Preliminary calculations of release rates from spent fuel in a tuff repository
International Nuclear Information System (INIS)
Apted, M.J.; O'Connell, W.J.; Lee, K.H.; MacIntyre, A.T.; Ueng, T.S.; Pigford, T.H.; Lee, W.W.L.
1991-01-01
Time-dependent release rates of Tc-99, I-129, Cs-135, and Np-237 have been calculated for wet-drip and moist-continuous release modes from the engineered barrier system of a potential nuclear waste repository in unsaturated tuff, representative of a possible repository at Yucca Mountain in southern Nevada. We describe the modes of water contact and of release of dissolved radionuclides to the surrounding intact rock, and the corresponding calculational models. We list the parameter values adopted, and then present numerical results, conclusions, and recommendations. 21 refs., 5 figs., 2 tabs
Energy Technology Data Exchange (ETDEWEB)
HU TA
2009-10-26
Assess the steady-state flammability level at normal and off-normal ventilation conditions. The hydrogen generation rate was calculated for 177 tanks using the rate equation model. Flammability calculations based on hydrogen, ammonia, and methane were performed for 177 tanks for various scenarios.
Directory of Open Access Journals (Sweden)
Xiao Qinghua
2016-03-01
Full Text Available Based on energy theory, energy release rate (EER and local energy release rate (LEER, a new index called FERR (Fractional Energy Release Rate is proposed, and this method can not only evaluate the risk of rock burst, but also can point out the location of high risk and the scale of rockburst. The FERR index is applied to the TBM assembling tunnel in Jinping Hydro Power Station II to evaluate the scale and intensity of rockburst, as well as the location where rockburst occurs. With FDM method adopted, the energy release rate of 3 excavation plans are calculated and the scale and risk of rockburst is evaluated, and the location of high risk of rockburst is also mapped. With FERR used in the evaluation, the rockburst is nicely controlled which ensured the safety and construction schedule of the project.
Development of DUST: A computer code that calculates release rates from a LLW disposal unit
International Nuclear Information System (INIS)
Sullivan, T.M.
1992-01-01
Performance assessment of a Low-Level Waste (LLW) disposal facility begins with an estimation of the rate at which radionuclides migrate out of the facility (i.e., the disposal unit source term). The major physical processes that influence the source term are water flow, container degradation, waste form leaching, and radionuclide transport. A computer code, DUST (Disposal Unit Source Term) has been developed which incorporates these processes in a unified manner. The DUST code improves upon existing codes as it has the capability to model multiple container failure times, multiple waste form release properties, and radionuclide specific transport properties. Verification studies performed on the code are discussed
Helium release rates and ODH calculations from RHIC magnet cooling line failure
Energy Technology Data Exchange (ETDEWEB)
Liaw, C.J.; Than, Y.; Tuozzolo, J.
2011-03-28
A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.
International Nuclear Information System (INIS)
Meacham, J.E.
2008-01-01
This report assesses the steady state flammability level under off normal ventilation conditions in the tank headspace for 28 double-shell tanks (DST) and 149 single shell-tanks (SST) at the Hanford Site. Flammability was calculated using estimated gas release rates, Le Chatelier's rule, and lower flammability limits of fuels in an air mixture. This revision updates the hydrogen generation rate input data for al1 177 tanks using waste composition information from the Best Basis Inventory Detail Report (data effective as of August 4,2008). Assuming only barometric breathing, the shortest time to reach 25% of the lower flammability limit is 13 days for DSTs (i.e., tank 241-AZ-102) and 36 days for SSTs (i.e., tank 241-B-203). Assuming zero ventilation, the shortest time to reach 25% of the lower flammability limit is 12 days for DSTs (i.e., tank 241-AZ-102) and 34 days for SSTs (i.e., tank 241-B-203).
International Nuclear Information System (INIS)
Meacham, J.E.
2009-01-01
This report assesses the steady state flammability level under off normal ventilation conditions in the tank headspace for 28 double-shell tanks (DST) and 149 single shell-tanks (SST) at the Hanford Site. Flammability was calculated using estimated gas release rates, Le Chatelier's rule, and lower flammability limits of fuels in an air mixture. This revision updates the hydrogen generation rate input data for all 177 tanks using waste composition information from the Best Basis Inventory Detail Report (data effective as of August 4,2008). Assuming only barometric breathing, the shortest time to reach 25% of the lower flammability limit is 11 days for DSTs (i.e., tank 241-AZ-10l) and 36 days for SSTs (i.e., tank 241-B-203). Assuming zero ventilation, the shortest time to reach 25% of the lower flammability limit is 10 days for DSTs (i.e., tank 241-AZ-101) and 34 days for SSTs (i.e., tank 241-B-203).
International Nuclear Information System (INIS)
Hu, T.A.
2007-01-01
Assess the steady-state flammability level at normal and off-normal ventilation conditions. The methodology of flammability analysis for Hanford tank waste is developed. The hydrogen generation rate model was applied to calculate the gas generation rate for 177 tanks. Flammability concentrations and the time to reach 25% and 100% of the lower flammability limit, and the minimum ventilation rate to keep from 100 of the LFL are calculated for 177 tanks at various scenarios.
Radionuclide release calculations for SAR-08
International Nuclear Information System (INIS)
Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan
2008-04-01
Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)
Radionuclide release calculations for SAR-08
Energy Technology Data Exchange (ETDEWEB)
Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan (Enviros Consulting Ltd, Wolverhampton (United Kingdom))
2008-04-15
Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)
International Nuclear Information System (INIS)
Bass, B.R.; Bryson, J.W.
1983-02-01
Certain studies of fracture phenomena, such as pressurized-thermal-shock of cracked structures, require that crack tip parameters be determined for combined thermal and mechanical loads. A method is proposed here that modifies the isothermal formulation of deLorenzi to account for thermal strains in cracked bodies. The formulation has been implemented in the virtual-crack-extension program ORVIRT (Oak Ridge VIRTual-Crack-Extension). Program ORVIRT performs energy release rate calculations for both 2- and 3-dimensional nonlinear models of crack configurations in engineering structures. Two applications of the ORVIRT program are described. In the first, semielliptical surface cracks in an experimental test vessel are analyzed under elastic-plastic conditions using the finite element method. The second application is a thick-walled test vessel subjected to combined pressure and thermal shock loading
The rating reliability calculator
Directory of Open Access Journals (Sweden)
Solomon David J
2004-04-01
Full Text Available Abstract Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program.
Starck, Patricia L; Love, Karen; McPherson, Robert
2008-01-01
In recent years, the focus has been on increasing the number of registered nurse (RN) graduates. Numerous states have initiated programs to increase the number and quality of students entering nursing programs, and to expand the capacity of their programs to enroll additional qualified students. However, little attention has been focused on an equally, if not more, effective method for increasing the number of RNs produced-increasing the graduation rate of students enrolling. This article describes a project that undertook the task of compiling graduation data for 15 entry-level programs, standardizing terms and calculations for compiling the data, and producing a regional report on graduation rates of RN students overall and by type of program. Methodology is outlined in this article. This effort produced results that were surprising to program deans and directors and is expected to produce greater collaborative efforts to improve these rates both locally and statewide.
Calculation of tritium release from reactor's stack
International Nuclear Information System (INIS)
Akhadi, M.
1996-01-01
Method for calculation of tritium release from nuclear to environment has been discussed. Part of gas effluent contain tritium in form of HTO vapor released from reactor's stack was sampled using silica-gel. The silica-gel was put in the water to withdraw HTO vapor absorbed by silica-gel. Tritium concentration in the water was measured by liquid scintillation counter of Aloka LSC-703. Tritium concentration in the gas effluent and total release of tritium from reactor's stack during certain interval time were calculated using simple mathematic formula. This method has examined for calculation of tritium release from JRR-3M's stack of JAERI, Japan. From the calculation it was obtained the value of tritium release as much as 4.63 x 10 11 Bq during one month. (author)
Energy Technology Data Exchange (ETDEWEB)
Kelmers, A.D.; Hightower, J.R.
1987-05-01
Emplacement of contaminated reactor components involves disposal in lined and unlined auger holes in soil above the water table. The radionuclide inventory of disposed components was calculated. Information on the composition and weight of the components, as well as reasonable assumptions for the neutron flux fueling use, the time of neutron exposure, and radioactive decay after discharge, were employed in the inventory calculation. Near-field release rates of /sup 152/Eu, /sup 154/Eu, and /sup 155/Eu from control plates and cylinders were calculated for 50 years after emplacement. Release rates of the europium isotopes were uncertain. Two release-rate-limiting models were considered and a range of reasonable values were assumed for the time-to-failure of the auger-hole linear and aluminum cladding and europium solubility in SWSA-6 groundwater. The bounding europium radionuclide near-field release rates peaked at about 1.3 Ci/year total for /sup 152,154,155/Eu in 1987 for the lower bound, and at about 420 Ci/year in 1992 for the upper bound. The near-field release rates of /sup 55/Fe, /sup 59/Ni, /sup 60/Co, and /sup 63/Ni from stainless steel and cobalt alloy components, as well as of /sup 10/Be, /sup 41/Ca, and /sup 55/Fe from beryllium reflectors, were calculated for the next 100 years, assuming bulk waste corrosion was the release-rate-limiting step. Under the most conservative assumptions for the reflectors, the current (1986) total radionuclide release rate was calculated to be about 1.2 x 10/sup -4/ Ci/year, decreasing by 1992 to a steady release of about 1.5 x 10/sup -5/ Ci/year due primarily to /sup 41/Ca. 50 refs., 13 figs., 8 tabs.
Diffusion rates for elevated releases
International Nuclear Information System (INIS)
Ramsdell, J.V.
1983-11-01
A search of the literature related to diffusion from elevated sources has determined that an adequate data base exists for use in developing parameterizations for estimating diffusion rates for material released from free standing stacks at nuclear power plants. A review of published data analyses indicates that a new parameterization of horizontal diffusion rates specifically for elevated releases is not likely to significantly change the magnitudes of horizontal diffusion coefficients on the average. However, the uncertainties associated with horizontal diffusion coefficient estimates under any given set of atmospheric conditions could be reduced by a new parameterization. Similarly, a new parameterization of vertical diffusion rates would be unlikely to significantly alter the magnitudes of diffusion coefficients for unstable atmospheric conditons. However, for neutral and stable atmospheric conditions, a new parameterization of vertical diffusion rates might increase vertical diffusion coefficients significantly. The increase would move ground-level time-integrated concentration maxima closer to the plant and would increase the maxima. 55 references, 2 figures, 4 tables
H2S release rate assessment guidelines and audit forms
International Nuclear Information System (INIS)
Johnson, S.; Wilson, T.; Long, R.; Shewan, K.; Nchkalo, H.; Nelson, R.; Morand, M.
1998-01-01
Development of a process to evaluate and calculate potential hydrogen sulfide release has been recommended by the Canadian Association of Petroleum Producers' Drilling and Completion Committee, and the Alberta Energy and Utilities Board. To facilitate the process, CAPP has released guidelines describing a methodology and standard for the industry to calculate the potential hydrogen sulfide release rates of a well, and a standardized format for the documentation and retention of data. The Guidelines describe a four-step process, with each step having an increasing degree of complexity. Step One describes the zone hydrogen sulfide exclusion area maps, defining when reporting is to be used (based on well location and distance from inhabited areas). Step Two provides details of the recommended method for determining hydrogen sulfide release through a data search process. Step Three consists of a series of instructions in the use of geologic analogs, data editing and wellbore design to further refine the cumulative hydrogen sulfide release rate. Step Four contains information designed to assist in detailed geological and reservoir modeling. It is not necessary to use all four steps in all cases. The user, however, is advised to use sound engineering judgement and due diligence in the calculation decisions. Sample calculations are provided for a variety of different situations. Measurement techniques are described in an appendix. A completed example of an audit form is attached. 10 + 6 refs., tabs
ELSA: A simplified code for fission product release calculations
International Nuclear Information System (INIS)
Manenc, H.; Notley, M.J.
1996-01-01
During a light water reactor severe accident, fission products are released from the overheated core as it progressively degrades. A new computer module named ELSA is being developed to calculate fission product release. The authors approach is to model the key phenomena, as opposed to more complete mechanistic approaches. Here they present the main features of the module. Different release mechanisms have been identified and are modeled in ELSA, depending on fission product volatility: diffusion seems to govern the release of the highly volatile species if fuel oxidation is properly accounted for, whereas mass transport governs that of lower volatility fission products and fuel volatilization that of the practically involatile species
Calculations in support of a potential definition of large release
International Nuclear Information System (INIS)
Hanson, A.L.; Davis, R.E.; Mubayi, V.
1994-05-01
The Nuclear Regulatory Commission has stated a hierarchy of safety goals with the qualitative safety goals as Level I of the hierarchy, backed up by the quantitative health objectives as Level II and the large release guideline as Level III. The large release guideline has been stated in qualitative terms as a magnitude of release of the core inventory whose frequency should not exceed 10 -6 per reactor year. However, the Commission did not provide a quantitative specification of a large release. This report describes various specifications of a large release and focuses, in particular, on an examination of releases which have a potential to lead to one prompt fatality in the mean. The basic information required to set up the calculations was derived from the simplified source terms which were obtained from approximations of the NUREG-1150 source terms. Since the calculation of consequences is affected by a large number of assumptions, a generic site with a (conservatively determined) population density and meteorology was specified. At this site, various emergency responses (including no response) were assumed based on information derived from earlier studies. For each of the emergency response assumptions, a set of calculations were performed with the simplified source terms; these included adjustments to the source terms, such as the timing of the release, the core inventory, and the release fractions of different radionuclides, to arrive at a result of one mean prompt fatality in each case. Each of the source terms, so defined, has the potential to be a candidate for a large release. The calculations show that there are many possible candidate source terms for a large release depending on the characteristics which are felt to be important
Tank Z-361 dose rate calculations
International Nuclear Information System (INIS)
Richard, R.F.
1998-01-01
Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses
Fair and Reasonable Rate Calculation Data -
Department of Transportation — This dataset provides guidelines for calculating the fair and reasonable rates for U.S. flag vessels carrying preference cargoes subject to regulations contained at...
Reaction rate calculations via transmission coefficients
International Nuclear Information System (INIS)
Feit, M.D.; Alder, B.J.
1985-01-01
The transmission coefficient of a wavepacket traversing a potential barrier can be determined by steady state calculations carried out in imaginary time instead of by real time dynamical calculations. The general argument is verified for the Eckart barrier potential by a comparison of transmission coefficients calculated from real and imaginary time solutions of the Schroedinger equation. The correspondence demonstrated here allows a formulation for the reaction rate that avoids difficulties due to both rare events and explicitly time dependent calculations. 5 refs., 2 figs
Dose rate calculations for a reconnaissance vehicle
International Nuclear Information System (INIS)
Grindrod, L.; Mackey, J.; Salmon, M.; Smith, C.; Wall, S.
2005-01-01
A Chemical Nuclear Reconnaissance System (CNRS) has been developed by the British Ministry of Defence to make chemical and radiation measurements on contaminated terrain using appropriate sensors and recording equipment installed in a land rover. A research programme is under way to develop and validate a predictive capability to calculate the build-up of contamination on the vehicle, radiation detector performance and dose rates to the occupants of the vehicle. This paper describes the geometric model of the vehicle and the methodology used for calculations of detector response. Calculated dose rates obtained using the MCBEND Monte Carlo radiation transport computer code in adjoint mode are presented. These address the transient response of the detectors as the vehicle passes through a contaminated area. Calculated dose rates were found to agree with the measured data to be within the experimental uncertainties, thus giving confidence in the shielding model of the vehicle and its application to other scenarios. (authors)
International Nuclear Information System (INIS)
Cooper, P.J.; Underwood, B.Y.; Brearley, I.
1985-01-01
In the first half of the work the source-term characteristics potentially influencing behaviour were identified and examined. It was concluded that a number of source characteristics, in addition to those conventionally provided for consequence assessment, could significantly influence deposition behaviour. Linking with this, a review was undertaken of past reactor-accident risk assessment and more recent source-term studies to pick out information, if any, on the parameters of interest. The second half of the study resulted in a list of processes capable of transforming the released material vis-a-vis deposition characteristics, including processes occurring in the near field associated with the initial release transient and also those occurring over a longer time span as the plume travels downwind. Scoping calculations were performed for some of the processes in the context of idealized accident scenarios, leading to the conclusions that in some circumstances post-release mechanisms could have an important impact on the deposition behaviour of released material. Statistical theory was used to describe the behaviour of a plume both before and after detachment, and the limitations of the theory were discussed. A review of the lateral wind velocity spectra was undertaken so that simplified spectra could be constructed and used to predict the plume behaviour as a function of travel time, stability category and release duration. It was found that commonly used methods of allowing for release duration overpredicted the dependence, in general, upon release duration. For example the adoption of a stability-independent meandering term would lead to the underprediction of threshold effects such as early death and land/crop interdiction. In addition, theory indicated that the 'Y' curves for different stability categories would converge gradually with increasing travel time
Calculation method for gamma-dose rates from spherical puffs
International Nuclear Information System (INIS)
Thykier-Nielsen, S.; Deme, S.; Lang, E.
1993-05-01
The Lagrangian puff-models are widely used for calculation of the dispersion of atmospheric releases. Basic output from such models are concentrations of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on semi-infinite cloud model. This method is however only applicable for points far away from the release point. The exact calculation of the cloud dose using the volume integral requires significant computer time. The volume integral for the gamma dose could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor due to the fact that the same correction factors are used for all isotopes. The authors describe a more elaborate correction method. This method uses precalculated values of the gamma-dose rate as a function of the puff dispersion parameter (δ p ) and the distance from the puff centre for four energy groups. The release of energy for each radionuclide in each energy group has been calculated and tabulated. Based on these tables and a suitable interpolation procedure the calculation of gamma doses takes very short time and is almost independent of the number of radionuclides. (au) (7 tabs., 7 ills., 12 refs.)
Macroscopic calculational model of fission gas release from water reactor fuels
International Nuclear Information System (INIS)
Uchida, Masaki
1993-01-01
Existing models for estimating fission gas release rate usually have fuel temperature as independent variable. Use of fuel temperature, however, often brings an excess ambiguity in the estimation because it is not a rigorously definable quantity as a function of heat generation rate and burnup. To derive a mathematical model that gives gas release rate explicitly as a function of design and operational parameters, the Booth-type diffusional model was modified by changing the character of the diffusion constant from physically meaningful quantity into a mere mathematical parameter, and also changing its temperature dependency into power dependency. The derived formula was found, by proper choice of arbitrary constants, to satisfactorily predict the release rates under a variety of irradiation histories up to a burnup of 60,000 MWd/t. For simple power histories, the equation can be solved analytically by defining several transcendental functions, which enables simple calculation of release rate using graphs. (author)
Calculation method for gamma dose rates from Gaussian puffs
Energy Technology Data Exchange (ETDEWEB)
Thykier-Nielsen, S; Deme, S; Lang, E
1995-06-01
The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E{sub {gamma}}, {sigma}{sub y}, the asymmetry factor - {sigma}{sub y}/{sigma}{sub z}, the height of puff center - H and the distance from puff center R{sub xy}. To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs.
Calculation method for gamma dose rates from Gaussian puffs
International Nuclear Information System (INIS)
Thykier-Nielsen, S.; Deme, S.; Lang, E.
1995-06-01
The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E γ , σ y , the asymmetry factor - σ y /σ z , the height of puff center - H and the distance from puff center R xy . To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs
Biased Brownian dynamics for rate constant calculation.
Zou, G; Skeel, R D; Subramaniam, S
2000-01-01
An enhanced sampling method-biased Brownian dynamics-is developed for the calculation of diffusion-limited biomolecular association reaction rates with high energy or entropy barriers. Biased Brownian dynamics introduces a biasing force in addition to the electrostatic force between the reactants, and it associates a probability weight with each trajectory. A simulation loses weight when movement is along the biasing force and gains weight when movement is against the biasing force. The sampl...
The surface-forming energy release rate versus the local energy release rate
Xiao, Si; Wang, He-ling; Landis, Chad M; Hwang, Keh-Chih; Liu, Bin
2016-01-01
This paper identifies two ways to extract the energy (or power) flowing into a crack tip during propagation based on the power balance of areas enclosed by a stationary contour and a comoving contour. It is very interesting to find a contradiction that two corresponding energy release rates (ERRs), a surface-forming ERR and a local ERR, are different when stress singularity exists at a crack tip. Besides a rigorous mathematical interpretation, we deduce that the stress singularity leads to an...
Glass dissolution rate measurement and calculation revisited
Energy Technology Data Exchange (ETDEWEB)
Fournier, Maxime, E-mail: maxime.fournier@cea.fr [CEA, DEN, DTCD, SECM, F-30207, Bagnols sur Cèze (France); Ull, Aurélien; Nicoleau, Elodie [CEA, DEN, DTCD, SECM, F-30207, Bagnols sur Cèze (France); Inagaki, Yaohiro [Department of Applied Quantum Physics & Nuclear Engineering, Kyushu University, Fukuoka, 819-0395 (Japan); Odorico, Michaël [ICSM-UMR5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule, BP17171, F-30207, Bagnols sur Cèze (France); Frugier, Pierre; Gin, Stéphane [CEA, DEN, DTCD, SECM, F-30207, Bagnols sur Cèze (France)
2016-08-01
Aqueous dissolution rate measurements of nuclear glasses are a key step in the long-term behavior study of such waste forms. These rates are routinely normalized to the glass surface area in contact with solution, and experiments are very often carried out using crushed materials. Various methods have been implemented to determine the surface area of such glass powders, leading to differing values, with the notion of the reactive surface area of crushed glass remaining vague. In this study, around forty initial dissolution rate measurements were conducted following static and flow rate (SPFT, MCFT) measurement protocols at 90 °C, pH 10. The international reference glass (ISG), in the forms of powders with different particle sizes and polished monoliths, and soda-lime glass beads were examined. Although crushed glass grains clearly cannot be assimilated with spheres, it is when using the samples geometric surface (S{sub geo}) that the rates measured on powders are closest to those found for monoliths. Overestimation of the reactive surface when using the BET model (S{sub BET}) may be due to small physical features at the atomic scale—contributing to BET surface area but not to AFM surface area. Such features are very small compared with the thickness of water ingress in glass (a few hundred nanometers) and should not be considered in rate calculations. With a S{sub BET}/S{sub geo} ratio of 2.5 ± 0.2 for ISG powders, it is shown here that rates measured on powders and normalized to S{sub geo} should be divided by 1.3 and rates normalized to S{sub BET} should be multiplied by 1.9 in order to be compared with rates measured on a monolith. The use of glass beads indicates that the geometric surface gives a good estimation of glass reactive surface if sample geometry can be precisely described. Although data clearly shows the repeatability of measurements, results must be given with a high uncertainty of approximately ±25%. - Highlights: • Initial dissolution
Heat release rate of wood-plastic composites
N. M. Stark; R. H. White; C. M. Clemons
1997-01-01
Wood-plastic composites are becoming more important as a material that fulfills recycling needs. In this study, fire performance tests were conducted on several compositions of wood and plastic materials using the Ohio State University rate of heat release apparatus. Test results included five-minute average heat release rate in kW/m2 (HRR avg) and maximum heat release...
Scientific periodical publications rating's calculation and analysis
Directory of Open Access Journals (Sweden)
B. E. Nikitin
2017-01-01
Full Text Available The article considers the constructing problem of the food industry journals aggregate ratings. The streamlines of the seventeen magazines on four bibliometric indexes (SCIENCE INDEX, five-year impact factor RISC given the translated version without self-citations, h-index over 10 years and Herfindahl index, which are used in the scientific electronic library elibrary.ru was used as initial data. The statement of the problem refers to multi-criteria decision-making problems. Ranking the journals in these indexes are different from each other because bibliometric indicators account different aspects of the journals. The classical approach to thisproblems solution is based on generalized criterion building in the form of an additive convolution. However, this approach requires adherence to a number of regular conditions that may not always be performed when the practical problems solution. The reductionspossibility of the considered formulation in the form of multi-criteria decision-making tasks to the problem of collective choice. The aggregated ratings of the reporting journals are calculated by using the three social choice rules – Board procedure, Copeland procedures and Kemeny median heuristic procedures. On the basis of Spearman's rank correlation determined the quantitative evaluation of the degree of intimacy built in magazines. In particular, calculated on the basis of procedure, Board and Kemeny median aggregate ratings reporting in the logs coincided. The results showed that the constructed ordering of journals on the basis of social choice rules are in good agreement with the scientific electronic library (eLIBRARY bibliometric indicators.
Tritium transport calculations for the IFMIF Tritium Release Test Module
Energy Technology Data Exchange (ETDEWEB)
Freund, Jana, E-mail: jana.freund@kit.edu; Arbeiter, Frederik; Abou-Sena, Ali; Franza, Fabrizio; Kondo, Keitaro
2014-10-15
Highlights: • Delivery of material data for the tritium balance in the IFMIF Tritium Release Test Module. • Description of the topological models in TMAP and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). • Computation of release of tritium from the breeder solid material into the purge gas. • Computation of the loss of tritium over the capsule wall, rig hull, container wall and purge gas return line. - Abstract: The IFMIF Tritium Release Test Module (TRTM) is projected to measure online the tritium release from breeder ceramics and beryllium pebble beds under high energy neutron irradiation. Tritium produced in the pebble bed of TRTM is swept out continuously by a purge gas flow, but can also permeate into the module's metal structures, and can be lost by permeation to the environment. According analyses on the tritium inventory are performed to support IFMIF plant safety studies, and to support the experiment planning. This paper describes the necessary elements for calculation of the tritium transport in the Tritium Release Test Module as follows: (i) applied equations for the tritium balance, (ii) material data from literature and (iii) the topological models and the computation of the five different cases; namely release of tritium from the breeder solid material into the purge gas, loss of tritium over the capsule wall, rig hull, container wall and purge gas return line in detail. The problem of tritium transport in the TRTM has been studied and analyzed by the Tritium Migration Analysis Program (TMAP) and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). TMAP has been developed at INEEL and now exists in Version 7. FUS-TPC Code was written in MATLAB with the original purpose to study the tritium transport in Helium Cooled Lead Lithium (HCLL) blanket and in a later version the Helium Cooled Pebble Bed (HCPB) blanket by [6] (Franza, 2012). This code has been further modified to be applicable to the TRTM. Results from the
Tritium transport calculations for the IFMIF Tritium Release Test Module
International Nuclear Information System (INIS)
Freund, Jana; Arbeiter, Frederik; Abou-Sena, Ali; Franza, Fabrizio; Kondo, Keitaro
2014-01-01
Highlights: • Delivery of material data for the tritium balance in the IFMIF Tritium Release Test Module. • Description of the topological models in TMAP and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). • Computation of release of tritium from the breeder solid material into the purge gas. • Computation of the loss of tritium over the capsule wall, rig hull, container wall and purge gas return line. - Abstract: The IFMIF Tritium Release Test Module (TRTM) is projected to measure online the tritium release from breeder ceramics and beryllium pebble beds under high energy neutron irradiation. Tritium produced in the pebble bed of TRTM is swept out continuously by a purge gas flow, but can also permeate into the module's metal structures, and can be lost by permeation to the environment. According analyses on the tritium inventory are performed to support IFMIF plant safety studies, and to support the experiment planning. This paper describes the necessary elements for calculation of the tritium transport in the Tritium Release Test Module as follows: (i) applied equations for the tritium balance, (ii) material data from literature and (iii) the topological models and the computation of the five different cases; namely release of tritium from the breeder solid material into the purge gas, loss of tritium over the capsule wall, rig hull, container wall and purge gas return line in detail. The problem of tritium transport in the TRTM has been studied and analyzed by the Tritium Migration Analysis Program (TMAP) and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). TMAP has been developed at INEEL and now exists in Version 7. FUS-TPC Code was written in MATLAB with the original purpose to study the tritium transport in Helium Cooled Lead Lithium (HCLL) blanket and in a later version the Helium Cooled Pebble Bed (HCPB) blanket by [6] (Franza, 2012). This code has been further modified to be applicable to the TRTM. Results from the
Calculation of the Fission Product Release for the HTR-10 based on its Operation History
International Nuclear Information System (INIS)
Xhonneux, A.; Druska, C.; Struth, S.; Allelein, H.-J.
2014-01-01
Since the first criticality of the HTR-10 test reactor in 2000, a rather complex operation history was performed. As the HTR-10 is the only pebble bed reactor in operation today delivering experimental data for HTR simulation codes, an attempt was made to simulate the whole reactor operation up to the presence. Special emphasis was put on the fission product release behaviour as it is an important safety aspect of such a reactor. The operation history has to be simulated with respect to the neutronics, fluid mechanics and depletion to get a detailed knowledge about the time-dependent nuclide inventory. In this paper we report about such a simulation with VSOP 99/11 and our new fission product release code STACY. While STACY (Source Term Analysis Code System) so far was able to calculate the fission product release rates in case of an equilibrium core and during transients, it now can also be applied to running-in-phases. This coupling demonstrates a first step towards an HCP Prototype. Based on the published power histogram of the HTR-10 and additional information about the fuel loading and shuffling, a coupled neutronics, fluid dynamics and depletion calculation was performed. Special emphasis was put on the complex fuel-shuffling scheme within both VSOP and STACY. The simulations have shown that the HTR-10 up to now generated about 2580 MWd while reshuffling the core about 2.3 times. Within this paper, STACY results for the equilibrium core will be compared with FRESCO-II results being published by INET. Compared to these release rates, which are based on a few user defined life histories, in this new approach the fission product release rates of Ag-110m, Cs-137, Sr-90 and I-131 have been simulated for about 4000 tracer pebbles with STACY. For the calculation of the HTR-10 operation history time-dependent release rates are being presented as well. (author)
Benchmark calculations for evaluation methods of gas volumetric leakage rate
International Nuclear Information System (INIS)
Asano, R.; Aritomi, M.; Matsuzaki, M.
1998-01-01
A containment function of radioactive materials transport casks is essential for safe transportation to prevent the radioactive materials from being released into environment. Regulations such as IAEA standard determined the limit of radioactivity to be released. Since is not practical for the leakage tests to measure directly the radioactivity release from a package, as gas volumetric leakages rates are proposed in ANSI N14.5 and ISO standards. In our previous works, gas volumetric leakage rates for several kinds of gas from various leaks were measured and two evaluation methods, 'a simple evaluation method' and 'a strict evaluation method', were proposed based on the results. The simple evaluation method considers the friction loss of laminar flow with expansion effect. The strict evaluating method considers an exit loss in addition to the friction loss. In this study, four worked examples were completed for on assumed large spent fuel transport cask (Type B Package) with wet or dry capacity and at three transport conditions; normal transport with intact fuels or failed fuels, and an accident in transport. The standard leakage rates and criteria for two kinds of leak test were calculated for each example by each evaluation method. The following observations are made based upon the calculations and evaluations: the choked flow model of ANSI method greatly overestimates the criteria for tests ; the laminar flow models of both ANSI and ISO methods slightly overestimate the criteria for tests; the above two results are within the design margin for ordinary transport condition and all methods are useful for the evaluation; for severe condition such as failed fuel transportation, it should pay attention to apply a choked flow model of ANSI method. (authors)
Release rates from waste packages in a salt repository
International Nuclear Information System (INIS)
Chambre, P.L.; Hwang, Y.; Lee, W.W.L.; Pigford, T.H.
1987-06-01
In this report we present estimates of radionuclide release rates from waste packages into salt. This conservative and bounding analysis shows that release rates from waste packages in salt are well below the US Nuclear Regulatory Commission's performance objectives for the engineered barrier system. 2 refs., 2 figs
Radionuclide release calculations for selected severe accident scenarios
International Nuclear Information System (INIS)
Denning, R.S.; Leonard, M.T.; Cybulskis, P.; Lee, K.W.; Kelly, R.F.; Jordan, H.; Schumacher, P.M.; Curtis, L.A.
1990-08-01
This report provides the results of source term calculations that were performed in support of the NUREG-1150 study. ''Severe Accident Risks: An Assessment for Five US Nuclear Power Plants.'' This is the sixth volume of a series of reports. It supplements results presented in the earlier volumes. Analyses were performed for three of the NUREG-1150 plants: Peach Bottom, a Mark I, boiling water reactor; Surry, a subatmospheric containment, pressurized water reactor; and Sequoyah, an ice condenser containment, pressurized water reactor. Complete source term results are presented for the following sequences: short term station blackout with failure of the ADS system in the Peach Bottom plant; station blackout with a pump seal LOCA for the Surry plant; station blackout with a pump seal LOCA in the Sequoyah plant; and a very small break with loss of ECC and spray recirculation in the Sequoyah plant. In addition, some partial analyses were performed which did not require running all of the modules of the Source Term Code Package. A series of MARCH3 analyses were performed for the Surry and Sequoyah plants to evaluate the effects of alternative emergency operating procedures involving primary and secondary depressurization on the progress of the accident. Only thermal-hydraulic results are provided for these analyses. In addition, three accident sequences were analyzed for the Surry plant for accident-induced failure of steam generator tubes. In these analyses, only the transport of radionuclides within the primary system and failed steam generator were examined. The release of radionuclides to the environment is presented for the phase of the accident preceding vessel meltthrough. 17 refs., 176 figs., 113 tabs
Database crime to crime match rate calculation.
Buckleton, John; Bright, Jo-Anne; Walsh, Simon J
2009-06-01
Guidance exists on how to count matches between samples in a crime sample database but we are unable to locate a definition of how to estimate a match rate. We propose a method that does not proceed from the match counting definition but which has a strong logic.
Controlling Object Heat Release Rate using Geometrical Features
Kraft, Stefan Marc
2017-01-01
An experimental study was conducted to determine the effect of complex geometries on the burning rate of materials made using additive manufacturing. Controlling heat release rate has applicability in limiting fire hazards as well as for designing fuels for optimal burning rate. The burning rate of a structure is a function of the material properties as well as the airflow through it, which is dictated by the geometry. This burning rate is generally proportional to the porosity for obj...
Reexamining the Dissolution of Spent Fuel: A Comparison of Different Methods for Calculating Rates
International Nuclear Information System (INIS)
Hanson, Brady D.; Stout, Ray B.
2004-01-01
Dissolution rates for spent fuel have typically been reported in terms of a rate normalized to the surface area of the specimen. Recent evidence has shown that neither the geometric surface area nor that measured with BET accurately predicts the effective surface area of spent fuel. Dissolution rates calculated from results obtained by flowthrough tests were reexamined comparing the cumulative releases and surface area normalized rates. While initial surface area is important for comparison of different rates, it appears that normalizing to the surface area introduces unnecessary uncertainty compared to using cumulative or fractional release rates. Discrepancies in past data analyses are mitigated using this alternative method
49 CFR 1141.1 - Procedures to calculate interest rates.
2010-10-01
... the portion of the year covered by the interest rate. A simple multiplication of the nominal rate by... 49 Transportation 8 2010-10-01 2010-10-01 false Procedures to calculate interest rates. 1141.1... TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE PROCEDURES TO CALCULATE INTEREST RATES...
Chudnovsky, A.; Gommerstadt, B.
1985-01-01
A number of papers have been presented on the evaluation of energy release rate for thermoelasticity and corresponding J integral. Two main approaches were developed to treat energy release rate in elasticity. The first is based on direct calculation of the potential energy rate with respect to crack length. The second makes use of Lagrangian formalism. The translational and expansional energy release rates in thermoelasticity are studied by employing the formalism of irreversible thermodynamics and the Crack Layer Approach.
Calculating the Rate of Senescence From Mortality Data
DEFF Research Database (Denmark)
Koopman, Jacob J E; Rozing, Maarten P; Kramer, Anneke
2016-01-01
, they do not fit mortality rates at young and old ages. Therefore, we developed a method to calculate senescence rates from the acceleration of mortality directly without modeling the mortality rates. We applied the different methods to age group-specific mortality data from the European Renal Association......, the rate of senescence can be calculated directly from non-modeled mortality rates, overcoming the disadvantages of an indirect estimation based on modeled mortality rates....
The burning and smoke release rates of sodium pool fires
International Nuclear Information System (INIS)
Newman, R.N.; Payne, J.F.B.
1976-10-01
The burning rates and smoke release fractions of sodium pool fires have been measured over the pool temperature range 250 0 C to 750 0 C. A theoretical model is derived which satisfactorily predicts the burning rate over the above temperature range. The theory further predicts that the burning rate should be independent of pool diameter, a prediction supported by a comparison of burning rate data from this study and available data from other studies. (author)
In situ release rates of Cu and Zn from commercial antifouling paints at different salinities.
Lagerström, Maria; Lindgren, J Fredrik; Holmqvist, Albin; Dahlström, Mia; Ytreberg, Erik
2018-02-01
Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
Release rates of soluble species at Yucca Mountain
International Nuclear Information System (INIS)
Lee, W.W.-L.; Pigford, T.H.
1989-02-01
Experimental leaching of spent fuel shows that some fission product species are preferentially released upon contact with water. We analyze the conservative case of bare spent fuel in contact with saturated tuff using diffusional mass transfer analysis. For the parameter values used, the USNRC release rate limit is not exceeded, except for 99 Tc. The presence of a container and the distribution of water contact over time will assist in meeting this criterion. 6 figs., 2 tabs
Assessing the reliability of calculated catalytic ammonia synthesis rates
DEFF Research Database (Denmark)
Medford, Andrew James; Wellendorff, Jess; Vojvodic, Aleksandra
2014-01-01
We introduce a general method for estimating the uncertainty in calculated materials properties based on density functional theory calculations. We illustrate the approach for a calculation of the catalytic rate of ammonia synthesis over a range of transition-metal catalysts. The correlation...... between errors in density functional theory calculations is shown to play an important role in reducing the predicted error on calculated rates. Uncertainties depend strongly on reaction conditions and catalyst material, and the relative rates between different catalysts are considerably better described...
Fracture patterns and the energy release rate of phosphorene.
Liu, Ning; Hong, Jiawang; Pidaparti, Ramana; Wang, Xianqiao
2016-03-14
Phosphorene, also known as monolayer black phosphorus, has been enjoying popularity in electronic devices due to its superior electrical properties. However, it's relatively low Young's modulus, low fracture strength and susceptibility to structural failure have limited its application in mechanical devices. Therefore, in order to design more mechanically reliable devices that utilize phosphorene, it is necessary to explore the fracture patterns and energy release rate of phosphorene. In this study, molecular dynamics simulations are performed to investigate phosphorene's fracture mechanism. The results indicate that fracture under uniaxial tension along the armchair direction is attributed to a break in the interlayer bond angles, while failure in the zigzag direction is triggered by the break in both intra-layer angles and bonds. Furthermore, we developed a modified Griffith criterion to analyze the energy release rate of phosphorene and its dependence on the strain rates and orientations of cracks. Simulation results indicate that phosphorene's energy release rate remains almost unchanged in the armchair direction while it fluctuates intensively in the zigzag direction. Additionally, the strain rate was found to play a negligible role in the energy release rate. The geometrical factor α in the Griffith's criterion is almost constant when the crack orientation is smaller than 45 degree, regardless of the crack orientation and loading direction. Overall, these findings provide helpful insights into the mechanical properties and failure behavior of phosphorene.
Release rate of diazinon from microcapsule based on melamine formaldehyde
Noviana Utami C., S.; Rochmadi
2018-04-01
The microcapsule containing diazinon as the core material and melamine formaldehyde as the membrane material have been synthesized by in situ polymerization method. The microcapsule membrane in this research is melamine formaldehyde (MF). This research aims to study the effect of pH and temperature on the release rate of diazinon from microcapsule based on melamine formaldehyde in aqueous medium. The results showed that pH and temperature has little effect on the release rate of diazinon from microcapsule based on melamine formaldehyde. This is due to the diffusion through the microcapsule membrane is not influenced by the pH and temperature of the solution outside of microcapsule.
Heat release rate from the combustion of uranium
International Nuclear Information System (INIS)
Solbrig, C.W.
1995-01-01
Fuel treatment is planned at the Argonne National Laboratory on EBR-II spent fuel. The electrochemical treatment process is carried out in a cell with an argon atmosphere to prevent any reaction. The amount of fuel processed at any time is limited by the amount of energy which could be released by metal combustion if air is inadvertently allowed into the cell since the heat release would increase the cell pressure. The cell pressure is required to be below atmospheric even if combustion occurs to ensure no cell gas/aerosol is released to the environment. Metal fires can release large amounts of heat. In certain configurations such as fine particulate, metal can be pyrophoric at room temperature. When the metal is a nuclear fuel, it is important to be able to predict the reaction/heat release rate if the metal is inadvertently exposed to air. A realistic combustion model is needed to predict heat release rates for the many different flow and transport configurations which exist in the various fuel processing steps. A model for the combustion of uranium is developed here which compares satisfactorily to experimental data
Measurement and calculation of radon releases from uranium mill tailings
International Nuclear Information System (INIS)
1992-01-01
The mining and milling of uranium ores produces large quantities of radioactive wastes. Although relatively small in magnitude compared to tailings from metal mining and extraction processes, the present worldwide production of such tailings exceeds 20 million tonnes annually. There is thus a need to ensure that the environmental and health risks from these materials are reduced to an acceptable level. This report has been written as a complement to another publication entitled Current Practices for the Management and Confinement of Uranium Mill Tailings, IAEA Technical Reports Series No. 335, which provides a general overview of all the important factors in the siting, design and construction of tailings impoundments, and in the overall management of tailings with due consideration give to questions of the release of pollutants from tailings piles. The present report provides a comprehensive overview of the release, control and monitoring of radon, including computational methods. The report was first drafted in 1989 and was then reviewed at an Advisory Group meeting in 1990. 42 refs, 9 figs, 3 tabs
Discussion on the methods for calculation release limits for low-level radioactive waste
International Nuclear Information System (INIS)
Cao Fengbo; Liu Xiaochao
2012-01-01
The release request for low-level radioactive waste are briefly described in this paper. Associating with the conditions of low-level radioactive waste of some radioactive waste processing station, the methods and gist for calculating release limits for low-level radioactive waste with national release limits and annual effective dose limit for the public or the occupation are discussed. Then release limits for the low-level radioactive waste are also proposed. (authors)
Updates to In-Line Calculation of Photolysis Rates
How photolysis rates are calculated affects ozone and aerosol concentrations predicted by the CMAQ model and the model?s run-time. The standard configuration of CMAQ uses the inline option that calculates photolysis rates by solving the radiative transfer equation for the needed ...
SECURE-400 MW: Failure analysis and calculation of release
International Nuclear Information System (INIS)
Bento, J.-P.
1978-11-01
The environmental effects of SECURE-400 MW has been investigated for normal operation and after an accident. When calculating the doses during normal operation it has been assumed that 0.1 % of the fuel elements in the core have fuel cladding damages. The doses after an accident have been calculated only for the cases when there might be an effect on the environment: accidents at change of fuel, fracture of the biggest gas pipe and fracture of the main coolant loop. The result of the investigation is that a core melting accident in SECURE 400 is impossible due to the design of the different systems. Other typs of accidents which might happen will give extremly low doses to the environment. The doses will not differ significantly from doses during normal operation. (K.K.)
International Nuclear Information System (INIS)
Strenge, D.L.; Watson, E.C.; Houston, J.R.
1975-06-01
A computer program, SUBDOSA, was developed for calculating external γ and β doses to individuals from the accidental release of radionuclides to the atmosphere. Characteristics of SUBDOSA are: doses from both γ and β radiation are calculated as a function of depth in tissue, summed and reported as skin, eye, gonadal, and total body dose; doses are calculated for releases within each of several release time intervals and nuclide inventories and atmospheric dispersion conditions are considered for each time interval; radioactive decay is considered during the release and/or transit using a chain decay scheme with branching to account for transitions to and from isomeric states; the dose from gamma radiation is calculated using a numerical integration technique to account for the finite size of the plume; and the program computes and lists the normalized air concentrations at ground level as a function of distance from the point of release. (auth)
Zhao, Qingying; Li, Min; Luo, Jun
2017-12-04
In nanomachine applications towards targeted drug delivery, drug molecules released by nanomachines propagate and chemically react with tumor cells in aqueous environment. If the nanomachines release drug molecules faster than the tumor cells react, it will result in loss and waste of drug molecules. It is a potential issue associated with the relationship among reaction rate, release rate and efficiency. This paper aims to investigate the relationship among reaction rate, release rate and efficiency based on two drug reception models. We expect to pave a way for designing a control method of drug release. We adopted two analytical methods that one is drug reception process based on collision with tumors and another is based on Michaelis Menten enzymatic kinetics. To evaluate the analytical formulations, we used the well-known simulation framework N3Sim to establish simulations. The analytical results of the relationship among reaction rate, release rate and efficiency is obtained, which match well with the numerical simulation results in a 3-D environment. Based upon two drug reception models, the results of this paper would be beneficial for designing a control method of nanomahine-based drug release.
Calculation of the ingestion critical dose rate for the Goiania radioactive waste repository
International Nuclear Information System (INIS)
Passos, E.M. dos; Martin Alves, A.S. De
1994-01-01
The calculation results of the critical distance for the ingestion dose rate due to a hypothetical Cs-137 release from the Abadia de Goias repository are shown. The work is based on the pathway repository-aquifer-well food chain. The calculations were based upon analytical models for the migration of radioisotopes through the aquifer and for its transfer from well water to food. (author)
Electron transfer rates and energy releases during denitrification of municipal wastewater
DEFF Research Database (Denmark)
Abdul-Talib, S.; Ujang, Z; Vollertsen, J.
2004-01-01
could be simplified by a two-stage process. In the first stage, nitrate was utilised with significant accumulation of nitrite. In the second stage nitrite was utilised when nitrate depleted. Denitrification rates during the two stages were expressed in terms of electron equivalents (e-eq.) in order...... to compare the process when differennt electron acceptors namlely, nitrate and nitrite were utilised. The energy release rates during the two stages were calculated and compared....
Dose Rate Calculations for Rotary Mode Core Sampling Exhauster
Foust, D J
2000-01-01
This document provides the calculated estimated dose rates for three external locations on the Rotary Mode Core Sampling (RMCS) exhauster HEPA filter housing, per the request of Characterization Field Engineering.
Dose Rate Calculations for Rotary Mode Core Sampling Exhauster
International Nuclear Information System (INIS)
FOUST, D.J.
2000-01-01
This document provides the calculated estimated dose rates for three external locations on the Rotary Mode Core Sampling (RMCS) exhauster HEPA filter housing, per the request of Characterization Field Engineering
Calculating stocking rates for game ranches: substitution ratios for ...
African Journals Online (AJOL)
Calculating stocking rates for game ranches: substitution ratios for use in the Mopani ... Reports on a study conducted to quantify the overlap in ungulate resource-use on a game ranch, and to demonstrate how ... AJOL African Journals Online.
Effect of crack-microcracks interaction on energy release rates
Chudnovsky, A.; Wu, Shaofu
1990-01-01
The energy release rates associated with the main crack advancing into its surrounding damage zone, and the damage zone translation relative to the main crack, as well as the energy of interaction between the crack and the damage zone are analyzed. The displacement and stress fields for this crack-damage interaction problem are reconstructed by employing a semi-empirical stress analysis which involves experimental evaluation of the average microcrack density in the damage zone.
Radionuclide release rates from spent fuel for performance assessment modeling
International Nuclear Information System (INIS)
Curtis, D.B.
1994-01-01
In a scenario of aqueous transport from a high-level radioactive waste repository, the concentration of radionuclides in water in contact with the waste constitutes the source term for transport models, and as such represents a fundamental component of all performance assessment models. Many laboratory experiments have been done to characterize release rates and understand processes influencing radionuclide release rates from irradiated nuclear fuel. Natural analogues of these waste forms have been studied to obtain information regarding the long-term stability of potential waste forms in complex natural systems. This information from diverse sources must be brought together to develop and defend methods used to define source terms for performance assessment models. In this manuscript examples of measures of radionuclide release rates from spent nuclear fuel or analogues of nuclear fuel are presented. Each example represents a very different approach to obtaining a numerical measure and each has its limitations. There is no way to obtain an unambiguous measure of this or any parameter used in performance assessment codes for evaluating the effects of processes operative over many millennia. The examples are intended to suggest by example that in the absence of the ability to evaluate accuracy and precision, consistency of a broadly based set of data can be used as circumstantial evidence to defend the choice of parameters used in performance assessments
Factors affecting calculations of dose resulting from a tritium release into the atmosphere
International Nuclear Information System (INIS)
Otaduy, P.; Easterly, C.E.; Booth, R.S.; Jacobs, D.G.
1976-01-01
Tritium releases in the form of HT represent a lower hazard to man than releases as HTO. However, during movement in the environment, HT is converted into HTO. The effects of the conversion rate on calcultions of dose are described, and a general method is presented for determining the dose from tritium for various conversion rates and relative HTO/HT risk factors
Experiences with leak rate calculations methods for LBB application
International Nuclear Information System (INIS)
Grebner, H.; Kastner, W.; Hoefler, A.; Maussner, G.
1997-01-01
In this paper, three leak rate computer programs for the application of leak before break analysis are described and compared. The programs are compared to each other and to results of an HDR Reactor experiment and two real crack cases. The programs analyzed are PIPELEAK, FLORA, and PICEP. Generally, the different leak rate models are in agreement. To obtain reasonable agreement between measured and calculated leak rates, it was necessary to also use data from detailed crack investigations
Experiences with leak rate calculations methods for LBB application
Energy Technology Data Exchange (ETDEWEB)
Grebner, H.; Kastner, W.; Hoefler, A.; Maussner, G. [and others
1997-04-01
In this paper, three leak rate computer programs for the application of leak before break analysis are described and compared. The programs are compared to each other and to results of an HDR Reactor experiment and two real crack cases. The programs analyzed are PIPELEAK, FLORA, and PICEP. Generally, the different leak rate models are in agreement. To obtain reasonable agreement between measured and calculated leak rates, it was necessary to also use data from detailed crack investigations.
Radioisotopic composition of yellowcake: an estimation of stack release rates
International Nuclear Information System (INIS)
Momeni, M.H.; Kisieleski, W.E.; Rayno, D.R.; Sabau, C.S.
1979-12-01
Uranium concentrate (yellowcake) composites from four mills (Anaconda, Kerr-McGee, Highland, and Uravan) were analyzed for U-238, U-235, U-234, Th-230, Ra-226, and Pb-210. The ratio of specific activities of U-238 to U-234 in the composites suggested that secular radioactive equilibrium exists in the ore. The average activity ratios in the yellowcake were determined to be 2.7 x 10 -3 (Th-230/U-238), 5 x 10 -4 (Ra-226/U-238) and 2 x 10 -4 (Pb-210/U-238). Based on earlier EPA measurements of the release rates from the stacks, the amount of yellowcake released was determined to be 0.1% of the amount processed
International Nuclear Information System (INIS)
Raskob, W.; Hasemann, I.
1992-08-01
This report documents conditions, data and results of dose calculations for accidental and normal operation releases of tritium and activation products, performed within the NET subtask SEP2.2 ('NET-Benchmark') of the European Fusion Technology Programme. For accidental releases, the computer codes UFOTRI and COSYMA for assessing the radiological consequences, have been applied for both deterministic and probabilistic calculations. The influence on dose estimates of different release times (2 minutes / 1 hour), two release heights (10 m / 150 m), two chemical forms of tritium (HT/HTO), and two different model approaches for the deposition velocity of HTO on soil was investigated. The dose calculations for normal operation effluents were performed using the tritium model of the German regulatory guidelines, parts of the advanced dose assessment model NORMTRI still under development, and the statistical atmospheric dispersion model ISOLA. Accidental and normal operation source terms were defined as follows: 10g (3.7 10 15 Bq) for accidental tritium releases, 10 Ci/day (3.7 10 11 Bq/day) for tritium releases during normal operation and unit releases of 10 9 Bq for accidental releases of activation products and fission products. (orig./HP) [de
International Nuclear Information System (INIS)
Hotson, J.; Stacey, A.; Nair, S.
1980-07-01
The basic methodology incorporated in the POPFOOD computer code is described, which may be used to calculate equilibrium collective dose rates associated with continuous atmospheric releases and arising from consumption of a broad range of food products. The standard data libraries associated with the code are also described. These include a data library, based on the 1972 agricultural census, describing the spatial distribution of production, in England, Wales and Scotland, of the following food products: milk; beef and veal; pork bacon and ham; poultrymeat; eggs; mutton and lamb; root vegetables; green vegetables; fruit; cereals. Illustrative collective dose calculations were made for the case of 1 Ci per year emissions of 131 I, tritium and 14 C from a typical rural UK site. The calculations indicate that the ingestion pathway results in a greater collective dose than that via inhalation, with the contributions from consumption of root and green vegetables, and cereals being of comparable significance to that from liquid milk consumption, in all three cases. (author)
Model for calculating shock loading and release paths for multicomponent geologic media
International Nuclear Information System (INIS)
Butkovich, T.R.; Moran, B.; Burton, D.E.
1981-07-01
A model has been devised to calculate shock Hugoniots and release paths off the Hugoniots for multicomponent rocks containing silicate, carbonate, and water. Hugoniot equations of state are constructed from relatively simple measurements of rock properties including bulk density, grain density of the silicate component, and weight fractions of water and carbonate. Release paths off the composite Hugoniot are calculated by mixing release paths off the component Hugoniots according to their weight fractions. If the shock imparts sufficient energy to the component to cause vaporization, a gas equation of state is used to calculate the release paths. For less energetic shocks, the rock component will unload like a solid or liquid, taking into account the irreversible removal of air-filled porosity
APUAMA: a software tool for reaction rate calculations.
Euclides, Henrique O; P Barreto, Patricia R
2017-06-01
APUAMA is a free software designed to determine the reaction rate and thermodynamic properties of chemical species of a reagent system. With data from electronic structure calculations, the APUAMA determine the rate constant with tunneling correction, such as Wigner, Eckart and small curvature, and also, include the rovibrational level of diatomic molecules. The results are presented in the form of Arrhenius-Kooij form, for the reaction rate, and the thermodynamic properties are written down in the polynomial form. The word APUAMA means "fast" in Tupi-Guarani Brazilian language, then the code calculates the reaction rate on a simple and intuitive graphic interface, the form fast and practical. As program output, there are several ASCII files with tabulated information for rate constant, rovibrational levels, energy barriers and enthalpy of reaction, Arrhenius-Kooij coefficient, and also, the option to the User save all graphics in BMP format.
Benchmark calculations of thermal reaction rates. I - Quantal scattering theory
Chatfield, David C.; Truhlar, Donald G.; Schwenke, David W.
1991-01-01
The thermal rate coefficient for the prototype reaction H + H2 yields H2 + H with zero total angular momentum is calculated by summing, averaging, and numerically integrating state-to-state reaction probabilities calculated by time-independent quantum-mechanical scattering theory. The results are very carefully converged with respect to all numerical parameters in order to provide high-precision benchmark results for confirming the accuracy of new methods and testing their efficiency.
Dynamic energy release rate in couple-stress elasticity
International Nuclear Information System (INIS)
Morini, L; Piccolroaz, A; Mishuris, G
2013-01-01
This paper is concerned with energy release rate for dynamic steady state crack problems in elastic materials with microstructures. A Mode III semi-infinite crack subject to loading applied on the crack surfaces is considered. The micropolar behaviour of the material is described by the theory of couple-stress elasticity developed by Koiter. A general expression for the dynamic J-integral including both traslational and micro-rotational inertial contributions is derived, and the conservation of this integral on a path surrounding the crack tip is demonstrated
Efficient calculation of atomic rate coefficients in dense plasmas
Aslanyan, Valentin; Tallents, Greg J.
2017-03-01
Modelling electron statistics in a cold, dense plasma by the Fermi-Dirac distribution leads to complications in the calculations of atomic rate coefficients. The Pauli exclusion principle slows down the rate of collisions as electrons must find unoccupied quantum states and adds a further computational cost. Methods to calculate these coefficients by direct numerical integration with a high degree of parallelism are presented. This degree of optimization allows the effects of degeneracy to be incorporated into a time-dependent collisional-radiative model. Example results from such a model are presented.
Calculation of gamma ray exposure rates from uranium ore bodies
International Nuclear Information System (INIS)
Thomson, J.E.; Wilson, O.J.
1980-02-01
The planning of operations associated with uranium mines often requires that estimates be made of the exposure rates from various ore bodies. A straight-forward method of calculating the exposure rate from an arbitrarily shaped body is presented. Parameters for the calculation are evaluated under the assumption of secular equilibrium of uranium with its daughters and that the uranium is uniformly distributed throughout an average soil mixture. The spectral distribution of the emitted gamma rays and the effect of air attenuation are discussed. Worked examples are given of typical situations encountered in uranium mines
Use of OND-86 recommendations for calculation of the Shelter radioactive release
International Nuclear Information System (INIS)
Bogatov, S.A.
2000-01-01
A model of radioactive release from the Shelter has been considered under current operation conditions. Integral assessment of current dust release has been done on the base of natural ventilation rate. Model predictions are consistent (20% accuracy) with experimental results of air contamination measurements at the earth surface. 12 refs., 1 tab., 6 figs
Impact ionisation rate calculations in wide band gap semiconductors
International Nuclear Information System (INIS)
Harrison, D.
1998-09-01
Calculations of band-to-band impact ionisation rates performed in the semi-classical Fermi's Golden Rule approximation are presented here for the semiconductors GaAs, In 0.53 Ga 0.47 As and Si 0.5 Ge 0.5 at 300K. The crystal band structure is calculated using the empirical pseudopotential method. To increase the speed with which band structure data at arbitrary k-vectors can be obtained, an interpolation scheme has been developed. Energies are quadratically interpolated on adapted meshes designed to ensure accuracy is uniform throughout the Brillouin zone, and pseudowavefunctions are quadratically interpolated on a regular mesh. Matrix elements are calculated from the pseudowavefunctions, and include the terms commonly neglected in calculations for narrow band gap materials and an isotropic approximation to the full wavevector and frequency dependent dielectric function. The numerical integration of the rate over all distinct energy and wavevector conserving transitions is performed using two different algorithms. Results from each are compared and found to be in good agreement, indicating that the algorithms are reliable. The rates for electrons and holes in each material are calculated as functions of the k-vector of the impacting carriers, and found to be highly anisotropic. Average rates for impacting carriers at a given energy are calculated and fitted to Keldysh-type expressions with higher than quadratic dependence of the rate on energy above threshold being obtained in all cases. The average rates calculated here are compared to results obtained by other workers, with reasonable agreement being obtained for GaAs, and poorer agreement obtained for InGaAs and SiGe. Possible reasons for the disagreement are investigated. The impact ionisation thresholds are examined and k-space and energy distributions of generated carriers are determined. The role of threshold anisotropy, variation in the matrix elements and the shape of the bands in determining
Comodulation masking release in bit-rate reduction systems
DEFF Research Database (Denmark)
Vestergaard, Martin David; Rasmussen, Karsten Bo; Poulsen, Torben
1999-01-01
It has been suggested that the level dependence of the upper masking slope be utilized in perceptual models in bit-rate reduction systems. However, comodulation masking release (CMR) phenomena lead to a reduction of the masking effect when a masker and a probe signal are amplitude modulated...... with the same frequency. In bit-rate reduction systems the masker would be the audio signal and the probe signal would represent the quantization noise. Masking curves have been determined for sinusoids and 1-Bark-wide noise maskers in order to investigate the risk of CMR, when quantizing depths are fixed...... in accordance with psycho-acoustical principles. Masker frequencies of 500 Hz, 1 kHz, and 2 kHz have been investigated, and the masking of pure tone probes has been determined in the first four 1/3 octaves above the masker. Modulation frequencies between 6 and 20 Hz were used with a modulation depth of 0...
Variable temperature effects on release rates of readily soluble nuclides
International Nuclear Information System (INIS)
Kim, C.-L.; Light, W.B.; Lee, W.W.-L.; Chambre, P.L.; Pigford, T.H.
1988-09-01
In this paper we study the effect of temperature on the release rate of readily soluble nuclides, as affected by a time-temperature dependent diffusion coefficient. In this analysis ground water fills the voids in the waste package at t = 0 and one percent of the inventories of cesium and iodine are immediately dissolved into the void water. Mass transfer resistance of partly failed container and cladding is conservatively neglected. The nuclides move through the void space into the surrounding rock under a concentration gradient. We use an analytic solution to compute the nuclide concentration in the gap or void, and the mass flux rate into the porous rock. 8 refs., 4 figs
The calculation of dose rates from rectangular sources
International Nuclear Information System (INIS)
Hartley, B.M.
1998-01-01
A common problem in radiation protection is the calculation of dose rates from extended sources and irregular shapes. Dose rates are proportional to the solid angle subtended by the source at the point of measurement. Simple methods of calculating solid angles would assist in estimating dose rates from large area sources and therefore improve predictive dose estimates when planning work near such sources. The estimation of dose rates is of particular interest to producers of radioactive ores but other users of bulk radioactive materials may have similar interest. The use of spherical trigonometry can assist in determination of solid angles and a simple equation is derived here for the determination of the dose at any distance from a rectangular surface. The solid angle subtended by complex shapes can be determined by modelling the area as a patchwork of rectangular areas and summing the solid angles from each rectangle. The dose rates from bags of thorium bearing ores is of particular interest in Western Australia and measured dose rates from bags and containers of monazite are compared with theoretical estimates based on calculations of solid angle. The agreement is fair but more detailed measurements would be needed to confirm the agreement with theory. (author)
Radionuclide release rate inversion of nuclear accidents in nuclear facility based on Kalman filter
International Nuclear Information System (INIS)
Tang Xiuhuan; Bao Lihong; Li Hua; Wan Junsheng
2014-01-01
The rapidly and continually back-calculating source term is important for nuclear emergency response. The Gaussian multi-puff atmospheric dispersion model was used to produce regional environment monitoring data virtually, and then a Kalman filter was designed to inverse radionuclide release rate of nuclear accidents in nuclear facility and the release rate tracking in real time was achieved. The results show that the Kalman filter combined with Gaussian multi-puff atmospheric dispersion model can successfully track the virtually stable, linear or nonlinear release rate after being iterated about 10 times. The standard error of inversion results increases with the true value. Meanwhile extended Kalman filter cannot inverse the height parameter of accident release as interceptive error is too large to converge. Kalman filter constructed from environment monitoring data and Gaussian multi-puff atmospheric dispersion model can be applied to source inversion in nuclear accident which is characterized by static height and position, short and continual release in nuclear facility. Hence it turns out to be an alternative source inversion method in nuclear emergency response. (authors)
RCS Leak Rate Calculation with High Order Least Squares Method
International Nuclear Information System (INIS)
Lee, Jeong Hun; Kang, Young Kyu; Kim, Yang Ki
2010-01-01
As a part of action items for Application of Leak before Break(LBB), RCS Leak Rate Calculation Program is upgraded in Kori unit 3 and 4. For real time monitoring of operators, periodic calculation is needed and corresponding noise reduction scheme is used. This kind of study was issued in Korea, so there have upgraded and used real time RCS Leak Rate Calculation Program in UCN unit 3 and 4 and YGN unit 1 and 2. For reduction of the noise in signals, Linear Regression Method was used in those programs. Linear Regression Method is powerful method for noise reduction. But the system is not static with some alternative flow paths and this makes mixed trend patterns of input signal values. In this condition, the trend of signal and average of Linear Regression are not entirely same pattern. In this study, high order Least squares Method is used to follow the trend of signal and the order of calculation is rearranged. The result of calculation makes reasonable trend and the procedure is physically consistence
International Nuclear Information System (INIS)
Strenge, D.L.; Watson, E.C.; Droppo, J.G.
1976-06-01
The development of technological bases for siting nuclear fuel cycle facilities requires calculational models and computer codes for the evaluation of risks and the assessment of environmental impact of radioactive effluents. A literature search and review of available computer programs revealed that no one program was capable of performing all of the great variety of calculations (i.e., external dose, internal dose, population dose, chronic release, accidental release, etc.). Available literature on existing computer programs has been reviewed and a description of each program reviewed is given
Energy Technology Data Exchange (ETDEWEB)
Strenge, D.L.; Watson, E.C.; Droppo, J.G.
1976-06-01
The development of technological bases for siting nuclear fuel cycle facilities requires calculational models and computer codes for the evaluation of risks and the assessment of environmental impact of radioactive effluents. A literature search and review of available computer programs revealed that no one program was capable of performing all of the great variety of calculations (i.e., external dose, internal dose, population dose, chronic release, accidental release, etc.). Available literature on existing computer programs has been reviewed and a description of each program reviewed is given.
International Nuclear Information System (INIS)
Strenge, D.L.; Peloquin, R.A.
1981-04-01
The computer code HADOC (Hanford Acute Dose Calculations) is described and instructions for its use are presented. The code calculates external dose from air submersion and inhalation doses following acute radionuclide releases. Atmospheric dispersion is calculated using the Hanford model with options to determine maximum conditions. Building wake effects and terrain variation may also be considered. Doses are calculated using dose conversion factor supplied in a data library. Doses are reported for one and fifty year dose commitment periods for the maximum individual and the regional population (within 50 miles). The fractional contribution to dose by radionuclide and exposure mode are also printed if requested
Semiclassical Calculation of Reaction Rate Constants for Homolytical Dissociations
Cardelino, Beatriz H.
2002-01-01
There is growing interest in extending organometallic chemical vapor deposition (OMCVD) to III-V materials that exhibit large thermal decomposition at their optimum growth temperature, such as indium nitride. The group III nitrides are candidate materials for light-emitting diodes and semiconductor lasers operating into the blue and ultraviolet regions. To overcome decomposition of the deposited compound, the reaction must be conducted at high pressures, which causes problems of uniformity. Microgravity may provide the venue for maintaining conditions of laminar flow under high pressure. Since the selection of optimized parameters becomes crucial when performing experiments in microgravity, efforts are presently geared to the development of computational OMCVD models that will couple the reactor fluid dynamics with its chemical kinetics. In the present study, we developed a method to calculate reaction rate constants for the homolytic dissociation of III-V compounds for modeling OMCVD. The method is validated by comparing calculations with experimental reaction rate constants.
A New Method to Calculate Internal Rate of Return
Directory of Open Access Journals (Sweden)
azadeh zandi
2015-09-01
Full Text Available A number of methods have been developed to choose the best capital investment projects such as net present value, internal rate of return and etc. Internal rate of return method is probably the most popular method among managers and investors. But despite the popularity there are serious drawbacks and limitations in this method. After decades of efforts made by economists and experts to improve the method and its shortcomings, Magni in 2010 has revealed a new approach that can solves the most of internal rate of return method problems. This paper present a new method which is originated from Magni’s approach but has much more simple calculations and can resolve all the drawbacks of internal rate of return method.
International Nuclear Information System (INIS)
Lee, J.H.; Atkins, J.E.; McNeish, J.A.; Vallikat, V.
1996-01-01
Simulations were conducted to analyze the sensitivity of the engineered barrier system (EBS) release rate to alternative conceptual models of the advective release from waste packages under dripping fractures. The first conceptual model assumed that dripping water directly contacts the waste form inside the 'failed' waste package, and radionuclides are released from the EBS by advection. The second conceptual model assumed that dripping water is diverted around the 'failed' waste package (because of the presence of corrosion products plugging the perforations) and dripping water is prevented from directly contacting the waste form. In the second model, radionuclides were assumed to transport through the perforations by diffusion, and, once outside the waste package, to be released from the EBS by advection. The second model was to incorporate more realism into the EBS release calculations. For the case with the second EBS release model, most radionuclides had significantly lower peak EBS release rates (from at least one to several orders of magnitude) than with the first EBS release model. The impacts of the alternative EBS release models were greater for the radionuclides with a low solubility (or solubility-limited radionuclides) than for the radionuclides with a high solubility (or waste form dissolution-limited radionuclides). The analyses indicated that the EBS release model representing advection through a 'failed' waste package (the first EBS release model) may be too conservative in predicting the EBS performance. One major implication from this sensitivity study was that a 'failed' waste package container with multiple perforations may still be able to perform effectively as an important barrier to radionuclide release. (author)
Empirical rate equation model and rate calculations of hydrogen generation for Hanford tank waste
International Nuclear Information System (INIS)
HU, T.A.
1999-01-01
Empirical rate equations are derived to estimate hydrogen generation based on chemical reactions, radiolysis of water and organic compounds, and corrosion processes. A comparison of the generation rates observed in the field with the rates calculated for twenty eight tanks shows agreement within a factor of two to three
NAC-1 cask dose rate calculations for LWR spent fuel
International Nuclear Information System (INIS)
CARLSON, A.B.
1999-01-01
A Nuclear Assurance Corporation nuclear fuel transport cask, NAC-1, is being considered as a transport and storage option for spent nuclear fuel located in the B-Cell of the 324 Building. The loaded casks will be shipped to the 200 East Area Interim Storage Area for dry interim storage. Several calculations were performed to assess the photon and neutron dose rates. This report describes the analytical methods, models, and results of this investigation
Analytical model for release calculations in solid thin-foils ISOL targets
Energy Technology Data Exchange (ETDEWEB)
Egoriti, L. [Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); Politecnico di Milano, Department of Energy, CeSNEF-Nuclear Engineering Division, Via Ponzio, 34/3, 20133 Milano (Italy); Boeckx, S. [Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); ICTEAM Inst., Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium); Ghys, L. [Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); Houngbo, D., E-mail: donald.houngbo@sckcen.be [Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); Department of Flow, Heat and Combustion Mechanics, Gent University (UGent), St.-Pietersnieuwstraat 41, B-9000 Gent (Belgium); Popescu, L. [Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium)
2016-10-01
A detailed analytical model has been developed to simulate isotope-release curves from thin-foils ISOL targets. It involves the separate modeling of diffusion and effusion inside the target. The former has been modeled using both first and second Fick's law. The latter, effusion from the surface of the target material to the end of the ionizer, was simulated with the Monte Carlo code MolFlow+. The calculated delay-time distribution for this process was then fitted using a double-exponential function. The release curve obtained from the convolution of diffusion and effusion shows good agreement with experimental data from two different target geometries used at ISOLDE. Moreover, the experimental yields are well reproduced when combining the release fraction with calculated in-target production.
Calculation of gas release from DC and AC arc furnaces in a foundry
Krutyanskii, M. M.; Nekhamin, S. M.; Rebikov, E. M.
2016-12-01
A procedure for the calculation of gas release from arc furnaces is presented. The procedure is based on the stoichiometric ratios of the oxidation of carbon in liquid iron during the oxidation heat period and the oxidation of iron from a steel charge by oxygen in the period of solid charge melting during the gas exchange of the furnace cavity with the external atmosphere.
International Nuclear Information System (INIS)
Kobayashi, Hideo; Yabuta, Hajimu; Katagiri, Hiroshi; Obata, Kazuichi; Kokubu, Morinobu
1982-03-01
Various calculations are made to estimate the distributions of concentration and γ-exposure rate due to a radioactive cloud released from a point source to the atmosphere. In this report, the isopleths of concentration and γ-exposure rate which were calculated are given in graphs to enable rapid prediction of the influence of released radioactive material in the emergency situation. Recently there are facilities which are equipped with a system to display the calculation results on CRT; but such practice is rather rare. By placing the calculated isopleths of reduction scale 1/25000 or 1/50000 on the usual map, any facilities without the CRT system can readily estimate the influence of an accidental release. The graphs of isopleths are given with the release height (11 values of 0 to 200 m at about 20 m intervals) and the atmospheric stability (6 classes) as parameters. Calculations of γ-exposure rates were made using the computer code GAMPUL developed by T. Hayashi and T. Shiraishi. In the calculation of radioactive concentrations and γ-exposure rates, the vertical diffusion depths, σsub(z), exceeding 1000 m are taken to be 1000 m according to the Meteorological Guide for the Safety Analysis of Power Reactor (J.AEC). The comparison between with and without this limitation in σsub(z) is made in the case of downwind axial surface distributions. (author)
Divided Saddle Theory: A New Idea for Rate Constant Calculation.
Daru, János; Stirling, András
2014-03-11
We present a theory of rare events and derive an algorithm to obtain rates from postprocessing the numerical data of a free energy calculation and the corresponding committor analysis. The formalism is based on the division of the saddle region of the free energy profile of the rare event into two adjacent segments called saddle domains. The method is built on sampling the dynamics within these regions: auxiliary rate constants are defined for the saddle domains and the absolute forward and backward rates are obtained by proper reweighting. We call our approach divided saddle theory (DST). An important advantage of our approach is that it requires only standard computational techniques which are available in most molecular dynamics codes. We demonstrate the potential of DST numerically on two examples: rearrangement of alanine-dipeptide (CH3CO-Ala-NHCH3) conformers and the intramolecular Cope reaction of the fluxional barbaralane molecule.
Comparison between calculation methods of dose rates in gynecologic brachytherapy
International Nuclear Information System (INIS)
Vianello, E.A.; Biaggio, M.F.; D R, M.F.; Almeida, C.E. de
1998-01-01
In treatments with radiations for gynecologic tumors is necessary to evaluate the quality of the results obtained by different calculation methods for the dose rates on the points of clinical interest (A, rectal, vesicle). The present work compares the results obtained by two methods. The Manual Calibration Method (MCM) tri dimensional (Vianello E., et.al. 1998), using orthogonal radiographs for each patient in treatment, and the Theraplan/T P-11 planning system (Thratonics International Limited 1990) this last one verified experimentally (Vianello et.al. 1996). The results show that MCM can be used in the physical-clinical practice with a percentile difference comparable at the computerized programs. (Author)
The fast multiple-path NUCTRAN model -- Calculating the radionuclide release from a repository
International Nuclear Information System (INIS)
Romero, L.; Moreno, L.; Neretnieks, I.
1995-01-01
The NUCTRAN model has been applied to the Swedish KBS-3 nuclear waste repository concept, where the migration of radionuclides is through various barriers and pathways. The escape of the nuclides from the canister occurs through a small hole. This hole controls the release of nuclides from the repository. NUCTRAN is a useful tool to calculate the nonstationary transport in a repository for high-level nuclear waste. The advantage of this model is the use of a coarse compartmentalization of the repository, which makes it flexible and easy to adapt to different geometries. The several radionuclide release calculations made with NUCTRAN have shown the capability of this to handle different situations rapidly and easily. The particularity of these calculations is the high accuracy obtained by using a coarse compartmentalization of the Swedish KBS-3 repository and the small requirements of computing time. At short times for short-lived nuclides, the calculated releases are exaggerated. The error can be considerably reduced by an additional subdivision of large compartments into a few compartments
X particle effect for 6Li reaction rates calculations
International Nuclear Information System (INIS)
Kocak, G.; Balantekin, A. B.
2009-01-01
The inferred primordial 6 L i-7 L i abundances are different from standard big bang nucleosynthesis results, 6 L i is 1000 times larger and 7 L i is 3 times smaller than the big bang prediction. In big bang nucleosynthesis, negatively charged massive X particles a possible solution to explain this primordial Li abundances problem [1]. In this study, we consider only X particle effect for nuclear reactions to obtain S-factor and reaction rates for Li. All S-factors calculated within the Optical Model framework for d(α,γ)6 L i system. We showed that the enhancement effect of massive negatively charged X particle for 6 L i system reaction rate.(author)
International Nuclear Information System (INIS)
Ondra, Frantisek; Vasko, Marek; Necas, Vladimir
2012-01-01
The article presents methodology of external exposure calculation for reuse of conditional released materials from decommissioning using VISIPLAN 3D ALARA planning tool. Production of rails has been used as an example application of proposed methodology within the CONRELMAT project. The article presents a methodology for determination of radiological, material, organizational and other conditions for conditionally released materials reuse to ensure that workers and public exposure does not breach the exposure limits during scenario's life cycle (preparation, construction and operation of scenario). The methodology comprises a proposal of following conditions in the view of workers and public exposure: - radionuclide limit concentration of conditionally released materials for specific scenarios and nuclide vectors, - specific deployment of conditionally released materials eventually shielding materials, workers and public during the scenario's life cycle, - organizational measures concerning time of workers or public stay in the vicinity on conditionally released materials for individual performed scenarios and nuclide vectors. The above mentioned steps of proposed methodology have been applied within the CONRELMAT project. Exposure evaluation of workers for rail production is introduced in the article as an example of this application. Exposure calculation using VISIPLAN 3D ALARA planning tool was done within several models. The most exposed profession for scenario was identified. On the basis of this result, an increase of radionuclide concentration in conditional released material was proposed more than two times to 681 Bq/kg without no additional safety or organizational measures being applied. After application of proposed safety and organizational measures (additional shielding, geometry changes and limitation of work duration) it is possible to increase concentration of radionuclide in conditional released material more than ten times to 3092 Bq/kg. Storage
Barber, Duncan Henry
During some postulated accidents at nuclear power stations, fuel cooling may be impaired. In such cases, the fuel heats up and the subsequent increased fission-gas release from the fuel to the gap may result in fuel sheath failure. After fuel sheath failure, the barrier between the coolant and the fuel pellets is lost or impaired, gases and vapours from the fuel-to-sheath gap and other open voids in the fuel pellets can be vented. Gases and steam from the coolant can enter the broken fuel sheath and interact with the fuel pellet surfaces and the fission-product inclusion on the fuel surface (including material at the surface of the fuel matrix). The chemistry of this interaction is an important mechanism to model in order to assess fission-product releases from fuel. Starting in 1995, the computer program SOURCE 2.0 was developed by the Canadian nuclear industry to model fission-product release from fuel during such accidents. SOURCE 2.0 has employed an early thermochemical model of irradiated uranium dioxide fuel developed at the Royal Military College of Canada. To overcome the limitations of computers of that time, the implementation of the RMC model employed lookup tables to pre-calculated equilibrium conditions. In the intervening years, the RMC model has been improved, the power of computers has increased significantly, and thermodynamic subroutine libraries have become available. This thesis is the result of extensive work based on these three factors. A prototype computer program (referred to as SC11) has been developed that uses a thermodynamic subroutine library to calculate thermodynamic equilibria using Gibbs energy minimization. The Gibbs energy minimization requires the system temperature (T) and pressure (P), and the inventory of chemical elements (n) in the system. In order to calculate the inventory of chemical elements in the fuel, the list of nuclides and nuclear isomers modelled in SC11 had to be expanded from the list used by SOURCE 2.0. A
International Nuclear Information System (INIS)
Bass, B.R.; Bryan, R.H.; Bryson, J.W.; Merkle, J.G.
1982-01-01
In nonlinear applications of computational fracture mechanics, energy release rate techniques are used increasingly for computing stress intensity parameters of crack configurations. Recently, deLorenzi used the virtual-crack-extension method to derive an analytical expression for the energy release rate that is better suited for three-dimensional calculations than the well-known J-integral. Certain studies of fracture phenomena, such as pressurized-thermal-shock of cracked structures, require that crack tip parameters be determined for combined thermal and mechanical loads. A method is proposed here that modifies the isothermal formulation of deLorenzi to account for thermal strains in cracked bodies. This combined thermo-mechanical formulation of the energy release rate is valid for general fracture, including nonplanar fracture, and applies to thermo-elastic as well as deformation plasticity material models. Two applications of the technique are described here. In the first, semi-elliptical surface cracks in an experimental test vessel are analyzed under elastic-plastic conditions using the finite element method. The second application is a thick-walled test vessel subjected to combined pressure and thermal shock loadings
Variation of the energy release rate as a crack approaches and passes through an elastic inclusion
Li, Rongshun; Chudnovsky, A.
1993-01-01
The variation of the energy release rate (ERP) at the tip of a crack penetrating an elastic inclusion is analyzed using an approach involving modeling the random array of microcracks or other defects by an elastic inclusion with effective elastic properties. Computations are carried out using a finite element procedure. The eight-noded isoparametric serendipity element with the shift of the midpoint to the quarter-point is used to simulate the singularity at the crack tip, and the crack growth is accommodated by implementing a mesh regeneration technique. The ERP values were calculated for various crack tip positions which simulate the process of the crack approaching and penetrating the inclusion.
International Nuclear Information System (INIS)
Kazakov, E.K.; Chernukhina, G.M.
1974-01-01
Results of calculation of the temperature distribution in an annular fuel element at transient thermal conductivity and heat release values are given. The calculation has been carried out by the mesh technique with the third-order boundary conditions for the inner surface assumed and with heat fluxes and temperatures at the zone boundaries to be equal. Three variants of solving the problem of a stationary temperature field are considered for failed fuel elements with clad flaking or cracks. The results obtained show the nonuniformity of the fuel element temperature field to depend strongly on the perturbation parameter at transient thermal conductivity and heat release values. In case of can flaking at a short length, the core temperature rises quickly after flaking. While evaluating superheating, one should take into account the symmetry of can flaking [ru
International Nuclear Information System (INIS)
Thykier-Nielsen, S.
1980-07-01
A brief description is given of the model used at Risoe for calculating the consequences of releases of radioactive material to the atmosphere. The model is based on the Gaussian plume model, and it provides possibilities for calculation of: doses to individuals, collective doses, contamination of the ground, probability distribution of doses, and the consequences of doses for give dose-risk relationships. The model is implemented as a computer program PLUCON2, written in ALGOL for the Burroughs B6700 computer at Risoe. A short description of PLUCON2 is given. (author)
International Nuclear Information System (INIS)
Smith, P.D.
1978-02-01
A special purpose computer program, TRAFIC, is presented for calculating the release of metallic fission products from an HTGR core. The program is based upon Fick's law of diffusion for radioactive species. One-dimensional transient diffusion calculations are performed for the coated fuel particles and for the structural graphite web. A quasi steady-state calculation is performed for the fuel rod matrix material. The model accounts for nonlinear adsorption behavior in the fuel rod gap and on the coolant hole boundary. The TRAFIC program is designed to operate in a core survey mode; that is, it performs many repetitive calculations for a large number of spatial locations in the core. This is necessary in order to obtain an accurate volume integrated release. For this reason the program has been designed with calculational efficiency as one of its main objectives. A highly efficient numerical method is used in the solution. The method makes use of the Duhamel superposition principle to eliminate interior spatial solutions from consideration. Linear response functions relating the concentrations and mass fluxes on the boundaries of a homogeneous region are derived. Multiple regions are numerically coupled through interface conditions. Algebraic elimination is used to reduce the equations as far as possible. The problem reduces to two nonlinear equations in two unknowns, which are solved using a Newton Raphson technique
Development and application of the PBMR fission product release calculation model
International Nuclear Information System (INIS)
Merwe, J.J. van der; Clifford, I.
2008-01-01
At PBMR, long-lived fission product release from spherical fuel spheres is calculated using the German legacy software product GETTER. GETTER is a good tool when performing calculations for fuel spheres under controlled operating conditions, including irradiation tests and post-irradiation heat-up experiments. It has proved itself as a versatile reactor analysis tool, but is rather cumbersome when used for accident and sensitivity analysis. Developments in depressurized loss of forced cooling (DLOFC) accident analysis using GETTER led to the creation of FIssion Product RElease under accident (X) conditions (FIPREX), and later FIPREX-GETTER. FIPREX-GETTER is designed as a wrapper around GETTER so that calculations can be carried out for large numbers of fuel spheres with design and operating parameters that can be stochastically varied. This allows full Monte Carlo sensitivity analyses to be performed for representative cores containing many fuel spheres. The development process and application of FIPREX-GETTER in reactor analysis at PBMR is explained and the requirements for future developments of the code are discussed. Results are presented for a sample PBMR core design under normal operating conditions as well as a suite of design-base accident events, illustrating the functionality of FIPREX-GETTER. Monte Carlo sensitivity analysis principles are explained and presented for each calculation type. The plan and current status of verification and validation (V and V) is described. This is an important and necessary process for all software and calculation model development at PBMR
Determination of the sterile release rate for stopping growing age-structured populations
International Nuclear Information System (INIS)
Barclay, Hugh John
2016-01-01
A freely-growing age-structured population was modelled for growth and control by sterile male releases. Equilibrium populations yield critical sterile male release rates that would hold the population at equilibrium. It is shown here that these rates may be different from the release rates required to stop a growing population and bring it to an equilibrium. A computer simulation was constructed of this population and a parameter sensitivity analysis graphed the effects on the required sterile male release rate of fertility, mating delay in adult females, net juvenile survivorship, three adult survivorship curves, the time spent in the juvenile stages, and total life span. The adult survivorship curves had the greatest effect on the required sterile release rate for population elimination. The required release rate was also determined for Ceratitis capitata (Wiedemann) using survivorship and fertility data from a laboratory strain. The concepts of over-flooding ratio and release ratio were discussed and quantified for the cases above. (author)
Directory of Open Access Journals (Sweden)
Sabera eKhatun
2014-06-01
Full Text Available In recent years natural polymers have been widely used, because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5%, 10%, 15%, 20%, 25% and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr’s Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR, Differential Scanning Calorimetry (DSC and Scanning Electron Microscopy (SEM studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37oC ± 0.5 temperature, for 8 hours. All the formulations comply with both BP and USP requirements, but among all the formulations F-1 (5% of Water hyacinth was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations.
Khatun, Sabera; Sutradhar, Kumar B
2014-01-01
In recent years natural polymers have been widely used because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5, 10, 15, 20, 25 and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr's Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37°C ± 0.5 temperature for 8 h. Though all the formulations comply with both BP and USP requirements, formulation F-1 (5% of Water hyacinth) was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell, and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations.
Approaches to proton single-event rate calculations
International Nuclear Information System (INIS)
Petersen, E.L.
1996-01-01
This article discusses the fundamentals of proton-induced single-event upsets and of the various methods that have been developed to calculate upset rates. Two types of approaches are used based on nuclear-reaction analysis. Several aspects can be analyzed using analytic methods, but a complete description is not available. The paper presents an analytic description for the component due to elastic-scattering recoils. There have been a number of studies made using Monte Carlo methods. These can completely describe the reaction processes, including the effect of nuclear reactions occurring outside the device-sensitive volume. They have not included the elastic-scattering processes. The article describes the semiempirical approaches that are most widely used. The quality of previous upset predictions relative to space observations is discussed and leads to comments about the desired quality of future predictions. Brief sections treat the possible testing limitation due to total ionizing dose effects, the relationship of proton and heavy-ion upsets, upsets due to direct proton ionization, and relative proton and cosmic-ray upset rates
Realistic methods for calculating the releases and consequences of a large LOCA
International Nuclear Information System (INIS)
Stephenson, W.; Dutton, L.M.C.; Handy, B.J.; Smedley, C.
1992-01-01
This report describes a calculational route to predict realistic radiological consequences for a successfully terminated large-loss-of-coolant accident (LOCA) at a pressurized-water reactor (PWR). All steps in the calculational route are considered. For each one, a brief comment is made on the significant differences between the methods of calculation that were identified in the benchmark studies and recommendations are made for the methods and data for carrying out realistic calculations. These are based on the best supportable methods and data and the technical basis for each recommendation is given. Where the lack of well-validated methods or data means that the most realistic method that can be justified is considered to be very conservative, the need for further research is identified. The behaviour of inorganic iodine and the removal of aerosols from the atmosphere of the reactor building are identified as areas of particular importance. Where the retention of radioactivity is sensitive to design features, these are identified and, for the most importance features, the impact of different designs on the release of activity is indicated. The predictions of the proposed model are calculated for each stage and compared with the releases of activity predicted by the licensing methods that were used in the earlier benchmark studies. The conservative nature of the latter is confirmed. Methods and data are also presented for calculating the resulting doses to members of the public of the National Radiological Protection Boards as a result of work carried out by several national bodies in the UK. Other, equally acceptable, models are used in other countries of the Community and some examples are given
Conversion factors for estimating release rate of gaseous radioactivity by an aerial survey
International Nuclear Information System (INIS)
Saito, Kimiaki; Moriuchi, Shigeru
1988-02-01
Conversion factors necessary for estimating release rate of gaseous radioactivity by an aerial survey are presented. The conversion factors were determined based on calculation assuming a Gaussian plume model as a function of atmospheric stability, down-wind distance and flight height. First, the conversion factors for plumes emitting mono-energy gamma rays were calculated, then, conversion factors were constructed through convolution for the radionuclides essential in an accident of a nuclear reactor, and for mixtures of these radionuclides considering elapsed time after shutdown. These conversion factors are shown in figures, and also polynomial expressions of the conversion factors as a function of height have been decided with the least-squares method. A user can easily obtain proper conversion factors from data shown here. (author)
A set of integrated environmental transport and diffusion models for calculating hazardous releases
International Nuclear Information System (INIS)
Pepper, D.W.
1996-01-01
A set of numerical transport and dispersion models is incorporated within a graphical interface shell to predict hazardous material released into the environment. The visual shell (EnviroView) consists of an object-oriented knowledge base, which is used for inventory control, site mapping and orientation, and monitoring of materials. Graphical displays of detailed sites, building locations, floor plans, and three-dimensional views within a room are available to the user using a point and click interface. In the event of a release to the environment, the user can choose from a selection of analytical, finite element, finite volume, and boundary element methods, which calculate atmospheric transport, groundwater transport, and dispersion within a building interior. The program runs on 486 personal computers under WINDOWS
Sherbini, S; Tamasanis, D; Sykes, J; Porter, S W
1986-12-01
A program was developed to calculate the exposure rate resulting from airborne gases inside a reactor containment building. The calculations were performed at the location of a wall-mounted area radiation monitor. The program uses Monte Carlo techniques and accounts for both the direct and scattered components of the radiation field at the detector. The scattered component was found to contribute about 30% of the total exposure rate at 50 keV and dropped to about 7% at 2000 keV. The results of the calculations were normalized to unit activity per unit volume of air in the containment. This allows the exposure rate readings of the area monitor to be used to estimate the airborne activity in containment in the early phases of an accident. Such estimates, coupled with containment leak rates, provide a method to obtain a release rate for use in offsite dose projection calculations.
Energy Technology Data Exchange (ETDEWEB)
Napier, Bruce A.; Eslinger, Paul W.; Tolstykh, Evgenia I.; Vorobiova, Marina I.; Tokareva, Elena E.; Akhramenko, Boris N.; Krivoschapov, Victor A.; Degteva, Marina O.
2017-11-01
Time-dependent thyroid doses were reconstructed for Techa River Cohort members living near the Mayak production facilities from 131I released to the atmosphere for all relevant exposure pathways. The calculational approach uses four general steps: 1) construct estimates of releases of 131I to the air from production facilities; 2) model the transport of 131I in the air and subsequent deposition on the ground and vegetation; 3) model the accumulation of 131I in soil, water, and food products (environmental media); and 4) calculate individual doses by matching appropriate lifestyle and consumption data for the individual to concentrations of 131I in environmental media. The dose calculations are implemented in a Monte Carlo framework that produces best estimates and confidence intervals of dose time-histories. The 131I contribution was 75-99% of the thyroid dose. The mean total thyroid dose for cohort members was 193 mGy and the median was 53 mGy. Thyroid doses for about 3% of cohort members were larger than 1 Gy. About 7% of children born in 1940-1950 had doses larger than 1 Gy. The uncertainty in the 131I dose estimates is low enough for this approach to be used in regional epidemiological studies.
Screening calculations for radioactive waste releases from non-nuclear facilities
International Nuclear Information System (INIS)
Xu, Shulan; Soederman, Ann-Louis
2009-02-01
A series of screening calculations have been performed to assess the potential radiological consequences of discharges of radioactive substances to the environment arising from waste from non-nuclear practices. Solid waste, as well as liquids that are not poured to the sewer, are incinerated and ashes from incineration and sludge from waste water treatment plants are disposed or reused at municipal disposal facilities. Airborne discharges refer to releases from an incineration facility and liquid discharges refer both to releases from hospitals and laboratories to the sewage system, as well as leakage from waste disposal facilities. The external exposure of workers is estimated both in the waste water treatment plant and at the disposal facility. The calculations follow the philosophy of the IAEA's safety guidance starting with a simple assessment based on very conservative assumptions which may be iteratively refined using progressively more complex models, with more realistic assumptions, as necessary. In the assessments of these types of disposal, with cautious assumptions, carried out in this report we conclude that the radiological impacts on representative individuals in the public are negligible in that they are small with respect to the target dose of 10 μSv/a. A Gaussian plume model was used to estimate the doses from airborne discharges from the incinerator and left a significant safety margin in the results considering the conservative assumptions in the calculations. For the sewage plant workers the realistic approach included a reduction in working hours and the shorter exposure time resulted in maximum doses around 10 μSv/a. The calculations for the waste disposal facility show that the doses are higher or in the range of the target dose. The excess for public exposure is mainly caused by H-3 and C-14. The assumption used in the calculation is that all of the radioactive substances sent to the incineration facility and waste water treatment plant
Variationally Optimized Free-Energy Flooding for Rate Calculation
McCarty, James; Valsson, Omar; Tiwary, Pratyush; Parrinello, Michele
2015-08-01
We propose a new method to obtain kinetic properties of infrequent events from molecular dynamics simulation. The procedure employs a recently introduced variational approach [Valsson and Parrinello, Phys. Rev. Lett. 113, 090601 (2014)] to construct a bias potential as a function of several collective variables that is designed to flood the associated free energy surface up to a predefined level. The resulting bias potential effectively accelerates transitions between metastable free energy minima while ensuring bias-free transition states, thus allowing accurate kinetic rates to be obtained. We test the method on a few illustrative systems for which we obtain an order of magnitude improvement in efficiency relative to previous approaches and several orders of magnitude relative to unbiased molecular dynamics. We expect an even larger improvement in more complex systems. This and the ability of the variational approach to deal efficiently with a large number of collective variables will greatly enhance the scope of these calculations. This work is a vindication of the potential that the variational principle has if applied in innovative ways.
REITP3-Hazard evaluation program for heat release based on thermochemical calculation
Energy Technology Data Exchange (ETDEWEB)
Akutsu, Yoshiaki.; Tamura, Masamitsu. [The University of Tokyo, Tokyo (Japan). School of Engineering; Kawakatsu, Yuichi. [Oji Paper Corp., Tokyo (Japan); Wada, Yuji. [National Institute for Resources and Environment, Tsukuba (Japan); Yoshida, Tadao. [Hosei University, Tokyo (Japan). College of Engineering
1999-06-30
REITP3-A hazard evaluation program for heat release besed on thermochemical calculation has been developed by modifying REITP2 (Revised Estimation of Incompatibility from Thermochemical Properties{sup 2)}. The main modifications are as follows. (1) Reactants are retrieved from the database by chemical formula. (2) As products are listed in an external file, the addition of products and change in order of production can be easily conducted. (3) Part of the program has been changed by considering its use on a personal computer or workstation. These modifications will promote the usefulness of the program for energy hazard evaluation. (author)
Energy Technology Data Exchange (ETDEWEB)
Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.; Lagos, Leonel; Tansel, Berrin
2013-09-05
ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperatures of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.
VANDERVEEN, C; MENGER, NR; LERK, CF
The present study reports on the successful incorporation of a highly soluble drug, procaine HCl, in a programmed-release megaloporous system. This solid two-phase system is composed of housing phase matrix granules (HMG), controlling liquid penetration into the system, and of restraining phase
Inverse modelling of radionuclide release rates using gamma dose rate observations
Hamburger, Thomas; Evangeliou, Nikolaos; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian
2015-04-01
Severe accidents in nuclear power plants such as the historical accident in Chernobyl 1986 or the more recent disaster in the Fukushima Dai-ichi nuclear power plant in 2011 have drastic impacts on the population and environment. Observations and dispersion modelling of the released radionuclides help to assess the regional impact of such nuclear accidents. Modelling the increase of regional radionuclide activity concentrations, which results from nuclear accidents, underlies a multiplicity of uncertainties. One of the most significant uncertainties is the estimation of the source term. That is, the time dependent quantification of the released spectrum of radionuclides during the course of the nuclear accident. The quantification of the source term may either remain uncertain (e.g. Chernobyl, Devell et al., 1995) or rely on estimates given by the operators of the nuclear power plant. Precise measurements are mostly missing due to practical limitations during the accident. The release rates of radionuclides at the accident site can be estimated using inverse modelling (Davoine and Bocquet, 2007). The accuracy of the method depends amongst others on the availability, reliability and the resolution in time and space of the used observations. Radionuclide activity concentrations are observed on a relatively sparse grid and the temporal resolution of available data may be low within the order of hours or a day. Gamma dose rates, on the other hand, are observed routinely on a much denser grid and higher temporal resolution and provide therefore a wider basis for inverse modelling (Saunier et al., 2013). We present a new inversion approach, which combines an atmospheric dispersion model and observations of radionuclide activity concentrations and gamma dose rates to obtain the source term of radionuclides. We use the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998; Stohl et al., 2005) to model the atmospheric transport of the released radionuclides. The
Nuclide release calculation in the near-field of a reference HLW repository
International Nuclear Information System (INIS)
Lee, Youn Myoung; Hwang, Yong Soo; Kang, Chul Hyung
2004-01-01
The HLW-relevant R and D program for disposal of high-level radioactive waste has been carried out at Korea Atomic Energy Research Institute (KAERI) since early 1997 in order to develop a conceptual Korea Reference Repository System for direct disposal of nuclear spent fuel by the end of 2007. A preliminary reference geologic repository concept considering such established criteria and requirements as waste and generic site characteristics in Korea was roughly envisaged in 2003 focusing on the near-field components of the repository system. According to above basic repository concept, which is similar to that of Swedish KBS-3 repository, the spent fuel is first encapsulated in corrosion resistant canisters, even though the material has not yet been determined, and then emplaced into the deposition holes surrounded by high density bentonite clay in tunnels constructed at a depth of about 500 m in a stable plutonic rock body. Not only to demonstrate how much a reference repository is safe in the generic point of view with several possible scenarios and cases associated with a preliminary repository concept by conducting calculations for nuclide release and transport in the near-field components of the repository, even though enough information has not been available that much yet, but also to show a methodology by which a generic safety assessment could be performed for further development of Korea reference repository concept, nuclide release calculation study strongly seems to be necessary
Energy Technology Data Exchange (ETDEWEB)
Andre, B.; Ducros, G.; Leveque, J.P. [CEA Centre d`Etudes de Grenoble, 38 (France). Dept. de Thermohydraulique et de Physique; Osborne, M.F.; Lorenz, R.A. [Oak Ridge National Lab., TN (United States); Maro, D. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Dept. de Protection de l`Environnement et des Installations
1995-12-31
Experimental programs in the United States and France have followed similar paths in supplying much of the data needed to analyze severe accidents. Both the HI/VI program, conducted at the Oak Ridge National Laboratory (ORNL) under the sponsorship of the U. S. Nuclear Regulatory Commission (NRC), and the HEVA/VERCORS program, supported by IPSN-Commissariat a l`Energie Atomique (CEA) and carried out at the Centre d`Etudes Nucleaires de Grenoble, have studied fission product release from light water reactor (LWR) fuel samples during test sequences representative of severe accidents. Recognizing that more accurate data, i.e., a better defined source term, could reduce the safety margins included in the rather conservative source terms originating from WASH-1400, the primary objective of these programs has been to improve the data base concerning fission product release and behavior at high temperatures. To facilitate the comparison, a model based on fission product diffusion mechanisms that was developed at ORNL and adapted with CEA experimental data is proposed. This CEA model is compared with the ORNL experimental data in a blind test. The two experimental programs used similar techniques in out-of-pile studies. Highly irradiated fuel samples were heated in radiofrequency induction furnaces to very high temperatures (up to 2700 K at ORNL and 2750 K at CEA) in oxidizing (H{sub 2}O), reducing (H{sub 2}) or mixed (H{sub 2}O+H{sub 2}) environments. The experimental parameters, which were chosen from calculated accident scenarios, did not duplicate specific accidents, but rather emphasized careful control of test conditions to facilitate extrapolation of the results to a wide variety of accident situations. This paper presents a broad and consistent database from ORNL and CEA release results obtained independently since the early 1980`S. A comparison of CORSOR and CORSOR Booth calculations, currently used in safety analysis, and the experimental results is presented and
Measurement of semiochemical release rates with a dedicated environmental control system
Heping Zhu; Harold W. Thistle; Christopher M. Ranger; Hongping Zhou; Brian L. Strom
2015-01-01
Insect semiochemical dispensers are commonly deployed under variable environmental conditions over a specified period. Predictions of their longevity are hampered by a lack of methods to accurately monitor and predict how primary variables affect semiochemical release rate. A system was constructed to precisely determine semiochemical release rates under...
Okamoto, H; Taguchi, H; Iida, K; Danjo, K
2001-12-13
We examined the penetration rate of lidocaine (LC) through excised oral mucosa from hamster cheek pouch and the in vitro release rate of LC from film dosage forms with hydroxypropylcellulose (HPC) as a film base. Addition of glycyrrhizic acid (GL) to the HPC films increased the LC release rate almost GL-content-dependently, while an optimum GL content was observed for the LC penetration rate. No LC penetration was observed from an acidic aqueous solution (pH 3.4) of LC, suggesting only unionized LC can substantially penetrate through the mucosa. A significant relationship between the penetration rate of LC and the release rate of unionized LC was found, suggesting that the in vitro dissolution study is a useful tool to predict the penetration rate taking the unionized drug fraction into consideration.
Study on crack propagation of adhesively bonded DCB for aluminum foam using energy release rate
Energy Technology Data Exchange (ETDEWEB)
Bang, Hye Jin; Lee, Sang Kyo; Cho, Chong Du [Inha University, Incheon (Korea, Republic of); Cho, Jae Ung [Kongju National University, Choenan (Korea, Republic of)
2015-01-15
Aluminum foam with initial crack, which has a closed cell form adhesively bonded, is studied to compare and analyze the crack propagation behavior by using both experimental and finite element analysis techniques. The specimen is loaded in Mode I type of fracture as 15 mm/min speed of a displacement control method. The experimental results were used to accommodate the finite element analysis performed with commercial software ABAQUS 6.10. First, using a video recording, five steps of experiment were selected at random and then the energy release rate was calculated. The estimated energy release rate was then used as fracture energy into the finite element analysis. Comparing the experimental axial load-displacement graphs and the finite element analysis results, roughly equivalent peak values were observed in the cohesive strength of the aluminum foam double cantilever beam. However, force versus displacement patterns showed somewhat different: little deformation was observed in aluminum foam, whereas adhesive parts in double cantilever beam were significantly deformed.
Current evaluation of dose rate calculation - analytical method
International Nuclear Information System (INIS)
Tello, Marcos; Vilhena, Marco Tulio
1996-01-01
The accuracy of the dose calculations based on pencil beam formulas such as Fokker-Plank equations and Fermi equations for charged particle transport are studied and a methodology to solve the Boltzmann transport equation is suggested
Calculation of the decay rate of the proton
International Nuclear Information System (INIS)
Ross, D.A.
1980-01-01
The SU(5) model of Georgi and Glashow is used for these calculations, being the simplist such model and since the point of unification of the strong, weak and electromagnetic interactions is very intensitive to the exact details of the model provided it obeys the desert hypothesis. The broad features of the calculation are common to all models with a dessert between the W-mass and unification
Screening calculations for radioactive waste releases from non-nuclear facilities
Energy Technology Data Exchange (ETDEWEB)
Shulan Xu; Soederman, Ann-Louis
2009-02-15
A series of screening calculations have been performed to assess the potential radiological consequences of discharges of radioactive substances to the environment arising from waste from non-nuclear practices. Solid waste, as well as liquids that are not poured to the sewer, are incinerated and ashes from incineration and sludge from waste water treatment plants are disposed or reused at municipal disposal facilities. Airborne discharges refer to releases from an incineration facility and liquid discharges refer both to releases from hospitals and laboratories to the sewage system, as well as leakage from waste disposal facilities. The external exposure of workers is estimated both in the waste water treatment plant and at the disposal facility. The calculations follow the philosophy of the IAEA's safety guidance starting with a simple assessment based on very conservative assumptions which may be iteratively refined using progressively more complex models, with more realistic assumptions, as necessary. In the assessments of these types of disposal, with cautious assumptions, carried out in this report we conclude that the radiological impacts on representative individuals in the public are negligible in that they are small with respect to the target dose of 10 muSv/a. A Gaussian plume model was used to estimate the doses from airborne discharges from the incinerator and left a significant safety margin in the results considering the conservative assumptions in the calculations. For the sewage plant workers the realistic approach included a reduction in working hours and the shorter exposure time resulted in maximum doses around 10 muSv/a. The calculations for the waste disposal facility show that the doses are higher or in the range of the target dose. The excess for public exposure is mainly caused by H-3 and C-14. The assumption used in the calculation is that all of the radioactive substances sent to the incineration facility and waste water treatment
ASSESSMENT OF RELEASE RATES FOR RADIONUCLIDES IN ACTIVATED CONCRETE.
Energy Technology Data Exchange (ETDEWEB)
SULLIVAN,T.M.
2003-08-23
The Maine Yankee (MY) nuclear power plant is undergoing the process of decontamination and decommissioning (D&D). Part of the process requires analyses that demonstrate that any radioactivity that remains after D&D will not cause exposure to radioactive contaminants to exceed acceptable limits. This requires knowledge of the distribution of radionuclides in the remaining material and their potential release mechanisms from the material to the contacting groundwater. In this study the concern involves radionuclide contamination in activated concrete in the ICI Sump below the containment building. Figures 1-3 are schematic representations of the ICI Sump. Figure 2 and 3 contain the relevant dimensions needed for the analysis. The key features of Figures 2 and 3 are the 3/8-inch carbon steel liner that isolates the activated concrete from the pit and the concrete wall, which is between 7 feet and 7 feet 2 inches thick. During operations, a small neutron flux from the reactor activated the carbon steel liner and the concrete outside the liner. Current MY plans call for filling the ICI sump with compacted sand.
Critical groups vs. representative person: dose calculations due to predicted releases from USEXA
Energy Technology Data Exchange (ETDEWEB)
Ferreira, N.L.D., E-mail: nelson.luiz@ctmsp.mar.mil.br [Centro Tecnologico da Marinha (CTM/SP), Sao Paulo, SP (Brazil); Rochedo, E.R.R., E-mail: elainerochedo@gmail.com [Instituto de Radiprotecao e Dosimetria (lRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Mazzilli, B.P., E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2013-07-01
The critical group cf Centro Experimental Aramar (CEA) site was previously defined based 00 the effluents releases to the environment resulting from the facilities already operational at CEA. In this work, effective doses are calculated to members of the critical group considering the predicted potential uranium releases from the Uranium Hexafluoride Production Plant (USEXA). Basically, this work studies the behavior of the resulting doses related to the type of habit data used in the analysis and two distinct situations are considered: (a) the utilization of average values obtained from official institutions (IBGE, IEA-SP, CNEN, IAEA) and from the literature; and (b) the utilization of the 95{sup tb} percentile of the values derived from distributions fit to the obtained habit data. The first option corresponds to the way that data was used for the definition of the critical group of CEA done in former assessments, while the second one corresponds to the use of data in deterministic assessments, as recommended by ICRP to estimate doses to the so--called 'representative person' . (author)
Critical groups vs. representative person: dose calculations due to predicted releases from USEXA
International Nuclear Information System (INIS)
Ferreira, N.L.D.; Rochedo, E.R.R.; Mazzilli, B.P.
2013-01-01
The critical group cf Centro Experimental Aramar (CEA) site was previously defined based 00 the effluents releases to the environment resulting from the facilities already operational at CEA. In this work, effective doses are calculated to members of the critical group considering the predicted potential uranium releases from the Uranium Hexafluoride Production Plant (USEXA). Basically, this work studies the behavior of the resulting doses related to the type of habit data used in the analysis and two distinct situations are considered: (a) the utilization of average values obtained from official institutions (IBGE, IEA-SP, CNEN, IAEA) and from the literature; and (b) the utilization of the 95 tb percentile of the values derived from distributions fit to the obtained habit data. The first option corresponds to the way that data was used for the definition of the critical group of CEA done in former assessments, while the second one corresponds to the use of data in deterministic assessments, as recommended by ICRP to estimate doses to the so--called 'representative person' . (author)
Calculation of Doses Due to Accidentally Released Plutonium From An LMFBR
Energy Technology Data Exchange (ETDEWEB)
Fish, B.R.
2001-08-07
Experimental data and analytical models that should be considered in assessing the transport properties of plutonium aerosols following a hypothetical reactor accident have been examined. Behaviors of released airborne materials within the reactor containment systems, as well as in the atmosphere near the reactor site boundaries, have been semiquantitatively predicted from experimental data and analytical models. The fundamental chemistry of plutonium as it may be applied in biological systems has been used to prepare models related to the intake and metabolism of plutonium dioxide, the fuel material of interest. Attempts have been made to calculate the possible doses from plutonium aerosols for a typical analyzed release in order to evaluate the magnitude of the internal exposure hazards that might exist in the vicinity of the reactor after a hypothetical LMFBR (Liquid-Metal Fast Breeder Reactor) accident. Intake of plutonium (using data for {sup 239}Pu as an example) and its distribution in the body were treated parametrically without regard to the details of transport pathways in the environment. To the extent possible, dose-response data and models have been reviewed, and an assessment of their adequacy has been made so that recommended or preferred practices could be developed.
Experiment calculated ascertainment of factors affecting the energy release in IGR reactor core
International Nuclear Information System (INIS)
Kurpesheva, A.M.; Zhotabayev, Zh.R.
2006-01-01
Full text: At present energy supply resources problem is important. Nuclear reactors can, of course, solve this problem, but at the same time there is another issue, concerning safety exploitation of nuclear reactors. That is why, for the last seven years, such experiments as 'Investigation of the processes, conducting severe accidents with core melting' are being carried out at our IGR (impulse graphite reactor) reactor. Leaving out other difficulties of such experiments, it is necessary to notice, that such experiments require more accurate IGR core energy release calculations. The final aim of the present research is verification and correction of the existing method or creation of new method of IGR core energy release calculation. IGR reactor is unique and there is no the same reactor in the world. Therefore, application of the other research reactor methods here is quite useful. This work is based on evaluation of factors affecting core energy release (physical weight of experimental device, different configuration of reactor core, i.e. location of absorbers, initial temperature of core, etc), as well as interference of absorbers group. As it is known, energy release is a value of integral reactor power. During experiments with rays, Reactor power depends on currents of ion production chambers (IPC), located round the core. It is worth to notice that each ion production chamber (IPC) in the same start-up has its own ratio coefficient between IPC current and reactor present power. This task is complicated due to 'IPC current - reactor power' ratio coefficients, that change continuously, probably, because of new loading of experimental facility and different position of control rods. That is why, in order to try about reactor power, before every start-up, we have to re-determine the 'IPC current - reactor power' ratio coefficients for each ion production chamber (IPC). Therefore, the present work will investigate the behavior of ratio coefficient within the
42 CFR 413.312 - Methodology for calculating rates.
2010-10-01
... Determined Payment Rates for Low-Volume Skilled Nursing Facilities, for Cost Reporting Periods Beginning... routine service cost limits; (ii) A wage index to adjust for area wage differences; and (iii) The most... of rates published in the Federal Register under the authority of § 413.320, CMS announces the wage...
Three-dimensional calculations of charge neutralization by neutral gas release
International Nuclear Information System (INIS)
Mandell, M.J.; Jongeward, G.A.; Katz, I.
1993-01-01
There have been numerous observations of high rocket or spacecraft potentials, both positive and negative, and both naturally and artificially induced, being neutralized during thruster firings. Two current studies, CHARGE-2B (positive polarity) and SPEAR3 (negative polarity), attempt a more systematic exploration of this phenomenon. The authors present here calculations performed in support of the SPEAR-3 program. (1) Conventional phenomenology of breakdown is applied to the three-dimensional system formed by the electrostatic potential and plume density fields. Using real cross sections, they calculate the paths along which the nozzle plume can support breakdown. This leads to a recommendation that the higher flow rate on SPEAR-3 be 2 g/s of argon, equal to the CHARGE-2B flow rate. (2) In a laboratory chamber, conditions (pressure of ∼ 2 x 10 - 5 torr) favor breakdown of the positive (electron-collecting) sheath for SPEAR-3 geometry. Three-dimensional calculations illustrate the evolution of the space charge and potential structure during the breakdown process. These calculations demonstrate the ability to apply accepted phenomenology to real systems with three dimensional electrostatic potential fields, space charge fields, and neutral density fields, including magnetic field effects and real cross-section data
International Nuclear Information System (INIS)
Cardile, F.P.; Bangart, R.L.; Collins, J.T.
1978-06-01
The Intergovernmental Maritime Consultative Organization IMCO) is currently preparing guidelines concerning the safety of nuclear-powered merchant ships. An important aspect of these guidelines is the determination of the releases of radioactive material in effluents from these ships and the control exercised by the ships over these releases. To provide a method for the determination of these releases, the NRC staff has developed a computerized model, the NMS-GEFF Code, which is described in the following chapters. The NMS-GEFF Code calculates releases of radioactive material in gaseous effluents for nuclear-powered merchant ships using pressurized water reactors
International Nuclear Information System (INIS)
2002-01-01
1 - Description of program or function: IODES is a dynamic linear compartment model of the global iodine cycle which estimates long-term doses and dose commitments to the world population from releases of 129 I to the environment. The global environment is divided into different compartments comprising the atmosphere, hydrosphere, lithosphere, and terrestrial biosphere. The global transport of iodine is described by means of time-invariant fractional transfer rates between the environmental compartments. The fractional transfer rates for 129 I are determined primarily from available data on compartment inventories and fluxes for naturally occurring stable iodine and from data on the global hydrologic cycle. The dose to the world population is estimated from the calculated compartment inventories of 129 I, the known compartment inventories of stable iodine, a pathway analysis of the intake of iodine by a reference individual, dose conversion factors for inhalation and ingestion, and an estimate of the world population. For an assumed constant population of 12.21 billion beyond the year 2075, the estimated population dose commitment is 2 x 105 man-rem/Ci. 2 - Methods: IODES calculates 129 I inventories in the different environmental compartments and individual and population doses as a function of time after a release to the environment by solving a set of simultaneous first-order linear differential equations using numerical methods. 3 - Restrictions on the complexity of the problem: - The subroutine LSODE for solving the differential equations is provided online at the ORNL computer center and, thus, is not included in the IODES code package. If the LSODE routine is not available to the user, then an appropriate differential equation routine must be supplied by the user, and the initialization of parameters and the call statement for LSODE in the main program must be changed accordingly
Evaluation of olibanum and its resin as rate controlling matrix for controlled release of diclofenac
Chowdary KPR; Mohapatra P; Murali Krishna M
2006-01-01
Olibanum and its resin and carbohydrate fractions were evaluated as rate controlling matrix materials in tablets for controlled release of diclofenac. Diclofenac matrix tablets were formulated employing olibanum and its resin and carbohydrate fractions in different concentrations and the tablets were evaluated for various tablet characters including drug release kinetics and mechanism. Olibanum and its resin component exhibited excellent retarding effect on drug release from the matrix tablet...
International Nuclear Information System (INIS)
Ichikawa, Yoichi; Shikata, Hiroshi; Ishida, Kenji; Ohba, Tachimori.
1981-01-01
The measured γ-exposure rate around nuclear power plants is due mainly to natural causes and radioactive clouds emitted from the plants. An exposure calculation method based on puff model has been already proposed to identify the plant contributions and to estimate values in response to short-term fluctuations of meteorological condition and the release rate. However, the calculation method by this model consumes a lot of computer time, since the calculation requires a three-dimensional integration of the distribution of the concentration from each puff. Hence, we propose a simplified method using approximate polynominal equations and interpolations. The computer time needed for the calculation with the simplified method is reduced to 1/30 of that required by the previous method. The calculation results by simplified method are compared with those by the previous method and with the measured exposure rate less natural background. The results of two different methods are in good agreement. The calculated exposure rate is within the range from half to twice as much as the measured exposure rate less background. (author)
Hindered disulfide bonds to regulate release rate of model drug from mesoporous silica.
Nadrah, Peter; Maver, Uroš; Jemec, Anita; Tišler, Tatjana; Bele, Marjan; Dražić, Goran; Benčina, Mojca; Pintar, Albin; Planinšek, Odon; Gaberšček, Miran
2013-05-01
With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.
An atomistic methodology of energy release rate for graphene at nanoscale
International Nuclear Information System (INIS)
Zhang, Zhen; Lee, James D.; Wang, Xianqiao
2014-01-01
Graphene is a single layer of carbon atoms packed into a honeycomb architecture, serving as a fundamental building block for electric devices. Understanding the fracture mechanism of graphene under various conditions is crucial for tailoring the electrical and mechanical properties of graphene-based devices at atomic scale. Although most of the fracture mechanics concepts, such as stress intensity factors, are not applicable in molecular dynamics simulation, energy release rate still remains to be a feasible and crucial physical quantity to characterize the fracture mechanical property of materials at nanoscale. This work introduces an atomistic simulation methodology, based on the energy release rate, as a tool to unveil the fracture mechanism of graphene at nanoscale. This methodology can be easily extended to any atomistic material system. We have investigated both opening mode and mixed mode at different temperatures. Simulation results show that the critical energy release rate of graphene is independent of initial crack length at low temperature. Graphene with inclined pre-crack possesses higher fracture strength and fracture deformation but smaller critical energy release rate compared with the graphene with vertical pre-crack. Owing to its anisotropy, graphene with armchair chirality always has greater critical energy release rate than graphene with zigzag chirality. The increase of temperature leads to the reduction of fracture strength, fracture deformation, and the critical energy release rate of graphene. Also, higher temperature brings higher randomness of energy release rate of graphene under a variety of predefined crack lengths. The energy release rate is independent of the strain rate as long as the strain rate is small enough
Calculating Outcrossing Rates used in Decision Support Systems for Ships
DEFF Research Database (Denmark)
Nielsen, Ulrik Dam
2008-01-01
Onboard decision support systems (DSS) are used to increase the operational safety of ships. Ideally, DSS can estimate - in the statistical sense - future ship responses on a time scale of the order of 1-3 hours taking into account speed and course changes. The calculations depend on both...... analysis, and the paper derives and describes the main ideas. The concept is illustrated by an example, where the limit state of a non-linear ship response is considered. The results from the parallel system analysis are in agreement with corresponding Monte Carlo simulations. However, the computational...
Calculation of multigroup reaction rates for the Ghana Research ...
African Journals Online (AJOL)
The discrete ordinate spatial model, which pro-vides solution to the differential form of the transport equation by the Carlson-SN (N=4) approach was adopted to solve the Ludwig-Boltzmann multigroup neutron transport equation for this analysis. The results show that for any fissile resonance absorber, the reaction rates ...
Exact comparison of dose rate measurements and calculation of TN12/2 packages
International Nuclear Information System (INIS)
Taniuchi, H.; Matsuda, F.
1998-01-01
Both of dose rate measurements of TN 12/2 package and calculations by Monte Carlo code MORSE in SCALE code system and MCNP were performed to evaluate the difference between the measurement and the calculation and finding out the cause of the difference. The calculated gamma-ray dose rates agreed well with measured ones, but calculated neutron dose rates overestimated more than a factor of 1.7. When considering the cause of the difference and applying the modification into the neutron calculation, the calculated neutron dose rates become to agree well, and the factor decreased to around 1.3. (authors)
International Nuclear Information System (INIS)
1994-12-01
This document contains compiled data from the DOE Handbook on Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear facilities. Source data and example facilities utilized, such as the Plutonium Recovery Facility, are included
Measurement of very low release rates of corrosion products in high temperature water
International Nuclear Information System (INIS)
Hermansson, H.-P.; Falk, I.
1984-01-01
A radiotracer technique has been developed for the measurement of release rates from nuclear reactor materials and it has been tested in a number of experiments. THis article, which forms the first part in a series, describes the experimental loop, the experimental technique and the preliminary results. Experiments were carried out on 18Cr8Ni stainless steel and on Inconel X750 in BWR primary system and feed water environments. The result show that a steady state in the release rate is achieved after operation for approximately 600 h. The release rate depends on the elemental concentration in the material and on the chemical and physical environments. Typical release rates for an 18Cr8Ni stainless steel and Inconel X750 in a BWR primary system environment were found to be 5 mdm and 8 mdm respectively. (Authors)
Sample size calculation for comparing two negative binomial rates.
Zhu, Haiyuan; Lakkis, Hassan
2014-02-10
Negative binomial model has been increasingly used to model the count data in recent clinical trials. It is frequently chosen over Poisson model in cases of overdispersed count data that are commonly seen in clinical trials. One of the challenges of applying negative binomial model in clinical trial design is the sample size estimation. In practice, simulation methods have been frequently used for sample size estimation. In this paper, an explicit formula is developed to calculate sample size based on the negative binomial model. Depending on different approaches to estimate the variance under null hypothesis, three variations of the sample size formula are proposed and discussed. Important characteristics of the formula include its accuracy and its ability to explicitly incorporate dispersion parameter and exposure time. The performance of the formula with each variation is assessed using simulations. Copyright © 2013 John Wiley & Sons, Ltd.
Secondary standard dosimetry system with automatic dose/rate calculation
International Nuclear Information System (INIS)
Duftschmid, K.E.; Bernhart, J.; Stehno, G.; Klosch, W.
1980-01-01
A versatile and automated secondary standard instrument has been designed for quick and accurate dose/rate measurement in a wide range of radiation intensity and quality (between 1 μR and 100 kR; 0.2 nC/kg - 20C/kg) for protection and therapy level dosimetry. The system is based on a series of secondary standard ionization chambers connected to a precision digital current integrator with microprocessor circuitry for data evaluation and control. Input of measurement parameters and calibration factors stored in an exchangeable memory chip provide computation of dose/rate values in the desired units. The ionization chambers provide excellent long-term stability and energy response and can be used with internal check sources to test validity of calibration. The system is a useful tool particularly for daily measurements in a secondary standard dosimetry laboratory or radiation therapy center. (H.K.)
Calculation of turnover rates in stable-isotope studies
International Nuclear Information System (INIS)
Wootton, R.; Ford, G.C.; Cheng, K.N.; Halliday, D.
1985-01-01
In a comparison of glucose turnover measured with 2 H-glucose and with 13 C-glucose Tserng and Kalhan used five apparently different equations and obtained conflicting answers. There is, however, no difference in principle between the use of a stable isotope as a tracer and the use of a radioactive isotope, and the rate of appearance of tracee in a steady-state system (the turnover) can therefore be shown to be proportional to the equilibrium dilution of the infused tracer. Because the sensitivity of measurement of this dilution made using a gas chromatograph-mass spectrometer is lower than that made by radioactivity measurement, the contribution to the measured turnover rate due to the infusate cannot be neglected, as it usually is in radioisotope work. A convenient calibration curve to establish this dilution is the mole ratio of the pure infusate against the area ratio for the relevant ions. Tserng and Kalhan's apparently conflicting results for glucose-turnover using 13 C-glucose as the tracer can all be shown to amount to approximately 11.6 μmol min -1 kg -1 . This value is only slightly lower (0.05 2 H-glucose as the tracer and supports the use of 13 C-glucose as an alternative. (author)
Calculations of Fission Gas Release During Ramp Tests Using Copernic Code
Energy Technology Data Exchange (ETDEWEB)
Tong, Liu [Nuclear Fuel R and D Center, China Nuclear Power Technology Research Institute (CNPRI) (China)
2013-03-15
The report performed under IAEA research contract No.15951 describes the results of fuel performance evaluation of LWR fuel rods operated at ramp conditions using the COPERNIC code developed by AREVA. The experimental data from the Third Riso Fission Gas Project and the Studsvik SUPER-RAMP Project presented in the IFPE database of the OECD/NEA has been utilized for assessing the code itself during simulation of fission gas release (FGR). Standard code models for LWR fuel were used in simulations with parameters set properly in accordance with relevant test reports. With the help of data adjustment, the input power histories are restructured to fit the real ones, so as to ensure the validity of FGR prediction. The results obtained by COPERNIC show that different models lead to diverse predictions and discrepancies. By comparison, the COPERNIC V2.2 model (95% Upper bound) is selected as the standard FGR model in this report and the FGR phenomenon is properly simulated by the code. To interpret the large discrepancies of some certain PK rods, the burst effect of FGR which is taken into consideration in COPERNIC is described and the influence of the input power histories is extrapolated. In addition, the real-time tracking capability of COPERNIC is tested against experimental data. In the process of investigation, two main dominant factors influencing the measured gas release rate are described and different mechanisms are analyzed. With the limited predicting capacity, accurate predictions cannot be carried out on abrupt changes of FGR during ramp tests by COPERNIC and improvements may be necessary to some relevant models. (author)
Photoionization cross sections and Auger rates calculated by many-body perturbation theory
International Nuclear Information System (INIS)
Kelly, H.P.
1976-01-01
Methods for applying the many body perturbation theory to atomic calculations are discussed with particular emphasis on calculation of photoionization cross sections and Auger rates. Topics covered include: Rayleigh--Schroedinger theory; many body perturbation theory; calculations of photoionization cross sections; and Auger rates
Accurate quantum calculations of the reaction rates for H/D+ CH4
Harrevelt, R. van; Nyman, G.; Manthe, U.
2007-01-01
In previous work [T. Wu, H. J. Werner, and U. Manthe, Science 306, 2227 (2004)], accurate quantum reaction rate calculations of the rate constant for the H+CH4 -> CH3+H-2 reaction have been presented. Both the electronic structure calculations and the nuclear dynamics calculations are converged with
International Nuclear Information System (INIS)
Jones, J.A.
1980-03-01
Radioactive material may be discharged to atmosphere in small quantities during the normal operation of a nuclear installation as part of a considered waste management practice. Estimates of the individual and collective dose equivalent rates resulting from such a discharge are required in a number of contexts: for example, in assessing compliance with dose limits, in estimating the radiological impact of the discharge and as an input into optimisation studies. The suite of programs which has been developed to undertake such calculations is made up of a number of independent modules one of which, ESCLOUD, is described in this report. The ESCLOUD program evaluates, as a function of distance and direction from the release point, the air concentration, deposition rate and external β and γ doses from airborne and deposited activity. The air concentration and deposition rate can be used as input to other modules for calculating inhalation and ingestion doses. (author)
31 CFR 356.21 - How are awards at the high yield or discount rate calculated?
2010-07-01
... discount rate calculated? 356.21 Section 356.21 Money and Finance: Treasury Regulations Relating to Money... high yield or discount rate calculated? (a) Awards to submitters. We generally prorate bids at the highest accepted yield or discount rate under § 356.20(a)(2) of this part. For example, if 80.15% is the...
Evaluation of rate of swelling and erosion of verapamil (VRP) sustained-release matrix tablets.
Khamanga, Sandile M; Walker, Roderick B
2006-01-01
Tablets manufactured in-house were compared to a marketed sustained-release product of verapamil to investigate the rate of hydration, erosion, and drug-release mechanism by measuring the wet and subsequent dry weights of the products. Swelling and erosion rates depended on the polymer and granulating fluid used, which ultimately pointed to their permeability characteristics. Erosion rate of the marketed product was highest, which suggests that the gel layer that formed around these tablets was weak as opposed to the robust and resistant layers of test products. Anomalous and near zero-order transport mechanisms were dominant in tests and commercial product, respectively.
International Nuclear Information System (INIS)
Xhonneux, Andre; Allelein, Hans-Josef
2014-01-01
The computer codes FRESCO-I, FRESCO-II, PANAMA and SPATRA developed at Forschungszentrum Jülich in Germany in the early 1980s are essential tools to predict the fission product release from spherical fuel elements and the TRISO fuel performance, respectively, under given normal or accidental conditions. These codes are able to calculate a conservative estimation of the source term, i.e. quantity and duration of radionuclide release. Recently, these codes have been reversed engineered, modernized (FORTRAN 95/2003) and combined to form a consistent code named STACY (Source Term Analysis Code System). STACY will later become a module of the V/HTR Code Package (HCP). In addition, further improvements have been implemented to enable more detailed calculations. For example the distinct temperature profile along the pebble radius is now taken into account and coated particle failure rates can be calculated under normal operating conditions. In addition, the absolute fission product release of an V/HTR pebble bed core can be calculated by using the newly developed burnup code Topological Nuclide Transformation (TNT) replacing the former rudimentary approach. As a new functionality, spatially resolved fission product release calculations for normal operating conditions as well as accident conditions can be performed. In case of a full-core calculation, a large number of individual pebbles which follow a random path through the reactor core can be simulated. The history of the individual pebble is recorded, too. Main input data such as spatially resolved neutron fluxes and fluid dynamics data are provided by the VSOP code. Capabilities of the FRESCO-I and SPATRA code which allow for the simulation of the redistribution of fission products within the primary circuit and the deposition of fission products on graphitic and metallic surfaces are also available in STACY. In this paper, details of the STACY model and first results for its application to the 200 MW(th) HTR
Calculation notes in support of ammonia releases from waste tank ventilation systems
International Nuclear Information System (INIS)
Wojdac, L.F.
1996-01-01
Ammonia is generated in waste tanks via the degradation of nitrogen compounds. The ammonia is released from the liquids by a mechanism which is dependent on temperature, pH, ionic strength and ammonia concentration. The release of ammonia to the environment occurs via diffusion of ammonia through a stagnant air mass and into the ventilation system
International Nuclear Information System (INIS)
Edy-Sulistyono
1996-01-01
Burn up dependence of fission gas released and variation power analysis have been conducted using FEMXI-IV computer code program for Pressure Water Reactor Fuel During steady-state condition. The analysis result shows that the fission gas release is sensitive to the fuel temperature, the increasing of burn up and power in the fuel element under irradiation experiment
Energy Technology Data Exchange (ETDEWEB)
Bryant, P M
1963-01-01
A method is given for calculating, for design purposes, the maximum permissible continuous release rates of phosphorus-32 and sulphur-35 to atmosphere with respect to milk contamination. In the absence of authoritative advice from the Medical Research Council, provisional working levels for the concentration of phosphorus-32 and sulphur-35 in milk are derived, and details are given of the agricultural assumptions involved in the calculation of the relationship between the amount of the nuclide deposited on grassland and that to be found in milk. The agricultural and meteorological conditions assumed are applicable as an annual average to England and Wales. The results (in mc/day) for phosphorus-32 and sulphur-35 for a number of stack heights and distances are shown graphically; typical values, quoted in a table, include 20 mc/day of phosphorus-32 and 30 mc/day of sulfur-35 as the maximum permissible continuous release rates with respect to ground level releases at a distance of 200 metres from pastureland.
International Nuclear Information System (INIS)
Fryer, L.S.
1978-12-01
TIRION 4 is the most recent program in a series designed to calculate the consequences of releasing radioactive material to the atmosphere. A brief description of the models used in the program and full details of the various control cards necessary to run TIRION 4 are given. (author)
International Nuclear Information System (INIS)
Kocher, D.C.
1980-01-01
Dose-rate conversion factors for external exposure to photon and electron radiation are calculated for 240 radionuclides of potential importance in routine releases from nuclear fuel cycle facilities. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each exposure mode, dose-rate conversion factors for photons and electrons are calculated for tissue-equivalent material at the body surface of an exposed individual. Dose-rate conversion factors for photons only are calculated for 22 body organs. (author)
International Nuclear Information System (INIS)
Lu, J.; Zhang, X.; Zhao, X.
2000-01-01
Relativistic discrete-variational local density functional calculations on endohedral Gd rate at C 60 , La rate at C 60 ,Gd rate at C 74 , and La rate at C 74 are performed. All the C 60 - and C 74 -derived levels are lowered upon endohedral Gd and La doping. Both the Gd (4f 7 5d 1 6s 2 ) and La (5d 1 6s 2 ) atoms only donate their two 6s valence electrons to the cages, leaving behind their 5d electrons when they are placed at the cage centers. Compared with large-band-gap C 60 , small-band-gap C 74 and Gd (La)-metallofullerenes have strong both electron-donating and electron-accepting characters, and the calculated ionization potentials and electron affinities for them agree well with the available experimental data. (orig.)
Araujo, Danilo Barral; Silva, Luciana Rodrigues; de Araujo, Roberto Paulo Correia
2010-01-01
Tooth whitening agents containing hydrogen peroxide and carbamide peroxide are used frequently in esthetic dental procedures. However, lesions on the enamel surface have been attributed to the action of these products. Using conventional procedures for separating and isolating biological structures, powdered enamel was obtained and treated with hydrogen peroxide, carbamide peroxide, and sodium bicarbonate, ingredients typically found in dentifrices. The enamel was exposed to different pH levels, and atomic emission spectrometry was used to determine calcium release rates. As the pH level increased, the rate of calcium release from enamel treated with dentifrices containing whitening agents decreased. Carbamide peroxide produced the lowest amount of decalcification, while sodium bicarbonate produced the highest release rates at all pH levels.
Influence of Strain Rate on Heat Release under Quasi-Static Stretching of Metals. Experiment
Zimin, B. A.; Sventitskaya, V. E.; Smirnov, I. V.; Sud'enkov, Yu. V.
2018-04-01
The paper presents the results of experimental studies of energy dissipation during a quasi-static stretching of metals and alloys at room temperature. The strain rates varied in the range of 10-3-10-2 s-1. Samples of M1 copper, AZ31B magnesium alloy, BT6 titanium, 12Cr18Ni10Ti steel, and D16AM aluminum alloy were analyzed. The experimental results demonstrated a significant dependence of the heat release on the strain rate in the absence of its influence on stress-strain diagrams for all the metals studied in this range of strain rates. The correlation of the changes in the character of heat release with the processes of structural transformations at various stages of plastic flow is shown on the qualitative level. A difference in the nature of the processes of heat release in materials with different ratios of the plasticity and strength is noted.
On the Impact of the Fuel Dissolution Rate Upon Near-Field Releases From Nuclear Waste Disposal
Directory of Open Access Journals (Sweden)
A Pereira
2016-09-01
Full Text Available Calculations of the impact of the dissolution of spent nuclear fuel on the release from a damaged canister in a KBS-3 repository are presented. The dissolution of the fuel matrix is a complex process and the dissolution rate is known to be one of the most important parameters in performance assessment models of the near-field of a geological repository. A variability study has been made to estimate the uncertainties associated with the process of fuel dissolution. The model considered in this work is a 3D model of a KBS-3 copper canister. The nuclide used in the calculations is Cs-135. Our results confirm that the fuel degradation rate is an important parameter, however there are considerable uncertainties associated with the data and the conceptual models. Consequently, in the interests of safety one should reduce, as far as possible, the uncertainties coupled to fuel degradation.
Rodgers, Michael J.; Wen, Shengmin; Keer, Leon M.
2000-08-01
A three-dimensional quasi-static model of faulting in an elastic half-space with a horizontal change of material properties (i.e., joined elastic quarter spaces) is considered. A boundary element method is used with a stress drop slip zone approach so that the fault surface relative displacements as well as the free surface displacements are approximated in elements over their respective domains. Stress intensity factors and free surface displacements are calculated for a variety of cases to show the phenomenological behavior of faulting in such a medium. These calculations showed that the behavior could be distinguished from a uniform half-space. Slip in a stiffer material increases, while slip in a softer material decreases the energy release rate and the free surface displacements. Also, the 1989 Kalapana earthquake was located on the basis of a series of forward searches using this method and leveling data. The located depth is 8 km, which is the closer to the seismically inferred depth than that determined from other models. Finally, the energy release rate, which can be used as a fracture criterion for fracture at this depth, is calculated to be 11.1×106 J m-2.
International Nuclear Information System (INIS)
Bangart, R.L.; Bell, L.G.; Boegli, J.S.; Burke, W.C.; Lee, J.Y.; Minns, J.L.; Stoddart, P.G.; Weller, R.A.; Collins, J.T.
1978-12-01
The calculational procedures described in the report reflect current NRC staff practice. The methods described will be used in the evaluation of applications for construction permits and operating licenses docketed after January 1, 1979, until this NUREG is revised as a result of additional staff review. The BWR-GALE (Boiling Water Reactor Gaseous and Liquid Effluents) Code is a computerized mathematical model for calculating the release of radioactive material in gaseous and liquid effluents from boiling water reactors (BWRs). The calculations are based on data generated from operating reactors, field tests, laboratory tests, and plant-specific design considerations incorporated to reduce the quantity of radioactive materials that may be released to the environment
40 CFR 75.83 - Calculation of Hg mass emissions and heat input rate.
2010-07-01
... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Calculation of Hg mass emissions and... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Hg Mass Emission Provisions § 75.83 Calculation of Hg mass emissions and heat input rate. The owner or operator shall calculate Hg mass emissions...
Calculation of radiation dose rate arisen from radionuclide contained in building materials
International Nuclear Information System (INIS)
Lai Tien Thinh; Nguyen Hao Quang
2008-01-01
This paper presents some results that we used MCNP5 program to calculate radiation dose rate arisen from radionuclide in building materials. Since then, the limits of radionuclide content in building materials are discussed. The calculation results by MCNP are compared with those calculated by analytical method. (author)
Energy Technology Data Exchange (ETDEWEB)
Oversby, V.M. (ed.) [and others
2003-10-01
the system that will not be present under long term disposal conditions. A simulation of long-term conditions can be done using uranium dioxide that contains a short-lived isotope of uranium, but this will not include the effects of fission product and higher actinide elements on the behaviour of the spent fuel. We designed a project that had as its objective to improve the scientific understanding of the processes that control release of radioactive species from spent fuel inside a disposal canister and the chemical changes in those species that might limit release of radioactivity from the canister. If the mechanisms that control dissolution of the fuel matrix, including self-irradiation effects, can be clarified, a more realistic assessment of the long-term behaviour of spent fuel under disposal conditions can be made. By removing uncertainties concerning waste form performance, a better assessment of the individual and collective role of the engineered barriers can be made. To achieve the overall objective of the project, the following scientific and technical objectives were set. 1. Measure the actual rate of matrix dissolution of uranium dioxide under oxidising and reducing conditions. 2. Measure the effect of alpha radiolysis on the dissolution rate of uranium dioxide under oxidising and reducing conditions. 3. Measure the dissolution rate of the matrix material of spent fuel and thereby determine the additional effects of beta and gamma radiation on uranium dioxide dissolution rate under oxidising and reducing conditions. 4. Measure the ability of actively corroding iron to reduce oxidised U(VI) to U(IV) when U is present as the complex ion uranyl carbonate. 5. Measure the rate of reduction of Np(V) species in the presence of actively corroding iron. 6. Calculate the expected equilibrium and steady state concentrations of U under the conditions of the experiments used for meeting objectives 1 through 3 and compare the calculated results with those measured in
The calculation of coolant leak rate through the cracks using RELAP5 code
International Nuclear Information System (INIS)
Krungeleviciute, V.; Kaliatka, A.
2001-01-01
For reason to choose method of leak detection first of all it is necessary to perform evaluating thermal-hydraulic calculations. These calculations allow to determine flow rate of discharged coolant. For coolant leak rate calculations through possible cracks in Ignalina NPP pipes SQUIRT and RELAP5 thermal-hydraulic codes were used. SQUIRT is well known as computer program that predicts the leakage for cracked pipes in NPP. As this code calculates only water (at subcooled or saturated conditions) leak rate, RELAP5 code model, that calculates water and steam leak rate, was created. For model validation comparison of SQUIRT, RELAP5 and experimental results was performed. Analysis shows RELAP5 code model suitability for calculations of leak through through-wall cracks in pipes. (author)
Calculation methods for dissolution rate of multicomponent alloys during electrochemical machining
International Nuclear Information System (INIS)
Dikusar, A.I.; Petrenko, V.I.; Dikusar, G.K.; Ehngel'gardt, G.R.; Michukova, N.Yu.
1981-01-01
The possibility of theoretical calculation of metal dissolution rate during electrochemical mashining is considered. Two calculation techniques are compared at the example of two-component W-Re, Ni-W, Mo-Re alloys, namely: ''charge superposition'' and ''weight percents''. It is concluded that the technique of ''charge superposition'' is the only grounded calculation technique of specific rates of dissolution for alloys [ru
Tritium breeding and release-rate kinetics from neutron-irradiated lithium oxide
International Nuclear Information System (INIS)
Quanci, J.F.
1989-01-01
The research encompasses the measurement of the tritium breeding and release-rate kinetics from lithium oxide, a ceramic tritium-breeding material. A thermal extraction apparatus which allows the accurate measurement of the total tritium inventory and release rate from lithium oxide samples under different temperatures, pressures and carrier-gas compositions with an uncertainty not exceeding 3% was developed. The goal of the Lithium Blanket Module program was to determine if advanced computer codes could accurately predict the tritium production in the lithium oxide blanket of a fusion power plant. A fusion blanket module prototype, was built and irradiated with a deuterium-tritium fusion-neutron source. The tritium production throughout the module was modeled with the MCNP three dimensional Monte Carlo code and was compared to the assay of the tritium bred in the module. The MCNP code accurately predicted tritium-breeding trends but underestimated the overall tritium breeding by 30%. The release rate of tritium from small grain polycrystalline sintered lithium oxide with a helium carrier gas from 300 to 450 C was found to be controlled by the first order surface desorption of mono-tritiated water. When small amounts of hydrogen were added to the helium carrier gas, the first order rate constant increased from the isotopic exchange of hydrogen for tritium at the lithium oxide surface occurring in parallel with the first order desorption process. The isotopic-exchange first order rate constant temperature dependence and hydrogen partial pressure dependence were evaluated. Large single crystals of lithium oxide were fabricated by the vacuum fusion technique. The release rate of tritium from the large single crystals was found to be controlled by diffusion, and the mixed diffusion-desorption controlled release regime
Research on release rate of volatile organic compounds in typical vessel cabin
Directory of Open Access Journals (Sweden)
ZHANG Jinlan
2018-02-01
Full Text Available [Objectives] Volatile Organic Compounds (VOC should be efficiently controlled in vessel cabins to ensure the crew's health and navigation safety. As an important parameter, research on release rate of VOCs in cabins is required. [Methods] This paper develops a method to investigate this parameter of a ship's cabin based on methods used in other closed indoor environments. A typical vessel cabin is sampled with Tenax TA tubes and analyzed by Automated Thermal Desorption-Gas Chromatography-Mass Spectrometry (ATD-GC/MS. The lumped mode is used and the release rate of Benzene, Toluene, Ethylbenzene and Xylene (BTEX, the typical representatives of VOCs, is obtained both in closed and ventilated conditions. [Results] The results show that the content of xylene and Total Volatile Organic Compounds (TVOC exceed the indoor environment standards in ventilated conditions. The BTEX release rate is similar in both conditions except for the benzene. [Conclusions] This research builds a method to measure the release rate of VOCs, providing references for pollution character evaluation and ventilation and purification system design.
Salm, van der C.; Westerveld, J.W.; Verstraten, J.M.
2000-01-01
Research with respect to release rates of Al and Al concentrations in the soil solution has led to two contrasting hypotheses, stressing either the importance of kinetically constrained dissolution reactions or the role of complexation of Al to soil organic matter. The existence of two contrasting
On the energy release rate in a turbulent current sheet on the Sun
International Nuclear Information System (INIS)
Bardakov, V.M.
1986-01-01
It is shown that turbulent current sheets on the Sun, realizing in the form of the Parker - Sweet flow, are in quasilinear regime of turbulence (or in the regime of instability threshold). The energy release rate in such sheets does not exceed 10 26 erg/s for typical plasma parameters in active regions
Release modes and processes relevant to source-term calculations at Yucca Mountain
International Nuclear Information System (INIS)
Apted, M.J.
1994-01-01
The feasibility of permanent disposal of radioactive high-level waste (HLW) in repositories located in deep geologic formations is being studied world-wide. The most credible release pathway is interaction between groundwater and nuclear waste forms, followed by migration of radionuclide-bearing groundwater to the accessible environment. Under hydrologically unsaturated conditions, vapor transport of volatile radionuclides is also possible. The near-field encompasses the waste packages composed of engineered barriers (e.g. man-made materials, such as vitrified waste forms, corrosion-resistant containers), while the far-field includes the natural barriers (e.g. host rock, hydrologic setting). Taken together, these two subsystems define a series of multiple, redundant barriers that act to assure the safe isolation of nuclear waste. In the U.S., the Department of energy (DOE) is investigating the feasibility of safe, long-term disposal of high-level nuclear waste at the Yucca Mountain site in Nevada. The proposed repository horizon is located in non-welded tuffs within the unsaturated zone (i.e. above the water table) at Yucca Mountain. The purpose of this paper is to describe the source-term models for radionuclide release from waste packages at Yucca Mountain site. The first section describes the conceptual release modes that are relevant for this site and waste package design, based on a consideration of the performance of currently proposed engineered barriers under expected and unexpected conditions. No attempt is made to asses the reasonableness nor probability of occurrence for any specific release mode. The following section reviews the waste-form characteristics that are required to model and constrain the release of radionuclides from the waste package. The next section present mathematical models for the conceptual release modes, selected from those that have been implemented into a probabilistic total system assessment code developed for the Electric Power
International Nuclear Information System (INIS)
Lee, J.H.; Atkins, J.E.; McNeish, J.A.; Vallikat, V.
1996-01-01
The first model assumed that dripping water directly contacts the waste form inside the ''failed'' waste package and radionuclides are released from the EBS by advection. The second model assumed that dripping water is diverted around the package (because of corrosion products plugging the perforations), thereby being prevented from directly contacting the waste form. In the second model, radionuclides were assumed to diffuse through the perforations, and, once outside the waste package, to be released from the EBS by advection. For the case with the second EBS release model, most radionuclides had lower peak EBS release rates than with the first model. Impacts of the alternative EBS release models were greater for the radionuclides with low solubility. The analysis indicated that the EBS release model representing advection through a ''failed'' waste package (the first model) may be too conservative; thus a ''failed'' waste package container with multiple perforations may still be an important barrier to radionuclide release
Audit Calculations of LBLOCA for Ulchin Unit 1 and 2 Power Up rate
Energy Technology Data Exchange (ETDEWEB)
Kang, Donggu; Huh, Byunggil; Yoo, Seunghunl; Yang, Chaeyong; Seul, Kwangwon [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)
2013-05-15
The KINS-Realistic Evaluation Model (KINS-REM) was developed for the independent audit calculation in 1991, and the code accuracy and statistical method have been improved. To support the licensing review and to confirm the validity of licensee's calculation, regulatory auditing calculations have been also conducted. Currently, the modification of Ulchin 1 and 2 operating license for 4.5% power up rate is under review. In this study, the regulatory audit calculation for LBLOCA of Ulchin Unit 1 and 2 with 4.5% power up rate was performed by applying KINS-REM. In this study, the regulatory audit calculation for LBLOCA of Ulchin Unit 1 and 2 with 4.5% power up rate was performed by applying KINS-REM. It is confirmed that the analysis results of LBLOCA for Ulchin 1 and 2 power up rate meets the PCT acceptance criteria.
Sakamoto, Y
2002-01-01
In the prevention of nuclear disaster, there needs the information on the dose equivalent rate distribution inside and outside the site, and energy spectra. The three dimensional radiation transport calculation code is a useful tool for the site specific detailed analysis with the consideration of facility structures. It is important in the prediction of individual doses in the future countermeasure that the reliability of the evaluation methods of dose equivalent rate distribution and energy spectra by using of Monte Carlo radiation transport calculation code, and the factors which influence the dose equivalent rate distribution outside the site are confirmed. The reliability of radiation transport calculation code and the influence factors of dose equivalent rate distribution were examined through the analyses of critical accident at JCO's uranium processing plant occurred on September 30, 1999. The radiation transport calculations including the burn-up calculations were done by using of the structural info...
Use of ELOCA.Mk5 to calculate transient fission product release from CANDU fuel elements
International Nuclear Information System (INIS)
Walker, J.R.; de Vaal, J.W.; Arimescu, V.I.; McGrady, T.G.; Wong, C.
1992-04-01
A change in fuel element power output, or a change in heat transfer conditions, will result in an immediate change in the temperature distribution in a fuel element. The temperature distribution change will be accompanied by concomitant changes in fuel stress distribution that lead, in turn, to a release of fission products to the fuel-to-sheath gap. It is important to know the inventory of fission products in the fuel-to-sheath gap, because this inventory is a major component of the source term for many postulated reactor accidents. ELOCA.Mk5 is a FORTRAN-77 computer code that has been developed to estimate transient releases to the fuel-to-sheath gap in CANDU reactors. ELOCA.Mk5 is an integration of the FREEDOM fission product release model into the ELOCA fuel element thermo-mechanical code. The integration of FREEDOM into ELOCA allows ELOCA.Mk5 to model the feedback mechanisms between the fission product release and the thermo-mechanical response of the fuel element. This paper describes the physical model, gives details of the ELOCA.Mkt code, and describes the validation of the model. We demonstrate that the model gives good agreement with experimental results for both steady state and transient conditions
Groundwater flow analysis and dose rate estimates from releases to wells at a coastal site
Energy Technology Data Exchange (ETDEWEB)
Kattilakoski, E.; Suolanen, V. [VTT Energy, Espoo (Finland)
2000-09-01
{sup 3}/a. Due to the placing of the shallow wells in the discharge areas, the dilution calculated in the shallow well was shown to be close to that calculated in the deep well. In conservative considerations the value around 90 000 m{sup 3}/a can be regarded as a representative expectation value of the effective dilution of the well. This dilution volume value was also suggested by the most realistic modelling approach of the groundwater flow analysis. It was used as basis when calculating the nuclide specific dose conversion factors (DCF's) for the drinking water pathway. The DCF's were calculated for unit release rates (1 Bq/a) and the assumed water consumption rate was 2 litres/day. (orig.)
A compartment model for nuclide release calculation in the near-and far-field of a HLW repository
International Nuclear Information System (INIS)
Lee, Youn Myoung; Hwang, Yong Soo; Kang, Chul Hyung; Hahn, Pil Soo
2004-01-01
The HLW-relevant R and D program for disposal of high-level radioactive waste has been carried out at Korea Atomic Energy Research Institute (KAERI) since early 1997, from which a conceptual Korea Reference Repository System for direct disposal of nuclear spent fuel is to be introduced by the end of 2007. A preliminary reference geologic repository concept considering such established criteria and requirements as spent fuel and generic site characteristics in Korea was roughly envisaged in 2003. Not only to demonstrate how much a reference repository is safe in the generic point of view with several possible scenarios and cases associated with a preliminary repository concept by conducting calculations for nuclide release and transport in the near - and far - field components of the repository, even though sufficient information has not been available that much yet, but also to show a appropriate methodology by which both a generic and site - specific safety assessment could be performed for further in - depth development of Korea reference repository concept, nuclide release calculation study for various nuclide release cases is mandatory. To this end a similar study done and yet limited for the near - field release case has been extended to the case including far - field system by introducing some more geosphere compartments. Advective and longitudinal dispersive nuclide transports along the fracture with matrix diffusion as well as several retention mechanisms and nuclide ingrowth has been added
Phenazopyridine-phthalimide nano-cocrystal: Release rate and oral bioavailability enhancement.
Huang, Yu; Li, Jin-Mei; Lai, Zhi-Hui; Wu, Jun; Lu, Tong-Bu; Chen, Jia-Mei
2017-11-15
Both cocrystal and nanocrystal technologies have been widely used in the pharmaceutical development for poorly soluble drugs. However, the synergistic effects due to the integration of these two technologies have not been well investigated. The aim of this study is to develop a nano-sized cocrystal of phenazopyridine (PAP) with phthalimide (PI) to enhance the release rate and oral bioavailability of PAP. A PAP-PI nano-cocrystal with particle diameter of 21.4±0.1nm was successfully prepared via a sonochemical approach and characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis. An in vitro release study revealed a significant release rate enhancement for PAP-PI nano-cocrystal as compared to PAP-PI cocrystal and PAP hydrochloride salt. Further, a comparative oral bioavailability study in rats indicated significant improvement in C max and oral bioavailability (AUC 0-∞ ) by 1.39- and 2.44-fold, respectively. This study demonstrated that this novel nano-cocrystal technology can be a new promising option to improve release rate and absorption of poorly soluble compounds in the pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Rezaeian Mahdi
2015-01-01
Full Text Available Containment of a transport cask during both normal and accident conditions is important to the health and safety of the public and of the operators. Based on IAEA regulations, releasable activity and maximum permissible volumetric leakage rate within the cask containing fuel samples of Tehran Research Reactor enclosed in an irradiated capsule are calculated. The contributions to the total activity from the four sources of gas, volatile, fines, and corrosion products are treated separately. These calculations are necessary to identify an appropriate leak test that must be performed on the cask and the results can be utilized as the source term for dose evaluation in the safety assessment of the cask.
Energy Technology Data Exchange (ETDEWEB)
Rillard, J. [Earth Sciences Department UMR CNRS 5276 University of Lyon 1, Villeurbanne (France); INERIS French National Institut of Environmental and Industrial Risk Survey, Underground Risk Division,, Verneuil en Hallate (France); Gombert, P.; Toulhoat, P. [INERIS French National Institut of Environmental and Industrial Risk Survey, Underground Risk Division,, Verneuil en Hallate (France); Zuddas, P. [Earth Sciences Department UMR CNRS 5276 University of Lyon 1, Villeurbanne (France); University Pierre and Marie Curie Paris-Sorbonne, ISTEP, Paris (France)
2013-07-01
We performed an injection of CO{sub 2}-saturated water in a shallow aquifer following a 'push-pull' test protocol. A specific protocol was designed to measure in situ fluid pH and redox potential with careful sampling. We found increases of dissolved calcium, magnesium, alkalinity, iron and manganese, and other trace elements. Concentrations of Fe resulting from reactivity were estimated using measured concentrations of Fe corrected by a calculated fluid dynamics coefficient. Thermodynamic equilibrium calculations suggested that ferri-hydrite Fe(OH){sub 3} dissolution is the main source of iron release. The kinetic rate of Fe(OH){sub 3} dissolution estimated by a surface protonation model indicates that the reaction order is two. Since laboratory experimental results show a reaction order of zero, we propose that the mechanism of ferri-hydrite dissolution proceeds by a more complex mechanism under natural conditions. (authors)
Tritium breeding and release-rate kinetics from neutron-irradiated lithium oxide
International Nuclear Information System (INIS)
Quanci, J.F.
1989-01-01
The research encompasses the measurement of the tritium breeding and release-rate kinetics from lithium oxide, a ceramic tritium-breeding material. A thermal extraction apparatus which allows the accurate measurement of the total tritium inventory and release rate from lithium oxide samples under different temperatures, pressures and carrier-gas compositions with an uncertainty not exceeding 3% was developed. The goal of the Lithium Blanket Module program was to determine if advanced computer codes could accurately predict the tritium production in the lithium oxide blanket of a fusion power plant. A fusion blanket module prototype was built and irradiated with a deuterium-tritium fusion-neutron source. The tritium production throughout the module was modeled with the MCNP three dimensional Monte Carlo code and was compared to the assay of the tritium bred in the module. The MCNP code accurately predicted tritium-breeding trends but underestimated the overall tritium breeding by 30%. The release rate of tritium from small grain polycrystalline sintered lithium oxides with a helium carrier gas from 300 to 450 C was found to be controlled by the first order surface desorption of monotritiated water. When small amounts of hydrogen were added to the helium carrier gas, the first order rate constant increased from the isotopic exchange of hydrogen for tritium at the lithium oxide surface occurring in parallel with the first order desorption process. The isotopic-exchange first order rate constant temperature dependence and hydrogen partial pressure dependence were evaluated
FABGEN, a transient power-generation and isotope birth rate calculator
International Nuclear Information System (INIS)
Roland, H.C.
1975-04-01
A description is given of the FABGEN program, a fast-running program for calculating fuel element power-generation rates and selected fission product birth rates in a known neutron flux as functions of time. A first forward difference calculation is used, and the time step is one day. Provisions are made for including various fuel element lengths, variation of thermal flux with time, and use of different fertile isotopes. Five different fission products may be specified for birth-rate calculations. A daily summary may be output, or totals by days may be accumulated for final output. (U.S.)
Energy Technology Data Exchange (ETDEWEB)
El-Maaref, A.A., E-mail: ahmed.maaref@azhar.edu.eg; Saddeek, Y.B.; Abou halaka, M.M.
2017-02-15
Highlights: • Fine-structure calculations of sulfurlike Mn have been performed using configuration interaction technique, CI. • The relativistic effects, Breit-Pauli Hameltonian, have been correlated to the CI calculations. • Excitation rates by electron impact of the Mn X ion have been evaluated up to ionization potential. - Abstract: Fine-structure calculations of energies and transition parameters have been performed using the configuration interaction technique (CI) as implemented in CIV3 code for sulfurlike manganese, Mn X. The calculations are executed in an intermediate coupling scheme using the Breit-Pauli Hamiltonian. As well as, energy levels and oscillator strengths are calculated using LANL code, where the calculations by LANL have been used to estimate the accuracy of the present CI calculations. The calculated energy levels, oscillator strengths, and lifetimes are in reasonable agreement with the published experimental and theoretical values. Electron impact excitation rates of the transitions emit soft X-ray and extreme ultraviolet (EUV) wavelengths have been evaluated. The level population densities are calculated using the collisional radiative model (CRM), as well. The collisional excitation rates and collision strengths have been calculated in the electron temperature range ≤ the ionization potential, ∼1–250 eV.
2011-04-12
... consistently the term ``regular hours.'' The term ``regular hours'' refers to the hours during regular working... during non-overtime and non-holiday hours of operation. Official establishments and official egg products.... FSIS developed proposed formulas in consultation with a private accounting firm to determine the rates...
LOFC fission product release and circulating activity calculations for gas-cooled reactors
International Nuclear Information System (INIS)
Apperson, C.E. Jr.; Carruthers, L.M.; Lee, C.E.
1977-01-01
The inventories of fission products in a gas-cooled reactor under accident and normal steady state conditions are time and temperature dependent. To obtain a reasonable estimate of these inventories it is necessary to consider fuel failure, a temperature dependent variable, and radioactive decay, a time dependent variable. Using arbitrary radioactive decay chains and published fuel failure models for the High Temperature Gas-Cooled Reactor (HTGR), methods have been developed to evaluate the release of fission products during the Loss of Forced Circulation (LOFC) accident and the circulating and plateout fission product inventories during steady state non-accident operation. The LARC-2 model presented here neglects the time delays in the release from the HTGR due to diffusion of fission products from particles in the fuel rod through the graphite matrix. It also neglects the adsorption and evaporation process of metallics at the fuel rod-graphite and graphite-coolant hole interfaces. Any time delay due to the finite time of transport of fission products by convection through the coolant to the outside of the prestressed concrete reactor vessel (PCRV) is also neglected. This model assumes that all fission products released from fuel particles are immediately deposited outside the PCRV with no time delay
Relativistic quasiparticle random-phase approximation calculation of total muon capture rates
International Nuclear Information System (INIS)
Marketin, T.; Paar, N.; Niksic, T.; Vretenar, D.
2009-01-01
The relativistic proton-neutron quasiparticle random phase approximation (pn-RQRPA) is applied in the calculation of total muon capture rates on a large set of nuclei from 12 C to 244 Pu, for which experimental values are available. The microscopic theoretical framework is based on the relativistic Hartree-Bogoliubov (RHB) model for the nuclear ground state, and transitions to excited states are calculated using the pn-RQRPA. The calculation is fully consistent, i.e., the same interactions are used both in the RHB equations that determine the quasiparticle basis, and in the matrix equations of the pn-RQRPA. The calculated capture rates are sensitive to the in-medium quenching of the axial-vector coupling constant. By reducing this constant from its free-nucleon value g A =1.262 by 10% for all multipole transitions, the calculation reproduces the experimental muon capture rates to better than 10% accuracy.
Energy Technology Data Exchange (ETDEWEB)
Shapiro, A; Lin, B I [Cincinnati Univ., Ohio (USA). Dept. of Chemical and Nuclear Engineering; Windham, J P; Kereiakes, J G
1976-07-01
..gamma.. flux density and dose rate distributions have been calculated about implantable californium-252 sources for an infinite tissue medium. Point source flux densities as a function of energy and position were obtained from a discrete-ordinates calculation, and the flux densities were multiplied by their corresponding kerma factors and added to obtain point source dose rates. The point dose rates were integrated over the line source to obtain line dose rates. Container attenuation was accounted for by evaluating the point dose rate as a function of platinum thickness. Both primary and secondary flux densities and dose rates are presented. The agreement with an independent Monte Carlo calculation was excellent. The data presented should be useful for the design of new source configurations.
DEFF Research Database (Denmark)
Ørtenblad, Niels; Sjøgaard, G; Madsen, Klavs
2000-01-01
during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P ... to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which......The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate...
Modeling for Dose Rate Calculation of the External Exposure to Gamma Emitters in Soil
International Nuclear Information System (INIS)
Allam, K. A.; El-Mongy, S. A.; El-Tahawy, M. S.; Mohsen, M. A.
2004-01-01
Based on the model proposed and developed in Ph.D thesis of the first author of this work, the dose rate conversion factors (absorbed dose rate in air per specific activity of soil in nGy.hr - 1 per Bq.kg - 1) are calculated 1 m above the ground for photon emitters of natural radionuclides uniformly distributed in the soil. This new and simple dose rate calculation software was used for calculation of the dose rate in air 1 m above the ground. Then the results were compared with those obtained by five different groups. Although the developed model is extremely simple, the obtained results of calculations, based on this model, show excellent agreement with those obtained by the above-mentioned models specially that one adopted by UNSCEAR. (authors)
Distorted wave approach to calculate Auger transition rates of ions in metals
Energy Technology Data Exchange (ETDEWEB)
Deutscher, Stefan A. E-mail: sad@utk.edu; Diez Muino, R.; Arnau, A.; Salin, A.; Zaremba, E
2001-08-01
We evaluate the role of target distortion in the determination of Auger transition rates for multicharged ions in metals. The required two electron matrix elements are calculated using numerical solutions of the Kohn-Sham equations for both the bound and continuum states. Comparisons with calculations performed using plane waves and hydrogenic orbitals are presented.
International Nuclear Information System (INIS)
Quade, U.
1994-01-01
Neutron- und Gamma dose rate calculations were performed for the storage containers filled with plutonium nitrate of the MOX fabrication facility of Siemens. For the particle transport calculations the Monte Carlo Code MCNP 4.2 was used. The calculated results were compared with experimental dose rate measurements. It can be stated that the choice of the code system was appropriate since all aspects of the many facettes of the problem were well reproduced in the calculations. The position dependency as well as the influence of the shieldings, the reflections and the mutual influences of the sources were well described by the calculations for the gamma and for the neutron dose rates. However, good agreement with the experimental results on the gamma dose rates could only be reached when the lead shielding of the detector was integrated into the geometry modelling of the calculations. For some few cases of thick shieldings and soft gamma ray sources the statistics of the calculational results were not sufficient. In such cases more elaborate variance reduction methods must be applied in future calculations. Thus the MCNP code in connection with NGSRC has been proven as an effective tool for the solution of this type of problems. (orig./HP) [de
A modified Gaussian integration method for thermal reaction rate calculation in U- and Pu-isotopes
International Nuclear Information System (INIS)
Bosevski, T.; Fredin, B.
1966-01-01
An advanced multi-group cell calculations a lot of data information is very often necessary, and hence the data administration will be elaborate, and the spectrum calculation will be time consuming. We think it is possible to reduce the necessary data information by using an effective reaction rate integration method well suited for U- and Pu-absorptions (author)
THIDA: code system for calculation of the exposure dose rate around a fusion device
International Nuclear Information System (INIS)
Iida, Hiromasa; Igarashi, Masahito.
1978-12-01
A code system THIDA has been developed for calculation of the exposure dose rates around a fusion device. It consists of the following: one- and two-dimensional discrete ordinate transport codes; induced activity calculation code; activation chain, activation cross section, radionuclide gamma-ray energy/intensity and gamma-ray group constant files; and gamma ray flux to exposure dose rate conversion coefficients. (author)
The correlation schemes in calculations of the rate constants of some radiation chemical reactions
International Nuclear Information System (INIS)
Zagorets, P.A.; Shostenko, A.G.; Kim, V.
1983-01-01
The various correlation relationships of the evaluation of the rate constants of radiation chemical reactions of addition, abstraction and isomerization were considered. It was shown that neglection of the influence of solvent can result in errors in calculations of rate constants equalling two orders in magnitude. Several examples of isokinetic relationship are given. The methods of calculation of transmission coefficient of reaction addition have been discussed. (author)
Comparison of numerical models for calculating dispersion from accidental releases of pollutants
Energy Technology Data Exchange (ETDEWEB)
Pepper, D W [Savannah River Lab., Aiken, SC; Cooper, R E; Baker, A J
1982-01-01
A modular, data-based system approach has been developed to facilitate computational simulation of multi-dimensional pollutant dispersion in atmospheric, steam, estuary, and groundwater applications. This system is used to assess effects of accidental releases of pollutants to the environment. Model sophistication ranges from simple statistical to complex three-dimensional numerical methods. The system used specifies desired degree of model sophistication from a terminal. The model used depends on the particular type of problem being solved, and on a basis of merit related to computer cost. The results of prediction for several model problems are presented.
Radionuclide release calculations for selected severe accident scenarios. PWR, ice condenser design
Energy Technology Data Exchange (ETDEWEB)
Denning, R S; Gieseke, J A; Cybulskis, P; Lee, K W; Jordan, H; Curtis, L A; Kelly, R F; Kogan, V; Schumacher, P M
1986-07-01
This report presents results of analyses of the environmental releases of fission products (source terms) for severe accident scenarios in a pressurized water reactor with an ice-condenser containment. The analyses were performed to support the Severe Accident Risk Reduction/Risk Rebaselining Program (SARRP) which is being undertaken for the U.S. Nuclear Regulatory Commission by Sandia National Laboratories. In the SARRP program, risk estimates are being generated for a number of reference plant designs. The Sequoyah Plant has been used in this study as an example of a PWR ice-condenser plant. (author)
International Nuclear Information System (INIS)
Denning, R.S.; Gieseke, J.A.; Cybulskis, P.; Lee, K.W.; Jordan, H.; Curtis, L.A.; Kelly, R.F.; Kogan, V.; Schumacher, P.M.
1986-07-01
This report presents results of analyses of the enviromental releases of fission products (source terms) for severe accident scenarios in a pressurized water reactor with a subatmospheric containment design. The analyses were performed to support the Severe Accident Risk Reduction/Risk Rebaselining Program (SARRP) which is being undertaken for the US Nuclear Regulatory Commission by Sandia National Laboratories. In the SARRP program, risk estimates are being generated for a number of reference plant designs. the Surry plant has been used in this study as the reference plant for a subatmospheric design
Recent research on stishovite: Hugoniot and partial release Z experiments and DFT EOS calculations.
Energy Technology Data Exchange (ETDEWEB)
Furnish, Michael D.; Shulenburger, Luke; Desjarlais, Michael; Fei, Yingwei
2018-04-01
We have conducted a series of ride-along experiments on the Z facility to ascertain the Hugoniot of silica centered in the stishovite phase over a range 0.4 - 1.0 TPa, together with partial release states produced at the interface between the sample and a fused silica window. The stishovite samples were synthesized in a large-volume multi-anvil press at 15 GPa and 1773 K, with an initial density of 4.29 gm/cc. The new Z experiments on stishovite fill in a gap between gas gun experiments and NIF experiments. The states are compared with the Hugoniots of quartz and fused silica for inferences as to EOS. They are generally consistent with Sesame 7360 predictions. Sound speed constraints from these data are discussed. The new Hugoniot data cross over the melting curve of stishovite; together with the partial-release data and predictions from density-functional theory modeling, they provide insights into the properties of solid and liquid under extreme conditions. These data are fundamentally important for understanding the interior of silicate-based super-Earths.
A calculation of the surface recombination rate constant for hydrogen isotopes on metals
International Nuclear Information System (INIS)
Baskes, M.J.
1980-01-01
The surface recombination rate constant for hydrogen isotopes on a metal has been calculated using a simple model whose parameters may be determined by direct experimental measurements. Using the experimental values for hydrogen diffusivity, solubility, and sticking coefficient at zero surface coverage a reasonable prediction of the surface recombination constant may be made. The calculated recombination constant is in excellent agreement with experiment for bcc iron. A heuristic argument is developed which, along with the rate constant calculation, shows that surface recombination is important in those metals in which hydrogen has an exothermic heat of solution. (orig.)
International Nuclear Information System (INIS)
Sunder, S.; Shoesmith, D.W.; Kolar, M.; Leneveu, D.M.
1998-01-01
Calculation of used nuclear fuel dissolution rates in a geological disposal vault requires a knowledge of the redox conditions in the vault. For redox conditions less oxidizing than those causing UO 2 oxidation to the U 3 O 7 , stage, a thermodynamically-based model is appropriate. For more oxidizing redox conditions a kinetic or an electrochemical model is needed to calculate these rates. The redox conditions in a disposal vault will be affected by the radiolysis of groundwater by the ionizing radiation associated with the fuel. Therefore, we have calculated the alpha-, beta- and gamma-dose rates in water in contact with the reference used fuel in the Canadian Nuclear Fuel Waste Management Program (CNFWMP) as a function of cooling time. Also, we have determined dissolution rates of UO 2 fuel as a function of alpha and gamma dose rates from our electrochemical measurements. These room-temperature rates are used to calculate the dissolution rates of used fuel at 100 o C, the highest temperature expected in a container in the CNFWMP, as a function of time since emplacement. It is shown that beta radiolysis of water will be the main cause of oxidation of used CANDU fuel in a failed container. The use of a kinetic or an electrochemical corrosion model, to calculate fuel dissolution rates, is required for a period of ∼1000 a following emplacement of copper containers in the geologic disposal vault envisaged in the CNFWMP. Beyond this time period a thermodynamically-based model adequately predicts the fuel dissolution rates. The results presented in this paper can be adopted to calculate used fuel dissolution rates for other used UO 2 fuels in other waste management programs. (author)
Calculation of nuclide inventory, decay power, activity and dose rates for spent nuclear fuel
International Nuclear Information System (INIS)
Haakansson, Rune
2000-03-01
The nuclide inventory was calculated for a BWR and a PWR fuel element, with burnups of 38 and 55 MWd/kg uranium for the BWR fuel, and 42 and 60 MWd/kg uranium for the PWR fuel. The calculations were performed for decay times of up to 300,000 years. Gamma and neutron dose rates have been calculated at a distance of 1 m from a bare fuel element and outside the spent fuel canister. The calculations were performed using the CASMO-4 code
HLW disposal by fission reactors; calculation of trans-mutation rate and recycle
International Nuclear Information System (INIS)
Mulyanto
1997-01-01
Transmutation of MA (Minor actinide) and LLFPS (long-lived fission products) into stable nuclide or short-lived isotopes by fission reactors seem to become an alternative technology for HLW disposal. in this study, transmutation rate and recycle calculation were developed in order to evaluate transmutation characteristics of MA and LLFPs in the fission reactors. inventory of MA and LLFPs in the transmutation reactors were determined by solving of criticality equation with 1-D cylindrical geometry of multigroup diffusion equations at the beginning of cycle (BOC). transmutation rate and burn-up was determined by solving of depletion equation. inventory of MA and LLFPs was calculated for 40 years recycle. From this study, it was concluded that characteristics of MA and LLFPs in the transmutation reactors can be evaluated by recycle calculation. by calculation of transmutation rate, performance of fission reactor for transmutation of MA or LLFPs can be discussed
Methodology for calculating radiation doses from radioactivity released to the environment
International Nuclear Information System (INIS)
Killough, G.G.; McKay, L.R.
1976-03-01
This document represents a compilation of the principal environmental transport and dosimetry models developed, adapted, and implemented by the Radiological Analyses and Applications Group of the Environmental Sciences Division of the Oak Ridge National Laboratory. The transport of released radioactivity through the natural environment is discussed in four sections: atmospheric dispersion, resuspension of material by wind action, terrestrial transport, and movement of material in underground water seepage. The discussion of dose to man and biota is divided into internal and external exposure sections. And finally, a developmental model (CONDOS) which estimates the dose to a population resulting from the manufacture, storage, distribution, use, and disposal of consumer products which contain radioactivity is described. Numerous tables are included
International Nuclear Information System (INIS)
Ponting, A.C.; Nair, S.
1984-04-01
A concept extensively used in studying the consequences of accidental atmospheric radioactive releases is that of the Complementary Cumulative Distribution Function, CCDF. Various methods of calculating CCDFs have been developed with particular applications in putting degraded core accidents in perspective and in identifying release sequences leading to high risks. This note compares three methods with specific reference to their accuracy and computational efficiency. For two of the methods (that used in the US Reactor Safety Study code CRAC2 and extended version of that method), the effects of varying the sector width and considering site-specific population distributions have been determined. For the third method it is only necessary to consider the effects of site-specific population distributions. (author)
Shah, Shefaatullah; Khan, Gul Majid; Jan, Syed Umer; Shah, Kifayatullah; Hussain, Abid; Khan, Haroon; Khan, Haroon; Khan, Haroon; Khan, Kamran Ahmad
2012-01-01
The aim of the present study was the formulation and evaluation of controlled release polymeric tablets of Diclofenac Potassium by wet granulation method for the release rate, release pattern and the mechanism involved in drug release. Formulations having three grades of polymer Ethocel (7P; 7FP, 10P, 10FP, 100P, 100FP) in several drugs to polymer ratios (10:3 and 10:1) were compressed into tablets using wet granulation method. Co-excipients were added to some selected formulations to investigate their enhancement effect on in vitro drug release patterns. In vitro drug release studies were performed using USP Method-1 (Rotating Basket method) and Phosphate buffer (pH 7.4) was used as a dissolution medium. The similarities and dissimilarities of release profiles of test formulations with reference standard were checked using f2 similarity factor and f1 dissimilarity factor. Mathematical/Kinetic models were employed to determine the release mechanism and drug release kinetics.
Preliminary calculations on the cooling rate of the Renca batholit, Sierra de San Luis, Argentina
International Nuclear Information System (INIS)
Lopez de Luchi, M.G.; Ostera, H.A.; Linares, E; Rosello, E.A
2001-01-01
Cooling rates can be used to constrain the unroofing history of plutonic-metamorphic system. Geocronological cooling rates (Spear and Parrish, 1996) can be unravelled using age calculations on minerals that were open systems and subsequently passed through their closure temperatures (Dodson, 1973) during cooling. Several age determinations on different minerals are needed in order to accurately constrain the cooling path of a pluton (Hodges 1991, Spear and Parrish, 1996 and references therein). Isotopic open-system behaviour in minerals can be modelled as volume diffusion process (Hodges, 1991 and references therein), which depends on the cooling rate of the whole system. We present the first results on the calculation of the cooling rate of the Renca batholith on the basis of the combination of both thermometric calculations and available crystallization and cooling ages (au)
Takemine, S.; Rikimaru, A.; Takahashi, K.
The rice is one of the staple foods in the world High quality rice production requires periodically collecting rice growth data to control the growth of rice The height of plant the number of stem the color of leaf is well known parameters to indicate rice growth Rice growth diagnosis method based on these parameters is used operationally in Japan although collecting these parameters by field survey needs a lot of labor and time Recently a laborsaving method for rice growth diagnosis is proposed which is based on vegetation cover rate of rice Vegetation cover rate of rice is calculated based on discriminating rice plant areas in a digital camera image which is photographed in nadir direction Discrimination of rice plant areas in the image was done by the automatic binarization processing However in the case of vegetation cover rate calculation method depending on the automatic binarization process there is a possibility to decrease vegetation cover rate against growth of rice In this paper a calculation method of vegetation cover rate was proposed which based on the automatic binarization process and referred to the growth hysteresis information For several images obtained by field survey during rice growing season vegetation cover rate was calculated by the conventional automatic binarization processing and the proposed method respectively And vegetation cover rate of both methods was compared with reference value obtained by visual interpretation As a result of comparison the accuracy of discriminating rice plant areas was increased by the proposed
International Nuclear Information System (INIS)
Liu Yuanzhong
1993-01-01
The calculations of the release of radionuclides to environment are the basis of environmental impact assessment during the normal operation of a module high temperature gas-cooled reactor of the Institute of Nuclear Energy Technology, Tsinghua University, China. According to the features of the reactor it is pointed out that only five sources of the airborne radioactive materials released to environment are important. They are: (1) the activation of the air in the reactor cavity; (2) the escape from the primary coolant systems; (3) the release of radioactively contaminated helium from storage tanks; (4) the release of radioactively contaminated helium from the gas evacuation system of fuel load and unload system; (5) the leakage of the vapour from water-steam loop. In accordance with five release sources the calculating methods of radionuclides released to environment are worked out respectively and the respective calculating formulas are derived for the normal operation of the reactor
Aerosol material release rates from zircaloy-4 at temperatures from 2000 to 22000C
International Nuclear Information System (INIS)
Mulpuru, S.R.; Wren, D.J.; Rondeau, R.K.
1987-01-01
During some postulated severe accidents involving loss of coolant and loss of emergency coolant injection, the temperatures in a CANDU reactor fuel channel become high enough to cause failure and melting of the Zircaloy fuel cladding. At such high temperatures, vapors of fission products and structural (fuel and cladding) materials will be released into the coolant steam and hydrogen mixture. These vapors will condense as cooler conditions are encountered downstream. The vapors from structural materials are relatively involatile; therefore, they will condense readily into aerosol particles. These particles, in turn, will provide sites for the condensation of the more volatile fission products. The aerosol transport of fission products in the primary heat transport system (PHTS) will thus be influenced by the structural material release rates. As part of an ongoing program to develop predictive tools for aerosol and associated fission product transport through the PHTS, experiments have been conducted to measure the vapor mass release rates of the alloying elements from Zircaloy-4 at high temperatures. The paper presents the results and analysis of these experiments
Implementation of Online Promethee Method for Poor Family Change Rate Calculation
Aji, Dhady Lukito; Suryono; Widodo, Catur Edi
2018-02-01
This research has been done online calculation of the rate of poor family change rate by using Preference Ranking Method of Organization Of Enrichment Evaluation (PROMETHEE) .This system is very useful to monitor poverty in a region as well as for administrative services related to poverty rate. The system consists of computer clients and servers connected via the internet network. Poor family residence data obtained from the government. In addition, survey data are inputted through the client computer in each administrative village and also 23 criteria of input in accordance with the established government. The PROMETHEE method is used to evaluate the value of poverty and its weight is used to determine poverty status. PROMETHEE output can also be used to rank the poverty of the registered population of the server based on the netflow value. The poverty rate is calculated based on the current poverty rate compared to the previous poverty rate. The rate results can be viewed online and real time on the server through numbers and graphs. From the test results can be seen that the system can classify poverty status, calculate the poverty rate change rate and can determine the value and poverty ranking of each population.
Implementation of Online Promethee Method for Poor Family Change Rate Calculation
Directory of Open Access Journals (Sweden)
Lukito Aji Dhady
2018-01-01
Full Text Available This research has been done online calculation of the rate of poor family change rate by using Preference Ranking Method of Organization Of Enrichment Evaluation (PROMETHEE .This system is very useful to monitor poverty in a region as well as for administrative services related to poverty rate. The system consists of computer clients and servers connected via the internet network. Poor family residence data obtained from the government. In addition, survey data are inputted through the client computer in each administrative village and also 23 criteria of input in accordance with the established government. The PROMETHEE method is used to evaluate the value of poverty and its weight is used to determine poverty status. PROMETHEE output can also be used to rank the poverty of the registered population of the server based on the netflow value. The poverty rate is calculated based on the current poverty rate compared to the previous poverty rate. The rate results can be viewed online and real time on the server through numbers and graphs. From the test results can be seen that the system can classify poverty status, calculate the poverty rate change rate and can determine the value and poverty ranking of each population.
Application of CFD dispersion calculation in risk based inspection for release of H2S
International Nuclear Information System (INIS)
Sharma, Pavan K.; Vinod, Gopika; Singh, R.K.; Rao, V.V.S.S.; Vaze, K.K.
2011-01-01
In atmospheric dispersion both deterministic and probabilistic approached have been used for addressing design and regulatory concerns. In context of deterministic calculations the amount of pollutants dispersion in the atmosphere is an important area wherein different approaches are followed in development of good analytical model. The analysis based on Computational Fluid Dynamics (CFD) codes offer an opportunity of model development based on first principles of physics and hence such models have an edge over the existing models. In context of probabilistic methods applying risk based inspection (wherein consequence of failure from each component needs to be assessed) are becoming popular. Consequence evaluation in a process plant is a crucial task. Often the number of components considered for life management will be too huge. Also consequence evaluation of all the components proved to be laborious task. The present paper is the results of joint collaborative work from deterministic and probabilistic modelling group working in the field of atmospheric dispersion. Even though API 581 has simplified qualitative approach, regulators find the some of the factors, in particular, quantity factor, not suitable for process plants. Often dispersion calculations for heavy gas are done with very simple model which can not take care of density based atmospheric dispersion. This necessitates a new approach with a CFD based technical basis is proposed, so that the range of quantity considered along with factors used can be justified. The present paper is aimed at bringing out some of the distinct merits and demerits of the CFD based models. A brief account of the applications of such CFD codes reported in literature is also presented in the paper. This paper describes the approach devised and demonstrated for the said issue with emphasis of CFD calculations. (author)
Recent research on stishovite: Hugoniot and partial release Z experiments and DFT EOS calculations
Furnish, Michael; Shulenburger, Luke; Desjarlais, Michael; Fei, Yingwei
2017-06-01
We have conducted a series of ride-along experiments on the Z facility to ascertain the Hugoniot of silica centered in the stishovite phase over a range 0.4 - 1.0 TPa, together with partial release states produced at the interface between the sample and a fused silica window. The stishovite samples were synthesized in a large-volume multi-anvil press at 15 GPa and 1773 K, with an initial density of 4.29 gm/cc. The new Z experiments on stishovite fill in a gap between gas gun experiments and NIF experiments. The states are compared with the Hugoniots of quartz and fused silica for inferences as to EOS. They are generally consistent with Sesame 7360 predictions. Sound speed constraints from these data are discussed. The new Hugoniot data cross over the melting curve of stishovite, providing insight into the properties of solid and liquid under extreme conditions in conjunction with predictions from density-functional theory modeling. These data are fundamentally important for understanding the interior of silicate-based super-Earths. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
A comparison of measured and calculated values of air kerma rates from 137Cs in soil
Directory of Open Access Journals (Sweden)
V. P. Ramzaev
2015-01-01
Full Text Available In 2010, a study was conducted to determine the air gamma dose rate from 137Cs deposited in soil. The gamma dose rate measurements and soil sampling were performed at 30 reference plots from the south-west districts of the Bryansk region (Russia that had been heavily contaminated as a result of the Chernobyl accident. The 137Cs inventory in the top 20 cm of soil ranged from 260 kBq m–2 to 2800 kBq m–2. Vertical distributions of 137Cs in soil cores (6 samples per a plot were determined after their sectioning into ten horizontal layers of 2 cm thickness. The vertical distributions of 137Cs in soil were employed to calculate air kerma rates, K, using two independent methods proposed by Saito and Jacob [Radiat. Prot. Dosimetry, 1995, Vol. 58, P. 29–45] and Golikov et al. [Contaminated Forests– Recent Developments in Risk Identification and Future Perspective. Kluwer Academic Publishers, 1999. – P. 333–341]. A very good coincidence between the methods was observed (Spearman’s rank coefficient of correlation = 0.952; P<0.01; on average, a difference between the kerma rates calculated with two methods did not exceed 3%. The calculated air kerma rates agreed with the measured dose rates in air very well (Spearman’s coefficient of correlation = 0.952; P<0.01. For large grassland plots (n=19, the measured dose rates were on average 6% less than the calculated kerma rates. The tested methods for calculating the air dose rate from 137Cs in soil can be recommended for practical studies in radiology and radioecology.
Evaluation of fuel release rate and mechanism tests under RBCB conditions
International Nuclear Information System (INIS)
Adamson, M.G.
1981-09-01
This task includes theoretical evaluation of fuel/fission product release behavior from failed LMFBR fuel elements as well as an on-going experimental investigation of the mechanism of oxide fuel dispersal into flowing liquid sodium. The primary objectives of this work are to develop a fuel source term that can be used in predictive models for primary heat transfer system contamination and to understand the separate influences of important system variables (such as flow rate, oxygen impurity level) on this source term. The present report is written in two parts: the first, in condensed form, is an updated evaluation of fuel (U,Pu) and fission product release data, and the second describes the current status of supporting experimental work at General Electric's Vallecitos Laboratory
Tomic, I; Vidis-Millward, A; Mueller-Zsigmondy, M; Cardot, J-M
2016-05-30
The objective of this study was development of accelerated in vitro release method for peptide loaded PLGA microspheres using flow-through apparatus and assessment of the effect of dissolution parameters (pH, temperature, medium composition) on drug release rate and mechanism. Accelerated release conditions were set as pH 2 and 45°C, in phosphate buffer saline (PBS) 0.02M. When the pH was changed from 2 to 4, diffusion controlled phases (burst and lag) were not affected, while release rate during erosion phase decreased two-fold due to slower ester bonds hydrolyses. Decreasing temperature from 45°C to 40°C, release rate showed three-fold deceleration without significant change in release mechanism. Effect of medium composition on drug release was tested in PBS 0.01M (200 mOsm/kg) and PBS 0.01M with glucose (380 mOsm/kg). Buffer concentration significantly affected drug release rate and mechanism due to the change in osmotic pressure, while ionic strength did not have any effect on peptide release. Furthermore, dialysis sac and sample-and-separate techniques were used, in order to evaluate significance of dissolution technique choice on the release process. After fitting obtained data to different mathematical models, flow-through method was confirmed as the most appropriate for accelerated in vitro dissolution testing for a given formulation. Copyright © 2016 Elsevier B.V. All rights reserved.
Calculation of heat rating and burn-up for test fuel pins irradiated in DR 3
International Nuclear Information System (INIS)
Bagger, C.; Carlsen, H.; Hansen, K.
1980-01-01
A summary of the DR 3 reactor and HP1 rig design is given followed by a detailed description of the calculation procedure for obtaining linear heat rating and burn-up values of fuel pins irradiated in HP1 rigs. The calculations are carried out rather detailed, especially regarding features like end pellet contribution to power as a function of burn-up, gamma heat contributions, and evaluation of local values of heat rating and burn-up. Included in the report is also a description of the fast flux- and cladding temperature calculation techniques currently used. A good agreement between measured and calculated local burn-up values is found. This gives confidence to the detailed treatment of the data. (author)
International Nuclear Information System (INIS)
2002-01-01
Calculations with the quadratic lineal model for medium rate using the equation dose-effect. Several calculations for system of low dose rate brachytherapy plus teletherapy, calculations for brachytherapy with medium dose rate together with teletherapy, dose for fraction and the one numbers of fractions in medium rate
Large-scale calculations of the beta-decay rates and r-process nucleosynthesis
Energy Technology Data Exchange (ETDEWEB)
Borzov, I N; Goriely, S [Inst. d` Astronomie et d` Astrophysique, Univ. Libre de Bruxelles, Campus Plaine, Bruxelles (Belgium); Pearson, J M [Inst. d` Astronomie et d` Astrophysique, Univ. Libre de Bruxelles, Campus Plaine, Bruxelles (Belgium); [Lab. de Physique Nucleaire, Univ. de Montreal, Montreal (Canada)
1998-06-01
An approximation to a self-consistent model of the ground state and {beta}-decay properties of neutron-rich nuclei is outlined. The structure of the {beta}-strength functions in stable and short-lived nuclei is discussed. The results of large-scale calculations of the {beta}-decay rates for spherical and slightly deformed nuclides of relevance to the r-process are analysed and compared with the results of existing global calculations and recent experimental data. (orig.)
Ramkumar, Prem; Navarro, Sergio Michael
2017-01-01
Objectives: The primary goal of this study was to assess the short-term outcomes among National Football League (NFL) players following concussion in terms of: (1) DNP protocol activation, (2) release rate at one and three years, and (3) mean salary reduction. A secondary goal of the study was to stratify the post-concussive release rate by franchise and player position. Methods: NFL player transaction records and publicly available weekly injury reports from August 2005 to January 2016 for NFL players were analyzed. All players immediately sustaining recorded concussions were evaluated for a change to inactive or do-not-play (DNP) status. The one-year and three-year release rate following concussion was defined as any player transitioning to inactivation, retirement, free agency, or any failure to return for a successive season on the same team’s active roster after one or three years from the initial concussion. Student’s t-test was used to compare release rates between non-concussed and concussed players at one and three years. Mean salary reduction per year following concussion was calculated using publicly available player contracts. Additionally, franchise-level and position-based analyses of the release rate were performed. Results: Of the total 5,451 NFL players retrospectively analyzed over the 11-year period, 373 sustained publicly reported concussions resulting in DNP protocol activation. The release rate of the post-concussive versus non-concussive player was 26% vs. 20% at 1 year (pfranchise to release an athlete following concussion within one and three years. Table 1 reports a position-based analysis in terms of concussion rate, mean salary reduction, and NFL career longevity. Conclusion: Our retrospective study demonstrates that NFL concussions resulting in DNP protocol activation leads to a statistically greater release rate among concussed NFL players than non-concussed players. Released players suffered reduction in year-over-year accumulated
International Nuclear Information System (INIS)
Hoefler, A.; Grebner, H.
1992-01-01
Calculations of leak opening and leak rate for through cracks in piping components have been performed. The analyses are pre- or mostly post-calculations to experiments performed at the HDR facility under PWR operating conditions. Piping components under consideration are small diameter straight pipes with circumferential cracks, pipe bends with longitudinal or circumferential cracks and pipe branches with weldment cracks. The component are loaded by internal pressure and opening as well as closing bending moment. The finite element method and two-phase flow leak rate programs are used for the calculations. Results of the analyses are presented as J-integral values, crack opening displacements and areas and leak rates as well as comparisons to the experimental results. 6 refs., 16 figs., 2 tabs
Comparison of leak opening and leak rate calculations to HDR experimental results
International Nuclear Information System (INIS)
Grebner, H.; Hoefler, A.; Hunger, H.
1993-01-01
During the last years a number of calculations of leak opening and leak rate for through cracks in piping components have been performed. Analyses are pre- or mostly post-calculations to experiments performed at the HDR facility under PWR operating conditions. Piping components under consideration were small diameter straight pipes with circumferential cracks, pipe bends with longitudinal or circumferential cracks and pipe branches with weldment cracks. The components were loaded by internal pressure and opening as well as closing bending moment. The finite element method and two-phase flow leak rate programs were used for the calculations. Results of the analyses are presented as J-integral values, crack opening displacements and areas and leak rates as well as comparisons to the experimental results
Calculation of the gamma-dose rate from a continuously emitted plume
International Nuclear Information System (INIS)
Huebschmann, W.; Papadopoulos, D.
1975-06-01
A computer model is presented which calculates the long term gamma dose rate caused by the radioactive off-gas continuously emitted from a stack. The statistical distribution of the wind direction and velocity and of the stability categories is taken into account. The emitted activity, distributed in the atmosphere according to this statistics, is assumed to be concentrated at the mesh points of a three-dimensional grid. The grid spacing and the integration limits determine the accuracy as well as the computer time needed. When calculating the dose rate in a given wind direction, the contribution of the activity emitted into the neighbouring sectors is evaluated. This influence is demonstrated in the results, which are calculated with a error below 3% and compared to the dose rate distribution curves of the submersion model and the model developed by K.J. Vogt. (orig.) [de
International Nuclear Information System (INIS)
Wienhold, P.; Waelbroeck, F.s; Winter, J.; Ali-Khan, I.
1980-12-01
The tritium inventory in the wall, its escape via permeation and its release in general are evaluated during the operation and later shut-down phases of a tokamak like INTOR by means of the PERI code. No real tritium problem arises after shut-down: simple outgasing techniques at wall temperatures Tsub(W) of approx. 500 0 C should decrease the tritium release rate down to a sufficient low level. Very serious problems are on the other hand expected to arise in the areas of inventory and permeation of tritium during the operation phase: one has the choice between e.g. operating at Tsub(W) = 350 0 C with a quasi-stationary tritium inventory of some 100 grams and a permeation flux phisub(p) approx. 1 gram/day or increasing Tsub(W) to 500 0 C, reducing the inventory down to some grams, but have then a leakage rate by permeation of 35 grams/day. For Tsub(W) = 100 0 C the tritium release into the torus will be intolerable. These figures are confirmed by preliminary measurements on Inconel 600. A suggestion is made as to how to alleviate the problem. (orig.) [de
Somogyi, Dezso; Feiler, Charles E.
1960-01-01
The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.
Relativistic QRPA Calculation of β-Decay Rates of r-process Nuclei
International Nuclear Information System (INIS)
Marketin, T.; Paar, N.; Niksic, T.; Vretenar, D.; Ring, P.
2009-01-01
A systematic, fully self-consistent calculation of β-decay rates is presented, based on a microscopic theoretical framework. Analysis is performed on a large number of nuclei from the valley of β stability towards the neutron drip-line. Nuclear ground state is determined using the Relativistic Hartree-Bogoliubov (RHB) model with density-dependent meson-nucleon coupling constants. Transition rates are calculated within the proton-neutron relativistic quasiparticle RPA (pn-RQRPA) using the same interaction that was used in the RHB equations.
American Society for Testing and Materials. Philadelphia
1989-01-01
1.1 This practice covers the providing of guidance in converting the results of electrochemical measurements to rates of uniform corrosion. Calculation methods for converting corrosion current density values to either mass loss rates or average penetration rates are given for most engineering alloys. In addition, some guidelines for converting polarization resistance values to corrosion rates are provided. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
Calculation of dose-rate conversion factors for external exposure to photons and electrons
International Nuclear Information System (INIS)
Kocher, D.C.
1978-01-01
Methods are presented for the calculation of dose-rate conversion factors for external exposure to photon and electron radiation from radioactive decay. A dose-rate conversion factor is defined as the dose-equivalent rate per unit radionuclide concentration. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each radiation type and exposure mode, dose-rate conversion factors are derived for tissue-equivalent material at the body surface of an exposed individual. In addition, photon dose-rate conversion factors are estimated for 22 body organs. The calculations are based on the assumption that the exposure medium is infinite in extent and that the radionuclide concentration is uniform. The dose-rate conversion factors for immersion in contaminated air and water then follow from the requirement that all of the energy emitted in the radioactive decay is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated at a reference location above a smooth, infinite plane using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air
International Nuclear Information System (INIS)
Cowley, S.C.; Kulsrud, R.M.
1989-11-01
We calculate the fusion reaction rates in molecules of hydrogen isotopes. The rates are calculated analytically (for the first time) as an asymptotic expansion in the ratio of the electron mass to the reduced mass of the nucleii. The fusion rates of the P-D, D-D, and D-T reactions are given for a variable electron mass by a simple analytic formula. However, we do not know any mechanism by which a sufficiently localized electron in solid can have an 'effective mass' large enough to explain the result of Fleischman and Pons (FP). This calculation indicates that P-D rates should exceed D-D rates for D-D fusion rates less than approximately 10 -23 per molecule per second. The D-D fusion rate is enhanced by a factor of 10 5 at 10,000 degree K if the excited vibrational states are populated with a Boltzmann distribution and the rotational excitations suppressed. The suggestion that experimental results could be explained by bombardment of cold deuterons by kilovolt deuterons is shown to be an unlikely from an energetic point of view. 12 refs., 3 figs., 1 tab
Volume 1: Calculating potential to emit releases and doses for FEMP's and NOCs; FINAL
International Nuclear Information System (INIS)
HILL, J.S.
1999-01-01
The purpose of this document is to provide Hanford Site facilities a handbook for estimating potential emissions and the subsequent offsite doses. General guidelines and information are provided to assist personnel in estimating emissions for use with U.S. Department of Energy (DOE) facility effluent monitoring plans (FEMPs) and regulatory notices of construction (NOCs), per 40 Code of Federal Regulations (CFR) Part 61, Subpart H, and Washington Administrative Code (WAC) Chapter 246-247 requirements. This document replaces Unit Dose Calculation Methods and Summary of Facility Effluent Monitoring Plan Determinations (WHC-EP-0498). Meteorological data from 1983 through 1996, 13-year data set, was used to develop the unit dose factors provided by this document, with the exception of two meteorological stations. Meteorological stations 23 and 24, located at Gable Mountain and the 100-F Area, only have data from 1986 through 1996, 10-year data set. The scope of this document includes the following: Estimating emissions and resulting effective dose equivalents (EDE) to a facility's nearest offsite receptor (NOR) for use with NOCs under 40 CFR Part 61, Subpart H, requirements Estimating emissions and resulting EDEs to a facility's or emission unit's NOR for use with NOCs under the WAC Chapter 246-247 requirements Estimating emissions and resulting EDEs to a facility's or emission unit's NOR for use with FEMPs and FEMP determinations under DOE Orders 5400.1 and 5400.5 requirements
Influence of ceramic dental crown coating substrate thickness ratio on strain energy release rate
Khasnulhadi, K.; Daud, R.; Mat, F.; Noor, S. N. F. M.; Basaruddin, K. S.; Sulaiman, M. H.
2017-10-01
This paper presents the analysis of coating substrate thickness ratio effect on the crown coating fracture behaviour. The bi-layer material is examined under four point bending with pre-crack at the bottom of the core material by using finite element. Three different coating thickness of core/substrate was tested which is 1:1, 1:2 and 2:1. The fracture parameters are analysed based on bilayer and homogenous elastic interaction. The result shows that the ratio thickness of core/veneer provided a significant effect on energy release rate.
LEAK: A source term generator for evaluating release rates from leaking vessels
International Nuclear Information System (INIS)
Clinton, J.H.
1994-01-01
An interactive computer code for estimating the rate of release of any one of several materials from a leaking tank or broken pipe leading from a tank is presented. It is generally assumed that the material in the tank is liquid. Materials included in the data base are acetonitrile, ammonia, carbon tetrachloride, chlorine, chlorine trifluoride, fluorine, hydrogen fluoride, nitric acid, nitrogen tetroxide, sodium hydroxide, sulfur hexafluoride, sulfuric acid, and uranium hexafluoride. Materials that exist only as liquid and/or vapor over expected ranges of temperature and pressure can easily be added to the data base file. The Fortran source code for LEAK and the data file are included with this report
Effect of temperature and ph on the drug release rate from a polymer conjugate system
International Nuclear Information System (INIS)
Kenawy, E.; Abdel-Hay, F.I.; El-Newehy, M.H.; Ottenbrite, R.M.
2005-01-01
Hydroximide and A-methylhydroxamic acid of poly(ethylene-altmaleic anhydride) (average MW 100-500 k) were used as a carrier for a new drug delivery system. The synthesis of the hydroximide and N methylhydroxamic acid of poly(ethylene-alt-maleic anhydride) were carried out by chemical modification of poly(ethylene-alt-maleic anhydride) with hydroxylamine and N-methyl hydroxylamine, respectively, in N,N- dimethylformamide at room temperature to yield water soluble copolymer. Ketoprofen was reacted with hydroximide and N-methylhydroxamic acid derivatives of poly(ethylene-alt-maleic anhydride) using dicyclohexylcarbodiimide as condensation agent at -5 degree C to yield water insoluble ketoprofen conjugates. All products were characterized by elemental analysis, FTIR and 1HNMR spectra. The in-vitro ketoprofen release was carried out by UV spectrophotometer at max =260 nm. The results demonstrated the effectiveness of hydroximide and N-methylhydroxamic acid of polyethylene-alt-maleic anhydride) as a drug delivery system. The release rates were studied at various ph and temperatures. The copolymer-drug adducts released the drug very slowly at the low ph found in the stomach thus protecting the drug from the action of high concentrations of digestive acids. These results showed the usefulness of hydroxamic acid polymer-drug conjugates as a new drug delivery system for drugs to be targeted to sites in the GI system
DEFF Research Database (Denmark)
Simone, Angela; Kolarik, Jakub; Iwamatsu, Toshiya
2011-01-01
occupants, it is reasonable to consider both the exergy flows in building and those within the human body. Until now, no data have been available on the relation between human-body exergy consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal...... sensation data, from earlier thermal comfort studies, to calculated human-body exergy consumption rates. The results show that the minimum human body exergy consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation....... Generally, the relationship between air temperature and the exergy consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, exergy...
Axelrod, David
2017-01-01
This paper describes how the discount rate used in present value calculations expresses the preference for sustainability in decision making, and its implication for sustainable economic growth. In essence, the lower the discount rate, the greater the regard for the future, and the more likely we choose behaviors that lead to long-term sustainability. The theoretical framework combines behavioral economics and holonomics, which involve limitations of regard for the future due to constraints o...
Panthere V2: Multipurpose Simulation Software for 3D Dose Rate Calculations
Penessot, Gaël; Bavoil, Éléonore; Wertz, Laurent; Malouch, Fadhel; Visonneau, Thierry; Dubost, Julien
2017-09-01
PANTHERE is a multipurpose radiation protection software developed by EDF to calculate gamma dose rates in complex 3D environments. PANTHERE takes a key role in the EDF ALARA process, enabling to predict dose rates and to organize and optimize operations in high radiation environments. PANTHERE is also used for nuclear waste characterization, transport of nuclear materials, etc. It is used in most of the EDF engineering units and their design service providers and industrial partners.
Yang, Huan; Goudeli, Eirini; Hogan, Christopher J.
2018-04-01
In gas phase synthesis systems, clusters form and grow via condensation, in which a monomer binds to an existing cluster. While a hard-sphere equation is frequently used to predict the condensation rate coefficient, this equation neglects the influences of potential interactions and cluster internal energy on the condensation process. Here, we present a collision rate theory-molecular dynamics simulation approach to calculate condensation probabilities and condensation rate coefficients. We use this approach to examine atomic condensation onto 6-56-atom Au and Mg clusters. The probability of condensation depends upon the initial relative velocity (v) between atom and cluster and the initial impact parameter (b). In all cases, there is a well-defined region of b-v space where condensation is highly probable, and outside of which the condensation probability drops to zero. For Au clusters with more than 10 atoms, we find that at gas temperatures in the 300-1200 K range, the condensation rate coefficient exceeds the hard-sphere rate coefficient by a factor of 1.5-2.0. Conversely, for Au clusters with 10 or fewer atoms and for 14- and 28-atom Mg clusters, as cluster equilibration temperature increases, the condensation rate coefficient drops to values below the hard-sphere rate coefficient. Calculations also yield the self-dissociation rate coefficient, which is found to vary considerably with gas temperature. Finally, calculations results reveal that grazing (high b) atom-cluster collisions at elevated velocity (>1000 m s-1) can result in the colliding atom rebounding (bounce) from the cluster surface or binding while another atom dissociates (replacement). The presented method can be applied in developing rate equations to predict material formation and growth rates in vapor phase systems.
Calculation of radiation dose rates from a spent nuclear fuel shipping cask
International Nuclear Information System (INIS)
Chen, S.Y.; Yuan, Y.C.
1988-01-01
Radiation doses from a spent nuclear fuel cask are usually from various phases of operations during handling, shipping, and storage of the casks. Assessment of such doses requires knowledge of external radiation dose rates at various locations surrounding a cask. Under current practices, dose rates from gamma photons are usually estimated by means of point- or line-source approaches incorporating the conventional buildup factors. Although such simplified approaches may at times be easy to use, their accuracy has not been verified. For example, those simplified methods have not taken into account influencing factors such as the geometry of the cask and the presence of the ground surface, and the effects of these factors on the calculated dose rates are largely unknown. Moreover, similar empirical equations for buildup factors currently do not exist for neutrons. The objective of this study is to use a more accurate approach in calculating radiation dose rates for both neutrons and gamma photons from a spent fuel cask. The calculation utilizes the more sophisticated transport method and takes into account the geometry of the cask and the presence of the ground surface. The results of a detailed study of dose rates in the near field (within 20 meters) are presented and, for easy application, the cask centerline dose rates are fitted into empirical equations at cask centerline distances up to 2000 meters from the surface of the cask
International Nuclear Information System (INIS)
Ni Zhipeng; Wang Liangbin; Li Jiangang; Chen Zhiyou; Zhang Yong; Wang Futang
2008-01-01
An electromagnetic calculation and the parameters of the magnet system of the magnetically confined plasma rocket were established. By using ANSYS code, it was found that the leakage rate depends on the current intensity of the magnet and the change of the magnet position.
Zinth, Jennifer
2018-01-01
Federal requirements stipulate that states and local education agencies annually calculate and report an Adjusted Cohort Graduation Rate, disaggregated by student group. The ACGR includes all students who graduate from high school in four years with a regular high school diploma, plus all students with the most significant cognitive disabilities…
39 CFR 3010.23 - Calculation of percentage change in rates.
2010-07-01
... DOMINANT PRODUCTS Rules for Applying the Price Cap § 3010.23 Calculation of percentage change in rates. (a... Postal Service billing determinants. The Postal Service shall make reasonable adjustments to the billing determinants to account for the effects of classification changes such as the introduction, deletion, or...
20 CFR 10.216 - How is the pay rate for COP calculated?
2010-04-01
... for COP purposes is equal to the employee's regular “weekly” pay (the average of the weekly pay over... occurred during the 45-day period are to be reflected in the weekly pay determination. (b) The weekly pay... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false How is the pay rate for COP calculated? 10...
Moore, Clinton T.; Converse, Sarah J.; Folk, Martin J.; Runge, Michael C.; Nesbitt, Stephen A.
2012-01-01
The release of animals to reestablish an extirpated population is a decision problem that is often attended by considerable uncertainty about the probability of success. Annual releases of captive-reared juvenile Whooping Cranes (Grus americana) were begun in 1993 in central Florida, USA, to establish a breeding, non-migratory population. Over a 12-year period, 286 birds were released, but by 2004, the introduced flock had produced only four wild-fledged birds. Consequently, releases were halted over managers' concerns about the performance of the released flock and uncertainty about the efficacy of further releases. We used data on marked, released birds to develop predictive models for addressing whether releases should be resumed, and if so, under what schedule. To examine the outcome of different release scenarios, we simulated the survival and productivity of individual female birds under a baseline model that recognized age and breeding-class structure and which incorporated empirically estimated stochastic elements. As data on wild-fledged birds from captive-reared parents were sparse, a key uncertainty that confronts release decision-making is whether captive-reared birds and their offspring share the same vital rates. Therefore, we used data on the only population of wild Whooping Cranes in existence to construct two alternatives to the baseline model. The probability of population persistence was highly sensitive to the choice of these three models. Under the baseline model, extirpation of the population was nearly certain under any scenario of resumed releases. In contrast, the model based on estimates from wild birds projected a high probability of persistence under any release scenario, including cessation of releases. Therefore, belief in either of these models suggests that further releases are an ineffective use of resources. In the third model, which simulated a population Allee effect, population persistence was sensitive to the release decision
Results of Propellant Mixing Variable Study Using Precise Pressure-Based Burn Rate Calculations
Stefanski, Philip L.
2014-01-01
A designed experiment was conducted in which three mix processing variables (pre-curative addition mix temperature, pre-curative addition mixing time, and mixer speed) were varied to estimate their effects on within-mix propellant burn rate variability. The chosen discriminator for the experiment was the 2-inch diameter by 4-inch long (2x4) Center-Perforated (CP) ballistic evaluation motor. Motor nozzle throat diameters were sized to produce a common targeted chamber pressure. Initial data analysis did not show a statistically significant effect. Because propellant burn rate must be directly related to chamber pressure, a method was developed that showed statistically significant effects on chamber pressure (either maximum or average) by adjustments to the process settings. Burn rates were calculated from chamber pressures and these were then normalized to a common pressure for comparative purposes. The pressure-based method of burn rate determination showed significant reduction in error when compared to results obtained from the Brooks' modification of the propellant web-bisector burn rate determination method. Analysis of effects using burn rates calculated by the pressure-based method showed a significant correlation of within-mix burn rate dispersion to mixing duration and the quadratic of mixing duration. The findings were confirmed in a series of mixes that examined the effects of mixing time on burn rate variation, which yielded the same results.
Relativistic QRPA calculation of β-decay rates of r-process nuclei
International Nuclear Information System (INIS)
Marketin, T.; Paar, N.; Niksic, T.
2009-01-01
The rapid neutron-capture process (r-process) is responsible for the creation of many nuclei heavier than iron. To describe the r-process, precise data is needed on a large number of neutron-rich nuclei, most of which are not experimentally reachable. One crucial parameter in modeling the nucleosynthesis are the half-lives of the nuclei through which the r-process runs. Therefore, it is of great importance to develop a reliable predictive model which can be applied to the decay of exotic nuclei. A fully self-consistent calculation of β-decay rates is presented, based on a microscopic theoretical framework. Nuclear ground state is determined using the Relativistic Hartree-Bogoliubov (RHB) model with density-dependent meson-nucleon coupling constants. Momentum dependent terms are also included to improve the density of single-particle states around the Fermi level via an increase of the effective nucleon mass [1]. Transition rates are calculated within the proton-neutron relativistic quasiparticle RPA using the same interaction that was used in the RHB equations. In this way no additional parameters are introduced in the RPA calculation. Weak interaction rates are calculated using the current-current formalism previously employed in the study of other astrophysically significant weak processes [2,3], which systematically includes the contributions of forbidden transitions. This theoretical framework will be utilized to study the contributions of forbidden transitions to the total decay rate in several mass regions. We will compare the calculated half-lives for several isotopic chains with previous calculations and experimental data and discuss possible improvements to the model.(author)
Calculation of expected rates of fisheries‐induced evolution in data‐poor situations
DEFF Research Database (Denmark)
Andersen, Ken Haste
2010-01-01
A central part of an impact assessment of the evolutionary effects of fishing is a calculation of the expected rates of fishing induced by current fishing practice and an evaluation of how alternative fishing patterns may reduce evolutionary impacts of fishing. Here a general size-based framework...... for modeling the demography of fish based on size-based prescriptions of natural mortality, growth, and fishing is presented. Life history theory is used to reduce the necessary parameter set by utilizing relations between parameters making the framework particularly well suited for data-poor situations where...... only the size at maturation or the asymptotic size is known. The framework is applied to perform the modeling part of an evolutionary impact assessment using basic quantitative genetics to calculated expected rates of evolution on size at maturation, growth rate, and investment in gonads. A sensitivity...
Hendryx, Michael; Fedorko, Evan
2011-01-01
Background: Potential environmental exposures from chemical manufacturing or industrial sites have not been well studied for rural populations. The current study examines whether chemical releases from facilities monitored through the Toxics Release Inventory (TRI) program are associated with population mortality rates for both rural and urban…
DEFF Research Database (Denmark)
Ferter, Keno; Weltersbach, Marc Simon; Strehlow, Harry Vincent
2013-01-01
Unexpectedly high catch-and-release rates in European marine recreational fisheries: implications for science and management. – ICES Journal of Marine Science, 70: .While catch-and-release (C&R) is a well-known practice in several European freshwater recreational fisheries, studies on the magnitu...
Dose rates from a C-14 source using extrapolation chamber and MC calculations
International Nuclear Information System (INIS)
Borg, J.
1996-05-01
The extrapolation chamber technique and the Monte Carlo (MC) calculation technique based on the EGS4 system have been studied for application for determination of dose rates in a low-energy β radiation field e.g., that from a 14 C source. The extrapolation chamber measurement method is the basic method for determination of dose rates in β radiation fields. Applying a number of correction factors and the stopping power ratio, tissue to air, the measured dose rate in an air volume surrounded by tissue equivalent material is converted into dose to tissue. Various details of the extrapolation chamber measurement method and evaluation procedure have been studied and further developed, and a complete procedure for the experimental determination of dose rates from a 14 C source is presented. A number of correction factors and other parameters used in the evaluation procedure for the measured data have been obtained by MC calculations. The whole extrapolation chamber measurement procedure was simulated using the MC method. The measured dose rates showed an increasing deviation from the MC calculated dose rates as the absorber thickness increased. This indicates that the EGS4 code may have some limitations for transport of very low-energy electrons. i.e., electrons with estimated energies less than 10 - 20 keV. MC calculations of dose to tissue were performed using two models: a cylindrical tissue phantom and a computer model of the extrapolation chamber. The dose to tissue in the extrapolation chamber model showed an additional buildup dose compared to the dose in the tissue model. (au) 10 tabs., 11 ills., 18 refs
Shell model calculations for levels and transition rates in 204Pb and 206Pb
International Nuclear Information System (INIS)
Wang, D.; McEllistrem, M.T.
1990-01-01
Level energies and decay rates of both negative and positive parity levels of 206,204 Pb have been calculated through mixed-configuration shell model calculations using the modified surface delta interaction (MSDI), the Schiffer-True central interaction, and another two-body interaction. These calculations were all carried out with a full six-orbit neutron hole space. The predicted low-lying levels with the MSDI are in excellent agreement with experiments, accounting for the energies, spins, and parities of essentially all levels below 3 MeV excitation energy except known particle-hole collective excitations in both nuclei. Almost all calculated E2 and M1 transition rates are consistent with measured branching ratios for γ-ray decay of excited levels. The comparison of the observed and calculated levels demonstrates the important role played by the neutron-hole i 13/2 configuration in the levels of 204 Pb and 206 Pb, and interprets an apparent discrepancy over the character and energy spacings of 0 + levels in 204 Pb
Clouvas, A; Antonopoulos-Domis, M; Silva, J
2000-01-01
The dose rate conversion factors D/sub CF/ (absorbed dose rate in air per unit activity per unit of soil mass, nGy h/sup -1/ per Bq kg/sup -1/) are calculated 1 m above ground for photon emitters of natural radionuclides uniformly distributed in the soil. Three Monte Carlo codes are used: 1) The MCNP code of Los Alamos; 2) The GEANT code of CERN; and 3) a Monte Carlo code developed in the Nuclear Technology Laboratory of the Aristotle University of Thessaloniki. The accuracy of the Monte Carlo results is tested by the comparison of the unscattered flux obtained by the three Monte Carlo codes with an independent straightforward calculation. All codes and particularly the MCNP calculate accurately the absorbed dose rate in air due to the unscattered radiation. For the total radiation (unscattered plus scattered) the D/sub CF/ values calculated from the three codes are in very good agreement between them. The comparison between these results and the results deduced previously by other authors indicates a good ag...
Energy Technology Data Exchange (ETDEWEB)
Wrede, D E; Dawalibi, H [King Faisal Specialist Hospital and Research Centre, Department of Medical Physics. Riyadh (Saudi Arabia)
1980-01-01
A simple mathematical algorithm is derived from experimental data for dose rates from /sup 137/Cs sources in a finite tissue equivalent medium corresponding to the female pelvis. An analytical expression for a point source of /sup 137/Cs along with a simple numerical integration routine allows for rapid as well as accurate dose rate calculations at points of interest for gynecologic insertions. When compared with theoretical models assuming an infinite unit density medium, the measured dose rates are found to be systematically lower at distances away from a single source; 5 per cent at 2 cm and 10 per cent at 7 cm along the transverse axis. Allowance in the program for print out of dose rates from individual sources to a given point and the feature of source strength modification allows for optimization in terms of increasing the difference in dose rate between reference treatment points and sensitive structures such as the bladder, rectum and colon.
International Nuclear Information System (INIS)
Wrede, D.E.; Dawalibi, H.
1980-01-01
A simple mathematical algorithm is derived from experimental data for dose rates from 137 Cs sources in a finite tissue equivalent medium corresponding to the female pelvis. An analytical expression for a point source of 137 Cs along with a simple numerical integration routine allows for rapid as well as accurate dose rate calculations at points of interest for gynecologic insertions. When compared with theoretical models assuming an infinite unit density medium, the measured dose rates are found to be systematically lower at distances away from a single source; 5 per cent at 2 cm and 10 per cent at 7 cm along the transverse axis. Allowance in the program for print out of dose rates from individual sources to a given point and the feature of source strength modification allows for optimization in terms of increasing the difference in dose rate between reference treatment points and sensitive structures such as the bladder, rectum and colon. (Auth.)
Influence of Groundwater Flow Rate on Nuclide Releases from Pyro-processed Waste Repository
International Nuclear Information System (INIS)
Lee, Youn Myoung; Jeong, Jong Tae
2011-01-01
Since the early 2000s several template programs for the safety assessment of a high-level radioactive waste repository as well as a low- and intermediate level radioactive waste repository systems have been developed by utilizing GoldSim and AMBER at KAERI. Very recently, another template program for a conceptual hybrid-typed repository system, called 'A-KRS' in which two kinds of pyroprocessed radioactive wastes, low-level metal wastes and ceramic high-level wastes that arise from pyroprocessing of PWR nuclear spent fuels has been developed and are to be disposed of by separate disposal strategies. The A-KRS is considered to be constructed at two different depths in geological media: 200m depth, at which a possible human intrusion is considered to be limited after closure, for the pyroprocessed metal wastes with lower or no decay heat producing nuclides, and 500m depth, believed to be in the reducing condition for nuclides with a rather higher radioactivity and heat generation rate. This program is ready for total system performance assessment which is able to evaluate nuclide release from the repository and farther transport into the geosphere and biosphere under various normal, disruptive natural and manmade events, and scenarios that can occur after a failure of waste package and canister. To quantify a nuclide release and transport through the possible various pathways especially in the near-fields of the A-KRS repository system, some illustrative evaluations have been made through the study. Even though all parameter values associated with the A-KRS were assumed for the time being, the illustrative results should be informative since the evaluation of such releases is very important not only in view of the safety assessment of the repository, but also for design feedback of its performance
Comparison of measured and calculated reaction rate distributions in an scwr-like test lattice
Energy Technology Data Exchange (ETDEWEB)
Raetz, Dominik, E-mail: dominik.raetz@psi.ch [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Jordan, Kelly A., E-mail: kelly.jordan@psi.ch [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Murphy, Michael F., E-mail: mike.murphy@psi.ch [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Perret, Gregory, E-mail: gregory.perret@psi.ch [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Chawla, Rakesh, E-mail: rakesh.chawla@psi.ch [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, EPFL (Switzerland)
2011-04-15
High resolution gamma-ray spectroscopy measurements were performed on 61 rods of an SCWR-like fuel lattice, after irradiation in the central test zone of the PROTEUS zero-power research reactor at the Paul Scherrer Institute in Switzerland. The derived reaction rates are the capture rate in {sup 238}U (C{sub 8}) and the total fission rate (F{sub tot}), and also the reaction rate ratio C{sub 8}/F{sub tot}. Each of these has been mapped rod-wise on the lattice and compared to calculated results from whole-reactor Monte Carlo simulations with MCNPX. Ratios of calculated to experimental values (C/E's) have been assessed for the C{sub 8}, F{sub tot} and C{sub 8}/F{sub tot} distributions across the lattice. These C/E's show excellent agreement between the calculations and the measurements. For the {sup 238}U capture rate distribution, the 1{sigma} level in the comparisons corresponds to an uncertainty of {+-}0.8%, while for the total fission rate the corresponding value is {+-}0.4%. The uncertainty for C{sub 8}/F{sub tot}, assessed as a reaction rate ratio characterizing each individual rod position in the test lattice, is significantly higher at {+-}2.2%. To determine the reproducibility of these results, the measurements were performed twice, once in 2006 and again in 2009. The agreement between these two measurement sets is within the respective statistical uncertainties.
Energy Technology Data Exchange (ETDEWEB)
Simone, Angela; Kolarik, Jakub; Olesen, Bjarne W. [ICIEE/BYG, Technical University of Denmark (Denmark); Iwamatsu, Toshiya [Faculty of Urban Environmental Science, Tokyo Metropolitan University (Japan); Asada, Hideo [Architech Consulting Co., Tokyo (Japan); Dovjak, Mateja [Faculty of Civil and Geodetic Engineering, University of Ljubljana (Slovenia); Schellen, Lisje [Eindhoven University of Technology, Faculty of Architecture Building and Planning (Netherlands); Shukuya, Masanori [Laboratory of Building Environment, Tokyo City University, Yokohama (Japan)
2011-01-15
Application of the exergy concept to research on the built environment is a relatively new approach. It helps to optimize climate conditioning systems so that they meet the requirements of sustainable building design. As the building should provide a healthy and comfortable environment for its occupants, it is reasonable to consider both the exergy flows in building and those within the human body. Until now, no data have been available on the relation between human-body exergy consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal sensation data, from earlier thermal comfort studies, to calculated human-body exergy consumption rates. The results show that the minimum human body exergy consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation. Generally, the relationship between air temperature and the exergy consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, exergy consumption rates increase as the operative temperature increases above 24 C or decreases below 22 C. With the data available so far, a second-order polynomial relationship between thermal sensation and the exergy consumption rate was established. (author)
Increased survival rate by local release of diclofenac in a murine model of recurrent oral carcinoma
Directory of Open Access Journals (Sweden)
Will OM
2016-10-01
Full Text Available Olga Maria Will,1,* Nicolai Purcz,2,* Athena Chalaris,3 Carola Heneweer,4,5 Susann Boretius,1 Larissa Purcz,2 Lila Nikkola,6 Nureddin Ashammakhi,6 Holger Kalthoff,7 Claus-Christian Glüer,1 Jörg Wiltfang,2 Yahya Açil,2 Sanjay Tiwari1 1Section Biomedical Imaging, Clinic for Radiology and Neuroradiology, MOIN CC, 2Department of Oral and Maxillofacial Surgery, University Hospital Schleswig-Holstein, 3Institute of Biochemistry, Christian-Albrechts-Universität zu Kiel, 4Clinic for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel, 5Institute for Diagnostic and Interventional Radiology, University Hospital Cologne, Cologne, Germany; 6Department of Biomedical Engineering, Tampere University of Technology, Tampere, Finland; 7Institute for Experimental Cancer Research, University Hospital Schleswig-Holstein, Kiel, Germany *These authors contributed equally to this work Abstract: Despite aggressive treatment with radiation and combination chemotherapy following tumor resection, the 5-year survival rate for patients with head and neck cancer is at best only 50%. In this study, we examined the therapeutic potential of localized release of diclofenac from electrospun nanofibers generated from poly(d,l-lactide-co-glycolide polymer. Diclofenac was chosen since anti-inflammatory agents that inhibit cyclooxygenase have shown great potential in their ability to directly inhibit tumor growth as well as suppress inflammation-mediated tumor growth. A mouse resection model of oral carcinoma was developed by establishing tumor growth in the oral cavity by ultrasound-guided injection of 1 million SCC-9 cells in the floor of the mouth. Following resection, mice were allocated into four groups with the following treatment: 1 no treatment, 2 implanted scaffolds without diclofenac, 3 implanted scaffolds loaded with diclofenac, and 4 diclofenac given orally. Small animal ultrasound and magnetic resonance imaging were utilized for longitudinal
Rate maximum calculation of Dpa in CNA-II pressure vessel
International Nuclear Information System (INIS)
Mascitti, J. A
2012-01-01
The maximum dpa rate was calculated for the reactor in the following state: fresh fuel, no Xenon, a Boron concentration of 15.3 ppm, critical state, its control rods in the criticality position, hot, at full power (2160 MW). It was determined that the maximum dpa rate under such conditions is 3.54(2)x10 12 s -1 and it is located in the positions corresponding to θ=210 o in the azimuthal direction, and z=20 cm and -60 cm respectively in the axial direction, considering the calculation mesh centered at half height of the fuel element (FE) active length. The dpa rate spectrum was determined as well as the contribution to it for 4 energy groups: a thermal group, two epithermal groups and a fast one. The maximum dpa rate considering the photo-neutrons production from (γ, n) reaction in the heavy water of coolant and moderator was 3.93(4)x10 12 s -1 that is 11% greater than the obtained without photo-neutrons. This verified significant difference between both cases, suggest that photo-neutrons in large heavy water reactors such as CNA-II should not be ignored. The maximum DPA rate in the first mm of the reactor pressure vessel was calculated too and it was obtained a value of 4.22(6)x10 12 s -1 . It should be added that the calculation was carried out with the reactor complete accurate model, with no approximations in spatial or energy variables. Each value has, between parentheses, a percentage relative error representing the statistical uncertainty due to the probabilistic Monte Carlo method used to estimate it. More representative values may be obtained with this method if equilibrium burn-up distribution is used (author)
2013-06-01
was recorded. Figure 14 shows the gauge on the rocker arm during calibration . Figure 14. Mechanical Injector Rocker Arm Strain Gauge. D. DATA...RELEASE RATE COMPARISON OF ALGAE HYDROPROCESSED RENEWABLE DIESEL TO F-76 IN A TWO-STROKE DIESEL ENGINE by John H. Petersen June 2013 Thesis...RELEASE RATE COMPARISON OF ALGAE HYDROPROCESSED RENEWABLE DIESEL TO F-76 IN A TWO-STROKE DIESEL ENGINE 5. FUNDING NUMBERS 6. AUTHOR(S) John H
Calculation of the soft error rate of submicron CMOS logic circuits
International Nuclear Information System (INIS)
Juhnke, T.; Klar, H.
1995-01-01
A method to calculate the soft error rate (SER) of CMOS logic circuits with dynamic pipeline registers is described. This method takes into account charge collection by drift and diffusion. The method is verified by comparison of calculated SER's to measurement results. Using this method, the SER of a highly pipelined multiplier is calculated as a function of supply voltage for a 0.6 microm, 0.3 microm, and 0.12 microm technology, respectively. It has been found that the SER of such highly pipelined submicron CMOS circuits may become too high so that countermeasures have to be taken. Since the SER greatly increases with decreasing supply voltage, low-power/low-voltage circuits may show more than eight times the SER for half the normal supply voltage as compared to conventional designs
Decay heat rates calculated using ORIGEN-S and CINDER10 with common data libraries
International Nuclear Information System (INIS)
Brady, M.C.; Hermann, O.W.; Beard, C.A.; Bohnhoff, W.J.; England, T.R.
1991-01-01
A set of two benchmark problems were proposed as part of an international comparison of decay heat codes. Problem specifications included explicit fission-yield, decay and capture data libraries to be used in the calculations. This paper describes the results obtained using these common data to perform the benchmark calculations with two popular depletion codes, ORIGEN-S and CINDER10. Short descriptions of the methods used by each of these codes are also presented. Results from other contributors to the international comparison are discussed briefly. This comparison of decay heat codes using common data libraries demonstrates that discrepant results in calculated decay heat rates are the result of differences in the nuclear data input to the codes and not the method of solution. 15 refs., 2 figs., 8 tabs
International Nuclear Information System (INIS)
Oishi, Koji; Minami, Kiyoshi; Ikeda, Yujiro; Kosako, Kazuaki; Nakamura, Tomoo
1991-01-01
A concrete assembly was irradiated by D-T neutrons for 10 h, and dose rate measurement one day after shutdown has been carried out in order to provide a guide line for selection studies of low activation concrete. The experimental results were analyzed by the two dimensional calculation code DOT3.5 with its related nuclear data library GICX40 based on ENDF/B-III, however disagreement between experiment and calculation was observed in the deeper detector positions. Calculations were also performed using the nuclear data library based on ENDF/B-IV, and agreement within experimental errors was obtained at all detector positions. Selection studies for low activation concrete were performed using this nuclear data library. As a result, it was found that limestone concrete exhibited excellent properties as a low activation concrete in fusion facilities. (orig.)
Extended calculations of energies, transition rates, and lifetimes for F-like Kr XXVIII
Zhang, C. Y.; Si, R.; Yao, K.; Gu, M. F.; Wang, K.; Chen, C. Y.
2018-02-01
The excitation energies, lifetimes, wavelengths and E1, E2, M1 and M2 transition rates for the lowest 389 levels of the 2l7, 2l63l‧, 2l64l‧, and 2l65l‧ configurations from second-order many-body perturbation theory (MBPT) calculations, and the results for the lowest 200 states of the 2l7, 2l63l‧, and 2l64l‧ configurations from multi-configuration Dirac-Hartree-Fock (MCDHF) calculations in F-like Kr XXVIII are presented in this work. The relative differences between our two sets of level energies are mostly within 0.005% for the lowest 200 levels. Comparisons are made with experimental and other available theoretical results to assess the reliability and accuracy of the present calculations. We believe them to be the most complete and accurate results for Kr XXVIII at present.
Sensitivity of performance assessment of the engineered barriers to nuances of release rate criteria
International Nuclear Information System (INIS)
Oliver, D.L.R.
1987-01-01
The United States Nuclear Regulatory Commission (NRC) has established criteria for the long-term performance of proposed high-level waste repositories. As with any regulation, the criteria may be interpreted in several ways. Due to the high capital costs and the emotional political climate associated with any high-level radioactive waste repository, it is important that there be an early consensus regarding interpretations of the criteria, and what assumptions may be used to demonstrate compliance with them. This work uses analytic solutions of mass transport theory to demonstrate how sensitive performance analyses are to various nuances of the NRC release rate criterion for the engineered barriers. The analysis is directed at the proposed repository in basalt at the Hanford site in Washington State
The critical release rates for the dissociating gas N204/N02/N0
International Nuclear Information System (INIS)
Porter, W.H.L.
1979-03-01
Dissociating vapour systems have certain characteristics which make them attractive as coolants, notably a large effective specific heat which is significantly greater than that for the individual components of the gas mixture, and also an enhanced boundary layer heat transfer coefficient resulting from the physical characteristics of thermal dissociation. In part these effects ensure that a dissociating gas has a greatly improved thermal capacity and heat transfer capability when compared with most inert gases. In this report the critical release rates for the dissociating vapour system N 2 0 4 -N0 2 -N0 are established, principally in the two phase region, and the thermodynamics of nitrogen tetroxide are examined. (U.K.)
Calculation of hydrogen outgassing rate of LHD by recombination limited model
International Nuclear Information System (INIS)
Akaishi, K.; Nakasuga, M.
2002-04-01
To simulate hydrogen outgassing in the plasma vacuum vessel of LHD, the recombination limited model is presented, where the time evolution of hydrogen concentration in the wall of the plasma vacuum vessel is described by a one-dimensional diffusion equation. The hydrogen outgassing rates when the plasma vacuum vessel is pumped down at room temperature and baked at 100 degC are calculated as a function of pumping time. The calculation shows that the hydrogen outgassing rate of the plasma vacuum vessel can be reduced at least by one order of magnitude due to pumping and baking. This prediction is consistent with the recent result of outgassing reduction observed in the pumping-down and baking of the plasma vacuum vessel in LHD. (author)
External dose-rate conversion factors for calculation of dose to the public
Energy Technology Data Exchange (ETDEWEB)
1988-07-01
This report presents a tabulation of dose-rate conversion factors for external exposure to photons and electrons emitted by radionuclides in the environment. This report was prepared in conjunction with criteria for limiting dose equivalents to members of the public from operations of the US Department of Energy (DOE). The dose-rate conversion factors are provided for use by the DOE and its contractors in performing calculations of external dose equivalents to members of the public. The dose-rate conversion factors for external exposure to photons and electrons presented in this report are based on a methodology developed at Oak Ridge National Laboratory. However, some adjustments of the previously documented methodology have been made in obtaining the dose-rate conversion factors in this report. 42 refs., 1 fig., 4 tabs.
Directory of Open Access Journals (Sweden)
N. Cai
2012-01-01
Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.
Results of a bench mark test on the crack opening and leak rate calculation
International Nuclear Information System (INIS)
Grebner, H.
1995-01-01
Results of a bench mark test on the standard problem calculation of crack opening and leak rate in piping components are presented. The bench mark test is based on two experiments performed in phase III of the German HDR safety program. The pipe sections considered in these experiments were a straight pipe with an 80 mm diameter containing a circumferential wall penetrating crack and a pipe branch DN 100/DN 25 with a crack in the weldment between the nozzle and the main pipe. Both test pieces were made of austenitic steel and were loaded by internal pressure and bending moment. For the evaluation of the crack opening either analytical methods or estimation schemes or the finite element method were used, while leak rates were calculated by means of two-phase flow methods. The compilation of the results shows very large scatter bands in general, with deviations between calculated and measured values of up to some one hundred percent. Reasons for this behaviour are uncertainties in the measured data and their evaluation as well as the different methods of calculation and their uncertainties. (author)
Preliminary results on food consumption rates for off-site dose calculation of nuclear power plants
International Nuclear Information System (INIS)
Lee, Gab Bock; Chung, Yang Geun; Bang, Sun Young; Kang, Duk Won
2005-01-01
The Internal dose by food consumption mostly account for radiological dose of public around nuclear power plants(NPP). But, food consumption rate applied to off-site dose calculation in Korea which is the result of field investigation around Kori NPP by the KAERI in 1988. is not reflected of the latest dietary characteristics. The Ministry of Health and Welfare Affairs has investigated the food and nutrition of nations every 3 years based on the Law of National Health Improvement. To update the food consumption rates of the maximum individual, the analysis of the national food investigation results and field surveys around nuclear power plant sites have been carried out
Assessments of fluid friction factors for use in leak rate calculations
Energy Technology Data Exchange (ETDEWEB)
Chivers, T.C. [Berkeley Technology Centre, Glos (United Kingdom)
1997-04-01
Leak before Break procedures require estimates of leakage, and these in turn need fluid friction to be assessed. In this paper available data on flow rates through idealized and real crack geometries are reviewed in terms of a single friction factor k It is shown that for {lambda} < 1 flow rates can be bounded using correlations in terms of surface R{sub a} values. For {lambda} > 1 the database is less precise, but {lambda} {approx} 4 is an upper bound, hence in this region flow calculations can be assessed using 1 < {lambda} < 4.
2013-01-08
... DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Quarterly IRS Interest Rates... the public of the quarterly Internal Revenue Service interest rates used to calculate interest on... beginning January 1, 2013, the interest rates for [[Page 1223
Calculation of neutron and gamma-ray flux-to-dose-rate conversion factors
International Nuclear Information System (INIS)
Kwon, S.G.; Lee, S.Y.; Yook, C.C.
1981-01-01
This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute (ANSI) N666. These data are used to calculate the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoenergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions. (author)
Calculation of nuclear-spin-relaxation rate for spin-polarized atomic hydrogen
International Nuclear Information System (INIS)
Ahn, R.M.C.; Eijnde, J.P.H.W.V.; Verhaar, B.J.
1983-01-01
Approximations introduced in previous calculations of spin relaxation for spin-polarized atomic hydrogen are investigated by carrying out a more exact coupled-channel calculation. With the exception of the high-temperature approximation, the approximations turn out to be justified up to the 10 -3 level of accuracy. It is shown that at the lowest temperatures for which experimental data are available, the high-temperature limit underestimates relaxation rates by a factor of up to 2. For a comparison with experimental data it is also of interest to pay attention to the expression for the atomic hydrogen relaxation rates in terms of transition amplitudes for two-particle collisions. Discrepancies by a factor of 2 among previous derivations of relaxation rates are pointed out. To shed light on these discrepancies we present two alternative derivations in which special attention is paid to identical-particle aspects. Comparing with experiment, we find our theoretical volume relaxation rate to be in better agreement with measured values than that obtained by other groups. The theoretical surface relaxation rate, however, still shows a discrepancy with experiment by a factor of order 50
Arbib, Zouhayr; de Godos Crespo, Ignacio; Corona, Enrique Lara; Rogalla, Frank
2017-06-01
Microalgae culture in high rate algae ponds (HRAP) is an environmentally friendly technology for wastewater treatment. However, for the implementation of these systems, a better understanding of the oxygenation potential and the influence of climate conditions is required. In this work, the rates of oxygen production, consumption, and exchange with the atmosphere were calculated under varying conditions of solar irradiance and dilution rate during six months of operation in a real scale unit. This analysis allowed determining the biological response of these dynamic systems. The rates of oxygen consumption measured were considerably higher than the values calculated based on the organic loading rate. The response to light intensity in terms of oxygen production in the bioreactor was described with one of the models proposed for microalgae culture in dense concentrations. This model is based on the availability of light inside the culture and the specific response of microalgae to this parameter. The specific response to solar radiation intensity showed a reasonable stability in spite of the fluctuations due to meteorological conditions. The methodology developed is a useful tool for optimization and prediction of the performance of these systems.
Calculation of fluence rate distributions in a pre design clinical facility for BNCT at the LFR
International Nuclear Information System (INIS)
Peeters, T.T.J.M.; Freudenreich, W.E.
1995-12-01
In a previous study [1], it was demonstrated that the creation of a thermal neutron facility for clinical BNCT in the LFR is feasible. Monte Carlo calculations had shown that the neutron fluence rates and gamma dose rates at the detector position of a model representing a first outline of a clinical facility met all requirements that are necessary for clinical BNCT. In order to gain more information about the neutron fluence rates at several positions, a second step is required. Calculations have been performed for the free beam and for a tumour bearing phantom at 5 cm and 10 cm distance from the irradiation window. Due to thermalization and back scattering, the thermal fluence rates in the tumour at 5 and 10 cm distance from the bismuth shield appeared to be approximately twice as high as the thermal fluence rates in the free beam at the corresponding positions of 5 to 6 cm and 10 to 11 cm from the irradiation window. (orig.)
International Nuclear Information System (INIS)
Gomes, Renato G.; Rebello, Wilson F.; Vellozo, Sergio O.; Junior, Luis M.; Vital, Helio C.; Rusin, Tiago; Silva, Ademir X.
2013-01-01
MCNPX simulations have been performed in order to calculate dose rates as well as spectra along the four experimental channels of the gamma irradiating facility at the Technology Center of the Brazilian Army (CTEx). Safety, operational and research requirements have led to the need to determine both the magnitude and spectra of the leaking gamma fluxes. The CTEx experimental facility is cavity type with a moveable set of 28 horizontally positioned rods, filled with Cesium-137 chloride and doubly encased in stainless steel that yields an approximately plane 42 kCi-source that provides a maximum dose rate of about 1.5 kG/h into two irradiating chambers. The channels are intended for irradiation tests outside facility. They would allow larger samples to be exposed to lower gamma dose rates under controlled conditions. Dose rates have been calculated for several positions inside the channels as well as at their exits. In addition, for purposes related to the safety of operators and personnel, the angles submitted by the exiting beams have also been evaluated as they spread when leaving the channels. All calculations have been performed by using a computational model of the CTEx facility that allows its characteristics and operation to be accurately simulated by using the Monte Carlo Method. Virtual dosimeters filled with Fricke (ferrous sulfate) were modeled and positioned throughout 2 vertical channels (top and bottom) and 2 horizontal ones (front and back) in order to map dose rates and gamma spectrum distributions. The calculations revealed exiting collimated beams in the order of tenths of Grays per minute as compared to the maximum 25 Gy / min dose rate in the irradiator chamber. In addition, the beams leaving the two vertical channels were found to exhibit a widespread cone-shaped distribution with aperture angle ranging around 85 deg. The data calculated in this work are intended for use in the design of optimized experiments (better positioning of samples and
International Nuclear Information System (INIS)
Matijevic, M.; Grgic, D.; Jecmenica, R.
2016-01-01
This paper presents comparison of the Krsko Power Plant simplified Spent Fuel Pool (SFP) dose rates using different computational shielding methodologies. The analysis was performed to estimate limiting gamma dose rates on wall mounted level instrumentation in case of significant loss of cooling water. The SFP was represented with simple homogenized cylinders (point kernel and Monte Carlo (MC)) or cuboids (MC) using uranium, iron, water, and dry-air as bulk region materials. The pool is divided on the old and new section where the old one has three additional subsections representing fuel assemblies (FAs) with different burnup/cooling time (60 days, 1 year and 5 years). The new section represents the FAs with the cooling time of 10 years. The time dependent fuel assembly isotopic composition was calculated using ORIGEN2 code applied to the depletion of one of the fuel assemblies present in the pool (AC-29). The source used in Microshield calculation is based on imported isotopic activities. The time dependent photon spectra with total source intensity from Microshield multigroup point kernel calculations was then prepared for two hybrid deterministic-stochastic sequences. One is based on SCALE/MAVRIC (Monaco and Denovo) methodology and another uses Monte Carlo code MCNP6.1.1b and ADVANTG3.0.1. code. Even though this model is a fairly simple one, the layers of shielding materials are thick enough to pose a significant shielding problem for MC method without the use of effective variance reduction (VR) technique. For that purpose the ADVANTG code was used to generate VR parameters (SB cards in SDEF and WWINP file) for MCNP fixed-source calculation using continuous energy transport. ADVATNG employs a deterministic forward-adjoint transport solver Denovo which implements CADIS/FW-CADIS methodology. Denovo implements a structured, Cartesian-grid SN solver based on the Koch-Baker-Alcouffe parallel transport sweep algorithm across x-y domain blocks. This was first
Resolving an ostensible inconsistency in calculating the evaporation rate of sessile drops.
Chini, S F; Amirfazli, A
2017-05-01
This paper resolves an ostensible inconsistency in the literature in calculating the evaporation rate for sessile drops in a quiescent environment. The earlier models in the literature have shown that adapting the evaporation flux model for a suspended spherical drop to calculate the evaporation rate of a sessile drop needs a correction factor; the correction factor was shown to be a function of the drop contact angle, i.e. f(θ). However, there seemed to be a problem as none of the earlier models explicitly or implicitly mentioned the evaporation flux variations along the surface of a sessile drop. The more recent evaporation models include this variation using an electrostatic analogy, i.e. the Laplace equation (steady-state continuity) in a domain with a known boundary condition value, or known as the Dirichlet problem for Laplace's equation. The challenge is that the calculated evaporation rates using the earlier models seemed to differ from that of the recent models (note both types of models were validated in the literature by experiments). We have reinvestigated the recent models and found that the mathematical simplifications in solving the Dirichlet problem in toroidal coordinates have created the inconsistency. We also proposed a closed form approximation for f(θ) which is valid in a wide range, i.e. 8°≤θ≤131°. Using the proposed model in this study, theoretically, it was shown that the evaporation rate in the CWA (constant wetted area) mode is faster than the evaporation rate in the CCA (constant contact angle) mode for a sessile drop. Copyright © 2016 Elsevier B.V. All rights reserved.
Effects of sample size on estimates of population growth rates calculated with matrix models.
Directory of Open Access Journals (Sweden)
Ian J Fiske
Full Text Available BACKGROUND: Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. METHODOLOGY/PRINCIPAL FINDINGS: Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. CONCLUSIONS/SIGNIFICANCE: We found significant bias at small sample sizes when survival was low (survival = 0.5, and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high
Effects of sample size on estimates of population growth rates calculated with matrix models.
Fiske, Ian J; Bruna, Emilio M; Bolker, Benjamin M
2008-08-28
Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. We found significant bias at small sample sizes when survival was low (survival = 0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities.
Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release
DEFF Research Database (Denmark)
Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.
2008-01-01
Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...
Static and dynamic strain energy release rates in toughened thermosetting composite laminates
Cairns, Douglas S.
1992-01-01
In this work, the static and dynamic fracture properties of several thermosetting resin based composite laminates are presented. Two classes of materials are explored. These are homogeneous, thermosetting resins and toughened, multi-phase, thermosetting resin systems. Multi-phase resin materials have shown enhancement over homogenous materials with respect to damage resistance. The development of new dynamic tests are presented for composite laminates based on Width Tapered Double Cantilevered Beam (WTDCB) for Mode 1 fracture and the End Notched Flexure (ENF) specimen. The WTDCB sample was loaded via a low inertia, pneumatic cylinder to produce rapid cross-head displacements. A high rate, piezo-electric load cell and an accelerometer were mounted on the specimen. A digital oscilloscope was used for data acquisition. Typical static and dynamic load versus displacement plots are presented. The ENF specimen was impacted in three point bending with an instrumented impact tower. Fracture initiation and propagation energies under static and dynamic conditions were determined analytically and experimentally. The test results for Mode 1 fracture are relatively insensitive to strain rate effects for the laminates tested in this study. The test results from Mode 2 fracture indicate that the toughened systems provide superior fracture initiation and higher resistance to propagation under dynamic conditions. While the static fracture properties of the homogeneous systems may be relatively high, the apparent Mode 2 dynamic critical strain energy release rate drops significantly. The results indicate that static Mode 2 fracture testing is inadequate for determining the fracture performance of composite structures subjected to conditions such as low velocity impact. A good correlation between the basic Mode 2 dynamic fracture properties and the performance is a combined material/structural Compression After Impact (CAI) test is found. These results underscore the importance of
Energy Technology Data Exchange (ETDEWEB)
Nordenfors, C
1999-02-01
To determine dose rate in a gamma radiation field, based on measurements with a semiconductor detector, it is necessary to know how the detector effects the field. This work aims to describe this effect with Monte Carlo simulations and calculations, that is to identify the detector response function. This is done for a germanium gamma detector. The detector is normally used in the in-situ measurements that is carried out regularly at the department. After the response function is determined it is used to reconstruct a spectrum from an in-situ measurement, a so called unfolding. This is done to be able to calculate fluence rate and dose rate directly from a measured (and unfolded) spectrum. The Monte Carlo code used in this work is EGS4 developed mainly at Stanford Linear Accelerator Center. It is a widely used code package to simulate particle transport. The results of this work indicates that the method could be used as-is since the accuracy of this method compares to other methods already in use to measure dose rate. Bearing in mind that this method provides the nuclide specific dose it is useful, in radiation protection, since knowing what the relations between different nuclides are and how they change is very important when estimating the risks
Calculating in situ degradation rates of hydrocarbon compounds in deep waters of the Gulf of Mexico.
Thessen, Anne E; North, Elizabeth W
2017-09-15
Biodegradation is an important process for hydrocarbon weathering that influences its fate and transport, yet little is known about in situ biodegradation rates of specific hydrocarbon compounds in the deep ocean. Using data collected in the Gulf of Mexico below 700m during and after the Deepwater Horizon oil spill, we calculated first-order degradation rate constants for 49 hydrocarbons and inferred degradation rate constants for an additional 5 data-deficient hydrocarbons. Resulting calculated (not inferred) half-lives of the hydrocarbons ranged from 0.4 to 36.5days. The fastest degrading hydrocarbons were toluene (k=-1.716), methylcyclohexane (k=-1.538), benzene (k=-1.333), and C1-naphthalene (k=-1.305). The slowest degrading hydrocarbons were the large straight-chain alkanes, C-26 through C-33 (k=-0.0494 through k=-0.007). Ratios of C-18 to phytane supported the hypothesis that the primary means of degradation in the subsurface was microbial biodegradation. These degradation rate constants can be used to improve models describing the fate and transport of hydrocarbons in the event of an accidental deep ocean oil spill. Copyright © 2017 Elsevier Ltd. All rights reserved.
Error rate of automated calculation for wound surface area using a digital photography.
Yang, S; Park, J; Lee, H; Lee, J B; Lee, B U; Oh, B H
2018-02-01
Although measuring would size using digital photography is a quick and simple method to evaluate the skin wound, the possible compatibility of it has not been fully validated. To investigate the error rate of our newly developed wound surface area calculation using digital photography. Using a smartphone and a digital single lens reflex (DSLR) camera, four photographs of various sized wounds (diameter: 0.5-3.5 cm) were taken from the facial skin model in company with color patches. The quantitative values of wound areas were automatically calculated. The relative error (RE) of this method with regard to wound sizes and types of camera was analyzed. RE of individual calculated area was from 0.0329% (DSLR, diameter 1.0 cm) to 23.7166% (smartphone, diameter 2.0 cm). In spite of the correction of lens curvature, smartphone has significantly higher error rate than DSLR camera (3.9431±2.9772 vs 8.1303±4.8236). However, in cases of wound diameter below than 3 cm, REs of average values of four photographs were below than 5%. In addition, there was no difference in the average value of wound area taken by smartphone and DSLR camera in those cases. For the follow-up of small skin defect (diameter: <3 cm), our newly developed automated wound area calculation method is able to be applied to the plenty of photographs, and the average values of them are a relatively useful index of wound healing with acceptable error rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
A comparative study of different methods for calculating electronic transition rates
Kananenka, Alexei A.; Sun, Xiang; Schubert, Alexander; Dunietz, Barry D.; Geva, Eitan
2018-03-01
We present a comprehensive comparison of the following mixed quantum-classical methods for calculating electronic transition rates: (1) nonequilibrium Fermi's golden rule, (2) mixed quantum-classical Liouville method, (3) mean-field (Ehrenfest) mixed quantum-classical method, and (4) fewest switches surface-hopping method (in diabatic and adiabatic representations). The comparison is performed on the Garg-Onuchic-Ambegaokar benchmark charge-transfer model, over a broad range of temperatures and electronic coupling strengths, with different nonequilibrium initial states, in the normal and inverted regimes. Under weak to moderate electronic coupling, the nonequilibrium Fermi's golden rule rates are found to be in good agreement with the rates obtained via the mixed quantum-classical Liouville method that coincides with the fully quantum-mechanically exact results for the model system under study. Our results suggest that the nonequilibrium Fermi's golden rule can serve as an inexpensive yet accurate alternative to Ehrenfest and the fewest switches surface-hopping methods.
Small groups, large profits: Calculating interest rates in community-managed microfinance
DEFF Research Database (Denmark)
Rasmussen, Ole Dahl
2012-01-01
Savings groups are a widely used strategy for women’s economic resilience – over 80% of members worldwide are women, and in the case described here, 72.5%. In these savings groups it is common to see the interest rate on savings reported as "20-30% annually". Using panel data from 204 groups...... in Malawi, I show that the right figure is likely to be at least twice this figure. For these groups, the annual return is 62%. The difference comes from sector-wide application of a non-standard interest rate calculations and unrealistic assumptions about the savings profile in the groups. As a result......, it is impossible to compare returns in savings groups with returns elsewhere. Moreover, the interest on savings is incomparable to the interest rate on loans. I argue for the use of a standardized comparable metric and suggest easy ways to implement it. Developments of new tools and standard along these lines...
Radiological dose rate calculations for the International Thermonuclear Experimental Reactor (ITER)
International Nuclear Information System (INIS)
Khater, H.Y.; Santoro, R.T.
1996-01-01
Two-dimensional biological dose rates were calculated at different locations outside the International Thermonuclear Experimental Reactor (ITER) design. An 18 degree sector of the reactor was modeled in r-θ geometry. The calculations were performed for three different pulsing scenarios. This included a single pulse of 1000 s duration, 10 pulses of 1000 s duration with a 50% duty factor, and 9470 pulses of 1000 s duration with a 50% duty factor for a total fluence of 0.3 MW.a/m 2 . The dose rates were calculated as a function of toroidal angle at locations in the space between the toroidal field (TF) coils and cryostat, and in the space between the cryostat and the biological shield. The two-dimensional results clearly showed the toroidal effect, which is dominated by contribution from the activation of the cryostat and the biological shield. After one pulse, full access to the machine is possible within a few hours following shutdown. After 10 pulses, full access is also possible within the first day following shutdown. At the end of the Basic Performance Phase (BPP), full access is possible at any of the locations considered after one week following shutdown. 5 refs., 5 figs., 2 tabs
Experimental validation of calculated capture rate for nucleus involved in fuel cycle
International Nuclear Information System (INIS)
Benslimane-Bouland, A.
1997-01-01
This work has been realized in the framework of the estimation of actinides and fission products nuclear data for the today and future reactors. The first part presents the existing integral experiments for the calculated capture rate and the methods used in the design of reactor cores calculation formulary. The second part is devoted to the interpretation of three specific irradiation experiments which allow the evaluation of the today knowledge on studied data and their associated uncertainties. The last part presents a synthesis of results and the statistical methods used for the adjustment of data bases. This work shows that, in spite of the reactors Physics progresses on the knowledge of uranium and plutonium capture cross sections, uncertainties remain for minor actinides. (A.L.B.)
Benchmarking of MCNP for calculating dose rates at an interim storage facility for nuclear waste.
Heuel-Fabianek, Burkhard; Hille, Ralf
2005-01-01
During the operation of research facilities at Research Centre Jülich, Germany, nuclear waste is stored in drums and other vessels in an interim storage building on-site, which has a concrete shielding at the side walls. Owing to the lack of a well-defined source, measured gamma spectra were unfolded to determine the photon flux on the surface of the containers. The dose rate simulation, including the effects of skyshine, using the Monte Carlo transport code MCNP is compared with the measured dosimetric data at some locations in the vicinity of the interim storage building. The MCNP data for direct radiation confirm the data calculated using a point-kernel method. However, a comparison of the modelled dose rates for direct radiation and skyshine with the measured data demonstrate the need for a more precise definition of the source. Both the measured and the modelled dose rates verified the fact that the legal limits (<1 mSv a(-1)) are met in the area outside the perimeter fence of the storage building to which members of the public have access. Using container surface data (gamma spectra) to define the source may be a useful tool for practical calculations and additionally for benchmarking of computer codes if the discussed critical aspects with respect to the source can be addressed adequately.
Schmidt, Alice; Aurich, Jörg; Möstl, Erich; Müller, Jürgen; Aurich, Christine
2010-09-01
Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions (n=9) and mares (n=7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations, beat-to-beat (RR) interval and heart rate variability (HRV) were determined. The HRV variables standard deviation of the RR interval (SDRR), RMSSD (root mean square of successive RR differences) and the geometric means standard deviation 1 (SD1) and 2 (SD2) were calculated. Nearly each training unit was associated with an increase in salivary cortisol concentrations (pHRV variables SDRR, RMSSD and SD1 decreased in response to training and lowest values were reached during mounting of a rider (pHRV variables increased again. In contrast, SD2 increased with the beginning of lunging (p<0.05) and no changes in response to mounting were detectable. In conclusion, initial training is a stressor for horses. The most pronounced reaction occurred in response to mounting by a rider, a situation resembling a potentially lethal threat under natural conditions. Copyright (c) 2010 Elsevier Inc. All rights reserved.
Quantum chemical and conventional TST calculations of rate constants for the OH + alkane reaction
International Nuclear Information System (INIS)
Bravo-Perez, Graciela; Alvarez-Idaboy, J. Raul; Jimenez, Annia Galano; Cruz-Torres, Armando
2005-01-01
Reactions of OH with methane, ethane, propane, i-butane, and n-butane have been modeled using ab initio (MP2) and hybrid DFT (BHandHLYP) methods, and the 6-311G(d,p) basis set. Furthermore, single-point calculations at the CCSD(T) level were carried out at the optimized geometries. The rate constants have been calculated using the conventional transition-state theory (CTST). Arrhenius equations are proposed in the temperature range of 250-650 K. Hindered Internal Rotation partition functions calculations were explicitly carried out and included in the total partition functions. These corrections showed to be relevant in the determination of the pre-exponential parameters, although not so important as in the NO 3 + alkane reactions [G. Bravo-Perez, J.R. Alvarez-Idaboy, A. Cruz-Torres, M.E. Ruiz, J. Phys. Chem. A 106 (2002) 4645]. The explicit participation of the tunnel effect has been taken into account. The calculated rate coefficients provide a very good agreement with the experimental data. The best agreement for the overall alkane + OH reactions seemed to occur when the BHandHLYP geometries and partition functions are used. For propane and i-butane, in addition to the respective secondary and tertiary H-abstraction channels, the primary one has been considered. These pathways are confirmed to be significant in spite of the large differences in activation energies between primary and secondary or primary and tertiary channels, respectively of propane and i-butane reactions and should not be disregarded
He, Jing; Su, Derong; Lv, Shihai; Diao, Zhaoyan; Xie, Jingjie; Luo, Yan
2017-11-22
Rising temperature causes a process of phosphorus release, which can be characterized well using phosphorus release rates (V P ). The objective of the present study was to investigate the major factors affecting sediment phosphorus release rates through a wetland habitat simulation experiment. The results showed that the V P of different wetland sediments were different and changed with the order of W-R (river wetland) > W-L (lake wetland) > W-M (grassy marsh wetland) > W-A (reservoir wetland). The main driving factors which influenced sediment phosphorus flux velocity in the sediment-water interface were sediment B-SO₄ 2- , B-MBN and A-MBP content. Path analysis and determination coefficient analysis indicated the standard multiple regression equation for sediment phosphorus release rates in the sediment-water interface, and each main factor was Y = -0.105 + 0.096X₁ + 0.275X₂ - 0.010X₃ ( r = 0.416, p phosphorus release rates; X₁ is sediment B-SO₄ 2- content; X₂ is sediment B-MBN; and X₃ is sediment A-MBP content. Sediment B-SO₄ 2- , B-MBN and A-MBP content and the interaction between them were the main factors affecting sediment phosphorus release rates in the sediment-water interface. Therefore, these results suggest that soil chemical properties and microbial activities likely play an important role in phosphorus release rates in the sediment-water interface. We hope to provide effective scientific management and control methods for relevant environmental protection departments.
Directory of Open Access Journals (Sweden)
Jing He
2017-11-01
Full Text Available Rising temperature causes a process of phosphorus release, which can be characterized well using phosphorus release rates (VP. The objective of the present study was to investigate the major factors affecting sediment phosphorus release rates through a wetland habitat simulation experiment. The results showed that the VP of different wetland sediments were different and changed with the order of W–R (river wetland > W–L (lake wetland > W–M (grassy marsh wetland > W–A (reservoir wetland. The main driving factors which influenced sediment phosphorus flux velocity in the sediment–water interface were sediment B-SO42−, B-MBN and A-MBP content. Path analysis and determination coefficient analysis indicated the standard multiple regression equation for sediment phosphorus release rates in the sediment–water interface, and each main factor was Y = −0.105 + 0.096X1 + 0.275X2 − 0.010X3 (r = 0.416, p < 0.01, n = 144, where Y is sediment phosphorus release rates; X1 is sediment B-SO42− content; X2 is sediment B-MBN; and X3 is sediment A-MBP content. Sediment B-SO42−, B-MBN and A-MBP content and the interaction between them were the main factors affecting sediment phosphorus release rates in the sediment–water interface. Therefore, these results suggest that soil chemical properties and microbial activities likely play an important role in phosphorus release rates in the sediment–water interface. We hope to provide effective scientific management and control methods for relevant environmental protection departments.
Calculation of the effective environmental dose rate for ESR and luminescence dating
International Nuclear Information System (INIS)
Brennan, B.J.
2001-01-01
The determination of the age of a sample using luminescence and ESR dating techniques requires knowledge of the sample's average effective environmental dose rate due to natural radiation sources (alpha, beta, gamma, and cosmic), and age estimates can never be more accurate than the estimate of this dose rate. The estimation process is often complicated by spatial and temporal inhomogeneities in the distribution of natural radiation sources. This paper discusses applications of radiation physics in modelling the effects of these inhomogeneities to ensure accurate estimation of the average dose rate for the sample. For natural alpha, beta, and gamma sources, 'dose point kernels' are employed in calculations using an assumed model for the spatial and temporal dependence of source concentrations. These three types of radiation have rather different penetration properties, with their typical effective ranges being multiples of 10 micrometre, 1 mm, and 100 mm respectively. For each type of radiation, applications are discussed where spatial inhomogeneity in the distribution of sources around and in a sample has a serious effect on the average dose rate to the sample. In some cases, (e.g. gamma dose estimation in 'lumpy' environments) lack of detailed knowledge precludes accurate modelling of the site for a particular sample, but useful statistical information can still be obtained. Temporal variation of radioactive source concentrations is usually coupled with spatial effects and can arise from processes such as parent-daughter disequilibrium, uptake or leaching of sources, or variation in burial depth or water saturation. Again, calculations based non a known or assumed history can be employed to obtain a time-averaged dose rate for a sample. The accuracy with which these calculations can reflect the true environmental dose rate is limited principally by the reliability of the model assumed, which in turn depends on the state of knowledge of the site and its history
Calculating the dim light melatonin onset: the impact of threshold and sampling rate.
Molina, Thomas A; Burgess, Helen J
2011-10-01
The dim light melatonin onset (DLMO) is the most reliable circadian phase marker in humans, but the cost of assaying samples is relatively high. Therefore, the authors examined differences between DLMOs calculated from hourly versus half-hourly sampling and differences between DLMOs calculated with two recommended thresholds (a fixed threshold of 3 pg/mL and a variable "3k" threshold equal to the mean plus two standard deviations of the first three low daytime points). The authors calculated these DLMOs from salivary dim light melatonin profiles collected from 122 individuals (64 women) at baseline. DLMOs derived from hourly sampling occurred on average only 6-8 min earlier than the DLMOs derived from half-hourly saliva sampling, and they were highly correlated with each other (r ≥ 0.89, p 30 min from the DLMO derived from half-hourly sampling. The 3 pg/mL threshold produced significantly less variable DLMOs than the 3k threshold. However, the 3k threshold was significantly lower than the 3 pg/mL threshold (p < .001). The DLMOs calculated with the 3k method were significantly earlier (by 22-24 min) than the DLMOs calculated with the 3 pg/mL threshold, regardless of sampling rate. These results suggest that in large research studies and clinical settings, the more affordable and practical option of hourly sampling is adequate for a reasonable estimate of circadian phase. Although the 3 pg/mL fixed threshold is less variable than the 3k threshold, it produces estimates of the DLMO that are further from the initial rise of melatonin.
Verification of the calculation program for brachytherapy planning system of high dose rate (PLATO)
International Nuclear Information System (INIS)
Almansa, J.; Alaman, C.; Perez-Alija, J.; Herrero, C.; Real, R. del; Ososrio, J. L.
2011-01-01
In our treatments are performed brachytherapy high dose rate since 2007. The procedures performed include gynecological intracavitary treatment and interstitial. The treatments are performed with a source of Ir-192 activity between 5 and 10 Ci such that small variations in treatment times can cause damage to the patient. In addition the Royal Decree 1566/1998 on Quality Criteria in radiotherapy establishes the need to verify the monitor units or treatment time in radiotherapy and brachytherapy. All this justifies the existence of a redundant system for brachytherapy dose calculation that can reveal any abnormality is present.
Comparison of calculated and measured soil-gas radon concentration and radon exhalation rate
International Nuclear Information System (INIS)
Neznal, Martin; Neznal, Matej; Jiranek, Martin
2000-01-01
The computer model RADON2D for WINDOWS, which makes it possible to estimate the radon exhalation rate from the ground surface and the distribution of soil-gas radon concentration, was tested using a large set of experimental data coming from four reference areas located in regions with different geological structure. A good agreement between calculated and experimental data was observed. In the majority of cases, a correct description of the real situation was obtained using non-modified experimental input data. (author)
Preliminary Calculations of Shutdown Dose Rate for the CTS Diagnostics System
DEFF Research Database (Denmark)
Klinkby, Esben Bryndt; Nonbøl, Erik; Lauritzen, Bent
2015-01-01
DTU and IST 2 are partners in the design of a collective Thomson Scattering (CTS) diagnostics for ITER through a contract with F4E. The CTS diagnostic utilizes probing radiation of ~60 GHz emitted into the plasma and, using a mirror, collects the scattered radiation by an array of receivers. Having...... on supplying input which affect the system design. Examples include: - Heatloads on plasma facing mirrors and preliminary stress and thermal analysis - Port plug cooling requirements and it's dependence on system design (in particular blanket cut-out) - Shutdown dose-rate calculations (relative analysis...
Approximate techniques for calculating gamma ray dose rates in nuclear power plants
International Nuclear Information System (INIS)
Lahti, G.P.
1986-01-01
Although today's computers have made three-dimensional discrete ordinates transport codes a virtual reality, there is still a need for approximate techniques for estimating radiation environments. This paper discusses techniques for calculating gamma ray dose rates in nuclear power plants where Compton scattering is the dominant attenuation mechanism. The buildup factor method is reviewed; its use and misuse are discussed. Several useful rules-of-thumb are developed. The paper emphasizes the need for understanding the fundamental physics and draws heavily on the old, classic references
The Influence of Polyethylene Glycol Solution on the Dissolution Rate of Sustained Release Morphine.
Hodgman, Michael; Holland, Michael G; Englich, Ulrich; Wojcik, Susan M; Grant, William D; Leitner, Erich
2016-12-01
Whole bowel irrigation (WBI) is a management option for overdose of medications poorly adsorbed to activated charcoal, with modified release properties, or for body packers. Polyethylene glycol (PEG) is a mixture of ethylene oxide polymers of varying molecular weight. PEG with an average molecular weight of 3350 g/mol is used for WBI. PEG electrolyte lavage solution has been shown in vitro to hasten the dissolution of acetaminophen. The impact of PEG on the pharmacokinetics of extended release pharmaceuticals is unknown. Lower average molecular weight PEG mixtures are used as solvents and excipients. We sought to investigate the impact of PEG on the release of morphine from several extended release morphine formulations. An in vitro gastric model was developed. To test the validity of our model, we first investigated the previously described interaction of ethanol and Avinza®. Once demonstrated, we then investigated the effect of PEG with several extended release morphine formulations. In the validation portion of our study, we confirmed an ethanol Avinza® interaction. Subsequently, we did not observe accelerated release of morphine from Avinza® or generic extended release morphine in the presence of PEG. The use of PEG for gastric decontamination following ingestion of these extended release morphine formulations is unlikely to accelerate morphine release and aggravate intoxication.
Accurate Bit Error Rate Calculation for Asynchronous Chaos-Based DS-CDMA over Multipath Channel
Kaddoum, Georges; Roviras, Daniel; Chargé, Pascal; Fournier-Prunaret, Daniele
2009-12-01
An accurate approach to compute the bit error rate expression for multiuser chaosbased DS-CDMA system is presented in this paper. For more realistic communication system a slow fading multipath channel is considered. A simple RAKE receiver structure is considered. Based on the bit energy distribution, this approach compared to others computation methods existing in literature gives accurate results with low computation charge. Perfect estimation of the channel coefficients with the associated delays and chaos synchronization is assumed. The bit error rate is derived in terms of the bit energy distribution, the number of paths, the noise variance, and the number of users. Results are illustrated by theoretical calculations and numerical simulations which point out the accuracy of our approach.
Calculation of Rates of 4p–4d Transitions in Ar II
Directory of Open Access Journals (Sweden)
Alan Hibbert
2017-02-01
Full Text Available Recent experimental work by Belmonte et al. (2014 has given rates for some 4p–4d transitions that are significantly at variance with the previous experimental work of Rudko and Tang (1967 recommended in the NIST tabulations. To date, there are no theoretical rates with which to compare. In this work, we provide such theoretical data. We have undertaken a substantial and systematic configuration interaction calculation, with an extrapolation process applied to ab initio mixing coefficients, which gives energy differences in agreement with experiment. The length and velocity forms give values that are within 10%–15% of each other. Our results are in sufficiently close agreement with those of Belmonte et al. that we can confidently recommend that their results are much more accurate than the early results of Rudko and Tang, and should be adopted in place of the latter.
International Nuclear Information System (INIS)
Kawai, E; Umeno, Y
2017-01-01
As weight reduction of turbines for aircraft engines is demanded to improve fuel consumption and curb emission of carbon dioxide, silicon carbide (SiC) fiber reinforced SiC matrix composites (SiC/SiC) are drawing enormous attention as high-pressure turbine materials. For preventing degradation of SiC/SiC, environmental barrier coatings (EBC) for ceramics are deposited on the composites. The purpose of this study is to establish theoretical guidelines for structural design which ensures the mechanical reliability of EBC. We conducted finite element method (FEM) analysis to calculate energy release rates (ERRs) for interface crack initiation due to thermal stress in EBC consisting of Si-based bond coat, Mullite and Ytterbium (Yb)-silicate layers on a SiC/SiC substrate. In the FEM analysis, the thickness of one EBC layer was changed from 25 μm to 200 μm while the thicknesses of the other layers were fixed at 25 μm, 50 μm and 100 μm. We compared ERRs obtained by the FEM analysis and a simple theory for interface crack in a single-layered structure where ERR is estimated as nominal strain energy in the coating layers multiplied by a constant factor (independent of layer thicknesses). We found that, unlike the case of single-layered structures, the multiplication factor is no longer a constant but is determined by the combination of consisting coating layer thicknesses. (paper)
Kawai, E.; Umeno, Y.
2017-05-01
As weight reduction of turbines for aircraft engines is demanded to improve fuel consumption and curb emission of carbon dioxide, silicon carbide (SiC) fiber reinforced SiC matrix composites (SiC/SiC) are drawing enormous attention as high-pressure turbine materials. For preventing degradation of SiC/SiC, environmental barrier coatings (EBC) for ceramics are deposited on the composites. The purpose of this study is to establish theoretical guidelines for structural design which ensures the mechanical reliability of EBC. We conducted finite element method (FEM) analysis to calculate energy release rates (ERRs) for interface crack initiation due to thermal stress in EBC consisting of Si-based bond coat, Mullite and Ytterbium (Yb)-silicate layers on a SiC/SiC substrate. In the FEM analysis, the thickness of one EBC layer was changed from 25 μm to 200 μm while the thicknesses of the other layers were fixed at 25 μm, 50 μm and 100 μm. We compared ERRs obtained by the FEM analysis and a simple theory for interface crack in a single-layered structure where ERR is estimated as nominal strain energy in the coating layers multiplied by a constant factor (independent of layer thicknesses). We found that, unlike the case of single-layered structures, the multiplication factor is no longer a constant but is determined by the combination of consisting coating layer thicknesses.
Samshuri, S. F.; Daud, R.; Rojan, M. A.; Mat, F.; Basaruddin, K. S.; Hassan, R.
2017-10-01
This paper presents the energy method to evaluate fracture behavior of enamel-cement-bracket system based on cement thickness. Finite element (FE) model of enamel-cement-bracket was constructed by using ANSYS Parametric Design Language (APDL). Three different thickness were used in this study, 0.05, 0.2, and 0.271 mm which assigned as thin, medium and thick for both enamel-cement and cement bracket interface cracks. Virtual crack closure technique (VCCT) was implemented as a simulation method to calculated energy release rate (ERR). Simulation results were obtained for each thickness are discussed by using Griffith’s energy balance approach. ERR for thin thickness are found to be the lowest compared to medium and thick. Peak value of ERR also showed a significant different between medium and thick thickness. Therefore, weakest bonding occurred at low cement thickness because less load required to produce enough energy to detach the bracket. For medium and thick thickness, both increased rapidly in energy value at about the mid-point of the enamel-cement interface. This behavior occurred because of the increasing in mechanical and surface energy when the cracks are increasing. However, result for thick thickness are higher at mid-point compared to thin thickness. In conclusion, fracture behavior of enamel cracking process for medium most likely the safest to avoid enamel fracture and withstand bracket debonding.
A comparison of reaction rate calculations using Endf/B-VII with critical assembly measurements
International Nuclear Information System (INIS)
Wilkerson, C.; Mac Innes, M.; Barr, D.; Trellue, H.; MacFarlane, R.; Chadwick, M.
2008-01-01
We present critical assembly reaction rate data, and modeling of the same using the recently released Endf/B-VII library. While some of the experimental measurements were performed as long as 50 years ago, the results have not been widely used/available outside of Los Alamos. Over the years, a variety of target foils were fabricated and placed in differing neutron spectrum/fluence environments within critical assemblies. Neutron-induced reactions such as (n,γ), (n,2n), and (n,f) on these targets were measured, typically referenced to 235 U(n,f) or 239 Pu(n,f). Because the cross section for the latter reactions are now well known, these experiments provide a rich data set for testing evaluated cross sections. Due to the large variety of critical assemblies that were historically available at Los Alamos, it was possible to make measurements in spectral environments ranging from hard (Pu Jezebel, center of Pu Flattop) through intermediate (Big Ten) to degraded (reflector region of Flattop). This broad range of configurations allows us to test both the cross section magnitudes and their energy dependencies. We will present data, along with reaction rate predictions using primarily MCNP5 in conjunction with Endf/B-VII, for a number of target nuclei, including iridium, isotopes of uranium (e.g., 233, 235, 237, 238), neptunium (237), plutonium (239), and americium (241). (authors)
Magma addition rates in continental arcs: New methods of calculation and global implications
Ratschbacher, B. C.; Paterson, S. R.
2017-12-01
The transport of mass, heat and geochemical constituents (elements and volatiles) from the mantle to the atmosphere occurs via magma addition to the lithosphere. Calculation of magma addition rates (MARs) in continental arcs based on exposed proportions of igneous arc rocks is complex and rarely consistently determined. Multiple factors influence MAR calculations such as crust versus mantle contributions to magmas, a change in MARs across the arc and with depths throughout the arc crustal column, `arc tempos' with periods of high and low magmatic activity, the loss of previous emplaced arc rocks by subsequent magmatism and return to the mantle, arc migration, variations in the intrusive versus extrusive additions and evolving arc widths and thicknesses during tectonism. All of these factors need to be considered when calculating MARs.This study makes a new attempt to calculate MARs in continental arcs by studying three arc sections: the Famatinian arc, Argentina, the Sierra Nevada batholith, California and the Coast Mountain batholith, Washington and British Columbia. Arcs are divided into fore-arc, main arc and back arc sections and `boxes' with a defined width, length and thickness spanning upper middle and lower crustal levels are assigned to each section. Representative exposed crustal slices for each depth are then used to calculate MARs based on outcrop proportions for each box. Geochemical data is used to infer crustal recycling percentages and total thickness of the arc. Preliminary results show a correlation between MARs, crustal thicknesses and magmatic flare-up durations. For instance, the Famatinian arc shows a strong decrease in MARs between the main arc section (9.4 km3/Ma/arc-km) and the fore-arc (0.61 km3/Ma/arc-km) and back-arc (1.52 km3/Ma/arc-km) regions and an increase in the amount of magmatism with depth.Global MARs over geologic timescales have the potential to investigate mantle melt generation rates and the volatile outgassing contribution
Direct calculation of ice homogeneous nucleation rate for a molecular model of water
Haji-Akbari, Amir; Debenedetti, Pablo G.
2015-01-01
Ice formation is ubiquitous in nature, with important consequences in a variety of environments, including biological cells, soil, aircraft, transportation infrastructure, and atmospheric clouds. However, its intrinsic kinetics and microscopic mechanism are difficult to discern with current experiments. Molecular simulations of ice nucleation are also challenging, and direct rate calculations have only been performed for coarse-grained models of water. For molecular models, only indirect estimates have been obtained, e.g., by assuming the validity of classical nucleation theory. We use a path sampling approach to perform, to our knowledge, the first direct rate calculation of homogeneous nucleation of ice in a molecular model of water. We use TIP4P/Ice, the most accurate among existing molecular models for studying ice polymorphs. By using a novel topological approach to distinguish different polymorphs, we are able to identify a freezing mechanism that involves a competition between cubic and hexagonal ice in the early stages of nucleation. In this competition, the cubic polymorph takes over because the addition of new topological structural motifs consistent with cubic ice leads to the formation of more compact crystallites. This is not true for topological hexagonal motifs, which give rise to elongated crystallites that are not able to grow. This leads to transition states that are rich in cubic ice, and not the thermodynamically stable hexagonal polymorph. This mechanism provides a molecular explanation for the earlier experimental and computational observations of the preference for cubic ice in the literature. PMID:26240318
Heart rate calculation from ensemble brain wave using wavelet and Teager-Kaiser energy operator.
Srinivasan, Jayaraman; Adithya, V
2015-01-01
Electroencephalogram (EEG) signal artifacts are caused by various factors, such as, Electro-oculogram (EOG), Electromyogram (EMG), Electrocardiogram (ECG), movement artifact and line interference. The relatively high electrical energy cardiac activity causes EEG artifacts. In EEG signal processing the general approach is to remove the ECG signal. In this paper, we introduce an automated method to extract the ECG signal from EEG using wavelet and Teager-Kaiser energy operator for R-peak enhancement and detection. From the detected R-peaks the heart rate (HR) is calculated for clinical diagnosis. To check the efficiency of our method, we compare the HR calculated from ECG signal recorded in synchronous with EEG. The proposed method yields a mean error of 1.4% for the heart rate and 1.7% for mean R-R interval. The result illustrates that, proposed method can be used for ECG extraction from single channel EEG and used in clinical diagnosis like estimation for stress analysis, fatigue, and sleep stages classification studies as a multi-model system. In addition, this method eliminates the dependence of additional synchronous ECG in extraction of ECG from EEG signal process.
Verification of the LWRARC code for light-water-reactor afterheat rate calculations
International Nuclear Information System (INIS)
Murphy, B.D.
1998-02-01
This report describes verification studies carried out on the LWRARC (Light-Water-Reactor Afterheat Rate Calculations) computer code. The LWRARC code is proposed for automating the implementation of procedures specified in Draft Revision 1 of the U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide 3.54, open-quotes Spent-Fuel Heat Generation in an Independent Spent-Fuel Storage Installation,close quotes which gives guidelines on the calculation of decay heat for spent nuclear fuel. Draft Regulatory Guide 3.54 allows one to estimate decay-heat values by means of a table lookup procedure with interpolation performed between table-entry values. The tabulated values of the relevant parameters span ranges that are appropriate for spent fuel from a boiling-water reactor (BWR) or a pressurized-water reactor (PWR), as the case may be, and decay-heat rates are obtained for spent fuel whose properties are within those parameter limits. In some instances, where these limits are either exceeded or where they approach critical regions, adjustments are invoked following table lookup. The LWRARC computer code is intended to replicate the manual process just described. In the code, the table lookup is done by entering a database and carrying out interpolations. The code then determines if adjustments apply, and, if this is the case, adjustment factors are calculated separately. The manual procedures in the Draft Regulatory Guide have been validated (i.e., they produce results that are good estimates of reality). The work reported in this document verifies that the LWRARC code replicates the manual procedures of the Draft Regulatory Guide, and that the code, taken together with the Draft Regulatory Guide, can support both verification and validation processes
ESTIMATION OF FLEXIBILITY OF AN ORGANIZATION ON THE GROUND OF THE CALCULATION OF PROFIT MARGIN RATE
Directory of Open Access Journals (Sweden)
Olga Gennadevna Rybakova
2016-12-01
Full Text Available The article deals with the problem of the flexibility of an organization as the ability to adapt effectively to the external environment. The authors have identified and investigated different approaches to estimating the flexibility of an organization on the ground of flexibility grading, calculation of the general index of flexibility as well as the calculation of flexibility’s ranking score. We have identified the advantages and disadvantages of these approaches. A new method of the estimation of an organization’s flexibility on the ground of the calculation of relative profit margin has been developed. This method is the multifunctional assessment tool of enterprise’s functionability in the current context of difficult and volatile economic environment. It allows in the early stage to identify negative trends in the production and financial figures and thus, it enables the organizational leadership to take steps in advance in order to avert a crisis in its activity. Keeping the profit margin at the same rate at the forced contraction of output, because of the negative impact of external factors, will confirm that the organization has adapted to the external environment and, therefore, it is flexible. The organization can be considered with margin rate beginning to low up to zero value as an organization with an insufficient level of flexibility that is at the “zone of crisis” and it is characterized by the depletion of reserved funds and reduction of current assets. Loss-maker is nonflexible and the presence of loss means that the organization has an evident sign of crisis and it can be bankrupt.
A simple algebraic cancer equation: calculating how cancers may arise with normal mutation rates
Directory of Open Access Journals (Sweden)
Shibata Darryl
2010-01-01
Full Text Available Abstract Background The purpose of this article is to present a relatively easy to understand cancer model where transformation occurs when the first cell, among many at risk within a colon, accumulates a set of driver mutations. The analysis of this model yields a simple algebraic equation, which takes as inputs the number of stem cells, mutation and division rates, and the number of driver mutations, and makes predictions about cancer epidemiology. Methods The equation [p = 1 - (1 - (1 - (1 - udkNm ] calculates the probability of cancer (p and contains five parameters: the number of divisions (d, the number of stem cells (N × m, the number of critical rate-limiting pathway driver mutations (k, and the mutation rate (u. In this model progression to cancer "starts" at conception and mutations accumulate with cell division. Transformation occurs when a critical number of rate-limiting pathway mutations first accumulates within a single stem cell. Results When applied to several colorectal cancer data sets, parameter values consistent with crypt stem cell biology and normal mutation rates were able to match the increase in cancer with aging, and the mutation frequencies found in cancer genomes. The equation can help explain how cancer risks may vary with age, height, germline mutations, and aspirin use. APC mutations may shorten pathways to cancer by effectively increasing the numbers of stem cells at risk. Conclusions The equation illustrates that age-related increases in cancer frequencies may result from relatively normal division and mutation rates. Although this equation does not encompass all of the known complexity of cancer, it may be useful, especially in a teaching setting, to help illustrate relationships between small and large cancer features.
Dose Rate Experiment at JET for Benchmarking the Calculation Direct One Step Method
International Nuclear Information System (INIS)
Angelone, M.; Petrizzi, L.; Pillon, M.; Villari, R.; Popovichev, S.
2006-01-01
, experimental background data and dose rate, the latter collected during some operation free days in the early phase of the 2006 JET campaign, are compared with the same quantities calculated using the D1S approach. The impact of key parameters (geometrical model, materials impurities, different sets of cross sections) to the calculated dose rates is discussed as well. (author)
International Nuclear Information System (INIS)
Carny, P.; Suchon, D.; Smejkalova, E.; Fabova, V.
2009-01-01
ESTE AI is a program for calculation of radiation doses caused by effluents in routine releases to the atmosphere and to the hydrosphere. Doses to the members of critical groups of inhabitants in the vicinity of NPP are calculated and as a result, critical group is determined. The program enables to calculate collective doses as well. Collective doses to the inhabitants living in the vicinity of the NPP are calculated. ESTE AI calculates doses to the whole population of Slovakia from the effluents of the specific plant. In this calculation, global nuclides are included and assumed, as well. The program enables to calculate and to document beyond-border radiological impacts of effluents caused by routine operation of NPP. ESTE AI was approved by the 'Public Health Authority of the Slovak Republic' and is used as legal instrument by Slovenske elektrarne a.s., NPP Bohunice. (authors)
International Nuclear Information System (INIS)
Carny, P.; Suchon, D.; Smejkalova, E.; Fabova, V.
2008-01-01
ESTE AI is a program for calculation of radiation doses caused by effluents in routine releases to the atmosphere and to the hydrosphere. Doses to the members of critical groups of inhabitants in the vicinity of NPP are calculated and as a result, critical group is determined. The program enables to calculate collective doses as well. Collective doses to the inhabitants living in the vicinity of the NPP are calculated. ESTE AI calculates doses to the whole population of Slovakia from the effluents of the specific plant. In this calculation, global nuclides are included and assumed, as well. The program enables to calculate and to document beyond-border radiological impacts of effluents caused by routine operation of NPP. ESTE AI was approved by the 'Public Health Authority of the Slovak Republic' and is used as legal instrument by Slovenske elektrarne a.s., NPP Bohunice. (authors)
International Nuclear Information System (INIS)
Cruz L, C. A.
2015-01-01
In the present thesis, the software DERA (Dispersion of Radioactive Effluents into the Atmosphere) was developed in order to calculate the equivalent dose, external and internal, associated with the release of radioactive effluents into the atmosphere from a nuclear facility. The software describes such emissions in normal operation, and not considering the exceptional situations such as accidents. Several tools were integrated for describing the dispersion of radioactive effluents using site meteorological information (average speed and wind direction and the stability profile). Starting with the calculation of the concentration of the effluent as a function of position, DERA estimates equivalent doses using a set of EPA s and ICRP s coefficients. The software contains a module that integrates a database with these coefficients for a set of 825 different radioisotopes and uses the Gaussian method to calculate the effluents dispersion. This work analyzes how adequate is the Gaussian model to describe emissions type -puff-. Chapter 4 concludes, on the basis of a comparison of the recommended correlations of emissions type -puff-, that under certain conditions (in particular with intermittent emissions) it is possible to perform an adequate description using the Gaussian model. The dispersion coefficients (σ y and σ z ), that using the Gaussian model, were obtained from different correlations given in the literature. Also in Chapter 5 is presented the construction of a particular correlation using Lagrange polynomials, which takes information from the Pasquill-Gifford-Turner curves (PGT). This work also contains a state of the art about the coefficients that relate the concentration with the equivalent dose. This topic is discussed in Chapter 6, including a brief description of the biological-compartmental models developed by the ICRP. The software s development was performed using the programming language Python 2.7, for the Windows operating system (the XP
Directory of Open Access Journals (Sweden)
Majid Saeedi
2015-01-01
Full Text Available Polysaccharide mucilage derived from the seeds of Ocimum basilicum L. (family Lamiaceae was investigated for use in matrix formulations containing propranolol hydrochloride. Basil mucilage was extracted and several tablets were formulated. The effect of mucilage on drug release rate was evaluated in comparison with tablets containing two kinds of hydroxypropyl methylcellulose (HPMC K4M and HPMC K100M as standard polymer. The release data were fitted to several models for kinetic evaluation. The results showed that hardness decreased and friability of tablets increased as the concentration of mucilage increased. The rate of release of propranolol HCl from O. basilicm mucilage matrices was mainly controlled by the drug: mucilage ratio. Drug release was slower from the HPMC K4M and HPMCK100M containing tablets compared to the mucilage containing matrices than the drug release from matrices containing O. basilicum seed mucilage in similar ratios. Formulations containing O. basilicm mucilage were found to exhibit suitable release pattern. The results of kinetic analysis showed that in tablets containing O. basilicm mucilage the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that, as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets.
International Nuclear Information System (INIS)
Jacobs, D.G.; Easterly, C.E.; Phillips, J.E.
1979-01-01
Releases of tritium in the past have been largely in the form of tritiated water, and the projected radiation doses could be estimated by assuming tritium behaviour to parallel that of water. There is increasing interest in potential releases of tritium in the form of HT because of significant recent advances in fusion reactor research. Several recent studies have shown that bacteria containing the enzyme hydrogenase can catalyse the conversion of HT to HTO at rates several orders of magnitude faster than the rates measured in atmospheric systems. Rates of conversion in the soil have been combined with estimates of rates of permeation of HT into the soil and with global and local models depicting tritium transport and cycling. The results suggest that for the expected conversion rates, the impact on projected radiation doses should be relatively minor. (author)
Review of tellurium release rates from LWR fuel elements under accident conditions
International Nuclear Information System (INIS)
Lorenz, R.A.; Beahm, E.C.; Wichner, R.P.
1983-01-01
Although fission product tellurium presents a potentially significant radiohazard, its release and transport in source-term experiments is frequently overlooked because it does not possess a readily measurable, gamma emission; moreover, a recent study emphasized noble gas, iodine and cesium release from LWR fuel elements because of the large data base that exists for these materials. Some new tests show that in some cases tellurium may be held up in core material to a greater degree than previously assumed - an observation that prompts a careful reappraisal of the existing tellurium-release data and its chemical foundation
Forward flux sampling calculation of homogeneous nucleation rates from aqueous NaCl solutions.
Jiang, Hao; Haji-Akbari, Amir; Debenedetti, Pablo G; Panagiotopoulos, Athanassios Z
2018-01-28
We used molecular dynamics simulations and the path sampling technique known as forward flux sampling to study homogeneous nucleation of NaCl crystals from supersaturated aqueous solutions at 298 K and 1 bar. Nucleation rates were obtained for a range of salt concentrations for the Joung-Cheatham NaCl force field combined with the Extended Simple Point Charge (SPC/E) water model. The calculated nucleation rates are significantly lower than the available experimental measurements. The estimates for the nucleation rates in this work do not rely on classical nucleation theory, but the pathways observed in the simulations suggest that the nucleation process is better described by classical nucleation theory than an alternative interpretation based on Ostwald's step rule, in contrast to some prior simulations of related models. In addition to the size of NaCl nucleus, we find that the crystallinity of a nascent cluster plays an important role in the nucleation process. Nuclei with high crystallinity were found to have higher growth probability and longer lifetimes, possibly because they are less exposed to hydration water.
Directory of Open Access Journals (Sweden)
Adam M. Gonzalez, Jay R. Hoffman, Adam J. Wells, Gerald T. Mangine, Jeremy R. Townsend, Adam R. Jajtner, Ran Wang, Amelia A. Miramonti, Gabriel J. Pruna, Michael B. LaMonica, Jonathan D. Bohner, Mattan W. Hoffman, Leonardo P. Oliveira, David H. Fukuda, Maren S. Fragala, Jeffrey R. Stout
2015-06-01
Full Text Available This study compared caffeine pharmacokinetics, glycerol concentrations, metabolic rate, and performance measures following ingestion of a time-release caffeine containing supplement (TR-CAF versus a regular caffeine capsule (CAF and a placebo (PL. Following a double-blind, placebo-controlled, randomized, cross-over design, ten males (25.9 ± 3.2 y who regularly consume caffeine ingested capsules containing either TR-CAF, CAF, or PL. Blood draws and performance measures occurred at every hour over an 8-hour period. Plasma caffeine concentrations were significantly greater (p < 0.05 in CAF compared to TR-CAF during hours 2-5 and significantly greater (p = 0.042 in TR-CAF compared to CAF at hour 8. There were no significant differences between trials in glycerol concentrations (p = 0.86 or metabolic measures (p = 0.17-0.91. Physical reaction time was significantly improved for CAF at hour 5 (p=0.01 compared to PL. Average upper body reaction time was significantly improved for CAF and TR-CAF during hours 1-4 (p = 0.04 and p = 0.01, respectively and over the 8-hour period (p = 0.04 and p = 0.001, respectively compared to PL. Average upper body reaction time was also significantly improved for TR-CAF compared to PL during hours 5-8 (p = 0.004. TR-CAF and CAF showed distinct pharmacokinetics yielding modest effects on reaction time, yet did not alter glycerol concentration, metabolic measures, or other performance measures.
Lee, Tae Geol; Park, Seung C.; Kim, Myung Soo
1996-03-01
Mass-analyzed ion kinetic energy (MIKE) spectrum of CHO+ generated in the unimolecular dissociation of CH2OH+ was measured. Kinetic energy release distribution (KERD) was evaluated by analyzing the spectrum according to the algorithm developed previously. The average kinetic energy release evaluated from the distribution was extraordinarily large, 1.63 eV, corresponding to 75% of the reverse barrier of the reaction. A global analytical potential energy surface was constructed such that the experimental energetics was represented and that various features in the ab initio potential energy surface were closely reproduced. Classical trajectory calculation was carried out with the global analytical potential energy surface to investigate the causes for the extraordinarily large kinetic energy release. Based on the detailed dynamical calculations, it was found that the strained bending forces at the transition state and strengthening of the CO bond from double to triple bond character were mainly responsible for such a significant kinetic energy release. In addition, the dissociation products H2 and CHO+ ion were found to be rotationally excited in the trajectory calculations. This was attributed to the asymmetry of the transition state and the release of asymmetric bending forces. Also, the bending vibrational modes of CHO+ and the H2 stretching mode, which are coupled with the bending coordinates, were found to be moderately excited.
International Nuclear Information System (INIS)
Kaiser, G.D.
1976-11-01
A brief description is given of the contents of TIRION, which is a computer program that has been written for use in calculations of the consequences of releasing radioactive material to the atmosphere. This is followed by a section devoted to an account of the control and data cards that make up the input to TIRION. (author)
International Nuclear Information System (INIS)
SCOTT, D.L.
1999-01-01
To more fully characterize the vadose zone near Single Shell Tank 241-SX-115, another borehole will be drilled and sampled by using reverse circulation drilling equipment. Compressed air propels the drill and sweeps out cuttings. Dose calculations in this document are performed for an unmitigated airborne release from the drill string. Doses were found not to exceed TWRS risk guideline values
Implications of imprecision in kinetic rate data for photochemical model calculations
Energy Technology Data Exchange (ETDEWEB)
Stewart, R W; Thompson, A M [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
1998-12-31
Evaluation of uncertainties in photochemical model calculations is of great importance to scientists performing assessment modeling. A major source of uncertainty is the measurement imprecision inherent in photochemical reaction rate data that modelers rely on. A rigorous method of evaluating the impact of data imprecision on computational uncertainty is the study of error propagation using Monte Carlo techniques. There are two problems with the current implementation of the Monte Carlo method. First, there is no satisfactory way of accounting for the variation of imprecision with temperature in 1, 2, or 3D models; second, due to its computational expense, it is impractical in 3D model studies. These difficulties are discussed. (author) 4 refs.
Implications of imprecision in kinetic rate data for photochemical model calculations
Energy Technology Data Exchange (ETDEWEB)
Stewart, R.W.; Thompson, A.M. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
1997-12-31
Evaluation of uncertainties in photochemical model calculations is of great importance to scientists performing assessment modeling. A major source of uncertainty is the measurement imprecision inherent in photochemical reaction rate data that modelers rely on. A rigorous method of evaluating the impact of data imprecision on computational uncertainty is the study of error propagation using Monte Carlo techniques. There are two problems with the current implementation of the Monte Carlo method. First, there is no satisfactory way of accounting for the variation of imprecision with temperature in 1, 2, or 3D models; second, due to its computational expense, it is impractical in 3D model studies. These difficulties are discussed. (author) 4 refs.
International Nuclear Information System (INIS)
Boccaccini, L.V.
1986-07-01
To take advantages of the semi-implicit computer models - to solve the two phase flow differential system - a proper averaging procedure is also needed for the source terms. In fact, in some cases, the correlations normally used for the source terms - not time averaged - fail using the theoretical time step that arises from the linear stability analysis used on the right handside. Such a time averaging procedure is developed with reference to the bubbly flow regime. Moreover, the concept of mass that must be exchanged to reach equilibrium from a non-equilibrium state is introduced to limit the mass transfer during a time step. Finally some practical calculations are performed to compare the different correlations for the average mass transfer rate developed in this work. (orig.) [de
The simplified convergence rate calculation for salt grit backfilled caverns in rock salt
International Nuclear Information System (INIS)
Navarro, Martin
2013-03-01
Within the research and development project 3609R03210 of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, different methods were investigated, which are used for the simplified calculation of convergence rates for mining cavities in salt rock that have been backfilled with crushed salt. The work concentrates on the approach of Stelte and on further developments based on this approach. The work focuses on the physical background of the approaches. Model specific limitations are discussed and possibilities for further development are pointed out. Further on, an alternative approach is presented, which implements independent material laws for the convergence of the mining cavity and the compaction of the crushed salt backfill.
Systematic comparison of ISOLDE-SC yields with calculated in-target production rates
International Nuclear Information System (INIS)
Lukic, S.; Gevaert, F.; Kelic, A.; Ricciardi, M.V.; Schmidt, K.H.; Yordanov, O.
2006-02-01
Recently, a series of dedicated inverse-kinematics experiments performed at GSI, Darmstadt, has brought an important progress in our understanding of proton and heavy-ion induced reactions at relativistic energies. The nuclear reaction code ABRABLA that has been developed and benchmarked against the results of these experiments has been used to calculate nuclide production cross sections at different energies and with different targets and beams. These calculations are used to estimate nuclide production rates by protons in thick targets, taking into account the energy loss and the attenuation of the proton beam in the target, as well as the low-energy fission induced by the secondary neutrons. The results are compared to the yields of isotopes of various elements obtained from different targets at CERN-ISOLDE with 600 MeV protons, and the overall extraction efficiencies are deduced. The dependence of these extraction efficiencies on the nuclide half-life is found to follow a simple pattern in many different cases. A simple function is proposed to parameterize this behavior in a way that quantifies the essential properties of the extraction efficiency for the element and the target - ion-source system in question. (orig.)
Domènech, Guillem; Corominas, Jordi; Mavrouli, Olga; Merchel, Silke; Abellán, Antonio; Pavetich, Stefan; Rugel, Georg
2018-04-01
Cliff erosion may be a major problem in settled areas affecting populations and producing economic and ecological losses. In this paper we present a procedure to calculate the long-term retreat rate of a cliff affected by rockfalls in the Montsec Range, Eastern Pyrenees (Spain). It is composed of low, densely fractured limestones; and the rockwall is affected by rockfalls of different sizes. The rockfall scars are clearly distinguishable by their regular boundaries and by their orange colour, which contrast with the greyish old reference surface (S0) of the cliff face. We have dated different stepped surfaces of the rockwall, including S0, using cosmogenic 36Cl. The total amount of material released by rockfall activity was calculated using a high definition point cloud of the slope face obtained with a terrestrial laser scanner (TLS). The present rockwall surface has been subtracted from the reconstructed old cliff surface. This has allowed the calculation of the total volume released by rockfalls and of the retreat rate. The latter ranges from 0.31 to 0.37 mm·a- 1. This value is of the same order of magnitude as that obtained by other researchers in neighbouring regions in Spain, having similar geology and affected by rockfalls.
Development and evaluation of a new prototype P&T system to determine in-heading gas release rate.
CSIR Research Space (South Africa)
Van Zyl, FJ
2001-11-01
Full Text Available In order to quantify the potential methane hazard in underground coal mines, it is necessary to determine the in-seam methane content and an expected gas release rate during production. Various methods for estimating this have been proposed, ranging...
Ryosuke Fujinuma; Nick J. Balster; Hyung-Kyung. Lee
2011-01-01
Controlled-release fertilizer (CRF) typically increases nitrogen (N) fertilizer uptake and lowers N lost from the rooting zone via leaching. However, questions remain as to whether lower rates of CRF could further increase this efficiency, especially in sandy bare-root nurseries in Wisconsin. We hypothesized that: 1) a reduced CRF application at 60 percent of the...
Laura E. Hasburgh; Robert H. White; Mark A. Dietenberger; Charles R. Boardman
2015-01-01
There is a growing demand for material properties to be used as inputs in fi re behavior models designed to address building fire safety. This comparative study evaluates using the mass loss calorimeter as an alternative to the cone calorimeter for obtaining heat release rates of wood-based materials. For this study, a modified mass loss calorimeter utilized an...
Energy Technology Data Exchange (ETDEWEB)
Strenge, D L; Baker, D A; Droppo, J G; McPherson, R B; Napier, B A; Nieves, L A; Soldat, J K
1980-05-01
Models are described for use in site-specific environmental consequence analysis of nuclear reactor accidents of Classes 3 through 9. The models presented relate radioactivity released to resulting doses, health effects, and costs of remedial actions. Specific models are presented for the major exposure pathways of airborne releases, waterborne releases and direct irradiation from activity within the facility buildings, such as the containment. Time-dependent atmospheric dispersion parameters, crop production parameters and other variable parameters are used in the models. The environmental effects are analyzed for several accident start times during the year.
International Nuclear Information System (INIS)
Tachibana, Haruo; Kikuchi, Masamitsu; Sekita, Tsutomu; Yamaguchi, Takenori
2004-06-01
This report is a revised edition of 'Isopleths of Surface Air Concentration and Surface Air Absorbed Dose Rate due to a Radioactive Cloud Released from a Stack(II) '(JAERI-M 90-206) and based on the revised Nuclear Safety Guidelines reflected the ICRP1990 Recommendation. Characteristics of this report are the use of Air Karma Rate (Gy/h) instead of Air Absorbed Dose Rate (Gy/h), and the record of isopleths of surface air concentration and surface air karma rate on CD-ROM. These recorded data on CD-ROM can be printed out on paper and/or pasted on digital map by personal computer. (author)
Ariyoshi, Jumpei; Matsuyama, Yohei; Kobori, Akio; Murakami, Akira; Sugiyama, Hiroshi; Yamayoshi, Asako
2017-10-01
MicroRNAs (miRNAs) regulate gene expression by forming RNA-induced silencing complexes (RISCs) and have been considered as promising therapeutic targets. MiRNA is an essential component of RISC for the modulation of gene expression. Therefore, the release of miRNA from RISC is considered as an effective method for the inhibition of miRNA functions. In our previous study, we reported that anti-miRNA oligonucleotides (AMOs), which are composed of the 2'-O-methyl (2'-OMe) RNA, could induce the release of miRNA from RISC. However, the mechanisms underlying the miRNA-releasing effects of chemically modified AMOs, which are conventionally used as anti-cancer drugs, are still unclear. In this study, we investigated the relationship between the miRNA releasing rate from RISC and the inhibitory effect on RISC activity (IC 50 ) using conventional chemically modified AMOs. We demonstrated that the miRNA-releasing effects of AMOs are directly proportional to the IC 50 values, and AMOs, which have an ability to promote the release of miRNA from RISC, can effectively inhibit RISC activity in living cells.
van der Heijden, R T; Heijnen, J J; Hellinga, C; Romein, B; Luyben, K C
1994-01-05
Measurements provide the basis for process monitoring and control as well as for model development and validation. Systematic approaches to increase the accuracy and credibility of the empirical data set are therefore of great value. In (bio)chemical conversions, linear conservation relations such as the balance equations for charge, enthalpy, and/or chemical elements, can be employed to relate conversion rates. In a pactical situation, some of these rates will be measured (in effect, be calculated directly from primary measurements of, e.g., concentrations and flow rates), as others can or cannot be calculated from the measured ones. When certain measured rates can also be calculated from other measured rates, the set of equations, the accuracy and credibility of the measured rates can indeed be improved by, respectively, balancing and gross error diagnosis. The balanced conversion rates are more accurate, and form a consistent set of data, which is more suitable for further application (e.g., to calculate nonmeasured rates) than the raw measurements. Such an approach has drawn attention in previous studies. The current study deals mainly with the problem of mathematically classifying the conversion rates into balanceable and calculable rates, given the subset of measured rates. The significance of this problem is illustrated with some examples. It is shown that a simple matrix equation can be derived that contains the vector of measured conversion rates and the redundancy matrix R. Matrix R plays a predominant role in the classification problem. In supplementary articles, significance of the redundancy matrix R for an improved gross error diagnosis approach will be shown. In addition, efficient equations have been derived to calculate the balanceable and/or calculable rates. The method is completely based on matrix algebra (principally different from the graph-theoretical approach), and it is easily implemented into a computer program. (c) 1994 John Wiley & Sons
Sörgel, Matthias; Trebs, Ivonne; Wu, Dianming; Held, Andreas
2015-04-01
Vertical mixing ratio profiles of nitrous acid (HONO) were measured in a clearing and on the forest floor in a rural forest environment (in the south-east of Germany) by applying a lift system to move the sampling unit of the LOng Path Absorption Photometer (LOPAP) up and down. For the forest floor, HONO was found to be predominantly deposited, whereas net deposition was dominating in the clearing only during nighttime and net emissions were observed during daytime. For selected days, net fluxes of HONO were calculated from the measured profiles using the aerodynamic gradient method. The emission fluxes were in the range of 0.02 to 0.07 nmol m-2 s-1, and, thus were in the lower range of previous observations. These fluxes were compared to the strengths of postulated HONO sources and to the amount of HONO needed to sustain photolysis in the boundary layer. Laboratory measurements of different soil samples from both sites revealed an upper limit for soil biogenic HONO emission fluxes of 0.025 nmol m-2 s-1. HONO formation by light induced NO2 conversion was calculated to be below 0.03 nmol m-2 s-1 for the investigated days, which is comparable to the potential soil fluxes. Due to light saturation at low irradiance, this reaction pathway was largely found to be independent of light intensity, i.e. it was only dependent on ambient NO2. We used three different approaches based on measured leaf nitrate loadings for calculating HONO formation from HNO3 photolysis. While the first two approaches based on empirical HONO formation rates yielded values in the same order of magnitude as the estimated fluxes, the third approach based on available kinetic data of the postulated pathway failed to produce noticeable amounts of HONO. Estimates based on reported cross sections of adsorbed HNO3 indicate that the lifetime of adsorbed HNO3 was only about 15 min, which would imply a substantial renoxification. Although the photolysis of HNO3 was significantly enhanced at the surface, the
Energy Technology Data Exchange (ETDEWEB)
Hagendorfer, Harald, E-mail: Harald.Hagendorfer@empa.c [EMPA, Swiss Federal Laboratories for Materials Testing and Research (Switzerland); Lorenz, Christiane, E-mail: Christiane.Lorenz@chem.ethz.c [ETHZ, Swiss Federal Institute of Technology Zurich (Switzerland); Kaegi, Ralf, E-mail: Ralf.Kaegi@eawag.ch; Sinnet, Brian, E-mail: Brian.Sinnet@eawag.c [EAWAG, Swiss Federal Institute of Aquatic Science and Technology (Switzerland); Gehrig, Robert, E-mail: Robert.Gehrig@empa.c [EMPA, Swiss Federal Laboratories for Materials Testing and Research (Switzerland); Goetz, Natalie V., E-mail: Natalie.vonGoetz@chem.ethz.ch; Scheringer, Martin, E-mail: Martin.Scheringer@chem.ethz.c [ETHZ, Swiss Federal Institute of Technology Zurich (Switzerland); Ludwig, Christian, E-mail: Christian.Ludwig@psi.c [PSI, Paul Scherrer Institue (Switzerland); Ulrich, Andrea, E-mail: Andrea.Ulrich@empa.c [EMPA, Swiss Federal Laboratories for Materials Testing and Research (Switzerland)
2010-09-15
This study describes methods developed for reliable quantification of size- and element-specific release of engineered nanoparticles (ENP) from consumer spray products. A modified glove box setup was designed to allow controlled spray experiments in a particle-minimized environment. Time dependence of the particle size distribution in a size range of 10-500 nm and ENP release rates were studied using a scanning mobility particle sizer (SMPS). In parallel, the aerosol was transferred to a size-calibrated electrostatic TEM sampler. The deposited particles were investigated using electron microscopy techniques in combination with image processing software. This approach enables the chemical and morphological characterization as well as quantification of released nanoparticles from a spray product. The differentiation of solid ENP from the released nano-sized droplets was achieved by applying a thermo-desorbing unit. After optimization, the setup was applied to investigate different spray situations using both pump and gas propellant spray dispensers for a commercially available water-based nano-silver spray. The pump spray situation showed no measurable nanoparticle release, whereas in the case of the gas spray, a significant release was observed. From the results it can be assumed that the homogeneously distributed ENP from the original dispersion grow in size and change morphology during and after the spray process but still exist as nanometer particles of size <100 nm. Furthermore, it seems that the release of ENP correlates with the generated aerosol droplet size distribution produced by the spray vessel type used. This is the first study presenting results concerning the release of ENP from spray products.
International Nuclear Information System (INIS)
Hagendorfer, Harald; Lorenz, Christiane; Kaegi, Ralf; Sinnet, Brian; Gehrig, Robert; Goetz, Natalie V.; Scheringer, Martin; Ludwig, Christian; Ulrich, Andrea
2010-01-01
This study describes methods developed for reliable quantification of size- and element-specific release of engineered nanoparticles (ENP) from consumer spray products. A modified glove box setup was designed to allow controlled spray experiments in a particle-minimized environment. Time dependence of the particle size distribution in a size range of 10-500 nm and ENP release rates were studied using a scanning mobility particle sizer (SMPS). In parallel, the aerosol was transferred to a size-calibrated electrostatic TEM sampler. The deposited particles were investigated using electron microscopy techniques in combination with image processing software. This approach enables the chemical and morphological characterization as well as quantification of released nanoparticles from a spray product. The differentiation of solid ENP from the released nano-sized droplets was achieved by applying a thermo-desorbing unit. After optimization, the setup was applied to investigate different spray situations using both pump and gas propellant spray dispensers for a commercially available water-based nano-silver spray. The pump spray situation showed no measurable nanoparticle release, whereas in the case of the gas spray, a significant release was observed. From the results it can be assumed that the homogeneously distributed ENP from the original dispersion grow in size and change morphology during and after the spray process but still exist as nanometer particles of size <100 nm. Furthermore, it seems that the release of ENP correlates with the generated aerosol droplet size distribution produced by the spray vessel type used. This is the first study presenting results concerning the release of ENP from spray products.
Nanoscale architectural tuning of parylene patch devices to control therapeutic release rates
International Nuclear Information System (INIS)
Pierstorff, Erik; Lam, Robert; Ho, Dean
2008-01-01
The advent of therapeutic functionalized implant coatings has significantly impacted the medical device field by enabling prolonged device functionality for enhanced patient treatment. Incorporation of drug release from a stable, biocompatible surface is instrumental in decreasing systemic application of toxic therapeutics and increasing the lifespan of implants by the incorporation of antibiotics and anti-inflammatories. In this study, we have developed a parylene C-based device for controlled release of Doxorubicin, an anti-cancer chemotherapy and definitive read-out for preserved drug functionality, and further characterized the parylene deposition condition-dependent tunability of drug release. Drug release is controlled by the deposition of a layer of 20-200 nm thick parylene over the drug layer. This places a porous layer above the Doxorubicin, limiting drug elution based on drug accessibility to solvent and the solvent used. An increase in the thickness of the porous top layer prolongs the elution of active drug from the device from, in the conditions tested, the order of 10 min to the order of 2 d in water and from the order of 10 min to no elution in PBS. Thus, the controlled release of an anti-cancer therapeutic has been achieved via scalably fabricated, parylene C-encapsulated drug delivery devices.
Directory of Open Access Journals (Sweden)
Ghavam M
2010-01-01
Full Text Available Background and Aims: In spite of the advances achieved in the field of dentin adhesives, the longevity of bond to dentin is still a challenge. According to recent studies, Matrix Metaloproteinase (MMP inhibitors can increase clinical longevity of bonding and decrease leakage. The aim of this study was to evaluate the amount and pattern of doxycycline release from an experimental dentin adhesive containing this MMP inhibitor. Materials and Methods: In this experimental study, specimens containing 0.25 and 0.5 loading percent of doxycycline in an experimental monomer were prepared in cylindrical moulds of 12 mm diameter and 2 mm thickness. The adhesive monomer was composed of 12 wt% Bis-GMA, 10 wt% TMPTMA, 28 wt% HEMA and 50 wt% ethanol. Camphorquinone and amine were used as initiators. Results: Addition of 0.25 and 0.5 w% doxycycline showed linear release in both groups. Increasing the loading percent of doxycycline caused more release. The release continued during the test period. Conclusion: Doxycycline release was observed from the experimental adhesive. Further studies in this field will help in preparing adhesive systems with more clinical longevity.
Dam Breach Release of Non-Cohesive Sediments: Channel Response and Recovery Rates
Collins, M. J.; Boardman, G.; Banks, W.; Andrews, M.; Conlon, M.; Dillow, J. J. A.; Gellis, A.; Lowe, S.; McClain, S.; Miller, A. J.; Snyder, N. P.; Wilcock, P. R.
2014-12-01
Dam removals featuring unchecked releases of non-cohesive sediments are excellent opportunities to learn more about stream channel response to abrupt increases in bed material supply that can occur deliberately or by natural processes like landslides and volcanic eruptions. Understanding channel response to sediment pulses, including response rates, is essential because human uses of river channels and floodplains are impacted by these events as are aquatic habitats. We had the opportunity to study a dam removal site at the Simkins Dam in Maryland, USA, that shares many important geophysical attributes of another well-studied dam removal in the humid northeast United States [Merrimack Village Dam, New Hampshire; Pearson et al., 2011]. The watershed sizes are the same order of magnitude (102 km2), and at both sites relatively low head dams were removed (~ 3-4 m) and ~60,000 m3 of dominantly sand-sized sediments discharged to low-gradient reaches immediately downstream. Analyzing four years of repeat morphometry and bed sediment grain size surveys at the Simkins site on the Patapsco River, as well as continuous discharge and suspended sediment gaging data, we clearly document a two-phase response in the upstream reach as described by Pearson et al. [2011] for their New Hampshire site and noted at other dam removals [e.g., Major et al., 2012]. In the early phase, approximately 50% of the impounded sediment mass was eroded rapidly over a period of about three months when flows were very modest (Figure 1). After incision to base level and channel widening in the former impoundment, a second phase began when further erosion depended on floods large enough to access impounded sediments more distant from the newly-formed channel. We also found important differences in the upstream responses at the Maryland and New Hampshire sites that appear to be related to valley type (non-glaciated versus glaciated, respectively). Response variances immediately downstream between the
75 FR 66057 - Waybill Data Released in Three-Benchmark Rail Rate Proceedings
2010-10-27
... (CSX Transp. II), 584 F.3d 1076 (DC Cir. 2009), the Board modified its simplified rail rate guidelines...- Benchmark approach for smaller rail rate disputes. The Three-Benchmark method compares a challenged rate of...: The RSAM and R/VC >180 benchmarks. See Rate Guidelines--Non-Coal Proceedings, (Rate Guidelines) 1 S.T...
2013-06-24
... DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Quarterly IRS Interest Rates... the public of the quarterly Internal Revenue Service interest rates used to calculate interest on... beginning July 1, 2013, the interest rates for overpayments will be 2 percent for corporations and 3 percent...
2012-03-27
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2011-07-13
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2010-04-19
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2013-10-23
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2010-06-30
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2012-09-27
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On the Ni-Ion release rate from surfaces of binary NiTi shape memory alloys
Ševčíková, Jana; Bártková, Denisa; Goldbergová, Monika; Kuběnová, Monika; Čermák, Jiří; Frenzel, Jan; Weiser, Adam; Dlouhý, Antonín
2018-01-01
The study is focused on Ni-ion release rates from NiTi surfaces exposed in the cell culture media and human vascular endothelial cell (HUVEC) culture environments. The NiTi surface layers situated in the depth of 70 μm below a NiTi oxide scale are affected by interactions between the NiTi alloys and the bio-environments. The finding was proved with use of inductively coupled plasma mass spectrometry and electron microscopy experiments. As the exclusive factor controlling the Ni-ion release rates was not only thicknesses of the oxide scale, but also the passivation depth, which was two-fold larger. Our experimental data strongly suggested that some other factors, in addition to the Ni concentration in the oxide scale, admittedly hydrogen soaking deep below the oxide scale, must be taken into account in order to rationalize the concentrations of Ni-ions released into the bio-environments. The suggested role of hydrogen as the surface passivation agent is also in line with the fact that the Ni-ion release rates considerably decrease in NiTi samples that were annealed in controlled hydrogen atmospheres prior to bio-environmental exposures.
Experimental validation of calculated capture rate for nucleus involved in fuel cycle
International Nuclear Information System (INIS)
Benslimane-Bouland, A.
1997-09-01
The framework of this study was the evaluation of the nuclear data requirements for Actinides and Fission Products applied to current nuclear reactors as well as future applications. This last item includes extended irradiation campaigns, 100 % Mixed Oxide fuel, transmutation or even incineration. The first part of this study presents different types of integral measurements which are available for capture rate measurements, as well as the methods used for reactor core calculation route design and nuclear data library validation. The second section concerns the analysis of three specific irradiation experiments. The results have shown the extent of the current knowledge on nuclear data as well as the associated uncertainties. The third and last section shows both the coherency between all the results, and the statistical method applied for nuclear data library adjustment. A relevant application of this method has demonstrated that only specifically chosen integral experiments can be of use for the validation of nuclear data libraries. The conclusion is reached that even if co-ordinated efforts between reactor and nuclear physicists have made possible a huge improvement in the knowledge of capture cross sections of the main nuclei such as uranium and plutonium, some improvements are currently necessary for the minor actinides (Np, Am and Cm). Both integral and differential measurements are recommended to improve the knowledge of minor actinide cross sections. As far as integral experiments are concerned, a set of criteria to be followed during the experimental conception have been defined in order to both reduce the number of required calculation approximations, and to increase as much as possible the maximum amount of extracted information. (author)
International Nuclear Information System (INIS)
Mould, Richard F.
1995-01-01
Purpose/Objective: To explain some of the most useful statistical calculation procedures which are relevant to radiation oncologists and to provide insights on what tests and procedures should be used in various situations such as when survival rates and their associated standard errors have to be determined. To describe some of the problems and pitfalls in clinical trial designs which have to be overcome if a trial is to have the possibility of reaching a successful conclusion. To review methods of computing criteria to quantitatively describe criteria of success (eg. quality of life, long-term survival, cure) of radiation oncology and to suggest possible future statistical improvements in this area. Chi-Squared Test: The chi-squared test is probably the most useful of the tests of statistical significance for the radiation oncologist. Applications will be described, including goodness of fit tests and 2x2 contingency tables which are the simplest of the generalized nxm contingency tables. Degrees of Freedom and P<0.05 for Significance Testing: An Introduction will be given to the meaning of P<0.05 in relation to significance testing and the use of tables of critical values of a test statistic (eg. chi-squared) which are given as a function of degrees of freedom and P-values. Survival Rate Calculations for Grouped and Ungrouped Data: The life-table method (sometimes termed the actuarial method) will be explained for both grouped data (eg. survival times grouped in annual intervals for patients who have died and for those who are still alive or lost to follow-up) and for ungrouped data (when individual survival times are used). The method for ungrouped data is variously termed the Kaplan-Meier or Product Limit method. Logrank Test: This is the most useful test for comparison of the survival experience of two groups of patients and its use will be explained. In part the computation is similar to that for the Kaplan-Meier/Product Limit method
Energy Technology Data Exchange (ETDEWEB)
Mould, Richard F
1995-07-01
Purpose/Objective: To explain some of the most useful statistical calculation procedures which are relevant to radiation oncologists and to provide insights on what tests and procedures should be used in various situations such as when survival rates and their associated standard errors have to be determined. To describe some of the problems and pitfalls in clinical trial designs which have to be overcome if a trial is to have the possibility of reaching a successful conclusion. To review methods of computing criteria to quantitatively describe criteria of success (eg. quality of life, long-term survival, cure) of radiation oncology and to suggest possible future statistical improvements in this area. Chi-Squared Test: The chi-squared test is probably the most useful of the tests of statistical significance for the radiation oncologist. Applications will be described, including goodness of fit tests and 2x2 contingency tables which are the simplest of the generalized nxm contingency tables. Degrees of Freedom and P<0.05 for Significance Testing: An Introduction will be given to the meaning of P<0.05 in relation to significance testing and the use of tables of critical values of a test statistic (eg. chi-squared) which are given as a function of degrees of freedom and P-values. Survival Rate Calculations for Grouped and Ungrouped Data: The life-table method (sometimes termed the actuarial method) will be explained for both grouped data (eg. survival times grouped in annual intervals for patients who have died and for those who are still alive or lost to follow-up) and for ungrouped data (when individual survival times are used). The method for ungrouped data is variously termed the Kaplan-Meier or Product Limit method. Logrank Test: This is the most useful test for comparison of the survival experience of two groups of patients and its use will be explained. In part the computation is similar to that for the Kaplan-Meier/Product Limit method.
Thermal ramp rate effects on mixed-oxide fuel swelling/gas release
International Nuclear Information System (INIS)
Hinman, C.A.; Randklev, E.H.
1979-01-01
Macroscopic swelling behavior of PNL-10 was compared to that of PNL-2 fuel and it was found that the swelling-threshold behavior is similar for similar thermal conditions. Transient fission gas release for the PNL-10 fuel is very similar to that observed for the PNL-2 fuel for similar thermal conditions
Stumvoll, M; Chintalapudi, U; Perriello, G; Welle, S; Gutierrez, O; Gerich, J
1995-11-01
Despite ample evidence that the kidney can both produce and use appreciable amounts of glucose, the human kidney is generally regarded as playing a minor role in glucose homeostasis. This view is based on measurements of arteriorenal vein glucose concentrations indicating little or no net release of glucose. However, inferences from net balance measurements do not take into consideration the simultaneous release and uptake of glucose by the kidney. Therefore, to assess the contribution of release and uptake of glucose by the human kidney to overall entry and removal of plasma glucose, we used a combination of balance and isotope techniques to measure renal glucose net balance, fractional extraction, uptake and release as well as overall plasma glucose appearance and disposal in 10 normal volunteers under basal postabsorptive conditions and during a 3-h epinephrine infusion. In the basal postabsorptive state, there was small but significant net output of glucose by the kidney (66 +/- 22 mumol.min-1, P = 0.016). However, since renal glucose fractional extraction averaged 2.9 +/- 0.3%, there was considerable renal glucose uptake (2.3 +/- 0.2 mumol.kg-1.min-1) which accounted for 20.2 +/- 1.7% of systemic glucose disposal (11.4 +/- 0.5 mumol.kg-1.min-1). Renal glucose release (3.2 +/- 0.2 mumol.kg-1.min-1) accounted for 27.8 +/- 2.1% of systemic glucose appearance (11.4 +/- 0.5 mumol.kg-1.min-1). Epinephrine infusion, which increased plasma epinephrine to levels observed during hypoglycemia (3722 +/- 453 pmol/liter) increased renal glucose release nearly twofold (5.2 +/- 0.5 vs 2.8 +/- 0.1 mol.kg-1.min-1, P = 0.01) so that at the end of the infusion, renal glucose release accounted for 40.3 +/- 5.5% of systemic glucose appearance and essentially all of the increase in systemic glucose appearance. These observations suggest an important role for the human kidney in glucose homeostasis.
Cappon, Giacomo; Marturano, Francesca; Vettoretti, Martina; Facchinetti, Andrea; Sparacino, Giovanni
2018-05-01
The standard formula (SF) used in bolus calculators (BCs) determines meal insulin bolus using "static" measurement of blood glucose concentration (BG) obtained by self-monitoring of blood glucose (SMBG) fingerprick device. Some methods have been proposed to improve efficacy of SF using "dynamic" information provided by continuous glucose monitoring (CGM), and, in particular, glucose rate of change (ROC). This article compares, in silico and in an ideal framework limiting the exposition to possibly confounding factors (such as CGM noise), the performance of three popular techniques devised for such a scope, that is, the methods of Buckingham et al (BU), Scheiner (SC), and Pettus and Edelman (PE). Using the UVa/Padova Type 1 diabetes simulator we generated data of 100 virtual subjects in noise-free, single-meal scenarios having different preprandial BG and ROC values. Meal insulin bolus was computed using SF, BU, SC, and PE. Performance was assessed with the blood glucose risk index (BGRI) on the 9 hours after meal. On average, BU, SC, and PE improve BGRI compared to SF. When BG is rapidly decreasing, PE obtains the best performance. In the other ROC scenarios, none of the considered methods prevails in all the preprandial BG conditions tested. Our study showed that, at least in the considered ideal framework, none of the methods to correct SF according to ROC is globally better than the others. Critical analysis of the results also suggests that further investigations are needed to develop more effective formulas to account for ROC information in BCs.
Calculations for energies, transition rates, and lifetimes in Al-like Kr XXIV
Zhang, C. Y.; Si, R.; Liu, Y. W.; Yao, K.; Wang, K.; Guo, X. L.; Li, S.; Chen, C. Y.
2018-05-01
Using the second-order many-body perturbation theory (MBPT) method, a complete and accurate data set of excitation energies, lifetimes, wavelengths, and electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) line strengths, transition rates, and oscillator strengths for the lowest 880 levels arising from the 3l3 (0 ≤ l ≤ 2), 3l2 4l‧ (0 ≤ l ≤ 2, 0 ≤l‧ ≤ 3), 3s2 5 l (0 ≤ l ≤ 4), 3p2 5 l (0 ≤ l ≤ 1), and 3s3p5 l (0 ≤ l ≤ 4) configurations in Al-like Kr XXIV is provided. Comparisons are made with available experimental and theoretical results. Our calculated energies are expected to be accurate enough to facilitate identifications of observed lines involving the n = 4 , 5 levels. The complete data set is also useful for modeling and diagnosing fusion plasma.
DEFF Research Database (Denmark)
van Harrevelt, Rob; Honkala, Johanna Karoliina; Nørskov, Jens Kehlet
2005-01-01
Quantum-mechanical calculations of the reaction rate for dissociative adsorption of N-2 on stepped Ru(0001) are presented. Converged six-dimensional quantum calculations for this heavy-atom reaction have been performed using the multiconfiguration time-dependent Hartree method. A potential...
45 CFR 261.36 - Do welfare reform waivers affect the calculation of a State's participation rates?
2010-10-01
..., DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING THAT RECIPIENTS WORK What Are the Work Activities and How Do They Count? § 261.36 Do welfare reform waivers affect the calculation of a State's participation rates... 45 Public Welfare 2 2010-10-01 2010-10-01 false Do welfare reform waivers affect the calculation...
International Nuclear Information System (INIS)
Czarnecki, J.; Volkle, H.; Pretre, S.
1980-01-01
The increase of radiation doses in the vicinity of the Swiss Nuclear Power Stations due to airborne releases is generally expected to be below one mrem/year (about one percent of the natural radiation dose). To prove this expected rate, long term measurements with pressure ionization chambers in the vicinity of the Muhleberg plant (BWR) were conducted. Two of these chambers were installed at places where the greatest dose rates from the noble gas plumes were expected in the two prevailing wind directions. The local dose rates were continuously registered on magnetic tape to allow minicomputer evaluation. After the fuel change in the summer of 1976 the noble gas releases from Muhleberg dropped considerably. From that time the noble gas releases consisted of a very low continuous component and some rare short-time spike compoments resulting from turbine and reactor trips. The dose due to the low continuous component was determined by correlating the dose rates at the measuring points with the release measure--ments at the stack and with weather conditions, and by subtracting the natural background. The short noble gas spikes lasted from minutes to some hours and caused small dose rate increases which were easily measured with the ionization chambers, and usually amounted to doses of some microroentgens. By further correlating these dose peaks with wind direction and stack emission measurements, determination of short time atmospheric dilution factors for existing weather situations became possible. By this process, the very low annual environmental doses in the range of 1 mrem per year were determined. (author)
International Nuclear Information System (INIS)
Paschoa, A.S.; Baptista, G.B.
1977-01-01
A method for the calculation of upper limit internal alpha dose rates to aquatic organisms is presented. The mean alpha energies per disintegration of radionuclides of interest are listed to be used in standard methodologies to calculate dose to aquatic biota. As an application, the upper limits for the alpha dose rates from 239 Pu to the total body of plankton are estimated based on data available in open literature [pt
International Nuclear Information System (INIS)
Zheng, X.J.; Metzger, D.R.; Sauve, R.G.
1995-01-01
A fracture criterion based on energy balance is proposed for elasto-plastic cracking at hydrides in zirconium, assuming a finite length of crack advance. The proposed elasto-plastic energy release rate is applied to the crack initiation at hydrides in smooth and notched surfaces, as well as the subsequent delayed hydride cracking (DHC) considering limited crack-tip plasticity. For a smooth or notched surface of an elastic body, the fracture parameter is related to the stress intensity factor for the initiated crack. For DHC, a unique curve relates the non-dimensionalized elasto-plastic energy release rate with the length of crack extension relative to the plastic zone size. This fracture criterion explains experimental observations concerning DHC in a qualitative manner. Quantitative comparison with experiments is made for fracture toughness and DHC tests on specimens containing certain hydride structures; very good agreement is obtained. ((orig.))
Directory of Open Access Journals (Sweden)
Lorenz Bott-Flügel
Full Text Available The release of the neurotransmitter norepinephrine (NE is modulated by presynaptic adenosine receptors. In the present study we investigated the effect of a partial activation of this feedback mechanism. We hypothesized that partial agonism would have differential effects on NE release in isolated hearts as well as on heart rate in vivo depending on the genetic background and baseline sympathetic activity. In isolated perfused hearts of Wistar and Spontaneously Hypertensive Rats (SHR, NE release was induced by electrical stimulation under control conditions (S1, and with capadenoson 6 · 10(-8 M (30 µg/l, 6 · 10(-7 M (300 µg/l or 2-chloro-N(6-cyclopentyladenosine (CCPA 10(-6 M (S2. Under control conditions (S1, NE release was significantly higher in SHR hearts compared to Wistar (766+/-87 pmol/g vs. 173+/-18 pmol/g, p<0.01. Capadenoson led to a concentration-dependent decrease of the stimulation-induced NE release in SHR (S2/S1 = 0.90 ± 0.08 with capadenoson 6 · 10(-8 M, 0.54 ± 0.02 with 6 · 10(-7 M, but not in Wistar hearts (S2/S1 = 1.05 ± 0.12 with 6 · 10(-8 M, 1.03 ± 0.09 with 6 · 10(-7 M. CCPA reduced NE release to a similar degree in hearts from both strains. In vivo capadenoson did not alter resting heart rate in Wistar rats or SHR. Restraint stress induced a significantly greater increase of heart rate in SHR than in Wistar rats. Capadenoson blunted this stress-induced tachycardia by 45% in SHR, but not in Wistar rats. Using a [(35S]GTPγS assay we demonstrated that capadenoson is a partial agonist compared to the full agonist CCPA (74+/-2% A(1-receptor stimulation. These results suggest that partial adenosine A(1-agonism dampens stress-induced tachycardia selectively in rats susceptible to strong increases in sympathetic activity, most likely due to a presynaptic attenuation of NE release.
Direct quantum mechanical calculation of the F + H{sub 2} {yields} HF + H thermal rate constant
Energy Technology Data Exchange (ETDEWEB)
Moix, Marc [Computer Simulation and Modeling (COSMO) Lab, Parc Cientific de Barcelona, Josep Samitier 5, 08028 Barcelona (Spain); Institut de Quimica Teorica i Computacional de la UB (IQTCUB), Universitat de Barcelona (Spain); Huarte-Larranaga, Fermin [Computer Simulation and Modeling (COSMO) Lab, Parc Cientific de Barcelona, Josep Samitier 5, 08028 Barcelona (Spain); Institut de Quimica Teorica i Computacional de la UB (IQTCUB), Universitat de Barcelona (Spain)], E-mail: fhuarte@pcb.ub.es
2008-07-03
Accurate full-dimensional quantum mechanical thermal rate constant values have been calculated for the F+H{sub 2}{yields}HF+H reaction on the Stark-Werner ab initio potential energy surface. These calculations are based on a flux correlation functions and employ a rigorous statistical sampling scheme to account for the overall rotation and the MCTDH scheme for the wave packet propagation. Our results shed some light on discrepancies on the thermal rate found for previous flux correlation based calculations with respect to accurate reactive scattering results. The resonance pattern of the all-J cumulative reaction probability is analyzed in terms of the partial wave contributions.
Energy Technology Data Exchange (ETDEWEB)
Sugimoto, O [Chugoku Electric Power Co. Inc., Hiroshima (Japan); Sawaguchi, Y; Kaneko, M
1979-03-01
A computer code, designated GAMMA-CLOUD, has been developed by specialists of electric power companies to meet requests from the companies to have a unified means of calculating annual external doses from routine releases of radioactive gaseous effluents from nuclear power plants, based on the Japan Atomic Energy Commission's guides for environmental dose evaluation. GAMMA-CLOUD is written in FORTRAN language and its required capacity is less than 100 kilobytes. The average ..gamma..-exposure at an observation point can be calculated within a few minutes with comparable precision to other existing codes.
International Nuclear Information System (INIS)
Maudlin, I.
1990-01-01
In areas where sleeping sickness is endemic, it is the practice of sterile insect technique (SIT) programmes to give sterilized males a bloodmeal before release into the wild in order to reduce the risk of these released flies acting as disease vectors. This strategy has been adopted because of experimental evidence which showed that it was essential to infect flies at their first feed to establish a Tripanosoma brucei gambiense or T. b rhodesiense infection in tsetse flies. The aim of the work was to test artificial tsetse diets produced in the IAEA Laboratory at Seibersdorf in order to determine whether they were as effective as whole blood in inhibiting T. brucei sensu lato (sl) infections in flies. Seven artificial diets were tested with T.b. rhodesiense; Glossina morsitans morsitans males were fed one meal of the diet and then starved for 3 days before the infective feed. None of these diets significantly altered the infection rate of the treated flies and the seven groups produced statistically homogeneous results, with a mean midgut rate of 16% (control flies fed pig blood: 17%). Flies infected as tenerals with the same trypanosome stock produced midgut rates of 61%. Three of the diets were also tested with a T. congolense stock. There were no significant differences between flies fed artificial (mean midgut infection rate: 15%) and whole blood diets (19%). G. m. morsitans infected as tenerals with this trypanosome stock produced midgut rates of 66%. As with T. brucei sl infections, teneral flies were far more likely to develop a T. congolense infection than fed flies; this result suggests that all the tsetse flies used in SIT programmes should be fed before release in order to reduce the risk both to man and his livestock. Artificial diets are as effective as whole blood in inhibiting trypanosome infections. The effect of bloodmeal on the fly infection rates is discussed in relation to lectin production in fed flies. (author). 13 refs, 2 tabs
International Nuclear Information System (INIS)
Hu Erbang
1988-01-01
A series (22) of atmospheric tracer experiments with 100m release height have been performed at the kernforschungszentrum karlsruhe (KfK) of West Germany over a terrain of major roughness (Z 0 = 1.5 m). The concentration data of the tracers are statistically analysed in which 5 methods of stability classification are used. The results show that the normalized diffusion factors predicted by Gaussian plume dispersion model is in good agreement with the observed ones for elevated releases over a terrain of major roughness. Differnent sets of dispersion parameters could be obtained for the same series of atmospheric tracer experiments if different methods of classification are applied. The same method of stability classification should be used for the application of these dispersion parameters to evaluate the environment impact
MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness
International Nuclear Information System (INIS)
DeLorenzo, M; Wu, D; Rutel, I; Yang, K
2015-01-01
Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation
MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness
Energy Technology Data Exchange (ETDEWEB)
DeLorenzo, M [Oklahoma University Health Sciences Center, Oklahoma City, OK (United States); Wu, D [University of Oklahoma Health Sciences Center, Oklahoma City, Ok (United States); Rutel, I [University of Oklahoma Health Science Center, Oklahoma City, OK (United States); Yang, K [Massachusetts General Hospital, Boston, MA (United States)
2015-06-15
Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation
Hot-electron-mediated desorption rates calculated from excited-state potential energy surfaces
DEFF Research Database (Denmark)
Olsen, Thomas; Gavnholt, Jeppe; Schiøtz, Jakob
2009-01-01
We present a model for desorption induced by (multiple) electronic transitions [DIET (DIMET)] based on potential energy surfaces calculated with the delta self-consistent field extension of density-functional theory. We calculate potential energy surfaces of CO and NO molecules adsorbed on variou...
International Nuclear Information System (INIS)
Vergnaud, T.; Bourdet, L.; Gonnord, J.; Nimal, J.C.; Champion, G.
1984-01-01
Conception of a reactor building requires large openings in the primary concrete shield for a postulated loss-of-coolant accident. Through these openings neutrons escape and produce dose rates in several parts of the reactor building. Some calculations using ANISN, DOT and essentially TRIPOLI-2 codes allow to compute the neutron dose rates at several places such as reactor containment operating floor and containment annulus. Some complementary shields are provided and the instrumentations are placed in area where the dose rate is lower. Comparisons are presented between measurements and calculations
International Nuclear Information System (INIS)
Baston, V.F.; Hofstetter, K.J.; Ryan, R.F.
1987-01-01
Chemical and radiochemical analyses of reactor coolant samples taken during defueling of the Three Mile Island Unit-2 (TMI-2) reactor provide relevant data to assist in understanding the solution chemistry of the radionuclides retained within the TMI-2 reactor coolant system. Hydrogen peroxide was added to various plant systems to provide disinfection for microbial contamination and has provided the opportunity to observe radionuclide release under different oxygen chemical potentials. A comparison of the radionuclide release rates with and without hydrogen peroxide has been made for these separate but related cases, i.e., the fuel transfer canal and connecting spent-fuel pool A with the TMI-2 reactor plenum in the fuel transfer canal, core debris grab sample laboratory experiments, and the reactor vessel fluid and associated core debris. Correlation and comparison of these data indicate a physical parameter dependence (surface-to-volume ratio) affecting all radionuclide release; however, selected radionuclides also demonstrate a chemical dependence release under the different oxygen chemical potentials. Chemical and radiochemical analyses of reactor coolant samples taken during defueling of the Three Mile Island Unit-2 (TMI-2) reactor provide relevant data to assist in understanding the solution chemistry of the radionuclides retained within the TMI-2 reactor coolant system
Lung deposition of sub-micron aerosols calculated as a function of age and breathing rate
International Nuclear Information System (INIS)
James, A.C.
1978-01-01
Experimental measurements of lung deposition and especially of regional deposition, of aerosols in the sub-micron size range have been so few that it is worthwhile establishing a method of calculation. A computer routine has therefore been developed to calculate aerosol deposition in successive bronchial and bronchiolar generations of the Weibel 'A' model of human lung for the sub-micron size range where deposition occurs solely by diffusion. This model can be scaled to represent lungs at various ages and vital capacities. Some calculated results are presented here and compared with measurements of lung deposition made under carefully controlled conditions in humans. (author)
Energy Technology Data Exchange (ETDEWEB)
Van Hove, W.; Van Laeken, K.; Bartsoen, L. [Belgatom, Brussels (Belgium)] [and others
1995-09-01
To enable a more realistic and accurate calculation of the radiological consequences of a SGTR, a fission product transport model was developed. As the radiological releases strongly depend on the thermal-hydraulic transient, the model was included in the RELAP5 input decks of the Belgian NPPs. This enables the coupled calculation of the thermal-hydraulic transient and the radiological release. The fission product transport model tracks the concentration of the fission products in the primary circuit, in each of the SGs as well as in the condenser. This leads to a system of 6 coupled, first order ordinary differential equations with time dependent coefficients. Flashing, scrubbing, atomisation and dry out of the break flow are accounted for. Coupling with the thermal-hydraulic calculation and correct modelling of the break position enables an accurate calculation of the mixture level above the break. Pre- and post-accident spiking in the primary circuit are introduced. The transport times in the FW-system and the SG blowdown system are also taken into account, as is the decontaminating effect of the primary make-up system and of the SG blowdown system. Physical input parameters such as the partition coefficients, half life times and spiking coefficients are explicitly introduced so that the same model can be used for iodine, caesium and noble gases.
International Nuclear Information System (INIS)
Tierney, M.S.
1991-11-01
The Waste Isolation Pilot Plant (WIPP), in southeastern New Mexico, is a research and development facility to demonstrate safe disposal of defense-generated transuranic waste. The US Department of Energy will designate WIPP as a disposal facility if it meets the US Environmental Protection Agency's standard for disposal of such waste; the standard includes a requirement that estimates of cumulative releases of radioactivity to the accessible environment be incorporated in an overall probability distribution. The WIPP Project has chosen an approach to calculation of an overall probability distribution that employs the concept of scenarios for release and transport of radioactivity to the accessible environment. This report reviews the use of Monte Carlo methods in the calculation of an overall probability distribution and presents a logical and mathematical foundation for use of the scenario concept in such calculations. The report also draws preliminary conclusions regarding the shape of the probability distribution for the WIPP system; preliminary conclusions are based on the possible occurrence of three events and the presence of one feature: namely, the events ''attempted boreholes over rooms and drifts,'' ''mining alters ground-water regime,'' ''water-withdrawal wells provide alternate pathways,'' and the feature ''brine pocket below room or drift.'' Calculation of the WIPP systems's overall probability distributions for only five of sixteen possible scenario classes that can be obtained by combining the four postulated events or features
Saeedi, Majid; Morteza-Semnani, Katayoun; Sagheb-Doust, Mehdi
2013-03-01
Polysaccharide mucilage derived from the seeds of Plantago major L. (family Plantaginaceae) was investigated for use in matrix formulations containing propranolol hydrochloride. HPMC K4M and tragacanth were used as standards for comparison. The hardness, tensile strength, and friability of tablets increased as the concentration of mucilage increased, indicating good compactibility of mucilage powders. The rate of release of propranolol hydrochloride from P. major mucilage matrices was mainly controlled by the drug/mucilage ratio. Formulations containing P. major mucilage were found to exhibit a release rate comparable to HPMC containing matrices at a lower drug/polymer ratio (drug/HPMC 2:1). These results demonstrated that P. major mucilage is a better release retardant compared to tragacanth at an equivalent content. The results of kinetic analysis showed that in F3 (containing 1:2 drug/mucilage) the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets. The DSC and FT-IR studies showed that no formation of complex between the drug and mucilage or changes in crystallinity of the drug had occurred.
Forms and rates of release of Cs-137 in 2 peat soils
International Nuclear Information System (INIS)
Livens, F.R.; Howe, M.T.; Hemingway, J.D.; Goulding, K.W.T.; Howard, B.J.; IACR Rothamsted, Harpenden; Liverpool Univ.; Institute of Terrestrial Ecology, Grange-on-Sands
1996-01-01
Cation exchange resin saturated with H+ and Ca2+ was used to extract Cs-137 from peat soil at two sites in Britain affected by Cs-137 deposition following the Chernobyl accident. The technique identified three classes of Cs-137, similar to those observed for K+ in soils: ''Fast'', ''Intermediate'' and ''Slow''. These classes are probably related to the selectivity for Cs-137 of the cation exchange sites on the organic matter and the clay minerals, and to the structure of the soil. With one exception, most Cs-137 was in the ''Slow'' form and was only very slowly released to the resins, if at all. However, there was enough Cs-137 in the ''Fast'' and ''Intermediate'' forms to contaminate pasture and thus grazing animals for some years. Based on the resin technique, it is estimated that contamination will persist for several decades in uplands contaminated at these activity concentrations. (Author)
International Nuclear Information System (INIS)
Walker, C.T.; Mogensen, M.
1987-01-01
The radial distribution of grain boundary gas in a PWR and a BWR fuel is reported. The measurements were made using a new approach involving X-ray fluorescence analysis and electron probe microanalysis. In both fuels the concentration of grain boundary gas was much higher than hitherto suspected. The gas was mainly contained in the bubble/pore structure. The factors that determined the fraction of gas released from the grains and the level of gas retention on the grain boundaries are identified and discussed. The variables involved are the local fuel stoichiometry, the amount of open porosity, the magnitude of the local compressive hydrostatic stress and the interaction of metallic precipitates with gas bubbles on the grain faces. It is concluded that under transient conditions the interlinkage of gas bubbles on the grain faces and the subsequent formation of grain edge tunnels is the rate determining step for gas release; at least when high burn-up fuel is involved. (orig.)
Liu, Dapeng
2017-01-10
Reaction rate coefficients for the reaction of hydroxyl (OH) radicals with nine large branched alkanes (i.e., 2-methyl-3-ethyl-pentane, 2,3-dimethyl-pentane, 2,2,3-trimethylbutane, 2,2,3-trimethyl-pentane, 2,3,4-trimethyl-pentane, 3-ethyl-pentane, 2,2,3,4-tetramethyl-pentane, 2,2-dimethyl-3-ethyl-pentane, and 2,4-dimethyl-3-ethyl-pentane) are measured at high temperatures (900-1300 K) using a shock tube and narrow-line-width OH absorption diagnostic in the UV region. In addition, room-temperature measurements of six out of these nine rate coefficients are performed in a photolysis cell using high repetition laser-induced fluorescence of OH radicals. Our experimental results are combined with previous literature measurements to obtain three-parameter Arrhenius expressions valid over a wide temperature range (300-1300 K). The rate coefficients are analyzed using the next-nearest-neighbor (N-N-N) methodology to derive nine tertiary (T003, T012, T013, T022, T023, T111, T112, T113, and T122) site-specific rate coefficients for the abstraction of H atoms by OH radicals from branched alkanes. Derived Arrhenius expressions, valid over 950-1300 K, are given as (the subscripts denote the number of carbon atoms connected to the next-nearest-neighbor carbon): T003 = 1.80 × 10-10 exp(-2971 K/T) cm3 molecule-1 s-1; T012 = 9.36 × 10-11 exp(-3024 K/T) cm3 molecule-1 s-1; T013 = 4.40 × 10-10 exp(-4162 K/T) cm3 molecule-1 s-1; T022 = 1.47 × 10-10 exp(-3587 K/T) cm3 molecule-1 s-1; T023 = 6.06 × 10-11 exp(-3010 K/T) cm3 molecule-1 s-1; T111 = 3.98 × 10-11 exp(-1617 K/T) cm3 molecule-1 s-1; T112 = 9.08 × 10-12 exp(-3661 K/T) cm3 molecule-1 s-1; T113 = 6.74 × 10-9 exp(-7547 K/T) cm3 molecule-1 s-1; T122 = 3.47 × 10-11 exp(-1802 K/T) cm3 molecule-1 s-1.
DEFF Research Database (Denmark)
Vegge, Tejs
2004-01-01
The dissociation of molecular hydrogen on a Mgs0001d surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate is investigated using Density Functional Theory (DFT) calculations and rate theory. The minimum energy path and corresponding transition states are located usi...... to be rate-limiting for the ab- and desorption of hydrogen, respectively. Zero-point energy contributions are found to be substantial for the diffusion of atomic hydrogen, but classical rates are still found to be within an order of magnitude at room temperature.......The dissociation of molecular hydrogen on a Mgs0001d surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate is investigated using Density Functional Theory (DFT) calculations and rate theory. The minimum energy path and corresponding transition states are located using...
Stehle, Robert; Tesi, Chiara
2017-08-01
A basic goal in muscle research is to understand how the cyclic ATPase activity of cross-bridges is converted into mechanical force. A direct approach to study the chemo-mechanical coupling between P i release and the force-generating step is provided by the kinetics of force response induced by a rapid change in [P i ]. Classical studies on fibres using caged-P i discovered that rapid increases in [P i ] induce fast force decays dependent on final [P i ] whose kinetics were interpreted to probe a fast force-generating step prior to P i release. However, this hypothesis was called into question by studies on skeletal and cardiac myofibrils subjected to P i jumps in both directions (increases and decreases in [P i ]) which revealed that rapid decreases in [P i ] trigger force rises with slow kinetics, similar to those of calcium-induced force development and mechanically-induced force redevelopment at the same [P i ]. A possible explanation for this discrepancy came from imaging of individual sarcomeres in cardiac myofibrils, showing that the fast force decay upon increase in [P i ] results from so-called sarcomere 'give'. The slow force rise upon decrease in [P i ] was found to better reflect overall sarcomeres cross-bridge kinetics and its [P i ] dependence, suggesting that the force generation coupled to P i release cannot be separated from the rate-limiting transition. The reasons for the different conclusions achieved in fibre and myofibril studies are re-examined as the recent findings on cardiac myofibrils have fundamental consequences for the coupling between P i release, rate-limiting steps and force generation. The implications from P i -induced force kinetics of myofibrils are discussed in combination with historical and recent models of the cross-bridge cycle.
Energy Technology Data Exchange (ETDEWEB)
Robinson, R C [Atlantic Nuclear Services Ltd. (Canada); Tran, F [Ontario Hydro, Pickering, ON (Canada). Pickering Generating Station
1996-12-31
A homogenization methodology for calculation of reactivity device incremental cross-sections has been developed using reaction rate conservation (RRC). A heterogeneous transport calculation of flux was utilised to produce the homogenized cross-sections for a finite difference two group diffusion code. The RRC cross-sections have been shown to improve significantly the prediction of reactivity worth for stainless steel adjuster rods installed in Pickering NGS reactors. (author). 10 refs., 3 tabs., 6 figs.
International Nuclear Information System (INIS)
Bondars, Kh.Ya.; Lapenas, A.A.
1981-01-01
We adapted or used on ES EhVM, operating under the control of OS ES, the currently most common algorithms for calculating neutron spectra from measured reaction rates. These programs, together with the neutron cross-section and spectrum libraries, are part of the computerized information system SAIPS. The present article descibes the basic mathematical concepts used in the algorithms of the SAIPS calculation programs
International Nuclear Information System (INIS)
Lee, C.E.; Apperson, C.E. Jr.; Foley, J.E.
1976-10-01
The report describes an analytic containment building model that is used for calculating the leakage into the environment of each isotope of an arbitrary radioactive decay chain. The model accounts for the source, the buildup, the decay, the cleanup, and the leakage of isotopes that are gas-borne inside the containment building
Calculation of the external dose rate in the spent fuel pool for the case to use compact racks
International Nuclear Information System (INIS)
Passos, E.M. dos; Alves, A.S.M.
1988-01-01
The possible introduction of compact racks in the spent fuel pool of the Angra 1 Nuclear Power Plant largely inreases its storage capacity, but originates an increase of the gamma radiation sources. The precise evaluation of the effects of the adoption of this option on the external gamma dose rates and also on the thickness of the concrete shielding requires the utilization of sofisticated computer codes (QAD, ANISN), which allow the calculation of the gamma dose rates through thick shielding walls. This paper describes the utilized methodology for the calculation of the modified pool shieldings, showing the obtained results for the Angra 1 NPP case. The gamma dose rate was calculated with the point Kernel model, first analytically, and later through utilization of the tridimensional multigroup QAD computer code. (author) [pt
International Nuclear Information System (INIS)
Riahi, R.; Ben Lakhdar, Z.; Teulet, Ph.; Gleizes, A.
2006-01-01
The weighted total cross-sections (WTCS) theory is used to calculate electron impact excitation, ionization and dissociation cross-sections and rate coefficients of OH, H 2 , OH + , H 2 + , OH - and H 2 - diatomic molecules in the temperature range 1500-15000 K. Calculations are performed for H 2 (X, B, C), OH(X, A, B), H 2 + (X), OH + (X, a, A, b, c), H 2 - (X) and OH - (X) electronic states for which Dunham coefficients are available. Rate coefficients are calculated from WTCS assuming Maxwellian energy distribution functions for electrons and heavy particles. One and 2 temperatures (θ e and θ g respectively for electron and heavy particles kinetic temperatures) results are presented and fitting parameters (a, b and c) are given for each reaction rate coefficient: k(θ) a(θ b )exp(-c/θ). (authors)
Impacts of external convection on release rates in metal hydride storage tanks. Paper no. IGEC-1-080
International Nuclear Information System (INIS)
MacDonald, B.; Rowe, A.; Tomlinson, J.; Ho, J.
2005-01-01
Reversible metal hydrides can be used to store hydrogen at relatively low pressures, with very high volumetric density. The rate hydrogen can be drawn from a given tank is strongly influenced by the rate heat can be transferred to the reaction zone. Because of this, enhancing and controlling heat transfer is a key area of research in the development of metal hydride storage tanks. In this work, the impacts of external convection resistance on hydrogen release rates are examined. A one-dimensional resistive analysis determines the thermal resistances in the system based on one case where no external heat transfer enhancements are used, and a second case where external fins are used. A two-dimensional, transient model, developed in FEMLAB, is used to determine the impact of the external fins on the mass flow rate of hydrogen in more detail. For the particular metal hydride alloy (LaNi 4.8 Sn 0.2 ) and tank geometry studied, it was found that the fins have a large impact on the hydrogen flow rate during the initial stages of desorption. The flow rate with no fins is only 20% of the flow rate with fins for a full tank, 57% when the tank is 33% full, and 74% when the tank is 5% full. As the reaction proceeds, the resistance of the metal hydride alloy within the tank increases and becomes dominant. Therefore, the impact of the fins becomes less significant as the tank empties. (author)
International Nuclear Information System (INIS)
Bergstroem, U.
1983-05-01
The turnover of radioactive matter entering the biosphere with groundwater has been studied with regard to exposure and doses to critical groups and populations. Two main recipients, a well and a lake, have been considered for the inflow of groundwaterborne nuclides. Mathematical models of a set of coupled ecosystems on regional, intermediate and global levels have been used for calculations of doses. The intermediate system refers to the Baltic Sea. The mathematical treatment of the model is based upon compartment theory with first order kinetics and also includes products in decay chains. The time-dependent exposures have been studied for certain long-lived nuclides of radiological interest in waste from disposed fuel. Dose and dose commitment have been calculated for different episodes for inflow to the biosphere. (author)
Reaction rate estimation of controlled-release antifouling paint binders: Rosin-based systems
DEFF Research Database (Denmark)
Meseguer Yebra, Diego; Kiil, Søren; Dam-Johansen, Kim
2005-01-01
Biofouling on ship hulls is prevented by the use of antifouling (A/F) paints. Typically, sea water soluble rosin or rosin-derivatives are used as the primary means of adjusting the polishing rate of the current chemically active self-polishing paint systems to a suitable value. Previous studies h...
Growth rates and post-release survival of captive neonate timber rattlesnakes Crotalus horridus
Richard N. Conner; D. Craig Rudolph; Daniel Saenz; Richard R. Schaefer; Shirley J. Burgdorf
2003-01-01
The need for conservation and management of rare species is becoming increasingly important as wildlife species and their habitat continue to decline. Translocation of wild captured adults to augment and reintroduce populations has been successfully used for some endangered avian species (see Carrie et al. 1999; Rudolph et al. 1992). In general, success rates for...
Larochelle, Marc R; Zhang, Fang; Ross-Degnan, Dennis; Wharam, J Frank
2015-06-01
In the second half of 2010, abuse-deterrent extended-release oxycodone hydrochloride (OxyContin; Purdue Pharma) was introduced and propoxyphene was withdrawn from the US market. The effect of these pharmaceutical market changes on opioid dispensing and overdose rates is unknown. To evaluate the association between 2 temporally proximate changes in the opioid market and opioid dispensing and overdose rates. Claims from a large national US health insurer were analyzed, using an interrupted time series study design. Participants included an open cohort of 31.3 million commercially insured members aged 18 to 64 years between January 1, 2003, and December 31, 2012, with median follow-up of 20 months (last follow-up, December 31, 2012). Introduction of abuse-deterrent OxyContin (resistant to crushing or dissolving) on August 9, 2010, and market withdrawal of propoxyphene on November 19, 2010. Standardized opioid dispensing rates and prescription opioid and heroin overdose rates were the primary outcomes. We used segmented regression to analyze changes in outcomes from 30 quarters before to 8 quarters after the 2 interventions. Two years after the opioid market changes, total opioid dispensing decreased by 19% from the expected rate (absolute change, -32.2 mg morphine-equivalent dose per member per quarter [95% CI, -38.1 to -26.3]). By opioid subtype, the absolute change in dispensing by milligrams of morphine-equivalent dose per member per quarter at 2 years was -11.3 (95% CI, -12.4 to -10.1) for extended-release oxycodone, 3.26 (95% CI, 1.40 to 5.12) for other long-acting opioids, -8.19 (95% CI, -9.30 to -7.08) for propoxyphene, and -16.2 (95% CI, -18.8 to -13.5) for other immediate-release opioids. Two years after the market changes, the estimated overdose rate attributed to prescription opioids decreased by 20% (absolute change, -1.10 per 100,000 members per quarter [95% CI, -1.47 to -0.74]), but heroin overdose increased by 23% (absolute change, 0.26 per 100
International Nuclear Information System (INIS)
Iijima, Toshinori; Shiraishi, Tadao
1979-10-01
For environmental doses from routine releases of LWRs effluents to meet the Criterion 'As Low As is Practicable (ALAP)', Japan Atomic Energy Commission (JAEC) established a series of guides, the first for 'Dose Objectives' (May 1975), the second for models and parameters for calculating the environmental doses to compare with the 'Dose Objectives' (September 1976), and the third providing onsite meteorological programs, statistics of the data obtained and atmospheric dispersion models (June 1977). JAERI has developed a computer code, designated as ANDOSE, for calculating annual releases of radioactive gaseous and liquid effluents and, then, total body doses and thyroid doses to individuals around sites on the basis of these guides. The total body doses are from radioactive noble gases as well as from radioactive materials taken with marine food. For the calculation of thyroid doses are taken into account exposure pathways via inhalation and ingestion of leafy vegetables, cow's milk and marine food. The age-specific thyroid doses are evaluated. The doses are summed up when multisource or multisite conditions need to be evaluated (Nuclear Safety Bureau's requirement). In the present report, are described source-term models, environmental transport models and dose models used in the code, of which most are provided in the guides but some are complemented by the authors, the functions of ANDOSE and the manual for users of the code. The program lists and the latter two guides mentioned above are included in the appendices. (author)
Point kernel technique for calculating dose rates due to cobalt-60 hot particles
International Nuclear Information System (INIS)
Thornhill, M.J.; McCarthy, J.T.; Morrissette, R.R.; Leach, B.N.
1989-01-01
This paper reports on a computer code called BETA that has been developed by health physicists at the Vermont Yankee Nuclear Power Station which accounts for the mass and size of hot particles of Cobalt-60, and therefore corrects the Loevinger-based dose calculation for self-absorption
42 CFR 419.32 - Calculation of prospective payment rates for hospital outpatient services.
2010-10-01
... outpatient services furnished in 1999 would have equaled the base expenditure target calculated in § 419.30... inpatient market basket percentage increase applicable under section 1886(b)(3)(B)(iii) of the Act reduced... 1, 2001 and before April 1, 2001, by the hospital inpatient market basket percentage increase...
Data and software for calculating neutron spectra from measured reaction rates
International Nuclear Information System (INIS)
Berzonis, M.A.; Bonbars, Kh.Ya.
1981-01-01
The information system SAIPS is presented, which allows the automated calculation of neutron spectra and the use of cross section libraries on EC type computers. The following programmes can be applied: SAND II, WINDOWS, CRYSTAL BALL, RFSP JUEL, etc. The system includes both cross section libraries established by means of the code mentioned and libraries recommended by several laboratories. (author)
Window Energy Rating System and Calculation of Energy Performance of Windows
DEFF Research Database (Denmark)
Laustsen, Jacob Birck; Svendsen, Svend
The goal of reducing the energy consumption in buildings is the background for the introduction of an energy rating system of fenestration products in Denmark. The energy rating system requires that producers declare, among other things, the heat loss coefficient, U, and the total solar energy...... development, e.g. when the resulting effects of a reduced frame area are evaluated....
NCLB Implementation Report: State Approaches for Calculating High School Graduation Rates.
Swanson, Christopher B.
This review investigated the state accountability Workbooks provisionally approved and publicly reported by the U.S. Department of Education (DOE) as of June 2003. These documents were obtained from the DOE Web site. This report examines state definitions of high school graduation rates and strategies for constructing graduation rate indicators. A…
International Nuclear Information System (INIS)
Kokoouline, V.; Richardson, W.
2014-01-01
Uncertainties in theoretical calculations may include: • Systematic uncertainty: Due to applicability limits of the chosen model. • Random: Within a model, uncertainties of model parameters result in uncertainties of final results (such as cross sections). • If uncertainties of experimental and theoretical data are known, for the purpose of data evaluation (to produce recommended data), one should combine two data sets to produce the best guess data with the smallest possible uncertainty. In many situations, it is possible to assess the accuracy of theoretical calculations because theoretical models usually rely on parameters that are uncertain, but not completely random, i.e. the uncertainties of the parameters of the models are approximately known. If there are one or several such parameters with corresponding uncertainties, even if some or all parameters are correlated, the above approach gives a conceptually simple way to calculate uncertainties of final cross sections (uncertainty propagation). Numerically, the statistical approach to the uncertainty propagation could be computationally expensive. However, in situations, where uncertainties are considered to be as important as the actual cross sections (for data validation or benchmark calculations, for example), such a numerical effort is justified. Having data from different sources (say, from theory and experiment), a systematic statistical approach allows one to compare the data and produce “unbiased” evaluated data with improved uncertainties, if uncertainties of initial data from different sources are available. Without uncertainties, the data evaluation/validation becomes impossible. This is the reason why theoreticians should assess the accuracy of their calculations in one way or another. A statistical and systematic approach, similar to the described above, is preferable.
DEFF Research Database (Denmark)
Blasques, José Pedro Albergaria Amaral; Bitsche, Robert
2015-01-01
This paper proposes a novel, efficient, and accurate framework for fracture analysis of beam structures with longitudinal cracks. The three-dimensional local stress field is determined using a high-fidelity beam model incorporating a finite element based cross section analysis tool. The Virtual...... Crack Closure Technique is used for computation of strain energy release rates. The devised framework was employed for analysis of cracks in beams with different cross section geometries. The results show that the accuracy of the proposed method is comparable to that of conventional three......-dimensional solid finite element models while using only a fraction of the computation time....
DEFF Research Database (Denmark)
Eder, Martin Alexander; Bitsche, Robert; Belloni, Federico
2015-01-01
Most wind turbine rotor blades comprise several adhesively connected sub-components typically made from glass fibre reinforced polymer composite materials. It is a well-known fact that wind turbine blades are prone to fail in their adhesive joints. However, owing to the complexity...... of their structural behaviour, little is known about the root causes of adhesive joint failure. This paper investigates the effects of geometrical non-linearity on energy release rates (ERRs) of transversely oriented cracks present in the adhesive joints of a wind turbine rotor blade. Utilising a computationally...
DEFF Research Database (Denmark)
Stevens, Thomas; Lu, HY
2009-01-01
Understanding loess sedimentation rates is crucial for constraining past atmospheric dust dynamics, regional climatic change and local depositional environments. However, the derivation of loess sedimentation rates is complicated by the lack of available methods for independent calculation......) the influences on sediment grain-size and accumulation; and (ii) their relationship through time and across the depositional region. This uncertainty has led to the widespread use of assumptions concerning the relationship between sedimentation rate and grain-size in order to derive age models and climate...... reconstructions. To address this uncertainty, detailed independent age models, based on optically stimulated luminescence dating, undertaken at 10 to 40 cm intervals at five sections across the Loess Plateau in China, have been used to calculate sedimentation rates and make comparisons with grain-size changes...
Wright, J. D.; Schaller, M. F.
2012-12-01
The Paleocene/Eocene Thermal Maximum (PETM) Carbon Isotope Excursion (CIE) is linked to benthic foraminiferal extinction and excursion taxa in planktonic foraminifera and calcareous nannofossils. Previous studies have used integrated bio-magneto-stratigraphies, cycle counting, and extraterrestrial 3He accumulation rates to produce a range of estimates for the duration of the initial onset of the PETM CIE between 750 years to 30 kyr. Durations for the total release time (onset to initiation of recovery) range from 45 to 95 kyr. Uncertainty in the timing of the onset of the PETM CIE prevents the identification of a causal mechanism, and hence understanding the biological responses. Recent work on the Paleocene/Eocene Marlboro Clay has unveiled the presence of regular couplets (~2 cm) expressed in multiple cores and exposures throughout the Atlantic Coastal Plain. Specifically, the Millville and newly recovered Wilson Lake B cores contain 750 and 660 layers through the CIE, respectively. These couplets have corresponding oxygen stable isotope cycles, arguing for a climatic origin. Orbital and millennial periodicities are far too long to explain the ~750 layers identified in the Millville core. Seasonal insolation is the only regular climate cycle that can plausibly account for the observed δ18O amplitudes (~1‰, with some cycles up to 2‰) and layer counts. Seasonal freshwater input can also augment the cyclic oscillations in δ18O, but the majority of the variability is most plausibly ascribed to temperature. Wilson Lake B and Millville have total δ13C excursions of -5 and -4.5‰ respectively, as well as highly expanded sections of the PETM CIE. In the Millville core, high-resolution, bulk stable isotope records show a 3.5‰ δ13C decrease over 12 layers across the PETM CIE onset. Concomitant with this δ13C decrease is a sharp drop in CaCO3. Decreases in both proxies require a large, sudden release of isotopically light carbon. The couplet chronology indicates
Iyer, Karthik; Schmid, Daniel
2016-04-01
Evidence of mass extinction events in conjunction with climate change occur throughout the geological record and may be accompanied by pronounced negative carbon isotope excursions. The processes that trigger such globally destructive changes are still under considerable debate. These include mechanisms such as poisoning from trace metals released during large volcanic eruptions (Vogt, 1972), CO2 released from lava degassing during the formation of Large Igneous Provinces (LIPs) (Courtillot and Renne, 2003) and CH4 release during the destabilization of sub-seafloor methane (Dickens et al., 1995), to name a few. Thermogenic methane derived from contact metamorphism associated with magma emplacement and cooling in sedimentary basins has been recently gaining considerable attention as a potential mechanism that may have triggered global climate events in the past (e.g. Svensen and Jamtveit, 2010). The discovery of hydrothermal vent complexes that are spatially associated with such basins also supports the discharge of greenhouse gases into the atmosphere (e.g. Jamtveit et al., 2004; Planke et al., 2005; Svensen et al., 2006). A previous study that investigated this process using a fluid flow model (Iyer et al., 2013) suggested that although hydrothermal plume formation resulting from sill emplacement may indeed release large quantities of methane at the surface, the rate at which this methane is released into the atmosphere is too slow to trigger, by itself, some of the negative δ13C excursions observed in the fossil record over short time scales observed in the fossil record. Here, we reinvestigate the rates of gas release during sill emplacement in a case study from the Harstad Basin off-shore Norway with a special emphasis on vent formation. The presented study is based on a seismic line that crosses multiple sill structures emplaced around 55 Ma within the Lower Cretaceous sediments. A single well-defined vent complex is interpreted above the termination of the
International Nuclear Information System (INIS)
1989-09-01
This Standard provides guidelines and a methodology for calculating effective doses and thyroid doses to people (either individually or collectively) in the path of airborne radioactive material released from a nuclear facility following a hypothetical accident. The specific radionuclides considered in the Standard are those associated with substances having the greatest potential for becoming airborne in reactor accidents (eg, tritium (HTO), noble gases and their daughters (Kr-Rb, Xe-Cs), and radioiodines (I)); and certain radioactive particulates (eg, Cs, Ru, Sr, Te) that may become airborne under exceptional circumstances
The problem of reactivity and reaction-rate calculations for mixed graphite lattices
International Nuclear Information System (INIS)
Pitcher, H.H.W.
1963-05-01
The dependence of reactor physics quantities, such as η f and Pu239/U235 fission ratio, in a single cell on the environment of the cell, and the relationship of the reactivity of a mixed lattice to the reactivity of its components, in graphite-moderated reactors are investigated. In a particular case, a mixed lattice fuelled with uranium at 0 and 3000 MWD/Te showed at 8 cm. pitch a small but appreciable change (∼ 1%) in cell quantities, and at 25 cm. pitch a smaller change. It is found that the present method of calculating lattice reactivity, ignoring intercell effects, is probably adequate for standard-pitch metal-fuelled graphite-moderated systems. More general mixed-lattice systems, particularly if accurate values of cell quantities are required, may need special calculation techniques; these are discussed, and techniques adequate for most systems are presented. (author)
International Nuclear Information System (INIS)
Esteve Sanchez, S.; Martinez Albaladejo, M.; Garcia Fuentes, J. D.; Bejar Navarro, M. J.; Capuz Suarez, B.; Moris de Pablos, R.; Colmenares Fernandez, R.
2015-01-01
We assessed the reliability of the program with 80 patients in the usual points of prescription of each pathology. The average error of the calculation points is less than 0.3% in 95% of cases, finding the major differences in the axes of the applicators (maximum error -0.798%). The program has proved effective previously testing him with erroneous dosimetry. Thanks to the implementation of this program is achieved by the calculation of the dose and part of the process of quality assurance program in a few minutes, highlighting the case of HDR prostate due to having a limited time. Having separate data sheet allows each institution to its protocols modify parameters. (Author)
A fracture- mechanics calculation of crack growth rate for a gas turbine blade
International Nuclear Information System (INIS)
Mirzaei, M.; Karimi, R.
2002-01-01
The existence of thermo-mechanical stresses, due to the frequent start-ups and shutdowns of gas turbines. Combined with high working temperatures may cause creep and fatigue failure of the blades. This paper describes a fracture-mechanics life assessment of a gas turbine blade. Initially, the distributions of thermal and mechanical stresses were obtained by using the finite element method. Accordingly; the crack modeling was performed in a high stress region at the suction side surface of the blade. Several crack growth increments were observed and the related crack tip parameters were calculated. Finally; the creep-fatigue crack growth in each cycle was calculated and the total number of start-stop cycles was determined
International Nuclear Information System (INIS)
Phillips, R.L.; London, E.D.; Links, J.M.; Cascella, N.G.
1990-01-01
A program was developed to align positron emission tomography images from multiple studies on the same subject. The program allowed alignment of two images with a fineness of one-tenth the width of a pixel. The indications and effects of misalignment were assessed in eight subjects from a placebo-controlled double-blind crossover study on the effects of cocaine on regional cerebral metabolic rates for glucose. Visual examination of a difference image provided a sensitive and accurate tool for assessing image alignment. Image alignment within 2.8 mm was essential to reduce variability of measured cerebral metabolic rates for glucose. Misalignment by this amount introduced errors on the order of 20% in the computed metabolic rate for glucose. These errors propagate to the difference between metabolic rates for a subject measured in basal versus perturbed states
Automated Discovery of New Chemical Reactions and Accurate Calculation of Their Rates
2015-06-02
chemistry calculations are run. The product matrices P are obtained and converted to block structure by simple linear algebra operations...in the system, i.e. 0 , =∑ ji ija Usually in elementary reactions |aij|ɛ since the change by two implies a significant chemical process, for...instance, formation or rupture of a double bond in a single elementary step. After applying the reaction matrix A, the product matrix P can then be
International Nuclear Information System (INIS)
Li Chunjuan; Liu Yi'na; Zhang Weihua; Wang Zhiqiang
2014-01-01
The manganese bath method for measuring the neutron emission rate of radionuclide sources requires corrections to be made for emitted neutrons which are not captured by manganese nuclei. The Monte Carlo particle transport code MCNP was used to simulate the manganese bath system of the standards for the measurement of neutron source intensity. The correction factors were calculated and the reliability of the model was demonstrated through the key comparison for the radionuclide neutron source emission rate measurements organized by BIPM. The uncertainties in the calculated values were evaluated by considering the sensitivities to the solution density, the density of the radioactive material, the positioning of the source, the radius of the bath, and the interaction cross-sections. A new method for the evaluation of the uncertainties in Monte Carlo calculation was given. (authors)
International Nuclear Information System (INIS)
Grebner, H.; Hoefler, A.; Hunger, H.
1991-01-01
In this paper calculations to experiments on leak opening and leak rates of piping components are presented. The experiments are performed at the HDR-facility at Karlstein/Germany and up to now straight pipes and pipe branches were considered. Numerical and experimental results are compared. (author)
International Nuclear Information System (INIS)
Cota, P.L.
1987-01-01
The used methods for calculating the rate and area of sedimentation are based in techniques of graphical resolution. The solution of the problem by a mathematical resolution, using computational methods, is more fast and more accuracy. The comparison between the results from this methods and the conventional method is shown. (E.G.) [pt
Feenstra, K Anton; Peter, Christine; Scheek, Ruud M; van Gunsteren, Wilfred F; Mark, Alan E
Three methods for calculating nuclear magnetic resonance cross-relaxation rates from molecular dynamics simulations of small flexible molecules have been compared in terms of their ability to reproduce relaxation data obtained experimentally and to produce consistent descriptions of the system. The
International Nuclear Information System (INIS)
Crabol, B.; Romeo, E.; Nester, K.
1992-01-01
In case of an accident in a nuclear power plant near the French-German border different schemes for dispersion calculations in both countries will currently be applied. An intercomparison of these schemes initiated from the German-French Commission for the safety of nuclear installations (DFK) revealed in some meteorological situations large differences in the resulting concentrations for radionuclides. An ad hoc working group was installed by the DFK with the mandate to analyse the reasons for the different model results and also to consider new theoretical concepts. The working group has agreed to apply a Gaussian puff model for emergency response calculations. The results of the model based on turbulence parameterization via similarity approach or spectral theory - have been compared with tracer experiments for different emission heights and atmospheric stability regimes. As a reference the old modelling approaches have been included in the study. The simulations with the similarity approach and the spectral theory show a slightly better agreement to the measured concentration data than the schemes used in the past. Instead of diffusion categories both new approaches allow a continuous characterization of the atmospheric dispersion conditions. Because the spectral approach incorporates the sampling time of the meteorological data as an adjustable parameter thereby offering the possibility to adjust the dispersion model to different emission scenarios this turbulence parameterization scheme will be foreseen as the basis for a joint French-German puff model
Calculation of astrophysical S-factor and reaction rate in 12C(p, γ)13N reaction
Moghadasi, A.; Sadeghi, H.; Pourimani, R.
2018-02-01
The 12C(p, γ)13N reaction is the first process in the CNO cycle. Also it is a source of low-energy solar neutrinos in various neutrino experiments. Therefore, it is of high interest to gain data of the astrophysical S-factor in low energies. By applying Faddeev's method, we calculated wave functions for the bound state of 13N. Then the cross sections for resonance and non-resonance were calculated through using Breit-Wigner and direct capture cross section formulae, respectively. After that, we calculated the total S-factor and compared it with previous experimental data, revealing a good agreement altogether. Then, we extrapolated the S-factor in zero energy and the result was 1.32 ± 0.19 (keV.b). In the end, we calculated reaction rate and compared it with NACRE data.
Optimization of detector size and scan rate for beta/gamma material release surveys
International Nuclear Information System (INIS)
Bishop, R.V.
1993-01-01
DOE facilities are required to offer for sale to the public items of salvageable value when they are no longer required by the facilities. These items have to be surveyed to ensure radioactive contamination levels do not exceed the values listed in DOE Order 5400.5. Most facilities use portable contamination monitoring.equipment with probe areas between 20 and 100 cm 2 to check for fixed contamination. This procedure is very labor intensive and results in survey costs that often exceed the costs recovered from selling the items. A solution would be to use large area (> 100 cm 2 ) detectors to find and quantify contamination. Large area scintillation detectors that can be used for beta and alpha detection simultaneously are becoming available commercially. Combining these with a rate meter that can differentiate between alpha and beta events can result in a survey that takes considerably less time to do and will save a proportional amount of money in doing so. The use and limitations of this combination of detectors and rate meters will be discussed
International Nuclear Information System (INIS)
1991-04-01
This standard provides guidelines and a methodology for calculating effective doses and thyroid doses to people (either individually or collectively) in the path of airborne radioactive material released from a nuclear facility following a hypothetical accident. The radionuclides considered are those associated with substances having the greatest potential for becoming airborne in reactor accidents: tritium (HTO), noble gases and their daughters, radioiodines, and certain radioactive particulates (Cs, Ru, Sr, Te). The standard focuses on the calculation of radiation doses for external exposures from radioactive material in the cloud; internal exposures for inhalation of radioactive material in the cloud and skin penetration of tritium; and external exposures from radionuclides deposited on the ground. It uses as modified Gaussian plume model to evaluate the time-integrated concentration downwind. (52 refs., 12 tabs., 21 figs.)
Liu, Fei-Xiang; Long, Ji-Dong; Zheng, Le; Dong, Pan; Li, Chen; Chen, Wei
2018-02-01
The ionization rate of the released deuterium from a metal deuteride cathode in vacuum arc discharges is investigated by both experiments and modeling analysis. Experimental results show that the deuterium ionization rate increases from 2% to 30% with the increasing arc current in the range of 2-100 A. Thus the full ionization assumption, as is widely used in arc plasma simulations, is not satisfied for the released deuterium at low discharge current. According to the modeling results, the neutral-to-ion conversion efficiency for the deuterium traveling across the cathodic spot region can be significantly less than one, due to the fast plasma expansion and rarefaction in the vacuum. In addition, the model also reveals that, unlike the metal atoms which are mainly ionized in the sheath region and flow back to the cathode, the deuterium ionization primarily occurs in the quasi-neutral region and moves towards the anode. Consequently, the cathodic sheath layer acts like a filter that increases the deuterium fraction beyond the sheath region.
Sokal, Agnieszka; Pindelska, Edyta; Szeleszczuk, Lukasz; Kolodziejski, Waclaw
2017-04-30
The aim of this study was to evaluate the stability and solubility of the polymorphic forms of the ethenzamide (ET) - gentisic acid (GA) cocrystals during standard technological processes leading to tablet formation, such as compression and excipient addition. In this work two polymorphic forms of pharmaceutical cocrystals (ETGA) were characterized by 13 C and 15 N solid-state nuclear magnetic resonance and Fourier transformed infrared spectroscopy. Spectroscopic studies were supported by gauge including projector augmented wave (GIPAW) calculations of chemical shielding constants.Polymorphs of cocrystals were easily identified and characterized on the basis of solid-state spectroscopic studies. ETGA cocrystals behaviour during direct compressionand tabletting with excipient addition were tested. In order to choose the best tablet composition with suitable properties for the pharmaceutical industry dissolution profile studies of tablets containing polymorphic forms of cocrystals with selected excipients were carried out. Copyright © 2017. Published by Elsevier B.V.
Calculation on cosmic-ray muon exposure rate in non-walled concrete buildings
International Nuclear Information System (INIS)
Fujitaka, Kazunobu; Abe, Siro
1984-01-01
Computer simulations on the exposure indoors from cosmic ray muons were practiced in the framework of non-scattering and non-cascade assumptions. The model buildings were two-dimensional, rectangular, and were made of a normal concrete. A stratified structure was assumed in each building, where no mezzanine was considered. Walls were not taken into account yet. The distributions of the exposure rates in 26-story buildings were illustrated in contour maps for various sets of parameters. All of them gave basically archlike patterns. Analyses of the results showed that the exposure rate is affected most largely by the floor board thickness. The ceiling height would be an insignificant factor for short buildings. The min/max ratio of the muon exposure rate in a moderate size building was estimated to be more than 0.7. (author)
Status of the fuel stress and failure rate calculations at KFA
International Nuclear Information System (INIS)
Bongartz, K.
1980-11-01
In this report a new model for calculating stresses in the SiC layer of TRISO coated particles is presented. The gain in computer time with respect to the Walther model used up to now is a factor of 100. The restrictions of this model are - application is only possible to TRISO particles and not BISO which can be handled with the Walther model as well, the SiC layer is regarded as rigid: in fact, its Young's modulus is higher by a factor of 10 as compared to that of the Pyrocarbon layers. (orig.) [de
Multiconfiguration Dirac-Hartree-Fock calculations of energy levels and radiative rates of Fe VII
Li, Yang; Xu, Xiaokai; Li, Bowen; Jönsson, Per; Chen, Ximeng
2018-06-01
Detailed calculations are performed for 134 fine-structure levels of the 3p63d2, 3p63d4s, 3p53d3 and 3p63d4p configurations in Fe VII using the multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) methods. Important electron correlation effects are systematically accounted for through active space (AS) expansions. Our results compare well with experimental measurements, emphasizing the importance of a careful treatment of electron correlation, and provide some missing data in the NIST atomic database. The data obtained are expected to be useful in astrophysical applications, particularly for the research of the solar coronal plasma.
Shell-model calculations of beta-decay rates for s- and r-process nucleosyntheses
International Nuclear Information System (INIS)
Takahashi, K.; Mathews, G.J.; Bloom, S.D.
1985-01-01
Examples of large-basis shell-model calculations of Gamow-Teller β-decay properties of specific interest in the astrophysical s- and r- processes are presented. Numerical results are given for: (1) the GT-matrix elements for the excited state decays of the unstable s-process nucleus 99 Tc; and (2) the GT-strength function for the neutron-rich nucleus 130 Cd, which lies on the r-process path. The results are discussed in conjunction with the astrophysics problems. 23 refs., 3 figs
The inclusion of shadowing effect in the reaction-rates calculation
International Nuclear Information System (INIS)
Monteiro, M.A.M.
1990-03-01
A method for the Resonance Integral calculation in the fuel and moderator regions is presented including the Shadowing effect. This effect appears due to the presence of several fuel rods in a infinite moderator region. The method is based on the approximations to the J (ζ, β) function and theirs partial derivatives in relation to β. The dependence of the Resonance Integral in the J (ζ, β) comes from the rational approximation to the neutron escape probability. The final results are obtained in a very simple and fast way, and show the good accuracy of the method. (author)
Variational RRKM calculation of thermal rate constant for C–H bond fission reaction of nitro methane
Directory of Open Access Journals (Sweden)
Afshin Taghva Manesh
2017-02-01
Full Text Available The present work provides quantitative results for the rate constants of unimolecular C–H bond fission reactions in the nitro methane at elevated temperatures up to 2000 K. In fact, there are three different hydrogen atoms in the nitro methane. The potential energy surface for each C–H bond fission reaction of nitro methane was investigated by ab initio calculations. The geometry and vibrational frequencies of the species involved in this process were optimized at the MP2 level of theory, using the cc-pvdz basis set. Since C–H bond fission channel is a barrierless reaction, we have used variational RRKM theory to predict rate coefficients. By means of calculated rate coefficients at different temperatures, the Arrhenius expression of the channel over the temperature range of 100–2000 K is k(T = 5.9E19∗exp(−56274.6/T.
User's guide to SERICPAC: A computer program for calculating electric-utility avoided costs rates
Energy Technology Data Exchange (ETDEWEB)
Wirtshafter, R.; Abrash, M.; Koved, M.; Feldman, S.
1982-05-01
SERICPAC is a computer program developed to calculate average avoided cost rates for decentralized power producers and cogenerators that sell electricity to electric utilities. SERICPAC works in tandem with SERICOST, a program to calculate avoided costs, and determines the appropriate rates for buying and selling of electricity from electric utilities to qualifying facilities (QF) as stipulated under Section 210 of PURA. SERICPAC contains simulation models for eight technologies including wind, hydro, biogas, and cogeneration. The simulations are converted in a diversified utility production which can be either gross production or net production, which accounts for an internal electricity usage by the QF. The program allows for adjustments to the production to be made for scheduled and forced outages. The final output of the model is a technology-specific average annual rate. The report contains a description of the technologies and the simulations as well as complete user's guide to SERICPAC.
Energy Technology Data Exchange (ETDEWEB)
Eichler, B.; Neuhausen, J
2004-06-01
An analysis of literature data for the thermochemical constants of polonium reveals considerable discrepancies in the relations of these data among each other as well as in their expected trends within the chalcogen group. This fact hinders a reliable assessment of possible reaction paths for the release of polonium from a liquid lead-bismuth spallation target. In this work an attempt is made to construct a coherent data set for the thermochemical properties of polonium and some of its compounds that are of particular importance with respect to the behaviour of polonium in a liquid Pb-Bi target. This data set is based on extrapolations using general trends throughout the periodic table and, in particular, within the chalcogen group. Consequently, no high accuracy should be attributed to the derived data set. However, the data set derived in this work is consistent with definitely known experimental data. Furthermore, it complies with the general trends of physicochemical properties within the chalcogen group. Finally, well known relations between thermochemical quantities are fulfilled by the data derived in this work. Thus, given the lack of accurate experimental data it can be regarded as best available data. Thermochemical constants of polonium hydride, lead polonide and polonium dioxide are derived based on extrapolative procedures. Furthermore, the possibility of formation of the gaseous intermetallic molecule BiPo, which has been omitted from discussion up to now, is investigated. From the derived thermochemical data the equilibrium constants of formation, release and dissociation reactions are calculated for different polonium containing species. Furthermore equilibrium constants are determined for the reaction of lead polonide and polonium dioxide with hydrogen, water vapour and the target components lead and bismuth. The most probable release pathways are discussed. From thermochemical evaluations polonium is expected to be released from liquid lead
Directory of Open Access Journals (Sweden)
Mohammed S. Al-Jawad
2017-11-01
Full Text Available Multilateral wells require a sophisticated type of well model to be applied in reservoir simulators to represent them. The model must be able to determine the flow rate of each fluid and the pressure throughout the well. The production rate calculations are very important because they give an indication about some main issues associated with multi-lateral wells such as one branch may produce water or gas before others, no production rate from one branch, and selecting the best location of a new branch for development process easily. This paper states the way to calculate production rate of each branch of a multilateral well-using multi-segment well model. The pressure behaviour of each branch is simulated dependent on knowing its production rate. This model has divided a multi-lateral well into an arbitrary number of segments depending on the required degree of accuracy and run time of the simulator. The model implemented on a field example (multi-lateral well HF-65ML in Halfaya Oil Field/Mishrif formation. The production rate and pressure behaviour of each branch are simulated during the producing interval of the multilateral well. The conclusion is that production rate of the main branch is slightly larger than a lateral branch.
Calculating second derivatives of population growth rates for ecology and evolution
Shyu, E.; Caswell, H.
2014-01-01
Second derivatives of the population growth rate measure the curvature of its response to demographic, physiological or environmental parameters. The second derivatives quantify the response of sensitivity results to perturbations, provide a classification of types of selection and provide one way
International Nuclear Information System (INIS)
Nabi, Jameel-Un
2010-01-01
An accurate estimate of the neutrino cooling rates is required in order to study the various stages of stellar evolution of massive stars. Neutrino losses from proto-neutron stars play a crucial role in deciding whether these stars would be crushed into black holes or explode as supernovae. Both pure leptonic and weak-interaction processes contribute to the neutrino energy losses in stellar matter. At low temperatures and densities, the characteristics of the early phase of presupernova evolution, cooling through neutrinos produced via the weak interaction, are important. Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has recently been used with success for the calculation of stellar weak-interaction rates of fp-shell nuclide. The lepton-to-baryon ratio (Y e ) during early phases of stellar evolution of massive stars changes substantially, mainly due to electron captures on 56 Ni. The stellar matter is transparent to the neutrinos produced during the presupernova evolution of massive stars. These neutrinos escape the site and assist the stellar core in maintaining a lower entropy. Here, an expanded calculation of weak-interaction-mediated neutrino and antineutrino cooling rates due to 56 Ni in stellar matter using the pn-QRPA theory is presented. This detailed scale is appropriate for interpolation purposes and is of greater utility for simulation codes. The calculated rates are compared with earlier calculations. During the relevant temperature and density regions of stellar matter the reported rates show few differences compared with the shell model rates and might contribute in fine-tuning of the lepton-to-baryon ratio during the presupernova phases of stellar evolution of massive stars.
International Nuclear Information System (INIS)
Maul, P.R.
1982-03-01
Simple methods are described which enable assessments to be made of exposure rates to individuals arising from the release of activity into an estuary or sea. These methods are based in the main on those employed by the Ministry of Agriculture Fisheries and Food together with models developed by the author. The exposure routes considered are the ingestion of seafood and external exposure from β and γ emitters arising from occupancy over contaminated sediments or beaches and the handling of fishing gear. These routes are generally the most important, but for any chosen site it will also be necessary to determine whether any other exposure routes are significant. (author)
International Nuclear Information System (INIS)
Maul, P.R.
1982-11-01
Simple methods are described which enable assessments to be made of exposure rates to individuals arising from the release of activity into an estuary or sea. These methods are based in the main on those employed by the Ministry of Agriculture Fisheries and Food together with models developed by the author. The exposure routes considered are the ingestion of seafood and external exposure from ν and ν emitters arising from occupancy over contaminated sediments or beaches and the handling of fishing gear. These routes are generally the most important, but for any chosen site it will also be necessary to determine whether any other exposure routes are significant. (author)
Calculations of the Auger deexcitation rate of dtμ within the muonic quasimolecule (dtμ)dee
Armour, E. A. G.; Lewis, D. M.; Hara, S.
1992-12-01
A key process in muon-catalyzed fusion is the deexcitation of dtμ within the resonant muonic quasimolecule (dtμ)dee, by emission of an Auger electron. The dtμ in the quasimolecule is initially in a weakly bound excited state with J=1 and v=1. Calculations are carried out of the rate of the dominant transition to the state with J=0 and v=1. Use is made of the dipole matrix element obtained for this transition by Scrinzi and Szalewicz [Phys. Rev. A 39, 2855 (1989)]. Full account is taken of the molecular nature of the quasimolecule. The continuum electronic wave functions for the Auger electron for all four contributing symmetries, i.e., Σ+g, Σ+u, Πu, and Πg, are first obtained by a two-center Coulomb calculation and a static-exchange calculation, extended to include dipole polarization. Comparison is then made with the results of a calculation in which the Σ+μ and Πu wave functions are obtained as in a previous paper by Armour and Lewis [J. Phys. B 23, L25 (1990)] and the Σ+g and Πg wave functions are obtained by the Kohn method. There are significant differences between the contributions from the individual symmetries, but the overall values for the deexcitation rate are all of the same order of magnitude as the results of earlier calculations.
Bi, Ran; Liu, Peng
2016-03-31
RNA-Sequencing (RNA-seq) experiments have been popularly applied to transcriptome studies in recent years. Such experiments are still relatively costly. As a result, RNA-seq experiments often employ a small number of replicates. Power analysis and sample size calculation are challenging in the context of differential expression analysis with RNA-seq data. One challenge is that there are no closed-form formulae to calculate power for the popularly applied tests for differential expression analysis. In addition, false discovery rate (FDR), instead of family-wise type I error rate, is controlled for the multiple testing error in RNA-seq data analysis. So far, there are very few proposals on sample size calculation for RNA-seq experiments. In this paper, we propose a procedure for sample size calculation while controlling FDR for RNA-seq experimental design. Our procedure is based on the weighted linear model analysis facilitated by the voom method which has been shown to have competitive performance in terms of power and FDR control for RNA-seq differential expression analysis. We derive a method that approximates the average power across the differentially expressed genes, and then calculate the sample size to achieve a desired average power while controlling FDR. Simulation results demonstrate that the actual power of several popularly applied tests for differential expression is achieved and is close to the desired power for RNA-seq data with sample size calculated based on our method. Our proposed method provides an efficient algorithm to calculate sample size while controlling FDR for RNA-seq experimental design. We also provide an R package ssizeRNA that implements our proposed method and can be downloaded from the Comprehensive R Archive Network ( http://cran.r-project.org ).
International Nuclear Information System (INIS)
Bleher, M; Stoehlker, U.
2003-01-01
For the surveillance of environmental radioactivity, the German measuring network of BfS consists of more than 2000 stations where the ambient gamma dose rate is continuously measured. This network is a helpful tool to detect and localise enhanced environmental contamination from artificial radionuclides. The threshold for early warning is so low, that already an additional dose rate contribution of 0,07 μGy/h is detectable. However, this threshold is frequently exceeded due to precipitation events caused by washout of natural activity in air. Therefore, the precipitation radar system of the German Weather Service provides valuable information on the problem, whether the increase of the ambient dose rate is due to natural or man-made events. In case of an accidental release, the data of this radar system show small area precipitation events and potential local hot spots not detected by the measuring network. For the phase of cloud passage, the ambient dose rate measuring network provides a reliable database for the evaluation of the current situation and its further development. It is possible to compare measured data for dose rate with derived intervention levels for countermeasures like ''sheltering''. Thus, critical regions can be identified and it is possible to verify implemented countermeasures. During and after this phase of cloud passage the measured data of the monitoring network help to adapt the results of the national decision support systems PARK and RODOS. Therefore, it is necessary to derive the actual additional contribution to the ambient dose rate. Map representations of measured dose rate are rapidly available and helpful to optimise measurement strategies of mobile systems and collection strategies for samples of agricultural products. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Halama, Arthur; Kamerdzhiev, Vsevolod; Boehme, Christian; Srinivasan, Sudharsan [Forschungszentrum Juelich, IKP-4 (Germany)
2016-07-01
The institute of Nuclear Physics 4(IKP-4) of the Research Center Juelich (FZJ) is in charge of building and commissioning the High Energy Storage Ring (HESR) within the international Facility for Antiproton and Ion Research (FAIR) at Darmstadt. Simulations and numerical calculations were performed to characterize the initial beam position pickup design. Capacitive couplings of the electrodes and the behavior of the electrical equivalent circuit were investigated. This made room for changes to the design and performance increase. A prototype of the BPM pickup was constructed and tested on a dedicated test bench. Preliminary results will be presented. In order to gain higher signal levels and higher sensitivity, another suggested design was characterized as well and put into comparison.
Concept for calculating dose rates from activated groundwater at accelerator sites
Prolingheuer, N; Vanderborght, J; Schlögl, B; Nabbi, R; Moormann, R
Licensing of particle accelerators requires the proof that the groundwater outside of the site will not be significantly contaminated by activation products formed below accelerator and target. In order to reduce the effort for this proof, a site independent simplified but conservative method is under development. The conventional approach for calculation of activation of soil and groundwater is shortly described on example of a site close to Forschungszentrum Juelich, Germany. Additionally an updated overview of a data library for partition coefficients for relevant nuclides transported in the aquifer at the site is presented. The approximate model for transport of nuclides with ground water including exemplary results on nuclide concentrations outside of the site boundary and of resulting effective doses is described. Further applications and developments are finally outlined.
International Nuclear Information System (INIS)
Berzonis, M.A.; Bondars, H.Ya.
1981-08-01
A brief description of the SAIPS software and the basic principles of its application is given. SAIPS contains programs needed to unfold spectra, libraries of neutron cross sections and reference spectra, and software for automatic calculation and for system maintenance. SAIPS offers the possibility of determining the reliability of an unfolded neutron spectrum and of planning measurements and calculations by varying different factors: the errors in the reaction rates, the errors in the cross sections used, the detector assembly, the unfolding programs, etc. SAIPS runs on the ES 1022 computer
International Nuclear Information System (INIS)
Pereira, W.S.; Moraes, S.R.; Cavalcante, J.J.V.; Pinto, C.E.C.; Kelecom, A.
2017-01-01
Areas of increased radiation may expose biota to radiation doses greater than the world averages, and depending on the magnitude of the exposure causing biota damage. The region of the municipality of Caldas, MG, BR is considered a region of increased natural radioactivity. The present work aims to evaluate the exposure of biota to natural radionuclides in the region of Caldas, MG. In order to evaluate the biota exposure in the region, the concentrations of the natural radionuclides U nat , 226 Ra, 210 Pb and 232 Th and 228 Ra were evaluated in two species of fishes: lambari (Astymax spp.) And traíra (Hoplias spp.). The dose rates of the analyzed fish were: for Astymax spp of 0.08 μGy d -1 and for Hoplias spp of 0.12 μGy∙d -1 . With these dose rate values no measurable deleterious effects are expected in the species studied
International Nuclear Information System (INIS)
Hicks, H.G.
1981-11-01
This report presents calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from three types of event that deposited detectable radioactivity outside the Nevada Test Site complex, namely, underground nuclear detonations, tests of nuclear rocket engines and tests of nuclear ramjet engines
Directory of Open Access Journals (Sweden)
Virote Pattarajinda
2006-01-01
Full Text Available The objective of this research was to determine the effect of synchronizing the rate of degradation of dietary energy and nitrogen release on growth performance in Brahman beef cattle. Fifteen Brahman cattle, 1.5 years old, with an average initial body weight of 184.8±11.1 kg were assigned to one of three treatments according to a randomized complete block design. Dietary treatments contained 3 levels of synchrony index (0.39, 0.56 and 0.74 that were derived from laboratory chemical composition analysis and degradation kinetics using nylon bag technique. Diets were fed at the rate of 2.5% BW by separate concentrate and roughage. Average daily gain increased linearly (P<0.05 with increase levels of synchrony index in the diets. The digestibility of dry matter, organic matter and neutral detergent fiber increased linearly (P<0.01. The digestibility of acid detergent fiber increased linearly (P<0.05. Ruminal total volatile fatty acids concentration increased linearly (P<0.05 at 6 h post feeding. Higher concentration and fluctuation of ruminal ammonia nitrogen and blood urea nitrogen were observed in animals that received lower synchrony index in their diets. Rumen microbial population tended to increase with diets having higher levels of synchrony index. The results indicated that synchronized rate of dietary energy and nitrogen degradation improved ruminal fermentation and digestibility, thus this increased the growth rate in Brahman cattle fed with ricestraw- based diets.
Stuebe, Alison M; Jegier, Briana J; Schwarz, Eleanor Bimla; Green, Brittany D; Reinhold, Arnold G; Colaizy, Tarah T; Bogen, Debra L; Schaefer, Andrew J; Jegier, Jamus T; Green, Noah S; Bartick, Melissa C
2017-12-01
We sought to determine the impact of changes in breastfeeding rates on population health. We used a Monte Carlo simulation model to estimate the population-level changes in disease burden associated with marginal changes in rates of any breastfeeding at each month from birth to 12 months of life, and in rates of exclusive breastfeeding from birth to 6 months of life. We used these marginal estimates to construct an interactive online calculator (available at www.usbreastfeeding.org/saving-calc ). The Institutional Review Board of the Cambridge Health Alliance exempted the study. Using our interactive online calculator, we found that a 5% point increase in breastfeeding rates was associated with statistically significant differences in child infectious morbidity for the U.S. population, including otitis media (101,952 cases, 95% confidence interval [CI] 77,929-131,894 cases) and gastrointestinal infection (236,073 cases, 95% CI 190,643-290,278 cases). Associated medical cost differences were $31,784,763 (95% CI $24,295,235-$41,119,548) for otitis media and $12,588,848 ($10,166,203-$15,479,352) for gastrointestinal infection. The state-level impact of attaining Healthy People 2020 goals varied by population size and current breastfeeding rates. Modest increases in breastfeeding rates substantially impact healthcare costs in the first year of life.
Saunier, Olivier; Mathieu, Anne; Didier, Damien; Tombette, Marilyne; Quélo, Denis; Winiarek, Victor; Bocquet, Marc
2013-04-01
The Chernobyl nuclear accident and more recently the Fukushima accident highlighted that the largest source of error on consequences assessment is the source term estimation including the time evolution of the release rate and its distribution between radioisotopes. Inverse modelling methods have proved to be efficient to assess the source term due to accidental situation (Gudiksen, 1989, Krysta and Bocquet, 2007, Stohl et al 2011, Winiarek et al 2012). These methods combine environmental measurements and atmospheric dispersion models. They have been recently applied to the Fukushima accident. Most existing approaches are designed to use air sampling measurements (Winiarek et al, 2012) and some of them use also deposition measurements (Stohl et al, 2012, Winiarek et al, 2013). During the Fukushima accident, such measurements are far less numerous and not as well distributed within Japan than the dose rate measurements. To efficiently document the evolution of the contamination, gamma dose rate measurements were numerous, well distributed within Japan and they offered a high temporal frequency. However, dose rate data are not as easy to use as air sampling measurements and until now they were not used in inverse modelling approach. Indeed, dose rate data results from all the gamma emitters present in the ground and in the atmosphere in the vicinity of the receptor. They do not allow one to determine the isotopic composition or to distinguish the plume contribution from wet deposition. The presented approach proposes a way to use dose rate measurement in inverse modeling approach without the need of a-priori information on emissions. The method proved to be efficient and reliable when applied on the Fukushima accident. The emissions for the 8 main isotopes Xe-133, Cs-134, Cs-136, Cs-137, Ba-137m, I-131, I-132 and Te-132 have been assessed. The Daiichi power plant events (such as ventings, explosions…) known to have caused atmospheric releases are well identified in
Influence of the oil globule fraction on the release rate profiles from multiple W/O/W emulsions.
Bonnet, Marie; Cansell, Maud; Placin, Frédéric; Monteil, Julien; Anton, Marc; Leal-Calderon, Fernando
2010-06-15
Water-in-oil-in-water (W/O/W) double emulsions were prepared and the kinetics of release of magnesium ions from the internal to the external water phase was investigated as a function of the formulation and the globule volume fraction. All the emulsions were formulated using the same surface-active species (polyglycerol polyricinoleate and sodium caseinate). Also, the internal droplet and oil globule diameters were almost identical for all the systems. Two types of W/O/W emulsions were prepared based either on a synthetic oil (miglyol) or on an edible oil (olive oil). The globule volume fraction varied from 11% to 72%. At constant temperature (T=25 degrees C) and irrespective of the oil type, the percentage of magnesium released was lowered by increasing the globule fraction. In all cases, magnesium leakage occurred without film rupturing (no coalescence). Thus, the experimental data were interpreted within the frame of a model based on diffusion. The rate of release was determined by the permeation coefficient of magnesium across the oil phase and by the binding (chelation) of magnesium by caseinate molecules. The data could be adequately fitted by considering a time-dependant permeation coefficient. The better retention of magnesium at high globule fractions could account for two distinct phenomena: (i) the reduction of the relative volume of the outer phase, and (ii) the attenuation of the permeation coefficient over time induced by interfacial magnesium binding, all the more important than the globule fraction increased. Copyright 2010 Elsevier B.V. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Homma, Toshimitsu; Togawa, Orihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1996-11-01
This report provides a tabulation of both external dose-rate conversion factors and internal dose conversion factors using radioactive decay data in the updated Evaluated Nuclear Structure Data File (ENSDF) for selected 26 radionuclides and all their daughter radionuclides of potential importance in safety assessments of fusion facilities. The external dose-rate conversion factors for 21 target organs are tabulated for three exposure modes that are immersion in contaminated air, irradiation at a height of 1 m above a contaminated ground surface and immersion contaminated water. For internal exposure, committed dose equivalents, based on the methodology of ICRP Publication 30, in the same target organs per intake of unit activity are given for the inhalation and ingestion exposure pathways. The data presented here is intended to be generally used for safety assessments of fusion reactors. Comparisons of external effective dose-rate conversion factors and committed effective dose equivalents are made with the previous data from the independent data bases to provide quality assurance on our calculated results. There is generally good agreement among data from the independent data bases. The differences in the values of both effective dose-rate and dose conversion factors appeared are primarily due to differences in calculational methodology, the use of different radioactive decay data, and compilation errors. (author)
International Nuclear Information System (INIS)
Baksi, Soham; Green, Chris
2007-01-01
We specify formulas for computing the rate of decline in economy-wide energy intensity by aggregating its two determinants-technical efficiency improvements in the various sectors of the economy, and shifts in economic activity among these sectors. The formulas incorporate the interdependence between sectoral shares, and establish a one-to-one relation between sectoral output and energy shares. This helps to eliminate future energy intensity decline scenarios which involve implausible values of either sectoral share. An illustrative application of the formulas is provided, using within-sector efficiency improvement estimates suggested by Lightfoot-Green and Harvey
Owlia, P; Vasei, M; Goliaei, B; Nassiri, I
2011-04-01
The interests in journal impact factor (JIF) in scientific communities have grown over the last decades. The JIFs are used to evaluate journals quality and the papers published therein. JIF is a discipline specific measure and the comparison between the JIF dedicated to different disciplines is inadequate, unless a normalization process is performed. In this study, normalized impact factor (NIF) was introduced as a relatively simple method enabling the JIFs to be used when evaluating the quality of journals and research works in different disciplines. The NIF index was established based on the multiplication of JIF by a constant factor. The constants were calculated for all 54 disciplines of biomedical field during 2005, 2006, 2007, 2008 and 2009 years. Also, ranking of 393 journals in different biomedical disciplines according to the NIF and JIF were compared to illustrate how the NIF index can be used for the evaluation of publications in different disciplines. The findings prove that the use of the NIF enhances the equality in assessing the quality of research works produced by researchers who work in different disciplines. Copyright © 2010 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Ling, K.H.; Hanzlik, R.P.
1989-01-01
Liver microsomes from phenobarbital-induced rats oxidize toluene to a mixture of benzyl alcohol plus o-, m- and p-cresol (ca. 69:31). Stepwise deuteration of the methyl group causes stepwise decreases in the yield of benzyl alcohol relative to cresols (ca. 24:76 for toluene-d3). For benzyl alcohol formation from toluene-d3 DV = 1.92 and D(V/K) = 3.53. Surprisingly, however, stepwise deuteration induces stepwise increases in total oxidation, giving rise to an inverse isotope effect overall (DV = 0.67 for toluene-d3). Throughout the series (i.e. d0, d1, d2, d3) the ratios of cresol isomers remain constant. These results are interpreted in terms of product release for benzyl alcohol being slower than release of cresols (or their epoxide precursors), and slow enough to be partially rate-limiting in turnover. Thus metabolic switching to cresol formation causes a net acceleration of turnover
International Nuclear Information System (INIS)
Gibson, J.A.B.
1978-06-01
This report is a brief survey of the methods used for calculating the dose rate from deposited fallout and includes improvements in the computing techniques. The changes consist of (a) the use of a more exact allowance for weathering (b) the calculation doses to mid-month rather than end of each month (c) the inclusion of the contribution from Nb-95 in a more exact way to allow for its build-up and decay with time (d) the use of a more precise method for estimating the dose prior to 1954. The result is to increase the calculated total γ-ray dose from 1951 to 1976 by 17% from 153 to 179 mrad in air at 1 m with an increase of 11% in the beta-ray dose. The annual levels for natural γ and β radiation are 12 and 62 mrad respectively. (author)
International Nuclear Information System (INIS)
Sievers, Juergen; Heckmann, Klaus; Blaesius, Christoph
2015-06-01
For the demonstration of break preclusion for pressure retaining components in nuclear power plants, the nuclear safety standard KTA 3206 determines also the requirements for the leak-before-break verification. For this procedure, it has to be ensured that a wall-penetrating crack is subcritical with respect to instable growth, and that the resulting leakage under stationary operation conditions can be detected by a leak detection system. Within the scope of the project 3613R01332 analyses with respect to conservative estimates of the leak rates in case of detections regarding break preclusion were performed by means of leak rate models being available at GRS. For this purpose, conservative assumptions in the procedure were quantified by comparative calculations concerning selected leak rate experiments and the requirements regarding the determination of leak rates indicated in the KTA 3206 were verified and specified. Moreover, the models were extended and relevant recommendations for the calculation procedure were developed. During the investigations of leak rate tests the calculation methods were validated, qualified by means of both examples indicated in KTA 3206 and applied to a postulated leak accident in the cooling circuit of a PWR. For the calculation of leak rates several simplified solution methods which are included in the GRS program WinLeck were applied, and for the simulation of a leak accident the large-scale programs ANSYS Mechanical and ATHLET (thermohydraulics program developed by GRS) were used. When applying simplified methods for the calculation of leak rates using the limiting curve for the friction factor which has been derived during the project and which is included in the KTA 3206 attention has to be paid to the fact that in case of small flow lengths the entrance loss can dominate compared to the friction loss. However, the available data do not suffice in order to make a quantitative statement with respect to limits of applicability
Brugger, Markus; Assmann, R W; Forkel-Wirth, Doris; Menzel, Hans Gregor; Roesler, Stefan; Vincke, Helmut H
2005-01-01
Radiation protection of the personnel who will perform interventions in the LHC Beam Cleaning Insertions is mandatory and includes the design of equipment and the establishment of work procedures. Residual dose rates due to activated equipment are expected to reach significant values such that any maintenance has to be planned and optimized in advance. Three-dimensional maps of dose equivalent rates at different cooling times after operation of the LHC have been calculated with FLUKA. The simulations are based on an explicit calculation of induced radioactivity and of the transport of the radiation from the radioactive decay. The paper summarizes the results for the Beam Cleaning Insertions and discusses the estimation of individual and collective doses received by personnel during critical interventions, such as the exchange of a collimator or the installation of Phase 2. The given examples outline the potential and the need to optimize, in an iterative way, the design of components as well as the layout of ...
Directory of Open Access Journals (Sweden)
Stephen Carstens
2008-11-01
Full Text Available Companies tend to outsource transport to fleet management companies to increase efficiencies if transport is a non-core activity. The provision of fleet management services on contract introduces a certain amount of financial risk to the fleet management company, specifically fixed rate maintenance contracts. The quoted rate needs to be sufficient and also competitive in the market. Currently the quoted maintenance rates are based on the maintenance specifications of the manufacturer and the risk management approach of the fleet management company. This is usually reflected in a contingency that is included in the quoted maintenance rate. An alternative methodology for calculating the average maintenance cost for a vehicle fleet is proposed based on the actual maintenance expenditures of the vehicles and accepted statistical techniques. The proposed methodology results in accurate estimates (and associated confidence limits of the true average maintenance cost and can beused as a basis for the maintenance quote.
Semiclassical calculation of ionisation rate for Rydberg helium atoms in an electric field
International Nuclear Information System (INIS)
Wang De-Hua
2011-01-01
The ionisation of Rydberg helium atoms in an electric field above the classical ionisation threshold has been examined using the semiclassical method, with particular emphasis on discussing the influence of the core scattering on the escape dynamics of electrons. The results show that the Rydberg helium atoms ionise by emitting a train of electron pulses. Unlike the case of the ionisation of Rydberg hydrogen atom in parallel electric and magnetic fields, where the pulses of the electron are caused by the external magnetic field, the pulse trains for Rydberg helium atoms are created through core scattering. Each peak in the ionisation rate corresponds to the contribution of one core-scattered combination trajectory. This fact further illustrates that the ionic core scattering leads to the chaotic property of the Rydberg helium atom in external fields. Our studies provide a simple explanation for the escape dynamics in the ionisation of nonhydrogenic atoms in external fields. (atomic and molecular physics)
On the symmetric α-stable distribution with application to symbol error rate calculations
Soury, Hamza
2016-12-24
The probability density function (PDF) of the symmetric α-stable distribution is investigated using the inverse Fourier transform of its characteristic function. For general values of the stable parameter α, it is shown that the PDF and the cumulative distribution function of the symmetric stable distribution can be expressed in terms of the Fox H function as closed-form. As an application, the probability of error of single input single output communication systems using different modulation schemes with an α-stable perturbation is studied. In more details, a generic formula is derived for generalized fading distribution, such as the extended generalized-k distribution. Later, simpler expressions of these error rates are deduced for some selected special cases and compact approximations are derived using asymptotic expansions.
First Lattice Calculation of the QED Corrections to Leptonic Decay Rates
Giusti, D.; Lubicz, V.; Tarantino, C.; Martinelli, G.; Sachrajda, C. T.; Sanfilippo, F.; Simula, S.; Tantalo, N.
2018-02-01
The leading-order electromagnetic and strong isospin-breaking corrections to the ratio of Kμ 2 and πμ 2 decay rates are evaluated for the first time on the lattice, following a method recently proposed. The lattice results are obtained using the gauge ensembles produced by the European Twisted Mass Collaboration with Nf=2 +1 +1 dynamical quarks. Systematic effects are evaluated and the impact of the quenched QED approximation is estimated. Our result for the correction to the tree-level Kμ 2/πμ 2 decay ratio is -1.22 (16 )%, to be compared to the estimate of -1.12 (21 )% based on chiral perturbation theory and adopted by the Particle Data Group.
International Nuclear Information System (INIS)
Lee, Gyeong Geun; Lee, Yong Bok; Kim, Min Chul; Kwon, Junh Yun
2012-01-01
Neutron irradiation to reactor pressure vessel (RPV) steels causes a decrease in fracture toughness and an increase in yield strength while in service. It is generally accepted that the growth of point defect cluster (PDC) and copper rich precipitate (CRP) affects radiation hardening of RPV steels. A number of models have been proposed to account for the embrittlement of RPV steels. The rate theory based modeling mathematically described the evolution of radiation induced microstructures of ferritic steels under neutron irradiation. In this work, we compared the rate theory based modeling calculation with the surveillance test results of Korean Light Water Reactors (LWRs)
International Nuclear Information System (INIS)
Stiller, W.
1985-01-01
A classical collision theory is used to describe thermal bimolecular rate coefficeints for reaction between positive and negative ions and polar molecules in a carrier gas. Special attention is paid to ion-molecule reaction in which proton transfer occurs. These reactions play an important role in terrestrial plasma devices, in ionosphere, in planetary atmospheres and in interstellar matter. The equilibrium rate coefficients of the reactions are calculated based on a microscopic reactive cross section derived from a long distance polar molecule-ion potential. The results are compared with experimental values of afterglow measurements. (D.Gy.)
International Nuclear Information System (INIS)
Jarvis, O.N.; Sadler, G.; Avery, A.; Verschuur, K.A.
1988-01-01
The gamma-radiation dose-rates inside the JET vacuum vessel due to induced radioactivity were measured at intervals throughout the 1986 period of operation, and the decay gamma energy spectrum was measured during the subsequent lengthy shutdown. The dose-rates were found to be in good agreement with values calculated using the neutron yield records compiled from the time-resolved neutron yield monitor responses for individual discharges. This result provides strong support for the reliability of the neutron yield monitor calibration. (author)
Kumar, Pankaj; Mohan, Chander; KanamSrinivasan Uma Shankar, Mara; Gulati, Monica
2011-01-01
In the present study solid dispersions of the antifungal drug Ketoconazole were prepared with Pluronic F-127 and PVP K-30 with an intention to improve its dissolution properties. Investigations of the properties of the dispersions were performed using release studies, Differential scanning calorimetery (DSC), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). The results obtained showed that the rate of dissolution of Ketoconazole was considerably improved when formulated in solid dispersions with PVP K-30 and Pluronic F-127 as compared with pure drug and physical mixtures. The results from DSC and XRD studies showed the transition of crystalline nature of drug to amorphous form, while FTIR studies demonstrated the absence of drug-carriers interaction. PMID:24250403
International Nuclear Information System (INIS)
Medley, S.S.; Darrow, D.S.; Roquemore, A.L.
2005-01-01
A change in the response of the neutron detectors on the National Spherical Torus Experiment occurred between the 2002-2003 and 2004 experimental run periods. An analysis of this behavior by investigating the neutron diagnostic operating conditions and comparing measured and TRANSP-calculated neutron rates is presented. Also a revised procedure for cross calibration of the neutron scintillator detectors with the fission chamber detectors was implemented that delivers good agreement amongst the measured neutron rates for all neutron detectors and all run periods. For L-mode discharges, the measured and TRANSP-calculated neutron rates now match closely for all run years. For H-mode discharges over the entire 2002-2004 period, the 2FG scintillator and fission chamber measurements match each other but imply a neutron deficit of 11.5% relative to the TRANSP-calculated neutron. The results of this report impose a modification on all of the previously used calibration factors for the entire neutron detector suite over the 2002-2004 period. A tabular summary of the new calibration factors is provided including certified calibration factors for the 2005 run
Wang, K.; Chen, Z. B.; Chen, C. Y.; Yan, J.; Dang, W.; Zhao, X. H.; Yang, X.
2017-09-01
Multi-configuration Dirac-Fock (MCDF) calculations of energy levels, wavelengths, oscillator strengths, lifetimes, and electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), magnetic quadrupole (M2) transition rates are reported for the arsenic isoelectronic sequence Sn XVIII-Ba XXIV, W XLII. Results are presented among the 86 levels of the 4s2 4p3, 4 s 4p4, 4p5, 4s2 4p2 4 d, and 4 s 4p3 4 d configurations in each ion. The relativistic atomic structure package GRASP2K is adopted for the calculations, in which the contributions from the correlations within the n ≤ 7 complexes, Breit interaction (BI) and quantum electrodynamics (QED) effects are taking into account. The many-body perturbation theory (MBPT) method is also employed as an independent calculation for comparison purposes, taking W XLII as an example. Calculated results are compared with data from other calculations and the observed values from the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST). Good agreements are obtained. i.e, the accuracy of our energy levels is assessed to be better than 0.6%. These accurate theoretical data should be useful for diagnostics of hot plasmas in fusion devices.
Weather Correlations to Calculate Infiltration Rates for U. S. Commercial Building Energy Models.
Ng, Lisa C; Quiles, Nelson Ojeda; Dols, W Stuart; Emmerich, Steven J
2018-01-01
As building envelope performance improves, a greater percentage of building energy loss will occur through envelope leakage. Although the energy impacts of infiltration on building energy use can be significant, current energy simulation software have limited ability to accurately account for envelope infiltration and the impacts of improved airtightness. This paper extends previous work by the National Institute of Standards and Technology that developed a set of EnergyPlus inputs for modeling infiltration in several commercial reference buildings using Chicago weather. The current work includes cities in seven additional climate zones and uses the updated versions of the prototype commercial building types developed by the Pacific Northwest National Laboratory for the U. S. Department of Energy. Comparisons were made between the predicted infiltration rates using three representations of the commercial building types: PNNL EnergyPlus models, CONTAM models, and EnergyPlus models using the infiltration inputs developed in this paper. The newly developed infiltration inputs in EnergyPlus yielded average annual increases of 3 % and 8 % in the HVAC electrical and gas use, respectively, over the original infiltration inputs in the PNNL EnergyPlus models. When analyzing the benefits of building envelope airtightening, greater HVAC energy savings were predicted using the newly developed infiltration inputs in EnergyPlus compared with using the original infiltration inputs. These results indicate that the effects of infiltration on HVAC energy use can be significant and that infiltration can and should be better accounted for in whole-building energy models.
International Nuclear Information System (INIS)
Piepsz, Amy; Tondeur, Marianne; Ham, Hamphrey
2008-01-01
51 Cr ethylene diamine tetraacetic acid ( 51 Cr EDTA) clearance is nowadays considered as an accurate and reproducible method for measuring glomerular filtration rate (GFR) in children. Normal values in function of age, corrected for body surface area, have been recently updated. However, much criticism has been expressed about the validity of body surface area correction. The aim of the present paper was to present the normal GFR values, not corrected for body surface area, with the associated percentile curves. For that purpose, the same patients as in the previous paper were selected, namely those with no recent urinary tract infection, having a normal left to right 99m Tc MAG3 uptake ratio and a normal kidney morphology on the early parenchymal images. A single blood sample method was used for 51 Cr EDTA clearance measurement. Clearance values, not corrected for body surface area, increased progressively up to the adolescence. The percentile curves were determined and allow, for a single patient, to estimate accurately the level of non-corrected clearance and the evolution with time, whatever the age. (orig.)
Zhang, Hongzhi R; Huynh, Lam K; Kungwan, Nawee; Yang, Zhiwei; Zhang, Shaowen
2007-05-17
The Utah Surrogate Mechanism was extended in order to model a stoichiometric premixed cyclohexane flame (P = 30 Torr). Generic rates were assigned to reaction classes of hydrogen abstraction, beta scission, and isomerization, and the resulting mechanism was found to be adequate in describing the combustion chemistry of cyclohexane. Satisfactory results were obtained in comparison with the experimental data of oxygen, major products and important intermediates, which include major soot precursors of C2-C5 unsaturated species. Measured concentrations of immediate products of fuel decomposition were also successfully reproduced. For example, the maximum concentrations of benzene and 1,3-butadiene, two major fuel decomposition products via competing pathways, were predicted within 10% of the measured values. Ring-opening reactions compete with those of cascading dehydrogenation for the decomposition of the conjugate cyclohexyl radical. The major ring-opening pathways produce 1-buten-4-yl radical, molecular ethylene, and 1,3-butadiene. The butadiene species is formed via beta scission after a 1-4 internal hydrogen migration of 1-hexen-6-yl radical. Cascading dehydrogenation also makes an important contribution to the fuel decomposition and provides the exclusive formation pathway of benzene. Benzene formation routes via combination of C2-C4 hydrocarbon fragments were found to be insignificant under current flame conditions, inferred by the later concentration peak of fulvene, in comparison with benzene, because the analogous species series for benzene formation via dehydrogenation was found to be precursors with regard to parent species of fulvene.
Energy Technology Data Exchange (ETDEWEB)
Piepsz, Amy; Tondeur, Marianne [CHU St. Pierre, Department of Radioisotopes, Brussels (Belgium); Ham, Hamphrey [University Hospital Ghent, Department of Nuclear Medicine, Ghent (Belgium)
2008-09-15
{sup 51}Cr ethylene diamine tetraacetic acid ({sup 51}Cr EDTA) clearance is nowadays considered as an accurate and reproducible method for measuring glomerular filtration rate (GFR) in children. Normal values in function of age, corrected for body surface area, have been recently updated. However, much criticism has been expressed about the validity of body surface area correction. The aim of the present paper was to present the normal GFR values, not corrected for body surface area, with the associated percentile curves. For that purpose, the same patients as in the previous paper were selected, namely those with no recent urinary tract infection, having a normal left to right {sup 99m}Tc MAG3 uptake ratio and a normal kidney morphology on the early parenchymal images. A single blood sample method was used for {sup 51}Cr EDTA clearance measurement. Clearance values, not corrected for body surface area, increased progressively up to the adolescence. The percentile curves were determined and allow, for a single patient, to estimate accurately the level of non-corrected clearance and the evolution with time, whatever the age. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Benslimane-Bouland, A
1997-09-01
The framework of this study was the evaluation of the nuclear data requirements for Actinides and Fission Products applied to current nuclear reactors as well as future applications. This last item includes extended irradiation campaigns, 100 % Mixed Oxide fuel, transmutation or even incineration. The first part of this study presents different types of integral measurements which are available for capture rate measurements, as well as the methods used for reactor core calculation route design and nuclear data library validation. The second section concerns the analysis of three specific irradiation experiments. The results have shown the extent of the current knowledge on nuclear data as well as the associated uncertainties. The third and last section shows both the coherency between all the results, and the statistical method applied for nuclear data library adjustment. A relevant application of this method has demonstrated that only specifically chosen integral experiments can be of use for the validation of nuclear data libraries. The conclusion is reached that even if co-ordinated efforts between reactor and nuclear physicists have made possible a huge improvement in the knowledge of capture cross sections of the main nuclei such as uranium and plutonium, some improvements are currently necessary for the minor actinides (Np, Am and Cm). Both integral and differential measurements are recommended to improve the knowledge of minor actinide cross sections. As far as integral experiments are concerned, a set of criteria to be followed during the experimental conception have been defined in order to both reduce the number of required calculation approximations, and to increase as much as possible the maximum amount of extracted information. (author)
Markenscoff, Xanthippi; Ni, Luqun
2010-01-01
In the context of the linear theory of elasticity with eigenstrains, the radiated field including inertia effects of a spherical inclusion with dilatational eigenstrain radially expanding is obtained on the basis of the dynamic Green's function, and one of the half-space inclusion boundary (with dilatational eigenstrain) moving from rest in general subsonic motion is obtained by a limiting process from the spherically expanding inclusion as the radius tends to infinity while the eigenstrain remains constrained, and this is the minimum energy solution. The global energy-release rate required to move the plane inclusion boundary and to create an incremental region of eigenstrain is defined analogously to the one for moving cracks and dislocations and represents the mechanical rate of work needed to be provide for the expansion of the inclusion. The calculated value, which is the "self-force" of the expanding inclusion, has a static component plus a dynamic one depending only on the current value of the velocity, while in the case of the spherical boundary, there is an additional contribution accounting for the jump in the strain at the farthest part at the back of the inclusion having the time to reach the front boundary, thus making the dynamic "self-force" history dependent.
Energy Technology Data Exchange (ETDEWEB)
Petrizzi, L.; Batistoni, P.; Migliori, S. [Associazione EURATOM ENEA sulla Fusione, Frascati (Roma) (Italy); Chen, Y.; Fischer, U.; Pereslavtsev, P. [Association FZK-EURATOM Forschungszentrum Karlsruhe (Germany); Loughlin, M. [EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire, OX (United Kingdom); Secco, A. [Nice Srl Via Serra 33 Camerano Casasco AT (Italy)
2003-07-01
In deuterium-deuterium (D-D) and deuterium-tritium (D-T) fusion plasmas neutrons are produced causing activation of JET machine components. For safe operation and maintenance it is important to be able to predict the induced activation and the resulting shut down dose rates. This requires a suitable system of codes which is capable of simulating both the neutron induced material activation during operation and the decay gamma radiation transport after shut-down in the proper 3-D geometry. Two methodologies to calculate the dose rate in fusion devices have been developed recently and applied to fusion machines, both using the MCNP Monte Carlo code. FZK has developed a more classical approach, the rigorous 2-step (R2S) system in which MCNP is coupled to the FISPACT inventory code with an automated routing. ENEA, in collaboration with the ITER Team, has developed an alternative approach, the direct 1 step method (D1S). Neutron and decay gamma transport are handled in one single MCNP run, using an ad hoc cross section library. The intention was to tightly couple the neutron induced production of a radio-isotope and the emission of its decay gammas for an accurate spatial distribution and a reliable calculated statistical error. The two methods have been used by the two Associations to calculate the dose rate in five positions of JET machine, two inside the vacuum chamber and three outside, at cooling times between 1 second and 1 year after shutdown. The same MCNP model and irradiation conditions have been assumed. The exercise has been proposed and financed in the frame of the Fusion Technological Program of the JET machine. The scope is to supply the designers with the most reliable tool and data to calculate the dose rate on fusion machines. Results showed that there is a good agreement: the differences range between 5-35%. The next step to be considered in 2003 will be an exercise in which the comparison will be done with dose-rate data from JET taken during and
International Nuclear Information System (INIS)
Petrizzi, L.; Batistoni, P.; Migliori, S.; Chen, Y.; Fischer, U.; Pereslavtsev, P.; Loughlin, M.; Secco, A.
2003-01-01
In deuterium-deuterium (D-D) and deuterium-tritium (D-T) fusion plasmas neutrons are produced causing activation of JET machine components. For safe operation and maintenance it is important to be able to predict the induced activation and the resulting shut down dose rates. This requires a suitable system of codes which is capable of simulating both the neutron induced material activation during operation and the decay gamma radiation transport after shut-down in the proper 3-D geometry. Two methodologies to calculate the dose rate in fusion devices have been developed recently and applied to fusion machines, both using the MCNP Monte Carlo code. FZK has developed a more classical approach, the rigorous 2-step (R2S) system in which MCNP is coupled to the FISPACT inventory code with an automated routing. ENEA, in collaboration with the ITER Team, has developed an alternative approach, the direct 1 step method (D1S). Neutron and decay gamma transport are handled in one single MCNP run, using an ad hoc cross section library. The intention was to tightly couple the neutron induced production of a radio-isotope and the emission of its decay gammas for an accurate spatial distribution and a reliable calculated statistical error. The two methods have been used by the two Associations to calculate the dose rate in five positions of JET machine, two inside the vacuum chamber and three outside, at cooling times between 1 second and 1 year after shutdown. The same MCNP model and irradiation conditions have been assumed. The exercise has been proposed and financed in the frame of the Fusion Technological Program of the JET machine. The scope is to supply the designers with the most reliable tool and data to calculate the dose rate on fusion machines. Results showed that there is a good agreement: the differences range between 5-35%. The next step to be considered in 2003 will be an exercise in which the comparison will be done with dose-rate data from JET taken during and
Directory of Open Access Journals (Sweden)
Witkowski Kazimierz
2017-01-01
Full Text Available The paper analyzes the possibility to use the electronic type indicators in the diagnosis of marine engines. It has been shown that in-depth analysis of indicator diagrams would be useful – calculation of heat release characteristics. To make this possible, measuring indicated systems should meet a number of important requirements in or-der to ensure that they can be used for the diagnostic purposes. These includes: high precision sensors for the measurement of cylinder pressure, high speed and accuracy of measuring and recording of measured values. These also includes reliable determination of the top dead center piston (TDC. In order to demonstrate the impact of positional error TDC, simulation study was conducted in which indicated diagrams were used, obtained on a medium-speed four-stroke marine diesel engine type A25/30 and the low-speed two-stroke marine diesel engine type RTA76, Sulzer company.
International Nuclear Information System (INIS)
Sweeton, F.H.
1975-09-01
The CUEX (Cumulative Exposure Index) relates the concentrations of various nuclides in the environment to assigned annual dose limits. A computer code has been written to calculate this index for stack releases of radioactivity. This report is written to illustrate how the code in its present form can be applied to a particular reactor. The data used here are from the Haddam Neck (Connecticut Yankee) Nuclear Power Plant, a relatively large plant that has been in operation for 6 years. The results show that the highest exposure expected from the actual releases of gaseous 85 Kr, 133 Xe, 131 I, and 3 H is about 0.2 percent of the as low as practicable limits set by the Nuclear Regulatory Commission. Of the nuclides considered, 133 Xe is by far the most important; the chief mode of exposure to this nuclide is submersion in air. In the case of 131 I the main exposure route is external irradiation from the activity on the ground except for the special case of the thyroid for which about 70 per []ent of the exposure arises from ingestion. (auth)
International Nuclear Information System (INIS)
Fan, Chuan Gang; Li, Ying Zhen; Ingason, Haukur; Lönnermark, Anders
2016-01-01
Highlights: • The effect of tunnel cross section together with ventilation velocity was studied. • Ceiling temperature varies clearly with tunnel height, but little with tunnel width. • Downstream temperature decreases with increasing tunnel dimensions. • HRR is an important factor that influences decay rate of excess gas temperature. • An equation considering both tunnel dimensions and HRR was developed. - Abstract: Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.
Shephard, R W; Morton, J M; Norman, S T
2014-01-10
A controlled trial investigating the effect on conception of administration of 250 μg of gonadotropin-releasing hormone (GnRH) at artificial insemination (AI) in dairy cows in seasonal or split calving herds was conducted. Time of detection of estrus, body condition, extent of estrous expression, treatment, breed, age and milk production from the most recent herd test of the current lactation was recorded. Cows were tested for pregnancy with fetal aging between 35 and 135 days after AI. Sixteen herds provided 2344 spring-calved cows and 3007 inseminations. Logistic regression adjusting for clustering at herd level was used to examine the effect of treatment for first (2344) and second (579) inseminations separately. For first AI, treatment significantly improved conception rate in cows with milk protein concentrations of 3.75% or greater and for cows with milk protein concentrations between 3.00% and 3.50% and less than 40 days calved; increased conception rate from 41.2% to 53.4%. Treatment reduced conception rates in cows with milk protein concentrations of 2.75% or less. Treating only cows identified as responding positively to treatment (11% of all study cows) was estimated to increase first service conception rate in herds from 48.1% to 49.4%. There was no significant effect of treatment on conception to second AI, nor any significant interactions. These findings indicate that GnRH at AI should be limited to the sub-group cows most likely to respond. The positive effect of GnRH at AI may be mediated through improved oocyte maturation and/or improved luteal function, rather than by reducing AI-to-ovulation intervals. Copyright © 2013 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Salminen, E.K.; Salminen, S.J.; Porkka, L.; Kwasowski, P.; Marks, V.; Koivistoinen, P.E.
1989-01-01
The effect of xylitol and glucose on the rate of gastric emptying and intestinal transit and on motilin, gastric inhibitory polypeptide (GIP), and insulin release were studied in human volunteers. A single oral dose of 200 mL water containing 30 g glucose or 30 g xylitol, mixed with a 99m technetium-tin (99mTc-Sn) colloid, was used. Similar dosing without the label was used in motilin, GIP, and insulin studies. Xylitol decreased the rate of gastric emptying but concomitantly accelerated intestinal transit compared with glucose. The half-times for gastric emptying were 77.5 +/- 4.6 and 39.8 +/- 3.4 min after ingestion of xylitol and glucose solutions, respectively. Glucose suppressed motilin and stimulated GIP secretion; xylitol stimulated motilin secretion but had no effect on GIP, which is currently the main candidate for the role of enterogastrone. The accelerated intestinal transit and increase in plasma motilin observed after xylitol ingestion were thought to be causally related to the diarrhea and gastrointestinal discomfort produced by it
Vilariño, M; Rubianes, E; Menchaca, A
2013-01-01
The objective was to determine serum progesterone concentrations, ovarian responses, and pregnancy rate in sheep inseminated following a short-term protocol (6 days of treatment) with a previously used controlled internal drug release-G (CIDR-G) device. In experiment 1, 30 ewes were put on a short-term protocol using a CIDR-G of first use (new devices, N = 10), second use (previously used for 6 days, N = 10), or third use (previously used twice for 6 days, N = 10). All ewes were given prostaglandin F(2α) (10 mg dinoprost) and eCG (300 IU) im at device withdrawal. Mean serum progesterone concentrations were greater for ewes treated with new versus reused devices (P synchronization and ovulation, with lower serum progesterone concentrations for reused devices. Three times used CIDR-G yielded a pregnancy rate >70%, which tended to be lower than that obtained with new devices, adding evidence of the detrimental effect of low serum progesterone concentrations on fertility in sheep. Copyright © 2013 Elsevier Inc. All rights reserved.
Valiev, R R; Cherepanov, V N; Baryshnikov, G V; Sundholm, D
2018-02-28
A method for calculating the rate constants for internal-conversion (k IC ) and intersystem-crossing (k ISC ) processes within the adiabatic and Franck-Condon (FC) approximations is proposed. The applicability of the method is demonstrated by calculation of k IC and k ISC for a set of organic and organometallic compounds with experimentally known spectroscopic properties. The studied molecules were pyrromethene-567 dye, psoralene, hetero[8]circulenes, free-base porphyrin, naphthalene, and larger polyacenes. We also studied fac-Alq 3 and fac-Ir(ppy) 3 , which are important molecules in organic light emitting diodes (OLEDs). The excitation energies were calculated at the multi-configuration quasi-degenerate second-order perturbation theory (XMC-QDPT2) level, which is found to yield excitation energies in good agreement with experimental data. Spin-orbit coupling matrix elements, non-adiabatic coupling matrix elements, Huang-Rhys factors, and vibrational energies were calculated at the time-dependent density functional theory (TDDFT) and complete active space self-consistent field (CASSCF) levels. The computed fluorescence quantum yields for the pyrromethene-567 dye, psoralene, hetero[8]circulenes, fac-Alq 3 and fac-Ir(ppy) 3 agree well with experimental data, whereas for the free-base porphyrin, naphthalene, and the polyacenes, the obtained quantum yields significantly differ from the experimental values, because the FC and adiabatic approximations are not accurate for these molecules.
Soong, David T.; Murphy, Elizabeth A.; Straub, Timothy D.
2009-01-01
The effects of stormwater detention basins with specified release rates are examined on the watershed scale with a Hydrological Simulation Program - FORTRAN (HSPF) continuous-simulation model. Modeling procedures for specifying release rates from detention basins with orifice and weir discharge configurations are discussed in this report. To facilitate future detention modeling as a tool for watershed management, a chart relating watershed impervious area to detention volume is presented. The report also presents a case study of the Blackberry Creek watershed in Kane County, Ill., a rapidly urbanizing area seeking to avoid future flood damages from increased urbanization, to illustrate the effects of various detention basin release rates on flood peaks and volumes and flood frequencies. The case study compares flows simulated with a 1996 land-use HSPF model to those simulated with four different 2020 projected land-use HSPF model scenarios - no detention, and detention basins with release rates of 0.08, 0.10, and 0.12 cubic feet per second per acre (ft3/s-acre), respectively. Results of the simulations for 15 locations, which included the downstream ends of all tributaries and various locations along the main stem, showed that a release rate of 0.10 ft3/s-acre, in general, can maintain postdevelopment 100-year peak-flood discharge at a similar magnitude to that of 1996 land-use conditions. Although the release rate is designed to reduce the 100-year peak flow, reduction of the 2-year peak flow is also achieved for a smaller proportion of the peak. Results also showed that the 0.10 ft3/s-acre release rate was less effective in watersheds with relatively high percentages of preexisting (1996) development than in watersheds with less preexisting development.
Homayoon, Zahra; Jambrina, Pablo G.; Aoiz, F. Javier; Bowman, Joel M.
2012-07-01
In a previous paper [P. G. Jambrina et al., J. Chem. Phys. 135, 034310 (2011), 10.1063/1.3611400] various calculations of the rate coefficient for the Mu + H2 → MuH + H reaction were presented and compared to experiment. The widely used standard quasiclassical trajectory (QCT) method was shown to overestimate the rate coefficients by several orders of magnitude over the temperature range 200-1000 K. This was attributed to a major failure of that method to describe the correct threshold for the reaction owing to the large difference in zero-point energies (ZPE) of the reactant H2 and product MuH (˜0.32 eV). In this Communication we show that by performing standard QCT calculations for the reverse reaction and then applying detailed balance, the resulting rate coefficient is in very good agreement with the other computational results that respect the ZPE, (as well as with the experiment) but which are more demanding computationally.
International Nuclear Information System (INIS)
Shinn, J.H.; Homan, D.N.
1982-01-01
This study determined the plutonium-aerosol fluxes from the soil to quantify (1) the extent of potential human exposure by deep-lung retention of alpha-emitting particles; (2) the source term should there be any significant, long-term, transport of plutonium aerosols; and (3) the resuspension factor and rate so that, for the first time at any nuclear site, one may calculate how long it will take for wind erosion to carry away a significant amount of the contaminated soil. High-volume air samplers and cascade impactors were used to characterize the plutonium aerosols. Meteorological flux-profile methods were used to calculate dust and plutonium aerosol emission rates. A floorless wind tunnel (10-m long) was used to examine resuspension under steady-state, high wind speed. The resuspension factor was two orders of magnitude lower than the other comparable sites at NTS and elsewhere, and the average resuspension rate of 5.3 x 10 -8 /d was also very low, so that the half-time for resuspension by wind erosion was about 36,000 y
Energy Technology Data Exchange (ETDEWEB)
Rusin, Tiago; Rebello, Wilson F.; Vellozo, Sergio O.; Gomes, Renato G., E-mail: tiagorusin@ime.eb.b, E-mail: rebello@ime.eb.b, E-mail: vellozo@cbpf.b, E-mail: renatoguedes@ime.eb.b [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Nuclear; Vital, Helio C., E-mail: vital@ctex.eb.b [Centro Tecnologico do Exercito (CTEx), Rio de Janeiro, RJ (Brazil); Silva, Ademir X., E-mail: ademir@con.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear
2011-07-01
A cavity-type cesium-137 research irradiating facility at CTEx has been modeled by using the Monte Carlo code MCNPX. The irradiator has been daily used in experiments to optimize the use of ionizing radiation for conservation of many kinds of food and to improve materials properties. In order to correlate the effects of the treatment, average doses have been calculated for each irradiated sample, accounting for the measured dose rate distribution in the irradiating chambers. However that approach is only approximate, being subject to significant systematic errors due to the heterogeneous internal structure of most samples that can lead to large anisotropy in attenuation and Compton scattering properties across the media. Thus this work is aimed at further investigating such uncertainties by calculating the dose rate distribution inside the items treated such that a more accurate and representative estimate of the total absorbed dose can be determined for later use in the effects-versus-dose correlation curves. Samples of different simplified geometries and densities (spheres, cylinders, and parallelepipeds), have been modeled to evaluate internal dose rate distributions within the volume of the samples and the overall effect on the average dose. (author)