WorldWideScience

Sample records for activation decay heat

  1. Decay heat calculations for reactors

    Estimation of release of energy (decay heat) over an extended period of time after termination of neutron induced fission is necessary for determining the heat removal requirements when the reactor is shutdown, and for fuel storage and transport facilities as well as for accident studies. The method of decay heat estimation relies on the measurements over practical time intervals as well as on calculation for predictions over very long time intervals. Neutron cross-sections, fission yields and decay data together with operational history are the basic inputs to such. A code used to calculate decay heat would require to generate isotopic inventory that would be present at the shutdown based on operational history of the reactor and follow up the decay over an extended period of time. Aspects of decay heat estimation based on standards like ANS 5.1 and by fuel cycle analysis codes shall be discussed. A Fuel Cycle Analysis Code, ADWITA (Activation, Decay, Waste Incineration and Transmutation Analysis) which can generate inventory based on irradiation history and calculate radioactivity and decay heat for extended period of cooling, has been written. The method and data involved in Fuel Cycle Analysis Code ADWITA and some results obtained shall also be presented. (author)

  2. Evaluation of induced activity, decay heat and dose rate distribution after shutdown in ITER

    Maki, Koichi [Hitachi Ltd., Ibaraki (Japan). Hitachi Research Lab.; Satoh, Satoshi; Hayashi, Katsumi; Yamada, Koubun; Takatsu, Hideyuki; Iida, Hiromasa

    1997-03-01

    Induced activity, decay heat and dose rate distributions after shutdown were estimated for 1MWa/m{sup 2} operation in ITER. The activity in the inboard blanket one day after shutdown is 1.5x10{sup 11}Bq/cm{sup 3}, and the average decay heating rate 0.01w/cm{sup 3}. The dose rate outside the 120cm thick concrete biological shield is two order higher than the design criterion of 5{mu}Sv/h. This indicates that the biological shield thickness should be enhanced by 50cm in concrete, that is, total thickness 170cm for workers to enter the reactor room and to perform maintenance. (author)

  3. THIDA-2: an advanced code system for calculation of transmutation, activation, decay heat and dose rate

    In a D-T burning fusion reactor, the radioactivity induced by the 14 MeV neutrons causes many problems. It limits personnel access to the reactor during shutdown, generates decay heat and produces radwastes. A code system THIDA had been developed in 1978 to calculate the radioactivity and dose rate around a fusion device. The THIDA system consisted of the followings: one- and two-dimensional discrete ordinates radiation transport codes; induced activity calculation code; three libraries for transmutation and decay chain data, transmutation cross sections and delayed gamma-ray emission data. The present report gives a complete description of THIDA-2, a new advanced version of the THIDA system which has the following major improvements: 1. Capability to treat three-dimensional calculation models by the use of a Monte Carlo transport code. 2. Accurate decay heat calculation following the transport of delayed gamma rays. 3. Simplification of the data input process by the use of free format scheme and closer coupling between the radiation transport codes and the induced activity calculation code. 4. Self-descriptive output format and additional plotter output. 5. Capability to calculate problems requiring larger core memory by the use of variable dimension. (author)

  4. Decay Heat Code Validation Activities at ORNL: Supporting Expansion of NRC Regulatory Guide 3.54

    Oak Ridge National Laboratory (ORNL) has a long history of involvement in the development and validation of the ORIGEN series of isotope summation codes and nuclear data libraries, widely recognized and used to predict the decay heat for spent nuclear fuel. In particular, the ORIGEN-S code, the depletion/decay module of the SCALE code system, has been extensively validated using experimental isotopic assay data and decay heat measurements for commercial spent fuel. This work was used in the development of the technical basis for NRC Regulatory Guide 3.54 on spent fuel decay heat. The bulk of the experimental data used to validate spent fuel decay heat predictions are from programs of the 1970s and 1980s and consequently involve older-design fuel assemblies with a relatively low enrichment and burnup. This has led to a situation where the spent fuel now being discharged from operating reactors extends well beyond the regime of the experimental data and area of code applicability based on the data. The absence of validation data for modern fuel designs has potentially serious consequences for decay heat predictions in terms of added safety factors to account for larger uncertainties and lower volumetric transport and storage capacities

  5. Consolidated fuel decay heat calculations

    Wittekind, W.D.

    1994-06-24

    The radiological decay heat generated from all irradiated fuel presently in K East (KE) and K West (KW) Basins was calculated in support of consolidated fuel storage. There are four sources of heat inflow into the fuel storage basins: (1) radiological decay heat from irradiated fuel; (2) mechanical heat from operating machinery (e.g., pumps); (3) heat flow from surroundings (mainly the ground through the concrete walls into the basin water if it is maintained below ambient); and (4) exothermic chemical reactions of uranium oxidation (although at basin temperatures this reaction rate is slow). This report details the radiological decay heat from irradiated fuel source in the K basins. Decay heat calculations using ORIGEN2 (Wittekind 1994 and Schmittroth 1993) for irradiated fuel presently (April 1994) in KE and KW Basins gave results for January 31 of each year.

  6. Data for decay Heat Predictions

    These proceedings of a specialists' meeting on data for decay heat predictions are based on fission products yields, on delayed neutrons and on comparative evaluations on evaluated and experimental data for thermal and fast fission. Fourteen conferences were analysed

  7. Material composition and nuclear data libraries' influence on nickel-chromium alloys activation evaluation: a comparison with decay heat experiments

    The paper presents the activation analyses on Inconel-600 nickel-chromium alloy. Three activation data libraries, namely the EAF-4.1, the EAF-97 and the FENDL/A-2, and the FENDL/D-2 decay data library, have been used to perform the calculation with the European activation code ANITA-4/M. The neutron flux distribution into the material samples was provided by JAERI as results of 3D Monte-Carlo MCNP transport code experiment simulation. A comparison with integral decay heat measurement performed at the Fusion Neutronics Source (FNS), JAERI, Tokai, Japan, is used to validate the computational approach. The calculation results are given and discussed. The impact of the material composition, including impurities, on the decay heat of samples irradiated in fusion-like neutron spectra is assessed and discussed. The discrepancies calculations-experiments are within the experimental errors, that is between 6% and 10%, except for the short cooling times (less than 40 min after the end of irradiation). To improve calculation consistency with the experimental results, the knowledge of the material impurities content is mandatory

  8. Material composition and nuclear data libraries' influence on nickel-chromium alloys activation evaluation: a comparison with decay heat experiments

    Cepraga, D G

    2000-01-01

    The paper presents the activation analyses on Inconel-600 nickel-chromium alloy. Three activation data libraries, namely the EAF-4.1, the EAF-97 and the FENDL/A-2, and the FENDL/D-2 decay data library, have been used to perform the calculation with the European activation code ANITA-4/M. The neutron flux distribution into the material samples was provided by JAERI as results of 3D Monte-Carlo MCNP transport code experiment simulation. A comparison with integral decay heat measurement performed at the Fusion Neutronics Source (FNS), JAERI, Tokai, Japan, is used to validate the computational approach. The calculation results are given and discussed. The impact of the material composition, including impurities, on the decay heat of samples irradiated in fusion-like neutron spectra is assessed and discussed. The discrepancies calculations-experiments are within the experimental errors, that is between 6% and 10%, except for the short cooling times (less than 40 min after the end of irradiation). To improve calcul...

  9. Decay Heat Removal System of Monju

    MONJU has three decay heat removal systems. The intermediate heat exchanger of the decay heat removal system is incorporated within the main IHX shell, and the heat from the secondary system is rejected to the air. Forced circulation is adopted for both primary and secondary coolant, though natural circulation capability is designed into the plant itself. Feasibility of rejecting the decay heat through steam plant is also being studied. In this paper, MONJU's decay heat removal system design, operational procedures, and the considerations behind the concept will be presented. (author)

  10. Passive decay heat removal during shutdown

    During shutdown the decay heat in commercial Boiling Water Reactors is removed from the core region by active and redundant pump/heat exchanger-systems which are, in addition, supported by emergency power. To study the capability of the newly developed emergency condensers to remove energy produced within the core region to a large water pool outside the Reactor Pressure Vessel by natural convection, a related test in the NOKO facility as performed. The pressure vessel in the NOKO facility has been flooded above the inlet line to the emergency condenser and heated up to about 100 deg. C. The natural circulation resulted in a cool down of the water within the pressure vessel. With two specially designed grids equipped with up to 12 thermocouples the temperature fields in two cross sections were measured: no plume-effect was identified. The vertical temperature profile was measured with thermocouples. The test showed that decay heat could be removed some time after scram to an outside pool by natural convection processes: the time after scram depends on the emergency condenser heat exchange area. (author)

  11. Heat Transfer Characteristics of SiC-coated Heat Pipe for Passive Decay Heat Removal

    Kim, Kyung Mo; Kim, In Guk; Jeong, Yeong Shin; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    The main concern with the Fukushima accident was the failure of active and passive core cooling systems. The main function of existing passive decay heat removal systems is feeding additional coolant to the reactor core. Thus, an established emergency core cooling system (ECCS) cannot operate properly because of impossible depressurization under the station blackout (SBO) condition. Therefore, a new concept for passive decay heat removal system is required. In this study, an innovative hybrid control rod concept is considered for passive in-core decay heat removal that differs from the existing direct vessel injection core cooling system and passive auxiliary feedwater system (PAFS). The heat transfer between the evaporator and condenser sections occurs by phase change of the working fluid and capillary action induced by wick structures installed on the inner wall of the heat pipe. In this study, a hybrid control rod is developed to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and control rod. Previous studies on enhancing the heat removal capacity of heat pipes used nanofluids, self-rewetting fluids, various wick structures and condensers. Many studies have examined the thermal performances of heat pipes using various nanofluids. They concluded that the enhanced thermal performance of the heat pipe using nanofluids is due to nanoparticle deposition on the wick structures. Thus, the wick structure of heat pipes has been modified by nanoparticle deposition to enhance the heat removal capacity. However, previous studies used relatively small heat pipes and narrow ranges of heat loads. The environment of a nuclear reactor is very specific, and the decay heat produced by fission products after shutdown is relatively large. Thus, this study tested a large-scale heat pipe over a wide range of power. The concept of a hybrid heat pipe for an advanced in-core decay heat removal system was introduced for complete

  12. Estimation of decay heat in fusion DEMO reactor

    The decay heat of activated materials is important in safety assessment of fusion DEMO reactor against loss of coolant-flow accidents. Decay heat for reactor main components of the SlimCS DEMO reactor was studied with a one-dimensional code THIDA-2. The reactor main components consist of the inboard (IB) blanket module, outboard (OB) blanket module and divertor. For a reactor with a fusion output of 3.0 GW, the decay heat of IB blanket, OB blanket, divertor and radiation shield were estimated to be as high as 8.6 MW, 30.9 MW, 10.6 MW and 1.8 MW, respectively, immediately after the shutdown of operation. The total decay heat was as high as 52 MW immediately after the shutdown and 3.1 MW one month later. The blanket produces the largest portion of decay heat, about 76%. (author)

  13. Safety characteristics of decay heat removal systems

    Safety features of the decay heat removal systems including power sunply and final heat sink are described. A rather high reliability and an utmost degree of independence from energy supply are goals to be attained in the design of the European Fast Reactor (EFR) decay heat removal scheme. Natural circulation is an ambitious design goal for EFR. All the considerations are performed within the frame of risk minimization

  14. Development of limiting decay heat values

    A number of tools are used in the assessment of decay heat during an outage of the CANDU-6. Currently, the technical basis for all of these tools is 'CANDU Channel Decay Power', Reference 1. The methods used in that document were limited to channel decay powers. However, for most outage support analysis, decay heat limits are based on bundle heats. Since the production of that document in 1977, new versions of codes, and updates of general-purpose and CANDU-specific libraries have become available. These tools and libraries have both a more formal technical basis than Reference 1, and also a more formal validation base. Using these tools it is now possible to derive decay heat with more specific input parameters, such as fuel composition, heat per unit of fuel, and irradiation history, and to assign systematically derived uncertainty allowances to such decay heat values. In particular, we sought to examine a broad range of likely bundle histories, and thus establish a set of limiting bundle decay beat values, that could serve as a bounding envelope for use in Nuclear Safety Analysis. (author)

  15. Heat Kernels, Smoothness Estimates and Exponential Decay

    Boggess, Albert; Raich, Andrew

    2010-01-01

    In this article, we establish Gaussian decay for the Box_b-heat kernel on polynomial models in C^2. Our technique attains the exponential decay via a partial Fourier transform. On the transform side, the problem becomes finding quantitative smoothness estimates on a heat kernel associated to the weighted dbar-operator on L^2(C). The bounds are established with Duhamel's formula and careful estimation.

  16. Decay heat studies for nuclear energy

    Algora, A.; Jordan, D.; Taín, J. L.; Rubio, B.; Agramunt, J.; Caballero, L.; Nácher, E.; Perez-Cerdan, A. B.; Molina, F.; Estevez, E.; Valencia, E.; Krasznahorkay, A.; Hunyadi, M. D.; Gulyás, J.; Vitéz, A.; Csatlós, M.; Csige, L.; Eronen, T.; Rissanen, J.; Saastamoinen, A.; Moore, I. D.; Penttilä, H.; Kolhinen, V. S.; Burkard, K.; Hüller, W.; Batist, L.; Gelletly, W.; Nichols, A. L.; Yoshida, T.; Sonzogni, A. A.; Peräjärvi, K.

    2014-01-01

    The energy associated with the decay of fission products plays an important role in the estimation of the amount of heat released by nuclear fuel in reactors. In this article we present results of the study of the beta decay of some refractory isotopes that were considered important contributors to the decay heat in reactors. The measurements were performed at the IGISOL facility of the University of Jyväskylä, Finland. In these studies we have combined for the first time a Penning trap (JYFLTRAP), which was used as a high resolution isobaric separator, with a total absorption spectrometer. The results of the measurements as well as their consequences for decay heat summation calculations are discussed.

  17. Decay heat of fast reactor spent fuel

    Decay heat from JOYO Mk-II spent fuel subassemblies was measured to obtain experimental data and to improve the accuracy of related calculations. The measurement was taken in the JOYO spent fuel storage pond. The fuel burn-up was approximately 66 GWd/t and the cooling time was between 40 and 385 days. The decay heat was calculated with the ORIGEN2 code using the JENDL-3.2 cross section library and the JNDC-V2 decay data and fission yield data library. The fuel power used as an input to ORIGEN2 was calculated by the MAGI core management code system. The ratios between calculated and experimental values were between 0.94 and 0.89 and decreased with a longer cooling time. This systematic discrepancy is not fully understood, but the change with cooling time appears to be due to the actinide decay heat uncertainty. This indicated that cross sections of actinides are important to evaluate decay heat accurately. (author)

  18. Study on diverse passive decay heat removal approach and principle

    Decay heat removal in post-accident is one of the most important aspects concerned in the reactor safety analysis. Passive decay heat removal approach is used to enhance nuclear safety. In advanced reactors, decay heat is removed by multiple passive heat removal paths through core to ultimate heat sink by passive residual heat removal system, passive injection system, passive containment cooling system and so on. Various passive decay heat removal approaches are summarized in this paper, the common features and differences of their heat removal paths are analyzed, and the design principle of passive systems for decay heat removal is discussed. It is found that. these decay heat removal paths is combined by some basic heat transfer processes, by the combination of these basic processes, diverse passive decay heat removal approach or system design scheme can be drawn. (authors)

  19. Fission product decay heat for thermal reactors

    Dickens, J. K.

    1979-01-01

    In the past five years there have been new experimental programs to measure decay heat (i.e., time dependent beta- plus gamma-ray energy release rates from the decay of fission products) following thermal-neutron fission of /sup 235/U, /sup 239/Pu, and /sup 241/Pu for times after fission between 1 and approx. 10/sup 5/ sec. Experimental results from the ORNL program stress the very short times following fission, particularly in the first few hundred sec. Complementing the experimental effort, computer codes have been developed for the computation of decay heat by summation of calculated individual energies released by each one of the fission products. By suitably combining the results of the summation calculations with the recent experimental results, a new Decay Heat Standard has been developed for application to safety analysis of operations of light water reactors. The new standard indicates somewhat smaller energy release rates than those being used at present, and the overall uncertainties assigned to the new standard are much smaller than those being used at present.

  20. Applications of TAGS data in beta decay energies and decay heat calculations

    Pham, N. S.; 片倉 純一

    2007-01-01

    The recent data of beta-decay intensity measured by using the total absorption gamma-ray spectrometer (TAGS), for several fission products (FP), has been applied for calculations of the average energies and spectra, and decay heat summations. The calculations were performed based on the Gross theory of beta decay, in which the beta strength functions were experimentally derived from TAGS data. The deviations of decay heat power predictions from the original decay data of JENDL Decay Data File...

  1. Jeff-3 and decay heat calculations

    The decay heat power, i.e. the residual heat generated by irradiated nuclear fuels, is a significant parameter to define the power of a reactor. A good evaluation of this power depends both on the accuracy of the processing algorithm and on the quality of the physical data used. This report describes the steps carried out, ranging from tests of consistency to the validation by calculations - experiments comparisons, allowing to choose the validated nuclear data. We have compared the Jeff-3 evaluation (only the file 8 containing decay data) with the Jeff-2.2 and Endf/B7.O evaluations through the computation of residual power. It appears that the residual powers computed by the DARWIN code from Jeff-3.1.1 data for short times agree more with experimental data. There is a slight discrepancy (∼ 2%) between Jeff-3.1 and Jeff-3.1.1 on the total residual power computed for PWR UO2 fuel. For long decay times the discrepancy is more significant between Jeff-3.1.1 and Jeff-2 on the computation of detailed residual powers because some prevailing isotopes have more formation channels taken into account in Jeff-3 and Jeff-3.1.1 than in Jeff-2

  2. Study on diverse passive decay heat removal approach

    One of the most important principles for nuclear safety is the decay heat removal in accidents. Passive decay heat removal systems are extremely helpful to enhance the safety. In currently design of many advanced nuclear reactors, kinds of passive systems are proposed or developed, such as the passive residual heat removal system, passive injection system, passive containment cooling system. These systems provide entire passive heat removal paths from core to ultimate heat sink. Various kinds of passive systems for decay heat removal are summarized; their common features or differences on heat removal paths and design principle are analyzed. It is found that, these passive decay heat removal paths are similarly common on and connected by several basic heat transfer modes and steps. By the combinations or connections of basic modes and steps, new passive decay heat removal approach or diverse system can be proposed. (authors)

  3. Experimental validation of decay heat calculations for ITER

    This article reports an international benchmark exercise to determine nuclear data and activation code uncertainties in the context of decay heat projections for ITER, the subject of a workshop, held a the ITER San Diego, Joint Work Site, October 2-3, 1997, under a Task Agreement between JCT and the Japanese Home Team. In view of the importance of the new results, JCT opened this meeting to other Home Teams to allow interested specialists to participate if they wish

  4. Decay heat experiment and validation of calculation code systems for fusion reactor

    Although accurate estimation of decay heat value is essential for safety analyses of fusion reactors against loss of coolant accidents and so on, no experimental work has been devoted to validating the estimation. Hence, a decay heat measurement experiment was performed as a task (T-339) of ITER/EDA. A new detector, the Whole Energy Absorption Spectrometer (WEAS), was developed for accurate and efficient measurements of decay heat. Decay heat produced in the thirty-two sample materials which were irradiated by 14-MeV neutrons at FNS/JAERI were measured with WEAS for a wide cooling time period from 1 min to 400 days. The data presently obtained were the first experimental decay heat data in the field of fusion. Validity of decay heat calculation codes of ACT4 and CINAC-V4, activation cross section libraries of FENDL/A-2.0 and JENDL Activation File, and decay data was investigated through analyses of the experiment. As a result, several points that should be modified were found in the codes and data. After solving the problems, it was demonstrated that decay heat valued calculated for most of samples were in good agreement with the experimental data. Especially for stainless steel 316 and copper, which were important materials for ITER, decay heat could be predicted with accuracy of ±10%. (author)

  5. Decay heat experiment and validation of calculation code systems for fusion reactor

    Maekawa, Fujio; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Wada, Masayuki

    1999-10-01

    Although accurate estimation of decay heat value is essential for safety analyses of fusion reactors against loss of coolant accidents and so on, no experimental work has been devoted to validating the estimation. Hence, a decay heat measurement experiment was performed as a task (T-339) of ITER/EDA. A new detector, the Whole Energy Absorption Spectrometer (WEAS), was developed for accurate and efficient measurements of decay heat. Decay heat produced in the thirty-two sample materials which were irradiated by 14-MeV neutrons at FNS/JAERI were measured with WEAS for a wide cooling time period from 1 min to 400 days. The data presently obtained were the first experimental decay heat data in the field of fusion. Validity of decay heat calculation codes of ACT4 and CINAC-V4, activation cross section libraries of FENDL/A-2.0 and JENDL Activation File, and decay data was investigated through analyses of the experiment. As a result, several points that should be modified were found in the codes and data. After solving the problems, it was demonstrated that decay heat valued calculated for most of samples were in good agreement with the experimental data. Especially for stainless steel 316 and copper, which were important materials for ITER, decay heat could be predicted with accuracy of {+-}10%. (author)

  6. Experimental Investigation on Decay Heat Removal System of CEFR

    2001-01-01

    The decay heat exists in a relative long time period after reactor shut down. The decay heat is removed by the decay heat removal system (DHRS).The manager of CEFR demanded that experiments should be carried out to make sure that natural circulation could be established under the conditions of < 1.0 percent of the normal power. Experiments are therefore performed under the heating power of 2, 3, 4, 6 and 8.5 kW respectively. The measured temperature in the hot plenum will be used to validate the computer codes. Moreover,

  7. Decay heat calculation an international nuclear code comparison

    The results of an international code comparison on decay heat are presented and discussed. Participants from more than ten laboratories calculated, using the same input data, decay heat for thirteen cooling times between 1 and 1013 sec. Two irradiation cases were proposed: fission pulse and 3x107 seconds of irradiation of 235U fuel. The results are analysed and compared. This inter-comparison shows that, if the same input data are given, most of the codes give very similar results for the decay heat and consequently also for the fission product contribution

  8. Consistency among integral measurements of aggregate decay heat power

    Takeuchi, H.; Sagisaka, M.; Oyamatsu, K.; Kukita, Y. [Nagoya Univ. (Japan)

    1998-03-01

    Persisting discrepancies between summation calculations and integral measurements force us to assume large uncertainties in the recommended decay heat power. In this paper, we develop a hybrid method to calculate the decay heat power of a fissioning system from those of different fissioning systems. Then, this method is applied to examine consistency among measured decay heat powers of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U and {sup 239}Pu at YAYOI. The consistency among the measured values are found to be satisfied for the {beta} component and fairly well for the {gamma} component, except for cooling times longer than 4000 s. (author)

  9. LWR decay heat calculations using a GRS improved ENDF/B-6 based ORIGEN data library

    The known ORNL ORIGEN code is widely spread over the world for inventory, activity and decay heat tasks and is used stand-alone or implemented in activation, shielding or burn-up systems. More than 1000 isotopes with more than six coupled neutron capture and radioactive decay channels are handled simultaneously by the code. The characteristics of the calculated inventories, e.g., masses, activities, neutron and photon source terms or the decay heat during short or long decay time steps are achieved by summing over all isotopes, characterized in the ORIGEN libraries. An extended nuclear GRS-ORIGENX data library is now developed for practical appliance. The library was checked for activation tasks of structure material isotopes and for actinide and fission product burn-up calculations compared with experiments and standard methods. The paper is directed to the LWR decay heat calculation features of the new library and shows the differences of dynamical and time integrated results of Endf/B-6 based and older Endf/B-5 based libraries for decay heat tasks compared to fission burst experiments, ANS curves and some other published data. A multi-group time exponential evaluation is given for the fission burst power of 235U, 238U, 239Pu and 241Pu, to be used in quick LWR reactor accident decay heat calculation tools. (authors)

  10. Decay heat measurement of fusion related materials in an ITER-like neutron field

    Morimoto, Y.; Ochiai, K.; Maekawa, F.; Wada, M.; Nishitani, T.; Takeuchi, H.

    2002-12-01

    Decay heat is one of the most important factors for the safety aspect of ITER. Especially, the prediction of decay heat with an uncertainty less than 15% for the three most important materials, i.e., copper, type-316 stainless steel (SS316) and tungsten, is strongly requested by designers of ITER. To provide experimental decay heat data needed for validation of decay heat calculations for SS316 and copper, an experiment was conducted as the ITER/EDA task T-426. An ITER-like neutron field was constructed, and decay heat source distributions in thick copper and SS316 plates were measured with the whole energy absorption spectrometer. The measured decay heat distributions in the thick sample plates were compared with the predicted values by MCNP calculations. It was found that the use of an effective activation cross-section calculated by MCNP was needed to consider the self-shielding effects and, for both cases, MCNP calculations could predict the decay heat adequately.

  11. Gas-Cooled Fast Reactor (GFR) Decay Heat Removal Concepts

    K. D. Weaver; L-Y. Cheng; H. Ludewig; J. Jo

    2005-09-01

    Current research and development on the Gas-Cooled Fast Reactor (GFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFCI) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GFR: a helium-cooled, direct power conversion system that will operate with an outlet temperature of 850ºC at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in participating in research related to the development of the GFR. These are Euratom (European Commission), France, Japan, South Africa, South Korea, Switzerland, and the United Kingdom. Of these, Euratom (including the United Kingdom), France, and Japan have active research activities with respect to the GFR. The research includes GFR design and safety, and fuels/in-core materials/fuel cycle projects. This report is a compilation of work performed on decay heat removal systems for a 2400 MWt GFR during this fiscal year (FY05).

  12. Proliferation resistance of plutonium based on decay heat

    Proliferation resistance of plutonium can be enhanced by increasing the decay heat of plutonium. For example, it can be enhanced by increasing the isotopic fraction of 238Pu, which has the largest decay heat among plutonium isotopes, produced by transmutation of Minor Actinides (Protected Plutonium Production: P3). In the present paper, proliferation resistance of plutonium was evaluated based on decay heat with physical assessment model. As a summary of the evaluation, new criteria to evaluate proliferation resistance of plutonium based on its isotopic composition from the view point of decay heat were suggested. The present methodology and the criteria were applied to evaluate the impact of P3 by the transmutation of Minor Actinides in fast breeder reactor blanket on proliferation resistance of plutonium. (author)

  13. Method for removal of decay heat of radioactive substances

    In this process, the decay heat from radioactive substances is removed by means of a liquid carried in the coolant loop. The liquid is partially evaporated by the decay heat. The steam is used to drive the liquid through the loop. When a static pressure level equivalent to the pressure drop in the loop is exceeded, the steam is separated from the liquid, condensed, and the condensate is reunited with the return flow of liquid for partial evaporation. (orig.)

  14. Decay heat analysis of MNSR reactor core using ORIGEN-2 code

    Highlights: • Analysis of the decay heat parameters of the MNSR reactor was performed using the ORIGEN-2 code. • A new one-group cross-section data base of the ORlGEN-2 computer code for the MNSR was developed. • It is recommended to adopt the results of the ORIGIEN-2 code for future reactor safety analysis of MNSR. - Abstract: The knowledge of the decay heat of nuclear fuel is necessary for performing the reactor safety analysis, determining the heating load in fuel pools, shielding requirements on fuel discharge and transport routes when irradiated reactor fuel is transferred from the reactor, via some intermediate storage location, to the final disposal or the chemical reprocessing plant. In this study, analysis of the decay heat parameters of the Miniature Neutron Source Reactor (MNSR) including radioactivity, decay heat and the isotopic mass variation with time since reactor shutdown for the potential Low Enriched Uranium (LEU) (UO2-Zircaloy and U3Si-Al) and the standard Highly Enriched Uranium (HEU) (HEU-Al4) cores has been performed using the ORIGEN-2 code. For this purpose, a new one-group cross-section data base of the ORlGEN-2 computer code for the MNSR with LEU and HEU fuels has been developed using the MCNP-4C code. The variation of fission products, actinides and daughters and activation products with post shutdown time for the standard core and the potential LEU cores have been considered in the analysis of the decay heat power resources. It was found that, all the three types of MNSR fuels show close agreement in the total decay heat, which is mainly due to the fission products. This behavior continued for about 1.0E05 days. After this time, the fission products decay heat became comparable with the corresponding actinides decay heat in which the standard HEU UAl4-Al fuel showed the smallest decay heat values while the potential LEU-UO2 fuel had the highest decay heat followed by the LEU-U3Si fuel. The time variation of the total radioactivity

  15. Development of passive decay heat removal system PDRC

    One of the most important tasks in a successful design of a nuclear power plant is the demonstration of safe and reliable decay heat removal (DHR). In order to assure a plant safety, a safety grade DHR system, PDRC (passive decay heat removal circuit), has been developed to cope with the design basis events in KALIMER 600. The PDRX employs an innovative design concept distinct from conventional sodium cooled fast reactor designs currently being developed or operated in the world. An operational reliance of the PDRC system can be remarkably enhanced by excluding either any operator's action or active components operated by an external power supply or actuation signal. Based on the established design concept, system design methodologies have been developed and its performance analyses were reasonably carried out. Also, for the verification of the advanced design concept, a large scale sodium thermal hydraulic test facility is being designed. Starting with the basic design of the test facility in 2008, its installation is scheduled to be completed by the end of 2011

  16. Uncertainties in fission-product decay-heat calculations

    Oyamatsu, K.; Ohta, H.; Miyazono, T.; Tasaka, K. [Nagoya Univ. (Japan)

    1997-03-01

    The present precision of the aggregate decay heat calculations is studied quantitatively for 50 fissioning systems. In this evaluation, nuclear data and their uncertainty data are taken from ENDF/B-VI nuclear data library and those which are not available in this library are supplemented by a theoretical consideration. An approximate method is proposed to simplify the evaluation of the uncertainties in the aggregate decay heat calculations so that we can point out easily nuclei which cause large uncertainties in the calculated decay heat values. In this paper, we attempt to clarify the justification of the approximation which was not very clear at the early stage of the study. We find that the aggregate decay heat uncertainties for minor actinides such as Am and Cm isotopes are 3-5 times as large as those for {sup 235}U and {sup 239}Pu. The recommended values by Atomic Energy Society of Japan (AESJ) were given for 3 major fissioning systems, {sup 235}U(t), {sup 239}Pu(t) and {sup 238}U(f). The present results are consistent with the AESJ values for these systems although the two evaluations used different nuclear data libraries and approximations. Therefore, the present results can also be considered to supplement the uncertainty values for the remaining 17 fissioning systems in JNDC2, which were not treated in the AESJ evaluation. Furthermore, we attempt to list nuclear data which cause large uncertainties in decay heat calculations for the future revision of decay and yield data libraries. (author)

  17. Decay Heat Removal for the Liquid Metal Fast Breeder Reactor

    The functional and reliability requirements of the decay heat removal systems are described. The reliability requirement and its rationale as adequate assurance that public health and safety are safeguarded are presented. The means by which the reliability of the decay heat removal systems are established to meet their requirement are identified. The heat removal systems and their operating characteristics are described. The discussion includes the overflow heat removal service and its role in decay heat removal if needed. The details of the systems are described to demonstrate the elements of redundancy and diversity in the systems design. The quantitative reliability assessment is presented, including the reliability model, the most important assumptions on which the analysis is based, sources of failure data, and the preliminary numerical results. Finally, the qualitative analyses and administrative controls will be discussed which ensure reliability attainment in design, fabrication, and operation, including minimization of common mode failures. A component test program is planned to provide reliability data on selected critical heat removal system equipment. This test plan is described including a definition of the test parameters of greatest interest and the motivation for the test article selection. A long range plan is also in place to collect plant operational data and the broad outlines of this plan are described. The paper closes with a statement of the high reliability of the Clinch River Breeder Reactor Plant decay heat removal systems and a summary of the supporting arguments. (author)

  18. Performance of ALMR passive decay heat removal system

    The Advanced Liquid Metal Reactor (ALMR) concept has a totally passive safety-grade decay heat removal system referred to as the Reactor Vessel Auxiliary Cooling System (RVACS) that rejects heat from the small (471 MWt) modular reactor to the environmental air by natural convection heat transfer. The system has no active components, requires no operator action to initiate, and is inherently reliable. The RVACS can perform its function under off-normal or degraded operating conditions without significant loss in performance. Several such events are described and the RVACS thermal performance for each is given and compared to the normal operation performance. The basic RVACS performance as well as the performance during several off-normal events have been updated to reflect design changes for recycled fuel with minor actinides for end of equilibrium cycle conditions. The performance results for several other off-normal events involving various degrees of RVACS air flow passage blockages are presented. The results demonstrated that the RVACS is unusually tolerant to a wide range of postulated faults. (author)

  19. Optimization design of emergency decay heat removal system for CEFR

    Background: China experimental fast reactor (CEFR) is the first fast reactor in China, the piping designs are very important for the fast reactor. Purpose: The purpose is to improve the economy of pipeline design for the fast reactor. Methods: According to the optimization principles, redesign the support system of emergency decay heat removal system. Results: The piping of emergency decay heat removal system meets the ASME standard stress limit value under various prospective loads, and reduces the number of dampers, spring hangers. Conclusions: We accumulate layout experience for the support design of high temperature piping by the optimization design for emergency decay heat removal system, lay the foundation for the fast reactor piping design in the future. (authors)

  20. Tests for removal of decay heat by natural convection

    Interim storage technology for spent fuel by dry storage casks have been investigated. The casks are vertically placed in a storage building. The decay heat is removed from the outer cask surface by natural convection of air entering from the building wall to the roof. The air flow pattern in the storage building was governed by the natural driving pressure difference and circulating flow. The purpose of this study is to understand the mechanism of the removal of decay heat from casks by natural convection. The simulated flow conditions in the building were assumed as a natural and forced combined convection and were investigated by the turbulent quantities near wall. (author)

  1. Easy-to-use application programs for decay heat and delayed neutron calculations on personal computers

    Oyamatsu, Kazuhiro [Nagoya Univ. (Japan)

    1998-03-01

    Application programs for personal computers are developed to calculate the decay heat power and delayed neutron activity from fission products. The main programs can be used in any computers from personal computers to main frames because their sources are written in Fortran. These programs have user friendly interfaces to be used easily not only for research activities but also for educational purposes. (author)

  2. Decay Heat Measurements Using Total Absorption Gamma-ray Spectroscopy

    Rice, S.; Valencia, E.; Algora, A.; Taín, J. L.; Regan, P. H.; Podolyák, Z.; Agramunt, J.; Gelletly, W.; Nichols, A. L.

    2012-09-01

    A knowledge of the decay heat emitted by thermal neutron-irradiated nuclear fuel is an important factor in ensuring safe reactor design and operation, spent fuel removal from the core, and subsequent storage prior to and after reprocessing, and waste disposal. Decay heat can be readily calculated from the nuclear decay properties of the fission products, actinides and their decay products as generated within the irradiated fuel. Much of the information comes from experiments performed with HPGe detectors, which often underestimate the beta feeding to states at high excitation energies. This inability to detect high-energy gamma emissions effectively results in the derivation of decay schemes that suffer from the pandemonium effect, although such a serious problem can be avoided through application of total absorption γ-ray spectroscopy (TAS). The beta decay of key radionuclei produced as a consequence of the neutron-induced fission of 235U and 239Pu are being re-assessed by means of this spectroscopic technique. A brief synopsis is given of the Valencia-Surrey (BaF2) TAS detector, and their method of operation, calibration and spectral analysis.

  3. Decay heat removal in HTGR by natural circulation

    The coolability of 1000MWt HTGR under complete loss of forced flow conditions was investigated. A dynamic simulator for nuclear power plants (DSNP) program was developed to study the evolution of natural circulation during loss of forced flow (LOF). It was concluded that a passive cooling device, having 0.3% heat removal capacity of nominal decay heat rate, is sufficient for emergency cooling of the proposed plant under total LOF. (author)

  4. Decay heat removal system in a medium size HTGR

    The present study investigates the operation of the decay heat removal system (DHR) during loss of flow (LOF) accident in which the primary flow is reduced to zero at full power operation of medium size high temperature gas reactor (HTGR). (author)

  5. Analysis of decay heat removal by natural convection in PFBR

    PFBR is a 500 MWe, 1200 MWt pool type LMFBR. In order to assure reliable decay heat removal, four totally independent Safety Grade Decay Heat Removal Systems (SGDHRS) which removes heat directly from the hot pool, is provided. Each of the SGDHRS comprises of a hot pool dipped decay heat exchanger (DHX), a sodium - air heat exchanger (AHX) at a suitable elevation and associated piping and circuits. This paper brings out the step by step approach that have been taken to decide on the preliminary sizing of the SGDHRS components, and static and transient analysis to assess the adequacy of the Decay Heat Removal capacity of the SGDHRS during the worst of the foreseen design basis conditions. The maximum values the important safety related temperatures viz., clad hotspot, hot pool top surface, reactor inlet, fuel subassembly outlets etc., would reach, can be obtained only through a comprehensive transient analysis. In order to get quick and reasonably meaningful results, one dimensional thermal-hydraulics models for the core, hot and cold pools, IHX, DHX, AHX and various pipings were developed and a code DHDYN formulated. With this a total power failure situation followed by initiations of DHR half an hour later was studied and the results revealed the following: (i) clad hotspot temperature in the in-vessel stored spent fuel subassemblies could be held below 800 deg. C only if primary sodium flow through these subassemblies are increased up to three times the originally allocated flow in the design, (ii) hotpool top zone temperature reaches 572 deg. C, (iii) reactor inlet temperature reaches 482 deg. C, (iv) the hot pool top zone temperature cools down to 450 deg. C in about 25 h. Thus these results satisfactorily established the adequacy of the sizing and the capability of the SGDHRS. DHDYN code is also used to study the RAMONA water experiments conducted in Germany. Initial results available has brought out the conservative nature of the DHDYN predictions as compared

  6. Decay heat calculations for a 500 kW W-Ta spallation target

    Yu, Quanzhi; Lu, Youlian; Hu, Zhiliang; Zhou, Bin; Yin, Wen; Liang, Tianjiao

    2015-05-01

    The China Spallation Neutron Source (CSNS) is a short-pulsed neutron scattering facility. The beam power is designed to be 100 kW in Phase I, with the capability of upgrading to 500 kW. Tantalum (Ta)-cladded tungsten (W) was chosen as the spallation target due to its high neutron yield. Ta claddings can solve the problem of the corrosiveness of W plates, although they produce high decay heat after intense irradiation. This paper presents the decay heat distributions and evolutions for the future upgraded 500 kW W-Ta spallation target. The calculations are performed using the MCNPX2.5 Monte Carlo code and the CINDER'90 activation code. The decay heat distributions show that for the W plates, decay heat is mainly produced via the spallation reaction process, whereas for the Ta claddings, it is mainly produced via the neutron capture process. An effective method of reducing the decay heat in the W-Ta target is also presented and discussed.

  7. Multidimensional Thermal-Hydraulic Analysis for Decay Heat Exchanger of PGSFR

    Hong, Jonggan; Yoon, Jung; Kim, Dehee; Lee, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The decay heat exchanger (DHX) of PGSFR is a shell-and-tube type counter-current flow sodium heat exchanger, and each unit is designed for the rated thermal power of 1.0 MWt, which is corresponding to the nominal design capacity of a single passive decay heat removal system (PDHRS) and active decay heat removal system (ADHRS) loops. The DHX unit is fully immersed in the cold sodium pool region and removes the system heat load sufficiently and reliably during the temperature transient. In this work, a multidimensional thermal-hydraulic analysis for the DHX was carried out numerically and the numerical results were compared with the calculated results of the 1-D DHX design code to verify the reliability of the design code. In addition, an influence of the cold pool sodium which flows into the shell-side of the DHX through the shell outlet was evaluated. The SHXSA code was conservative in calculating the pressure drop of the shell-side which is our major concern in designing the natural circulation of the decay heat removal system. It was revealed that the buffer region is needed to reduce the thermal stress in the lower tubesheet by the inflow of the cold pool sodium.

  8. Multidimensional Thermal-Hydraulic Analysis for Decay Heat Exchanger of PGSFR

    The decay heat exchanger (DHX) of PGSFR is a shell-and-tube type counter-current flow sodium heat exchanger, and each unit is designed for the rated thermal power of 1.0 MWt, which is corresponding to the nominal design capacity of a single passive decay heat removal system (PDHRS) and active decay heat removal system (ADHRS) loops. The DHX unit is fully immersed in the cold sodium pool region and removes the system heat load sufficiently and reliably during the temperature transient. In this work, a multidimensional thermal-hydraulic analysis for the DHX was carried out numerically and the numerical results were compared with the calculated results of the 1-D DHX design code to verify the reliability of the design code. In addition, an influence of the cold pool sodium which flows into the shell-side of the DHX through the shell outlet was evaluated. The SHXSA code was conservative in calculating the pressure drop of the shell-side which is our major concern in designing the natural circulation of the decay heat removal system. It was revealed that the buffer region is needed to reduce the thermal stress in the lower tubesheet by the inflow of the cold pool sodium

  9. Decaying particles do not heat up the universe

    It is usually assumed that a massive relic species, which comes to dominate the mass density of the Universe and later decays, heats up the Universe when the age of the Universe approx. = its lifetime. We show that if its decay follows the usual exponential decay law, then the Universe is never reheated, rather it tust cools more slowly. We calculate the evolution of the temperature and entropy, and find that to within numerical factors of order unity, the usual estimates for the entropy increase are found to be correct. Our results have implications for primordial nucleosynthesis in scenarios where a massive relic with lifetime approx. = 10-2 to 103 sec is present, and for baryogenesis in the new inflationary Universe scenario

  10. An analysis of decay heat power in the experimental VHTR

    Decay heat power of the typical fuels loaded in the experimental multipurpose very high temperature gas-cooled reactor (VHTR) has been calculated, based on the American National Standard which has been newly developped as to be applicable to light water reactors. Physical constants of the reactor core, such as fission power during operation, burn-up of fissile atoms and change in composition, have been evaluated with the VHTR lattice burn-up code DELIGHT-5. The analysis has been done for the fuels of different enrichments under a given power density and for the cases in which the power density changes during operation, then some characteristics of the VHTR decay heat, especially the effect of operation period, are shown. (author)

  11. Decay heat removal in GEN IV gas cooled fast reactors

    The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs) is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR) in a GEN IV direct-cycle gas-cooled fast reactor (GFR) which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  12. A revised ANS standard for decay heat from fission products

    The draft ANS 5.1 standard on decay heat was published in 1971 and given minor revision in 1973. Its basis was the best estimate working curve developed by K. Shure in 1961. Liberal uncertainties were assigned to the standard values because of lack of data for short cooling times and large discrepancies among experimental data. Research carried out over the past few years has greatly improved the knowledge of this phenomenon and a major revision of the standard has been completed. Very accurate determination of the decay heat is now possible, expecially within the first 104 seconds, where the influence of neutron capture in fission products may be treated as a small correction to the idealized zero capture case. The new standard accounts for differences among fuel nuclides. It covers cooling time to 109 seconds, but provides only an ''upper bound'' on the capture correction in the interval 104 9 seconds. (author)

  13. Current status of decay heat measurements, evaluations, and needs

    Over a decade ago serious concern over possible consequences of a loss-of-coolant accident in a commercial light-water reactor prompted support of several experiments designed specifically to measure the latent energy of beta-ray and gamma-ray emanations from fission products for thermal reactors. This latent energy was termed Decay Heat. At about the same time the American Nuclear Society convened a working group to develop a standard for use in computing decay heat in real reactor environs primarily for regulatory requirements. This working group combined the new experimental results and best evaluated data into a standard which was approved by the ANS and by the ANSI. The primary work since then has been: (a) on improvements to computational efforts and (b) experimental measurements for fast reactors. In addition, the need for decay-heat data has been extended well beyond the time regime of a loss-of-coolant accident; new concerns involve, for example, away-from-reactor shipments and storage. The efficacy of the ANS standard for these longer time regimes has been a subject of study with generally positive results. However, a specific problem, namely, the consequences of fission-product neutron capture, remains contentious. Satisfactory resolution of this problem merits a high priority. 31 refs., 4 figs., 1 tab

  14. HTGR spent fuel element decay heat and source term analysis

    Sund, R.E.; Strong, D.E.; Engholm, B.A.

    1977-02-01

    Decay heat, gamma dose rates, and neutron source strengths were determined for spent fuel elements from a High-Temperature Gas-Cooled Reactor (HTGR). The calculations were based on curie values reported in General Atomic Report GA-A13886 for the earlier commercial version of a 3000-MW(t) HTGR utilizing the thorium-uranium four-year fuel cycle. The reactor core was designed for an average thermal power density of 8.5 watts per cm/sup 3/ and a carbon-to-thorium atom ratio which varies between 210:1 and 240:1. Calculations of decay heat, gamma dose rates, and neutron source strengths were made for spent fuel elements from the initial core and from representative nonrecycle and recycle reloads. The study was performed for decay times from 180 days to 10 years. Tables of the isotopic results are given for both the fertile and fissile particles in the fuel elements. In addition, ordered tables of the important isotopic contributors are presented. Graphical presentations of the results are shown and discussed; in addition, comparisons are made with previous determinations.

  15. HTGR spent fuel element decay heat and source term analysis

    Decay heat, gamma dose rates, and neutron source strengths were determined for spent fuel elements from a High-Temperature Gas-Cooled Reactor (HTGR). The calculations were based on curie values reported in General Atomic Report GA-A13886 for the earlier commercial version of a 3000-MW(t) HTGR utilizing the thorium-uranium four-year fuel cycle. The reactor core was designed for an average thermal power density of 8.5 watts per cm3 and a carbon-to-thorium atom ratio which varies between 210:1 and 240:1. Calculations of decay heat, gamma dose rates, and neutron source strengths were made for spent fuel elements from the initial core and from representative nonrecycle and recycle reloads. The study was performed for decay times from 180 days to 10 years. Tables of the isotopic results are given for both the fertile and fissile particles in the fuel elements. In addition, ordered tables of the important isotopic contributors are presented. Graphical presentations of the results are shown and discussed; in addition, comparisons are made with previous determinations

  16. Castor-1C spent fuel storage cask decay heat, heat transfer, and shielding analyses

    This report documents the decay heat, heat transfer, and shielding analyses of the Gesellschaft fuer Nuklear Services (GNS) CASTOR-1C cask used in a spent fuel storage demonstration performed at Preussen Elektra's Wurgassen nuclear power plant. The demonstration was performed between March 1982 and January 1984, and resulted in cask and fuel temperature data and cask exterior surface gamma-ray and neutron radiation dose rate measurements. The purpose of the analyses reported here was to evaluate decay heat, heat transfer, and shielding computer codes. The analyses consisted of (1) performing pre-look predictions (predictions performed before the analysts were provided the test data), (2) comparing ORIGEN2 (decay heat), COBRA-SFS and HYDRA (heat transfer), and QAD and DOT (shielding) results to data, and (3) performing post-test analyses if appropriate. Even though two heat transfer codes were used to predict CASTOR-1C cask test data, no attempt was made to compare the two codes. The codes are being evaluated with other test data (single-assembly data and other cask data), and to compare the codes based on one set of data may be premature and lead to erroneous conclusions

  17. Effect of yeast antagonist in combination with heat treatment on postharvest blue mold decay and Rhizopus decay of peaches.

    Zhang, Hongyin; Wang, Lei; Zheng, Xiaodong; Dong, Ying

    2007-04-01

    The potential of using heat treatment alone or in combination with an antagonistic yeast for the control of blue mold decay and Rhizopus decay of peaches caused by Penicillium expansum and Rhizopus stolonifer respectively, and in reducing natural decay development of peach fruits, as well as its effects on postharvest quality of fruit was investigated. In vitro tests, spore germination of pathogens in PDB was greatly controlled by the heat treatment of 37 degrees C for 2 d. In vivo test to control blue mold decay of peaches, heat treatment and antagonist yeast, as stand-alone treatments, were capable of reducing the percentage of infected wounds from 92.5% to 52.5% and 62.5%, respectively, when peach fruits stored at 25 degrees C for 6 d. However, in fruit treated with combination of heat treatment and Cryptococcus laurentii, the percentage of infected wounds of blue mold decay was only 22.5%. The test of using heat treatment alone or in combination with C. laurentii to control Rhizopus decay of peaches gave a similar result. The application of heat treatment and C. laurentii resulted in low average natural decay incidences on peaches after storage at 4 degrees C for 30 days and 20 degrees C for 7 days ranging from 40% to 30%, compared with 20% in the control fruit. The combination of heat treatment and C. laurentii was the most effective treatment, and the percentage of decayed fruits was 20%. Heat treatment in combination with C. laurentii had no significant effect on firmness, TSS, ascorbic acid or titratable acidity compared to control fruit. Thus, the combination of heat treatment and C. laurentii could be an alternative to chemicals for the control of postharvest decay on peach fruits. PMID:17140691

  18. Fission yield covariance generation and uncertainty propagation through fission pulse decay heat calculation

    Highlights: • Fission yield data and uncertainty comparison between major nuclear data libraries. • Fission yield covariance generation through Bayesian technique. • Study of the effect of fission yield correlations on decay heat calculations. • Covariance information contribute to reduce fission pulse decay heat uncertainty. - Abstract: Fission product yields are fundamental parameters in burnup/activation calculations and the impact of their uncertainties was widely studied in the past. Evaluations of these uncertainties were released, still without covariance data. Therefore, the nuclear community expressed the need of full fission yield covariance matrices to be able to produce inventory calculation results that take into account the complete uncertainty data. State-of-the-art fission yield data and methodologies for fission yield covariance generation were researched in this work. Covariance matrices were generated and compared to the original data stored in the library. Then, we focused on the effect of fission yield covariance information on fission pulse decay heat results for thermal fission of 235U. Calculations were carried out using different libraries and codes (ACAB and ALEPH-2) after introducing the new covariance values. Results were compared with those obtained with the uncertainty data currently provided by the libraries. The uncertainty quantification was performed first with Monte Carlo sampling and then compared with linear perturbation. Indeed, correlations between fission yields strongly affect the uncertainty of decay heat. Eventually, a sensitivity analysis of fission product yields to fission pulse decay heat was performed in order to provide a full set of the most sensitive nuclides for such a calculation

  19. Beta decay of fission products for the non-proliferation and decay heat of nuclear reactors

    Today, nuclear energy represents a non-negligible part of the global energy market, most likely a rolling wheel to grow in the coming decades. Reactors of the future must face the criteria including additional economic but also safety, non-proliferation, optimized fuel management and responsible management of nuclear waste. In the framework of this thesis, studies on non-proliferation of nuclear weapons are discussed in the context of research and development of a new potential tool for monitoring nuclear reactors, the detection of reactor antineutrinos, because the properties of these particles may be of interest for the International Agency of Atomic Energy (IAEA), in charge of the verification of the compliance by States with their safeguards obligations as well as on matters relating to international peace and security. The IAEA encouraged its member states to carry on a feasibility study. A first study of non-proliferation is performed with a simulation, using a proliferating scenario with a CANDU reactor and the associated antineutrinos emission. We derive a prediction of the sensitivity of an antineutrino detector of modest size for the purpose of the diversion of a significant amount of plutonium. A second study was realized as part of the Nucifer project, an antineutrino detector placed nearby the OSIRIS research reactor. The Nucifer antineutrino detector is dedicated to non-proliferation with an optimized efficiency, designed to be a demonstrator for the IAEA. The simulation of the OSIRIS reactor is developed here for calculating the emission of antineutrinos which will be compared with the data measured by the detector and also for characterizing the level of background noises emitted by the reactor detected in Nucifer. In general, the reactor antineutrinos are emitted during radioactive decay of fission products. These radioactive decays are also the cause of the decay heat emitted after the shutdown of a nuclear reactor of which the estimation is an

  20. Development of a combined heat exchanger design concept for an SFR decay heat removal system

    A fast neutron spectrum reactor is one of the most promising options for efficient uranium resources utilization and a substantial reduction of radioactive waste to be disposed. To this end, the Korea Atomic Energy Research Institute (KAERI) has developed the own sodium cooled fast reactor(SFR) design concept since 1992, and recent efforts putting into this area have been focused on enhancement of plant safety complying with the lessons learned from the Fukushima nuclear power plant accident. In particular, a reliable decay heat removal (DHR) becomes one of the most important tasks in successful SFR design. Therefore, to achieve more reliable DHR performance, KAERI has developed the innovative design concept called the PDRC, which is similar to conventional DRACS but its detailed flow path inside the reactor vessel is very creative. The schematic of the heat transport system in DSFR 600 is depicted in Figure 1 as an example. In regard to the DHR operation, the internal flow path passing through the reactor core should be maintained at all time but, in accident conditions, converted from the normal heat transport mode using the intermediate heat transport system (IHTS) to the alternate path with the DRACS loops. If the normal heat transport path via the IHTS is not available, the DRACS shall substitute the normal path and remove total heat load including core decay and sensible heat from the primary sodium pool. Since heat rejection from the intermediate heat exchanger (IHX) is not guaranteed in this situation, the decay heat exchanger (DHX) becomes the only heat sink and thus its arrangement inside the reactor vessel plays an important role in determining DHR capability. In the current SFR design, however, the internal flow path from the hot pool to the cold pool is somewhat ambiguous due to the split flow ratio formed in a parallel path between IHXs and DHXs. This ambiguity results in a large uncertainty in DHX shell side flowrate and corresponding heat transfer

  1. Applications of the total absorption technique to improve reactor decay heat calculations: study of the beta decay of 102,104,105Tc

    The decay heat of the fission products plays an important role in predicting the heat-up of nuclear fuel after reactor shutdown. This form of energy release is calculated as the sum of the energy-weighted activities of all fission products P(t) = ΣEiλiNi(t), where Ei is the decay energy of nuclide i(gamma and beta component), λi is the decay constant of nuclide i and Ni(t) is the number of nuclide i at cooling time t. Even though the reproduction of the measured decay heat has improved in recent years, there is still a long standing discrepancy at t∼1000 s cooling time for some fuels. A possible explanation for this disagreement can been found in the work of Yoshida et al., who demonstrated that an incomplete knowledge of the β-decay of some Tc isotopes could be the source of the systematic discrepancy. We have recently measured the β-decay process of some Tc isotopes using a total absorption spectrometer at the IGISOL facility in Jyvaeskylae. The results of the measurements are discussed, along with their impact on summation calculations.

  2. Measurement and analysis of JOYO MK-II spent MOX fuel decay heat. 2

    Decay heat of the spent MOX fuel is important not only from the viewpoint of reactor safety concerning a decay heat removal at the reactor shut down, but also for the thermal design of the spent fuel storage and handling facility. In order to obtain the experimental data and to improve the accuracy of calculation, the decay heat of spent fuel subassemblies of the JOYO Mk-II core was measured. The burn-up was 66 GWd/t and the cooling time was between 40 and 150 days. Measured decay heat of the spent fuel subassemblies was approximately 1446 ± 24 - 663 ± 20 W. The decay heat was calculated by 'ORIGEN2' code and then it was compared with the measured value. In the 'ORIGEN2' calculation, the JENDL-3.2 cross section library and the JNDC-V2 decay data library were used and fuel power calculated by the core management code system 'MAGI' was used as a input. The ratios between calculated and experimental values, C/Es, were approximately between 0.94 and 0.90. The discrepancy between calculation and measurement was considered to be larger than the experimental error (1σ = 1.7 - 3.0%) or the uncertainty of calculated FP decay heat (1 - 2%). It appears due to the uncertainty of actinides decay heat and that indicates cross sections of actinides and initial composition of actinides are important to evaluate decay heat accurately. (author)

  3. Evaluation of Heat Removal Performance of Passive Decay Heat Removal system for S-CO2 Cooled Micro Modular Reactor

    The modular systems is able to be transported by large trailer. Moreover, dry cooling system is applied for waste heat removal. The characteristics of MMR takes wide range of construction area from coast to desert, isolated area and disaster area. In MMR, Passive decay heat removal system (PDHRS) is necessary for taking the advantage on selection of construction area where external support cannot be offered. The PDHRS guarantees to protect MMR without external support. In this research, PDHRS of MMR is introduced and decay heat removal performance is analyzed. The PDHRS guarantees integrity of reactor coolant system. The high level of decay heat (2 MW) can be removed by PDHRS without offsite power

  4. Measurement and analysis of JOYO MK-II spent MOX fuel decay heat (3)

    It is important to precisely evaluate decay heat of the spent MOX fuel not only from the viewpoint of reactor safety concerning a decay heat removal at the reactor shut down, but also for thermal design of the spent fuel storage and handling facility. In order to obtain the experimental data and to improve the accuracy of calculation, the decay heat of spent fuel subassemblies (Burn-up: 66 GWd/t) of the JOYO MK-II core was measured from the cooling time of 319 to 729 days. Measured decay heat of the spent fuel subassemblies was 351±16∼158±9W. The low flow rate measurement to make large temperature gradient between inlet and outlet of measurement system has allowed us to measure decay heat after cooling time of 500 days by less than 6% error (1σ). The decay heat was calculated by 'ORIGEN2' code using the JENDL-3.2 cross section library and the JNDC-V2 decay data and fission yield data library. Then it was compared with the measured value. The ratios between calculated and experimental value, C/Es, were approximately between 0.96 and 0.90. There exists a systematic discrepancy (6∼8%) between calculation and measurement, which was larger than the experimental error (1σ = 1.7∼6.0%). Decay heat was generated from actinides and fission products (FP). Major heat sources in actinides are 242Cm, 238Pu and 241Am. However, nuclides except for 242Cm were not considered as the cause of systematic discrepancy because these decay heat was almost constant throughout this measurement. After cooling time of 100 days, 95Zr, 95Nb, 106Rh and 144Pr remained as major FP decay heat source. As as result, the discrepancy appears due to the decay heat calculation uncertainty of 242Cm and these FP, or measurement error and further investigation will be required. (author)

  5. Transient Performance of Air-cooled Condensing Heat Exchanger in Long-term Passive Cooling System during Decay Heat Load

    In the event of a 'loss of coolant accident'(LOCA) and a non-LOCA, the secondary passive cooling system would be activated to cool the steam in a condensing heat exchanger that is immersed in an emergency cooldown tank (ECT). Currently, the capacities of these ECTs are designed to be sufficient to remove the sensible and residual heat from the reactor coolant system for 72 hours after the occurrence of an accident. After the operation of a conventional passive cooling system for an extended period, however, the water level falls as a result of the evaporation from the ECT, as steam is emitted from the open top of the tank. Therefore, the tank should be refilled regularly from an auxiliary water supply system when the system is used for more than 72 hours. Otherwise, the system would fail to dissipate heat from the condensing heat exchanger due to the loss of the cooling water. Ultimately, the functionality of the passive cooling system would be seriously compromised. As a passive means of overcoming the water depletion in the tank, Kim et al. applied for a Korean patent covering the concept of a long-term passive cooling system for an ECT even after 72 hours. This study presents transient performance of ECT with installing air-cooled condensing heat exchanger under decay heat load. The cooling capacity of an air-cooled condensing heat exchanger was evaluated to determine its practicality

  6. Decay heat measurement on fusion reactor materials and validation of calculation code system

    Maekawa, Fujio; Ikeda, Yujiro; Wada, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Decay heat rates for 32 fusion reactor relevant materials irradiated with 14-MeV neutrons were measured for the cooling time period between 1 minute and 400 days. With using the experimental data base, validity of decay heat calculation systems for fusion reactors were investigated. (author)

  7. Mixed-oxide fuel decay heat analysis for BWR LOCA safety evaluation

    The mixed-oxide (MOX) fuel decay heat behavior is analyzed for Boiling Water Reactor (BWR) Loss of Coolant Accident (LOCA) safety evaluation. The physical reasoning on why the decay heat power fractions of MOX fuel fission product (FP) are significantly lower than the corresponding decay heat power fractions of uranium-oxide (UOX) fuel FP is illustrated. This is primarily due to the following physical phenomena. -The recoverable energies per fission of plutonium (Pu)-239 and Pu-241 are significantly higher than those of uranium (U)-235 and U-238. Consequently, the fission rate required to produce the same amount of power in MOX fuel is significantly lower than that in UOX fuel, which leads to lower subsequent FP generation rate and associated decay heat power in MOX fuel than those in UOX fuel. - The effective FP decay energy per fission of Pu-239 is significantly lower than the corresponding effective FP decay energy per fission of U-235, e.g., Pu-239's 10.63 Mega-electron-Volt (MeV) vs. U-235's 12.81 MeV at the cooling time 0.2 second. This also leads to lower decay heat power in MOX fuel than that in UOX fuel. The FP decay heat is shown to account for more than 90% of the total decay heat immediately after shutdown. The FP decay heat results based on the American National Standard Institute (ANSI)/American Nuclear Society (ANS)-5.1-1979 standard method are shown very close to the corresponding FP decay heat results based on the ANSI/ANS-5.1-2005 standard method. The FP decay heat results based on the ANSI/ANS-5.1-1979 simplified method are shown very close to but mostly slightly lower than the corresponding FP decay heat results based on the ANSI/ANS-5.1-1971 method. The FP decay heat results based on the ANSI/ANS-5.1-1979 simplified method or the ANSI/ANS-5.1-1971 method are shown significantly larger than the corresponding FP decay heat results based on the ANSI/ANS-5.1-1979 standard method or the ANSI/ANS-5.1-2005 standard method. (authors)

  8. Validation of ORIGEN for LWR used fuel decay heat analysis with SCALE

    Highlights: • Evaluates SCALE capabilities of predicting decay heat in used nuclear fuel. • Validation basis includes 121 full-assembly decay heat measurements. • Key modeling assumptions and data are discussed. • Results indicate good agreement between calculated and measured decay heat. - Abstract: The energy release rate from the decay of radionuclides can be a critical design parameter for used nuclear fuel storage, transportation, and repository engineered systems. Validation of the SCALE nuclear analysis code system capabilities in predicting decay heat for commercial used fuel applications has been performed using decay heat measurements for fuel assemblies irradiated in pressurized and boiling water reactors. The experimental data used for validation include a large number of full-length-assembly decay heat measurements that were performed between 2003 and 2010 at the Swedish Central Interim Storage Facility for Spent Nuclear Fuel, Clab, operated by the Swedish Nuclear Fuel and Waste Management Company, SKB. The measured fuel assemblies cover the burnup range 14–51 GWd/MTU and cooling times between 12 and 27 years, which are times of interest to used fuel transportation and storage applications. The validation results indicate good agreement between calculated and measured decay heat values, generally within the reported measurement uncertainty. The effects of key modeling assumptions and data used in the calculations are presented and discussed

  9. Experimental investigation on melt coolability under bottom flooding with and without decay heat simulation

    Highlights: • The effect of decay heat on melt coolability under bottom flooding was studied. • Decay heat of 0.5 MW/m3 was simulated. • A single simulant material with same mass and initial temperature was used. • Quenching of melt pool does not depend on decay heat. • Comparison of with and without decay heat experiments has been presented. - Abstract: Investigations on severe accident phenomena help us in understanding the realistic accidental phenomena for the assessment of associated risk. The societal impact of radiological leakage to the environment has demanded further robustness in the line of defence of nuclear safety. Thus, to ensure the cooling and stabilization of corium within reactor containment in case of severe accident scenarios, many new reactors have been envisaged with core catcher. In this regard, corium coolability still remains an unresolved issue in spite of several efforts being taken towards its understanding. After studying the various cooling strategies, it has been demonstrated that melt coolability using bottom flooding of water is one of the most efficient techniques so far. To study the effect of decay heat on melt pool coolability under bottom flooding condition, two experiments have been performed in this paper; one without the decay heat and the other with decay heat. The test section used for carrying out these experiments consisted of two parts viz. lower part for retaining the melt from furnace, water inlet and melt quenching, and upper part for steam expansion and its outlet. The total height of the test section was 1400 mm and was made of 33 mm thick carbon steel. Total six stainless steel nozzles of diameter 12 mm were used for injecting water at the bottom of the melt pool. The lower part was surrounded by 10 radiative heaters to simulate decay heat of 10 kW which corresponds to 0.5 MW/m3. The experiments showed that quenching of about 25 l of melt at initial temperature of nearly 1200 °C took only a few minutes

  10. Probabilistic approach for decay heat uncertainty estimation using URANIE platform and MENDEL depletion code

    Tsilanizara, A.; Gilardi, N.; Huynh, T. D.; Jouanne, C.; Lahaye, S.; Martinez, J. M.; Diop, C. M.

    2014-06-01

    The knowledge of the decay heat quantity and the associated uncertainties are important issues for the safety of nuclear facilities. Many codes are available to estimate the decay heat. ORIGEN, FISPACT, DARWIN/PEPIN2 are part of them. MENDEL is a new depletion code developed at CEA, with new software architecture, devoted to the calculation of physical quantities related to fuel cycle studies, in particular decay heat. The purpose of this paper is to present a probabilistic approach to assess decay heat uncertainty due to the decay data uncertainties from nuclear data evaluation like JEFF-3.1.1 or ENDF/B-VII.1. This probabilistic approach is based both on MENDEL code and URANIE software which is a CEA uncertainty analysis platform. As preliminary applications, single thermal fission of uranium 235, plutonium 239 and PWR UOx spent fuel cell are investigated.

  11. Sodium Experiments on Natural Circulation Decay Heat Removal and 3D Simulation of Plenum Thermal Hydraulics

    Natural circulation decay heat removal is one of the significant issues for fast reactor safety, especially in long term station blackout events. Several sodium experiments were carried out using a 7-subassembly core model for core thermal hydraulics under natural circulation conditions and for onset transients of natural circulation in a decay heat removal system (DHRS) including natural draft. Significant heat removal via inter-wrapper flow was confirmed in the experiments. Solidification of sodium in an air cooler is one of key issues in loss of heat sink events. Natural circulation characteristics under long-term decay heat removal were also obtained. Multi-dimensional phenomena, e.g., thermal stratification and bypass flow in plenums and/or heat exchangers, may influence the natural circulation. Thus, 3D simulation method was developed for entire region in the primary loop. Comparison of temperature distributions in a DHRS heat exchanger between experiment and analysis was done. (author)

  12. Study of decay heat removal and structural assurance by LBB concept of tokamak components

    Since decay heat density in ITER is quite low, thermal analyses have shown that only natural dissipation due to thermal radiation can be sufficient for removal of decay heat even in loss of all coolant. Owing to this attractiveness, no cooling system would be required for decay heat removal. In addition, because a magnetically confined plasma terminates by a small amount of impurity ingress, there is no possibility of uncontrolled production of energy, which will damage the integrity of the vacuum vessel containing tritium and other radioactive materials. This statement can be assured with a high level of confidence resulted from the LBB (Leak Before Break) concept. (author)

  13. A study on the decay heat removal capability of a reactor vessel auxiliary cooling system

    A reactor vessel auxiliary cooling system (RVACS) is a potential candidate as a fully passive decay heat removal system for small FBRs. In this study the heat transfer performance of a collector with fins is discussed through experiment and the evaluation method is proposed for the heat removal capability of the system. (author)

  14. Time decay rates for the equations of the compressible heat-conductive flow through porous media

    Chen, Qing; Tan, Zhong; Wu, Guochun

    2015-11-01

    We consider the time decay rates of smooth solutions to the Cauchy problem for the equations of the compressible heat-conductive flow through porous media. We prove the global existence and uniqueness of the solutions by the standard energy method. Moreover, we establish the optimal decay rates of the solution as well as its higher-order spatial derivatives. And the damping effect on the time decay rates of the solution is studied in detail.

  15. Activation experiments on vanadium alloy NIFS-HEAT-2

    In the present study, activation analysis of impurities and evaluation of activation properties were performed on NIFS-HEAT-2 by DT neutron irradiation at FNS facility. Similar analysis and evaluation were performed on US and Chinese V-4Cr-Ti samples for comparison. For impurity analysis and direct evaluation of activation properties of vanadium alloys, activation experiments with DT neutron irradiations were performed on NIFS-HEAT-2 and Round-Robin samples from the US and China. Eight nuclides of 24Na, 28Al, 54Mn, 56Mn, 57Co, 58Co, 89Zr and 92mNb were identified form analysis of the gamma peaks and concentrations of Al, Si, Mn, Fe, Ni, Co, Zr, Nb and Mo were evaluated. It was confirmed that the concentration of Al in NIFS-HEAT-2, which is harmful for low activation property, was lower than the criteria required for recycling of used material after reactor shutdown. The results were almost consistent with those by chemical analysis. Until ∼8 months after irradiation, significant influence of impurities was not observed in the decay heat measurement. Results of decay heat measurement with the Whole Energy Absorption Spectrometer and those of calculation with MNCP-4C, ACT-4 and JENDL Activation File were consistent within ∼ 15%. Activation calculation considering impurity concentrations from the present analysis indicated that decay heat of 60Co transmuted from Ni impurity will be dominant ∼6 years after irradiation. (author)

  16. Application of the PSA method to decay heat removal systems in a large scale FBR design

    The Probabilistic Safety Assessment (PSA) method is applied to a large scale loop-type FBR in its conceptual design stage in order to establish a well-balanced safety. Both the reactor shut down and decay heat removal systems are designed to be highly reliable, e.g. 10-7/d. In this paper the results of several reliability analyses concerning the DHRS have been discussed, where the effects of the analytical assumptions, design options, accident managements on the reliability are examined. The reliability is evaluated small enough, since DRACSs consists of four independent loops with sufficient heat removal capacity and both forced and natural circulation capabilities are designed. It is found that the common mode failures for the active components in the DRACS dominate the reliability. The design diversity concerning these components can be effective for the improvements and the accident managements on BOP are also possible by making use of the long grace period in FBR. (author)

  17. Passive Decay Heat Removal Strategy of Integrated Passive Safety System (IPSS) for SBO-combined Accidents

    Kim, Sang Ho; Chang, Soon Heung; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-10-15

    The weak points of nuclear safety would be in outmoded nuclear power plants like the Fukushima reactors. One of the systems for the safety enhancement is integrated passive safety system (IPSS) proposed after the Fukushima accidents. It has the five functions for the prevention and mitigation of a severe accident. Passive decay heat removal (PDHR) strategy using IPSS is proposed for coping with SBO-combined accidents in this paper. The two systems for removing decay heat before core-melt were applied in the strategy. The accidents were simulated by MARS code. The reference reactor was OPR1000, specifically Ulchin-3 and 4. The accidents included loss-of-coolant accidents (LOCA) because the coolant losses could be occurred in the SBO condition. The examples were the stuck open of PSV, the abnormal open of SDV and the leakage of RCP seal water. Also, as LOCAs with the failure of active safety injection systems were considered, various LOCAs were simulated in SBO. Based on the thermal hydraulic analysis, the probabilistic safety analysis was carried out for the PDHR strategy to estimate the safety enhancement in terms of the variation of core damage frequency. AIMS-PSA developed by KAERI was used for calculating CDF of the plant. The IPSS was applied in the PDHR strategy which was developed in order to cope with the SBO-combined accidents. The estimation for initiating SGGI or PSIS was based on the pressure in RCS. The simulations for accidents showed that the decay heat could be removed for the safety duration time in SBO. The increase of safety duration time from the strategy provides the increase of time for the restoration of AC power.

  18. Filtered thermal neutron captured cross-sections measurements and decay heat calculations

    Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (Rcd) of 420 and neutron flux (Φth) of 1.6x106 n/cm2.s. This thermal neutron beam has been applied for measurements of capture cross-sections for nuclide of 51V, 55Mn, 180Hf and 186W by the activation method relative to the standard reaction 197Au(n,g)198Au. In addition to the activities of neutron capture cross-sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235U, 238U, 239Pu and 232Th are introduced in this report. (author)

  19. Fission Product Decay Heat Calculations for Neutron Fission of 232Th

    Son, P. N.; Hai, N. X.

    2016-06-01

    Precise information on the decay heat from fission products following times after a fission reaction is necessary for safety designs and operations of nuclear-power reactors, fuel storage, transport flasks, and for spent fuel management and processing. In this study, the timing distributions of fission products' concentrations and their integrated decay heat as function of time following a fast neutron fission reaction of 232Th were exactly calculated by the numerical method with using the DHP code.

  20. [The influence of oil heat treatment on wood decay resistance by Fourier infrared spectrum analysis].

    Wang, Ya-Mei; Ma, Shu-Ling; Feng, Li-Qun

    2014-03-01

    Wood preservative treatment can improve defects of plantation wood such as easy to corrupt and moth eaten. Among them heat-treatment is not only environmental and no pollution, also can improve the corrosion resistance and dimension stability of wood. In this test Poplar and Mongolian Seoteh Pine was treated by soybean oil as heat-conducting medium, and the heat treatment wood was studied for indoor decay resistance; wood chemical components before and after treatment, the effect of heat treatment on wood decay resistance performance and main mechanism of action were analysed by Fourier infrared spectrometric. Results showed that the mass loss rate of poplar fell from 19.37% to 5% and Mongolian Seoteh Pine's fell from 8.23% to 3.15%, so oil heat treatment can effectively improve the decay resistance. Infrared spectrum analysis shows that the heat treatment made wood's hydrophilic groups such as hydroxyl groups in largely reduced, absorbing capacity decreased and the moisture of wood rotting fungi necessary was reduced; during the heat treatment wood chemical components such as cellulose, hemicellu lose were degraded, and the nutrient source of wood rotting fungi growth necessary was reduced. Wood decay fungi can grow in the wood to discredit wood is because of that wood can provide better living conditions for wood decay fungi, such as nutrients, water, oxygen, and so on. The cellulose and hemicellulose in wood is the main nutrition source of wood decay fungi. So the oil heat-treatment can reduce the cellulose, hemicellulose nutrition source of wood decay fungi so as to improve the decay resistance of wood. PMID:25208386

  1. Development of whole energy absorption spectrometer for decay heat measurement on fusion reactor materials

    Maekawa, Fujio; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    To measure decay heat on fusion reactor materials irradiated by D-T neutrons, a Whole Energy Absorption Spectrometer (WEAS) consisting of a pair of large BGO (bismuth-germanate) scintillators was developed. Feasibility of decay heat measurement with WEAS for various materials and for a wide range of half-lives (seconds - years) was demonstrated by experiments at FNS. Features of WEAS, such as high sensitivity, radioactivity identification, and reasonably low experimental uncertainty of {approx} 10 %, were found. (author)

  2. Heat transfer in turbulent decaying swirl flow in a circular pipe

    Algifri, A. H.; Bhardwaj, R. K.; Rao, Y. V. N.

    1988-08-01

    Heat transfer coefficients for air are measured along a heated pipe for decaying swirl flow, generated by radial blade cascade. The results are compared with an expression proposed for predicting the heat transfer coefficients in swirling flow. The theoretical predictions are in good agreement with the experimental data, with average and maximum deviations of 7 and 11 percent, respectively. The application of the theoretical approach to the experimental results obtained by other investigators for heat transfer in a decaying swirl flow generated by short-twisted tapes and tangential slots at inlet also give rise to encouraging agreement.

  3. Beta and gamma decay-heat measurements for fast and thermal reactors, particularly for Pu-239

    Dickens, J.K.

    1981-01-01

    The mounting evidence suggests (a) that the ORNL thermal-neutron fission decay heat data are likely correct to within stated uncertainties; (b) present data files (ENDF/B-V and others related to it) require more effort, and as improvements are made agreement with ORNL results is likely to become better; and (c) fast fission decay heat, induced by reactor-spectrum neutrons, appears to be little, if any, different from thermal-neutron fission-decay heat. The ANS 5.1 working group seems to be moving toward the above position but the standard for /sup 235/U has not yet been revised. Using /sup 235/U decay-heat data for /sup 239/Pu is quite conservative. Use of /sup 235/U decay-heat data for /sup 241/Pu decay-heat data as required in the standard is conservative only because of the over-statement (by approx. = 8%) of the /sup 235/U data in the standard.

  4. Decay heat removal in pool type fast reactor using passive systems

    Highlights: ► Three dimensional thermal hydraulic analysis of decay heat system in a fast reactor model predictions compared with experimental results from PHENIX. ► Calculations confirm adequacy of natural convection in decay heat removal. ► Inter-wrapper flow found to reduce peak temperatures by 50 K in the blanket zone. - Abstract: Post shutdown decay heat removal in a fast reactor is one of the most important safety functions which must be accomplished with a very high reliability. To achieve high reliability, the fast breeder reactor design has emphasized on passive or near passive decay heat removal systems utilizing the natural convection in the heat removal path. A typical passive decay heat removal system used in recent designs of fast breeder reactors consists of a sodium to sodium heat exchanger and sodium to air heat exchanger which together remove heat directly from the hot pool to the final heat sink, which is air. Since these are safety systems, it is necessary to confirm the design with detailed numerical analysis. The numerical studies include pool hydraulics, natural convection phenomena in closed loops, flow through narrow gaps between SA, multi-scale modeling, etc. Toward understanding the evolution of thermal hydraulic parameters during natural convection decay heat removal, a three-dimensional CFD model for the primary system coupled with an appropriate one-dimensional model for the secondary system is proposed. The model has been validated against the results of natural convection test conducted in PHENIX reactor. Adopting the model for the Indian PFBR, six different decay heat removal cases have been studied which bring out the effect of safety grade decay heat removal system (SGDHRS) capacity, secondary sodium inventory and inter-wrapper flow heat transfer on the subassembly outlet temperatures that are important for safety evaluation of the reactor. From the results, it is concluded that the delay in initiation of SGDHRS, replacement

  5. Decay heat removal and heat transfer under normal and accident conditions in gas cooled reactors

    The meeting was convened by the International Atomic Energy Agency on the recommendation of the IAEA's International Working Group on Gas Cooled Reactors. It was attended by participants from China, France, Germany, Japan, Poland, the Russian Federation, Switzerland, the United Kingdom and the United States of America. The meeting was chaired by Prof. Dr. K. Kugeler and Prof. Dr. E. Hicken, Directors of the Institute for Safety Research Technology of the KFA Research Center, and covered the following: Design and licensing requirements for gas cooled reactors; concepts for decay heat removal in modern gas cooled reactors; analytical methods for predictions of thermal response, accuracy of predictions; experimental data for validation of predictive methods - operational experience from gas cooled reactors and experimental data from test facilities. Refs, figs and tabs

  6. Decay heat and anti-neutrino energy spectra in fission fragments from total absorption spectroscopy

    Rykaczewski, Krzysztof

    2015-10-01

    Decay studies of over forty 238U fission products have been studied using ORNL's Modular Total Absorption Spectrometer. The results are showing increased decay heat values, by 10% to 50%, and the energy spectra of anti-neutrinos shifted towards lower energies. The latter effect is resulting in a reduced number of anti-neutrinos interacting with matter, often by tens of percent per fission product. The results for several studied nuclei will be presented and their impact on decay heat pattern in power reactors and reactor anti-neutrino physics will be discussed.

  7. Total Absorption Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra and Decay Heat Calculations

    Porta A.

    2016-01-01

    Full Text Available Beta decay of fission products is at the origin of decay heat and antineutrino emission in nuclear reactors. Decay heat represents about 7% of the reactor power during operation and strongly impacts reactor safety. Reactor antineutrino detection is used in several fundamental neutrino physics experiments and it can also be used for reactor monitoring and non-proliferation purposes. 92,93Rb are two fission products of importance in reactor antineutrino spectra and decay heat, but their β-decay properties are not well known. New measurements of 92,93Rb β-decay properties have been performed at the IGISOL facility (Jyväskylä, Finland using Total Absorption Spectroscopy (TAS. TAS is complementary to techniques based on Germanium detectors. It implies the use of a calorimeter to measure the total gamma intensity de-exciting each level in the daughter nucleus providing a direct measurement of the beta feeding. In these proceedings we present preliminary results for 93Rb, our measured beta feedings for 92Rb and we show the impact of these results on reactor antineutrino spectra and decay heat calculations.

  8. Total Absorption Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra and Decay Heat Calculations

    Porta, A.; Zakari-Issoufou, A.-A.; Fallot, M.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Bui, V. M.; Cormon, S.; Estienne, M.; Agramunt, J.; Äystö, J.; Bowry, M.; Briz, J. A.; Caballero-Folch, R.; Cano-Ott, D.; Cucouanes, A.; Elomaa, V.-V.; Eronen, T.; Estévez, E.; Farrelly, G. F.; Garcia, A. R.; Gelletly, W.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Karvonen, P.; Kolhinen, V. S.; Kondev, F. G.; Martinez, T.; Mendoza, E.; Molina, F.; Moore, I.; Perez-Cerdán, A. B.; Podolyák, Zs.; Penttilä, H.; Regan, P. H.; Reponen, M.; Rissanen, J.; Rubio, B.; Shiba, T.; Sonzogni, A. A.; Weber, C.

    2016-03-01

    Beta decay of fission products is at the origin of decay heat and antineutrino emission in nuclear reactors. Decay heat represents about 7% of the reactor power during operation and strongly impacts reactor safety. Reactor antineutrino detection is used in several fundamental neutrino physics experiments and it can also be used for reactor monitoring and non-proliferation purposes. 92,93Rb are two fission products of importance in reactor antineutrino spectra and decay heat, but their β-decay properties are not well known. New measurements of 92,93Rb β-decay properties have been performed at the IGISOL facility (Jyväskylä, Finland) using Total Absorption Spectroscopy (TAS). TAS is complementary to techniques based on Germanium detectors. It implies the use of a calorimeter to measure the total gamma intensity de-exciting each level in the daughter nucleus providing a direct measurement of the beta feeding. In these proceedings we present preliminary results for 93Rb, our measured beta feedings for 92Rb and we show the impact of these results on reactor antineutrino spectra and decay heat calculations.

  9. Measurement and analysis of decay heat of fast reactor spent fuel

    Decay heat of the JOYO Mk-II spent fuel subassemblies was measured using the calorimetric method as a non-destructive examination. The measurement of the subassembly was taken in the spent fuel storage pond at JOYO. Its burn-up was approximately 60 GWd/t and the cooling time was between 24 and 258 days. The measured decay heat was compared with the calculated values by 'ORIGEN2' code using the cross section library of JENDL-3.2, and the decay data and the fission yield data library of JNDC-V2. Calculated to Experimental (C/E) values for the measured subassembly were 0.96 - 0.90. The decay heat generated by 238Pu and 241Am, which amount to 1% of initial composition of the fresh fuel, reached 6% - 17% of decay heat during 24 -258 days of cooling time. These results indicate that the initial composition and the burn-up calculation of actinides are important to accurately evaluate the decay heat of spent fuel. (author)

  10. A passive decay heat removal system for LWRs based on air cooling

    Highlights: • A passive decay heat removal system for LWRs is discussed. • An air cooler model which condenses steam is developed. • The decay heat can be removed by air coolers with forced convection. • The dimensions of the air cooler are proposed. - Abstract: The present paper describes the capability of an air cooling system (ACS) to remove decay heat from a core of LWR such as an advanced boiling water reactor (ABWR) and a pressurized water reactor (PWR). The motivation of the present research is the Fukushima severe accident (SA) on 11 March 2011. Since emergency cooling systems using electricity were not available due to station blackout (SBO) and malfunctions, many engineers might understand that water cooling was not completely reliable. Therefore, a passive decay heat removal (DHR) system would be proposed in order to prevent such an SA under the conditions of an SBO event. The plant behaviors during the SBO are calculated using the system code NETFLOW++ for the ABWR and PWR with the ACS. Two types of air coolers (ACs) are applied for the ABWR, i.e., a steam condensing air cooler (SCAC) of which intake for heat transfer tubes is provided in the steam region, and single-phase type of which intake is provided in the water region. The DHR characteristics are calculated under the conditions of the forced air circulation and also the natural air convection. As a result of the calculations, the decay heat can be removed safely by the reasonably sized ACS when heat transfer tubes are cooled with the forced air circulation. The heat removal rate per one finned heat transfer tube is evaluated as a function of air flow rate. The heat removal rate increases as a function of the air flow rate

  11. A passive decay heat removal system for LWRs based on air cooling

    Mochizuki, Hiroyasu, E-mail: mochizki@u-fukui.ac.jp [Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan); Yano, Takahiro [Graduate School of Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan)

    2015-05-15

    Highlights: • A passive decay heat removal system for LWRs is discussed. • An air cooler model which condenses steam is developed. • The decay heat can be removed by air coolers with forced convection. • The dimensions of the air cooler are proposed. - Abstract: The present paper describes the capability of an air cooling system (ACS) to remove decay heat from a core of LWR such as an advanced boiling water reactor (ABWR) and a pressurized water reactor (PWR). The motivation of the present research is the Fukushima severe accident (SA) on 11 March 2011. Since emergency cooling systems using electricity were not available due to station blackout (SBO) and malfunctions, many engineers might understand that water cooling was not completely reliable. Therefore, a passive decay heat removal (DHR) system would be proposed in order to prevent such an SA under the conditions of an SBO event. The plant behaviors during the SBO are calculated using the system code NETFLOW++ for the ABWR and PWR with the ACS. Two types of air coolers (ACs) are applied for the ABWR, i.e., a steam condensing air cooler (SCAC) of which intake for heat transfer tubes is provided in the steam region, and single-phase type of which intake is provided in the water region. The DHR characteristics are calculated under the conditions of the forced air circulation and also the natural air convection. As a result of the calculations, the decay heat can be removed safely by the reasonably sized ACS when heat transfer tubes are cooled with the forced air circulation. The heat removal rate per one finned heat transfer tube is evaluated as a function of air flow rate. The heat removal rate increases as a function of the air flow rate.

  12. Los Alamos PWR decay-heat-removal studies. Summary results and conclusions

    Boyack, B E; Henninger, R J; Horley, E; Lime, J F; Nassersharif, B; Smith, R

    1986-03-01

    The adequacy of shutdown-decay-heat removal in pressurized water reactors (PWRs) is currently under investigation by the Nuclear Regulatory Commission. One part of this effort is the review of feed-and-bleed procedures that could be used if the normal cooling mode through the steam generators were unavailable. Feed-and-bleed cooling is effected by manually activating the high-pressure injection (HPI) system and opening the power-operated relief valves (PORVs) to release the core decay energy. The feasibility of the feed-and-bleed concept as a diverse mode of heat removal has been evaluated at the Los Alamos National Laboratory. The TRAC-PF1 code has been used to predict the expected performance of the Oconee-1 and Calvert Cliffs-1 reactors of Bobcock and Wilcox and Combustion Engineering, respectively, and the Zion-1 and H.B. Robinson-2 plants of Westinghouse. Feed and bleed was successfully applied in each of the four plants studied, provided it was initiated no later than the time of loss of secondary heat sink. Feed and bleed was successfully applied in two of the plants, Oconee-1 and Zion-1, provided it was initiated no later than the time of primary system saturation. Feed and bleed in Calvert Cliffs-1 when initiated at the time of primary system saturation did result in core dryout; however, the core heatup was eventually terminated by coolant injection. Feed-and-bleed initiation at primary system saturation was not studied for H.B. Robinson-2. Insights developed during the analyses of specific plant transients have been identified and documented. 33 refs., 107 figs., 26 tabs.

  13. Los Alamos PWR decay-heat-removal studies. Summary results and conclusions

    The adequacy of shutdown-decay-heat removal in pressurized water reactors (PWRs) is currently under investigation by the Nuclear Regulatory Commission. One part of this effort is the review of feed-and-bleed procedures that could be used if the normal cooling mode through the steam generators were unavailable. Feed-and-bleed cooling is effected by manually activating the high-pressure injection (HPI) system and opening the power-operated relief valves (PORVs) to release the core decay energy. The feasibility of the feed-and-bleed concept as a diverse mode of heat removal has been evaluated at the Los Alamos National Laboratory. The TRAC-PF1 code has been used to predict the expected performance of the Oconee-1 and Calvert Cliffs-1 reactors of Bobcock and Wilcox and Combustion Engineering, respectively, and the Zion-1 and H.B. Robinson-2 plants of Westinghouse. Feed and bleed was successfully applied in each of the four plants studied, provided it was initiated no later than the time of loss of secondary heat sink. Feed and bleed was successfully applied in two of the plants, Oconee-1 and Zion-1, provided it was initiated no later than the time of primary system saturation. Feed and bleed in Calvert Cliffs-1 when initiated at the time of primary system saturation did result in core dryout; however, the core heatup was eventually terminated by coolant injection. Feed-and-bleed initiation at primary system saturation was not studied for H.B. Robinson-2. Insights developed during the analyses of specific plant transients have been identified and documented. 33 refs., 107 figs., 26 tabs

  14. Decay heat analysis of a VHTR core using the HELIOS and origen-2 codes

    This paper describes the procedure and results of a decay heat analysis in a relatively short time after a shutdown for the safety analysis of a VHTR core. In this analysis, HELIOS provides the one-group actinide cross sections to ORIGEN-2 through the 190 group lattice calculation for a single fuel block. Then, ORIGEN-2 performs the depletion and decay heat calculations using these actinide cross sections. After benchmarking this procedure against a PWR core, it was applied to a 200 MWth prismatic VHTR core. The results showed that the decay heat per unit operating power is very comparable to that for a typical large power PWR core, although the decay heat per unit heavy metal mass is three times higher than that in the PWR core. It was also found from the results that the decay heat fraction to operating power decreases very slowly with the core burnup after it reaches a maximum value of 6.1 percents at 5 GWd/tHM. (authors)

  15. Revisions to the decay heat standard: ANSI/ANS 5.1

    Brady Raap, M. C. [Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA 99352 (United States); Gauld, I. C. [Oak Ridge National Laboratory, Oak Ridge, TN 37832 (United States); Dickens, J. K. [Dept. of Physics, Univ. of Tennessee, Knoxville, TN 37996 (United States); Wilson, W. B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2006-07-01

    This paper presents a summary of the 2005 revision to ANSI/ANS-5.1, Decay Heat Power for Light Water Reactors. The 2005 revision to ANSI/ANS-5.1 [1] represented an important milestone for this Standard. The reconstitution of the working group, incorporation of ENDF/B-VI data, and revisions to the 'simplified method' are the most significant accomplishments realized in the approval and publication of this Standard. A discussion comparing the content of the 2005 revision to the previous version of the Standard [2] is provided. In addition, an outline of the current activities of the working group and goals for the next revision is presented. (authors)

  16. The decay heat of fission products and actinides of the SNR-300

    The report describes the computer code RASPA, which calculates the build-up and decay of fission products and actinides. The verification of the code and its library has been performed by comparison with theoretical and experimental results of other authors, whereby a good agreement has been achieved. Furthermore, an error analysis has shown, that the error of the calculated decay heat, which is induced by uncertainties of nuclear data, is less than 10 % up to decay times of one month. The results of calculations of the time dependent decay heat and the gamma source strength in various zones of the cores Mark-Ia and Mark-II of the SNR-300 are documented and discussed in detail

  17. Validation of ORIGEN-S decay heat predictions for LOCA analysis

    Recent developments in the nuclear data libraries used by the ORIGEN-S isotope generation and depletion code have enabled the extension of the code to accurately predict the delayed energy release rates from nuclear decay (decay heat) at very short cooling times of interest to reactor accident analysis. Historically this time domain has required integral methods, such as the ANS-5.1 decay heat standard, because isotopic summation codes could not be reliably applied due to incomplete nuclear data. This paper describes work to validate ORIGEN-S against experimental measurements for decay times that extend down to about 1 second after fission. Benchmarks using measured gamma ray spectra following fission are also included because these results are important to predicting spatial energy deposition from delayed gamma energy release. (authors)

  18. Investigation of interaction between heat transport systems during the natural circulation decay heat removal in FBRs. Influence of decay heat removal system type and the secondary heat transport system

    Steady state sodium experiments were performed to investigate interactions between the heat transport systems, i.e., the primary system, the secondary system, and the decay heat removal system, during the natural circulation decay heat removal in FBRs. The test rig was used for the experiments. The core model has seven subassemblies; the center assembly simulates pin bundle geometry of a core fuel subassembly in a large scale FBR and consists of 37 pins, six outer subassemblies consists of 7 pins. As the decay heat removal system, Direct Reactor Auxiliary Cooling System (DRACS) and Primary Reactor Auxiliary Cooling System (PRACS) can be selected. Experiments were carried out under natural circulation conditions in the primary loop and force convection conditions in the decay heat removal system. In cases using DRACS, natural circulation flow rate in the primary loop was smaller by 20% than that in cases using PRACS due to the low temperature in the upper plenum and also in the upper non-heated section of the core. When natural circulation was allowed in the secondary heat transport system, the natural circulation flow rate in the primary system increased in spite of the operation of DRACS. In cases using DRACS, inter-subassembly flow redistribution occurred; the center subassembly had larger flow rate than those in outer subassemblies due to the low natural circulation head in the outer subassemblies which were cooled by the inter-wrapper flow (IWF). The highest temperature in the core was reduced by IWF via not only the direct cooling effect but also the inter-subassembly flow redistribution. (J.P.N.)

  19. Preliminary Test of a small heat pipe for hybrid control rod in-core passive decay heat removal system

    This paper introduces 'Hybrid control rod' combining its original function and heat removal ability. The high temperature operation and high resistance of radiation should be considered to adopt the hybrid heat pipe at the in-core condition. Other design consideration is to make extra inlet parts because it has a high risk of inlet boundary failure. It means that the introduction of heat pipe system is difficult to present nuclear power plants. The other concepts are presented to out-core cooling design but it has low performance compared with in-core heat removal system. Hybrid heat pipe for in-core heat removal system suggests the solution of these problems. Ultimate objective of this research is to develop the passive emergency decay heat removal system using hybrid heat pipes targeting design bases accidents such as station black-out (SBO) and small break loss of coolant accident (SBLOCA). The purpose of this work is to confirm the performance and heat transfer behavior of hybrid heat pipe. The hybrid heat pipe has special condition for operation. Therefore, it is hard to analyze their behavior in core. Table I shows the characteristics of hybrid heat pipe and consideration for manufacturing the heat pipe

  20. Preliminary Test of a small heat pipe for hybrid control rod in-core passive decay heat removal system

    Kim, In Guk; Ban, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-05-15

    This paper introduces 'Hybrid control rod' combining its original function and heat removal ability. The high temperature operation and high resistance of radiation should be considered to adopt the hybrid heat pipe at the in-core condition. Other design consideration is to make extra inlet parts because it has a high risk of inlet boundary failure. It means that the introduction of heat pipe system is difficult to present nuclear power plants. The other concepts are presented to out-core cooling design but it has low performance compared with in-core heat removal system. Hybrid heat pipe for in-core heat removal system suggests the solution of these problems. Ultimate objective of this research is to develop the passive emergency decay heat removal system using hybrid heat pipes targeting design bases accidents such as station black-out (SBO) and small break loss of coolant accident (SBLOCA). The purpose of this work is to confirm the performance and heat transfer behavior of hybrid heat pipe. The hybrid heat pipe has special condition for operation. Therefore, it is hard to analyze their behavior in core. Table I shows the characteristics of hybrid heat pipe and consideration for manufacturing the heat pipe.

  1. A simple method for evaluation of uncertainties in fission product decay heat summation calculations

    The present precision of nuclear data for the aggregate decay heat evaluation is analyzed quantitatively for 50 fissioning systems. In the practical calculation, a simple approximate method is proposed in order to avoid complication of the calculation and to point out easily the main causal nuclei of the uncertainties in decay heat calculations. As for the independent yield, the correlation among the values is taken into account. For this evaluation, nuclear data and their uncertainty data are taken from ENDF/B-VI nuclear data library. (author)

  2. Water test of natural circulation for decay heat removal in JSFR

    Japan Atomic Energy Agency (JAEA) is conducting a design study of Japan Sodium-cooled Fast Reactor (JSFR), in which a decay heat removal system (DHRS) utilizing natural circulation (NC) is applied as an innovative technology. The Central Research Institute of Electric Power Industry (CRIEPI) has carried out a water test to verify the applicability of NC to decay heat removal. The test used a 1/10-scale model of JSFR. Key issues on thermal-hydraulics were identified through simulation tests on representative events. Measures were also proposed to resolve these issues. The present study has demonstrated that a sufficient and stable NC is established in each event. (author)

  3. A probabalistic reliability evaluation of decay heat removal system using phased mission method and Markov model

    This paper presents a reliability evaluation model based on the 'phased mission method' combined with the Markov model and the results of its application to the decay heat removal system (DHRS) of a large tank-type FBR. The new approach divides the mission time into several time phases and the unreliability value in each time phase is calculated by solving simultaneous differential equations based on the Markov model. An application to an FBR decay heat removal system evaluation has shown that this realistic approach offers a methodology for improving reliability values by a factor of 10 as compared with the conventional fault tree method. (author)

  4. Overview report of RAMONA-NEPTUN program on passive decay heat removal

    The design of the advanced sodium-cooled European Fast Reactor provides a safety graded decay heat removal concept which ensures the coolability of the primary system by natural convection when forced cooling is lost. The findings of the RAMONA and NEPTUN experiments indicate that the decay heat can be safely removed by natural convection. The operation of the decay heat exchangers being installed in the upper plenum causes the formation of a thermal stratification associated with a pronounced temperature gradient. The vertical extent of the stratification and the qualitity of the gradient are depending on the fact whether a permeable or an impermeable shell covers the above core structure. A delayed startup time of the decay heat exchangers leads only to a slight increase of the temperatures in the upper plenum. A complete failure of half of the decay heat exchangers causes a higher temperature level in the primary system, but does not alter the global temperature distribution. The transient development of the temperatures is faster going on in a three-loop model than in a four-loop model due to the lower amount of heat stored in the compacter primary vessel. If no coolant reaches the core inlet side via the intermediate heat exchangers, the core remains coolable. In this case, cold water of the upper plenum penetrates into the subassemblies (thermosyphon effects) and the interwrapper spaces existing in the NEPTUN core. The core coolability from above is feasible without any difficulty though the temperatures increase to a minor degree at the top end of the core. The thermal hydraulic computer code FLUTAN was applied for the 3D numerical simulation of the majority of the steady state RAMONA and NEPTUN tests as well as for selected transient RAMONA tests. (orig./HP)

  5. Distribution of the decay heat in various modul HTRs and influence on peak fuel temperatures

    A unique feature of modular high-temperature reactors (MODUL-HTRs) is their benign response to a Loss-Of-Coolant Accident (LOCA). The reactor inherently becomes subcritical; the decay power partly heats up the reactor and partly is removed to the environment via thermal conduction and radiation, while avoiding overheating of the fuel. Production, storage, and removal of the decay heat is studied for different MODUL-HTR concepts having annular-core designs and thermal-powers of 350 MWt. Based on use of Low-Enriched-Uranium/Thorium (LEU/Th) fuel cycles in Prismatic-Fueled Reactors (PFRs), and LEU fuel cycles in Pebble-Bed-Reactors (PBRs), the following has been determined: (1) Comparison of a PFR and a PBR having essentially the same design shows higher decay heat production in the PFR due to a higher fission-product inventory and to the decay of 233Pa bred from 232Th; comparison also shows lower heat-transport rates from the pebble-bed core during a LOCA due to the lower thermal conductivity of the core. (2) Changing the PBR design to utilize carbon bricks and an additional coolant gap in the outer regions of the reactor adds significant barriers to the transport of decay heat to the Reactor Cavity Cooling System (RCCS) which is external to the reactor vessel. (3) In HTRs for Gas-Turbine (GT) applications, the operating temperature of the reactor is higher than in Steam turbine Cycle (SC) HTRs; consequently, under LOCAs the relative heat transport to the RCCS is higher in GT-HTRs. As a result, during a LOCA the amount of heat energy stored in the GT-HTR cores was only about 50% of the amount stored in SC-HTR cores. (author). 8 refs, 9 figs, 5 tabs

  6. The effect of the decay data on activation cross section

    The effect of the decay data on evaluation of activation cross section is investigated. Present work shows that these effects must be considered carefully when activation cross section is evaluated. Sometime they are main reason for causing the discrepancies among the experimental data

  7. Conceptual study of ferromagnetic pebbles for heat exhaust in fusion reactors with short power decay length

    Gierse, N.; Coenen, J W; C. Thomser; Panin, A.; Ch. Linsmeier; Unterberg, B.; Philipps, V

    2015-01-01

    Ferromagnetic pebbles are investigated as high heat flux (q∥) plasma facing components in fusion devices with short power decay length (λq) on a conceptual level. The ability of a pebble concept to cope with high heat fluxes is retained and extended by the acceleration of ferromagnetic pebbles in magnetic fields. An alloying concept suited for fusion application is outlined and the compatibility of ferromagnetic pebbles with plasma operation is discussed. Steel grade 1.4510 is chosen as a ...

  8. Thyroid activity in heat adaptation

    The effect of acute and chronic (22 day round-the-clock) exposure to microenvironmental heat stress (37 deg C DBT) on thyroid activity was studied in Hariana x Holstein Frisian, Hariana x Brown Swiss and Hariana x Jersey non-cycling F1 crossbred heifers. Vis-a-vis their no-heat norms, the percentage uptake of tri-iodothyronine-125I by resin registered a steep fall (about 45 to 60 percent) on acute heat exposures reaching a minimum value in about 2 hrs. The levels started recouping by the 2nd day, plateuing out on the 5th day onwards at slightly subnormal level with up and down fluctuations throughout the three week duration of exposure to heat. There were no significant differences in the pattern or magnitude of response amongst breeds, though in case of Holstein Frisian and Brown Swiss cross-breds the levels of T3 tended, at times, to overshoot the no-stress norm. (author)

  9. DECAY RESISTANCE AND PHYSICAL PROPERTIES OF OIL HEAT TREATED ASPEN WOOD

    Behzad Bazyar

    2011-12-01

    Full Text Available The decay resistance of oil-heat treated aspen wood (Populus tremula l. against white rot fungi (Coriolus versicolor and brown rot fungi (Coniophora puteana was investigated. Three different temperature stages and two time levels for oil heat treatment for the selection of optimum conditions were determined. Linseed oil as a heating medium was used. The mass loss of treated samples that were exposed to both fungi was significantly lower than that of the control samples. Results also showed improvement in dimensional stability after oil heat treatment. Decay resistance and dimensional stability of aspen wood were increased significantly with temperature increasing, but time seemed to have no effect on those properties. Oil heat treatment is a suitable method to improve decay resistance of aspen wood as it reduced the mass loss by 71% and 77% against Coriolus versicolor and Coniophora puteana compared with control samples, respectively. On the other hand, oil heat treatment improved the dimensional stability by about 20.5%.

  10. Feasibility study on enhancement of decay heat removal capacity in LMR using radiation structures

    In this study, a quantitative analysis of heat transfer enhancement by using the radiation structure installed in hot air riser of PSDRS in KALIMER is performed and a feasibility of designing a large thermal rating power plant is investigated in view of decay heat removal capacity. The heat transfer enhancement by radiation structure is directly proportional to the increasing the number of radiation structure, gap width of air flow path, and the temperature of heat transfer area contacting to the natural circulating air. Based on these analyses results of the enhancement of decay heat removal capacity, the feasible maximum core power of a large thermal rating power plant is investigated, and it is founded that the higher operation temperature of reactor coolant system, the larger thermal rating power plant design is possible and the enhancement is about 30% ∼ 40%, quantitatively. From the analyses results, it is expected that a large thermal rating power plant of about 1,000MWt is feasible to design in view of the enhancement of decay heat removal capability

  11. Short term fission product and actinide decay heat for a PWR

    This note gives the results of best estimate calculations of the decay heat following reactor trip for the UK PWR using UK recommended methods. It is intended that these values, together with the uncertainties identified, should be used for the analysis of reactor transients following shutdown. This requires the use of the computer code FISPIN (or a similar code FISP) together with the First UK Library of Fission Product Decay Data (UKPFDD-1), the Crouch 2 fission yields and group averaged fission product capture cross sections recommended individually for each reactor type. The calculations reported here conform to this standard. Decay heat from heavy elements (identified as actinides in this report) is also calculated in FISPIN. (U.K.)

  12. VVER-1000/V320 decay heat analysis involving TVS-M and TVSA fuel assemblies

    Petkov, Plamen V. [' Kozloduy' NPP, 3321 Kozloduy, Vratsa (Bulgaria)], E-mail: pvpetkov@yahoo.com; Hristov, Danail V. [' Kozloduy' NPP, 3321 Kozloduy, Vratsa (Bulgaria)], E-mail: dvhristov@npp.bg

    2008-12-15

    MELCOR 1.8.4 is an integral computer code, developed for severe accident calculations. It is used primarily for the simulation of PWR and BWR types of reactors as there exists an internal database, suitable for modeling of their core inventory. Despite similarity between VVER-1000/V320 and PWR, accounting of specificities of Russian reactor designs is still required. Part of it is the simulation of core decay heat rate after the shutdown. MELCOR 1.8.4 distinguishes fifteen classes. Each of them contains chemical elements with similar properties. Twelve are involved in radioactive products decay. In current paper the authors present two boundary reactor core loadings, designed with corresponding fuel assemblies: TVS-M and TVSA. They have calculated decay heat after reactor shutdown from 100% and 104% of nominal power by SCALE 4.4a package. The amount of generated nuclides had also been estimated. Irradiation history had been accounted as proposed in Kolobashkin et al. (p. 141) [Kolobashkin, V.M., Rubtsov, P.M., Rujanskiy, P.A., Sidorenko, V.D., 1983. Radionuclide Inventory Estimation Handbook (on Russian). Energoatomizdat, Moscow, pp. 138-188]. Newly developed Core Inventory Estimation Tool (CIET), described in this paper, written and tested previously, has been used for the evaluation of core decay heat fractions, distributed over chemical classes. Twelve curves were generated by following the same numerical procedure implemented in MELCOR for representation of decay in W/kg. Comparison of chemical element decay rates to the defaults for PWR shows deviations from the expectations to maximal values of 37% in Uranium for TVSA fuel assemblies. The total number of radionuclides, separated in chemical classes, given in Gauntt et al. [Gauntt, R.O., Cole, R.K., Rodrigez, S.B., Sanders, R.L., Smith, R.C., Stuard, D.S., Summers, R.M., Young, M.F., 1997. MELCOR Computer Code Manuals. NUREG/CR-6119 Report, Vol. 1 and Vol. 2, SAND97-2398] was compared to the ones involved in

  13. Integral decay-heat measurements and comparisons to ENDF/B--IV and V

    England, T.R.; Schenter, R.E.; Schmittroth, F.

    1978-05-22

    Results from recent integral decay-power experiments are presented and compared with summation calculations. The experiments include the decay power following thermal fission of /sup 233/U, /sup 235/U, and /sup 239/Pu. The summation calculations use ENDF/B-IV decay data and yields from Versions IV and V. Limited comparisons of experimental ..beta.. and ..gamma.. spectra with summation calculations using ENDF/B-IV are included. Generalized least-squares methods are applied to the recent /sup 235/U and /sup 239/Pu decay-power experiments and summation calculations to arrive at evaluated values and uncertainties. Results for /sup 235/U imply uncertainties less than 2% (1 sigma) for the ''infinite'' exposure case for all cooling times greater than 10 seconds. The uncertainties for /sup 239/Pu are larger. Accurate analytical representations of the decay power are presented for /sup 235/,/sup 238/U, and /sup 239/Pu for use in light-water reactors and as the nominal values in the new ANS 5.1 Draft Standard (1978). Comparisons of the nominal values with ENDF/B-IV and the 1973 ANS Draft Standard in current use are included. Gas content, important to decay-heat experiments, and absorption effects on decay power are reviewed. 37 figures, 8 tables.

  14. Integral decay-heat measurements and comparisons to ENDF/B-IV and V

    England, T.R.; Schenter, R.E.; Schmittroth, F.

    1978-07-01

    Results from recent integral decay-power experiments are presented and compared with summation calculations. The experiments include the decay power following thermal fission of /sup 233/U, /sup 235/U, and /sup 239/Pu. The summation calculations use ENDF/B-IV decay data and yields from Versions IV and V. Limited comparisons of experimental ..beta.. and ..gamma.. spectra with summation calculations using ENDF/B-IV are included. Generalized least-squares methods are applied to the recent /sup 235/U and /sup 239/Pu decay-power experiments and summation calculations to arrive at evaluated values and uncertainties. Results for /sup 235/U imply uncertainties less than 2% (1 sigma) for the ''infinite'' exposure case for all cooling times greater than 10 seconds. The uncertainties for /sup 239/Pu are larger. Accurate analytical representations of the decay power are presented for /sup 235/ /sup 238/U, and /sup 239/Pu for use in light-water reactors and as the nominal values in the new ANS 5.1 Draft Standard (1978). Comparisons of the nominal values with ENDF/B-IV and the 1973 ANS Draft Standard in current use are included. Gas content, important to decay-heat experiments, and absorption effects on decay power are reviewed. 37 figures, 8 tables.

  15. Application of optimal estimation techniques to FFTF decay heat removal analysis

    The verification and adjustment of plant models for decay heat removal analysis using a mix of engineering judgment and formal techniques from control theory are discussed. The formal techniques facilitate dealing with typical test data which are noisy, redundant and do not measure all of the plant model state variables directly. Two pretest examples are presented. 5 refs

  16. Markov analysis for time dependent success criteria of passive decay heat removal system

    Highlights: • Unavailability estimation of decay heat removal system with time dependent success criteria. • Dynamic modeling of the system under both continuous and periodic monitoring schemes. • Sensitivity of unavailability to various factors. • Comprehensive Markov modeling with and without considering common cause failures. • Estimation of upper bound and lower bound for the mean unavailability of decay heat removal system. - Abstract: Safety systems deployed in nuclear industry are generally required to operate for a particular mission time. Most of such systems employ redundancy to ensure their high availability over the stipulated mission time. However, availability of a system with redundant configuration depends upon success criteria and is application-specific. The Safety Grade Decay Heat Removal System of Indian Prototype Fast Breeder Reactor is required to operate with different success criteria during the specified mission time on account of steady decline in decay heat produced by the reactor core. In this paper, Markov analysis is carried out to evaluate the availability of the system under both continuous and periodic monitoring schemes. The study estimates the upper bound and lower bound for mean unavailability of SGDHR system for the specified mission time. Sensitivity analysis of the system attributable to important parameters is also carried out. The study provides a comprehensive approach to model scenarios with time dependent success criteria and provides an insight on the factors affecting availability of such systems

  17. FIP Bias Evolution in a Decaying Active Region

    Baker, D; Démoulin, P; Yardley, S L; van Driel-Gesztelyi, L; Long, D M; Green, L M

    2015-01-01

    Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode's EUV Imaging Spectrometer (EIS) instrument, we present a series of large-scale, spatially resolved composition maps of active region (AR) 11389. The composition maps show how FIP bias evolves within the decaying AR from 2012 January 4-6. Globally, FIP bias decreases throughout the AR. We analyzed areas of significant plasma composition changes within the decaying AR and found that small-scale evolution in the photospheric magnetic field is closely linked to the FIP bias evolution observed in the corona. During the AR's decay phase, small bipoles emerging within supergranular cells reconnect with the pre-existing AR field, creating a pathway along which photospheric and coronal plasmas can mix. The mixing time scales are shorter than those of plasma enrichment processes. Eruptive activity also results in shifting the FIP bias closer to photospheric in the affected areas. Final...

  18. Thermal Capacitance (Slug) Calorimeter Theory Including Heat Losses and Other Decaying Processes

    Hightower, T. Mark; Olivares, Ricardo A.; Philippidis, Daniel

    2008-01-01

    A mathematical model, termed the Slug Loss Model, has been developed for describing thermal capacitance (slug) calorimeter behavior when heat losses and other decaying processes are not negligible. This model results in the temperature time slope taking the mathematical form of exponential decay. When data is found to fit well to this model, it allows a heat flux value to be calculated that corrects for the losses and may be a better estimate of the cold wall fully catalytic heat flux, as is desired in arc jet testing. The model was applied to the data from a copper slug calorimeter inserted during a particularly severe high heating rate arc jet run to illustrate its use. The Slug Loss Model gave a cold wall heat flux 15% higher than the value of 2,250 W/sq cm obtained from the conventional approach to processing the data (where no correction is made for losses). For comparison, a Finite Element Analysis (FEA) model was created and applied to the same data, where conduction heat losses from the slug were simulated. The heat flux determined by the FEA model was found to be in close agreement with the heat flux determined by the Slug Loss Model.

  19. Analysis of a convection loop for GFR post-LOCA decay heat removal

    A computer code (LOCA-COLA) has been developed at MIT for steady state analysis of convective heat transfer loops. In this work, it is used to investigate an external convection loop for decay heat removal of a post-LOCA gas-cooled fast reactor (GFR). The major finding is that natural circulation cooling of the GFR is feasible under certain circumstances. Both helium and CO2 cooled system components are found to operate in the mixed convection regime, the effects of which are noticeable as heat transfer enhancement or degradation. It is found that CO2 outdoes helium under identical natural circulation conditions. Decay heat removal is found to have a quadratic dependence on pressure in the laminar flow regime and linear dependence in the turbulent flow regime. Other parametric studies have been performed as well. In conclusion, convection cooling loops are a credible means for GFR decay heat removal and LOCA-COLA is an effective tool for steady state analysis of cooling loops. (authors)

  20. Specialists' meeting on evaluation of decay heat removal by natural convection

    Decay heat removal by natural convection (DHRNC) is essential to enhancing the safety of liquid metal fast reactors (LMFRs). Various design concepts related to DHRNC have been proposed and experimental and analytical studies have been carried out in a number of countries. The purpose of this Specialists' Meeting on 'Decay Heat Removal by Natural Convection' organized by the International Working Group on Fast Reactors IAEA, is to exchange information about the state of the art related to methodologies on evaluation of DHRNC features (experimental studies and code developments) and to discuss problems which need to be solved in order to evaluate DHRNC properly and reasonably. The following main topical areas were discussed by delegates: Overview; Experimental studies and code validation; Design study. Two main DHR systems for LMFR are under consideration: (i) direct reactor auxiliary cooling system (DRACS) with immersed DFIX in main vessel, intermediate sodium loop and sodium-air heat exchanger; and (ii) auxiliary cooling system which removes heat from the outside surface of the reactor vessel by natural convection of air (RVACS). The practicality and economic viability of the use of RVACS is possible up to a modular type reactor or a middle size reactor based on current technology. For the large monolithic plant concepts DRACS is preferable. The existing experimental results and the codes show encouraging results so that the decay heat removal by pure natural convection is feasible. Concerning the objective, 'passive safety', the DHR by pure natural convection is essential feature to enhance the reliability of DHR

  1. Study on a decay heat removal system of light water reactors using air coolers

    In the present work, a passive decay heat removal system for light water reactors (LWRs) based on a new concept is studied referring to an air cooling system (ACS) of the fast breeder reactor Monju. The present study will contribute to the reduction of severe accident risks of nuclear power plants. In this system, a blower for an air cooler (AC) is operated using the rotation of a small steam turbine by generated steam in order to cool heat transfer tubes by forced convection of air. The purpose of the present work is to investigate the plant transient caused by a station blackout (SBO) using the plant system code NETFLOW++ and decay heat removal characteristics. A calculation model is the Advanced Boiling Water Reactor (ABWR) in Japan. (author)

  2. Near-term decay heat and age of spent fuel in commercial power reactor inventories

    Projections based upon utility supplied data indicate that several commercial nuclear power reactors will require additional spent fuel storage capacity. These storage needs are beyond those which currently exist in the reactor spent fuel storage pools. A key parameter needed to design out-of-pool or consolidated storage capacity to handle these needs is the decay heat of the spent fuel to be stored. Calculations of the heat of the additional spent fuel requiring storage have been made. These calculations indicate small differences in the decay heat of the selected fuel assemblies depending upon whether the oldest or the coldest fuel in the existing inventory is selected first for out-of-pool or consolidated storage

  3. Detailed processes accompanying the decay of an active region

    High resolution (better than 1'') magnetograms obtained at the Sacramento Peak Vacuum Tower Telescope were used to study the decay of a small active region. The reduction process allows one to match intensity and magnetic pictures exactly. Some of the main results are: (i) The granulation massages a magnetic pore, probably inducing its fragmentation. The supergranules get rid of the decayed pieces transporting them away from the pore. (ii) Magnetic flux is removed from the photosphere through its submergence. (author). 5 figs., 10 refs

  4. Evaluation of Heat Removal Performance of Passive Decay Heat Removal system for S-CO{sub 2} Cooled Micro Modular Reactor

    Moon, Jangsik; Lee, Jeong Ik; Jeong, Yong Hoon [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    The modular systems is able to be transported by large trailer. Moreover, dry cooling system is applied for waste heat removal. The characteristics of MMR takes wide range of construction area from coast to desert, isolated area and disaster area. In MMR, Passive decay heat removal system (PDHRS) is necessary for taking the advantage on selection of construction area where external support cannot be offered. The PDHRS guarantees to protect MMR without external support. In this research, PDHRS of MMR is introduced and decay heat removal performance is analyzed. The PDHRS guarantees integrity of reactor coolant system. The high level of decay heat (2 MW) can be removed by PDHRS without offsite power.

  5. Relationship between computed ANSI/ANS-5.1 and ORIGEN-S decay heat powers for BWR LOCA safety analysis

    The decay heat power fraction computed using ANSI/ANS-5.1-1979 with CASMO-4 decay heat parameters is compared with the decay heat power fraction computed using ANSI/ANS-5.1-1979 with ORIGEN-S decay heat parameters. The comparison indicates that the ORIGEN-based ANS-5.1 total decay power fraction appears very close to the CASMO-based ANS-5.1 total decay power fraction due to compensating effect between fission-product decay heat power fraction and U-239 and Np-239 decay heat power fraction, although the CASMO-4 fission fractions and U-238 neutron capture ratio are considered more accurate than the ORIGEN-S fission fractions and U-238 neutron capture ratio. Therefore, it seems acceptable to calculate the total decay heat fraction using ANSI/ANS-5.1-1979 with ORIGEN-S decay heat parameters. This result is useful, since ORIGEN-S /SCALE 5.1 are easier to run than CASMO-4. The decay heat power fraction computed using ANSI/ANS-5.1-1979 is also compared with the decay heat power fraction computed using ORIGEN-S directly. The comparison indicates that the ORIGEN-S total decay heat power fraction is much smaller than the corresponding ANS 5.1 total decay heat power fraction, which is due to the fact that the ORIGEN-S fission-product decay heat power fraction is much smaller than the corresponding ANS 5.1 fission-product decay heat power fraction. This demonstrates that the total decay heat power fraction calculated using ORIGEN-S directly is not conservative and that ANSI/ANS-5.1 must be used to calculate the total decay heat power fraction for LOCA safety analysis. (author)

  6. Activation product decay data: UKPADD-2 data files

    The decay data of various radionuclides have been evaluated on the basis of a series of well-defined specifications and the requirements of the UK nuclear power, fuel reprocessing and waste management programmes. These radionuclides are primarily activation products and standards that are commonly used in gamma-ray spectroscopy. Recommended data include half-life, branching fractions, alpha, beta and gamma-ray energies and emission probabilities, total decay energy, mean alpha, beta and gamma energies, internal conversion coefficients, and all associated uncertainties. Computer-based files have been generated in ENDF-6 format, including lists of the references used to produce the proposed decay scheme and comments that identify any inadequacies. (author)

  7. Approximation of the decay of fission and activation product mixtures

    The decay of the exposure rate from a mixture of fission and activation products is a complex function of time. The exact solution of the problem involves the solution of more than 150 tenth order Bateman equations. An approximation of this function is required for the practical solution of problems involving multiple integrations of this function. Historically this has been a power function, or a series of power functions, of time. The approach selected here has been to approximate the decay with a sum of exponential functions. This produces a continuous, single valued function, that can be made to approximate the given decay scheme to any desired degree of closeness. Further, the integral of the sum is easily calculated over any period. 3 refs

  8. Decay heat calculations with the CEA radioactivity data bauk and the code PEPIN

    The CEA radioactivity data bank, has been updated mainly from ENSDF and from some recent experimental results. This library contains the decay data for about 700 fission products (F.P.), 220 actinides and more than 1400 other nuclides. A comparison between our data and ENDF/B5 is shown for the fission products. The fission products part of this library is currently used for shielding and decay heat calculations with the PEPIN code. Calculations and spectral comparisons of the available experiments (Dickens, Lott, Yarmell ...) and other recent calculations is made for thermal fission of 235U and 239Pu using our data bank as input

  9. Experimental studies on natural circulation decay heat removal in Japan Sodium Cooled Fast Reactor (JSFR)

    Fully natural circulation system is adopted in a decay heat removal system (DHRS) of the designs of Japan Sodium Cooled Fast Reactor (JSFR). Several investigations of experiments and simulation methods on this DHRS were performed. Water experiments were carried out for the primary heat transportation system including a reactor vessel and heat exchangers of DHRS using a 1/10 model. As for the DHRS loop, sodium experiments were carried out, especially for a heat exchanger installed in an Intermediate Heat Exchanger (IHX). Here, several results of the sodium experiments were described. Transient characteristics during the start up in the air system of the air cooler, secondary loop of DHRS, and the primary loop were examined by the sodium experiments. Smooth increases of natural circulation flow rates in all systems of air and sodium were confirmed. Verifications of numerical simulation methods are planned based on the water and sodium experiments in this investigation plan. (author)

  10. Study on decay heat removal characteristics by natural circulation for top entry loop-type FBR

    The thermal-hydraulic circulation characteristics of a top entry loop-type FBR are studied experimentally with a 1/8 scaled three-loop model using water as the working fluid. The model is designed to simulate reactor decay heat removal operations including natural circulation mode as well as three types of decay heat removal systems, a direct reactor auxiliary cooling system (DRACS) with a direct heat exchangers immersed in a hot plenum of a reactor vessel (Immersed type DRACS), a DRACS with DHXs penetrating from a hot plenum to a cold plenum of a reactor vessel (Penetrating type DRACS) and a primary reactor auxiliary cooling system (PRACS). The feasibility of reactor decay heat removal operations including natural circulation mode of a top entry loop-type FBR is confirmed based on the experimental results. The natural circulation performance of the Immersed type DRACS is compared with that of the PRACS for the water test results. The results are used to evaluate the accuracy of the one-dimensional flow-network analysis codes and the multi-dimensional thermal-hydraulic analysis code. The analytical results are generally in good agreement with the measurements. (author)

  11. Decay Heat Removal and Transient Analysis in Accidental Conditions in the EFIT Reactor

    Giacomino Bandini

    2008-01-01

    Full Text Available The development of a conceptual design of an industrial-scale transmutation facility (EFIT of several 100 MW thermal power based on accelerator-driven system (ADS is addressed in the frame of the European EUROTRANS Integral Project. In normal operation, the core power of EFIT reactor is removed through steam generators by four secondary loops fed by water. A safety-related decay heat removal (DHR system provided with four independent inherently safe loops is installed in the primary vessel to remove the decay heat by natural convection circulation under accidental conditions which are caused by a loss-of-heat sink (LOHS. In order to confirm the adequacy of the adopted solution for decay heat removal in accidental conditions, some multi-D analyses have been carried out with the SIMMER-III code. The results of the SIMMER-III code have been then used to support the RELAP5 1D representation of the natural circulation flow paths in the reactor vessel. Finally, the thermal-hydraulic RELAP5 code has been employed for the analysis of LOHS accidental scenarios.

  12. Compilation and review of loss of decay heat removal during reactor shutdown in PWRs

    This report provides review of the U.S.NRC guidances (Information Notice, Generic Letter, Bulletin) related to loss of decay heat removal during reactor shutdown in PWRs. Referring to the U.S.NRC's Licensee Event Reports (LERs), we also identify events involving actual or potential loss of decay heat removal which occurred in the period from the second half of 1990 to the end of 1992, summarize event description, causes and actions taken for each event, and analyze the direct and root causes. Compilation and review of the U.S.NRC guidances indicate that 15 documents have been issued for loss of decay heat removal event after 1980, most of which pointed out the problems concerning operating procedures of residual heat removal during reduced inventory conditions, procedure and/or administration for maintenance and reactor water level instrumentation. Although many actions taken according to the U.S.NRC guidances have decreased the number of such events, the fact that one or more documents per year have been issued after 1986 implies more importance of such events than before. Review of recent events shows that the primary direct cause has been 'vortexing' or 'air entrainment' due to lowering reactor water level too far or loss of coolant. As for root causes, it is found that most of events resulted from human factors such as procedural deficiencies and personnel errors. This report is a sequel to our previous report, JAERI-M 91-143 (Analysis of Operating Experience Data in Nuclear Power Plants - Loss of Decay Heat Removal during Reactor Shutdown -). (author)

  13. Radiotoxicity and decay heat power of spent nuclear fuel of VVER type reactors at long-term storage.

    Bergelson, B R; Gerasimov, A S; Tikhomirov, G V

    2005-01-01

    Radiotoxicity and decay heat power of the spent nuclear fuel of VVER-1000 type reactors are calculated during storage time up to 300,000 y. Decay heat power of radioactive waste (radwaste) determines parameters of the heat removal system for the safe storage of spent nuclear fuel. Radiotoxicity determines the radiological hazard of radwaste after its leakage and penetration into the environment. PMID:16381764

  14. Experimental study on a heat pipe towards in-core decay heat removal control rod

    A novel in-core heat removal concept can be adopted in control rods for passive safety of nuclear power plants. The new concept is featured by a passive heat transfer device called heat pipe and combined with control rod. As the first step for this concept, stainless steel 316L heat pipes were tested in terms of heat removal capability under the same diameter condition with an actual control rod in a typical PWR. It has outer diameter of 3/4 inch (17.4 mm inner diameter), and the length of 1000 mm. Also, the capillary-driven heat pipe was compared with a bare tube with same diameter without wick structures called thermosyphon. As the results, heat transfer coefficients of the heat pipe were ∼34% higher than those of thermosyphon. The results were compared with existing correlations and a CFD analysis. The overall heat transfer characteristics of heat pipes such as thermal resistances were checked for potential uses in terms of in-core heat removal. (author)

  15. ALPHA - The long-term passive decay heat removal and aerosol retention program

    The Paul Scherrer Institute initiated the major new experimental and analytical program ALPHA in 1990. The program is aimed at understanding the long-term decay heat removal and aerosol questions for the next generation of Passive Light Water Reactors. The ALPHA project currently includes four major items: the large-scale, integral system behaviour test facility PANDA, which will be used to examine multidimensional effects of the SBWR decay heat removal system; an investigation of the thermal hydraulics of natural convection and mixing in pools and large volumes (LINX); a separate-effects study of aerosols transport and deposition in plenum and tubes (AIDA); while finally, data from the PANDA facility and supporting separate effects tests will be used to develop and qualify models and provide validation of relevant system codes. The paper briefly reviews the above four topics and current status of the experimental facilities. (author). 3 refs, 12 figs

  16. Decay Heat Removal in GEN IV Gas-Cooled Fast Reactors

    The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs) is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR) in a GEN IV direct-cycle gas-cooled fast reactor (GFR) which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  17. Evaluation on decay heat removal capability of isolation condenser for depressurization and cooling system, July 2014

    In this study, we aimed to quantitatively evaluate cooling capacity of isolation condenser (IC) for core cooling in Fukushima Daiichi Nuclear Plant Unit 1. In order to evaluate cooling capacity, decay heat emitted from fuels in reactor core was calculated. We used the data of nuclear fuel and rated thermal power which is released by TEPCO. We analyzed IC with TRAC code. We made an experiment in order to check IC's input data. Because analysis data is close to experimental data, we made sure validity of input data. We analyzed IC under conditions which are recorded when IC started up and tsunami rushed toward plant. As a result of analysis, we confirmed that cooling capacity exceed decay heat under both conditions. In conclusion, IC had a capability to prevent core meltdown accident in Fukushima Daiichi Nuclear Plant Unit 1. (author)

  18. Online calculation of the decay heat of assemblies at the Fast Flux Test Facility

    The Fast Flux Test Facility (FFTF) is utilized by the US Department of Energy and the international community as a fast reactor research tool. Its use includes, among other things, the irradiation testing of nuclear reactor fuels and materials required for the development of commercial liquid metal reactors. The decay heat rate of assemblies irradiated in the FFTF is an important parameter in establishing the transportation, examination, and storage of irradiated assemblies. The decay heat program which is maintained on a Cray super computer along with a Symphony speadsheet program running on a personal computer (PC) were created to accommodate this need. This unique synthesis provides a method of combing the capabilities of a mainframe computer with those of a PC

  19. Study of Nuclear Decay Data Contribution to Uncertainties in Heat Load Estimations for Spent Fuel Pools

    Ferroukhi, H.; Leray, O.; Hursin, M.; Vasiliev, A.; Perret, G.; Pautz, A.

    2014-04-01

    At the Paul Scherrer Institut (PSI), a methodology for nuclear data uncertainty propagation in CASMO-5M (C5M) assembly calculations is under development. This paper presents a preliminary application of this methodology to C5M decay heat calculations. Applying a stochastic sampling method, nuclear decay data uncertainties are first propagated for the cooling phase only. Thereafter, the uncertainty propagation is enlarged to gradually account for cross-section as well as fission yield uncertainties during the depletion phase. On that basis, assembly heat load uncertainties as well as total uncertainty for the entire pool are quantified for cooling times up to one year. The relative contributions from the various types of nuclear data uncertainties are in this context also estimated.

  20. Decay Heat Removal in GEN IV Gas-Cooled Fast Reactors

    Lap-Yan Cheng

    2009-01-01

    Full Text Available The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR in a GEN IV direct-cycle gas-cooled fast reactor (GFR which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  1. Reliability of the Decay Heat Removal System of Phenix, Concepts and Qualitative Reliability Analysis

    The decay heat removal in the Phenix Reactor has been designed with high level of safety and redundancy so that it should exist at least one way of removal whatever incident would be generated. In the following paragraph, we indicate the principal criteria used in the design, the different ways of operating and the global and qualitative reliability analysis in order to show the high degree of safety

  2. An automated software for analysis of experimental data on decay heat from spent nuclear fuel

    Llerena Herrera, Isbel

    2012-01-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has developed a method for final disposal of spent nuclear fuel. This technique requires accurate measurement of the residual decay heat of every assembly. For this purpose, depletion codes as well as calorimetric and gamma-ray spectroscopy experimental methods have been developed and evaluated. In this work a prototype analysis tool has been developed to automate the analysis of both calorimetric and gamma-ray spectroscopy measureme...

  3. Fast neutron reactor safety. Reliability analysis of Phenix decay heat removal function

    This paper presents a reliability analysis of the Phenix decay heat removal function. After summarizing analysis results of sequences leading to failure of this function, the main steps in a probabilistic risk assessment are described: computation of reliability and maintenance parameters for the various systems involved, followed by probabilistic analysis of failure sequences. The extent to which the various systems contribute to the total risk is analyzed. Certain maintenance recommendations were made accordingly

  4. Reliability analysis of safety grade decay heat removal system of Indian prototype fast breeder reactor

    The 500 MW Indian pool type Prototype Fast Breeder Reactor (PFBR), is provided with two independent and diverse Decay Heat Removal (DHR) systems viz., Operating Grade Decay Heat Removal System (OGDHRS) and Safety Grade Decay Heat Removal System (SGDHRS). OGDHRS utilizes the secondary sodium loops and Steam-Water System with special decay heat removal condensers for DHR function. The unreliability of this system is of the order of 0.1-0.01. The safety requirements of the present generation of fast reactors are very high, and specifically for DHR function the failure frequency should be less than ∼1E-7/ry. Therefore, a passive SGDHR system using four completely independent thermo-siphon loops in natural convection mode is provided to ensure adequate core cooling for all Design Basis Events. The very high reliability requirement for DHR function is achieved mainly with the help of SGDHRS. This paper presents the reliability analysis of SGDHR system. Analysis is performed by Fault Tree method using 'CRAFT' software developed at Indira Gandhi Centre for Atomic Research. This software has special features for compact representation and CCF analysis of high redundancy safety systems encountered in nuclear reactors. Common Cause Failures (CCF) are evaluated by β factor method. The reliability target for SGDHRS arrived from DHR reliability requirement and the ultimate number of demands per year (7/y) on SGDHRS is that the failure frequency should be ≤1.4E-8/de. Since it is found from the analysis that the unreliability of SGDHRS with identical loops is 5.2E-6/de and dominated by leak rates of components like AHX, DHX and sodium dump and isolation valves, options with diversity measures in important components were studied. The failure probability of SGDHRS for a design consisting of 2 types of diverse loops (Diverse AHX, DHX and sodium dump and isolation valves) is 2.1E-8/de, which practically meets the reliability requirement

  5. Radioactivity and decay heat generation in precambrian magmatic rocks (with the South Pamirs as an example)

    The evaluation of the heat generation share in the results of the long-living radioactive elements (RAE) decay in the Earth surface layers is accomplished on the basis of the data on the uranium and thorium concentration in the precambrian magmatic rocks of the South Pamirs. It was supposed by the calculations, that the value of the heat flux, generated by the rocks, is determined mainly by the RAE content in the Earth upper layer crust itself of 10-15 km. It is shown that the radioheat generation share is within the range of 5-10% from the measured values of the geothermal flows

  6. Decay heat removal under boiling condition in a pin-bundle geometry

    Decay heat removal capability under boiling condition was investigated using an electrically heated 37-pin bundle test section. The flow was driven by natural circulation force of the out-of-pile sodium loop SIENA in O-arai Engineering Center, PNC. As the heater power was increased, the two-phase flow regime changed from bubbly flow to slug flow and then to annular or annular mist flow. In 15 runs, dry-out was not observed in the average exit quality region of less than 0.5. The results indicated the existance of a large ''boiling window'' for low flow rate and low power conditions. (author)

  7. Meeting of Specialists on the Reliability of Decay Heat Removal Systems for Fast Reactors. Summary Report

    The Specialists Meeting on Reliability of Decay Heat Removal Systems proposed for Fast Reactors was sponsored by the UKAEA Safety & Reliability Directorate and held at Harwell between 28th April and 1st May, 1975. The meeting was attended by delegates from six countries - (USA, Federal Republic of Germany, France, Japan, USSR and the UK). A list of participants is included in an Appendix to this report. The subject matter of the meeting was concerned with the degree to which the ability to maintain decay heat removal from a fast reactor after shutdown in normal and abnormal circumstances could be guaranteed by design provisions and substantiated by reliability analysis techniques, operational testing etc. Consideration of conditions prevailing after a hypothetical core melt down incident were not included in the subject matter. The deliberations of the meeting were focussed at each working session on a defined theme and its dependant topics as shown in the detailed Agenda included in this report. Although provision had been made in the Agenda for a limited amount of discussion of the decay heat rejection problems of Gas Cooled Fast Reactors, delegates had no contributions to offer on this subject. During each session a Recording Secretary prepared a summary of the main points made by national delegates and of the resulting recommendations and conclusions. These draft summaries were made available to delegates during subsequent sessions of the meeting and approved by them for inclusion in the Summary, General Conclusions and Recommendations provided under Table of Contents (item 3 and 4)

  8. Testing JEFF-3.1.1 and ENDF/B-VII.1 Decay and Fission Yield Nuclear Data Libraries with Fission Pulse Neutron Emission and Decay Heat Experiments

    Cabellos, O.; de Fusco, V.; Diez de la Obra, C. J.; Martinez, J. S.; Gonzalez, E.; Cano-Ott, D.; Alvarez-Velarde, F.

    2014-04-01

    The aim of this work is to test the present status of Evaluated Nuclear Decay and Fission Yield Data Libraries to predict decay heat and delayed neutron emission rate, average neutron energy and neutron delayed spectra after a neutron fission pulse. Calculations are performed with JEFF-3.1.1 and ENDF/B-VII.1, and these are compared with experimental values. An uncertainty propagation assessment of the current nuclear data uncertainties is performed.

  9. Physical distributions of radon decay chain activities in air

    The distribution of short-lived radon decay chain activities in air - in time, space and on aerosols - determines their exposure potential and measurement thereof. The radioactive decay constants and flow variables in a flow system combine, yielding activity concentration distributions and ratios of concentrations characteristic of the flow scheme, its source(s) and sink(s). The clock of 'internal' decay constants allows the unraveling of characteristics of the flow scheme from activity concentration measurements of individual members of a decay chain. Basic flow string calculations are shown. These can be assembled to define or simulate concentrations in a single- or multiple-compartment flow network. Response calculations to single- and multiple-step, or continuous changes in sources and sinks yield time-, spatial- and attachment-distributions. For the short-lived 222Rn and 212Pb decay chains the decay constants of the shorter-lived progeny in relation to the parent impose air activity ratios on successive chain members. Ratio limits had been used in the past to improve older grab-sampling- or integral gross-alpha measurement procedures for assessing exposure level. Assessment of individual concentrations, ratios and their distributions enables unravelling of dynamic flow systems, with restriction from the range of the parameters of flow and decay. An activity measuring instrument by itself represents a flow system with a response time distribution. Instrument response correction during continuous or quasi-continuous sampling and continuous spectrometric measurement allows far more accurate time-resolved measurement evaluation of continuously varying air concentrations, than previously attainable. Strong diurnal or even shorter (≤ 1 hr) changes probably are the norm in indoor and outdoor air activity concentrations. A mere average response evaluation, as used in steady state instrument calibration, and using less efficient instruments, is usually inadequate for

  10. Heating entrepreneur activity in 2003

    According to TTS Institute information, at the end of 2003 there were heating entrepreneurs responsible for fuel management and heat production in at least 212 heating plants in Finland. The number of operative plants increased by 36 from the previous year. At the end of 2003, the total boiler capacity for solid fuel in the plants managed by the heating entrepreneurs exceeded 100 megawatts. The average boiler capacity of the plants was 0.5 megawatts. Heating entrepreneur-ship was most common in west Finland, where 40 percent of the plants are located. There were some 94 heating plants managed by cooperatives or limited companies. Single entrepre neurs or entrepreneur networks consisting of several entrepreneurs were responsible for heat production in 117 plants. Heating entrepreneurs used approximately 290,000 loose cubic metres of forest chips, which is about seven percent of the volume used for heating and power plant energy production in 2003. In addition, the heating entrepreneurs used a total of 40,000 loose cubic metres of other wood fuel and an estimated 20,000 loose cubic metres of sod and milled peat. Municipalities are still the most important customer group for heating entrepreneurs. However, thenumber of private customers is growing. Industrial company, other private company or properly was the main customer already for every fourth plant established during 2003. (orig.)

  11. Decay Heat Analyses after Thermal-Neutron Fission of 235U and 239Pu by SCALE-6.1.3 with Recently Available Fission Product Yield Data

    The heat reaches about 1.5% after one hour and falls to 0.4% after a day. After a week it will be about 0.2%. The reactor, however, still requires further cooling for several years to keep the fuel rods safe. In general, the decay heat in the reactors can be calculated using a summation calculation method, which is simply the sum of the activities of the fission products produced during the fission process and after the reactor shutdown weighted by the mean decay energies. Consequently, the method is strongly dependent on the available nuclear structure data. Nowadays, the method has been implemented in various burnup and depletion programs such as ORIGEN and CINDER. In this study, the decay heat measurements after thermal-neutron fission of 235U and 239Pu have been evaluated by the ORIGEN-S with the decay data and fission product yield libraries included in the SCALE-6.1.3 software package. The new libraries were applied to the decay heat calculations, and the results were compared with those by the ORIGEN reference calculation. The decay heat measurements for very short cooling times after thermal-neutron fission of 235U and 239Pu have been evaluated by the ORIGEN-S summation calculation. The reference calculation results by the latest ORIGEN data libraries of the SCALE-6.1.3 have been validated with the measurements by ORNL and Studsvik. In addition, the generation of the new ORIGEN yield libraries has been completed based on the ENDF/B-VII.1, JEFF-3.1.1, JENDL/FPY-2011, and JENDL-4.0. The new libraries have been successfully applied to the decay heat calculations and comparative analyses have been devoted to verifying the importance of the fission product yield data when estimating the decay heat values for each isotope in a very short time. The decay data library occupies an important position in the ORIGEN summation calculation along with the fission product yield library

  12. Preliminary study of the decay heat removal strategy for the gas demonstrator allegro

    Mayer, Gusztáv, E-mail: gusztav.mayer@energia.mta.hu [Hungarian Academy of Sciences, Centre for Energy Research, P.O. Box 49, H-1525 Budapest (Hungary); Bentivoglio, Fabrice, E-mail: fabrice.bentivoglio@cea.fr [CEA/DEN/DM2S/STMF/LMES, F-38054, Grenoble (France)

    2015-05-15

    Highlights: • Improved decay heat removal strategy was adapted for the 75 MW ALLEGRO MOX core. • New nitrogen injection strategy was proposed for the DEC LOCA transients. • Preliminary CATHARE study shows that most of the investigated transients fulfill criteria. • Further improvements and optimizations are needed for nitrogen injection. - Abstract: The helium cooled Gas Fast Reactor (GFR) is one of the six reactor concepts selected in the frame of the Generation IV International Forum. Since no gas cooled fast reactor has ever been built, a medium power demonstrator reactor – named ALLEGRO – is necessary on the road towards the 2400 MWth GFR power reactor. The French Commissariat à l’Energie Atomique (CEA) completed a wide range of studies during the early stage of development of ALLEGRO, and later the ALLEGRO reactor concept was developed in several European Union projects in parallel with the GFR2400. The 75 MW thermal power ALLEGRO is currently developed in the frame of the European ALLIANCE project. As a result of the collaboration between CEA and the Hungarian Academy of Sciences Centre for Energy Research (MTA EK) new improvements were done in the safety approach of ALLEGRO. A complete Decay Heat Removal (DHR) strategy was devised, relying on the primary circuits as a first way to remove decay heat using pony-motors to drive the primary blowers, and on the secondary and tertiary circuits being able to work in forced or natural circulation. Three identical dedicated loops circulating in forced convection are used as a second way to remove decay heat, and these loops can circulate in natural convection for pressurized transients, providing a third way to remove decay heat in case of accidents when the primary circuit is still under pressure. The possibility to use nitrogen to enhance both forced and natural circulation is discussed. This DHR strategy is supported by a wide range of accident transient simulations performed using the CATHARE2 code

  13. Preliminary study of the decay heat removal strategy for the gas demonstrator allegro

    Highlights: • Improved decay heat removal strategy was adapted for the 75 MW ALLEGRO MOX core. • New nitrogen injection strategy was proposed for the DEC LOCA transients. • Preliminary CATHARE study shows that most of the investigated transients fulfill criteria. • Further improvements and optimizations are needed for nitrogen injection. - Abstract: The helium cooled Gas Fast Reactor (GFR) is one of the six reactor concepts selected in the frame of the Generation IV International Forum. Since no gas cooled fast reactor has ever been built, a medium power demonstrator reactor – named ALLEGRO – is necessary on the road towards the 2400 MWth GFR power reactor. The French Commissariat à l’Energie Atomique (CEA) completed a wide range of studies during the early stage of development of ALLEGRO, and later the ALLEGRO reactor concept was developed in several European Union projects in parallel with the GFR2400. The 75 MW thermal power ALLEGRO is currently developed in the frame of the European ALLIANCE project. As a result of the collaboration between CEA and the Hungarian Academy of Sciences Centre for Energy Research (MTA EK) new improvements were done in the safety approach of ALLEGRO. A complete Decay Heat Removal (DHR) strategy was devised, relying on the primary circuits as a first way to remove decay heat using pony-motors to drive the primary blowers, and on the secondary and tertiary circuits being able to work in forced or natural circulation. Three identical dedicated loops circulating in forced convection are used as a second way to remove decay heat, and these loops can circulate in natural convection for pressurized transients, providing a third way to remove decay heat in case of accidents when the primary circuit is still under pressure. The possibility to use nitrogen to enhance both forced and natural circulation is discussed. This DHR strategy is supported by a wide range of accident transient simulations performed using the CATHARE2 code

  14. Recruitment and activation of mRNA decay enzymes by two ARE-mediated decay activation domains in the proteins TTP and BRF-1

    Lykke-Andersen, Jens; Wagner, Eileen

    2005-01-01

    In human cells, a critical pathway in gene regulation subjects mRNAs with AU-rich elements (AREs) to rapid decay by a poorly understood process. AREs have been shown to directly activate deadenylation, decapping, or 3′-to-5′ exonucleolytic decay. We demonstrate that enzymes involved in all three of these mRNA decay processes, as well as 5′-to-3′ exonucleolytic decay, associate with the protein tristetraprolin (TTP) and its homolog BRF-1, which bind AREs and activate mRNA decay. TTP and BRF-1 ...

  15. Interim storage of solidified fission products from fuel element reprocessing with utilization of obtaining post-decay heat

    It is noted that the out-lined interim store for HRW with industrial utilization of decay heat (production of saturated steam and hydrogen) does include a certain risk potential like any technical plant but that it does not represent a danger to the population living nearby. All internal and external impacts on the store result in safely triggering natural convection cooling. A further emergency cooling system is provided by the water irrigation facility so that obtaining after-heat can be safely removed under all circumstances. Therefore, there are no safety-technology arguments against any realization of the concept presented for interim storage of solidified high-level radio-active wastes. An interim store of this type may be built and operated even in densely populated regions and urban agglomerations. (orig./HP)

  16. Resonance shielding-factor cross-section processing technique validation based on tungsten decay heat experimental data

    This study presents a method to obtain corrected self-shielded radiative capture cross-sections for tungsten isotopes to be used for activation calculations. The approach used is based on the application of the Bondarenko shielding factor method to the 175-group AMPX master library by means of the Bonami-Nitawl scale-4.3 sequence calculation. The ANITA-4M activation code calculates the tungsten radioisotopes production and the decay heat using the self-shielded cross-sections from ENDF/B-VI, JEF-2.2 and JENDL-3.2 data files. Two irradiation scenarios (5 min and 7 h) in the international thermonuclear experimental reactor (ITER)-like neutron flux spectrum defined by the fusion neutron source experiments are analyzed. The unshielded calculations result in discrepancy with experiment up to 70%, while the self-shielding treatment reduces drastically that discrepancy to less than few percents. In comparison to the experimental integral decay heat values provides a validation of the method used to deal with the self-shielding treatment

  17. Resonance shielding-factor cross-section processing technique validation based on tungsten decay heat experimental data

    Cepraga, D G; Frisoni, M

    2000-01-01

    This study presents a method to obtain corrected self-shielded radiative capture cross-sections for tungsten isotopes to be used for activation calculations. The approach used is based on the application of the Bondarenko shielding factor method to the 175-group AMPX master library by means of the Bonami-Nitawl scale-4.3 sequence calculation. The ANITA-4M activation code calculates the tungsten radioisotopes production and the decay heat using the self-shielded cross-sections from ENDF/B-VI, JEF-2.2 and JENDL-3.2 data files. Two irradiation scenarios (5 min and 7 h) in the international thermonuclear experimental reactor (ITER)-like neutron flux spectrum defined by the fusion neutron source experiments are analyzed. The unshielded calculations result in discrepancy with experiment up to 70%, while the self-shielding treatment reduces drastically that discrepancy to less than few percents. In comparison to the experimental integral decay heat values provides a validation of the method used to deal with the sel...

  18. Derivation of decay heat benchmarks for U235 and Pu239 by a least squares fit to measured data

    A least squares technique used by previous authors has been applied to an extended set of available decay heat measurements for both U235 and Pu239 to yield simultaneous fits to the corresponding beta, gamma and total decay heat. The analysis takes account of both systematic and statistical uncertainties, including correlations, via calculations which use covariance matrices constructed for the measured data. The results of the analysis are given in the form of beta, gamma and total decay heat estimates following fission pulses and a range of irradiation times in both U235 and Pu239. These decay heat estimates are considered to form a consistent set of benchmarks for use in the assessment of summation calculations. (author)

  19. Development of numerical analysis methods for natural circulation decay heat removal system applied to a large scale JSFR

    A decay heat removal system utilizing passive natural circulation is applied to a large scale Japan Sodium-cooled Fast Reactor. As preparing for the future licensing, a one-dimensional flow network method and a three-dimensional numerical analysis method were developed to evaluate core cooling capability and thermal transient under decay heat removal modes after reactor trip. The one-dimensional method was applied to a water test simulating the primary system of the reactor, while the three-dimensional method was applied to the water test and a sodium test focusing on the decay heat removal system. The numerical results of both methods have turned out to agree well with the test results. And then the thermal-hydraulic behavior under a typical decay heat removal mode of the reactor has been predicted by the three-dimensional method. (author)

  20. Radiotoxicity and decay heat power of spent uranium-plutonium and thorium fuel at long-term storage

    Changes of radiotoxicity and decay heat power of actinides from spent uranium- plutonium and thorium nuclear fuel of WWER-1000 type reactors at storage during 300 years are investigated in report. (author)

  1. FIP Bias Evolution in a Decaying Active Region

    Baker, D.; Brooks, D. H.; Démoulin, P.; Yardley, S. L.; van Driel-Gesztelyi, L.; Long, D. M.; Green, L. M.

    2015-04-01

    Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode’s EUV Imaging Spectrometer instrument, we present a series of large-scale, spatially resolved composition maps of active region (AR)11389. The composition maps show how FIP bias evolves within the decaying AR during the period 2012 January 4-6. Globally, FIP bias decreases throughout the AR. We analyzed areas of significant plasma composition changes within the decaying AR and found that small-scale evolution in the photospheric magnetic field is closely linked to the FIP bias evolution observed in the corona. During the AR’s decay phase, small bipoles emerging within supergranular cells reconnect with the pre-existing AR field, creating a pathway along which photospheric and coronal plasmas can mix. The mixing timescales are shorter than those of plasma enrichment processes. Eruptive activity also results in shifting the FIP bias closer to photospheric in the affected areas. Finally, the FIP bias still remains dominantly coronal only in a part of the AR’s high-flux density core. We conclude that in the decay phase of an AR’s lifetime, the FIP bias is becoming increasingly modulated by episodes of small-scale flux emergence, i.e., decreasing the AR’s overall FIP bias. Our results show that magnetic field evolution plays an important role in compositional changes during AR development, revealing a more complex relationship than expected from previous well-known Skylab results showing that FIP bias increases almost linearly with age in young ARs.

  2. Validation of the CFD code NEPTUNE for a full scale simulator for decay heat removal systems with in-pool heat exchangers

    Bassenghi, Federica

    2013-01-01

    In the present work, a multi physics simulation of an innovative safety system for light water nuclear reactor is performed, with the aim to increase the reliability of its main decay heat removal system. The system studied, denoted by the acronym PERSEO (in Pool Energy Removal System for Emergency Operation) is able to remove the decay power from the primary side of the light water nuclear reactor through a heat suppression pool. The experimental facility, located at SIET laboratories (PIACE...

  3. Nuclear mass inventory, photon dose rate and thermal decay heat of spent research reactor fuel assemblies

    This document has been prepared to assist research reactor operators possessing spent fuel containing enriched uranium of United States origin to prepare part of the documentation necessary to ship this fuel to the United States. Data are included on the nuclear mass inventory, photon dose rate, and thermal decay heat of spent research reactor fuel assemblies. Isotopic masses of U, Np, Pu and Am that are present in spent research reactor fuel are estimated for MTR, TRIGA and DIDO-type fuel assembly types. The isotopic masses of each fuel assembly type are given as functions of U-235 burnup in the spent fuel, and of initial U-235 enrichment and U-235 mass in the fuel assembly. Photon dose rates of spent MTR, TRIGA and DIDO-type fuel assemblies are estimated for fuel assemblies with up to 80% U-235 burnup and specific power densities between 0.089 and 2.857 MW/kg[sup 235]U, and for fission product decay times of up to 20 years. Thermal decay heat loads are estimated for spent fuel based upon the fuel assembly irradiation history (average assembly power vs. elapsed time) and the spent fuel cooling time

  4. Passive Decay Heat Removal System Options for S-CO{sub 2} Cooled Micro Modular Reactor

    Moon, Jangsik; Jeong, Yong Hoon; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    To achieve modularization of whole reactor system, Micro Modular Reactor (MMR) which has been being developed in KAIST took S-CO{sub 2} Brayton power cycle. The S-CO{sub 2} power cycle is suitable for SMR due to high cycle efficiency, simple layout, small turbine and small heat exchanger. These characteristics of S-CO{sub 2} power cycle enable modular reactor system and make reduced system size. The reduced size and modular system motived MMR to have mobility by large trailer. Due to minimized on-site construction by modular system, MMR can be deployed in any electricity demand, even in isolated area. To achieve the objective, fully passive safety systems of MMR were designed to have high reliability when any offsite power is unavailable. In this research, the basic concept about MMR and Passive Decay Heat Removal (PDHR) system options for MMR are presented. LOCA, LOFA, LOHS and SBO are considered as DBAs of MMR. To cope with the DBAs, passive decay heat removal system is designed. Water cooled PDHR system shows simple layout, but has CCF with reactor systems and cannot cover all DBAs. On the other hand, air cooled PDHR system with two-phase closed thermosyphon shows high reliability due to minimized CCF and is able to cope with all DBAs. Therefore, the PDHR system of MMR will follows the air-cooled PDHR system and the air cooled system will be explored.

  5. Contribution to decay heat calculation: fission product mean beta and gamma assessment

    Following a reactor shutdown, after the fission chain process has completely faded out, a significant quantity of energy (around seven per cent of the total power of the reactor) continues to be generated in the core. This is known as residual power or decay heat. The principal source of this energy is due to the radioactive decay of fission products and is at any time equal to the sum of the powers released by these different nuclei (P = Σ = Pi). Each of the powers Pi is the product of three terms: the concentration of the relevant nuclide, its decay constant and its mean decay energy. The evaluation of the first two term is straightforward. On the other hand the evaluation of the mean energies presents some difficulties due to a lack of data in beta and gamma spectra of some fission products. This study intends, after a critical analysis of the current method of evaluation of the mean energies, to propose a new model for this calculation. The new model tested on several well known nuclides, has been proved correct and precise. It has then been applied to approximatively sixty nuclides among the lesser known ones. The results obtained have lead to a better prediction of both beta and gamma ray components of the residual power. Consequently, this new model, which allows to take into account the lack of beta branching ratio corresponding to the highest levels of the product nucleus in the beta decay reaction, can be adopted to replace the current method, for calculation of the mean energies of fission products, especially in the case of the lesser known nuclides

  6. A value/impact assessment for alternative decay heat removal systems

    A Value/Impact assessment for several alternative decay heat removal systems has been carried out using several measures. The assessment is based on an extension of the methodology presented in the Value/Impact Handbook and includes the effects of uncertainty. The assessment was carried out as a function of site population density, existing plant features, and new plant features. Value/Impact measures based on population dose are shown to be sensitive to site, while measures which monetize and aggregate risk are less so. The latter are dominated by on-site costs such as replacement power costs. (orig.)

  7. Electron heating caused by the ion-acoustic decay instability in a finite-length system

    The ion-acoustic decay instability is investigated for a finite-length plasma with density somewhat below the cutoff density of the electromagnetic driver (napprox.0.7n/sub c/). For this regime, the heating in a very long system can overpopulate the electron tail and cause linear saturation of the low phase velocity electron plasma waves. For a short system, the instability is nonlinearly saturated at larger amplitude by ion trapping. Absorption can be significantly increased by the large-amplitude ion waves. These results compare favorably with microwave experiments

  8. Fission product transport analysis in a loss of decay heat removal accident at Browns Ferry

    This paper summarizes an analysis of the movement of noble gases, iodine, and cesium fission products within the Mark-I containment BWR reactor system represented by Browns Ferry Unit 1 during a postulated accident sequence initiated by a loss of decay heat removal (DHR) capability following a scram. The event analysis showed that this accident could be brought under control by various means, but the sequence with no operator action ultimately leads to containment (drywell) failure followed by loss of water from the reactor vessel, core degradation due to overheating, and reactor vessel failure with attendant movement of core debris onto the drywell floor

  9. Passive decay heat removal by natural air convection after severe accidents

    Erbacher, F.J.; Neitzel, H.J. [Forschungszentrum Karlsruhe Institut fur Angewandte Thermo- und Fluiddynamik, Karlsruhe (Germany); Cheng, X. [Technische Universitaet Karlsruhe Institut fur Stroemungslehre und Stroemungsmaschinen, Karlsruhe (Germany)

    1995-09-01

    The composite containment proposed by the Research Center Karlsruhe and the Technical University Karlsruhe is to cope with severe accidents. It pursues the goal to restrict the consequences of core meltdown accidents to the reactor plant. One essential of this new containment concept is its potential to remove the decay heat by natural air convection and thermal radiation in a passive way. To investigate the coolability of such a passive cooling system and the physical phenomena involved, experimental investigations are carried out at the PASCO test facility. Additionally, numerical calculations are performed by using different codes. A satisfying agreement between experimental data and numerical results is obtained.

  10. Fuel cycle related parametric study considering long lived actinide production, decay heat and fuel cycle performances

    One of the very attractive HTGR reactor characteristics is its highly versatile and flexible core that can fulfil a wide range of diverse fuel cycles. Based on a GTMHR-600 MWth reactor, analyses of several fuel cycles were carried out without taking into account common fuel particle performance limits (burnup, fast fluence, temperature). These values are, however, indicated in each case. Fuel derived from uranium, thorium and a wide variety of plutonium grades has been considered. Long-lived actinide production and total residual decay heat were evaluated for the various types of fuel. The results presented in this papers provide a comparison of the potential and limits of each fuel cycle and allow to define specific cycles offering lowest actinide production and residual heat associated with a long life cycle. (author)

  11. Radioactive decay products in neutron star merger ejecta: heating efficiency and $\\gamma$-ray emission

    Hotokezaka, Kenta; Tanaka, Masaomi; Bamba, Aya; Terada, Yukikatsu; Piran, Tsvi

    2015-01-01

    The radioactive decay of the freshly synthesized $r$-process nuclei ejected in compact binary mergers power optical/infrared macronovae (kilonovae) that follow these events. The light curves depend critically on the energy partition among the different products of the radioactive decay and this plays an important role in estimates of the amount of ejected $r$-process elements from a given observed signal. We study the energy partition and $\\gamma$-ray emission of the radioactive decay. We show that $20$-$50\\%$ of the total radioactive energy is released in $\\gamma$-rays on timescales from hours to a month. The number of emitted $\\gamma$-rays per unit energy interval has roughly a flat spectrum between a few dozen keV and $1$ MeV so that most of this energy is carried by $\\sim 1$ MeV $\\gamma$-rays. However at the peak of macronova emission the optical depth of the $\\gamma$-rays is $\\sim 0.02$ and most of the $\\gamma$-rays escape. The loss of these $\\gamma$-rays reduces the heat deposition into the ejecta and h...

  12. Quantification of modeling uncertainties based on scaling laws in natural circulation decay heat removal

    A Best Estimate Plus Uncertainty (BEPU) analysis is one of the good methods to estimate the uncertainty of phenomenon in a nuclear power plant dynamics. In BEPU analysis, a number of numerical analyses, in which input parameters are varied based on their probabilistic distributions, are carried out to obtain statistical characteristics of the output result. In general, the uncertainty of input parameters, such as a probabilistic distribution form and variance, are estimated based on experimental knowledge and/or engineering judgment. In the present research, we focus on a scaling law (dimensionless number) in constitutive equations from a view point of phenomenological theory. An influence of uncertainty in the dimensionless number and its dependency on BEPU analysis has been investigated. Plant dynamics analyses of Super Safe, Small and Simple (4S) reactor, being developed by Toshiba, are carried out under a natural circulation decay heat removal condition. In the analysis, uncertainties of the dimensionless numbers such as Nusselt, Reynolds, and Prandtl numbers are taken into consideration, as well as an uncertainty of decay heat power. The Latin Hypercube Sampling is applied to determine the input deck set. As a result, it is demonstrated that the parameter dependency on the output result can be revealed by using the dimensionless numbers. (author)

  13. VVER-1000/V320 decay heat analysis, involving TVS-M and TVS-A fuel assemblies

    Petkov, P.V.; Hristov, D.V. [Kozloduy NPP, Vratsa (Bulgaria)

    2007-07-01

    MELCOR-1.8.4 is an integrated computer code, developed for severe accident calculations. It is used primarily for simulation of PWR and BWR types of reactors since the code includes an internal database, suitable for modeling of their cores inventory. Despite similarity between VVER-1000/V320 and PWR, there is still required accounting of specificities of Russian reactor design. MELCOR distinguishes 15 classes, each of them containing chemical elements with similar properties, 12 are involved in radioactive product decay. Part of it appears in the simulation of core decay heat rate after shutdown. In this paper the authors present two reactor core loadings corresponding to fuel assemblies: TVS-M and TVS-A. They have calculated decay heat after reactor shutdown from 100% and 104% of nominal power by SCALE 4.4a package. They also have estimated the amount of generated nuclides. The Newly developed Core Inventory Estimation Tool (CIET), described in this paper, written and tested previously, has been used for the evaluation of core decay heat fractions, distributed over chemical classes. Twelve curves were generated, following the same numerical procedure, implemented in MELCOR for representation of decay heat in W/kg. Comparison of curves shows deviations from the expectations. The total amount of radionuclides, separated in chemical classes, given in MELCOR Computer Code User's was compared to the ones involved in default MELCOR decay heat calculation. The results have confirmed that neglected chemical elements give 0.9% and 1.1% of total core mass for TVS-M and TVS-A and correspondingly 0.5% and 0.6% of total core decay heat.

  14. Technical support for a proposed decay heat guide using SAS2H/ORIGEN-S data

    Major revisions are proposed to the current US Nuclear Regulatory Commission decay heat rate guide entitled ''Regulatory Guide 3.54, Spent Fuel Heat Generation in an Independent Spent Fuel Storage Installation,'' using a new data base produced by the SAS2H analysis sequence of the SCALE-4 system. The data base for the proposed guide revision has been significantly improved by increasing the number and range of parameters that generally characterize pressurized-water-reactor (PWR) and boiling-water-reactor (BWR) spent fuel assemblies. Using generic PWR and BWR assembly models, calculations were performed with each model for six different burnups at each of three separate specific powers to produce heat rates at 20 cooling times in the range of 1 to 110 y. The proposed procedure specifies proper interpolation formulae for the tabulated heat generation rates. Adjustment formulae for the interpolated values are provided to account for differences in initial 235U enrichment and changes in the specific power of a cycle from the average value. Finally, safety factor formulae were derived as a function of burnup, cooling time, and type of reactor. The proposed guide revision was designed to be easier to use. Also, the complete data base and guide procedure is incorporated into an interactive code called LWRARC which can be executed on a personal computer. The report shows adequate comparisons of heat rates computed by SAS2H/ORIGEN-S and measurements for 10 BWR and 10 PWR fuel assemblies. The average differences of the computed minus the measured heat rates of fuel assemblies were -07 ± 2.6% for the BWR and 1.5 ± 1.3% for the PWR. In addition, a detailed analysis of the proposed procedure indicated the method and equations to be valid

  15. Summary report of NEPTUN investigations into the steady state thermal hydraulics of the passive decay heat removal

    During the course of steady state NEPTUN investigations, the effects of different design and operating parameters were studied; in particular: The shell design of the above core sturcture, the core power, the number of decay heat exchangers put in operation, the complete flow path blockage at the primary side of the intermediate heat exchangers, and the fluid level in the primary vessel. The findings of the NEPTUN experiments indicate that the decay heat can be safely removed by natural convection. The interwrapper flow makes an essential contribution to that behavior. The decay heat exchangers installed in the upper plenum cause a thermal stratification associated with a pronounced gradient. The vertical extent of the stratification and the quantity of the gradient are depending on the fact whether a permeable or an impermeable shell covers the above core structure. An increase of the core power or a reduction of the number of decay heat exchangers being in operation leads to a higher temperature level in the primary system but does not alter the global temperature distribution. In the case that no coolant enters the inlet windows at the primary side of the intermediate and decay heat exchangers, the core remains coolable as far as the primary vessel is filled with fluid up to a minimum level. Cold water penetrates from the upper plenum into the core and removes the decay heat. The thermal hydraulic computer code FLUTAN was applied for the three-dimensional numerical simulation of the majority of NEPTUN tests reported here. The comparison of computed against experimental data indicates a qualitatively and quantitatively satisfying agreement of the findings with respect to the field of isotherms as well as the temperature profiles in the upper plenum and within the core region of very complex geometry. (orig./HP)

  16. Radioactive decay products in neutron star merger ejecta: heating efficiency and γ-ray emission

    Hotokezaka, K.; Wanajo, S.; Tanaka, M.; Bamba, A.; Terada, Y.; Piran, T.

    2016-06-01

    The radioactive decay of the freshly synthesized r-process nuclei ejected in compact binary mergers powers optical/infrared macronovae (kilonovae) that follow these events. The light curves depend critically on the energy partition among the different decay products and it plays an important role in estimates of the amount of ejected r-process elements from a given observed signal. We show that 20-50 per cent of the total radioactive energy is released in γ-rays on time-scales from hours to a month. The number of emitted γ-rays per unit energy interval has roughly a flat spectrum between a few dozen keV and 1 MeV so that most of the energy is carried by ˜1 MeV γ-rays. However, at the peak of macronova emission the optical depth of the γ-rays is ˜0.02 and most of the γ-rays escape. The loss of these γ-rays reduces the heat deposition into the ejecta and hence reduces the expected macronova signals if those are lanthanides dominated. This implies that the ejected mass is larger by a factor of 2-3 than what was previously estimated. Spontaneous fission heats up the ejecta and the heating rate can increase if a sufficient amount of transuranic nuclei are synthesized. Direct measurements of these escaping γ-rays may provide the ultimate proof for the macronova mechanisms and an identification of the r-process nucleosynthesis sites. However, the chances to detect these signals are slim with current X-ray and γ-ray missions. New detectors, more sensitive by at least a factor of 10, are needed for a realistic detection rate.

  17. Natural-circulation decay heat removal from an SP-100, 550-kWe power system for a lunar outpost. Final Report

    This research investigated the decay heat removal from the SP-100 reactor core of a 550-kWe power system for a lunar outpost by natural circulation of lithium coolant. A transient model that simulates the decay heat removal loop (DHRL) of the power system was developed and used to assess the system's decay heat removal capability. The effects of the surface area of the decay heat rejection radiator, the dimensions of the decay heat exchanger (DHE) flow duct, the elevation of the DHE, and the diameter of the rise and down pipes in the DHRL on the decay heat removal capability were examined. Also, to determine the applicability of test results at earth gravity to actual system performance on the lunar surface, the effect of the gravity constant (1 g and 1/6 g) on the thermal behavior of the system after shutdown was investigated

  18. Dual active surface heat flux gage probe

    Liebert, Curt H.; Kolodziej, Paul

    1995-02-01

    A unique plug-type heat flux gage probe was tested in the NASA Ames Research Center 2x9 turbulent flow duct facility. The probe was fabricated by welding a miniature dual active surface heat flux gage body to the end of a hollow metal cylindrical bolt containing a metal inner tube. Cooling air flows through the inner tube, impinges onto the back of the gage body and then flows out through the annulus formed between the inner tube and the hollow bolt wall. Heat flux was generated in the duct facility with a Huels arc heater. The duct had a rectangular cross section and one wall was fabricated from 2.54 centimeter thick thermal insulation rigid surface material mounted onto an aluminum plate. To measure heat flux, the probe was inserted through the plate and insulating materials with the from of the gage located flush with the hot gas-side insulation surface. Absorbed heat fluxes measured with the probe were compared with absorbed heat fluxes measured with six water-cooled reference calorimeters. These calorimeters were located in a water-cooled metal duct wall which was located across from the probe position. Correspondence of transient and steady heat fluxes measured with the reference calorimeters and heat flux gage probe was generally within a satisfactory plus or minus 10 percent. This good correspondence was achieved even though the much cooler probe caused a large surface temperature disruption of 1000K between the metal gage and the insulation. However, this temperature disruption did not seriously effect the accuracy of the heat flux measurement. A current application for dual active surface heat flux gages is for transient and steady absorbed heat flux, surface temperature and heat transfer coefficient measurements on the surface of an oxidizer turbine inlet deflector operating in a space shuttle test bed engine.

  19. Improvement of the decay heat removal characteristics of the generation IV gas-cooled fast reactor

    Gas cooling in nuclear power plants (NPPs) has a long history, the corresponding reactor types developed in France, the UK and the US having been thermal neutron spectrum systems using graphite as the moderator. The majority of NPPs worldwide, however, are currently light water reactors, using ordinary water as both coolant and moderator. These NPPs - of the so-called second generation - will soon need replacement, and a third generation is now being made available, offering increased safety while still based on light water technology. For the longer-term future, viz. beyond the year 2030, R and D is currently ongoing on Generation IV NPPs, aimed at achieving closure of the nuclear fuel cycle, and hence both drastically improved utilization of fuel resources and minimization of long-lived radioactive wastes. Like the SFR, the GFR is an efficient breeder, also able to work as iso-breeder using simply natural uranium as feed and producing waste which is predominantly in the form of fission products. The main drawback of the GFR is the difficulty to evacuate decay heat following a loss-of-coolant accident (LOCA) due to the low thermal inertia of the core, as well as to the low coolant density. The present doctoral research focuses on the improvement of decay heat removal (DHR) for the Generation-IV GFR. The reference GFR system design considered in the thesis is the 2006 CEA concept, with a power of 2400 MWth. The CEA 2006 DHR strategy foresees, in all accidental cases (independent of the system pressure), that the reactor is shut down. For high pressure events, dedicated DHR loops with blowers and heat exchangers are designed to operate when the power conversion system cannot be used to provide acceptable core temperatures under natural convection conditions. For de-pressurized events, the strategy relies on a dedicated small containment (called the guard containment) providing an intermediate back-up pressure. The DHR blowers, designed to work under these pressure

  20. Improvement of the decay heat removal characteristics of the generation IV gas-cooled fast reactor

    The majority of NPPs worldwide are currently light water reactors, using ordinary water as both coolant and moderator. (...) For the longer-term future, viz. beyond the year 2030, Research and Development is currently ongoing on Generation IV NPPs, aimed at achieving closure of the nuclear fuel cycle, and hence both drastically improved utilization of fuel resources and minimization of long-lived radioactive wastes. Since the very beginning of the international cooperation on Generation IV, viz. the year 2000, the main research interest in Europe as regards the advanced fast-spectrum systems needed for achieving complete fuel cycle closure, has been for the Sodium-cooled Fast Reactor (SFR). However, the Gas-cooled Fast Reactor (GFR) is currently considered as the main back-up solution. Like the SFR, the GFR is an efficient breeder, also able to work as iso-breeder using simply natural uranium as feed and producing waste which is predominantly in the form of fission products. The main drawback of the GFR is the difficulty to evacuate decay heat following a loss-of-coolant accident (LOCA) due to the low thermal inertia of the core, as well as to the low coolant density. The present doctoral research focuses on the improvement of decay heat removal (DHR) for the Generation-IV GFR. The reference GFR system design considered in the thesis is the 2006 CEA concept, with a power of 2400 MWth. The CEA 2006 DHR strategy foresees, in all accidental cases (independent of the system pressure), that the reactor is shut down. For high pressure events, dedicated DHR loops with blowers and heat exchangers are designed to operate when the power conversion system cannot be used to provide acceptable core temperatures under natural convection conditions. For depressurized events, the strategy relies on a dedicated small containment (called the guard containment) providing an intermediate back-up pressure. The DHR blowers, designed to work under these pressure conditions, need to be

  1. Reactor Decay Heat in 239Pu: Solving the γ Discrepancy in the 4-3000-s Cooling Period

    The β feeding probability of 102,104,105,106,107Tc, 105Mo, and 101Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the γ component of the decay heat for 239Pu in the 4-3000 s range.

  2. Reactor decay heat in 239Pu: solving the γ discrepancy in the 4-3000-s cooling period.

    Algora, A; Jordan, D; Taín, J L; Rubio, B; Agramunt, J; Perez-Cerdan, A B; Molina, F; Caballero, L; Nácher, E; Krasznahorkay, A; Hunyadi, M D; Gulyás, J; Vitéz, A; Csatlós, M; Csige, L; Aysto, J; Penttilä, H; Moore, I D; Eronen, T; Jokinen, A; Nieminen, A; Hakala, J; Karvonen, P; Kankainen, A; Saastamoinen, A; Rissanen, J; Kessler, T; Weber, C; Ronkainen, J; Rahaman, S; Elomaa, V; Rinta-Antila, S; Hager, U; Sonoda, T; Burkard, K; Hüller, W; Batist, L; Gelletly, W; Nichols, A L; Yoshida, T; Sonzogni, A A; Peräjärvi, K

    2010-11-12

    The β feeding probability of (102,104,105,106,107)Tc, 105Mo, and 101Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the γ component of the decay heat for 239Pu in the 4-3000 s range. PMID:21231223

  3. EPRI/WOG analysis of decay heat removal risk at Point Beach

    This paper provides a best-estimate probabilistic analysis of Decay Heat Removal (DHR) risk at the Point Beach nuclear power plant. It includes an evaluation of potential plant modifications proposed by Sandia National Laboratories as pare of the NRC's Unresolved Safety Issue program on DHR requirements (USI A-45). The EPRI/WOG analysis yielded a factor of thirty lower core-damage frequency for the sequences included in the scope of the Sandia study. This analysis also yielded a factor of seven reduction in off-site consequences (over and above the core-damage frequency reduction), and estimates of costs that are 50-400% higher for the various proposed backfit modifications. This evaluation, like the Sandia study, concludes that a dedicated SDHR system is not justifiable for Point Beach on a cost-benefit basis

  4. Experimental investigations on scaled models for the SNR-2 decay heat removal by natural convection

    Scaled water models are used to prove the mode of function of the decay heat removal by natural convection for the SNR-2. The 2D and 3D models were designed to reach the characteristic numbers (Richardson, Peclet) of the reactor. In the experiments on 2D models the position of the immersed cooler (IC) and the power were varied. Temperature fields and velocities were measured. The IC installed as a separate component in the hot plenum resulted in a very complex flow behavior and low temperatures. Integrating the IC in the IHX showed a very simple circulating flow and high temperatures within the hot plenum. With increasing power only slightly rising temperature differences within the core and IC were detected. Recalculations using the COMMIX 1B code gave qualitatively satisfying results. (author)

  5. Reliability study of a special decay heat removal system of a gas-cooled fast reactor demonstrator

    The European roadmap toward the development of generation IV concepts addresses the safety and reliability assessment of the special system designed for decay heat removal of a gas-cooled fast reactor demonstrator (GFRD). The envisaged system includes the combination of both active and passive means to accomplish the fundamental safety function. Failure probabilities are calculated on various system configurations, according to either pressurized or depressurized accident events under investigation, and integrated with probabilities of occurrence of corresponding hardware components and natural circulation performance assessment. The analysis suggests the improvement of measures against common cause failures (CCF), in terms of an appropriate diversification among the redundant systems, to reduce the system failure risk. Particular emphasis is placed upon passive system reliability assessment, being recognized to be still an open issue, and the approach based on the functional reliability is adopted to address the point. Results highlight natural circulation as a challenging factor for the decay heat removal safety function accomplishment by means of passive devices. With the models presented here, the simplifying assumptions and the limited scenarios considered according to the level of definition of the design, where many systems are not yet established, one can conclude that attention has to be paid to the functional aspects of the passive system, i.e. the ones not pertaining to the “hardware” of the system. In this article the results of the analysis are discussed, where the effects of the analytical assumptions, design options, accident managements on the reliability are examined. The design diversity of the components undergoing CCFs can be effective for the improvement and some accident management measures are also possible by making use of the long grace period in GFRD

  6. Reliability study of a special decay heat removal system of a gas-cooled fast reactor demonstrator

    Burgazzi, Luciano, E-mail: luciano.burgazzi@enea.it

    2014-12-15

    The European roadmap toward the development of generation IV concepts addresses the safety and reliability assessment of the special system designed for decay heat removal of a gas-cooled fast reactor demonstrator (GFRD). The envisaged system includes the combination of both active and passive means to accomplish the fundamental safety function. Failure probabilities are calculated on various system configurations, according to either pressurized or depressurized accident events under investigation, and integrated with probabilities of occurrence of corresponding hardware components and natural circulation performance assessment. The analysis suggests the improvement of measures against common cause failures (CCF), in terms of an appropriate diversification among the redundant systems, to reduce the system failure risk. Particular emphasis is placed upon passive system reliability assessment, being recognized to be still an open issue, and the approach based on the functional reliability is adopted to address the point. Results highlight natural circulation as a challenging factor for the decay heat removal safety function accomplishment by means of passive devices. With the models presented here, the simplifying assumptions and the limited scenarios considered according to the level of definition of the design, where many systems are not yet established, one can conclude that attention has to be paid to the functional aspects of the passive system, i.e. the ones not pertaining to the “hardware” of the system. In this article the results of the analysis are discussed, where the effects of the analytical assumptions, design options, accident managements on the reliability are examined. The design diversity of the components undergoing CCFs can be effective for the improvement and some accident management measures are also possible by making use of the long grace period in GFRD.

  7. Analysis of integral circulation and decay heat removal experiments in the lead-bismuth CIRCE facility with RELAP5 code

    In this paper, the results of the post-test analysis of some integral circulation experiments conducted on the lead-bismuth CIRCE facility are presented in comparison with the experimental data. These experiments include the simulation of unprotected loss of flow and unprotected loss of heat sink transients in a pool-type heavy liquid metal reactor. Furthermore, the results of the pre-test analysis of a protected loss of heat sink and flow transient with decay heat removal by a heat exchanger immersed in the pool and operating in natural circulation is presented. All transient analyses have been performed with the RELAP5 thermal-hydraulic code. (author)

  8. CdWO4 scintillating bolometer for Double Beta Decay: Light and Heat anticorrelation, light yield and quenching factors

    Arnaboldi, C.; Beeman, J.W.; Cremonesi, O.; Gironi, L.; M. Pavan; Pessina, G.(Sezione INFN di Milano Bicocca, Milan, Italy); Pirro, S.(INFN-Laboratori Nazionali del Gran Sasso, Assergi, 67010 , L’Aquila, Italy); Previtali, E.

    2010-01-01

    Abstract We report the performances of a 0.51 kg CdWO4 scintillating bolometer to be used for future Double Beta Decay Experiments. The simultaneous read-out of the heat and the scintillation light allows to discriminate between different interacting particles aiming at the disentanglement and the reduction of background contribution, key issue for next generation experiments. We will describe the observed anticorrelation between the heat and the light signal and we will show how t...

  9. Impact of decay heat in concrete on water release/H2 production and its implications to LMRs

    The effects of fission product decay gamma energy deposition in concrete on the rate of water release from concrete is investigated. The results indicate a significant increase in the water release rate when gamma heating is included as compared to surface thermal heating only. Because such water release can lead to hydrogen production, it is concluded that this phenomena should be included in the analysis of the low probability severe accident when appropriate. (author)

  10. BWR spent fuel storage cask performance test. Volume 2. Pre- and post-test decay heat, heat transfer, and shielding analyses

    This report describes the decay heat, heat transfer, and shielding analyses conducted in support of performance testing of a Ridhihalgh, Eggers and Associates REA 2033 boiling water reactor (BWR) spent fuel storage cask. The cask testing program was conducted for the US Department of Energy (DOE) Commercial Spent Fuel Management Program by the Pacific Northwest Laboratory (PNL) and by General Electric at the latters' Morris Operation (GE-MO) as reported in Volume I. The analyses effort consisted of performing pretest calculations to (1) select spent fuel for the test; (2) symmetrically load the spent fuel assemblies in the cask to ensure lateral symmetry of decay heat generation rates; (3) optimally locate temperature and dose rate instrumentation in the cask and spent fuel assemblies; and (4) evaluate the ORIGEN2 (decay heat), HYDRA and COBRA-SFS (heat transfer), and QAD and DOT (shielding) computer codes. The emphasis of this second volume is on the comparison of code predictions to experimental test data in support of the code evaluation process. Code evaluations were accomplished by comparing pretest (actually pre-look, since some predictions were not completed until testing was in progress) predictions with experimental cask testing data reported in Volume I. No attempt was made in this study to compare the two heat transfer codes because results of other evaluations have not been completed, and a comparison based on one data set may lead to erroneous conclusions

  11. Presentation of decay heat removal computer codes used for gas cooled reactors

    For the existing French Magnox type reactors, two computer codes have been developed to analyze the transient after reactor shutdown: - The first one ('GITA', is representative of the short term evolution (less than 2 days) and it includes a refined representation of all the reactor components. - The second one, 'LOTE', has been developed to represent the long term evolution (from 2 days to several months) with a simplified representation of the main components of the reactor. One example of accident simulation is presented for existing Magnox reactor. Moreover, as a part of the French program on the future reactors, an analysis of the modular high temperature has been initiated. 2D and 3D general flow and conduction codes are used for this analysis: - DELFINE is a 2D conduction code including a 1D thermosyphon model, it has been used for decay heat removal analysis. TRIO is a 3D flow code including 3D radiation, conduction and convection heat transfer. It is used for detailed thermal analysis during accidental conditions

  12. A computer code for calculation of radioactive nuclide generation and depletion, decay heat and γ ray spectrum. FPGS90

    In a nuclear reactor radioactive nuclides are generated and depleted with burning up of nuclear fuel. The radioactive nuclides, emitting γ ray and β ray, play role of radioactive source of decay heat in a reactor and radiation exposure. In safety evaluation of nuclear reactor and nuclear fuel cycle, it is needed to estimate the number of nuclides generated in nuclear fuel under various burn-up condition of many kinds of nuclear fuel used in a nuclear reactor. FPGS90 is a code calculating the number of nuclides, decay heat and spectrum of emitted γ ray from fission products produced in a nuclear fuel under the various kinds of burn-up condition. The nuclear data library used in FPGS90 code is the library 'JNDC Nuclear Data Library of Fission Products - second version -', which is compiled by working group of Japanese Nuclear Data Committee for evaluating decay heat in a reactor. The code has a function of processing a so-called evaluated nuclear data file such as ENDF/B, JENDL, ENSDF and so on. It also has a function of making figures of calculated results. Using FPGS90 code it is possible to do all works from making library, calculating nuclide generation and decay heat through making figures of the calculated results. (author)

  13. CFD analysis of decay heat removal scenarios of the lead cooled ELSY reactor

    The lead cooled European reactor concept ELSY is characterized by its innovative, compact design, where all components of the primary loops are located inside the reactor vessel. The vessel includes 8 steam generators and pumps which generate a coolant flux of 126 tons/s. At nominal operation conditions the core releases about 1500 MW converted to an electric power of 600 MW. For the coolant temperatures 400 C at the core inlet and 480 C are envisaged. If the reactor is shut down and the pumps are switched off, the decay heat is removed by isolation condenser (IC) systems acting on the SG secondary circuits. If the IC's are not available, heat removal by 4 dip coolers is foreseen, which can be operated by gravitation driven water flow or by air. Additionally the outer vessel wall is permanently cooled by a RVACS (reactor vessel air cooling) system located between the outer vessel wall and the reactor cavity. The main intention of this work is the investigation of the passive cooling systems which are used for the decay heat removal. The CFD vessel model of about 20 million cells takes advantage of the components symmetry and simulates a 90 deg. section of the reactor. The spatial resolution of the computational grid varies between 5 mm close to walls and 100 mm in undisturbed regions where only small gradients are expected. The core, the pumps and the SG's are simulated with porous media models including volumetric source terms for momentum and energy. For the SG's detailed CFD studies with at least one order of magnitude finer grid resolution are performed in order to obtain data for pressure losses. Solids like pipe walls or the core barrel are taking into account by heat conduction. As the model considers a closed system the coolant flux is controlled by momentum sources of the pumps and frictional losses mainly by the core and the SG's. The simulations are performed as single phase flows, therefore the free lead surface at the unclosed upper part of the vessel

  14. Integrated assessment approach to ensure removal of decay heat with RCW out of service

    In the unusual event that Recirculated Cooling Water System of a CANDU NPP is drained for maintenance or generally incapacitated and the reactor is in the Guaranteed Shutdown State, an alternative source of cooling water is required to remove decay heat. For the Cernavoda Unit 1 NPP, CNE-PROD assessed and proposed a novel arrangement to address this issue, prepared a design, and requested AECL to assess the proposed approach. As part of the assessment, AECL developed and performed an integrated approach that brought together a variety of design, operational, maintenance and safety considerations. First, a simplified hydraulic analysis was performed, the heat removal requirements of the system were reviewed and alternative heat sinks were evaluated. Then, the maintenance and operational implications were considered in detail, using AECL's Systematic Assessment of Maintenance (SAM) process. This included a detailed assessment of failure modes of interest and associated effects (Failure Modes and Effects Analysis). This assessment included consideration of the impact on operational chemistry. In addition, the safety implications (potential for human error and safety consequences of failure) were reviewed. Based upon the system requirements, hydraulic assessment, and maintenance review, several alternatives or improvements to the CNE-PROD proposal were developed. In addition, a number of operational suggestions, as well as additional concerns and considerations were identified. Finally, potential alternative solutions were looked at based upon previous AECL experience. This paper will describe the novel CNE-PROD arrangement and provide an overview of the integrated assessment approach taken by AECL (using Plant Life Management technologies) to evaluate the proposed arrangement and to identify additional considerations. (author)

  15. Experimental and analytical studies for the validation of HTR-VGD and primary cell passive decay heat removal. Supplement. Measurements

    The alternative concept for a modular HTR-reactor design by Siempelkamp, Krefeld, using a prestressed cast iron vessel (VGD) combined with a cast iron/concrete module for the primary cell with integrated passive decay heat removal system was fully qualified with respect to operational and accidental thermal loads. The main emphasis was to confirm and validate the passive decay heat removal capability. An experimental facility (INWA) was designed, instrumented and operated with an appropriate electrical heating system simulating steady-state operational and transient accidental thermal loads. The experiments were accompanied by extensive computations concerning the combination of conductive, radiative and convective energy transport mechanisms in the different components of the VGD/primary cell structures, as well as elastic-plastic stress analyses of the VGD. In addition, a spectrum of potential alternatives for passive energy removed options have been parametrically examined. The experimental data clearly demonstrate that the proposed Siempelkamp-design is able to passively and safely remove the decay heat for operational and accidental conditions without invalidating technological important thermal limits. This also holds in case of failures of both the natural convection system and ultimate heat sink by outside concrete water film cooling. (orig./HP)

  16. Neutronic and thermo-hydraulic analyses of a small, long-life HTGR for passive decay-heat removal

    Since the accident at Fukushima Daiichi Nuclear Power Plant in 2011, design concepts for nuclear reactors have been reconsidered with much greater emphasis placed upon passive systems for decay-heat removal. By considering this issue, the design parameter conditions for high temperature gas-cooled reactors (HTGRs) with passive safety features of decay-heat removal were obtained by residual-heat transfer calculation using equations for fundamental heat transfer mechanisms in our previous works. In the present study, the appropriate size of reactor core for a 100 MWt reactor operating at 1123 K of the initial core temperature was found using the conditions. Consequently, neutronics and thermo-hydraulic analyses for the proposed reactor core were performed and the proper optimizations to control the excess reactivity and flatten the change in power peaking factor during operation were done successfully. By the systematic method to decide the core design which satisfies the condition for passive decay-heat removal, a long-life small HTGR concept whose excess reactivity was small during the operation was shown. The small excess reactivity is a significant advantage from the view point of safety in reactivity accident. (author)

  17. Experimental and analytical studies for the validation of HTR-VGD and primary cell passive decay heat removal. Supplement. Calculations

    The alternative concept for a modular HTR-reactor design by Siempelkamp, Krefeld, using a prestressed cast iron vessel (VGD) combined with a cast iron/concrete module for the primary cell with integrated passive decay heat removal system was fully qualified with respect to operational and accidental thermal loads. The main emphasis was to confirm and validate the passive decay heat removal capability. An experimental facility (INWA) was designed, instrumented and operated with an appropriate electrical heating system simulating steady-state operational and transient accidental thermal loads. The experiments were accompanied by extensive computations concerning the combination of conductive, radiative and convective energy transport mechanisms in the different components of the VGD/primary cell structures, as well as elastic-plastic stress analyses of the VGD. In addition, a spectrum of potential alternatives for passive energy removed options have been parametrically examined. The experimental data clearly demonstrate that the proposed Siempelkamp-design is able to passively and safely remove the decay heat for operational and accidental conditions without invalidating technological important thermal limits. This also holds in case of failures of both the natural convection system and ultimate heat sink by outside concrete water film cooling. (orig./HP)

  18. Correlation of Coronal Plasma Properties and Solar Magnetic Field in a Decaying Active Region

    Ko, Yuan-Kuen; Young, Peter R.; Muglach, Karin; Warren, Harry P.; Ugarte-Urra, Ignacio

    2016-08-01

    We present the analysis of a decaying active region observed by the EUV Imaging Spectrometer on Hinode during 2009 December 7–11. We investigated the temporal evolution of its structure exhibited by plasma at temperatures from 300,000 to 2.8 million degrees, and derived the electron density, differential emission measure, effective electron temperature, and elemental abundance ratios of Si/S and Fe/S (as a measure of the First Ionization Potential (FIP) Effect). We compared these coronal properties to the temporal evolution of the photospheric magnetic field strength obtained from the Solar and Heliospheric Observatory Michelson Doppler Imager magnetograms. We find that, while these coronal properties all decreased with time during this decay phase, the largest change was at plasma above 1.5 million degrees. The photospheric magnetic field strength also decreased with time but mainly for field strengths lower than about 70 Gauss. The effective electron temperature and the FIP bias seem to reach a “basal” state (at 1.5 × 106 K and 1.5, respectively) into the quiet Sun when the mean photospheric magnetic field (excluding all areas physical properties are all positively correlated with each other and the correlation is the strongest in the high-temperature plasma. Such correlation properties should be considered in the quest for our understanding of how the corona is heated. The variations in the elemental abundance should especially be considered together with the electron temperature and density.

  19. Design Of Rectifier Controller For Decay Heat Simulation Using Thermalhydraulic Test Loop

    The reactor thermalhydraulic tast loop permits to study experimentally the thermalhydraulic phenomena in a PWR or PHWR nuclear reactor. The system is design to operate in normal mode, hence the power supplied to the test section will loose totally as soon as the system is shutdown. In this research, the power control system has been modified in order to be able to simulate the decay heat phenomena. The power setting circuit has been modified from the potentiometer circuit to another one using DAC and computer program. This modification is to overcome the slow setting changes caused by the limit of the motor rotation. The test results an absolute error 6.25 kW, that corresponds to the DAC conversion error 0.5 LSB. This error is less than any other general method, that provides error conversion 1 LSB. In term of electrical power, the error value depends on the setting configuration adapted to the maximum power. In this work, the maximum power value is 3.2 MW, which corresponds to the nominal power of the installation. Besides its better precision, this modification provides also a higher speed then the previous system using potentiometer. The smallest sampling time chosen 10 ms is much greater then the DAC time conversion, so the analog signal still well correspond to its digital value

  20. Shutdown Decay Heat Removal analysis of a Westinghouse 3-loop pressurized water reactor: Case study

    This is one of six case studies for USI A-45 Decay Heat Removal (DHR) Requirements. The purpose of this study is to identify any potential vulnerabilities in the DHR systems of a typical Westinghouse 3-loop PWR, to suggest possible modifications to improve the DHR capability, and to assess the value and impact of the most promising alternatives to the existing DHR systems. The systems analysis considered small LOCAs and transient internal initiating events, and seismic, fire, extreme wind, internal and external flood, and lightning external events. A full-scale systems analysis was performed with detailed fault trees and event trees including support system dependencies. The system analysis results were extrapolated into release categories using applicable past PRA phenomenological results and improved containment failure mode probabilities. Public consequences were estimated using site specific CRAC2 calculations. The Value-Impact (VI) analysis of possible alternatives considered both onsite and offsite impacts arriving at several risk measures such as averted population dose out to a 50-mile radius and dollars per person rem averted. Uncertainties in the VI analysis are discussed and the issues of feed and bleed and secondary blowdown are analyzed

  1. Decay heat removal and operator's intervention during a very small LOCA

    Sample calculations were done for KORI-1 to develop a better understanding of what happens after very small LOCA (< or approx.0.05 ftsup(2)). For a water-side break with the break size larger than 0.006ftsup(2), fluid-loss through break exceeds the makeup. If the break sizeis larger than 0.008ftsup(2), decay heat can be completely removed through break. Based on these results, it was concluded that KORI-1 is fairly safe for the whole spectrum of sizes in very small LOCA. However, for the reactor with 9000MWe or 1200MWe, a certain spectrum of sizes in very small LOCA should be carefully considered. In the accident sequence the transition from natural circulation to pool boiling or from pool boiling to natural circulation may be troublesome to the operator or in the safety analysis. Operator's intervension was discussed; primary pump shutoff, HPI pump shutoff, break isolation, and opening relief valve. It was proved that continuous operation of HPI pumps after shutdown will not threaten the integrity of the primary system. (Author)

  2. Shutdown decay heat removal analysis of a Babcock and Wilcox pressurized water reactor: Case study

    This is one of six case studies for USI A-45 Decay Heat Removal (DHR) Requirements. The purpose of this study is to identify any potential vulnerabilities in the DHR systems of a typical Babcock and Wilcox PWR, to suggest possible modifications to improve the DHR capability, and to assess the value and impact of the most promising alternatives to the existing DHR systems. The systems analysis considered small LOCAs and transient internal initiating events, and seismic, fire, extreme wind, internal and external flood, and lightning external events. A full-scale systems analysis was performed with detailed fault trees and event trees including support system dependencies. The system analysis results were extrapolated into release categories using applicable past PRA phenomenological results and improved containment failure mode probabilities. Public consequences were estimated using site specific CRAC2 calculations. The Value-Impact (VI) analysis of possible alternatives considered both onsite and offsite impacts arriving at several risk measures such as averted population dose out to a 50-mile radius and dollars per person rem averted. Uncertainties in the VI analysis are discussed and the issues of feed and bleed and secondary blowdown are analyzed

  3. Uncertainty correlation in stochastic safety analysis of natural circulation decay heat removal of liquid metal reactor

    Since various uncertainties of input variables are involved and nonlinearly-correlated in the Best Estimate (BE) plant dynamics code, it is of importance to evaluate the importance of input uncertainty to the computational results and to estimate the accuracy of the confidence level of the results. In order to estimate the importance and the accuracy, the authors have applied the stochastic safety analysis procedure using the Latin Hypercube sampling method to Liquid Metal Reactor (LMR) natural circulation Decay Heat Removal (DHR) phenomenon in the present paper. 17 input variables are chosen for the analyses and 5 influential variables, which affect the maximum coolant temperature at the core in a short period of time (several tens seconds), are selected to investigate the importance by comparing with the full-scope parametric analysis. As a result, it has been demonstrated that a comparative small number of samples is sufficient enough to estimate the dominant input variable and the confidence level. Furthermore, the influence of the sampling method on the accuracy of the upper tolerance limit (confidence level of 95%) has been examined based on the Wilks' formula. (author)

  4. Numerical investigation of multidimensional natural circulation phenomenon in passive safety systems for decay heat removal in large pools

    Many advanced designs of nuclear reactors adopt a methodology of passive safety systems in which the decay heat generated from a reactor is transferred by natural circulation into large pool of water called the Gravity Driven Water Pool (GDWP). Three-dimensional convection flows develop, which in turn affect the heat transfer process and hence the temperature pattern. The heat transfer process can get compromised by the possible stratification of the temperature. The objective of this study is to investigate the transient multidimensional natural circulation phenomenon in GDWP having total volume of 9247 m3 using open source CFD code (OpenFOAM-2.2). In order to reduce the thermal stratification, various geometrical modifications have been incorporated on the heat exchanger design, such as distributing and submergence of heat source; provision of passive elements such as draft tube. A detailed CFD analysis has confirmed the mitigation of thermal stratification phenomenon. (author)

  5. Development of margin assessment methodology of decay heat removal function against external hazards. (2) Tornado PRA methodology

    Probabilistic Risk Assessment (PRA) for external events has been recognized as an important safety assessment method after the TEPCO's Fukushima Daiichi nuclear power station accident. The PRA should be performed not only for earthquake and tsunami which are especially key events in Japan, but also the PRA methodology should be developed for the other external hazards (e.g. tornado). In this study, the methodology was developed for Sodium-cooled Fast Reactors paying attention to that the ambient air is their final heat sink for removing decay heat under accident conditions. First, tornado hazard curve was estimated by using data recorded in Japan. Second, important structures and components for decay heat removal were identified and an event tree resulting in core damage was developed in terms of wind load and missiles (i.e. steel pipes, boards and cars) caused by a tornado. Main damage cause for important structures and components is the missiles and the tornado missiles that can reach those components and structures placed on high elevations were identified, and the failure probabilities of the components and structures against the tornado missiles were calculated as a product of two probabilities: i.e., a probability for the missiles to enter the intake or outtake in the decay heat removal system, and a probability of failure caused by the missile impacts. Finally, the event tree was quantified. As a result, the core damage frequency was enough lower than 10-10/ry. (author)

  6. BWR spent fuel storage cask performance test. Volume 1. Cask handling experience and decay heat, heat transfer, and shielding data

    This report documents a heat transfer and shielding performance test conducted on a Ridihalgh, Eggers and Associates REA 2023 boiling water reactor (BWR) spent fuel storage cask. The testing effort consisted of three parts: pretest preparations, performance testing, and post-test activities. Pretest preparations included conducting cask handling dry runs and characterizing BWR spent fuel assemblies from Nebraska Public Power District's Cooper Nuclear Station. The performance test matrix included 14 runs consisting of two loadings, two cask orientations, and three backfill environments. Post-test activities included calorimetry and axial radiation scans of selected fuel assemblies, in-basin sipping of each assembly, crud collection, video and photographic scans, and decontamination of the cask interior and exterior

  7. BWR spent fuel storage cask performance test. Volume 1. Cask handling experience and decay heat, heat transfer, and shielding data

    McKinnon, M.A.; Doman, J.W.; Tanner, J.E.; Guenther, R.J.; Creer, J.M.; King, C.E.

    1986-02-01

    This report documents a heat transfer and shielding performance test conducted on a Ridihalgh, Eggers and Associates REA 2023 boiling water reactor (BWR) spent fuel storage cask. The testing effort consisted of three parts: pretest preparations, performance testing, and post-test activities. Pretest preparations included conducting cask handling dry runs and characterizing BWR spent fuel assemblies from Nebraska Public Power District's Cooper Nuclear Station. The performance test matrix included 14 runs consisting of two loadings, two cask orientations, and three backfill environments. Post-test activities included calorimetry and axial radiation scans of selected fuel assemblies, in-basin sipping of each assembly, crud collection, video and photographic scans, and decontamination of the cask interior and exterior.

  8. Radiotoxicity and decay heat power of actinides and fission products of spent nuclear fuel of WWER type reactors at long-term storage

    Time dependence of a power and radiotoxicity of spent nuclear fuel of WWER-1000 reactors at its long-term storage or uniform accumulation in long-term storage on basis of 1 GW of electrical power is investigated. At calculations of decay heat power, the contributions of alpha-, beta-, and gamma- irradiation were taken into account, at calculations of a radiotoxicity - maximum permissible activity of nuclides in air and in water were taken into account. The submitted data can be used by choice of strategy of a long-term storage of spent nuclear fuel of power reactors. (author)

  9. The effect of air leakage and heat exchange on the decay of entrapped air pocket slamming oscillations

    Abrahamsen, Bjørn C.; Faltinsen, Odd M.

    2011-10-01

    The phenomenon studied in this work is that of an air pocket entrapped by a free surface water wave inside a rectangular tank at a high filling level. The wave, which is a gravity wave, is caused by forced horizontal motion which is constructed in a particular way, in order to entrap an air pocket as it approaches the upper left corner of the tank. As the wave touches the roof, the air is compressed and starts to oscillate. The oscillations resemble, to some extent, the free oscillations of an underdamped mass-spring system, where the mass is related to the generalized added mass effect of the water pressure associated with the air pocket oscillations. The stiffness is due to the compressibility of the air. The reason for the damping or, more generally, the decay of the air pocket oscillations is less understood. Air leakage has been proposed as one possible reason for this decay. In this work, the role of air leakage is found not to be the reason for the decay of the air pocket oscillations, because it is not present during major parts of the impact. However, by drilling holes in the roof of the tank, the effect of leakage during the oscillations is proven to cause decay. To explain the physical source of the decay of the oscillations, damping due to heat transfer to and from the air pocket is investigated through an analytical one-dimensional steady-state model. The damping due to heat transfer is observed to play an important role. The obtained understanding of the mechanisms causing the decay of the air-pocket impact at the upper corner is believed to be relevant to other types of impacts, particularly the entrapment of air pockets on walls by breaking waves.

  10. Influence of high burnup on the decay heat power of spent fuel at long-term storage

    Development and application of advanced fuel with higher burnup is now in practice of NPP with light water reactors in an increasing number of countries. High burnup allows to decrease significantly consumption of uranium. However, spent fuel of this type contains increased amount of high active actinides and fission products in comparison with spent fuel of common-type burnup. Therefore extended time of storage, improved cooling system of the storage facility will be required along with more strong radiation protection during storage, transportation and processing. Calculated data on decay heat power of spent uranium fuel of light water VVER-1000 type reactor are discussed in the paper. Long-term storage of discharged fuel during 100000 years is considered. Calculations were made for burnups of 40-70 MW d/kg. In the initial 50-year period of storage, power of fission products is much higher than that of actinides. Power of gamma-radiation is mainly due to fission products. During subsequent storage power of fission products quickly decreases, the main contribution to the power is given by actinides rather than by fission products. (author)

  11. Reliability Assessment of 2400 MWth Gas-Cooled Fast Reactor Natural Circulation Decay Heat Removal in Pressurized Situations

    C. Bassi

    2008-01-01

    Full Text Available As the 2400 MWth gas-cooled fast reactor concept makes use of passive safety features in combination with active safety systems, the question of natural circulation decay heat removal (NCDHR reliability and performance assessment into the ongoing probabilistic safety assessment in support to the reactor design, named “probabilistic engineering assessment” (PEA, constitutes a challenge. Within the 5th Framework Program for Research and Development (FPRD of the European Community, a methodology has been developed to evaluate the reliability of passive systems characterized by a moving fluid and whose operation is based on physical principles, such as the natural circulation. This reliability method for passive systems (RMPSs is based on uncertainties propagation into thermal-hydraulic (T-H calculations. The aim of this exercise is finally to determine the performance reliability of the DHR system operating in a “passive” mode, taking into account the uncertainties of parameters retained for thermal-hydraulical calculations performed with the CATHARE 2 code. According to the PEA preliminary results, exhibiting the weight of pressurized scenarios (i.e., with intact primary circuit boundary for the core damage frequency (CDF, the RMPS exercise is first focusing on the NCDHR performance at these T-H conditions.

  12. Dynamic simulation of the air-cooled decay heat removal system of the German KNK-II experimental breeder reactor

    A Dump Heat Exchanger and associated feedback control system models for decay heat removal in the German KNK-II experimental fast breeder reactor are presented. The purpose of the controller is to minimize temperature variations in the circuits and, hence, to prevent thermal shocks in the structures. The basic models for the DHX include the sodium-air thermodynamics and hydraulics, as well as a control system. Valve control models for the primary and intermediate sodium flow regulation during post shutdown conditions are also presented. These models have been interfaced with the SSC-L code. Typical results of sample transients are discussed

  13. Report on the activities of the decay data evaluation project

    This report summarizes the work of the DDEP collaboration since its establishment in 1994. The aim of this group is to evaluate and propose decay data for approximately 250 radionuclides of interest in various applications. It also presents a projected schedule of nuclear data evaluations for 2002-2003, and the minutes of the DDEP Meeting held at Braunschweig, Germany, May 15, 2001. A sample of a DDEP evaluation is presented in this report. (authors)

  14. Sodium experiment on fully natural circulation systems for decay heat removal in Japan sodium-cooled fast reactor

    Fully natural circulation system is adopted in a decay heat removal system (DHRS) of Japan Sodium Cooled Fast Reactor (JSFR). The DHRS of JSFR consists of one unit of DRACS (direct reactor auxiliary cooling system), which has a dipped heat exchanger in the reactor vessel and two units of PRACS, which has a heat exchanger in a primary-side inlet plenum of IHX in each loop. In this study, the sodium experiments were conducted using a sodium test loop PLANDTL in order to investigate the effect of operation mode on transient behavior of thermal hydraulic in PRACS loop. The experimental results revealed the effect of increasing heat removal capacity of PRACS and the forced flow operation in PRACS loop on the thermal transient in the PRACS loop and natural circulation behavior of PRACS. (author)

  15. Low-latitude coronal holes, decaying active regions and global coronal magnetic structure

    Petrie, Gordon

    2013-01-01

    We study the relationship between decaying active region magnetic fields, coronal holes and the global coronal magnetic structure using Global Oscillations Network Group (GONG) synoptic magnetograms, Solar Terrestrial RElations Observatory (STEREO) extreme ultra-violet (EUV) synoptic maps and coronal potential-field source-surface (PFSS) models. We analyze 14 decaying regions and associated coronal holes occurring between early 2007 and late 2010, four from cycle 23 and 10 from cycle 24. We investigate the relationship between asymmetries in active regions' positive and negative magnetic intensities, asymmetric magnetic decay rates, flux imbalances, global field structure and coronal hole formation. Whereas new emerging active regions caused changes in the large-scale coronal field, the coronal fields of the 14 decaying active regions only opened under the condition that the global coronal structure remained almost unchanged. This was because the dominant slowly-varying, low-order multipoles prevented opposin...

  16. Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003

    In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD+D projects

  17. CFD modeling and thermal-hydraulic analysis for the passive decay heat removal of a sodium-cooled fast reactor

    Research highlights: → The COOLOD/N2 and PARET/ANL codes were used for a steady-state thermal-hydraulic and safety analysis of the 2 MW TRIGA MARK II reactor located at the Nuclear Studies Center of Maamora (CENM), Morocco. → The main objective of this study is to ensure the safety margins of different safety related parameters by steady-state calculations at full power level (2 MW). → The most important conclusion is that all obtained values of DNBR, fuel center and surface temperature, cladding surface temperature and coolant temperature across the hottest channel are largely far to compromise safety of the reactor. - Abstract: In this study, a pool-typed design similar to sodium-cooled fast reactor (SFR) of the fourth generation reactors has been modeled using CFD simulations to investigate the characteristics of a passive mechanism of Shutdown Heat Removal System (SHRS). The main aim is to refine the reactor pool design in terms of temperature safety margin of the sodium pool. Thus, an appropriate protection mechanism is maintained in order to ensure the safety and integrity of the reactor system during a shutdown mode without using any active heat removal system. The impacts on the pool temperature are evaluated based on the following considerations: (1) the aspect ratio of pool diameter to depth, (2) the values of thermal emissivity of the surface materials of reactor and guard vessels, and (3) innerpool liner and core periphery structures. The computational results show that an optimal pool design in geometry can reduce the maximum pool temperature down to ∼551 oC which is substantially lower than ∼627 oC as calculated for the reference case. It is also concluded that the passive Reactor Air Cooling System (RACS) is effective in removing decay heat after shutdown. Furthermore, thermal radiation from the surface of the reactor vessel is found to be important; and thus, the selection of the vessel surface materials with a high emissivity would be a

  18. CFD modeling and thermal-hydraulic analysis for the passive decay heat removal of a sodium-cooled fast reactor

    Hung, T.C., E-mail: tchung@ntut.edu.t [Department of Mechanical Engineering, National Taipei University of Technology, 1, Sec. 3, Chung-hsiao E. Rd., Taipei 10608, Taiwan (China); Dhir, V.K. [Department of Mechanical and Aerospace Engineering, UCLA, CA (United States); Chang, J.C. [Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, Taiwan (China); Wang, S.K. [Department of Mechanical and Automation Engineering, I-Shou University, Taiwan (China)

    2011-01-15

    Research highlights: The COOLOD/N2 and PARET/ANL codes were used for a steady-state thermal-hydraulic and safety analysis of the 2 MW TRIGA MARK II reactor located at the Nuclear Studies Center of Maamora (CENM), Morocco. The main objective of this study is to ensure the safety margins of different safety related parameters by steady-state calculations at full power level (2 MW) The most important conclusion is that all obtained values of DNBR, fuel center and surface temperature, cladding surface temperature and coolant temperature across the hottest channel are largely far to compromise safety of the reactor. - Abstract: In this study, a pool-typed design similar to sodium-cooled fast reactor (SFR) of the fourth generation reactors has been modeled using CFD simulations to investigate the characteristics of a passive mechanism of Shutdown Heat Removal System (SHRS). The main aim is to refine the reactor pool design in terms of temperature safety margin of the sodium pool. Thus, an appropriate protection mechanism is maintained in order to ensure the safety and integrity of the reactor system during a shutdown mode without using any active heat removal system. The impacts on the pool temperature are evaluated based on the following considerations: (1) the aspect ratio of pool diameter to depth, (2) the values of thermal emissivity of the surface materials of reactor and guard vessels, and (3) innerpool liner and core periphery structures. The computational results show that an optimal pool design in geometry can reduce the maximum pool temperature down to {approx}551 {sup o}C which is substantially lower than {approx}627 {sup o}C as calculated for the reference case. It is also concluded that the passive Reactor Air Cooling System (RACS) is effective in removing decay heat after shutdown. Furthermore, thermal radiation from the surface of the reactor vessel is found to be important; and thus, the selection of the vessel surface materials with a high emissivity

  19. Evaluation of the heat-storage capability of shallow aquifers using active heat tracer tests and Fiber-Optics Distributed-Temperature-Sensing

    Suibert Oskar Seibertz, Klodwig; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2015-04-01

    In the course of the energy transition, geothermal energy storage and heat generation and cooling have proven to be environmental friendly alternatives to conventional energy. However, to ensure sustain usage, the heat transport behavior of aquifers and its distribution has to be studied. A tool to achieve this is the active heat tracer test, eg. Leaf et al. (2012). If active heat tracer tests are combined with in aquifer heat testing via electric heating-cables, eg. Liu et al. (2013), it is possible to observe heat transport and temperature signal decay without disturbing the original pressure field within the aquifer. In this field study a two channel High-Resolution-Fiber-Optic-Distributed-Temperature-Sensing and Pt100 were used to measure temperature signals within in two wells of 1.4 m distance, where the temperature difference was generated using a self regulating heating cable in the upstream well. High resolution Distributed-Temperature-Sensing measurements were achieved by coiling the fiber around screened plastic tubes. The upstream well was also used to observe heating (Δ Tmax approx. 24K) and temperature signal decay, while the downstream well was used to observe heat transport between both wells. The data was analyzed and compared to thermal conductivity of soil samples and Direct-Push (DP) Electrical-Conductivity-Logging and DP Hydraulic-Profiling results. The results show good agreement between DP data and temperature measurements proving the active heat tracer test is a suitable tool for providing reliable information on aquifer heat-storage capability. References Leaf, A.T., Hart, D.J., Bahr, J.M.: Active Thermal Tracer Tests for Improved Hydrostratigraphic Characterization. Ground Water, vol. 50, 2012 Liu, G., Knobbe, S., Butler, J.J.Jr.: Resolving centimeter-scale flows in aquifers and their hydrostratigraphic controls. Geophysical Research Letters, vol. 40, 2013

  20. Efficacy and Pertinence 01 Heat Treatments against Monilia Decay in Commerciai Condition

    Warlop, Franç,ois

    2002-01-01

    Post-harvest decay can lead to very important damages on stone fruits. especially in the Rhone valley. Hot water treatments are known to be efficient against many fruit pathogens including monilia, but industriai application remains difficult, since it can present some risks according to fruit maturity, thermostat accuracy of the engine We went on trying this alternative on peach decay, by testing a prototype lend by Xeda, in a professional station. Several parameters were to be eval...

  1. Preliminary Test Requirements for the Performance Test of Passive Decay Heat Removal System of Sodium-Cooled Fast Reactor

    In order to verify the concept of safety grade passive decay removal system PDRC (Passive Decay heat Removal Circuit) of KALIMER-600 and the design features to resolve the design issues for securing the cooling performance, the performance test is implemented. In this report, the preliminary test requirements for using as a guideline to the design of the experimental facility were established. Since the experimental facility should be designed so as to simulate the various thermal- hydraulic phenomena, as closely as possible, to be occurred in reference reactor during the decay heat removal operation, the design characteristics of the reference reactor (KALIMER-600) were analyzed for drawing major constitutive elements to be simulated in the facility. The preliminary test matrix was set up by the analysis of various design basis events and then the key test matrix was determined. Also, the priority for various thermal hydraulic phenomena which should be considered in the design of the experimental facility was determined by analyzing the phenomena for each key test matrix. Based on the analysis, the general design requirements for experimental facility were prepared and the design requirements for fluid systems and instrumentation were established. The test requirements in this report will be reflected in the scaling analysis and the basic design of the experimental facility. The test matrix specified in this report can be modified in the stage of main testing by considering the needs of experiments and circumstances at that time

  2. Decay heat removal by natural circulation in a 550-kW (electric) SP-100 power system for a lunar outpost

    In this paper, the natural-circulation decay heat removal capability of a 550-kW(electric) SP-100 reactor power system for a lunar outpost is investigated. A transient thermal-hydraulic model of the decay heat removal loop (DHRL) is developed to investigate the effects of the radiator surface area, the dimensions and elevation of the decay heat exchanger (DHE), and the diameter of the rise and down pipes on the passive decay heat removal of the system. The effect of gravity is also investigated in order to examine the applicability of earth-based test results to the actual system on the lunar surface. Results show that natural circulation of lithium coolant in the DHRL would keep the SP-100 reactor safely coolable after shutdown. However, the lithium coolant in the adiabatic rise pipe, directly downstream from the reactor core, could overheat by as much as 175 K above its nominal operation value of 1355 K at ∼ 200 s after shutdown. This coolant temperature increase can be reduced by as much as 50 K by increasing the height of the DHE duct to 15 cm; a further increase in the duct height would have little effect n the decay heat removal. Increasing the elevation of the DHE slightly improves the decay heat removal

  3. Studies on the characteristics of the separated heat pipe system with non-condensible gas for the use of the passive decay heat removal in reactor systems

    Experiments on the separated heat pipe system of variable conductance type, which enclose non-condensible gas, have been carried out with intention of applying such system to passive decay heat removal of the modular reactors such as HTR plant. Basic experiments have been carried out on the experimental apparatus consisting of evaporator, vapor transfer tube, condenser tube and return tube which returns the condensed liquid back to the evaporator. Water and methanol were examined as the working fluids and nitrogen gas was enclosed as the non-condensible gas. The behaviors of the system were examined for the parametric changes of the heat input under the various pressures of nitrogen gas initially enclosed, including the case without enclosing N2 gas for the comparison. The results of the experiments shows very clear features of self control characteristics. The self control mechanism was made clear, that is, in such system in which the condensing area in the condenser expands automatically in accordance with the increase of the heat input to keep the system temperature nearly constant. The working temperature of the system are clearly dependent on the pressure of the non-condensable gas initially enclosed, with higher system working temperature with higher initial gas pressure enclosed. The analyses were done on water and methanol as the working fluids, which show very good agreement with the experimental results. A lot of attractive applications are expected including the self switching feature with minimum heat loss during normal operation with maintaining the sufficient heat removal at accidents. (author)

  4. The AU-rich element mRNA decay-promoting activity of BRF1 is regulated by mitogen-activated protein kinase-activated protein kinase 2

    Maitra, Sushmit; Chou, Chu-Fang; Luber, Christian A.; Lee, Kyung-Yeol; Mann, Matthias; Chen, Ching-Yi

    2008-01-01

    Regulated mRNA decay is a highly important process for the tight control of gene expression. Inherently unstable mRNAs contain AU-rich elements (AREs) in the 3′ untranslated regions that direct rapid mRNA decay by interaction with decay-promoting ARE-binding proteins (ARE-BPs). The decay of ARE-containing mRNAs is regulated by signaling pathways that are believed to directly target ARE-BPs. Here, we show that BRF1 involved in ARE-mediated mRNA decay (AMD) is phosphorylated by MAPK-activated p...

  5. Sodium experiment on fully natural circulation systems for decay heat removal in Japan sodium-cooled fast reactor

    Fully natural circulation system is adopted in a decay heat removal system (DHRS) of Japan Sodium Cooled Fast Reactor (JSFR). The DHRS of JSFR consists of one unit of DRACS (direct reactor auxiliary cooling system), which has a dipped heat exchanger in the reactor vessel and two units of PRACS, which has a heat exchanger in a primary-side inlet plenum of IHX in each loop. Sodium experiments were carried out for heat transfer characteristics of a sodium-sodium heat exchanger of PRACS and start-up transient of the DHRS loop with parameters of pressure loss coefficients in the loops. The transient experiments for the start-up of DHRS loop showed that quick increase of natural draft in the air duct followed by smooth increase of sodium flow rate in the DHRS loop. Influences of the pressure loss coefficients in the primary loop and the DHRS loop were limited on the core temperature and also heat removal of PRACS, respectively due to recovery of natural circulation head via the increase of temperature difference in each loop. (author)

  6. Experimental evaluation of decrease in the activities of polyphosphate/glycogen-accumulating organisms due to cell death and activity decay in activated sludge.

    Hao, Xiaodi; Wang, Qilin; Cao, Yali; van Loosdrecht, Mark C M

    2010-06-15

    Decrease in bacterial activity (biomass decay) in activated sludge can result from cell death (reduction in the amount of active bacteria) and activity decay (reduction in the specific activity of active bacteria). The goal of this study was to experimentally differentiate between cell death and activity decay as the cause of decrease in bacterial activity. By means of measuring maximal anaerobic phosphate release rates, verifying membrane integrity by live/dead staining and verifying presence of 16S rRNA with fluorescence in situ hybridization (FISH), the decay rates and death rates of polyphosphate-accumulating organisms (PAOs) in a biological nutrient removal (BNR) system and a laboratory phosphate removing sequencing batch reactor (SBR) system were determined, respectively, under famine conditions. In addition, the decay rate and death rate of glycogen-accumulating organisms (GAOs) in a SBR system with an enrichment culture of GAOs were also measured under famine conditions. Hereto the maximal anaerobic volatile fatty acid uptake rates, live/dead staining, and FISH were used. The experiments revealed that in the BNR and enriched PAO-SBR systems, activity decay contributed 58% and 80% to the decreased activities of PAOs, and that cell death was responsible for 42% and 20% of decreases in their respective activities. In the enriched GAOs system, activity decay constituted a proportion of 74% of the decreased activity of GAOs, and cell death only accounted for 26% of the decrease of their activity. PMID:20178124

  7. A model for the analysis of loss of decay heat removal accident in MTR pool type research reactors

    During a loss of coolant accident leading to total emptying of the reactor pool, the decay heat could be removed through air natural convection. However, under partial pool emptying the core is partially submerged and the coolant circulation inside the fuel element could no more be possible. In such conditions, a core overheat take place, and the heat is essentially diffused from the core to its periphery by combined thermal radiation and conduction. In order to predict fuel element temperature evolution under such conditions a mathematical model is performed. The model is based on a three dimensional geometry and takes into account a variety of core configurations including fuel elements (standard and control), reflector elements and grid plates. The homogeneous flow model is used and the time and space dependent non-linear partial differential fluid conservation equations are solved using a semi-implicit finite difference method. Preliminary tests of the developed model were made by considering a series of hypothetical accidents. In the current framework a loss of decay heat removal accidents in the IAEA benchmark open pool MTR-type research reactor is considered. It is shown that in the case of a low core immersion height no water boiling is observed and the fuel surface temperature rise remains below the melting point of the aluminium cladding. (author)

  8. Development and testing of heat transport fluids for use in active solar heating and cooling systems

    Parker, J. C.

    1981-01-01

    Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed.

  9. Neutronic characterization and decay heat calculations in the in-vessel fuel storage facilities for MYRRHA/FASTEF

    Highlights: ► Monte Carlo design of reactor facilities. ► Neutron coupling assessment between critical core and fresh fuel in the storage vessels. ► Power contribution by induced fission from neutrons leaving the core, spontaneous fission and (α, n) sources. ► Power decay heat estimation for different reactor fuel cycles scenarios. ► Material damage assessment in the storage vessels. - Abstract: The main objective of the Central Design Team (CDT) project is to establish an engineering design of a Fast Spectrum Transmutation Experimental Facility (FASTEF) that is the pilot plant of an experimental-scale of both an Accelerator Driven System (ADS) and a Lead Fast Reactor (LFR), based on the MYRRHA reactor concept, planned to be built during the next decade. The MYRRHA reactor concept is devoted to be a multi-purpose irradiation facility aimed at demonstrating the efficient transmutation of long-lived and high radiotoxicity minor actinides, fission products and the associated technology. An important issue regarding the reactor design of the MYRRHA/FASTEF experiment is the In-Vessel Fuel Storage Facilities (IVFSFs), both for fresh and spent fuel, as it might have an impact on the criticality of the overall system that must be quantified. In this work, the neutronic analysis of the in-vessel fuel storage facility and its coupling with the critical core was performed, using the state of the art Monte Carlo program MCNPX 2.6.0 and ORIGEN 2.2 computer code system for calculating the buildup and decay heat of spent fuel. Several parameters were analyzed, like the criticality behavior (namely the Keff), the neutron fluxes and their variations, the fission power production and the radiation damage (the displacements per atom). Finally, also the heat power generated by the fission products decay in the spent fuel was assessed.

  10. Preliminary design activities for solar heating and cooling systems

    1978-01-01

    Information on the development of solar heating and cooling systems is presented. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities.

  11. Development of margin assessment methodology of decay heat removal function against external hazards. (1) Project overview and snow PRA methodology

    This paper describes mainly snow probabilistic risk assessment (PRA) methodology development in addition to the project overview. This project addresses extreme weathers (snow, tornado, wind and rainfall), volcanic phenomena and forest fire as representative external hazards. In this project, the methodologies of both PRA and margin assessment are developed for each external hazard through external hazard and accident sequence evaluations mainly in terms of decay heat removal function of a sodium-cooled fast reactor (SFR). Using recent 50 year weather data at a typical Japanese SFR site, snow hazard categories were set the combination of daily snowfall depth (snowfall speed) and snowfall duration which can be calculated by dividing the snow depth by the snowfall speed. For each snow hazard category, the accident sequence was evaluated by producing event trees which consist of several headings representing the loss of decay heat removal. Snow removal action and manual operation of the air cooler dampers were introduced into the event tree as accident managements. In this paper, the snow PRA showed less than 10-6/reactor-year of core damage frequency. The dominant snow hazard category was the combination of 1−2 m/day of snowfall speed and 0.5−0.75 day of snowfall duration. Importance and sensitivity analyses indicated a high risk contribution to secure the access routes. (author)

  12. ANITA-2000 activation code package - updating of the decay data libraries and validation on the experimental data of the 14 MeV Frascati Neutron Generator

    Frisoni Manuela

    2016-01-01

    Full Text Available ANITA-2000 is a code package for the activation characterization of materials exposed to neutron irradiation released by ENEA to OECD-NEADB and ORNL-RSICC. The main component of the package is the activation code ANITA-4M that computes the radioactive inventory of a material exposed to neutron irradiation. The code requires the decay data library (file fl1 containing the quantities describing the decay properties of the unstable nuclides and the library (file fl2 containing the gamma ray spectra emitted by the radioactive nuclei. The fl1 and fl2 files of the ANITA-2000 code package, originally based on the evaluated nuclear data library FENDL/D-2.0, were recently updated on the basis of the JEFF-3.1.1 Radioactive Decay Data Library. This paper presents the results of the validation of the new fl1 decay data library through the comparison of the ANITA-4M calculated values with the measured electron and photon decay heats and activities of fusion material samples irradiated at the 14 MeV Frascati Neutron Generator (FNG of the NEA-Frascati Research Centre. Twelve material samples were considered, namely: Mo, Cu, Hf, Mg, Ni, Cd, Sn, Re, Ti, W, Ag and Al. The ratios between calculated and experimental values (C/E are shown and discussed in this paper.

  13. Uncertainty evaluation of reliability of safety grade decay heat removal system of Indian prototype fast breeder reactor

    Highlights: • Uncertainty analysis of failure frequency of SGDHRS of a medium sized fast reactor is studied. • Lognormal distribution of failure rate of components is taken with error factor of 3. • The error factor in the distribution of failure frequency in most cases is 3. • The relative importance of the safety components is brought out. - Abstract: Deterministic and probabilistic safety assessment of nuclear power reactor technology is very important in assuring that the design is robust and safety systems perform as per requirement. The parameters required as input data for such analysis have uncertainties associated with them. Their impact is to be assessed on the results obtained for such analyses and it affects the overall decision making process. Safety Grade Decay Heat Removal System (SGDHRS) is one of the safety systems in fast breeder reactors and itremoves decay heat after reactor shutdown. It is a critical safety system; hence failure frequency for SGDHR is targeted to be less than 1.0 × 10−7 per reactor year. By bringing diversity in some of the components of SGDHRS, such as sodium-to-sodium decay heat exchanger (DHX), sodium to air heat exchanger (AHX) and valves, one can achieve the targeted low failure frequency of SGDHRS. We perform uncertainty analysis of the reliability of such SGDHRS here. Uncertainty in failure rate (of components of SGDHRS) is assumed to follow the log-normal distribution with error factor of three. Monte Carlo method of sampling is used in MATLAB environment. Results are obtained in terms of mean, median and standard deviation values of failure frequency. Percentile and confidence interval analysis of mean values are also obtained. These provide 95 and 98 percentile and confidence interval values of 98%, 99% and 99.8%. It is found that error factor of failure frequency of SGDHRS is found to be less than 3 in all the cases except the one in which DHX, AHX and Valves are designed with diversity in design. It is to

  14. Reduced-scale water test of natural circulation for decay heat removal in loop-type sodium-cooled fast reactor

    Highlights: • The natural circulation characteristics of a loop-type SFR are examined by a water test. • The performance of decay heat removal system is evaluated using a similarity law. • The effects of flow deviation in the parallel piping of a primary loop are clarified. • The reproducibility of the natural circulation test is confirmed. - Abstract: Water tests of a loop-type sodium-cooled fast reactor have been conducted to physically evaluate the natural circulation characteristics. The water test apparatus was manufactured as a 1/10-scale mock-up of the Japan Sodium-Cooled Fast Reactor, which adopts a decay heat removal system (DHRS) utilizing natural circulation. Tests simulating a variety of events and operation conditions clarified the thermal hydraulic characteristics and core-cooling performance of the natural circulation in the primary loop. Operation conditions such as the duration of the pump flow coast-down and the activation time of the DHRS affect the natural circulation characteristics. A long pump flow coast-down cools the upper plenum of the reactor vessel (RV). This causes the loss of the buoyant force in the RV. The test result indicates that a long pump flow coast-down tends to result in a rapid increase in the core temperature because of the loss of the buoyant force. The delayed activation of the DHRS causes a decrease in the natural circulation flow rate and a temperature rise in the RV. Flow rate deviation and a reverse flow appear in the parallel cold-leg piping in some events, which cause thermal stratification in the cold-leg piping. The DHRS prevents the core temperature from fatally rise even for the most severe design-basis event, in which sodium leakage in a secondary loop of the DHRS and the opening failure of a single damper of the air cooler occur simultaneously. In the water test for the case of siphon break in the primary loop, which is one of the design extension conditions, a circulation flow consisting of ascendant

  15. Heat dissipation guides activation in signaling proteins.

    Weber, Jeffrey K; Shukla, Diwakar; Pande, Vijay S

    2015-08-18

    Life is fundamentally a nonequilibrium phenomenon. At the expense of dissipated energy, living things perform irreversible processes that allow them to propagate and reproduce. Within cells, evolution has designed nanoscale machines to do meaningful work with energy harnessed from a continuous flux of heat and particles. As dictated by the Second Law of Thermodynamics and its fluctuation theorem corollaries, irreversibility in nonequilibrium processes can be quantified in terms of how much entropy such dynamics produce. In this work, we seek to address a fundamental question linking biology and nonequilibrium physics: can the evolved dissipative pathways that facilitate biomolecular function be identified by their extent of entropy production in general relaxation processes? We here synthesize massive molecular dynamics simulations, Markov state models (MSMs), and nonequilibrium statistical mechanical theory to probe dissipation in two key classes of signaling proteins: kinases and G-protein-coupled receptors (GPCRs). Applying machinery from large deviation theory, we use MSMs constructed from protein simulations to generate dynamics conforming to positive levels of entropy production. We note the emergence of an array of peaks in the dynamical response (transient analogs of phase transitions) that draw the proteins between distinct levels of dissipation, and we see that the binding of ATP and agonist molecules modifies the observed dissipative landscapes. Overall, we find that dissipation is tightly coupled to activation in these signaling systems: dominant entropy-producing trajectories become localized near important barriers along known biological activation pathways. We go on to classify an array of equilibrium and nonequilibrium molecular switches that harmonize to promote functional dynamics. PMID:26240354

  16. Conceptual study of ferromagnetic pebbles for heat exhaust in fusion reactors with short power decay length

    N. Gierse

    2015-03-01

    The key results of this study are that very high heat fluxes are accessible in the operation space of ferromagnetic pebbles, that ferromagnetic pebbles are compatible with tokamak operation and current divertor designs, that the heat removal capability of ferromagnetic pebbles increases as λq decreases and, finally, that for fusion relevant values of q∥ pebble diameters below 100 μm are required.

  17. Consideration on rationalization of reactor safety systems. Reliability assessment of decay heat removal systems in commercialized sodium cooled FBR concepts

    For commercialization of FBR (Fast Breeder Reactor), the reactor safety systems are needed not only to have necessary and enough reliability but also to decrease the amount of materials in order that the FBR has economical competitiveness against LWR (Light Water Reactor) and another electrical power supply systems. In this study, reliability assessment, which calculates the occurrence frequencies of PLOHS (Protected Loss Of Heat Sink) sequences, was performed for three kinds of large size sodium cooled fast reactors with decreased number of loops and of support systems examined in the Feasibility Studies on Commercialized FBR System. The realistic evaluation was performed using the failure rate data of components based on the domestic LWR operating experience. The result is: All of the three kinds of commercialized FBR concepts are expected to achieve the frequencies of PLOHS sequences caused by internal events of the plant under 10-6/ry, assuming that common-mode-failure is excluded. In addition, the dominating cause of the coincidence of the incidents and the information that improves reliability of decay heat removal systems are summarized for each concept. In order to evaluate design margin, the reliability assessment was performed in the case that the capacity of natural circulation cooling was rein forced from 100%/3 x 3 loops to 50% x 3 loops or from 25% x 4 loops to 100%/3 x 4 loops easing to succeed decay heat removal. In that case, it is confirmed that the frequencies of PLOHS sequences decrease by about one order of magnitude. (author)

  18. Actinide, Activation Product and Fission Product Decay Data for Reactor-based Applications

    The UK Activation Product Decay Data Library was first released in September 1977 as UK-PADD1, to be followed by regular improvements on an almost yearly basis up to the assembly of UKPADD6.12 in March 2013. Similarly, the UK Heavy Element and Actinide Decay Data Library followed in December 1981 as UKHEDD1, with the implementation of various modifications leading to UKHEDD2.6, February 2008. Both the data content and evaluation procedures are defined, and the most recent evaluations are described in terms of specific radionuclides and the resulting consistency of their recommended decay-data files. New versions of the UKPADD and UKHEDD libraries are regularly submitted to the NEA Data Bank for possible inclusion in the JEFF library

  19. Analysis of removal of residual decay heat from interim storage facilities by means of the CFD program FLUENT

    Within the scope of nuclear licensing procedures of on-site interim storage facilities for dual purpose casks it is necessary, among other things, to provide proof of sufficient removal of the residual decay heat emitted by the casks. The results of the analyses performed for this purpose define e.g. the boundary conditions for further thermal analyses regarding the permissible cask component temperatures or the maximum permissible temperatures of the fuel cladding tubes of the fuel elements stored in the casks. Up to now, for the centralized interim storage facilities in Germany such analyses were performed on the basis of experimental investigations using scaled-down storage geometries. In the engineering phase of the Lingen on-site interim storage facility, proof was furnished for the first time using the CFD (computational fluid dynamics) program FLUENT. The program FLUENT is an internationally recognized and comprehensively verified program for the calculation of flow and heat transport processes. Starting from a brief discussion of modeling and the different boundary conditions of the computation, this contribution presents various results regarding the temperatures of air, cask surfaces and storage facility components, the mass flows through the storage facility and the heat transfer at the cask surface. The interface point to the cask-specific analyses is defined to be the cask surface

  20. Implementación del modelo de decay heat ANSI/ ANS-5.1-2005 EN TRAC-BF1

    SOLER MARTÍNEZ, MARÍA DESAMPARADOS; Barrachina Celda, Teresa María; Miró Herrero, Rafael; Concejal, A.; Melara, J.; Verdú Martín, Gumersindo Jesús

    2012-01-01

    En este artículo se muestran los resultados de la implementación del modelo de calor residual (Decay Heat) ANSI/ANS-5.1 2005 en el código termohidráulico TRAC-BF1. Los modelos para el cálculo del calor residual en el código TRAC-BF1 se corresponden con el estándar ANS 1973, por defecto, y con el estándar ANS 1979, si es seleccionado por parte del usuario. Con la entrada en vigor del estándar ANS 1994 y, su posterior revisión, el estándar ANS 2005 los modelos que presenta TRAC-...

  1. Comparison of deterministic and stochastic approaches for isotopic concentration and decay heat uncertainty quantification on elementary fission pulse

    Lahaye S.

    2016-01-01

    Full Text Available Uncertainty quantification of interest outputs in nuclear fuel cycle is an important issue for nuclear safety, from nuclear facilities to long term deposits. Most of those outputs are functions of the isotopic vector density which is estimated by fuel cycle codes, such as DARWIN/PEPIN2, MENDEL, ORIGEN or FISPACT. CEA code systems DARWIN/PEPIN2 and MENDEL propagate by two different methods the uncertainty from nuclear data inputs to isotopic concentrations and decay heat. This paper shows comparisons between those two codes on a Uranium-235 thermal fission pulse. Effects of nuclear data evaluation’s choice (ENDF/B-VII.1, JEFF-3.1.1 and JENDL-2011 is inspected in this paper. All results show good agreement between both codes and methods, ensuring the reliability of both approaches for a given evaluation.

  2. Comparison of deterministic and stochastic approaches for isotopic concentration and decay heat uncertainty quantification on elementary fission pulse

    Lahaye, S.; Huynh, T. D.; Tsilanizara, A.

    2016-03-01

    Uncertainty quantification of interest outputs in nuclear fuel cycle is an important issue for nuclear safety, from nuclear facilities to long term deposits. Most of those outputs are functions of the isotopic vector density which is estimated by fuel cycle codes, such as DARWIN/PEPIN2, MENDEL, ORIGEN or FISPACT. CEA code systems DARWIN/PEPIN2 and MENDEL propagate by two different methods the uncertainty from nuclear data inputs to isotopic concentrations and decay heat. This paper shows comparisons between those two codes on a Uranium-235 thermal fission pulse. Effects of nuclear data evaluation's choice (ENDF/B-VII.1, JEFF-3.1.1 and JENDL-2011) is inspected in this paper. All results show good agreement between both codes and methods, ensuring the reliability of both approaches for a given evaluation.

  3. Analytical solution for laser evaporative heating process: time exponentially decaying pulse case

    The modelling of the laser heating process gives insight into the laser workpiece interaction and minimizes the experimental cost. In the present study, analytical solution for the laser pulse heating process is considered and the closed form solution for the temperature rise due to time exponentially varying pulse is obtained. In the analysis, evaporation of the surface is taken into account. A Laplace transformation method was used when formulating the closed form solution for the temperature profiles. The effect of pulse parameters on the temperature profiles is examined in detail. It is found that the closed form solution derived from the present study reduces to the previously obtained analytical solution when the surface recession velocity is set to zero in the closed form solution. Moreover, the predictions of numerical simulation and closed form solution are found to be in good agreement. (author)

  4. Basic CFD investigation of decay heat removal in a pool type research reactor

    Safety is one of the most important and desirable characteristic in a nuclear plant. Natural circulation cooling systems are noted for providing passive safety. These systems can be used as mechanism for removing the residual heat from the reactor, or even as the main cooling system for heated sections, such as the core. In this work, a computational fluid-dynamics (CFD) code is used to simulate the process of natural circulation in an open pool research reactor after its shutdown. The physical model studied is similar to the Open Pool Australian Light water reactor (OPAL), and contains the core, cooling pool, reflecting tank, circulation pipes and chimney. For best computing performance, the core region was modeled as a porous media, where the parameters were obtained from a separately detailed CFD analysis. (author)

  5. Plasma heating in the very early and decay phases of solar flares

    Falewicz, R.; Siarkowski, M.; Rudawy, P.

    2011-01-01

    In this paper we analyze the energy budgets of two single-loop solar flares under the assumption that non-thermal electrons are the only source of plasma heating during all phases of both events. The flares were observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary Operational Environmental Satellite (GOES) on September 20, 2002 and March 17, 2002, respectively. For both investigated flares we derived the energy fluxes contained in non-thermal electron beams...

  6. Evaluation of the Safety Issue Concerning the Potential for Loss of Decay Heat Removal Function due to Crude Oil Spill in the Ultimate Heat Sink of Nuclear Reactors

    A barge crashed into a moored oil tanker at about 7:15 a.m., Dec. 12, 2007, dumping around 10,500 tons of crude oil into the sea in Korea. The incident took place about 15 kilometers northwest of Manripo beach in South Chungcheong where is Korea's west coast in the Yellow Sea. In a few days, the oil slicks spread to the northern and southern tips of the Taean Peninsula by strong winds and tides. As time went the spilled oil floating on the surface of sea water was volatilized to become tar-balls and lumps and drifted far away in the southern direction. 13 days after the incident, some of oil slicks and tar lumps were observed to flow in the service water intake at the Younggwang nuclear power plants (NPPs) operating 6 reactors, which are over 150 km away from the incident spot in the southeastern direction. According to the report by the Younggwang NPPs, a total weight 83 kg of tar lumps was removed for about 3 days. Oil spills in the sea can happen in any country or anytime due to human errors or mistakes, wars, terrors, intentional dumping of waste oils, and natural disasters like typhoon and tsunami. In fact, there have been 7 major oil spills over 10,000 tons that have occurred around the world since 1983. As such serious oil spill incidents may happen near the operating power plants using the sea water as ultimate heat sink. To ensure the safe operation of nuclear reactors it is required to evaluate the potential for loss of decay heat removal function of nuclear reactors due to the spilled oils flowing in the service water intake, from which the service water is pumped. Thus, Korea Institute of Nuclear Safety identified this problem as one of the important safety. When an incident of crude oil spill from an oil carrier occurs in the sea near the nuclear power plants, the spilled oil can be transported to the intake pit, where all service water pumps locate, by sea current and wind drift (induced) current. The essential service water pumps take the service

  7. Active heat exchange system development for latent heat thermal energy storage

    Lefrois, R.T.; Knowles, G.R.; Mathur, A.K.; Budimir, J.

    1979-02-01

    The report describes active heat exchange concepts for use with thermal energy storage systems in the temperature range of 250/sup 0/C to 350/sup 0/C, using the heat of fusion of molten salts for storing thermal energy. It identifies over 25 novel techniques for active heat exchange thermal energy storage systems. Salt mixtures that freeze and melt in appropriate ranges are identified and are evaluated for physico-chemical, economic, corrosive and safety characteristics. Eight active heat exchange concepts for heat transfer during solidification are conceived and conceptually designed for use with selected storage media. The concepts are analyzed for their scalability, maintenance, safety, technological development and costs. A model for estimating and scaling storage system costs is developed and is used for economic evaluation of salt mixtures and heat exchange concepts for a large scale application. The importance of comparing salts and heat exchange concepts on a total system cost basis, rather than the component cost basis alone, is pointed out. Comparison of these costs with current state-of-the-art systems should be avoided due to significant differences in developmental status. The heat exchange concepts were sized and compared for 6.5 MPa/281/sup 0/C steam conditions and a 1000 MW(t) heat rate for six hours. A cost sensitivity analysis for other design conditions is also carried out. The study resulted in the selection of a shell and coated-tube heat exchanger concept and a direct contact-reflux boiler heat exchange concept. For the storage medium, a dilute eutectic mixture of 99 wt % NaNO/sub 3/ and 1 wt % NaOH is selected for use in experimenting with the selected heat exchanger concepts in subsequent tasks.

  8. Heat dissipation guides activation in signaling proteins

    Weber, Jeffrey K.; Shukla, Diwakar; Pande, Vijay S.

    2015-01-01

    As with their macroscopic counterparts, the moving parts of nanoscale protein machines grow hot while in operation. A portion of the energy biomolecules harness to perform meaningful work is always dissipated as heat into the surroundings. Here, we feature a methodology by which dominant dissipative trajectories can be extracted from detailed models of protein dynamics. In two important classes of signaling proteins [kinases and G-protein–coupled receptors (GPCRs)], we find that the regions o...

  9. Periphytic photosynthetic stimulation of extracellular enzyme activity in aquatic microbial communities associated with decaying typha litter.

    Francoeur, Steven N; Schaecher, Mark; Neely, Robert K; Kuehn, Kevin A

    2006-11-01

    We examined the effect of light on extracellular enzyme activities of periphytic/endogenous microbial assemblages associated with decomposing litter of an emergent macrophyte Typha angustifolia within a small inland wetland in southeastern Michigan. Standing-dead Typha leaf litter was collected, placed into floating wire mesh litter baskets, and submerged in a wetland pool. Enzyme saturation assays were conducted on three occasions following litter submergence (days 9, 28, and 44) to generate saturation curves for the individual enzymes tested and to examine potential differences in enzyme saturation kinetics during microbial colonization and development. Experimental light manipulations were conducted on two occasions during microbial development (days 10 and 29). Short-term (30 min) light exposure significantly increased extracellular beta-glucosidase activity of litter-associated microbial communities. Activities of beta-xylosidase and leucine-aminopeptidase were not stimulated, and stimulation of phosphatase activity was variable. The exact mechanism for increased enzyme activity remains unknown, but it may have been increased pH arising from periphytic algal photosynthesis. These results suggest that extracellular enzyme activity in microbial communities colonizing natural organic substrata may be influenced by light/photosynthesis, as has previously been demonstrated for periphyton communities grown on artificial, inert substrata. Thus, light/photosynthetic mediated stimulation of extracellular enzyme activities may be a common occurrence in microbial communities associated with natural decaying plant litter in wetlands and might engender diurnal patterns in other microbial decay processes (e.g., production, organic matter decomposition, and mineralization). PMID:17082997

  10. 多样化非能动衰变热排出方法研究%Study on diverse passive decay heat removal approach

    林千; 司胜义

    2012-01-01

    One of the most important principles for nuclear safety is the decay heat removal in accidents. Passive decay heat removal systems are extremely helpful to enhance the safety. In currently design of many advanced nuclear reactors, kinds of passive systems are proposed or developed, such as the passive residual heat removal system, passive injection system, passive containment cooling system. These systems provide entire passive heat removal paths from core to ultimate heat sink. Various kinds of passive systems for decay heat removal are summarized; their common features or differences on heat removal paths and design principle are analyzed. It is found that, these passive decay heat removal paths are similarly common on and connected by several basic heat transfer modes and steps. By the combinations or connections of basic modes and steps, new passive decay heat removal approach or diverse system can be proposed.%事故情况下的衰变热排出是涉及核安全的重要方面.采用非能动方法来排出衰变热对于提高核反应堆的安全性非常有益.在目前一些先进反应堆中通过设置非能动余热排出系统、非能动安注系统、非能动安全壳冷却系统等安全子系统,形成多样化的从堆芯到最终热阱的非能动衰变热排出渠道.论文对多种非能动衰变热排出方法和系统设计方案进行了归纳总结,比较分析了这些非能动衰变热排出方法的共性特征和区别,探讨了非能动衰变热排出系统的设计原理.通过对传热过程分解,将这些衰变热排出方法表达为一些基本传热形式的不同组合方式,根据不同的组合可获得多样化的非能动衰变热排出方法和新的系统设计方案.

  11. Oxidative Activity of Heated Coal Affected by Antypirogens

    Torosyan, V. F.; Torosyan, E. S.; Borovikov, I. F.; Yakutova, V. A.

    2016-04-01

    The effect of antypirogens on chemical activity of heated coal is studied. It is proved that ammonium sulfate, calcium phosphate, calcium chloride, calcium nitrate and acid fluoride are the most effective antypirogens.

  12. Balloons and Bottles: Activities on Air-Sea Heat Exchange.

    Murphree, Tom

    1998-01-01

    Presents an activity designed to demonstrate how heating and cooling an air mass affects its temperature, volume, density, and pressure. Illustrates how thermal energy can cause atmospheric motion such as expansion, contraction, and winds. (Author/WRM)

  13. Heat of Hydration of Low Activity Cementitious Waste Forms

    Nasol, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-23

    During the curing of secondary waste grout, the hydraulic materials in the dry mix react exothermally with the water in the secondary low-activity waste (LAW). The heat released, called the heat of hydration, can be measured using a TAM Air Isothermal Calorimeter. By holding temperature constant in the instrument, the heat of hydration during the curing process can be determined. This will provide information that can be used in the design of a waste solidification facility. At the Savannah River National Laboratory (SRNL), the heat of hydration and other physical properties are being collected on grout prepared using three simulants of liquid secondary waste generated at the Hanford Site. From this study it was found that both the simulant and dry mix each had an effect on the heat of hydration. It was also concluded that the higher the cement content in the dry materials mix, the greater the heat of hydration during the curing of grout.

  14. Radon decay products in realistic living rooms and their activity distributions in human respiratory system

    In this study, the individual activity concentrations of attached short-lived radon decay products (218Po, 214Pb and 214Po) in aerosol particles were measured in ten poorly ventilated realistic living rooms. Using standard methodologies, the samples were collected using a filter holder technique connected with alpha-spectrometric. The mean value of air activity concentration of these radionuclides was found to be 5.3±0.8, 4.5±0.5 and 3.9±0.4 Bq m-3, respectively. Based on the physical properties of the attached decay products and physiological parameters of light work activity for an adult human male recommended by ICRP 66 and considering the parameters of activity size distribution (AMD = 0.25 μm and σg = 2.5) given by NRC, the total and regional deposition fractions in each airway generation could be evaluated. Moreover, the total and regional equivalent doses in the human respiratory tract could be estimated. In addition, the surface activity distribution per generation is calculated for the bronchial region (BB) and the bronchiolar region (bb) of the respiratory system. The maximum values of these activities were found in the upper bronchial airway generations. (authors)

  15. Active latent heat storage with a screw heat exchanger - experimental results for heat transfer and concept for high pressure steam

    Zipf, Verena; Willert, Daniel; Neuhäuser, Anton

    2016-05-01

    An innovative active latent heat storage concept was invented and developed at Fraunhofer ISE. It uses a screw heat exchanger (SHE) for the phase change during the transport of a phase change material (PCM) from a cold to a hot tank or vice versa. This separates heat transfer and storage tank in comparison to existing concepts. A test rig has been built in order to investigate the heat transfer coefficients of the SHE during melting and crystallization of the PCM. The knowledge of these characteristics is crucial in order to assess the performance of the latent heat storage in a thermal system. The test rig contains a double shafted SHE, which is heated or cooled with thermal oil. The overall heat transfer coefficient U and the convective heat transfer coefficient on the PCM side hPCM both for charging and discharging have been calculated based on the measured data. For charging, the overall heat transfer coefficient in the tested SHE was Uch = 308 W/m2K and for discharging Udis = 210 W/m2K. Based on the values for hPCM the overall heat transfer coefficients for a larger SHE with steam as heat transfer fluid and an optimized geometry were calculated with Uch = 320 W/m2K for charging and Udis = 243 W/m2K for discharging. For pressures as high as p = 100 bar, an SHE concept has been developed, which uses an organic fluid inside the flight of the SHE as working media. With this concept, the SHE can also be deployed for very high pressure, e.g. as storage in solar thermal power plants.

  16. Active heat exchange system development for latent heat thermal energy storage

    Lefrois, R. T.; Knowles, G. R.; Mathur, A. K.; Budimir, J.

    1979-01-01

    Active heat exchange concepts for use with thermal energy storage systems in the temperature range of 250 C to 350 C, using the heat of fusion of molten salts for storing thermal energy are described. Salt mixtures that freeze and melt in appropriate ranges are identified and are evaluated for physico-chemical, economic, corrosive and safety characteristics. Eight active heat exchange concepts for heat transfer during solidification are conceived and conceptually designed for use with selected storage media. The concepts are analyzed for their scalability, maintenance, safety, technological development and costs. A model for estimating and scaling storage system costs is developed and is used for economic evaluation of salt mixtures and heat exchange concepts for a large scale application. The importance of comparing salts and heat exchange concepts on a total system cost basis, rather than the component cost basis alone, is pointed out. The heat exchange concepts were sized and compared for 6.5 MPa/281 C steam conditions and a 1000 MW(t) heat rate for six hours. A cost sensitivity analysis for other design conditions is also carried out.

  17. Decay heat measurement of 235U in the time period from 10 to 1000 seconds

    Nearly all components of the experimental facility were completed. The automatic control of the pneumatic transfer system and the active fuel sample handling mechanism was constructed and succesfully tested. The computer programs for the calorimeter control and data recording by a 8K-minicomputer were provided and the measuring electronics completed. The shielding from γ- and delayed neutron radiation was designed and constructed and the security report for the operation of the facility at the reactor written. (orig./RW)

  18. A portable backup power supply to assure extended decay heat removal during natural phenomena-induced station blackout

    The High Flux Isotope Reactor (HFIR) is a light water cooled and moderated flux-trap type research reactor located at Oak Ridge National Laboratory (ORNL). Coolant circulation following reactor shutdown is provided by the primary coolant pumps. DC-powered pony motors drive these pumps at a reduced flow rate following shutdown of the normal ac-powered motors. Forced circulation decay heat removal is required for several hours to preclude core damage following shutdown. Recent analyses identified a potential vulnerability due to a natural phenomena-induced station blackout. Neither the offsire power supply nor the onsite emergency diesel generators are designed to withstand the effects of seismic events or tornadoes. It could not be assured that the capacity of the dedicated batteries provided as a backup power supply for the primary coolant pump pony motors is adequate to provide forced circulation cooling for the required time following such events. A portable backup power supply added to the plant to address this potential vulnerability is described

  19. Development of an evaluation methodology for the natural circulation decay heat removal system in a sodium cooled fast reactor

    A natural circulation evaluation methodology has been developed to ensure the safety of a sodium-cooled fast reactor (SFR) of 1500 MW adopting the natural circulation decay heat removal system (NC-DHRS). The methodology consists of a one-dimensional safety analysis which can evaluate the core hot spot temperature taking into account the temperature flattening effect in the core, a three-dimensional fluid flow analysis which can evaluate the thermal-hydraulics for local convections and thermal stratifications in the primary system and DHRS, and a statistical safety evaluation method for the hot spot temperature in the core. The safety analysis method and the three-dimensional analysis method have been validated using results of a 1/10 scaled water test simulating the primary system of the SFR and a sodium test simulating a part of the primary system and the DHRS with about a 1/7 scale, and the applicability of the safety analysis for the SFR has been confirmed by comparing with the three-dimensional analysis adopting the turbulence model. Finally, a statistical safety evaluation has been performed for the SFR using the safety analysis method. (author)

  20. Numerical simulations of active region scale flux emergence: From spot formation to decay

    Rempel, M. [High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307 (United States); Cheung, M. C. M., E-mail: rempel@ucar.edu [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover St, Palo Alto, CA 94304 (United States)

    2014-04-20

    We present numerical simulations of active region scale flux emergence covering a time span of up to 6 days. Flux emergence is driven by a bottom boundary condition that advects a semi-torus of magnetic field with 1.7 × 10{sup 22} Mx flux into the computational domain. The simulations show that, even in the absence of twist, the magnetic flux is able the rise through the upper 15.5 Mm of the convection zone and emerge into the photosphere to form spots. We find that spot formation is sensitive to the persistence of upflows at the bottom boundary footpoints, i.e., a continuing upflow would prevent spot formation. In addition, the presence of a torus-aligned flow (such flow into the retrograde direction is expected from angular momentum conservation during the rise of flux ropes through the convection zone) leads to a significant asymmetry between the pair of spots, with the spot corresponding to the leading spot on the Sun being more axisymmetric and coherent, but also forming with a delay relative to the following spot. The spot formation phase transitions directly into a decay phase. Subsurface flows fragment the magnetic field and lead to intrusions of almost field free plasma underneath the photosphere. When such intrusions reach photospheric layers, the spot fragments. The timescale for spot decay is comparable to the longest convective timescales present in the simulation domain. We find that the dispersal of flux from a simulated spot in the first two days of the decay phase is consistent with self-similar decay by turbulent diffusion.

  1. Simulation of decay heat removal by natural convection in a pool type fast reactor model-ramona-with coupled 1D/2D thermal hydraulic code system

    Kasinathan, N.; Rajakumar, A.; Vaidyanathan, G.; Chetal, S.C. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    1995-09-01

    Post shutdown decay heat removal is an important safety requirement in any nuclear system. In order to improve the reliability of this function, Liquid metal (sodium) cooled fast breeder reactors (LMFBR) are equipped with redundant hot pool dipped immersion coolers connected to natural draught air cooled heat exchangers through intermediate sodium circuits. During decay heat removal, flow through the core, immersion cooler primary side and in the intermediate sodium circuits are also through natural convection. In order to establish the viability and validate computer codes used in making predictions, a 1:20 scale experimental model called RAMONA with water as coolant has been built and experimental simulation of decay heat removal situation has been performed at KfK Karlsruhe. Results of two such experiments have been compiled and published as benchmarks. This paper brings out the results of the numerical simulation of one of the benchmark case through a 1D/2D coupled code system, DHDYN-1D/THYC-2D and the salient features of the comparisons. Brief description of the formulations of the codes are also included.

  2. Development of core hot spot evaluation method for decay heat removal by natural circulation under transient conditions in sodium-cooled fast reactor

    Toward the commercialization of fast reactors, a design study of Japan Sodium Cooled Fast Reactor (JSFR) is being performed. In this design study, adoption of fully natural circulation system is being examined as the decay heat removal system from the viewpoints of economic competitiveness and passive safety. This paper describes a new evaluation method of core hot spot for decay heat removal by natural circulation under transient conditions that is necessary for confirming feasibility of the fully natural circulation system. The new method consists of three step analyses in order to include the effects of thermal hydraulic phenomena particular to natural circulation decay heat removal, inter-assembly heat transfer and flow redistribution in fuel assemblies and in the core by buoyancy force, and therefore enables more rational hot spot evaluation rather than conventional ones. The method was applied to an analysis of loss-of-extemal-power event and the result was compared with those by a conventional method and a detailed 3D simulation. It was confirmed that the proposed method can estimate the hot spot with a reasonable degree of conservativeness. (author)

  3. Active heat exchange system development for latent heat thermal energy storage

    Lefrois, R. T.; Mathur, A. K.

    1980-01-01

    Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

  4. Heating of active region cores: Impulsive or steady?

    Tripathi, Durgesh

    The question of active region heating has proven to be highly challenging since its discovery in 1940s. The recent observational facilities have shed new lights towards the understanding of this problem. In this paper we review some of the new measurements to study the heating mechanisms in the hot core loops of active regions using the observations recorded by Solar Ultraviolet Measurements of Emitted Radiation (SUMER) onboard SoHO and the Extreme-ultraviolet Imaging Spectrometer (EIS) aboard Hinode. These new measurements show that the properties of hot core loops are consistent with by impulsive heating -- low frequency nanoflare - scenario. However, the evidences are not strong enough to rule-out steady heating completely. Further measurement using better spectral resolution and temperature coverage is required, which will be provided by Interface Region Imaging Spectrometer (IRIS) and Solar-C in near future.

  5. Brain activity and fatigue during prolonged exercise in the heat

    Hyldig, Tino Hoffmann

    2001-01-01

    We hypothesized that fatigue due to hyperthermia during prolonged exercise in the heat is in part related to alterations in frontal cortical brain activity. The electroencephalographic activity (EEG) of the frontal cortex of the brain was measured in seven cyclists [maximal O2 uptake (VO2max) 4...

  6. Activity size distributions for long-lived radon decay products in aerosols collected in Barcelona (Spain)

    The activity median aerodynamic diameters (AMADs) of long-lived radon decay product (210Pb, 210Po) in aerosols collected in the Barcelona area (Northeast Spain) during the period from April 2006 to February 2008 are presented. The 210Po mean AMAD was 420 nm, while the 210Pb mean AMAD was 500 nm. The temporal evolution of 210Pb and 210Po AMADs shows maxima in autumn and winter and minima in spring and summer. 210Pb AMAD are being used to estimate the mean-residence time of atmospheric aerosols.

  7. Experimental research on a CFCs free thermally activated heat pump

    This paper deals with test results of a new type of Thermally Activated Heat Pump (TAHP) based on the highly efficient Vuilleumier cycle using helium gas as its refrigerant and natural gas as fuel of its external system. These test results show that, in addition to being CFCs free, this heat pump brings about lower CO2 and NOx emissions. (TEC). 7 figs., 6 refs

  8. Significant Isotopes Selection of Core Inventory Based on Decay Heat%基于衰变热的堆芯重要核素选取

    李亢; 于悦海; 陈志宏

    2014-01-01

    衰变热在反应堆设计及安全分析中至关重要,目前计算衰变热主要基于行业标准和专用程序两种方法。通过对PWR燃料组件分别采用两种方法进行计算分析,相互验证了结果。详细分析了停堆不同时刻多种核素对衰变热的贡献,筛选出主要贡献者,为堆芯源项核素的选择提供参考。结果显示约50个核素即可包络停堆后100 h~50 a内95%以上的衰变热贡献。并对标准与程序结果的差异进行了分析,提出了标准适用范围的建议。%Decay heat is extremely important in core design and safety analysis .At pres-ent decay heat calculations are usually based on industrial standards or professional computer codes . Using the two methods to calculate the PWR assembly irradiation respectively ,the validation was done by comparing the results with the two methods and the results were reasonably close .The analytical work was carried out on specific contri-butions made by important isotopes to decay heat at different shutdow n time and the main contributors were screened out as a reference for the core source term inventory selection .The result shows that about 50 isotopes can bound 95% decay heat during 100 h-50 a after shutdown .Discrepancies between the standard and computer code were also investigated .Some instructive advices on suitable region were given for applying the standard .

  9. Increased rates of decay and reduced levels of accumulation of the major poly(A)-associated proteins of Dictyostelium during heat shock and development.

    Manrow, R E; Jacobson, A

    1987-01-01

    Two major polypeptide species, 31,000 Mr (p31) and 31,500 Mr (p31.5), are associated with the 3' poly(A) tails of Dictyostelium mRNAs. We have measured the accumulation of newly synthesized p31 and p31.5 and the decay of preexisting p31 and p31.5 during heat shock and early development. Only trace amounts of newly synthesized p31 and p31.5 accumulate at elevated temperatures, indicating that these polypeptides are not heat shock proteins. In addition, preexisting p31 and p31.5 are rapidly deg...

  10. Preliminary design of a Brayton cycle as a standalone Decay Heat Removal system for the Gas-cooled Fast Reactor

    This paper reports a preliminary design study of a Brayton cycle which would be a dedicated, standalone Decay Heat Removal (DHR) loop of the Gas-cooled Fast Reactor (GFR). In comparison to the DHR reference strategy developed during the GFR pre-conceptual design phase (which was completed by the CEA at the end of 2007), the salient feature of this alternative device would be to combine the energetic autonomy of the natural convection process - which is foreseen for operation at high and medium pressures - to the efficiency of the forced convection process which is foreseen for operation down to very low pressures. An analytical model, the so-called 'Brayton scoping' model, is described in the paper. This is based on simplified thermodynamical and aerodynamical equations and was developed to highlight design choices. First simulations of the proposed device's performance during loss-of-coolant-accident (LOCA) transients have been performed using the CATHARE code, and these are also reported. Analysis of the simulation results are consistent with the first insights obtained from usage of the 'Brayton scoping' model, e.g. the turbomachine accelerates during the depressurization process to tend towards a steady rotational speed value which is inversely proportional to the pressure. For small break LOCA events, the device operates successfully as regards its safety function and delivers to the core a relatively unperturbed cooling mass flowrate as a function of pressure change. However, further studies are required for medium to large break sizes, since certain stability concerns have been met in such cases. For example, an unexpected turbomachine stoppage was induced during the transients, resulting in loss of the necessary core cooling mass flow. (author)

  11. Design of an experiment to measure the decay heat of an irradiated PWR fuel: MERCI experiment; Conception d'une experience de mesure de la puissance residuelle d'un combustible irradie: l'experience MERCI

    Bourganel, St

    2002-11-01

    After a reactor shutdown, a significant quantity of energy known as 'decay heat' continues to be generated from the irradiated fuel. This heat source is due to the disintegration energy of fission products and actinides. Decay heat determination of an irradiated fuel is of the utmost importance for safety analysis as the design cooling systems, spent fuel transport, or handling. Furthermore, the uncertainty on decay heat has a straight economic impact. The unloading fuel spent time is an example. The purpose of MERCI experiment (irradiated fuel decay heat measurement) consists in qualifying computer codes, particularly the DARWIN code system developed by the CEA in relation to industrial organizations, as EDF, FRAMATOME and COGEMA. To achieve this goal, a UOX fuel is irradiated in the vicinity of the OSIRIS research reactor, and then the decay heat is measured by using a calorimeter. The objective is to reduce the decay heat uncertainties from 8% to 3 or 4% at short cooling times. A full simulation on computer of the MERCI experiment has been achieved: fuel irradiation analysis is performed using transport code TRIPOLI4 and evolution code DARWIN/PEPIN2, and heat transfer with CASTEM2000 code. The results obtained are used for the design of this experiment. Moreover, we propose a calibration procedure decreasing the influence of uncertainty measurements and an interpretation method of the experimental results and evaluation of associated uncertainties. (author)

  12. A methodology for fast and accurate decay heat calculations for in-pool used fuel assemblies developed at AREVA La Hague reprocessing facility

    The evaluation of the decay heat released from used fuels stored in an interim storage pool is a crucial issue for safety and operation. This paper presents a methodology developed at the AREVA NC La Hague reprocessing facility in order to perform a fast and accurate assessment of the decay heat for a pool containing a large variety of fuel assemblies with different features (kind of reactor, initial composition, number of irradiation cycles, operating power, outage length) and cooling times ranging from 6 months to 60 years. The key aspect of the methodology relies on the fact that, for cooling times higher than 6 months, only a very short number of isotopes significantly contribute to the overall decay heat. The methodology uses results from calculations performed by the industrial depletion code CESAR and takes benefit from the experimental validation of CEA reference depletion package DARWIN. A full CESAR calculation at a given cooling time for each assembly allows building up a reference database: for any cooling time higher than the reference one, a simplified on-line calculation involving less than 30 isotopes is performed, and all approximations made are covered by the mean of biases relying on pre-evaluated coefficients. Results for an application to a 10,000-used-fuel-assembly interim storage pool are given. (author)

  13. Measuring the activity of neutron-activation detectors using gamma-spectroscopy technique in the presence of positron decay

    The present paper is of methodical character and is aimed at drawing experimentators' attention to the systematic error sources occurring on positron-decay nuclide activity measuring with gamma spectrometric method. The paper deals with summing in the detection unit the signals from the measured photons with energy Eph to those from annihilation radiation photons. Summation results in decrease of the area under the total energy absorption peak for measured photons and, as the consequence, in decrease of the sample external radiation measured value

  14. Canonical Poly(A Polymerase Activity Promotes the Decay of a Wide Variety of Mammalian Nuclear RNAs.

    Stefan M Bresson

    2015-10-01

    Full Text Available The human nuclear poly(A-binding protein PABPN1 has been implicated in the decay of nuclear noncoding RNAs (ncRNAs. In addition, PABPN1 promotes hyperadenylation by stimulating poly(A-polymerases (PAPα/γ, but this activity has not previously been linked to the decay of endogenous transcripts. Moreover, the mechanisms underlying target specificity have remained elusive. Here, we inactivated PAP-dependent hyperadenylation in cells by two independent mechanisms and used an RNA-seq approach to identify endogenous targets. We observed the upregulation of various ncRNAs, including snoRNA host genes, primary miRNA transcripts, and promoter upstream antisense RNAs, confirming that hyperadenylation is broadly required for the degradation of PABPN1-targets. In addition, we found that mRNAs with retained introns are susceptible to PABPN1 and PAPα/γ-mediated decay (PPD. Transcripts are targeted for degradation due to inefficient export, which is a consequence of reduced intron number or incomplete splicing. Additional investigation showed that a genetically-encoded poly(A tail is sufficient to drive decay, suggesting that degradation occurs independently of the canonical cleavage and polyadenylation reaction. Surprisingly, treatment with transcription inhibitors uncouples polyadenylation from decay, leading to runaway hyperadenylation of nuclear decay targets. We conclude that PPD is an important mammalian nuclear RNA decay pathway for the removal of poorly spliced and nuclear-retained transcripts.

  15. To the safety conception of the high temperature reactor with natural heat removal decay in teh case of accidents

    On September 22, 1970, for the first time an accident simulation experiment with complete failure of the forced core cooling and the nuclear shut-down system was performed in the AVR-reactor: Due to a small heat-up of the fuel the nuclear chain-reaction was interrupted and an overheating of the core and structure was prevented due to the natural heat-convection. On the basis of the meanwhile developed computer-methods and accompanying experimental investigations it is now possible to determine exactly the behaviour of the non actively controlled core of the high temperature reactor, and to understand better the course of the AVR-experiments. On the same basis the potential and the limits of the safety conception realized in the AVR with self-stabilization in the case of accident can be determined. Such a small high temperature reactor as for example the HTR-modul of the KWU, which is characterized by a reliable and simple safety-technique with a minimum of expensive active systems, can be realized using a 2-zone-core up to a unit size of nearly 250 MW(th). (orig.)

  16. Heat and mass flux estimation of modern seafloor hydrothermal activity

    ZHAI Shikui; WANG Xingtao; YU Zenghui

    2006-01-01

    Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of seawater properties. Currently, estimating heat flux is based on the observation data of hydrothermal smokers, low-temperature diffusive flow and mid-ocean ridge mainly. But there are some faults, for example, there is lack of a concurrent conductive item in estimating the heat flux by smokers and the error between the half-space cooling model and the observation data is too large. So, three kinds of methods are applied to re-estimating the heat flux of hydrothermal activity resepectively, corresponding estimation is 97.359 GW by hydrothermal smoker and diffusive flow, 84.895 GW by hydrothermal plume, and 4.11 TW by exponential attenuation method put forward by this paper. Research on mass flux estimation is relatively rare, the main reason for this is insufficient field observation data. Mass fluxes of different elements are calculated using hydrothermal vent fluid data from the TAG hydrothermal area on the Mid-Atlantic Ridge for the first time. Difference of estimations by different methods reflects the researching extent of hydrothermal activity, and systematically in-situ observation will help to estimate the contribution of hydrothermal activity to ocean chemical environment, ocean circulation and global climate precisely.

  17. Optimization of irradiation decay and counting times in nuclear activation analysis using short-lived nuclides

    This work describes a method and outlines a procedure for optim- ization of an activation analysis with respect to the experimental times, irradiation time, t(subi), decay time and counting time. The method is based on the 'minimum relative standard deviation criterion', and specially designed for the use on short-lived nuclides. A computer program, COMB1, is written in the BASIC language in order to make the calculations easier and faster. It is intended to be understandable, and easily applicable on a computer of modest size. Time and cost are important factors, especially for routine analysis on a service basis. In such cases one can often allow a controlled reduction in the analysis quality (through a higher relative standard deviation). The procedure outlined can therefore help find acceptable conditions by calculation of the 'best practical' (or reasonable) experimental time values, and the minimum number of accumulation cycles necessary to fulfil the requirements given. (Auth.)

  18. Comparison of the effect of gamma irradiation, heat-radiation combination, and sulphur dioxide generating pads on decay and quality of grapes

    Effect of gamma irradiation, heat-radiation combination and in-package sulphur dioxide fumigation on fungal decay, and quality of seedless grape cultivars, Thompson, Sonaka and Tas-A-Ganesh was evaluated under different storage regimes. Irradiation at 2 kGy or a combination of hot water dip (50 degC, 5 min), plus irradiation (1 kGy) showed less spoilage due to Rhizopus spp. and Botrytis spp. in grapes packaged in tissue paper lined boxes and stored at 4 deg, 15 deg and 25 degC. Storage in polyethylene lined boxes increased the fungal rot. In-package sulphur dioxide generating pad was most effective for control of decay in polyethylene lined boxes stored at 10 deg and 20 degC, but caused berry bleaching. Irradiation at 2.5 or 3.5 kGy controlled decay at 10 degC, but not so effectively at 20 degC. Organoleptic quality, berry firmness, and soluble solids were not affected by irradiation, but decreases in titratable acids and ascorbic acid were recorded. Packaging in polyethylene lined boxes retained berry turgidity, while slight shrivelling occurred in tissue paper lined boxes. The results indicate that gamma irradiation has potential as an alternative to sulphur dioxide fumigation for decay control during shipping and storage. (author). 20 refs., 4 tabs

  19. Nuclide Importance to Criticality Safety, Decay Heating, and Source Terms Related to Transport and Interim Storage of High-Burnup LWR Fuel

    Gauld, I. C.; Ryman, J. C.

    2000-12-11

    This report investigates trends in the radiological decay properties and changes in relative nuclide importance associated with increasing enrichments and burnup for spent LWR fuel as they affect the areas of criticality safety, thermal analysis (decay heat), and shielding analysis of spent fuel transport and storage casks. To facilitate identifying the changes in the spent fuel compositions that most directly impact these application areas, the dominant nuclides in each area have been identified and ranked by importance. The importance is investigated as a function of increasing burnup to assist in identifying the key changes in spent fuel characteristics between conventional- and extended-burnup regimes. Studies involving both pressurized water-reactor (PWR) fuel assemblies and boiling-water-reactor (BWR) assemblies are included. This study is seen to be a necessary first step in identifying the high-burnup spent fuel characteristics that may adversely affect the accuracy of current computational methods and data, assess the potential impact on previous guidance on isotopic source terms and decay-heat values, and thus help identify areas for methods and data improvement. Finally, several recommendations on the direction of possible future code validation efforts for high-burnup spent fuel predictions are presented.

  20. Activity measurements and gamma emission intensities determination in the decay of Zn65

    Over the last twenty years, a number of laboratories have participated to the Systeme International de Reference (SIR BIPM) and it appeared that the mass activity of 65Zn determined by the gamma-ray spectrometry was less by about 2% than the one determined by using 4πβ-γ coincidence counting. An international exercise EUROMET, action 721, was organized with the objective of improving the knowledge of decay data in the 65Zn disintegration. Nine laboratories participated, sending results for the activity measurement and the 1115 keV gamma emission intensity. For the activity measurement, the participants used the 4πβ-γ coincidence method mainly, resulting values and uncertainty budgets are described. From the new gamma emission intensities measured in this exercise and, taking into account previous published values, the intensity of the 1115 keV gamma emission has been determined being equal to: 50.22 (11) %. This new value must lead to derive activity values higher than those previously obtained, reducing the difference, with other techniques of measurement, to 1 %. Moreover, the uncertainty on the emission intensity value has been divided by a factor of two. (authors)

  1. PEPIN, Methodology for Computing Concentrations, Activities, Gamma-Ray Spectra, and Residual Heat from Fission Products

    1 - Description of program or function: The concentrations, activities, gamma-ray spectra and residual heat from fission products can be calculated as a function of time for instantaneous fission or for one or more irradiation steps. 2 - Methods: Using the basic data in the libraries, the PEPIN code solves the differential equations satisfied by the fission product concentrations. Data Libraries: Independent Yields Library: 8 independent yields for 235U, 238U, 239U, 232U, 233U. Chain library: Precursor chain file for 635 nuclides. Gamma-Ray Energies Library: Average beta and gamma-ray energies in increasing order. 3 - Restrictions on the complexity of the problem: The number of nuclides must not exceed 650. The number of Gamma-Rays must not exceed 8500. The number of decay times must not exceed 59. The number of irradiation steps must not exceed 40

  2. A decaying factor accounts for contained activity in neuronal networks with no need of hierarchical or modular organization

    Amancio, Diego R; Costa, Luciano da F

    2012-01-01

    The mechanisms responsible for contention of activity in systems represented by networks are crucial in various phenomena, as in diseases such as epilepsy that affects the neuronal networks, and for information dissemination in social networks. The first models to account for contained activity included triggering and inhibition processes, but they cannot be applied to social networks where inhibition is clearly absent. A recent model showed that contained activity can be achieved with no need of inhibition processes provided that the network is subdivided in modules (communities). In this paper, we introduce a new concept inspired in the Hebbian theory through which activity contention is reached by incorporating a dynamics based on a decaying activity in a random walk mechanism preferential to the node activity. Upon selecting the decay coefficient within a proper range, we observed sustained activity in all the networks tested, viz. random, Barabasi-Albert and geographical networks. The generality of this ...

  3. Heated Proteins are Still Active in a Functionalized Nanoporous Support

    Chen, Baowei; Qi, Wen N.; Li, Xiaolin; Lei, Chenghong; Liu, Jun

    2013-07-08

    We report that even under the heated condition, the conformation and activity of a protein can be hoarded in a functionalized nanoporous support via non-covalent interaction, although the hoarded protein was not exhibiting the full protein activity, the protein released subsequently still maintained its native conformation and activity. Glucose oxidase (GOX) was spontaneously and largely entrapped in aminopropyl-functionalized mesoporous silica (NH2-FMS) at 20 oC via a dominant electrostatic interaction. Although FMS-GOX displayed 45% activity of the free enzyme in solution, the GOX released from FMS exhibited its 100% activity prior to the entrapment. Surprisingly, the released GOX from FMS still maintained 89% of its initial activity prior to the entrapment after FMS-GOX was incubated at 60 oC for 1 h prior to release, while the free GOX in solution lost nearly all activity under the same incubation. Intrinsic fluorescence emission of GOX and native electrophoresis demonstrated that the heating resulted in significant conformational changes and oligomeric structures of the free GOX, but FMS efficiently maintained the thermal stability of GOX therein and resisted the thermal denaturation and oligomeric aggregation.

  4. Corrections from extending dead times with activity measurements on radionuclides decaying via metastable states

    Funck, E.

    1985-05-15

    The dead-time corrections for an extending dead time are analyzed for measurements on radionuclides decaying via metastable states and correction formulas are developed. It is shown that for large dead times with lambdatau >> 1(lambda = decay constant, tau = dead time) the dead-time correction approximates the usual case of a prompt decay besides a term that enlarges the dead-time correction. (orig.).

  5. Corrections from extending dead times with activity measurements on radionuclides decaying via metastable states

    Funck, E. (Physikalisch-Technische Bundesanstalt, Braunschweig (Germany, F.R.))

    1985-05-15

    The dead-time corrections for an extending dead time are analyzed for measurements on radionuclides decaying via metastable states and correction formulas are developed. It is shown that for large dead times with lambda tau >> 1(lambda = decay constant, tau = dead time) the dead-time correction approximates the usual case of a prompt decay besides a term that enlarges the dead-time correction.

  6. Corrections from extending dead times with activity measurements on radionuclides decaying via metastable states

    The dead-time corrections for an extending dead time are analyzed for measurements on radionuclides decaying via metastable states and correction formulas are developed. It is shown that for large dead times with lambdatau >> 1(lambda = decay constant, tau = dead time) the dead-time correction approximates the usual case of a prompt decay besides a term that enlarges the dead-time correction. (orig.)

  7. Molecular Dynamics Simulation on Longitudinal Optical Phonon Mode Decay and Heat Transport in a Silicon Nano-Structure Covered with Oxide Films

    Zushi, Tomofumi; Kamakura, Yoshinari; Taniguchi, Kenji; Ohdomari, Iwao; Watanabe, Takanobu

    2011-01-01

    A series of molecular dynamics (MD) simulations have been conducted to investigate the heat transport in terms of the phonon dynamics in nanoscale silicon (Si). This work is motivated by a concern over the stagnation of heat at the drain region of nanoscopic transistors, owing to this, a large amount of optical phonons with a low group velocity are emitted from hot electrons, which are ballistically transferred through channel region. The point of this work is the explicit inclusion of the SiO2 film in the MD simulation of the Si lattice. The calculation results show that longitudinal optical (LO) phonons decay faster as Si lattice thickness decreases and turn into acoustic phonons. In contrast, thermal diffusion rate decreases with Si lattice thickness. Both the decay rate of LO phonons and thermal diffusion rate are not governed by oxide thickness. These results imply that the phonon scattering at the SiO2/Si interface is enhanced by thinning the Si layer. In nanoscopic devices, a thin Si layer is effective in diminishing the optical phonons with a low group velocity, but it hinders the subsequent heat transport.

  8. Laser-heating-based active optics for synchrotron radiation applications.

    Yang, Fugui; Li, Ming; Gao, Lidan; Sheng, Weifan; Liu, Peng; Zhang, Xiaowei

    2016-06-15

    Active optics has attracted considerable interest from researchers in synchrotron radiation facilities because of its capacity for x-ray wavefront correction. Here, we report a novel and efficient technique for correcting or modulating a mirror surface profile based on laser-heating-induced thermal expansion. An experimental study of the characteristics of the surface thermal deformation response indicates that the power of a milliwatt laser yields a bump height as low as the subnanometer scale and that the variation of the spot size modulates the response function width effectively. In addition, the capacity of the laser-heating technique for free-form surface modulation is demonstrated via a one-dimensional surface correction experiment. The developed method is a promising new approach toward effective x-ray active optics coupled with at-wavelength metrology techniques. PMID:27304296

  9. Laser-heating-based active optics for synchrotron radiation applications

    Yang, Fugui; Zhang, Xiaowei

    2016-01-01

    Active optics has attracted considerable interest from researchers in synchrotron radiation facilities, because of its capacity for x-ray wavefront correction. Here, we report a novel and efficient technique for correcting or modulating a mirror surface profile based on laser-heating-induced thermal expansion. An experimental study of the characteristics of the surface thermal deformation response indicates that the power of a milliwatt laser yields a bump height as low as sub-nanometer scale, and that variation of the spot size modulates the response function width effectively. In addition, the capacity of the laser-heating technique for free-form surface modulation is demonstrated via a surface correction experiment. The developed method is a promising new approach towards effective x-ray active optics coupled with at-wavelength metrology techniques.

  10. Conceptual Design of Ultra-long-life Core Fast Reactor (UCFR) with Ga-based Passive Decay Heat Removal System (PDHRS)

    UCFR (Ultra-long-life Core Fast Reactor) is a 260MWth /100MWe sodium-cooled fast reactor which requires no on-site refueling and meets the need for future nuclear energy systems. UCFR is a pool type reactor with metallic fuels, four intermediate heat exchangers, two steam generators, and passive decay heat removal systems. Because gallium has the chemical reaction safety such as low oxygen reactivity compared to sodium, it can be used as a boundary material between sodium and atmosphere to enhance the nuclear safety of UCFR. In this research, design studied for neutronics and thermal-hydraulics are included. The safety performance of UCFR will be analyzed with MARS-LMR. Although MARS-LMR was originally intended for a safety analysis of liquid metal-cooled reactor, gallium properties were newly added to this code which is applicable for gallium-cooled systems. The properties of various liquid metals are indicated in table II. Considering needs to improve uranium utilization and solve the nuclear proliferation, ultra-long cycle fast reactor has been developed. UCFR is a 260MWth/100MWe sodium-cooled fast reactor which requires no on-site refueling during design period with metallic fuels (U-5Zr), HT-9 cladding, four intermediate heat exchangers, two steam generators, and Ga-based PDHRS. Through this paper, new PDHRS using gallium that can be remove decay heat passively for an infinite time is suggested. In Ga-based PDHRS, the both water and air as an ultimate heat sink will be can be considered because gallium has the chemical reaction safety. In this research, design study for neutronics and thermal-hydraulics were also included. For safety analysis of UCFR using MARS-LMR, detailed design of UCFR with Ga-based PDHRS will be required

  11. Calculations of criticality, nuclide compositions, decay heat and sources for WWER-440 fuel by new version of the SCALE 5 code

    In this article are compared theoretical results by new version of the SCALE5 code with experiments or other theoretical calculation for: 1. criticality: -measurement on ZR-6 and LR-0; - numerical benchmark No. 1.3 and 4 (CB1, CB3, CB4); 2. nuclide compositions: - measurement in Kurchatov institute for 3,6 %; - measurement in JAERI(PWR 17x17); - numerical benchmark No. 2-Source (CB2); 3. sources and decay heat:- numerical benchmark No.2-Source (CB2-S); The focus is on modules KENO, TRITON and ORIGEN-S (Authors)

  12. A decaying factor accounts for contained activity in neuronal networks with no need of hierarchical or modular organization

    Amancio, Diego R.; Oliveira, Osvaldo N., Jr.; Costa, Luciano da F.

    2012-11-01

    The mechanisms responsible for containing activity in systems represented by networks are crucial in various phenomena, for example, in diseases such as epilepsy that affect the neuronal networks and for information dissemination in social networks. The first models to account for contained activity included triggering and inhibition processes, but they cannot be applied to social networks where inhibition is clearly absent. A recent model showed that contained activity can be achieved with no need of inhibition processes provided that the network is subdivided into modules (communities). In this paper, we introduce a new concept inspired in the Hebbian theory, through which containment of activity is achieved by incorporating a dynamics based on a decaying activity in a random walk mechanism preferential to the node activity. Upon selecting the decay coefficient within a proper range, we observed sustained activity in all the networks tested, namely, random, Barabási-Albert and geographical networks. The generality of this finding was confirmed by showing that modularity is no longer needed if the dynamics based on the integrate-and-fire dynamics incorporated the decay factor. Taken together, these results provide a proof of principle that persistent, restrained network activation might occur in the absence of any particular topological structure. This may be the reason why neuronal activity does not spread out to the entire neuronal network, even when no special topological organization exists. .

  13. A decaying factor accounts for contained activity in neuronal networks with no need of hierarchical or modular organization

    The mechanisms responsible for containing activity in systems represented by networks are crucial in various phenomena, for example, in diseases such as epilepsy that affect the neuronal networks and for information dissemination in social networks. The first models to account for contained activity included triggering and inhibition processes, but they cannot be applied to social networks where inhibition is clearly absent. A recent model showed that contained activity can be achieved with no need of inhibition processes provided that the network is subdivided into modules (communities). In this paper, we introduce a new concept inspired in the Hebbian theory, through which containment of activity is achieved by incorporating a dynamics based on a decaying activity in a random walk mechanism preferential to the node activity. Upon selecting the decay coefficient within a proper range, we observed sustained activity in all the networks tested, namely, random, Barabási–Albert and geographical networks. The generality of this finding was confirmed by showing that modularity is no longer needed if the dynamics based on the integrate-and-fire dynamics incorporated the decay factor. Taken together, these results provide a proof of principle that persistent, restrained network activation might occur in the absence of any particular topological structure. This may be the reason why neuronal activity does not spread out to the entire neuronal network, even when no special topological organization exists. (paper)

  14. Effects of heat-activated persulfate oxidation on soil microorganisms

    Tsitonaki, Aikaterini; Smets, Barth F.; Bjerg, Poul Løgstrup

    2008-01-01

    The effects of heat-activated persulfate on indigenous microorganisms and microcosms augmented with Pseudomonas putida KT2440 were studied in laboratory batch reactors with aquifer material. Microscopic enumeration was used to measure the changes in cell density, and acetate consumption was used to....../L). The results emphasize the necessity of using multiple toxicity assays and indigenous cultures in order to realistically assess the potential effects of in situ chemical oxidation on soil microorganisms. A comparison to other studies suggests that the effects of activated persulfate on soil...

  15. Activation of Polyphenol Oxidase in Dormant Wild Oat Caryopses by a Seed-Decay Isolate of Fusarium avenaceum

    Incubation of dormant wild oat (Avena fatua L., isoline M73) caryopses for 1 to 3 days with Fusarium avenaceum seed-decay isolate F.a.1 induced activity of the plant defense enzyme polyphenol oxidase (PPO). Both extracts and leachates obtained from F.a.1-treated caryopses had decreased abundance of ...

  16. [Physical activity in the heat: physiology of hydration recommendations].

    Koulmann, N; Banzet, S; Bigard, A X

    2003-01-01

    Physical exercise in the heat causes severe disturbances in homeostasis. The need for evaporative thermolysis is increased due to the combination of endogenous and exogenous heat production. Despite a marked increase in cardiac output, muscles and skin must compete for sufficient blood flow. In addition progressive dehydration can impair the ability of the cardiocirculatory to adjust adequately. The most serious risk associated with exercise in a hot environment is heat stroke. Although deleterious effects of dehydration occur only if large amounts of water and electrolytes are lost without being replaced, even moderate fluid depletion can reduce both physical and cognitive performance. Another mechanism by which heat exposure directly affects performance involves core temperature elevation which can induce profound changes in muscular activity and energy consumption, thereby accelerating exhaustion. Prevention of deleterious effects on health and performance requires an effective rehydration strategy to maintain body fluid balance. This strategy must optimize all three potentially limiting factors for fluid replacement, i.e., fluid intake, gastric emptying, and intestinal absorption. Practical guidelines are given to answer the questions of when, what and how much to drink. PMID:15077428

  17. Investigating the jet activity accompanying the production at the LHC of a massive scalar particle decaying into photons

    Fuks, Benjamin; Park, Seong Chan; Seo, Min-Seok

    2016-01-01

    We study the jet activity that accompanies the production by gluon fusion of a new physics scalar particle decaying into photons at the LHC. In the considered scenarios, both the production and decay mechanisms are governed by loop-induced interactions involving a heavy colored state. We show that the presence of large new physics contributions to the inclusive diphoton invariant-mass spectrum always implies a significant production rate of non-standard diphoton events containing extra hard jets. We investigate the existence of possible handles that could provide a way to obtain information on the underlying physics behind the scalar resonance, and this in a wide mass window.

  18. Effect of heat treatment on antimycotic activity of Sahara honey

    Moussa Ahmed; Saad Aissat; Noureddine Djebli

    2014-01-01

    Objective: To evaluate the influence of the temperature on honey colour, polyphenol contents and antimycotic capacity and to evaluate the correlation between these parameters. Methods:Sahara honey were heated up to 25, 50, 75 and 100 °C for 15, 30 and 60 min, and their colour intensity, polyphenol contents and antimycotic capacity. The Folin-Ciocalteu test was used to determine the total polyphenol contents (TPC). The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans (C. albicans) and Candida glabrata (C. glabrata). Results:Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey, with the average value of 0.78 mg of gallic acid per kg of honey. The TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 mg. The minimal inhibitory concentrations before heat-treatment of Sahara honey against C. albicans and C. glabrata ranged from 3.06%-12.5% and 50% respectively. After heat-treatment the minimal inhibitory concentrations between 12.5% and 50% for C. albicans and C. glabrata, respectively. The diameters of inhibition zones of Sahara honey with 50% concentration varied from (12.67-15.00) mm by C. albicans to (14.33-15.67) mm by C. glabrata. The diameters of inhibition zones after heat-treatment at 25 and 50 °C for 15.30 and 60 min ranged from (2.00-18.67) mm by C. albicans to (8.00-16.67) mm by C. glabrata. Statistically significant relations between the TPC and the colour intensity of Sahara honey (r=0.99, P Conclusions:To our knowledge this is the first report on the antimycotic capacity of Sahara honey.

  19. Impact of active geomagnetic conditions on stimulated radiation during ionospheric second electron gyroharmonic heating

    Bordikar, M. R.; Scales, W. A.; Mahmoudian, A.; Kim, H.; Bernhardt, P. A.; Redmon, R.; Samimi, A. R.; Brizcinski, S.; McCarrick, M. J.

    2014-01-01

    Recently, narrowband emissions ordered near the H+ (proton) gyrofrequency (fcH) were reported in the stimulated electromagnetic emission (SEE) spectrum during active geomagnetic conditions. This work presents new observations and theoretical analysis of these recently discovered emissions. These emission lines are observed in the stimulated electromagnetic emission (SEE) spectrum when the transmitter is tuned near the second electron gyroharmonic frequency (2fce) during recent ionospheric modification experiments at the High Frequency Active Auroral Research (HAARP) facility near Gakona, Alaska. The spectral lines are typically shifted below and above the pump wave frequency by harmonics of a frequency roughly 10% less than fcH (≈ 800 Hz) with a narrow emission bandwidth less than the O+ gyrofrequency (≈ 50 Hz). However, new observations and analysis of emission lines ordered by a frequency approximately 10% greater than fcH are presented here for the first time as well. The interaction altitude for the heating for all the observations is in the range of 160 km up to 200 km. As described previously, proton precipitation due to active geomagnetic conditions is considered as the reason for the presence of H+ ions known to be a minor background constituent in this altitude region. DMSP satellite observations over HAARP during the heating experiments and ground-based magnetometer and riometer data validate active geomagnetic conditions. The theory of parametric decay instability in multi-ion component plasma including H+ ions as a minority species described in previous work is expanded in light of simultaneously observed preexisting SEE features to interpret the newly reported observations. Impact of active geomagnetic conditions on the SEE spectrum as a diagnostic tool for proton precipitation event characterization is discussed.

  20. The status of studies using RAMONA and NEPTUN models on decay heat removal by natural convection for the European Fast Reactor

    An extensive Research and Development Program is being carried out to support the Direct Reactor Cooling System which relies solely on natural convection for decay heat removal during all loss of station service power. Experiments have been performed in water test rigs of different scales. RAMONA is a 1:20 and NEPTUN a 1:5 scaled three dimensional model. Similar steady state tests have been carried out in both models. For the RAMONA test facility about 100 transient experiments have been performed. These experiments allow to study the in-vessel thermohydraulics in the transition regime from forced nominal to natural convection conditions after scram. All these experiments provide a basis for the verification of computer programs. It is demonstrated by experimental results, that the decay heat can be removed safely by means of natural convection under different variations of parameters. It is also shown by the calculations performed with the 3-D computer code FLUTAN that the steady state process and transition regime is mastered both qualitatively and quantitatively even for the very complex geometry of the NEPTUN model. (author)

  1. Study on occurrence possibility of dust explosion, hydrogen explosion and decay heat for safety of a process of manufacturing for DUPIC fuel

    Park, S. H.; Park, J. J.; Lee, H. H.; Shin, J. M.; Yang, M. S. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-02-01

    DUPIC process is a dry powder processing technology to manufacture CANDU fuel from spent PWR fuel through powder fabrication processes. The DUPIC process consist of the slitting of the spent PWR fuel rods, OREOX processing to produce the powder feedstock, the milling of the produced powder, the granulation of the milled powder, an the mixing of the granulated powder with pressing lubricants, the pelletizing and sintering, and the welding of the fuel rod by laser welding technique. All these processes should be conducted by remote means in a hot-cell environment(M6 hot-cell). Since this process contains powder handling of highly radioactive spent fuel and reduction process with hydrogen, prevention of dust explosion, hydrogen explosion and safe control on decay heat of the fuel is very important. Therefore, this study estimated an occurrence possibility of dust explosion, hydrogen explosion and decay heat for safety of a process of manufacturing for DUPIC fuel. 9 refs., 12 figs., 29 tabs. (Author)

  2. Integration of functional reliability analysis with hardware reliability: An application to safety grade decay heat removal system of Indian 500 MWe PFBR

    A passive system can fail either due to classical mechanical failure of components, referred to as hardware failure, or due to the failure of physical phenomena to fulfill the intended function, referred to as functional failure. In this paper a methodology is discussed for the integration of these two kinds of unreliability and applied to evaluate the integrated failure probability of the passive decay heat removal system of Indian 500 MWe prototype fast breeder reactor (PFBR). The probability of occurrence of various system hardware configurations is evaluated using the fault tree method and functional failure probabilities on the corresponding configurations are determined based on the overall approach reported in the reliability methods for passive system (RMPS) project. The variation of functional reliability with time, which is coupled to the probability of occurrence of various hardware system configurations is studied and incorporated in the integrated reliability analysis. It is observed that this consideration of the dependence of functional reliability on time will give significant advantages on system reliability. The integrated reliability analysis is also explained using an event tree. The impact of the provision for forced circulation in the primary circuit on functional reliability is also studied with this procedure and it is found that the forced circulation capability helps to bring down the total decay heat removal failure probability by lowering the peak temperatures after the reactor shut down.

  3. Decay Heat and Dryout Behavior of Spent Fuel Storage Pool with ORIGEN-ARP and MARS codes for the Station Blackout Accident

    Spent nuclear fuels are stored in spent fuel storage pool (SFP) in nuclear power plants. SFP should be designed and operated to prevent the spent fuels from being critical and have a shielding capability against radiation. Borated water is usually used to prevent the fuel from being critical and provide radiation shielding. Borated water is also used for removal of the decay heat from the spent fuels. Since the fuels may be expected to be fail without cooling, the SFP should be maintained its temperature lower than safety limit. Electric power is always required for the SFP cooling system during all modes of operation to maintain cooling capability of SFP water. In this paper, we performed analysis of decay heat and dryout behavior of spent fuel pool for the station blackout accident (complete loss of AC power). The accident can be regarded as a most challenging one to the SFP and its support system. As a reference, SFP of Ulchin Unit 3 and its state of maximum storage is considered

  4. Using the Inflection Points and Rates of Growth and Decay to Predict Levels of Solar Activity

    Wilson, Robert M.; Hathaway, David H.

    2008-01-01

    The ascending and descending inflection points and rates of growth and decay at specific times during the sunspot cycle are examined as predictors for future activity. On average, the ascending inflection point occurs about 1-2 yr after sunspot minimum amplitude (Rm) and the descending inflection point occurs about 6-7 yr after Rm. The ascending inflection point and the inferred slope (including the 12-mo moving average (12-mma) of (Delta)R (the month-to-month change in the smoothed monthly mean sunspot number (R)) at the ascending inflection point provide strong indications as to the expected size of the ongoing cycle s sunspot maximum amplitude (RM), while the descending inflection point appears to provide an indication as to the expected length of the ongoing cycle. The value of the 12-mma of (Delta)R at elapsed time T = 27 mo past the epoch of RM (E(RM)) seems to provide a strong indication as to the expected size of Rm for the following cycle. The expected Rm for cycle 24 is 7.6 +/- 4.4 (the 90-percent prediction interval), occurring before September 2008. Evidence is also presented for secular rises in selected cycle-related parameters and for preferential grouping of sunspot cycles by amplitude and/or period.

  5. THE AIMS AND ACTIVITIES OF THE INTERNATIONAL NETWORK OF NUCLEAR STRUCTURE AND DECAY DATA EVALUATORS.

    NICHOLS,A.L.; TULI, J.K.

    2007-04-22

    International Network of Nuclear Structure and Decay Data (NSDD) Evaluators consists of a number of evaluation groups and data service centers in several countries that appreciate the merits of working together to maintain and ensure the quality and comprehensive content of the ENSDF database (Evaluated Nuclear Structure Data File). Biennial meetings of the network are held under the auspices of the International Atomic Energy Agency (IAEA) to assign evaluation responsibilities, monitor progress, discuss improvements and emerging difficulties, and agree on actions to be undertaken by individual members. The evaluated data and bibliographic details are made available to users via various media, such as the journals ''Nuclear Physics A'' and ''Nuclear Data Sheets'', the World Wide Web, on CD-ROM, wall charts of the nuclides and ''Nuclear Wallet Cards''. While the ENSDF master database is maintained by the US National Nuclear Data Center at the Brookhaven National Laboratory, these data are also available from other nuclear data centers including the IAEA Nuclear Data Section. The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy, in cooperation with the IAEA, organizes workshops on NSDD at regular intervals. The primary aims of these particular workshops are to provide hands-on training in the data evaluation processes, and to encourage new evaluators to participate in NSDD activities. The technical contents of these NSDD workshops are described, along with the rationale for the inclusion of various topics.

  6. A Stress-Activated, p38 Mitogen-Activated Protein Kinase–ATF/CREB Pathway Regulates Posttranscriptional, Sequence-Dependent Decay of Target RNAs

    Gao, Jun; Wagnon, Jacy L.; Protacio, Reine M.; Glazko, Galina V.; Beggs, Marjorie; Raj, Vinay

    2013-01-01

    Broadly conserved, mitogen-activated/stress-activated protein kinases (MAPK/SAPK) of the p38 family regulate multiple cellular processes. They transduce signals via dimeric, basic leucine zipper (bZIP) transcription factors of the ATF/CREB family (such as Atf2, Fos, and Jun) to regulate the transcription of target genes. We report additional mechanisms for gene regulation by such pathways exerted through RNA stability controls. The Spc1 (Sty1/Phh1) kinase-regulated Atf1-Pcr1 (Mts1-Mts2) heterodimer of the fission yeast Schizosaccharomyces pombe controls the stress-induced, posttranscriptional stability and decay of sets of target RNAs. Whole transcriptome RNA sequencing data revealed that decay is associated nonrandomly with transcripts that contain an M26 sequence motif. Moreover, the ablation of an M26 sequence motif in a target mRNA is sufficient to block its stress-induced loss. Conversely, engineered M26 motifs can render a stable mRNA into one that is targeted for decay. This stress-activated RNA decay (SARD) provides a mechanism for reducing the expression of target genes without shutting off transcription itself. Thus, a single p38-ATF/CREB signal transduction pathway can coordinately induce (promote transcription and RNA stability) and repress (promote RNA decay) transcript levels for distinct sets of genes, as is required for developmental decisions in response to stress and other stimuli. PMID:23732911

  7. DNA polymerase activity in heat killing and hyperthermic radiosensitization of mammalian cells as observed after fractionated heat treatments.

    Jorritsma, J B; Burgman, P; Kampinga, H H; Konings, A W

    1986-03-01

    Possible relations between hyperthermic inactivation of alpha and beta DNA polymerase activity and hyperthermic cell killing or hyperthermic radiosensitization were investigated. Ehrlich Ascites Tumor (EAT) cells and HeLa S3 cells were treated with fractionated doses of hyperthermia. The heating schedules were chosen such that the initial heat treatment resulted in either thermotolerance or thermosensitization (step-down heating) for the second heat treatment. The results show that for DNA polymerase activity and heat radiosensitization (cell survival) no thermotolerance or thermosensitization is observed. Thus hyperthermic cell killing and DNA polymerase activity are not correlated. The correlation of hyperthermic radiosensitization and DNA polymerase activity was substantially less than observed in previous experiments with normotolerant and thermotolerant HeLa S3 cells. We conclude that alpha and beta DNA polymerase inactivation is not always the critical cellular process responsible for hyperthermic cell killing or hyperthermic radiosensitization. Other possible cellular systems that might determine these processes are discussed. PMID:3754338

  8. DNA polymerase activity in heat killing and hyperthermic radiosensitization of mammalian cells as observed after fractionated heat treatments

    Jorritsma, J.B.; Burgman, P.; Kampinga, H.H.; Konings, A.W.

    1986-03-01

    Possible relations between hyperthermic inactivation of alpha and beta DNA polymerase activity and hyperthermic cell killing or hyperthermic radiosensitization were investigated. Ehrlich Ascites Tumor (EAT) cells and HeLa S3 cells were treated with fractionated doses of hyperthermia. The heating schedules were chosen such that the initial heat treatment resulted in either thermotolerance or thermosensitization (step-down heating) for the second heat treatment. The results show that for DNA polymerase activity and heat radiosensitization (cell survival) no thermotolerance or thermosensitization is observed. Thus hyperthermic cell killing and DNA polymerase activity are not correlated. The correlation of hyperthermic radiosensitization and DNA polymerase activity was substantially less than observed in previous experiments with normotolerant and thermotolerant HeLa S3 cells. We conclude that alpha and beta DNA polymerase inactivation is not always the critical cellular process responsible for hyperthermic cell killing or hyperthermic radiosensitization. Other possible cellular systems that might determine these processes are discussed.

  9. Active thermal insulation for induction heating of specific metal parts

    Ulrych, B.; Kotlan, V.; Doležel, Ivo

    Plzeň : University of West Bohemia, 2011, s. 3-4. ISBN 978-80-7043-993-7. [AMTEE’11- Advanced Methods of the Theory of Electrical Engineering. Klatovy (CZ), 06.09.2011-09.09.2011] R&D Projects: GA ČR(CZ) GAP102/11/0498; GA ČR GA102/09/1305 Institutional research plan: CEZ:AV0Z20570509 Keywords : active thermal insulation * induction heating * temperature field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://amtee.zcu.cz/AMTEE/Default.aspx

  10. Chemical composition and inhibitory activity of essential oil from decaying leaves of Eucalyptus citriodora.

    Batish, Daizy R; Singh, Harminder Pal; Setia, Nidhi; Kaur, Shalinder; Kohli, Ravinder K

    2006-01-01

    A study was undertaken to explore the content and composition of volatile oil from decaying leaves of lemon-scented eucalypt (Eucalyptus citriodora Hook.) not analyzed earlier. GC and GC-MS analysis of the oil (yield 0.6%) revealed the monoterpenoid nature with citronellal (52.2%), citronellol (12.3%) and isoisopulegol (11.9%) as the major constituents. Overall, 17 components were identified that accounted for over 94% of the decaying leaf oil. Surprisingly, the decaying leaf oil contained nearly 1.8% of trans-rose oxide, which is generally absent in eucalypt essential oil. Decaying leaf oil and its major 2 components (citronellal and citronellol) inhibited the germination and root elongation of two weeds--Cassia occidentalis (broad-leaved) and Echinochloa crus-galli (grassy weed). Based on the dose-response studies, I50 values were determined for decaying leaf oil and the effect was more on germination only of broad-leaved weed (C. occidentalis), whereas that of citronellal and citronellol were on germination as well as root length of E. crus-galli (grassy weed). Based on I50 values it was observed that citronellal was more phytotoxic and germination inhibiting in nature, whereas citronellol was a more potent root inhibitor, thereby indicating a possible different mode of action. The study concludes that decaying leaf oil hold a good commercial value for exploitation as weed management agent. PMID:16610217

  11. Changes of spontaneous oscillatory activity to tonic heat pain.

    Weiwei Peng

    Full Text Available Transient painful stimuli could induce suppression of alpha oscillatory activities and enhancement of gamma oscillatory activities that also could be greatly modulated by attention. Here, we attempted to characterize changes in cortical activities during tonic heat pain perception and investigated the influence of directed/distracted attention on these responses. We collected 5-minute long continuous Electroencephalography (EEG data from 38 healthy volunteers during four conditions presented in a counterbalanced order: (A resting condition; (B innoxious-distracted condition; (C noxious-distracted condition; (D noxious-attended condition. The effects of tonic heat pain stimulation and selective attention on oscillatory activities were investigated by comparing the EEG power spectra among the four experimental conditions and assessing the relationship between spectral power difference and subjective pain intensity. The change of oscillatory activities in condition D was characterized by stable and persistent decrease of alpha oscillation power over contralateral-central electrodes and widespread increase of gamma oscillation power, which were even significantly correlated with subjective pain intensity. Since EEG responses in the alpha and gamma frequency band were affected by attention in different manners, they are likely related to different aspects of the multidimensional sensory experience of pain. The observed contralateral-central alpha suppression (conditions D vs. B and D vs. C may reflect primarily a top-down cognitive process such as attention, while the widespread gamma enhancement (conditions D vs. A may partly reflect tonic pain processing, representing the summary effects of bottom-up stimulus-related and top-down subject-driven cognitive processes.

  12. Heat Exchanger Anchors for Thermo-active Tunnels

    Mimouni, Thomas; Dupray, Fabrice; Minon, Sophie; LALOUI, Lyesse

    2013-01-01

    Shallow geothermal power represents an important energy resource for the heating and cooling of the buildings. Due to relatively low temperature levels encountered at shallow depths in the soil, between 10°C and 20°C, heat pumps are required to process the extracted heat, forming the so called ground source heat pump system. Different types of heat exchangers with the ground were developed in order to optimize the heat exchanges, from simple geothermal loops grouted in boreholes reaching dept...

  13. Enzyme activity and effect of heat treatment on some fungal diseases of postharvest tomato fruits.

    Amer, M A; El-Abd, S M; Mansour, F G F

    2013-01-01

    The activity of heat treatments for controlling tomato black mould caused by Alternaria alternata (Fr.) Keissler and grey mould caused by Botrytis cinerea Pers. Ex. Pers. wWas tested. Spore suspension of the grey mold pathogen which was exposed to hot water treatment at 58 degrees C for 6 min., failed to germinate, whereas A. alternata failed to germinate when exposed to hot water at 58 degrees C, for 8 min. Exposing discs bearing growth of any both tested fungi to hot air at 48 degrees C for 72 h caused growth suppression for the both tested pathogens. Dipping tomato fruits in hot water at 58 degrees C for 8 min or keeping in hot air for 72 h at 40 degrees C prevented decay development in non inoculated or artificially inoculated fruits with A. alternata and B. cinerea up to 12 days when stored at 24 degrees C. The high amount of polygalacturonase (PG) and pectinmethylestrase (BME) enzymes were investigated in infected fruits by the two tested pathogens as compared by healthy ones. The culture filtrate of A. alternata had the highest protease activity, white B. cinerea was the lowest. Protease activity was higher when CD liquid medium contain casein was used. PMID:25151835

  14. Comparisons of experimental beta-ray spectra important to decay heat predictions with ENSDF [Evaluated Nuclear Structure Data File] evaluations

    Graphical comparisons of recently obtained experimental beta-ray spectra with predicted beta-ray spectra based on the Evaluated Nuclear Structure Data File are exhibited for 77 fission products having masses 79--99 and 130--146 and lifetimes between 0.17 and 23650 sec. The comparisons range from very poor to excellent. For beta decay of 47 nuclides, estimates are made of ground-state transition intensities. For 14 cases the value in ENSDF gives results in very good agreement with the experimental data. 12 refs., 77 figs., 1 tab

  15. Effect of heat treatment on antimycotic activity of Sahara honey

    Moussa Ahmed

    2014-11-01

    Full Text Available Objective: To evaluate the influence of the temperature on honey colour, polyphenol contents and antimycotic capacity and to evaluate the correlation between these parameters. Methods: Sahara honey were heated up to 25, 50, 75 and 100 °C for 15, 30 and 60 min, and their colour intensity, polyphenol contents and antimycotic capacity. The Folin-Ciocalteu test was used to determine the total polyphenol contents (TPC. The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans (C. albicans and Candida glabrata (C. glabrata. Results: Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey, with the average value of 0.78 mg of gallic acid per kg of honey. The TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 mg. The minimal inhibitory concentrations before heat-treatment of Sahara honey against C. albicans and C. glabrata ranged from 3.06%-12.5% and 50% respectively. After heat-treatment the minimal inhibitory concentrations between 12.5% and 50% for C. albicans and C. glabrata, respectively. The diameters of inhibition zones of Sahara honey with 50% concentration varied from (12.67-15.00 mm by C. albicans to (14.33-15.67 mm by C. glabrata. The diameters of inhibition zones after heat-treatment at 25 and 50 °C for 15.30 and 60 min ranged from (2.00-18.67 mm by C. albicans to (8.00-16.67 mm by C. glabrata. Statistically significant relations between the TPC and the colour intensity of Sahara honey (r=0.99, P<0.05. Furthermore, the results showed that the TPC and colour is not correlated with the antimycotic capacity. Conclusions: To our knowledge this is the first report on the antimycotic capacity of Sahara honey.

  16. The Influence of Aerosol Concentration on Changes in the Volumetric Activities of Indoor Radon Short-Term Decay Products

    Diana Politova

    2011-02-01

    Full Text Available The article describes the influence of aerosol concentration on changes in the volumetric activities of indoor radon short-term decay products. The concentration of aerosol in the air, equilibrium factors and unattached fraction were measured under normal living conditions when the concentration of aerosol increases, i.e. burning a candle or frankincense in accommodations, smoke-filled accommodations, a steamy kitchen etc. It has been established that when the concentration of aerosol in the air rises, the number of free atoms of radon short-term decay products attached to aerosol particles also increases, and therefore higher volumetric activity of alpha particles is fixed. A tight positive connection of the correlation between equilibrium factor (F and aerosol particle concentration in the air of accommodations as well as a negative correlation between unattached fraction and an equilibrium factor have been determined.Article in Lithuanian

  17. Biological activity, membrane-targeting modification, and crystallization of soluble human decay accelerating factor expressed in E. coli

    White, Jennifer; Lukacik, Petra; Esser, Dirk; Steward, Michael; Giddings, Naomi; Bright, Jeremy R.; Fritchley, Sarah J.; Morgan, B. Paul; Lea, Susan M.; Smith, Geoffrey P.; Smith, Richard A. G.

    2004-01-01

    Decay-accelerating factor (DAF, CD55) is a glycophosphatidyl inositol-anchored glycoprotein that regulates the activity of C3 and C5 convertases. In addition to understanding the mechanism of complement inhibition by DAF through structural studies, there is also an interest in the possible therapeutic potential of the molecule. In this report we describe the cloning, expression in Escherichia coli, isolation and membrane-targeting modification of the four short consensus repeat domains of sol...

  18. 熔岩玻璃体核素衰变热功率的计算%Calculation of Radionuclide Decay Heat Power for Melt Glass

    包敏; 王群书; 师全林; 解峰; 王武尚

    2014-01-01

    As the temperature is a key factor affecting melt glass dissolution rate ,the decay heat power generated by radionuclides within melt glass from 10 d to 300 000 d after an underground nuclear test was calculated to assess its influence on temperature and dissolution rate .Radioactive inventories with half-life longer than 1 a ,produced by 100 kt TNT nuclear explosion published by IAEA report were used .The inventories of short-lived fission products with half-life of 1 d-1 a and accumulate yield greater than 0.1% were estimated from the inventory of 137Cs .The decay characteristics of each nuclide were analyzed .The decay energy deposited in melt glass was calculated by the mean alpha , beta and gamma energy released by radioactive decay from ENDF/B Ⅶdatabase .From the calculation ,it can be concluded that the decay heat power decays by power function ,short-lived fission products ,long-lived fission products and actinides are the main contributions to the power at 10-2 000 d , 2 000-60 000 d and after 60 000 d ,respectively .T he influence on melt glass temperature and dissolution rate is indistinctive ,especially after 1 000 d .%温度是影响熔岩玻璃体溶解速度的关键因素,为此,本文计算了核试验后10~300000d内熔岩玻璃体中核素衰变热功率,评估了核素衰变热功率对熔岩玻璃体的温度和溶解速度的影响程度。采用了国际原子能机构给出的100ktTNT当量地下核试验产生的、半衰期大于1a的放射性核素含量,利用其中裂变产物核素137Cs的含量推算累积裂变产额大于0.1%、半衰期为1d~1a的短寿命裂变产物核素的含量。分析了各核素的放射性衰变特点,采用ENDF/BⅦ库中核素衰变辐射的平均α能量、平均电子能量和平均电磁辐射能量计算各核素在熔岩玻璃体内因衰变而沉积的能量。计算结果表明:核素衰变热功率呈分段幂函数衰减;在10~2000d、2000~60000d和60000d之后的时

  19. Studies of decay heat removal by natural convection using the SONACO sodium-cooled 37-pin bundle

    Natural convection measurements in an electrically heated sodium-cooled rod bundle are being performed with the aim of contributing to a better understanding of natural convection effects in subassemblies with stagnant sodium and providing data for code validation. Measurements include temperature distributions in the bundle for different cooling configurations which simulate heat transfer to the intersubassembly gap and neighbouring subassemblies and possible thermosyphonic interaction between a subassembly and the reactor plenum above. Conditions for which stable natural convection patterns exist are identified, and results are compared with predictions of different computer codes of the porous-medium type. (author)

  20. Protein kinase A binds and activates heat shock factor 1.

    Ayesha Murshid

    Full Text Available BACKGROUND: Many inducible transcription factors are regulated through batteries of posttranslational modifications that couple their activity to inducing stimuli. We have studied such regulation of Heat Shock Factor 1 (HSF1, a key protein in control of the heat shock response, and a participant in carcinogenisis, neurological health and aging. As the mechanisms involved in the intracellular regulation of HSF1 in good health and its dysregulation in disease are still incomplete we are investigating the role of posttranslational modifications in such regulation. METHODOLOGY/PRINCIPAL FINDINGS: In a proteomic study of HSF1 binding partners, we have discovered its association with the pleiotropic protein kinase A (PKA. HSF1 binds avidly to the catalytic subunit of PKA, (PKAcα and becomes phosphorylated on a novel serine phosphorylation site within its central regulatory domain (serine 320 or S320, both in vitro and in vivo. Intracellular PKAcα levels and phosphorylation of HSF1 at S320 were both required for HSF1 to be localized to the nucleus, bind to response elements in the promoter of an HSF1 target gene (hsp70.1 and activate hsp70.1 after stress. Reduction in PKAcα levels by small hairpin RNA led to HSF1 exclusion from the nucleus, its exodus from the hsp70.1 promoter and decreased hsp70.1 transcription. Likewise, null mutation of HSF1 at S320 by alanine substitution for serine led to an HSF1 species excluded from the nucleus and deficient in hsp70.1 activation. CONCLUSIONS: These findings of PKA regulation of HSF1 through S320 phosphorylation add to our knowledge of the signaling networks converging on this factor and may contribute to elucidating its complex roles in the stress response and understanding HSF1 dysregulation in disease.

  1. Modeling activity transport in the CANDU heat transport system

    The release and transport of corrosion products from the surfaces of primary coolant system components is a serious concern for all water-cooled nuclear power plants. The consequences of high levels of corrosion product transport are twofold: a) increased corrosion product (crud) deposition on fuel cladding surfaces, leading to reduced heat transfer and the possibility of fuel failures, and b) increased production of radioactive species by neutron activation, resulting in increased out-of-core radiation fields and worker dose. In recent years, a semi-empirical activity transport model has been successfully developed to predict the deposition of radionuclides, including 60Co, 95Zr, 124Sb and fission products, around the CANDU® primary Heat Transport System (HTS), and to predict radiation fields at the steam generators and reactor face. The model links corrosion of the carbon steel outlet feeders to magnetite and radionuclide deposition on steam generator and inlet piping surfaces. This paper will describe the model development, key assumptions, required inputs, and model validation. The importance of reactor artefact characterization in the model development will be highlighted, and some key results will be presented, including oxide morphology and loadings, and radionuclide distributions within the oxide. The predictive capabilities of the model will also be described, including predictions of oxide thickness and the effects of changes in chemistry parameters such as alkalinity. While the model was developed primarily for the CANDU® HTS, the information gained during model development regarding corrosion product and radionuclide transport and deposition can also provide insights into activity transport in other water-cooled reactor systems. (author)

  2. Infrared micro-thermography of an actively heated preconcentrator device

    Furstenberg, Robert; Kendziora, C. A.; Stepnowski, Stanley V.; Mott, David R.; McGill, R. Andrew

    2008-03-01

    We report infrared micro-thermography measurements and analysis of static and transient temperature maps of an actively heated micro-fabricated preconcentrator device that incorporates a dual serpentine platinum heater trace deposited on a perforated polyimide membrane and suspended over a silicon frame. The sorbent coated perforated membrane is used to collect vapors and gases that flow through the preconcentrator. After heating, a concentrated pulse of analyte is released into the detector. Due to its small thermal mass, precise thermal management of the preconcentrator is critical to its performance. The sizes of features, the semi-transparent membrane, the need to flow air through the device, and changes in surface emissivity on a micron scale present many challenges for traditional infrared micro-thermography. We report an improved experimental test-bed. The hardware incorporates a custom-designed miniature calibration oven which, in conjunction with spatial filtering and a simple calibration algorithm, allows accurate temperature maps to be obtained. The test-bed incorporates a micro-bolometer array as the infrared imager. Instrumentation design, calibration and image processing algorithms are discussed and analyzed. The procedure does not require prior knowledge of the emissivity. We show that relatively inexpensive uncooled bolometers arrays can be used in certain radiometric applications. Heating profiles were examined with both uniform and non-uniform air flow through the device. The conclusions from this study provide critical information for optimal integration of the preconcentrator within a detection system, and in the design of the heater trace layout to achieve a more even temperature distribution across the device.

  3. Decay heat measurement of 235U in the time region from 10 to 1,000 seconds

    In order to provide a good cooling of the fuel samples during irradiation in the thermal column of the FR2 reactor, vehicles for a pneumatic transfer system were developed and constructed which keep the fuel temperature at about 10 K above the temperature of the cooling gas (N2 at 1 atm and about 300 K). For these 'rabbits' a new transport system has to be designed. Together with the mechanical system inside the vacuum vessel, which contains the calorimeter, the samples can be transfered from the irradiation position into the adiabatic jacket automatically within 2 to 3 seconds. For the measurement of the decay energy escaping the samples as γ-radiation, a MOXON-RAE-type detector was constructed. As its sensitivity increases linearly with the energy of the γ-quanta detected, this counter directly measures the energy flux of an unknown γ-spectrum. (orig./RW)

  4. HORMONAL FUNCTION OF TYROID GLAND AND MALE MUSKRAT GONADS IN THE PERIOD OF POSTNATAL ONTOGENESIS AND IN THE SEXUAL ACTIVITY DECAY PERIOD OF BAIKAL REGIONAL ECOSYSTEM

    Silkin, I.

    2011-01-01

    Basing on their own observations the authors have analyzed the dynamics of hormones concentration in thyroid gland and male muskrat gonads depending on the stage of postnatal ontogenesis and in the sexual activity decay period. As a result a number of new regularities of thyroid gland hormonal activity function in age aspect and the sexual activity decay period in muskrat males inhabiting under conditions of Baikal regional ecosystem,have been revealed.

  5. Active solar heating and cooling information user study

    Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

    1981-01-01

    The results of a series of telephone interviews with groups of users of information on active solar heating and cooling (SHAC). An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from 19 SHAC groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Manufacturers (4 groups), Distributors, Installers, Architects, Builders, Planners, Engineers (2 groups), Representatives of Utilities, Educators, Cooperative Extension Service County Agents, Building Owners/Managers, and Homeowners (2 groups). The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

  6. Sawtooth Activity in Ohmically Heated Plasma on HT-7 Tokamak

    2001-01-01

    Sawtooth activity on HT-7 tokamak has been investigated experimentally mainly by using soft x-ray diode array and magnetic probes. Their behaviors and occurrences are correlatedclosely to the discharge conditions: the electron density Ne, the electron temperature Te, the safetyfactor qa on plasma boundary and wall condition etc. When central line-averaged electron densityNe(0) is over 2.0×1013cm-3, major sawtooth activity emerges with a period of up to 6.5 ms and afluctuation amplitude of up to 2~30 % of SXR radiation signal. In some cases such as the safetyfactor between 4.2~4.7 and Zeff=3.0~6.0, a monster sawtooth activity often emerges withoutapparent deterioration of plasma confinement and without major disruption. During these events,abundant MHD phenomena are observed including partial sawtooth oscillations. In this paper, theobserved sawtooth behaviors and their dependence on the and their dependence density Ne andwall condition in ohmically heated plasma are introduced, the results are discussed and presented.

  7. 核电厂堆芯衰变热计算及影响因素分析%Calculation of Decay Heat Power and Analysis of Influence Factors for Nuclear Power Plant

    陈海英; 王韶伟; 韩静茹; 谭怡; 张春明; 朱伟

    2014-01-01

    针对压水堆核电厂,采用ORIGEN-S程序分析燃料富集度、功率水平、燃耗深度、时间步长对堆芯衰变热计算的影响程度。结果表明,采用燃耗包络法计算衰变热时,燃耗在1000~6000(MW·d)/tU之间的取值应加密,辐照时间步长对衰变热影响不大,衰变时间步长对衰变热包络值的确定具有较大影响,总衰变热随着比功率的增大而增大,随富集度变化无明显规律性。%ORIGEN-S is used to analyze the effects of fuel enrichment ,specific power ,burnup ,irradiation time steps on PWR decay heat calculation .The results show that when the burnup envelope method is used to calculate decay heat ,the burnup between 1 000 and 6 000 MWd/tU should be refined .The irradiation time step has little effect on decay heat ,while the decay time step has a greater impact on the determination of the envelope value .The total decay heat increases with the increase of the specific power .There’s no obvious rule for the decay heat when the enrichment of fuel changes .

  8. Energy-Storage Modules for Active Solar Heating and Cooling

    Parker, J. C.

    1982-01-01

    34 page report describes a melting salt hydrate that stores 12 times as much heat as rocks and other heavy materials. Energy is stored mostly as latent heat; that is, heat that can be stored and recovered without any significant change in temperature. Report also describes development, evaluation and testing of permanently sealed modules containing salt hydrate mixture.

  9. Deterministic approach of the decay heat uncertainty due to JEFF-3.1.1 nuclear data uncertainties with the CYRUS tool and the DARWIN2.3 depletion code

    The knowledge of the decay heat value and its associated uncertainty is of paramount importance for safety concerns in nuclear power plants, storage and transport facilities. The CYRUS tool has been developed in order to perform sensitivity analysis and uncertainty propagation on fuel inventories and decay heat due to the propagation of the variance and covariance data of all the nuclear data involved in the decay heat calculation (cross-sections, branching ratios, radioactive decay constants, fission yields, mean decay energies), for all kind of fuels and reactors. This tool works together with the reference depletion code DARWIN2.3 and is based on a deterministic method. In the meantime, the CEA/DEN also developed a probabilistic approach based on the URANIE uncertainty platform and the MENDEL depletion code. The purpose of this paper is to set up the bases of the deterministic method in CYRUS, to discuss the choice of the different physical correlation between the parameters, and to validate CYRUS by a numerical comparison with the probabilistic approach implemented in URANIE/MENDEL. Two preliminary applications of elementary fission bursts have been investigated: the thermal fission of 235U and the fast fission of 239Pu. All the nuclear data come from the JEFF-3.1.1 evaluation. Eventually, the comparison of the deterministic approach of CYRUS and the probabilistic approach reveals and agreement between the two methods. (author)

  10. Evaluation of the Structure Design Concept of a Combined Heat Exchanger for Decay Heat Removal System in a Sodium-cooled Fast Reactor

    In the DSFR-600 design, the internal flow path from the hot pool to the cold pool is somewhat ambiguous owing to the split flow ratio formed in a parallel path between the IHXs and DHXs. This ambiguity results in a large uncertainty in the DHX shell-side flowrate and corresponding heat transfer performance. To improve this weak point, we proposed a new design concept with a simplified flow path from the hot pool to the cold pool via a serial path passing the DHX and IHX. Hence, we developed a creative design concept of the combined IHX-DHX unit (hereafter called the CHX) and its thermal sizing and structural analysis with 3D modeling works have been carried out. This paper logically addresses the assessment results of a high temperature design and structural integrity evaluation for the CHX unit in DSFR-600. The design procedures for ensuring structural integrity regarding creep-fatigue damage conditions are briefly discussed as well. A high temperature design and structural integrity evaluation of the combined IHX-DHX unit (CHX) in DSFR-600 was performed in this study. A full 3D finite element model was implemented, and reasonable heat transfer and thermal stress analyses were made by using ABAQUS. The present design of the CHX unit was estimated to be structurally reasonable for a steady-state condition, but it was also found that some design improvement should be considered to reduce maximum stress intensity at the critical point

  11. Intercomparison of active instruments for radon and its decay products in Japan

    Intercomparison of radon and its decay products in Japan has been carried out. The number of participants in radon gas were 10 laboratories and in the decay products were 14 laboratories. The concentration level of radon during the intercomparison were 5 to 10 Bq/m3. In the intercomparison, some laboratories were regarded as standard ones and the mean of results obtained by the standard laboratories was used as a standard value. The result of the intercomparison was expressed as the ratio (relative value) between the value given by a particular laboratory and the standard value. The mean of relative value for radon gas for all the laboratories was 1.16 with a relative standard deviation of 39%. The results of the potential alpha energy were in good agreement with each other and the standard deviation of most laboratories were concentrated around 10%. In the measurements of individual concentrations of radon decay products, the standard deviations were round 30% for Po-218 and 20% for Pb-214 and Bi-214

  12. Absolute activity measurement and gamma-ray emission probability for decay of I-126

    The accurate knowledge of the gamma-ray emission probability per decay of radionuclides is important in several applications. In the case of 126 I, its importance lies mainly in fast neutron dosimetry as well as in the production of 125 I where 126 I appears as an impurity. In the present work the gamma-ray emission probabilities per decay for the 388 and 666-KeV transitions of 126 I have been measured. This radionuclide was obtained by means of the 127 I(n, 2n)126 I reaction in a fast neutron flux at the IPEN 2 MW research reactor. The methodology for the primary standardization of 126 I is described. For this purpose, two different coincidence systems were used due to the complex decay scheme of this radionuclide. The βbranch measurement was carried out in a 4 π(PC)β-γ coincidence system consisting of a proportional counter, coupled to a pair of 3'x3' Na I (Tl) crystal. The electron capture branch was measured in a X-γ coincidence system using two NaI(Tl) crystals. The gamma-ray measurements were performed in a HPGe system, previously calibrated by means of standard sources supplied by the International Atomic Energy Agency. All the uncertainties evolved were treated rigorously, by means of covariance analysis. (author)

  13. Absolute activity measurement and gamma-ray emission probability for decay of I-126

    Fonseca, K A

    1997-01-01

    The accurate knowledge of the gamma-ray emission probability per decay of radionuclides is important in several applications. In the case of sup 1 sup 2 sup 6 I, its importance lies mainly in fast neutron dosimetry as well as in the production of sup 1 sup 2 sup 5 I where sup 1 sup 2 sup 6 I appears as an impurity. In the present work the gamma-ray emission probabilities per decay for the 388 and 666-KeV transitions of sup 1 sup 2 sup 6 I have been measured. This radionuclide was obtained by means of the sup 1 sup 2 sup 7 I(n, 2n) sup 1 sup 2 sup 6 I reaction in a fast neutron flux at the IPEN 2 MW research reactor. The methodology for the primary standardization of sup 1 sup 2 sup 6 I is described. For this purpose, two different coincidence systems were used due to the complex decay scheme of this radionuclide. The beta branch measurement was carried out in a 4 pi(PC)beta-gamma coincidence system consisting of a proportional counter, coupled to a pair of 3'x3' Na I (Tl) crystal. The electron capture branch ...

  14. Microbial activity and soil organic matter decay in roadside soils polluted with petroleum hydrocarbons

    Mykhailova, Larysa; Fischer, Thomas; Iurchenko, Valentina

    2015-04-01

    It has been demonstrated previously that hydrocarbon addition to soil provokes soil organic matter priming (Zyakun et al., 2011). It has further been shown that petroleum hydrocarbons deposit to roadside soils bound to fine mineral particles and together with vehicle spray (Mykhailova et al., 2014), and that hydrocarbon concentrations decrease to safe levels within the first 15 m from the road, reaching background concentrations at 60-100 m distance (Mykhailova et al., 2013). It was the aim of this study to (I) identify the bioavailability of different petroleum hydrocarbon fractions to degradation and to (II) identify the native (i.e. pedogenic) C fraction affected by hydrocarbon-mediated soil organic matter priming during decay. To address this aim, we collected soil samples at distances from 1 to 100 m (sampling depth 15 cm) near the Traktorostroiteley avenue and the Pushkinskaya street in Kharkov, as well as near the country road M18 near Kharkov, Ukraine. The roads have been under exploitation for several decades, so microbial adaptation to enhanced hydrocarbon levels and full expression of effects could be assumed. The following C fractions were quantified using 13C-CP/MAS-NMR: Carbohydrates, Proteins, Lignin, Aliphates, Carbonyl/Carboxyl as well as black carbon according to Nelson and Baldock (2005). Petroleum hydrocarbons were determind after hexane extraction using GC-MS and divided into a light fraction (chain-length C27, Mykhailova et al., 2013). Potential soil respiration was determined every 48 h by trapping of CO2 evolving from 20 g soil in NaOH at 20 ° C and at 60% of the maximum water holding capacity and titration after a total incubation period of 4 weeks in the lab. It was found that soil respiration positively correlated with the ratio of the light fraction to the sum of medium and heavy fractions of petroleum hydrocarbons, which indicates higher biodegradation primarily of the light petroleum hydrocarbon fraction. Further, soil respiration was

  15. 不同级钚材料的衰变放热功率计算分析%Analysis of decay heat power generation for plutonium with various grades

    左应红; 朱金辉

    2016-01-01

    Background: Radioactive nuclides contained in plutonium material will continually decay and release energy, which will change the temperature of plutonium materials and the surrounding components. Purpose:This study aims to analyze the releasing heat power of various grades plutonium materials in the process of bulk storage and transportation of plutonium. Methods:According to the isotopic quality composition of various grades plutonium, the time evolutions of decay heat power of each radioactive nuclide contained in weapons grade plutonium, reactor grade plutonium, and mixed oxide grade plutonium are obtained. And the total decay heat power of various grades plutonium as a function of time is also calculated, on the basis of the analysis of radionuclide decay cascade regulation, with the energy branching ratios during decay in the physical model taken into consideration. Results:The calculation results showed that the decay heat power varied with the grades of plutonium material. For 1-kg different grades plutonium material, the maximum decay heat power quantity is released by mixed oxide grade plutonium, while the weapons grade plutonium releases the least decay heat power quantity. The heat power released by weapons grade plutonium is mainly from 239Pu, while the main heat power is from 241Pu and 238Pu for the reactor and mixed oxide grade plutonium material. The decay heat power released by 242Pu is few compared with other nuclides for the three grades of plutonium materials. Conclusion: The releasing decay heat power of plutonium materials can be calculated more accurately by considering the energy branching ratios.%钚材料中放射性核素会不断衰变并释放能量,改变钚材料及周围部件的温度。为研究不同级钚材料在其整装存储及运输过程中衰变放热功率随时间的变化规律,依据不同级钚材料的放射性核素组分,在分析核素级联衰变规律的基础上,并在物理模型中考虑衰变时的

  16. Cosmogenic-neutron activation of TeO2 and implications for neutrinoless double-beta decay experiments

    Wang, Barbara S; Scielzo, Nicholas D; Smith, Alan R; Thomas, Keenan J; Wender, Stephen A

    2015-01-01

    Flux-averaged cross sections for cosmogenic-neutron activation of natural tellurium were measured using a neutron beam containing neutrons of kinetic energies up to $\\sim$800 MeV, and having an energy spectrum similar to that of cosmic-ray neutrons at sea-level. Analysis of the radioisotopes produced reveals that 110mAg will be a dominant contributor to the cosmogenic-activation background in experiments searching for neutrinoless double-beta decay of 130Te, such as CUORE and SNO+. An estimate of the cosmogenic-activation background in the CUORE experiment has been obtained using the results of this measurement and cross-section measurements of proton activation of tellurium. Additionally, the measured cross sections in this work are also compared with results from semi-empirical cross-section calculations.

  17. Stress-Specific Activation and Repression of Heat Shock Factors 1 and 2

    Mathew, Anu; Mathur, Sameer K.; Jolly, Caroline; Fox, Susan G.; Kim, Soojin; Richard I Morimoto

    2001-01-01

    Vertebrate cells express a family of heat shock transcription factors (HSF1 to HSF4) that coordinate the inducible regulation of heat shock genes in response to diverse signals. HSF1 is potent and activated rapidly though transiently by heat shock, whereas HSF2 is a less active transcriptional regulator but can retain its DNA binding properties for extended periods. Consequently, the differential activation of HSF1 and HSF2 by various stresses may be critical for cells to survive repeated and...

  18. Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

    Shih, K. L.; Souza, K. A.

    1978-01-01

    The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

  19. The Chemistry of Self-Heating Food Products: An Activity for Classroom Engagement

    Oliver-Hoyo, Maria T.; Pinto, Gabriel; Llorens-Molina, Juan Antonio

    2009-01-01

    Two commercial self-heating food products have been used to apply chemical concepts such as stoichiometry, enthalpies of reactions and solutions, and heat transfer in a classroom activity. These products are the self-heating beverages sold in Europe and the Meals, Ready to Eat or MREs used primarily by the military in the United States. The main…

  20. Radon and its decay product activities in the magmatic area and the adjacent volcano-sedimentary Intrasudetic Basin

    D. Tchorz

    2007-06-01

    Full Text Available In the magmatic area of Sudetes covering the Karkonosze granite and adjacent volcano-sedimentary Intrasudetic Basin a study of atmospheric radon activity was performed by means of SSNTD Kodak LR-115. The study was completed by gamma spectrometric survey of eU and eTh determined by gamma activity of radon decay products 214Bi and 208Tl respectively. In the case of the western part of the Karkonosze granite area the radon decay products activity in the granitic basement was found to be as high as 343 Bq/kg for 214Bi and 496 Bq/kg for 208Tl respectively. Atmospheric radon content measured by means of Kodak LR115 track detector at the height of 1.5 m was found as high as 70 Bq/m3 in the regions, where no mining activities took place. However in the eastern part of the granitic massif in the proximity of abandoned uranium mine atmospheric radon content was found to be 6000 Bq/m3. In the case of sedimentary basin where sedimentary sequence of Carboniferous rocks has been penetrated by younger gases and fluids of volcanic origin uranium mineralization developed. The region known from its CO2 outburst during coal mining activity is characterized by good ventilation of the uranium enriched geological basement resulting in increased atmospheric radon activity being in average 72 Bq/m3. In the vicinity of coal mine tailing an increase up to 125 Bq/m3 can be observed. Seasonal variations of atmospheric radon content are influenced in agricultural areas by cyclic cultivation works (plough on soils of increased uranium content and in the case of post-industrial brownfields varying rates of radon exhalation from tailings due to different meteorological conditions.

  1. HEAT INPUT AND POST WELD HEAT TREATMENT EFFECTS ON REDUCED-ACTIVATION FERRITIC/MARTENSITIC STEEL FRICTION STIR WELDS

    Tang, Wei [ORNL; Chen, Gaoqiang [ORNL; Chen, Jian [ORNL; Yu, Xinghua [ORNL; Frederick, David Alan [ORNL; Feng, Zhili [ORNL

    2015-01-01

    Reduced-activation ferritic/martensitic (RAFM) steels are an important class of structural materials for fusion reactor internals developed in recent years because of their improved irradiation resistance. However, they can suffer from welding induced property degradations. In this paper, a solid phase joining technology friction stir welding (FSW) was adopted to join a RAFM steel Eurofer 97 and different FSW parameters/heat input were chosen to produce welds. FSW response parameters, joint microstructures and microhardness were investigated to reveal relationships among welding heat input, weld structure characterization and mechanical properties. In general, FSW heat input results in high hardness inside the stir zone mostly due to a martensitic transformation. It is possible to produce friction stir welds similar to but not with exactly the same base metal hardness when using low power input because of other hardening mechanisms. Further, post weld heat treatment (PWHT) is a very effective way to reduce FSW stir zone hardness values.

  2. A coding method for decay pathways in successive decay chain

    The decay pathways in successive decay chain were coded with binary digits. Based the coding approach and by using the E-factor method and recursion algorithm, a general purpose computer code DecayChain for calculation of the growth and decay of any member in a successive decay chain was written. The usage of decay chain code was demonstrated by the calculation of individual activities of each progenies and the total activity for the successive decay chain 228Th through 208Pb (9 members). When the relative detection efficiencies of chain members happen to meet an equation deduced in this paper the total counting rate will exponentially decrease with time with a single half-life. This conclusion was verified by the calculation performed with DecayChain for a 4-membered decay chain. (authors)

  3. Effects of heat on the biological activity of wild Cordyceps sinensis

    Pengkai Wu

    2015-01-01

    Conclusions: These results suggested that heat treatment does not adversely affect SOD or DNase activity, polysaccharide content, or cordycepin dissolution. Thus, heat treatment might be a safe processing method to extend the storage time of wild C. sinensis without compromising biological activity.

  4. 球床式高温气冷堆的余热不确定性分析%Uncertainty Analysis on Decay Heat of Pebble-bed High Temperature Gas-cooled Reactor

    贠相羽; 郑艳华; 经荥清; 李富

    2013-01-01

    反应堆在停堆后相当长时间内仍具有较高的剩余发热是核电站的重要特性,也是核电站安全分析的关键.因此,对反应堆余热及其不确定性进行分析,对于合理设计余热排出系统、研究论证燃料元件在事故后的安全特性等均具有重要意义.本工作结合德国针对球床式高温气冷堆制定的余热计算标准,介绍了球床式高温气冷堆剩余发热及其不确定性的计算方法,并结合200 MWe球床模块式高温气冷堆示范工程(HTR-PM)的初步物理设计,对长期运行在满功率平衡堆芯状态下的反应堆停堆后的余热及其不确定性进行了计算分析,为进一步的事故分析提供依据.%The large amount of decay heat in a quite long time after reactor shutdown,which is an important characteristic of the nuclear power plants,should be considered seriously during the safety analysis.Therefore,the study on the decay heat and its uncertainty analysis play an important role in the design of decay heat removal system,as well as in the safety verification of the fuel element during the accident.In referenced to the standard of Germany entitled "Decay Heat Power in Nuclear Fuels of Hightemperature Reactors with Spherical Fuel Elements" especially for pebble-bed high temperature gas-cooled reactor (HTGR),the calculation method of decay heat and its uncertainty of pebble-bed HTGR were introduced.On the basis of the preliminary physical design of Chinese 200 MWe high temperature gas-cooled reactor pebble-bed module (HTR-PM),the decay heat and its uncertainty after reactor shutdown from long-term operation at rated power were analyzed,so as to provide a basis for further accident analysis.

  5. Numerical model of heat conduction in active volcanoes induced by magmatic activity

    Atmojo, Antono Arif; Rosandi, Yudi

    2015-09-01

    We study the heat transfer mechanism of active volcanoes using the numerical thermal conduction model. A 2D model of volcano with its conduit filled by magma is considered, and acts as a constant thermal source. The temperature of the magma activity diffuses through the rock layers of the mountain to the surface. The conduction equation is solved using finite-difference method, with some adaptations to allow temperature to flow through different materials. Our model allows to simulate volcanoes having dikes, branch-pipes, and sills by constructing the domain appropriately, as well as layers with different thermal properties. Our research will show the possibility to monitor magma activity underneath a volcano by probing its surface temperature. The result of our work will be very useful for further study of volcanoes, eruption prediction, and volcanic disaster mitigation.

  6. Performance of active solar space-heating systems, 1980-1981 heating season

    Welch, K.; Kendall, P.; Pakkala, P.; Cramer, M.

    1981-01-01

    Data are provided on 32 solar heating sites in the National Solar Data Network (NSDN). Of these, comprehensive data are included for 14 sites which cover a range of system types and solar applications. A brief description of the remaining sites is included along with system problems experienced which prevented comprehensive seasonal analyses. Tables and discussions of individual site parameters such as collector areas, storage tank sizes, manufacturers, building dimensions, etc. are provided. Tables and summaries of 1980-1981 heating season data are also provided. Analysis results are presented in graphic form to highlight key summary information. Performance indices are graphed for two major groups of collectors - liquid and air. Comparative results of multiple NSDN systems' operation for the 1980-1981 heating season are summarized with discussions of specific cases and conclusions which may be drawn from the data. (LEW)

  7. Activation, Heating and Exposure Rates for Mo-99 Experiments with 25-Disk Targets

    An MCNPX model of the 25-disk target assembly inside the vacuum cube inside the shielded box was prepared. This was used to calculate heating and photon and neutron fluxes throughout the model. Production rates for photonuclear reaction products were calculated using the photon fluxes and ENDF/B-VII cross sections. Measured isomer to ground state yield ratios were used where available. Where not available the new correlation between spin deficit and isomer to ground state yield ratios presented at AccApp'11 was used. The photonuclear production rates and neutron fluxes were input to CINDER2008 for transmutation calculations. A cross section update file was used to supply (n,n') reactions missing from CINDER2008 libraries. Decay photon spectra produced by CINDER2008 were then used to calculate exposure rates using the MCNPX model. Two electron beam irradiations were evaluated. The first was for a thermal test at 15 MeV with 1300 (micro)A incident on one target end and the second was for a production test at 35 MeV with 350 (micro)A incident on both target ends (700 (micro)A total current on target). For the thermal test 1, 2, 3, 4, 5 and 6 h irradiation times were simulated, each followed by decay time steps out to 42 days. For the production test 6, 12, 18, 24, 30 and 36 h irradiation times were simulated followed by the same decay periods. For all simulations beam FWHMs in x and y were both assumed to be 6 mm. Simulations were run for Mo-100 enriched and natural Mo targets for both tests. It is planned that thermal test will be run for 4 h with natural target disks and production test will be run for 24 h with enriched target disks. Results for these two simulations only are presented in this report. Other results can be made available upon request. Post irradiation exposure rates were calculated at 30 cm distances from left, right, front and back of the following configurations: (1) Shielded box with everything in it (beam pipes, cooling pipes, vacuum cube

  8. Heat-activated Plasmonic Chemical Sensors for Harsh Environments

    Carpenter, Michael [SUNY Polytechnic Inst., Albany, NY (United States); Oh, Sang-Hyun [Univ. of Minnesota, Minneapolis, MN (United States)

    2015-12-01

    A passive plasmonics based chemical sensing system to be used in harsh operating environments was investigated and developed within this program. The initial proposed technology was based on combining technologies developed at the SUNY Polytechnic Institute Colleges of Nanoscale Science and Engineering (CNSE) and at the University of Minnesota (UM). Specifically, a passive wireless technique developed at UM was to utilize a heat-activated plasmonic design to passively harvest the thermal energy from within a combustion emission stream and convert this into a narrowly focused light source. This plasmonic device was based on a bullseye design patterned into a gold film using focused ion beam methods (FIB). Critical to the design was the use of thermal stabilizing under and overlayers surrounding the gold film. These stabilizing layers were based on both atomic layer deposited films as well as metal laminate layers developed by United Technologies Aerospace Systems (UTAS). While the bullseye design was never able to be thermally stabilized for operating temperatures of 500oC or higher, an alternative energy harvesting design was developed by CNSE within this program. With this new development, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The method was further improved by patterning rods which harvested energy in the near infrared, which led to a factor of 10 decrease in data acquisition times as well as demonstrated selectivity with a reduced wavelength data set. The combination of a plasmonic-based energy harvesting

  9. Initiation-mediated mRNA decay in yeast affects heat-shock mRNAs, and works through decapping and 5′-to-3′ hydrolysis

    Heikkinen, Heather L.; Llewellyn, Sara A.; Barnes, Christine A.

    2003-01-01

    The degradation of mRNA in the yeast Saccharomyces cerevisiae takes place through several related pathways. In the most general mRNA-decay pathway, that of poly(A)-dependent decay, the normal shortening of the poly(A) tail on an mRNA molecule by deadenylation triggers mRNA decapping by the enzyme Dcp1p, followed by exonucleolytic digestion by Xrn1p. A specialized mRNA-decay pathway, termed nonsense-mediated decay, comes into play for mRNAs that contain an early nonsense codon. This pathway op...

  10. Visible light active photocatalyst from recycled disposable heating pads

    Lee, Meng-Chien; Wang, Chun-Yu; Chen, Che-Chin; Wang, Chih-Ming; Hsiao, Ta-Chih; Tsai, Din Ping

    2016-01-01

    Alpha-Fe2O3 (α-Fe2O3) is cheap and abundant and has potential to be a highly efficient photocatalyst for water splitting. According to the report, there are a huge amount of disposable heating pads being created every year, and the pads are used one time then thrown away. We found that the main product of used heating pads is α-Fe2O3. Here, we collect and purify the α-Fe2O3 powder in the used heating pads using low power consumption processes. It is shown that the recycled heating pads can be used as a cost-effective photocatalyst for H2 energy and for decomposition of organic pollutants as well. Additionally, the plasmonic enhanced photocatalysis reaction of α-Fe2O3 is also investigated. It is found that H2 evolution rate can be enhanced 15% using α-Fe2O3 nanoparticles coated with a thin Au layer. The degradation of methylene blue can also enhance 12% compared to photocatalyst α-Fe2O3 nanoparticles coated without Au layer.

  11. Beta and gamma decay heat measurements between 0.1s--50,000s for neutron fission of 235U, 238U and 239Pu. Final report, June 1, 1992--December 31, 1996

    This is a final reporting on the composition of separate beta and gamma decay heat measurements following neutron fission of 235U and 238U and 239Pu and on cumulative and independent yield measurements of fission products of 235U and 238U. What made these studies unique was the very short time of 0.1 s after fission that could be achieved by incorporating the helium jet and tape transport system as the technique for transporting fission fragments from the neutron environment of the fission chamber to the low-background environment of the counting area. This capability allowed for the first time decay heat measurements to extend nearly two decades lower on the logarithmic delay time scale, a region where no comprehensive aggregate decay heat measurements had extended to. This short delay time capability also allowed the measurement of individual fission products with half lives as short as 0.2s. The purpose of such studies was to provide tests both at the aggregate level and at the individual nuclide level of the nation's evaluated nuclear data file associated with fission, ENDF/B-VI. The results of these tests are in general quite encouraging indicating this data base generally predicts correctly the aggregate beta and aggregate gamma decay heat as a function of delay time for 235U, 238U and 239Pu. Agreement with the measured individual nuclide cumulative and independent yields for fission products of 235U and 238U was also quite good although the present measurements suggest needed improvements in several individual cases

  12. Effects of single-dose irradiation on tumor blood flow studied by 15O decay after photon activation in situ

    A noninvasive technique employing photon activation of tissue oxygen in situ and detection of subsequent 15O positron decay was used to study the effects of single-dose 60Co irradiation on capillary blood flow in transplanted rat rhabdomyosarcomas. Tumor blood flow was measured before irradiation with 16.5, 38.5, or 60.5 Gy and at sever al intervals afterward (0-72 hr). Pre-irradiation values of volume-averaged blood flow in the tumor ranged from 7 to 44 ml/min/100 g. Several hours after irradiation, blood flow fell by up to 50% for 60.5 Gy and up to 35% for 16.5 Gy. However, 24 hours after irradiation, tumor blood flow had recovered completely in the 16.5-Gy group and substantially in the others. For smaller doses such as the fractions typically employed in radiotherapy, no changes in tumor blood flow were observed

  13. Effects of single-dose irradiation in tumor blood flow studied by 15O decay after proton activation in situ.

    Emami, B; Ten Haken, R K; Nussbaum, G H; Hughes, W L

    1981-10-01

    A noninvasive technique employing photon activation of tissue oxygen in situ and detection of subsequent 15O positron decay was used to study the effects of single-dose 60Co irradiation on capillary blood flow in transplanted rat rhabdomyosarcomas. Tumor blood flow was measured before irradiation with 16.5, 38.5, or 60.5 Gy and at several intervals afterward (0-72 hr.). Pre-irradiation values of volume-averaged blood flow in the tumor ranged from 7 to 44 ml/min./100 g. Several hours after irradiation, blood flow fell by up to 50% for 60.5 Gy and up to 35% for 16.5 Gy. However, 24 hours after irradiation, tumor blood flow had recovered completely in the 16.5-Gy group and substantially in the others. For smaller doses such as the fractions typically employed in radiotherapy, no changes in tumor blood flow were observed. PMID:7291527

  14. Effects of single-dose irradiation in tumor blood flow studied by 15O decay after proton activation in situ

    A noninvasive technique employing photon activation of tissue oxygen in situ and detection of subsequent 15O positron decay was used to study the effects of single-dose 60Co irradiation on capillary blood flow in transplanted rat rhabdomyosarcomas. Tumor blood flow was measured before irradiation with 16.5, 38.5, or 60.5 Gy and at several intervals afterward (0-72 hr.). Pre-irradiation values of volume-averaged blood flow in the tumor ranged from 7 to 44 ml/min./100 g. Several hours after irradiation, blood flow fell by up to 50% for 60.5 Gy and up to 35% for 16.5 Gy. However, 24 hours after irradiation, tumor blood flow had recovered completely in the 16.5-Gy group and substantially in the others. For smaller doses such as the fractions typically employed in radiotherapy, no changes in tumor blood flow were observed

  15. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  16. Comparison of the Results of the Whole Core Decay Power Using the ORIGEN Code and ANS-1979 for the Uljin Unit 6

    When a detailed tracking of the nuclide is not required-, i.e., only the whole core decay heat information is required, then the RN package is not activated and the DCH package is solely used, whereas both the RN and DCH packages are used when we need a fission product transport simulation and location information. For DCH only mode, there are four options to calculate the whole core decay heat calculation for the time after a shut-down. The first is using a summation of the decay heat data from ORIGEN-based fission product inventories for the representative BWRs and PWRs, which are scaled if necessary. The second is using the ANS-1979 standard for the decay heat power. The third is using a user-specified tabular function of the whole-core decay as a function of time. The fourth is using a user-specified control function to define the decay heat. In this research, for option 2, the ANS-1979 standard for the whole core decay heat calculation is compared with the result of the ORIGEN calculation for Uljin Unit 6 after arranging the ORIGEN result based on the mass, radioactivity, and decay heat for the elements and nuclides. The MELCOR code is currently using the ANS-1979 standard, the lasted version for decay heat in ANS standards is not mainly dealt with in this research. The goal of the examination is to find the necessity of changing old standard for the enhancement of the accuracy. The ANS-1979 is an old standard about decay heat, thus recent standards which are ANSI/ANS-5.1-1994 and ANSI/ANS-5.1-2005 should be investigated in the long term research. This research has certain drawback in that the mere multiplication of the number of assemblies is done for the whole core decay heat calculation in the arrangement of the ORIGEN result

  17. Active solar heating system performance and data review

    Bates, J.; Bertarelli, L.; Schmidt, G.

    1999-07-01

    This report summarises the results of a study investigating the performance and costs of solar heating systems in Europe, and their relevance to systems in the UK. Details are given of the identification and review of the available data, the collection of information on UK and overseas systems, and the assessment and analysis of the data. Appendices give a lists of the monitored parameters, European contacts, data sources, the questionnaire for gathering information, and a printout of the data files. (uk)

  18. Expression profile of heat shock response factors during hookworm larval activation and parasitic development.

    Gelmedin, Verena; Delaney, Angela; Jennelle, Lucas; Hawdon, John M

    2015-07-01

    When organisms are exposed to an increase in temperature, they undergo a heat shock response (HSR) regulated by the transcription factor heat shock factor 1 (HSF-1). The heat shock response includes the rapid changes in gene expression initiated by binding of HSF-1 to response elements in the promoters of heat shock genes. Heat shock proteins function as molecular chaperones to protect proteins during periods of elevated temperature and other stress. During infection, hookworm infective third stage larvae (L3) undergo a temperature shift from ambient to host temperature. This increased temperature is required for the resumption of feeding and activation of L3, but whether this increase initiates a heat shock response is unknown. To investigate the role of the heat shock in hookworm L3 activation and parasitic development, we identified and characterized the expression profile of several components of the heat shock response in the hookworm Ancylostoma caninum. We cloned DNAs encoding an hsp70 family member (Aca-hsp-1) and an hsp90 family member (Aca-daf-21). Exposure to a heat shock of 42°C for one hour caused significant up-regulation of both genes, which slowly returned to near baseline levels following one hour attenuation at 22°C. Neither gene was up-regulated in response to host temperature (37°C). Conversely, levels of hsf-1 remained unchanged during heat shock, but increased in response to incubation at 37°C. During activation, both hsp-1 and daf-21 are down regulated early, although daf-21 levels increase significantly in non-activated control larvae after 12h, and slightly in activated larvae by 24h incubation. The heat shock response modulators celastrol and KNK437 were tested for their effects on gene expression during heat shock and activation. Pre-incubation with celastrol, an HSP90 inhibitor that promotes heat shock gene expression, slightly up-regulated expression of both hsp-1 and daf-21 during heat shock. KNK437, an inhibitor of heat shock

  19. A semi-analytical model for heat and mass transfer in geothermal reservoirs to estimate fracture surface-are-to-volume ratios and thermal breakthrough using thermally-decaying and diffusing tracers

    Reimus, Paul W [Los Alamos National Laboratory

    2010-12-08

    A semi-analytical model was developed to conduct rapid scoping calculations of responses of thermally degrading and diffusing tracers in multi-well tracer tests in enhanced geothermal systems (EGS). The model is based on an existing Laplace transform inversion model for solute transport in dual-porosity media. The heat- and mass-transfer calculations are decoupled and conducted sequentially, taking advantage of the fact that heat transfer between fractures and the rock matrix is much more rapid than mass transfer and therefore mass transfer will effectively occur in a locally isothermal system (although the system will be nonisothermal along fracture flow pathways, which is accounted for by discretizing the flow pathways into multiple segments that have different temperature histories). The model takes advantage of the analogies between heat and mass transfer, solving the same governing equations with k{sub m}/({rho}C{sub p}){sub w} being substituted for {phi}D{sub m} in the equation for fracture transport and k{sub m}/({rho}C{sub p}){sub m} being subsituted for D{sub m} in the equation for matrix transport; where k = thermal conductivity (cal/cm-s-K), {rho} = density (g/cm{sup 3}), C{sub p} = heat capacity (at constant pressure) (cal/g-K), {phi} = matrix porosity, and D = tracer diffusion coefficient (cm{sup 2}/s), with the subscripts w and m referring to water and matrix, respectively. A significant advantage of the model is that it executes in a fraction of second on a single-CPU personal computer, making it very amenable for parameter estimation algorithms that involve repeated runs to find global minima. The combined thermal-mass transport model was used to evaluate the ability to estimate when thermal breakthrough would occur in a multi-well EGS configuration using thermally degrading tracers. Calculations were conducted to evaluate the range of values of Arrhenius parameters, A and E{sub {alpha}} (pre-exponential factor, 1/s, and activation energy, cal

  20. Status report on preliminary design activities for solar heating and cooling systems

    1978-05-01

    Information presented provides status and progress on the development of solar heating and cooling systems. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities as part of the contract requirements.

  1. Contribution to the measurement of absolute activity of electron capture decaying nuclides. Determination of the fluorescence yield of some elements

    The object of this work is the study of techniques of measurement of the absolute activity of electron capture nuclides. Two methods have been specially studied. Determination of the number of X rays emitted from the K shell due to the reorganization of atomic electrons following electron capture. This measurement was made with a high pressure (5 kg/cm2) 4π proportional counter. The absorption in the source and the backing were also studied. To determine the absolute activity it is necessary to know the fluorescence yield and the different capture probabilities PL and PK. When the electron capture is followed by γ emission (within the resolution time of the coincidence circuit) the activity was determined through the X-γ coincidence method. In such a case it is not necessary to know the fluorescence yield and the capture probabilities. Various corrections - dead time, chance coincidences - were also studied. This method minimizes the decay scheme corrections. By applying these two methods to the following nuclides: Cr51, Mn54 and Zn65, the corresponding fluorescence yields have been determined: vanadium ωK = 0.191 ±0.002, chromium ωK = 0.262 ± 0.002 and copper ωK = 0.390 ± 0.004. (author)

  2. Heating and active control of profiles and transport by IBW in the HT-7 tokamak

    Significant progress on Ion Bernstein Wave (IBW) heating and control of profiles has been obtained in HT-7. Both on-axis and off-axis electron heating with global peaked and local steep electron pressure profiles were realized if the position of the resonant layer was selected to be plasma far from the plasma edge region. Reduction of electron heat transport has been observed from sawtooth heat pulse propagation. Improvement of both particle and energy confinement was slight in the on-axis and considerable in the off-axis heating cases. The improved confinement in off-axis heating mode may be due to the extension of the high performance plasma volume caused by IBW. These studies demonstrate that IBWs are potentially a tool for active control of plasma profiles and transport. (author)

  3. Role of heat shock factor-1 activation in the doxorubicin-induced heart failure in mice

    Vedam, Kaushik; Nishijima, Yoshinori; Druhan, Lawrence J.; Khan, Mahmood; Moldovan, Nicanor I.; Zweier, Jay L.; Ilangovan, Govindasamy

    2010-01-01

    Treating cancer patients with chemotherapeutics, such as doxorubicin (Dox), cause dilated cardiomyopathy and congestive heart failure because of oxidative stress. On the other hand, heat shock factor-1 (HSF-1), a transcription factor for heat shock proteins (Hsps), is also known to be activated in response to oxidative stress. However, the possible role of HSF-1 activation and the resultant Hsp25 in chemotherapeutic-induced heart failure has not been investigated. Using HSF-1 wild-type (HSF-1...

  4. Measurement of the absolute activity of alpha or beta emitters by measuring product nuclei (daughter) activity increase or by studing its radioactive decay

    A new method for determining absolute activity of alpha or beta emitters by measuring daughter product radioactive decay is presented. The separation method of UX from hexahydrated uranyl nitrate UO2(NO3)2 6H2O based on its dissolution in ethyl ether is described and the accuracy of this method is shown. The factors which accuate on total efficiency of a Geiger Mueller detector for beta particles are determined. The possibility to determine the mass of precursor element by daughter nuclei activity is shown. The results are compared with the one obtained by direct measurement of the mass (or number of atoms) of precursor radioactive substance and with theoretical values calculated for isotopes in secular equilibrium. (Author)

  5. Active control of divertor heat and particle fluxes in EAST towards advanced steady state operations

    Significant progress has been made in EAST towards advanced steady state operations by active control of divertor heat and particle fluxes. Many innovative techniques have been developed to mitigate transient ELM and stationary heat fluxes on the divertor target plates. It has been found that lower hybrid current drive (LHCD) can lead to edge plasma ergodization, striation of the stationary heat flux and lower ELM transient heat and particle fluxes. With multi-pulse supersonic molecular beam injection (SMBI) to quantitatively regulate the divertor particle flux, the divertor power footprint pattern can be actively modified. H-modes have been extended over 30 s in EAST with the divertor peak heat flux and the target temperature being controlled well below 2 MW/m2 and 250 °C, respectively, by integrating these new methods, coupled with advanced lithium wall conditioning and internal divertor pumping, along with an edge coherent mode to provide continuous particle and power exhaust

  6. Active control of divertor heat and particle fluxes in EAST towards advanced steady state operations

    Wang, L., E-mail: lwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Dalian University of Technology, Dalian 116024 (China); Guo, H.Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); General Atomics, P. O. Box 85608, San Diego, CA 92186 (United States); Li, J.; Wan, B.N.; Gong, X.Z.; Zhang, X.D.; Hu, J.S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Liang, Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Association EURATOM-FZJ, D-52425 Jülich (Germany); Xu, G.S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zou, X.L. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Loarte, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Maingi, R.; Menard, J.E. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Luo, G.N.; Gao, X.; Hu, L.Q.; Gan, K.F.; Liu, S.C.; Wang, H.Q.; Chen, R. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); and others

    2015-08-15

    Significant progress has been made in EAST towards advanced steady state operations by active control of divertor heat and particle fluxes. Many innovative techniques have been developed to mitigate transient ELM and stationary heat fluxes on the divertor target plates. It has been found that lower hybrid current drive (LHCD) can lead to edge plasma ergodization, striation of the stationary heat flux and lower ELM transient heat and particle fluxes. With multi-pulse supersonic molecular beam injection (SMBI) to quantitatively regulate the divertor particle flux, the divertor power footprint pattern can be actively modified. H-modes have been extended over 30 s in EAST with the divertor peak heat flux and the target temperature being controlled well below 2 MW/m{sup 2} and 250 °C, respectively, by integrating these new methods, coupled with advanced lithium wall conditioning and internal divertor pumping, along with an edge coherent mode to provide continuous particle and power exhaust.

  7. Antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.

    Lixandru, Brînduşa-Elena; Drăcea, Nicoleta Olguţa; Dragomirescu, Cristiana Cerasella; Drăgulescu, Elena Carmina; Coldea, Ileana Luminiţa; Anton, Liliana; Dobre, Elena; Rovinaru, Camelia; Codiţă, Irina

    2010-01-01

    The currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. The purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the National Institute of Research-Development for Chemistry and Petrochemistry, Bucharest to be used for the further development of food packaging technology, based on their antibacterial and antifungal activity. The essential oils extracted from thyme (Thymus vulgaris L.), basil (Ocimum basilicum L.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), fennel (Foeniculum vulgare L.), spearmint (Mentha spicata L.) and carraway (Carum carvi L.) were investigated for their antimicrobial activity against eleven different bacterial and three fungal strains belonging to species reported to be involved in food poisoning and/or food decay: S. aureus ATCC 25923, S. aureus ATCC 6538, S. aureus ATCC 25913, E. coli ATCC 25922, E. coli ATCC 35218, Salmonella enterica serovar Enteritidis Cantacuzino Institute Culture Collection (CICC) 10878, Listeria monocytogenes ATCC 19112, Bacillus cereus CIP 5127, Bacillus cereus ATCC 11778, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, Penicillium spp. CICC 251 and two E. coli and Salmonella enterica serovar Enteritidis clinical isolates. The majority of the tested essential oils exibited considerable inhibitory capacity against all the organisms tested, as supported by growth inhibition zone diameters, MICs and MBC's. Thyme, coriander and basil oils proved the best antibacterial activity, while thyme and spearmint oils better inhibited the fungal species. PMID:21462837

  8. 池式研究堆衰变热计算与实验研究%Research on Decay Heat Calculation and Measurement for Pool-Type Research Reactor

    黄洪文; 刘汉刚; 米向秒; 钱达志; 杨晓斌; 黄文; 张之华

    2012-01-01

    The heat-measurement method is adopted to measure the decay heat of a nuclear reactor during 45.0 hours after the rated power operation of 75.0 hours; an empirical formula is fitted according to the experimental data. Several calculation empirical formulas used to calculate the residual power of a nuclear reactor and comparison with the test result indicated that the heat-measurement method could be used to measure the decay heat of a reactor, and the data is conformed to the standard of EJ/T 745.%采用量热法测量反应堆额定功率运行75.0 h停堆后45 h内的衰变热功率,拟合出归一化衰变热功率的经验关系式.与反应堆衰变热几种半经验公式和标准对比结果表明,实验结果在经验公式计算值范围内,并与EJ/T 745标准预测值符合较好.

  9. Tau decays

    The most recent experimental results of τ physics are reviewed. The covered topics include precision measurements of semihadronic τ decay and their impact on tau branching ratio budget, the current status of the tau consistency test, a determination of Michel parameters and τ neutrino helicity, and upper limits on lepton-number violating τ decays. (orig.)

  10. Effects of heat on the biological activity of wild Cordyceps sinensis

    Pengkai Wu; Zhi Tao; Huafeng Liu; Guixiang Jiang; Changhua Ma; Chunmei Wang; Di Geng

    2015-01-01

    Background: Current methods of extending the storage time of wild Cordyceps sinensis adversely affect the nutritive and medicinal value of the product. Thus, this study was designed to investigate the effects of heat treatment, a relatively safe storage extension method, on the biological activity of wild C. sinensis. Methods: Samples were heated to 60, 80, or 100°C for 15, 30, or 60 minutes. SOD activity in wild C. sinensis before and after heating was assayed using a standard colorimetri...

  11. Innovative two-pipe active chilled beam system for simultaneous heating and cooling of office buildings

    Maccarini, Alessandro; Afshari, Alireza; Bergsøe, Niels Christian;

    2014-01-01

    The aim of this paper was to investigate the energy savings potential of an innovative two-pipe system in an active chilled beam application for heating and cooling of office buildings. The characteristic of the system is its ability to provide simultaneous heating and cooling by transferring...... heating, cooling and ventilation loads were calculated by the program and an annual energy consumption evaluation of the system was made. Simulation results showed that the innovative two-pipe active chilled beam system used approximately 5% less energy than a conventional four-pipe system....

  12. Decay power: a comprehensive experimental validation

    An experimental decay power measurement program combined with the code calculations performed in this studies provides a unique check of the calculational method and nuclear databases associated with the prediction of decay power for the set of material samples analysed. 74 material samples from Z=9 to 83 (with exception for Z=10, 18, 36, 43, 54, 61, 80, 84-88) and 4 alloys (SS-304, SS-316, NiCr, Inc-600) have been irradiated with 14 MeV neutrons using the Fusion Neutron Source (FNS) facility at the Japan Atomic Energy Agency. Most samples were irradiated for times up to 7 hours and the decay power was measured for cooling times up to 1 year. Using the highly sensitive Whole Energy Absorption Spectrometer (WEAS) method, both β and γ rays decay energies were measured at selected cooling times as early as a few tens of seconds after the irradiation ended. The European Activation System EASY-2007 has been used to perform this validation exercise. 3 cross-section databases have been accessed using the 2007 version of the FISPACT code. The group-wise libraries used in the calculational scheme correspond to the 175 vitamin-J group structure collapsed using a flat micro flux weighing function. The results of this validation exercise indicate that the calculational methods and nuclear databases, with some notable exceptions, generally allow predictions with quantifiable margins of the decay power of the tested materials. It tests the specific production pathways and at the same time the decay data associated with the nuclides that dominate the decay heat

  13. Monster Sawtooth Activity in Ohmically Heated HT-7 Plasma

    胡立群; 石跃江; 刘胜侠

    2001-01-01

    Experimental properties of monster sawtooth activities in ohmic HT-7 plasma are presented in this paper. The monster sawtooth activities belong to global fluctuations and are characterized with a series of large core collapses on SXR intensity traces with a long period, a large amplitude fluctuation and a large inversion radius. However, they emerge without apparent deterioration of plasma confinement and without major plasma disruption. During the events,long partial sawtooth collapses and abundant MHD phenomena are also observed.

  14. BRF1 Protein Turnover and mRNA Decay Activity Are Regulated by Protein Kinase B at the Same Phosphorylation Sites▿

    Benjamin, Don; Schmidlin, Martin; Min, Lu; Gross, Brigitte; Moroni, Christoph

    2006-01-01

    BRF1 posttranscriptionally regulates mRNA levels by targeting ARE-bearing transcripts to the decay machinery. We previously showed that protein kinase B (PKB) phosphorylates BRF1 at Ser92, resulting in binding to 14-3-3 and impairment of mRNA decay activity. Here we identify an additional regulatory site at Ser203 that cooperates in vivo with Ser92. In vitro kinase labeling and wortmannin sensitivity indicate that Ser203 phosphorylation is also performed by PKB. Mutation of both serines to al...

  15. Effects of Different Catalytic Activation Techniques on the Thermal Performance of Flip Chip Heat Spreader

    This paper presents the effects of two different catalytic activation techniques on the thermal performance of flip chip heat spreaders. Electroless nickel plating is used as a plating technique as it can form a uniform thickness of nickel layer onto the copper substrate. Catalytic activation process needs to be done first to deposit some nickel atom onto copper substrate, so that the deposited nickel is able to catalyze the following reduction process. The two activation techniques investigated are galvanic initiation and thin nickel-copper strike. High temperature storage tests were ran to investigate the extent of intermetallic diffusion between the nickel and copper layers. Thermal diffusivity of these heat spreaders was studied using the Nano-flash apparatus. The results obtained showed that heat spreaders processed with thin nickel copper strike have lower thermal diffusivities (35-65 mm2 s-1) compared to those heat spreaders processed with galvanic-initiation (60-85 mm2 s-1). It is also discovered that the nickel-copper intermetallic layers of these heat spreaders grew thicker from 0.2 μm at initial time until 0.55 μm after high temperature storage of 168 hours. Nickel-copper intermetallic layers have lower thermal conductivity compared to pure copper, this further degrading the thermal diffusivity of these heat spreaders. As a conclusion, the galvanic initiation technique provides better thermal performance for heat spreaders used in semiconductor package. (author)

  16. Ethnic differences in thermoregulatory responses during resting, passive and active heating: application of Werner's adaptation model.

    Lee, Joo-Young; Wakabayashi, Hitoshi; Wijayanto, Titis; Hashiguchi, Nobuko; Saat, Mohamed; Tochihara, Yutaka

    2011-12-01

    For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives' homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder's law of initial value and Werner's process and controller adaptation model. PMID:21437607

  17. Thermo Active Building Systems – Using Building Mass To Heat and Cool

    Olesen, Bjarne W.

    2014-01-01

    Using the thermal storage capacity of the concrete slabs between each floor in multistory buildings to heat or cool is a trend that began in the early 1990s in Switzerland.1,2 Pipes carrying water for heating and cooling are embedded in the center of the concrete slab. In central Europe (Germany...... multistory buildings. By activating the building mass, there is a direct heating-cooling effect. Also, because of the thermal mass, the peak load will be reduced and some of the cooling load will be transferred beyond the time of occupancy. Because these systems for cooling operate at water temperatures...... close to room temperature, they increase the efficiency of heat pumps, ground heat exchangers and other systems using renewable energy sources....

  18. A novel heat flux study of a geothermally active lake - Lake Rotomahana, New Zealand

    Tivey, Maurice A.; de Ronde, Cornel E. J.; Tontini, Fabio Caratori; Walker, Sharon L.; Fornari, Daniel J.

    2016-03-01

    A new technique for measuring conductive heat flux in a lake was adapted from the marine environment to allow for multiple measurements to be made in areas where bottom sediment cover is sparse, or even absent. This thermal blanket technique, pioneered in the deep ocean for use in volcanic mid-ocean rift environments, was recently used in the geothermally active Lake Rotomahana, New Zealand. Heat flow from the lake floor propagates into the 0.5 m diameter blanket and establishes a thermal gradient across the known blanket thickness and thereby provides an estimate of the conductive heat flux of the underlying terrain. This approach allows conductive heat flux to be measured over a spatially dense set of stations in a relatively short period of time. We used 10 blankets and deployed them for 1 day each to complete 110 stations over an 11-day program in the 6 × 3 km lake. Results show that Lake Rotomahana has a total conductive heat flux of about 47 MW averaging 6 W/m2 over the geothermally active lake. The western half of the lake has two main areas of high heat flux; 1) a high heat flux area averaging 21.3 W/m2 along the western shoreline, which is likely the location of the pre-existing geothermal system that fed the famous Pink Terraces, mostly destroyed during the 1886 eruption 2) a region southwest of Patiti Island with a heat flux averaging 13.1 W/m2 that appears to be related to the explosive rift that formed the lake in the 1886 Tarawera eruption. A small rise in bottom water temperature over the survey period of 0.01 °C/day suggests the total thermal output of the lake is ~ 112-132 MW and when compared to the conductive heat output suggests that 18-42% of the total thermal energy is by conductive heat transfer.

  19. Effects of calmodulin on DNA-binding activity of heat shock transcription factor in vitro

    2003-01-01

    The DNA-binding activity of heat shock transcription factor (HSF) was induced by heat shock (HS) of a whole cell extract. Addition of antiserum, specific to CaM, to a whole cell extract reduced bind of the HSF to the heat shock element (HSE) with maize, and the re-addition of CaM to the sample restored the activity of the HSF for binding to HSE. In addition, DNA-binding activity of the HSF was also induced by directly adding CaM to a whole cell extract at non-HS temperature with maize. Similar results were obtained with wheat and tomato. Our observations provide the first example of the involvement of CaM in regulation of the DNA-binding activity of the HSF.

  20. Determination of antigenicity by radioimmunoassay and of trypsin inhibitory activities in heat or enzyme denatured ovomucoid

    The effects of heat treatment and enzymic digestion on the antigenic reactivity of ovomucoid were studied. This reactivity was mainly examined by a solid phase competitive radioimmunoassay. The trypsin inhibitory activity was also measured to elucidate its relationship to the antigenic reactivity. The antigenic reactivity and trypsin inhibitory activity diminished in parallel with increase of heating time. However, enzymic digestion caused a more rapid decrease in antigenic reactivity than in trypsin inhibitory activity. From these results, it is suggested that the structure of the antigenic determinants is destroyed in a similar manner to that of the trypsin inhibitory active site when ovomucoid is heated, while the former structure is destroyed more easily than the latter by enzymic digestion

  1. Proton Decay

    Raby, Stuart

    2002-01-01

    We discuss the status of supersymmetric grand unified theories [SUSY GUTs] with regards to the observation of proton decay. In this talk we focus on SUSY GUTs in 4 dimensions. We outline the major theoretical uncertainties present in the calculation of the proton lifetime and then present our best estimate of an absolute upper bound on the predicted proton lifetime. Towards the end, we consider some new results in higher dimensional GUTs and the ramifications for proton decay.

  2. A JOULE-HEATED MELTER TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

    KELLY SE

    2011-04-07

    This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of joule-heated ceramic lined melters and their application to Hanford's low-activity waste.

  3. A Joule-Heated Melter Technology For The Treatment And Immobilization Of Low-Activity Waste

    This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of joule-heated ceramic lined melters and their application to Hanford's low-activity waste.

  4. Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor

    Xingtuan Yang; Yanfei Sun; Huaiming Ju; Shengyao Jiang

    2014-01-01

    After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was ca...

  5. How a retrotransposon exploits the plant's heat stress response for its activation.

    Vladimir V Cavrak

    2014-01-01

    Full Text Available Retrotransposons are major components of plant and animal genomes. They amplify by reverse transcription and reintegration into the host genome but their activity is usually epigenetically silenced. In plants, genomic copies of retrotransposons are typically associated with repressive chromatin modifications installed and maintained by RNA-directed DNA methylation. To escape this tight control, retrotransposons employ various strategies to avoid epigenetic silencing. Here we describe the mechanism developed by ONSEN, an LTR-copia type retrotransposon in Arabidopsis thaliana. ONSEN has acquired a heat-responsive element recognized by plant-derived heat stress defense factors, resulting in transcription and production of full length extrachromosomal DNA under elevated temperatures. Further, the ONSEN promoter is free of CG and CHG sites, and the reduction of DNA methylation at the CHH sites is not sufficient to activate the element. Since dividing cells have a more pronounced heat response, the extrachromosomal ONSEN DNA, capable of reintegrating into the genome, accumulates preferentially in the meristematic tissue of the shoot. The recruitment of a major plant heat shock transcription factor in periods of heat stress exploits the plant's heat stress response to achieve the transposon's activation, making it impossible for the host to respond appropriately to stress without losing control over the invader.

  6. Effects of microwave heating on porous structure of regenerated powdered activated carbon used in xylose.

    Li, Wei; Wang, Xinying; Peng, Jinhui

    2014-01-01

    The regeneration of spent powdered activated carbons used in xylose decolourization by microwave heating was investigated. Effects of microwave power and microwave heating time on the adsorption capacity of regenerated activated carbons were evaluated. The optimum conditions obtained are as follows: microwave power 800W; microwave heating time 30min. Regenerated activated carbon in this work has high adsorption capacities for the amount of methylene blue of 16 cm3/0.1 g and the iodine number of 1000.06mg/g. The specific surface areas of fresh commercial activated carbon, spent carbon and regenerated activated carbon were calculated according to the Brunauer, Emmett and Teller method, and the pore-size distributions of these carbons were characterized by non-local density functional theory (NLDFT). The results show that the specific surface area and the total pore volume of regenerated activated carbon are 1064 m2/g and 1.181 mL/g, respectively, indicating the feasibility of regeneration of spent powdered activated carbon used in xylose decolourization by microwave heating. The results of surface fractal dimensions also confirm the results of isotherms and NLDFT. PMID:24645431

  7. A correction factor to f-chart predictions of active solar fraction in active-passive heating systems

    Evans, B. L.; Beckman, W. A.; Duffie, J. A.; Mitchell, J. W.; Klein, S. A.

    1983-11-01

    The extent to which a passive system degrades the performance of an active solar space heating system was investigated, and a correction factor to account for these interactions was developed. The transient system simulation program TRNSYS is used to simulate the hour-by-hour performance of combined active-passive (hybrid) space heating systems in order to compare the active system performance with simplified design method predictions. The TRNSYS simulations were compared to results obtained using the simplified design calculations of the f-Chart method. Comparisons of TRNSYS and f-Chart were used to establish the accuracy of the f-Charts for active systems. A correlation was then developed to correct the monthly loads input into the f-Chart method to account for controller deadbands in both hybrid and active only buildings. A general correction factor was generated to be applied to the f-Chart method to produce more accurate and useful results for hybrid systems.

  8. Heat and Dust in Active Layers of Protostellar Disks

    Bai, Xue-Ning

    2009-01-01

    Requirements for magnetic coupling and accretion in the active layer of a protostellar disk are re-examined, and some implications for thermal emission from the layer are discussed. The ionization and electrical conductivity are calculated following the general scheme of Ilgner and Nelson but with an updated UMIST database of chemical reactions and some improvements in the grain physics, and for the minimum-mass solar nebula rather than an alpha disk. The new limits on grain abundance are slightly more severe than theirs. Even for optimally sized grains, the layer should be at least marginally optically thin to its own thermal radiation, so that narrow, highly saturated emission lines of water and other molecular species would be expected if accretion is driven by turbulence and standard rates of ionization prevail. If the grain size distribution extends broadly from well below a micron to a millimeter or more, as suggested by observations, then the layer may be so optically thin that its cooling is dominated...

  9. On the relationship between photospheric footpoint motions and coronal heating in solar active regions

    Coronal heating theories can be classified as either direct current (DC) or alternating current (AC) mechanisms, depending on whether the coronal magnetic field responds quasi-statically or dynamically to the photospheric footpoint motions. In this paper we investigate whether photospheric footpoint motions with velocities of 1-2 km s–1 can heat the corona in active regions, and whether the corona responds quasi-statically or dynamically to such motions (DC versus AC heating). We construct three-dimensional magnetohydrodynamic models for the Alfvén waves and quasi-static perturbations generated within a coronal loop. We find that in models where the effects of the lower atmosphere are neglected, the corona responds quasi-statically to the footpoint motions (DC heating), but the energy flux into the corona is too low compared to observational requirements. In more realistic models that include the lower atmosphere, the corona responds more dynamically to the footpoint motions (AC heating) and the predicted heating rates due to Alfvén wave turbulence are sufficient to explain the observed hot loops. The higher heating rates are due to the amplification of Alfvén waves in the lower atmosphere. We conclude that magnetic braiding is a highly dynamic process.

  10. Effect of heat treatment on anodic activation of aluminium by trace element indium

    Graver, Brit [Department of Materials Science and Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Helvoort, Antonius T.J. van [Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Nisancioglu, Kemal, E-mail: kemal.nisancioglu@material.ntnu.n [Department of Materials Science and Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

    2010-11-15

    Research highlights: {yields} Indium segregation activates AlIn alloy surface anodically in chloride solution. {yields} Enrichment of In on Al surface can occur thermally by heat treatment at 300 {sup o}C. {yields} Increasing temperature homogenises indium in aluminium reducing anodic activation. {yields} Indium can activate AlIn surface by segregating through dealloying of aluminium. {yields} Anodic activation is caused by AlIn amalgam formation at aluminium surface. - Abstract: The presence of trace elements in Group IIIA-VA is known to activate aluminium anodically in chloride environment. The purpose of this paper is to investigate the surface segregation of trace element In by heat treatment and resulting surface activation. Model binary AlIn alloys, containing 20 and 1000 ppm by weight of In, were characterized after heat treatment at various temperatures by use of glow discharge optical emission spectroscopy, electron microscopy and electrochemical polarization. Heat treatment for 1 h at 300 {sup o}C gave significant segregation of discrete In particles (thermal segregation), which activated the surface. Indium in solid solution with aluminium, obtained by 1 h heat treatment at 600 {sup o}C, also activated by surface segregation of In on alloy containing 1000 ppm In, resulting from the selective dissolution of the aluminium component during anodic oxidation (anodic segregation). The effect of anodic segregation was reduced by decreasing indium concentration in solid solution; it had negligible effect at the 20 ppm level. The segregated particles were thought to form a liquid phase alloy with aluminium during anodic polarization, which in turn, together with the chloride in the solution destabilized the oxide.

  11. Leishmania amazonensis: effects of heat shock on ecto-ATPase activity.

    Peres-Sampaio, Carlos Eduardo; de Almeida-Amaral, Elmo Eduardo; Giarola, Naira Ligia Lima; Meyer-Fernandes, José Roberto

    2008-05-01

    In this work we demonstrated that promastigotes of Leishmania amazonensis exhibit an Mg-dependent ecto-ATPase activity, which is stimulated by heat shock. The Mg-dependent ATPase activity of cells grown at 22 and 28 degrees C was 41.0+/-5.2 nmol Pi/h x 10(7)cells and 184.2+/-21.0 nmol Pi/h x 10(7)cells, respectively. When both promastigotes were pre-incubated at 37 degrees C for 2h, the ATPase activity of cells grown at 22 degrees C was increased to 136.4+/-10.6 nmol Pi/h x 10(7) whereas that the ATPase activity of cells grown at 28 degrees C was not modified by the heat shock (189.8+/-10.3 nmol Pi/h x 10(7)cells). It was observed that Km of the enzyme from cells grown at 22 degrees C (Km=980.2+/-88.6 microM) was the same to the enzyme from cells grown at 28 degrees C (Km=901.4+/-91.9 microM). In addition, DIDS (4,4'-diisothiocyanatostilbene 2,2'-disulfonic acid) and suramin, two inhibitors of ecto-ATPases, also inhibited similarly the ATPase activities from promastigotes grown at 22 and 28 degrees C. We also observed that cells grown at 22 degrees C exhibit the same ecto-phosphatase and ecto 3'- and 5'-nucleotidase activities than cells grown at 28 degrees C. Interestingly, cycloheximide, an inhibitor of protein synthesis, suppressed the heat-shock effect on ecto-ATPase activity of cells grown at 22 degrees C were exposed at 37 degrees C for 2h. A comparison between the stimulation of the Mg-dependent ecto-ATPase activity of virulent and avirulent promastigotes by the heat shock showed that avirulent promastigotes had a higher stimulation than virulent promastigotes after heat stress. PMID:18295760

  12. "Hot" Non-flaring Plasmas in Active Region Cores Heated by Single Nanoflares

    Barnes, Will Thomas; Cargill, Peter; Bradshaw, Stephen

    2016-05-01

    We use hydrodynamic modeling tools, including a two-fluid development of the EBTEL code, to investigate the properties expected of "hot" (i.e. between 106.7 and 107.2 K) non-flaring plasmas due to nanoflare heating in active regions. Here we focus on single nanoflares and show that while simple models predict an emission measure distribution extending well above 10 MK that is consistent with cooling by thermal conduction, many other effects are likely to limit the existence and detectability of such plasmas. These include: differential heating between electrons and ions, ionization non-equilibrium and, for short nanoflares, the time taken for the coronal density to increase. The most useful temperature range to look for this plasma, often called the "smoking gun" of nanoflare heating, lies between 1 MK and 10 MK. Signatures of the actual heating may be detectable in some instances.

  13. Active Power Flow Optimization of Industrial Power Supply with Regard to the Transmission Line Conductor Heating

    Leyzgold D.Yu.

    2015-04-01

    Full Text Available This article studies the problem of the transmission line conductor heating effect on the active power flows optimization in the local segment of industrial power supply. The purpose is to determine the optimal generation rating of the distributed power sources, in which the power flow values will correspond to the minimum active power losses in the power supply. The timeliness is the need to define the most appropriate rated power values of distributed sources which will be connected to current industrial power supply. Basing on the model of active power flow optimization, authors formulate the description of the nonlinear transportation problem considering the active power losses depending on the transmission line conductor heating. Authors proposed a new approach to the heating model parameters definition based on allowable current loads and nominal parameters of conductors as part of the optimization problem. Analysis of study results showed that, despite the relatively small active power losses reduction to the tune 0,45% due to accounting of the conductors heating effect for the present configuration of power supply, there are significant fluctuations in the required generation rating in nodes of the network to 9,32% within seasonal changes in the outer air temperature. This fact should be taken into account when selecting the optimum power of distributed generation systems, as exemplified by an arbitrary network configuration.

  14. B decays

    Stone, Sheldon

    1992-01-01

    The study of b quarks has now reached a stage where it is useful to review what has been learned so far and also to look at the implications of future studies. The most important observations thus far - measurement of the "B" lifetime, B 0 - B 0 mixing, and the observation of b? u transitions, as well as more mundane results on hadronic and semileptonic transitions - are described in detail by experimentalists who have been closely involved with the measurements. Theoretical progress in understanding b quark decays, including the mechanisms of hadronic and semileptonic decays, are described. S

  15. Optimizing VANDLE for Decay Spectroscopy

    Brewer, N. T.; Taylor, S. Z.; Grzywacz, R.; Madurga, M.; Paulauskas, S. V.; Cizewski, J. A.; Peters, W. A.; Vandle Collaboration

    2013-10-01

    Understanding the decay properties of neutron rich isotopes has well established importance to the path of the r-process and to the total decay heat for reactor physics. Specifically, the half-life, branching ratio and spectra for β-n decay is of particular interest. With that in mind, we have continued attempts to improve upon the Versatile Array of Neutron Detectors at Low Energy (VANDLE) in terms of efficiency and TOF resolution through the use of new and larger scintillators. Details of the new implementation, design and characterization of the array will be shown and compared to previous results.

  16. DIAGNOSING THE TIME DEPENDENCE OF ACTIVE REGION CORE HEATING FROM THE EMISSION MEASURE. II. NANOFLARE TRAINS

    Reep, J. W.; Bradshaw, S. J. [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States); Klimchuk, J. A., E-mail: jeffrey.reep@rice.edu, E-mail: stephen.bradshaw@rice.edu, E-mail: james.a.klimchuk@nasa.gov [NASA Goddard Space Flight Center, Solar Physics Lab., Code 671, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2013-02-20

    The time dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution coolward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of active region core emission measures. We now turn our attention to heating by a finite succession of impulsive events for which the timescale between events on a single magnetic strand is shorter than the cooling timescale. We refer to this scenario as a 'nanoflare train' and explore a parameter space of heating and coronal loop properties with a hydrodynamic model. Our conclusions are (1) nanoflare trains are consistent with 86% to 100% of observed active region cores when uncertainties in the atomic data are properly accounted for; (2) steeper slopes are found for larger values of the ratio of the train duration {Delta} {sub H} to the post-train cooling and draining timescale {Delta} {sub C}, where {Delta} {sub H} depends on the number of heating events, the event duration and the time interval between successive events ({tau} {sub C}); (3) {tau} {sub C} may be diagnosed from the width of the hot component of the emission measure provided that the temperature bins are much smaller than 0.1 dex; (4) the slope of the emission measure alone is not sufficient to provide information about any timescale associated with heating-the length and density of the heated structure must be measured for {Delta} {sub H} to be uniquely extracted from the ratio {Delta} {sub H}/{Delta} {sub C}.

  17. Development of analysis code of immersed decay heat removal system for fast reactor%快堆浸入式事故余热排出系统程序开发

    钱鸿涛; 李政昕; 胡文军; 宫宇

    2015-01-01

    To meet the need of demonstration fast reactor design,a thermal-hydraulic analysis code of immersed decay heat remov-al system was developed based on a French fast reactor system code OASIS,with the introduction of the thermal stratification and inter-wrapper flow models.An integrated model was developed for the decay heat removal system of CEFR using the code,and the performances at steady and transient station black-out were analyzed.The calculation results were validated with other codes.%针对示范快堆的设计需要,在法国快堆系统程序 OASIS 的基础上,引入热分层与盒间流模型,开发了浸入式事故余热排出系统分析程序。利用该程序对 CEFR 的非能动事故余热排出系统进行了整体建模,分析了稳态和全厂断电工况下的性能,并利用其他系统程序的结果进行了验证。结果表明:该程序能较好地反映事故余热排出系统的瞬态变化过程。

  18. Dipeptidase activity and growth of heat-treated commercial dairy starter culture.

    Garbowska, Monika; Pluta, Antoni; Berthold-Pluta, Anna

    2015-03-01

    Growing expectations of consumers of fermented dairy products urge the search for novel solutions that would improve their organoleptic properties and in the case of rennet cheeses-that would also accelerate their ripening process. The aim of this study was to determine the peptidolytic activities and growth of heat-treated commercial culture of lactic acid bacteria. The analyzed culture was characterized by a relatively high peptidolytic activity. The growth of bacterial culture subjected to heat treatment at 50-80 °C for 15 s, 10 and 3 min was delayed by a few or 10-20 h compared to the control culture. Based on the results achieved, it may be concluded that in the production of rennet cheeses, the application of additional, fermentation-impaired starter cultures (via heating for ten or so minutes) may serve to accelerate their ripening and to improve their sensory attributes. PMID:25542242

  19. Compound A, a selective glucocorticoid receptor modulator, enhances heat shock protein Hsp70 gene promoter activation.

    Ilse M Beck

    Full Text Available Compound A possesses glucocorticoid receptor (GR-dependent anti-inflammatory properties. Just like classical GR ligands, Compound A can repress NF-κB-mediated gene expression. However, the monomeric Compound A-activated GR is unable to trigger glucocorticoid response element-regulated gene expression. The heat shock response potently activates heat shock factor 1 (HSF1, upregulates Hsp70, a known GR chaperone, and also modulates various aspects of inflammation. We found that the selective GR modulator Compound A and heat shock trigger similar cellular effects in A549 lung epithelial cells. With regard to their anti-inflammatory mechanism, heat shock and Compound A are both able to reduce TNF-stimulated IκBα degradation and NF-κB p65 nuclear translocation. We established an interaction between Compound A-activated GR and Hsp70, but remarkably, although the presence of the Hsp70 chaperone as such appears pivotal for the Compound A-mediated inflammatory gene repression, subsequent novel Hsp70 protein synthesis is uncoupled from an observed CpdA-induced Hsp70 mRNA upregulation and hence obsolete in mediating CpdA's anti-inflammatory effect. The lack of a Compound A-induced increase in Hsp70 protein levels in A549 cells is not mediated by a rapid proteasomal degradation of Hsp70 or by a Compound A-induced general block on translation. Similar to heat shock, Compound A can upregulate transcription of Hsp70 genes in various cell lines and BALB/c mice. Interestingly, whereas Compound A-dependent Hsp70 promoter activation is GR-dependent but HSF1-independent, heat shock-induced Hsp70 expression alternatively occurs in a GR-independent and HSF1-dependent manner in A549 lung epithelial cells.

  20. Dehydration, Heat Stroke, or Hyponatremia? The Recognition, Treatment, and Prevention of Hyponatremia Caused by High Exercise Outdoor Activities.

    Cochran, Brent

    Hyponatremia (severe sodium depletion) has symptoms similar to heat exhaustion and heat stroke and can easily be misdiagnosed. The number of wilderness users and extreme adventure activities has increased in recent years, and more cases are being diagnosed. Given that a 1993 study found that 1 in 10 cases of heat-related illnesses were…

  1. Electric space heating scheduling for real-time explicit power control in active distribution networks

    Costanzo, Giuseppe Tommaso; Bernstein, Andrey; Chamorro, Lorenzo Reyes;

    2015-01-01

    This paper presents a systematic approach for abstracting the flexibility of a building space heating system and using it within a composable framework for real-time explicit power control of microgrids and, more in general, active distribution networks. In particular, the proposed approach is de...

  2. Buildings as solar heat stores. Heating system control and room activation; Das Gebaeude als Solarspeicher. Heizungsregelung mit Raumaktivierung

    Heckmeier, J. [Orange Energy, Schweitenkirchen (Germany); SHK-Betrieb Josef Heckmeier Haustechnik (Germany)

    2007-08-15

    When solar heating systems are used as auxiliary heating systems, there is often a gap between heat production and heat demand, especially with large collector surfaces. An intelligent control concept (innovative room bus system) is presented which narrows this gap and makes a significant contribution to energy conservation and CO2 reduction. The newly developed system also offers high comfort and user-friendliness. (orig.)

  3. Thermal activation of OSL as a geothermometer for quartz grain heating during fault movements

    Rink, W J; Rees-Jones, J; Schwarcz, H P

    1999-01-01

    In discussions of ESR dating of fault movements, there has been much debate whether zeroing of ESR signals is a mechanical shearing effect or caused by frictional heating. The OSL (optically stimulated luminescence) sensitivity of quartz is known to increase after heating. This thermal activation of dose response of the OSL in quartz should be useful as a geothermometer to test whether quartz particles in fault gouge had been heated. We tested the OSL sensitivities of quartz from fault gouge, and from a control (quartz grains from sandstone) and were able to show heat-induced enhancement of OSL sensitivity to a test dose. We observed that relative enhancement of OSL dose response (ratio of heated to unheated single aliquots) is significantly less for the finest grains (45-75 and 100-150 mu m) compared with coarser grains (150-250 mu m). These data are consistent with a model of zeroing of the quartz grains during faulting, by frictional heating localized to the grain boundaries, which would be expected to aff...

  4. Dipeptidase Activity and Growth of Heat-Treated Commercial Dairy Starter Culture

    Garbowska, Monika; Pluta, Antoni; Berthold-Pluta, Anna

    2014-01-01

    Growing expectations of consumers of fermented dairy products urge the search for novel solutions that would improve their organoleptic properties and in the case of rennet cheeses-that would also accelerate their ripening process. The aim of this study was to determine the peptidolytic activities and growth of heat-treated commercial culture of lactic acid bacteria. The analyzed culture was characterized by a relatively high peptidolytic activity. The growth of bacterial culture subjected to...

  5. Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows.

    Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

    2015-06-01

    Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (Pbiomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future. PMID:26055916

  6. PARP-1 transcriptional activity is regulated by sumoylation upon heat shock.

    Martin, Nadine; Schwamborn, Klaus; Schreiber, Valérie; Werner, Andreas; Guillier, Christelle; Zhang, Xiang-Dong; Bischof, Oliver; Seeler, Jacob-S; Dejean, Anne

    2009-11-18

    Heat shock and other environmental stresses rapidly induce transcriptional responses subject to regulation by a variety of post-translational modifications. Among these, poly(ADP-ribosyl)ation and sumoylation have received growing attention. Here we show that the SUMO E3 ligase PIASy interacts with the poly(ADP-ribose) polymerase PARP-1, and that PIASy mediates heat shock-induced poly-sumoylation of PARP-1. Furthermore, PIASy, and hence sumoylation, appears indispensable for full activation of the inducible HSP70.1 gene. Chromatin immunoprecipitation experiments show that PIASy, SUMO and the SUMO-conjugating enzyme Ubc9 are rapidly recruited to the HSP70.1 promoter upon heat shock, and that they are subsequently released with kinetics similar to PARP-1. Finally, we provide evidence that the SUMO-targeted ubiquitin ligase RNF4 mediates heat-shock-inducible ubiquitination of PARP-1, regulates the stability of PARP-1, and, like PIASy, is a positive regulator of HSP70.1 gene activity. These results, thus, point to a novel mechanism for regulating PARP-1 transcription function, and suggest crosstalk between sumoylation and RNF4-mediated ubiquitination in regulating gene expression in response to heat shock. PMID:19779455

  7. Thermal activation of OSL as a geothermometer for quartz grain heating during fault movements

    In discussions of ESR dating of fault movements, there has been much debate whether zeroing of ESR signals is a mechanical shearing effect or caused by frictional heating. The OSL (optically stimulated luminescence) sensitivity of quartz is known to increase after heating. This thermal activation of dose response of the OSL in quartz should be useful as a geothermometer to test whether quartz particles in fault gouge had been heated. We tested the OSL sensitivities of quartz from fault gouge, and from a control (quartz grains from sandstone) and were able to show heat-induced enhancement of OSL sensitivity to a test dose. We observed that relative enhancement of OSL dose response (ratio of heated to unheated single aliquots) is significantly less for the finest grains (45-75 and 100-150 μm) compared with coarser grains (150-250 μm). These data are consistent with a model of zeroing of the quartz grains during faulting, by frictional heating localized to the grain boundaries, which would be expected to affect smaller grains more than large ones. This argues against a zeroing model in which the entire fault gouge is heated by friction. Higher laboratory preheating of sandstone quartz reduces between-aliquot variability of OSL dose response in the unheated grains to nearly zero. Unheated coarsest fault gouge grains displayed virtually no among-aliquot variability, whereas fine grains showed much larger between-aliquot variability; as with the quartz sand, variability dropped to near zero after laboratory heating, suggesting that fine grains in fault gouge have experienced a wide range of natural thermal histories during faulting. This may present a problem for ESR dating of fault gouge using the plateau method

  8. Effects of heat processing on soya bean fatty acids content and the lipoxygenase activity

    Žilić Slađana M.

    2010-01-01

    Full Text Available Effects of increased temperatures on the lipoxygenase activity and changes of soya bean fatty acids were observed in the present study. The kernels of soya bean cultivars Bosa and ZPS 015 were subjected to the treatments of extrusion, autoclaving, micronisation and microwave roasting. Depending on the technological processing procedure, the kernels were exposed to temperatures ranging from 60 to 150°C for 25 to 30 seconds during extrusion and for 30 minutes during autoclaving. The temperature that developed in the course of the microwave radiation and autoclaving did not cause statistically significant differences between oil content in heat treated and fresh kernels of soya bean. However, the oil content was higher in soya bean flakes (micronized kernels and lower in grits than in fresh kernels. The heat treatments resulted in the significant decrease of the linolenic fatty acid content. Depending on the temperature and applied heat treatments, the content of linoleic and oleic fatty acid oscillated. High temperatures caused changes in unsaturated fatty acids with 18 carbon atoms resulting in relative increase of the stearic acid content. The lipoxygenase activity decreased in correlation with increased temperatures and the time of heating. The maximum drop of the activity was observed after kernel exposure to the extrusion and micronisation processes at the temperature of 100oC. However, a significant lipoxygenase activity increase was recorded in both studied cultivars after one-minute microwave heating, i.e. at the temperature about 60°C. A further temperature increase led to a gradual denaturation of the enzyme and therefore to its decreased activity.

  9. DIAGNOSING THE TIME DEPENDENCE OF ACTIVE REGION CORE HEATING FROM THE EMISSION MEASURE. II. NANOFLARE TRAINS

    The time dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution coolward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of active region core emission measures. We now turn our attention to heating by a finite succession of impulsive events for which the timescale between events on a single magnetic strand is shorter than the cooling timescale. We refer to this scenario as a 'nanoflare train' and explore a parameter space of heating and coronal loop properties with a hydrodynamic model. Our conclusions are (1) nanoflare trains are consistent with 86% to 100% of observed active region cores when uncertainties in the atomic data are properly accounted for; (2) steeper slopes are found for larger values of the ratio of the train duration Δ H to the post-train cooling and draining timescale Δ C, where Δ H depends on the number of heating events, the event duration and the time interval between successive events (τ C); (3) τ C may be diagnosed from the width of the hot component of the emission measure provided that the temperature bins are much smaller than 0.1 dex; (4) the slope of the emission measure alone is not sufficient to provide information about any timescale associated with heating—the length and density of the heated structure must be measured for Δ H to be uniquely extracted from the ratio Δ H/Δ C.

  10. Monopole heat

    Upper bounds on the flux of monopoles incident on the Earth with velocity -5 c(1016 GeV m-1) and on the flux of monopoles incident on Jupiter with velocity -3 c(1016 GeV m-1), are derived. Monopoles moving this slowly lose sufficient energy to be stopped, and then catalyse nucleon decay, releasing heat. The limits are obtained by requiring the rate of energy release from nucleon decay to be less than the measured amount of heat flowing out from the surface of the planet. (U.K.)

  11. Effect of Activation Temperature and Heating Duration on Physical Characteristics of Activated Carbon Prepared from Agriculture Waste

    Tham Yee Jun

    2010-01-01

    Full Text Available This study was conducted to determine the physical characteristics of activated carbon prepared from durian shell in varied heating durations from 10 min to 30 min and activation temperatures of 400C and 500C. Durian shells have been characterized in term of ultimate and proximate analysis, chemical composition and thermal behaviour with a view to be used as activated carbon precursor. Durian shell activated carbon was prepared by impregnating 10g of sample in 10% (v/v concentration of phosphoric acid for 24 h, followed by carbonization at 400C and 500C with different heating durations under nitrogen atmosphere. The results showed that various treatment conditions affect the percentage of yield, BET surface area, micropore volume, and average pore diameter. The highest surface area (SBET 1024 m2/g was obtained at 500C and 20 min of heating duration with 63% of yield and 0.21 cm3/g micropore volume.

  12. Active charge/passive discharge solar heating systems: Thermal analysis and performance comparisons and performance comparisons

    Swisher, J.

    1981-06-01

    This type of system combines liquid-cooled solar collector panels with a massive integral storage component that passively heats the building interior by radiation and free convection. The TRNSYS simulation program is used to evaluate system performance and to provide input for the development of a simplified analysis method. This method, which provides monthly calculations of delivered solar energy, is based on Klein's Phi-bar procedure and data from hourly TRNSYS simulations. The method can be applied to systems using a floor slab, a structural wall, or a water tank as the storage component. Important design parameters include collector area and orientation, building heat loss, collector and heat exchanger efficiencies, storage capacity, and storage to room coupling. Performance simulation results are used for comparisons with active and passive solar designs.

  13. Novel ac Heating-dc Detection Method for Active Thermoelectric Scanning Thermal Microscopy

    Miao, Tingting; Ma, Weigang; Zhang, Xing

    2015-11-01

    A novel and reliable ac heating-dc detection method is developed for active thermoelectric scanning thermal microscopy, which can map out local thermal property imaging by point-heating and point-sensing with nanoscale spatial resolution. The thermoelectric probe is electrically heated by an ac current, and the corresponding dc thermoelectric voltage is detected. Using the measured dc voltage, the temperature information can be extracted with the known Seebeck coefficient of the thermoelectric probe. The validity and accuracy of this method have been verified by a 25.4 \\upmu m thick K-type thermocouple by both experiment and numerical simulation in high vacuum and in air. The experimental results show that the proposed method is reliable and convenient to monitor the temperature of the junction.

  14. Evaluation of a large capacity heat pump concept for active cooling of hypersonic aircraft structure

    Pagel, L. L.; Herring, R. L.

    1978-01-01

    Results of engineering analyses assessing the conceptual feasibility of a large capacity heat pump for enhancing active cooling of hypersonic aircraft structure are presented. A unique heat pump arrangement which permits cooling the structure of a Mach 6 transport to aluminum temperatures without the aid of thermal shielding is described. The selected concept is compatible with the use of conventional refrigerants, with Freon R-11 selected as the preferred refrigerant. Condenser temperatures were limited to levels compatible with the use of conventional refrigerants by incorporating a unique multipass condenser design, which extracts mechanical energy from the hydrogen fuel, prior to each subsequent pass through the condenser. Results show that it is technically feasible to use a large capacity heat pump in lieu of external shielding. Additional analyses are required to optimally apply this concept.

  15. Degradation of toluene, ethylbenzene, and xylene using heat and chelated-ferrous iron activated persulfate oxidation

    Mondal, P.; Sleep, B.

    2014-12-01

    Toluene, ethylbenze, and xylene (TEX) are common contaminants in the subsurface. Activated persulfate has shown promise for degrading a wide variety of organic compounds. However, studies of persulfate application for in situ degradation of TEX and effects on the subsequent bioremediation are limited. In this work, degradation studies of TEX in aqueous media and soil are being conducted using heat activated and chelated-ferrous iron activated persulfate oxidation in batch and flow-through column experiments. In the batch experiments, sodium persulfate is being used at different concentrations to provide an initial persulfate to TEX molar ratios between 10:1 and 100:1. Sodium persulfate solutions are being activated at 20, 37, 60, and 80 oC temperatures for the heat activated oxidation. For the chelated-ferrous iron activated oxidation, ferrous iron and citric acid, both are being used at concentration of 5 mM. In the experiments with soil slurry, a soil to water ratio of 1 to 5 is being used. Flow through water saturated column experiments are being conducted with glass columns (45 cm in length and 4 cm in diameter) uniformly packed with soils, and equilibrated with water containing TEX at the target concentrations. Both the heat activation and chelated-ferrous iron activation of persulfate are being employed in the column experiments. Future experiments are planned to determine the suitability of persulfate oxidation of TEX on the subsequent biodegradation using batch microcosms containing TEX degrading microbial cultures. In these experiments, the microbial biomass will be monitored using total phospholipids, and the microbial community will be determined using quantitative real-time polymerase chain reaction (qPCR) on the extracted DNA. This study is expected to provide suitable operating conditions for in situ chemical oxidation of TEX with activated persulfate followed by bioremediation.

  16. Evaluating the accuracy of the Distributed Activation Energy Model for biomass devolatilization curves obtained at high heating rates

    Highlights: • DAEM was applied to biomass pyrolysis using a wide range of heating rates. • The validity of the method was evaluated for high heating rates. • Activation energy of low heating rates differs from that of higher rates. - Abstract: The characteristic parameters of devolatilization, the activation energy and the frequency factor, can be obtained following different experimental approaches. In the Distributed Activation Energy Model (DAEM), these parameters are derived from several TGA curves that are typically obtained for constant, low heating rate experiments. Then, the results are used to model high heating rate processes typical of industrial combustors. In this work, a wide range of heating rates were employed to obtain different TGA curves of the biomass pyrolysis, in order to analyse the validity of DAEM when extrapolating the kinetic parameters obtained for low heating rate curves used in the laboratory to higher heating rates present in industrial applications. The TGA curves of the biomass pyrolysis employed in DAEM were varied from low heating rates (around 10 K/min, values typically found in the literature on DAEM), to high heating rates (up to 200 K/min). The differences in the activation energy and the frequency factor obtained for different heating rates, were evaluated and the validity of the model was discussed. The results show differences between the activation energy and the frequency factor obtained using low and high heating rates during the TGA tests. Therefore, if an accurate approximation is required when extrapolating the data to high heating rates, the tests should be carried out at high heating rates

  17. The production of activated carbon using the equipment of thermal power plants and heating plants

    Osintsev, K. V.; Osintsev, V. V.; Dzhundubaev, A. K.; Kim, S. P.; Al'musin, G. T.; Akbaev, T. A.; Bogatkin, V. I.

    2013-08-01

    The production technology of activated carbon using the conventional equipment of the thermal power stations and boiler houses is proposed. The obtained product is directed into the systems of chemical water preparation and water drain of enterprises. The production cycle is invariable when producing the activated carbon by the proposed technology. The fuel consumption and heat losses are considerably reduced when implementing this technology compared with the known analogs of the carbon sorbent. The production efficiency increases if small dust particles are preliminary separated and coal is activated in narrow ranges of fraction sizes.

  18. Experimental investigation on the thermal performance of heat storage walls coupled with active solar systems

    Zhao, Chunyu; You, Shijun; Zhu, Chunying; Yu, Wei

    2016-02-01

    This paper presents an experimental investigation of the performance of a system combining a low-temperature water wall radiant heating system and phase change energy storage technology with an active solar system. This system uses a thermal storage wall that is designed with multilayer thermal storage plates. The heat storage material is expanded graphite that absorbs a mixture of capric acid and lauric acid. An experiment is performed to study the actual effect. The following are studied under winter conditions: (1) the temperature of the radiation wall surface, (2) the melting status of the thermal storage material in the internal plate, (3) the density of the heat flux, and (4) the temperature distribution of the indoor space. The results reveal that the room temperature is controlled between 16 and 20 °C, and the thermal storage wall meets the heating and temperature requirements. The following are also studied under summer conditions: (1) the internal relationship between the indoor temperature distribution and the heat transfer within the regenerative plates during the day and (2) the relationship between the outlet air temperature and inlet air temperature in the thermal storage wall in cooling mode at night. The results indicate that the indoor temperature is approximately 27 °C, which satisfies the summer air-conditioning requirements.

  19. Heat Shock Factor 1 Is a Substrate for p38 Mitogen-Activated Protein Kinases.

    Dayalan Naidu, Sharadha; Sutherland, Calum; Zhang, Ying; Risco, Ana; de la Vega, Laureano; Caunt, Christopher J; Hastie, C James; Lamont, Douglas J; Torrente, Laura; Chowdhry, Sudhir; Benjamin, Ivor J; Keyse, Stephen M; Cuenda, Ana; Dinkova-Kostova, Albena T

    2016-09-15

    Heat shock factor 1 (HSF1) monitors the structural integrity of the proteome. Phosphorylation at S326 is a hallmark for HSF1 activation, but the identity of the kinase(s) phosphorylating this site has remained elusive. We show here that the dietary agent phenethyl isothiocyanate (PEITC) inhibits heat shock protein 90 (Hsp90), the main negative regulator of HSF1; activates p38 mitogen-activated protein kinase (MAPK); and increases S326 phosphorylation, trimerization, and nuclear translocation of HSF1, and the transcription of a luciferase reporter, as well as the endogenous prototypic HSF1 target Hsp70. In vitro, all members of the p38 MAPK family rapidly and stoichiometrically catalyze the S326 phosphorylation. The use of stable knockdown cell lines and inhibitors indicated that among the p38 MAPKs, p38γ is the principal isoform responsible for the phosphorylation of HSF1 at S326 in cells. A protease-mass spectrometry approach confirmed S326 phosphorylation and unexpectedly revealed that p38 MAPK also catalyzes the phosphorylation of HSF1 at S303/307, previously known repressive posttranslational modifications. Thus, we have identified p38 MAPKs as highly efficient catalysts for the phosphorylation of HSF1. Furthermore, our findings suggest that the magnitude and persistence of activation of p38 MAPK are important determinants of the extent and duration of the heat shock response. PMID:27354066

  20. Heating Treated Carbon Nanotubes As Highly Active Electrocatalysts for Oxygen Reduction Reaction

    Graphical abstract: Heating treatment for multi-walled carbon nanotubes in the air introduces abundant structure defects which improve catalytic performances for oxygen reduction reaction (ORR). There is a positive correlation between the defect levels and ORR activities. The product shows better methanol tolerance and long-term durability than commercial Pt/C which makes it applicable in fuel cells. - Abstract: Carbon nanotubes (CNTs) have been widely developed for electrochemical energy conversion and storage devices for replacement of high-cost Pt-based catalysts. In this paper, a simple and convenient method is developed for improving the catalytic activity of CNTs in a controlled way. By simple heating treatment in the air, the multi-walled carbon nanotubes (MWCNTs) change with special morphologies, compositions and abundant defects (denoted as h-CNT). Those defects significantly improve the electrocatalytic performances for oxygen reduction reaction (ORR) which proceeds in a nearly four-electron pathway. The heating conditions have important effects on the structures and defect properties of h-CNTs which show a positive correlation between the defect levels and ORR performances. The small amounts of iron residues originated from nanotube growth and nitrogen doping during heating treatment also contribute to some catalytic activity. The inner walls of h-CNT remain intact during heating treatment and provide sufficient conductivity which facilitates charge transport during ORR. The h-CNT electrocatalyst shows better methanol tolerance and long-term durability than commercial Pt/C in alkaline media which makes it an alternative cathode catalyst in fuel cells

  1. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    Grosman, A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2004-07-01

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m{sup 2} of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m{sup 2} TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  2. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m2 of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m2 TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  3. The SIRT1 modulators AROS and DBC1 regulate HSF1 activity and the heat shock response.

    Rachel Raynes

    Full Text Available The heat shock response, the cellular response to protein damaging stress, is critical in maintaining proteostasis. The heat shock response is regulated by the transcription factor HSF1, which is activated upon heat shock and other stresses to induce the expression of molecular chaperones. SIRT1 has previously been shown to activate HSF1 by deacetylating it, leading to increased DNA binding ability. We have investigated how the heat shock response may be controlled by factors influencing SIRT1 activity. We found that heat shock results in an increase in the cellular NAD(+/NADH ratio and an increase in recruitment of SIRT1 to the hsp70 promoter. Furthermore, we found that the SIRT1 modulators AROS and DBC1 have an impact on hsp70 transcription, HSF1 acetylation status, and HSF1 recruitment to the hsp70 promoter. Therefore, AROS and DBC1 are now two new targets available for therapeutic regulation of the heat shock response.

  4. Heat production and quantitative oxidation of nutrients by physical activity in humans

    Thorbek, G; Chwalibog, André; Jakobsen, K;

    1994-01-01

    The effect of physical activity on heat production and oxidation of nutrients was measured by means of indirect calorimetry. The experiment included 6 male and 4 female healthy subjects who, during a 24-hour stay in the respiration chambers, performed, in the morning and afternoon, 15 min cycling...... with the total work of 6,750 kg m. Experiments were repeated twice (3- to 4-week interval) showing no differences between the gas exchange in the morning and afternoon and between first and second experiment. The gas exchange during cycling was about 4 times higher than during basal periods. The identical work...... of 66.2 kJ by cycling caused on average a heat increment of 309 kJ, yielding the mean energetic efficiency for the performed work of 0.22. The activity caused an increment of 11.5 g oxidized carbohydrate and 2.6 g oxidized fat....

  5. Anti-cancer activities of pH- or heat-modified pectin

    Leclere, Lionel; Van Cutsem, Pierre; Michiels, Carine

    2013-01-01

    Despite enormous efforts that have been made in the search for novel drugs and treatments, cancer continues to be a major public health problem. Moreover, the emergence of resistance to cancer chemotherapy often prevents complete remission. Researchers have thus turned to natural products mainly from plant origin to circumvent resistance. Pectin and pH- or heat-modified pectin have demonstrated chemopreventive and antitumoral activities against some aggressive and recurrent cancers. The focus...

  6. Heat-Activated Effect of Exchange Coupling Between Two Ferromagnets Separated by an Amorphous Semiconducting Barrier

    肖明文; 李正中; 许望

    2002-01-01

    We try to extend our previous zero-temperature tunnelling theory for the exchange coupling between two ferromagnets separated by an amorphous semiconducting barrier to the case of finite temperature. The result exhibits that the tunnelling electrons can absorb or emit phonons when they tunnel through the amorphous barrier at finite temperatures so that the interlayer exchange coupling is heat activated. This agrees with the experiments.

  7. Hybrid ground-source heat pump system with active air source regeneration

    Highlights: • A hybrid ground source heat pump system with two separate borefields is modelled. • The maximum underground storage temperature depends on the size of the drycooler. • Drycooler selection curves are given as function of underground storage temperature. • The size of the cold storage is reduced with 47% in the cost optimal configuration. • The cooling seasonal performance factor decreases with reduced storage capacity. - Abstract: Ground-source heat pump systems (GSHP) offer great advantages over traditional heating and cooling installations. However, their applications are limited due to the high initial costs of borehole drilling. One way to avoid these costs is by reducing the size of the borefield, e.g. by combining the system with other renewable energy sources or by using active regeneration to increase the system efficiency. In this paper a hybrid ground-source heat pump system (HGSHP) is analyzed. The borefield is split into a warm part and a cold part, which allows for seasonal thermal-energy storage. Additionally, supplementary drycoolers capture heat during summer and cold during winter. The relationship between the underground storage size and temperature and the drycooler capacity is described, using an office building in Flanders (Belgium) as reference case. Results show that with a HGSHP system a significant borefield size reduction can be achieved without compromising system performance; i.e. for the reference case a reduction of 47% was achieved in the cost-optimal configuration. It is also shown that the cooling seasonal performance factor decreases significantly with underground storage capacity. In addition, the HGSHP can be used to maintain or restore thermal balance in the geothermal source when heating and cooling loads do not match

  8. Heat stress and antioxidant enzyme activity in bubaline (Bubalus bubalis) oocytes during in vitro maturation

    Waiz, Syma Ashraf; Raies-ul-Haq, Mohammad; Dhanda, Suman; Kumar, Anil; Goud, T. Sridhar; Chauhan, M. S.; Upadhyay, R. C.

    2016-01-01

    In vitro environments like heat stress usually increase the production of reactive oxygen species in bubaline oocytes which have been implicated as one of the major causes for reduced developmental competence. Oocytes during meiotic maturation are sensitive to oxidative stress, and heat stress accelerates cellular metabolism, resulting in the higher production of free radicals. Therefore, the aim of present work was to assess the impact of heat stress during meiotic maturation on bubaline cumulus-oocyte complexes (COC), denuded oocytes (DO), and cumulus cell mass in terms of their oxidative status. Accordingly, for control group, COC were matured at 38.5 °C for complete 24 h of meiotic maturation and heat stress of 40.5 and 41.5 °C was applied to COC during the first 12 h of maturation and then moved to 38.5 °C for rest of the 12 h. In another group, COC after maturation were denuded from the surrounding cumulus cells by manual pipetting. Results indicated that the production of reactive oxygen species (ROS), lipid peroxides, and nitric oxide (NO) was significantly (P < 0.05) higher in the oocytes subjected to heat stress (40.5 and 41.5 °C) during meiotic maturation compared to the oocytes matured under standard in vitro culture conditions (38.5 °C). Also, the antioxidant enzymatic activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were significantly (P < 0.05) increased in all the treatment groups compared to the control group. Therefore, the present study clearly establishes that heat stress ensues oxidative stress in bubaline oocytes which triggers the induction of antioxidant enzymatic defense system for scavenging the ROS.

  9. Thermoregulation and heat exchange in a nonuniform thermal environment during simulated extended EVA. Extravehicular activities

    Koscheyev, V. S.; Leon, G. R.; Hubel, A.; Nelson, E. D.; Tranchida, D.

    2000-01-01

    BACKGROUND: Nonuniform heating and cooling of the body, a possibility during extended duration extravehicular activities (EVA), was studied by means of a specially designed water circulating garment that independently heated or cooled the right and left sides of the body. The purpose was to assess whether there was a generalized reaction on the finger in extreme contradictory temperatures on the body surface, as a potential heat status controller. METHOD: Eight subjects, six men and two women, were studied while wearing a sagittally divided experimental garment with hands exposed in the following conditions: Stage 1 baseline--total body garment inlet water temperature at 33 degrees C; Stage 2--left side inlet water temperature heated to 45 degrees C; right side cooled to 8 degrees C; Stage 3--left side inlet water temperature cooled to 8 degrees C, right side heated to 45 degrees C. RESULTS: Temperatures on each side of the body surface as well as ear canal temperature (Tec) showed statistically significant Stage x Side interactions, demonstrating responsiveness to the thermal manipulations. Right and left finger temperatures (Tfing) were not significantly different across stages; their dynamic across time was similar. Rectal temperature (Tre) was not reactive to prevailing cold on the body surface, and therefore not informative. Subjective perception of heat and cold on the left and right sides of the body was consistent with actual temperature manipulations. CONCLUSIONS: Tec and Tre estimates of internal temperature do not provide accurate data for evaluating overall thermal status in nonuniform thermal conditions on the body surface. The use of Tfing has significant potential in providing more accurate information on thermal status and as a feedback method for more precise thermal regulation of the astronaut within the EVA space suit.

  10. Development of JENDL Decay and Fission Yield Data Libraries

    Katakura, J.

    2014-04-01

    Decay and fission yield data of fission products have been developed for decay heat calculations to constitute one of the special purpose files of JENDL (Japanese Nuclear Data Library). The decay data in the previous JENDL decay data file have been updated based on the data extracted from ENSDF (Evaluated Nuclear Structure Data File) and those by Total Absorption Gamma-ray Spectroscopy (TAGS) measurements reported recently. Fission yield data have also been updated in order to maintain consistency between the decay and yield data files. Decay heat calculations were performed using the updated decay and yield data, and the results were compared with measured decay heat data to demonstrate their applicability. The uncertainties of the calculated results were obtained by sensitivity analyses. The resulting JENDL calculations and their uncertainty were compared with those from the ENDF and JEFF evaluated files.

  11. Zero-valent iron enhanced methanogenic activity in anaerobic digestion of waste activated sludge after heat and alkali pretreatment.

    Zhang, Yaobin; Feng, Yinghong; Quan, Xie

    2015-04-01

    Heat or alkali pretreatment is the effective method to improve hydrolysis of waste sludge and then enhance anaerobic sludge digestion. However the pretreatment may inactivate the methanogens in the sludge. In the present work, zero-valent iron (ZVI) was used to enhance the methanogenic activity in anaerobic sludge digester under two methanogens-suppressing conditions, i.e. heat-pretreatment and alkali condition respectively. With the addition of ZVI, the lag time of methane production was shortened, and the methane yield increased by 91.5% compared to the control group. The consumption of VFA was accelerated by ZVI, especially for acetate, indicating that the acetoclastic methanogenesis was enhanced. In the alkali-condition experiment, the hydrogen produced decreased from 27.6 to 18.8 mL when increasing the ZVI dosage from 0 to 10 g/L. Correspondingly, the methane yield increased from 1.9 to 32.2 mL, which meant that the H2-utilizing methanogenes was enriched. These results suggested that the addition of ZVI into anaerobic digestion of sludge after pretreated by the heat or alkali process could efficiently recover the methanogenic activity and increase the methane production and sludge reduction. PMID:25681947

  12. JENDL FP decay data file 2000

    A decay data file of fission product (FP) nuclides has been developed for the use in nuclear technology field as one of special purpose files of JENDL (Japanese Evaluated Nuclear Data Library) in the format of ENDF/B and it is called JENDL FP Decay Data File 2000. The file includes the decay data for 1229 fission product nuclides: 142 stable and 1087 unstable nuclides. The data included for a nuclide are decay modes, their Q values and branching ratios, average decay energy values of beta-rays, gamma-rays and alpha-particles and their spectral data. The primary source of the decay data is ENSDF (Evaluated Nuclear Structure Data File), which is the internationally recognized data file of nuclear structure properties. The data in ENSDF, however, cover only measured ones. The data of the short-lived nuclides needed for the application fields such as decay heat prediction are often incomplete or not measured because of their short half-lives. For such nuclides a theoretical model calculation is applied to derive the needed data such as average decay energies and spectral data. The data in JENDL FP Decay Data File 2000 have been tested by summation calculation comparing its results with measured data of decay heat values and aggregate fission product spectra of various fissioning nuclei. The comparison showed good agreement between the calculated results and the measured values. (author)

  13. Methods for determining enzymatic activity comprising heating and agitation of closed volumes

    Thompson, David Neil; Henriksen, Emily DeCrescenzo; Reed, David William; Jensen, Jill Renee

    2016-03-15

    Methods for determining thermophilic enzymatic activity include heating a substrate solution in a plurality of closed volumes to a predetermined reaction temperature. Without opening the closed volumes, at least one enzyme is added, substantially simultaneously, to the closed volumes. At the predetermined reaction temperature, the closed volumes are agitated and then the activity of the at least one enzyme is determined. The methods are conducive for characterizing enzymes of high-temperature reactions, with insoluble substrates, with substrates and enzymes that do not readily intermix, and with low volumes of substrate and enzyme. Systems for characterizing the enzymes are also disclosed.

  14. Effects of Heat Shock on Photosynthetic Properties, Antioxidant Enzyme Activity, and Downy Mildew of Cucumber (Cucumis sativus L.)

    Hao, Ting; Jin, Haijun; Zhang, Hongmei; He, Lizhong; Zhou, Qiang; Huang, Danfeng; Hui, Dafeng; Yu, Jizhu

    2016-01-01

    Heat shock is considered an abiotic stress for plant growth, but the effects of heat shock on physiological responses of cucumber plant leaves with and without downy mildew disease are still not clear. In this study, cucumber seedlings were exposed to heat shock in greenhouses, and the responses of photosynthetic properties, carbohydrate metabolism, antioxidant enzyme activity, osmolytes, and disease severity index of leaves with or without the downy mildew disease were measured. Results showed that heat shock significantly decreased the net photosynthetic rate, actual photochemical efficiency, photochemical quenching coefficient, and starch content. Heat shock caused an increase in the stomatal conductance, transpiration rate, antioxidant enzyme activities, total soluble sugar content, sucrose content, soluble protein content and proline content for both healthy leaves and downy mildew infected leaves. These results demonstrate that heat shock activated the transpiration pathway to protect the photosystem from damage due to excess energy in cucumber leaves. Potential resistance mechanisms of plants exposed to heat stress may involve higher osmotic regulation capacity related to an increase of total accumulations of soluble sugar, proline and soluble protein, as well as higher antioxidant enzymes activity in stressed leaves. Heat shock reduced downy mildew disease severity index by more than 50%, and clearly alleviated downy mildew development in the greenhouses. These findings indicate that cucumber may have a complex physiological change to resist short-term heat shock, and suppress the development of the downy mildew disease. PMID:27065102

  15. Effects of Heat Shock on Photosynthetic Properties, Antioxidant Enzyme Activity, and Downy Mildew of Cucumber (Cucumis sativus L..

    Xiaotao Ding

    Full Text Available Heat shock is considered an abiotic stress for plant growth, but the effects of heat shock on physiological responses of cucumber plant leaves with and without downy mildew disease are still not clear. In this study, cucumber seedlings were exposed to heat shock in greenhouses, and the responses of photosynthetic properties, carbohydrate metabolism, antioxidant enzyme activity, osmolytes, and disease severity index of leaves with or without the downy mildew disease were measured. Results showed that heat shock significantly decreased the net photosynthetic rate, actual photochemical efficiency, photochemical quenching coefficient, and starch content. Heat shock caused an increase in the stomatal conductance, transpiration rate, antioxidant enzyme activities, total soluble sugar content, sucrose content, soluble protein content and proline content for both healthy leaves and downy mildew infected leaves. These results demonstrate that heat shock activated the transpiration pathway to protect the photosystem from damage due to excess energy in cucumber leaves. Potential resistance mechanisms of plants exposed to heat stress may involve higher osmotic regulation capacity related to an increase of total accumulations of soluble sugar, proline and soluble protein, as well as higher antioxidant enzymes activity in stressed leaves. Heat shock reduced downy mildew disease severity index by more than 50%, and clearly alleviated downy mildew development in the greenhouses. These findings indicate that cucumber may have a complex physiological change to resist short-term heat shock, and suppress the development of the downy mildew disease.

  16. Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor

    Xingtuan Yang

    2014-01-01

    Full Text Available After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was carried out based on a one-dimensional mathematical model for steam generator and steam pipe of start-up loop to achieve safety and reliability. The results show that steam generator should be discharged and precooled; otherwise, boiling will arise and introduce a cold shock to the boiling tubes and tube sheet when coolant began to circulate prior to the helium. Additionally, in avoiding heat shock caused by the sudden load of helium, the helium circulation should be restricted to start with an extreme low flow rate; meanwhile, the coolant of steam generator (water should have flow rate as large as possible. Finally, a four-step procedure with precooling process of steam generator was recommended; sensitive study for the main parameters was conducted.

  17. Enhanced detection of hydraulically active fractures by temperature profiling in lined heated bedrock boreholes

    Pehme, P. E.; Parker, B. L.; Cherry, J. A.; Molson, J. W.; Greenhouse, J. P.

    2013-03-01

    SummaryThe effectiveness of borehole profiling using a temperature probe for identifying hydraulically active fractures in rock has improved due to the combination of two advances: improved temperature sensors, with resolution on the order of 0.001 °C, and temperature profiling within water inflated flexible impermeable liners used to temporarily seal boreholes from hydraulic cross-connection. The open-hole cross-connection effects dissipate after inflation, so that both the groundwater flow regime and the temperature distribution return to the ambient (background) condition. This paper introduces a third advancement: the use of an electrical heating cable that quickly increases the temperature of the entire static water column within the lined hole and thus places the entire borehole and its immediate vicinity into thermal disequilibrium with the broader rock mass. After heating for 4-6 h, profiling is conducted several times over a 24 h period as the temperature returns to background conditions. This procedure, referred to as the Active Line Source (ALS) method, offers two key improvements over prior methods. First, there is no depth limit for detection of fractures with flow. Second, both identification and qualitative comparison of evidence for ambient groundwater flow in fractures is improved throughout the entire test interval. The benefits of the ALS method are demonstrated by comparing results from two boreholes tested to depths of 90 and 120 m in a dolostone aquifer used for municipal water supply and in which most groundwater flow occurs in fractures. Temperature logging in the lined holes shows many fractures in the heterothermic zone both with and without heating, but only the ALS method shows many hydraulically active fractures in the deeper homothermic portion of the hole. The identification of discrete groundwater flow at many depths is supported by additional evidence concerning fracture occurrence, including continuous core visual inspection

  18. Pulsed nanosecond discharge in air at high specific deposited energy: fast gas heating and active particle production

    Popov, N. A.

    2016-08-01

    The results of a numerical study on kinetic processes initiated by a pulsed nanosecond discharge in air at high specific deposited energy, when the dissociation degree of oxygen molecules is high, are presented. The calculations of the temporal dynamics of the electron concentration, density of atomic oxygen, vibrational distribution function of nitrogen molecules, and gas temperature agree with the experimental data. It is shown that quenching of electronically excited states of nitrogen N2(B3Πg), N2(С3Πu), N2(a‧1 Σ \\text{u}- ) by oxygen molecules leads to the dissociation of O2. This conclusion is based on the comparison of calculated dynamics of atomic oxygen in air, excited by a pulsed nanosecond discharge, with experimental data. In air plasma at a high dissociation degree of oxygen molecules ([O]/[O2]  >  10%), relaxation of the electronic energy of atoms and molecules in reactions with O atoms becomes extremely important. Active production of NO molecules and fast gas heating in the discharge plasma due to the quenching of electronically excited N2(B3Πg, C3Πu, a‧1 Σ \\text{u}- ) molecules by oxygen atoms is notable. Owing to the high O atom density, electrons are effectively detached from negative ions in the discharge afterglow. As a result, the decay of plasma in the afterglow is determined by electron–ion recombination, and the electron density remains relatively high between the pulses. An increase in the vibrational temperature of nitrogen molecules at the periphery of the plasma channel at time delay t  =  1–30 μs after the discharge is obtained. This is due to intense gas heating and, as a result, gas-dynamic expansion of a hot gas channel. Vibrationally excited N2(v) molecules produced near the discharge axis move from the axial region to the periphery. Consequently, at the periphery the vibrational temperature of nitrogen molecules is increased.

  19. Radioactive decay properties of Bruce 'A' CANDUTM UO2 fuel and fuel recycle waste

    This report is a compilation of the radioactive decay properties of irradiated CANDU fuel of the type used at the Bruce Nuclear Power Generating Station. The report is similar to AECL-4436/1 and AECL-4436/2, which describe the decay properties of Pickering fuel. Using revised reference input data, the computer codes LATREP and CANIGEN II were employed to calculate the mass, activity and decay heat of the component isotopes in irradiated Bruce fuel. The decay properties of the fuel are tabulated for burnup levels of 550, 685, 865 and 1045 GJ/kg U (150, 190, 240 and 290 MWh/kg U). The decay properties for the waste that would be produced from recycling the fuel in a Purex-type process are tabulated for a burnup of 685 GJ/kg U. The total alpha, beta and gamma activity, the gamma spectra and neutron emissions of the used fuel and recycle waste are also presented. The report also presents a comparison of the CANIGEN II generated data with other codes such as ISOGEN, ORIGEN, FISSPROD-2 and earlier CANIGEN data. A detailed analysis of the differences between codes is presented along with a comparison of the ability of the codes to correctly predicts measured decay heats, radiation fields and actinide concentrations. This report is intended to provide a reference source to assist both research programs and safety assessment studies within the Canadian Nuclear Waste Management Program

  20. Heat conduction through geological mattresses from cells storing mean activity and long life nuclear wastes

    Document available in extended abstract form only. ANDRA ordered in 2008 a campaign of numerical simulations to assess the efficiency of the ventilation system designed for cells storing mean activity and long life nuclear wastes. Numerical models were performed by ACRIIN as research engineering office. The main objectives were to assess the risks of atmospheric explosions due to high rate of hydrogen and to determine the efficiency of the system to evacuate released heat from storage packages. Further calculations have been carried out to evaluate temperature gradients in the surrounding geological medium. Three-dimensional numerical models of a reference cell were built to simulate the air flow injected at the cell entrance and retrieved and the other extremity. The reference case is based on a cell full of storage packages, with rows and columns of packages methodically ordered. Analytic and numerical calculations have been performed introducing progressively each complex physical phenomenon in order to dissociate origins of transport of released mass or heat. Three kinds of flows have been physically distinguished: 1) Ventilation in a cell with storage package that are thermally inert, i.e. no heat release, but with hydrogen release. 2) Flow in a cell with storage packages that emit heat and warm the injected air, supposing that no heat were lost towards the surrounding concrete walls of the cell. 3) Air Flow warmed by the storage packages with heat losses towards concrete walls and geological medium. Simulations with absence of thermal effects allowed the knowledge of main topics of the ventilation air flows that may be synthesized as follows: - Flows infiltrate clearances between piles and rows of storage packages. Such apertures are a few centimetres wide. The flow is disorganised between the first rows, with distribution in both transversal and longitudinal directions. After a few tens of rows, the flow reaches its hydraulic equilibrium, with a nearly pure

  1. THE WAY OF GENERATION THE HIGH-GRADE HEAT ENERGY DURING +- AND –– DECAY IN THE CHAIN NOT-RAMIFIED NUCLEAR TRANSFORMATIONS

    Лавренченко, Г. К.; Семенишин, Н. Н.; Волков, В. Е.; Куриннов, Г. В.

    2015-01-01

    The present ways of reception the high-grade heat energy (HGHE) with temperatures higher 2500 K have a number of defects, the main of which — low efficiency. In the generator realizing an offered new way of manufacture HGHE as a working body is used superheated water vapor. On the initial stage in process of plasma-formation in a flow of water vapor are appears the oxygen’s ions, hydroxyls, free electrons and what most important — protons. Protons are separate the from this flow during its pa...

  2. High heat flux actively cooled plasma facing components development, realisation and first results in Tore Supra

    The development, design, manufacture and testing of actively cooled high heat flux (HHF) plasma facing components (PFCs) has been an essential part of the Tore Supra programme towards long powerful tokamak operation. The Tore Supra PFC programme has culminated in the installation and operation of a toroidal pump limiter, since 2002, which already allowed to reach new world records in steady state operation (1 GJ injected in a 6 min discharge). The HHF PFCs development and manufacturing was achieved through a long lead development and industrialisation programme (about 10 years) marked out with a number of challenges. The major technical topics cope with bonding technology analysis involving an adequate material selection and procurement, repair processes development and implementation, development of destructive and non-destructive testing methods, and more generally industrialisation assessment. All these lessons are relevant to the ITER divertor PFCs manufacturing, although the technical solution adopted for Tore Supra (flat tiles concept) is different from the one proposed for the ITER divertor (monoblock concept). The routine operation of the actively cooled toroidal pumped limiter (TPL), capable to sustain up to 10 MW m-2 of nominal convected heat flux, is described. Up to now, the limiter fulfills its objectives in terms of heat exhaust. However, the thermographic monitoring exhibits unexpected behavior of the surface temperature. Particle exhaust control displays a complex pattern, due to the high fraction of the injected deuterium, which remains in the wall. The first experimental results with a full actively cooled wall gives access to ITER relevant information on wall conditioning, hydrogen plasma density and vacuum vessel inventory control, carbon erosion and redeposition and capability of in situ monitoring in a completely actively cooled environment

  3. Observations of HF backscatter decay rates from HAARP generated FAI

    Bristow, William; Hysell, David

    2016-07-01

    Suitable experiments at the High-frequency Active Auroral Research Program (HAARP) facilities in Gakona, Alaska, create a region of ionospheric Field-Aligned Irregularities (FAI) that produces strong radar backscatter observed by the SuperDARN radar on Kodiak Island, Alaska. Creation of FAI in HF ionospheric modification experiments has been studied by a number of authors who have developed a rich theoretical background. The decay of the irregularities, however, has not been so widely studied yet it has the potential for providing estimates of the parameters of natural irregularity diffusion, which are difficult measure by other means. Hysell, et al. [1996] demonstrated using the decay of radar scatter above the Sura heating facility to estimate irregularity diffusion. A large database of radar backscatter from HAARP generated FAI has been collected over the years. Experiments often cycled the heater power on and off in a way that allowed estimates of the FAI decay rate. The database has been examined to extract decay time estimates and diffusion rates over a range of ionospheric conditions. This presentation will summarize the database and the estimated diffusion rates, and will discuss the potential for targeted experiments for aeronomy measurements. Hysell, D. L., M. C. Kelley, Y. M. Yampolski, V. S. Beley, A. V. Koloskov, P. V. Ponomarenko, and O. F. Tyrnov, HF radar observations of decaying artificial field aligned irregularities, J. Geophys. Res. , 101, 26,981, 1996.

  4. 主动蓄放热-热泵联合加温系统在日光温室的应用%Application of heating system with active heat storage-release and heat pump in solar greenhouse

    孙维拓; 杨其长; 方慧; 张义; 管道平; 卢威

    2013-01-01

    The Chinese solar greenhouse has a unique greenhouse structure that regards solar energy as the main energy source, and has characteristics such as high efficiency, energy saving, and low cost. During a cold winter night, air temperature inside a solar greenhouse is low for crop growth, which would affect crop yield and quality, due to the heat-transfer characteristics and heat capacity limit of the north wall. In recent years, in trying to promote the heat storage capacity of the solar greenhouse, the thought of active heat storage-release came forward. Solar energy is a kind of clean renewable energy, but has intermittent and unstable performance when used for greenhouse heating. Meanwhile, the heat collecting efficiency of the solar thermal collector decreases with an increase in operating temperature. Thus, an active heat storage-release system (AHSRS) is difficult to use to ensure an appropriate temperature for a solar greenhouse in a frigid region or when it encounters weather conditions with weak solar radiation. As an efficient means of raising low-grade energy, the heat pump has been more and more applied to greenhouse heating which can reduce the operating temperature of the AHSRS when used in combination. In order to promote heating performance and stability of the AHSRS and improve air temperature inside a solar greenhouse at night, based on the concept of active heat storage-release, an active heat storage-release associated with heat pump heating system (AHSRHPS) applicable to solar greenhouse heating was designed in the present study. During the day, the solar energy reaching the north wall surface was absorbed by the circulating water and stored in reservoirs when the AHSRS was running. Running the heat pump unit was intended to promote low-grade heat energy and reduce the circulating water temperature which contributes to increasing the heat collecting efficiency of the AHSRS and maximum water temperature of the reservoir. When air temperature

  5. Neutral-Line Magnetic Shear and Enhanced Coronal Heating in Solar Active Regions

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Gary, G. A.; Shimizu, T.

    1997-01-01

    By examining the magnetic structure at sites in the bright coronal interiors of active regions that are not flaring but exhibit persistent strong coronal heating, we establish some new characteristics of the magnetic origins of this heating. We have examined the magnetic structure of these sites in five active regions, each of which was well observed by both the Yohkoh SXT and the Marshall Space Flight Center Vector Magnetograph and showed strong shear in its magnetic field along part of at least one neutral line (polarity inversion). Thus, we can assess whether this form of nonpotential field structure in active regions is a characteristic of the enhanced coronal heating and vice versa. From 27 orbits' worth of Yohkoh SXT images of the five active regions, we have obtained a sample of 94 persistently bright coronal features (bright in all images from a given orbit), 40 long (greater than or approximately equals 20,000 km) neutral-line segments having strong magnetic shear throughout (shear angle greater than 45 deg), and 39 long neutral-line segments having weak magnetic shear throughout (shear angle less than 45 deg). From this sample, we find that: (1) all of our persistently bright coronal features are rooted in magnetic fields that are stronger than 150 G; (2) nearly all (95%) of these enhanced coronal features are rooted near neutral lines (closer than 10,000 km); (3) a great majority (80%) of the bright features are rooted near strong-shear portions of neutral lines; (4) a great majority (85%) of long strong-shear segments of neutral lines have persistently bright coronal features rooted near them; (5) a large minority (40%) of long weak-shear segments of neutral lines have persistently bright coronal features rooted near them; and (6) the brightness of a persistently bright Coronal feature often changes greatly over a few hours. From these results, we conclude that most persistent enhanced heating of coronal loops in active regions: (1) requires the

  6. The decay of 120Ba

    120Ba was produced by bombarding a 2 mg/cm2 thick 106Cd target with a 68 MeV 16O beam and fluorated in a helium-jet ion source. The decay of on-line mass separated activity 120Ba has been studied by γ-X, γ-γ and γ-β coincidence measurements. Its half-life was measured to be 24 ± 2s. The total decay energy was extracted to be QEG 5.0 ± 0.3 MeV. A simple decay scheme has been proposed

  7. Comparison of swimming pools alternative passive and active heating systems based on renewable energy sources in Southern Europe

    This article examines different passive and active heating systems for swimming pools. The passive systems introduced in this article are: * The swimming pools' enclosure. * The placement of floating insulating covers on the pools' surfaces whenever they are not used. The examined active systems in this article are: * A biomass heater. * A biomass heater and solar collectors combi-system. * Vertical geothermal heat exchangers (GHE) co-operating with geothermal heat pumps (GHP). The methodology employed for the introduced systems' evaluation is the arithmetic computational simulation of the swimming pools' annual heating, using annual time series of averaged hourly values for the available solar radiation and the calculated pools' thermal power demand (heating loads). The dimensioning of the active systems aims at the maximisation of the heating production from R.E.S. (renewable energy sources). and the optimisation of the corresponding investments' economic indexes. The examined systems are evaluated technically and economically versus fundamental criteria. It is proved that significant reduction of the heating loads is achieved with the introduced passive systems. The reduced swimming pools' heating loads can be successfully covered by the proposed R.E.S. active systems. The fossil fuels consumption is eliminated. The corresponding investments' payback periods can be lower than 5 years. - Highlights: • The passive solar systems reduce the swimming pools heating loads more than 90%. • The examined active heating system exhibit payback periods lower than 3.5 years. • The energy saving is maximised with a biomass heater – solar collectors system. • Single biomass heaters exhibits the shortest payback period. • GHE–GHP can be used in cases of low solar radiation and lack of biomass fuels

  8. Dual-reporter in vivo imaging of transient and inducible heat-shock promoter activation.

    Fortin, Pierre-Yves; Genevois, Coralie; Chapolard, Mathilde; Santalucía, Tomàs; Planas, Anna M; Couillaud, Franck

    2014-02-01

    Gene promoter activity can be studied in vivo by molecular imaging methods using reporter gene technology. Transcription of the reporter and the reported genes occurs simultaneously. However, imaging depends on reporter protein translation, stability, and cellular fate that may differ among the various proteins. A double transgenic mouse strain expressing the firefly luciferase (lucF) and fluorescent mPlum protein under the transcriptional control of the thermo-inducible heat-shock protein (Hspa1b) promoter was generated allowing to follow up the reporter proteins by different and complementary in vivo imaging technologies. These mice were used for in vivo imaging by bioluminescence and epi fluorescence reflectance imaging (BLI & FRI) and as a source of embryonic fibroblast (MEF) for in vitro approaches. LucF, mPlum and endogenous Hsp70 mRNAs were transcribed simultaneously. The increase in mRNA was transient, peaking at 3 h and then returning to the basal level about 6 h after the thermal stimulations. The bioluminescent signal was transient and initiated with a 3 h delay versus mRNA expression. The onset of mPlum fluorescence was more delayed, increasing slowly up to 30 h after heat-shock and remaining for several days. This mouse allows for both bioluminescence imaging (BLI) and fluorescence reflectance imaging (FRI) of Hsp70 promoter activation showing an early and transient lucF activity and a retrospective and persistent mPlum fluorescence. This transgenic mouse will allow following the transient local induction of Hsp-70 promoter beyond its induction time-frame and relate into subsequent dynamic biological effects of the heat-shock response. PMID:24575340

  9. Parametric Study to Characterize Low Activity Waste Tank Heat Removal Alternatives for Phase 1 Specification Development

    Alternative for removing heat from Phase 1, low-activity waste feed double-shell tanks using the ventilation systems have been analyzed for Phase 1 waste feed delivery. The analysis was a parametric study using a model that predicted the waste temperatures for a range of primary and annulus ventilation system flow rates. The analysis was performed to determine the ventilation flow required to prevent the waste temperature from exceeding the Limiting Conditions for Operation limits during normal operation and the Safety Limits during off-normal events

  10. Transcriptional activation by heat and cold of a thiol protease gene in tomato. [Lycopersicon esculentum

    Schaffer, M.A.; Fischer, R.L. (Univ. of California, Berkeley (USA))

    1990-08-01

    We previously determined that low temperature induces the accumulation in tomato (Lycopersicon esculentum) fruit of a cloned mRNA, designated C14, encoding a polypeptide related to thiol proteases. We now demonstrate that C14 mRNA accumulation is a response common to both high (40{degree}C) and low (4{degree}C) temperature stresses. Exposure of tomato fruit to 40{degree}C results in the accumulation of C14 mRNA, by 8 hours. This response is more rapid than that to 4{degree}C, but slower than the induction of many heat shock messages by 40{degree}C, and therefore unique. We have also studied the mechanism by which heat and cold exposure activate C14 gene expression. Both high and low temperature regulate protease gene expression through transcriptional induction of a single C14 gene. A hypothesis for the function of C14 thiol protease gene expression in response to heat and cold is discussed.

  11. Adsorption of SO2 onto oxidized and heat-treated activated carbon fibers (ACFS)

    Daley, M.A.; Mangun, C.L.; DeBarr, J.A.; Riha, S.; Lizzio, A.A.; Donnals, G.L.; Economy, J.

    1997-01-01

    A series of activated carbon fibers (ACFs) and heat-treated oxidized ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore surface chemistry and pore volume for the adsorption of SO2 and its catalytic conversion to H2SO4. For untreated ACFs, the initial rate of SO2 adsorption from flue gas was shown to be inversely related to pore size. At longer times, the amount of SO2 adsorbed from flue gas was dependent on both the pore size and pore volume. Oxidation of the ACFs, using an aqueous oxidant, decreased their adsorption capacity for SO2 from flue gas due to a decrease in pore volume and repulsion of the SO2 from acidic surface groups. If these samples were heat-treated to desorb the oxygen containing function groups, the amount of SO2 adsorption increased. This increase in adsorption capacity was directly correlated to the amount of CO2 evolved during heat-treatment of the oxidized ACFs. The amount of SO2 adsorbed for these samples was related to the pore size, pore surface chemistry and pore volume. This analysis is explained in more detail in this paper. ?? 1997 Elsevier Science Ltd. All rights reserved.

  12. Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity

    Fernandes, E.K.K.; Keyser, C.A.; Chong, J.P.; Rangel, D.E.N.; Miller, M.P.; Roberts, D.W.

    2010-01-01

    Aims: The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties. Methods and Results: Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5??8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 ?? 0??2??C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae (Ma-an) and Metarhizium from the flavoviride complex (Mf) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum (Ma-ac) isolates demonstrated high heat tolerance (c. 70-100% RG). Conidial suspensions also were plated on PDAY and incubated at 5??C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG). Conclusions: Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties. Significance and Impact of the Study: Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes. ?? 2009 The Society for Applied Microbiology.

  13. The effects of excessive heat on heat-activated membrane currents in cultured dorsal root ganglia neurons from neonatal rat

    Lyfenko, Alla; Vlachová, Viktorie; Vyklický st., Ladislav; Dittert, Ivan; Kress, M.; Reeh, P. W.

    2002-01-01

    Roč. 95, č. 3 (2002), s. 207-214. ISSN 0304-3959 R&D Projects: GA ČR GA305/00/1639; GA MŠk LN00B122 Institutional research plan: CEZ:AV0Z5011922 Keywords : nociception * noxious heat * capsacin Subject RIV: ED - Physiology Impact factor: 4.829, year: 2002

  14. Semileptonic Decays

    Luth, Vera G.; /SLAC

    2012-10-02

    The following is an overview of the measurements of the CKM matrix elements |V{sub cb}| and |V{sub ub}| that are based on detailed studies of semileptonic B decays by the BABAR and Belle Collaborations and major advances in QCD calculations. In addition, a new and improved measurement of the ratios R(D{sup (*)}) = {Beta}({bar B} {yields} D{sup (*)}{tau}{sup -}{bar {nu}}{sub {tau}})/{Beta}({bar B} {yields} D{sup (*)}{ell}{sup -}{bar {nu}}{sub {ell}}) is presented. Here D{sup (*)} refers to a D or a D* meson and {ell} is either e or {mu}. The results, R(D) = 0.440 {+-} 0.058 {+-} 0.042 and R(D*) = 0.332 {+-} 0.024 {+-} 0.018, exceed the Standard Model expectations by 2.0{sigma} and 2.7{sigma}, respectively. Taken together, they disagree with these expectations at the 3.4{sigma} level. The excess of events cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.

  15. Effects of different heat treatments on lysozyme quantity and antimicrobial activity of jenny milk.

    Cosentino, C; Labella, C; Elshafie, H S; Camele, I; Musto, M; Paolino, R; D'Adamo, C; Freschi, P

    2016-07-01

    Thermal treatments are used to improve milk microbial safety, shelf life, and biological activity of some of its components. However, thermal treatments can reduce the nutritional quality of milk, affecting the molecular structure of milk proteins, such as lysozyme, which is a very important milk component due to its antimicrobial effect against gram-positive bacteria. Jenny milk is characterized by high lysozyme content. For this reason, in the last few years, it has been used as an antimicrobial additive in dairy products as an alternative to hen egg white lysozyme, which can cause allergic reactions. This study aimed to investigate the effect of pasteurization and condensation on the concentration and antimicrobial activity of lysozyme in jenny milk. Furthermore, lysozyme quantity and activity were tested in raw and pasteurized milk after condensation at 40 and 20% of the initial volume. Reversed-phase HPLC was performed under fluorescence detection to monitor lysozyme in milk samples. We evaluated the antimicrobial activity of the tested milk against Bacillus megaterium, Bacillus mojavensis, Clavibacter michiganensis, Clostridium tyrobutyricum, Xanthomonas campestris, and Escherichia coli. Condensation and pasteurization did not affect the concentration or antimicrobial activity of lysozyme in jenny milk, except for B. mojaventis, which showed resistance to lysozyme in milk samples subjected to heat treatments. Moreover, lysozyme in jenny milk showed antimicrobial activity similar to synthetic antibiotics versus some gram-positive strains and also versus the gram-negative strain X. campestris. PMID:27157571

  16. Low effective activation energies for oxygen release from metal oxides: evidence for mass-transfer limits at high heating rates.

    Jian, Guoqiang; Zhou, Lei; Piekiel, Nicholas W; Zachariah, Michael R

    2014-06-01

    Oxygen release from metal oxides at high temperatures is relevant to many thermally activated chemical processes, including chemical-looping combustion, solar thermochemical cycles and energetic thermite reactions. In this study, we evaluated the thermal decomposition of nanosized metal oxides under rapid heating (~10(5) K s(-1)) with time-resolved mass spectrometry. We found that the effective activation-energy values that were obtained using the Flynn-Wall-Ozawa isoconversional method are much lower than the values found at low heating rates, indicating that oxygen transport might be rate-determining at a high heating rate. PMID:24619858

  17. A new detector to measure γ and β decay power from radionuclides

    Pillon, M.; Angelone, M.; Forrest, R. A.

    2001-04-01

    Neutron activation of structural materials gives rise to an energy release during the subsequent radioactive decay. In large devices for energy production like a fission reactor, the future proposed Energy Amplifier or a Fusion power plant, this energy release represents a source of heat, which although at a very much lower level than the heating during operations is of the order of MWs for large nuclear power plants. Accurate estimation of the decay power is essential for safety analyses of the power plant against loss of coolant accidents, etc. Some computer codes have been developed to predict the decay power, but validation of the computer codes through experimental measurements is essential. A new large, almost 4π detector, formed by coupling a well-type CsI scintillator and a small plastic β detector has been developed for accurate and efficient measurements of decay power from γ and β radiation. Preliminary measurements of decay power produced in neutron-activated tungsten are presented and compared with the predictions of the European Activation Code System, EASY-99.

  18. Decay of Hoyle state

    S Bhattacharya; T K Rana; C Bhattacharya; S Kundu; K Banerjee; T K Ghosh; G Mukherjee; R Pandey; P Roy

    2014-11-01

    The prediction of Hoyle state was necessitated to explain the abundance of carbon, which is crucial for the existence of life on Earth and is the stepping stone for understanding the abundance of other heavier elements. After the experimental confirmation of its existence, soon it was realized that the Hoyle state was `different’ from other excited states of carbon, which led to intense theoretical and experimental activities over the past few decades to understand its structure. In recent times, precision, high statistics experiments on the decay of Hoyle state have been performed at the Variable Energy Cyclotron Centre, to determine the quantitative contributions of various direct 3 decay mechanisms of the Hoyle state. The present results have been critically compared with those obtained in other recent experiments and their implications have been discussed.

  19. Decay constants in geochronology

    IgorM.Villa; PaulR.Renne

    2005-01-01

    Geologic time is fundamental to the Earth Sciences, and progress in many disciplines depends critically on our ability to measure time with increasing accuracy and precision. Isotopic geochronology makes use of the decay of radioactive nuclides as a help to quantify the histories of rock, minerals, and other materials. Both accuracy and precision of radioisotopic ages are, at present, limited by those of radioactive decay constants. Modem mass spectrometers can measure isotope ratios with a precision of 10-4 or better. On the other hand, the uncertainties associated with direct half-life determinations are, in most cases, still at the percent level. The present short note briefly summarizes progress and problems that have been encountered during the Working Group's activity.

  20. Recurrent Heat Stroke in a Runner: Race Simulation Testing for Return to Activity.

    Roberts, William O; Dorman, Jason C; Bergeron, Michael F

    2016-05-01

    Exertional heat stroke (EHS) occurs in distance runners and is a life-threatening condition. A 30-yr-old healthy recreational male distance runner (CR) collapsed at the 12-mile mark in two half marathon races 6 wk apart in fall 2009. In both episodes, CR was found on the ground confused, incoherent, sweaty, and warm to touch. The emergency medical team responded, and he was treated empirically for suspected EHS by cooling en route to the emergency department. In the emergency department, rectal temperatures were 40°C and 40.5°C for each episode, respectively. The first race start temperature was 16°C with 94% relative humidity (RH), and the second was 3°C, 75% RH. Heat tolerance test was within the normal range indicating low EHS risk. A race simulation test (environmental chamber, 25°C, 60% RH) at a treadmill pace of 10.5-12.9 km·h was stopped at 70 min coincident with a rectal temperature of 39.5°C. CR's body weight dropped 3.49 kg with an estimated sweat loss of 4.09 L and an estimated total sweat Na loss of 7610 mg. We recommended that he limit his runs to <1 h and replace salt and fluid during and (mostly) after activity, run with a partner, acclimate to heat before racing, and reduce his pace or stop at the first sign of symptoms. Race simulation testing should be considered in athletes with recurrent EHS to assist with the return-to-activity recommendation. PMID:26694842

  1. Anti-cancer activities of pH- or heat-modified pectin

    Lionel eLeclere

    2013-10-01

    Full Text Available Despite enormous efforts that have been made in the search for novel drugs and treatments, cancer continues to be a major public health problem. Moreover, the emergence of resistance to cancer chemotherapy often prevents complete remission. Researchers have thus turned to natural products mainly from plant origin to circumvent resistance. Pectin and pH- or heat-modified pectin have demonstrated chemopreventive and antitumoral activities against some aggressive and recurrent cancers. The focus of this review is to describe how pectin and modified pectin display these activities and what are the possible underlying mechanisms. The failure of conventional chemotherapy to reduce mortality as well as serious side effects makes natural products, such as pectin-derived products, ideal candidates for exerting synergism in combination with conventional anticancer drugs.

  2. Management of the endoplasmic reticulum stress by activation of the heat shock response in yeast

    Hou, Jin; Tang, Hongting; Liu, Zihe;

    2014-01-01

    In yeast Saccharomyces cerevisiae, accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates the unfolded protein response (UPR), which is mediated by Hac1p. The heat shock response (HSR) mediated by Hsf1p, mainly regulates cytosolic processes and protects......-wide transcriptional response in order to propose regulatory mechanisms that govern the interplay between UPR and HSR and followed up for the hypotheses by experiments in vivo and in vitro. Interestingly, we found that the regulation of ER stress response via HSR is (1) only partially dependent on over-expression of...... Kar2p (ER resident chaperone induced by ER stress); (2) does not involve the increase in protein turnover via the proteasome activity; (3) is related to the oxidative stress response. From the transcription data, we also propose that HSR enhances ER stress resistance mainly through facilitation of...

  3. AGN activity and IGM heating in fossil cluster RX J1416.4+2315

    Miraghaei, H; Sengupta, C; Raychaudhury, S; Jetha, N N; Abbassi, S

    2015-01-01

    We study Active Galactic Nucleus (AGN) activity in the fossil galaxy cluster, RX J1416.4+2315. Radio observations were carried out using Giant Metrewave Radio Telescope (GMRT) at two frequencies, 1420 MHz and 610 MHz. A weak radio lobe that extends from the central nucleus is detected in 610 MHz map. Assuming the radio lobe originated from the central AGN, we show the energy injection into the Inter Galactic Medium (IGM) is only sufficient to heat up the central 50 kpc within the cluster core, while the cooling radius is larger ( $\\sim$ 130 kpc). In the hardness ratio map, three low energy cavities have been identified. No radio emission is detected for these regions. We evaluated the power required to inflate the cavities and showed that the total energy budget is sufficient to offset the radiative cooling. We showed that the initial conditions would change the results remarkably. Furthermore, efficiency of Bondi accretion to power the AGN has been estimated.

  4. Self-folding origami: shape memory composites activated by uniform heating

    Self-folding is an approach used frequently in nature for the efficient fabrication of structures, but is seldom used in engineered systems. Here, self-folding origami are presented, which consist of shape memory composites that are activated with uniform heating in an oven. These composites are rapidly fabricated using inexpensive materials and tools. The folding mechanism based on the in-plane contraction of a sheet of shape memory polymer is modeled, and parameters for the design of composites that self-fold into target shapes are characterized. Four self-folding shapes are demonstrated: a cube, an icosahedron, a flower, and a Miura pattern; each of which is activated in an oven in less than 4 min. Self-sealing is also investigated using hot melt adhesive, and the resulting structures are found to bear up to twice the load of unsealed structures. (paper)

  5. Simulation of heat and mass transfer in activated carbon tank for hydrogen storage

    Xiao, Jinsheng [School of Automotive Engineering, Wuhan University of Technology, Hubei 430070 (China); State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing, Wuhan University of Technology, Hubei 430070 (China); Hydrogen Research Institute, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC G9A 5H7 (Canada); Tong, Liang [School of Automotive Engineering, Wuhan University of Technology, Hubei 430070 (China); Department of Mechanical and Automotive Engineering, Huaxia College, Wuhan University of Technology, Hubei 430070 (China); Deng, Caihua [School of Automotive Engineering, Wuhan University of Technology, Hubei 430070 (China); Benard, Pierre; Chahine, Richard [Hydrogen Research Institute, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC G9A 5H7 (Canada)

    2010-08-15

    The charging process of hydrogen storage tank based on bed of activated carbon in a steel container at room temperature (295 K) and medium storage pressure (10 MPa) is simulated with an axisymmetric geometry model using the finite volume commercial solver Fluent. The mass flux profile at the entrance is established using user-defined functions (UDFs). The heat and mass transfer processes in the cylindrical steel tank packed with activated carbon are discussed considering the influence of viscous resistance and inertial resistance of the porous media. The velocity distribution and its effect on the temperature distribution are analyzed. The effects of the flow rate at the inlet and of the adsorption factor on the charging process are studied. A computational fluid dynamics (CFD) approach based on finite volume simulations is used. Results show that the temperature near the bottom of the tank is higher than that at the entrance, temperature in the center of the tank is higher than that near the wall and rises somewhat faster along the axial compared to the radial direction. The highest hydrogen absolute adsorption occurs at the entrance of the tank. A good agreement is found between the simulation results and the available experimental data. The maximum magnitude of the axial velocity is much higher than that of the radial component, resulting in more heat energy transfer along the axial direction than radial direction. In addition, the pressure reaches equilibrium earlier when the mass flow is higher, and the temperature reaches a maximum value faster. (author)

  6. Catharanthus roseus mitogen-activated protein kinase 3 confers UV and heat tolerance to Saccharomyces cerevisiae

    Raina, Susheel Kumar; Wankhede, Dhammaprakash Pandhari; Sinha, Alok Krishna

    2013-01-01

    Catharanthus roseus is an important source of pharmaceutically important Monoterpenoid Indole Alkaloids (MIAs). Accumulation of many of the MIAs is induced in response to abiotic stresses such as wound, ultra violet (UV) irradiations, etc. Recently, we have demonstrated a possible role of CrMPK3, a C. roseus mitogen-activated protein kinase in stress-induced accumulation of a few MIAs. Here, we extend our findings using Saccharomyces cerevisiae to investigate the role of CrMPK3 in giving tolerance to abiotic stresses. Yeast cells transformed with CrMPK3 was found to show enhanced tolerance to UV and heat stress. Comparison of CrMPK3 and SLT2, a MAPK from yeast shows high-sequence identity particularly at conserved domains. Additionally, heat stress is also shown to activate a 43 kDa MAP kinase, possibly CrMPK3 in C. roseus leaves. These findings indicate the role of CrMPK3 in stress-induced MIA accumulation as well as in stress tolerance. PMID:23221751

  7. Plasma hyperosmolality elevates the internal temperature threshold for active thermoregulatory vasodilation during heat stress in humans.

    Shibasaki, Manabu; Aoki, Ken; Morimoto, Keiko; Johnson, John M; Takamata, Akira

    2009-12-01

    Plasma hyperosmolality delays the response in skin blood flow to heat stress by elevating the internal temperature threshold for cutaneous vasodilation. This elevation could be because of a delayed onset of cutaneous active vasodilation and/or to persistent cutaneous active vasoconstriction. Seven healthy men were infused with either hypertonic (3% NaCl) or isotonic (0.9% NaCl) saline and passively heated by immersing their lower legs in 42 degrees C water for 60 min (room temperature, 28 degrees C; relative humidity, 40%). Skin blood flow was monitored via laser-Doppler flowmetry at sites pretreated with bretylium tosylate (BT) to block sympathetic vasoconstriction selectively and at adjacent control sites. Plasma osmolality was increased by approximately 13 mosmol/kgH(2)O following hypertonic saline infusion and was unchanged following isotonic saline infusion. The esophageal temperature (T(es)) threshold for cutaneous vasodilation at untreated sites was significantly elevated in the hyperosmotic state (37.73 +/- 0.11 degrees C) relative to the isosmotic state (36.63 +/- 0.12 degrees C, P < 0.001). A similar elevation of the T(es) threshold for cutaneous vasodilation was observed between osmotic conditions at the BT-treated sites (37.74 +/- 0.18 vs. 36.67 +/- 0.07 degrees C, P < 0.001) as well as sweating. These results suggest that the hyperosmotically induced elevation of the internal temperature threshold for cutaneous vasodilation is due primarily to an elevation in the internal temperature threshold for the onset of active vasodilation, and not to an enhancement of vasoconstrictor activity. PMID:19812357

  8. Activated corrosion products in ITER first wall and shielding blanket heat transfer system

    Corrosion and erosion phenomena play an important role in mobilizing activated materials in fusion machines. This paper deals with the assessment of the activated corrosion products (ACPs) related to the primary heat transfer system (PHTS) of the first wall/shielding blanket (FW/SB) of the ITER plant. ACPs could be a cause for concern in terms of occupational radiation exposure (ORE) in maintenance scenarios. They could also be relevant in the case of severe accidents, such as ex-vessel LOCAs. The assessment mainly refers to the TAC-4 design developed for ITER. The mobilization of the activated material has been estimated with the qualified CEA code PACTOLE. It considers all the chemical and physical phenomena responsible for corrosion, activation and transport of corrosion products in cooling loops. The XSDNRPM-S code is used for neutronic calculations; the ANITA-2 code for activation calculations. The results obtained show the improvement gained, in terms of corrosion and radioactive inventory reduction, by avoiding the use of the boron as additive. Results obtained point out the impact of the main water chemistry parameters (e.g., water temperature and pH) on ACP production, transport and deposition. A parametric comparison has been carried out considering the coolant flowing during dwell periods, two different in-vessel FW/SB AISI 316L compositions and two fluences: 0.3 and 3 MW·y/m2

  9. Heat Shock Protein-70 Expression in Vitiligo and its Relation to the Disease Activity

    Doss, Reham William; El-Rifaie, Abdel-Aziz A; Abdel-Wahab, Amr M; Gohary, Yasser M; Rashed, Laila A

    2016-01-01

    Background: Vitiligo is a progressive depigmenting disorder characterized by the loss of functional melanocytes from the epidermis. The etiopathogenesis of vitiligo is still unclear. Heat shock proteins (HSPs) are prime candidates to connect stress to the skin. HSPs were found to be implicated in autoimmune diseases such as rheumatoid arthritis and other skin disorders as psoriasis. Aim and Objectives: The aim of this study was to map the level of HSP-70 in vitiligo lesions to declare its role in the pathogenesis and activity of vitiligo. Materials and Methods: The study included thirty patients with vitiligo and 30 age- and sex-matched healthy controls. Vitiligo patients were divided as regards to the disease activity into highly active, moderately active, and inactive vitiligo groups. Skin biopsies were taken from the lesional and nonlesional skin of patients and from the normal skin of the controls. HSP-70 messenger RNA (mRNA) expression was estimated using quantitative real-time polymerase chain reaction. Results: Our analysis revealed a significantly higher expression of HSP-70 mRNA in lesional skin biopsies from vitiligo patients compared to nonlesional skin biopsies from vitiligo patients (P vitiligo showed higher mean HSP-70 level compared to those with inactive disease. Conclusions: HSP-70 plays a role in the pathogenesis of vitiligo and may enhance the immune response in active disease.

  10. Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003; Programme 'Solaire actif - Chaleur et Stockage de chaleur'. Activites et projets en 2003

    Hadorn, J.-C. [Base Consultants, Geneva (Switzerland); Renaud, P. [Planair SA, La Sagne (Switzerland)

    2003-07-01

    In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD

  11. Radioactive decay data tables

    The estimation of radiation dose to man from either external or internal exposure to radionuclides requires a knowledge of the energies and intensities of the atomic and nuclear radiations emitted during the radioactive decay process. The availability of evaluated decay data for the large number of radionuclides of interest is thus of fundamental importance for radiation dosimetry. This handbook contains a compilation of decay data for approximately 500 radionuclides. These data constitute an evaluated data file constructed for use in the radiological assessment activities of the Technology Assessments Section of the Health and Safety Research Division at Oak Ridge National Laboratory. The radionuclides selected for this handbook include those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in nuclear medicine and fusion reactor technology, and some of those of interest to Committee 2 of the International Commission on Radiological Protection for the estimation of annual limits on intake via inhalation and ingestion for occupationally exposed individuals

  12. Coatings of active and heat-resistant cobalt-aluminium xerogel catalysts.

    Schubert, Miriam; Schubert, Lennart; Thomé, Andreas; Kiewidt, Lars; Rosebrock, Christopher; Thöming, Jorg; Roessner, Frank; Bäumer, Marcus

    2016-09-01

    The application of catalytically coated metallic foams in catalytic processes has a high potential for exothermic catalytic reactions such as CO2 methanation or Fischer-Tropsch synthesis due to good heat conductivity, improved turbulent flow properties and high catalyst efficiencies. But the preparation of homogenous catalyst coats without pore blocking is challenging with conventional wash coating techniques. Here, we report on a stable and additive free colloidal CoAlOOH suspension (sol) for the preparation of catalytically active Co/Al2O3 xerogel catalysts and coatings. Powders with 18wt% Co3O4 prepared from this additive free synthesis route show a catalytic activity in Fischer-Tropsch synthesis and CO2 methanation which is similar to a catalyst prepared by incipient wetness impregnation (IWI) after activating the material under flowing hydrogen at 430°C. Yet, the xerogel catalyst exhibits a much higher thermal stability as compared to the IWI catalyst, as demonstrated in catalytic tests after different heat agings between 430°C and 580°C. It was also found that the addition of polyethylene glycol (PEG) to the sol influences the catalytic properties of the formed xerogels negatively. Only non-reducible cobalt spinels were formed from a CoAlOOH sol with 20wt% PEG. Metallic foams with pores sizes between 450 and 1200μm were coated with the additive free CoAlOOH sol, which resulted in homogenous xerogel layers. First catalytic tests of the coated metal foams (1200μm) showed good performance in CO2 methanation. PMID:27240245

  13. A sexual dimorphism influences bicyclol-induced hepatic heat shock factor 1 activation and hepatoprotection.

    Chen, Xiaosong; Zhang, Jianjian; Han, Conghui; Dai, Huijuan; Kong, Xianming; Xu, Longmei; Xia, Qiang; Zhang, Ming; Zhang, Jianjun

    2015-07-01

    Bicyclol [4,4'-dimethoxy-5,6,5',6'-bis(methylenedioxy)-2-hydroxy-methyl-2'-methoxycarbonyl biphenyl] is a synthetic hepatoprotectant widely used in clinical practice, but resistance to this treatment is often observed. We found that the hepatoprotective effect of bicyclol was greatly compromised in female and castrated male mice. This study was to dissect the molecular basis behind the sex difference, which might underlie the clinical uncertainty. We compared bicyclol-induced hepatoprotection between male and female mice using acute liver damage models. Inducible knockout by the Cre/loxp system was used to decipher the role of heat shock transcription factor 1 (HSF1). Functional experiments, western blot, and histopathological analysis were used to determine the key causative factors which might antagonize bicyclol in female livers. HSF1 activation and heat shock protein 70 (Hsp70) expression, which were responsible for bicyclol-induced hepatoprotection, were compromised in female and castrated male livers. Compromised HSF1 activation was a result of HSF1 phosphorylation at serine 303, which was catalyzed by glycogen synthase kinase 3β (GSK3β). Testosterone was necessary for bicyclol to inhibit hepatic GSK3β activity. Administration of testosterone or GSK3β inhibitors restored bicyclol-induced protection in females. Bicyclol induces sex-specific hepatoprotection based on a sex-specific HSF1/Hsp70 response, in which testosterone and GSK3β play key roles. Because a lot of patients suffering from liver diseases have very low testosterone levels, our results give a possible explanation for the clinical variation in bicyclol-induced hepatoprotection, as well as practicable solutions to improve the effect of bicyclol. PMID:25901028

  14. ISOTROPIC HEATING OF GALAXY CLUSTER CORES VIA RAPIDLY REORIENTING ACTIVE GALACTIC NUCLEUS JETS

    Active galactic nucleus (AGN) jets carry more than sufficient energy to stave off catastrophic cooling of the intracluster medium (ICM) in the cores of cool-core clusters. However, in order to prevent catastrophic cooling, the ICM must be heated in a near-isotropic fashion and narrow bipolar jets with Pjet = 1044–45 erg s–1, typical of radio AGNs at cluster centers, are inefficient in heating the gas in the transverse direction to the jets. We argue that due to existent conditions in cluster cores, the supermassive black holes (SMBHs) will, in addition to accreting gas via radiatively inefficient flows, experience short stochastic episodes of enhanced accretion via thin disks. In general, the orientation of these accretion disks will be misaligned with the spin axis of the black holes (BHs) and the ensuing torques will cause the BH's spin axis (and therefore the jet axis) to slew and rapidly change direction. This model not only explains recent observations showing successive generations of jet-lobes-bubbles in individual cool-core clusters that are offset from each other in the angular direction with respect to the cluster center, but also shows that AGN jets can heat the cluster core nearly isotropically on the gas cooling timescale. Our model does require that the SMBHs at the centers of cool-core clusters be spinning relatively slowly. Torques from individual misaligned disks are ineffective at tilting rapidly spinning BHs by more than a few degrees. Additionally, since SMBHs that host thin accretion disks will manifest as quasars, we predict that roughly 1-2 rich clusters within z < 0.5 should have quasars at their centers.

  15. CO2 emission baseline construction for Activities Implemented Jointly reporting in heat production sector

    The present work is dedicated to the calculation method for the reduction of greenhouse gases emissions developed within the Joint Implementation projects of the Climate Change Framework Convention based on the case study of Estonian heat supply in 1990ies. Data of the Estonian Statistical Office and data of the Estonian Energy Research Institute on the use of fuels and heat production in recent decade have been used in the paper. CO2 emissions by the types of fuels have been calculated and emission reduction trend for the whole country is given based on the detailed statistics of the consumption of various fuels. This has been taken for a basis for calculating the decrease of CO2 emissions as a result of Joint Implementation pilot phase implementation between Sweden and Estonia. Baseline of CO2 emission has been constructed, considering the changes in the structure of fuel consumption as well as the forecasts of energy sector as whole. Constructed by authors of present paper baseline has been used by donor country for reporting to U N FCCC Secretariat in Bonn. Decision on credit sharing and emission trading between parties to Climate Convention has not been made yet, but Estonia and Sweden are ready for that looking forward to decisions to be made during the next conference of parties, COP 6. Authors do hope sincerely that the present contribution will elaborate to the solutions for future activities between two neighbours. (author)

  16. Simulation Research on Decay Heat Removal System in Primary Loop of Pool-type Sodium-cooled Fast Reactor%池式钠冷快堆事故余热排出系统一回路仿真研究

    姜博; 张智刚; 于洋; 陈广亮; 张志俭

    2015-01-01

    池式钠冷快堆事故余热排出系统采用了非能动工作原理,依靠液态钠及空气的自然对流排出堆芯余热。为研究事故工况下余热排出系统一回路的换热能力,基于 FORTRAN 语言,建立堆芯单通道及盒间流模型,采用全隐二阶迎风差分格式及改进的欧拉法离散求解,对事故余热排出系统一回路系统进行数值模拟,并对全厂断电事故进行仿真计算验证。结果表明:该程序能较好地反映事故余热排出系统瞬态变化过程,并可达到超实时仿真。%T he decay heat removal system in pool‐type sodium‐cooled fast reactor (PSFR) is the passive safety system ,which depends on the natural circulation of sodium and air to keep the reactor coolant cooled .In order to verify the characteristics of the heat transfer of decay heat removal system in primary loop for accident condition ,the core single‐channel model and the flow between fuel assemblies model were established to simulate the decay heat removal system of primary loop and testify the program on station blackout accident , by using fully‐implicit second‐order upwind scheme and ameliorative Eular method to solve the equations based on FORTRAN .The calculation results show that the program could reflect the transient characteristics of the decay heat removal system ,and it could reach excess real‐time simulation .

  17. Adsorption characteristics and heat of adsorption measurements of R-134a on activated carbon

    Saha, Bidyut B. [Mechanical Engineering Department, National University of Singapore, 10 Kent Ridge Crescent (Singapore); Habib, Khairul; Koyama, Shigeru [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga-shi, Fukuoka 816-8580 (Japan); El-Sharkawy, Ibrahim I. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga-shi, Fukuoka 816-8580 (Japan); Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, El-Mansoura (Egypt)

    2009-11-15

    This paper presents adsorption isotherms of R-134a (HFC-134a) on highly porous pitch based activated carbon (Maxsorb III) in the temperature range of 5-70 C and pressures up to 12 bar, using desorption method. The experimental data have been fitted with the Dubinin-Astakhov (D-A) isotherm equation. The adsorption isotherms of R-134a on Maxsorb III obtained from the present study are compared with the adsorption isotherm results of R-134a on similar type of adsorbents obtained by other researchers and they are found to be fairly consistent. The isosteric heat of adsorption of the assorted adsorbent-refrigerant pair has also been extracted from the present experimental data. (author)

  18. Thermodynamic assessment of active cooling/heating methods for lithium-ion batteries of electric vehicles in extreme conditions

    The battery cooling/heating with active methods is required for EVs (electric vehicles) in the extreme temperature conditions. This work presents a new active battery cooling/heating method based on PCS (phase change slurry) cycle. Two typical often used active cooling/heating methods so-called the direct cabin air blow and refrigerant circulation are also illustrated in detail. The thermodynamic assessment is conducted on these battery active cooling/heating methods with both of 1st Law and 2nd Law analysis. The variations of extra thermal load to the vehicle air-conditioning system are investigated as changes of ambient temperature, humidity and thermal load for the direct cabin air blow method. The simulation results show that the direct cabin air blow method causes more extra thermal load to the air-conditioning system without considering the cabin ventilation effect. The PCS cycle method performs higher exergy efficiency than that of using refrigerant circulation method. - Highlights: • An active EV battery cooling/heating method based on PCS cycle is proposed. • Thermodynamic assessments are performed for the proposed methods. • The sensitivities of operation conditions to the methods are investigated

  19. Impacts of decaying eastern and central Pacific El Niños on tropical cyclone activities over the western North Pacific in summer

    Yang, Yuxing; Xie, Ruihuang; Wang, Faming; Huang, Fei

    2016-07-01

    We investigate the influences of the decaying eastern Pacific El Niño (EP-El Niño) and central Pacific El Niño (CP-El Niño) on tropical cyclone (TC) activities in the western North Pacific (WNP) during July, August, and September (JAS). During this period, TC geneses and tracks are reduced in the central and eastern WNP. However, TC tracks reaching the Philippines increase, and more TC geneses appear west of 145°E during EP-El Niño. During CP-El Niño, tracks reaching the South China Sea (SCS) and southeast coast of China increase, and positive anomalies of TC genesis are found in the southern part of the central WNP and southern SCS. It is possible that the different variations of the anomalous anticyclone over east of the Philippines in the WNP induced by El Niños are instrumental to the different TC variations in the two types of decaying El Niños during JAS. Compared with EP-El Niño, strengthening and northward expansion of the anomalous anticyclone during CP-El Niño cause a westward shift of the western Pacific subtropical high in summer, which is responsible for more westward TC tracks over the SCS and southeast coast of China. This northward expansion can cause the center of suppressed TC geneses in the central WNP to migrate further north during CP-El Niño. A decreased magnitude of vertical shear dominates the southern part of the central WNP and southern SCS, which enhances TC formation in these regions during CP-El Niño.

  20. Impacts of decaying eastern and central Pacific El Niños on tropical cyclone activities over the western North Pacific in summer

    Yang, Yuxing; Xie, Ruihuang; Wang, Faming; Huang, Fei

    2015-05-01

    We investigate the influences of the decaying eastern Pacific El Niño (EP-El Niño) and central Pacific El Niño (CP-El Niño) on tropical cyclone (TC) activities in the western North Pacific (WNP) during July, August, and September (JAS). During this period, TC geneses and tracks are reduced in the central and eastern WNP. However, TC tracks reaching the Philippines increase, and more TC geneses appear west of 145°E during EP-El Niño. During CP-El Niño, tracks reaching the South China Sea (SCS) and southeast coast of China increase, and positive anomalies of TC genesis are found in the southern part of the central WNP and southern SCS. It is possible that the different variations of the anomalous anticyclone over east of the Philippines in the WNP induced by El Niños are instrumental to the different TC variations in the two types of decaying El Niños during JAS. Compared with EP-El Niño, strengthening and northward expansion of the anomalous anticyclone during CP-El Niño cause a westward shift of the western Pacific subtropical high in summer, which is responsible for more westward TC tracks over the SCS and southeast coast of China. This northward expansion can cause the center of suppressed TC geneses in the central WNP to migrate further north during CP-El Niño. A decreased magnitude of vertical shear dominates the southern part of the central WNP and southern SCS, which enhances TC formation in these regions during CP-El Niño.

  1. Regional Heat Sources and the Active and Break Phases of Boreal Summer Intraseasonal Variability

    Annamalai, H; Sperber, K R

    2003-12-15

    The boreal summer intraseasonal variability (BSISV) associated with the 30-50 day mode is represented by the co-existence of three components, poleward propagation of convection over the Indian and tropical west Pacific longitudes and eastward propagation along the equator. The hypothesis that the three components influence each other has been investigated using observed OLR, NCEP-NCAR reanalysis, and solutions from an idealized linear model. The null hypothesis is that the three components are mutually independent. Cyclostationary EOF (CsEOF) analysis is applied on filtered OLR to extract the life-cycle of the BSISV. The dominant mode of CsEOF is significantly tied to observed rainfall over the Indian subcontinent. The components of the heating patterns from CsEOF analysis serve as prescribed forcings for the linear model. This allows us to ascertain which heat sources and sinks are instrumental in driving the large-scale monsoon circulation during the BSISV life-cycle. We identify three new findings: (1) the circulation anomalies that develop as a Rossby wave response to suppressed convection over the equatorial Indian Ocean associated with the previous break phase of the BSISV precondition the ocean-atmosphere system in the western Indian Ocean and trigger the next active phase of the BSISV, (2) the development of convection over the tropical west Pacific forces descent anomalies to the west. This, in conjunction with the weakened cross-equatorial flow due to suppressed convective anomalies over the equatorial Indian Ocean reduce the tropospheric moisture over the Arabian Sea, and promote westerly wind anomalies that do not recurve over India. As a result the low-level cyclonic vorticity shifts from India to southeast Asia and break conditions are initiated over India, and (3) the circulation anomalies forced by equatorial Indian Ocean convective anomalies significantly influence the active/break phases over the tropical west Pacific. Our model solutions support

  2. A practical cooling strategy for reducing the physiological strain associated with firefighting activity in the heat.

    Barr, D; Gregson, W; Sutton, L; Reilly, T

    2009-04-01

    The aim of this study was to establish whether a practical cooling strategy reduces the physiological strain during simulated firefighting activity in the heat. On two separate occasions under high ambient temperatures (49.6 +/- 1.8 degrees C, relative humidity (RH) 13 +/- 2%), nine male firefighters wearing protective clothing completed two 20-min bouts of treadmill walking (5 km/h, 7.5% gradient) separated by a 15-min recovery period, during which firefighters were either cooled (cool) via application of an ice vest and hand and forearm water immersion ( approximately 19 degrees C) or remained seated without cooling (control). There was no significant difference between trials in any of the dependent variables during the first bout of exercise. Core body temperature (37.72 +/- 0.34 vs. 38.21 +/- 0.17 degrees C), heart rate (HR) (81 +/- 9 vs. 96 +/- 17 beats/min) and mean skin temperature (31.22 +/- 1.04 degrees C vs. 33.31 +/- 1 degrees C) were significantly lower following the recovery period in cool compared with control (p second bout of activity in cool compared to control. Mean skin temperature, HR and thermal sensation were significantly lower during bout 2 in cool compared with control (p < 0.05). It is concluded that this practical cooling strategy is effective at reducing the physiological strain associated with demanding firefighting activity under high ambient temperatures. PMID:19401892

  3. The heat shock protein 90 of Plasmodium falciparum and antimalarial activity of its inhibitor, geldanamycin

    Barik Sailen

    2003-09-01

    Full Text Available Abstract Background The naturally occurring benzoquinone ansamycin compound, geldanamycin (GA, is a specific inhibitor of heat shock protein 90 (Hsp90 and is a potential anticancer agent. Since Plasmodium falciparum has been reported to have an Hsp90 ortholog, we tested the possibility that GA might inhibit it and thereby display antiparasitic activity. Results We provide direct recombinant DNA evidence for the Hsp90 protein of Plasmodium falciparum, the causative agent of fatal malaria. While the mRNA of Hsp90 was mainly expressed in ring and trophozoite stages, the protein was found in all stages, although schizonts contained relatively lower amounts. In vitro the parasitic Hsp90 exhibited an ATP-binding activity that could be specifically inhibited by GA. Plasmodium growth in human erythrocyte culture was strongly inhibited by GA with an IC50 of 20 nM, compared to the IC50 of 15 nM for chloroquine (CQ under identical conditions. When used in combination, the two drugs acted synergistically. GA was equally effective against CQ-sensitive and CQ-resistant strains (3D7 and W2, respectively and on all erythrocytic stages of the parasite. Conclusions Together, these results suggest that an active and essential Hsp90 chaperone cycle exists in Plasmodium and that the ansamycin antibiotics will be an important tool to dissect its role in the parasite. Additionally, the favorable pharmacology of GA, reported in human trials, makes it a promising antimalarial drug.

  4. The effects of Sao Paulo urban heat island on lightning activity: Decadal analysis (1999-2009)

    Bourscheidt, Vandoir; Pinto, Osmar; Naccarato, Kleber P.

    2016-05-01

    Eleven years of lightning data from the Brazilian Integrated National Lightning Detection Network were used to analyze the effects of the urban heat island (UHI) of Sao Paulo on lightning activity, extending the investigation of previous works. Cloud-to-ground lightning data were analyzed in both spatial and temporal perspectives, using different approaches: flash density, flash rate, thunderstorm hours (TH), and the cell initiation technique (CIT), which aims to identify the onset of thunderstorms. Land surface temperature (LST) from MODIS (Moderate Resolution Imaging Spectroradiometer) was used to analyze the UHI evolution over the years. MODIS data were validated using ground stations, distributed within the urban area. Different time intervals (seasonal and intraday) were used in an attempt to separate local convective systems from synoptic-scale events. The results indicate significant effects of the UHI (using LST) on THs and CIT. The CIT showed a nearly ring pattern, especially during the afternoon (14:00-18:00 LT) of summer months, reinforcing temperature contrast as a condition for storm initiation. The results also suggest an amplification of the UHI effects on thunderstorm activity by local factors (sea and country breeze, synoptic events, and terrain). Higher flash rates were also observed throughout the urban region, which influences the lightning density. Temporal analysis indicates that minimum temperature and lightning activity increase in wintertime. In summary, the results agree with previous studies about the UHI and indicate its importance on lightning occurrence, especially by increasing the temperature contrast and the instability in these regions.

  5. Heating of dust in the broad-line regions of active galaxies and quasars

    In this paper we discuss the relevant energy sources which heat (and, in many cases, destroy) the dust grains in the emission-line clouds (ELCs) which give rise to the broad-line emission seen in active extragalactic objects. We compare the heating rates from the external radiation field, trapped line radiation, and the diffuse bound-free continua. We find that in hot clouds (T/sub e/ = 1.5 x 104 K) Lyα dominates the dust heating rate, while in cooler clouds (T/sub e/ = 1.0 x 104 K) the external radiation field dominates. In all cases, the dust residing in the broad-line clouds is quite hot (T>500 K). These results are discussed in light of the observed infrared properties of active galaxies and quasars, and the following conclusions are reached: (1) If the infrared emission of Seyfert 1 galaxies is primarily thermal in origin, then the redder near-IR colors distinguishing the Seyfert 1 galaxies from the Seyfert 2 galaxies may be understood in terms of the broad-line regions (BLR) concentrating hot dust within the inner parsec of the of the nucleus. (2) Substantial near-infrared dust emission may originate in the neutral regions of the ELCs with only minor accompanying reddening of the hydrogen Balmer lines, since dust confined to the neutral zone reddens only lines emitted from the back side of the cloud. (3) If the broad-line regions of the quasars are characterized by hotter temperatures than Seyfert 1 galaxies, dust may not be able to exist in this region, thereby explaining the apparent lack of thermal dust emission in quasars. (4) Because of the cooling times of the ELCs, near-IR variability due to changes in the dust temperature is dominated by light travel considerations. (5) The present calculations suggest that the dust-to-gas mass ratio in the BLRs of Seyfert 1 galaxies is substantially smaller than the value of 0.01 typically found in our Galaxy

  6. Modulating the RNA processing and decay by the exosome: altering Rrp44/Dis3 activity and end-product.

    Filipa P Reis

    Full Text Available In eukaryotes, the exosome plays a central role in RNA maturation, turnover, and quality control. In Saccharomyces cerevisiae, the core exosome is composed of nine catalytically inactive subunits constituting a ring structure and the active nuclease Rrp44, also known as Dis3. Rrp44 is a member of the ribonuclease II superfamily of exoribonucleases which include RNase R, Dis3L1 and Dis3L2. In this work we have functionally characterized three residues located in the highly conserved RNB catalytic domain of Rrp44: Y595, Q892 and G895. To address their precise role in Rrp44 activity, we have constructed Rrp44 mutants and compared their activity to the wild-type Rrp44. When we mutated residue Q892 and tested its activity in vitro, the enzyme became slightly more active. We also showed that when we mutated Y595, the final degradation product of Rrp44 changed from 4 to 5 nucleotides. This result confirms that this residue is responsible for the stacking of the RNA substrate in the catalytic cavity, as was predicted from the structure of Rrp44. Furthermore, we also show that a strain with a mutation in this residue has a growth defect and affects RNA processing and degradation. These results lead us to hypothesize that this residue has an important biological role. Molecular dynamics modeling of these Rrp44 mutants and the wild-type enzyme showed changes that extended beyond the mutated residues and helped to explain these results.

  7. Bubble chamber: Omega production and decay

    1973-01-01

    This image is taken from one of CERN's bubble chambers and shows the decay of a positive kaon in flight. The decay products of this kaon can be seen spiraling in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that has been heated to boiling point.

  8. Weak decays of strongly decaying mesons

    Weak decays of the light mesons η, η', ρ, ω and κ* are considered. It is pointed out that a measurement of the decays η' → κπ, ρ → π, ω → κπ and κ* → ππ is within reach at LEAR. This would give valuable information on the mechanism behind the ΔI = 1/2 rule in weak nonleptonic decays. A possible strangeness asymmetry in these decays is proposed as a manifestation of CP violation. However, this asymmetry is estimated in the standard electroweak model to be too minute to be measurable at present. (orig.)

  9. Horizontal flow fields in and around a small active region-- The transition period between flux emergence and decay

    Verma, M; Balthasar, H; Kuckein, C; Manrique, S J González; Sobotka, M; González, N Bello; Hoch, S; Diercke, A; Kummerow, P; Berkefeld, T; Collados, M; Feller, A; Hofmann, A; Kneer, F; Lagg, A; Löhner-Böttcher, J; Nicklas, H; Yabar, A Pastor; Schlichenmaier, R; Schmidt, D; Schmidt, W; Schubert, M; Sigwarth, M; Solanki, S K; Soltau, D; Staude, J; Strassmeier, K G; Volkmer, R; von der Lühe, O; Waldmann, T

    2016-01-01

    Aims. Combining high-resolution and synoptic observations aims to provide a comprehensive description of flux emergence at photospheric level and of the growth process that eventually leads to a mature active region. Methods. Small active region NOAA 12118 was observed on 2014 July 18 with the 1.5-meter GREGOR solar telescope on 2014 July 18. High-resolution time-series of blue continuum and G-band images acquired in the blue imaging channel (BIC) of the GREGOR Fabry-P\\'erot Interferometer (GFPI) were complemented by LOS magnetograms and continuum images obtained with the HMI onboard the SDO. Horizontal proper motions and horizontal plasma velocities were computed with local correlation tracking (LCT) and the differential affine velocity estimator, respectively. Morphological image processing was employed to measure the photometric/magnetic area, magnetic flux, and the separation profile of the EFR during its evolution. Results. The computed growth rates for photometric area, magnetic area, and magnetic flux ...

  10. Bubble chamber: Omega production and decay

    1973-01-01

    This image is of real particle tracks taken from the CERN 2 m liquid hydrogen bubble chamber and shows the production and decay of a negative omega particle. A negative kaon enters the chamber which decays into many particles, including a negative omega that travels a short distance before decaying into more particles. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  11. Analytical studies by activation. Part A and B: Counting of short half-life radio-nuclides. Part C: Analytical programs for decay curves

    Part A and B: Since a radio-nuclide of short half-life is characterized essentially by the decrease in its activity even while it is being measured, the report begins by recalling the basic relationships linking the half-life the counting time, the counting rate and the number of particles recorded. The second part is devoted to the problem of corrections for counting losses due to the idle period of multichannel analyzers. Exact correction formulae have been drawn up for the case where the short half-life radionuclide is pure or contains only a long half-life radio-nuclide. By comparison, charts have been drawn up showing the approximations given by the so-called 'active time' counting and by the counting involving the real time associated with a measurement of the overall idle period, this latter method proving to be more valid than the former. A method is given for reducing the case of a complex mixture to that of a two-component mixture. Part C: The problems connected with the qualitative and quantitative analysis of the decay curves of a mixture of radioactive sources of which one at least has a short half-life are presented. A mathematical description is given of six basic processes for which some elements of Fortran programs are proposed. Two supplementary programs are drawn up for giving an overall treatment of problems of dosage in activation analysis: one on the basis of a simultaneous irradiation of the sample and of one or several known samples, the other with separate irradiation of the unknown and known samples, a dosimeter (activation, or external) being used for normalizing the irradiation flux conditions. (author)

  12. Surface Cleaning or Activation?Control of Surface Condition Prior to Thermo-Chemical Heat Treatment

    Brigitte Haase; Juan Dong; Jens Heinlein

    2004-01-01

    Actual heat treatment processes must face increasing specifications with reference to process quality, safety and results in terms of reproducibility and repeatability. They can be met only if the parts' surface condition is controlled during manufacturing and, especially, prior to the treatment. An electrochemical method for the detection of a steel part's surface condition is presented, together with results, consequences, and mechanisms concerning surface pre-treatment before the thermochemical process. A steel surface's activity or passivity can be detected electrochemically, independently from the chemical background. The selected method was the recording of potential vs. time curves at small constant currents, using a miniaturized electrochemical cell, a (nearly) non-destructive electrolyte and a potentio-galvanostatic setup. The method enables to distinguish types of surface contamination which do not interfere with the thermochemical process, from passive layers which do and must be removed. Whereas some types of passive layers can be removed using conventional cleaning processes and agents, others are so stable that their effects can only be overcome by applying an additional activation pre-treatment, e.g. oxynitriding.

  13. Decadal variation of ocean heat content and tropical cyclone activity over the Bay of Bengal

    Sankar Nath; S D Kotal; P K Kundu

    2016-02-01

    The upper ocean heat content up to 700 m depth (OHC700) is an important climatic parameter required for atmospheric and oceanographic studies like a cyclone. In this study, therefore, an attempt has been made to examine the inter-decadal variations of tropical cyclone (TC) activity and OHC700 over the Bay of Bengal (BOB) for the post-monsoon season (October–December) during 1955–2013 periods. The sea-surface temperature (SST), geopotential height at 500 hPa, low-level vorticity at 850 hPa, vertical wind shear between 200 and 850 hPa, middle tropospheric humidity at 500 hPa and outgoing long-wave radiation are also being studied using seasonal mean data. The results show a significant inter-decadal variation during 1955–2013, with two distinct decadal periods: active decadal period (ADP) (1955–1988) and inactive decadal period (IDP) (1989–2013). The anomalies of these parameters are opposite in phase for two periods. It is found that the large scale atmospheric features and oceanic parameters have significant inter-decadal variability, but frequency of the tropical cyclone is attributed to the variation in the atmospheric dynamic and thermodynamic conditions rather than the variation of oceanic parameters OHC700 and SSTs during the post-monsoon season.

  14. Impact of individual acid flue gas components on mercury capture by heat-treated activated carbon

    Jian-ming ZHENG; Jin-song ZHOU; Zhong-yang LUO; Ke-fa CEN

    2012-01-01

    Elemental mercury capture on heat-treated activated carbon (TAC) was studied using a laboratory-scale fixed bed reactor.The capability of TAC to perform Hg0 capture under both N2 and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components.The results suggest that surface functional groups (SFGs) on activated carbon (AC) are vital to Hg0 capture in the absence of acid gases.Meanwhile,the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg0 capture.The presence of HCl,NO2,and NO individually in basic gases markedly enhances Hg0 capture on TAC due to the heterogeneous oxidation of Hg0 on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC.Similarly,the presence of SO2 improves Hg0 capture by about 20%.This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO2 due to catalysis on the carbon surface.Furthermore,O2 exhibits a synergistic effect on Hg0 oxidation and capture when acid gases are present in the flue gases.

  15. Decadal variation of ocean heat content and tropical cyclone activity over the Bay of Bengal

    Nath, Sankar; Kotal, S. D.; Kundu, P. K.

    2016-02-01

    The upper ocean heat content up to 700 m depth (OHC700) is an important climatic parameter required for atmospheric and oceanographic studies like a cyclone. In this study, therefore, an attempt has been made to examine the inter-decadal variations of tropical cyclone (TC) activity and OHC700 over the Bay of Bengal (BOB) for the post-monsoon season (October-December) during 1955-2013 periods. The sea-surface temperature (SST), geopotential height at 500 hPa, low-level vorticity at 850 hPa, vertical wind shear between 200 and 850 hPa, middle tropospheric humidity at 500 hPa and outgoing long-wave radiation are also being studied using seasonal mean data. The results show a significant inter-decadal variation during 1955-2013, with two distinct decadal periods: active decadal period (ADP) (1955-1988) and inactive decadal period (IDP) (1989-2013). The anomalies of these parameters are opposite in phase for two periods. It is found that the large scale atmospheric features and oceanic parameters have significant inter-decadal variability, but frequency of the tropical cyclone is attributed to the variation in the atmospheric dynamic and thermodynamic conditions rather than the variation of oceanic parameters OHC700 and SSTs during the post-monsoon season.

  16. Nuclear decay processes

    Radioactive decay processes involve nuclear reactions that generally involve specific emissions from the nucleus and result in the transmutations of elements. This article discusses types of nuclear reactions according to their modes of decay. Included in the text are the following: α decay; β decay; negatron decay; positron decay; orbital electron capture; isomeric transitions. Each has a text/diagram explanation, examples, and characteristics summary. Also included are sources of nuclear and atomic data and a five problem set. 4 refs., 7 figs., 1 tab

  17. Estimation of the activity and isotopic composition of the fuel elements of the reactor in decaying; Estimacion de la actividad y composicion isotopica de los elementos combustibles del reactor en decaimiento

    Aguilar H, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2001-03-15

    At the present time its are had 59 fuel elements, 3 control bars with follower and 2 instrumented irradiated fuels that its are decaying in the pool of the reactor. The burnt one that its have these fuels is not uniform, the quantity of U-235 that contain at the moment it varies between 33.5 g up to 35.2 and its have a decay of at least 12 years. The burnt of the fuels was obtained with the CREMAT code, this burnt was takes like base to estimate the current isotopic inventory and the activity of the same ones using the ORIGEN2 code. (Author)

  18. Inference of Heating Properties from "Hot" Non-flaring Plasmas in Active Region Cores I. Single Nanoflares

    Barnes, W T; Bradshaw, S J

    2016-01-01

    The properties expected of "hot" non-flaring plasmas due to nanoflare heating in active regions are investigated using hydrodynamic modeling tools, including a two-fluid development of the EBTEL code. Here we study a single nanoflare and show that while simple models predict an emission measure distribution extending well above 10 MK that is consistent with cooling by thermal conduction, many other effects are likely to limit the existence and detectability of such plasmas. These include: differential heating between electrons and ions, ionization non-equilibrium and, for short nanoflares, the time taken for the coronal density to increase. The most useful temperature range to look for this plasma, often called the "smoking gun" of nanoflare heating, lies between $10^{6.6}$ and $10^7$ K. Signatures of the actual heating may be detectable in some instances.

  19. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... the performance of the new deck with PCM concrete is the thermal properties of such a new material, as the PCM concrete is yet to be well defined. The results presented in the paper include models in which the PCM concrete material properties, such as thermal conductivity, and specific heat capacity were first...... with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating...

  20. Apparent activation energy for densification of -Al2O3 powder at constant heating-rate sintering

    W Q Shao; S O Chen; D Li; H S Cao; Y C Zhang; S S Zhang

    2008-11-01

    The apparent activation energy for densification is a characteristic quantity that elucidates the fundamental diffusion mechanisms during the sintering process. Based on the Arrhenius theory, the activation energy for densification of -Al2O3 at constant heating-rates sintering has been estimated. Sintering of -Al2O3 powder has been executed by the way of a push rod type dilatometer. It is shown that the apparent activation energy does not have a single value but depends directly on the relative density. The apparent activation energy corresponding to lower relative density was higher than that corresponding to higher relative density. In addition, the value of the evaluated activation energy is different at the same density level when the Arrhenius plot involves different heating rates.