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Title: Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory

Abstract

This research focuses on modelling reflectors in typical material testing reactors (MTRs). Equivalence theory is used to homogenise and collapse detailed transport solutions to generate equivalent nodal parameters and albedo boundary conditions for reflectors, for subsequent use in full core nodal diffusion codes. This approach to reflector modelling has been shown to be accurate for two-group large commercial light water reactor (LWR) analysis, but has not been investigated for MTRs. MTRs are smaller, with much larger leakage, environment sensitivity and multi-group spectrum dependencies than LWRs. This study aims to determine if this approach to reflector modelling is an accurate and plausible homogenisation technique for the modelling of small MTR cores. The successful implementation will result in simplified core models, better accuracy and improved efficiency of computer simulations. Codes used in this study include SCALE 6.1, OSCAR-4 and EQUIVA (the last two codes are developed and used at Necsa). The results show a five times reduction in calculational time for the proposed reduced reactor model compared to the traditional explicit model. The calculated equivalent parameters however show some sensitivity to the environment used to generate them. Differences in the results compared to the current explicit model, require more careful investigation includingmore » comparisons with a reference result, before its implementation can be recommended. (authors)« less

Authors:
 [1];  [2]
  1. South African Nuclear Energy Corporation (Necsa), PO Box 582, Pretoria, 0001 (South Africa)
  2. Calvera Consultants, PO Box 150, Strubensvallei, 1735 (South Africa)
Publication Date:
Research Org.:
American Nuclear Society, Inc., 555 N. Kensington Avenue, La Grange Park, Illinois 60526 (United States)
OSTI Identifier:
22105909
Resource Type:
Conference
Resource Relation:
Conference: PHYSOR 2012: Conference on Advances in Reactor Physics - Linking Research, Industry, and Education, Knoxville, TN (United States), 15-20 Apr 2012; Other Information: Country of input: France; 18 refs.
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; ALBEDO; BOUNDARY CONDITIONS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; DIFFUSION; ENVIRONMENTAL EFFECTS; ENVIRONMENTAL IMPACTS; GROUP THEORY; MATERIALS TESTING; REACTOR CORES; WATER COOLED REACTORS; WATER MODERATED REACTORS

Citation Formats

Theron, S. A., and Reitsma, F. Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory. United States: N. p., 2012. Web.
Theron, S. A., & Reitsma, F. Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory. United States.
Theron, S. A., and Reitsma, F. Sun . "Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory". United States.
@article{osti_22105909,
title = {Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory},
author = {Theron, S. A. and Reitsma, F.},
abstractNote = {This research focuses on modelling reflectors in typical material testing reactors (MTRs). Equivalence theory is used to homogenise and collapse detailed transport solutions to generate equivalent nodal parameters and albedo boundary conditions for reflectors, for subsequent use in full core nodal diffusion codes. This approach to reflector modelling has been shown to be accurate for two-group large commercial light water reactor (LWR) analysis, but has not been investigated for MTRs. MTRs are smaller, with much larger leakage, environment sensitivity and multi-group spectrum dependencies than LWRs. This study aims to determine if this approach to reflector modelling is an accurate and plausible homogenisation technique for the modelling of small MTR cores. The successful implementation will result in simplified core models, better accuracy and improved efficiency of computer simulations. Codes used in this study include SCALE 6.1, OSCAR-4 and EQUIVA (the last two codes are developed and used at Necsa). The results show a five times reduction in calculational time for the proposed reduced reactor model compared to the traditional explicit model. The calculated equivalent parameters however show some sensitivity to the environment used to generate them. Differences in the results compared to the current explicit model, require more careful investigation including comparisons with a reference result, before its implementation can be recommended. (authors)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {7}
}

Conference:
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