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Title: Photon dose rates from spent fuel assemblies with relation to self-protection (Rev. 1)

Abstract

Photon dose rates as a function of fission product decay times have been calculated for spent fuel assemblies typical of MTR-type research and test reactors. Based upon these dose rates, the length of time that a spent fuel assembly will be self-protecting (dose rate greater than 100 rem/h at 1 m in air) can be estimated knowing the mass of fuel burned, the fraction of fuel burned, and the fuel assembly specific power density.

Authors:
;
Publication Date:
Research Org.:
Argonne National Lab., IL (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
272552
Report Number(s):
ANL/RERTR/TM-25
ON: DE96013490; TRN: 96:017715
DOE Contract Number:
W-31109-ENG-38
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Feb 1996
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; 22 NUCLEAR REACTOR TECHNOLOGY; PHOTONS; DOSE RATES; SPENT FUEL ELEMENTS; RESEARCH AND TEST REACTORS; MONTE CARLO METHOD; DIAGRAMS; NUMERICAL DATA

Citation Formats

Pond, R.B., and Matos, J.E.. Photon dose rates from spent fuel assemblies with relation to self-protection (Rev. 1). United States: N. p., 1996. Web. doi:10.2172/272552.
Pond, R.B., & Matos, J.E.. Photon dose rates from spent fuel assemblies with relation to self-protection (Rev. 1). United States. doi:10.2172/272552.
Pond, R.B., and Matos, J.E.. Thu . "Photon dose rates from spent fuel assemblies with relation to self-protection (Rev. 1)". United States. doi:10.2172/272552. https://www.osti.gov/servlets/purl/272552.
@article{osti_272552,
title = {Photon dose rates from spent fuel assemblies with relation to self-protection (Rev. 1)},
author = {Pond, R.B. and Matos, J.E.},
abstractNote = {Photon dose rates as a function of fission product decay times have been calculated for spent fuel assemblies typical of MTR-type research and test reactors. Based upon these dose rates, the length of time that a spent fuel assembly will be self-protecting (dose rate greater than 100 rem/h at 1 m in air) can be estimated knowing the mass of fuel burned, the fraction of fuel burned, and the fuel assembly specific power density.},
doi = {10.2172/272552},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 1996},
month = {Thu Feb 01 00:00:00 EST 1996}
}

Technical Report:

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  • Photon dose rates as a function of fission product decay times have been calculated for spent fuel assemblies typical of MTR-type research and test reactors. Based upon these dose rates, the length of time that a spent fuel assembly will be self-protecting (dose rate greater than 100 rem/h at 1 m in air) can be estimated knowing the mass of fuel burned, the fraction of fuel burned, and the fuel assembly specific power density. The calculated dose rates cover 20 years of fission product decay, spent fuel with up to 80% {sup 235}U burnup and assembly power densities ranging frommore » 0.089 to 2.857 MW/kg{sup 235}U. Most of the results are unshielded dose rates at 1 m in air with some shielded dose rates at 40 cm in water. Dose rate sensitivity estimates have been evaluated for a variety of MTR fuel assembly designs and for uncertainties in both the physical and analytical models of the fuel assemblies.« less
  • As part of the Department of Energy`s spent nuclear fuel acceptance criteria, the mass of uranium and transuranic elements in spent research reactor fuel must be specified. These data are, however, not always known or readily determined. It is the purpose of this report to provide estimates of these data for some of the more common research reactor fuel assembly types. The specific types considered here are MTR, TRIGA and DIDO fuel assemblies. The degree of physical protection given to spent fuel assemblies is largely dependent upon the photon dose rate of the spent fuel material. These data also, aremore » not always known or readily determined. Because of a self-protecting dose rate level of radiation (dose rate greater than 100 ren-x/h at I m in air), it is important to know the dose rate of spent fuel assemblies at all time. Estimates of the photon dose rate for spent MTR, TRIGA and DIDO-type fuel assemblies are given in this report.« less
  • This report provides a preliminary assessment of the computational tools and existing methods used to obtain radiation dose rates from shielded spent nuclear fuel and high-level radioactive waste (HLW). Particular emphasis is placed on analysis tools and techniques applicable to facilities/equipment designed for the transport or storage of spent nuclear fuel or HLW. Applications to cask transport, storage, and facility handling are considered. The report reviews the analytic techniques for generating appropriate radiation sources, evaluating the radiation transport through the shield, and calculating the dose at a desired point or surface exterior to the shield. Discrete ordinates, Monte Carlo, andmore » point kernel methods for evaluating radiation transport are reviewed, along with existing codes and data that utilize these methods. A literature survey was employed to select a cadre of codes and data libraries to be reviewed. The selection process was based on specific criteria presented in the report. Separate summaries were written for several codes (or family of codes) that provided information on the method of solution, limitations and advantages, availability, data access, ease of use, and known accuracy. For each data library, the summary covers the source of the data, applicability of these data, and known verification efforts. Finally, the report discusses the overall status of spent fuel shielding analysis techniques and attempts to illustrate areas where inaccuracy and/or uncertainty exist. The report notes the advantages and limitations of several analysis procedures and illustrates the importance of using adequate cross-section data sets. Additional work is recommended to enable final selection/validation of analysis tools that will best meet the US Department of Energy's requirements for use in developing a viable HLW management system. 188 refs., 16 figs., 27 tabs.« less
  • Dose-rate conversion factors for external exposure to photon and electron radiation have been calculated for 240 radionuclides of potential importance in routine releases from nuclear fuel cycle facilities. Dose-rate conversion factors for immersion in contaminated air, immersion in contaminated water, and exposure to a contaminated ground surface are estimated for tissue-equivalent material at the body surface of an exposed individual. For each exposure mode, photon dose-rate conversion factors are also estimated for 22 body organs. The calculations assume that the contaminated air, water, and ground surface are infinite in extent and that the radionuclide concentration is uniform. Dose-rate conversion factorsmore » for immersion in contaminated air and water are based on the requirement that all energy emitted in the decay of a radionuclide is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated for a height of 1 m using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air. The computer code DOSFACTER written to perform the calculations is described and documented.« less
  • Calculations of the skyshine gamma-ray dose rates from three spent fuel storage pools under worst case accident conditions have been made using the discrete ordinates code DOT-IV and the Monte Carlo code MORSE and have been compared to those of two previous methods. The DNA 37N-21G group cross-section library was utilized in the calculations, together with the Claiborne-Trubey gamma-ray dose factors taken from the same library. Plots of all results are presented. It was found that the dose was a strong function of the iron thickness over the fuel assemblies, the initial angular distribution of the emitted radiation, and themore » photon source near the top of the assemblies. 16 refs., 11 figs., 7 tabs.« less