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Title: A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - II. Verifications

Abstract

A new methodology has been developed recently to treat resonance self-shielding in systems for which the fuel compact region of a reactor lattice consists of small fuel grains dispersed in a graphite matrix. The theoretical development adopts equivalence theory in both micro- and macro-level heterogeneities to provide approximate analytical expressions for the shielded cross sections, which may be interpolated from a table of resonance integrals or Bondarenko factors using a modified background cross section as the interpolation parameter. This paper describes the first implementation of the theoretical equations in a reactor analysis code. In order to reduce discrepancies caused by use of the rational approximation for collision probabilities in the original derivation, a new formulation for a doubly heterogeneous Bell factor is developed in this paper to improve the accuracy of doubly heterogeneous expressions. This methodology is applied to a wide range of pin cell and assembly test problems with varying geometry parameters, material compositions, and temperatures, and the results are compared with continuous-energy Monte Carlo simulations to establish the accuracy and range of applicability of the new approach. It is shown that the new doubly heterogeneous self-shielding method including the Bell factor correction gives good agreement with reference Montemore » Carlo results.« less

Authors:
 [1];  [1];  [1];  [2]
  1. Ulsan National Institute of Science and Technology (UNIST), Ulju-gun (Korea)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1223635
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Science and Engineering
Additional Journal Information:
Journal Volume: 180; Journal Issue: 1; Journal ID: ISSN 0029-5639
Publisher:
American Nuclear Society - Taylor & Francis
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS

Citation Formats

Choi, Sooyoung, Kong, Chidong, Lee, Deokjung, and Williams, Mark L. A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - II. Verifications. United States: N. p., 2015. Web. doi:10.13182/NSE14-72.
Choi, Sooyoung, Kong, Chidong, Lee, Deokjung, & Williams, Mark L. A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - II. Verifications. United States. https://doi.org/10.13182/NSE14-72
Choi, Sooyoung, Kong, Chidong, Lee, Deokjung, and Williams, Mark L. 2015. "A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - II. Verifications". United States. https://doi.org/10.13182/NSE14-72. https://www.osti.gov/servlets/purl/1223635.
@article{osti_1223635,
title = {A New Equivalence Theory Method for Treating Doubly Heterogeneous Fuel - II. Verifications},
author = {Choi, Sooyoung and Kong, Chidong and Lee, Deokjung and Williams, Mark L.},
abstractNote = {A new methodology has been developed recently to treat resonance self-shielding in systems for which the fuel compact region of a reactor lattice consists of small fuel grains dispersed in a graphite matrix. The theoretical development adopts equivalence theory in both micro- and macro-level heterogeneities to provide approximate analytical expressions for the shielded cross sections, which may be interpolated from a table of resonance integrals or Bondarenko factors using a modified background cross section as the interpolation parameter. This paper describes the first implementation of the theoretical equations in a reactor analysis code. In order to reduce discrepancies caused by use of the rational approximation for collision probabilities in the original derivation, a new formulation for a doubly heterogeneous Bell factor is developed in this paper to improve the accuracy of doubly heterogeneous expressions. This methodology is applied to a wide range of pin cell and assembly test problems with varying geometry parameters, material compositions, and temperatures, and the results are compared with continuous-energy Monte Carlo simulations to establish the accuracy and range of applicability of the new approach. It is shown that the new doubly heterogeneous self-shielding method including the Bell factor correction gives good agreement with reference Monte Carlo results.},
doi = {10.13182/NSE14-72},
url = {https://www.osti.gov/biblio/1223635}, journal = {Nuclear Science and Engineering},
issn = {0029-5639},
number = 1,
volume = 180,
place = {United States},
year = {Mon Mar 09 00:00:00 EDT 2015},
month = {Mon Mar 09 00:00:00 EDT 2015}
}

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