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Spent fuel transportation risk assessment: Routine transportation

Packaging, Transport, Storage and Security of Radioactive Material

Weiner, Ruth F.

The RADTRAN model for calculating radiation doses is based on the well understood behaviour of ionising radiation. Absorption of ionising radiation depends on the energy and type of radiation and on the absorbing material. The casks that are used to transport spent nuclear fuel have walls that absorb most of the emitted ionising radiation and thereby shield the public and the workers. For routine transportation, RADTRAN models the cask as a sphere and assumes that the longest dimension of the trailer or railcar carrying the cask is the same as that of the cask. The dose rate in Sv/h at one metre from the cask is modelled as a virtual source at the centre of a sphere whose diameter is the longest dimension of the actual spent fuel cask. People who live along the cask's route and the people in vehicles that share the route are exposed to external radiation from the cask. The dose to workers and the public from a cask during routine transportation depends on the time that the workers or public are exposed to the cask, the distance from the cask, and the cask's external radiation. When the vehicle carrying the cask is travelling along the route, the faster the vehicle goes, the less exposure to anyone along the vehicle's route. Therefore, an individual member of the public receives the largest dose from a moving vehicle when he or she is as close as possible to the vehicle, and the vehicle is travelling as slowly as possible. In the present analysis, these doses are in the range of four to seven nanosieverts. Collective doses along the route depend on the size of the exposed population. In this study, such doses were of the order of 0?1 person-millisieverts. The appropriate comparison between the collective dose from a shipment of spent fuel is not a comparison between the radiation dose from the shipment and zero dose, but between the background radiation dose in the presence and absence of a shipment, e.g. 8.810096 person-Sv if there is a shipment and 8.81000 person-Sv if there is no shipment. © W. S. Maney & Son Ltd 2014.

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RADTRAN 6 technical manual

Weiner, Ruth F.; Dennis, Matthew L.

This Technical Manual contains descriptions of the calculation models and mathematical and numerical methods used in the RADTRAN 6 computer code for transportation risk and consequence assessment. The RADTRAN 6 code combines user-supplied input data with values from an internal library of physical and radiological data to calculate the expected radiological consequences and risks associated with the transportation of radioactive material. Radiological consequences and risks are estimated with numerical models of exposure pathways, receptor populations, package behavior in accidents, and accident severity and probability.

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Ingestion dose model for transportation risk assessment

Packaging, Transport, Storage and Security of Radioactive Material

Weiner, Ruth F.; Heames, T.J.

Risks of transporting radioactive materials can be estimated using the programme and code RADTRAN. Potential radiation doses to various receptors are calculated by RADTRAN, including doses from routine, incident free transportation and from transportation accidents. If radioactive material is released from a transportation vehicle in an accident, agricultural products in the plume footprint could be contaminated. This paper discusses a method for calculating radiation doses from ingestion of such radioactively contaminated food stuffs. Transportation of radioactive materials occurs throughout the USA, so that agricultural products along many transportation corridors could be affected. However, doses from ingesting agricultural crops contaminated from a traffic accident would be very small compared to natural background radiation. © W. S. Maney & Son Ltd 2014.

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RADTRAN 6/RadCat 6 user guide

Weiner, Ruth F.; Farnum, Cathy O.

This document provides a detailed discussion and a guide for the use of the RadCat 6.0 Graphical User Interface input file generator for the RADTRAN code, Version 6. RadCat 6.0 integrates the newest analysis capabilities of RADTRAN 6.0, including an economic model, updated loss-of-lead shielding model, a new ingestion dose model, and unit conversion. As of this writing, the RADTRAN version in use is RADTRAN 6.02.

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A review of the risks and risk models for transporting very radioactive materials

13th International High-Level Radioactive Waste Management Conference 2011, IHLRWMC 2011

Weiner, Ruth F.

This paper reviews how the risks of transporting very radioactive materials are modeled and how the resulting doses to the public compare with commonly experienced radiation doses like background radiation. Both routine, incident-free transportation and transportation accidents are discussed. Only transportation of used nuclear fuel and high-level radioactive waste is discussed.

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Transportation implications of a closed fuel cycle

Weiner, Ruth F.; Sorenson, Ken B.; Dennis, Matthew L.

Transportation for each step of a closed fuel cycle is analyzed in consideration of the availability of appropriate transportation infrastructure. The United States has both experience and certified casks for transportation that may be required by this cycle, except for the transport of fresh and used MOX fuel and fresh and used Advanced Burner Reactor (ABR) fuel. Packaging that had been used for other fuel with somewhat similar characteristics may be appropriate for these fuels, but would be inefficient. Therefore, the required neutron and gamma shielding, heat dissipation, and criticality were calculated for MOX and ABR fresh and spent fuel. Criticality would not be an issue, but the packaging design would need to balance neutron shielding and regulatory heat dissipation requirements.

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PAT-1 safety analysis report addendum

Yoshimura, Richard H.; Morrow, Charles W.; Weiner, Ruth F.; Harding, David C.; Heitman, Lili A.; Kalan, Robert K.; Lopez Mestre, Carlos L.; Miller, David R.; Schmale, David T.; Knorovsky, Gerald A.

The Plutonium Air Transportable Package, Model PAT-1, is certified under Title 10, Code of Federal Regulations Part 71 by the U.S. Nuclear Regulatory Commission (NRC) per Certificate of Compliance (CoC) USA/0361B(U)F-96 (currently Revision 9). The purpose of this SAR Addendum is to incorporate plutonium (Pu) metal as a new payload for the PAT-1 package. The Pu metal is packed in an inner container (designated the T-Ampoule) that replaces the PC-1 inner container. The documentation and results from analysis contained in this addendum demonstrate that the replacement of the PC-1 and associated packaging material with the T-Ampoule and associated packaging with the addition of the plutonium metal content are not significant with respect to the design, operating characteristics, or safe performance of the containment system and prevention of criticality when the package is subjected to the tests specified in 10 CFR 71.71, 71.73 and 71.74.

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PAT-1 safety analysis report addendum author responses to request for additional information

Yoshimura, Richard H.; Knorovsky, Gerald A.; Morrow, Charles W.; Weiner, Ruth F.; Harding, David C.; Heitman, Lili A.; Lopez Mestre, Carlos L.; Kalan, Robert K.; Miller, David R.; Schmale, David T.

The Plutonium Air Transportable Package, Model PAT-1, is certified under Title 10, Code of Federal Regulations Part 71 by the U.S. Nuclear Regulatory Commission (NRC) per Certificate of Compliance (CoC) USA/0361B(U)F-96 (currently Revision 9). The National Nuclear Security Administration (NNSA) submitted SAND Report SAND2009-5822 to NRC that documented the incorporation of plutonium (Pu) metal as a new payload for the PAT-1 package. NRC responded with a Request for Additional Information (RAI), identifying information needed in connection with its review of the application. The purpose of this SAND report is to provide the authors responses to each RAI. SAND Report SAND2010-6106 containing the proposed changes to the Addendum is provided separately.

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End of FY10 report - used fuel disposition technical bases and lessons learned : legal and regulatory framework for high-level waste disposition in the United States

Rechard, Robert P.; Weiner, Ruth F.

This report examines the current policy, legal, and regulatory framework pertaining to used nuclear fuel and high level waste management in the United States. The goal is to identify potential changes that if made could add flexibility and possibly improve the chances of successfully implementing technical aspects of a nuclear waste policy. Experience suggests that the regulatory framework should be established prior to initiating future repository development. Concerning specifics of the regulatory framework, reasonable expectation as the standard of proof was successfully implemented and could be retained in the future; yet, the current classification system for radioactive waste, including hazardous constituents, warrants reexamination. Whether or not consideration of multiple sites are considered simultaneously in the future, inclusion of mechanisms such as deliberate use of performance assessment to manage site characterization would be wise. Because of experience gained here and abroad, diversity of geologic media is not particularly necessary as a criterion in site selection guidelines for multiple sites. Stepwise development of the repository program that includes flexibility also warrants serious consideration. Furthermore, integration of the waste management system from storage, transportation, and disposition, should be examined and would be facilitated by integration of the legal and regulatory framework. Finally, in order to enhance acceptability of future repository development, the national policy should be cognizant of those policy and technical attributes that enhance initial acceptance, and those policy and technical attributes that maintain and broaden credibility.

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Transportation scenarios for risk analysis

Weiner, Ruth F.

Transportation risk, like any risk, is defined by the risk triplet: what can happen (the scenario), how likely it is (the probability), and the resulting consequences. This paper evaluates the development of transportation scenarios, the associated probabilities, and the consequences. The most likely radioactive materials transportation scenario is routine, incident-free transportation, which has a probability indistinguishable from unity. Accident scenarios in radioactive materials transportation are of three different types: accidents in which there is no impact on the radioactive cargo, accidents in which some gamma shielding may be lost but there is no release of radioactive material, and accident in which radioactive material may potentially be released. Accident frequencies, obtainable from recorded data validated by the U.S. Department of Transportation, are considered equivalent to accident probabilities in this study. Probabilities of different types of accidents are conditional probabilities, conditional on an accident occurring, and are developed from event trees. Development of all of these probabilities and the associated highway and rail accident event trees are discussed in this paper.

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Review of the technical bases of 40 CFR Part 190

McMahon, Kevin A.; Bixler, Nathan E.; Siegel, Malcolm D.; Weiner, Ruth F.

The dose limits for emissions from the nuclear fuel cycle were established by the Environmental Protection Agency in 40 CFR Part 190 in 1977. These limits were based on assumptions regarding the growth of nuclear power and the technical capabilities of decontamination systems as well as the then-current knowledge of atmospheric dispersion and the biological effects of ionizing radiation. In the more than thirty years since the adoption of the limits, much has changed with respect to the scale of nuclear energy deployment in the United States and the scientific knowledge associated with modeling health effects from radioactivity release. Sandia National Laboratories conducted a study to examine and understand the methodologies and technical bases of 40 CFR 190 and also to determine if the conclusions of the earlier work would be different today given the current projected growth of nuclear power and the advances in scientific understanding. This report documents the results of that work.

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Incorporating uncertainty in RADTRAN 6.0 input files

Weiner, Ruth F.

Uncertainty may be introduced into RADTRAN analyses by distributing input parameters. The MELCOR Uncertainty Engine (Gauntt and Erickson, 2004) has been adapted for use in RADTRAN to determine the parameter shape and minimum and maximum of the distribution, to sample on the distribution, and to create an appropriate RADTRAN batch file. Coupling input parameters is not possible in this initial application. It is recommended that the analyst be very familiar with RADTRAN and able to edit or create a RADTRAN input file using a text editor before implementing the RADTRAN Uncertainty Analysis Module. Installation of the MELCOR Uncertainty Engine is required for incorporation of uncertainty into RADTRAN. Gauntt and Erickson (2004) provides installation instructions as well as a description and user guide for the uncertainty engine.

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Dose estimates in a loss of lead shielding truck accident

Dennis, Matthew L.; Weiner, Ruth F.; Osborn, Douglas M.

The radiological transportation risk & consequence program, RADTRAN, has recently added an updated loss of lead shielding (LOS) model to it most recent version, RADTRAN 6.0. The LOS model was used to determine dose estimates to first-responders during a spent nuclear fuel transportation accident. Results varied according to the following: type of accident scenario, percent of lead slump, distance to shipment, and time spent in the area. This document presents a method of creating dose estimates for first-responders using RADTRAN with potential accident scenarios. This may be of particular interest in the event of high speed accidents or fires involving cask punctures.

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RadCat 3.0 user guide

Weiner, Ruth F.; Dennis, Matthew L.; Osborn, Douglas M.

RADTRAN is an internationally accepted program and code for calculating the risks of transporting radioactive materials. The first versions of the program, RADTRAN I and II, were developed for NUREG-0170 (USNRC, 1977), the first environmental statement on transportation of radioactive materials. RADTRAN and its associated software have undergone a number of improvements and advances consistent with improvements in both available data and computer technology. The version of RADTRAN currently bundled with RadCat is RADTRAN 6.0. This document provides a detailed discussion and a guide for the use of the RadCat 3.0 Graphical User Interface input file generator for the RADTRAN code. RadCat 3.0 integrates the newest analysis capabilities of RADTRAN 6.0 which includes an economic model, updated loss-of-lead shielding model, and unit conversion. As of this writing, the RADTRAN version in use is RADTRAN 6.0.

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Risks of transportation along various routes to the Nevada Test Site

Weiner, Ruth F.

Residents of Southern Nevada have expressed interest in the risks posed by transportation of radioactive materials to the Nevada Test Site for disposal. Residents of the urban sections of Clark County, in particular, are concerned because the trucks carrying this material pass through fairly densely populated areas on both primary and secondary highways. Excellent studies by the Desert Research Institute (Miller, et al, 2005; 2007) measured the external radiation doses from these trucks and provided a benchmark for estimating the doses sustained by the population along the transportation routes. The studies did not, however, assess the doses to the population in the event of an accident involving these trucks. The present study estimates doses to the population along these routes and to various individual receptors, both for routine, incident-free transportation and for transportation accidents.

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RADTRAN/RADCAT user guide

Weiner, Ruth F.; Mills, G.S.; O'Donnell, Brandon M.; Orcutt, David J.

RADTRAN is a program and code for calculating the risks of transporting radioactive materials. The first versions of the program, RADTRAN I and II, were developed for NUREG-0170 (USNRC, 1977), the first environmental impact statement on transportation of radioactive materials. RADTRAN and its associated software have undergone a number of improvements and advances consistent with improvements in computer technology.

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Benchmarking RADTRAN loss of shielding model for a SNF cask

Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM

Boyd, Adam M.; Worthy, Danielle K.; Osborn, Douglas M.; Weiner, Ruth F.

The RADTRAN Loss of Shielding (LOS) Model was benchmarked using MicroShield 6.20®. This analysis considers an intact spent fuel truck cask as well as a set of damaged truck casks. Ratios of dose rates are calculated for casks with a loss of lead shielding to those of intact casks, and are then compared to ratios generated by the LOS model. LOS Model results were considered verified if two main constraints were satisfied. First, the dose rate profiles for both the LOS and MicroShield 6.20® calculations must have the same general shape and behavior. Additionally, the largest factor difference between any two points of the dose rate profiles may not exceed an order of magnitude. Reasonable agreement is shown for large-fraction LOS scenarios; however the differences in results are not satisfactory for cases with small fractions of slump.

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Verification and Validation of RADTRAN 5.5

Weiner, Ruth F.; Mills, G.S.

This document contains a description of the verification and validation process used for the RADTRAN 5.5 code. The verification and validation process ensured the proper calculational models and mathematical and numerical methods were used in the RADTRAN 5.5 code for the determination of risk and consequence assessments. The differences between RADTRAN 5 and RADTRAN 5.5 are the addition of tables, an expanded isotope library, and the additional User-Defined meteorological option for accident dispersion. 3

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RadCat 2.0 User Guide

Osborn, Douglas M.; Weiner, Ruth F.; Mills, G.S.

This document provides a detailed discussion and a guide for the use of the RadCat 2.0 Graphical User Interface input file generator for the RADTRAN 5.5 code. The differences between RadCat 2.0 and RadCat 1.0 can be attributed to the differences between RADTRAN 5 and RADTRAN 5.5 as well as clarification for some of the input parameters. 3

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RADTRAN 5 user guide

Weiner, Ruth F.; Kanipe, Frances L.; Weiner, Ruth F.

This User Guide for the RADTRAN 5 computer code for transportation risk analysis describes basic risk concepts and provides the user with step-by-step directions for creating input files by means of either the RADDOG input file generator software or a text editor. It also contains information on how to interpret RADTRAN 5 output, how to obtain and use several types of important input data, and how to select appropriate analysis methods. Appendices include a glossary of terms, a listing of error messages, data-plotting information, images of RADDOG screens, and a table of all data in the internal radionuclide library.

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A multi-attribute utility decision analysis for treatment alternatives for the DOE/SR aluminum-based spent nuclear fuel

Risk Analysis

Davis, F.J.; Weiner, Ruth F.; Wheeler, Timothy A.; Sorenson, Ken B.; Kuzio, Kenneth A.; Wheeler, Timothy A.

A multi-attribute utility analysis is applied to a decision process to select a treatment method for the management of aluminum-based spent nuclear fuel (Al-SNF) owned by the US Department of Energy (DOE). DOE will receive, treat, and temporarily store Al-SNF, most of which is composed of highly enriched uranium, at its Savannah River Site in South Carolina. DOE intends ultimately to send the treated Al-SNF to a geologic repository for permanent disposal. DOE initially considered ten treatment alternatives for the management of Al-SNF, and has narrowed the choice to two of these: the direct disposal and melt and dilute alternatives. The decision analysis presented in this document focuses on a formal decision process used to evaluate these two remaining alternatives.

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60 Results
60 Results