented in this paper

  14. Liquefied natural gas as a transportation fuel for heavy-duty trucks: Volume I

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This document contains Volume 1 of a three-volume manual designed for use with a 2- to 3-day liquefied natural gas (LNG) training course. Transportation and off-road agricultural, mining, construction, and industrial applications are discussed. This volume provides a brief introduction to the physics and chemistry of LNG; an overview of several ongoing LNG projects, economic considerations, LNG fuel station technology, LNG vehicles, and a summary of federal government programs that encourage conversion to LNG.

  15. Natural gas application in light- and heavy-duty vehicles in Brazil: panorama, technological routes and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Guilherme Bastos, Cordeiro de Melo, Tadeu Cavalcante; Leao, Raphael Riemke de Campos Cesar; Iaccarino, Fernando Aniello; Figueiredo Moreira, Marcia

    2007-07-01

    The Brazilian CNG light-duty vehicle fleet has currently reached more than 1,300,000 units. This growth increased in the late 1990's, when CNG was approved for use in passenger cars. In 2001, the IBAMA (Brazilian Institute for Environment and Natural Renewable Resources), concerned with this uncontrolled growth, published CONAMA (National Environmental Council, controlled by IBAMA) resolution 291, which establishes rules for CNG conversion kit environmental certification.This paper discusses the technological challenges for CNG-converted vehicles to comply with PROCONVE (Brazilian Program for Automotive Air Pollution Control) emission limits. In the 1980's, because of the oil crisis, Natural Gas (NG) emerged as a fuel with great potential to replace Diesel in heavy-duty vehicles. Some experiences were conducted for partial conversions from Diesel to NG (Diesel-gas). Other experiences using NG Otto Cycle buses were conducted in some cities, but have not expanded. Another technological route called 'Ottolization' (Diesel to Otto cycle convertion) appeared recently. Population increase and the great growth in vehicle fleet promote a constant concern with automotive emissions. More restrictive emission limits, high international oil prices, and the strategic interest in replacing Diesel imports, altogether form an interesting scenario for CNG propagation to public transportation in the main Brazilian metropolises.

  16. Numerical Investigation of Fuel Distribution Effect on Flow and Temperature Field in a Heavy Duty Gas Turbine Combustor

    Science.gov (United States)

    Deng, Xiaowen; Xing, Li; Yin, Hong; Tian, Feng; Zhang, Qun

    2018-03-01

    Multiple-swirlers structure is commonly adopted for combustion design strategy in heavy duty gas turbine. The multiple-swirlers structure might shorten the flame brush length and reduce emissions. In engineering application, small amount of gas fuel is distributed for non-premixed combustion as a pilot flame while most fuel is supplied to main burner for premixed combustion. The effect of fuel distribution on the flow and temperature field related to the combustor performance is a significant issue. This paper investigates the fuel distribution effect on the combustor performance by adjusting the pilot/main burner fuel percentage. Five pilot fuel distribution schemes are considered including 3 %, 5 %, 7 %, 10 % and 13 %. Altogether five pilot fuel distribution schemes are computed and deliberately examined. The flow field and temperature field are compared, especially on the multiple-swirlers flow field. Computational results show that there is the optimum value for the base load of combustion condition. The pilot fuel percentage curve is calculated to optimize the combustion operation. Under the combustor structure and fuel distribution scheme, the combustion achieves high efficiency with acceptable OTDF and low NOX emission. Besides, the CO emission is also presented.

  17. The use of water curtains to protect firemen in case of heavy gas dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Bara, A.; Dusserre, G. [Ecole Nationale Superieure des Techniques Industrielles et des Mines d`Ales (France). Lab. Genie de l`Environnement Industriel

    1997-05-01

    The aim of this paper is to study the effectiveness of the water curtains used by firemen in France to protect people fighting chemical spillage. The effectiveness of these barriers is a reduction in concentration behind it by a factor of 10 at a distance of approximately 13 m and a factor of 3 at a distance of approximately 20 m in the case of ammonia releases. The results of similar studies of a wide variety of toxic gases will provide a quick and reliable tool for firefighters, which will help to define at what distance to place the curtain and predict the concentrations behind it. (UK)

  18. Possible effects of oxidation on the transient release of fission gas from UO2

    International Nuclear Information System (INIS)

    Stoner, H.C.; Matthews, J.R.; Wood, M.H.

    1981-01-01

    The effect of varying the fuel composition from UO 2 to UOsub(2.3), on the transient behaviour of fission gas is simulated on the assumption that surface diffusion behaves in a similar manner to volume diffusion. The results may help in the understanding of fuel behaviour after pin failure in accident conditions in thermal reactor systems. (author)

  19. Release of iodine radionuclides from gas media in a system of selective block sorbents

    International Nuclear Information System (INIS)

    Moskvin, L.N.; Miroshnikov, V.S.; Mel'nikov, V.A.; Chetverikov, V.V.

    1979-01-01

    A scheme of extracting iodine radionuclides from gas flows in a system of selective sorbents has been developed. The method provides separation of three forms of iodine: the aerosol component, the elementary iodine and organic-iodine compounds. Aerosols are trapped by a mechanical filter made of porous polytetrafluoroethylene with pores of no more than 1 μm. Silver-based sorbents for the elementary iodine are made by sintering the granular polytetrafluoroethylene (the size of granules is 0.1-0.5 mm) with of finely dispersed solver (5% mass). Organic iodine compounds are extracted by a silica sorbent impregnated with silver nitrate. The efficiency of sorbents was tested in gas flows with a known content of 131 I in the form of elementary iodine and methyl iodide. The results of experiments show that the efficiency of sorption of elementary iodine by a metallic-silver sorbent and of methyl iodide by a SiO 2 /AgNO 3 sorbent constitutes no less than 99% at a flow rate of up to 200 l/h. The iodine has been extracted at a flow rate of 100 l/h during 100 hours and for that time the efficiency of the iodine sorbtion has not changed. The suggested variant of extracting iodine radionuclides from gaseous media can be used both for fast control of iodine content in gas blowoffs and for researches aimed at studying the distribution of iodine forms in steam-and-gas media depending on nuclear plant operating conditions

  20. Future methane emissions from the heavy-duty natural gas transportation sector for stasis, high, medium, and low scenarios in 2035.

    Science.gov (United States)

    Clark, Nigel N; Johnson, Derek R; McKain, David L; Wayne, W Scott; Li, Hailin; Rudek, Joseph; Mongold, Ronald A; Sandoval, Cesar; Covington, April N; Hailer, John T

    2017-12-01

    Today's heavy-duty natural gas-fueled fleet is estimated to represent less than 2% of the total fleet. However, over the next couple of decades, predictions are that the percentage could grow to represent as much as 50%. Although fueling switching to natural gas could provide a climate benefit relative to diesel fuel, the potential for emissions of methane (a potent greenhouse gas) from natural gas-fueled vehicles has been identified as a concern. Since today's heavy-duty natural gas-fueled fleet penetration is low, today's total fleet-wide emissions will be also be low regardless of per vehicle emissions. However, predicted growth could result in a significant quantity of methane emissions. To evaluate this potential and identify effective options for minimizing emissions, future growth scenarios of heavy-duty natural gas-fueled vehicles, and compressed natural gas and liquefied natural gas fueling stations that serve them, have been developed for 2035, when the populations could be significant. The scenarios rely on the most recent measurement campaign of the latest manufactured technology, equipment, and vehicles reported in a companion paper as well as projections of technology and practice advances. These "pump-to-wheels"(PTW) projections do not include methane emissions outside of the bounds of the vehicles and fuel stations themselves and should not be confused with a complete wells-to-wheels analysis. Stasis, high, medium, and low scenario PTW emissions projections for 2035 were 1.32%, 0.67%, 0.33%, and 0.15% of the fuel used. The scenarios highlight that a large emissions reductions could be realized with closed crankcase operation, improved best practices, and implementation of vent mitigation technologies. Recognition of the potential pathways for emissions reductions could further enhance the heavy-duty transportation sectors ability to reduce carbon emissions. Newly collected pump-to-wheels methane emissions data for current natural gas technologies

  1. Experimental and theoretical studies on water and gas release from heated concrete

    International Nuclear Information System (INIS)

    McCormack, J.D.; Postma, A.K.

    1977-01-01

    Procedures currently used in licensing of nuclear facilities require analysis of postulated accidents which are more severe than ''design basis'' events. For breeder program reactors, some accidents in this severe category involve spillage of sodium coolant onto concrete protected by a steel liner. Heat transfer through the liner heats the concrete, causing a part of the mixing water and other gases to be driven off. These gases would add to pressure in the containment atmosphere, and the water vapor can form hydrogen if it contacts sodium. Evaluations of containment integrity for such postulated accidents will be aided by knowledge of how much water and other gases are released from heated concrete. The report presents results of a research effort at Hanford Engineering Development Laboratory designed to improve understanding of the release of water and gases from heated concrete

  2. Aerosol and activity release from contaminated sodium pools in inert gas atomosphere

    International Nuclear Information System (INIS)

    Sauter, H.; Schuetz, W.

    1983-07-01

    A description is given of parameters and results from technical scale experiments (1 kg Na, 531 cm 2 pool surface area, 481-632 0 C pool temperature, UO 2 -, NaI-, SrO-admixtures from 0.2 up to 20 g, 2.2 m 3 vessel to be heated up to 130 0 C) and from laboratory scale experiments in a glove box (100 g Na, 38.5 cm 2 pool surface area, 550 0 C pool temperature, UO 2 and SrO admixtures from 0.2 up to 5 g, with the released quantities being sucked into cold traps and filters). The main objective of the tests was to determine the retention factors RF for U, I and Sr including their time behaviour as well as differences in local deposition. Liquid sodium has a very high retention capability for U and Sr; in the early phase (about 10% of the pool vaporized), RF (U) is of the order of 10 3 to 10 4 , and RF (Sr) of the order of 500, with increasing tendencies with time. RF (I), however, was found to be between 1 and 10. The iodine release may be explained by evaporation, whereas strong evidence exists for mechanical release processes (small particle release) in case of UO 2 and SrO. A best-fit formula is given for the specific evaporation rate of sodium, based on its proportionality to the vapor pressure. The sodium aerosol system was investigated with respect to mass concentration, particle size spectrum and deposition behaviour. Model calculations were performed using the PARDISEKO computer code. Agreement with the experiment was achieved after introducing a turbulent deposition module into the code. (orig./HP) [de

  3. Integrated environmental modeling system for noble gas releases at the Savannah River Plant

    International Nuclear Information System (INIS)

    Cooper, R.E.

    1973-01-01

    The Savannah River Plant (SRP) is a large nuclear complex engaged in varied activities and is the AEC's major site for the production of weapons material. As a result of these activities, there are continuous and intermittent releases of radioactive gases to the atmosphere. Of these releases, the noble gases constitute about 11 percent of the total man-rem exposure to the population out to a distance of 100 km. Although SRP has an extensive radiological monitoring program, an environmental modeling system is necessary for adequately estimating effects on the environment. The integrated environmental modeling system in use at SRP consists of a series of computer programs that generate and use a library of environmental effects data as a function of azimuth and distance. Annual average atmospheric dispersion and azimuthal distribution of material assumed to be released as unit sources is estimated from a 2-year meteorological data base--assuming an arbitrary point of origin. The basic library of data consists of: ground-level concentrations according to isotope, and whole body gamma dose calculations that account for the total spatial distribution at discrete energy levels. These data are normalized to tritium measurements, and are subsequently used to generate similar library data that pertain to specific source locations, but always with respect to the same population grid. Thus, the total additive effects from all source points, both on- and off-site, can be estimated. The final program uses the library data to estimate population exposures for specified releases and source points for the nuclides of interest (including noble gases). Multiple source points are considered within a single pass to obtain the integrated effects from all sources

  4. Operational characteristics of a high voltage plasma focus device working with deuterium and heavy gas mixture

    International Nuclear Information System (INIS)

    Zoita, V.; Presura, R.; Gherendi, F.; Dumitrescu-Zoita, C.; Aliaga, R.

    1992-01-01

    The addition of a few neon percents to the deuterium gas filling of a medium energy plasma focus device (PFD) changes dramatically the radiation characteristics of the discharge as well as the pinch configuration. One exceptional result is the generation of high aspect ratio pinches shown clearly and reproducibly on X-ray pinhole camera images and on schlieren pictures. Another remarkable result is that these pinches which show no macroscopic instabilities copiously produce neutrons and hard X-rays. This confirms an experimental fact previously identified on a lower voltage PFD: the macroscopic instabilities do not play the decisive role in the neutronic performance of medium energy PFD's. (Author)

  5. Management of gas releases with greenhouse effect: which economical tools?; Maitriser les emissions de gaz a effet de serre: quels instruments economiques?

    Energy Technology Data Exchange (ETDEWEB)

    Lepeltier, Serge [Senat, Paris (France)

    2000-06-09

    The climatic change represents the most severe danger to the durable world development, public health and future prosperity. This document concerning the gas releases with greenhouse effect is a report of the Senate Planning delegation regarding the economic and fiscal tools envisaging abatement of releases of gases with greenhouse effect. These issues are presented in four chapters titled as follows: 1. Since the scientific evidencing, requirement of managing the releases of gas with greenhouse effect has been unanimously recognized at the summits of Rio (1992) and Kyoto (1997); 2. The economic theory suggests instruments for reducing the gas releases with greenhouse effect at a minimum cost; 3. Challenges and ways of international cooperation in the field of climatic change; 4. Joining the political will with the pragmatic use of the economic instruments at national scale. The document contains a synthesis of proposals directed towards the following goals: international negotiations relating to climatic change; creating the community framework of managing the gas releases resulting in greenhouse effect; establishing national measures for managing the gas releases leading to greenhouse effect; actions to be undertaken by the territorial collectivities.

  6. Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate

    International Nuclear Information System (INIS)

    Fan, Chuan Gang; Li, Ying Zhen; Ingason, Haukur; Lönnermark, Anders

    2016-01-01

    Highlights: • The effect of tunnel cross section together with ventilation velocity was studied. • Ceiling temperature varies clearly with tunnel height, but little with tunnel width. • Downstream temperature decreases with increasing tunnel dimensions. • HRR is an important factor that influences decay rate of excess gas temperature. • An equation considering both tunnel dimensions and HRR was developed. - Abstract: Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.

  7. Heat treatments of irradiated uranium oxide in a pressurised water reactor (P.W.R.): swelling and fission gas release

    International Nuclear Information System (INIS)

    Zacharie, I.

    1997-01-01

    In order to keep pressurised water reactors at a top level of safety, it is necessary to understand the chemical and mechanical interaction between the cladding and the fuel pellet due to a temperature increase during a rapid change in reactor. In this process, the swelling of uranium oxide plays an important role. It comes from a bubble precipitation of fission gases which are released when they are in contact with the outside. Therefore, the aim of this thesis consists in acquiring a better understanding of the mechanisms which come into play. Uranium oxide samples, from a two cycles irradiated fuel, first have been thermal treated between 1000 deg C and 1700 deg C for 5 minutes to ten hours. The gas release amount related to time has been measured for each treatment. The comparison of the experimental results with a numerical model has proved satisfactory: it seems that the gases release, after the formation of intergranular tunnels, is controlled by the diffusion phenomena. Afterwards, the swelling was measured on the samples. The microscopic examination shows that the bubbles are located in the grain boundaries and have a lenticular shape. The swelling can be explained by the bubbles coalescence and a model was developed based on this observation. An equation allows to calculate the intergranular swelling in function of time and temperature. The study gives the opportunity to predict the fission gases behaviour during a fuel temperature increase. (author)

  8. Low NO subx heavy fuel combustor concept program. Phase 1A: Coal gas addendum

    Science.gov (United States)

    Rosfjord, T.; Sederquist, R.

    1982-01-01

    The performance and emissions from a rich-lean combustor fired on simulated coal gas fuels were investigated using a 12.7-cm diameter axially-staged burner originally designed for operation with high heating value liquid fuels. A simple, tubular fuel injector was substituted for the liquid fuel nozzle; no other combustor modifications were made. Four test fuels were studied including three chemically bound nitrogen-free gas mixtures with higher heating values of 88, 227, and 308 kj/mol (103, 258 and 349 Btu/scf), and a 227 kj/mol (258 Btu/scf) heating value doped with ammonia to produce a fuel nitrogen content of 0.5% (wt). Stable, ultra-low nitrogen oxide, smoke-free combustion was attained for the nitrogen-free fuels. Results with the doped fuel indicated that less than 5% conversion of NH3 to nitrogen oxide levels below Environmental Protection Agency limits could be achieved. In some instances, excessive CO levels were encountered. It is shown that use of a burner design employing a less fuel-rich primary zone than that found optimum for liquid fuels would yield more acceptable CO emissions.

  9. Experimental study of collective acceleration of light and heavy ions from a localized gas cloud

    International Nuclear Information System (INIS)

    Floyd, L.E. IV.

    1984-01-01

    An experimental investigation into the collective acceleration of various gaseous atoms (H, D, He, N, Ne, Ar, Kr, Xe) is presented. A localized gas cloud is formed using a fast rise puff valve immediately downstream of an intense relativistic electron beam diode. The diode consists of a tungsten needle cathode and a stainless steel anode with a hole on axis. The diode is driven by an electron beam generator system consisting of a Marx generator, Blumlein line, and transmission line transformer. It produces a 1.5 MV, 35 kA, 30 ns FWHM electrical pulse measured at the diode. The resulting electron beam has nu/γ approx. 1 and is about six times the vacuum space charge limiting current in the downstream drift chamber. Ions are produced during the impact of the electron beam with the gas cloud and are accelerated to high energy by collective effects associated with the electron beam space charge. Ion energy diagnostics include fast neutron counting, nuclear activation of stacked foils, measurement of time of flight using direct intercept current collector probes, and range/energy analysis of nuclear track plates. The principal result of the experiments was that all ion species were accelerated to a maximum velocity of 0.1c, corresponding to an energy of 4.7 MeV/nucleon. Energy spectra obtained from stacked foil activation for accelerated hydrogen and deuterium were found to be approximately exponential in character

  10. When soils become sediments: Large-scale storage of soils in sandpits and lakes and the impact of reduction kinetics on heavy metals and arsenic release to groundwater.

    Science.gov (United States)

    Vink, Jos P M; van Zomeren, Andre; Dijkstra, Joris J; Comans, Rob N J

    2017-08-01

    Simulating the storage of aerobic soils under water, the chemical speciation of heavy metals and arsenic was studied over a long-term reduction period. Time-dynamic and redox-discrete measurements in reactors were used to study geochemical changes. Large kinetic differences in the net-complexation quantities of heavy metals with sulfides was observed, and elevated pore water concentrations remained for a prolonged period (>1 year) specifically for As, B, Ba, Co, Mo, and Ni. Arsenic is associated to the iron phases as a co-precipitate or sorbed fraction to Fe-(hydr)oxides, and it is being released into solution as a consequence of the reduction of iron. The composition of dissolved organic matter (DOM) in reducing pore water was monitored, and relative contributions of fulvic, humic and hydrophylic compounds were measured via analytical batch procedures. Quantitative and qualitative shifts in organic compounds occur during reduction; DOM increased up to a factor 10, while fulvic acids become dominant over humic acids which disappear altogether as reduction progresses. Both the hydrophobic and hydrophilic fractions increase and may even become the dominant fraction. Reactive amorphous and crystalline iron phases, as well as dissolved FeII/FeIII speciation, were measured and used as input for the geochemical model to improve predictions for risk assessment to suboxic and anaerobic environments. The release of arsenic is related to readily reducible iron fractions that may be identified by 1 mM CaCl 2 extraction procedure. Including DOM concentration shifts and compositional changes during reduction significantly improved model simulations, enabling the prediction of peak concentrations and identification of soils with increased emission risk. Practical methods are suggested to facilitate the practice of environmentally acceptable soil storage under water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Comparison of Therapeutic Efficacies of Norethisterone, Tranexamic Acid and Levonorgestrel-Releasing Intrauterine System for the Treatment of Heavy Menstrual Bleeding: A Randomized Controlled Study.

    Science.gov (United States)

    Kiseli, Mine; Kayikcioglu, Fulya; Evliyaoglu, Ozlem; Haberal, Ali

    2016-01-01

    Our aim was to compare the therapeutic efficacies of norethisterone acid (NETA), tranexamic acid and levonorgestrel-releasing intrauterine system (LNG-IUS) in treating idiopathic heavy menstrual bleeding (HMB). Women with heavy uterine bleeding were randomized to receive NETA, tranexamic acid or LNG-IUS for 6 months. The primary outcome was a decrease in menstrual bleeding as assessed by pictorial blood loss assessment charts and hematological parameters analyzed at the 1st, 3rd and 6th months. Health-related quality of life (QOL) variables were also recorded and analyzed. Twenty-eight patients were enrolled in each treatment group, but the results of only 62 were evaluated. NETA, tranexamic acid, and LNG-IUS reduced menstrual blood loss (MBL) by 53.1, 60.8, and 85.8%, respectively, at the 6th month. LNG-IUS was more effective than NETA and tranexamic acid in decreasing MBL. LNG-IUS was also more efficient than tranexamic acid in correcting anemia related to menorrhagia. Satisfaction rates were comparable among the NETA (70%), tranexamic acid (63%) and LNG-IUS (77%) groups. QOL in physical aspects increased significantly in the tranexamic acid and LNG-IUS groups. The positive effect of LNG-IUS on QOL parameters, as well as its high efficacy, makes it a first-line option for HMB. © 2016 S. Karger AG, Basel.

  12. Collimator system for the stabilization of the dynamical residual-gas pressure in the heavy-ion synchrotron SIS18; Kollimatorsystem zur Stabilisierung des dynamischen Restgasdruckes im Schwerionensynchrotron SIS18

    Energy Technology Data Exchange (ETDEWEB)

    Omet, Carsten

    2009-01-15

    In order to achieve higher beam intensities of heavy ion beams in ring accelerators, low charge state ions can be used. By lowering the charge state, the space charge limit is shifted to higher particle numbers and stripping losses can be avoided. During test operation of the SIS18 at GSI with high intensity low charge state heavy ion beams, strong intensity dependent beam losses have been observed. It was found that these beam losses are originated to a large extent by the change of charge state of the circulating ions during collisions with residual gas atoms. The resulting deviation of m/q relative to the reference ion leads, in combination with dispersive elements in the ion optic lattice, to a modified trajectory, followed by the loss of the ion on the beam pipe. At the impact position, loosely bound residual gas molecules are released by ion stimulated desorption which increases the residual gas pressure locally. This pressure rise itself enhances the charge exchange rate, which can develop into a self amplifying process of pressure rise and subsequent beam loss. A method for the stabilization of the dynamic residual gas pressure is the use of special catcher systems, which minimize the production of desorption gases and remove them by strong pumping. Therefore, the pressure on the beam axis should remain as stable as possible. Other processes, e.g. Coulomb scattering of the beam ions by residual gas particles and unavoidable systematic beam losses can increase the gas pressure additionally. The pressure in the accelerator is further subjected to ionization of the residual gas atoms themselves, thermal out gassing of the beam pipes, insertions and pumps. In this work, a detailed numerical model of the interplay between the residual gas pressure dynamics in the accelerator, possible stabilization measures, e.g. by catchers and the resulting beam life time has been developed. The forecasted beam life times and pressures are verified by machine experiments, as

  13. Containment for Heavy-Water Gas-Cooled Reactors; Le Confinement des Reacteurs a Eau Lourde Refroidis par Gaz

    Energy Technology Data Exchange (ETDEWEB)

    Verstraete, P.; Lehmann, D.; Lafitte, R. [Bonard et Gardel, Ingenieurs-Conseils, Lausanne (Switzerland)

    1967-09-15

    The safety principles applicable to heavy-water, gas-cooled reactors are outlined, with a view to establishing containment specifications adapted to the sites available in Switzerland for the construction of nuclear plants. These specifications are derived from dose rates considered acceptable, in the event of a serious reactor accident, for persons living near the plant, and are based on-meteorological and demographic conditions representative of the majority of the country's sites. The authors consider various designs for the containment shell, taking into account the conditions which would exist in the shell after the maximum credible accident. The following types of shell are studied: pre-stressed concrete; pre-stressed concrete with steel dome; pre-stressed concrete with inner, leakproof steel lining; steel with concrete side shield to protect against radiation; double shell. The degree of leak proofing of the shells studied is regarded as a feature of the particular design and not as a fixed constructional specification. The authors assess the leak proofing properties of each type of shell and establish building costs for each of them on the basis of precise plans, with the collaboration of various specialized firms. They estimate the effectiveness of the various shells from a safety standpoint, in relation to different emergency procedures, in particular release into the atmosphere through appropriate filters and decontamination of the air within the shell by recycling through batteries of filters. The paper contains a very detailed comparison of about 10 cases corresponding to various combinations of design and emergency procedure; the comparison was made using a computer programme specially established for the purpose. The results are compared with those for a reactor of the same type and power, but assembled together with the heat exchangers in a pre-stressed concrete shell. (author) [French] Les principes de securite des reacteurs a eau lourde refroidis

  14. New tracers identify hydraulic fracturing fluids and accidental releases from oil and gas operations.

    Science.gov (United States)

    Warner, N R; Darrah, T H; Jackson, R B; Millot, R; Kloppmann, W; Vengosh, A

    2014-11-04

    Identifying the geochemical fingerprints of fluids that return to the surface after high volume hydraulic fracturing of unconventional oil and gas reservoirs has important applications for assessing hydrocarbon resource recovery, environmental impacts, and wastewater treatment and disposal. Here, we report for the first time, novel diagnostic elemental and isotopic signatures (B/Cl, Li/Cl, δ11B, and δ7Li) useful for characterizing hydraulic fracturing flowback fluids (HFFF) and distinguishing sources of HFFF in the environment. Data from 39 HFFFs and produced water samples show that B/Cl (>0.001), Li/Cl (>0.002), δ11B (25-31‰) and δ7Li (6-10‰) compositions of HFFF from the Marcellus and Fayetteville black shale formations were distinct in most cases from produced waters sampled from conventional oil and gas wells. We posit that boron isotope geochemistry can be used to quantify small fractions (∼0.1%) of HFFF in contaminated fresh water and likely be applied universally to trace HFFF in other basins. The novel environmental application of this diagnostic isotopic tool is validated by examining the composition of effluent discharge from an oil and gas brine treatment facility in Pennsylvania and an accidental spill site in West Virginia. We hypothesize that the boron and lithium are mobilized from exchangeable sites on clay minerals in the shale formations during the hydraulic fracturing process, resulting in the relative enrichment of boron and lithium in HFFF.

  15. Energy and greenhouse gas profile of the Nouvelle Aquitaine region. Release 2017

    International Nuclear Information System (INIS)

    Rousset, Alain; Poitevin, Lionel; Loeb, Amandine; Philippot, Herve; Rebouillat, Lea; Jacquelin, Antoine

    2017-06-01

    This publication first proposes graphs and comments characterising final energy consumption of the Nouvelle Aquitaine region: regional situation in 2015 (analysis per sector and per energy), primary resources, social-economic analysis (energy bill, level of energy poverty, burden due to old housing and commuting for households), evolution of energy consumption between 2005 and 2015 (per sector, per source of energy, evolution of energy intensity and of the energy bill). The next part addresses greenhouse gas emissions: regional situation in 2015 (distribution in terms of emission type and per gas), evolutions between 1990 and 2015, evolutions per sector. The third part addresses renewable energies: regional situation for the different types of renewable energy, comparison with final energy consumption, comparison with national data, production evolutions, focus per sector (wood and wood by-products, heat pumps in the housing sector, urban waste valorisation units, biogas valorisation, bio-fuels, wind energy, hydroelectricity, solar photovoltaic). The last part recalls national objectives related to energy, to greenhouse gas emissions for France and for the region, in relationship with the law on energy transition and for a green growth

  16. Lander based hydroacoustic monitoring of marine single bubble releases in Eckernförde Bay utilizing the multibeam based GasQuant II system.

    Science.gov (United States)

    Urban, Peter; Schneider von Deimling, Jens; Greinert, Jens

    2015-04-01

    The GEOMAR Helmholtz Centre for Ocean Research Kiel is currently developing a Imagenex Delta T based lander system for monitoring and quantifying marine gas release (bubbles). The GasQuant II is built as the successor of the GasQuant I system (Greinert, 2008), that has been successfully used for monitoring tempo-spatial variability of gas release in the past (Schneider von Deimling et al., 2010). The new system is lightweight (40 kg), energy efficient, flexible to use and built for ROV deployment with autonomous operation of up to three days. A prototype has been successfully deployed in Eckernförde Bay during the R/V ALKOR cruise AL447 in October/November 2014 to monitor the tempo-spatial variability of gas bubble seepage and to detect a possible correlation with tidal variations. Two deployments, one in forward- and one in upward looking mode, reveal extensive but scattered single bubble releases rather than distinct and more continuous sources. While these releases are difficult to detect in forward looking mode, they can unambiguously be detected in the upward looking mode even for minor gas releases, bubble rising speeds can be determined. Greinert, J., 2008. Monitoring temporal variability of bubble release at seeps: The hydroacoustic swath system GasQuant. J. Geophys. Res. Oceans Vol. 113 Issue C7 CiteID C07048 113, 7048. doi:10.1029/2007JC004704 Schneider von Deimling, J., Greinert, J., Chapman, N.R., Rabbel, W., Linke, P., 2010. Acoustic imaging of natural gas seepage in the North Sea: Sensing bubbles controlled by variable currents. Limnol. Oceanogr. Methods 8, 155. doi:10.4319/lom.2010.8.155

  17. A simple and rapid gas chromatographic method for the determination of dissolved deuterium and nitrogen in heavy water coolant of a nuclear reactor

    International Nuclear Information System (INIS)

    Nair, B.K.S.

    1976-01-01

    A known volume of a heavy water sample is equilibrated with a known volume of pure helium gas at atmospheric pressure in a sample tube. The dissolved gases evolve into the helium and distribute themselves between the gaseous and liquid phases according to their equilibrium partial pressures. These partial pressures of the gases in the equilibrium gas mixture are determined by analysing it gas-chromatographically. From these analytical data and the absorption coefficients of deuterium and nitrogen, their original concentrations in heavy water are calculated. Corrections for the increase in the total pressure of the gaseous phase owing to evolved gases are calculated and found to be negligible. Air contamination during sampling and analysis can be detected by the presence of the oxygen peak in the chromatogram and corrected for. The calculation is facilitated by programming it on an electronic calculator. The method is much simpler and faster than the vacuum method usually applied for this analysis. One determination can be completed in about an hour. The average deviation and standard deviation have been estimated at 0.19 ml/litre heavy water and 0.25 ml/litre heavy water respectively in deuterium, and 0.36 and 0.68 ml/litre in nitrogen. (author)

  18. Towards the inclusion of open fabrication porosity in a fission gas release model

    Energy Technology Data Exchange (ETDEWEB)

    Claisse, Antoine, E-mail: claisse@kth.se [KTH Royal Institute of Technology, Reactor Physics, AlbaNova University Centre, 106 91, Stockholm (Sweden); Van Uffelen, Paul [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125, Karlsruhe (Germany)

    2015-11-15

    A model is proposed for fission product release in oxide fuels that takes into account the open porosity in a mechanistic manner. Its mathematical framework, assumptions and limitations are presented. It is based on the model for open porosity in the sintering process of crystalline solids. More precisely, a grain is represented by a tetrakaidecahedron and the open porosity is represented by a continuous cylinder along the grain edges. It has been integrated in the TRANSURANUS fuel performance code and applied to the first case of the first FUMEX project as well as to neptunium and americium containing pins irradiated during the SUPERFACT experiment and in the JOYO reactor. The results for LWR and FBR fuels are consistent with the experimental data and the predictions of previous empirical models when the thermal mechanisms are the main drivers of the release, even without using a fitting parameter. They also show a different but somewhat expected behaviour when very high porosity fuels are irradiated at a very low burn-up and at low temperature. - Highlights: • We developed a new athermal FGR model based on the porosity. • We present the model, its framework, assumptions and limitations. • We test it out on several irradiation experiments. • Results are comparable to previous models but without using an empirical parameter.

  19. Fission gas release behavior of MOX fuels under simulated daily-load-follow operation condition. IFA-554/555 test evaluation with FASTGRASS code

    International Nuclear Information System (INIS)

    Ikusawa, Yoshihisa; Ozawa, Takayuki

    2008-03-01

    IFA-554/555 load-follow tests were performed in HALDEN reactor (HBWR) to study the MOX fuel behavior under the daily-load-follow operation condition in the framework of ATR-MOX fuel development in JAEA. IFA-554/555 rig had the instruments of rod inner pressure, fuel center temperature, fuel stack elongation, and cladding elongation. Although the daily-load-follow operation in nuclear power plant is one of the available options for economical improvement, the power change in a short period in this operation causes the change of thermal and mechanical irradiation conditions. In this report, FP gas release behavior of MOX fuel rod was evaluated under the daily-load-follow operation condition with the examination data from IFA-554/555 by using the computation code 'FASTGRASS'. From the computation results of FASTGRASS code which could compute the FP gas release behavior under the transient condition, it could be concluded that FP gas was released due to the relaxation of fuel pellet inner stress and pellet temperature increase, which were caused by the cyclic power change during the daily-load-follow operation. In addition, since the amount of released FP gas decreased during the steady operation after the daily-load-follow, it could be mentioned that the total of FP gas release at the end of life with the daily-load-follow is not so much different from that without the daily-load-follow. (author)

  20. Gas-phase spectroscopic studies of heavy elements compounds (group V) using FTIR technique

    International Nuclear Information System (INIS)

    Allaf, A. W.; Ajji, Z.

    1998-12-01

    Antimony oxide trihalide, OSbX3 where X=F, CI and Br, and antimony (III) oxychloride, OSbC1 molecules were produced by an on-line process for the first time using antimony chloride SbC13 passed over heated silver oxide then followed by passing the obtained products over heated NaF and heated KBr for SbOF3 and OSbBr3, respectively. The obtained OSbC13 reacts with heated silver to produce OSbC1. The products have been characterized by the infrared spectra of their vapors. The low resolution gas-phase Fourier transform infrared spectrum, reported for the first time, shows the most characteristic band of OSbX3 at 1272, 1217 and 1200 cm -1 and the bands are assigned to the O=Sb stretching fundamental of OSbX3 were X=F, Cl and Br, respectively. The band at 1200 cm -1 needs more experimental investigation. The band at 924 cm -1 is assigned to the O=Sb stretching fundamental of OSbCl molecule. This result is in consistent with expectation and shifted to lower frequency in comparison with arsenic analogous molecule which is investigated by matrix-isolation technique. The work will be continued in order to cover the bismuth and arsenic compounds of similar structures. (author)

  1. Gas release from a failed fuel pin after reactor shut-down

    International Nuclear Information System (INIS)

    Pshenichnikov, B.V.

    1975-01-01

    A mathematical model of gassing from a hypothetical core fuel element in the active zone of a stopped water-moderated reactor was analysed to investigate the process of liberation of gaseous fission products from an unpressurized fuel element. A one-dimensional problem was obtained as a result of the accepted hypotheses. A fault was assumed to have occured during reactor operation; at the same time, a vapour-gas mixture was considered to be present under the envelope at reactor working pressure by the moment of stoppage. An approximative estimation was made of the retardation time of pressure balancing at the open end of the fuel element, and also of the amount of total gas remaining in the gap under the fuel element envelope after pressure drop in the reactor. Estimation of retardation time permitted to conclude that pressure in the nonhermetic fuel element envelope follows pressure fluctuation in the reactor in the course of cooling, the retardation time of pressure balancing outside and inside the fuel element lasting but a few seconds

  2. Access pricing on gas networks and capacity release markets: Lessons from North American and European experiences

    International Nuclear Information System (INIS)

    David, L.; Percebois, J.

    2004-01-01

    An evaluation of different access fee systems in North America and Europe in relation to normative prices is discussed. Among available alternatives the entry-exit pricing system as it is currently applied in the United Kingdom, the Netherlands, Italy and France, was judged to be the best solution to increased competition. Canadian and American experiences highlight the influence of the market power of shippers with regard to the efficacy of capping the market. Whether or not to cap the price on a capacity release market is a choice between the protection of shippers against market abuses and the promotion of secondary market liquidity, a choice that is linked to the level of congestion of a pipeline system. If there is much congestion, a price cap may be necessary; if there is little congestion, the need for market value given by an uncapped price may be more important than the market power of shippers. 15 refs., 2 tabs

  3. Total Particle Number Emissions from Modern Diesel, Natural Gas, and Hybrid Heavy-Duty Vehicles During On-Road Operation.

    Science.gov (United States)

    Wang, Tianyang; Quiros, David C; Thiruvengadam, Arvind; Pradhan, Saroj; Hu, Shaohua; Huai, Tao; Lee, Eon S; Zhu, Yifang

    2017-06-20

    Particle emissions from heavy-duty vehicles (HDVs) have significant environmental and public health impacts. This study measured total particle number emission factors (PNEFs) from six newly certified HDVs powered by diesel and compressed natural gas totaling over 6800 miles of on-road operation in California. Distance-, fuel- and work-based PNEFs were calculated for each vehicle. Distance-based PNEFs of vehicles equipped with original equipment manufacturer (OEM) diesel particulate filters (DPFs) in this study have decreased by 355-3200 times compared to a previous retrofit DPF dynamometer study. Fuel-based PNEFs were consistent with previous studies measuring plume exhaust in the ambient air. Meanwhile, on-road PNEF shows route and technology dependence. For vehicles with OEM DPFs and Selective Catalytic Reduction Systems, PNEFs under highway driving (i.e., 3.34 × 10 12 to 2.29 × 10 13 particles/mile) were larger than those measured on urban and drayage routes (i.e., 5.06 × 10 11 to 1.31 × 10 13 particles/mile). This is likely because a significant amount of nucleation mode volatile particles were formed when the DPF outlet temperature reached a critical value, usually over 310 °C, which was commonly achieved when vehicle speed sustained over 45 mph. A model year 2013 diesel HDV produced approximately 10 times higher PNEFs during DPF active regeneration events than nonactive regeneration.

  4. Gas chromatographic sulphur speciation in heavy crude oil using a modified standard D5623 method and microfluidic Deans switching.

    Science.gov (United States)

    Heshka, Nicole E; Choy, Joanne M; Chen, Jinwen

    2017-12-29

    A modification to American Society for Testing and Materials (ASTM) method D5623 is proposed to enable successful and repeatable analysis of heavy crude oil samples. A two-dimensional gas chromatography configuration was implemented, with separation of sulphur compounds occurring on two columns. A Deans switch is used to enable heart-cutting of volatile sulphur compounds onto a DB-Sulfur stationary phase, and separation occurs concurrently with the backflushing of the primary column. The use of a sulphur-selective detector increases selectivity, and 22 volatile sulphur species are quantified in less than 15min, which is almost half the time of the original ASTM method. Samples ranging from light distillation cuts to whole crudes (boiling from 100°C to >750°C) were analyzed with minimal sample preparation. The calculated limit of detection was 0.7mg/kg, repeatability was 3% relative standard deviation (RSD), and a linear range of 1-250mg/kg was obtained, with an R 2 value of 0.994 or better, depending on the compound. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  5. N2 O A greenhouse gas released from the combustion of coals in fluidized beds

    International Nuclear Information System (INIS)

    Boavida, D.; Lobo, L. S.; Gulyurtlu, I.; Cabrita, I.

    1996-01-01

    This paper discusses the results of the experimental work investigating the formation of N-2 O and NO during fluidized bed combustion of coals, and of chars and volatiles produced from the pyrolysis of these coals. Ammonia (N H 3 ) and hydrogen cyanide (HCN) are shown to play important roles as gas phase precursors of both NO and N 2 O. The conversion of fuel-N through N H 3 and HCN to N 2 O and NO was studied using a fluidized bed combustor in the temperature range between 973 K and 1273 K, for two different coals. The results suggest that the principal contribution to N 2 O emission Originated from volatile-N, however, char-N could also have an important role, depending upon the temperature. 1 fig., 8 tabs

  6. EDO, Doses to Man and Organs from Reactor Operation Noble Gas and Liquid Waste Release

    International Nuclear Information System (INIS)

    Rodenas Diago, Jose; Serradell Garcia, Vicente

    1983-01-01

    1 - Description of problem or function: EDO evaluates individual and collective doses to man from atmospheric releases of noble gases and other gaseous effluents. 2 - Method of solution: The dose calculations are carried out by following the guide- lines of USNRC Regulatory Guide 1.109. Radiation exposure for maximum individuals and population are estimated within 30 km from the nuclear plant. This area is divided into 160 circular trapezoids, to which computations are referred. Four age groups, seven organs for internal dose and two for external dose have been considered. Dose calculations are done through 14 pathways, 7 for liquid effluents, one for noble gases, and 6 for the rest of gaseous effluents. 3 - Restrictions on the complexity of the problem: The following are the maximum dimension sizes preset in the code: 73 radionuclides (other than noble gases); 15 noble gases; 160 circular trapezoids; 31 chemical elements; 4 types of aquatic foods; 15 points of exposure for shorelines; 15 trapezoids influenced by each point; 4 terrestrial food pathways; 100 centres of population. Some of these limits can be varied

  7. EDO, Doses to Man and Organs from Reactor Operation Noble Gas and Liquid Waste Release

    Energy Technology Data Exchange (ETDEWEB)

    Rodenas Diago, Jose; Serradell Garcia, Vicente [Departamento de Ingenieria Nuclear, Escuela Tecnica Superior de Ingenieros Industriales, Universidad Politecnica, Camino de Vera 2/n Apartado 2012, Valencia (Spain)

    1983-10-18

    1 - Description of problem or function: EDO evaluates individual and collective doses to man from atmospheric releases of noble gases and other gaseous effluents. 2 - Method of solution: The dose calculations are carried out by following the guide- lines of USNRC Regulatory Guide 1.109. Radiation exposure for maximum individuals and population are estimated within 30 km from the nuclear plant. This area is divided into 160 circular trapezoids, to which computations are referred. Four age groups, seven organs for internal dose and two for external dose have been considered. Dose calculations are done through 14 pathways, 7 for liquid effluents, one for noble gases, and 6 for the rest of gaseous effluents. 3 - Restrictions on the complexity of the problem: The following are the maximum dimension sizes preset in the code: 73 radionuclides (other than noble gases); 15 noble gases; 160 circular trapezoids; 31 chemical elements; 4 types of aquatic foods; 15 points of exposure for shorelines; 15 trapezoids influenced by each point; 4 terrestrial food pathways; 100 centres of population. Some of these limits can be varied.

  8. Screening of inorganic gases released from firework-rockets by a gas chromatography/whistle-accelerometer method.

    Science.gov (United States)

    Chen, Kuan-Fu; Wu, Hui-Hsin; Lin, Chien-Hung; Lin, Cheng-Huang

    2013-08-30

    The use of an accelerometer for detecting inorganic gases in gas chromatography (GC) is described. A milli-whistle was connected to the outlet of the GC capillary and was used instead of a classical GC detector. When the GC carrier gases and the sample gases pass through the milli-whistle, a sound is produced, leading to vibrational changes, which can be recorded using an accelerometer. Inorganic gases, including SO2, N2 and CO2, which are released from traditional Chinese firework-rockets at relatively high levels as the result of burning the propellant and explosive material inside could be rapidly determined using the GC/whistle-accelerometer system. The method described herein is safe, the instrumentation is compact and has potential to be modified so as to be portable for use in the field. It also can be used in conjunction with FID (flame ionization detector) or TCD (thermal conductivity detector), in which either no response for FID (CO2, N2, NO2, SO2, etc.) or helium gas is needed for TCD, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Development of a code to simulate dispersion of atmospheric released tritium gas in the environmental media and to evaluate doses. TRIDOSE

    International Nuclear Information System (INIS)

    Murata, Mikio; Noguchi, Hiroshi; Yokoyama, Sumi

    2000-11-01

    A computer code (TRIDOSE) was developed to assess the environmental impact of atmospheric released tritium gas (T 2 ) from nuclear fusion related facilities. The TRIDOSE simulates dispersion of T 2 and resultant HTO in the atmosphere, land, plant, water and foods in the environment, and evaluates contamination concentrations in the media and exposure doses. A part of the mathematical models in TRIDOSE were verified by comparison of the calculation with the results of the short range (400 m) dispersion experiment of HT gas performed in Canada postulating a short-time (30 minutes) accidental release. (author)

  10. Development of a code to simulate dispersion of atmospheric released tritium gas in the environmental media and to evaluate doses. TRIDOSE

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Mikio [Nuclear Engineering Co., Ltd., Hitachi, Ibaraki (Japan); Noguchi, Hiroshi; Yokoyama, Sumi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-11-01

    A computer code (TRIDOSE) was developed to assess the environmental impact of atmospheric released tritium gas (T{sub 2}) from nuclear fusion related facilities. The TRIDOSE simulates dispersion of T{sub 2} and resultant HTO in the atmosphere, land, plant, water and foods in the environment, and evaluates contamination concentrations in the media and exposure doses. A part of the mathematical models in TRIDOSE were verified by comparison of the calculation with the results of the short range (400 m) dispersion experiment of HT gas performed in Canada postulating a short-time (30 minutes) accidental release. (author)

  11. Impact of production and release of gas in a L/ILW repository. A summary of the work performed within the Nagra programme

    International Nuclear Information System (INIS)

    Zuidema, P.; Hoglund, L.O.

    1988-01-01

    In a repository for low- and intermediate-level radioactive wastes, gases will be formed due to corrosion of metals, microbial degradation of organic materials and radiolytic decomposition of water and organic materials. The predominant source of gas is calculated to be anaerobic corrosion of metals, particularly iron. Gas pressure will build up in the near-field until it is released through the system of engineered barriers into the geosphere at a rate equivalent to the production rate. Excessive gas pressures may damage the engineered barriers if no precautions are taken. Radionuclide transport both through the host rock and near-field may be influenced by such gas releases. Water will be displaced and local hydrology will be altered. The significance of these alterations are site-specific; theoretical studies as well as field investigations are underway to clarify the role of the different processes involved

  12. Geochemical evidence of water-soluble gas accumulation in the Weiyuan gas field, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Shengfei Qin

    2016-01-01

    Full Text Available At present, there are several different opinions on the formation process of the Weiyuan gas field in the Sichuan Basin and the source of its natural gas. In view of the fact that the methane carbon isotope of the natural gas in the Weiyuan gas field is abnormally heavy, the geologic characteristics of gas reservoirs and the geochemical characteristics of natural gas were first analyzed. In the Weiyuan gas field, the principal gas reservoirs belong to Sinian Dengying Fm. The natural gas is mainly composed of methane, with slight ethane and trace propane. The gas reservoirs are higher in water saturation, with well preserved primary water. Then, it was discriminated from the relationship of H2S content vs. methane carbon isotope that the heavier methane carbon isotope of natural gas in this area is not caused by thermochemical sulfate reduction (TSR. Based on the comparison of methane carbon isotope in this area with that in adjacent areas, and combined with the tectonic evolution background, it is regarded that the natural gas in the Weiyuan gas field is mainly derived from water-soluble gas rather than be migrated laterally from adjacent areas. Some conclusions are made. First, since methane released from water is carbon isotopically heavier, the water-soluble gas accumulation after degasification results in the heavy methane carbon isotope of the gas produced from Weiyuan gas field. Second, along with Himalayan movement, great uplift occurred in the Weiyuan area and structural traps were formed. Under high temperature and high pressure, the gas dissolved in water experienced decompression precipitation, and the released natural gas accumulated in traps, consequently leading to the formation of Weiyuan gas field. Third, based on calculation, the amount of natural gas released from water which is entrapped in the Weiyuan gas field after the tectonic uplift is basically equal to the proved reserves of this field, confirming the opinion of water

  13. Waste isolation pilot plant performance assessment: Radionuclide release sensitivity to diminished brine and gas flows to/from transuranic waste disposal areas

    Energy Technology Data Exchange (ETDEWEB)

    Day, Brad A.; Camphouse, R. C.; Zeitler, Todd R. [Sandia National Laboratories, Carlsbad (United States)

    2017-03-15

    Waste Isolation Pilot Plant repository releases are evaluated through the application of modified parameters to simulate accelerated creep closure, include capillary pressure effects on relative permeability, and increase brine and gas saturation in the operations and experimental (OPS/EXP) areas. The modifications to the repository model result in increased pressures and decreased brine saturations in waste areas and increased pressures and brine saturations in the OPS/EXP areas. Brine flows up the borehole during a hypothetical drilling intrusion are nearly identical and brine flows up the shaft are decreased. The modified parameters essentially halt the flow of gas from the southern waste areas to the northern nonwaste areas, except as transported through the marker beds and anhydrite layers. The combination of slightly increased waste region pressures and very slightly decreased brine saturations result in a modest increase in spallings and no significant effect on direct brine releases, with total releases from the Culebra and cutting and caving releases unaffected. Overall, the effects on total high-probability mean releases from the repository are insignificant, with total low-probability mean releases minimally increased. It is concluded that the modified OPS/EXP area parameters have an insignificant effect on the prediction of total releases.

  14. Effects of mining activities on the release of heavy metals(HMs) in the head water regions of the Heihe River.

    Science.gov (United States)

    Wei, W., Sr.; Ma, R.; Sun, Z.; Bu, J.; Chang, Q.

    2017-12-01

    The head water regions of Heihe River were located in the Qilian orogenic belt, where belongs to the Qilian Mountains National Ecological Nature Protection and has fragile ecosystem. Previous surveys show that the regions were rich in various metal ores, and the mining activities have been intense.The environmental effect of mining activities will be going on several years, while Our field investigation show that there were 23 mines, of which 18 have been historical. This study collected water samples in main Heihe river and its tributaries, groundwaters and soil water, and the sediment samples near the ores. The concentration of HMs in both waters and sediments was measured for characterizing the spatial distribution of HMs, and determining the origin of the HMs in the river waters. Results of water quality assessment show that 67% of water samples failed to reach the Grade II environmental quality standard for surface water in China (GB3838-2002).The spatial distribution of HMs (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) is highly correlated with the geographical distribution of local mines, suggesting that various heavy metals(HMs) were released into the Heihe River via mining activities. The Be, Co, Sn, Bi, Th, U were mainly derived from aluminosilicate weathering crusts. And the acid mine wastewater was the main source for Cu, Zn, Pb, Cd. The Serpentine wreathing was the main source for Cr and Ni. Mn and Cs were enriched by agricultural activities.

  15. The influence of the structural characteristics of polyethylene on the release of gas mixtures for extrusion processing

    Directory of Open Access Journals (Sweden)

    V. I. Korchagin

    2017-01-01

    Full Text Available The study of thermal and mechano-thermal effects in the inert and air environment on the evolution of gas formations from high pressure polyethylene (LDPE was carried out on a Smart RHEO 1000 capillary rheometer with the CeastView 5.94.4D software, using capillaries 5 mm in length and 1 mm in diameter . Study of composition Gas formations during the deformation of polyethylenes of different grades through the channel of a capillary viscometer. Which were characterized by structural characteristics, were carried out at shear rates close to production in the range from 50 to 300 s-1 at temperatures of 160, 190 and 220 ° C. The objects of the study were domestic thermoplastics of the following brands: LDPE 10803-020; LDPE 15803020; LPVD F-03020-S; HDPE 293-285-D, characterized by structural characteristics. It is established that the gasification during extrusion processing is promoted by the branching of polyethylene, while the degree of destruction processes increases with increasing temperature and depends on the reaction medium of the working volume of the equipment. Emerging critical shear stresses in the absence of oxidants and impurities contribute to mechano-destruction, accompanied by the formation of free radicals, which recombine to form a more branched structure of the polymer. In turn, the high temperature promotes degradation in the side parts of the polymer to form volatile products that are released from the reaction volume. It should be noted that the gassing due to thermal exposure is promoted by the air environment, but to a lesser extent than with mechano-thermal action. A smaller measure of the impact in the inertial medium is apparently associated with a limited access of oxidants to the destruction centers.

  16. A prediction of the UO2 fission gas release data of Bellamy and Rich using a model recently developed by combustion engineering

    International Nuclear Information System (INIS)

    Freeburn, H.R.; Pati, S.R.

    1983-01-01

    The trend in the Light Water Reactor industry to higher discharge burnups of UO 2 fuel rods has initiated the modification of existing fuel rod models to better account for high burnup effects. A model recently developed by Combustion Engineering, Inc. (C-E) for fission gas release from UO 2 fuel recognizes the separate effects of temperature-dependent and temperature-independent release mechanisms. This model accounts for a moderate burnup enhancement that is based on a concept of a saturation inventory existing for the intra- and inter-grannular storage of fission gas within the fuel pellet. The saturation inventory, as modelled, is strongly dependent on the local temperature and the changing grain size of the fuel with burnup. Although the fitting constants of the model were determined solely from more current gas release data from fuel more typical of the C-E product line, the model, nonetheless, provides an excellent prediction of the Bellamy and Rich data over the entire burnup range represented by the data (+-1.6% gas release at a 1σ level). The ability to obtain a good comparison with this data base provides additional support for the use of the particular separation of the effects of thermal diffusion and burnup enhancement on fission gas release that is embodied in the model. Furthermore, the degree of burnup enhancement in the model is believed to be moderate enough to suggest that this high burnup effect should not impede the extension of discharge burnup limits associated with current design fuel rods for Pressurized Water Reactors

  17. Steady-State Flammable Gas Release Rate Calculation And Lower Flammability Level Evaluation For Hanford Tank Waste

    International Nuclear Information System (INIS)

    Meacham, J.E.

    2008-01-01

    This report assesses the steady state flammability level under off normal ventilation conditions in the tank headspace for 28 double-shell tanks (DST) and 149 single shell-tanks (SST) at the Hanford Site. Flammability was calculated using estimated gas release rates, Le Chatelier's rule, and lower flammability limits of fuels in an air mixture. This revision updates the hydrogen generation rate input data for al1 177 tanks using waste composition information from the Best Basis Inventory Detail Report (data effective as of August 4,2008). Assuming only barometric breathing, the shortest time to reach 25% of the lower flammability limit is 13 days for DSTs (i.e., tank 241-AZ-102) and 36 days for SSTs (i.e., tank 241-B-203). Assuming zero ventilation, the shortest time to reach 25% of the lower flammability limit is 12 days for DSTs (i.e., tank 241-AZ-102) and 34 days for SSTs (i.e., tank 241-B-203).

  18. Steady-State Flammable Gas Release Rate Calculation And Lower Flammability Level Evaluation For Hanford Tank Waste

    International Nuclear Information System (INIS)

    Meacham, J.E.

    2009-01-01

    This report assesses the steady state flammability level under off normal ventilation conditions in the tank headspace for 28 double-shell tanks (DST) and 149 single shell-tanks (SST) at the Hanford Site. Flammability was calculated using estimated gas release rates, Le Chatelier's rule, and lower flammability limits of fuels in an air mixture. This revision updates the hydrogen generation rate input data for all 177 tanks using waste composition information from the Best Basis Inventory Detail Report (data effective as of August 4,2008). Assuming only barometric breathing, the shortest time to reach 25% of the lower flammability limit is 11 days for DSTs (i.e., tank 241-AZ-10l) and 36 days for SSTs (i.e., tank 241-B-203). Assuming zero ventilation, the shortest time to reach 25% of the lower flammability limit is 10 days for DSTs (i.e., tank 241-AZ-101) and 34 days for SSTs (i.e., tank 241-B-203).

  19. Equation of state for L.M.F.B.R. fuel (measurement of fission gas release during transients)

    International Nuclear Information System (INIS)

    Combette, P.; Barthelemy, P.

    1979-01-01

    A sample of fuel (UO 2 or UPuO 2 ) can be heated by fission in a heating transient up to energy deposition 4000 j/g, in the Silene reactor. The Kistler type capsule, the calorimeter device and the radiochemical analysis of fission products enable the pressure pulse and the fuel energy deposition to be measured. So, the relationship between the fuel vapour pressure and the fuel specific energy can be deduced. Peaks pressure (about 1 MPa) coming from fresh UO 2 vaporization, have been measured on a 7 milliseconds time scale. There is a good agreement with the E.O.S. for fresh UO 2 , which is well known for low pressure (1 MPa). Numerous tests have been done with 93% enriched UO 2 and a first test with highly active fuel containing plutonium (15 at %) has been performed. The capsule allows the released gas coming from the irradiated fuel to be retained for measurements and analysis. To investigate the mode of fuel disruption, in-pile fission-heated fuel pellets has been recorded by high speed cinematography

  20. Assessments of sheath strain and fission gas release data from 20 years of power reactor fuel irradiations

    International Nuclear Information System (INIS)

    Purdy, P.L.; Manzer, A.M.; Hu, R.H.; Gibb, R.A.; Kohn, E.

    1997-01-01

    Over the past 20 years, many fuel elements or bundles discharged from Canadian CANDU power reactors have been examined in the AECL hot cells. The post-irradiation examination (PIE) database covers a wide range of operating conditions, from which fuel performance characteristics can be assessed. In the present analysis, a PIE database was compiled representing elements from a total of 129 fuel bundles, of which 26% (34 bundles) were confirmed to have one or more defective elements. This comprehensive database was assessed in terms of measured sheath strain and fission gas release (FGR) for intact elements, in an attempt to identify any changes in these parameters over the history of CANDU reactor operation. Results from this assessment indicate that, for the data that are typical of normal CANDU operating conditions, tensile sheath strain and FGR have remained within 0.5% and 8%, respectively. Those data beyond these ranges are from fuel operated under abnormal conditions, not representative of normal operation, and thus do not indicate a trend toward unexpected fuel behaviour. The distributions of the PIE measurements indicate that maximum expected sheath strains and FGR for normally operated fuel are 0.7% and 13%, respectively. (author)

  1. Characterization of the gas releasing behaviors of catalytic pyrolysis of rice husk using potassium over a micro-fluidized bed reactor

    International Nuclear Information System (INIS)

    Liu, Yuan; Wang, Yan; Guo, Feiqiang; Li, Xiaolei; Li, Tiantao; Guo, Chenglong; Chang, Jiafu

    2017-01-01

    Highlights: • Releasing propensity of CO, CO 2 , CH 4 and H 2 was studied in a micro-fluidized bed. • Gas releasing pattern was influenced by temperature and potassium concentration. • Variations in gas forming E a are indicative of catalytic performance of potassium. - Abstract: Influence of potassium on the gas releasing behaviors during rice husk high-temperature pyrolysis was investigated under isothermal conditions in a two stage micro-fluidized bed reactor. Reaction kinetics for generating H 2 , CO, CO 2 and CH 4 was investigated based on the Friedman and model-fitting approaches. Results indicated that different gas species had different times to start and end the gas release process, particularly at 600 °C, representing different chemical routes and mechanics for generating these gas components. The resulting apparent activation energies for H 2 , CO, and CO 2 decreased from 23.10 to 12.00 kJ/mol, 15.48 to 14.03 kJ/mol and 10.14 to 7.61 kJ/mol respectively with an increase in potassium concentration from 0 to 0.5 mol/kg, while that for CH 4 increased from 16.85 to 19.40 kJ/mol. The results indicated that the addition of potassium could promote the generation reactions of H 2 , CO and CO 2 while hinder the generation reactions of CH 4 . The pyrolysis reaction was further found to be subject to the three-dimensional diffusion model for all the samples.

  2. Adsorption by and artificial release of zinc and lead from porous concrete for recycling of adsorbed zinc and lead and of porous concrete to reduce urban non-point heavy metal runoff.

    Science.gov (United States)

    Harada, Shigeki; Yanbe, Miyu

    2018-04-01

    This report describes the use of porous concrete at the bottom of a sewage trap to prevent runoff of non-point heavy metals into receiving waters, and, secondarily, to reduce total runoff volume during heavy rains in urbanized areas while simultaneously increasing the recharge volume of heavy-metal-free water into underground aquifers. This idea has the advantage of preventing clogging, which is fundamentally very important when using pervious materials. During actual field experiments, two important parameters were identified: maximum adsorption weight of lead and zinc by the volume of porous concrete, and heavy metal recovery rate by artificial acidification after adsorption. To understand the effect of ambient heavy metal concentration, a simple mixing system was used to adjust the concentrations of lead and zinc solutions. The concrete blocks used had been prepared for a previous study by Harada & Komuro (2010). The results showed that maximum adsorption depended on the ambient concentration, expressed as the linear isothermal theory, and that recovery depended on the final pH value (0.5 or 0.0). The dependence on pH is very important for recycling the porous concrete. A pH of 0.5 is important for recycling both heavy metals, especially zinc, (8.0-22.1% of lead and 42-74% of zinc) and porous concrete because porous concrete has not been heavily damaged by acid. However, at a pH of 0.0, the heavy metals could be recovered: 30-60% of the lead and 75-125% of the zinc. At a higher pH, such as 2.0, no release of heavy metals occurred, indicating the safety to the environment of using porous concrete, because the lowest recorded pH of rainfall in Japan is. 4.0. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. ERCB investigation report : Daylight Energy Amalgamation Co Ltd. sour gas release surface location 06-23-047-10W5M December 16, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Temple, B.; Schlager, J.; Wilkes, J.; Saulnier, P.; Mayall, J.; Duben, A.; Ravensdale, C.

    2010-07-21

    This report discussed a sour gas release that occurred at a well located near the town of Lodgepole. The well had a hydrogen sulfide (H{sub 2}S) concentration of 29.19 per cent, with an emergency planning zone (EPZ) of 570 m. The owner of the well contacted stakeholders in the region, and road blocks were set up north of the well. Three mobile air monitoring units were dispatched to the site, and service contractors were hired to kill the well. The road blocks were removed after a review of the air monitoring data. Prior to the release, a heat tape assembly had been installed in the well as a result of ongoing hydrate formation problems. An investigation of the well after the release showed damage to the connectors in the heat tape assembly. A failure analysis showed that the damage was caused by excessive temperatures created by a short circuit in the wires located in each connector. The heat allowed downhole gas pressure to push the wire to the surface. Gas was released from the damaged assembly seal. An outline of all steps taken to address the emergency was provided. 4 figs.

  4. The evaluation of failure stress and released amount of fission product gas of power ramped rod by fuel behaviour analysis code 'FEMAXI-III'

    International Nuclear Information System (INIS)

    Yanagisawa, Kazuaki; Fujita, Misao

    1984-01-01

    Pellet-Cladding Interaction(PCI) related in-pile failure of Zircaloy sheathed fuel rod is in general considered to be caused by combination of pellet-cladding mechanical interaction(PCMI) with fuel-cladding chemical interaction(FCCI). An understanding of a basic mechanism of PCI-related fuel failure is therefore necessary to get actual cladding hoop stress from mechanical interaction and released amounts of fission product(FP) gas of aggressive environmental agency from chemical interaction. This paper describes results of code analysis performed on fuel failure to cladding hoop stress and amounts of FP gas released under the condition associated with power ramping. Data from Halden(HBWR) and from Studsvik(R2) are used for code analysis. The fuel behaviour analysis code ''FEMAXI-III'' is used as an analytical tool. The followings are revealed from the study: (1) PCI-related fuel failure is dependent upon cladding hoop stress and released amounts of FP gas at power ramping. (2) Preliminary calculated threshold values of hoop stress and of released amounts of FP gas to PCI failure are respectively 330MPa, 10% under the Halden condition, 190MPa, 5% under the Inter ramp(BWR) condition, and 270MPa, 14% under the Over ramp(PWR) condition. The values of hoop stress calculated are almost in the similar range of those obtained from ex-reactor PCI simulated tests searched from references published. (3) The FEMAXI-III code verification is made in mechanical manner by using in-pile deformation data(diametral strain) obtained from power ramping test undertaken by JAERI. While, the code verification is made in thermal manner by using punctured FP gas data obtained from post irradiation examination performed on non-defected power ramped fuel rods. The calculations are resulted in good agreements to both, mechanical and thermal experimental data suggesting the validity of the code evaluation. (J.P.N.)

  5. Fission gas release behaviour of a 103 GWd/t{sub HM} fuel disc during a 1200 °C annealing test

    Energy Technology Data Exchange (ETDEWEB)

    Noirot, J., E-mail: jean.noirot@cea.fr [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Pontillon, Y. [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Yagnik, S. [EPRI, P.O. Box 10412, Palo Alto, CA 94303-0813 (United States); Turnbull, J.A. [Independent Consultant (United Kingdom); Tverberg, T. [IFE, P.O. Box 173, NO-1751 Halden (Norway)

    2014-03-15

    Within the Nuclear Fuel Industry Research (NFIR) program, several fuel variants, in the form of thin circular discs, were irradiated in the Halden Boiling Water Reactor (HBWR) to a range of burn-ups ∼100 GWd/t{sub HM}. The design of the assembly was similar to that used in other HBWR programs: the assembly contained several rods with fuel discs sandwiched between Mo discs, which limited temperature gradients within the fuel discs. One such rod contained standard grain UO{sub 2} discs (3D grain size = 18 μm) reaching a burn-up of 103 GWd/t{sub HM}. After the irradiation, the gas release upon rod puncturing was measured to be 2.9%. Detailed characterizations of one of these irradiated UO{sub 2} discs, using electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS), were performed in a CEA Cadarache hot laboratory. Examination revealed the high burn-up structure (HBS) formation throughout the whole of the disc, also the fission gas distribution within this HBS, with a very high proportion of the gas in the HBS bubbles. A sibling disc was submitted to a temperature transient up to 1200 °C in the out-of-pile (OOP) annealing test device “Merarg” at a relatively low temperature ramp rate (0.2 °C/s). In addition to the total gas release during this annealing test, the release peaks throughout the temperature range were monitored. The fuel was then characterized with the same microanalysis techniques as before the annealing test to investigate the effects of this test on the microstructure of the fuel and on the fission gases. It provided valuable insights into fission gas localization and the release behaviour in UO{sub 2} fuel with high burn-up structure (HBS)

  6. The stability of CaS in circulating fluidized bed boiler residue and the possible release of H2S gas to the atmosphere

    International Nuclear Information System (INIS)

    Mattisson, T.; Lyngfelt, A.

    1995-01-01

    During the combustion of coal, SO 2 is released to the atmosphere. Because of environmental concerns with acid rain, the capture of SO 2 is an important issue. In fluidized bed combustion SO 2 is captured in-situ by limestone or dolomite to form CaSO 4 . This product is stable and can be disposed of or reused as gypsum. In order to capture the sulphur as CaSO 4 oxidizing conditions are necessary. In a fluidized bed boiler (FBB) CaS may form in regions with reducing conditions, and FBB ashes sampled under irregular operating conditions may contain as much as 50 % of the captured sulphur as CaS. The stability of CaS in a landfill environment is thus very important. It is possible that the sulphide decomposes in the presence of moisture or runoff leachate with the subsequent release of H 2 S gas. This re-release of captured sulphur could have a substantial effect on the overall sulphur capture efficiency, with more sulphur released to the atmosphere than previously thought. In this study the stability of CaS in bed ashes from a 12 MW circulating FBB combusting coal has been investigated, with focus on the release of H 2 S gas. (orig.)

  7. Hydrodenitrogenation and hydrodesulphurization of heavy gas oil using NiMo/Al{sub 2}O{sub 3} catalyst containing phosphorous : experimental and kinetic studies

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Dalai, A.K. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering; Adjaye, J. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

    2005-10-01

    Oil sand bitumens and their derived products contain high levels of nitrogen and sulfur compounds which cause the formation of SOx and NOx in the atmosphere. These compounds also deactivate the catalysts used in fluid catalytic cracking and hydrocracking. This study focused on finding a better catalyst to efficiently remove sulphur and nitrogen from oil sand-derived heavy gas oils. The NiMo/Al{sub 2}O{sub 3} catalyst with phosphorous (P) was used in a trickle-bed reactor under a range of temperature and pressure conditions to study the reactivity of vacuum, atmospheric and hydrocracked heavy gas oils produced from Athabasca bitumen. The concentration of phosphorous was maintained at 2.7 wt per cent, while the hydrogen flow rate and catalyst weight were maintained constant at 50 mL/min and 4 g respectively. An ANOVA analysis of experimental data was performed to optimize the process conditions for hydrodenitrogenation (HDN) and hydrodesulphurization (HDS) reactions. Kinetic studies for HDN and HDS reactions were studied within the temperature range of 340 to 400 degrees C using the power law model and the Langmuir-Hinshelhood model. It was shown that HDN and HDS of heavy gas oil follows first order kinetics. The activation energies for HDN and HDS reactions from the power law and Langmuir-Hinshelhood models were 94 and 96 kJ/mol and 113 and 137 kJ/mol, respectively. It was concluded that nitrogen and hydrogen sulfide adsorption have a significant influence on HDN and HDS reactions. 32 refs., 8 tabs., 7 figs.

  8. Drude weight and optical conductivity of a two-dimensional heavy-hole gas with k-cubic spin-orbit interactions

    Energy Technology Data Exchange (ETDEWEB)

    Mawrie, Alestin; Ghosh, Tarun Kanti [Department of Physics, Indian Institute of Technology-Kanpur, Kanpur 208 016 (India)

    2016-01-28

    We present a detailed theoretical study on zero-frequency Drude weight and optical conductivity of a two-dimensional heavy-hole gas (2DHG) with k-cubic Rashba and Dresselhaus spin-orbit interactions. The presence of k-cubic spin-orbit couplings strongly modifies the Drude weight in comparison to the electron gas with k-linear spin-orbit couplings. For large hole density and strong k-cubic spin-orbit couplings, the density dependence of Drude weight deviates from the linear behavior. We establish a relation between optical conductivity and the Berry connection. Unlike two-dimensional electron gas with k-linear spin-orbit couplings, we explicitly show that the optical conductivity does not vanish even for equal strength of the two spin-orbit couplings. We attribute this fact to the non-zero Berry phase for equal strength of k-cubic spin-orbit couplings. The least photon energy needed to set in the optical transition in hole gas is one order of magnitude smaller than that of electron gas. Types of two van Hove singularities appear in the optical spectrum are also discussed.

  9. Mechanisms of gas bubble retention and release: results for Hanford Waste Tanks 241-S-102 and 241-SY-103 and single-shell tank simulants

    International Nuclear Information System (INIS)

    Gauglitz, P.A.; Rassat, S.D.; Bredt, P.R.; Konynenbelt, J.H.; Tingey, S.M.; Mendoza, D.P.

    1996-09-01

    Research at Pacific Northwest National Laboratory (PNNL) has probed the physical mechanisms and waste properties that contribute to the retention and release of flammable gases from radioactive waste stored in underground tanks at Hanford. This study was conducted for Westinghouse Hanford Company as part of the PNNL Flammable Gas Project. The wastes contained in the tanks are mixes of radioactive and chemical products, and some of these wastes are known to generate mixtures of flammable gases, including hydrogen, nitrous oxide, and ammonia. Because these gases are flammable, their retention and episodic release pose a number of safety concerns

  10. Mechanisms of gas bubble retention and release: results for Hanford Waste Tanks 241-S-102 and 241-SY-103 and single-shell tank simulants

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, P.A.; Rassat, S.D.; Bredt, P.R.; Konynenbelt, J.H.; Tingey, S.M.; Mendoza, D.P.

    1996-09-01

    Research at Pacific Northwest National Laboratory (PNNL) has probed the physical mechanisms and waste properties that contribute to the retention and release of flammable gases from radioactive waste stored in underground tanks at Hanford. This study was conducted for Westinghouse Hanford Company as part of the PNNL Flammable Gas Project. The wastes contained in the tanks are mixes of radioactive and chemical products, and some of these wastes are known to generate mixtures of flammable gases, including hydrogen, nitrous oxide, and ammonia. Because these gases are flammable, their retention and episodic release pose a number of safety concerns.

  11. The potential for buoyant displacement gas release events in Tank 241-SY-102 after waste transfer from Tank 241-SY-101

    International Nuclear Information System (INIS)

    Wells, BE; Meyer, P.E.; Chen, G.

    2000-01-01

    Tank 241-SY-101 (SY-101) is a double-shell, radioactive waste storage tank with waste that, before the recent transfer and water back-dilution operations, was capable of retaining gas and producing buoyant displacement (BD) gas release events (GREs). Some BD GREs caused gas concentrations in the tank headspace to exceed the lower flammability limit (LFL). A BD GRE occurs when a portion of the nonconvective layer retains enough gas to become buoyant, rises to the waste surface, breaks up, and releases some of its stored gas. The installation of a mixer pump in 1993 successfully mitigated gas retention in the settled solids layer in SY-101 and has since prevented BD GREs. However, operation of the mixer pump over the years caused gas retention in the floating crust layer and a corresponding accelerated waste level growth. The accelerating crust growth trend observed in 1997--98 led to initiation of sequences of waste removal and water back-dilutions in December 1999. Waste is removed from the mixed slurry layer in Tank SY-101 and transferred into Tank 241-Sy-102 (SY-102). Water is then added back to dissolve soluble solids that retain gas. The initial transfer of 89,500 gallons of SY-101 waste, diluted in-line at 0.94:1 by volume with water, to SY-102 was conducted in December 1999. The second transfer of 230,000 gallons of original SY-101 waste, diluted approximately 0.9:1, was completed in January 2000, and the third transfer of 205,500 gallons of original SY-101 waste diluted at 0.9:1 was completed in March 2000

  12. DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway.

    Science.gov (United States)

    Bai, Juli; Cervantes, Christopher; Liu, Juan; He, Sijia; Zhou, Haiyan; Zhang, Bilin; Cai, Huan; Yin, Dongqing; Hu, Derong; Li, Zhi; Chen, Hongzhi; Gao, Xiaoli; Wang, Fang; O'Connor, Jason C; Xu, Yong; Liu, Meilian; Dong, Lily Q; Liu, Feng

    2017-11-14

    Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the DNA-sensing cGAS-cGAMP-STING pathway. Fat-specific knockout of disulfide-bond A oxidoreductase-like protein (DsbA-L), a chaperone-like protein originally identified in the mitochondrial matrix, impaired mitochondrial function and promoted mtDNA release, leading to activation of the cGAS-cGAMP-STING pathway and inflammatory responses. Conversely, fat-specific overexpression of DsbA-L protected mice against high-fat diet-induced activation of the cGAS-cGAMP-STING pathway and inflammation. Taken together, we identify DsbA-L as a key molecule that maintains mitochondrial integrity. DsbA-L deficiency promotes inflammation and insulin resistance by activating the cGAS-cGAMP-STING pathway. Our study also reveals that, in addition to its well-characterized roles in innate immune surveillance, the cGAS-cGAMP-STING pathway plays an important role in mediating obesity-induced metabolic dysfunction.

  13. Mechanisms of gas retention and release: Experimental results for Hanford single-shell waste tanks 241-A-101, 241-S-106, and 241-U-103

    International Nuclear Information System (INIS)

    Rassat, S.D.; Caley, S.M.; Bredt, P.R.; Gauglitz, P.A.; Rinehart, D.E.; Forbes, S.V.

    1998-09-01

    The 177 underground waste storage tanks at the Hanford Site contain millions of gallons of radioactive waste resulting from the purification of nuclear materials and related processes. Through various mechanisms, flammable gas mixtures of hydrogen, ammonia, methane, and nitrous oxide are generated and retained in significant quantities within the waste in many (∼25) of these tanks. The potential for large releases of retained gas from these wastes creates a flammability hazard. It is a critical component of the effort to understand the flammability hazard and a primary goal of this laboratory investigation to establish an understanding of the mechanisms of gas retention and release in these wastes. The results of bubble retention experimental studies using waste samples from several waste tanks and a variety of waste types support resolution of the Flammable Gas Safety Issue. Gas bubble retention information gained in the pursuit of safe storage will, in turn, benefit future waste operations including salt-well pumping, waste transfers, and sluicing/retrieval

  14. Modeling and simulation of a pseudo-two-phase gas-liquid column reactor for thermal hydrocracking of petroleum heavy fractions

    Directory of Open Access Journals (Sweden)

    E.M. Matos

    2002-07-01

    Full Text Available This work presents a model to predict the behavior of velocity, gas holdup and local concentration fields in a pseudo-two-phase gas-liquid column reactor applied for thermal hydrocracking of petroleum heavy fractions. The model is based on the momentum and mass balances for the system, using an Eulerian-Eulerian approach. Using the k-epsilon model,fluid dynamics accounts for both laminar and turbulent flows, with discrete small bubbles (hydrogen flowing in a continuous pseudohomogeneous liquid phase (oil and catalyst particles. The petroleum is assumed to be a mixture of pseudocomponents, grouped by similar chemical structural properties, and the thermal hydrocracking is taken into account using a kinetic network based on these pseudocomponents.

  15. A simple method to evaluate the fission gas release at fuel grain boundary including the grain growth both at constant and at transient power histories

    International Nuclear Information System (INIS)

    Paraschiv, M.; Paraschiv, A.

    1991-01-01

    A method to rewrite Fick's second law for a region with a moving boundary when the moving law in time of this boundary is known, has been proposed. This method was applied to Booth's sphere model for radioactive and stable fission product diffusion from the oxide fuel grain in order to take into account the grain growth. The solution of this new equation was presented in the mathematical formulation for power histories from ANS 5.4 model for the stable species. It is very simple to apply and very accurate. The results obtained with this solution for constant and transient temperatures show that the fission gas release (FGR) at grain boundary is strongly dependent on kinetics of grain growth. The utilization of two semiempirical grain growth laws, from published information, shows that the fuel microstructural properties need to be multicitly considered in the fission gas release for every manufacturer of fuel. (orig.)

  16. Comparison of vibration and noise level on the boiler during operation of fuel heavy oil (mazut) and on natural gas in TO 'Istok' - Toplifikacija - Joint-Stock Co. for district heating Skopje (Macedonia)

    International Nuclear Information System (INIS)

    Kirovski, Hristo; Ninevski, Gjorgji; Sekovanikj, Ivica; Dzhingov, Gjorgji

    1999-01-01

    In the beginning of the heat season 1997/98, we started to use natural gas as a second fuel (the basic fuel is heavy fuel oil). Preparations were made for the use of natural gas in half of the TO 'Istok' Plant capacity (147 MW) in Skopje (Macedonia). During operation on natural gas, we noted that the levels of vibration and noise are higher when operating on heavy fuel oil. This was the reason why an investigation was carried out through a special company working on that issue. The investigation was made by measurement of vibration levels and noise at the boiler furnace in various orientation and levels. This material gives the results and conclusions from that investigation. A comparison has been made of the dynamic conditions and noise levels of the same boilers during operation on heavy fuel oil and on natural gas. We also compared the dynamic conditions and noise levels of different boilers during operations on natural gas, with different equipment for the atomizing of the natural gas. Conclusions on the dynamic conditions of the investigated boilers while operating on heavy fuel oil and on natural gas are given at the end of this material. (Author)

  17. Influence of feedstock type on heavy coker gas oil quality; A influencia do tipo de carga na qualidade do gasoleo pesado de coque

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Claudine T.A.S.; Barros, Francisco C.C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    Over the past few years, the great challenge to the Oil Industry has been the processing of increasingly heavier feedstock seeking to meet the growing demand for medium distillates and, at the same time, the reduction of the production of fuel oils. In this scenario, the Delayed Coking Unit (DCU) appears to be an attractive technology for the processing of heavy and ultra heavy crudes. The addition of Asphaltene Residue produced by the Solvent Deasphalting Unit (SDA) to the Vacuum Residue, traditional feedstock of these units, has been a new tendency in the composition of the feedstock, with the intention of converting the residual fractions into value added liquid oil products. Results obtained in pilot plants show that asphaltene residue alters the yield and the quality of the products of the DCU, especially those of Heavy Coker Gas Oil (HKGO) that is incorporated in the feedstock of the Fluid Catalytic Cracking Unit (FCCU). The alteration in the quality of the HKGO negatively impacts on the conservation of the FCCU. The insertion of DCU in refineries that possess SDA in their refining systems has shown itself to be fundamental for the reduction of the production of fuel oils. However, to define the quantity and quality of asphaltene residue to be incorporated in the feedstock of the UCR, the best operating conditions and the necessary project adaptations to this unit are fundamental and they should be analyzed with the objective of maximizing the profitability of the refineries. (author)

  18. Effects of particulates, heavy metals and acid gas on the removals of NO and PAHs by V2O5-WO3 catalysts in waste incineration system

    International Nuclear Information System (INIS)

    Chang, Feng-Yim; Chen, Jyh-Cherng; Wey, Ming-Yen; Tsai, Shih-An

    2009-01-01

    This study investigated the activities of prepared and commercial V 2 O 5 -WO 3 catalysts for simultaneous removals of NO and polycyclic aromatic hydrocarbons (PAHs) and the influences of particulates, heavy metals, SO 2 , and HCl on the performances of catalysts. The experiments were carried out in a laboratory-scale waste incineration system equipped with a catalyst reactor. The DREs of PAHs by prepared and commercial V 2 O 5 -WO 3 catalysts were 64% and 72%, respectively. Increasing the particulate concentrations in flue gas suppressed the DRE of PAHs, but increasing the carbon content on surface of catalysts promotes the NO conversions. The DRE of PAHs by the catalysts was significantly decreased by the increased concentrations of heavy metal Cd, but was promoted by high concentration of Pb. The influence level of SO 2 was higher than HCl on the performances of V 2 O 5 -WO 3 catalysts for PAHs removal, but was lower than HCl for NO removal. Prepared and commercial V 2 O 5 -WO 3 catalysts have similar trends on the effects of particulates, heavy metals, SO 2 , and HCl. The results of ESCA analysis reveal that the presences of these pollutants on the surface of catalysts did not change the chemical state of V and W.

  19. Safety assessment for proposed pump mixing operations to mitigate episodic gas releases in tank 241-101-SY: Hanford Site, Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Lentsch, J.W., Westinghouse Hanford

    1996-05-16

    This safety assessment addresses each of the elements required for the proposed action to remove a slurry distributor and to install, operate, and remove a mixing pump in Tank 241-SY-101, which is located within the Hanford Site, Richland, Washington. The proposed action is required as part of an ongoing evaluation of various mitigation concepts developed to eliminate episodic gas releases that result in hydrogen concentrations in the tank dome space that exceed the lower flammability limit.

  20. A safety assessment for proposed pump mixing operations to mitigate episodic gas releases in tank 241-SY-101: Hanford Site,Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Lentsch, J.W.

    1996-07-01

    This safety assessment addresses each of the elements required for the proposed action to remove a slurry distributor and to install, operate, and remove a mixing pump in Tank 241-SY-101,which is located within the Hanford Site, Richland, Washington.The proposed action is required as part of an ongoing evaluation of various mitigation concepts developed to eliminate episodic gas releases that result in hydrogen concentrations in the tank dome space that exceed the lower flammability limit.

  1. Comparing PAH availability from manufactured gas plant soils and sediments with chemical and biological tests. 1. PAH release during water desorption and supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, S.B.; Poppendieck, D.G.; Grabanski, C.B.; Loehr, R.C. [University of North Dakota, Grand Forks, ND (US). Energy and Environmental Research Center

    2002-11-15

    Soil and sediment samples from OG (oil gas) and CG (coal gas) manufactured gas plant (MGP) sites in the United States that had been closed for about 50 years were selected to represent a range of PAH concentrations and sample matrix compositions. Samples varied from vegetated soils to lampblack soot and had carbon contents from 3 to 87 wt%. Supercritical carbon dioxide, SFE desorption and water/XAD{sub 2} desorption curves were determined and fit with a simple two-site model to determine the rapid-released fraction (F) for PAHs ranging from naphthalene to benzo-(ghi)perylene. F values varied greatly among the samples. Release rates did not correlate with sample matrix characteristics including PAH concentrations, elemental composition or 'hard' and 'soft' organic carbon, indicating that PAH release cannot easily be estimated on the basis of sample matrix composition. F values for CG site samples obtained with SFE and water desorption agreed well but SFE yielded higher F values for the OG samples. These behaviors were attributed to the stronger ability of carbon dioxide than water to desorb PAHs from the highly aromatic (hard) carbon of the OG matrixes, while carbon dioxide and water showed similar abilities to desorb PAHs from the more polar (soft) carbon of the CG samples. The combined SFE and water desorption approaches should improve the understanding of PAH sequestration and release from contaminated soils and sediments and provide the basis for subsequent studies, using the same samples to compare PAH release with PAH availability to earthworms. 46 refs., 4 figs., 4 tabs.

  2. Comparing PAH availability from manufactured gas plant soils and sediments with chemical and biological tests. 1. PAH release during water desorption and supercritical carbon dioxide extraction.

    Science.gov (United States)

    Hawthorne, Steven B; Poppendieck, Dustin G; Grabanski, Carol B; Loehr, Raymond C

    2002-11-15

    Soil and sediment samples from oil gas (OG) and coal gas (CG) manufactured gas plant (MGP) sites were selected to represent a range of PAH concentrations (150-40,000 mg/kg) and sample matrix compositions. Samples varied from vegetated soils to lampblack soot and had carbon contents from 3 to 87 wt %. SFE desorption (120 min) and water/XAD2 desorption (120 days) curves were determined and fit with a simple two-site model to determine the rapid-released fraction (F) for PAHs ranging from naphthalene to benzo[ghi]perylene. F values varied greatly among the samples, from ca. 10% to >90% for the two- and three-ring PAHs and from <1% to ca. 50% for the five- and six-ring PAHs. Release rates did not correlate with sample matrix characteristics including PAH concentrations, elemental composition (C, H, N, S), or "hard" and "softs" organic carbon, indicating that PAH release cannot easily be estimated on the basis of sample matrix composition. Fvalues for CG site samples obtained with SFE and water desorption agreed well (linear correlation coefficient, r2 = 0.87, slope = 0.93), but SFE yielded higher F values for the OG samples. These behaviors were attributed to the stronger ability of carbon dioxide than water to desorb PAHs from the highly aromatic (hard) carbon of the OG matrixes, while carbon dioxide and water showed similar abilities to desorb PAHs from the more polar (soft) carbon of the CG samples. The combined SFE and water desorption approaches should improve the understanding of PAH sequestration and release from contaminated soils and sediments and provide the basis for subsequent studies using the same samples to compare PAH release with PAH availability to earthworms.

  3. The feasibility of the gas micro-turbines application in the heavy oil produced from onshore mature fields; A viabilidade do uso de micro-turbinas a gas em campos maduros onshore de oleos pesados

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Arlindo Antonio de; Santos, Edmilson Moutinho dos [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia. Programa Interunidades de Pos-graduacao em Energia

    2004-07-01

    This article presents a synthesis of the fast advances in micro co-generation technology and their possible applications in fields of petroleum. The subject is focus of a research of the authors and the preliminary results indicate a potential of contributing for the optimization of mature fields of heavy oil. In general, this technology involves smaller environmental impact and produces better efficiency in those uses that require heat and electricity. An application interesting it is the use of gas micro-turbines, operating in co-generation in a (heavy) oil fields onshore, where it is possible increment of the production to the if it uses the steam injection as method of secondary recovery. The idea of using the heat to improve the productivity of the wells and to increase the recovery factor is almost as old as the industry of the petroleum. The technique consists of heating up the oil to reduce his/her viscosity and to facilitate the drainage. Nowadays, the use of the steam injection is usual in fields of heavy oils (degree API <20), high viscosity (> 500 cp), reservoirs no deep (<1300 m) and net pay in the interval from 5 to 50 m. The innovation, here, is the use of a group of micro-turbines moved to gas (no rare, burned in the flare) to generate the steam 'in loco' (near to the well) and electricity for own consumption or even commercialization. This article presents a case study of the economical potential the use of four gas micro-turbines, operating in micro cogeneration, in a field of 6,6 km{sup 2} in the Brazilian Northeast. (author)

  4. Fission gas release from the sintered UO{sub 2} fuel; Oslobadjanje fisionih gasova iz goriva od sinterovanog UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sigulinski, F; Stevanovic, M [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1966-11-15

    This paper shoes the phenomena which control fission gases release from the sintered UO{sub 2} dependent of the burnup rate: ejection, release, diffusion, increased fission gas accumulation causing structural changes in the fuel. release of fission gases from the fuel for power reactors was studied as well. The influence of factors as temperature, characteristics of fuel, burnup rate and burnup level was analyzed. Prikazani su mehanizmi koji kontrolisu izdvajanje fisionih gasova iz sinterovanog UO{sub 2} pri razlicitim brzinama izgaranja: izletanje, izbijanje, difuzija, povecano izdvajanje fisionih gasova koje prati strukturne promene u gorivu. Razmatrano je proucavanje izdvajanja fisionih gasova iz goriva za reaktore snage. Analiziran je uticaj faktora kao sto su temperatura, karakteristike goriva, brzina i stepen izgaranja (author)

  5. Study of the consequences of the rupture of a pressure tube in the tank of a gas-cooled, heavy-water moderated reactor

    International Nuclear Information System (INIS)

    Hareux, F.; Roche, R.; Vrillon, B.

    1964-01-01

    Bursting of a pressure tube in the tank of a heavy water moderated-gas cooled reactor is an accident which has been studied experimentally about EL-4. A first test (scale 1) having shown that the burst of a tube does not cause the rupture of adjacent tubes, tests on the tank resistance have been undertaken with a very reduced scale model (1 to 10). It has been found that the tank can endure many bursts of tube without any important deformation. Transient pressure in the tank is an oscillatory weakened wave, the maximum of which (pressure peak) has been the object of a particular experimental study. It appears that the most important parameters which affect the pressure peak are; the pressure of the gas included in the bursting pressure tube, the volume of this gas, the mass of air included in the tank and the nature of the gas. A general method to calculate the pressure peak value in reactor tanks has been elaborated by direct application of experimental data. (authors) [fr

  6. 77 FR 51499 - Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty...

    Science.gov (United States)

    2012-08-24

    ... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration 49 CFR Part 535 [NHTSA 2012-0126] RIN 2127-AK74 Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium... purpose of reducing greenhouse gas (GHG) emissions because the GHG standards fundamentally regulate fuel...

  7. Modifications to Langley 0.3-m TCT adaptive wall software for heavy gas test medium, phase 1 studies

    Science.gov (United States)

    Murthy, A. V.

    1992-01-01

    The scheme for two-dimensional wall adaptation with sulfur hexafluoride (SF6) as test gas in the NASA Langley Research Center 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT) is presented. A unified version of the wall adaptation software has been developed to function in a dual gas operation mode (nitrogen or SF6). The feature of ideal gas calculations for nitrogen operation is retained. For SF6 operation, real gas properties have been computed using the departure function technique. Installation of the software on the 0.3-m TCT ModComp-A computer and preliminary validation with nitrogen operation were found to be satisfactory. Further validation and improvements to the software will be undertaken when the 0.3-m TCT is ready for operation with SF6 gas.

  8. Effects of sorption agents on heavy metal release form incinerator slag; Laesst sich die Freisetzung von Schwermetallen aus MVA-Schlacken durch Zugabe von Sorbenten veraendern?

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, U. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Kersten, M. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany). Inst. fuer Geowissenschaften

    2003-11-01

    It was investigated inhowfar additions of sorption agents will influence the solution of heavy metals in incinerator slag. [German] Es wurde untersucht, ob nicht durch Zugabe bestimmter Stoffe zur Muellschlacke die Loesung von Schwermetallen beschleunigt werden kann. (orig.)

  9. Some effects of gas adsorption on the high temperature volatile release behavior of a terrestrial basalt, tektite and lunar soil

    Science.gov (United States)

    Graham, D. G.; Muenow, D. W.; Gibson, E. K., Jr.

    1979-01-01

    Mass pyrograms obtained from high-temperature, mass psectrometric pyrolysis of a glassy theoleiitic submarine basalt and a tektite, ground in air to less than 64 microns, have shown N2 and SO release patterns very similar to those from the pyrolysis of mature lunar soil fines. The N2 and CO release behavior from the terrestrial samples reproduces the biomodal, high-temperature (approximately 700 and 1050 C) features from the lunar samples. Unground portions of the basalt and tektite show no release of N2 and CO during pyrolysis. Grinding also alters the release behavior and absolute amounts of H2O and CO2. It is suggested that adsorption of atmospheric gases in addition to solar wind implantation of ions may account for the wide range of values in previously reported concentrations of carbon and nitrogen from lunar fines.

  10. The diversity of the effects of sulfur mustard gas inhalation on respiratory system 10 years after a single, heavy exposure: analysis of 197 cases.

    Science.gov (United States)

    Emad, A; Rezaian, G R

    1997-09-01

    To find out the late pulmonary sequelae of sulfur mustard gas inhalation in 197 veterans, 10 years after their exposure. Cross-sectional clinical study. University hospital. One hundred ninety-seven veterans with a single, heavy exposure to sulfur mustard gas in 1986 and 86 nonexposed veterans as their control group. Pulmonary function tests, carbon monoxide diffusion capacity, bronchoscopy, and high-resolution CT of the chest were performed in all patients. Transbronchial lung biopsy was done in 24 suspected cases of pulmonary fibrosis. Asthma was diagnosed in 21 (10.65%), chronic bronchitis in 116 (58.88%), bronchiectasis in 17 (8.62%), airway narrowing due to searing or granulation tissue in 19 (9.64%), and pulmonary fibrosis in 24 (12.18%) cases. None of these were found among the control group except for a single case of chronic bronchitis. Although the respiratory symptoms of an acute sulfur mustard gas inhalation are usually transient and nonspecific, it can lead to the development of a series of chronic destructive pulmonary sequelae in such cases.

  11. Critical confrontation of standard and more sophisticated methods for modelling the dispersion in air of heavy gas clouds; evaluation and illustration of the intrinsic limitations of both categories

    International Nuclear Information System (INIS)

    Riethmuller, M.L.

    1983-01-01

    Mathematical models of gas dispersion have evolved drastically since the 1930's. For a long time, the most widely used approach was the so-called Gaussian model as described in practical terms by Turner or box models which have shown relative merits. In the field of heavy gas dispersion, the use of such approaches appeared somewhat limited and therefore new models have been proposed. Some of these new generation models were making use of the latest progress in turbulence modelling as derived from laboratory work as well as numerical advances. The advent of faster and larger computers made possible the development of three dimensional codes that were computing both flow field and gas dispersion taking into account details of the ground obstacles, heat exchange and possibly phase changes as well. The description of these new types of models makes them appear as a considerable improvement over the simpler approaches. However, recent comparisons between many of these have led to the conclusion that the scatter between predictions attained with sophisticated models was just as large as with other ones. It seems therefore, that current researchers might have fallen into the trap of confusing mathematical precision with accuracy. It is therefore felt necessary to enlighten this question by an investigation which, rather than comparing individual models, would analyse the key features of both approaches and put in evidence their relative merits and degree of realism when being really applied

  12. FIELD DEMONSTRATION OF A MEMBRANE PROCESS TO RECOVER HEAVY HYDROCARBONS AND TO REMOVE WATER FROM NATURAL GAS; F

    International Nuclear Information System (INIS)

    Unknown

    2002-01-01

    The objective of this project is to design, construct and field demonstrate a 3-MMscfd membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. The gas processed by the membrane system will meet pipeline specifications for dew point and Btu value, and the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. The BP-Amoco gas processing plant in Pascagoula, MS was finalized as the location for the field demonstration. Detailed drawings of the MTR membrane skid (already constructed) were submitted to the plant in February, 2000. However, problems in reaching an agreement on the specifications of the system compressor delayed the project significantly, so MTR requested (and was subsequently granted) a no-cost extension to the project. Following resolution of the compressor issues, the goal is to order the compressor during the first quarter of 2002, and to start field tests in mid-2002. Information from potential users of the membrane separation process in the natural gas processing industry suggests that applications such as fuel gas conditioning and wellhead gas processing are the most promising initial targets. Therefore, most of our commercialization effort is focused on promoting these applications. Requests for stream evaluations and for design and price quotations have been received through MTR's web site, from direct contact with potential users, and through announcements in industry publications. To date, about 90 commercial quotes have been supplied, and orders totaling about$1.13 million for equipment or rental of membrane units have been received

  13. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  14. FIELD DEMONSTRATION OF A MEMBRANE PROCESS TO RECOVER HEAVY HYDROCARBONS AND TO REMOVE WATER FROM NATURAL GAS

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; T. Hofmann; J. Kaschemekat; K.A. Lokhandwala; Membrane Group; Module Group; Systems Group

    2001-01-11

    The objective of this project is to design, construct and field demonstrate a 3-MMscfd membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world conditions is required to convince industry users of the efficiency and reliability of the process. The system will be designed and fabricated by Membrane Technology and Research, Inc. (MTR) and then installed and operated at British Petroleum (BP)-Amoco's Pascagoula, MS plant. The Gas Research Institute will partially support the field demonstration and BP-Amoco will help install the unit and provide onsite operators and utilities. The gas processed by the membrane system will meet pipeline specifications for dewpoint and Btu value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. At the end of this demonstration project the process will be ready for commercialization. The route to commercialization will be developed during this project and may involve collaboration with other companies already servicing the natural gas processing industry.

  15. FIELD DEMONSTRATION OF A MEMBRANE PROCESS TO RECOVER HEAVY HYDROCARBONS AND TO REMOVE WATER FROM NATURAL GAS

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; R. Hofmann; K.A. Lokhandwala

    2003-02-14

    The objective of this project is to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world conditions would convince industry users of the efficiency and reliability of the process. The system has been designed and fabricated by Membrane Technology and Research, Inc. (MTR) and will be installed and operated at British Petroleum (BP)-Amoco's Pascagoula, MS plant. The Gas Research Institute will partially support the field demonstration and BP-Amoco will help install the unit and provide onsite operators and utilities. The gas processed by the membrane system will meet pipeline specifications for dewpoint and Btu value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. At the end of this demonstration project the process will be ready for commercialization. The route to commercialization will be developed during this project and may involve collaboration with other companies already servicing the natural gas processing industry.

  16. Supercritical fluid chromatography and high temperature liquid chromatography for the group-type separation of diesel fuels and heavy gas oils

    Energy Technology Data Exchange (ETDEWEB)

    Paproski, R.E.

    2008-07-01

    This thesis investigated the use of unconventional extraction columns for separating diesel fuels by supercritical fluid chromatography (SFC) and for separating heavy gas oils by high temperature normal phase high performance liquid chromatography (HPLC). The purpose was to improve group-type resolution of the fuels, although these methods are also commonly used to determine the proportion of saturates, mono-, di-, tri-, and polyaromatic hydrocarbons. Higher mobile phase flow rates and unconventional column dimensions were also studied to obtain faster analysis times with both SFC and HPLC. The highest group-type resolutions with SFC were obtained by serially coupling bare titania and bare silica columns. Short packed columns and monolithic silica columns were compared at high carbon dioxide flow rates for reducing SFC analysis time, with shortpacked columns achieving 7-fold lower separation times while maintaining significant resolution. Three diesel samples had better resolution and analysis time. A thermally stable bare zircoma column for normal phase HPLC was studied at temperatures up to 200 degrees C. An increase in temperature resulted in lower retention of twenty five aromatic model compounds. Considerable improvements in peak shape, efficiency, group-type selectivity, and column re-equilibration times were obtained at elevated temperatures. At temperatures over 100 degrees C, indole and carbazole thermally decomposed in a hexane/dichloromethane mobile phase. The first order decomposition of carbazole was studied in further detail. A high resolution method was developed using titania and silica columns with valve-switching and dual gradients to separate 3 heavy gas oils. Separation was achieved in only 3 minutes using a fast analysis time method in a titania column at high flow rates.

  17. The footprint of CO2 leakage in the water-column: Insights from numerical modeling based on a North Sea gas release experiment

    Science.gov (United States)

    Vielstädte, L.; Linke, P.; Schmidt, M.; Sommer, S.; Wallmann, K.; McGinnis, D. F.; Haeckel, M.

    2013-12-01

    Assessing the environmental impact of potential CO2 leakage from offshore carbon dioxide storage sites necessitates the investigation of the corresponding pH change in the water-column. Numerical models have been developed to simulate the buoyant rise and dissolution of CO2 bubbles in the water-column and the subsequent near-field dispersion of dissolved CO2 in seawater under ocean current and tidal forcing. In order to test and improve numerical models a gas release experiment has been conducted at 80 m water-depth within the Sleipner area (North Sea). CO2 and Kr (used as inert tracer gas) were released on top of a benthic lander at varying gas flows (impact of such leakage rates is limited to the near-field bottom waters, due to the rapid dissolution of CO2 bubbles in seawater (CO2 is being stripped within the first two to five meters of bubble rise). In particular, small bubbles, which will dissolve close to the seafloor, may cause a dangerous low-pH environment for the marine benthos. However, on the larger scale, the advective transport by e.g. tidal currents, dominates the CO2 dispersal in the North Sea and dilutes the CO2 peak quickly. The model results show that at the small scales (impact on the marine environment, thereby reducing pH substantially (by 0.4 units) within a diameter of less than 50 m around the release spot (depending on the duration of leakage and the current velocities). Strong currents and tidal cycles significantly reduce the spreading of low-pH water masses into the far-field by efficiently diluting the amount of CO2 in ambient seawater.

  18. Source strength and dispersion of CO2 releases from high-pressure pipelines: CFD model using real gas equation of state

    International Nuclear Information System (INIS)

    Liu, Xiong; Godbole, Ajit; Lu, Cheng; Michal, Guillaume; Venton, Philip

    2014-01-01

    Highlights: • Validated CFD models for decompression and dispersion of CO 2 releases from pipelines. • Incorporation of real gas EOS into CFD code for source strength estimation. • Demonstration of better performance of SST k–ω turbulence model for jet flow. • Demonstration of better performance of real gas EOS compared to ideal gas EOS. • Demonstration of superiority of CFD models over a commercial risk assessment package. - Abstract: Transportation of CO 2 in high-pressure pipelines forms a crucial link in the ever-increasing application of Carbon Capture and Storage (CCS) technologies. An unplanned release of CO 2 from a pipeline presents a risk to human and animal populations and the environment. Therefore it is very important to develop a deeper understanding of the atmospheric dispersion of CO 2 before the deployment of CO 2 pipelines, to allow the appropriate safety precautions to be taken. This paper presents a two-stage Computational Fluid Dynamics (CFD) study developed (1) to estimate the source strength, and (2) to simulate the subsequent dispersion of CO 2 in the atmosphere, using the source strength estimated in stage (1). The Peng–Robinson (PR) EOS was incorporated into the CFD code. This enabled accurate modelling of the CO 2 jet to achieve more precise source strength estimates. The two-stage simulation approach also resulted in a reduction in the overall computing time. The CFD models were validated against experimental results from the British Petroleum (BP) CO 2 dispersion trials, and also against results produced by the risk management package Phast. Compared with the measurements, the CFD simulation results showed good agreement in both source strength and dispersion profile predictions. Furthermore, the effect of release direction on the dispersion was studied. The presented research provides a viable method for the assessment of risks associated with CCS

  19. Coupled atmosphere-soil-vegetation modelling for the assessment of the impact of atmospheric releases of heavy metals and of persistent organic pollutants at the European scale

    International Nuclear Information System (INIS)

    Queguiner, Solen

    2008-01-01

    The objective of this research thesis is to couple a model of atmospheric dispersion with a multi-environment model in order to perform impact studies related to atmospheric pollution by heavy metals and POPs (persistent organic pollutants). The author first presents the studied pollutants, their physical and chemical properties, and their effects on health. Then, he addresses the atmospheric modelling with a presentation of the used atmospheric dispersion model (POLAIR3D), and an application to heavy metals. Simulations are performed on a 4-year period in order to try to represent the inter-annual variability of atmospheric lead and cadmium concentrations. The next part reports the modelling of POPs which required the introduction of a soil model to address re-emissions. Results are compared with provided measurements. The fourth part reports the modelling of agricultural environments in the impact model, and more particularly physical processes and parameters proper to heavy metals and POPs. The author finally reports two case studies, one related to heavy metals, and the other to POPs [fr

  20. Low NO sub x heavy fuel combustor concept program. Phase 1A: Combustion technology generation coal gas fuels

    Science.gov (United States)

    Sherlock, T. P.

    1982-01-01

    Combustion tests of two scaled burners using actual coal gas from a 25 ton/day fluidized bed coal gasifier are described. The two combustor configurations studied were a ceramic lined, staged rich/lean burner and an integral, all metal multiannual swirl burner (MASB). The tests were conducted over a range of temperature and pressures representative of current industrial combustion turbine inlet conditions. Tests on the rich lean burner were conducted at three levels of product gas heating values: 104, 197 and 254 btu/scf. Corresponding levels of NOx emissions were 5, 20 and 70 ppmv. Nitrogen was added to the fuel in the form of ammonia, and conversion efficiencies of fuel nitrogen to NOx were on the order of 4 percent to 12 percent, which is somewhat lower than the 14 percent to 18 percent conversion efficiency when src-2 liquid fuel was used. The MASB was tested only on medium btu gas (220 to 270 btu/scf), and produced approximately 80 ppmv NOx at rated engine conditions. Both burners operated similarly on actual coal gas and erbs fuel, and all heating values tested can be successfully burned in current machines.

  1. Accidental behaviour of nuclear fuel in a warehousing site under air: investigation of the nuclear ceramic oxidation and of fission gas release

    International Nuclear Information System (INIS)

    Desgranges, L.

    2006-12-01

    After a brief presentation of the context of his works, i.e. the nuclear fuel, its behaviour in a nuclear reactor, and studies performed in high activity laboratory, the author more precisely presents its research topic: the behaviour of defective nuclear fuel in air. Then, he describes the researches performed in three main directions: firstly, the characterization and understanding of fission gas localisation (experimental localisation, understanding of the bubble forming mechanisms), secondly, the determination of mechanisms related to oxidation (atomic mechanisms related to UO 2 oxidation, oxidation of fragments of irradiated fuel, the CROCODILE installation). He finally presents his scientific project which notably deals with fission gas release (from UO 2 to U 3 O 7 , and from U 3 O 7 to U 3 O 8 ), and with further high activity laboratory experiments

  2. 76 FR 3142 - Release of Exposure Draft Technical Bulletins; Accounting for Oil and Gas Resources and Federal...

    Science.gov (United States)

    2011-01-19

    ... FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Release of Exposure Draft Technical Bulletins... Accounting Standards Advisory Board. ACTION: Notice. Board Action: Pursuant to 31 U.S.C. 3511(d), the Federal... October, 2010, notice is hereby given that the Federal Accounting Standards Advisory Board (FASAB) has...

  3. Effects of dystocia on blood gas parameters, acid-base balance and serum lactate concentration in heavy draft newborn foals

    Science.gov (United States)

    KIMURA, Yuki; AOKI, Takahiro; CHIBA, Akiko; NAMBO, Yasuo

    2017-01-01

    ABSTRACT Dystocia is often lethal for neonatal foals; however, its clinicopathological features remain largely unknown. We investigated the effect of dystocia on the foal blood profile. Venous blood samples were collected from 35 foals (5 Percheron and 30 crossbreds between Percheron, Belgian, and Breton heavy draft horses) at 0 hr, 1 hr, 12 hr and 1 day after birth. Dystocia was defined as prolonged labor >30 min with strong fetal traction with or without fetal displacement. The dystocia group (n=13) showed lower mean values for pH (P90 mmHg) were observed in three foals in the dystocia group but in none of the foals in the normal birth group immediately after birth. These results suggest that dystocia results in lactic acidosis and may be related to respiratory distress. PMID:28400704

  4. Methane release

    International Nuclear Information System (INIS)

    Seifert, M.

    1999-01-01

    The Swiss Gas Industry has carried out a systematic, technical estimate of methane release from the complete supply chain from production to consumption for the years 1992/1993. The result of this survey provided a conservative value, amounting to 0.9% of the Swiss domestic output. A continuation of the study taking into account new findings with regard to emission factors and the effect of the climate is now available, which provides a value of 0.8% for the target year of 1996. These results show that the renovation of the network has brought about lower losses in the local gas supplies, particularly for the grey cast iron pipelines. (author)

  5. Swift heavy ion irradiated SnO_2 thin film sensor for efficient detection of SO_2 gas

    International Nuclear Information System (INIS)

    Tyagi, Punit; Sharma, Savita; Tomar, Monika; Singh, Fouran; Gupta, Vinay

    2016-01-01

    Highlights: • Response of Ni"7"+ ion irradiated (100 MeV) SnO_2 film have been performed. • Effect of irradiation on the structural and optical properties of SnO_2 film is studied. • A decrease in operating temperature and increased response is seen after irradiation. - Abstract: Gas sensing response studies of the Ni"7"+ ion irradiated (100 MeV) and non-irradiated SnO_2 thin film sensor prepared under same conditions have been performed towards SO_2 gas (500 ppm). The effect of irradiation on the structural, surface morphological, optical and gas sensing properties of SnO_2 thin film based sensor have been studied. A significant decrease in operating temperature (from 220 °C to 60 °C) and increased sensing response (from 1.3 to 5.0) is observed for the sample after irradiation. The enhanced sensing response obtained for the irradiated SnO_2 thin film based sensor is attributed to the desired modification in the surface morphology and material properties of SnO_2 thin film by Ni"7"+ ions.

  6. Analyzing the Performance of a Dual Loop Organic Rankine Cycle System for Waste Heat Recovery of a Heavy-Duty Compressed Natural Gas Engine

    Directory of Open Access Journals (Sweden)

    Baofeng Yao

    2014-11-01

    Full Text Available A dual loop organic Rankine cycle (DORC system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE, and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT and low-temperature (LT cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.

  7. Use of natural gas on heavy duty vehicles in Brazil: experience, current scene and barriers that still persist; Utilizacao do gas natural em veiculos pesados no Brasil: experiencia, cenario atual e barreiras que ainda persistem

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Guilherme B.; Melo, Tadeu C.C.; Lastres, Luiz Fernando M. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    In the 80's, because of the oil crisis, the Natural Gas (NG) appeared as a fuel with a great potential for Diesel replacement in Heavy Duty Vehicles. At that time, PETROBRAS with other companies have developed partial conversion technologies from Diesel to NG, known as 'Dual Fuel'. Engine dynamometer and vehicle bus tests have been developed to verify its technical and economical viability. Because of several factors, the Dual Fuel Program did not advance and the experience was interrupted. At the same time, other experiences using NG Otto Cycle bus engines, manufactured in Brazil, have been conducted, mainly at Sao Paulo, nevertheless, without expansion. Currently, factors as increase of the NG converted light vehicles fleet; the NG excess in the National Market, which has contributed to the NG distribution net expansion; the Environmental Legislature in vigor, that continuously determine lower emission limits; the government interest in increasing the NG energy matrix share and in reducing Diesel fuel consumption, and the low NG industrial demand, compose together a great scene to the diffusion of NG as substitute to the Diesel fuel in Heavy Duty Vehicles. (author)

  8. Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture

    Science.gov (United States)

    The interest in using Flue Gas Desulfurization Gypsum(FGDG) has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using rece...

  9. Evidence for faulting related to dissociation of gas hydrate and release of methane off the southeastern United States

    Science.gov (United States)

    Dillon, William P.; Danforth, W.W.; Hutchinson, D.R.; Drury, R.M.; Taylor, M.H.; Booth, J.S.

    1998-01-01

    This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). An irregular, faulted, collapse depression about 38 x 18 km in extent is located on the crest of the Blake Ridge offshore from the south- eastern United States. Faults disrupt the sea floor and terminate or sole out about 40-500 m below the sea floor at the base of the gas hydrate stable zone, which is identified from the location of the bottom simulating reflection (BSR). Normal faults are common but reverse faults and folds also are widespread. Folds commonly convert upward into faults. Sediment diapirs and deposits of sediments that were erupted onto the sea floor are also present. Sea-floor depressions at faults may represent locations of liquid/gas vents. The collapse was probably caused by overpressures and by the decoupling of the overlying sediments by gassy muds that existed just beneath the zone of gas hydrate stability.

  10. Down the Rabbit Hole: toward appropriate discussion of methane release from gas hydrate systems during the Paleocene-Eocene thermal maximum and other past hyperthermal events

    Directory of Open Access Journals (Sweden)

    G. R. Dickens

    2011-08-01

    Full Text Available Enormous amounts of 13C-depleted carbon rapidly entered the exogenic carbon cycle during the onset of the Paleocene-Eocene thermal maximum (PETM, as attested to by a prominent negative carbon isotope (δ13C excursion and deep-sea carbonate dissolution. A widely cited explanation for this carbon input has been thermal dissociation of gas hydrate on continental slopes, followed by release of CH4 from the seafloor and its subsequent oxidation to CO2 in the ocean or atmosphere. Increasingly, papers have argued against this mechanism, but without fully considering existing ideas and available data. Moreover, other explanations have been presented as plausible alternatives, even though they conflict with geological observations, they raise major conceptual problems, or both. Methane release from gas hydrates remains a congruous explanation for the δ13C excursion across the PETM, although it requires an unconventional framework for global carbon and sulfur cycling, and it lacks proof. These issues are addressed here in the hope that they will prompt appropriate discussions regarding the extraordinary carbon injection at the start of the PETM and during other events in Earth's history.

  11. Gas release-based prescreening combined with reversed-phase HPLC quantitation for efficient selection of high-γ-aminobutyric acid (GABA)-producing lactic acid bacteria.

    Science.gov (United States)

    Wu, Qinglong; Shah, Nagendra P

    2015-02-01

    High γ-aminobutyric acid (GABA)-producing lactobacilli are promising for the manufacture of GABA-rich foods and to synthesize GRAS (generally recognized as safe)-grade GABA. However, common chromatography-based screening is time-consuming and inefficient. In the present study, Korean kimchi was used as a model of lactic acid-based fermented foods, and a gas release-based prescreening of potential GABA producers was developed. The ability to produce GABA by potential GABA producers in de Man, Rogosa, and Sharpe medium supplemented with or without monosodium glutamate was further determined by HPLC. Based on the results, 9 isolates were regarded as high GABA producers, and were further genetically identified as Lactobacillus brevis based on the sequences of 16S rRNA gene. Gas release-based prescreening combined with reversed-phase HPLC confirmation was an efficient and cost-effective method to identify high-GABA-producing LAB, which could be good candidates for probiotics. The GABA that is naturally produced by these high-GABA-producing LAB could be used as a food additive. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  12. The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology.

    Science.gov (United States)

    He, Jingfeng; Duan, Chenlong; Lei, Mingzhe; Zhu, Xuemei

    2016-01-01

    The secondary release of mercury from coal fly ash is a negative by-product from coal-fired power plants, and requires effective control to reduce environmental pollution. Analysing particle size distribution and composition of the coal fly ash produced by different mercury removing technologies indicates that the particles are generally less than 0.5 mm in size and are composed mainly of SiO2, Al2O3, and Fe2O3. The relationships between mercury concentration in the coal fly ash, its particle size, and loss of ignition were studied using different mercury removing approaches. The research indicates that the coal fly ash's mercury levels are significantly higher after injecting activated carbon or brominating activated carbon when compared to regular cooperating-pollution control technology. This is particularly true for particle size ranges of >0.125, 0.075-0.125, and 0.05-0.075 mm. Leaching experiments revealed the secondary release of mercury in discarded coal fly ash. The concentration of mercury in the coal fly ash increases as the quantity of injecting activated carbon or brominating activated carbon increases. The leached concentrations of mercury increase as the particle size of the coal fly ash increases. Therefore, the secondary release of mercury can be controlled by adding suitable activated carbon or brominating activated carbon when disposing of coal fly ash. Adding CaBr2 before coal combustion in the boiler also helps control the secondary release of mercury, by increasing the Hg(2+) concentration in the leachate. This work provides a theoretical foundation for controlling and removing mercury in coal fly ash disposal.

  13. Greenhouse gas emissions and reactive nitrogen releases during the life-cycles of staple food production in China and their mitigation potential

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Longlong [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ti, Chaopu [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Li, Bolun [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xia, Yongqiu [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Yan, Xiaoyuan, E-mail: yanxy@issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-06-15

    Life-cycle analysis of staple food (rice, flour and corn-based fodder) production and assessments of the associated greenhouse gas (GHG) and reactive nitrogen (Nr) releases, from environmental and economic perspectives, help to develop effective mitigation options. However, such evaluations have rarely been executed in China. We evaluated the GHG and Nr releases per kilogram of staple food production (carbon and Nr footprints) and per unit of net economic benefit (CO{sub 2-NEB} and Nr{sub -NEB}), and explored their mitigation potential. Carbon footprints of food production in China were obviously higher than those in some developed countries. There was a high spatial variation in the footprints, primarily attributable to differences in synthetic N use (or CH{sub 4} emissions) per unit of food production. Provincial carbon footprints had a significant linear relationship with Nr footprints, attributed to large contribution of N fertilizer use to both GHG and Nr releases. Synthetic N fertilizer applications and CH{sub 4} emissions dominated the carbon footprints, while NH{sub 3} volatilization and N leaching were the main contributors to the Nr footprints. About 564 (95% uncertainty range: 404–701) Tg CO{sub 2} eq GHG and 10 (7.4–12.4) Tg Nr-N were released every year during 2001–2010 from staple food production. This caused the total damage costs of 325 (70–555) billion ¥, equivalent to nearly 1.44% of the Gross Domestic Product of China. Moreover, the combined damage costs and economic input costs, accounted for 66%-80% of the gross economic benefit generated from food production. A reduction of 92.7 Tg CO{sub 2} eq yr{sup −1} and 2.2 Tg Nr-N yr{sup −1} could be achieved by reducing synthetic N inputs by 20%, increasing grain yields by 5% and implementing off-season application of straw and mid-season drainage practices for rice cultivation. In order to realize these scenarios, an ecological compensation scheme should be established to incentivize

  14. Greenhouse gas emissions and reactive nitrogen releases during the life-cycles of staple food production in China and their mitigation potential

    International Nuclear Information System (INIS)

    Xia, Longlong; Ti, Chaopu; Li, Bolun; Xia, Yongqiu; Yan, Xiaoyuan

    2016-01-01

    Life-cycle analysis of staple food (rice, flour and corn-based fodder) production and assessments of the associated greenhouse gas (GHG) and reactive nitrogen (Nr) releases, from environmental and economic perspectives, help to develop effective mitigation options. However, such evaluations have rarely been executed in China. We evaluated the GHG and Nr releases per kilogram of staple food production (carbon and Nr footprints) and per unit of net economic benefit (CO 2-NEB and Nr -NEB ), and explored their mitigation potential. Carbon footprints of food production in China were obviously higher than those in some developed countries. There was a high spatial variation in the footprints, primarily attributable to differences in synthetic N use (or CH 4 emissions) per unit of food production. Provincial carbon footprints had a significant linear relationship with Nr footprints, attributed to large contribution of N fertilizer use to both GHG and Nr releases. Synthetic N fertilizer applications and CH 4 emissions dominated the carbon footprints, while NH 3 volatilization and N leaching were the main contributors to the Nr footprints. About 564 (95% uncertainty range: 404–701) Tg CO 2 eq GHG and 10 (7.4–12.4) Tg Nr-N were released every year during 2001–2010 from staple food production. This caused the total damage costs of 325 (70–555) billion ¥, equivalent to nearly 1.44% of the Gross Domestic Product of China. Moreover, the combined damage costs and economic input costs, accounted for 66%-80% of the gross economic benefit generated from food production. A reduction of 92.7 Tg CO 2 eq yr −1 and 2.2 Tg Nr-N yr −1 could be achieved by reducing synthetic N inputs by 20%, increasing grain yields by 5% and implementing off-season application of straw and mid-season drainage practices for rice cultivation. In order to realize these scenarios, an ecological compensation scheme should be established to incentivize farmers to gradually adopt knowledge

  15. A proposal for a test method for assessment of hazard property HP 12 ("Release of an acute toxic gas") in hazardous waste classification - Experience from 49 waste.

    Science.gov (United States)

    Hennebert, Pierre; Samaali, Ismahen; Molina, Pauline

    2016-12-01

    A stepwise method for assessment of the HP 12 is proposed and tested with 49 waste samples. The hazard property HP 12 is defined as "Release of an acute toxic gas": waste which releases acute toxic gases (Acute Tox. 1, 2 or 3) in contact with water or an acid. When a waste contains a substance assigned to one of the following supplemental hazards EUH029, EUH031 and EUH032, it shall be classified as hazardous by HP 12 according to test methods or guidelines (EC, 2014a, 2014b). When the substances with the cited hazard statement codes react with water or an acid, they can release HCl, Cl 2 , HF, HCN, PH 3 , H 2 S, SO 2 (and two other gases very unlikely to be emitted, hydrazoic acid HN 3 and selenium oxide SeO 2 - a solid with low vapor pressure). Hence, a method is proposed:For a set of 49 waste, water addition did not produce gas. Nearly all the solid waste produced a gas in contact with hydrochloric acid in 5 min in an automated calcimeter with a volume >0.1L of gas per kg of waste. Since a plateau of pressure is reached only for half of the samples in 5 min, 6 h trial with calorimetric bombs or glass flasks were done and confirmed the results. Identification of the gases by portable probes showed that most of the tested samples emit mainly CO 2 . Toxic gases are emitted by four waste: metallic dust from the aluminum industry (CO), two air pollution control residue of industrial waste incinerator (H 2 S) and a halogenated solvent (organic volatile(s) compound(s)). HF has not been measured in these trials started before the present definition of HP 12. According to the definition of HP 12, only the H 2 S emission of substances with hazard statement EUH031 is accounted for. In view of the calcium content of the two air pollution control residue, the presence of calcium sulphide (EUH031) can be assumed. These two waste are therefore classified potentially hazardous for HP 12, from a total of 49 waste. They are also classified as hazardous for other properties (HP 7

  16. Comparative life cycle GHG emissions from local electricity generation using heavy oil, natural gas, and MSW incineration in Macau

    DEFF Research Database (Denmark)

    Song, Qingbin; Wang, Zhishi; Li, Jinhui

    2018-01-01

    Wh, respectively. The mean value for aggregated GHG emissions of the local power grid (imported electricity excluded) was 0.69kg CO2 per kWh, noticeably lower than many neighboring countries and regions, such as mainland China, Taiwan, and Japan. Our scenario analysis indicated that the development of natural gas......, for changing GHG emissions, and should be allocated to the highest priority for GHG reduction. All the obtained results could be useful for decisions makers, with providing a robust support for assessing the environmental performance and drawing up the appropriate improvement planning of power systems....

  17. Using heavy atom rare gas matrix to control the reactivity of 4-methoxybenzaldehyde: A comparison with benzaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Kus, Nihal [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Department of Physics, Anadolu University, 26470 Eskisehir (Turkey); Sharma, Archna; Reva, Igor; Fausto, Rui [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Lapinski, Leszek [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland)

    2012-04-14

    Different patterns of photochemical behavior were observed for 4-methoxybenzaldehyde (p-anisaldehyde) isolated in xenon and in argon matrices. Monomers of the compound isolated in solid Xe decarbonylate upon middle ultraviolet irradiation, yielding methoxybenzene (anisole), and CO. On the other hand, p-anisaldehyde isolated in an Ar matrix and subjected to identical irradiation, predominantly isomerizes to the closed-ring isomeric ketene (4-methoxycyclohexa-2,4-dien-1-ylidene) methanone. Experimental detection of a closed-ring ketene photoproduct, generated from an aromatic aldehyde, constitutes a rare observation. The difference between the patterns of photochemical transformations of p-anisaldehyde isolated in argon and xenon environments can be attributed to the external heavy-atom effect, where xenon enhances the rate of intersystem crossing from the singlet to the triplet manifold in which decarbonylation (via p-methoxybenzoyl radical) takes place. The parent compound, benzaldehyde, decarbonylates (to benzene + CO) when subjected to middle ultraviolet irradiation in both argon and xenon matrices. This demonstrates the role of the methoxy p-anisaldehyde substituent in activation of the reaction channel leading to the formation of the ketene photoproduct.

  18. Joint interpretation of geoelectrical and soil-gas measurements for monitoring CO2 releases at a natural analogue

    DEFF Research Database (Denmark)

    Sauer, U.; Watanabe, N.; Singh, Ashok

    2014-01-01

    the complex behaviour of temporal variations for the flow patterns. In particular, coupled migration of gas and water plays an important influencing role in this process. Site-specific, near surface geological features and meteorological conditions seem to exert great influence on the degassing pattern...... and flux measurements, self-potential (SP) and geoelectrical surveys) showed that the combination of geophysical methods with soil-gas analysis for mesoscale monitoring of the shallow subsurface above geologic CO2 storages can be a valuable tool for mapping and monitoring potential CO2 spread...... in the subsurface. Three measurement campaigns were undertaken - May 2011, July 2011 and April 2012 - at an analogue site in the Cheb Basin, Czech Republic, with the aim of studying CO2 leakages and their temporal and spatial behaviour. Results of geoelectrical investigations give an insight into the structural...

  19. Tritium gas and tritiated water vapour behaviour in the environment from releases into the atmosphere from fusion reactors

    International Nuclear Information System (INIS)

    Velarde, Marta; Perlado, Manuel

    2001-01-01

    The diffusion of tritium from fusion reactors follows different ways according to the present chemical form, tritium gas or tritiated water vapour. The atmospheric conditions, speed and direction of the wind, rain intensity or stability class, are key factors in the dry and wet deposition. The obtained results demonstrate that the wet deposition is critical for the incorporation of the tritiated water vapour to the natural biological chain. However, the dry deposition is the factor that influences in the tritium gas form. The conversion of HT into HTO in the soil is rapid (1-7 days), and 20% of HT deposited in the soil is reemitted to the atmosphere in the form HTO, while the rest incorporates into the biological cycle. The rain factor accelerates the incorporation of tritium to the ground, the superficial waters and the underground waters

  20. Steady-State Flammable Gas Release Rate Calculation And Lower Flammability Level Evaluation For Hanford Tank Waste

    International Nuclear Information System (INIS)

    Hu, T.A.

    2007-01-01

    Assess the steady-state flammability level at normal and off-normal ventilation conditions. The methodology of flammability analysis for Hanford tank waste is developed. The hydrogen generation rate model was applied to calculate the gas generation rate for 177 tanks. Flammability concentrations and the time to reach 25% and 100% of the lower flammability limit, and the minimum ventilation rate to keep from 100 of the LFL are calculated for 177 tanks at various scenarios.

  1. Coupled reaction-diffusion equations to model the fission gas release in the irradiation of the uranium dioxide

    International Nuclear Information System (INIS)

    Moyano, Edgardo A.; Scarpettini, Alberto F.

    2003-01-01

    A semi linear model of weakly coupled parabolic p.d.e. with reaction-diffusion is investigated. The system describes fission gas transfer from grain interior of UO 2 to grain boundaries. The problem is studied in a bounded domain. Using the upper-lower solutions method, two monotone sequences for the finite differences equations are constructed. Reasons are mentioned that allow to affirm that in the proposed functional sector the algorithm converges to the unique solution of the differential system. (author)

  2. EFFECTS OF ALTERNATE ANTIFOAM AGENTS, NOBLE METALS, MIXING SYSTEMS AND MASS TRANSFER ON GAS HOLDUP AND RELEASE FROM NONNEWTONIAN SLURRIES

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, H; Mark Fowley, M; Charles Crawford, C; Michael Restivo, M; Robert Leishear, R

    2007-12-24

    Gas holdup tests performed in a small-scale mechanically-agitated mixing system at the Savannah River National Laboratory (SRNL) were reported in 2006. The tests were for a simulant of waste from the Hanford Tank 241-AZ-101 and featured additions of DOW Corning Q2-3183A Antifoam agent. Results indicated that this antifoam agent (AFA) increased gas holdup in the waste simulant by about a factor of four and, counter intuitively, that the holdup increased as the simulant shear strength decreased (apparent viscosity decreased). These results raised questions about how the AFA might affect gas holdup in Hanford Waste Treatment and Immobilization Plant (WTP) vessels mixed by air sparging and pulse-jet mixers (PJMs). And whether the WTP air supply system being designed would have the capacity to handle a demand for increased airflow to operate the sparger-PJM mixing systems should the AFA increase retention of the radiochemically generated flammable gases in the waste by making the gas bubbles smaller and less mobile, or decrease the size of sparger bubbles making them mix less effectively for a given airflow rate. A new testing program was developed to assess the potential effects of adding the DOW Corning Q2-3183A AFA to WTP waste streams by first confirming the results of the work reported in 2006 by Stewart et al. and then determining if the AFA in fact causes such increased gas holdup in a prototypic sparger-PJM mixing system, or if the increased holdup is just a feature of the small-scale agitation system. Other elements of the new program include evaluating effects other variables could have on gas holdup in systems with AFA additions such as catalysis from trace noble metals in the waste, determining mass transfer coefficients for the AZ-101 waste simulant, and determining whether other AFA compositions such as Dow Corning 1520-US could also increase gas holdup in Hanford waste. This new testing program was split into two investigations, prototypic sparger

  3. Heavy leptons

    International Nuclear Information System (INIS)

    Smith, C.H.L.

    1977-01-01

    The possibility that a new lepton may exist is discussed under the headings; theoretical reasons for the introduction of heavy leptons, classification of heavy leptons (ortho and paraleptons), discrimination between different types of lepton, decays of charged heavy leptons, production of charged heavy leptons (in e + e - storage rings, neutrino production, photoproduction, and hadroproduction), neutral heavy leptons, and hadroleptons. (U.K.)

  4. Flow rate and source reservoir identification from airborne chemical sampling of the uncontrolled Elgin platform gas release

    Science.gov (United States)

    Lee, James D.; Mobbs, Stephen D.; Wellpott, Axel; Allen, Grant; Bauguitte, Stephane J.-B.; Burton, Ralph R.; Camilli, Richard; Coe, Hugh; Fisher, Rebecca E.; France, James L.; Gallagher, Martin; Hopkins, James R.; Lanoiselle, Mathias; Lewis, Alastair C.; Lowry, David; Nisbet, Euan G.; Purvis, Ruth M.; O'Shea, Sebastian; Pyle, John A.; Ryerson, Thomas B.

    2018-03-01

    An uncontrolled gas leak from 25 March to 16 May 2012 led to evacuation of the Total Elgin wellhead and neighbouring drilling and production platforms in the UK North Sea. Initially the atmospheric flow rate of leaking gas and condensate was very poorly known, hampering environmental assessment and well control efforts. Six flights by the UK FAAM chemically instrumented BAe-146 research aircraft were used to quantify the flow rate. The flow rate was calculated by assuming the plume may be modelled by a Gaussian distribution with two different solution methods: Gaussian fitting in the vertical and fitting with a fully mixed layer. When both solution methods were used they compared within 6 % of each other, which was within combined errors. Data from the first flight on 30 March 2012 showed the flow rate to be 1.3 ± 0.2 kg CH4 s-1, decreasing to less than half that by the second flight on 17 April 2012. δ13CCH4 in the gas was found to be -43 ‰, implying that the gas source was unlikely to be from the main high pressure, high temperature Elgin gas field at 5.5 km depth, but more probably from the overlying Hod Formation at 4.2 km depth. This was deemed to be smaller and more manageable than the high pressure Elgin field and hence the response strategy was considerably simpler. The first flight was conducted within 5 days of the blowout and allowed a flow rate estimate within 48 h of sampling, with δ13CCH4 characterization soon thereafter, demonstrating the potential for a rapid-response capability that is widely applicable to future atmospheric emissions of environmental concern. Knowledge of the Elgin flow rate helped inform subsequent decision making. This study shows that leak assessment using appropriately designed airborne plume sampling strategies is well suited for circumstances where direct access is difficult or potentially dangerous. Measurements such as this also permit unbiased regulatory assessment of potential impact, independent of the emitting

  5. Characterizations of purple non-sulfur bacteria isolated from paddy fields, and identification of strains with potential for plant growth-promotion, greenhouse gas mitigation and heavy metal bioremediation.

    Science.gov (United States)

    Sakpirom, Jakkapan; Kantachote, Duangporn; Nunkaew, Tomorn; Khan, Eakalak

    2017-04-01

    This study was aimed at selecting purple non-sulfur bacteria (PNSB) isolated from various paddy fields, including Cd- and Zn-contaminated paddy fields, based on their biofertilizer properties. Among 235 PNSB isolates, strain TN110 was most effective in plant growth-promoting substance (PGPS) production, releasing 3.2 mg/L of [Formula: see text] , 4.11 mg/L of 5-aminolevulinic acid (ALA) and 3.62 mg/L of indole-3-acetic acid (IAA), and reducing methane emission up to 80%. This strain had nifH, vnfG and anfG, which are the Mo, V and Fe nitrogenase genes encoded for key enzymes in nitrogen fixation under different conditions. This strain provided 84% and 55% removal of Cd and Zn, respectively. Another isolate, TN414, not only produced PGPS (1.30 mg/L of [Formula: see text] , 0.94 mg/L of ALA and 0.65 mg/L of IAA), but was also efficient in removing both Cd and Zn at 72% and 74%, respectively. Based on 16S rDNA sequencing, strain TN110 was identified as Rhodopseudomonas palustris, while strain TN414 was Rubrivivax gelatinosus. A combination of TN110 and TN414 could potentially provide a biofertilizer, which is a greener alternative to commercial/chemical fertilizers and an agent for bioremediation of heavy metals and greenhouse gas mitigation in paddy fields. Copyright © 2016 Institut Pasteur. All rights reserved.

  6. Statistical atmospheric inversion of local gas emissions by coupling the tracer release technique and local-scale transport modelling: a test case with controlled methane emissions

    Directory of Open Access Journals (Sweden)

    S. Ars

    2017-12-01

    Full Text Available This study presents a new concept for estimating the pollutant emission rates of a site and its main facilities using a series of atmospheric measurements across the pollutant plumes. This concept combines the tracer release method, local-scale atmospheric transport modelling and a statistical atmospheric inversion approach. The conversion between the controlled emission and the measured atmospheric concentrations of the released tracer across the plume places valuable constraints on the atmospheric transport. This is used to optimise the configuration of the transport model parameters and the model uncertainty statistics in the inversion system. The emission rates of all sources are then inverted to optimise the match between the concentrations simulated with the transport model and the pollutants' measured atmospheric concentrations, accounting for the transport model uncertainty. In principle, by using atmospheric transport modelling, this concept does not strongly rely on the good colocation between the tracer and pollutant sources and can be used to monitor multiple sources within a single site, unlike the classical tracer release technique. The statistical inversion framework and the use of the tracer data for the configuration of the transport and inversion modelling systems should ensure that the transport modelling errors are correctly handled in the source estimation. The potential of this new concept is evaluated with a relatively simple practical implementation based on a Gaussian plume model and a series of inversions of controlled methane point sources using acetylene as a tracer gas. The experimental conditions are chosen so that they are suitable for the use of a Gaussian plume model to simulate the atmospheric transport. In these experiments, different configurations of methane and acetylene point source locations are tested to assess the efficiency of the method in comparison to the classic tracer release technique in coping

  7. Statistical atmospheric inversion of local gas emissions by coupling the tracer release technique and local-scale transport modelling: a test case with controlled methane emissions

    Science.gov (United States)

    Ars, Sébastien; Broquet, Grégoire; Yver Kwok, Camille; Roustan, Yelva; Wu, Lin; Arzoumanian, Emmanuel; Bousquet, Philippe

    2017-12-01

    This study presents a new concept for estimating the pollutant emission rates of a site and its main facilities using a series of atmospheric measurements across the pollutant plumes. This concept combines the tracer release method, local-scale atmospheric transport modelling and a statistical atmospheric inversion approach. The conversion between the controlled emission and the measured atmospheric concentrations of the released tracer across the plume places valuable constraints on the atmospheric transport. This is used to optimise the configuration of the transport model parameters and the model uncertainty statistics in the inversion system. The emission rates of all sources are then inverted to optimise the match between the concentrations simulated with the transport model and the pollutants' measured atmospheric concentrations, accounting for the transport model uncertainty. In principle, by using atmospheric transport modelling, this concept does not strongly rely on the good colocation between the tracer and pollutant sources and can be used to monitor multiple sources within a single site, unlike the classical tracer release technique. The statistical inversion framework and the use of the tracer data for the configuration of the transport and inversion modelling systems should ensure that the transport modelling errors are correctly handled in the source estimation. The potential of this new concept is evaluated with a relatively simple practical implementation based on a Gaussian plume model and a series of inversions of controlled methane point sources using acetylene as a tracer gas. The experimental conditions are chosen so that they are suitable for the use of a Gaussian plume model to simulate the atmospheric transport. In these experiments, different configurations of methane and acetylene point source locations are tested to assess the efficiency of the method in comparison to the classic tracer release technique in coping with the distances

  8. A modified commercial gas chromatograph for the continuous monitoring of the thermal degradation of sunflower oil and off-line solid phase extraction gas-chromatography-mass spectrometry characterization of released volatiles.

    Science.gov (United States)

    Ontañon, I; Sanz, J; Escudero, A; de Marcos, S; Ferreira, V; Galbán, J

    2015-04-03

    A homemade flow cell attached to a commercial Gas Chromatograph equipped with a Flame Ionization Detector (FID) has been designed for the continuous monitoring of volatile compounds released during heating edible oils. Analytical parameters such as mass of sample, temperature and flow rates have been optimized and the obtained results have been compared with the corresponding thermographs from standard TG systems. Results show that under optimum conditions, the profiles of volatiles released upon heating are comparable to the profiles of TG curves, suggesting that the FID based system could be an alternative to TGA. Additionally, volatiles have been retained in a Lichrolut EN(®) resin, eluted and analyzed by Gas Chromatography-Mass Spectrometry. In this case, forty five compounds have been identified (acids, alcohols, alkanes, aldehydes, ketones and furans) and compared with the FID signals, working both in air or nitrogen atmosphere. It has been concluded that the oxidative thermal degradation is prevented in the presence of a nitrogen atmosphere. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    DEFF Research Database (Denmark)

    Christel, Wibke; Zhu, Kun; Hoefer, Christoph

    2016-01-01

    processes and fixation in the residue sphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing...... on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids...

  10. Heated uranium tetrafluoride target system to release non-rare gas fission products for the TRISTAN isotope separator

    International Nuclear Information System (INIS)

    Gill, R.L.

    1977-10-01

    Off-line experiments indicated that fluorides of As, Se, Br, Kr, Zr, Nb, Mo, Tc, Ru, Sb, Te, I and Xe could be volatilized, but except for Br, Kr, I and Xe, none of these elements were observed after mass separation in the on-line experiments. The results of the on-line experiments indicated a very low level of hydride contamination at ambient temperature and consequently, uranium tetrafluoride replaced uranyl stearate as the primary gaseous fission product target. Possible reasons for the failure of the heated target system to yield non-rare gas activities are discussed and suggestions for designing a new heated target system are presented

  11. Application of modern online instrumentation for chemical analysis of gas and particulate phases of exhaust at the European Commission heavy-duty vehicle emission laboratory.

    Science.gov (United States)

    Adam, T W; Chirico, R; Clairotte, M; Elsasser, M; Manfredi, U; Martini, G; Sklorz, M; Streibel, T; Heringa, M F; Decarlo, P F; Baltensperger, U; De Santi, G; Krasenbrink, A; Zimmermann, R; Prevot, A S H; Astorga, C

    2011-01-01

    The European Commission recently established a novel test facility for heavy-duty vehicles to enhance more sustainable transport. The facility enables the study of energy efficiency of various fuels/scenarios as well as the chemical composition of evolved exhaust emissions. Sophisticated instrumentation for real-time analysis of the gas and particulate phases of exhaust has been implemented. Thereby, gas-phase characterization was carried out by a Fourier transform infrared spectrometer (FT-IR; carbonyls, nitrogen-containing species, small hydrocarbons) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-TOFMS; monocyclic and polycyclic aromatic hydrocarbons). For analysis of the particulate phase, a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS; organic matter, chloride, nitrate), a condensation particle counter (CPC; particle number), and a multiangle absorption photometer (MAAP; black carbon) were applied. In this paper, the first application of the new facility in combination with the described instruments is presented, whereby a medium-size truck was investigated by applying different driving cycles. The goal was simultaneous chemical characterization of a great variety of gaseous compounds and particulate matter in exhaust on a real-time basis. The time-resolved data allowed new approaches to view the results; for example, emission factors were normalized to time-resolved consumption of fuel and were related to emission factors evolved during high speeds. Compounds could be identified that followed the fuel consumption, others showed very different behavior. In particular, engine cold start, engine ignition (unburned fuel), and high-speed events resulted in unique emission patterns.

  12. Microbial weathering processes after release of heavy metals and arsenic from fluvial tailing deposits; Mikrobielle Verwitterungsprozesse bei der Freisetzung von Schwermetallen und Arsen aus fluvialen Tailingablagerungen

    Energy Technology Data Exchange (ETDEWEB)

    Willscher, S. [Technische Univ. Dresden (Germany). Fak. fuer Forst, Geo und Hydrowissenschaften, Inst. fuer Abfallwirtschaft und Altlasten

    2006-07-01

    Microbial processes play an important role in global metal cycles. The microbial weathering of mineral surfaces, including deposited anthropogenic mineral remainders, is a natural occurring process, taking place on uncovered dump surfaces as well as in deeper zones of dumps. Such weathering processes also occur in metal contaminated soils and sediments. In this work, a sulfidic fluvial tailing sediment was investigated for its acidity and salinity generating potential and the subsequent mobilisation of heavy metals, generated by biogeochemical processes. The long-term risks of such a deposit were evaluated. Unstabilised deposits of such materials can generate a considerable contamination of the surrounding ground and surface water. It could be shown in the experiments that in acid generating dumps and tailing materials besides the well known acidophilic autotrophs also acidotolerant heterotrophic microorganisms play a role in the mobilisation of metals. (orig.)

  13. Diagnosis of high-intensity pulsed heavy ion beam generated by a novel magnetically insulated diode with gas puff plasma gun.

    Science.gov (United States)

    Ito, H; Miyake, H; Masugata, K

    2008-10-01

    Intense pulsed heavy ion beam is expected to be applied to materials processing including surface modification and ion implantation. For those applications, it is very important to generate high-purity ion beams with various ion species. For this purpose, we have developed a new type of a magnetically insulated ion diode with an active ion source of a gas puff plasma gun. When the ion diode was operated at a diode voltage of about 190 kV, a diode current of about 15 kA, and a pulse duration of about 100 ns, the ion beam with an ion current density of 54 A/cm(2) was obtained at 50 mm downstream from the anode. By evaluating the ion species and the energy spectrum of the ion beam via a Thomson parabola spectrometer, it was confirmed that the ion beam consists of nitrogen ions (N(+) and N(2+)) of energy of 100-400 keV and the proton impurities of energy of 90-200 keV. The purity of the beam was evaluated to be 94%. The high-purity pulsed nitrogen ion beam was successfully obtained by the developed ion diode system.

  14. The Existence of Heavy Metals such as Pb, Cd, Fe, and Cu in Hair Samples from Gas Station Worker at Yogyakarta Special District

    International Nuclear Information System (INIS)

    Supriyanto, C.; Zainul Kamal; Samin

    2002-01-01

    The monitoring of heavy metals existence such as Pb, Cd, Fe, and Cu in hair samples from gas station worker has been carried out with atomic absorption spectrometry method. The initial preparation of sample were done by immersing them in alcohol over night, after they were dried then they were digested using the teflon bomb digester at the temperature at 150 o C for 3 hours. The content of Pb, Cd, Fe, and Cu in were determined with calibration standard curve method. The content of Pb obtained at hair samples in the range of time at 20 years tend to increase. If it was correlated to the worker who has been working, there was no significant different from the worker who has been working for 20 years there was no significant different. While the content of Cu in sample at range time 20 years showed the significant different if it was correlated to the worker who has been working. The validity of method was tested with CRM Human Hair GBW 07601 from IAEA showed that the content of Fe and Cu were in the certified range of CRM. (author)

  15. Gas Release Behavior of Cu-TiH2 Composite Powder and Its Application as a Blowing Agent to Fabricate Aluminum Foams with Low Porosity and Small Pore Size

    Science.gov (United States)

    Cheng, Ying; Li, Yanxiang; Chen, Xiang; Liu, Zhiyong; Zhou, Xu; Wang, Ningzhen

    2018-03-01

    Compared to traditional pore structure with high porosity (≥ 80 pct) and large pore size (≥ 3 mm), aluminum foams with low porosity (60 to 70 pct) and small pore size (≤ 2 mm) possess higher compressive property and formability. In order to achieve the goal of reducing pore size, Cu-TiH2 composite powder prepared by ball milling preoxidized TiH2 with Cu powder was used as a blowing agent. Its gas release behavior was characterized by thermogravimetric analysis and differential scanning calorimetry. The results show that the ball milling treatment can advance the gas release process and slow the gas release rate at the same time. All these changes are favorable to the reduction of porosity and pore size. Such Cu-TiH2 composite powder provides an alternative way to fabricate aluminum foams with low porosity and small pore size.

  16. Gas Release Behavior of Cu-TiH2 Composite Powder and Its Application as a Blowing Agent to Fabricate Aluminum Foams with Low Porosity and Small Pore Size

    Science.gov (United States)

    Cheng, Ying; Li, Yanxiang; Chen, Xiang; Liu, Zhiyong; Zhou, Xu; Wang, Ningzhen

    2018-06-01

    Compared to traditional pore structure with high porosity (≥ 80 pct) and large pore size (≥ 3 mm), aluminum foams with low porosity (60 to 70 pct) and small pore size (≤ 2 mm) possess higher compressive property and formability. In order to achieve the goal of reducing pore size, Cu-TiH2 composite powder prepared by ball milling preoxidized TiH2 with Cu powder was used as a blowing agent. Its gas release behavior was characterized by thermogravimetric analysis and differential scanning calorimetry. The results show that the ball milling treatment can advance the gas release process and slow the gas release rate at the same time. All these changes are favorable to the reduction of porosity and pore size. Such Cu-TiH2 composite powder provides an alternative way to fabricate aluminum foams with low porosity and small pore size.

  17. The Bubble Box: Towards an Automated Visual Sensor for 3D Analysis and Characterization of Marine Gas Release Sites

    Directory of Open Access Journals (Sweden)

    Anne Jordt

    2015-12-01

    Full Text Available Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane from the ocean floor. Here, single-camera based methods for bubble stream observation have become an important tool, as they help estimating flux and bubble sizes under certain assumptions. However, they record only a projection of a bubble into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical bubbles. The unknown distance of the bubble to the camera (making it appear larger or smaller than expected as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor bubble box that overcomes these limitations, as it observes bubbles from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting