Pennsylvania Source Term Tracking System

International Nuclear Information System (INIS)

1992-08-01

The Pennsylvania Source Term Tracking System tabulates surveys received from radioactive waste generators in the Commonwealth of radioactive waste is collected each quarter from generators using the Low-Level Radioactive Waste Management Quarterly Report Form (hereafter called the survey) and then entered into the tracking system data base. This personal computer-based tracking system can generate 12 types of tracking reports. The first four sections of this reference manual supply complete instructions for installing and setting up the tracking system on a PC. Section 5 presents instructions for entering quarterly survey data, and Section 6 discusses generating reports. The appendix includes samples of each report

SOURCE TERMS FOR HLW GLASS CANISTERS

International Nuclear Information System (INIS)

J.S. Tang

2000-01-01

This calculation is prepared by the Monitored Geologic Repository (MGR) Waste Package Design Section. The objective of this calculation is to determine the source terms that include radionuclide inventory, decay heat, and radiation sources due to gamma rays and neutrons for the high-level radioactive waste (HLW) from the, West Valley Demonstration Project (WVDP), Savannah River Site (SRS), Hanford Site (HS), and Idaho National Engineering and Environmental Laboratory (INEEL). This calculation also determines the source terms of the canister containing the SRS HLW glass and immobilized plutonium. The scope of this calculation is limited to source terms for a time period out to one million years. The results of this calculation may be used to carry out performance assessment of the potential repository and to evaluate radiation environments surrounding the waste packages (WPs). This calculation was performed in accordance with the Development Plan ''Source Terms for HLW Glass Canisters'' (Ref. 7.24)

10 CFR 50.67 - Accident source term.

Science.gov (United States)

2010-01-01

... Conditions of Licenses and Construction Permits § 50.67 Accident source term. (a) Applicability. The... 10 Energy 1 2010-01-01 2010-01-01 false Accident source term. 50.67 Section 50.67 Energy NUCLEAR... to January 10, 1997, who seek to revise the current accident source term used in their design basis...

Source term estimation during incident response to severe nuclear power plant accidents

International Nuclear Information System (INIS)

McKenna, T.J.; Glitter, J.G.

1988-10-01

This document presents a method of source term estimation that reflects the current understanding of source term behavior and that can be used during an event. The various methods of estimating radionuclide release to the environment (source terms) as a result of an accident at a nuclear power reactor are discussed. The major factors affecting potential radionuclide releases off site (source terms) as a result of nuclear power plant accidents are described. The quantification of these factors based on plant instrumentation also is discussed. A range of accident conditions from those within the design basis to the most severe accidents possible are included in the text. A method of gross estimation of accident source terms and their consequences off site is presented. 39 refs., 48 figs., 19 tabs

Relation between source term and emergency planning for nuclear power plants

International Nuclear Information System (INIS)

Shi Zhongqi; Yang Ling

1992-01-01

Some background information of the severe accidents and source terms related to the nuclear power plant emergency planning are presented. The new source term information in NUREG-0956 and NUREG-1150, and possible changes in emergency planning requirements in U.S.A. are briefly provided. It is suggested that a principle is used in selecting source terms for establishing the emergency planning policy and a method is used in determining the Emergency Planning Zone (EPZ) size in China. Based on the research results of (1) EPZ size of PWR nuclear power plants being built in China, and (2) impact of reactor size and selected source terms on the EPZ size, it is concluded that the suggested principle and the method are suitable and feasible for PWR nuclear power plants in China

Accident source terms for Light-Water Nuclear Power Plants. Final report

International Nuclear Information System (INIS)

Soffer, L.; Burson, S.B.; Ferrell, C.M.; Lee, R.Y.; Ridgely, J.N.

1995-02-01

In 1962 tile US Atomic Energy Commission published TID-14844, ''Calculation of Distance Factors for Power and Test Reactors'' which specified a release of fission products from the core to the reactor containment for a postulated accident involving ''substantial meltdown of the core''. This ''source term'', tile basis for tile NRC's Regulatory Guides 1.3 and 1.4, has been used to determine compliance with tile NRC's reactor site criteria, 10 CFR Part 100, and to evaluate other important plant performance requirements. During the past 30 years substantial additional information on fission product releases has been developed based on significant severe accident research. This document utilizes this research by providing more realistic estimates of the ''source term'' release into containment, in terms of timing, nuclide types, quantities and chemical form, given a severe core-melt accident. This revised ''source term'' is to be applied to the design of future light water reactors (LWRs). Current LWR licensees may voluntarily propose applications based upon it

Source terms in relation to air cleaning

International Nuclear Information System (INIS)

Bernero, R.M.

1985-01-01

There are two sets of source terms for consideration in air cleaning, those for routine releases and those for accident releases. With about 1000 reactor years of commercial operating experience in the US done, there is an excellent data base for routine and expected transient releases. Specifications for air cleaning can be based on this body of experience with confidence. Specifications for air cleaning in accident situations is another matter. Recent investigations of severe accident behavior are offering a new basis for source terms and air cleaning specifications. Reports by many experts in the field describe an accident environment notably different from previous models. It is an atmosphere heavy with aerosols, both radioactive and inert. Temperatures are sometimes very high; radioiodine is typically in the form of cesium iodide aerosol particles; other nuclides, such as tellurium, are also important aerosols. Some of the present air cleaning requirements may be very important in light of these new accident behavior models. Others may be wasteful or even counterproductive. The use of the new data on accident behavior models to reevaluate requirements promptly is discussed

Source term estimation via monitoring data and its implementation to the RODOS system

International Nuclear Information System (INIS)

Bohunova, J.; Duranova, T.

2000-01-01

A methodology and computer code for interpretation of environmental data, i.e. source term assessment, from on-line environmental monitoring network was developed. The method is based on the conversion of measured dose rates to the source term, i.e. airborne radioactivity release rate, taking into account real meteorological data and location of the monitoring points. The bootstrap estimation methodology and bipivot method to estimate the source term from on-site gamma dose rate monitors is used. The mentioned methods provide an estimate of the mean value of the source term and a confidence interval for it. (author)

Source term estimation during incident response to severe nuclear power plant accidents. Draft

Energy Technology Data Exchange (ETDEWEB)

McKenna, T J; Giitter, J

1987-07-01

The various methods of estimating radionuclide release to the environment (source terms) as a result of an accident at a nuclear power reactor are discussed. The major factors affecting potential radionuclide releases off site (source terms) as a result of nuclear power plant accidents are described. The quantification of these factors based on plant instrumentation also is discussed. A range of accident conditions from those within the design basis to the most severe accidents possible are included in the text. A method of gross estimation of accident source terms and their consequences off site is presented. The goal is to present a method of source term estimation that reflects the current understanding of source term behavior and that can be used during an event. (author)

Source term estimation during incident response to severe nuclear power plant accidents. Draft

International Nuclear Information System (INIS)

McKenna, T.J.; Giitter, J.

1987-01-01

The various methods of estimating radionuclide release to the environment (source terms) as a result of an accident at a nuclear power reactor are discussed. The major factors affecting potential radionuclide releases off site (source terms) as a result of nuclear power plant accidents are described. The quantification of these factors based on plant instrumentation also is discussed. A range of accident conditions from those within the design basis to the most severe accidents possible are included in the text. A method of gross estimation of accident source terms and their consequences off site is presented. The goal is to present a method of source term estimation that reflects the current understanding of source term behavior and that can be used during an event. (author)

Subsurface Shielding Source Term Specification Calculation

International Nuclear Information System (INIS)

S.Su

2001-01-01

The purpose of this calculation is to establish appropriate and defensible waste-package radiation source terms for use in repository subsurface shielding design. This calculation supports the shielding design for the waste emplacement and retrieval system, and subsurface facility system. The objective is to identify the limiting waste package and specify its associated source terms including source strengths and energy spectra. Consistent with the Technical Work Plan for Subsurface Design Section FY 01 Work Activities (CRWMS M and O 2001, p. 15), the scope of work includes the following: (1) Review source terms generated by the Waste Package Department (WPD) for various waste forms and waste package types, and compile them for shielding-specific applications. (2) Determine acceptable waste package specific source terms for use in subsurface shielding design, using a reasonable and defensible methodology that is not unduly conservative. This calculation is associated with the engineering and design activity for the waste emplacement and retrieval system, and subsurface facility system. The technical work plan for this calculation is provided in CRWMS M and O 2001. Development and performance of this calculation conforms to the procedure, AP-3.12Q, Calculations

Spallation Neutron Source Accident Terms for Environmental Impact Statement Input

Energy Technology Data Exchange (ETDEWEB)

Devore, J.R.; Harrington, R.M.

1998-08-01

This report is about accidents with the potential to release radioactive materials into the environment surrounding the Spallation Neutron Source (SNS). As shown in Chap. 2, the inventories of radioactivity at the SNS are dominated by the target facility. Source terms for a wide range of target facility accidents, from anticipated events to worst-case beyond-design-basis events, are provided in Chaps. 3 and 4. The most important criterion applied to these accident source terms is that they should not underestimate potential release. Therefore, conservative methodology was employed for the release estimates. Although the source terms are very conservative, excessive conservatism has been avoided by basing the releases on physical principles. Since it is envisioned that the SNS facility may eventually (after about 10 years) be expanded and modified to support a 4-MW proton beam operational capability, the source terms estimated in this report are applicable to a 4-MW operating proton beam power unless otherwise specified. This is bounding with regard to the 1-MW facility that will be built and operated initially. See further discussion below in Sect. 1.2.

Data assimilation and source term estimation during the early phase of a nuclear accident

Energy Technology Data Exchange (ETDEWEB)

Golubenkov, A.; Borodin, R. [SPA Typhoon, Emergency Centre (Russian Federation); Sohier, A.; Rojas Palma, C. [Centre de l`Etude de l`Energie Nucleaire, Mol (Belgium)

1996-02-01

The mathematical/physical base of possible methods to model the source term during an accidental release of radionuclides is discussed. Knowledge of the source term is important in view of optimizing urgent countermeasures to the population. In most cases however, it will be impossible to assess directly the release dynamics. Therefore methods are under development in which the source term is modelled, based on the comparison of off-site monitoring data and model predictions using an atmospheric dispersion model. The degree of agreement between the measured and calculated characteristics of the radioactive contamination of the air and the ground surface is an important criterion in this process. Due to the inherent complexity, some geometrical transformations taking space-time discrepancies between observed and modelled contamination fields are defined before the source term is adapted. This work describes the developed algorithms which are also tested against data from some tracer experiments performed in the past. This method is also used to reconstruct the dynamics of the Chernobyl source term. Finally this report presents a concept of software to reconstruct a multi-isotopic source term in real-time.

Data assimilation and source term estimation during the early phase of a nuclear accident

International Nuclear Information System (INIS)

Golubenkov, A.; Borodin, R.; Sohier, A.; Rojas Palma, C.

1996-02-01

The mathematical/physical base of possible methods to model the source term during an accidental release of radionuclides is discussed. Knowledge of the source term is important in view of optimizing urgent countermeasures to the population. In most cases however, it will be impossible to assess directly the release dynamics. Therefore methods are under development in which the source term is modelled, based on the comparison of off-site monitoring data and model predictions using an atmospheric dispersion model. The degree of agreement between the measured and calculated characteristics of the radioactive contamination of the air and the ground surface is an important criterion in this process. Due to the inherent complexity, some geometrical transformations taking space-time discrepancies between observed and modelled contamination fields are defined before the source term is adapted. This work describes the developed algorithms which are also tested against data from some tracer experiments performed in the past. This method is also used to reconstruct the dynamics of the Chernobyl source term. Finally this report presents a concept of software to reconstruct a multi-isotopic source term in real-time

Aerosol behavior and light water reactor source terms

International Nuclear Information System (INIS)

Abbey, F.; Schikarski, W.O.

1988-01-01

The major developments in nuclear aerosol modeling following the accident to pressurized water reactor Unit 2 at Three Mile Island are briefly reviewed and the state of the art summarized. The importance and implications of these developments for severe accident source terms for light water reactors are then discussed in general terms. The treatment is not aimed at identifying specific source term values but is intended rather to illustrate trends, to assess the adequacy of the understanding of major aspects of aerosol behavior for source term prediction, and demonstrate in qualitative terms the effect of various aspects of reactor design. Areas where improved understanding of aerosol behavior might lead to further reductions in current source terms predictions are also considered

Probabilistic source term predictions for use with decision support systems

International Nuclear Information System (INIS)

Grindon, E.; Kinniburgh, C.G.

2003-01-01

Full text: Decision Support Systems for use in off-site emergency management, following an incident at a Nuclear Power Plant (NPP) within Europe, are becoming accepted as a useful and appropriate tool to aid decision makers. An area which is not so well developed is the 'upstream' prediction of the source term released into the environment. Rapid prediction of this source term is crucial to the appropriate early management of a nuclear emergency. The initial source term prediction would today be typically based on simple tabulations taking little, or no, account of plant status. It is the interface between the inward looking plant control room team and the outward looking off-site emergency management team that needs to be addressed. This is not an easy proposition as these two distinct disciplines have little common basis from which to communicate their immediate findings and concerns. Within the Euratom Fifth Framework Programme (FP5), complementary approaches are being developed to the pre-release stage; each based on software tools to help bridge this gap. Traditionally source terms (or releases into the environment) provided for use with Decision Support Systems are estimated on a deterministic basis. These approaches use a single, deterministic assumption about plant status. The associated source term represents the 'best estimate' based an available information. No information is provided an the potential for uncertainty in the source term estimate. Using probabilistic methods the outcome is typically a number of possible plant states each with an associated source term and probability. These represent both the best estimate and the spread of the likely source term. However, this is a novel approach and the usefulness of such source term prediction tools is yet to be tested on a wide scale. The benefits of probabilistic source term estimation are presented here; using, as an example, the SPRINT tool developed within the FP5 STERPS project. System for the

Source term model evaluations for the low-level waste facility performance assessment

Energy Technology Data Exchange (ETDEWEB)

Yim, M.S.; Su, S.I. [North Carolina State Univ., Raleigh, NC (United States)

1995-12-31

The estimation of release of radionuclides from various waste forms to the bottom boundary of the waste disposal facility (source term) is one of the most important aspects of LLW facility performance assessment. In this work, several currently used source term models are comparatively evaluated for the release of carbon-14 based on a test case problem. The models compared include PRESTO-EPA-CPG, IMPACTS, DUST and NEFTRAN-II. Major differences in assumptions and approaches between the models are described and key parameters are identified through sensitivity analysis. The source term results from different models are compared and other concerns or suggestions are discussed.

Using Bayesian Belief Network (BBN) modelling for Rapid Source Term Prediction. RASTEP Phase 1

International Nuclear Information System (INIS)

Knochenhauer, M.; Swaling, V.H.; Alfheim, P.

2012-09-01

The project is connected to the development of RASTEP, a computerized source term prediction tool aimed at providing a basis for improving off-site emergency management. RASTEP uses Bayesian belief networks (BBN) to model severe accident progression in a nuclear power plant in combination with pre-calculated source terms (i.e., amount, timing, and pathway of released radio-nuclides). The output is a set of possible source terms with associated probabilities. In the NKS project, a number of complex issues associated with the integration of probabilistic and deterministic analyses are addressed. This includes issues related to the method for estimating source terms, signal validation, and sensitivity analysis. One major task within Phase 1 of the project addressed the problem of how to make the source term module flexible enough to give reliable and valid output throughout the accident scenario. Of the alternatives evaluated, it is recommended that RASTEP is connected to a fast running source term prediction code, e.g., MARS, with a possibility of updating source terms based on real-time observations. (Author)

Using Bayesian Belief Network (BBN) modelling for Rapid Source Term Prediction. RASTEP Phase 1

Energy Technology Data Exchange (ETDEWEB)

Knochenhauer, M.; Swaling, V.H.; Alfheim, P. [Scandpower AB, Sundbyberg (Sweden)

2012-09-15

The project is connected to the development of RASTEP, a computerized source term prediction tool aimed at providing a basis for improving off-site emergency management. RASTEP uses Bayesian belief networks (BBN) to model severe accident progression in a nuclear power plant in combination with pre-calculated source terms (i.e., amount, timing, and pathway of released radio-nuclides). The output is a set of possible source terms with associated probabilities. In the NKS project, a number of complex issues associated with the integration of probabilistic and deterministic analyses are addressed. This includes issues related to the method for estimating source terms, signal validation, and sensitivity analysis. One major task within Phase 1 of the project addressed the problem of how to make the source term module flexible enough to give reliable and valid output throughout the accident scenario. Of the alternatives evaluated, it is recommended that RASTEP is connected to a fast running source term prediction code, e.g., MARS, with a possibility of updating source terms based on real-time observations. (Author)

Some practical implications of source term reassessment

International Nuclear Information System (INIS)

1988-03-01

This report provides a brief summary of the current knowledge of severe accident source terms and suggests how this knowledge might be applied to a number of specific aspects of reactor safety. In preparing the report, consideration has been restricted to source term issues relating to light water reactors (LWRs). Consideration has also generally been restricted to the consequences of hypothetical severe accidents rather than their probability of occurrence, although it is recognized that, in the practical application of source term research, it is necessary to take account of probability as well as consequences. The specific areas identified were as follows: Exploration of the new insights that are available into the management of severe accidents; Investigating the impact of source term research on emergency planning and response; Assessing the possibilities which exist in present reactor designs for preventing or mitigating the consequences of severe accidents and how these might be used effectively; Exploring the need for backfitting and assessing the implications of source term research for future designs; and Improving the quantification of the radiological consequences of hypothetical severe accidents for probabilistic safety assessments (PSAs) and informing the public about the realistic risks associated with nuclear power plants. 7 refs

Revised accident source terms for light-water reactors

Energy Technology Data Exchange (ETDEWEB)

Soffer, L. [Nuclear Regulatory Commission, Washington, DC (United States)

1995-02-01

This paper presents revised accident source terms for light-water reactors incorporating the severe accident research insights gained in this area over the last 15 years. Current LWR reactor accident source terms used for licensing date from 1962 and are contained in Regulatory Guides 1.3 and 1.4. These specify that 100% of the core inventory of noble gases and 25% of the iodine fission products are assumed to be instantaneously available for release from the containment. The chemical form of the iodine fission products is also assumed to be predominantly elemental iodine. These assumptions have strongly affected present nuclear air cleaning requirements by emphasizing rapid actuation of spray systems and filtration systems optimized to retain elemental iodine. A proposed revision of reactor accident source terms and some im implications for nuclear air cleaning requirements was presented at the 22nd DOE/NRC Nuclear Air Cleaning Conference. A draft report was issued by the NRC for comment in July 1992. Extensive comments were received, with the most significant comments involving (a) release fractions for both volatile and non-volatile species in the early in-vessel release phase, (b) gap release fractions of the noble gases, iodine and cesium, and (c) the timing and duration for the release phases. The final source term report is expected to be issued in late 1994. Although the revised source terms are intended primarily for future plants, current nuclear power plants may request use of revised accident source term insights as well in licensing. This paper emphasizes additional information obtained since the 22nd Conference, including studies on fission product removal mechanisms, results obtained from improved severe accident code calculations and resolution of major comments, and their impact upon the revised accident source terms. Revised accident source terms for both BWRS and PWRS are presented.

Revised accident source terms and control room habitability

International Nuclear Information System (INIS)

Lahti, G.P.; Hubner, R.S.; Johnson, W.J.; Schwartz, B.C.

1993-01-01

In April 1992, the NRC staff presented to the Commissioners the draft NUREG open-quotes Revised Accident Source Terms for Light-Water Nuclear Power Plants.close quotes This document is the culmination of more than ten years of NRC-sponsored research and represents the first change in the NRC's position on source terms since TID-14844 was issued in 1962. The purpose of this paper is to investigate the impact of the revised source terms on the current approach to analyzing control room habitability as required by 10 CFR 50. Sample calculations are presented that identify aspects of the model requiring clarification before the implementation of the revised source terms. 6 refs., 4 tabs

NRC source term assessment for incident response dose projections

International Nuclear Information System (INIS)

Easley, P.; Pasedag, W.

1984-01-01

The NRC provides advice and assistance to licensees and State and local authorities in responding to accidents. The TACT code supports this function by providing source term projections for two situations during early (15 to 60 minutes) accident response: (1) Core/containment damage is indicated, but there are no measured releases. Quantification of a predicted release permits emergency response before people are exposed. With TACT, response personnel can estimate releases based on fuel and cladding conditions, coolant boundary and containment integrity, and mitigative systems operability. For this type of estimate, TACT is intermediate between default assumptions and time-consuming mechanistic codes. (2) A combination of plant status and limited release data are available. For this situation, iterations between predictions based on known conditions which are compared to measured releases gives reasonable confidence in supplemental source term information otherwise unavailable: nuclide mix, releases not monitored, and trending or abrupt changes. The assumptions and models used in TACT, and examples of its use, are given in this paper

Advanced Monte Carlo procedure for the IFMIF d-Li neutron source term based on evaluated cross section data

International Nuclear Information System (INIS)

Simakov, S.P.; Fischer, U.; Moellendorff, U. von; Schmuck, I.; Konobeev, A.Yu.; Korovin, Yu.A.; Pereslavtsev, P.

2002-01-01

A newly developed computational procedure is presented for the generation of d-Li source neutrons in Monte Carlo transport calculations based on the use of evaluated double-differential d+ 6,7 Li cross section data. A new code M c DeLicious was developed as an extension to MCNP4C to enable neutronics design calculations for the d-Li based IFMIF neutron source making use of the evaluated deuteron data files. The M c DeLicious code was checked against available experimental data and calculation results of M c DeLi and MCNPX, both of which use built-in analytical models for the Li(d, xn) reaction. It is shown that M c DeLicious along with newly evaluated d+ 6,7 Li data is superior in predicting the characteristics of the d-Li neutron source. As this approach makes use of tabulated Li(d, xn) cross sections, the accuracy of the IFMIF d-Li neutron source term can be steadily improved with more advanced and validated data

Advanced Monte Carlo procedure for the IFMIF d-Li neutron source term based on evaluated cross section data

CERN Document Server

Simakov, S P; Moellendorff, U V; Schmuck, I; Konobeev, A Y; Korovin, Y A; Pereslavtsev, P

2002-01-01

A newly developed computational procedure is presented for the generation of d-Li source neutrons in Monte Carlo transport calculations based on the use of evaluated double-differential d+ sup 6 sup , sup 7 Li cross section data. A new code M sup c DeLicious was developed as an extension to MCNP4C to enable neutronics design calculations for the d-Li based IFMIF neutron source making use of the evaluated deuteron data files. The M sup c DeLicious code was checked against available experimental data and calculation results of M sup c DeLi and MCNPX, both of which use built-in analytical models for the Li(d, xn) reaction. It is shown that M sup c DeLicious along with newly evaluated d+ sup 6 sup , sup 7 Li data is superior in predicting the characteristics of the d-Li neutron source. As this approach makes use of tabulated Li(d, xn) cross sections, the accuracy of the IFMIF d-Li neutron source term can be steadily improved with more advanced and validated data.

Some problems in the categorization of source terms

International Nuclear Information System (INIS)

Abbey, F.; Dunbar, I.H.; Hayns, M.R.; Nixon, W.

1985-01-01

In recent years techniques for calculating source terms have been considerably improved. It would be unfortunate if the new information were to be blurred by the use of old schemes for the categorization of source terms. In the past categorization schemes have been devised without the question of the general principles of categorization and the available options being addressed explicitly. In this paper these principles are set out, providing a framework within which categorization schemes used in past probabilistic risk assessments and possible future improvements are discussed. In particular the use of input from scoping consequence calculations in deciding how to group source terms, and the question of how modelling uncertainties may be expressed as uncertainties in a final category source terms are considered

Source term estimation based on in-situ gamma spectrometry using a high purity germanium detector

International Nuclear Information System (INIS)

Pauly, J.; Rojas-Palma, C.; Sohier, A.

1997-06-01

An alternative method to reconstruct the source term of a nuclear accident is proposed. The technique discussed here involves the use of in-situ gamma spectrometry. The validation of the applied methodology has been possible through the monitoring of routine releases of Ar-41 originating at a Belgian site from an air cooled graphite research reactor. This technique provides a quick nuclide specific decomposition of the source term and therefore will be have an enormous potential if implemented in nuclear emergency preparedness and radiological assessments of nuclear accidents during the early phase

Using Reactive Transport Modeling to Evaluate the Source Term at Yucca Mountain

Energy Technology Data Exchange (ETDEWEB)

Y. Chen

2001-12-19

The conventional approach of source-term evaluation for performance assessment of nuclear waste repositories uses speciation-solubility modeling tools and assumes pure phases of radioelements control their solubility. This assumption may not reflect reality, as most radioelements (except for U) may not form their own pure phases. As a result, solubility limits predicted using the conventional approach are several orders of magnitude higher then the concentrations of radioelements measured in spent fuel dissolution experiments. This paper presents the author's attempt of using a non-conventional approach to evaluate source term of radionuclide release for Yucca Mountain. Based on the general reactive-transport code AREST-CT, a model for spent fuel dissolution and secondary phase precipitation has been constructed. The model accounts for both equilibrium and kinetic reactions. Its predictions have been compared against laboratory experiments and natural analogues. It is found that without calibrations, the simulated results match laboratory and field observations very well in many aspects. More important is the fact that no contradictions between them have been found. This provides confidence in the predictive power of the model. Based on the concept of Np incorporated into uranyl minerals, the model not only predicts a lower Np source-term than that given by conventional Np solubility models, but also produces results which are consistent with laboratory measurements and observations. Moreover, two hypotheses, whether Np enters tertiary uranyl minerals or not, have been tested by comparing model predictions against laboratory observations, the results favor the former. It is concluded that this non-conventional approach of source term evaluation not only eliminates over-conservatism in conventional solubility approach to some extent, but also gives a realistic representation of the system of interest, which is a prerequisite for truly understanding the long-term

Using Reactive Transport Modeling to Evaluate the Source Term at Yucca Mountain

International Nuclear Information System (INIS)

Y. Chen

2001-01-01

The conventional approach of source-term evaluation for performance assessment of nuclear waste repositories uses speciation-solubility modeling tools and assumes pure phases of radioelements control their solubility. This assumption may not reflect reality, as most radioelements (except for U) may not form their own pure phases. As a result, solubility limits predicted using the conventional approach are several orders of magnitude higher then the concentrations of radioelements measured in spent fuel dissolution experiments. This paper presents the author's attempt of using a non-conventional approach to evaluate source term of radionuclide release for Yucca Mountain. Based on the general reactive-transport code AREST-CT, a model for spent fuel dissolution and secondary phase precipitation has been constructed. The model accounts for both equilibrium and kinetic reactions. Its predictions have been compared against laboratory experiments and natural analogues. It is found that without calibrations, the simulated results match laboratory and field observations very well in many aspects. More important is the fact that no contradictions between them have been found. This provides confidence in the predictive power of the model. Based on the concept of Np incorporated into uranyl minerals, the model not only predicts a lower Np source-term than that given by conventional Np solubility models, but also produces results which are consistent with laboratory measurements and observations. Moreover, two hypotheses, whether Np enters tertiary uranyl minerals or not, have been tested by comparing model predictions against laboratory observations, the results favor the former. It is concluded that this non-conventional approach of source term evaluation not only eliminates over-conservatism in conventional solubility approach to some extent, but also gives a realistic representation of the system of interest, which is a prerequisite for truly understanding the long-term

Evaluation of Long-term Performance of Enhanced Anaerobic Source Zone Bioremediation using mass flux

Science.gov (United States)

Haluska, A.; Cho, J.; Hatzinger, P.; Annable, M. D.

2017-12-01

Chlorinated ethene DNAPL source zones in groundwater act as potential long term sources of contamination as they dissolve yielding concentrations well above MCLs, posing an on-going public health risk. Enhanced bioremediation has been applied to treat many source zones with significant promise, but long-term sustainability of this technology has not been thoroughly assessed. This study evaluated the long-term effectiveness of enhanced anaerobic source zone bioremediation at chloroethene contaminated sites to determine if the treatment prevented contaminant rebound and removed NAPL from the source zone. Long-term performance was evaluated based on achieving MCL-based contaminant mass fluxes in parent compound concentrations during different monitoring periods. Groundwater concertation versus time data was compiled for 6-sites and post-remedial contaminant mass flux data was then measured using passive flux meters at wells both within and down-gradient of the source zone. Post-remedial mass flux data was then combined with pre-remedial water quality data to estimate pre-remedial mass flux. This information was used to characterize a DNAPL dissolution source strength function, such as the Power Law Model and the Equilibrium Stream tube model. The six-sites characterized for this study were (1) Former Charleston Air Force Base, Charleston, SC; (2) Dover Air Force Base, Dover, DE; (3) Treasure Island Naval Station, San Francisco, CA; (4) Former Raritan Arsenal, Edison, NJ; (5) Naval Air Station, Jacksonville, FL; and, (6) Former Naval Air Station, Alameda, CA. Contaminant mass fluxes decreased for all the sites by the end of the post-treatment monitoring period and rebound was limited within the source zone. Post remedial source strength function estimates suggest that decreases in contaminant mass flux will continue to occur at these sites, but a mass flux based on MCL levels may never be exceeded. Thus, site clean-up goals should be evaluated as order

Selective application of revised source terms to operating nuclear power plants

International Nuclear Information System (INIS)

Moon, Joo Hyun; Song, Jae Hyuk; Lee, Young Wook; Ko, Hyun Seok; Kang, Chang Sun

2001-01-01

More than 30 years later since 1962 when TID-14844 was promulgated, there has been big change of the US NRC's regulatory position in using accident source terms for radiological assessment following a design basis accident (DBA). To replace the instantaneous source terms of TID-14844, the time-dependent source terms of NUREG-1465 was published in 1995. In the meantime, the radiological acceptance criteria for reactor site evaluation in 10 CFR Part 100 were also revised. In particular, the concept of total effective dose equivalent has been incorporated in accordance with the radiation protection standards set forth in revised 10 CFR Part 20. Subsequently, the publication of Regulatory Guide 1.183 and the revision of Standard Review Plan 15.0.1 followed in 2000, which provided the licensee of operating nuclear power reactor with the acceptable guidance of applying the revised source term. The guidance allowed the holder of an operating license issued prior to January 10, 1997 to voluntarily revise the accident source terms used in the radiological consequence analyses of DBA. Regarding to its type of application, there suggested full and selective applications, Whether it is full or selective, based upon the scope and nature of associated plant modifications being proposed, the actual application of the revised source terms to an operating plant is expected to give a large impact on its facility design basis. Considering scope and cost of the analyses required for licensing, selective application is seemed to be more appealing to an licensee of the operating plant rather than full application. In this paper, hence, the selective application methodology is reviewed and is actally applied to the assessment of offsite radiological consequence following a LOCA at Ulchin Unit 3 and 4, in order to identify and analyze the potential impacts due to application of revised source terms and to assess the considerations taken in each application prior to its actual

Chernobyl source term estimation

International Nuclear Information System (INIS)

Gudiksen, P.H.; Harvey, T.F.; Lange, R.

1990-09-01

The Chernobyl source term available for long-range transport was estimated by integration of radiological measurements with atmospheric dispersion modeling and by reactor core radionuclide inventory estimation in conjunction with WASH-1400 release fractions associated with specific chemical groups. The model simulations revealed that the radioactive cloud became segmented during the first day, with the lower section heading toward Scandinavia and the upper part heading in a southeasterly direction with subsequent transport across Asia to Japan, the North Pacific, and the west coast of North America. By optimizing the agreement between the observed cloud arrival times and duration of peak concentrations measured over Europe, Japan, Kuwait, and the US with the model predicted concentrations, it was possible to derive source term estimates for those radionuclides measured in airborne radioactivity. This was extended to radionuclides that were largely unmeasured in the environment by performing a reactor core radionuclide inventory analysis to obtain release fractions for the various chemical transport groups. These analyses indicated that essentially all of the noble gases, 60% of the radioiodines, 40% of the radiocesium, 10% of the tellurium and about 1% or less of the more refractory elements were released. These estimates are in excellent agreement with those obtained on the basis of worldwide deposition measurements. The Chernobyl source term was several orders of magnitude greater than those associated with the Windscale and TMI reactor accidents. However, the 137 Cs from the Chernobyl event is about 6% of that released by the US and USSR atmospheric nuclear weapon tests, while the 131 I and 90 Sr released by the Chernobyl accident was only about 0.1% of that released by the weapon tests. 13 refs., 2 figs., 7 tabs

Backup Sourcing Decisions for Coping with Supply Disruptions under Long-Term Horizons

Directory of Open Access Journals (Sweden)

Jing Hou

2016-01-01

Full Text Available This paper studies a buyer’s inventory control problem under a long-term horizon. The buyer has one major supplier that is prone to disruption risks and one backup supplier with higher wholesale price. Two kinds of sourcing methods are available for the buyer: single sourcing with/without contingent supply and dual sourcing. In contingent sourcing, the backup supplier is capacitated and/or has yield uncertainty, whereas in dual sourcing the backup supplier has an incentive to offer output flexibility during disrupted periods. The buyer’s expected cost functions and the optimal base-stock levels using each sourcing method under long-term horizon are obtained, respectively. The effects of three risk parameters, disruption probability, contingent capacity or uncertainty, and backup flexibility, are examined using comparative studies and numerical computations. Four sourcing methods, namely, single sourcing with contingent supply, dual sourcing, and single sourcing from either of the two suppliers, are also compared. These findings can be used as a valuable guideline for companies to select an appropriate sourcing strategy under supply disruption risks.

Source term and radiological consequences of the Chernobyl accident

International Nuclear Information System (INIS)

Mourad, R.

1987-09-01

This report presents the results of a study of the source term and radiological consequences of the Chernobyl accident. The results two parts. The first part was performed during the first 2 months following the accident and dealt with the evaluation of the source term and an estimate of individual doses in the European countries outside the Soviet Union. The second part was performed after August 25-29, 1986 when the Soviets presented in a IAEA Conference in Vienna detailed information about the accident, including source term and radiological consequences in the Soviet Union. The second part of the study reconfirms the source term evaluated in the first part and in addition deals with the radiological consequences in the Soviet Union. Source term and individual doses are calculated from measured post-accident data, reported by the Soviet Union and European countries, microcomputer program PEAR (Public Exposure from Accident Releases). 22 refs

Phase 1 immobilized low-activity waste operational source term

International Nuclear Information System (INIS)

Burbank, D.A.

1998-01-01

This report presents an engineering analysis of the Phase 1 privatization feeds to establish an operational source term for storage and disposal of immobilized low-activity waste packages at the Hanford Site. The source term information is needed to establish a preliminary estimate of the numbers of remote-handled and contact-handled waste packages. A discussion of the uncertainties and their impact on the source term and waste package distribution is also presented. It should be noted that this study is concerned with operational impacts only. Source terms used for accident scenarios would differ due to alpha and beta radiation which were not significant in this study

Development of computer-based function to estimate radioactive source term by coupling atmospheric model with monitoring data

International Nuclear Information System (INIS)

Akiko, Furuno; Hideyuki, Kitabata

2003-01-01

Full text: The importance of computer-based decision support systems for local and regional scale accidents has been recognized by many countries with the experiences of accidental atmospheric releases of radionuclides at Chernobyl in 1986 in the former Soviet Union. The recent increase of nuclear power plants in the Asian region also necessitates an emergency response system for Japan to predict the long-range atmospheric dispersion of radionuclides due to overseas accident. On the basis of these backgrounds, WSPEEDI (Worldwide version of System for Prediction of Environmental Emergency Dose Information) at Japan Atomic Energy Research Institute is developed to forecast long-range atmospheric dispersions of radionuclides during nuclear emergency. Although the source condition is critical parameter for accurate prediction, it is rarely that the condition can be acquired in the early stage of overseas accident. Thus, we have been developing a computer-based function to estimate radioactive source term, e.g. the release point, time and amount, as a part of WSPEEDI. This function consists of atmospheric transport simulations and statistical analysis for the prediction and monitoring of air dose rates. Atmospheric transport simulations are carried out for the matrix of possible release points in Eastern Asia and possible release times. The simulation results of air dose rates are compared with monitoring data and the best fitted release condition is defined as source term. This paper describes the source term estimation method and the application to Eastern Asia. The latest version of WSPEEDI accommodates following two models: an atmospheric meteorological model MM5 and a particle random walk model GEARN. MM5 is a non-hydrostatic meteorological model developed by the Pennsylvania State University and the National Center for Atmospheric Research (NCAR). MM5 physically calculates more than 40 meteorological parameters with high resolution in time and space based an

Source term analyses under severe accidents for KNGR

Energy Technology Data Exchange (ETDEWEB)

Song, Yong Mann; Park, Soo Yong

2001-03-01

In this study, in-containment source term for LOFW (Loss of Feed Water), which has appeared the most frequent core melt accident, is calculated and compared with NUREG-1465 source term. This study provides not only new source term data using MELCOR1.8.4 and its state-of-the-art models but also evaluating basis of KNGR design and its mitigation capability under severe accidents. As the selected accident is identical with LOFW-S17, which has been analyzed using MAAP by KEPCO with only difference of 2 SITs, mutual comparison of the results is especially expected.

Recent advances in the source term area within the SARNET European severe accident research network

International Nuclear Information System (INIS)

Herranz, L.E.; Haste, T.; Kärkelä, T.

2015-01-01

Highlights: • Main achievements of source term research in SARNET are given. • Emphasis on the radiologically important iodine and ruthenium fission products. • Conclusions on FP release, transport in the RCS and containment behaviour. • Significance of large-scale integral experiments to validate the analyses used. • A thorough list of the most recent references on source term research results. - Abstract: Source Term has been one of the main research areas addressed within the SARNET network during the 7th EC Framework Programme of EURATOM. The entire source term domain was split into three major areas: oxidising impact on source term, iodine chemistry in the reactor coolant system and containment and data and code assessment. The present paper synthesises the main technical outcome stemming from the SARNET FWP7 project in the area of source term and includes an extensive list of references in which deeper insights on specific issues may be found. Besides, based on the analysis of the current state of the art, an outlook of future source term research is outlined, where major changes in research environment are discussed (i.e., the end of the Phébus FP project; the end of the SARNET projects; and the launch of HORIZON 2020). Most probably research projects will be streamlined towards: release and transport under oxidising conditions, containment chemistry, existing and innovative filtered venting systems and others. These will be in addition to a number of projects that have been completed or are ongoing under different national and international frameworks, like VERDON, CHIP and EPICUR started under the International Source Term Programme (ISTP), the OECD/CSNI programmes BIP, BIP2, STEM, THAI and THAI2, and the French national programme MIRE. The experimental PASSAM project under the 7th EC Framework programme, focused on source term mitigation systems, is highlighted as a good example of a project addressing potential enhancement of safety systems

Recent advances in the source term area within the SARNET European severe accident research network

Energy Technology Data Exchange (ETDEWEB)

Herranz, L.E., E-mail: luisen.herranz@ciemat.es [Centro de Investigaciones Energeticas Medio Ambientales y Tecnologica, CIEMAT, Avda. Complutense 40, E-28040 Madrid (Spain); Haste, T. [Institut de Radioprotection et de Sûreté Nucléaire, IRSN, BP 3, F-13115 St Paul lez Durance Cedex (France); Kärkelä, T. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo (Finland)

2015-07-15

Highlights: • Main achievements of source term research in SARNET are given. • Emphasis on the radiologically important iodine and ruthenium fission products. • Conclusions on FP release, transport in the RCS and containment behaviour. • Significance of large-scale integral experiments to validate the analyses used. • A thorough list of the most recent references on source term research results. - Abstract: Source Term has been one of the main research areas addressed within the SARNET network during the 7th EC Framework Programme of EURATOM. The entire source term domain was split into three major areas: oxidising impact on source term, iodine chemistry in the reactor coolant system and containment and data and code assessment. The present paper synthesises the main technical outcome stemming from the SARNET FWP7 project in the area of source term and includes an extensive list of references in which deeper insights on specific issues may be found. Besides, based on the analysis of the current state of the art, an outlook of future source term research is outlined, where major changes in research environment are discussed (i.e., the end of the Phébus FP project; the end of the SARNET projects; and the launch of HORIZON 2020). Most probably research projects will be streamlined towards: release and transport under oxidising conditions, containment chemistry, existing and innovative filtered venting systems and others. These will be in addition to a number of projects that have been completed or are ongoing under different national and international frameworks, like VERDON, CHIP and EPICUR started under the International Source Term Programme (ISTP), the OECD/CSNI programmes BIP, BIP2, STEM, THAI and THAI2, and the French national programme MIRE. The experimental PASSAM project under the 7th EC Framework programme, focused on source term mitigation systems, is highlighted as a good example of a project addressing potential enhancement of safety systems

A simplified approach to evaluating severe accident source term for PWR

International Nuclear Information System (INIS)

Huang, Gaofeng; Tong, Lili; Cao, Xuewu

2014-01-01

Highlights: • Traditional source term evaluation approaches have been studied. • A simplified approach of source term evaluation for 600 MW PWR is studied. • Five release categories are established. - Abstract: For early design of NPPs, no specific severe accident source term evaluation was considered. Some general source terms have been used for some NPPs. In order to implement a best estimate, a special source term evaluation should be implemented for an NPP. Traditional source term evaluation approaches (mechanism approach and parametric approach) have some difficulties associated with their implementation. The traditional approaches are not consistent with cost-benefit assessment. A simplified approach for evaluating severe accident source term for PWR is studied. For the simplified approach, a simplified containment event tree is established. According to representative cases selection, weighted coefficient evaluation, computation of representative source term cases and weighted computation, five containment release categories are established, including containment bypass, containment isolation failure, containment early failure, containment late failure and intact containment

Radiological and chemical source terms for Solid Waste Operations Complex

International Nuclear Information System (INIS)

Boothe, G.F.

1994-01-01

The purpose of this document is to describe the radiological and chemical source terms for the major projects of the Solid Waste Operations Complex (SWOC), including Project W-112, Project W-133 and Project W-100 (WRAP 2A). For purposes of this document, the term ''source term'' means the design basis inventory. All of the SWOC source terms involve the estimation of the radiological and chemical contents of various waste packages from different waste streams, and the inventories of these packages within facilities or within a scope of operations. The composition of some of the waste is not known precisely; consequently, conservative assumptions were made to ensure that the source term represents a bounding case (i.e., it is expected that the source term would not be exceeded). As better information is obtained on the radiological and chemical contents of waste packages and more accurate facility specific models are developed, this document should be revised as appropriate. Radiological source terms are needed to perform shielding and external dose calculations, to estimate routine airborne releases, to perform release calculations and dose estimates for safety documentation, to calculate the maximum possible fire loss and specific source terms for individual fire areas, etc. Chemical source terms (i.e., inventories of combustible, flammable, explosive or hazardous chemicals) are used to determine combustible loading, fire protection requirements, personnel exposures to hazardous chemicals from routine and accident conditions, and a wide variety of other safety and environmental requirements

Effect of source term composition on offsite doses

International Nuclear Information System (INIS)

Karahalios, P.; Gardner, R.

1985-01-01

The development of new realistic accident source terms has identified the need to establish a basis for comparing the impact of such source terms. This paper attempts to develop a generalized basis of comparison by investigating contributions to offsite acute whole body doses from each group of radionuclides being released to the atmosphere, using CRAC2. The paper also investigates the effect of important parameters such as regional meteorology, sheltering, and duration of release. Finally, the paper focuses on significant changes in the relative importance of individual radionuclide groups in PWR2, SST1, and a revision of the Stone and Webster proposed interim source term

Design parameters and source terms: Volume 3, Source terms: Revision 0

International Nuclear Information System (INIS)

1987-09-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan /endash/ Conceptual Design Report, SCP-CDR. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible salt repository sites

Using Bayesian Belief Network (BBN) modelling for rapid source term prediction. Final report

Energy Technology Data Exchange (ETDEWEB)

Knochenhauer, M.; Swaling, V.H.; Dedda, F.D.; Hansson, F.; Sjoekvist, S.; Sunnegaerd, K. [Lloyd' s Register Consulting AB, Sundbyberg (Sweden)

2013-10-15

The project presented in this report deals with a number of complex issues related to the development of a tool for rapid source term prediction (RASTEP), based on a plant model represented as a Bayesian belief network (BBN) and a source term module which is used for assigning relevant source terms to BBN end states. Thus, RASTEP uses a BBN to model severe accident progression in a nuclear power plant in combination with pre-calculated source terms (i.e., amount, composition, timing, and release path of released radio-nuclides). The output is a set of possible source terms with associated probabilities. One major issue has been associated with the integration of probabilistic and deterministic analyses are addressed, dealing with the challenge of making the source term determination flexible enough to give reliable and valid output throughout the accident scenario. The potential for connecting RASTEP to a fast running source term prediction code has been explored, as well as alternative ways of improving the deterministic connections of the tool. As part of the investigation, a comparison of two deterministic severe accident analysis codes has been performed. A second important task has been to develop a general method where experts' beliefs can be included in a systematic way when defining the conditional probability tables (CPTs) in the BBN. The proposed method includes expert judgement in a systematic way when defining the CPTs of a BBN. Using this iterative method results in a reliable BBN even though expert judgements, with their associated uncertainties, have been used. It also simplifies verification and validation of the considerable amounts of quantitative data included in a BBN. (Author)

Using Bayesian Belief Network (BBN) modelling for rapid source term prediction. Final report

International Nuclear Information System (INIS)

Knochenhauer, M.; Swaling, V.H.; Dedda, F.D.; Hansson, F.; Sjoekvist, S.; Sunnegaerd, K.

2013-10-01

The project presented in this report deals with a number of complex issues related to the development of a tool for rapid source term prediction (RASTEP), based on a plant model represented as a Bayesian belief network (BBN) and a source term module which is used for assigning relevant source terms to BBN end states. Thus, RASTEP uses a BBN to model severe accident progression in a nuclear power plant in combination with pre-calculated source terms (i.e., amount, composition, timing, and release path of released radio-nuclides). The output is a set of possible source terms with associated probabilities. One major issue has been associated with the integration of probabilistic and deterministic analyses are addressed, dealing with the challenge of making the source term determination flexible enough to give reliable and valid output throughout the accident scenario. The potential for connecting RASTEP to a fast running source term prediction code has been explored, as well as alternative ways of improving the deterministic connections of the tool. As part of the investigation, a comparison of two deterministic severe accident analysis codes has been performed. A second important task has been to develop a general method where experts' beliefs can be included in a systematic way when defining the conditional probability tables (CPTs) in the BBN. The proposed method includes expert judgement in a systematic way when defining the CPTs of a BBN. Using this iterative method results in a reliable BBN even though expert judgements, with their associated uncertainties, have been used. It also simplifies verification and validation of the considerable amounts of quantitative data included in a BBN. (Author)

Bayesian source term determination with unknown covariance of measurements

Science.gov (United States)

Belal, Alkomiet; Tichý, Ondřej; Šmídl, Václav

2017-04-01

Determination of a source term of release of a hazardous material into the atmosphere is a very important task for emergency response. We are concerned with the problem of estimation of the source term in the conventional linear inverse problem, y = Mx, where the relationship between the vector of observations y is described using the source-receptor-sensitivity (SRS) matrix M and the unknown source term x. Since the system is typically ill-conditioned, the problem is recast as an optimization problem minR,B(y - Mx)TR-1(y - Mx) + xTB-1x. The first term minimizes the error of the measurements with covariance matrix R, and the second term is a regularization of the source term. There are different types of regularization arising for different choices of matrices R and B, for example, Tikhonov regularization assumes covariance matrix B as the identity matrix multiplied by scalar parameter. In this contribution, we adopt a Bayesian approach to make inference on the unknown source term x as well as unknown R and B. We assume prior on x to be a Gaussian with zero mean and unknown diagonal covariance matrix B. The covariance matrix of the likelihood R is also unknown. We consider two potential choices of the structure of the matrix R. First is the diagonal matrix and the second is a locally correlated structure using information on topology of the measuring network. Since the inference of the model is intractable, iterative variational Bayes algorithm is used for simultaneous estimation of all model parameters. The practical usefulness of our contribution is demonstrated on an application of the resulting algorithm to real data from the European Tracer Experiment (ETEX). This research is supported by EEA/Norwegian Financial Mechanism under project MSMT-28477/2014 Source-Term Determination of Radionuclide Releases by Inverse Atmospheric Dispersion Modelling (STRADI).

Estimation of Source terms for Emergency Planning and Preparedness

Energy Technology Data Exchange (ETDEWEB)

Yi, Chul Un; Chung, Bag Soon; Ahn, Jae Hyun; Yoon, Duk Ho; Jeong, Chul Young; Lim, Jong Dae [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Kang, Sun Gu; Suk, Ho; Park, Sung Kyu; Lim, Hac Kyu; Lee, Kwang Nam [Korea Power Engineering Company Consulting and Architecture Engineers, (Korea, Republic of)

1997-12-31

In this study the severe accident sequences for each plant of concern, which represent accident sequences with a high core damage frequency and significant accident consequences, were selected based on the results of probabilistic safety assessments and source term and time-histories of various safety parameters under severe accidents. Accidents progression analysis for each selected accident sequence was performed by MAAP code. It was determined that the measured values, dose rate and radioisotope concentration, could provide information to the operators on occurrence and timing of core damage, reactor vessel failure, and containment failure during severe accidents. Radioactive concentration in the containment atmosphere, which may be measured by PASS, was estimated. Radioisotope concentration in emergency planning, evaluation of source term behavior in the containment, estimation of core damage degree, analysis of severe accident phenomena, core damage timing, and the amount of radioisotope released to the environment. (author). 50 refs., 60 figs.

Source terms for analysis of accidents at a high level waste repository

International Nuclear Information System (INIS)

Mubayi, V.; Davis, R.E.; Youngblood, R.

1989-01-01

This paper describes an approach to identifying source terms from possible accidents during the preclosure phase of a high-level nuclear waste repository. A review of the literature on repository safety analyses indicated that source term estimation is in a preliminary stage, largely based on judgement-based scoping analyses. The approach developed here was to partition the accident space into domains defined by certain threshold values of temperature and impact energy density which may arise in potential accidents and specify release fractions of various radionuclides, present in the waste form, in each domain. Along with a more quantitative understanding of accident phenomenology, this approach should help in achieving a clearer perspective on scenarios important to preclosure safety assessments of geologic repositories. 18 refs., 3 tabs

Estimation of Source Term Behaviors in SBO Sequence in a Typical 1000MWth PWR and Comparison with Other Source Term Results

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Woon; Han, Seok Jung; Ahn, Kwang Il; Fynan, Douglas; Jung, Yong Hoon [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Since the Three Mile Island (TMI) (1979), Chernobyl (1986), Fukushima Daiichi (2011) accidents, the assessment of radiological source term effects on the environment has been a key concern of nuclear safety. In the Fukushima Daiichi accident, the long-term SBO (station blackout) accident occurs. Using the worst case assumptions like in Fukushima accident on the accident sequences and on the availability of safety systems, the thermal hydraulic behaviors, core relocation and environmental source terms behaviors are estimated for long-term SBO accident for OPR-1000 reactor. MELCOR code version 1.8.6 is used in this analysis. Source term results estimated in this study is compared with other previous studies and estimated results in Fukushima accidents in UNSCEAR-2013 report. This study estimated that 11 % of iodine can be released to environment and 2% of cesium can be released to environment. UNSCEAR-2013 report estimated that 2 - 8 % of iodine have been released to environment and 1 - 3 % of cesium have been released to the environment. They have similar results in the aspect of release fractions of iodine and cesium to environment.

Regulatory Technology Development Plan - Sodium Fast Reactor: Mechanistic Source Term - Trial Calculation

International Nuclear Information System (INIS)

Grabaskas, David

2016-01-01

The potential release of radioactive material during a plant incident, referred to as the source term, is a vital design metric and will be a major focus of advanced reactor licensing. The U.S. Nuclear Regulatory Commission has stated an expectation for advanced reactor vendors to present a mechanistic assessment of the potential source term in their license applications. The mechanistic source term presents an opportunity for vendors to realistically assess the radiological consequences of an incident, and may allow reduced emergency planning zones and smaller plant sites. However, the development of a mechanistic source term for advanced reactors is not without challenges, as there are often numerous phenomena impacting the transportation and retention of radionuclides. This project sought to evaluate U.S. capabilities regarding the mechanistic assessment of radionuclide release from core damage incidents at metal fueled, pool-type sodium fast reactors (SFRs). The purpose of the analysis was to identify, and prioritize, any gaps regarding computational tools or data necessary for the modeling of radionuclide transport and retention phenomena. To accomplish this task, a parallel-path analysis approach was utilized. One path, led by Argonne and Sandia National Laboratories, sought to perform a mechanistic source term assessment using available codes, data, and models, with the goal to identify gaps in the current knowledge base. The second path, performed by an independent contractor, performed sensitivity analyses to determine the importance of particular radionuclides and transport phenomena in regards to offsite consequences. The results of the two pathways were combined to prioritize gaps in current capabilities.

Review of SFR In-Vessel Radiological Source Term Studies

International Nuclear Information System (INIS)

Suk, Soo Dong; Lee, Yong Bum

2008-10-01

An effort has been made in this study to search for and review the literatures in public domain on the studies of the phenomena related to the release of radionuclides and aerosols to the reactor containment of the sodium fast reactor (SFR) plants (i.e., in-vessel source term), made in Japan and Europe including France, Germany and UK over the last few decades. Review work is focused on the experimental programs to investigate the phenomena related to determining the source terms, with a brief review on supporting analytical models and computer programs. In this report, the research programs conducted to investigate the CDA (core disruptive accident) bubble behavior in the sodium pool for determining 'primary' or 'instantaneous' source term are first introduced. The studies performed to determine 'delayed source term' are then described, including the various stages of phenomena and processes: fission product (FP) release from fuel , evaporation release from the surface of the pool, iodine mass transfer from fission gas bubble, FP deposition , and aerosol release from core-concrete interaction. The research programs to investigate the release and transport of FPs and aerosols in the reactor containment (i.e., in-containment source term) are not described in this report

Utility view of the source term and air cleaning

International Nuclear Information System (INIS)

Littlefield, P.S.

1985-01-01

The utility view of the source term and air cleaning is discussed. The source term is made up of: (1) noble gases, which there has been a tendency to ignore in the past because it was thought there was nothing that could be done with them anyway, (2) the halogens, which have been dealt with in Air Cleaning Conferences in the past in terms of charcoal and other systems for removing them, and (3) the solid components of the source term which particulate filters are designed to handle. Air cleaning systems consist of filters, adsorbers, containment sprays, suppression pools in boiling water reactors and ice beds in ice condenser-equipped plants. The feasibility and cost of air cleaning systems are discussed

Low-level radioactive waste performance assessments: Source term modeling

International Nuclear Information System (INIS)

Icenhour, A.S.; Godbee, H.W.; Miller, L.F.

1995-01-01

Low-level radioactive wastes (LLW) generated by government and commercial operations need to be isolated from the environment for at least 300 to 500 yr. Most existing sites for the storage or disposal of LLW employ the shallow-land burial approach. However, the U.S. Department of Energy currently emphasizes the use of engineered systems (e.g., packaging, concrete and metal barriers, and water collection systems). Future commercial LLW disposal sites may include such systems to mitigate radionuclide transport through the biosphere. Performance assessments must be conducted for LUW disposal facilities. These studies include comprehensive evaluations of radionuclide migration from the waste package, through the vadose zone, and within the water table. Atmospheric transport mechanisms are also studied. Figure I illustrates the performance assessment process. Estimates of the release of radionuclides from the waste packages (i.e., source terms) are used for subsequent hydrogeologic calculations required by a performance assessment. Computer models are typically used to describe the complex interactions of water with LLW and to determine the transport of radionuclides. Several commonly used computer programs for evaluating source terms include GWSCREEN, BLT (Breach-Leach-Transport), DUST (Disposal Unit Source Term), BARRIER (Ref. 5), as well as SOURCE1 and SOURCE2 (which are used in this study). The SOURCE1 and SOURCE2 codes were prepared by Rogers and Associates Engineering Corporation for the Oak Ridge National Laboratory (ORNL). SOURCE1 is designed for tumulus-type facilities, and SOURCE2 is tailored for silo, well-in-silo, and trench-type disposal facilities. This paper focuses on the source term for ORNL disposal facilities, and it describes improved computational methods for determining radionuclide transport from waste packages

Analysis of safety information for nuclear power plants and development of source term estimation program

International Nuclear Information System (INIS)

Kim, Tae Woon; Choi, Seong Soo; Park, Jin Hee

1999-12-01

Current CARE(Computerized Advisory System for Radiological Emergency) in KINS(Korea Institute of Nuclear Safety) has no STES(Source Term Estimation System) which links between SIDS(Safety Information Display System) and FADAS(Following Accident Dose Assessment System). So in this study, STES is under development. STES system is the system that estimates the source term based on the safety information provided by SIDS. Estimated source term is given to FADAS as an input for estimation of environmental effect of radiation. Through this first year project STES for the Kori 3,4 and Younggwang 1,2 has been developed. Since there is no CARE for Wolsong(PHWR) plants yet, CARE for Wolsong is under construction. The safety parameters are selected and the safety information display screens and the alarm logic for plant status change are developed for Wolsong Unit 2 based on the design documents for CANDU plants

Literature study of source term research for PWRs

Energy Technology Data Exchange (ETDEWEB)

Sponton, L.L.; NiIsson, Lars

2001-04-01

A literature survey has been carried out in support of ongoing source term calculations with the MELCOR code of some severe accident scenarios for the Swedish Ringhals 2 pressurised water reactor (PWR). The research in the field of severe accidents in power reactors and the source term for subsequent release of radioisotopes was intensified after the Harrisburg accident and has produced a large amount of reports and papers. This survey was therefore limited to research concerning PWR type of reactors and with emphasis on papers related to MELCOR code development. A background is given, relating to some historic documents, and then more recent research after 1990 is reviewed. Of special interest is the ongoing PMbus-programme which is creating new and important results of benefit to the code development and validation of, among others, the MELCOR code. It is concluded that source term calculations involve simulation of many interacting complex physical phenomena, which result in large uncertainties The research has, however, over the years led to considerable improvements Thus has the uncertainty in source term predictions been reduced one to two orders of magnitude from the simpler codes in the early 1980-s to the more realistic codes of today, like MELCOR.

Literature study of source term research for PWRs

International Nuclear Information System (INIS)

Sponton, L.L.; NiIsson, Lars

2001-04-01

A literature survey has been carried out in support of ongoing source term calculations with the MELCOR code of some severe accident scenarios for the Swedish Ringhals 2 pressurised water reactor (PWR). The research in the field of severe accidents in power reactors and the source term for subsequent release of radioisotopes was intensified after the Harrisburg accident and has produced a large amount of reports and papers. This survey was therefore limited to research concerning PWR type of reactors and with emphasis on papers related to MELCOR code development. A background is given, relating to some historic documents, and then more recent research after 1990 is reviewed. Of special interest is the ongoing PMbus-programme which is creating new and important results of benefit to the code development and validation of, among others, the MELCOR code. It is concluded that source term calculations involve simulation of many interacting complex physical phenomena, which result in large uncertainties The research has, however, over the years led to considerable improvements Thus has the uncertainty in source term predictions been reduced one to two orders of magnitude from the simpler codes in the early 1980-s to the more realistic codes of today, like MELCOR

Regulatory impact of nuclear reactor accident source term assumptions. Technical report

International Nuclear Information System (INIS)

Pasedag, W.F.; Blond, R.M.; Jankowski, M.W.

1981-06-01

This report addresses the reactor accident source term implications on accident evaluations, regulations and regulatory requirements, engineered safety features, emergency planning, probabilistic risk assessment, and licensing practice. Assessment of the impact of source term modifications and evaluation of the effects in Design Basis Accident analyses, assuming a change of the chemical form of iodine from elemental to cesium iodide, has been provided. Engineered safety features used in current LWR designs are found to be effective for all postulated combinations of iodine source terms under DBA conditions. In terms of potential accident consequences, it is not expected that the difference in chemical form between elemental iodine and cesium iodide would be significant. In order to account for the current information on source terms, a spectrum of accident scenerios is discussed to realistically estimate the source terms resulting from a range of potential accident conditions

Hazardous constituent source term. Revision 2

International Nuclear Information System (INIS)

1994-01-01

The Department of Energy (DOE) has several facilities that either generate and/or store transuranic (TRU)-waste from weapons program research and production. Much of this waste also contains hazardous waste constituents as regulated under Subtitle C of the Resource Conservation and Recovery Act (RCRA). Toxicity characteristic metals in the waste principally include lead, occurring in leaded rubber gloves and shielding. Other RCRA metals may occur as contaminants in pyrochemical salt, soil, debris, and sludge and solidified liquids, as well as in equipment resulting from decontamination and decommissioning activities. Volatile organic compounds (VOCS) contaminate many waste forms as a residue adsorbed on surfaces or occur in sludge and solidified liquids. Due to the presence of these hazardous constituents, applicable disposal regulations include land disposal restrictions established by Hazardous and Solid Waste Amendments (HSWA). The DOE plans to dispose of TRU-mixed waste from the weapons program in the Waste Isolation Pilot Plant (WIPP) by demonstrating no-migration of hazardous constituents. This paper documents the current technical basis for methodologies proposed to develop a post-closure RCRA hazardous constituent source term. For the purposes of demonstrating no-migration, the hazardous constituent source term is defined as the quantities of hazardous constituents that are available for transport after repository closure. Development of the source term is only one of several activities that will be involved in the no-migration demonstration. The demonstration will also include uncertainty and sensitivity analyses of contaminant transport

Centrifugal Filtration System for Severe Accident Source Term Treatment

Energy Technology Data Exchange (ETDEWEB)

Liu, Shu Chang; Yim, Man Sung [KAIST, Daejeon (Korea, Republic of)

2016-05-15

The objective of this paper is to present the conceptual design of a filtration system that can be used to process airborne severe accident source term. Reactor containment may lose its structural integrity due to over-pressurization during a severe accident. This can lead to uncontrolled radioactive releases to the environment. For preventing the dispersion of these uncontrolled radioactive releases to the environment, several ways to capture or mitigate these radioactive source term releases are under investigation at KAIST. Such technologies are based on concepts like a vortex-like air curtain, a chemical spray, and a suction arm. Treatment of the radioactive material captured by these systems would be required, before releasing to environment. For current filtration systems in the nuclear industry, IAEA lists sand, multi-venturi scrubber, high efficiency particulate arresting (HEPA), charcoal and combinations of the above in NS-G-1-10, 4.143. Most if not all of the requirements of the scenario for applying this technology near the containment of an NPP site and the environmental constraints were analyzed for use in the design of the centrifuge filtration system.

Application of the source term code package to obtain a specific source term for the Laguna Verde Nuclear Power Plant

International Nuclear Information System (INIS)

Souto, F.J.

1991-06-01

The main objective of the project was to use the Source Term Code Package (STCP) to obtain a specific source term for those accident sequences deemed dominant as a result of probabilistic safety analyses (PSA) for the Laguna Verde Nuclear Power Plant (CNLV). The following programme has been carried out to meet this objective: (a) implementation of the STCP, (b) acquisition of specific data for CNLV to execute the STCP, and (c) calculations of specific source terms for accident sequences at CNLV. The STCP has been implemented and validated on CDC 170/815 and CDC 180/860 main frames as well as on a Micro VAX 3800 system. In order to get a plant-specific source term, data on the CNLV including initial core inventory, burn-up, primary containment structures, and materials used for the calculations have been obtained. Because STCP does not explicitly model containment failure, dry well failure in the form of a catastrophic rupture has been assumed. One of the most significant sequences from the point of view of possible off-site risk is the loss of off-site power with failure of the diesel generators and simultaneous loss of high pressure core spray and reactor core isolation cooling systems. The probability for that event is approximately 4.5 x 10 -6 . This sequence has been analysed in detail and the release fractions of radioisotope groups are given in the full report. 18 refs, 4 figs, 3 tabs

Source Term Model for Fine Particle Resuspension from Indoor Surfaces

National Research Council Canada - National Science Library

Kim, Yoojeong; Gidwani, Ashok; Sippola, Mark; Sohn, Chang W

2008-01-01

This Phase I effort developed a source term model for particle resuspension from indoor surfaces to be used as a source term boundary condition for CFD simulation of particle transport and dispersion in a building...

Scoping Analysis of Source Term and Functional Containment Attenuation Factors

Energy Technology Data Exchange (ETDEWEB)

Pete Lowry

2012-10-01

In order to meet future regulatory requirements, the Next Generation Nuclear Plant (NGNP) Project must fully establish and validate the mechanistic modular high temperature gas-cooled reactor (HTGR) source term. This is not possible at this stage in the project, as significant uncertainties in the final design remain unresolved. In the interim, however, there is a need to establish an approximate characterization of the source term. The NGNP team developed a simplified parametric model to establish mechanistic source term estimates for a set of proposed HTGR configurations.

Scoping Analysis of Source Term and Functional Containment Attenuation Factors

Energy Technology Data Exchange (ETDEWEB)

Pete Lowry

2012-02-01

In order to meet future regulatory requirements, the Next Generation Nuclear Plant (NGNP) Project must fully establish and validate the mechanistic modular high temperature gas-cooled reactor (HTGR) source term. This is not possible at this stage in the project, as significant uncertainties in the final design remain unresolved. In the interim, however, there is a need to establish an approximate characterization of the source term. The NGNP team developed a simplified parametric model to establish mechanistic source term estimates for a set of proposed HTGR configurations.

Scoping Analysis of Source Term and Functional Containment Attenuation Factors

Energy Technology Data Exchange (ETDEWEB)

Pete Lowry

2012-01-01

In order to meet future regulatory requirements, the Next Generation Nuclear Plant (NGNP) Project must fully establish and validate the mechanistic modular high temperature gas-cooled reactor (HTGR) source term. This is not possible at this stage in the project, as significant uncertainties in the final design remain unresolved. In the interim, however, there is a need to establish an approximate characterization of the source term. The NGNP team developed a simplified parametric model to establish mechanistic source term estimates for a set of proposed HTGR configurations.

A risk-based evaluation of the impact of key uncertainties on the prediction of severe accident source terms - STU

International Nuclear Information System (INIS)

Ang, M.L.; Grindon, E.; Dutton, L.M.C.; Garcia-Sedano, P.; Santamaria, C.S.; Centner, B.; Auglaire, M.; Routamo, T.; Outa, S.; Jokiniemi, J.; Gustavsson, V.; Wennerstrom, H.; Spanier, L.; Gren, M.; Boschiero, M-H; Droulas, J-L; Friederichs, H-G; Sonnenkalb, M.

2001-01-01

The purpose of this project is to address the key uncertainties associated with a number of fission product release and transport phenomena in a wider context and to assess their relevance to key severe accident sequences. This project is a wide-based analysis involving eight reactor designs that are representative of the reactors currently operating in the European Union (EU). In total, 20 accident sequences covering a wide range of conditions have been chosen to provide the basis for sensitivity studies. The appraisal is achieved through a systematic risk-based framework developed within this project. Specifically, this is a quantitative interpretation of the sensitivity calculations on the basis of 'significance indicators', applied above defined threshold values. These threshold values represent a good surrogate for 'large release', which is defined in a number of EU countries. In addition, the results are placed in the context of in-containment source term limits, for advanced light water reactor designs, as defined by international guidelines. Overall, despite the phenomenological uncertainties, the predicted source terms (both into the containment, and subsequently, into the environment) do not display a high degree of sensitivity to the individual fission product issues addressed in this project. This is due, mainly, to the substantial capacity for the attenuation of airborne fission products by the designed safety provisions and the natural fission product retention mechanisms within the containment

Review of radionuclide source terms used for performance-assessment analyses

International Nuclear Information System (INIS)

Barnard, R.W.

1993-06-01

Two aspects of the radionuclide source terms used for total-system performance assessment (TSPA) analyses have been reviewed. First, a detailed radionuclide inventory (i.e., one in which the reactor type, decay, and burnup are specified) is compared with the standard source-term inventory used in prior analyses. The latter assumes a fixed ratio of pressurized-water reactor (PWR) to boiling-water reactor (BWR) spent fuel, at specific amounts of burnup and at 10-year decay. TSPA analyses have been used to compare the simplified source term with the detailed one. The TSPA-91 analyses did not show a significant difference between the source terms. Second, the radionuclides used in source terms for TSPA aqueous-transport analyses have been reviewed to select ones that are representative of the entire inventory. It is recommended that two actinide decay chains be included (the 4n+2 ''uranium'' and 4n+3 ''actinium'' decay series), since these include several radionuclides that have potentially important release and dose characteristics. In addition, several fission products are recommended for the same reason. The choice of radionuclides should be influenced by other parameter assumptions, such as the solubility and retardation of the radionuclides

Actinide Source Term Program, position paper. Revision 1

International Nuclear Information System (INIS)

Novak, C.F.; Papenguth, H.W.; Crafts, C.C.; Dhooge, N.J.

1994-01-01

The Actinide Source Term represents the quantity of actinides that could be mobilized within WIPP brines and could migrate with the brines away from the disposal room vicinity. This document presents the various proposed methods for estimating this source term, with a particular focus on defining these methods and evaluating the defensibility of the models for mobile actinide concentrations. The conclusions reached in this document are: the 92 PA open-quotes expert panelclose quotes model for mobile actinide concentrations is not defensible; and, although it is extremely conservative, the open-quotes inventory limitsclose quotes model is the only existing defensible model for the actinide source term. The model effort in progress, open-quotes chemical modeling of mobile actinide concentrationsclose quotes, supported by a laboratory effort that is also in progress, is designed to provide a reasonable description of the system and be scientifically realistic and supplant the open-quotes Inventory limitsclose quotes model

The latest results from source term research. Overview and outlook

Energy Technology Data Exchange (ETDEWEB)

Herranz, Luis E. [Centro de Investigaciones Energeticas Medio Ambientales y Tecnologica (CIEMAT), Madrid (Spain); Haste, Tim [Centre d' Etudes de Cadarache, Paul-Lez-Durance (France). Institut de Radioprotection et de Surete Nucleaire (IRSN); Kaerkelae, Teemu [VTT Technical Research Centre of Finland Ltd, Espoo (Finland)

2016-12-15

Source term research has continued internationally for more than 30 years, increasing confidence in calculations of the potential radioactive release to the environment after a severe reactor accident. Important experimental data have been obtained, mainly under international frameworks such as OECD/NEA and EURATOM. Specifically, Phebus FP provides major insights into fission product release and transport. Results are included in severe accident analysis codes. Data from international projects are being interpreted with a view to further improvements in these codes. This paper synthesizes the recent main outcomes from source term research on these topics, and on source term mitigation. It highlights knowledge gaps remaining and discusses ways to proceed. Aside from this further knowledge-driven research, there is consensus on the need to assess the source term predictive ability of current system codes, taking account of scale-up from experiment to reactor conditions.

Regulatory Technology Development Plan - Sodium Fast Reactor: Mechanistic Source Term – Trial Calculation

Energy Technology Data Exchange (ETDEWEB)

Grabaskas, David [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Bucknor, Matthew [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Brunett, Acacia J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Denman, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nuclear Engineering Division; Clark, Andrew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nuclear Engineering Division; Denning, Richard S. [Consultant, Columbus, OH (United States)

2016-10-01

The potential release of radioactive material during a plant incident, referred to as the source term, is a vital design metric and will be a major focus of advanced reactor licensing. The U.S. Nuclear Regulatory Commission has stated an expectation for advanced reactor vendors to present a mechanistic assessment of the potential source term in their license applications. The mechanistic source term presents an opportunity for vendors to realistically assess the radiological consequences of an incident, and may allow reduced emergency planning zones and smaller plant sites. However, the development of a mechanistic source term for advanced reactors is not without challenges, as there are often numerous phenomena impacting the transportation and retention of radionuclides. This project sought to evaluate U.S. capabilities regarding the mechanistic assessment of radionuclide release from core damage incidents at metal fueled, pool-type sodium fast reactors (SFRs). The purpose of the analysis was to identify, and prioritize, any gaps regarding computational tools or data necessary for the modeling of radionuclide transport and retention phenomena. To accomplish this task, a parallel-path analysis approach was utilized. One path, led by Argonne and Sandia National Laboratories, sought to perform a mechanistic source term assessment using available codes, data, and models, with the goal to identify gaps in the current knowledge base. The second path, performed by an independent contractor, performed sensitivity analyses to determine the importance of particular radionuclides and transport phenomena in regards to offsite consequences. The results of the two pathways were combined to prioritize gaps in current capabilities.

Calculations of accelerator-based neutron sources characteristics

International Nuclear Information System (INIS)

Tertytchnyi, R.G.; Shorin, V.S.

2000-01-01

Accelerator-based quasi-monoenergetic neutron sources (T(p,n), D(d;n), T(d;n) and Li (p,n)-reactions) are widely used in experiments on measuring the interaction cross-sections of fast neutrons with nuclei. The present work represents the code for calculation of the yields and spectra of neutrons generated in (p, n)- and ( d; n)-reactions on some targets of light nuclei (D, T; 7 Li). The peculiarities of the stopping processes of charged particles (with incident energy up to 15 MeV) in multilayer and multicomponent targets are taken into account. The code version is made in terms of the 'SOURCE,' a subroutine for the well-known MCNP code. Some calculation results for the most popular accelerator- based neutron sources are given. (authors)

Source terms derived from analyses of hypothetical accidents, 1950-1986

International Nuclear Information System (INIS)

Stratton, W.R.

1987-01-01

This paper reviews the history of reactor accident source term assumptions. After the Three Mile Island accident, a number of theoretical and experimental studies re-examined possible accident sequences and source terms. Some of these results are summarized in this paper

Spent fuel assembly source term parameters

International Nuclear Information System (INIS)

Barrett, P.R.; Foadian, H.; Rashid, Y.R.; Seager, K.D.; Gianoulakis, S.E.

1993-01-01

Containment of cask contents by a transport cask is a function of the cask body, one or more closure lids, and various bolting hardware, and seals associated with the cavity closure and other containment penetrations. In addition, characteristics of cask contents that impede the ability of radionuclides to move from an origin to the external environment also provide containment. In essence, multiple release barriers exist in series in transport casks, and the magnitude of the releasable activity in the cask is considerably lower than the total activity of its contents. A source term approach accounts for the magnitude of the releasable activity available in the cask by assessing the degree of barrier resistance to release provided by material characteristics and inherent barriers that impede the release of radioactive contents. Standardized methodologies for defining the spent-fuel transport packages with specified regulations have recently been developed. An essential part of applying the source term methodology involves characterizing the response of the spent fuel under regulatory conditions of transport. Thermal and structural models of the cask and fuel are analyzed and used to predict fuel rod failure probabilities. Input to these analyses and failure evaluations cover a wide range of geometrical and material properties. An important issue in the development of these models is the sensitivity of the radioactive source term generated during transport to individual parameters such as temperature and fluence level. This paper provides a summary of sensitivity analyses concentrating on the structural response and failure predictions of the spent fuel assemblies

Activities and sources of income after a period of long-term sick leave - a population-based prospective cohort study

Directory of Open Access Journals (Sweden)

Wikman Anders

2012-09-01

Full Text Available Abstract Background There is limited knowledge about what happens to people after long-term sick leave. The aim of this report was to conduct a prospective study of individuals who were on prolonged sick leave during a particular year, considering their activities and sources of income during subsequent years. To enable comparison of different time periods, we used three cohorts of individuals with different starting years. Methods Using data from national registers, three separate cohorts were constructed that included all people living in Sweden who were 20-64 years of age (>5 million in the years 1995, 2000 and 2005, respectively. The individual members of the cohorts were classified into the following groups based on their main source of income and activity in 1995-2008: on long-term sick leave, employed, old-age pensioner, long-term unemployed, disability pensioner, on parental leave, social assistance recipient, student allowance recipient, deceased, or emigrated. Results Most individuals on long-term (> 6 months sick leave in 1995 were not employed 13 years later. Only 11% of the women and 13% of the men were primarily in employment after 13 years. Instead, a wide range of alternatives existed, for example, many had been granted disability pension, and about 10% of the women and 17% of the men had died during the follow-up period. A larger proportion of those with long-term sick leave were back in employment when 2005 was the starting year for the follow-up. Conclusions The low future employment rates for people on long-term sick leave may seem surprising. There are several possible explanations for the finding: The disorders these people may have, might have entailed longstanding difficulties on the labor market. Besides, long-term absence from work, no matter what its causes were, might have worsen the chances of further employment. The economic cycles may also have been of importance. The improving labor market during later years seems

Activities and sources of income after a period of long-term sick leave--a population-based prospective cohort study.

Science.gov (United States)

Wikman, Anders; Wiberg, Michael; Marklund, Staffan; Alexanderson, Kristina

2012-09-06

There is limited knowledge about what happens to people after long-term sick leave. The aim of this report was to conduct a prospective study of individuals who were on prolonged sick leave during a particular year, considering their activities and sources of income during subsequent years. To enable comparison of different time periods, we used three cohorts of individuals with different starting years. Using data from national registers, three separate cohorts were constructed that included all people living in Sweden who were 20-64 years of age (>5 million) in the years 1995, 2000 and 2005, respectively. The individual members of the cohorts were classified into the following groups based on their main source of income and activity in 1995-2008: on long-term sick leave, employed, old-age pensioner, long-term unemployed, disability pensioner, on parental leave, social assistance recipient, student allowance recipient, deceased, or emigrated. Most individuals on long-term (> 6 months) sick leave in 1995 were not employed 13 years later. Only 11% of the women and 13% of the men were primarily in employment after 13 years. Instead, a wide range of alternatives existed, for example, many had been granted disability pension, and about 10% of the women and 17% of the men had died during the follow-up period. A larger proportion of those with long-term sick leave were back in employment when 2005 was the starting year for the follow-up. The low future employment rates for people on long-term sick leave may seem surprising. There are several possible explanations for the finding: The disorders these people may have, might have entailed longstanding difficulties on the labor market. Besides, long-term absence from work, no matter what its causes were, might have worsen the chances of further employment. The economic cycles may also have been of importance. The improving labor market during later years seems to have improved the chances for employment among those earlier

Development of dose calculation program (DBADOSE) incorporating alternative source term due to design basis accident

International Nuclear Information System (INIS)

Bae, Young Jig; Nam, Ki Mun; Lee, Yu Jong; Chung, Chan Young

2003-01-01

Source terms presented in TID-14844 and Regulatory Guide 1.4 have been used for radiological analysis of design basis accidents for licensing existing pressurized water reactor (PWR). However, more realistic and physically-based source term based on results of study and experiments for about 30 years after the publication of TID-14844 was developed and presented in NUREG-1465 published by U.S NRC in 1995. In addition, ICRP has revised dose concepts and criteria through the publication of ICRP-9, 26, 60 and recommended effective dose concepts rather than critical organ concept since the publication of ICRP-26. Accordingly, multipurpose computer program called DBADOSE incorporating alternative source terms in NUREG-1465 and effective dose concepts in ICRP-60 was developed. Comparison of results of DBADOSE with those of POSTDBA and STARDOSE was performed and verified and no significant difference and inaccuracy were found. DBADOSE will be used to evaluate accidental doses for licensing application according to the domestic laws that are expected to be revised in the near future

Development of the methodology for application of revised source term to operating nuclear power plants in Korea

International Nuclear Information System (INIS)

Kang, M.S.; Kang, P.; Kang, C.S.; Moon, J.H.

2004-01-01

Considering the current trend in applying the revised source term proposed by NUREG-1465 to the nuclear power plants in the U.S., it is expected that the revised source term will be applied to the Korean operating nuclear power plants in the near future, even though the exact time can not be estimated. To meet the future technical demands, it is necessary to prepare the technical system including the related regulatory requirements in advance. In this research, therefore, it is intended to develop the methodology to apply the revised source term to operating nuclear power plants in Korea. Several principles were established to develop the application methodologies. First, it is not necessary to modify the existing regulations about source term (i.e., any back-fitting to operating nuclear plants is not necessary). Second, if the pertinent margin of safety is guaranteed, the revised source term suggested by NUREG-1465 may be useful to full application. Finally, a part of revised source term could be selected to application based on the technical feasibility. As the results of this research, several methodologies to apply the revised source term to the Korean operating nuclear power plants have been developed, which include: 1) the selective (or limited) application to use only some of all the characteristics of the revised source term, such as release timing of fission products and chemical form of radio-iodine and 2) the full application to use all the characteristics of the revised source term. The developed methodologies are actually applied to Ulchin 9 and 4 units and their application feasibilities are reviewed. The results of this research are used as either a manual in establishing the plan and the procedure for applying the revised source term to the domestic nuclear plant from the utility's viewpoint; or a technical basis of revising the related regulations from the regulatory body's viewpoint. The application of revised source term to operating nuclear

Inventory and source term evaluation of Russian nuclear power plants for marine applications

International Nuclear Information System (INIS)

Reistad, O.; Oelgaard, P.L.

2006-04-01

This report discusses inventory and source term properties in regard to operation and possible releases due to accidents from Russian marine reactor systems. The first part of the report discusses relevant accidents on the basis of both Russian and western sources. The overview shows that certain vessels were much more accident prone compared to others, in addition, there have been a noteworthy reduction in accidents the last two decades. However, during the last years new types of incidents, such as collisions, has occurred more frequently. The second part of the study considers in detail the most important factors for the source term; reactor operational characteristics and the radionuclide inventory. While Russian icebreakers has been operated on a similar basis as commercial power plants, the submarines has different power cyclograms which results in considerable lower values for fission product inventory. Theoretical values for radionuclide inventory are compared with computed results using the modelling tool HELIOS. Regarding inventory of transuranic elements, the results of the calculations are discussed in detail for selected vessels. Criticality accidents, loss-of-cooling accidents and sinking accidents are considered, bases on actual experiences with these types of accident and on theoretical considerations, and source terms for these accidents are discussed in the last chapter. (au)

Inventory and source term evaluation of Russian nuclear power plants for marine applications

Energy Technology Data Exchange (ETDEWEB)

Reistad, O. [Norwegian Radiation Protection Authority (Norway); Oelgaard, P.L. [Risoe National Lab. (Denmark)

2006-04-15

This report discusses inventory and source term properties in regard to operation and possible releases due to accidents from Russian marine reactor systems. The first part of the report discusses relevant accidents on the basis of both Russian and western sources. The overview shows that certain vessels were much more accident prone compared to others, in addition, there have been a noteworthy reduction in accidents the last two decades. However, during the last years new types of incidents, such as collisions, has occurred more frequently. The second part of the study considers in detail the most important factors for the source term; reactor operational characteristics and the radionuclide inventory. While Russian icebreakers has been operated on a similar basis as commercial power plants, the submarines has different power cyclograms which results in considerable lower values for fission product inventory. Theoretical values for radionuclide inventory are compared with computed results using the modelling tool HELIOS. Regarding inventory of transuranic elements, the results of the calculations are discussed in detail for selected vessels. Criticality accidents, loss-of-cooling accidents and sinking accidents are considered, bases on actual experiences with these types of accident and on theoretical considerations, and source terms for these accidents are discussed in the last chapter. (au)

Equivalent charge source model based iterative maximum neighbor weight for sparse EEG source localization.

Science.gov (United States)

Xu, Peng; Tian, Yin; Lei, Xu; Hu, Xiao; Yao, Dezhong

2008-12-01

How to localize the neural electric activities within brain effectively and precisely from the scalp electroencephalogram (EEG) recordings is a critical issue for current study in clinical neurology and cognitive neuroscience. In this paper, based on the charge source model and the iterative re-weighted strategy, proposed is a new maximum neighbor weight based iterative sparse source imaging method, termed as CMOSS (Charge source model based Maximum neighbOr weight Sparse Solution). Different from the weight used in focal underdetermined system solver (FOCUSS) where the weight for each point in the discrete solution space is independently updated in iterations, the new designed weight for each point in each iteration is determined by the source solution of the last iteration at both the point and its neighbors. Using such a new weight, the next iteration may have a bigger chance to rectify the local source location bias existed in the previous iteration solution. The simulation studies with comparison to FOCUSS and LORETA for various source configurations were conducted on a realistic 3-shell head model, and the results confirmed the validation of CMOSS for sparse EEG source localization. Finally, CMOSS was applied to localize sources elicited in a visual stimuli experiment, and the result was consistent with those source areas involved in visual processing reported in previous studies.

Evolution of source term definition and analysis

International Nuclear Information System (INIS)

Lutz, R.J. Jr.

2004-01-01

The objective of this presentation was to provide an overview of the evolution of accident fission product release analysis methodology and the obtained results; and to provide an overview of the source term implementation analysis in regulatory decisions

Evaluation of short- and long-term fission product sources at the Fukushima Daiichi NPP

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Suzuki, Hiroaki; Okada, Hidetoshi; Pellegrini, Marco; Achilli, Andrea; Hanamoto, Yukio; Sasaki, Hiroaki

2014-01-01

Research on fission product (FP) behaviors used to be one of the most important subjects in water chemistry but it is not done nowadays as a consequence of the increased integrity of nuclear fuels and the minimization of FP release into the environment. Evaluation of FP release into the environment is still one of the key issues for severe accident analysis, though. Although there have been a long quiet period in nuclear safety research, how to detect initiation of severe accidents, how to prevent them and how to mitigate them are still important subjects for nuclear engineering, and how to control the severe accidents after their occurrence, especially how to control FP release into the environment, has seldom been discussed in the water chemistry group recently. The paper is intended to address the issue of fewer activities for FP studies. FP sources are divided into two categories, short- and long-term FP sources. Short-term FP source can be evaluated based on the measured data obtained from monitoring posts (MPs), which give us clear evidence on the importance of radioactive iodine and cesium releases into the environment. It used to be considered that during primary containment vessel (PCV) venting, release of each element, e.g., iodine and cesium, was determined by the suppression pool scrubbing efficiency and most of the cesium would likely be removed in the pool due to its large scrubbing efficiency. But as a result of analyzing the MP data at early stage of the Fukushima Daiichi nuclear power plant (NPP) accident, it was confirmed that the releases of both elements were in proportion to their inventories in the reactors and their scrubbing efficiencies were almost the same. The scrubbing efficiency which increased with the pool water temperature became almost the same for iodine and cesium around the pool water boiling temperature. As a result of the mass balance analysis for FPs in the contaminated water accumulated in the Fukushima Daiichi plant site, it

Inverse kinetics method with source term for subcriticality measurements during criticality approach in the IPEN/MB-01 research reactor

International Nuclear Information System (INIS)

Loureiro, Cesar Augusto Domingues; Santos, Adimir dos

2009-01-01

In reactor physics tests which are performed at the startup after refueling the commercial PWRs, it is important to monitor subcriticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor and it is possible to perform an online reactivity measurement based on the point reactor kinetics equations. This technique is successful applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels, the contribution of the neutron source must be taken into account and this implies the knowledge of a quantity proportional to the source strength, and then it should be determined. Some experiments have been performed in the IPEN/MB-01 Research Reactor for the determination of the Source Term, using the Least Square Inverse Kinetics Method (LSIKM). A digital reactivity meter which neglects the source term is used to calculate the reactivity and then the source term can be determined by the LSIKM. After determining the source term, its value can be added to the algorithm and the reactivity can be determined again, considering the source term. The new digital reactivity meter can be used now to monitor reactivity during the criticality approach and the measured value for the reactivity is more precise than the meter which neglects the source term. (author)

Relevance analysis and short-term prediction of PM2.5 concentrations in Beijing based on multi-source data

Science.gov (United States)

Ni, X. Y.; Huang, H.; Du, W. P.

2017-02-01

The PM2.5 problem is proving to be a major public crisis and is of great public-concern requiring an urgent response. Information about, and prediction of PM2.5 from the perspective of atmospheric dynamic theory is still limited due to the complexity of the formation and development of PM2.5. In this paper, we attempted to realize the relevance analysis and short-term prediction of PM2.5 concentrations in Beijing, China, using multi-source data mining. A correlation analysis model of PM2.5 to physical data (meteorological data, including regional average rainfall, daily mean temperature, average relative humidity, average wind speed, maximum wind speed, and other pollutant concentration data, including CO, NO2, SO2, PM10) and social media data (microblog data) was proposed, based on the Multivariate Statistical Analysis method. The study found that during these factors, the value of average wind speed, the concentrations of CO, NO2, PM10, and the daily number of microblog entries with key words 'Beijing; Air pollution' show high mathematical correlation with PM2.5 concentrations. The correlation analysis was further studied based on a big data's machine learning model- Back Propagation Neural Network (hereinafter referred to as BPNN) model. It was found that the BPNN method performs better in correlation mining. Finally, an Autoregressive Integrated Moving Average (hereinafter referred to as ARIMA) Time Series model was applied in this paper to explore the prediction of PM2.5 in the short-term time series. The predicted results were in good agreement with the observed data. This study is useful for helping realize real-time monitoring, analysis and pre-warning of PM2.5 and it also helps to broaden the application of big data and the multi-source data mining methods.

Determination of source term for Krsko NPP extended fuel cycle

International Nuclear Information System (INIS)

Nemec, T.; Persic, A.; Zagar, T.; Zefran, B.

2004-01-01

The activity and composition of the potential radioactive releases (source term) is important in the decision making about off-site emergency measures in case of a release into environment. Power uprate of Krsko NPP during modernization in 2000 as well as changing of the fuel type and the core design have influenced the source term value. In 2003 a project of 'Jozef Stefan' Institute and Slovenian nuclear safety administration determined a plantspecific source term for new conditions of fuel type and burnup for extended fuel cycle. Calculations of activity and isotopic composition of the core have been performed with ORIGEN-ARP program. Results showed that the core activity for extended 15 months fuel cycle is slightly lower than for the 12 months cycles, mainly due to larger share of fresh fuel. (author)

Accident source terms for boiling water reactors with high burnup cores.

Energy Technology Data Exchange (ETDEWEB)

Gauntt, Randall O.; Powers, Dana Auburn; Leonard, Mark Thomas

2007-11-01

The primary objective of this report is to provide the technical basis for development of recommendations for updates to the NUREG-1465 Source Term for BWRs that will extend its applicability to accidents involving high burnup (HBU) cores. However, a secondary objective is to re-examine the fundamental characteristics of the prescription for fission product release to containment described by NUREG-1465. This secondary objective is motivated by an interest to understand the extent to which research into the release and behaviors of radionuclides under accident conditions has altered best-estimate calculations of the integral response of BWRs to severe core damage sequences and the resulting radiological source terms to containment. This report, therefore, documents specific results of fission product source term analyses that will form the basis for the HBU supplement to NUREG-1465. However, commentary is also provided on observed differences between the composite results of the source term calculations performed here and those reflected NUREG-1465 itself.

Influence of Chemistry on source term assessment

International Nuclear Information System (INIS)

Herranz Puebla, L.E.; Lopez Diez, I.; Rodriguez Maroto, J.J.; Martinez Lopez-Alcorocho, A.

1991-01-01

The major goal of a phenomenology analysis of containment during a severe accident situation can be splitedd into the following ones: to know the containment response to the different loads and to predict accurately the fission product and aerosol behavior. In this report, the main results coming from the study of a hypothetical accident scenario, based on LA-4 experiment of LACE project, are presented. In order to do it, several codes have been coupled: CONTEMPT4/MOD5 (thermalhydraulics), NAUA/MOD5 (aerosol physics) and IODE (iodine chemistry). 12 refs. It has been demonstrated the impossibility of assessing with confidence the Source Term if the chemical conduct of some radionuclides is not taken into account. In particular, the influence on the iodine retention efficiency of the sump of variables such as pH has been proven. (Author). 12 refs

Modelling and simulation the radioactive source-term of fission products in PWR type reactors

International Nuclear Information System (INIS)

Porfirio, Rogilson Nazare da Silva

1996-01-01

The source-term was defined with the purpose the quantify all radioactive nuclides released the nuclear reactor in the case of accidents. Nowadays the source-term is limited to the coolant of the primary circuit of reactors and may be measured or modelled with computer coders such as the TFP developed in this work. The calculational process is based on the linear chain techniques used in the CINDER-2 code. The TFP code considers forms of fission products release from the fuel pellet: Recoil, Knockout and Migration. The release from the gap to the coolant fluid is determined from the ratio between activity measured in the coolant and calculated activity in the gap. Considered the operational data of SURRY-1 reactor, the TFP code was run to obtain the source=term of this reactor. From the measured activities it was verified the reliability level of the model and the employed computational logic. The accuracy of the calculated quantities were compared to the measured data was considered satisfactory. (author)

COMPASS: A source term code for investigating capillary barrier performance

International Nuclear Information System (INIS)

Zhou, Wei; Apted, J.J.

1996-01-01

A computer code COMPASS based on compartment model approach is developed to calculate the near-field source term of the High-Level-Waste repository under unsaturated conditions. COMPASS is applied to evaluate the expected performance of Richard's (capillary) barriers as backfills to divert infiltrating groundwater at Yucca Mountain. Comparing the release rates of four typical nuclides with and without the Richard's barrier, it is shown that the Richard's barrier significantly decreases the peak release rates from the Engineered-Barrier-System (EBS) into the host rock

Directional Unfolded Source Term (DUST) for Compton Cameras.

Energy Technology Data Exchange (ETDEWEB)

Mitchell, Dean J.; Mitchell, Dean J.; Horne, Steven M.; O' Brien, Sean; Thoreson, Gregory G

2018-03-01

A Directional Unfolded Source Term (DUST) algorithm was developed to enable improved spectral analysis capabilities using data collected by Compton cameras. Achieving this objective required modification of the detector response function in the Gamma Detector Response and Analysis Software (GADRAS). Experimental data that were collected in support of this work include measurements of calibration sources at a range of separation distances and cylindrical depleted uranium castings.

Development of source term evaluation method for Korean Next Generation Reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Keon Jae; Cheong, Jae Hak; Park, Jin Baek; Kim, Guk Gee [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1997-10-15

This project had investigate several design features of radioactive waste processing system and method to predict nuclide concentration at primary coolant basic concept of next generation reactor and safety goals at the former phase. In this project several prediction methods of source term are evaluated conglomerately and detailed contents of this project are : model evaluation of nuclide concentration at Reactor Coolant System, evaluation of primary and secondary coolant concentration of reference Nuclear Power Plant(NPP), investigation of prediction parameter of source term evaluation, basic parameter of PWR, operational parameter, respectively, radionuclide removal system and adjustment values of reference NPP, suggestion of source term prediction method of next generation NPP.

Severe accident source term reassessment

International Nuclear Information System (INIS)

Hazzan, M.J.; Gardner, R.; Warman, E.A.; Jacobs, S.B.

1987-01-01

This paper summarizes the status of the reassessment of severe reactor accident source terms, which are defined as the quantity, type, and timing of fission product releases from such accidents. Concentration is on the major results and conclusions of analyses with modern methods for both pressurized water reactors (PWRs) and boiling water reactors (BWRs), and the special case of containment bypass. Some distinctions are drawn between analyses for PWRs and BWRs. In general, the more the matter is examined, the consequences, or probability of serious consequences, seem to be less. (author)

Source term estimation for small sized HTRs

International Nuclear Information System (INIS)

Moormann, R.

1992-08-01

Accidents which have to be considered are core heat-up, reactivity transients, water of air ingress and primary circuit depressurization. The main effort of this paper belongs to water/air ingress and depressurization, which requires consideration of fission product plateout under normal operation conditions; for the latter it is clearly shown, that absorption (penetration) mechanisms are much less important than assumed sometimes in the past. Source term estimation procedures for core heat-up events are shortly reviewed; reactivity transients are apparently covered by them. Besides a general literature survey including identification of areas with insufficient knowledge this paper contains some estimations on the thermomechanical behaviour of fission products in water in air ingress accidents. Typical source term examples are also presented. In an appendix, evaluations of the AVR experiments VAMPYR-I and -II with respect to plateout and fission product filter efficiency are outlined and used for a validation step of the new plateout code SPATRA. (orig.)

Lysimeter data as input to performance assessment source term codes

International Nuclear Information System (INIS)

McConnell, J.W. Jr.; Rogers, R.D.; Sullivan, T.

1992-01-01

The Field Lysimeter Investigation: Low-Level Waste Data Base Development Program is obtaining information on the performance of radioactive waste in a disposal environment. Waste forms fabricated using ion-exchange resins from EPICOR-II c prefilters employed in the cleanup of the Three Mile Island (TMI) Nuclear Power Station are being tested to develop a low-level waste data base and to obtain information on survivability of waste forms in a disposal environment. In this paper, radionuclide releases from waste forms in the first seven years of sampling are presented and discussed. Application of lysimeter data to be used in performance assessment source term models is presented. Initial results from use of data in two models are discussed

Tank waste source term inventory validation. Volume 1. Letter report

International Nuclear Information System (INIS)

Brevick, C.H.; Gaddis, L.A.; Johnson, E.D.

1995-01-01

The sample data for selection of 11 radionuclides and 24 chemical analytes were extracted from six separate sample data sets, were arranged in a tabular format and were plotted on scatter plots for all of the 149 single-shell tanks, the 24 double-shell tanks and the four aging waste tanks. The solid and liquid sample data was placed in separate tables and plots. The sample data and plots were compiled from the following data sets: characterization raw sample data, recent core samples, D. Braun data base, Wastren (Van Vleet) data base, TRAC and HTCE inventories. This document is Volume I of the Letter Report entitled Tank Waste Source Term Inventory Validation

Analysis of the Variability of Classified and Unclassified Radiological Source term Inventories in the Frenchman Flat Area, Nevada test Site

International Nuclear Information System (INIS)

Zhao, P.; Zavarin, M.

2008-01-01

It has been proposed that unclassified source terms used in the reactive transport modeling investigations at NTS CAUs should be based on yield-weighted source terms calculated using the average source term from Bowen et al. (2001) and the unclassified announced yields reported in DOE/NV-209. This unclassified inventory is likely to be used in unclassified contaminant boundary calculations and is, thus, relevant to compare to the classified inventory. They have examined the classified radionuclide inventory produced by 10 underground nuclear tests conducted in the Frenchman Flat (FF) area of the Nevada Test Site. The goals were to (1) evaluate the variability in classified radiological source terms among the 10 tests and (2) compare that variability and inventory uncertainties to an average unclassified inventory (e.g. Bowen 2001). To evaluate source term variability among the 10 tests, radiological inventories were compared on two relative scales: geometric mean and yield-weighted geometric mean. Furthermore, radiological inventories were either decay corrected to a common date (9/23/1992) or the time zero (t 0 ) of each test. Thus, a total of four data sets were produced. The date of 9/23/1992 was chosen based on the date of the last underground nuclear test at the Nevada Test Site

STEPS: source term estimation based on plant status phase 0 - the technical specifications of the containment module

International Nuclear Information System (INIS)

Vamanu, D.V.

1998-01-01

In the framework of Project RODOS (Real-Time On-Line Decision Support System for Nuclear Emergencies in Europe), the European Atomic Energy Community (EAEC) of the Commission of the European Communities has commissioned the development of a unified concept, body of knowledge, models and software package meant to assist the evaluation of the source term of severe nuclear accidents in light water reactors of the types prevailing on the Continent. Code-named STEPS, for 'Source Term Estimation based on Plant Status', the project has evolved as Contract RODOS D (FI4P-CT96-0048), between EAEC and consortium of expert European centres including Commissariat a l'Energie Atomique, Institut de Protection et de Surete Nucleaire, (CEA-DPI-SEAC) as Coordinator and Forschungszentrum Karlsruhe GmbH (FZK-INR), the Finnish Centre for Radiation and Nuclear Safety, (STUK-NSD), the Technical Research Centre of Finland, Energy, Nuclear Energy (VTT-ET-NE), and Eidgenossische Technische Hochschule - ETH Zurich, Centre of Excellence (ETH-CERS) as Contractors. For the Phase 0 of the project, an IFIN-HH expert has been assigned by ETH-CERS to develop the Technical Specifications of the delivery component of the intended STEPS package, the CONTAINMENT Module. Sponsored by ETH-CERS headquarters in Zurich, the work was done on the premises and with the logistic support of CEA D PI-SEAC at Fontenay-aux-Roses, with the feedback processing and computer code development subsequently performed in Bucharest. The Technical Specifications of the STEPS CONTAINMENT Module were guided by specific terms of reference, including: (i) the capability of the software to function as a source term interface between targeted nuclear power plants and the RODOS System; (ii) the comparable capability of the system to be operated as a stand-alone assessment and decision support tool for a comprehensive variety of plants, nuclear emergency classes. On the technical side, the specifications had to focus on the possible

Development of source term evaluation method for Korean Next Generation Reactor(III)

Energy Technology Data Exchange (ETDEWEB)

Lee, Geon Jae; Park, Jin Baek; Lee, Yeong Il; Song, Min Cheonl; Lee, Ho Jin [Korea Advanced Institue of Science and Technology, Taejon (Korea, Republic of)

1998-06-15

This project had investigated irradiation characteristics of MOX fuel method to predict nuclide concentration at primary and secondary coolant using a core containing 100% of all MOX fuel and development of source term evaluation tool. In this study, several prediction methods of source term are evaluated. Detailed contents of this project are : an evaluation of model for nuclear concentration at Reactor Coolant System, evaluation of primary and secondary coolant concentration of reference Nuclear Power Plant using purely MOX fuel, suggestion of source term prediction method of NPP with a core using MOX fuel.

Chernobyl radiocesium in freshwater fish: Long-term dynamics and sources of variation

Energy Technology Data Exchange (ETDEWEB)

Sundbom, M [Uppsala Univ., Dept. of Limnology, Uppsala (Sweden)

2002-04-01

The aim of this thesis was to investigate both the long-term temporal pattern and sources of individual variation for radiocesium in freshwater fish. The basis for the study is time series of {sup 137}Cs activity concentrations in fish from three lakes in the area North-west of Uppsala, Sweden that received considerable amounts of {sup 137}Cs from Chernobyl in may 1986. The lakes were Lake Ekholmssjoen, Lake Flatsjoen and Lake Siggeforasjoen, all small forest lakes, but with different morphometrical and chemical characteristics. The data were collected regularly, usually several times per year, during 1986-2000, using consistent methods. More than 7600 fish individuals from 7 species covering wide size ranges and feeding habits were analysed for {sup 137}Cs. For each fish was the length, weight, sex, and often the stomach contend recorded. The evaluation on long-term trends were based on data from all three lakes, while the study on sources of variation evaluated data from Lake Flatsjoen only. (au)

Chernobyl radiocesium in freshwater fish: Long-term dynamics and sources of variation

International Nuclear Information System (INIS)

Sundbom, M.

2002-01-01

The aim of this thesis was to investigate both the long-term temporal pattern and sources of individual variation for radiocesium in freshwater fish. The basis for the study is time series of 137 Cs activity concentrations in fish from three lakes in the area North-west of Uppsala, Sweden that received considerable amounts of 137 Cs from Chernobyl in may 1986. The lakes were Lake Ekholmssjoen, Lake Flatsjoen and Lake Siggeforasjoen, all small forest lakes, but with different morphometrical and chemical characteristics. The data were collected regularly, usually several times per year, during 1986-2000, using consistent methods. More than 7600 fish individuals from 7 species covering wide size ranges and feeding habits were analysed for 137 Cs. For each fish was the length, weight, sex, and often the stomach contend recorded. The evaluation on long-term trends were based on data from all three lakes, while the study on sources of variation evaluated data from Lake Flatsjoen only. (au)

STACE: Source Term Analyses for Containment Evaluations of transport casks

International Nuclear Information System (INIS)

Seager, K.D.; Gianoulakis, S.E.; Barrett, P.R.; Rashid, Y.R.; Reardon, P.C.

1992-01-01

Following the guidance of ANSI N14.5, the STACE methodology provides a technically defensible means for estimating maximum permissible leakage rates. These containment criteria attempt to reflect the true radiological hazard by performing a detailed examination of the spent fuel, CRUD, and residual contamination contributions to the releasable source term. The evaluation of the spent fuel contribution to the source term has been modeled fairly accurately using the STACE methodology. The structural model predicts the cask drop load history, the mechanical response of the fuel assembly, and the probability of cladding breach. These data are then used to predict the amount of fission gas, volatile species, and fuel fines that are releasable from the cask. There are some areas where data are sparse or lacking (e.g., the quantity and size distribution of fuel rod breaches) in which experimental validation is planned. The CRUD spallation fraction is the major area where no quantitative data has been found; therefore, this also requires experimental validation. In the interim, STACE conservatively assumes a 100% spallation fraction for computing the releasable activity. The source term methodology also conservatively assumes that there is 1 Ci of residual contamination available for release in the transport cask. However, residual contamination is still by far the smallest contributor to the source term activity

Source term determination from subcritical multiplication measurements at Koral-1 reactor

International Nuclear Information System (INIS)

Blazquez, J.B.; Barrado, J.M.

1978-01-01

By using an AmBe neutron source two independent procedures have been settled for the zero-power experimental fast-reactor Coral-1 in order to measure the source term which appears in the point kinetical equations. In the first one, the source term is measured when the reactor is just critical with source by taking advantage of the wide range of the linear approach to critical for Coral-1. In the second one, the measurement is made in subcritical state by making use of the previous calibrated control rods. Several applications are also included such as the measurement of the detector dead time, the determinations of the reactivity of small samples and the shape of the neutron importance of the source. (author)

A Study on Improvement of Algorithm for Source Term Evaluation

International Nuclear Information System (INIS)

Park, Jeong Ho; Park, Do Hyung; Lee, Jae Hee

2010-03-01

The program developed by KAERI for source term assessment of radwastes from the advanced nuclear fuel cycle consists of spent fuel database analysis module, spent fuel arising projection module, and automatic characterization module for radwastes from pyroprocess. To improve the algorithm adopted the developed program, following items were carried out: - development of an algorithm to decrease analysis time for spent fuel database - development of setup routine for a analysis procedure - improvement of interface for spent fuel arising projection module - optimization of data management algorithm needed for massive calculation to estimate source terms of radwastes from advanced fuel cycle The program developed through this study has a capability to perform source term estimation although several spent fuel assemblies with different fuel design, initial enrichment, irradiation history, discharge burnup, and cooling time are processed at the same time in the pyroprocess. It is expected that this program will be very useful for the design of unit process of pyroprocess and disposal system

Tank waste source term inventory validation. Volume II. Letter report

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-04-01

This document comprises Volume II of the Letter Report entitled Tank Waste Source Term Inventory Validation. This volume contains Appendix C, Radionuclide Tables, and Appendix D, Chemical Analyte Tables. The sample data for selection of 11 radionuclides and 24 chemical analytes were extracted from six separate sample data sets, were arranged in a tabular format and were plotted on scatter plots for all of the 149 single-shell tanks, the 24 double-shell tanks and the four aging waste tanks. The solid and liquid sample data was placed in separate tables and plots. The sample data and plots were compiled from the following data sets: characterization raw sample data, recent core samples, D. Braun data base, Wastren (Van Vleet) data base, TRAC and HTCE inventories.

Tank waste source term inventory validation. Volume II. Letter report

International Nuclear Information System (INIS)

1995-04-01

This document comprises Volume II of the Letter Report entitled Tank Waste Source Term Inventory Validation. This volume contains Appendix C, Radionuclide Tables, and Appendix D, Chemical Analyte Tables. The sample data for selection of 11 radionuclides and 24 chemical analytes were extracted from six separate sample data sets, were arranged in a tabular format and were plotted on scatter plots for all of the 149 single-shell tanks, the 24 double-shell tanks and the four aging waste tanks. The solid and liquid sample data was placed in separate tables and plots. The sample data and plots were compiled from the following data sets: characterization raw sample data, recent core samples, D. Braun data base, Wastren (Van Vleet) data base, TRAC and HTCE inventories

Source-term reevaluation for US commercial nuclear power reactors: a status report

International Nuclear Information System (INIS)

Herzenberg, C.L.; Ball, J.R.; Ramaswami, D.

1984-12-01

Only results that had been discussed publicly, had been published in the open literature, or were available in preliminary reports as of September 30, 1984, are included here. More than 20 organizations are participating in source-term programs, which have been undertaken to examine severe accident phenomena in light-water power reactors (including the chemical and physical behavior of fission products under accident conditions), update and reevaluate source terms, and resolve differences between predictions and observations of radiation releases and related phenomena. Results from these source-term activities have been documented in over 100 publications to date

A Source-Term Based Boundary Layer Bleed/Effusion Model for Passive Shock Control

Science.gov (United States)

Baurle, Robert A.; Norris, Andrew T.

2011-01-01

A modeling framework for boundary layer effusion has been developed based on the use of source (or sink) terms instead of the usual practice of specifying bleed directly as a boundary condition. This framework allows the surface boundary condition (i.e. isothermal wall, adiabatic wall, slip wall, etc.) to remain unaltered in the presence of bleed. This approach also lends itself to easily permit the addition of empirical models for second order effects that are not easily accounted for by simply defining effective transpiration values. Two effusion models formulated for supersonic flows have been implemented into this framework; the Doerffer/Bohning law and the Slater formulation. These models were applied to unit problems that contain key aspects of the flow physics applicable to bleed systems designed for hypersonic air-breathing propulsion systems. The ability of each model to predict bulk bleed properties was assessed, as well as the response of the boundary layer as it passes through and downstream of a porous bleed system. The model assessment was performed with and without the presence of shock waves. Three-dimensional CFD simulations that included the geometric details of the porous plate bleed systems were also carried out to supplement the experimental data, and provide additional insights into the bleed flow physics. Overall, both bleed formulations fared well for the tests performed in this study. However, the sample of test problems considered in this effort was not large enough to permit a comprehensive validation of the models.

An investigation of the closure problem applied to reactor accident source terms

International Nuclear Information System (INIS)

Brearley, I.R.; Nixon, W.; Hayns, M.R.

1987-01-01

The closure problem, as considered here, focuses attention on the question of when in current research programmes enough has been learned about the source terms for reactor accident releases. Noting that current research is tending to reduce the estimated magnitude of the aerosol component of atmospheric, accidental releases, several possible criteria for closure are suggested. Moreover, using the reactor accident consequence model CRACUK, the effect of gradually reducing the aerosol release fractions of a pressurized water reactor (PWR2) source term (as defined in the WASH-1400 study) is investigated and the implications of applying the suggested criteria to current source term research discussed. (author)

Source term calculations - Ringhals 2 PWR

International Nuclear Information System (INIS)

Johansson, L.L.

1998-02-01

This project was performed within the fifth and final phase of sub-project RAK-2.1 of the Nordic Co-operative Reactor Safety Program, NKS.RAK-2.1 has also included studies of reflooding of degraded core, recriticality and late phase melt progression. Earlier source term calculations for Swedish nuclear power plants are based on the integral code MAAP. A need was recognised to compare these calculations with calculations done with mechanistic codes. In the present work SCDAP/RELAP5 and CONTAIN were used. Only limited results could be obtained within the frame of RAK-2.1, since many problems were encountered using the SCDAP/RELAP5 code. The main obstacle was the extremely long execution times of the MOD3.1 version, but also some dubious fission product calculations. However, some interesting results were obtained for the studied sequence, a total loss of AC power. The report describes the modelling approach for SCDAP/RELAP5 and CONTAIN, and discusses results for the transient including the event of a surge line creep rupture. The study will probably be completed later, providing that an improved SCDAP/RELAP5 code version becomes available. (au) becomes available. (au)

Source terms: an investigation of uncertainties, magnitudes, and recommendations for research. [PWR; BWR

Energy Technology Data Exchange (ETDEWEB)

Levine, S.; Kaiser, G. D.; Arcieri, W. C.; Firstenberg, H.; Fulford, P. J.; Lam, P. S.; Ritzman, R. L.; Schmidt, E. R.

1982-03-01

The purpose of this document is to assess the state of knowledge and expert opinions that exist about fission product source terms from potential nuclear power plant accidents. This is so that recommendations can be made for research and analyses which have the potential to reduce the uncertainties in these estimated source terms and to derive improved methods for predicting their magnitudes. The main reasons for writing this report are to indicate the major uncertainties involved in defining realistic source terms that could arise from severe reactor accidents, to determine which factors would have the most significant impact on public risks and emergency planning, and to suggest research and analyses that could result in the reduction of these uncertainties. Source terms used in the conventional consequence calculations in the licensing process are not explicitly addressed.

Influence of iodine chemistry on source term assessment

International Nuclear Information System (INIS)

Herranz Puebla, L. E.; Lopez Diez, I.; Rodriguez Maroto, J. J.; Martinez Lopez-Alcorocho, A.

1991-01-01

The major goal of a phenomenology analysis of containment during a severe accident situation can be spitted into the following ones: to know the containment response to the different loads and to predict accurately the fission product and aerosol behavior. In this report, the main results coming from the study of a hypothetical accident scenario, based on LA-4 experiment of LACE project, are presented. In order to do it, several codes have been coupled: CONTEMPT4/MOD5 (thermohydraulics), NAUA/MOD5 (aerosol physics) and IODE (iodine chemistry). It has been demonstrated the impossibility of assessing with confidence the Source Term if the chemical conduct of some radionuclides is not taken into account. In particular, the influence on the iodine retention efficiency of the sump of variables such as pH has been proven. (Author)12 refs

Dose assessments for Greifswald and Cadarache with new source terms from ITER NSSR-1

International Nuclear Information System (INIS)

Raskob, W.; Forschungszentrum Karlsruhe GmbH Technik und Umwelt; Hasemann, I.

1997-08-01

Probabilistic dose assessments for accidental atmospheric releases of various ITER source terms which contain tritium and/or activation products were performed for the sites of Greifswald, Germany, and Cadarache, France. No country specific rules were applied and the input parameters were adapted as far as possible to those used within former ITER studies to achieve a better comparability with site independent dose assessments performed in the frame of ITER. The calculations were based on source terms which, at the first time, contain a combination of tritium and activation products. This allowed a better judgement of the contribution of the individual fusion relevant materials to the total dose. The results were compared to site independent dose limits defined in the frame of ITER. Source terms for two different categories, representing 'extremely unlikely events' (CAT-IV) and 'hypothetical sequences' (CAT-V), were investigated. In no cases, the release scenarios of category CAT-IV exceeded the ITER limits. In addition, early doses from the hypothetical scenarios of type CAT-V were still below 50 mSv or 100 mSv, values which are commonly used as lower reference values for evacuation in many potential home countries of ITER. Only the banning of food products was found to be a potential countermeasure which may affect larger areas. (orig.) [de

Revised reactor accident source terms in the U.S. and implementation for light water reactors

International Nuclear Information System (INIS)

Soffer, L.; Lee, J.Y.

1992-01-01

Current NRC reactor accident source terms used for licensing are contained in Regulatory Guides 1.3 and 1.4 and specify that 100 % of the core inventory of noble gases and 25 % of the iodine fission products are assumed to be instantaneously available for release from the containment. The chemical form of the iodine fission products is also assumed to be predominantly elemental (I 2 ) iodine. These assumptions have strongly affected present nuclear plant designs. Severe accident research results have confirmed that although the current source term is very substantial and has resulted in a very high level of plant capability, the present source term is no longer compatible with a realistic understanding of severe accidents. The NRC has issued a proposed revision of the reactor accident source terms as part of several regulatory activities to incorporate severe accident insights for future plants. A revision to 10 CFR 100 is also being proposed to specify site criteria directly and to eliminate source terms and doses for site evaluation. Reactor source terms will continue to be important in evaluating plant designs. Although intended primarily for future plants, existing and evolutionary power plants may voluntarily apply revised accident source term insights as well in licensing. The proposed revised accident source terms are presented in terms of fission product composition, magnitude, timing and iodine chemical form. Some implications for light water reactors are discussed. (author)

EDF source term reduction project main outcomes and further developments

International Nuclear Information System (INIS)

Ranchoux, Gilles; Bonnefon, Julien; Benfarah, Moez; Wintergerst Matthieu; Gressier, Frederic; Leclercq, Stephanie

2012-09-01

The dose reduction is a strategic purpose for EDF in link with the stakes of, nuclear acceptability, respect of regulation and productivity gains. This consists not only in improving the reactor shutdown organization (time spent in control area, biological shielding,...) but also in improving the radiological state of the unit and the efficiency of the source term reduction operations. Since 2003, EDF has been running an innovative project called 'Source Term Reduction' federating the different EDF research and engineering centers in order to: - participate to the long term view about Radiological Protection issues (international feedback analyses), - develop contamination prediction tools (OSCAR software) suitable for the industrial needs (operating units and EPR design), - develop scientific models useful for the understanding of contamination mechanisms to support the strategic decision processes, - carry on with updating and analyzing of contamination measurements feedback in corrosion products (EMECC and CZT campaigns), - carry on with the operational support at short or middle term by optimizing startup and shutdown processes, pre-oxidation or and by improving purification efficiency or material characteristics. This paper will show in a first part the main 2011 results in occupational exposure (collective and individual dose, RCS index...). In a second part, an overview of the main EDF outcomes of the last 3 years in the field of source term reduction will be presented. Future developments extended to contamination issues in EDF NPPs will be also pointed out in this paper. (authors)

Reevaluation of HFIR source term: Supplement 2

International Nuclear Information System (INIS)

Thomas, W.E.

1986-11-01

The HFIR source term has been reevaluated to assess the impact of the increase in core lifetime from 15 to 24 days. Calculations were made to determine the nuclide activities of the iodines, noble gases, and other fission products. The results show that there is no significant change in off-site dose due to the increased fuel cycle for the release scenario postulated in ORNL-3573

Consideration of emergency source terms for pebble-bed high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Tao, Liu; Jun, Zhao; Jiejuan, Tong; Jianzhu, Cao

2009-01-01

Being the last barrier in the nuclear power plant defense-in-depth strategy, emergency planning (EP) is an integrated project. One of the key elements in this process is emergency source terms selection. Emergency Source terms for light water reactor (LWR) nuclear power plant (NPP) have been introduced in many technical documents, and advanced NPP emergency planning is attracting attention recently. Commercial practices of advanced NPP are undergoing in the world, pebble-bed high-temperature gas-cooled reactor (HTGR) power plant is under construction in China which is considered as a representative of advanced NPP. The paper tries to find some pieces of suggestion from our investigation. The discussion of advanced NPP EP will be summarized first, and then the characteristics of pebble-bed HTGR relating to EP will be described. Finally, PSA insights on emergency source terms selection and current pebble-bed HTGR emergency source terms suggestions are proposed

Evaluation of the LMFBR cover gas source term and synthesis of the associated R and D

International Nuclear Information System (INIS)

Balard, F.; Carluec, B.

1996-01-01

At the end of the seventies and the beginning of the eighties, there appeared a pressing need of experimental results to assess the LMFBR's safety level. Because of the urgency, analytical studies were not systematically undertaken and maximum credible cover gas instantaneous source terms (radionuclides core release fraction) were got directly from crude out-of-pile experiment interpretations. Two types of studies and mock-ups were undertaken depending on the timescale of the phenomena: instantaneous source terms (corresponding to an unlikely energetic core disruptive accident CDA), and delayed ones (tens of minutes to some hours). The experiments performed in this frame are reviewed in this presentation: 1) instantaneous source term: - FAUST experiments: I, Cs, UO2 source terms (FzK, Germany), - FAST experiments : pool depth influence on non volatile source term (USA), - CARAVELLE experiments: nonvolatile source term in SPX1 geometry (CEA, France); 2) delayed source term: - NALA experiments: I, Cs, Sr, UO2 source term (FzK, Germany), - PAVE experiments: I source term (CEA, France), - NACOWA experiments: cover gas aerosols enrichment in I and Cs (FzK, Germany) - other French experiments in COPACABANA and GULLIVER facilities. The volatile fission products release is tightly bound to sodium evaporation and a large part of the fission products is dissolved in the liquid sodium aerosols present in the cover gas. Thus the knowledge of the amount of aerosol release to the cover gas is important for the evaluation of the source term. The maximum credible cover gas instantaneous source terms deduced from the experiments have led to conservative source terms to be taken into account in safety analysis. Nevertheless modelling attempts of the observed (in-pile or out-of-pile) physico-chemical phenomena have been undertaken for extrapolation to the reactor case. The main topics of this theoretical research are as follows: fission products evaporation in the cover gas (Fz

A nuclear source term analysis for spacecraft power systems

International Nuclear Information System (INIS)

McCulloch, W.H.

1998-01-01

All US space missions involving on board nuclear material must be approved by the Office of the President. To be approved the mission and the hardware systems must undergo evaluations of the associated nuclear health and safety risk. One part of these evaluations is the characterization of the source terms, i.e., the estimate of the amount, physical form, and location of nuclear material, which might be released into the environment in the event of credible accidents. This paper presents a brief overview of the source term analysis by the Interagency Nuclear Safety Review Panel for the NASA Cassini Space Mission launched in October 1997. Included is a description of the Energy Interaction Model, an innovative approach to the analysis of potential releases from high velocity impacts resulting from launch aborts and reentries

PFLOTRAN-RepoTREND Source Term Comparison Summary.

Energy Technology Data Exchange (ETDEWEB)

Frederick, Jennifer M

2018-03-01

Code inter-comparison studies are useful exercises to verify and benchmark independently developed software to ensure proper function, especially when the software is used to model high-consequence systems which cannot be physically tested in a fully representative environment. This summary describes the results of the first portion of the code inter-comparison between PFLOTRAN and RepoTREND, which compares the radionuclide source term used in a typical performance assessment.

Low-level waste disposal performance assessments - Total source-term analysis

Energy Technology Data Exchange (ETDEWEB)

Wilhite, E.L.

1995-12-31

Disposal of low-level radioactive waste at Department of Energy (DOE) facilities is regulated by DOE. DOE Order 5820.2A establishes policies, guidelines, and minimum requirements for managing radioactive waste. Requirements for disposal of low-level waste emplaced after September 1988 include providing reasonable assurance of meeting stated performance objectives by completing a radiological performance assessment. Recently, the Defense Nuclear Facilities Safety Board issued Recommendation 94-2, {open_quotes}Conformance with Safety Standards at Department of Energy Low-Level Nuclear Waste and Disposal Sites.{close_quotes} One of the elements of the recommendation is that low-level waste performance assessments do not include the entire source term because low-level waste emplaced prior to September 1988, as well as other DOE sources of radioactivity in the ground, are excluded. DOE has developed and issued guidance for preliminary assessments of the impact of including the total source term in performance assessments. This paper will present issues resulting from the inclusion of all DOE sources of radioactivity in performance assessments of low-level waste disposal facilities.

PLOTLIB: a computerized nuclear waste source-term library storage and retrieval system

International Nuclear Information System (INIS)

Marshall, J.R.; Nowicki, J.A.

1978-01-01

The PLOTLIB code was written to provide computer access to the Nuclear Waste Source-Term Library for those users with little previous computer programming experience. The principles of user orientation, quick accessibility, and versatility were extensively employed in the development of the PLOTLIB code to accomplish this goal. The Nuclear Waste Source-Term Library consists of 16 ORIGEN computer runs incorporating a wide variety of differing light water reactor (LWR) fuel cycles and waste streams. The typical isotopic source-term data consist of information on watts, curies, grams, etc., all of which are compiled as a function of time after reactor discharge and unitized on a per metric ton heavy metal basis. The information retrieval code, PLOTLIB, is used to process source-term information requests into computer plots and/or user-specified output tables. This report will serve both as documentation of the current data library and as an operations manual for the PLOTLIB computer code. The accompanying input description, program listing, and sample problems make this code package an easily understood tool for the various nuclear waste studies under way at the Office of Waste Isolation

Open Source Web Based Geospatial Processing with OMAR

Directory of Open Access Journals (Sweden)

Mark Lucas

2009-01-01

Full Text Available The availability of geospatial data sets is exploding. New satellites, aerial platforms, video feeds, global positioning system tagged digital photos, and traditional GIS information are dramatically increasing across the globe. These raw materials need to be dynamically processed, combined and correlated to generate value added information products to answer a wide range of questions. This article provides an overview of OMAR web based geospatial processing. OMAR is part of the Open Source Software Image Map project under the Open Source Geospatial Foundation. The primary contributors of OSSIM make their livings by providing professional services to US Government agencies and programs. OMAR provides one example that open source software solutions are increasingly being deployed in US government agencies. We will also summarize the capabilities of OMAR and its plans for near term development.

Impact of source terms on distances to which reactor accident consequences occur

International Nuclear Information System (INIS)

Ostmeyer, R.M.

1982-01-01

Estimates of the distances over which reactor accident consequences might occur are important for development of siting criteria and for emergency response planning. This paper summarizes the results of a series of CRAC2 calculations performed to estimate these distances. Because of the current controversy concerning the magnitude of source terms for severe accidents, the impact of source term reductions upon distance estimates is also examined

The long-term problems of contaminated land: Sources, impacts and countermeasures

International Nuclear Information System (INIS)

Baes, C.F. III.

1986-11-01

This report examines the various sources of radiological land contamination; its extent; its impacts on man, agriculture, and the environment; countermeasures for mitigating exposures; radiological standards; alternatives for achieving land decontamination and cleanup; and possible alternatives for utilizing the land. The major potential sources of extensive long-term land contamination with radionuclides, in order of decreasing extent, are nuclear war, detonation of a single nuclear weapon (e.g., a terrorist act), serious reactor accidents, and nonfission nuclear weapons accidents that disperse the nuclear fuels (termed ''broken arrows'')

A source term and risk calculations using level 2+PSA methodology

International Nuclear Information System (INIS)

Park, S. I.; Jea, M. S.; Jeon, K. D.

2002-01-01

The scope of Level 2+ PSA includes the assessment of dose risk which is associated with the exposures of the radioactive nuclides escaping from nuclear power plants during severe accidents. The establishment of data base for the exposure dose in Korea nuclear power plants may contribute to preparing the accident management programs and periodic safety reviews. In this study the ORIGEN, MELCOR and MACCS code were employed to produce a integrated framework to assess the radiation source term risk. The framework was applied to a reference plant. Using IPE results, the dose rate for the reference plant was calculated quantitatively

The Multimedia Environmental Pollutant Assessment System (MEPAS)reg-sign: Source-term release formulations

International Nuclear Information System (INIS)

Streile, G.P.; Shields, K.D.; Stroh, J.L.; Bagaasen, L.M.; Whelan, G.; McDonald, J.P.; Droppo, J.G.; Buck, J.W.

1996-11-01

This report is one of a series of reports that document the mathematical models in the Multimedia Environmental Pollutant Assessment System (MEPAS). Developed by Pacific Northwest National Laboratory for the US Department of Energy, MEPAS is an integrated impact assessment software implementation of physics-based fate and transport models in air, soil, and water media. Outputs are estimates of exposures and health risk assessments for radioactive and hazardous pollutants. Each of the MEPAS formulation documents covers a major MEPAS component such as source-term, atmospheric, vadose zone/groundwater, surface water, and health exposure/health impact assessment. Other MEPAS documentation reports cover the sensitivity/uncertainty formulations and the database parameter constituent property estimation methods. The pollutant source-term release component is documented in this report. MEPAS simulates the release of contaminants from a source, transport through the air, groundwater, surface water, or overland pathways, and transfer through food chains and exposure pathways to the exposed individual or population. For human health impacts, risks are computed for carcinogens and hazard quotients for noncarcinogens. MEPAS is implemented on a desktop computer with a user-friendly interface that allows the user to define the problem, input the required data, and execute the appropriate models for both deterministic and probabilistic analyses

Performance evaluation of a permanent ring magnet based helicon plasma source for negative ion source research

Science.gov (United States)

Pandey, Arun; Bandyopadhyay, M.; Sudhir, Dass; Chakraborty, A.

2017-10-01

Helicon wave heated plasmas are much more efficient in terms of ionization per unit power consumed. A permanent magnet based compact helicon wave heated plasma source is developed in the Institute for Plasma Research, after carefully optimizing the geometry, the frequency of the RF power, and the magnetic field conditions. The HELicon Experiment for Negative ion-I source is the single driver helicon plasma source that is being studied for the development of a large sized, multi-driver negative hydrogen ion source. In this paper, the details about the single driver machine and the results from the characterization of the device are presented. A parametric study at different pressures and magnetic field values using a 13.56 MHz RF source has been carried out in argon plasma, as an initial step towards source characterization. A theoretical model is also presented for the particle and power balance in the plasma. The ambipolar diffusion process taking place in a magnetized helicon plasma is also discussed.

The long-term problems of contaminated land: Sources, impacts and countermeasures

Energy Technology Data Exchange (ETDEWEB)

Baes, C.F. III

1986-11-01

This report examines the various sources of radiological land contamination; its extent; its impacts on man, agriculture, and the environment; countermeasures for mitigating exposures; radiological standards; alternatives for achieving land decontamination and cleanup; and possible alternatives for utilizing the land. The major potential sources of extensive long-term land contamination with radionuclides, in order of decreasing extent, are nuclear war, detonation of a single nuclear weapon (e.g., a terrorist act), serious reactor accidents, and nonfission nuclear weapons accidents that disperse the nuclear fuels (termed ''broken arrows'').

Long-term trends in California mobile source emissions and ambient concentrations of black carbon and organic aerosol.

Science.gov (United States)

McDonald, Brian C; Goldstein, Allen H; Harley, Robert A

2015-04-21

A fuel-based approach is used to assess long-term trends (1970-2010) in mobile source emissions of black carbon (BC) and organic aerosol (OA, including both primary emissions and secondary formation). The main focus of this analysis is the Los Angeles Basin, where a long record of measurements is available to infer trends in ambient concentrations of BC and organic carbon (OC), with OC used here as a proxy for OA. Mobile source emissions and ambient concentrations have decreased similarly, reflecting the importance of on- and off-road engines as sources of BC and OA in urban areas. In 1970, the on-road sector accounted for ∼90% of total mobile source emissions of BC and OA (primary + secondary). Over time, as on-road engine emissions have been controlled, the relative importance of off-road sources has grown. By 2010, off-road engines were estimated to account for 37 ± 20% and 45 ± 16% of total mobile source contributions to BC and OA, respectively, in the Los Angeles area. This study highlights both the success of efforts to control on-road emission sources, and the importance of considering off-road engine and other VOC source contributions when assessing long-term emission and ambient air quality trends.

Mapping of the flux and estimate of the radiation source term of neutron fields generated by the GE PETtrace-8 cyclotron

International Nuclear Information System (INIS)

Benavente Castillo, Jhonny Antonio

2017-01-01

The use of spectrometric techniques in a cyclotron facility is strongly advised for the complete characterization of the neutron radiation field. In recent years, several studies of neutron spectrometry have been carried out at the Cyclotron of the Development Center of Nuclear Technology (CDTN). The main objective of this work is to propose a methodology for mapping of the flux and estimate of the radiation source term of neutron fields generated by the GE PETtrace-8 cyclotron. The method of neutron activation analysis with gold, indium and nickel activation foils was used to measure the activities induced at specific points in the cyclotron bunker. The irradiations of the activation foils were performed using the intermittent irradiation method to optimize the radiation field during 18 F production. The study of the neutron spectrum was performed using three radiation source terms. The first source term was constructed based on data provided by the cyclotron manufacturer using the neutron cross sections of the ENDF/B-VII library. The other two were proposed considering the irradiation process used in the routine of 18 F production. Both radiation source terms used the LA150H proton cross sections and for the 18 O, the cross sections of the physical model CEM03 (Cascade-exciton model) and TENDL (TALYS-based Evaluated Nuclear Data Library) were used. The results of the source terms in relation to the experimental results, in terms of neutron fluence rates, reaction rates and dose equivalent rates, showed that are in the same order of magnitude as those obtained by Ogata et al, Fujibuchi et al, and Gallerani et al., for the same cyclotron; and by Mendez et al. for a different manufacturing cyclotron. The models of the proposed radiation source terms were validated to obtain the spectra generated during the 18 F production when water enriched at 18 O is bombarded with a proton beam of 16.5 MeV. Finally, the model of the LA150H - TENDL - 2015 radiation source term is

Algorithms and analytical solutions for rapidly approximating long-term dispersion from line and area sources

Science.gov (United States)

Barrett, Steven R. H.; Britter, Rex E.

Predicting long-term mean pollutant concentrations in the vicinity of airports, roads and other industrial sources are frequently of concern in regulatory and public health contexts. Many emissions are represented geometrically as ground-level line or area sources. Well developed modelling tools such as AERMOD and ADMS are able to model dispersion from finite (i.e. non-point) sources with considerable accuracy, drawing upon an up-to-date understanding of boundary layer behaviour. Due to mathematical difficulties associated with line and area sources, computationally expensive numerical integration schemes have been developed. For example, some models decompose area sources into a large number of line sources orthogonal to the mean wind direction, for which an analytical (Gaussian) solution exists. Models also employ a time-series approach, which involves computing mean pollutant concentrations for every hour over one or more years of meteorological data. This can give rise to computer runtimes of several days for assessment of a site. While this may be acceptable for assessment of a single industrial complex, airport, etc., this level of computational cost precludes national or international policy assessments at the level of detail available with dispersion modelling. In this paper, we extend previous work [S.R.H. Barrett, R.E. Britter, 2008. Development of algorithms and approximations for rapid operational air quality modelling. Atmospheric Environment 42 (2008) 8105-8111] to line and area sources. We introduce approximations which allow for the development of new analytical solutions for long-term mean dispersion from line and area sources, based on hypergeometric functions. We describe how these solutions can be parameterized from a single point source run from an existing advanced dispersion model, thereby accounting for all processes modelled in the more costly algorithms. The parameterization method combined with the analytical solutions for long-term mean

Calculation of the source term for a S1B-sequence at a VVER-1000 type reactor. Part 1

International Nuclear Information System (INIS)

Sdouz, G.

1990-10-01

The behaviour of the source term in a VVER-1000 type reactor is calculated using the 'Source Term Code Package' (STCP). The input data are based on the russian plant Zaporozhye-5. The selected accident sequence is a small break LOCA in the hot leg followed by loss offsite and onsite electric power (S 1 B-sequence). According to the course of the calculation the results are presented and analyzed for each program. Except for the noble gases all release fractions are lower than 10 -4 . 18 refs., 10 tabs. (Author)

Added Value of uncertainty Estimates of SOurce term and Meteorology (AVESOME)

DEFF Research Database (Denmark)

Sørensen, Jens Havskov; Schönfeldt, Fredrik; Sigg, Robert

In the early phase of a nuclear accident, two large sources of uncertainty exist: one related to the source term and one associated with the meteorological data. Operational methods are being developed in AVESOME for quantitative estimation of uncertainties in atmospheric dispersion prediction.......g. at national meteorological services, the proposed methodology is feasible for real-time use, thereby adding value to decision support. In the recent NKS-B projects MUD, FAUNA and MESO, the implications of meteorological uncertainties for nuclear emergency preparedness and management have been studied...... uncertainty in atmospheric dispersion model forecasting stemming from both the source term and the meteorological data is examined. Ways to implement the uncertainties of forecasting in DSSs, and the impacts on real-time emergency management are described. The proposed methodology allows for efficient real...

A Source Term Calculation for the APR1400 NSSS Auxiliary System Components Using the Modified SHIELD Code

International Nuclear Information System (INIS)

Park, Hong Sik; Kim, Min; Park, Seong Chan; Seo, Jong Tae; Kim, Eun Kee

2005-01-01

The SHIELD code has been used to calculate the source terms of NSSS Auxiliary System (comprising CVCS, SIS, and SCS) components of the OPR1000. Because the code had been developed based upon the SYSTEM80 design and the APR1400 NSSS Auxiliary System design is considerably changed from that of SYSTEM80 or OPR1000, the SHIELD code cannot be used directly for APR1400 radiation design. Thus the hand-calculation is needed for the portion of design changes using the results of the SHIELD code calculation. In this study, the SHIELD code is modified to incorporate the APR1400 design changes and the source term calculation is performed for the APR1400 NSSS Auxiliary System components

SARNET. Severe Accident Research Network - key issues in the area of source term

International Nuclear Information System (INIS)

Giordano, P.; Micaelli, J.C.; Haste, T.; Herranz, L.

2005-01-01

About fifty European organisations integrate in SARNET (Network of Excellence of the EU 6 th Framework Programme) their research capacities in resolve better the most important remaining uncertainties and safety issues concerning existing and future Nuclear Power Plants (NPPs) under hypothetical Severe Accident (SA) conditions. Wishing to maintain a long-lasting cooperation, they conduct three types of activities: integrating activities, spreading of excellence and jointly executed research. This paper summarises the main results obtained by the network after the first year, giving more prominence to those from jointly executed research in the Source Term area. Integrating activities have been performed through different means: the ASTEC integral computer code for severe accident transient modelling, through development of PSA2 methodologies, through the setting of a structure for definition of evolving R and D priorities and through the development of a web-network of data bases that hosts experimental data. Such activities have been facilitated by the development of an Advanced Communication Tool. Concerning spreading of excellence, educational courses covering Severe Accident Analysis Methodology and Level 2 PSA have been set up, to be given in early 2006. A detailed text book on Severe Accident Phenomenology has been designed and agreed amongst SARNET members. A mobility programme for students and young researchers is being developed, some detachments are already completed or in progress, and examples are quoted. Jointly executed research activities concern key issues grouped in the Corium, Containment and Source Term areas. In Source Term, behaviour of the highly radio-toxic ruthenium under oxidising conditions (like air ingress) for HBU and MOX fuel has been investigated. First modelling proposals for ASTEC have been made for oxidation of fuel and of ruthenium. Experiments on transport of highly volatile oxide ruthenium species have been performed. Reactor

The Chernobyl reactor accident source term: Development of a consensus view

International Nuclear Information System (INIS)

Guntay, S.; Powers, D.A.; Devell, L.

1997-01-01

In August 1986, scientists from the former Soviet Union provided the nuclear safety community with an impressively detailed account of what was then known about the Chernobyl accident. This included assessments of the magnitudes, rates, and compositions of radionuclide releases during the ten days following initiation of the accident. A summary report based on the Soviet report, the oral presentations, and the discussions with scientists from various countries was issued by the International Atomic Energy Agency shortly thereafter. Ten years have elapsed since the reactor accident at Chernobyl. A great deal more data is now available concerning the events, phenomena, and processes that took place. The purpose of this document is to examine what is known about the radioactive materials released during the accident. The accident was peculiar in the sense that radioactive materials were released, at least initially, in an exceptionally energetic plume and were transported far from the reactor site. Release of radioactivity from the plant continued for about ten days. A number of more recent publications and results from scientists in Russia and elsewhere have significantly improved our understanding of the Chernobyl source term. Because of the special features of the reactor design and the pecularities of the Chernobyl accident, the source term for the Chernobyl accident is of limited applicability of the safety analysis of other types of reactors

Parameterizing unresolved obstacles with source terms in wave modeling: A real-world application

Science.gov (United States)

Mentaschi, Lorenzo; Kakoulaki, Georgia; Vousdoukas, Michalis; Voukouvalas, Evangelos; Feyen, Luc; Besio, Giovanni

2018-06-01

Parameterizing the dissipative effects of small, unresolved coastal features, is fundamental to improve the skills of wave models. The established technique to deal with this problem consists in reducing the amount of energy advected within the propagation scheme, and is currently available only for regular grids. To find a more general approach, Mentaschi et al., 2015b formulated a technique based on source terms, and validated it on synthetic case studies. This technique separates the parameterization of the unresolved features from the energy advection, and can therefore be applied to any numerical scheme and to any type of mesh. Here we developed an open-source library for the estimation of the transparency coefficients needed by this approach, from bathymetric data and for any type of mesh. The spectral wave model WAVEWATCH III was used to show that in a real-world domain, such as the Caribbean Sea, the proposed approach has skills comparable and sometimes better than the established propagation-based technique.

Design parameters and source terms: Volume 1, Design parameters: Revision 0

International Nuclear Information System (INIS)

1987-10-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository in Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites

Coarse Grid Modeling of Turbine Film Cooling Flows Using Volumetric Source Terms

Science.gov (United States)

Heidmann, James D.; Hunter, Scott D.

2001-01-01

The recent trend in numerical modeling of turbine film cooling flows has been toward higher fidelity grids and more complex geometries. This trend has been enabled by the rapid increase in computing power available to researchers. However, the turbine design community requires fast turnaround time in its design computations, rendering these comprehensive simulations ineffective in the design cycle. The present study describes a methodology for implementing a volumetric source term distribution in a coarse grid calculation that can model the small-scale and three-dimensional effects present in turbine film cooling flows. This model could be implemented in turbine design codes or in multistage turbomachinery codes such as APNASA, where the computational grid size may be larger than the film hole size. Detailed computations of a single row of 35 deg round holes on a flat plate have been obtained for blowing ratios of 0.5, 0.8, and 1.0, and density ratios of 1.0 and 2.0 using a multiblock grid system to resolve the flows on both sides of the plate as well as inside the hole itself. These detailed flow fields were spatially averaged to generate a field of volumetric source terms for each conservative flow variable. Solutions were also obtained using three coarse grids having streamwise and spanwise grid spacings of 3d, 1d, and d/3. These coarse grid solutions used the integrated hole exit mass, momentum, energy, and turbulence quantities from the detailed solutions as volumetric source terms. It is shown that a uniform source term addition over a distance from the wall on the order of the hole diameter is able to predict adiabatic film effectiveness better than a near-wall source term model, while strictly enforcing correct values of integrated boundary layer quantities.

Selected source term topics. Report to CSNI by an OECD/NEA Group of experts

International Nuclear Information System (INIS)

1987-04-01

CSNI Report 136 summarizes the results of the work performed by the Group of Experts on the Source Term and Environmental Consequences (PWG4) during the period extending from 1983 and 1986. This report is complementary to Part 1, 'Technical Status of the Source Term' of CSNI Report 135, 'Report to CSNI on Source Term Assessment, Containment atmosphere control systems, and accident consequences'; it considers in detail a number of very specific issues thought to be important in the source term area. It consists of: an executive summary (prepared by the Chairman of the Group), a section on conclusions and recommendations, and five technical chapters (fission product chemistry in the primary circuit of a LWR during severe accidents; resuspension/re-entrainment of aerosols in LWRs following a meltdown accident; iodine chemistry under severe accident conditions; effects of combustion, steam explosions and pressurized melt ejection on fission product behaviour; radionuclide removal by pool scrubbing), a technical annex and two appendices

Source-term model for the SYVAC3-NSURE performance assessment code

International Nuclear Information System (INIS)

Rowat, J.H.; Rattan, D.S.; Dolinar, G.M.

1996-11-01

Radionuclide contaminants in wastes emplaced in disposal facilities will not remain in those facilities indefinitely. Engineered barriers will eventually degrade, allowing radioactivity to escape from the vault. The radionuclide release rate from a low-level radioactive waste (LLRW) disposal facility, the source term, is a key component in the performance assessment of the disposal system. This report describes the source-term model that has been implemented in Ver. 1.03 of the SYVAC3-NSURE (Systems Variability Analysis Code generation 3-Near Surface Repository) code. NSURE is a performance assessment code that evaluates the impact of near-surface disposal of LLRW through the groundwater pathway. The source-term model described here was developed for the Intrusion Resistant Underground Structure (IRUS) disposal facility, which is a vault that is to be located in the unsaturated overburden at AECL's Chalk River Laboratories. The processes included in the vault model are roof and waste package performance, and diffusion, advection and sorption of radionuclides in the vault backfill. The model presented here was developed for the IRUS vault; however, it is applicable to other near-surface disposal facilities. (author). 40 refs., 6 figs

Moving-Horizon Modulating Functions-Based Algorithm for Online Source Estimation in a First Order Hyperbolic PDE

KAUST Repository

Asiri, Sharefa M.; Elmetennani, Shahrazed; Laleg-Kirati, Taous-Meriem

2017-01-01

In this paper, an on-line estimation algorithm of the source term in a first order hyperbolic PDE is proposed. This equation describes heat transport dynamics in concentrated solar collectors where the source term represents the received energy. This energy depends on the solar irradiance intensity and the collector characteristics affected by the environmental changes. Control strategies are usually used to enhance the efficiency of heat production; however, these strategies often depend on the source term which is highly affected by the external working conditions. Hence, efficient source estimation methods are required. The proposed algorithm is based on modulating functions method where a moving horizon strategy is introduced. Numerical results are provided to illustrate the performance of the proposed estimator in open and closed loops.

Moving-Horizon Modulating Functions-Based Algorithm for Online Source Estimation in a First Order Hyperbolic PDE

KAUST Repository

Asiri, Sharefa M.

2017-08-22

In this paper, an on-line estimation algorithm of the source term in a first order hyperbolic PDE is proposed. This equation describes heat transport dynamics in concentrated solar collectors where the source term represents the received energy. This energy depends on the solar irradiance intensity and the collector characteristics affected by the environmental changes. Control strategies are usually used to enhance the efficiency of heat production; however, these strategies often depend on the source term which is highly affected by the external working conditions. Hence, efficient source estimation methods are required. The proposed algorithm is based on modulating functions method where a moving horizon strategy is introduced. Numerical results are provided to illustrate the performance of the proposed estimator in open and closed loops.

Regulatory Technology Development Plan - Sodium Fast Reactor. Mechanistic Source Term - Metal Fuel Radionuclide Release

International Nuclear Information System (INIS)

Grabaskas, David; Bucknor, Matthew; Jerden, James

2016-01-01

The development of an accurate and defensible mechanistic source term will be vital for the future licensing efforts of metal fuel, pool-type sodium fast reactors. To assist in the creation of a comprehensive mechanistic source term, the current effort sought to estimate the release fraction of radionuclides from metal fuel pins to the primary sodium coolant during fuel pin failures at a variety of temperature conditions. These release estimates were based on the findings of an extensive literature search, which reviewed past experimentation and reactor fuel damage accidents. Data sources for each radionuclide of interest were reviewed to establish release fractions, along with possible release dependencies, and the corresponding uncertainty levels. Although the current knowledge base is substantial, and radionuclide release fractions were established for the elements deemed important for the determination of offsite consequences following a reactor accident, gaps were found pertaining to several radionuclides. First, there is uncertainty regarding the transport behavior of several radionuclides (iodine, barium, strontium, tellurium, and europium) during metal fuel irradiation to high burnup levels. The migration of these radionuclides within the fuel matrix and bond sodium region can greatly affect their release during pin failure incidents. Post-irradiation examination of existing high burnup metal fuel can likely resolve this knowledge gap. Second, data regarding the radionuclide release from molten high burnup metal fuel in sodium is sparse, which makes the assessment of radionuclide release from fuel melting accidents at high fuel burnup levels difficult. This gap could be addressed through fuel melting experimentation with samples from the existing high burnup metal fuel inventory.

Regulatory Technology Development Plan - Sodium Fast Reactor. Mechanistic Source Term - Metal Fuel Radionuclide Release

Energy Technology Data Exchange (ETDEWEB)

Grabaskas, David [Argonne National Lab. (ANL), Argonne, IL (United States); Bucknor, Matthew [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-02-01

The development of an accurate and defensible mechanistic source term will be vital for the future licensing efforts of metal fuel, pool-type sodium fast reactors. To assist in the creation of a comprehensive mechanistic source term, the current effort sought to estimate the release fraction of radionuclides from metal fuel pins to the primary sodium coolant during fuel pin failures at a variety of temperature conditions. These release estimates were based on the findings of an extensive literature search, which reviewed past experimentation and reactor fuel damage accidents. Data sources for each radionuclide of interest were reviewed to establish release fractions, along with possible release dependencies, and the corresponding uncertainty levels. Although the current knowledge base is substantial, and radionuclide release fractions were established for the elements deemed important for the determination of offsite consequences following a reactor accident, gaps were found pertaining to several radionuclides. First, there is uncertainty regarding the transport behavior of several radionuclides (iodine, barium, strontium, tellurium, and europium) during metal fuel irradiation to high burnup levels. The migration of these radionuclides within the fuel matrix and bond sodium region can greatly affect their release during pin failure incidents. Post-irradiation examination of existing high burnup metal fuel can likely resolve this knowledge gap. Second, data regarding the radionuclide release from molten high burnup metal fuel in sodium is sparse, which makes the assessment of radionuclide release from fuel melting accidents at high fuel burnup levels difficult. This gap could be addressed through fuel melting experimentation with samples from the existing high burnup metal fuel inventory.

Considerations about source term now used aiming to emergency planning

International Nuclear Information System (INIS)

Austregesilo Filho, H.

1987-01-01

The applicability of source terms, in parametric studies for improving external emergengy plan for Angra-I reactor is presented. The source term is defined as, the quantity and radioactive material disposable for releasing to the environment in case of austere accident in a nuclear power plant. The following hypothesis: occuring accident, 100% of the noble gases, 50% of halogens and 1% of solid fission products contained into the reactor core, are released immediately toward the containment building; the radioactivity releasing to the environment is done at a constant rate of 0.1% in mass per day; the actuation of mitigated systems of radioactivity releasing, such as, spray of container or system of air recirculation by filters, is not considered; and the releasing is done at soil level. (M.C.K.) [pt

A note on variational multiscale methods for high-contrast heterogeneous porous media flows with rough source terms

KAUST Repository

Calo, Victor M.

2011-09-01

In this short note, we discuss variational multiscale methods for solving porous media flows in high-contrast heterogeneous media with rough source terms. Our objective is to separate, as much as possible, subgrid effects induced by the media properties from those due to heterogeneous source terms. For this reason, enriched coarse spaces designed for high-contrast multiscale problems are used to represent the effects of heterogeneities of the media. Furthermore, rough source terms are captured via auxiliary correction equations that appear in the formulation of variational multiscale methods [23]. These auxiliary equations are localized and one can use additive or multiplicative constructions for the subgrid corrections as discussed in the current paper. Our preliminary numerical results show that one can capture the effects due to both spatial heterogeneities in the coefficients (such as permeability field) and source terms (e.g., due to singular well terms) in one iteration. We test the cases for both smooth source terms and rough source terms and show that with the multiplicative correction, the numerical approximations are more accurate compared to the additive correction. © 2010 Elsevier Ltd.

Blind Separation of Nonstationary Sources Based on Spatial Time-Frequency Distributions

Directory of Open Access Journals (Sweden)

Zhang Yimin

2006-01-01

Full Text Available Blind source separation (BSS based on spatial time-frequency distributions (STFDs provides improved performance over blind source separation methods based on second-order statistics, when dealing with signals that are localized in the time-frequency (t-f domain. In this paper, we propose the use of STFD matrices for both whitening and recovery of the mixing matrix, which are two stages commonly required in many BSS methods, to provide robust BSS performance to noise. In addition, a simple method is proposed to select the auto- and cross-term regions of time-frequency distribution (TFD. To further improve the BSS performance, t-f grouping techniques are introduced to reduce the number of signals under consideration, and to allow the receiver array to separate more sources than the number of array sensors, provided that the sources have disjoint t-f signatures. With the use of one or more techniques proposed in this paper, improved performance of blind separation of nonstationary signals can be achieved.

Source term modelling parameters for Project-90

International Nuclear Information System (INIS)

Shaw, W.; Smith, G.; Worgan, K.; Hodgkinson, D.; Andersson, K.

1992-04-01

This document summarises the input parameters for the source term modelling within Project-90. In the first place, the parameters relate to the CALIBRE near-field code which was developed for the Swedish Nuclear Power Inspectorate's (SKI) Project-90 reference repository safety assessment exercise. An attempt has been made to give best estimate values and, where appropriate, a range which is related to variations around base cases. It should be noted that the data sets contain amendments to those considered by KBS-3. In particular, a completely new set of inventory data has been incorporated. The information given here does not constitute a complete set of parameter values for all parts of the CALIBRE code. Rather, it gives the key parameter values which are used in the constituent models within CALIBRE and the associated studies. For example, the inventory data acts as an input to the calculation of the oxidant production rates, which influence the generation of a redox front. The same data is also an initial value data set for the radionuclide migration component of CALIBRE. Similarly, the geometrical parameters of the near-field are common to both sub-models. The principal common parameters are gathered here for ease of reference and avoidance of unnecessary duplication and transcription errors. (au)

Geometric discretization of the multidimensional Dirac delta distribution - Application to the Poisson equation with singular source terms

Science.gov (United States)

Egan, Raphael; Gibou, Frédéric

2017-10-01

We present a discretization method for the multidimensional Dirac distribution. We show its applicability in the context of integration problems, and for discretizing Dirac-distributed source terms in Poisson equations with constant or variable diffusion coefficients. The discretization is cell-based and can thus be applied in a straightforward fashion to Quadtree/Octree grids. The method produces second-order accurate results for integration. Superlinear convergence is observed when it is used to model Dirac-distributed source terms in Poisson equations: the observed order of convergence is 2 or slightly smaller. The method is consistent with the discretization of Dirac delta distribution for codimension one surfaces presented in [1,2]. We present Quadtree/Octree construction procedures to preserve convergence and present various numerical examples, including multi-scale problems that are intractable with uniform grids.

Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

Science.gov (United States)

Evangeliou, Nikolaos; Hamburger, Thomas; Cozic, Anne; Balkanski, Yves; Stohl, Andreas

2017-07-01

This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30-50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km) than previously assumed (≈ 2.2 km) in order to better match both concentration

Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

Directory of Open Access Journals (Sweden)

N. Evangeliou

2017-07-01

Full Text Available This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30–50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km than previously assumed (≈ 2.2 km in order

Accelerator based continuous neutron source.

CERN Document Server

Shapiro, S M; Ruggiero, A G

2003-01-01

Until the last decade, most neutron experiments have been performed at steady-state, reactor-based sources. Recently, however, pulsed spallation sources have been shown to be very useful in a wide range of neutron studies. A major review of neutron sources in the US was conducted by a committee chaired by Nobel laureate Prof. W. Kohn: ''Neutron Sources for America's Future-BESAC Panel on Neutron Sources 1/93''. This distinguished panel concluded that steady state and pulsed sources are complementary and that the nation has need for both to maintain a balanced neutron research program. The report recommended that both a new reactor and a spallation source be built. This complementarity is recognized worldwide. The conclusion of this report is that a new continuous neutron source is needed for the second decade of the 20 year plan to replace aging US research reactors and close the US neutron gap. it is based on spallation production of neutrons using a high power continuous superconducting linac to generate pr...

Advanced Reactor PSA Methodologies for System Reliability Analysis and Source Term Assessment

Energy Technology Data Exchange (ETDEWEB)

Grabaskas, D.; Brunett, A.; Passerini, S.; Grelle, A.; Bucknor, M.

2017-06-26

Beginning in 2015, a project was initiated to update and modernize the probabilistic safety assessment (PSA) of the GE-Hitachi PRISM sodium fast reactor. This project is a collaboration between GE-Hitachi and Argonne National Laboratory (Argonne), and funded in part by the U.S. Department of Energy. Specifically, the role of Argonne is to assess the reliability of passive safety systems, complete a mechanistic source term calculation, and provide component reliability estimates. The assessment of passive system reliability focused on the performance of the Reactor Vessel Auxiliary Cooling System (RVACS) and the inherent reactivity feedback mechanisms of the metal fuel core. The mechanistic source term assessment attempted to provide a sequence specific source term evaluation to quantify offsite consequences. Lastly, the reliability assessment focused on components specific to the sodium fast reactor, including electromagnetic pumps, intermediate heat exchangers, the steam generator, and sodium valves and piping.

Alternate source term models for Yucca Mountain performance assessment based on natural analog data and secondary mineral solubility

International Nuclear Information System (INIS)

Murphy, W.M.; Codell, R.B.

1999-01-01

Performance assessment calculations for the proposed high level radioactive waste repository at Yucca Mountain, Nevada, were conducted using the Nuclear Regulatory Commission Total-System Performance Assessment (TPA 3.2) code to test conceptual models and parameter values for the source term based on data from the Pena Blanca, Mexico, natural analog site and based on a model for coprecipitation and solubility of secondary schoepite. In previous studies the value for the maximum constant oxidative alteration rate of uraninite at the Nopal I uranium body at Pena Blanca was estimated. Scaling this rate to the mass of uranium for the proposed Yucca Mountain repository yields an oxidative alteration rate of 22 kg/y, which was assumed to be an upper limit on the release rate from the proposed repository. A second model was developed assuming releases of radionuclides are based on the solubility of secondary schoepite as a function of temperature and solution chemistry. Releases of uranium are given by the product of uranium concentrations at equilibrium with schoepite and the flow of water through the waste packages. For both models, radionuclides other than uranium and those in the cladding and gap fraction were modeled to be released at a rate proportional to the uranium release rate, with additional elemental solubility limits applied. Performance assessment results using the Pena Blanca oxidation rate and schoepite solubility models for Yucca Mountain were compared to the TPA 3.2 base case model, in which release was based on laboratory studies of spent fuel dissolution, cladding and gap release, and solubility limits. Doses calculated using the release rate based on natural analog data and the schoepite solubility models were smaller than doses generated using the base case model. These results provide a degree of confidence in safety predictions using the base case model and an indication of how conservatism in the base case model may be reduced in future analyses

Alternate source term models for Yucca Mountain performance assessment based on natural analog data and secondary mineral solubility

Energy Technology Data Exchange (ETDEWEB)

Murphy, W.M.; Codell, R.B.

1999-07-01

Performance assessment calculations for the proposed high level radioactive waste repository at Yucca Mountain, Nevada, were conducted using the Nuclear Regulatory Commission Total-System Performance Assessment (TPA 3.2) code to test conceptual models and parameter values for the source term based on data from the Pena Blanca, Mexico, natural analog site and based on a model for coprecipitation and solubility of secondary schoepite. In previous studies the value for the maximum constant oxidative alteration rate of uraninite at the Nopal I uranium body at Pena Blanca was estimated. Scaling this rate to the mass of uranium for the proposed Yucca Mountain repository yields an oxidative alteration rate of 22 kg/y, which was assumed to be an upper limit on the release rate from the proposed repository. A second model was developed assuming releases of radionuclides are based on the solubility of secondary schoepite as a function of temperature and solution chemistry. Releases of uranium are given by the product of uranium concentrations at equilibrium with schoepite and the flow of water through the waste packages. For both models, radionuclides other than uranium and those in the cladding and gap fraction were modeled to be released at a rate proportional to the uranium release rate, with additional elemental solubility limits applied. Performance assessment results using the Pena Blanca oxidation rate and schoepite solubility models for Yucca Mountain were compared to the TPA 3.2 base case model, in which release was based on laboratory studies of spent fuel dissolution, cladding and gap release, and solubility limits. Doses calculated using the release rate based on natural analog data and the schoepite solubility models were smaller than doses generated using the base case model. These results provide a degree of confidence in safety predictions using the base case model and an indication of how conservatism in the base case model may be reduced in future analyses.

ITER safety task NID-5a: ITER tritium environmental source terms - safety analysis basis

International Nuclear Information System (INIS)

Natalizio, A.; Kalyanam, K.M.

1994-09-01

The Canadian Fusion Fuels Technology Project's (CFFTP) is part of the contribution to ITER task NID-5a, Initial Tritium Source Term. This safety analysis basis constitutes the first part of the work for establishing tritium source terms and is intended to solicit comments and obtain agreement. The analysis objective is to provide an early estimate of tritium environmental source terms for the events to be analyzed. Events that would result in the loss of tritium are: a Loss of Coolant Accident (LOCA), a vacuum vessel boundary breach. a torus exhaust line failure, a fuelling machine process boundary failure, a fuel processing system process boundary failure, a water detritiation system process boundary failure and an isotope separation system process boundary failure. 9 figs

Realistic minimum accident source terms - Evaluation, application, and risk acceptance

International Nuclear Information System (INIS)

Angelo, P. L.

2009-01-01

The evaluation, application, and risk acceptance for realistic minimum accident source terms can represent a complex and arduous undertaking. This effort poses a very high impact to design, construction cost, operations and maintenance, and integrated safety over the expected facility lifetime. At the 2005 Nuclear Criticality Safety Division (NCSD) Meeting in Knoxville Tenn., two papers were presented mat summarized the Y-12 effort that reduced the number of criticality accident alarm system (CAAS) detectors originally designed for the new Highly Enriched Uranium Materials Facility (HEUMF) from 258 to an eventual as-built number of 60. Part of that effort relied on determining a realistic minimum accident source term specific to the facility. Since that time, the rationale for an alternate minimum accident has been strengthened by an evaluation process that incorporates realism. A recent update to the HEUMF CAAS technical basis highlights the concepts presented here. (authors)

New Source Term Model for the RESRAD-OFFSITE Code Version 3

Energy Technology Data Exchange (ETDEWEB)

Yu, Charley [Argonne National Lab. (ANL), Argonne, IL (United States); Gnanapragasam, Emmanuel [Argonne National Lab. (ANL), Argonne, IL (United States); Cheng, Jing-Jy [Argonne National Lab. (ANL), Argonne, IL (United States); Kamboj, Sunita [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Shih-Yew [Argonne National Lab. (ANL), Argonne, IL (United States)

2013-06-01

This report documents the new source term model developed and implemented in Version 3 of the RESRAD-OFFSITE code. This new source term model includes: (1) "first order release with transport" option, in which the release of the radionuclide is proportional to the inventory in the primary contamination and the user-specified leach rate is the proportionality constant, (2) "equilibrium desorption release" option, in which the user specifies the distribution coefficient which quantifies the partitioning of the radionuclide between the solid and aqueous phases, and (3) "uniform release" option, in which the radionuclides are released from a constant fraction of the initially contaminated material during each time interval and the user specifies the duration over which the radionuclides are released.

Source-term development for a contaminant plume for use by multimedia risk assessment models

International Nuclear Information System (INIS)

Whelan, Gene; McDonald, John P.; Taira, Randal Y.; Gnanapragasam, Emmanuel K.; Yu, Charley; Lew, Christine S.; Mills, William B.

1999-01-01

Multimedia modelers from the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE) are collaborating to conduct a comprehensive and quantitative benchmarking analysis of four intermedia models: DOE's Multimedia Environmental Pollutant Assessment System (MEPAS), EPA's MMSOILS, EPA's PRESTO, and DOE's RESidual RADioactivity (RESRAD). These models represent typical analytically, semi-analytically, and empirically based tools that are utilized in human risk and endangerment assessments for use at installations containing radioactive and/or hazardous contaminants. Although the benchmarking exercise traditionally emphasizes the application and comparison of these models, the establishment of a Conceptual Site Model (CSM) should be viewed with equal importance. This paper reviews an approach for developing a CSM of an existing, real-world, Sr-90 plume at DOE's Hanford installation in Richland, Washington, for use in a multimedia-based benchmarking exercise bet ween MEPAS, MMSOILS, PRESTO, and RESRAD. In an unconventional move for analytically based modeling, the benchmarking exercise will begin with the plume as the source of contamination. The source and release mechanism are developed and described within the context of performing a preliminary risk assessment utilizing these analytical models. By beginning with the plume as the source term, this paper reviews a typical process and procedure an analyst would follow in developing a CSM for use in a preliminary assessment using this class of analytical tool

New source terms and the implications for emergency planning requirements at nuclear power plants in the United State

International Nuclear Information System (INIS)

Kaiser, G.D.; Cheok, M.C.

1987-01-01

This paper begins with a brief review of current approaches to source term driven changes to NRC emergency planning requirements and addresses significant differences between them. Approaches by IDCOR and EPRI, industry submittals to NRC and alternative risk-based evaluations have been considered. Important issues are discussed, such as the role of Protective Action Guides in determining the radius of the emergency planning zone (EPZ). The significance of current trends towards the prediction of longer warning times and longer durations of release in new source terms is assessed. These trends may help to relax the current notification time requirements. Finally, the implications of apparent support in the regulations for a threshold in warning time beyond which ad hoc protective measures are adequate is discussed

A novel integrated approach for the hazardous radioactive dust source terms estimation in future nuclear fusion power plants.

Science.gov (United States)

Poggi, L A; Malizia, A; Ciparisse, J F; Gaudio, P

2016-10-01

An open issue still under investigation by several international entities working on the safety and security field for the foreseen nuclear fusion reactors is the estimation of source terms that are a hazard for the operators and public, and for the machine itself in terms of efficiency and integrity in case of severe accident scenarios. Source term estimation is a crucial key safety issue to be addressed in the future reactors safety assessments, and the estimates available at the time are not sufficiently satisfactory. The lack of neutronic data along with the insufficiently accurate methodologies used until now, calls for an integrated methodology for source term estimation that can provide predictions with an adequate accuracy. This work proposes a complete methodology to estimate dust source terms starting from a broad information gathering. The wide number of parameters that can influence dust source term production is reduced with statistical tools using a combination of screening, sensitivity analysis, and uncertainty analysis. Finally, a preliminary and simplified methodology for dust source term production prediction for future devices is presented.

Dose assessments for Greifswald and Cadarache with updated source terms from ITER NSSR-2

International Nuclear Information System (INIS)

Raskob, W.; Hasemann, I.

1998-08-01

The International Thermonuclear Experimental Reactor ITER is in its late engineering phase. One of the most important safety aspects - in particular for achieving public acceptance - is to assure that the releases of harzardous material are minimal during normal operation and for accidental events, even if very unlikely. To this purpose probabilistic dose assessments for accidental atmospheric releases of various ITER source terms which contain tritium and/or activation products were performed for the sites of Greifswald, Germany, and Cadarache, France. In addition, routine releases into the atmosphere and hydrosphere have been evaluated. No country specific rules were applied and the input parameters were adapted as far as possible to those used within former studies to achieve a better comparability with site independent dose assessments performed in the frame of ITER. The calculations were based on source terms which, for the first time, contain a combination of tritium and activation products. This allowed a better judgment of the contribution to the total dose of the individual fusion relevant materials. The results were compared to site independent dose limits defined in the frame of ITER. Annual doses from routine releases (CAT-I) are below 0.1 μSv for the aquatic scenarios and are close to 1 μSv for the atmospheric source terms. Source terms for two different categories of accidental releases, representing 'extremely unlikely events' (CAT-IV) and 'hypothetical sequences' (CAT-V), were investigated. In none of these cases, the release scenarios of category CAT-IV exceed the ITER limits. In addition, relevant characteristic quantities of the early dose distribution from the hypothetical scenarios of type CAT-V are still below 50 mSv or 100 mSv, values which are commonly used as lower reference values for evacuation in many potential home countries of ITER. These site specific assessments confirmed that the proposed release limits and thus the derived dose

Source term evaluation model for high-level radioactive waste repository with decay chain build-up.

Science.gov (United States)

Chopra, Manish; Sunny, Faby; Oza, R B

2016-09-18

A source term model based on two-component leach flux concept is developed for a high-level radioactive waste repository. The long-lived radionuclides associated with high-level waste may give rise to the build-up of activity because of radioactive decay chains. The ingrowths of progeny are incorporated in the model using Bateman decay chain build-up equations. The model is applied to different radionuclides present in the high-level radioactive waste, which form a part of decay chains (4n to 4n + 3 series), and the activity of the parent and daughter radionuclides leaching out of the waste matrix is estimated. Two cases are considered: one when only parent is present initially in the waste and another where daughters are also initially present in the waste matrix. The incorporation of in situ production of daughter radionuclides in the source is important to carry out realistic estimates. It is shown that the inclusion of decay chain build-up is essential to avoid underestimation of the radiological impact assessment of the repository. The model can be a useful tool for evaluating the source term of the radionuclide transport models used for the radiological impact assessment of high-level radioactive waste repositories.

Chernobyl source term, atmospheric dispersion, and dose estimation

International Nuclear Information System (INIS)

Gudiksen, P.H.; Harvey, T.F.; Lange, R.

1988-02-01

The Chernobyl source term available for long-range transport was estimated by integration of radiological measurements with atmospheric dispersion modeling, and by reactor core radionuclide inventory estimation in conjunction with WASH-1400 release fractions associated with specific chemical groups. These analyses indicated that essentially all of the noble gases, 80% of the radioiodines, 40% of the radiocesium, 10% of the tellurium, and about 1% or less of the more refractory elements were released. Atmospheric dispersion modeling of the radioactive cloud over the Northern Hemisphere revealed that the cloud became segmented during the first day, with the lower section heading toward Scandinavia and the uppper part heading in a southeasterly direction with subsequent transport across Asia to Japan, the North Pacific, and the west coast of North America. The inhalation doses due to direct cloud exposure were estimated to exceed 10 mGy near the Chernobyl area, to range between 0.1 and 0.001 mGy within most of Europe, and to be generally less than 0.00001 mGy within the US. The Chernobyl source term was several orders of magnitude greater than those associated with the Windscale and TMI reactor accidents, while the 137 Cs from the Chernobyl event is about 6% of that released by the US and USSR atmospheric nuclear weapon tests. 9 refs., 3 figs., 6 tabs

Source term identification in atmospheric modelling via sparse optimization

Science.gov (United States)

Adam, Lukas; Branda, Martin; Hamburger, Thomas

2015-04-01

Inverse modelling plays an important role in identifying the amount of harmful substances released into atmosphere during major incidents such as power plant accidents or volcano eruptions. Another possible application of inverse modelling lies in the monitoring the CO2 emission limits where only observations at certain places are available and the task is to estimate the total releases at given locations. This gives rise to minimizing the discrepancy between the observations and the model predictions. There are two standard ways of solving such problems. In the first one, this discrepancy is regularized by adding additional terms. Such terms may include Tikhonov regularization, distance from a priori information or a smoothing term. The resulting, usually quadratic, problem is then solved via standard optimization solvers. The second approach assumes that the error term has a (normal) distribution and makes use of Bayesian modelling to identify the source term. Instead of following the above-mentioned approaches, we utilize techniques from the field of compressive sensing. Such techniques look for a sparsest solution (solution with the smallest number of nonzeros) of a linear system, where a maximal allowed error term may be added to this system. Even though this field is a developed one with many possible solution techniques, most of them do not consider even the simplest constraints which are naturally present in atmospheric modelling. One of such examples is the nonnegativity of release amounts. We believe that the concept of a sparse solution is natural in both problems of identification of the source location and of the time process of the source release. In the first case, it is usually assumed that there are only few release points and the task is to find them. In the second case, the time window is usually much longer than the duration of the actual release. In both cases, the optimal solution should contain a large amount of zeros, giving rise to the

Source term calculations - Ringhals 2 PWR. Interim report

Energy Technology Data Exchange (ETDEWEB)

Johansson, Lise-Lotte

1998-03-01

This project was performed within the fifth and final phase of sub-project RAK-2.1 of the Nordic Co-operative Reactor Safety Program, NKS. RAK-2.1 has also included studies of reflooding of degraded core, recriticality and late phase melt progression. Earlier source term calculations for Swedish nuclear power plants are based on the integral code MAAP. A need was recognised to compare these calculations with calculations done with mechanistic codes. In the present work SCDAP/RELAP5 and CONTAIN were used. Only limited results could be obtained within the frame of RAK-2.1, since many problems were encountered using the SCDAP/RELAP5 code. The main obstacle was the extremely long execution times of the MOD3.1 version, but also some dubious fission product calculations. However, some interesting results were obtained for the studied sequence, a total loss of AC power. The report describes the modelling approach for SCDAP/RELAP5 and CONTAIN, and discusses results for the transient including the event of a surge line creep rupture. The study will probably be completed later, providing that an improved SCDAP/RELAP5 code version becomes available 8 refs, 16 figs, 5 tabs

Fission product source terms and engineered safety features

International Nuclear Information System (INIS)

Malinauskas, A.P.

1984-01-01

The author states that new, technically defensible, methodologies to establish realistic source term values for nuclear reactor accidents will soon be available. Although these methodologies will undoubtedly find widespread use in the development of accident response procedures, the author states that it is less clear that the industry is preparing to employ the newer results to develop a more rational approach to strategies for the mitigation of fission product releases. Questions concerning the performance of existing engineered safety systems are reviewed

Use of source term code package in the ELEBRA MX-850 system

International Nuclear Information System (INIS)

Guimaraes, A.C.F.; Goes, A.G.A.

1988-12-01

The implantation of source term code package in the ELEBRA-MX850 system is presented. The source term is formed when radioactive materials generated in nuclear fuel leakage toward containment and the external environment to reactor containment. The implantated version in the ELEBRA system are composed of five codes: MARCH 3, TRAPMELT 3, THCCA, VANESA and NAVA. The original example case was used. The example consists of a small loca accident in a PWR type reactor. A sensitivity study for the TRAPMELT 3 code was carried out, modifying the 'TIME STEP' to estimate the processing time of CPU for executing the original example case. (M.C.K.) [pt

Development of Reference Source Terms for EU-APR1400

Energy Technology Data Exchange (ETDEWEB)

Kim, ByungIl; Lee, Chonghui; Lee, Dongsu; Ko, Heejin; Kang, Sangho [KEPCO Engineering and Construction Co. Inc., Yongin (Korea, Republic of)

2014-05-15

These source terms are developed for the typical U. S. NPP and do not reflect the design characteristics of EU-APR1400 (1,400 MWe PWR) which will be applied for the EUR certification in European countries. The process of developing the RST for EU-APR1400 is to undergo a similar process that NUREG-1465 had gone through when it came out with its proposed source terms. The purpose of this study is to develop the EU-APR1400 design-specific RST complied with the EUR. The Large LOCA is the reference equence used in the NUREG-1465 evaluation, whereas the EUAPR1400 risk-significant sequences are dominated by small LOCA and non-LOCA sequences. Moreover, when considering the EU-APR1400 has many design features to mitigate the consequences of severe accident phenomena, it is not surprising that the aspects of both release fractions and durations are distinctly different from NUREG-1465. This RST will be continuously updated to reflect to the design features of EU-APR1400, and then, be used as the reference for design purposes such as criteria satisfaction of radioactivity releases, equipment survivability, control room habitability for severe accident, and so on.

Semi-implicit and fully implicit shock-capturing methods for hyperbolic conservation laws with stiff source terms

International Nuclear Information System (INIS)

Yee, H.C.; Shinn, J.L.

1986-12-01

Some numerical aspects of finite-difference algorithms for nonlinear multidimensional hyperbolic conservation laws with stiff nonhomogenous (source) terms are discussed. If the stiffness is entirely dominated by the source term, a semi-implicit shock-capturing method is proposed provided that the Jacobian of the source terms possesses certain properties. The proposed semi-implicit method can be viewed as a variant of the Bussing and Murman point-implicit scheme with a more appropriate numerical dissipation for the computation of strong shock waves. However, if the stiffness is not solely dominated by the source terms, a fully implicit method would be a better choice. The situation is complicated by problems that are higher than one dimension, and the presence of stiff source terms further complicates the solution procedures for alternating direction implicit (ADI) methods. Several alternatives are discussed. The primary motivation for constructing these schemes was to address thermally and chemically nonequilibrium flows in the hypersonic regime. Due to the unique structure of the eigenvalues and eigenvectors for fluid flows of this type, the computation can be simplified, thus providing a more efficient solution procedure than one might have anticipated

Semi-implicit and fully implicit shock-capturing methods for hyperbolic conservation laws with stiff source terms

International Nuclear Information System (INIS)

Yee, H.C.; Shinn, J.L.

1987-01-01

Some numerical aspects of finite-difference algorithms for nonlinear multidimensional hyperbolic conservation laws with stiff nonhomogeneous (source) terms are discussed. If the stiffness is entirely dominated by the source term, a semi-implicit shock-capturing method is proposed provided that the Jacobian of the source terms possesses certain properties. The proposed semi-implicit method can be viewed as a variant of the Bussing and Murman point-implicit scheme with a more appropriate numerical dissipation for the computation of strong shock waves. However, if the stiffness is not solely dominated by the source terms, a fully implicit method would be a better choice. The situation is complicated by problems that are higher than one dimension, and the presence of stiff source terms further complicates the solution procedures for alternating direction implicit (ADI) methods. Several alternatives are discussed. The primary motivation for constructing these schemes was to address thermally and chemically nonequilibrium flows in the hypersonic regime. Due to the unique structure of the eigenvalues and eigenvectors for fluid flows of this type, the computation can be simplified, thus providing a more efficient solution procedure than one might have anticipated. 46 references

An appreciation of the events, models and data used for LMFBR radiological source term estimations

International Nuclear Information System (INIS)

Keir, D.; Clough, P.N.

1989-01-01

In this report, the events, models and data currently available for analysis of accident source terms in liquid metal cooled fast neutron reactors are reviewed. The types of hypothetical accidents considered are the low probability, more extreme types of severe accident, involving significant degradation of the core and which may lead to the release of radionuclides. The base case reactor design considered is a commercial scale sodium pool reactor of the CDFR type. The feasibility of an integrated calculational approach to radionuclide transport and speciation (such as is used for LWR accident analysis) is explored. It is concluded that there is no fundamental obstacle, in terms of scientific data or understanding of the phenomena involved, to such an approach. However this must be regarded as a long-term goal because of the large amount of effort still required to advance development to a stage comparable with LWR studies. Particular aspects of LMFBR severe accident phenomenology which require attention are the behaviour of radionuclides during core disruptive accident bubble formation and evolution, and during the less rapid sequences of core melt under sodium. The basic requirement for improved thermal hydraulic modelling of core, coolant and structural materials, in these and other scenarios, is highlighted as fundamental to the accuracy and realism of source term estimations. The coupling of such modelling to that of radionuclide behaviour is seen as the key to future development in this area

Improving long-term operation of power sources in off-grid hybrid systems based on renewable energy, hydrogen and battery

Science.gov (United States)

García, Pablo; Torreglosa, Juan P.; Fernández, Luis M.; Jurado, Francisco

2014-11-01

This paper presents two novel hourly energy supervisory controls (ESC) for improving long-term operation of off-grid hybrid systems (HS) integrating renewable energy sources (wind turbine and photovoltaic solar panels), hydrogen system (fuel cell, hydrogen tank and electrolyzer) and battery. The first ESC tries to improve the power supplied by the HS and the power stored in the battery and/or in the hydrogen tank, whereas the second one tries to minimize the number of needed elements (batteries, fuel cells and electrolyzers) throughout the expected life of the HS (25 years). Moreover, in both ESC, the battery state-of-charge (SOC) and the hydrogen tank level are controlled and maintained between optimum operating margins. Finally, a comparative study between the controls is carried out by models of the commercially available components used in the HS under study in this work. These ESC are also compared with a third ESC, already published by the authors, and based on reducing the utilization costs of the energy storage devices. The comparative study proves the right performance of the ESC and their differences.

Source terms for airborne radioactivity arising from uranium mill wastes

International Nuclear Information System (INIS)

O'Riordan, M.C.; Downing, A.L.

1978-01-01

One of the problems in assessing the radiological impact of uranium milling is to determine the rates of release to the air of material from the various sources of radioactivity. Such source terms are required for modelling the transport of radioactive material in the atmosphere. Activity arises from various point and area sources in the mill itself and from the mill tailings. The state of the tailings changes in time from slurry to solid. A layer of water may be maintained over the solids during the life of the mine, and the tailings may be covered with inert material on abandonment. Releases may be both gaseous and particulate. This paper indicates ways in which radon emanation and the suspension of long-lived particulate activity might be quantified, and areas requiring further exploration are identified

9Be(d,n)10B-based neutron sources for BNCT

International Nuclear Information System (INIS)

Capoulat, M.E.; Herrera, M.S.; Minsky, D.M.; González, S.J.; Kreiner, A.J.

2014-01-01

In the frame of accelerator-based BNCT, the 9 Be(d,n) 10 B reaction was investigated as a possible source of epithermal neutrons. In order to determine the configuration in terms of bombarding energy, target thickness and Beam Shaping Assembly (BSA) design that results in the best possible beam quality, a systematic optimization study was carried out. From this study, the optimal configuration resulted in tumor doses ≥40 Gy-Eq, with a maximum value of 51 Gy-Eq at a depth of about 2.7 cm, in a 60 min treatment. The optimal configuration was considered for the treatment planning assessment of a real Glioblastoma Multiforme case. From this, the resulted dose performances were comparable to those obtained with an optimized 7 Li(p,n)-based neutron source, under identical conditions and subjected to the same clinical protocol. - Highlights: • Study of the 9 Be(d,n) 10 B reaction as a source of epithermal neutrons for BNCT. • Evaluation of the optimal configuration of target thickness, deuteron energy and BSA design. • Computational dose assessment for brain tumor treatments using the MCNP code. • Treatment planning assessment of a particular clinical Glioblastoma Multiforme case. • Dose performances were comparable to those obtained with an optimized 7 Li(p,n)-based source

Unsplit schemes for hyperbolic conservation laws with source terms in one space dimension

International Nuclear Information System (INIS)

Papalexandris, M.V.; Leonard, A.; Dimotakis, P.E.

1997-01-01

The present work is concerned with an application of the theory of characteristics to conservation laws with source terms in one space dimension, such as the Euler equations for reacting flows. Space-time paths are introduced on which the flow/chemistry equations decouple to a characteristic set of ODE's for the corresponding homogeneous laws, thus allowing the introduction of functions analogous to the Riemann invariants in classical theory. The geometry of these paths depends on the spatial gradients of the solution. This particular decomposition can be used in the design of efficient unsplit algorithms for the numerical integration of the equations. As a first step, these ideas are implemented for the case of a scalar conservation law with a nonlinear source term. The resulting algorithm belongs to the class of MUSCL-type, shock-capturing schemes. Its accuracy and robustness are checked through a series of tests. The stiffness of the source term is also studied. Then, the algorithm is generalized for a system of hyperbolic equations, namely the Euler equations for reacting flows. A numerical study of unstable detonations is performed. 57 refs

Open Source GIS based integrated watershed management

Science.gov (United States)

Byrne, J. M.; Lindsay, J.; Berg, A. A.

2013-12-01

Optimal land and water management to address future and current resource stresses and allocation challenges requires the development of state-of-the-art geomatics and hydrological modelling tools. Future hydrological modelling tools should be of high resolution, process based with real-time capability to assess changing resource issues critical to short, medium and long-term enviromental management. The objective here is to merge two renowned, well published resource modeling programs to create an source toolbox for integrated land and water management applications. This work will facilitate a much increased efficiency in land and water resource security, management and planning. Following an 'open-source' philosophy, the tools will be computer platform independent with source code freely available, maximizing knowledge transfer and the global value of the proposed research. The envisioned set of water resource management tools will be housed within 'Whitebox Geospatial Analysis Tools'. Whitebox, is an open-source geographical information system (GIS) developed by Dr. John Lindsay at the University of Guelph. The emphasis of the Whitebox project has been to develop a user-friendly interface for advanced spatial analysis in environmental applications. The plugin architecture of the software is ideal for the tight-integration of spatially distributed models and spatial analysis algorithms such as those contained within the GENESYS suite. Open-source development extends knowledge and technology transfer to a broad range of end-users and builds Canadian capability to address complex resource management problems with better tools and expertise for managers in Canada and around the world. GENESYS (Generate Earth Systems Science input) is an innovative, efficient, high-resolution hydro- and agro-meteorological model for complex terrain watersheds developed under the direction of Dr. James Byrne. GENESYS is an outstanding research and applications tool to address

Source term for the bounding assessment of the Canadian nuclear fuel waste disposal concept

International Nuclear Information System (INIS)

Flavelle, P.

1996-02-01

This is the second in a series to derive the bounds of the post-closure hazard of the Canadian nuclear fuel waste disposal concept, based on the premise that it is unnecessary to predict accurately the real hazard if the bounding hazard can be shown to be acceptable. In this report a reference used (Bruce A fuel, 865 GJ/kgU average burnup) is used to derive the source term for contaminant releases from the emplacement canisters. This requires development of a container failure function which defines the age of the fuel when the canister is perforated and flooded. The source term is expressed as the time-dependent fractional release rate from the used fuel or as the time-dependent contaminant concentrations in the canister porewater. It is derived as the superposition of an instant release, comprising the upper bound of the gap and grain boundary inventory in the used fuel, and the long-term dissolution of the used fuel matrix. Several dissolution models (stoichiometric dissolution/preferential leaching) under different conditions (matrix solubility limited/ unlimited; oxidizing/ reducing solubility limits; groundwater flow/ no flow) are evaluated and the one resulting in the highest release rate/ highest porewater concentration is adopted as the bounding case. Comparisons between the models are made on the basis of the potential ingestion hazard of the canister porewater, to account for differences in the hazard of different radionuclides. (author) 20 refs., 4 tabs., 9 figs

Challenges in defining a radiologic and hydrologic source term for underground nuclear test centers, Nevada Test Site, Nye County, Nevada

International Nuclear Information System (INIS)

Smith, D.K.

1995-06-01

The compilation of a radionuclide inventory for long-lived radioactive contaminants residual from nuclear testing provides a partial measure of the radiologic source term at the Nevada Test Site. The radiologic source term also includes potentially mobile short-lived radionuclides excluded from the inventory. The radiologic source term for tritium is known with accuracy and is equivalent to the hydrologic source term within the saturated zone. Definition of the total hydrologic source term for fission and activation products that have high activities for decades following underground testing involves knowledge and assumptions which are presently unavailable. Systematic investigation of the behavior of fission products, activation products and actinides under saturated or Partially saturated conditions is imperative to define a representative total hydrologic source term. This is particularly important given the heterogeneous distribution of radionuclides within testing centers. Data quality objectives which emphasize a combination of measurements and credible estimates of the hydrologic source term are a priority for near-field investigations at the Nevada Test Site

Least-squares finite-element method for shallow-water equations with source terms

Institute of Scientific and Technical Information of China (English)

Shin-Jye Liang; Tai-Wen Hsu

2009-01-01

Numerical solution of shallow-water equations (SWE) has been a challenging task because of its nonlinear hyperbolic nature, admitting discontinuous solution, and the need to satisfy the C-property. The presence of source terms in momentum equations, such as the bottom slope and friction of bed, compounds the difficulties further. In this paper, a least-squares finite-element method for the space discretization and θ-method for the time integration is developed for the 2D non-conservative SWE including the source terms. Advantages of the method include: the source terms can be approximated easily with interpolation functions, no upwind scheme is needed, as well as the resulting system equations is symmetric and positive-definite, therefore, can be solved efficiently with the conjugate gradient method. The method is applied to steady and unsteady flows, subcritical and transcritical flow over a bump, 1D and 2D circular dam-break, wave past a circular cylinder, as well as wave past a hump. Computed results show good C-property, conservation property and compare well with exact solutions and other numerical results for flows with weak and mild gradient changes, but lead to inaccurate predictions for flows with strong gradient changes and discontinuities.

Atucha-I source terms for sequences initiated by transients

International Nuclear Information System (INIS)

Baron, J.; Bastianelli, B.

1997-01-01

The present work is part of an expected source terms study in the Atucha I nuclear power plant during severe accidents. From the accident sequences with a significant probability to produce core damage, those initiated by operational transients have been identified as the most relevant. These sequences have some common characteristics, in the sense that all of them resume in the opening of the primary system safety valves, and leave this path open for the coolant loss. In the case these sequences continue as severe accidents, the same path will be used for the release of the radionuclides, from the core, through the primary system and to the containment. Later in the severe accident sequence, the failure of the pressure vessel will occur, and the corium will fall inside the reactor cavity, interacting with the concrete. During these processes, more radioactive products will be released inside the containment. In the present work the severe accident simulation initiated by a blackout is performed, from the point of view of the phenomenology of the behavior of the radioactive products, as they are transported in the piping, during the core-concrete interactions, and inside the containment buildings until it failure. The final result is the source term into the atmosphere. (author) [es

Regulatory Technology Development Plan Sodium Fast Reactor. Mechanistic Source Term Development

Energy Technology Data Exchange (ETDEWEB)

Grabaskas, David S. [Argonne National Lab. (ANL), Argonne, IL (United States); Brunett, Acacia Joann [Argonne National Lab. (ANL), Argonne, IL (United States); Bucknor, Matthew D. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, James J. [Argonne National Lab. (ANL), Argonne, IL (United States); Sofu, Tanju [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-02-28

Construction and operation of a nuclear power installation in the U.S. requires licensing by the U.S. Nuclear Regulatory Commission (NRC). A vital part of this licensing process and integrated safety assessment entails the analysis of a source term (or source terms) that represents the release of radionuclides during normal operation and accident sequences. Historically, nuclear plant source term analyses have utilized deterministic, bounding assessments of the radionuclides released to the environment. Significant advancements in technical capabilities and the knowledge state have enabled the development of more realistic analyses such that a mechanistic source term (MST) assessment is now expected to be a requirement of advanced reactor licensing. This report focuses on the state of development of an MST for a sodium fast reactor (SFR), with the intent of aiding in the process of MST definition by qualitatively identifying and characterizing the major sources and transport processes of radionuclides. Due to common design characteristics among current U.S. SFR vendor designs, a metal-fuel, pool-type SFR has been selected as the reference design for this work, with all phenomenological discussions geared toward this specific reactor configuration. This works also aims to identify the key gaps and uncertainties in the current knowledge state that must be addressed for SFR MST development. It is anticipated that this knowledge state assessment can enable the coordination of technology and analysis tool development discussions such that any knowledge gaps may be addressed. Sources of radionuclides considered in this report include releases originating both in-vessel and ex-vessel, including in-core fuel, primary sodium and cover gas cleanup systems, and spent fuel movement and handling. Transport phenomena affecting various release groups are identified and qualitatively discussed, including fuel pin and primary coolant retention, and behavior in the cover gas and

Long-term dust aerosol production from natural sources in Iceland.

Science.gov (United States)

Dagsson-Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur

2017-02-01

Iceland is a volcanic island in the North Atlantic Ocean with maritime climate. In spite of moist climate, large areas are with limited vegetation cover where >40% of Iceland is classified with considerable to very severe erosion and 21% of Iceland is volcanic sandy deserts. Not only do natural emissions from these sources influenced by strong winds affect regional air quality in Iceland ("Reykjavik haze"), but dust particles are transported over the Atlantic ocean and Arctic Ocean >1000 km at times. The aim of this paper is to place Icelandic dust production area into international perspective, present long-term frequency of dust storm events in northeast Iceland, and estimate dust aerosol concentrations during reported dust events. Meteorological observations with dust presence codes and related visibility were used to identify the frequency and the long-term changes in dust production in northeast Iceland. There were annually 16.4 days on average with reported dust observations on weather stations within the northeastern erosion area, indicating extreme dust plume activity and erosion within the northeastern deserts, even though the area is covered with snow during the major part of winter. During the 2000s the highest occurrence of dust events in six decades was reported. We have measured saltation and Aeolian transport during dust/volcanic ash storms in Iceland, which give some of the most intense wind erosion events ever measured. Icelandic dust affects the ecosystems over much of Iceland and causes regional haze. It is likely to affect the ecosystems of the oceans around Iceland, and it brings dust that lowers the albedo of the Icelandic glaciers, increasing melt-off due to global warming. The study indicates that Icelandic dust may contribute to the Arctic air pollution. Long-term records of meteorological dust observations from Northeast Iceland indicate the frequency of dust events from Icelandic deserts. The research involves a 60-year period and

The Chernobyl reactor accident source term: development of a consensus view

International Nuclear Information System (INIS)

Devell, L.; Guntay, S.; Powers, D.A.

1995-11-01

Ten years after the reactor accident at Chernobyl, a great deal more data is available concerning the events, phenomena, and processes that took place. The purpose of this document is to examine what is known about the radioactive materials released during the accident, a task that is substantially more difficult than it might first appear to be. The Chernobyl station, like other nuclear power plants, was not instrumented to characterize a disastrous accident. The accident was peculiar in the sense that radioactive materials were released, at least initially, in an exceptionally energetic plume and were transported far from the reactor site. Release of radioactivity from the plant continued for several days. Characterization of the contamination caused by the releases of radioactivity has had a much lower priority than remediation of the contamination. Consequently, an assessment of the Chernobyl accident source term must rely to a significant extent on inferential evidence. The assessment presented here begins with an examination of the core inventories of radioactive materials. In subsequent sections of the report, the magnitude and timing of the releases of radioactivity are described. Then, the composition, chemical forms, and physical forms of the releases are discussed. A number of more recent publications and results from scientists in Russia and elsewhere have significantly improved the understanding of the Chernobyl source term. Because of the special features of the reactor design and the peculiarities of the Chernobyl accident, the source term for the Chernobyl accident is of limited applicability to the safety analysis of other types of reactors

Source-term characterisation and solid speciation of plutonium at the Semipalatinsk NTS, Kazakhstan.

Science.gov (United States)

Nápoles, H Jiménez; León Vintró, L; Mitchell, P I; Omarova, A; Burkitbayev, M; Priest, N D; Artemyev, O; Lukashenko, S

2004-01-01

New data on the concentrations of key fission/activation products and transuranium nuclides in samples of soil and water from the Semipalatinsk Nuclear Test Site are presented and interpreted. Sampling was carried out at Ground Zero, Lake Balapan, the Tel'kem craters and reference locations within the test site boundary well removed from localised sources. Radionuclide ratios have been used to characterise the source term(s) at each of these sites. The geochemical partitioning of plutonium has also been examined and it is shown that the bulk of the plutonium contamination at most of the sites examined is in a highly refractory, non-labile form.

Source-term characterisation and solid speciation of plutonium at the Semipalatinsk NTS, Kazakhstan

Energy Technology Data Exchange (ETDEWEB)

Napoles, H.J.H. Jimenez; Leon Vintro, L. E-mail: luis.leon@ucd.ie; Mitchell, P.I.; Omarova, A.; Burkitbayev, M.; Priest, N.D.; Artemyev, O.; Lukashenko, S

2004-09-01

New data on the concentrations of key fission/activation products and transuranium nuclides in samples of soil and water from the Semipalatinsk Nuclear Test Site are presented and interpreted. Sampling was carried out at Ground Zero, Lake Balapan, the Tel'kem craters and reference locations within the test site boundary well removed from localised sources. Radionuclide ratios have been used to characterise the source term(s) at each of these sites. The geochemical partitioning of plutonium has also been examined and it is shown that the bulk of the plutonium contamination at most of the sites examined is in a highly refractory, non-labile form.

Fission product source term research at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Malinauskas, A.P.

1985-01-01

The purpose of this work is to describe some of the research being performed at ORNL in support of the effort to describe, as realistically as possible, fission product source terms for nuclear reactor accidents. In order to make this presentation manageable, only those studies directly concerned with fission product behavior, as opposed to thermal hydraulics, accident sequence progression, etc., will be discussed

ERP correlates of source memory: unitized source information increases familiarity-based retrieval.

Science.gov (United States)

Diana, Rachel A; Van den Boom, Wijnand; Yonelinas, Andrew P; Ranganath, Charan

2011-01-07

Source memory tests typically require subjects to make decisions about the context in which an item was encoded and are thought to depend on recollection of details from the study episode. Although it is generally believed that familiarity does not contribute to source memory, recent behavioral studies have suggested that familiarity may also support source recognition when item and source information are integrated, or "unitized," during study (Diana, Yonelinas, and Ranganath, 2008). However, an alternative explanation of these behavioral findings is that unitization affects the manner in which recollection contributes to performance, rather than increasing familiarity-based source memory. To discriminate between these possibilities, we conducted an event-related potential (ERP) study testing the hypothesis that unitization increases the contribution of familiarity to source recognition. Participants studied associations between words and background colors using tasks that either encouraged or discouraged unitization. ERPs were recorded during a source memory test for background color. The results revealed two distinct neural correlates of source recognition: a frontally distributed positivity that was associated with familiarity-based source memory in the high-unitization condition only and a parietally distributed positivity that was associated with recollection-based source memory in both the high- and low-unitization conditions. The ERP and behavioral findings provide converging evidence for the idea that familiarity can contribute to source recognition, particularly when source information is encoded as an item detail. Copyright © 2010 Elsevier B.V. All rights reserved.

Proposal for implementation of alternative source term in the nuclear power plant of Laguna Verde

International Nuclear Information System (INIS)

Bazan L, A.; Lopez L, M.; Vargas A, A.; Cardenas J, J. B.

2009-10-01

In 2010 the nuclear power plant of Laguna Verde will implement the extended power upbeat in both units of the plant. Agree with methodology of NEDC-33004P-A, (constant pressure power up rate), and the source term of core, for accidents evaluations, were increased in proportion to the ratio of power level. This means that for the case of a design basis accident of loss of coolant an increase of power of 15% originated an increase of 15% in dose to main control room. Using the method of NEDC-33004P-A to extended power upbeat conditions was determined that the dose value to main control room is very near to regulatory limit established by SRP 6.4. By the above and in order to recover the margin, the nuclear power plant of Laguna Verde will calculate an alternative source term following the criteria established in RG 1.183 (alternative radiological source term for evaluating DBA at nuclear power reactor). This approach also have a more realistic dose value using the criterion of 10-CFR-50.67, in addition is predicted to get the benefit of additional operational flexibilities. This paper present the proposal of implementing the alternative source term in Laguna Verde. (Author)

Review of the accident source terms for aluminide fuel: Application to the BR2 reactor

International Nuclear Information System (INIS)

Joppen, F.

2005-01-01

A major safety review of the BR2, a material test reactor, is to be conducted for the year 2006. One of the subjects selected for the safety review is the definition of source terms for emergency planning and in particular the development of accident scenarios. For nuclear power plants the behaviour of fuel under accident conditions is a well studied object. In case of non-power reactors this basic knowledge is rather scarce. The usefulness of information from power plant fuels is limited due to the differences in fuel type, power level and thermohydraulical conditions. First investigation indicates that using data from power plant fuel leads to an overestimation of the source terms. Further research on this subject could be very useful for the research reactor community, in order to define more realistic source terms and to improve the emergency preparedness. (author)

The long-term relationships among China's energy consumption sources and adjustments to its renewable energy policy

International Nuclear Information System (INIS)

Zou Gaolu

2012-01-01

To reduce its consumption of coal and oil in its primary energy consumption, China promotes the development of renewable energy resources. I have analysed the long-term relationship among China's primary energy consumption sources. Changes in coal consumption lead those in the consumption of other energy sources in the long term. Coal and oil fuels substitute for each other equally. The long-term elasticities of China's coal consumption relative to its hydroelectricity consumption were greater than one and nearly equal during the two sample periods. Therefore, increased hydroelectricity consumption did not imply a reduction in coal consumption. China holds abundant hydroelectricity, wind and, solar energy potential. China must prevent an excessive escalation of its economy and resultant energy demand to realise a meaningful substitution of coal with hydroelectricity. Moreover, China must develop and use wind and solar energy sources. Natural gas can be a good substitute for coal, given its moderate price growth and affordable price levels. - Highlights: ► Coal consumption changes lead those of other energy sources in the long term. ► Coal and oil fuels substitute for each other equally. ► Increased hydroelectricity consumption has not meant lower coal consumption. ► Wind, solar and natural gas are China's promising energy sources.

Development of in-vessel source term analysis code, tracer

International Nuclear Information System (INIS)

Miyagi, K.; Miyahara, S.

1996-01-01

Analyses of radionuclide transport in fuel failure accidents (generally referred to source terms) are considered to be important especially in the severe accident evaluation. The TRACER code has been developed to realistically predict the time dependent behavior of FPs and aerosols within the primary cooling system for wide range of fuel failure events. This paper presents the model description, results of validation study, the recent model advancement status of the code, and results of check out calculations under reactor conditions. (author)

Prospects of renewable energy sources in India: Prioritization of alternative sources in terms of Energy Index

International Nuclear Information System (INIS)

Jha, Shibani K.; Puppala, Harish

2017-01-01

The growing energy demand in progressing civilization governs the exploitation of various renewable sources over the conventional sources. Wind, Solar, Hydro, Biomass, and waste & Bagasse are the various available renewable sources in India. A reliable nonconventional geothermal source is also available in India but it is restricted to direct heat applications. This study archives the status of renewable alternatives in India. The techno economic factors and environmental aspects associated with each of these alternatives are discussed. This study focusses on prioritizing the renewable sources based on a parameter introduced as Energy Index. This index is evaluated using cumulative scores obtained for each of the alternatives. The cumulative score is obtained by evaluating each alternative over a range of eleven environmental and techno economic criteria following Fuzzy Analytical Hierarchy Process. The eleven criteria's considered in the study are Carbon dioxide emissions (CO 2 ), Sulphur dioxide emissions (SO 2 ), Nitrogen oxide emissions (NO x ), Land requirement, Current energy cost, Potential future energy cost, Turnkey investment, Capacity factor, Energy efficiency, Design period and Water consumption. It is concluded from the study that the geothermal source is the most preferable alternative with highest Energy Index. Hydro, Wind, Biomass and Solar sources are subsequently preferred alternatives. - Highlights: • FAH process is used to obtain cumulative score for each renewable alternative. • Cumulative score is normalized by highest score of ideal source. • Energy Index shows how best a renewable alternative is. • Priority order is obtained for alternatives based on Energy Index. • Geothermal is most preferable source followed by Hydro, Wind, Biomass and Solar.

Quantification of source-term profiles from near-field geochemical models

International Nuclear Information System (INIS)

McKinley, I.G.

1985-01-01

A geochemical model of the near-field is described which quantitatively treats the processes of engineered barrier degradation, buffering of aqueous chemistry by solid phases, nuclide solubilization and transport through the near-field and release to the far-field. The radionuclide source-terms derived from this model are compared with those from a simpler model used for repository safety analysis. 10 refs., 2 figs., 2 tabs

Methodology for and uses of a radiological source term assessment for potential impacts to stormwater and groundwater

International Nuclear Information System (INIS)

Teare, A.; Hansen, K.; DeWilde, J.; Yu, L.; Killey, D.

2001-01-01

A Radiological Source Term Assessment (RSTA) was conducted by Ontario Power Generation Inc. (OPG) at the Pickering Nuclear Generating Station (PNGS). Tritium had been identified in the groundwater at several locations under the station, and OPG initiated the RSTA as part of its ongoing efforts to improve operations and to identify potential sources of radionuclide impact to groundwater and stormwater at the station. The RSTA provides a systematic approach to collecting information and assessing environmental risk for radioactive contaminants based on a ranking system developed for the purpose. This paper provides an overview of the RSTA focusing on the investigative approach and how it was applied. This approach can find application at other generating stations. (author)

Derivation of the source term, dose results and associated radiological consequences for the Greek Research Reactor – 1

Energy Technology Data Exchange (ETDEWEB)

Pappas, Charalampos, E-mail: chpappas@ipta.demokritos.gr; Ikonomopoulos, Andreas; Sfetsos, Athanasios; Andronopoulos, Spyros; Varvayanni, Melpomeni; Catsaros, Nicolas

2014-07-01

Highlights: • Source term derivation of postulated accident sequences in a research reactor. • Various containment ventilation scenarios considered for source term calculations. • Source term parametric analysis performed in case of lack of ventilation. • JRODOS employed for dose calculations under eighteen modeled scenarios. • Estimation of radiological consequences during typical and adverse weather scenarios. - Abstract: The estimated source term, dose results and radiological consequences of selected accident sequences in the Greek Research Reactor – 1 are presented and discussed. A systematic approach has been adopted to perform the necessary calculations in accordance with the latest computational developments and IAEA recommendations. Loss-of-coolant, reactivity insertion and fuel channel blockage accident sequences have been selected to derive the associated source terms under three distinct containment ventilation scenarios. Core damage has been conservatively assessed for each accident sequence while the ventilation has been assumed to function within the efficiency limits defined at the Safety Analysis Report. In case of lack of ventilation a parametric analysis is also performed to examine the dependency of the source term on the containment leakage rate. A typical as well as an adverse meteorological scenario have been defined in the JRODOS computational platform in order to predict the effective, lung and thyroid doses within a region defined by a 15 km radius downwind from the reactor building. The radiological consequences of the eighteen scenarios associated with the accident sequences are presented and discussed.

Source term and activation calculations for the new TR-FLEX cyclotron for medical applications at HZDR

Energy Technology Data Exchange (ETDEWEB)

Konheiser, Joerg [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactor Safety; Ferrari, A. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Radiation Physics; Magin, A. [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany); Naumann, B. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Dept. of Radiation Protection and Safety; Mueller, S.E.

2017-06-01

The neutron source terms for a proton beam hitting an {sup 18}O-enriched water target were calculated with the radiation transport programs MCNP6 and FLUKA and were compared to source terms for exclusive {sup 18}O(p,n){sup 18}F production. To validate the radiation fields obtained in the simulations, an experimental program has been started using activation samples originally used in reactor dosimetry.

Nanomaterial-based x-ray sources

Science.gov (United States)

Cole, Matthew T.; Parmee, R. J.; Milne, William I.

2016-02-01

Following the recent global excitement and investment in the emerging, and rapidly growing, classes of one and two-dimensional nanomaterials, we here present a perspective on one of the viable applications of such materials: field electron emission based x-ray sources. These devices, which have a notable history in medicine, security, industry and research, to date have almost exclusively incorporated thermionic electron sources. Since the middle of the last century, field emission based cathodes were demonstrated, but it is only recently that they have become practicable. We outline some of the technological achievements of the past two decades, and describe a number of the seminal contributions. We explore the foremost market hurdles hindering their roll-out and broader industrial adoption and summarise the recent progress in miniaturised, pulsed and multi-source devices.

Use of source term uncoupled in radionuclide migration equations

International Nuclear Information System (INIS)

Silveira, Claudia Siqueira da; Lima, Zelmo Rodrigues de; Alvim, Antonio Carlos Marques

2008-01-01

Final repositories of high-level radioactive waste have been considered in deep, low permeability and stable geological formations. A common problem found is the migration modeling of radionuclides in a fractured rock. In this work, the physical system adopted consists of the rock matrix containing a single planar fracture situated in water saturated porous rock. The partial differential equations that describe the radionuclide transport were discretized using finite differences techniques, of which the following methods were adopted: Explicit Euler, Implicit Euler and Crank-Nicholson. For each one of these methods, the advective term was discretized with the following numerical schemes: backward differences, centered differences and forward differences. We make a comparison to determine which temporal and space discretization has the best result in relation to a reference solution. The obtained results show that the Explicit Euler Method with forward discretization in the advective term has a good accuracy. Next, with the objective of improving the answer of the Implicit Euler and Crank-Nicholson Methods it was accomplished a source term uncouplement, the diffusive flux. The obtained results were considered satisfactory by comparison with previous studies. (author)

Short-term X-ray variability of the globular cluster source 4U 1820 - 30 (NGC 6624)

Science.gov (United States)

Stella, L.; Kahn, S. M.; Grindlay, J. E.

1984-01-01

Analytical techniques for improved identification of the temporal and spectral variability properties of globular cluster and galactic bulge X-ray sources are described in terms of their application to a large set of observations of the source 4U 1820 - 30 in the globular cluster NGC 6624. The autocorrelation function, cross-correlations, time skewness function, erratic periodicities, and pulse trains are examined. The results are discussed in terms of current models with particular emphasis on recent accretion disk models. It is concluded that the analyzed observations provide the first evidence for shot-noise variability in a globular cluster X-ray source.

A source term estimation method for a nuclear accident using atmospheric dispersion models

DEFF Research Database (Denmark)

Kim, Minsik; Ohba, Ryohji; Oura, Masamichi

2015-01-01

The objective of this study is to develop an operational source term estimation (STE) method applicable for a nuclear accident like the incident that occurred at the Fukushima Dai-ichi nuclear power station in 2011. The new STE method presented here is based on data from atmospheric dispersion...... models and short-range observational data around the nuclear power plants.The accuracy of this method is validated with data from a wind tunnel study that involved a tracer gas release from a scaled model experiment at Tokai Daini nuclear power station in Japan. We then use the methodology developed...... and validated through the effort described in this manuscript to estimate the release rate of radioactive material from the Fukushima Dai-ichi nuclear power station....

Evaluation of applicability of alternative source terms to operating nuclear power plants in Korea

International Nuclear Information System (INIS)

Lim, S. N.; Park, Y. S.; Nam, K. M.; Song, D. B.; Bae, Y. J.; Lee, Y. J.; Jung, C. Y.

2002-01-01

In 1995 and 2000, NRC issued NUREG-1465 and Regulatory Guide 1.183 with respect to Alternative Source Terms(AST) replacing the existing source terms of TID-14844 and Regulatory Guide 1.4, 1.25, and 1.77 for radiological Design Basis Accidents(DBA) analysis. In 1990, ICRP published ICRP Pub. 60 which represents new recommendations on dose criteria and concepts. In Korea, alternative source terms were used for evaluation of effective doses for design basis accidents of Advanced Power Reactor(APR1400) using the computer program developed by an overseas company. Recently, DBADOSE, new computer program for DBA analysis incorporating AST and effective dose concept was developed by KHNP and KOPEC, and reanalysis applying AST to operating nuclear power plants, Kori units 3 and 4 in Korea using DBADOSE has been performed. As the results of this analysis, it was concluded that some conservative variables or operation procedures of operating plants could be mitigated or simplified by virtue of increased safety margin and consequently, economical and operational benefits ensue. In this paper, methodologies and results of Kori 3 and 4 DBA reanalysis and sensitivity analysis for mitigation of main design variables are introduced

Long term leaching of chlorinated solvents from source zones in low permeability settings with fractures

DEFF Research Database (Denmark)

Bjerg, Poul Løgstrup; Chambon, Julie Claire Claudia; Troldborg, Mads

2008-01-01

spreads to the low permeability matrix by diffusion. This results in a long term source of contamination due to back-diffusion. Leaching from such sources is further complicated by microbial degradation under anaerobic conditions to sequentially form the daughter products trichloroethylene, cis...

Accuracy of Dual-Energy Virtual Monochromatic CT Numbers: Comparison between the Single-Source Projection-Based and Dual-Source Image-Based Methods.

Science.gov (United States)

Ueguchi, Takashi; Ogihara, Ryota; Yamada, Sachiko

2018-03-21

To investigate the accuracy of dual-energy virtual monochromatic computed tomography (CT) numbers obtained by two typical hardware and software implementations: the single-source projection-based method and the dual-source image-based method. A phantom with different tissue equivalent inserts was scanned with both single-source and dual-source scanners. A fast kVp-switching feature was used on the single-source scanner, whereas a tin filter was used on the dual-source scanner. Virtual monochromatic CT images of the phantom at energy levels of 60, 100, and 140 keV were obtained by both projection-based (on the single-source scanner) and image-based (on the dual-source scanner) methods. The accuracy of virtual monochromatic CT numbers for all inserts was assessed by comparing measured values to their corresponding true values. Linear regression analysis was performed to evaluate the dependency of measured CT numbers on tissue attenuation, method, and their interaction. Root mean square values of systematic error over all inserts at 60, 100, and 140 keV were approximately 53, 21, and 29 Hounsfield unit (HU) with the single-source projection-based method, and 46, 7, and 6 HU with the dual-source image-based method, respectively. Linear regression analysis revealed that the interaction between the attenuation and the method had a statistically significant effect on the measured CT numbers at 100 and 140 keV. There were attenuation-, method-, and energy level-dependent systematic errors in the measured virtual monochromatic CT numbers. CT number reproducibility was comparable between the two scanners, and CT numbers had better accuracy with the dual-source image-based method at 100 and 140 keV. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

X radiation sources based on accelerators

International Nuclear Information System (INIS)

Couprie, M.E.; Filhol, J.M.

2008-01-01

Light sources based on accelerators aim at producing very high brilliance coherent radiation, tunable from the infrared to X-ray range, with picosecond or femtosecond light pulses. The first synchrotron light sources were built around storage rings in which a large number of relativistic electrons produce 'synchrotron radiation' when their trajectory is subjected to a magnetic field, either in bending magnets or in specific insertion devices (undulators), made of an alternating series of magnets, allowing the number of curvatures to be increased and the radiation to be reinforced. These 'synchrotron radiation' storage rings are now used worldwide (there are more than thirty), and they simultaneously distribute their radiation to several tens of users around the storage ring. The most effective installations in term of brilliance are the so-called third generation synchrotron radiation light sources. The radiation produced presents pulse durations of the order of a few tens of ps, at a high rate (of the order of MHz); it is tunable over a large range, depending on the magnetic field and the electron beam energy and its polarisation is adjustable (in the V-UV-soft-X range). Generally, a very precise spectral selection is made by the users with a monochromator. The single pass linear accelerators can produce very short electron bunches (around 100 fs). The beam of very high electronic density is sent into successive undulator modules, reinforcing the radiation's longitudinal coherence, produced according to a Free Electron Laser (FEL) scheme by the interaction between the electron bunch and a light wave. The very high peak brilliance justifies their designation as fourth generation sources. The number of users is smaller because an electron pulse produces a radiation burst towards only one beamline. Energy Recovery Linacs (ERL) let the beam pass several times in the accelerator structures either to recover the energy or to accelerate the electrons during several turns

Accelerator-based pulsed cold neutron source

International Nuclear Information System (INIS)

Inoue, Kazuhiko; Iwasa, Hirokatsu; Kiyanagi, Yoshiaki

1979-01-01

An accelerator-based pulsed cold neutron source was constructed. The accelerator is a 35 MeV electron linear accelerator with 1 kW average beam power. The cold neutron beam intensity at a specimen is equivalent to that of a research reactor of 10 14 n/cm 2 .s thermal flux in the case of the quasi-elastic neutron scattering measurements. In spite of some limitations to the universal uses, it has been demonstrated by this facility that the modest capacity accelerator-based pulsed cold neutron source is a highly efficient cold neutron source with low capital investment. Design philosophy, construction details, performance and some operational experiences are described. (author)

Basic repository source term and data sheet report: Davis Canyon

International Nuclear Information System (INIS)

1988-01-01

This report is one of series describing studies undertaken in support of the US Department of Energy Civilian Radioactive Waste Management (CRWM) Program. This study contains the derivation of values for environmental source terms and resources consumed for a CRWM repository. Estimates include heavy construction equipment; support equipment; shaft-sinking equipment; transportation equipment; and consumption of fuel, water electricity, and natural gas. Data are presented for construction and operation at an assumed site in Davis Canyon, Utah. 6 tabs

Preliminary investigation of processes that affect source term identification

International Nuclear Information System (INIS)

Wickliff, D.S.; Solomon, D.K.; Farrow, N.D.

1991-09-01

Solid Waste Storage Area (SWSA) 5 is known to be a significant source of contaminants, especially tritium ( 3 H), to the White Oak Creek (WOC) watershed. For example, Solomon et al. (1991) estimated the total 3 H discharge in Melton Branch (most of which originates in SWSA 5) for the 1988 water year to be 1210 Ci. A critical issue for making decisions concerning remedial actions at SWSA 5 is knowing whether the annual contaminant discharge is increasing or decreasing. Because (1) the magnitude of the annual contaminant discharge is highly correlated to the amount of annual precipitation (Solomon et al., 1991) and (2) a significant lag may exist between the time of peak contaminant release from primary sources (i.e., waste trenches) and the time of peak discharge into streams, short-term stream monitoring by itself is not sufficient for predicting future contaminant discharges. In this study we use 3 H to examine the link between contaminant release from primary waste sources and contaminant discharge into streams. By understanding and quantifying subsurface transport processes, realistic predictions of future contaminant discharge, along with an evaluation of the effectiveness of remedial action alternatives, will be possible. The objectives of this study are (1) to characterize the subsurface movement of contaminants (primarily 3 H) with an emphasis on the effects of matrix diffusion; (2) to determine the relative strength of primary vs secondary sources; and (3) to establish a methodology capable of determining whether the 3 H discharge from SWSA 5 to streams is increasing or decreasing

Benchmarking the New RESRAD-OFFSITE Source Term Model with DUST-MS and GoldSim - 13377

Energy Technology Data Exchange (ETDEWEB)

Cheng, J.J.; Kamboj, S.; Gnanapragasam, E.; Yu, C. [Argonne National Laboratory, Argonne, IL 60439 (United States)

2013-07-01

RESRAD-OFFSITE is a computer code developed by Argonne National Laboratory under the sponsorship of U.S. Department of Energy (DOE) and U.S. Nuclear Regulatory Commission (NRC). It is designed on the basis of RESRAD (onsite) code, a computer code designated by DOE and NRC for evaluating soil-contaminated sites for compliance with human health protection requirements pertaining to license termination or environmental remediation. RESRAD-OFFSITE has enhanced capabilities of modeling radionuclide transport to offsite locations and calculating potential radiation exposure to offsite receptors. Recently, a new source term model was incorporated into RESRAD-OFFSITE to enhance its capability further. This new source term model allows simulation of radionuclide releases from different waste forms, in addition to the soil sources originally considered in RESRAD (onsite) and RESRAD-OFFSITE codes. With this new source term model, a variety of applications can be achieved by using RESRAD-OFFSITE, including but not limited to, assessing the performance of radioactive waste disposal facilities. This paper presents the comparison of radionuclide release rates calculated by the new source term model of RESRAD-OFFSITE versus those calculated by DUST-MS and GoldSim, respectively. The focus of comparison is on the release rates of radionuclides from the bottom of the contaminated zone that was assumed to contain radioactive source materials buried in soil. The transport of released contaminants outside of the primary contaminated zone is beyond the scope of this paper. Overall, the agreement between the RESRAD-OFFSITE results and the DUST-MS and GoldSim results is fairly good, with all three codes predicting identical or similar radionuclide release profiles over time. Numerical dispersion in the DUST-MS and GoldSim results was identified as potentially contributing to the disagreement in the release rates. In general, greater discrepancy in the release rates was found for short

Benchmarking the New RESRAD-OFFSITE Source Term Model with DUST-MS and GoldSim - 13377

International Nuclear Information System (INIS)

Cheng, J.J.; Kamboj, S.; Gnanapragasam, E.; Yu, C.

2013-01-01

RESRAD-OFFSITE is a computer code developed by Argonne National Laboratory under the sponsorship of U.S. Department of Energy (DOE) and U.S. Nuclear Regulatory Commission (NRC). It is designed on the basis of RESRAD (onsite) code, a computer code designated by DOE and NRC for evaluating soil-contaminated sites for compliance with human health protection requirements pertaining to license termination or environmental remediation. RESRAD-OFFSITE has enhanced capabilities of modeling radionuclide transport to offsite locations and calculating potential radiation exposure to offsite receptors. Recently, a new source term model was incorporated into RESRAD-OFFSITE to enhance its capability further. This new source term model allows simulation of radionuclide releases from different waste forms, in addition to the soil sources originally considered in RESRAD (onsite) and RESRAD-OFFSITE codes. With this new source term model, a variety of applications can be achieved by using RESRAD-OFFSITE, including but not limited to, assessing the performance of radioactive waste disposal facilities. This paper presents the comparison of radionuclide release rates calculated by the new source term model of RESRAD-OFFSITE versus those calculated by DUST-MS and GoldSim, respectively. The focus of comparison is on the release rates of radionuclides from the bottom of the contaminated zone that was assumed to contain radioactive source materials buried in soil. The transport of released contaminants outside of the primary contaminated zone is beyond the scope of this paper. Overall, the agreement between the RESRAD-OFFSITE results and the DUST-MS and GoldSim results is fairly good, with all three codes predicting identical or similar radionuclide release profiles over time. Numerical dispersion in the DUST-MS and GoldSim results was identified as potentially contributing to the disagreement in the release rates. In general, greater discrepancy in the release rates was found for short

An Open-Source Based ITS Platform

DEFF Research Database (Denmark)

Andersen, Ove; Krogh, Benjamin Bjerre; Torp, Kristian

2013-01-01

In this paper, a complete platform used to compute travel times from GPS data is described. Two approaches to computing travel time are proposed one based on points and one based on trips. Overall both approaches give reasonable results compared to existing manual estimated travel times. However......, the trip-based approach requires more GPS data and of a higher quality than the point-based approach. The platform has been completely implemented using open-source software. The main conclusion is that large quantity of GPS data can be managed, with a limited budget and that GPS data is a good source...... for estimating travel times, if enough data is available....

A Parameter Identification Method for Helicopter Noise Source Identification and Physics-Based Semi-Empirical Modeling

Science.gov (United States)

Greenwood, Eric, II; Schmitz, Fredric H.

2010-01-01

A new physics-based parameter identification method for rotor harmonic noise sources is developed using an acoustic inverse simulation technique. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. This new method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor Blade-Vortex Interaction (BVI) noise, allowing accurate estimates of BVI noise to be made for operating conditions based on a small number of measurements taken at different operating conditions.

Effect of Fuel Structure Materials on Radiation Source Term in Reactor Core Meltdown

International Nuclear Information System (INIS)

Jeong, Hae Sun; Ha, Kwang Soon

2014-01-01

The fission product (Radiation Source) releases from the reactor core into the containment is obligatorily evaluated to guarantee the safety of Nuclear Power Plant (NPP) under the hypothetical accident involving a core meltdown. The initial core inventory is used as a starting point of all radiological consequences and effects on the subsequent results of accident assessment. Hence, a proper evaluation for the inventory can be regarded as one of the most important part over the entire procedure of accident analysis. The inventory of fission products is typically evaluated on the basis of the uranium material (e.g., UO2 and USi2) loaded in nuclear fuel assembly, except for the structure materials such as the end fittings, grids, and some kinds of springs. However, the structure materials are continually activated by the neutrons generated from the nuclear fission, and some nuclides of them (e.g., 14 C and 60 Co) can significantly influence on accident assessment. During the severe core accident, the structure components can be also melted with the melting points of temperature relatively lower than uranium material. A series of the calculation were performed by using ORIGEN-S module in SCALE 6.1 package code system. The total activity in each part of structure materials was specifically analyzed from these calculations. The fission product inventory is generally evaluated based on the uranium materials of fuel only, even though the structure components of the assembly are continually activated by the neutrons generated from the nuclear fission. In this study, the activation calculation of the fuel structure materials was performed for the initial source term assessment in the accident of reactor core meltdown. As a result, the lower end fitting and the upper plenum greatly contribute to the total activity except for the cladding material. The nuclides of 56 Mn, '5 1 Cr, 55 Fe, 58 Co, 54 Mn, and 60 Co are analyzed to mainly effect on the activity. This result

Source Term Characteristics Analysis for Structural Components in PWR spent fuel assembly

Energy Technology Data Exchange (ETDEWEB)

Kook, Dong Hak; Choi, Heui Joo; Cho, Dong Keun [KAERI, Daejeon (Korea, Republic of)

2010-12-15

Source terms of metal waste comprising a spent fuel assembly are relatively important when the spent fuel is pyroprocessed, because cesium, strontium, and transuranics are not a concern any more in the aspect of source term of permanent disposal. In this study, characteristics of radiation source terms for each structural component in spent fuel assembly was analyzed by using ORIGEN-S with a assumption that 10 metric tons of uranium is pyroprocessed. At first, mass and volume for each structural component of the fuel assembly were calculated in detail. Activation cross section library was generated by using KENO-VI/ORIGEN-S module for top-end piece and bottom-end piece, because those are located at outer core under different neutron spectrum compared to that of inner core. As a result, values of radioactivity, decay heat, and hazard index were reveled to be 1.32x1015 Bequerels, 238 Watts, 4.32x109 m3 water, respectively, at 10 years after discharge. Those values correspond to 0.6 %, 1.1 %, 0.1 %, respectively, compared to that of spent fuel. Inconel 718 grid plate was shown to be the most important component in the all aspects of radioactivity, decay heat, and hazard index although the mass occupies only 1 % of the total. It was also shown that if the Inconel 718 grid plate is managed separately, the radioactivity and hazard index of metal waste could be decreased to 25{approx}50 % and 35{approx}40 %, respectively. As a whole, decay heat of metal waste was shown to be negligible in the aspect of disposal system design, while the radioactivity and hazard index are important

Term Bases and Linguistic Linked Open Data

DEFF Research Database (Denmark)

for pursuing their work. The theme of this year’s TKE is ‘Term Bases and Linguistic Linked Open Data’. Mono- and multi-lingual term bases, which contain information about concepts (terms, definitions, examples of use, references, comments on equivalence etc.), have always made up valuable linguistic resources...

The Analytical Repository Source-Term (AREST) model: Description and documentation

International Nuclear Information System (INIS)

Liebetrau, A.M.; Apted, M.J.; Engel, D.W.; Altenhofen, M.K.; Strachan, D.M.; Reid, C.R.; Windisch, C.F.; Erikson, R.L.; Johnson, K.I.

1987-10-01

The geologic repository system consists of several components, one of which is the engineered barrier system. The engineered barrier system interfaces with natural barriers that constitute the setting of the repository. A model that simulates the releases from the engineered barrier system into the natural barriers of the geosphere, called a source-term model, is an important component of any model for assessing the overall performance of the geologic repository system. The Analytical Repository Source-Term (AREST) model being developed is one such model. This report describes the current state of development of the AREST model and the code in which the model is implemented. The AREST model consists of three component models and five process models that describe the post-emplacement environment of a waste package. All of these components are combined within a probabilistic framework. The component models are a waste package containment (WPC) model that simulates the corrosion and degradation processes which eventually result in waste package containment failure; a waste package release (WPR) model that calculates the rates of radionuclide release from the failed waste package; and an engineered system release (ESR) model that controls the flow of information among all AREST components and process models and combines release output from the WPR model with failure times from the WPC model to produce estimates of total release. 167 refs., 40 figs., 12 tabs

Analysis of the source term in the Chernobyl-4 accident

International Nuclear Information System (INIS)

Alonso, A.; Lopez Montero, J.V.; Pinedo Garrido, P.

1990-01-01

The report presents the analysis of the Chernobyl accident and of the phenomena with major influence on the source term, including the chemical effects of materials dumped over the reactor, carried out by the Chair of Nuclear Technology at Madrid University under a contract with the CEC. It also includes the comparison of the ratio (Cs-137/Cs-134) between measurements performed by Soviet authorities and countries belonging to the Community and OECD area. Chapter II contains a summary of both isotope measurements (Cs-134 and Cs-137), and their ratios, in samples of air, water, soil and agricultural and animal products collected by the Soviets in their report presented in Vienna (1986). Chapter III reports on the inventories of cesium isotopes in the core, while Chapter IV analyses the transient, especially the fuel temperature reached, as a way to deduce the mechanisms which took place in the cesium escape. The cesium source term is analyzed in Chapter V. Normal conditions have been considered, as well as the transient and the post-accidental period, including the effects of deposited materials. The conclusion of this study is that Chernobyl accidental sequence is specific of the RBMK type of reactors, and that in the Western world, basic research on fuel behaviour for reactivity transients has already been carried out

Room Volume Estimation Based on Ambiguity of Short-Term Interaural Phase Differences Using Humanoid Robot Head

Directory of Open Access Journals (Sweden)

Ryuichi Shimoyama

2016-07-01

Full Text Available Humans can recognize approximate room size using only binaural audition. However, sound reverberation is not negligible in most environments. The reverberation causes temporal fluctuations in the short-term interaural phase differences (IPDs of sound pressure. This study proposes a novel method for a binaural humanoid robot head to estimate room volume. The method is based on the statistical properties of the short-term IPDs of sound pressure. The humanoid robot turns its head toward a sound source, recognizes the sound source, and then estimates the ego-centric distance by its stereovision. By interpolating the relations between room volume, average standard deviation, and ego-centric distance experimentally obtained for various rooms in a prepared database, the room volume was estimated by the binaural audition of the robot from the average standard deviation of the short-term IPDs at the estimated distance.

Virtual Reality Based Accurate Radioactive Source Representation and Dosimetry for Training Applications

International Nuclear Information System (INIS)

Molto-Caracena, T.; Vendrell Vidal, E.; Goncalves, J.G.M.; Peerani, P.; )

2015-01-01

Virtual Reality (VR) technologies have much potential for training applications. Success relies on the capacity to provide a real-time immersive effect to a trainee. For a training application to be an effective/meaningful tool, 3D realistic scenarios are not enough. Indeed, it is paramount having sufficiently accurate models of the behaviour of the instruments to be used by a trainee. This will enable the required level of user's interactivity. Specifically, when dealing with simulation of radioactive sources, a VR model based application must compute the dose rate with equivalent accuracy and in about the same time as a real instrument. A conflicting requirement is the need to provide a smooth visual rendering enabling spatial interactivity and interaction. This paper presents a VR based prototype which accurately computes the dose rate of radioactive and nuclear sources that can be selected from a wide library. Dose measurements reflect local conditions, i.e., presence of (a) shielding materials with any shape and type and (b) sources with any shape and dimension. Due to a novel way of representing radiation sources, the system is fast enough to grant the necessary user interactivity. The paper discusses the application of this new method and its advantages in terms of time setting, cost and logistics. (author)

Short-term solar irradiation forecasting based on Dynamic Harmonic Regression

International Nuclear Information System (INIS)

Trapero, Juan R.; Kourentzes, Nikolaos; Martin, A.

2015-01-01

Solar power generation is a crucial research area for countries that have high dependency on fossil energy sources and is gaining prominence with the current shift to renewable sources of energy. In order to integrate the electricity generated by solar energy into the grid, solar irradiation must be reasonably well forecasted, where deviations of the forecasted value from the actual measured value involve significant costs. The present paper proposes a univariate Dynamic Harmonic Regression model set up in a State Space framework for short-term (1–24 h) solar irradiation forecasting. Time series hourly aggregated as the Global Horizontal Irradiation and the Direct Normal Irradiation will be used to illustrate the proposed approach. This method provides a fast automatic identification and estimation procedure based on the frequency domain. Furthermore, the recursive algorithms applied offer adaptive predictions. The good forecasting performance is illustrated with solar irradiance measurements collected from ground-based weather stations located in Spain. The results show that the Dynamic Harmonic Regression achieves the lowest relative Root Mean Squared Error; about 30% and 47% for the Global and Direct irradiation components, respectively, for a forecast horizon of 24 h ahead. - Highlights: • Solar irradiation forecasts at short-term are required to operate solar power plants. • This paper assesses the Dynamic Harmonic Regression to forecast solar irradiation. • Models are evaluated using hourly GHI and DNI data collected in Spain. • The results show that forecasting accuracy is improved by using the model proposed

Diagnostic and prognostic system for identification of accident scenarios and prediction of 'source term' in nuclear power plants under accident conditions

International Nuclear Information System (INIS)

Santhosh; Gera, B.; Kumar, Mithilesh

2014-01-01

Nuclear power plant experiences a number of transients during its operations. These transients may be due to equipment failure, malfunctioning of process support systems etc. In such a situation, the plant may result in an abnormal state which is undesired. In case of such an undesired plant condition, the operator has to carry out diagnostic and corrective actions. When an event occurs starting from the steady state operation, instruments' readings develop a time dependent pattern and these patterns are unique with respect to the type of the particular event. Therefore, by properly selecting the plant process parameters, the transients can be distinguished. In this connection, a computer based tool known as Diagnostic and Prognostic System has been developed for identification of large pipe break scenarios in 220 MWe Pressurised Heavy Water Reactors (PHWRs) and for prediction of expected 'Source Term' and consequence for a situation where Emergency Core Cooling System (ECCS) is not available or partially available. Diagnostic and Prognostic System is essentially a transient identification and expected source term forecasting system. The system is based on Artificial Neural Networks (ANNs) that continuously monitors the plant conditions and identifies a Loss Of Coolant Accident (LOCA) scenario quickly based on the reactor process parameter values. The system further identifies the availability of injection of ECCS and in case non-availability of ECCS, it can forecast expected 'Source Term'. The system is a support to plant operators as well as for emergency preparedness. The ANN is trained with a process parameter database pertaining to accident conditions and tested against blind exercises. In order to see the feasibility of implementing in the plant for real-time diagnosis, this system has been set up on a high speed computing facility and has been demonstrated successfully for LOCA scenarios. (author)

Fiber-based broadband black-light source

OpenAIRE

Sylvestre , Thibaut; Lee , Min Won; Ragueh , A. R.; Stiller , Birgit; Fanjoux , Gil; Barviau , B.; Mussot , A.; Kudlinski , A.

2012-01-01

International audience; Black-Light or Wood's lamp refers to sources that emit long-wavelength ultraviolet radiation (UV-A) from 315 nm and little visible light till 410 nm (blue). In this paper, we present a new fibre-based source of "black light", a source that emits broadband ultraviolet radiation but only small amounts of visible light and no infrared light. We made this source by pumping a specially designed silica photonic crystal fibre (PCF) with 355 nm light pulses from a Q-switched f...

Basic repository source term and data sheet report: Lavender Canyon

International Nuclear Information System (INIS)

1988-01-01

This report is one of a series describing studies undertaken in support of the US Department of Energy Civilian Radioactive Waste Management (CRWM) Program. This study contains the derivation of values for environmental source terms and resources consumed for a CRWM repository. Estimates include heavy construction equipment; support equipment; shaft-sinking equipment; transportation equipment; and consumption of fuel, water, electricity, and natural gas. Data are presented for construction and operation at an assumed site in Lavender Canyon, Utah. 3 refs; 6 tabs

Cardiac magnetic source imaging based on current multipole model

International Nuclear Information System (INIS)

Tang Fa-Kuan; Wang Qian; Hua Ning; Lu Hong; Tang Xue-Zheng; Ma Ping

2011-01-01

It is widely accepted that the heart current source can be reduced into a current multipole. By adopting three linear inverse methods, the cardiac magnetic imaging is achieved in this article based on the current multipole model expanded to the first order terms. This magnetic imaging is realized in a reconstruction plane in the centre of human heart, where the current dipole array is employed to represent realistic cardiac current distribution. The current multipole as testing source generates magnetic fields in the measuring plane, serving as inputs of cardiac magnetic inverse problem. In the heart-torso model constructed by boundary element method, the current multipole magnetic field distribution is compared with that in the homogeneous infinite space, and also with the single current dipole magnetic field distribution. Then the minimum-norm least-squares (MNLS) method, the optimal weighted pseudoinverse method (OWPIM), and the optimal constrained linear inverse method (OCLIM) are selected as the algorithms for inverse computation based on current multipole model innovatively, and the imaging effects of these three inverse methods are compared. Besides, two reconstructing parameters, residual and mean residual, are also discussed, and their trends under MNLS, OWPIM and OCLIM each as a function of SNR are obtained and compared. (general)

A New Wave Equation Based Source Location Method with Full-waveform Inversion

KAUST Repository

Wu, Zedong

2017-05-26

Locating the source of a passively recorded seismic event is still a challenging problem, especially when the velocity is unknown. Many imaging approaches to focus the image do not address the velocity issue and result in images plagued with illumination artifacts. We develop a waveform inversion approach with an additional penalty term in the objective function to reward the focusing of the source image. This penalty term is relaxed early to allow for data fitting, and avoid cycle skipping, using an extended source. At the later stages the focusing of the image dominates the inversion allowing for high resolution source and velocity inversion. We also compute the source location explicitly and numerical tests show that we obtain good estimates of the source locations with this approach.

Emergency preparedness source term development for the Office of Nuclear Material Safety and Safeguards-Licensed Facilities

International Nuclear Information System (INIS)

Sutter, S.L.; Mishima, J.; Ballinger, M.Y.; Lindsey, C.G.

1984-08-01

In order to establish requirements for emergency preparedness plans at facilities licensed by the Office of Nuclear Materials Safety and Safeguards, the Nuclear Regulatory Commission (NRC) needs to develop source terms (the amount of material made airborne) in accidents. These source terms are used to estimate the potential public doses from the events, which, in turn, will be used to judge whether emergency preparedness plans are needed for a particular type of facility. Pacific Northwest Laboratory is providing the NRC with source terms by developing several accident scenarios for eleven types of fuel cycle and by-product operations. Several scenarios are developed for each operation, leading to the identification of the maximum release considered for emergency preparedness planning (MREPP) scenario. The MREPP scenarios postulated were of three types: fire, tornado, and criticality. Fire was significant at oxide fuel fabrication, UF 6 production, radiopharmaceutical manufacturing, radiopharmacy, sealed source manufacturing, waste warehousing, and university research and development facilities. Tornadoes were MREPP events for uranium mills and plutonium contaminated facilities, and criticalities were significant at nonoxide fuel fabrication and nuclear research and development facilities. Techniques for adjusting the MREPP release to different facilities are also described

Environmental radiation safety: source term modification by soil aerosols. Interim report

International Nuclear Information System (INIS)

Moss, O.R.; Allen, M.D.; Rossignol, E.J.; Cannon, W.C.

1980-08-01

The goal of this project is to provide information useful in estimating hazards related to the use of a pure refractory oxide of 238 Pu as a power source in some of the space vehicles to be launched during the next few years. Although the sources are designed and built to withstand re-entry into the earth's atmosphere, and to impact with the earth's surface without releasing any plutonium, the possibility that such an event might produce aerosols composed of soil and 238 PuO 2 cannot be absolutely excluded. This report presents the results of our most recent efforts to measure the degree to which the plutonium aerosol source term might be modified in a terrestrial environment. The five experiments described represent our best effort to use the original experimental design to study the change in the size distribution and concentration of a 238 PuO 2 aerosol due to coagulation with an aerosol of clay or sandy loam soil

Standardization of iridium-192 coiled source in terms of air kerma output

Energy Technology Data Exchange (ETDEWEB)

Shanta, A; Unnikrishnan, K; Tripathi, U B; Kannan, A; Iyer, P S [Bhabha Atomic Research Centre, Bombay (India)

1996-08-01

ICRU (1985) recommended that the output of gamma ray brachytherapy sources should be specified in terms of reference air kerma rate, defined as the kerma rate to air in air at a reference distance of 1 meter, perpendicular to the long axis of the source, corrected for air attenuation and scattering. As these measurements are difficult to carry out in the routine clinical use, it is the common practice to calibrate the re-entrant ionization chamber with respect to open air measurements and use the re-entrant chamber for routine measurements. This paper reports on the measurements carried out to correlate the nominal activity and air kerma rate of {sup 192}Ir wire sources supplied by the Board of Radiation and Isotope Technology, Department of Atomic Energy. (author). 3 refs, 1 tab.

Standardization of iridium-192 coiled source in terms of air kerma output

International Nuclear Information System (INIS)

Shanta, A.; Unnikrishnan, K.; Tripathi, U.B.; Kannan, A.; Iyer, P.S.

1996-01-01

ICRU (1985) recommended that the output of gamma ray brachytherapy sources should be specified in terms of reference air kerma rate, defined as the kerma rate to air in air at a reference distance of 1 meter, perpendicular to the long axis of the source, corrected for air attenuation and scattering. As these measurements are difficult to carry out in the routine clinical use, it is the common practice to calibrate the re-entrant ionization chamber with respect to open air measurements and use the re-entrant chamber for routine measurements. This paper reports on the measurements carried out to correlate the nominal activity and air kerma rate of 192 Ir wire sources supplied by the Board of Radiation and Isotope Technology, Department of Atomic Energy. (author). 3 refs, 1 tab

Long-term program up to fiscal 1993 of electric power source development

International Nuclear Information System (INIS)

Kawakami, Shin-ichi

1984-01-01

The long-term, ten years, program up to fiscal 1993 of electric power source development, determined by the Government aims at stable power supply and the expansion of utilization of petroleum-substitute energy. The annual growth in the gross national product (GNP) during the ten years was taken as about 4 %. So, the total electric power demand in fiscal 1993 is scheduled to be 731,000 million kwh, about 34 % up from 547,000 million kwh in fiscal 1983. The structure of electric power sources at the end of fiscal 1993 will be hydraulic 19.7 %, thermal 58.3 %, and nuclear 21.9 %. The development of electric power sources to be initiated in fiscal 1984 is hydraulic 500 MW, thermal 2,000 MW, and nuclear 6,000 MW. (Mori, K.)

Modeling of Radiotherapy Linac Source Terms Using ARCHER Monte Carlo Code: Performance Comparison for GPU and MIC Parallel Computing Devices

Science.gov (United States)

Lin, Hui; Liu, Tianyu; Su, Lin; Bednarz, Bryan; Caracappa, Peter; Xu, X. George

2017-09-01

Monte Carlo (MC) simulation is well recognized as the most accurate method for radiation dose calculations. For radiotherapy applications, accurate modelling of the source term, i.e. the clinical linear accelerator is critical to the simulation. The purpose of this paper is to perform source modelling and examine the accuracy and performance of the models on Intel Many Integrated Core coprocessors (aka Xeon Phi) and Nvidia GPU using ARCHER and explore the potential optimization methods. Phase Space-based source modelling for has been implemented. Good agreements were found in a tomotherapy prostate patient case and a TrueBeam breast case. From the aspect of performance, the whole simulation for prostate plan and breast plan cost about 173s and 73s with 1% statistical error.

The Phebus Fission Product and Source Term International Programmes

International Nuclear Information System (INIS)

Clement, B.; Zeyen, R.

2005-01-01

The international Phebus FP programme, initiated in 1988 is one of the major research programmes on light water reactors severe accidents. After a short description of the facility and of the test matrix, the main outcomes and results of the first four integral tests are provided and analysed. Several results were unexpected and some are of importance for safety analyses, particularly concerning fuel degradation, cladding oxidation, chemical form of some fission products, especially iodine, effect of control rod materials on degradation and chemistry, iodine behaviour in the containment. Prediction capabilities of calculation tools have largely been improved as a result of this research effort. However, significant uncertainties remain for a number of phenomena, requiring detailed physical analysis and implementation of improved models in codes, sustained by a number of separate-effect experiments. This is the subject of the new Source Term programme for a better understanding of the phenomenology on important safety issues, in accordance with priorities defined in the EURSAFE project of the 5 th European framework programme aiming at reducing the uncertainties on Source Term analyses. It covers iodine chemistry, impact of boron carbide control rods degradation and oxidation, air ingress situations and fission product release from fuel. Regarding the interpretation of Phebus, an international co-operation has been established since over ten years, particularly helpful for the improvement and common understanding of severe accident phenomena. Few months ago, the Phebus community was happy to welcome representatives of a large number of organisations from the following new European countries: the Czech republic, Hungary, Lithuania, Slovakia, Slovenia and also from Bulgaria and Romania. (author)

Radioactivity source terms for underground engineering application

Energy Technology Data Exchange (ETDEWEB)

Tewes, H A [Lawrence Radiation Laboratory, Livermore, CA (United States)

1969-07-01

The constraints on nuclide production are usually very similar in any underground engineering application of nuclear explosives. However, in some applications the end product could be contaminated unless the proper nuclear device is used. This fact can be illustrated from two underground engineering experiments-Gasbuggy and Sloop. In the Gasbuggy experiment, appreciable tritium has been shown to be present in the gas currently being produced. However, in future gas stimulation applications (as distinct from experiments), a minimum production of tritium by the explosive is desirable since product contamination by this nuclide may place severe limitations on the use of the tritiated gas. In Sloop, where production of copper is the goal of the experiment, product contamination would not be caused by tritium but could result from other nuclides: Thus, gas stimulation could require the use of fission explosives while the lower cost per kiloton of thermonuclear explosives could make them attractive for ore-crushing applications. Because of this consideration, radionuclide production calculations must be made for both fission and for thermonuclear explosives in the underground environment. Such activation calculations materials of construction are performed in a manner similar to that described in another paper, but radionuclide production in the environment must be computed using both fission neutron and 14-MeV neutron sources in order to treat the 'source term' problem realistically. In making such computations, parameter studies including the effects of environmental temperature, neutron shielding, and rock types have been carried out. Results indicate the importance of carefully evaluating the radionuclide production for each individual underground engineering application. (author)

Radioactivity source terms for underground engineering application

International Nuclear Information System (INIS)

Tewes, H.A.

1969-01-01

The constraints on nuclide production are usually very similar in any underground engineering application of nuclear explosives. However, in some applications the end product could be contaminated unless the proper nuclear device is used. This fact can be illustrated from two underground engineering experiments-Gasbuggy and Sloop. In the Gasbuggy experiment, appreciable tritium has been shown to be present in the gas currently being produced. However, in future gas stimulation applications (as distinct from experiments), a minimum production of tritium by the explosive is desirable since product contamination by this nuclide may place severe limitations on the use of the tritiated gas. In Sloop, where production of copper is the goal of the experiment, product contamination would not be caused by tritium but could result from other nuclides: Thus, gas stimulation could require the use of fission explosives while the lower cost per kiloton of thermonuclear explosives could make them attractive for ore-crushing applications. Because of this consideration, radionuclide production calculations must be made for both fission and for thermonuclear explosives in the underground environment. Such activation calculations materials of construction are performed in a manner similar to that described in another paper, but radionuclide production in the environment must be computed using both fission neutron and 14-MeV neutron sources in order to treat the 'source term' problem realistically. In making such computations, parameter studies including the effects of environmental temperature, neutron shielding, and rock types have been carried out. Results indicate the importance of carefully evaluating the radionuclide production for each individual underground engineering application. (author)

Finite volume schemes with equilibrium type discretization of source terms for scalar conservation laws

International Nuclear Information System (INIS)

Botchorishvili, Ramaz; Pironneau, Olivier

2003-01-01

We develop here a new class of finite volume schemes on unstructured meshes for scalar conservation laws with stiff source terms. The schemes are of equilibrium type, hence with uniform bounds on approximate solutions, valid in cell entropy inequalities and exact for some equilibrium states. Convergence is investigated in the framework of kinetic schemes. Numerical tests show high computational efficiency and a significant advantage over standard cell centered discretization of source terms. Equilibrium type schemes produce accurate results even on test problems for which the standard approach fails. For some numerical tests they exhibit exponential type convergence rate. In two of our numerical tests an equilibrium type scheme with 441 nodes on a triangular mesh is more accurate than a standard scheme with 5000 2 grid points

Economical comparison of imported energy sources in terms of long-term production planning

International Nuclear Information System (INIS)

Gungor, Z.

1999-01-01

In this paper, the Turkish energy production sector is studied and power plants fueled by natural gas, imported coal and nuclear power are compared in terms of long-term (1996-2010) production economy. A net present value is used for comparing nuclear, coal and natural gas power plants. A scenario approach is utilized in establishing the effects of different factors, such as inflation rate, unit of investment costs, load factor change, discount rate and fuel price changes. Six different scenarios of interest are developed and discussed. The study ends with conclusions and recommendations based on a study of a reference scenario and alternative scenarios. (author)

Transparent mediation-based access to multiple yeast data sources using an ontology driven interface.

Science.gov (United States)

Briache, Abdelaali; Marrakchi, Kamar; Kerzazi, Amine; Navas-Delgado, Ismael; Rossi Hassani, Badr D; Lairini, Khalid; Aldana-Montes, José F

2012-01-25

Saccharomyces cerevisiae is recognized as a model system representing a simple eukaryote whose genome can be easily manipulated. Information solicited by scientists on its biological entities (Proteins, Genes, RNAs...) is scattered within several data sources like SGD, Yeastract, CYGD-MIPS, BioGrid, PhosphoGrid, etc. Because of the heterogeneity of these sources, querying them separately and then manually combining the returned results is a complex and time-consuming task for biologists most of whom are not bioinformatics expert. It also reduces and limits the use that can be made on the available data. To provide transparent and simultaneous access to yeast sources, we have developed YeastMed: an XML and mediator-based system. In this paper, we present our approach in developing this system which takes advantage of SB-KOM to perform the query transformation needed and a set of Data Services to reach the integrated data sources. The system is composed of a set of modules that depend heavily on XML and Semantic Web technologies. User queries are expressed in terms of a domain ontology through a simple form-based web interface. YeastMed is the first mediation-based system specific for integrating yeast data sources. It was conceived mainly to help biologists to find simultaneously relevant data from multiple data sources. It has a biologist-friendly interface easy to use. The system is available at http://www.khaos.uma.es/yeastmed/.

Long-term monitoring on environmental disasters using multi-source remote sensing technique

Science.gov (United States)

Kuo, Y. C.; Chen, C. F.

2017-12-01

Environmental disasters are extreme events within the earth's system that cause deaths and injuries to humans, as well as causing damages and losses of valuable assets, such as buildings, communication systems, farmlands, forest and etc. In disaster management, a large amount of multi-temporal spatial data is required. Multi-source remote sensing data with different spatial, spectral and temporal resolutions is widely applied on environmental disaster monitoring. With multi-source and multi-temporal high resolution images, we conduct rapid, systematic and seriate observations regarding to economic damages and environmental disasters on earth. It is based on three monitoring platforms: remote sensing, UAS (Unmanned Aircraft Systems) and ground investigation. The advantages of using UAS technology include great mobility and availability in real-time rapid and more flexible weather conditions. The system can produce long-term spatial distribution information from environmental disasters, obtaining high-resolution remote sensing data and field verification data in key monitoring areas. It also supports the prevention and control on ocean pollutions, illegally disposed wastes and pine pests in different scales. Meanwhile, digital photogrammetry can be applied on the camera inside and outside the position parameters to produce Digital Surface Model (DSM) data. The latest terrain environment information is simulated by using DSM data, and can be used as references in disaster recovery in the future.

Sensitivity analysis and benchmarking of the BLT low-level waste source term code

International Nuclear Information System (INIS)

Suen, C.J.; Sullivan, T.M.

1993-07-01

To evaluate the source term for low-level waste disposal, a comprehensive model had been developed and incorporated into a computer code, called BLT (Breach-Leach-Transport) Since the release of the original version, many new features and improvements had also been added to the Leach model of the code. This report consists of two different studies based on the new version of the BLT code: (1) a series of verification/sensitivity tests; and (2) benchmarking of the BLT code using field data. Based on the results of the verification/sensitivity tests, the authors concluded that the new version represents a significant improvement and it is capable of providing more realistic simulations of the leaching process. Benchmarking work was carried out to provide a reasonable level of confidence in the model predictions. In this study, the experimentally measured release curves for nitrate, technetium-99 and tritium from the saltstone lysimeters operated by Savannah River Laboratory were used. The model results are observed to be in general agreement with the experimental data, within the acceptable limits of uncertainty

On the application of subcell resolution to conservation laws with stiff source terms

International Nuclear Information System (INIS)

Chang, S.

1989-11-01

LeVeque and Yee recently investigated a one-dimensional scalar conservation law with stiff source terms modeling the reacting flow problems and discovered that for the very stiff case most of the current finite difference methods developed for non-reacting flows would produce wrong solutions when there is a propagating discontinuity. A numerical scheme, essentially nonoscillatory/subcell resolution - characteristic direction (ENO/SRCD), is proposed for solving conservation laws with stiff source terms. This scheme is a modification of Harten's ENO scheme with subcell resolution, ENO/SR. The locations of the discontinuities and the characteristic directions are essential in the design. Strang's time-splitting method is used and time evolutions are done by advancing along the characteristics. Numerical experiment using this scheme shows excellent results on the model problem of LeVeque and Yee. Comparisons of the results of ENO, ENO/SR, and ENO/SRCD are also presented

A functional magnetic resonance imaging investigation of short-term source and item memory for negative pictures.

Science.gov (United States)

Mitchell, Karen J; Mather, Mara; Johnson, Marcia K; Raye, Carol L; Greene, Erich J

2006-10-02

We investigated the hypothesis that arousal recruits attention to item information, thereby disrupting working memory processes that help bind items to context. Using functional magnetic resonance imaging, we compared brain activity when participants remembered negative or neutral picture-location conjunctions (source memory) versus pictures only. Behaviorally, negative trials showed disruption of short-term source, but not picture, memory; long-term picture recognition memory was better for negative than for neutral pictures. Activity in areas involved in working memory and feature integration (precentral gyrus and its intersect with superior temporal gyrus) was attenuated on negative compared with neutral source trials relative to picture-only trials. Visual processing areas (middle occipital and lingual gyri) showed greater activity for negative than for neutral trials, especially on picture-only trials.

Asymptotically and exactly energy balanced augmented flux-ADER schemes with application to hyperbolic conservation laws with geometric source terms

Science.gov (United States)

Navas-Montilla, A.; Murillo, J.

2016-07-01

In this work, an arbitrary order HLL-type numerical scheme is constructed using the flux-ADER methodology. The proposed scheme is based on an augmented Derivative Riemann solver that was used for the first time in Navas-Montilla and Murillo (2015) [1]. Such solver, hereafter referred to as Flux-Source (FS) solver, was conceived as a high order extension of the augmented Roe solver and led to the generation of a novel numerical scheme called AR-ADER scheme. Here, we provide a general definition of the FS solver independently of the Riemann solver used in it. Moreover, a simplified version of the solver, referred to as Linearized-Flux-Source (LFS) solver, is presented. This novel version of the FS solver allows to compute the solution without requiring reconstruction of derivatives of the fluxes, nevertheless some drawbacks are evidenced. In contrast to other previously defined Derivative Riemann solvers, the proposed FS and LFS solvers take into account the presence of the source term in the resolution of the Derivative Riemann Problem (DRP), which is of particular interest when dealing with geometric source terms. When applied to the shallow water equations, the proposed HLLS-ADER and AR-ADER schemes can be constructed to fulfill the exactly well-balanced property, showing that an arbitrary quadrature of the integral of the source inside the cell does not ensure energy balanced solutions. As a result of this work, energy balanced flux-ADER schemes that provide the exact solution for steady cases and that converge to the exact solution with arbitrary order for transient cases are constructed.

Quantification of uncertainties in source term estimates for a BWR with Mark I containment

International Nuclear Information System (INIS)

Khatib-Rahbar, M.; Cazzoli, E.; Davis, R.; Ishigami, T.; Lee, M.; Nourbakhsh, H.; Schmidt, E.; Unwin, S.

1988-01-01

A methodology for quantification and uncertainty analysis of source terms for severe accident in light water reactors (QUASAR) has been developed. The objectives of the QUASAR program are (1) to develop a framework for performing an uncertainty evaluation of the input parameters of the phenomenological models used in the Source Term Code Package (STCP), and (2) to quantify the uncertainties in certain phenomenological aspects of source terms (that are not modeled by STCP) using state-of-the-art methods. The QUASAR methodology consists of (1) screening sensitivity analysis, where the most sensitive input variables are selected for detailed uncertainty analysis, (2) uncertainty analysis, where probability density functions (PDFs) are established for the parameters identified by the screening stage and propagated through the codes to obtain PDFs for the outputs (i.e., release fractions to the environment), and (3) distribution sensitivity analysis, which is performed to determine the sensitivity of the output PDFs to the input PDFs. In this paper attention is limited to a single accident progression sequence, namely; a station blackout accident in a BWR with a Mark I containment buildings. Identified as an important accident in the draft NUREG-1150 a station blackout involves loss of both off-site power and DC power resulting in failure of the diesels to start and in the unavailability of the high pressure injection and core isolation coding systems

PHENOstruct: Prediction of human phenotype ontology terms using heterogeneous data sources.

Science.gov (United States)

Kahanda, Indika; Funk, Christopher; Verspoor, Karin; Ben-Hur, Asa

2015-01-01

The human phenotype ontology (HPO) was recently developed as a standardized vocabulary for describing the phenotype abnormalities associated with human diseases. At present, only a small fraction of human protein coding genes have HPO annotations. But, researchers believe that a large portion of currently unannotated genes are related to disease phenotypes. Therefore, it is important to predict gene-HPO term associations using accurate computational methods. In this work we demonstrate the performance advantage of the structured SVM approach which was shown to be highly effective for Gene Ontology term prediction in comparison to several baseline methods. Furthermore, we highlight a collection of informative data sources suitable for the problem of predicting gene-HPO associations, including large scale literature mining data.

Radioiodine source term and its potential impact on the use of potassium iodide

International Nuclear Information System (INIS)

Malinauskas, A.P.

1982-01-01

Information is presented concerning chemical forms of fission product iodine in the primary circuit; chemical forms of fission product iodine in the containment building; summary of iodine chemistry in light water reactor accidents; and impact of the radiodine source term on the potassium iodide issue

Update Knowledge Base for Long-term Core Cooling Reliability

International Nuclear Information System (INIS)

Agrell, Maria; Sandervag, Oddbjoern; Amri, Abdallah; ); Bang, Young S.; Blomart, Philippe; Broecker, Annette; Pointner, Winfried; Ganzmann, Ingo; Lenogue, Bruno; Guzonas, David; Herer, Christophe; Mattei, Jean-Marie; Tricottet, Matthieu; Masaoka, Hideaki; Soltesz, Vojtech; Tarkiainen, Seppo; Ui, Atsushi; Villalba, Cristina; Zigler, Gilbert

2013-11-01

This revision of the Knowledge Base for Emergency Core Cooling System Recirculation Reliability (NEA/CSNI/R (95)11) describes the current status (late 2012) of the knowledge base on emergency core cooling system (ECCS) and containment spray system (CSS) suction strainer performance and long-term cooling in operating power reactors. New reactors, such as the AP1000, EPR and APR1400 that are under construction in some Organization for Economic Co-operation and Development (OECD) member countries, are not addressed in detail in this revision. The containment sump (also known as the emergency or recirculation sump in pressurized water reactors (PWRs) and pressurized heavy water reactors (PHWRs) or the suppression pools or wet wells in boiling water reactors (BWRs)) and associated ECCS strainers are parts of the ECCS in both reactor types. All nuclear power plants (NPPs) are required to have an ECCS that is capable of mitigating a design basis accident (DBA). The containment sump collects reactor coolant, ECCS injection water, and containment spray solutions, if applicable, after a loss-of-coolant accident (LOCA). The sump serves as the water source to support long-term recirculation for residual heat removal, emergency core cooling, and containment atmosphere clean-up. This water source, the related pump suction inlets, and the piping between the source and inlets are important safety-related components. In addition, if fibrous material is deposited at the fuel element spacers, core cooling can be endangered. The performance of ECCS/CSS strainers was recognized many years ago as an important regulatory and safety issue. One of the primary concerns is the potential for debris generated by a jet of high-pressure coolant during a LOCA to clog the strainer and obstruct core cooling. The issue was considered resolved for all reactor types in the mid-1990s and the OECD/NEA/CSNI published report NEA/CSNI/R(95)11 in 1996 to document the state of knowledge of ECCS performance

Accelerator-based intense neutron source for materials R ampersand D

International Nuclear Information System (INIS)

Jameson, R.A.

1990-01-01

Accelerator-based neutron sources for R ampersand D of materials in nuclear energy systems, including fusion reactors, can provide sufficient neutron flux, flux-volume, fluence and other attractive features for many aspects of materials research. The neutron spectrum produced from the D-Li reaction has been judged useful for many basic materials research problems, and to be a satisfactory approximation to that of the fusion process. The technology of high-intensity linear accelerators can readily be applied to provide the deuteron beam for the neutron source. Earlier applications included the Los Alamos Meson Physics Facility and the Fusion Materials Irradiation Test facility prototype. The key features of today's advanced accelerator technology are presented to illustrate the present state-of-the-art in terms of improved understanding of basic physical principles and engineering technique, and to show how these advances can be applied to present demands in a timely manner. These features include how to produce an intense beam current with the high quality required to minimize beam losses along the accelerator and transport system that could cause maintenance difficulties, by controlling the beam emittance through proper choice of the operating frequency, balancing of the forces acting on the beam, and realization in practical hardware. A most interesting aspect for materials researchers is the increased flexibility and opportunities for experimental configurations that a modern accelerator-based source could add to the set of available tools. 8 refs., 5 figs

The development of a realistic source term for sodium-cooled fast reactors : assessment of current status and future needs.

Energy Technology Data Exchange (ETDEWEB)

LaChance, Jeffrey L.; Phillips, Jesse; Parma, Edward J., Jr.; Olivier, Tara Jean; Middleton, Bobby D.

2011-06-01

Sodium-cooled fast reactors (SFRs) continue to be proposed and designed throughout the United States and the world. Although the number of SFRs actually operating has declined substantially since the 1980s, a significant interest in advancing these types of reactor systems remains. Of the many issues associated with the development and deployment of SFRs, one of high regulatory importance is the source term to be used in the siting of the reactor. A substantial amount of modeling and experimental work has been performed over the past four decades on accident analysis, sodium coolant behavior, and radionuclide release for SFRs. The objective of this report is to aid in determining the gaps and issues related to the development of a realistic, mechanistically derived source term for SFRs. This report will allow the reader to become familiar with the severe accident source term concept and gain a broad understanding of the current status of the models and experimental work. Further, this report will allow insight into future work, in terms of both model development and experimental validation, which is necessary in order to develop a realistic source term for SFRs.

Modeling of Radiotherapy Linac Source Terms Using ARCHER Monte Carlo Code: Performance Comparison for GPU and MIC Parallel Computing Devices

Directory of Open Access Journals (Sweden)

Lin Hui

2017-01-01

Full Text Available Monte Carlo (MC simulation is well recognized as the most accurate method for radiation dose calculations. For radiotherapy applications, accurate modelling of the source term, i.e. the clinical linear accelerator is critical to the simulation. The purpose of this paper is to perform source modelling and examine the accuracy and performance of the models on Intel Many Integrated Core coprocessors (aka Xeon Phi and Nvidia GPU using ARCHER and explore the potential optimization methods. Phase Space-based source modelling for has been implemented. Good agreements were found in a tomotherapy prostate patient case and a TrueBeam breast case. From the aspect of performance, the whole simulation for prostate plan and breast plan cost about 173s and 73s with 1% statistical error.

A well-balanced scheme for Ten-Moment Gaussian closure equations with source term

Science.gov (United States)

Meena, Asha Kumari; Kumar, Harish

2018-02-01

In this article, we consider the Ten-Moment equations with source term, which occurs in many applications related to plasma flows. We present a well-balanced second-order finite volume scheme. The scheme is well-balanced for general equation of state, provided we can write the hydrostatic solution as a function of the space variables. This is achieved by combining hydrostatic reconstruction with contact preserving, consistent numerical flux, and appropriate source discretization. Several numerical experiments are presented to demonstrate the well-balanced property and resulting accuracy of the proposed scheme.

Review of the status of validation of the computer codes used in the severe accident source term reassessment study (BMI-2104)

International Nuclear Information System (INIS)

Kress, T.S.

1985-04-01

The determination of severe accident source terms must, by necessity it seems, rely heavily on the use of complex computer codes. Source term acceptability, therefore, rests on the assessed validity of such codes. Consequently, one element of NRC's recent efforts to reassess LWR severe accident source terms is to provide a review of the status of validation of the computer codes used in the reassessment. The results of this review is the subject of this document. The separate review documents compiled in this report were used as a resource along with the results of the BMI-2104 study by BCL and the QUEST study by SNL to arrive at a more-or-less independent appraisal of the status of source term modeling at this time

An accelerator based steady state neutron source

International Nuclear Information System (INIS)

Burke, R.J.; Johnson, D.L.

1985-01-01

Using high current, c.w. linear accelerator technology, a spallation neutron source can achieve much higher average intensities than existing or proposed pulsed spallation sources. With about 100 mA of 300 MeV protons or deuterons, the Accelerator Based Neutron Research Facility (ABNR) would initially achieve the 10 16 n/cm 2 .s thermal flux goal of the advanced steady state neutron source, and upgrading could provide higher steady state fluxes. The relatively low ion energy compared to other spallation sources has an important impact on R and D requirements as well as capital cost, for which a range of $300-450M is estimated by comparison to other accelerator-based neutron source facilities. The source is similar to a reactor source in most respects. It has some higher energy neutrons but fewer gamma rays, and the moderator region is free of many of the design constraints of a reactor, which helps to implement sources for various neutron energy spectra, many beam tubes, etc. With the development of multi-beam concept and the basis for currents greater than 100 mA that is assumed in the R and D plan, the ABNR would serve many additional uses, such as fusion materials development, production of proton-rich isotopes, and other energy and defense program needs

Source term assessment using inverse modeling of radiation dose measured with environmental radiation monitors located at different positions

International Nuclear Information System (INIS)

Srinivas, C.V.; Rakesh, P.T.; Baskaran, R.; Venkatraman, B.

2018-01-01

Source term is an important input for consequence analysis using Decision Support Systems (DSS) to project radiological impact in the event of nuclear emergencies. A source term model called 'ASTER' is incorporated in the Online Nuclear Emergency Response System (ONERS) operational at Kalpakkam site for decision making during nuclear emergencies. This computes release rates using inverse method by employing an atmospheric dispersion model and gamma dose rates measured by environmental radiation monitors (ERM) deployed around the nuclear plant. The estimates may depend on the distribution of ERMs around the release location. In this work, data from various gamma monitors located at different radii 0.75 km and 1.5 km is used to assess the accuracy in the source term estimation for stack releases of MAPS-PHWR at Kalpakkam

Open Source Cloud-Based Technologies for Bim

Science.gov (United States)

Logothetis, S.; Karachaliou, E.; Valari, E.; Stylianidis, E.

2018-05-01

This paper presents a Cloud-based open source system for storing and processing data from a 3D survey approach. More specifically, we provide an online service for viewing, storing and analysing BIM. Cloud technologies were used to develop a web interface as a BIM data centre, which can handle large BIM data using a server. The server can be accessed by many users through various electronic devices anytime and anywhere so they can view online 3D models using browsers. Nowadays, the Cloud computing is engaged progressively in facilitating BIM-based collaboration between the multiple stakeholders and disciplinary groups for complicated Architectural, Engineering and Construction (AEC) projects. Besides, the development of Open Source Software (OSS) has been rapidly growing and their use tends to be united. Although BIM and Cloud technologies are extensively known and used, there is a lack of integrated open source Cloud-based platforms able to support all stages of BIM processes. The present research aims to create an open source Cloud-based BIM system that is able to handle geospatial data. In this effort, only open source tools will be used; from the starting point of creating the 3D model with FreeCAD to its online presentation through BIMserver. Python plug-ins will be developed to link the two software which will be distributed and freely available to a large community of professional for their use. The research work will be completed by benchmarking four Cloud-based BIM systems: Autodesk BIM 360, BIMserver, Graphisoft BIMcloud and Onuma System, which present remarkable results.

OPEN SOURCE CLOUD-BASED TECHNOLOGIES FOR BIM

Directory of Open Access Journals (Sweden)

S. Logothetis

2018-05-01

Full Text Available This paper presents a Cloud-based open source system for storing and processing data from a 3D survey approach. More specifically, we provide an online service for viewing, storing and analysing BIM. Cloud technologies were used to develop a web interface as a BIM data centre, which can handle large BIM data using a server. The server can be accessed by many users through various electronic devices anytime and anywhere so they can view online 3D models using browsers. Nowadays, the Cloud computing is engaged progressively in facilitating BIM-based collaboration between the multiple stakeholders and disciplinary groups for complicated Architectural, Engineering and Construction (AEC projects. Besides, the development of Open Source Software (OSS has been rapidly growing and their use tends to be united. Although BIM and Cloud technologies are extensively known and used, there is a lack of integrated open source Cloud-based platforms able to support all stages of BIM processes. The present research aims to create an open source Cloud-based BIM system that is able to handle geospatial data. In this effort, only open source tools will be used; from the starting point of creating the 3D model with FreeCAD to its online presentation through BIMserver. Python plug-ins will be developed to link the two software which will be distributed and freely available to a large community of professional for their use. The research work will be completed by benchmarking four Cloud-based BIM systems: Autodesk BIM 360, BIMserver, Graphisoft BIMcloud and Onuma System, which present remarkable results.

Final report of the inter institutional project ININ-CNSNS 'Source Terms specific for the CNLV'

International Nuclear Information System (INIS)

Anaya M, R.A.

1991-02-01

The purpose of the project inter institutional ININ-CNSNS 'Source Terms Specifies for the CNLV' it is the one of implanting in the computer CYBER (CDC 180-830) of the ININ, the 'Source Term Code Package' (STCP) and to make the operation tests and corresponding operation using the data of the sample problem, for finally to liberate the package, all time that by means of the analysis of the results it is consider appropriate. In this report the results of the are presented simulation of the sequence 'Energy Losses external' (Station blackout) and 'Lost total of CA with failure of the RCIC and success of the HPCS' both with data of the Laguna Verde Central. (Author)

Jet flow analysis of liquid poison injection in a CANDU reactor using source term

International Nuclear Information System (INIS)

Chae, Kyung Myung; Choi, Hang Bok; Rhee, Bo Wook

2001-01-01

For the performance analysis of Canadian deuterium uranium (CANDU) reactor shutdown system number 2 (SDS2), a computational fluid dynamics model of poison jet flow has been developed to estimate the flow field and poison concentration formed inside the CANDU reactor calandria. As the ratio of calandria shell radius over injection nozzle hole diameter is so large (1055), it is impractical to develop a full-size model encompassing the whole calandria shell. In order to reduce the model to a manageable size, a quarter of one-pitch length segment of the shell was modeled using symmetric nature of the jet; and the injected jet was treated as a source term to avoid the modeling difficulty caused by the big difference of the hole sizes. For the analysis of an actual CANDU-6 SDS2 poison injection, the grid structure was determined based on the results of two-dimensional real- and source-jet simulations. The maximum injection velocity of the liquid poison is 27.8 m/s and the mass fraction of the poison is 8000 ppm (mg/kg). The simulation results have shown well-established jet flow field. In general, the jet develops narrowly at first but stretches rapidly. Then, the flow recirculates a little in r-x plane, while it recirculates largely in r-θ plane. As the time goes on, the adjacent jets contact each other and form a wavy front such that the whole jet develops in a plate form. his study has shown that the source term model can be effectively used for the analysis of the poison injection and the simulation result of the CANDU reactor is consistent with the model currently being used for the safety analysis. In the future, it is strongly recommended to analyze the transient (from helium tank to injection nozzle hole) of the poison injection by applying Bernoulli equation with real boundary conditions

Energy-Based Acoustic Source Localization Methods: A Survey

Directory of Open Access Journals (Sweden)

Wei Meng

2017-02-01

Full Text Available Energy-based source localization is an important problem in wireless sensor networks (WSNs, which has been studied actively in the literature. Numerous localization algorithms, e.g., maximum likelihood estimation (MLE and nonlinear-least-squares (NLS methods, have been reported. In the literature, there are relevant review papers for localization in WSNs, e.g., for distance-based localization. However, not much work related to energy-based source localization is covered in the existing review papers. Energy-based methods are proposed and specially designed for a WSN due to its limited sensor capabilities. This paper aims to give a comprehensive review of these different algorithms for energy-based single and multiple source localization problems, their merits and demerits and to point out possible future research directions.

Future Synchrotron Light Sources Based on Ultimate Storage Rings

International Nuclear Information System (INIS)

Cai, Yunhai

2012-01-01

The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic cell, we

Future Synchrotron Light Sources Based on Ultimate Storage Rings

Energy Technology Data Exchange (ETDEWEB)

Cai, Yunhai; /SLAC

2012-04-09

The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend

ORIGAMI Automator Primer. Automated ORIGEN Source Terms and Spent Fuel Storage Pool Analysis

Energy Technology Data Exchange (ETDEWEB)

Wieselquist, William A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Thompson, Adam B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bowman, Stephen M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peterson, Joshua L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-04-01

Source terms and spent nuclear fuel (SNF) storage pool decay heat load analyses for operating nuclear power plants require a large number of Oak Ridge Isotope Generation and Depletion (ORIGEN) calculations. SNF source term calculations also require a significant amount of bookkeeping to track quantities such as core and assembly operating histories, spent fuel pool (SFP) residence times, heavy metal masses, and enrichments. The ORIGEN Assembly Isotopics (ORIGAMI) module in the SCALE code system provides a simple scheme for entering these data. However, given the large scope of the analysis, extensive scripting is necessary to convert formats and process data to create thousands of ORIGAMI input files (one per assembly) and to process the results into formats readily usable by follow-on analysis tools. This primer describes a project within the SCALE Fulcrum graphical user interface (GUI) called ORIGAMI Automator that was developed to automate the scripting and bookkeeping in large-scale source term analyses. The ORIGAMI Automator enables the analyst to (1) easily create, view, and edit the reactor site and assembly information, (2) automatically create and run ORIGAMI inputs, and (3) analyze the results from ORIGAMI. ORIGAMI Automator uses the standard ORIGEN binary concentrations files produced by ORIGAMI, with concentrations available at all time points in each assembly’s life. The GUI plots results such as mass, concentration, activity, and decay heat using a powerful new ORIGEN Post-Processing Utility for SCALE (OPUS) GUI component. This document includes a description and user guide for the GUI, a step-by-step tutorial for a simplified scenario, and appendices that document the file structures used.

Source term development for tritium at the Sheffield disposal site

International Nuclear Information System (INIS)

MacKenzie, D.R.; Barletta, R.E.; Smalley, J.F.; Kempf, C.R.; Davis, R.E.

1984-01-01

The Sheffield low-level radioactive waste disposal site, which ceased operation in 1978, has been the focus of modeling efforts by the NRC for the purpose of predicting long-term site behavior. To provide the NRC with the information required for its modeling effort, a study to define the source term for tritium in eight trenches at the Sheffield site has been undertaken. Tritium is of special interest since significant concentrations of the isotope have been found in groundwater samples taken at the site and at locations outside the site boundary. Previous estimates of tritium site inventory at Sheffield are in wide disagreement. In this study, the tritium inventory in the eight trenches was estimated by reviewing the radioactive shipping records (RSRs) for waste buried in these trenches. It has been found that the tritium shipped for burial at the site was probably higher than previously estimated. In the eight trenches surveyed, which amount to roughly one half the total volume and activity buried at Sheffield, approximately 2350 Ci of tritium from non-fuel cycle sources were identified. The review of RSRs also formed the basis for obtaining waste package descriptions and for contacting large waste generators to obtain more detailed information regarding these waste packages. As a result of this review and the selected generator contacts, the non-fuel cycle tritium waste was categorized. The tritium releases from each of these waste categories were modeled. The results of this modeling effort are presented for each of the eight trenches selected. 3 references, 2 figures

Projected Source Terms for Potential Sabotage Events Related to Spent Fuel Shipments

International Nuclear Information System (INIS)

Luna, R.E.; Neuhauser, K.S.; Vigil, M.G.

1999-01-01

Two major studies, one sponsored by the U.S. Department of Energy and the other by the U.S. Nuclear Regulatory Commission, were conducted in the late 1970s and early 1980s to provide information and source terms for an optimally successful act of sabotage on spent fuel casks typical of those available for use. This report applies the results of those studies and additional analysis to derive potential source terms for certain classes of sabotage events on spent fuel casks and spent fuel typical of those which could be shipped in the early decades of the 21st century. In addition to updating the cask and spent fuel characteristics used in the analysis, two release mechanisms not included in the earlier works were identified and evaluated. As would be expected, inclusion of these additional release mechanisms resulted in a somewhat higher total release from the postulated sabotage events. Although health effects from estimated releases were addressed in the earlier study conducted for U.S. Department of Energy, they have not been addressed in this report. The results from this report maybe used to estimate health effects

DUSTMS-D: DISPOSAL UNIT SOURCE TERM - MULTIPLE SPECIES - DISTRIBUTED FAILURE DATA INPUT GUIDE.

Energy Technology Data Exchange (ETDEWEB)

SULLIVAN, T.M.

2006-01-01

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 source term). The focus of this work is to develop a methodology for calculating the source term. In general, the source term is influenced by the radionuclide inventory, the wasteforms and containers used to dispose of the inventory, and the physical processes that lead to release from the facility (fluid flow, container degradation, wasteform leaching, and radionuclide transport). Many of these physical processes are influenced by the design of the disposal facility (e.g., how the engineered barriers control infiltration of water). The complexity of the problem and the absence of appropriate data prevent development of an entirely mechanistic representation of radionuclide release from a disposal facility. Typically, a number of assumptions, based on knowledge of the disposal system, are used to simplify the problem. This has been done and the resulting models have been incorporated into the computer code DUST-MS (Disposal Unit Source Term-Multiple Species). The DUST-MS computer code is designed to model water flow, container degradation, release of contaminants from the wasteform to the contacting solution and transport through the subsurface media. Water flow through the facility over time is modeled using tabular input. Container degradation models include three types of failure rates: (a) instantaneous (all containers in a control volume fail at once), (b) uniformly distributed failures (containers fail at a linear rate between a specified starting and ending time), and (c) gaussian failure rates (containers fail at a rate determined by a mean failure time, standard deviation and gaussian distribution). Wasteform release models include four release mechanisms: (a) rinse with partitioning (inventory is released instantly upon container failure subject to equilibrium partitioning (sorption) with

Wearable energy sources based on 2D materials.

Science.gov (United States)

Yi, Fang; Ren, Huaying; Shan, Jingyuan; Sun, Xiao; Wei, Di; Liu, Zhongfan

2018-05-08

Wearable energy sources are in urgent demand due to the rapid development of wearable electronics. Besides flexibility and ultrathin thickness, emerging 2D materials present certain extraordinary properties that surpass the properties of conventional materials, which make them advantageous for high-performance wearable energy sources. Here, we provide a comprehensive review of recent advances in 2D material based wearable energy sources including wearable batteries, supercapacitors, and different types of energy harvesters. The crucial roles of 2D materials in the wearable energy sources are highlighted. Based on the current progress, the existing challenges and future prospects are outlined and discussed.

Strong source heat transfer simulations based on a GalerKin/Gradient - least - squares method

International Nuclear Information System (INIS)

Franca, L.P.; Carmo, E.G.D. do.

1989-05-01

Heat conduction problems with temperature-dependent strong sources are modeled by an equation with a laplacian term, a linear term and a given source distribution term. When the linear-temperature-dependent source term is much larger than the laplacian term, we have a singular perturbation problem. In this case, boundary layers are formed to satisfy the Dirichlet boundary conditions. Although this is an elliptic equation, the standard Galerkin method solution is contaminated by spurious oscillations in the neighborhood of the boundary layers. Herein we employ a Galerkin/Gradient-least-squares method which eliminates all pathological phenomena of the Galerkin method. The method is constructed by adding to the Galerkin method a mesh-dependent term obtained by the least-squares form of the gradient of the Euler-Lagrange equation. Error estimates, numerical simulations in one-and multi-dimensions are given that attest the good stability and accuracy properties of the method [pt

Manufacturing of large size RF based -ve ion source with 8 drivers-challenges and learnings

International Nuclear Information System (INIS)

Joshi, Jaydeep; Patel, Hitesh; Singh, Mahendrajit; Bandyopadhyay, Mainak; Chakraborty, Arun

2017-01-01

Radio Frequency (RF) Ion Source for ITER Diagnostic Neutral Beam (DNB) system, is an 8 driver based ion source, where the desired plasma density is produced by inductive coupling of RF power. The present paper describes the experience of developing a manufacturing design to meet the above mentioned requirements, feasibility assessment, prototyping carried out, parallel experiments in support of manufacturing and realization of sub-components along with their quality inspections activities performed. Additionally, paper also presents to the observations in terms of deviations and non-conformities encountered, as a part of learning for the future components

Basic repository source term and data sheet report: Deaf Smith County

International Nuclear Information System (INIS)

1987-01-01

This report is one of a series describing studies undertaken in support of the US Department of Energy Civilian Radioactive Waste Management (CRWM) Program. This study contains the derivation of values for environmental source terms and resources consumed for a CRWM repository. Estimates include heavy construction equipment; support equipment; shaft-sinking equipment; transportation equipment; and consumption of fuel, water, electricity, and natural gas. Data are presented for construction and operation at an assumed site in Deaf Smith County, Texas. 2 refs., 6 tabs

Design parameters and source terms: Volume 1, Design parameters: Revision 0

International Nuclear Information System (INIS)

1987-09-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan - Conceptual Design Report, SCP-CDR. The previous unpublished SCC Study identified the data needs for the Environmental Assessment effort for seven possible salt repository sites

Sourcing Team Behavior in Project-Based MNE's

DEFF Research Database (Denmark)

Hansen, Anders Peder Lysholm

2014-01-01

across the three cases was characterized by conflict between departments represented in the category teams. This resulted in unfortunate sourcing team behaviour and unaligned performance management, which in turn had a number of adverse effects. Further research on how to create a holistic and balanced......This paper presents and discusses a multiple case study of three cross-functional category teams responsible for sourcing critical components within multi-national, project-based enterprises. The study focused on behaviour and management of the sourcing teams and found that the sourcing process...... team perspective in the sourcing teams is suggested....

New source terms: what do they tell us about engineered safety feature performance

International Nuclear Information System (INIS)

Bernero, R.M.

1985-01-01

The accident behavior models which are the basis of engineered safety feature design are generally simple, non-mechanistic and concentrated on volatile radioiodine. Now data from source term studies show that models should be more mechanistic and look at other species than volatile iodine. A complete reevaluation of engineered safety features is needed

Cyclotron-based neutron source for BNCT

Energy Technology Data Exchange (ETDEWEB)

Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

2013-04-19

Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

Evaluation of the Non-Transient Hydrologic Source Term from the CAMBRIC Underground Nuclear Test in Frenchman Flat, Nevada Test Site

International Nuclear Information System (INIS)

Tompson, A B; Maxwell, R M; Carle, S F; Zavarin, M; Pawloski, G A.; Shumaker, D E

2005-01-01

Hydrologic Source Term (HST) calculations completed in 1998 at the CAMBRIC underground nuclear test site were LLNL's first attempt to simulate a hydrologic source term at the NTS by linking groundwater flow and transport modeling with geochemical modeling (Tompson et al., 1999). Significant effort was applied to develop a framework that modeled in detail the flow regime and captured all appropriate chemical processes that occurred over time. However, portions of the calculations were simplified because of data limitations and a perceived need for generalization of the results. For example: (1) Transient effects arising from a 16 years of pumping at the site for a radionuclide migration study were not incorporated. (2) Radionuclide fluxes across the water table, as derived from infiltration from a ditch to which pumping effluent was discharged, were not addressed. (3) Hydrothermal effects arising from residual heat of the test were not considered. (4) Background data on the ambient groundwater flow direction were uncertain and not represented. (5) Unclassified information on the Radiologic Source Term (RST) inventory, as tabulated recently by Bowen et al. (2001), was unavailable; instead, only a limited set of derived data were available (see Tompson et al., 1999). (6) Only a small number of radionuclides and geochemical reactions were incorporated in the work. (7) Data and interpretation of the RNM-2S multiple well aquifer test (MWAT) were not available. As a result, the current Transient CAMBRIC Hydrologic Source Term project was initiated as part of a broader Phase 2 Frenchman Flat CAU flow and transport modeling effort. The source term will be calculated under two scenarios: (1) A more specific representation of the transient flow and radionuclide release behavior at the site, reflecting the influence of the background hydraulic gradient, residual test heat, pumping experiment, and ditch recharge, and taking into account improved data sources and modeling

MIT/OSO 7 catalog of x-ray sources: intensities, spectra, and long-term variability

International Nuclear Information System (INIS)

Markert, T.H.; Winkler, P.F.; Laird, F.N.; Clark, G.W.; Hearn, D.R.; Sprott, G.F.; Li, F.K.; Bradt, H.V.; Lewin, W.H.G.; Schnopper, H.W.

1979-01-01

This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1--40 KeV X-ray detectors on the OSO 7 between 1971 October and 1973 May. Specifically, we have computed the mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3--10 KeV range. For those sources for which a statistically significant (>20) intensity was found in the 3--10 KeV band (138 sources), further intensity determinations were made in the 1--15 KeV, 1--6 KeV, and 15--40 KeV energy bands. We have provided graphs and other simple techniques to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Finally, we have plotted long-term light curves (counting rates in one or more energy bands as a function of time) for 86 of the brighter sources

Source term and behavioural parameters for a postulated HIFAR loss-of-coolant accident

International Nuclear Information System (INIS)

May, F.G.

1987-01-01

The fraction of the fission product inventory which might be released into the atmosphere of the HIFAR reactor containment building (RCB) during a postulated loss-of-coolant accident (LOCA) has been evaluated as a function of time, for each classification of airborne radioactivity. This appraisal will be used as the source term for a computer program, which uses realistic attenuation of the fission product aerosol in a single compartment model with a defined leakrate to predict possible radioactive releases into the environment in a hypothetical bounding case reactor accident which is rather more severe in all major aspects than any single LOCA. Also given are the parameters governing the attenuation of the aerosol and vapours in the atmosphere of the RCB so that their behaviour may be accurately modelled. The source terms for several other types of accident involving the meltdown of fuel elements have also been considered but in less detail than the LOCA case. In some of the cases, the fission products are released directly to atmosphere, so there is no attenuation of the release by deposition within the RCB

Determination of source terms in a degenerate parabolic equation

International Nuclear Information System (INIS)

Cannarsa, P; Tort, J; Yamamoto, M

2010-01-01

In this paper, we prove Lipschitz stability results for inverse source problems relative to parabolic equations. We use the method introduced by Imanuvilov and Yamamoto in 1998 based on Carleman estimates. What is new here is that we study a class of one-dimensional degenerate parabolic equations. In our model, the diffusion coefficient vanishes at one extreme point of the domain. Instead of the classical Carleman estimates obtained by Fursikov and Imanuvilov for non degenerate equations, we use and extend some recent Carleman estimates for degenerate equations obtained by Cannarsa, Martinez and Vancostenoble. Finally, we obtain Lipschitz stability results in inverse source problems for our class of degenerate parabolic equations both in the case of a boundary observation and in the case of a locally distributed observation

Reciprocity relations and the mode conversion-absorption equation with an inhomogeneous source term

International Nuclear Information System (INIS)

Cho, S.; Swanson, D.G.

1990-01-01

The fourth-order mode conversion equation is solved completely via the Green's function to include an inhomogeneous source term. This Green's function itself contains all the plasma responsive effects such as mode conversion and absorption, and can be used to describe the spontaneous emission. In the course of the analysis, the reciprocity relations between coupling parameters are proved

High-brightness electron guns for linac-based light sources

International Nuclear Information System (INIS)

Lewellen, J.W.

2004-01-01

Most proposed linac-based light sources, such as single-pass free-electron lasers and energy-recovery-linacs, require very high-brightness electron beams in order to achieve their design performance. These beam requirements must be achieved not on an occasional basis, but rather must be met by every bunch produced by the source over extended periods of time. It is widely assumed that the beam source will be a photocathode electron gun; the selection of accelerator technique (e.g., dc or rf) for the gun is more dependent on the application.The current state of the art of electron beam production is adequate but not ideal for the first generation of linac-based light sources, such as the Linac Coherent Light Source (LCLS) x-ray free-electron laser (X-FEL). For the next generation of linac-based light sources, an order of magnitude reduction in the transverse electron beam emittance is required to significantly reduce the cost of the facility. This is beyond the present state of the art, given the other beam properties that must be maintained. The requirements for current and future linac-based light source beam sources are presented here, along with a review of the present state of the art. A discussion of potential paths towards meeting future needs is presented at the conclusion.

The EC CAST project (carbon-14 source term)

International Nuclear Information System (INIS)

Williams, S. J.

2015-01-01

Carbon-14 is a key radionuclide in the assessment of the safety of underground geological disposal facilities for radioactive wastes. It is possible for carbon-14 to be released from waste packages in a variety of chemical forms, both organic and inorganic, and as dissolved or gaseous species The EC CAST (CArbon-14 Source Term) project aims to develop understanding of the generation and release of carbon-14 from radioactive waste materials under conditions relevant to packaging and disposal. It focuses on the release of carbon-14 from irradiated metals (steels and zirconium alloys), from irradiated graphite and from spent ion-exchange resins. The CAST consortium brings together 33 partners. CAST commenced in October 2013 and this paper describes progress to March 2015. The main activities during this period were reviews of the current status of knowledge, the identification and acquisition of suitable samples and the design of experiments and analytical procedures. (authors)

LED-based UV source for monitoring spectroradiometer properties

Science.gov (United States)

Sildoja, Meelis-Mait; Nevas, Saulius; Kouremeti, Natalia; Gröbner, Julian; Pape, Sven; Pendsa, Stefan; Sperfeld, Peter; Kemus, Fabian

2018-06-01

A compact and stable UV monitoring source based on state-of-the-art commercially available ultraviolet light emitting diodes (UV-LEDs) has been developed. It is designed to trace the radiometric stability—both responsivity and wavelength scale—of array spectroradiometers measuring direct solar irradiance in the wavelength range between 300 nm and 400 nm. The spectral irradiance stability of the UV-LED-based light source observed in the laboratory after seasoning (burning-in) the individual LEDs was better than 0.3% over a 12 h period of continuous operation. The integral irradiance measurements of the source over a period of several months, where the UV-LED source was not operated continuously between the measurements, showed stability within 0.3%. In-field measurements of the source with an array spectroradiometer indicated the stability of the source to be within the standard uncertainty of the spectroradiometer calibration, which was within 1% to 2%.

Network of anatomical texts (NAnaTex), an open-source project for visualizing the interaction between anatomical terms.

Science.gov (United States)

Momota, Ryusuke; Ohtsuka, Aiji

2018-01-01

Anatomy is the science and art of understanding the structure of the body and its components in relation to the functions of the whole-body system. Medicine is based on a deep understanding of anatomy, but quite a few introductory-level learners are overwhelmed by the sheer amount of anatomical terminology that must be understood, so they regard anatomy as a dull and dense subject. To help them learn anatomical terms in a more contextual way, we started a new open-source project, the Network of Anatomical Texts (NAnaTex), which visualizes relationships of body components by integrating text-based anatomical information using Cytoscape, a network visualization software platform. Here, we present a network of bones and muscles produced from literature descriptions. As this network is primarily text-based and does not require any programming knowledge, it is easy to implement new functions or provide extra information by making changes to the original text files. To facilitate collaborations, we deposited the source code files for the network into the GitHub repository ( https://github.com/ryusukemomota/nanatex ) so that anybody can participate in the evolution of the network and use it for their own non-profit purposes. This project should help not only introductory-level learners but also professional medical practitioners, who could use it as a quick reference.

Loss of confinement of liquefied gases. Evaluation of the source term; Perte de confinement de gaz liquefies. Evaluation du terme source

Energy Technology Data Exchange (ETDEWEB)

Alix, P.; Novat, E.; Hocquet, J.; Bigot, J.P. [Ecole Nationale Superieure des Mines, Centre SPIN, 42 - Saint-Etienne (France)

2001-07-01

In this work, the states law corresponding to flow rate measurements of two-phase flows performed with five different fluid (water, butane, R11, ethyl acetate, methanol) is applied. This allows to show that the critical mass flux (which is used as source term in the scenario of loss of confinement in liquefied gas reservoirs) is a 'universal' function of the reduced initial pressure P{sub 0}{sup *}, which can be used for most of the single-constituent fluids of the processes industry. Thus it is easy to make a relatively precise estimation of the critical mass flux (uncertainty < 20% for P{sub 0}{sup *} < 15%) without the need of any model. It is shown also that no improvement of the models can be expected from the use of the vaporization kinetics. On the contrary, a qualitative consideration indicates that the use of the slip seems more promising. (J.S.)

Recent advances in acceleration of source iterations for fixed-source slab-geometry S{sub N} calculations based on P{sub N} synthetic initial guess

Energy Technology Data Exchange (ETDEWEB)

Guida, Mateus Rodrigues; Alves Filho, Hermes; Barros, Ricardo C., E-mail: mguida@iprj.uerj.br, E-mail: halves@iprj.uerj.br, E-mail: rcbarros@pq.cnpq.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico. Programa de Pos-Graduacao em Modelagem Computacional

2015-07-01

The scattering source iterative (SI) scheme is applied traditionally to converge fine-mesh numerical solutions to fixed-source discrete ordinates (S{sub N}) neutron transport problems with linearly anisotropic scattering. The SI scheme is very simple to implement under a computational viewpoint. However, the SI scheme may show very slow convergence rate, mainly for diffusive media (low absorption) with several mean free paths in extent. In this work we describe two acceleration techniques based on improved initial guesses for the SI scheme, wherein we initialize the scattering source distribution within the slab using the P{sub 1} and P{sub 3} approximations. In order to estimate these initial guesses, we use the coarse-mesh solution of the PN equations with special boundary conditions to account for the classical S{sub N} prescribed boundary conditions, including vacuum boundary conditions. To apply this coarse-mesh P{sub N} solution for the accelerated scheme, we first perform within-node spatial reconstruction, and then we determine the fine-mesh average scalar flux and total current for initializing the linearly anisotropic scattering source terms for the SI scheme. We consider a number of numerical experiments to illustrate the efficiency of the offered P{sub N} synthetic acceleration (P{sub N}SA) technique based on initial guess. (author)

How general are general source conditions?

International Nuclear Information System (INIS)

Mathé, Peter; Hofmann, Bernd

2008-01-01

Error analysis of regularization methods in Hilbert spaces is based on smoothness assumptions in terms of source conditions. In the traditional setup, i.e. when smoothness is in a power scale, we see that not all elements in the underlying Hilbert space possess some smoothness with this scale. Our main result asserts that this can be overcome when turning to general source conditions defined in terms of index functions. We conclude with some consequences

Modification to ORIGEN2 for generating N Reactor source terms. Volume 1

International Nuclear Information System (INIS)

Schwarz, R.A.

1997-04-01

This report discusses work that has been done to upgrade the ORIGEN2 code cross sections to be compatible with the WIMS computer code data. Because of the changes in the ORIGEN2 calculations. Details on changes made to the ORIGEN2 computer code and the Radnuc code will be discussed along with additional work that should be done in the future to upgrade both ORIGEN2 and Radnuc. A detailed historical description of how source terms have been generated for N Reactor fuel stored in the K Basins has been generated. The neutron source discussed in this description was generated by the WIMS computer code (Gubbins et al. 1982) because of known shortcomings in the ORIGEN2 (Croff 1980) cross sections. Another document includes a discussion of the ORIGEN2 cross sections

Source Term Characterization for Structural Components in 17 x 17 KOFA Spent Fuel Assembly

Energy Technology Data Exchange (ETDEWEB)

Cho, Dong Keun; Kook, Dong Hak; Choi, Heui Joo; Choi, Jong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-12-15

Source terms of metal waste comprising a spent fuel assembly are relatively important when the spent fuel is pyroprocessed, because cesium, strontium, and transuranics are not a concern any more in the aspect of source term of permanent disposal. In this study, characteristics of radiation source terms for each structural component in spent fuel assembly was analyzed by using ORIGEN-S with a assumption that 10 metric tons of uranium is pyroprocessed. At first, mass and volume for each structural component of the fuel assembly were calculated in detail. Activation cross section library was generated by using KENO-VI/ORIGEN-S module for top-end piece and bottom-end piece, because those are located at outer core with different neutron spectrum compared to that of inner core. As a result, values of radioactivity, decay heat, and hazard index were reveled to be 1.40 x 10{sup 15} Bequerels, 236 Watts, 4.34 x 10{sup 9} m{sup 3}-water, respectively, at 10 years after discharge. Those values correspond to 0.7 %, 1.1 %, 0.1 %, respectively, compared to that of spent fuel. Inconel 718 grid plate was shown to be the most important component in the all aspects of radioactivity, decay heat, and hazard index although the mass occupies only 1 % of the total. It was also shown that if the Inconel 718 grid plate is managed separately, the radioactivity and hazard index of metal waste could be decreased to 20 {approx} 45 % and 30 {approx} 45 %, respectively. As a whole, decay heat of metal waste was shown to be negligible in the aspect of disposal system design, while the radioactivity and hazard index are important.

Model description for calculating the source term of the Angra 1 environmental control system

International Nuclear Information System (INIS)

Oliveira, L.F.S. de; Amaral Neto, J.D.; Salles, M.R.

1988-01-01

This work presents the model used for evaluation of source term released from Angra 1 Nuclear Power Plant in case of an accident. After that, an application of the model for the case of a Fuel Assembly Drop Accident Inside the Fuel Handling Building during reactor refueling is presented. (author) [pt

Source-based neurofeedback methods using EEG recordings: training altered brain activity in a functional brain source derived from blind source separation

Science.gov (United States)

White, David J.; Congedo, Marco; Ciorciari, Joseph

2014-01-01

A developing literature explores the use of neurofeedback in the treatment of a range of clinical conditions, particularly ADHD and epilepsy, whilst neurofeedback also provides an experimental tool for studying the functional significance of endogenous brain activity. A critical component of any neurofeedback method is the underlying physiological signal which forms the basis for the feedback. While the past decade has seen the emergence of fMRI-based protocols training spatially confined BOLD activity, traditional neurofeedback has utilized a small number of electrode sites on the scalp. As scalp EEG at a given electrode site reflects a linear mixture of activity from multiple brain sources and artifacts, efforts to successfully acquire some level of control over the signal may be confounded by these extraneous sources. Further, in the event of successful training, these traditional neurofeedback methods are likely influencing multiple brain regions and processes. The present work describes the use of source-based signal processing methods in EEG neurofeedback. The feasibility and potential utility of such methods were explored in an experiment training increased theta oscillatory activity in a source derived from Blind Source Separation (BSS) of EEG data obtained during completion of a complex cognitive task (spatial navigation). Learned increases in theta activity were observed in two of the four participants to complete 20 sessions of neurofeedback targeting this individually defined functional brain source. Source-based EEG neurofeedback methods using BSS may offer important advantages over traditional neurofeedback, by targeting the desired physiological signal in a more functionally and spatially specific manner. Having provided preliminary evidence of the feasibility of these methods, future work may study a range of clinically and experimentally relevant brain processes where individual brain sources may be targeted by source-based EEG neurofeedback. PMID

Calculation of the isotope concentrations, source terms and radiation shielding of the SAFARI-1 irradiation products

International Nuclear Information System (INIS)

Stoker, C.C.; Ball, G.

2000-01-01

The ever increasing expansion of the irradiation product portfolio of the SAFARI-1 reactor leads to the need to routinely calculate the radio-isotope concentrations and source terms for the materials irradiated in the reactor accurately. In addition to this, the required shielding for the transportation and processing of these irradiation products needs to be determined. In this paper the calculational methodology applied is described with special attention given to the spectrum dependence of the one-group cross sections of selected SAFARI-1 irradiation materials and the consequent effect on the determination of the isotope concentrations and source terms. Comparisons of the calculated isotopic concentrations and dose rates with experimental analysis and measurements provide confidence in the calculational methodologies and data used. (author)

Hiding the Source Based on Limited Flooding for Sensor Networks.

Science.gov (United States)

Chen, Juan; Lin, Zhengkui; Hu, Ying; Wang, Bailing

2015-11-17

Wireless sensor networks are widely used to monitor valuable objects such as rare animals or armies. Once an object is detected, the source, i.e., the sensor nearest to the object, generates and periodically sends a packet about the object to the base station. Since attackers can capture the object by localizing the source, many protocols have been proposed to protect source location. Instead of transmitting the packet to the base station directly, typical source location protection protocols first transmit packets randomly for a few hops to a phantom location, and then forward the packets to the base station. The problem with these protocols is that the generated phantom locations are usually not only near the true source but also close to each other. As a result, attackers can easily trace a route back to the source from the phantom locations. To address the above problem, we propose a new protocol for source location protection based on limited flooding, named SLP. Compared with existing protocols, SLP can generate phantom locations that are not only far away from the source, but also widely distributed. It improves source location security significantly with low communication cost. We further propose a protocol, namely SLP-E, to protect source location against more powerful attackers with wider fields of vision. The performance of our SLP and SLP-E are validated by both theoretical analysis and simulation results.

The use of nonlinear regression analysis for integrating pollutant concentration measurements with atmospheric dispersion modeling for source term estimation

International Nuclear Information System (INIS)

Edwards, L.L.; Freis, R.P.; Peters, L.G.; Gudiksen, P.H.; Pitovranov, S.E.

1993-01-01

The accuracy associated with assessing the environmental consequences of an accidental release of radioactivity is highly dependent on the knowledge of the source term characteristics, which are generally poorly known. The development of an automated numerical technique that integrates the radiological measurements with atmospheric dispersion modeling for more accurate source term estimation is reported. Often, this process of parameter estimation is performed by an emergency response assessor, who takes an intelligent first guess at the model parameters, then, comparing the model results with whatever measurements are available, makes an intuitive, informed next guess of the model parameters. This process may be repeated any number of times until the assessor feels that the model results are reasonable in terms of the measured observations. A new approach, based on a nonlinear least-squares regression scheme coupled with the existing Atmospheric Release Advisory Capability three-dimensional atmospheric dispersion models, is to supplement the assessor's intuition with automated mathematical methods that do not significantly increase the response time of the existing predictive models. The viability of the approach is evaluated by estimation of the known SF 6 tracer release rates associated with the Mesoscale Atmospheric Transport Studies tracer experiments conducted at the Savannah River Laboratory during 1983. These 19 experiments resulted in 14 successful, separate tracer releases with sampling of the tracer plumes along the cross-plume arc situated ∼30 km from the release site

Analysis of accident sequences and source terms at treatment and storage facilities for waste generated by US Department of Energy waste management operations

Energy Technology Data Exchange (ETDEWEB)

Mueller, C.; Nabelssi, B.; Roglans-Ribas, J.; Folga, S.; Policastro, A.; Freeman, W.; Jackson, R.; Mishima, J.; Turner, S.

1996-12-01

This report documents the methodology, computational framework, and results of facility accident analyses performed for the US Department of Energy (DOE) Waste Management Programmatic Environmental Impact Statement (WM PEIS). The accident sequences potentially important to human health risk are specified, their frequencies assessed, and the resultant radiological and chemical source terms evaluated. A personal-computer-based computational framework and database have been developed that provide these results as input to the WM PEIS for the calculation of human health risk impacts. The WM PEIS addresses management of five waste streams in the DOE complex: low-level waste (LLW), hazardous waste (HW), high-level waste (HLW), low-level mixed waste (LLMW), and transuranic waste (TRUW). Currently projected waste generation rates, storage inventories, and treatment process throughputs have been calculated for each of the waste streams. This report summarizes the accident analyses and aggregates the key results for each of the waste streams. Source terms are estimated, and results are presented for each of the major DOE sites and facilities by WM PEIS alternative for each waste stream. Key assumptions in the development of the source terms are identified. The appendices identify the potential atmospheric release of each toxic chemical or radionuclide for each accident scenario studied. They also discuss specific accident analysis data and guidance used or consulted in this report.

Design and Concept of an Energy System Based on Renewable Sources for Greenhouse Sustainable Agriculture

Directory of Open Access Journals (Sweden)

Ioan Aschilean

2018-05-01

Full Text Available Bio-organic greenhouses that are based on alternative resources for producing heat and electricity stand out as an efficient option for the sustainable development of agriculture, thus ensuring good growth and development of plants in all seasons, especially during the cold season. Greenhouses can be used with maximum efficiency in various agricultural lands, providing ideal conditions of temperature and humidity for short-term plant growing, thereby increasing the local production of fruit and vegetables. This paper presents the development of a durable greenhouse concept that is based on complex energy system integrating fuel cells and solar panels. Approaching this innovative concept encountered a major problem in terms of local implementation of this type of greenhouses because of the difficulty in providing electrical and thermal energy from conventional sources to ensure an optimal climate for plant growing. The project result consists in the design and implementation of a sustainable greenhouse energy system that is based on fuel cells and solar panels.

Modulating Function-Based Method for Parameter and Source Estimation of Partial Differential Equations

KAUST Repository

Asiri, Sharefa M.

2017-10-08

Partial Differential Equations (PDEs) are commonly used to model complex systems that arise for example in biology, engineering, chemistry, and elsewhere. The parameters (or coefficients) and the source of PDE models are often unknown and are estimated from available measurements. Despite its importance, solving the estimation problem is mathematically and numerically challenging and especially when the measurements are corrupted by noise, which is often the case. Various methods have been proposed to solve estimation problems in PDEs which can be classified into optimization methods and recursive methods. The optimization methods are usually heavy computationally, especially when the number of unknowns is large. In addition, they are sensitive to the initial guess and stop condition, and they suffer from the lack of robustness to noise. Recursive methods, such as observer-based approaches, are limited by their dependence on some structural properties such as observability and identifiability which might be lost when approximating the PDE numerically. Moreover, most of these methods provide asymptotic estimates which might not be useful for control applications for example. An alternative non-asymptotic approach with less computational burden has been proposed in engineering fields based on the so-called modulating functions. In this dissertation, we propose to mathematically and numerically analyze the modulating functions based approaches. We also propose to extend these approaches to different situations. The contributions of this thesis are as follows. (i) Provide a mathematical analysis of the modulating function-based method (MFBM) which includes: its well-posedness, statistical properties, and estimation errors. (ii) Provide a numerical analysis of the MFBM through some estimation problems, and study the sensitivity of the method to the modulating functions\\' parameters. (iii) Propose an effective algorithm for selecting the method\\'s design parameters

PANDORA: keyword-based analysis of protein sets by integration of annotation sources.

Science.gov (United States)

Kaplan, Noam; Vaaknin, Avishay; Linial, Michal

2003-10-01

Recent advances in high-throughput methods and the application of computational tools for automatic classification of proteins have made it possible to carry out large-scale proteomic analyses. Biological analysis and interpretation of sets of proteins is a time-consuming undertaking carried out manually by experts. We have developed PANDORA (Protein ANnotation Diagram ORiented Analysis), a web-based tool that provides an automatic representation of the biological knowledge associated with any set of proteins. PANDORA uses a unique approach of keyword-based graphical analysis that focuses on detecting subsets of proteins that share unique biological properties and the intersections of such sets. PANDORA currently supports SwissProt keywords, NCBI Taxonomy, InterPro entries and the hierarchical classification terms from ENZYME, SCOP and GO databases. The integrated study of several annotation sources simultaneously allows a representation of biological relations of structure, function, cellular location, taxonomy, domains and motifs. PANDORA is also integrated into the ProtoNet system, thus allowing testing thousands of automatically generated clusters. We illustrate how PANDORA enhances the biological understanding of large, non-uniform sets of proteins originating from experimental and computational sources, without the need for prior biological knowledge on individual proteins.

Minimax robust power split in AF relays based on uncertain long-term CSI

KAUST Repository

Nisar, Muhammad Danish

2011-09-01

An optimal power control among source and relay nodes in presence of channel state information (CSI) is vital for an efficient amplify and forward (AF) based cooperative communication system. In this work, we study the optimal power split (power control) between the source and relay node in presence of an uncertainty in the CSI. The prime contribution is to solve the problem based on an uncertain long-term knowledge of both the first and second hop CSI (requiring less frequent updates), and under an aggregate network-level power constraint. We employ the minimax optimization methodology to arrive at the minimax robust optimal power split, that offers the best possible guarantee on the end-to-end signal to noise ratio (SNR). The derived closed form analytical expressions admit simple intuitive interpretations and are easy to implement in real-world AF relaying systems. Numerical results confirm the advantages of incorporating the presence of uncertainty into the optimization problem, and demonstrate the usefulness of the proposed minimax robust optimal power split. © 2011 IEEE.

Source term assessment, containment atmosphere control systems, and accident consequences. Report to CSNI by an OECD/NEA Group of experts

International Nuclear Information System (INIS)

1987-04-01

CSNI Report 135 summarizes the results of the work performed by CSNI's Principal Working Group No. 4 on the Source Term and Environmental Consequences (PWG4) during the period extending from 1983 to 1986. This document contains the latest information on some important topics relating to source terms, accident consequence assessment, and containment atmospheric control systems. It consists of five parts: (1) a Foreword and Executive Summary prepared by PWG4's Chairman; (2) a Report on the Technical Status of the Source Term; (3) a Report on the Technical Status of Filtration and Containment Atmosphere Control Systems for Nuclear Reactors in the Event of a Severe Accident; (4) a Report on the Technical Status of Reactor Accident Consequence Assessment; (5) a list of members of PWG4

A New Wave Equation Based Source Location Method with Full-waveform Inversion

KAUST Repository

Wu, Zedong; Alkhalifah, Tariq Ali

2017-01-01

with illumination artifacts. We develop a waveform inversion approach with an additional penalty term in the objective function to reward the focusing of the source image. This penalty term is relaxed early to allow for data fitting, and avoid cycle skipping, using

The SSI TOOLBOX Source Term Model SOSIM - Screening for important radionuclides and parameter sensitivity analysis

Energy Technology Data Exchange (ETDEWEB)

Avila Moreno, R.; Barrdahl, R.; Haegg, C.

1995-05-01

The main objective of the present study was to carry out a screening and a sensitivity analysis of the SSI TOOLBOX source term model SOSIM. This model is a part of the SSI TOOLBOX for radiological impact assessment of the Swedish disposal concept for high-level waste KBS-3. The outputs of interest for this purpose were: the total released fraction, the time of total release, the time and value of maximum release rate, the dose rates after direct releases of the biosphere. The source term equations were derived and simple equations and methods were proposed for calculation of these. A literature survey has been performed in order to determine a characteristic variation range and a nominal value for each model parameter. In order to reduce the model uncertainties the authors recommend a change in the initial boundary condition for solution of the diffusion equation for highly soluble nuclides. 13 refs.

Basic repository source term and data sheet report, Cypress Creek Dome: Draft

International Nuclear Information System (INIS)

1988-01-01

This report is one of a series describing studies undertaken in support of the US Department of Energy Civilian Radioactive Waste Management (CRWM) Program. This study contains the derivation of values for environmental source terms and resources consumed for a CRWM repository. Estimates include heavy construction equipment; support equipment; shaft-sinking equipment; transportation equipment; and consumption of fuel, water, electricity, and natural gas. Data are presented for construction and operation at an assumed site in Cypress Creek Dome, Mississippi. 2 refs., 6 tabs

Optimization method for identifying the source term in an inverse wave equation

Directory of Open Access Journals (Sweden)

Arumugam Deiveegan

2017-08-01

Full Text Available In this work, we investigate the inverse problem of identifying a space-wise dependent source term of wave equation from the measurement on the boundary. On the basis of the optimal control framework, the inverse problem is transformed into an optimization problem. The existence and necessary condition of the minimizer for the cost functional are obtained. The projected gradient method and two-parameter model function method are applied to the minimization problem and numerical results are illustrated.

The MIT/OSO 7 catalog of X-ray sources - Intensities, spectra, and long-term variability

Science.gov (United States)

Markert, T. H.; Laird, F. N.; Clark, G. W.; Hearn, D. R.; Sprott, G. F.; Li, F. K.; Bradt, H. V.; Lewin, W. H. G.; Schnopper, H. W.; Winkler, P. F.

1979-01-01

This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1-40-keV X-ray detectors on OSO 7 between October 1971 and May 1973. Specifically, mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3-10-keV range are computed. For those sources for which a statistically significant (greater than 20) intensity was found in the 3-10-keV band (138 sources), further intensity determinations were made in the 1-15-keV, 1-6-keV, and 15-40-keV energy bands. Graphs and other simple techniques are provided to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Long-term light curves (counting rates in one or more energy bands as a function of time) are plotted for 86 of the brighter sources.

Hiding the Source Based on Limited Flooding for Sensor Networks

Directory of Open Access Journals (Sweden)

Juan Chen

2015-11-01

Full Text Available Wireless sensor networks are widely used to monitor valuable objects such as rare animals or armies. Once an object is detected, the source, i.e., the sensor nearest to the object, generates and periodically sends a packet about the object to the base station. Since attackers can capture the object by localizing the source, many protocols have been proposed to protect source location. Instead of transmitting the packet to the base station directly, typical source location protection protocols first transmit packets randomly for a few hops to a phantom location, and then forward the packets to the base station. The problem with these protocols is that the generated phantom locations are usually not only near the true source but also close to each other. As a result, attackers can easily trace a route back to the source from the phantom locations. To address the above problem, we propose a new protocol for source location protection based on limited flooding, named SLP. Compared with existing protocols, SLP can generate phantom locations that are not only far away from the source, but also widely distributed. It improves source location security significantly with low communication cost. We further propose a protocol, namely SLP-E, to protect source location against more powerful attackers with wider fields of vision. The performance of our SLP and SLP-E are validated by both theoretical analysis and simulation results.

Short-Term Fuzzy Load Forecasting Model Using Genetic–Fuzzy and Ant Colony–Fuzzy Knowledge Base Optimization

Directory of Open Access Journals (Sweden)

Murat Luy

2018-05-01

Full Text Available The estimation of hourly electricity load consumption is highly important for planning short-term supply–demand equilibrium in sources and facilities. Studies of short-term load forecasting in the literature are categorized into two groups: classical conventional and artificial intelligence-based methods. Artificial intelligence-based models, especially when using fuzzy logic techniques, have more accurate load estimations when datasets include high uncertainty. However, as the knowledge base—which is defined by expert insights and decisions—gets larger, the load forecasting performance decreases. This study handles the problem that is caused by the growing knowledge base, and improves the load forecasting performance of fuzzy models through nature-inspired methods. The proposed models have been optimized by using ant colony optimization and genetic algorithm (GA techniques. The training and testing processes of the proposed systems were performed on historical hourly load consumption and temperature data collected between 2011 and 2014. The results show that the proposed models can sufficiently improve the performance of hourly short-term load forecasting. The mean absolute percentage error (MAPE of the monthly minimum in the forecasting model, in terms of the forecasting accuracy, is 3.9% (February 2014. The results show that the proposed methods make it possible to work with large-scale rule bases in a more flexible estimation environment.

Toward a Mechanistic Source Term in Advanced Reactors: Characterization of Radionuclide Transport and Retention in a Sodium Cooled Fast Reactor

Energy Technology Data Exchange (ETDEWEB)

Brunett, Acacia J.; Bucknor, Matthew; Grabaskas, David

2016-04-17

A vital component of the U.S. reactor licensing process is an integrated safety analysis in which a source term representing the release of radionuclides during normal operation and accident sequences is analyzed. Historically, source term analyses have utilized bounding, deterministic assumptions regarding radionuclide release. However, advancements in technical capabilities and the knowledge state have enabled the development of more realistic and best-estimate retention and release models such that a mechanistic source term assessment can be expected to be a required component of future licensing of advanced reactors. Recently, as part of a Regulatory Technology Development Plan effort for sodium cooled fast reactors (SFRs), Argonne National Laboratory has investigated the current state of knowledge of potential source terms in an SFR via an extensive review of previous domestic experiments, accidents, and operation. As part of this work, the significant sources and transport processes of radionuclides in an SFR have been identified and characterized. This effort examines all stages of release and source term evolution, beginning with release from the fuel pin and ending with retention in containment. Radionuclide sources considered in this effort include releases originating both in-vessel (e.g. in-core fuel, primary sodium, cover gas cleanup system, etc.) and ex-vessel (e.g. spent fuel storage, handling, and movement). Releases resulting from a primary sodium fire are also considered as a potential source. For each release group, dominant transport phenomena are identified and qualitatively discussed. The key product of this effort was the development of concise, inclusive diagrams that illustrate the release and retention mechanisms at a high level, where unique schematics have been developed for in-vessel, ex-vessel and sodium fire releases. This review effort has also found that despite the substantial range of phenomena affecting radionuclide release, the

Effect of hypoiodous acid volatility on the iodine source term in reactor accidents

Energy Technology Data Exchange (ETDEWEB)

Routamo, T [Imatran Voima Oy, Vantaa (Finland)

1996-12-01

A FORTRAN code ACT WATCH has been developed to establish an improved understanding of essential radionuclide behaviour mechanisms, especially related to iodine chemistry, in reactor accidents. The accident scenarios calculated in this paper are based on the Loss of Coolant accident at the Loviisa Nuclear Power Plant. The effect of different airborne species, especially HIO, on the iodine source term has been studied. The main cause of the high HIO release in the system modelled is the increase of I{sub 2} hydrolysis rate along with the temperature increase, which accelerates HIO production. Due to the high radiation level near the reactor core, I{sub 2} is produced from I{sup -}very rapidly. High temperature in the reactor coolant causes I{sub 2} to be transformed into HIO and through the boiling of the coolant volatile I{sub 2} and HIO are transferred efficiently into the gas phase. High filtration efficiency for particulate iodine causes I{sup -} release to be much lower than those of I{sub 2} and HIO. (author) 15 figs., 1 tab., refs.

Effect of hypoiodous acid volatility on the iodine source term in reactor accidents

International Nuclear Information System (INIS)

Routamo, T.

1996-01-01

A FORTRAN code ACT WATCH has been developed to establish an improved understanding of essential radionuclide behaviour mechanisms, especially related to iodine chemistry, in reactor accidents. The accident scenarios calculated in this paper are based on the Loss of Coolant accident at the Loviisa Nuclear Power Plant. The effect of different airborne species, especially HIO, on the iodine source term has been studied. The main cause of the high HIO release in the system modelled is the increase of I 2 hydrolysis rate along with the temperature increase, which accelerates HIO production. Due to the high radiation level near the reactor core, I 2 is produced from I - very rapidly. High temperature in the reactor coolant causes I 2 to be transformed into HIO and through the boiling of the coolant volatile I 2 and HIO are transferred efficiently into the gas phase. High filtration efficiency for particulate iodine causes I - release to be much lower than those of I 2 and HIO. (author) 15 figs., 1 tab., refs

Refined Source Terms in WAVEWATCH III with Wave Breaking and Sea Spray Forecasts

Science.gov (United States)

2015-09-30

dissipation and breaking, nonlinear wave-wave interaction, bottom friction, wave-mud interaction, wave-current interaction as well as sea spray flux. These...shallow water outside the surf zone. After careful testing within a comprehensive suite of test bed cases, these refined source terms will be...aim to refine the parameterization of air-sea and upper ocean fluxes, including wind input and sea spray as well as dissipation, and hence improve

Real-time software for multi-isotopic source term estimation

International Nuclear Information System (INIS)

Goloubenkov, A.; Borodin, R.; Sohier, A.

1996-01-01

Consideration is given to development of software for one of crucial components of the RODOS - assessment of the source rate (SR) from indirect measurements. Four components of the software are described in the paper. First component is a GRID system, which allow to prepare stochastic meteorological and radioactivity fields using measured data. Second part is a model of atmospheric transport which can be adapted for emulation of practically any gamma dose/spectrum detectors. The third one is a method which allows space-time and quantitative discrepancies in measured and modelled data to be taken into account simultaneously. It bases on the preference scheme selected by an expert. Last component is a special optimization method for calculation of multi-isotopic SR and its uncertainties. Results of a validation of the software using tracer experiments data and Chernobyl source estimation for main dose-forming isotopes are enclosed in the paper

Running the source term code package in Elebra MX-850

International Nuclear Information System (INIS)

Guimaraes, A.C.F.; Goes, A.G.A.

1988-01-01

The source term package (STCP) is one of the main tools applied in calculations of behavior of fission products from nuclear power plants. It is a set of computer codes to assist the calculations of the radioactive materials leaving from the metallic containment of power reactors to the environment during a severe reactor accident. The original version of STCP runs in SDC computer systems, but as it has been written in FORTRAN 77, is possible run it in others systems such as IBM, Burroughs, Elebra, etc. The Elebra MX-8500 version of STCP contains 5 codes:March 3, Trapmelt, Tcca, Vanessa and Nava. The example presented in this report has taken into consideration a small LOCA accident into a PWR type reactor. (M.I.)

BioPortal: An Open-Source Community-Based Ontology Repository

Science.gov (United States)

Noy, N.; NCBO Team

2011-12-01

Advances in computing power and new computational techniques have changed the way researchers approach science. In many fields, one of the most fruitful approaches has been to use semantically aware software to break down the barriers among disparate domains, systems, data sources, and technologies. Such software facilitates data aggregation, improves search, and ultimately allows the detection of new associations that were previously not detectable. Achieving these analyses requires software systems that take advantage of the semantics and that can intelligently negotiate domains and knowledge sources, identifying commonality across systems that use different and conflicting vocabularies, while understanding apparent differences that may be concealed by the use of superficially similar terms. An ontology, a semantically rich vocabulary for a domain of interest, is the cornerstone of software for bridging systems, domains, and resources. However, as ontologies become the foundation of all semantic technologies in e-science, we must develop an infrastructure for sharing ontologies, finding and evaluating them, integrating and mapping among them, and using ontologies in applications that help scientists process their data. BioPortal [1] is an open-source on-line community-based ontology repository that has been used as a critical component of semantic infrastructure in several domains, including biomedicine and bio-geochemical data. BioPortal, uses the social approaches in the Web 2.0 style to bring structure and order to the collection of biomedical ontologies. It enables users to provide and discuss a wide array of knowledge components, from submitting the ontologies themselves, to commenting on and discussing classes in the ontologies, to reviewing ontologies in the context of their own ontology-based projects, to creating mappings between overlapping ontologies and discussing and critiquing the mappings. Critically, it provides web-service access to all its

Source terms associated with two severe accident sequences in a 900 MWe PWR

International Nuclear Information System (INIS)

Fermandjian, J.; Evrard, J.M.; Berthion, Y.; Lhiaubet, G.; Lucas, M.

1983-12-01

Hypothetical accidents taken into account in PWR risk assessment result in fission product release from the fuel, transfer through the primary circuit, transfer into the reactor containment building (RCB) and finally release to the environment. The objective of this paper is to define the characteristics of the source term (noble gases, particles and volatile iodine forms) released from the reactor containment building during two dominant core-melt accident sequences: S 2 CD and TLB according to the ''Reactor Safety Study'' terminology. The reactor chosen for this study is a French 900 MWe PWR unit. The reactor building is a prestressed concrete containment with an internal liner. The first core-melt accident sequence is a 2-break loss-of-coolant accident on the cold leg, with failure of both system and the containment spray system. The second one is a transient initiated by a loss of offsite and onsite power supply and auxiliary feedwater system. These two sequences have been chosen because they are representative of risk dominant scenarios. Source terms associated with hypothetical core-melt accidents S 2 CD and TLB in a French PWR -900 MWe- have been performed using French computer codes (in particular, JERICHO Code for containment response analysis and AEROSOLS/31 for aerosol behavior in the containment)

Long-term monitoring of molecular markers can distinguish different seasonal patterns of fecal indicating bacteria sources.

Science.gov (United States)

Riedel, Timothy E; Thulsiraj, Vanessa; Zimmer-Faust, Amity G; Dagit, Rosi; Krug, Jenna; Hanley, Kaitlyn T; Adamek, Krista; Ebentier, Darcy L; Torres, Robert; Cobian, Uriel; Peterson, Sophie; Jay, Jennifer A

2015-03-15

Elevated levels of fecal indicator bacteria (FIB) have been observed at Topanga Beach, CA, USA. To identify the FIB sources, a microbial source tracking study using a dog-, a gull- and two human-associated molecular markers was conducted at 10 sites over 21 months. Historical data suggest that episodic discharge from the lagoon at the mouth of Topanga Creek is the main source of bacteria to the beach. A decline in creek FIB/markers downstream from upper watershed development and a sharp increase in FIB/markers at the lagoon sites suggest sources are local to the lagoon. At the lagoon and beach, human markers are detected sporadically, dog marker peaks in abundance mid-winter, and gull marker is chronically elevated. Varied seasonal patterns of FIB and source markers were identified showing the importance of applying a suite of markers over long-term spatial and temporal sampling to identify a complex combination of sources of contamination. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Source Anonymity-Based Lightweight Secure AODV Protocol for Fog-Based MANET.

Science.gov (United States)

Fang, Weidong; Zhang, Wuxiong; Xiao, Jinchao; Yang, Yang; Chen, Wei

2017-06-17

Fog-based MANET (Mobile Ad hoc networks) is a novel paradigm of a mobile ad hoc network with the advantages of both mobility and fog computing. Meanwhile, as traditional routing protocol, ad hoc on-demand distance vector (AODV) routing protocol has been applied widely in fog-based MANET. Currently, how to improve the transmission performance and enhance security are the two major aspects in AODV's research field. However, the researches on joint energy efficiency and security seem to be seldom considered. In this paper, we propose a source anonymity-based lightweight secure AODV (SAL-SAODV) routing protocol to meet the above requirements. In SAL-SAODV protocol, source anonymous and secure transmitting schemes are proposed and applied. The scheme involves the following three parts: the source anonymity algorithm is employed to achieve the source node, without being tracked and located; the improved secure scheme based on the polynomial of CRC-4 is applied to substitute the RSA digital signature of SAODV and guarantee the data integrity, in addition to reducing the computation and energy consumption; the random delayed transmitting scheme (RDTM) is implemented to separate the check code and transmitted data, and achieve tamper-proof results. The simulation results show that the comprehensive performance of the proposed SAL-SAODV is a trade-off of the transmission performance, energy efficiency, and security, and better than AODV and SAODV.

Description of apparatus for determining radiological source terms of nuclear fuels

International Nuclear Information System (INIS)

Baldwin, D.L.; Woodley, R.E.; Holt, F.E.; Archer, D.V.; Steele, R.T.; Whitkop, P.G.

1985-01-01

New apparatus have been designed, built and are currently being employed to measure the release of volatile fission products from irradiated nuclear fuel. The system is capable of measuring radiological source terms, particularly for cesium-137, cesium-134, iodine-129 and krypton-85, in various atmospheres at temperatures up to 1200 0 C. The design allows a rapid transient heatup from ambient to full temperature, a hold at maximum temperature for a specified period, and rapid cooldown. Released fission products are measured as deposition on a platinum thermal gradient tube or in a filter/charcoal trap. Noble gases pass through to a multi-channel gamma analyzer. 1 ref., 4 figs

Nonlinear estimation-based dipole source localization for artificial lateral line systems

International Nuclear Information System (INIS)

Abdulsadda, Ahmad T; Tan Xiaobo

2013-01-01

As a flow-sensing organ, the lateral line system plays an important role in various behaviors of fish. An engineering equivalent of a biological lateral line is of great interest to the navigation and control of underwater robots and vehicles. A vibrating sphere, also known as a dipole source, can emulate the rhythmic movement of fins and body appendages, and has been widely used as a stimulus in the study of biological lateral lines. Dipole source localization has also become a benchmark problem in the development of artificial lateral lines. In this paper we present two novel iterative schemes, referred to as Gauss–Newton (GN) and Newton–Raphson (NR) algorithms, for simultaneously localizing a dipole source and estimating its vibration amplitude and orientation, based on the analytical model for a dipole-generated flow field. The performance of the GN and NR methods is first confirmed with simulation results and the Cramer–Rao bound (CRB) analysis. Experiments are further conducted on an artificial lateral line prototype, consisting of six millimeter-scale ionic polymer–metal composite sensors with intra-sensor spacing optimized with CRB analysis. Consistent with simulation results, the experimental results show that both GN and NR schemes are able to simultaneously estimate the source location, vibration amplitude and orientation with comparable precision. Specifically, the maximum localization error is less than 5% of the body length (BL) when the source is within the distance of one BL. Experimental results have also shown that the proposed schemes are superior to the beamforming method, one of the most competitive approaches reported in literature, in terms of accuracy and computational efficiency. (paper)

Solution to the inversely stated transient source-receptor problem

International Nuclear Information System (INIS)

Sajo, E.; Sheff, J.R.

1995-01-01

Transient source-receptor problems are traditionally handled via the Boltzmann equation or through one of its variants. In the atmospheric transport of pollutants, meteorological uncertainties in the planetary boundary layer render only a few approximations to the Boltzmann equation useful. Often, due to the high number of unknowns, the atmospheric source-receptor problem is ill-posed. Moreover, models to estimate downwind concentration invariably assume that the source term is known. In this paper, an inverse methodology is developed, based on downwind measurement of concentration and that of meterological parameters to estimate the source term

An ion source upgrade for an axial injection based commercial cyclotron

International Nuclear Information System (INIS)

Dehnel, M.P.; Stewart, T.; Roeder, M.; Le Du, K.

2005-01-01

The TRIUMF H - volume-cusp ion source technology licensed by Dehnel Consulting Ltd ranges in output current from 1 to 15 mA with beam energies in the 22-30 keV range. For those Cyclone 30 cyclotrons installed with an early 1980's style Lawrence Berkeley Lab (LBL) volume-cusp ion source, an upgrade to a 5 mA TRIUMF H - volume-cusp ion source would pay dividends in terms of longer filament, filament post and ion source lens lifetime, as well as less eroded material build-up in the source. In addition, the 5 mA ion source would approximately double the beam current available to inject into the cyclotron while reducing the emittance by about a factor of four. The new system has the potential to significantly boost radioisotope production at Cyclone 30 facilities utilizing the older style LBL ion source

Analysis of the primary source term for meltdown accidents using MELCOR 1.8.2

International Nuclear Information System (INIS)

Schmuck, P.

1995-01-01

The MELCOR code describing accident phenomena in the core and primary systems was used for source term calculations and - in the context of the MELCOR Cooperative Assessment Programme - for studying two-phase flows through components such as valves and chokes. Results of the latter studies in comparison to experiments gave hints for an improved calculation of momentum transfer between the phases. (orig.)

An Organizational-Technical Concept to Deal with Open Source Software License Terms

Directory of Open Access Journals (Sweden)

Sergius Dyck

2016-06-01

Full Text Available Open source software (OSS released under various license terms is widely used as third party libraries in today's software projects. To ensure open source compliance within an organization, a strategic approach to OSS management is needed. As basis for such an approach, we introduce an organizational-technical concept for dealing with the various OSS licenses by using procedural instructions and build automation software. The concept includes the careful consideration of OSS license conditions. The results obtained from this consideration and additional necessary commitments are documented in a so-called license playbook. We introduce procedure instructions enabling a consistent approach for software development using OSS libraries. The procedure instructions are described in a way such that they can be implemented for example for Java projects using the popular build automation tool Apache Maven and the software repository tool Nexus. We give guidance on how to realize such an implementation on basis of automation tools in practice.

Source term experiments project (STEP): aerosol characterization system

International Nuclear Information System (INIS)

Schlenger, B.J.; Dunn, P.F.

1985-01-01

A series of four experiments has been conducted at Argonne National Laboratory's TREAT Reactor. These experiments, which are sponsored by an international consortium organized by the Electric Power Research Institute, are designed to investigate the source term, i.e., the type, quantity and timing of release of radioactive fission products from a light water reactor to the environment in the event of a severe accident in which the core is insufficiently cooled. The STEP tests have been designed to provide some of the necessary data regarding the magnitude and release rates of volatile fission products from degraded fuel pins, their physical and chemical characteristics, and aerosol formation and transport phenomena of those fission products that condense to form particles in the cooler regions of the reactor beyond the core. These are inpile experiments, whereby the test fuels are heated in a nuclear test reactor by neutron induced fission and subsequent cladding oxidation in steam environments that simulate as closely as practical predicted severe reactor accident conditions. The test sequences cover a range of pressure and fuel heatup rate, and include the effect of Ag/In/Cd control rod material. 1 ref., 8 figs., 1 tab

Coming to Terms: A conflict analysis of the usage, in official and unofficial sources, of 'security fence', 'apartheid wall', and other terms for the structure between Israel and the Palestinian Territories

NARCIS (Netherlands)

Rogers, R.A.; Ben-David, A.

2010-01-01

The official terms for the dividing wall are ‘security fence’ on the Israeli side and ‘apartheid wall’ on the Palestinian side. Both terms fuse two contextually charged notions to describe the construction project. Beyond the two official terms, the structure has been given other names by sources

Open-source hardware for medical devices.

Science.gov (United States)

Niezen, Gerrit; Eslambolchilar, Parisa; Thimbleby, Harold

2016-04-01

Open-source hardware is hardware whose design is made publicly available so anyone can study, modify, distribute, make and sell the design or the hardware based on that design. Some open-source hardware projects can potentially be used as active medical devices. The open-source approach offers a unique combination of advantages, including reducing costs and faster innovation. This article compares 10 of open-source healthcare projects in terms of how easy it is to obtain the required components and build the device.

135Cs/137Cs isotopic composition of environmental samples across Europe: Environmental transport and source term emission applications

International Nuclear Information System (INIS)

Snow, Mathew S.; Snyder, Darin C.

2016-01-01

135 Cs/ 137 Cs isotopic analyses represent an important tool for studying the fate and transport of radiocesium in the environment; in this work the 135 Cs/ 137 Cs isotopic composition in environmental samples taken from across Europe is reported. Surface soil and vegetation samples from western Russia, Ukraine, Austria, and Hungary show consistent aged thermal fission product 135 Cs/ 137 Cs isotope ratios of 0.58 ± 0.01 (age corrected to 1/1/15), with the exception of one sample of soil-moss from Hungary which shows an elevated 135 Cs/ 137 Cs ratio of 1.78 ± 0.12. With the exception of the outlier sample from Hungary, surface soil/vegetation data are in quantitative agreement with values previously reported for soils within the Chernobyl exclusion zone, suggesting that radiocesium at these locations is primarily composed of homogenous airborne deposition from Chernobyl. Seawater samples taken from the Irish Sea show 135 Cs/ 137 Cs isotope ratios of 1.22 ± 0.11 (age corrected to 1/1/15), suggesting aged thermal fission product Cs discharged from Sellafield. The differences in 135 Cs/ 137 Cs isotope ratios between Sellafield, Chernobyl, and global nuclear weapons testing fallout indicate that 135 Cs/ 137 Cs isotope ratios can be utilized to discriminate between and track radiocesium transport from different nuclear production source terms, including major emission sources in Europe. - Highlights: • 135 Cs/ 137 Cs useful for tracking anthropogenic environmental radiocesium releases. • European surface soils/vegetation have uniform ratio consistent with Chernobyl. • 135 Cs/ 137 Cs in Irish sea represents thermal fission ratio distinct from Chernobyl. • Can distinguish between major source terms in Europe based on 135 Cs/ 137 Cs.

ITER task title - source term data, modelling, and analysis. ITER subtask no. S81TT05/5 (SEP 1-1). Global tritium source term analysis basis document. Subtask 1: operational tritium effluents and releases. Final report (1995 TASK)

International Nuclear Information System (INIS)

Kalyanam, K.M.

1996-06-01

This document represents the final report for the global tritium source term analysis task initiated in 1995. The report presents a room-by-room map/table at the subsystem level for the ITER tritium systems, identifying the major equipment, secondary containments, tritium release sources, duration/frequency of tritium releases and the release pathways. The chronic tritium releases during normal operation, as well as tritium releases due to routine maintenance of the Water Distillation Unit, Isotope Separation System and Primary and Secondary Heat Transport Systems, have been estimated for most of the subsystems, based on the IDR design, the Design Description Documents (April - Jun 1995 issues) and the design updates up to December 1995. The report also outlines the methodology and the key assumptions that are adopted in preparing the tritium release estimates. The design parameters for the ITER Basic Performance Phase (BPP) have been used in estimating the tritium releases shown in the room-by-room map/table. The tritium release calculations and the room-by-room map/table have been prepared in EXCEL, so that the estimates can be refined easily as the design evolves and more detailed information becomes available. (author). 23 refs., tabs

Short-Term Memory Stages in Sign vs. Speech: The Source of the Serial Span Discrepancy

Science.gov (United States)

Hall, Matthew L.; Bavelier, Daphne

2011-01-01

Speakers generally outperform signers when asked to recall a list of unrelated verbal items. This phenomenon is well established, but its source has remained unclear. In this study, we evaluate the relative contribution of the three main processing stages of short-term memory--perception, encoding, and recall--in this effect. The present study…

A critical assessment of flux and source term closures in shallow water models with porosity for urban flood simulations

Science.gov (United States)

Guinot, Vincent

2017-11-01

The validity of flux and source term formulae used in shallow water models with porosity for urban flood simulations is assessed by solving the two-dimensional shallow water equations over computational domains representing periodic building layouts. The models under assessment are the Single Porosity (SP), the Integral Porosity (IP) and the Dual Integral Porosity (DIP) models. 9 different geometries are considered. 18 two-dimensional initial value problems and 6 two-dimensional boundary value problems are defined. This results in a set of 96 fine grid simulations. Analysing the simulation results leads to the following conclusions: (i) the DIP flux and source term models outperform those of the SP and IP models when the Riemann problem is aligned with the main street directions, (ii) all models give erroneous flux closures when is the Riemann problem is not aligned with one of the main street directions or when the main street directions are not orthogonal, (iii) the solution of the Riemann problem is self-similar in space-time when the street directions are orthogonal and the Riemann problem is aligned with one of them, (iv) a momentum balance confirms the existence of the transient momentum dissipation model presented in the DIP model, (v) none of the source term models presented so far in the literature allows all flow configurations to be accounted for(vi) future laboratory experiments aiming at the validation of flux and source term closures should focus on the high-resolution, two-dimensional monitoring of both water depth and flow velocity fields.

Unclassified Source Term and Radionuclide Data for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, Revision 1

Energy Technology Data Exchange (ETDEWEB)

Peter Martian

2009-05-01

This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for CAU 97: Yucca Flat/Climax Mine. The total residual inventory of radionuclides associated with one or more tests is known as the radiologic source term (RST). The RST is comprised of radionuclides in water, glass, or other phases or mineralogic forms. The hydrologic source term (HST) of an underground nuclear test is the portion of the total RST that is released into the groundwater over time following the test. In this report, the HST represents radionuclide release some time after the explosion and does not include the rapidly evolving mechanical, thermal, and chemical processes during the explosion. The CAU 97: Yucca Flat/Climax Mine has many more detonations and a wider variety of settings to consider compared to other CAUs. For instance, the source term analysis and evaluation performed for CAUs 101 and 102: Central and Western Pahute Mesa and CAU 98: Frenchman Flat did not consider vadose zone attenuation because many detonations were located near or below the water table. However, the large number of Yucca Flat/Climax Mine tests and the location of many tests above the water table warrant a more robust analysis of the unsaturated zone.

Accelerator based neutron source for neutron capture therapy

International Nuclear Information System (INIS)

Salimov, R.; Bayanov, B.; Belchenko, Yu.; Belov, V.; Davydenko, V.; Donin, A.; Dranichnikov, A.; Ivanov, A.; Kandaurov, I; Kraynov, G.; Krivenko, A.; Kudryavtsev, A.; Kursanov, N.; Savkin, V.; Shirokov, V.; Sorokin, I.; Taskaev, S.; Tiunov, M.

2004-01-01

Full text: The Budker Institute of Nuclear Physics (Novosibirsk) and the Institute of Physics and Power Engineering (Obninsk) have proposed an accelerator based neutron source for neutron capture and fast neutron therapy for hospital. Innovative approach is based upon vacuum insulation tandem accelerator (VITA) and near threshold 7 Li(p,n) 7 Be neutron generation. Pilot accelerator based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. In the present report, the pilot facility design is presented and discussed. Design features of facility components are discussed. Results of experiments and simulations are presented. Complete experimental tests are planned by the end of the year 2005

MR-based source localization for MR-guided HDR brachytherapy

Science.gov (United States)

Beld, E.; Moerland, M. A.; Zijlstra, F.; Viergever, M. A.; Lagendijk, J. J. W.; Seevinck, P. R.

2018-04-01

For the purpose of MR-guided high-dose-rate (HDR) brachytherapy, a method for real-time localization of an HDR brachytherapy source was developed, which requires high spatial and temporal resolutions. MR-based localization of an HDR source serves two main aims. First, it enables real-time treatment verification by determination of the HDR source positions during treatment. Second, when using a dummy source, MR-based source localization provides an automatic detection of the source dwell positions after catheter insertion, allowing elimination of the catheter reconstruction procedure. Localization of the HDR source was conducted by simulation of the MR artifacts, followed by a phase correlation localization algorithm applied to the MR images and the simulated images, to determine the position of the HDR source in the MR images. To increase the temporal resolution of the MR acquisition, the spatial resolution was decreased, and a subpixel localization operation was introduced. Furthermore, parallel imaging (sensitivity encoding) was applied to further decrease the MR scan time. The localization method was validated by a comparison with CT, and the accuracy and precision were investigated. The results demonstrated that the described method could be used to determine the HDR source position with a high accuracy (0.4–0.6 mm) and a high precision (⩽0.1 mm), at high temporal resolutions (0.15–1.2 s per slice). This would enable real-time treatment verification as well as an automatic detection of the source dwell positions.

Adiabatic energization in the ring current and its relation to other source and loss terms

Science.gov (United States)

Liemohn, M. W.; Kozyra, J. U.; Clauer, C. R.; Khazanov, G. V.; Thomsen, M. F.

2002-04-01

The influence of adiabatic energization and deenergization effects, caused by particle drift in radial distance, on ring current growth rates and loss lifetimes is investigated. Growth and loss rates from simulation results of four storms (5 June 1991, 15 May 1997, 19 October 1998, and 25 September 1998) are examined and compared against the y component of the solar wind electric field (Ey,sw). Energy change rates with and without the inclusion of adiabatic energy changes are considered to isolate the influence of this mechanism in governing changes of ring current strength. It is found that the influence of adiabatic drift effects on the energy change rates is very large when energization and deenergization are considered separately as gain and loss mechanisms, often about an order of magnitude larger than all other source or loss terms combined. This is true not only during storm times, when the open drift path configuration of the hot ions dominates the physics of the ring current, but also during quiet times, when the small oscillation in L of the closed trajectories creates a large source and loss of energy each drift orbit. However, the net energy change from adiabatic drift is often smaller than other source and loss processes, especially during quiet times. Energization from adiabatic drift dominates ring current growth only during portions of the main phase of storms. Furthermore, the net-adiabatic energization is often positive, because some particles are lost in the inner magnetosphere before they can adiabatically deenergize. It is shown that the inclusion of only this net-adiabatic drift effect in the total source rate or loss lifetime (depending on the sign of the net-adiabatic energization) best matches the observed source and loss values from empirical Dst predictor methods (that is, for consistency, these values should be compared between the calculation methods). While adiabatic deenergization dominates the loss timescales for all Ey,sw values

Six transformer based asymmetrical embedded Z-source inverters

DEFF Research Database (Denmark)

Wei, Mo; Poh Chiang, Loh; Chi, Jin

2013-01-01

Embedded/Asymmetrical embedded Z-source inverters were proposed to maintain smooth input current/voltage across the dc source and within the impedance network, remain the shoot-through feature used to boost up the dc-link voltage without adding bulky filter at input side. This paper introduces a ...... a class of transformer based asymmetrical embedded Z-source inverters which keep the smooth input current and voltage while achieving enhanced voltage boost capability. The presented inverters are verified by laboratory prototypes experimentally....

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

An improvement of estimation method of source term to the environment for interfacing system LOCA for typical PWR using MELCOR code

Energy Technology Data Exchange (ETDEWEB)

Han, Seok Jung; Kim, Tae Woon; Ahn, Kwang Il [Risk and Environmental Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-06-15

Interfacing-system loss-of-coolant-accident (ISLOCA) has been identified as the most hazardous accident scenario in the typical PWR plants. The present study as an effort to improve the knowledge of the source term to the environment during ISLOCA focuses on an improvement of the estimation method. The improvement was performed to take into account an effect of broken pipeline and auxiliary building structures relevant to ISLOCA. An estimation of the source term to the environment was for the OPR-1000 plants by MELOCR code version 1.8.6. The key features of the source term showed that the massive amount of fission products departed from the beginning of core degradation to the vessel breach. The release amount of fission products may be affected by the broken pipeline and the auxiliary building structure associated with release pathway.

Preliminary design of GDT-based 14 MeV neutron source

International Nuclear Information System (INIS)

Du Hongfei; Chen Dehong; Wang Hui; Wang Fuqiong; Jiang Jieqiong; Wu Yican; Chen Yiping

2012-01-01

To meet the need of D-T fusion neutron source for fusion material testing, design goals were presented in this paper according to the international requirements of neutron source for fusion material testing. A preliminary design scheme of GDT-based 14 MeV neutron source was proposed, and a physics model of the neutron source was built based on progress of GDT experiments. Two preliminary design schemes (i. e. FDS-GDT1, FDS-GDT2) were designed; among which FDS-GDT2 can be used for fusion material testing with neutron first wall loading of 2 MW/m 2 . (authors)

Long-term transition to power/hydrogen energy system based on regenerative energy sources. Langfristiger Uebergang zum Strom/Wasserstoff-Energiesystem auf der Basis erneuerbarer Energiequellen

Energy Technology Data Exchange (ETDEWEB)

Wurster, R

1989-01-01

If we mean to secure the future of this planet in its present state we shall have to reduce drastically the emissions of trace gases influencing our climate like CO/sub 2/, CH/sub 4/, FCHC, ozone, N/sub 2/O and stratospheric H/sub 2/O. CO/sub -/neutral energy sources in clude nuclear energy and regenerative energies (solar, wind, water, biomass, tidal energy). These energy sources provide energy carriers in terms of electricity, heat, biofuels, synthesis gas and hydrogen. The author discusses the power/hydrogen energy system, electrolytic generation of hydrogen and its capacity for storage and transport from sunny solar-energy utilization areas (Central Africa). Hydrogen can then be used in drive systems, power generation (power stations) and for space heating and process heat. The author discusses its profitability and underlines the fact that hydrogen will figure in the energy economy of the future. (HWJ).

Short-Term Success versus Long-Term Failure: A Simulation-Based Approach for Understanding the Potential of Zambia’s Fertilizer Subsidy Program in Enhancing Maize Availability

Directory of Open Access Journals (Sweden)

Andreas Gerber

2016-10-01

Full Text Available In Sub-Saharan Africa, food-related policies such as fertilizer subsidy programs (FSPs have undergone a revival and triggered a controversy about their impact. In this article I applied a simulation-based approach to examine the FSPs’ short- and long-term potential for increasing maize availability in Zambia. The study revealed that FSPs are an effective policy measure to enhance maize availability in the short-term. However, in the long-term, the food system becomes dependent on the government’s annual expenses. The dependency occurs because FSPs fail to build up adequate stock levels of soil organic matter (SOM, which is an important source of resilience and productivity, and thus represents a long-term leverage point in Zambia’s maize production system. For this reason, alternative policies that combine increasing productivity and building up SOM stock levels were analyzed. They were found to be a viable means for enhancing long-term maize availability. The study concludes that gradually reducing investments in FSPs while simultaneously promoting farming practices that build up SOM stock levels is a promising strategy to enhance maize availability sustainably.

Hepatocyte transplantation and advancements in alternative cell sources for liver-based regenerative medicine.

Science.gov (United States)

Lee, Charlotte A; Sinha, Siddharth; Fitzpatrick, Emer; Dhawan, Anil

2018-06-01

Human hepatocyte transplantation has been actively perused as an alternative to liver replacement for acute liver failure and liver-based metabolic defects. Current challenges in this field include a limited cell source, reduced cell viability following cryopreservation and poor engraftment of cells into the recipient liver with consequent limited life span. As a result, alternative stem cell sources such as pluripotent stem cells, fibroblasts, hepatic progenitor cells, amniotic epithelial cells and mesenchymal stem/stromal cells (MSCs) can be used to generate induced hepatocyte like cells (HLC) with each technique exhibiting advantages and disadvantages. HLCs may have comparable function to primary human hepatocytes and could offer patient-specific treatment. However, long-term functionality of transplanted HLCs and the potential oncogenic risks of using stem cells have yet to be established. The immunomodulatory effects of MSCs are promising, and multiple clinical trials are investigating their effect in cirrhosis and acute liver failure. Here, we review the current status of hepatocyte transplantation, alternative cell sources to primary human hepatocytes and their potential in liver regeneration. We also describe recent clinical trials using hepatocytes derived from stem cells and their role in improving the phenotype of several liver diseases.

The Sources of Life Chances: Does Education, Class Category, Occupation, or Short-Term Earnings Predict 20-Year Long-Term Earnings?

Directory of Open Access Journals (Sweden)

ChangHwan Kim

2018-03-01

Full Text Available In sociological studies of economic stratification and intergenerational mobility, occupation has long been presumed to reflect lifetime earnings better than do short-term earnings. However, few studies have actually tested this critical assumption. In this study, we investigate the cross-sectional determinants of 20-year accumulated earnings using data that match respondents in the Survey of Income and Program Participation to their longitudinal earnings records based on administrative tax information from 1990 to 2009. Fit statistics of regression models are estimated to assess the predictive power of various proxy variables, including occupation, education, and short-term earnings, on cumulative earnings over the 20-year time period. Contrary to the popular assumption in sociology, our results find that cross-sectional earnings have greater predictive power on long-term earnings than occupation-based class classifications, including three-digit detailed occupations for both men and women. The model based on educational attainment, including field of study, has slightly better fit than models based on one-digit occupation or the Erikson, Goldthorpe, and Portocarero class scheme. We discuss the theoretical implications of these findings for the sociology of stratification and intergenerational mobility.

The source term and waste optimization of molten salt reactors with processing

International Nuclear Information System (INIS)

Gat, U.; Dodds, H.L.

1993-01-01

The source term of a molten salt reactor (MSR) with fuel processing is reduced by the ratio of processing time to refueling time as compared to solid fuel reactors. The reduction, which can be one to two orders of magnitude, is due to removal of the long-lived fission products. The waste from MSRs can be optimized with respect to its chemical composition, concentration, mixture, shape, and size. The actinides and long-lived isotopes can be separated out and returned to the reactor for transmutation. These features make MSRs more acceptable and simpler in operation and handling

Novel Slope Source Term Treatment for Preservation of Quiescent Steady States in Shallow Water Flows

Directory of Open Access Journals (Sweden)

Khawar Rehman

2016-10-01

Full Text Available This paper proposes a robust method for modeling shallow-water flows and near shore tsunami propagation, applicable for both simple and complex geometries with uneven beds. The novel aspect of the model includes the introduction of a new method for slope source terms treatment to preserve quiescent equilibrium over uneven topographies, applicable to both structured and unstructured mesh systems with equal accuracy. Our model is based on the Godunov-type finite volume numerical approximation. Second-order spatial and temporal accuracy is achieved through high resolution gradient reconstruction and the predictor-corrector method, respectively. The approximate Riemann solver of Harten, Lax, and van Leer with contact wave restoration (HLLC is used to compute fluxes. Comparisons of the model’s results with analytical, experimental, and published numerical solutions show that the proposed method is capable of accurately predicting experimental and real-time tsunami propagation/inundation, and dam-break flows over varying topographies.

A Source Term for Wave Attenuation by Sea Ice in WAVEWATCH III (registered trademark): IC4

Science.gov (United States)

2017-06-07

blue and 4 locations in the ice: 1, 2, 5, and 10 km. Notice the steepening of the high frequency face and the shift of the peak to slightly lower...Term for Wave Attenuation by Sea Ice in WAVEWATCH III®: IC4 ClarenCe O. COllins iii W. eriCk rOgers Ocean Dynamics and Prediction Branch Oceanography...Wave model Sea ice Ocean surface waves Arctic Ocean WAVEWATCH III Spectral wave modeling Source terms Wave hindcasting 73-N2K2-07-5 Naval Research

Agent-based power sharing scheme for active hybrid power sources

Science.gov (United States)

Jiang, Zhenhua

The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

Fusion as a source of synthetic fuels

International Nuclear Information System (INIS)

Powell, J.R.; Fillo, J.A.; Steinberg, M.

1981-01-01

In the near-term, coal derived synthetic fuels will be used; but in the long-term, resource depletion and environmental effects will mandate synthetic fuels from inexhaustible sources - fission, fusion, and solar. Of the three sources, fusion appears uniquely suited for the efficient production of hydrogen-based fuels, due to its ability to directly generate very high process temperatures (up to approx. 2000 0 C) for water splitting reactions. Fusion-based water splitting reactions include high temperature electrolysis (HTE) of steam, thermochemical cycles, hybrid electrochemical/thermochemical, and direct thermal decomposition. HTE appears to be the simplest and most efficient process with efficiencies of 50 to 70% (fusion to hydrogen chemical energy), depending on process conditions

Scenarios catalog for the graphical console for analysis of severe accidents visualization of OEs, NAEs and calculation of source term of the NPP-LV

International Nuclear Information System (INIS)

Sandoval V, S.; Mendoza R, M. E.; Tijerina S, F.; Garcia C, T.

2016-09-01

A nuclear power plant is operated at all times within the design criteria of structures, systems and components, and according to the operation technical specifications. For different areas of work of a nuclear power plant is necessary to carry out practices in which is useful to have the prediction of the thermo-hydraulic and radiological progression of scenarios that imply exceeding that design bases, even reaching the damage of the fuel in different degree. During the exercises and drills of the External Plan of Emergency Response, the projection of doses is done to exercise the different tasks of the plan. To make the projection of doses is required to have the radiological source term of the scenario on which is practiced. Because of this, was identified the convenience of having a catalog of scenarios for which the radiological source term was calculated. In 2004, a first version of the catalog was produced for a power of 2027 MW, and in 2011 the catalog was updated for extended power conditions, 2317 MW. Both versions were made using the severe accident simulator MAAP-3B. That catalog consists of a form and an optical storage device. The form contains tables and figures in which the characteristics of the scenario to be practiced are searched and the electronic files of the corresponding radiological source term are located in the storage device. Due to the recent development of the graphical console for analysis of severe accidents, visualization of OEs, NAEs and calculation of the source term for the nuclear power plant of Laguna Verde (NPP-LV) CoGrAAS, the catalog printed was replaced by an electronic catalog for the CoGrAAS. The new catalog retains the philosophy of the previous catalog, constituted by a wide collection of scenarios that involve different circumstances and phenomena, that can be used to practice different tasks during training exercises or simulacrums, and combined with the following advantages: the scenario selection is made from an

Integrating source-language context into phrase-based statistical machine translation

NARCIS (Netherlands)

Haque, R.; Kumar Naskar, S.; Bosch, A.P.J. van den; Way, A.

2011-01-01

The translation features typically used in Phrase-Based Statistical Machine Translation (PB-SMT) model dependencies between the source and target phrases, but not among the phrases in the source language themselves. A swathe of research has demonstrated that integrating source context modelling

A GIS-based time-dependent seismic source modeling of Northern Iran

Science.gov (United States)

Hashemi, Mahdi; Alesheikh, Ali Asghar; Zolfaghari, Mohammad Reza

2017-01-01

The first step in any seismic hazard study is the definition of seismogenic sources and the estimation of magnitude-frequency relationships for each source. There is as yet no standard methodology for source modeling and many researchers have worked on this topic. This study is an effort to define linear and area seismic sources for Northern Iran. The linear or fault sources are developed based on tectonic features and characteristic earthquakes while the area sources are developed based on spatial distribution of small to moderate earthquakes. Time-dependent recurrence relationships are developed for fault sources using renewal approach while time-independent frequency-magnitude relationships are proposed for area sources based on Poisson process. GIS functionalities are used in this study to introduce and incorporate spatial-temporal and geostatistical indices in delineating area seismic sources. The proposed methodology is used to model seismic sources for an area of about 500 by 400 square kilometers around Tehran. Previous researches and reports are studied to compile an earthquake/fault catalog that is as complete as possible. All events are transformed to uniform magnitude scale; duplicate events and dependent shocks are removed. Completeness and time distribution of the compiled catalog is taken into account. The proposed area and linear seismic sources in conjunction with defined recurrence relationships can be used to develop time-dependent probabilistic seismic hazard analysis of Northern Iran.

Meals based on vegetable protein sources (beans and peas) are more satiating than meals based on animal protein sources (veal and pork) - a randomized cross-over meal test study

DEFF Research Database (Denmark)

Kristensen, Marlene Dahlwad; Bendsen, Nathalie Tommerup; Christensen, Sheena M

2016-01-01

BACKGROUND: Recent nutrition recommendations advocate a reduction in protein from animal sources (pork, beef) because of environmental concerns. Instead, protein from vegetable sources (beans, peas) should be increased. However, little is known about the effect of these vegetable protein sources...... on appetite regulation. OBJECTIVE: To examine whether meals based on vegetable protein sources (beans/peas) are comparable to meals based on animal protein sources (veal/pork) regarding meal-induced appetite sensations. DESIGN: In total, 43 healthy, normal-weight, young men completed this randomized, double......-Legume compared to HP-Meat or LP-Legume (pVegetable-based meals (beans/peas) influenced appetite sensations favorably compared to animal-based meals (pork/veal) with similar energy and protein content, but lower fiber content. Interestingly, a vegetable-based meal with low protein content...

Integral migration and source term experiments on cement and bitumen waste forms

International Nuclear Information System (INIS)

Ewart, F.T.; Howse, R.M.; Sharpe, B.M.; Smith, A.J.; Thomason, H.P.; Williams, S.J.; Young, M.

1986-01-01

This is the final report of a programme of research which formed a part of the CEC joint research project into radionuclide migration in the geosphere (MIRAGE). This study addressed the aspects of integral migration and source term. The integral migration experiment simulated, in the laboratory, the intrusion of water into the repository, the leaching of radionuclides from two intermediate level wasteforms and the subsequent migration through the geosphere. The simulation consisted of a source of natural ground water which flowed over a sample of wasteform, at a controlled redox potential, and then through backfill and geological material packed in columns. The two wasteforms used here were cemented waste from the WAK plant at Karlsruhe, W. Germany and bitumenised intermediate concentrates from the Marcoule plant in France. The soluble fission products such as caesium wire rapidly released from the cemented waste but the actinides, and technetium in the reduced state, were retained in the wasteform. The release of all nuclides from the bitumenised waste was very low. (author)

Integral migration and source-term experiments on cement and bitumen waste forms

International Nuclear Information System (INIS)

Ewart, F.T.; Howse, R.M.; Sharpe, B.M.; Smith, A.J.; Thomason, H.P.; Williams, S.J.; Young, M.

1986-01-01

This is the final report of a programme of research which formed a part of the CEC joint research project into radionuclide migration in the geosphere (MIRAGE). This study addressed the aspects of integral migration and source term. The integral migration experiment simulated, in the laboratory, the intrusion of water into the repository, the leaching of radionuclides from two intermediate-level waste-forms and the subsequent migration through the geosphere. The simulation consisted of a source of natural ground water which flowed over a sample of waste-form, at a controlled redox potential, and then through backfill and geological material packed in columns. The two waste forms used here were cemented waste from the WAK plant at Karlsruhe in the Federal Republic of Germany and bitumenized intermediate concentrates from the Marcoule plant in France. The soluble fission products such as caesium were rapidly released from the cemented waste but the actinides, and technetium in the reduced state, were retained in the waste-form. The released of all nuclides from the bitumenized waste was very low

Uncertainty analysis methods for quantification of source terms using a large computer code

International Nuclear Information System (INIS)

Han, Seok Jung

1997-02-01

Quantification of uncertainties in the source term estimations by a large computer code, such as MELCOR and MAAP, is an essential process of the current probabilistic safety assessments (PSAs). The main objectives of the present study are (1) to investigate the applicability of a combined procedure of the response surface method (RSM) based on input determined from a statistical design and the Latin hypercube sampling (LHS) technique for the uncertainty analysis of CsI release fractions under a hypothetical severe accident sequence of a station blackout at Young-Gwang nuclear power plant using MAAP3.0B code as a benchmark problem; and (2) to propose a new measure of uncertainty importance based on the distributional sensitivity analysis. On the basis of the results obtained in the present work, the RSM is recommended to be used as a principal tool for an overall uncertainty analysis in source term quantifications, while using the LHS in the calculations of standardized regression coefficients (SRC) and standardized rank regression coefficients (SRRC) to determine the subset of the most important input parameters in the final screening step and to check the cumulative distribution functions (cdfs) obtained by RSM. Verification of the response surface model for its sufficient accuracy is a prerequisite for the reliability of the final results obtained by the combined procedure proposed in the present work. In the present study a new measure has been developed to utilize the metric distance obtained from cumulative distribution functions (cdfs). The measure has been evaluated for three different cases of distributions in order to assess the characteristics of the measure: The first case and the second are when the distribution is known as analytical distributions and the other case is when the distribution is unknown. The first case is given by symmetry analytical distributions. The second case consists of two asymmetry distributions of which the skewness is non zero

Measuring Modularity in Open Source Code Bases

Directory of Open Access Journals (Sweden)

Roberto Milev

2009-03-01

Full Text Available Modularity of an open source software code base has been associated with growth of the software development community, the incentives for voluntary code contribution, and a reduction in the number of users who take code without contributing back to the community. As a theoretical construct, modularity links OSS to other domains of research, including organization theory, the economics of industry structure, and new product development. However, measuring the modularity of an OSS design has proven difficult, especially for large and complex systems. In this article, we describe some preliminary results of recent research at Carleton University that examines the evolving modularity of large-scale software systems. We describe a measurement method and a new modularity metric for comparing code bases of different size, introduce an open source toolkit that implements this method and metric, and provide an analysis of the evolution of the Apache Tomcat application server as an illustrative example of the insights gained from this approach. Although these results are preliminary, they open the door to further cross-discipline research that quantitatively links the concerns of business managers, entrepreneurs, policy-makers, and open source software developers.

Operational techniques employed for the liquid sodium source term control loops

International Nuclear Information System (INIS)

Chulos, L.E.

1976-01-01

Four Source Term Control Loops (STCLs) have been designed, constructed, and placed into operation at the Hanford Engineering Development Laboratory (HEDL) as part of the Radioactivity Control Technology program. The data obtained are used to determine the corrosion and deposition of LMFBR materials, including corrosion product radionuclides, in a non-isothermal flowing sodium system. The paper discusses operation of the STCL Facilities and, in particular, the methods used for controlling the oxygen content of the liquid sodium. These methods include cold trapping techniques, hot trapping, seeding the cold traps with sodium oxide, and precipitating the oxygen in the cold trap in a controlled manner. Operational problems encountered with the STCL Facilities and the techniques for correcting these problems are also discussed

Synchrotron based spallation neutron source concepts

International Nuclear Information System (INIS)

Cho, Y.

1998-01-01

During the past 20 years, rapid-cycling synchrotrons (RCS) have been used very productively to generate short-pulse thermal neutron beams for neutron scattering research by materials science communities in Japan (KENS), the UK (ISIS) and the US (IPNS). The most powerful source in existence, ISIS in the UK, delivers a 160-kW proton beam to a neutron-generating target. Several recently proposed facilities require proton beams in the MW range to produce intense short-pulse neutron beams. In some proposals, a linear accelerator provides the beam power and an accumulator ring compresses the pulse length to the required ∼ 1 micros. In others, RCS technology provides the bulk of the beam power and compresses the pulse length. Some synchrotron-based proposals achieve the desired beam power by combining two or more synchrotrons of the same energy, and others propose a combination of lower and higher energy synchrotrons. This paper presents the rationale for using RCS technology, and a discussion of the advantages and disadvantages of synchrotron-based spallation sources

Comprehension and Writing Strategy Training Improves Performance on Content-Specific Source-Based Writing Tasks

Science.gov (United States)

Weston-Sementelli, Jennifer L.; Allen, Laura K.; McNamara, Danielle S.

2018-01-01

Source-based essays are evaluated both on the quality of the writing and the content appropriate interpretation and use of source material. Hence, composing a high-quality source-based essay (an essay written based on source material) relies on skills related to both reading (the sources) and writing (the essay) skills. As such, source-based…

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

International Nuclear Information System (INIS)

Sudiyati; Syahrir; Unggul Hartoyo; Nugraha Luhur

2008-01-01

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

Standard Practice for Conducting Irradiations at Accelerator-Based Neutron Sources

CERN Document Server

American Society for Testing and Materials. Philadelphia

1996-01-01

1.1 This practice covers procedures for irradiations at accelerator-based neutron sources. The discussion focuses on two types of sources, namely nearly monoenergetic 14-MeV neutrons from the deuterium-tritium T(d,n) interaction, and broad spectrum neutrons from stopping deuterium beams in thick beryllium or lithium targets. However, most of the recommendations also apply to other types of accelerator-based sources, including spallation neutron sources (1). Interest in spallation sources has increased recently due to their proposed use for transmutation of fission reactor waste (2). 1.2 Many of the experiments conducted using such neutron sources are intended to simulate irradiation in another neutron spectrum, for example, that from a DT fusion reaction. The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. In general, the intent of these simulations is to establish the fundam...

A study of electron density profiles in relation to ionization sources and ground-based radio wave absorption measurements, part 1

Science.gov (United States)

Gnanalingam, S.; Kane, J. A.

1973-01-01

An extensive set of ground-based measurements of the diurnal variation of medium frequency radio wave adsorption and virtual height is analyzed in terms of current understanding of the D- and lower E-region ion production and loss process. When this is done a gross discrepancy arises, the source of which is not known.

A New Spin on Teaching Vocabulary: A Source-Based Approach.

Science.gov (United States)

Nilsen, Alleen Pace; Nilsen, Don L. F.

2003-01-01

Suggests that teachers should try to use a source-based approach to teaching vocabulary. Explains that a source-based approach starts with basic concepts of human languages and then works with lexical and metaphorical extensions of these basic words. Notes that the purpose of this approach is to find groups of words that can be taught as webs and…

Long-term storage life of light source modules by temperature cycling accelerated life test

International Nuclear Information System (INIS)

Sun Ningning; Tan Manqing; Li Ping; Jiao Jian; Guo Xiaofeng; Guo Wentao

2014-01-01

Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG. (semiconductor devices)

Evaluation of severe accident risks: Methodology for the containment, source term, consequence, and risk integration analyses. Volume 1, Revision 1

International Nuclear Information System (INIS)

Gorham, E.D.; Breeding, R.J.; Brown, T.D.; Harper, F.T.; Helton, J.C.; Murfin, W.B.; Hora, S.C.

1993-12-01

NUREG-1150 examines the risk to the public from five nuclear power plants. The NUREG-1150 plant studies are Level III probabilistic risk assessments (PRAs) and, as such, they consist of four analysis components: accident frequency analysis, accident progression analysis, source term analysis, and consequence analysis. This volume summarizes the methods utilized in performing the last three components and the assembly of these analyses into an overall risk assessment. The NUREG-1150 analysis approach is based on the following ideas: (1) general and relatively fast-running models for the individual analysis components, (2) well-defined interfaces between the individual analysis components, (3) use of Monte Carlo techniques together with an efficient sampling procedure to propagate uncertainties, (4) use of expert panels to develop distributions for important phenomenological issues, and (5) automation of the overall analysis. Many features of the new analysis procedures were adopted to facilitate a comprehensive treatment of uncertainty in the complete risk analysis. Uncertainties in the accident frequency, accident progression and source term analyses were included in the overall uncertainty assessment. The uncertainties in the consequence analysis were not included in this assessment. A large effort was devoted to the development of procedures for obtaining expert opinion and the execution of these procedures to quantify parameters and phenomena for which there is large uncertainty and divergent opinions in the reactor safety community

Modelling and simulation the radioactive source-term of fission products in PWR type reactors; Modelagem e simulacao do termo-fonte radioativo de produtos de fissao em reatores nucleares do tipo PWR

Energy Technology Data Exchange (ETDEWEB)

Porfirio, Rogilson Nazare da Silva

1996-07-01

The source-term was defined with the purpose the quantify all radioactive nuclides released the nuclear reactor in the case of accidents. Nowadays the source-term is limited to the coolant of the primary circuit of reactors and may be measured or modelled with computer coders such as the TFP developed in this work. The calculational process is based on the linear chain techniques used in the CINDER-2 code. The TFP code considers forms of fission products release from the fuel pellet: Recoil, Knockout and Migration. The release from the gap to the coolant fluid is determined from the ratio between activity measured in the coolant and calculated activity in the gap. Considered the operational data of SURRY-1 reactor, the TFP code was run to obtain the source=term of this reactor. From the measured activities it was verified the reliability level of the model and the employed computational logic. The accuracy of the calculated quantities were compared to the measured data was considered satisfactory. (author)

Unclassified Sources Term and Radionuclide Data for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, Revision 2

Energy Technology Data Exchange (ETDEWEB)

Peter Martian

2009-08-01

This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for CAU 97: Yucca Flat/Climax Mine. The total residual inventory of radionuclides associated with one or more tests is known as the radiologic source term (RST). The RST is comprised of radionuclides in water, glass, or other phases or mineralogic forms. The hydrologic source term (HST) of an underground nuclear test is the portion of the total RST that is released into the groundwater over time following the test. In this report, the HST represents radionuclide release some time after the explosion and does not include the rapidly evolving mechanical, thermal, and chemical processes during the explosion. The CAU 97: Yucca Flat/Climax Mine has many more detonations and a wider variety of settings to consider compared to other CAUs. For instance, the source term analysis and evaluation performed for CAUs 101 and 102: Central and Western Pahute Mesa and CAU 98: Frenchman Flat did not consider vadose zone attenuation because many detonations were located near or below the water table. However, the large number of Yucca Flat/Climax Mine tests and the location of many tests above the water table warrant a more robust analysis of the unsaturated zone. The purpose of this report is to develop and document conceptual models of the Yucca Flat/Climax Mine HST for use in implementing source terms for the Yucca Flat/Climax Mine models. This document presents future plans to incorporate the radionuclide attenuation mechanisms due to unsaturated/multiphase flow and transport within the Yucca Flat CAU scale modeling. The important processes that influence radionuclide migration for the unsaturated and saturated tests in alluvial, volcanic, and carbonate settings are identified. Many different flow and transport models developed by Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), including original

Accelerator-based neutron source and its future

International Nuclear Information System (INIS)

Kiyanagi, Yoshiaki

2008-01-01

Neutrons are useful tool for the material science and also for the industrial applications. Now, high intensity neutron sources based on MW class big accelerators are under commissioning in Japan, Japan Spallation Neutron Source (JSNS) at J-PARC and in the US, SNS. Such high power neutron sources required the moderators that can be used under high radiation field and also give high neutronic performance. We have been performing experimental and Monte Carlo simulation studies to develop the cold neutron moderator systems for the high power sources since it is becoming important for materials and life science. Hydrogen is the unique candidate at the present stage due to its high resistibility to the radiation. It was indicated the para hydrogen moderator gave a good neutronic performance by experimental results. On the other hand, in the future, low power neutron sources are recognized to be useful to perform sprouting experiments and to promote the neutron science. The moderator systems need a concept different from the high power source. Therefore, we studied neutronic performances of the mesitylene and the methane moderators to get high intensity in a definite area on the moderator surface. Single groove moderators were studied and optimal geometry and the intensity gain were obtained. The mesitylene moderator gave a rather good performance compared to the methane moderator. (author)

An image-based search for pulsars among Fermi unassociated LAT sources

Science.gov (United States)

Frail, D. A.; Ray, P. S.; Mooley, K. P.; Hancock, P.; Burnett, T. H.; Jagannathan, P.; Ferrara, E. C.; Intema, H. T.; de Gasperin, F.; Demorest, P. B.; Stovall, K.; McKinnon, M. M.

2018-03-01

We describe an image-based method that uses two radio criteria, compactness, and spectral index, to identify promising pulsar candidates among Fermi Large Area Telescope (LAT) unassociated sources. These criteria are applied to those radio sources from the Giant Metrewave Radio Telescope all-sky survey at 150 MHz (TGSS ADR1) found within the error ellipses of unassociated sources from the 3FGL catalogue and a preliminary source list based on 7 yr of LAT data. After follow-up interferometric observations to identify extended or variable sources, a list of 16 compact, steep-spectrum candidates is generated. An ongoing search for pulsations in these candidates, in gamma rays and radio, has found 6 ms pulsars and one normal pulsar. A comparison of this method with existing selection criteria based on gamma-ray spectral and variability properties suggests that the pulsar discovery space using Fermi may be larger than previously thought. Radio imaging is a hitherto underutilized source selection method that can be used, as with other multiwavelength techniques, in the search for Fermi pulsars.

Lessons Learned from Characterization, Performance Assessment, and EPA Regulatory Review of the 1996 Actinide Source Term for the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Larson, K.W.; Moore, R.C.; Nowak, E.J.; Papenguth, H.W.; Jow, H.

1999-01-01

The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy (DOE) facility for the permanent disposal of transuranic waste from defense activities. In 1996, the DOE submitted the Title 40 CFR Part 191 Compliance Certification Application for the Waste Isolation Pilot Plant (CCA) to the US Environmental Protection Agency (EPA). The CCA included a probabilistic performance assessment (PA) conducted by Sandia National Laboratories to establish compliance with the quantitative release limits defined in 40 CFR 191.13. An experimental program to collect data relevant to the actinide source term began around 1989, which eventually supported the 1996 CCA PA actinide source term model. The actinide source term provided an estimate of mobile dissolved and colloidal Pu, Am, U, Th, and Np concentrations in their stable oxidation states, and accounted for effects of uncertainty in the chemistry of brines in waste disposal areas. The experimental program and the actinide source term included in the CCA PA underwent EPA review lasting more than 1 year. Experiments were initially conducted to develop data relevant to the wide range of potential future conditions in waste disposal areas. Interim, preliminary performance assessments and actinide source term models provided insight allowing refinement of experiments and models. Expert peer review provided additional feedback and confidence in the evolving experimental program. By 1995, the chemical database and PA predictions of WIPP performance were considered reliable enough to support the decision to add an MgO backfill to waste rooms to control chemical conditions and reduce uncertainty in actinide concentrations, especially for Pu and Am. Important lessons learned through the characterization, PA modeling, and regulatory review of the actinide source term are (1) experimental characterization and PA should evolve together, with neither activity completely dominating the other, (2) the understanding of physical processes

Overview of waste isoltaion safety assessment program and description of source term characterization task at PNL

International Nuclear Information System (INIS)

Bradley, D.

1977-01-01

A project is being conducted to develop and illustrate the methods and obtain the data necessary to assess the safety of long-term disposal of high-level radioactive waste in geologic formations. The methods and data will initially focus on generic geologic isolation systems but will ultimately be applied to the long-term safety assessment of specific candidate sites that are selected in the NWTS Program. The activities of waste isolation safety assessment (WISAP) are divided into six tasks: (1) Safety Assessment Concepts and Methods, (2) Disruptive Event Analysis, (3) Source Characterization, (4) Transport Modeling, (5) Transport Data and (6) Societal Acceptance

Risk based limits for Operational Safety Requirements

International Nuclear Information System (INIS)

Cappucci, A.J. Jr.

1993-01-01

OSR limits are designed to protect the assumptions made in the facility safety analysis in order to preserve the safety envelope during facility operation. Normally, limits are set based on ''worst case conditions'' without regard to the likelihood (frequency) of a credible event occurring. In special cases where the accident analyses are based on ''time at risk'' arguments, it may be desirable to control the time at which the facility is at risk. A methodology has been developed to use OSR limits to control the source terms and the times these source terms would be available, thus controlling the acceptable risk to a nuclear process facility. The methodology defines a new term ''gram-days''. This term represents the area under a source term (inventory) vs time curve which represents the risk to the facility. Using the concept of gram-days (normalized to one year) allows the use of an accounting scheme to control the risk under the inventory vs time curve. The methodology results in at least three OSR limits: (1) control of the maximum inventory or source term, (2) control of the maximum gram-days for the period based on a source term weighted average, and (3) control of the maximum gram-days at the individual source term levels. Basing OSR limits on risk based safety analysis is feasible, and a basis for development of risk based limits is defensible. However, monitoring inventories and the frequencies required to maintain facility operation within the safety envelope may be complex and time consuming

High power pulsed sources based on fiber amplifiers

Science.gov (United States)

Canat, Guillaume; Jaouën, Yves; Mollier, Jean-Claude; Bouzinac, Jean-Pierre; Cariou, Jean-Pierre

2017-11-01

Cladding-pumped rare-earth-doped fiber laser technologies are currently among the best sources for high power applications. Theses extremely compact and robust sources appoint them as good candidate for aeronautical and space applications. The double-clad (DC) fiber converts the poor beamquality of high-power large-area pump diodes from the 1st cladding to laser light at another wavelength guided in an active single-mode core. High-power coherent MOPA (Master Oscillator Power Amplifier) sources (several 10W CW or several 100W in pulsed regime) will soon be achieved. Unfortunately it also brings nonlinear effects which quickly impairs output signal distortions. Stimulated Brillouin scattering (SBS) and optical parametric amplification (OPA) have been shown to be strong limitations. Based on amplifier modeling and experiments we discuss the performances of these sources.

The Analytical Repository Source-Term (AREST) model: Analysis of spent fuel as a nuclear waste form

International Nuclear Information System (INIS)

Apted, M.J.; Liebetrau, A.M.; Engel, D.W.

1989-02-01

The purpose of this report is to assess the performance of spent fuel as a final waste form. The release of radionuclides from spent nuclear fuel has been simulated for the three repository sites that were nominated for site characterization in accordance with the Nuclear Waste Policy Act of 1982. The simulation is based on waste package designs that were presented in the environmental assessments prepared for each site. Five distinct distributions for containment failure have been considered, and the release for nuclides from the UO 2 matrix, gap (including grain boundary), crud/surface layer, and cladding has been calculated with the Analytic Repository Source-Term (AREST) code. Separate scenarios involving incongruent and congruent release from the UO 2 matrix have also been examined using the AREST code. Congruent release is defined here as the condition in which the relative mass release rates of a given nuclide and uranium from the UO 2 matrix are equal to their mass ratios in the matrix. Incongruent release refers to release of a given nuclide from the UO 2 matrix controlled by its own solubility-limiting solid phase. Release of nuclides from other sources within the spent fuel (e.g., cladding, fuel/cladding gap) is evaluated separately from either incongruent or congruent matrix release. 51 refs., 200 figs., 9 tabs

Numerical simulation of flow induced by a pitched blade turbine. Comparison of the sliding mesh technique and an averaged source term method

Energy Technology Data Exchange (ETDEWEB)

Majander, E.O.J.; Manninen, M.T. [VTT Energy, Espoo (Finland)

1996-12-31

The flow induced by a pitched blade turbine was simulated using the sliding mesh technique. The detailed geometry of the turbine was modelled in a computational mesh rotating with the turbine and the geometry of the reactor including baffles was modelled in a stationary co-ordinate system. Effects of grid density were investigated. Turbulence was modelled by using the standard k-{epsilon} model. Results were compared to experimental observations. Velocity components were found to be in good agreement with the measured values throughout the tank. Averaged source terms were calculated from the sliding mesh simulations in order to investigate the reliability of the source term approach. The flow field in the tank was then simulated in a simple grid using these source terms. Agreement with the results of the sliding mesh simulations was good. Commercial CFD-code FLUENT was used in all simulations. (author)

Numerical simulation of flow induced by a pitched blade turbine. Comparison of the sliding mesh technique and an averaged source term method

Energy Technology Data Exchange (ETDEWEB)

Majander, E O.J.; Manninen, M T [VTT Energy, Espoo (Finland)

1997-12-31

The flow induced by a pitched blade turbine was simulated using the sliding mesh technique. The detailed geometry of the turbine was modelled in a computational mesh rotating with the turbine and the geometry of the reactor including baffles was modelled in a stationary co-ordinate system. Effects of grid density were investigated. Turbulence was modelled by using the standard k-{epsilon} model. Results were compared to experimental observations. Velocity components were found to be in good agreement with the measured values throughout the tank. Averaged source terms were calculated from the sliding mesh simulations in order to investigate the reliability of the source term approach. The flow field in the tank was then simulated in a simple grid using these source terms. Agreement with the results of the sliding mesh simulations was good. Commercial CFD-code FLUENT was used in all simulations. (author)

Source Term Analysis of the Irradiated Graphite in the Core of HTR-10

Directory of Open Access Journals (Sweden)

Xuegang Liu

2017-01-01

Full Text Available The high temperature gas-cooled reactor (HTGR has potential utilization due to its featured characteristics such as inherent safety and wide diversity of utilization. One distinct difference between HTGR and traditional pressurized water reactor (PWR is the large inventory of graphite in the core acting as reflector, moderator, or structure materials. Some radionuclides will be generated in graphite during the period of irradiation, which play significant roles in reactor safety, environmental release, waste disposal, and so forth. Based on the actual operation of the 10 MW pebble bed high temperature gas-cooled reactor (HTR-10 in Tsinghua University, China, an experimental study on source term analysis of the irradiated graphite has been done. An irradiated graphite sphere was randomly collected from the core of HTR-10 as sample in this study. This paper focuses on the analytical procedure and the establishment of the analytical methodology, including the sample collection, graphite sample preparation, and analytical parameters. The results reveal that the Co-60, Cs-137, Eu-152, and Eu-154 are the major γ contributors, while H-3 and C-14 are the dominating β emitting nuclides in postirradiation graphite material of HTR-10. The distribution profiles of the above four nuclides are also presented.

Release of radionuclides following severe accident in interim storage facility. Source term determination

International Nuclear Information System (INIS)

Morandi, S.; Mariani, M.; Giacobbo, F.; Covini, R.

2006-01-01

Among the severe accidents that can cause the release of radionuclides from an interim storage facility, with a consequent relevant radiological impact on the population, there is the impact of an aircraft on the facility. In this work, a safety assessment analysis for the case of an aircraft crash into an interim storage facility is tackled. To this aim a methodology, based upon DOE, IAEA and NUREG standard procedures and upon conservative yet realistic hypothesis, has been developed in order to evaluate the total radioactivity, source term, released to the biosphere in consequence of the impact, without recurring to the use of complicated numerical codes. The procedure consists in the identification of the accidental scenarios, in the evaluation of the consequent damage to the building structures and to the waste packages and in the determination of the total release of radionuclides through the building-atmosphere interface. The methodology here developed has been applied to the case of an aircraft crash into an interim storage facility currently under design. Results show that in case of perforation followed by a fire incident the total released activity would be greater of some orders of magnitude with respect to the case of mere perforation. (author)

Delineation of seismic source zones based on seismicity parameters ...

Indian Academy of Sciences (India)

In the present study, an attempt has been made to delineate seismic source zones in the study area (south India) based on the seismicity parameters. Seismicity parameters and the maximum probable earthquake for these source zones were evaluated and were used in the hazard evaluation. The probabilistic evaluation of ...

Prospects of Source-Separation-Based Sanitation Concepts: A Model-Based Study

Directory of Open Access Journals (Sweden)

Cees Buisman

2013-07-01

Full Text Available Separation of different domestic wastewater streams and targeted on-site treatment for resource recovery has been recognized as one of the most promising sanitation concepts to re-establish the balance in carbon, nutrient and water cycles. In this study a model was developed based on literature data to compare energy and water balance, nutrient recovery, chemical use, effluent quality and land area requirement in four different sanitation concepts: (1 centralized; (2 centralized with source-separation of urine; (3 source-separation of black water, kitchen refuse and grey water; and (4 source-separation of urine, feces, kitchen refuse and grey water. The highest primary energy consumption of 914 MJ/capita(cap/year was attained within the centralized sanitation concept, and the lowest primary energy consumption of 437 MJ/cap/year was attained within source-separation of urine, feces, kitchen refuse and grey water. Grey water bio-flocculation and subsequent grey water sludge co-digestion decreased the primary energy consumption, but was not energetically favorable to couple with grey water effluent reuse. Source-separation of urine improved the energy balance, nutrient recovery and effluent quality, but required larger land area and higher chemical use in the centralized concept.

Pixel-based parametric source depth map for Cerenkov luminescence imaging

International Nuclear Information System (INIS)

Altabella, L.; Spinelli, A.E.; Boschi, F.

2016-01-01

Optical tomography represents a challenging problem in optical imaging because of the intrinsically ill-posed inverse problem due to photon diffusion. Cerenkov luminescence tomography (CLT) for optical photons produced in tissues by several radionuclides (i.e.: 32P, 18F, 90Y), has been investigated using both 3D multispectral approach and multiviews methods. Difficult in convergence of 3D algorithms can discourage to use this technique to have information of depth and intensity of source. For these reasons, we developed a faster 2D corrected approach based on multispectral acquisitions, to obtain source depth and its intensity using a pixel-based fitting of source intensity. Monte Carlo simulations and experimental data were used to develop and validate the method to obtain the parametric map of source depth. With this approach we obtain parametric source depth maps with a precision between 3% and 7% for MC simulation and 5–6% for experimental data. Using this method we are able to obtain reliable information about the source depth of Cerenkov luminescence with a simple and flexible procedure

Source-Based Tasks in Writing Independent and Integrated Essays

Directory of Open Access Journals (Sweden)

Javad Gholami

2017-07-01

Full Text Available Integrated writing tasks have gained considerable attention in ESL and EFL writing assessment and are frequently needed and used in academic settings and daily life. However, they are very rarely practiced and promoted in writing classes. This paper explored the effects of source-based writing practice on EFL learners’ composing abilities and investigated the probable differences between those tasks and independent writing ones in improving Iranian EFL learners’ essay writing abilities. To this end, a quasi-experimental design was implemented to gauge EFL learners’ writing improvements using a pretest-posttest layout. Twenty female learners taking a TOEFL iBT preparation course were randomly divided into an only-writing group with just independent writing instruction and essay practice, and a hybrid-writing-approach group receiving instruction and practice on independent writing plus source-based essay writing for ten sessions. Based on the findings, the participants with hybrid writing practice outperformed their counterparts in integrated essay tests. Their superior performance was not observed in the case of traditional independent writing tasks. The present study calls for incorporating more source-based writing tasks in writing courses.

Very high flux steady state reactor and accelerator based sources

International Nuclear Information System (INIS)

Ludewig, H.; Todosow, M.; Simos, N.; Shapiro, S.; Hastings, J.

2004-01-01

With the number of steady state neutron sources in the US declining (including the demise of the Bnl HFBR) the remaining intense sources are now in Europe (i.e. reactors - ILL and FMR, accelerator - PSI). The intensity of the undisturbed thermal flux for sources currently in operation ranges from 10 14 n/cm 2 *s to 10 15 n/cm 2 *s. The proposed Advanced Neutron Source (ANS) was to be a high power reactor (about 350 MW) with a projected undisturbed thermal flux of 7*10 15 n/cm 2 *s but never materialized. The objective of the current study is to explore the requirements and implications of two source concepts with an undisturbed flux of 10 16 n/cm 2 *s. The first is a reactor based concept operating at high power density (10 MW/l - 15 MW/l) and a total power of 100 MW - 250 MW, depending on fissile enrichment. The second is an accelerator based concept relying on a 1 GeV - 1.5 GeV proton Linac with a total beam power of 40 MW and a liquid lead-bismuth eutectic target. In the reactor source study, the effects of fissile material enrichment, coolant temperature and pressure drop, and estimates of pressure vessel stress levels will be investigated. The fuel form for the reactor will be different from all other operating source reactors in that it is proposed to use an infiltrated graphitic structure, which has been developed for nuclear thermal propulsion reactor applications. In the accelerator based source the generation of spallation products and their activation levels, and the material damage sustained by the beam window will be investigated. (authors)

Analysis of accident sequences and source terms at waste treatment and storage facilities for waste generated by U.S. Department of Energy Waste Management Operations, Volume 3: Appendixes C-H

International Nuclear Information System (INIS)

Mueller, C.; Nabelssi, B.; Roglans-Ribas, J.

1995-04-01

This report contains the Appendices for the Analysis of Accident Sequences and Source Terms at Waste Treatment and Storage Facilities for Waste Generated by the U.S. Department of Energy Waste Management Operations. The main report documents the methodology, computational framework, and results of facility accident analyses performed as a part of the U.S. Department of Energy (DOE) Waste Management Programmatic Environmental Impact Statement (WM PEIS). The accident sequences potentially important to human health risk are specified, their frequencies are assessed, and the resultant radiological and chemical source terms are evaluated. A personal computer-based computational framework and database have been developed that provide these results as input to the WM PEIS for calculation of human health risk impacts. This report summarizes the accident analyses and aggregates the key results for each of the waste streams. Source terms are estimated and results are presented for each of the major DOE sites and facilities by WM PEIS alternative for each waste stream. The appendices identify the potential atmospheric release of each toxic chemical or radionuclide for each accident scenario studied. They also provide discussion of specific accident analysis data and guidance used or consulted in this report

Analysis of accident sequences and source terms at waste treatment and storage facilities for waste generated by U.S. Department of Energy Waste Management Operations, Volume 3: Appendixes C-H