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Title: First Conclusions of the WPEC/Subgroup-22 Nuclear Data for Improved LEU-LWR Reactivity Predictions

Abstract

This paper is a summary of a collective work in the framework of the Working Party in International Nuclear Data Evaluation and Co-operation (WPEC) to investigate the reasons for systematic reactivity underprediction of thermal LEU-LWR (Low-Enriched Uranium, Light-Water Reactor). This keff underprediction ({approx_equal} -500 pcm) is observed with the most recent nuclear data libraries (ENDF/B-VI.8, JENDL3.3 and JEFF3.0) This report reviews the evaluation work performed at several laboratories [Oak Ridge National Laboratory (ORNL), Los Alamos National Laboratory (LANL), Commissariat a l'energie atomique de Bruyeres-Le-Chatel (CEA-BRC), International Atomic Energy Agency (IAEA)] as well as the integral tests (mainly at LANL, Knoll Atomic Power Laboratory (KAPL), Bettis Atomic Power Laboratory (BAPL), Nuclear Research and Consultancy Group NRG-Petten, CEA and IAEA) of the successive versions of the new evaluated files. The present status of the work can be summarized as follows: Improved evaluations of 238U inelastic data proposed by LANL and CEA-BRC were tested against integral benchmarks and partially improve the reactivity prediction. The thermal capture cross-section of 238U has been revised, and a new evaluation of 238U resonance parameters, up to 20 keV, is in progress at ORNL. Integral tests have ensured that the modifications of 238U capture cross-section in the thermalmore » and resolved range were still compatible with 238U integral measurements (238U capture rate ratios measured in critical facilities and 239Pu build-up prediction in a depleted pressurized water reactor (PWR) assembly).It is demonstrated that the combination of the new inelastic data (LANL or BRC) with the preliminary ORNL resonance parameter set gives a good correction of the reactivity under-estimation. The provisional conclusions of this collective work are expected to contribute toward the improvement of the future versions of nuclear data libraries.« less

Authors:
 [1]
  1. CEA-DEN-Cadarache, 13108 Saint Paul Lez Durance, Cedex (France)
Publication Date:
OSTI Identifier:
20722597
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 769; Journal Issue: 1; Conference: International conference on nuclear data for science and technology, Santa Fe, NM (United States), 26 Sep - 1 Oct 2004; Other Information: DOI: 10.1063/1.1945048; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BENCHMARKS; CAPTURE; CORRECTIONS; ENRICHED URANIUM; EVALUATION; KEV RANGE; LANL; NUCLEAR DATA COLLECTIONS; NUCLEAR REACTIONS; ORNL; PLUTONIUM 239; PWR TYPE REACTORS; REACTIVITY; RESONANCE; REVIEWS; URANIUM 238

Citation Formats

Courcelle, Arnaud. First Conclusions of the WPEC/Subgroup-22 Nuclear Data for Improved LEU-LWR Reactivity Predictions. United States: N. p., 2005. Web. doi:10.1063/1.1945048.
Courcelle, Arnaud. First Conclusions of the WPEC/Subgroup-22 Nuclear Data for Improved LEU-LWR Reactivity Predictions. United States. https://doi.org/10.1063/1.1945048
Courcelle, Arnaud. 2005. "First Conclusions of the WPEC/Subgroup-22 Nuclear Data for Improved LEU-LWR Reactivity Predictions". United States. https://doi.org/10.1063/1.1945048.
@article{osti_20722597,
title = {First Conclusions of the WPEC/Subgroup-22 Nuclear Data for Improved LEU-LWR Reactivity Predictions},
author = {Courcelle, Arnaud},
abstractNote = {This paper is a summary of a collective work in the framework of the Working Party in International Nuclear Data Evaluation and Co-operation (WPEC) to investigate the reasons for systematic reactivity underprediction of thermal LEU-LWR (Low-Enriched Uranium, Light-Water Reactor). This keff underprediction ({approx_equal} -500 pcm) is observed with the most recent nuclear data libraries (ENDF/B-VI.8, JENDL3.3 and JEFF3.0) This report reviews the evaluation work performed at several laboratories [Oak Ridge National Laboratory (ORNL), Los Alamos National Laboratory (LANL), Commissariat a l'energie atomique de Bruyeres-Le-Chatel (CEA-BRC), International Atomic Energy Agency (IAEA)] as well as the integral tests (mainly at LANL, Knoll Atomic Power Laboratory (KAPL), Bettis Atomic Power Laboratory (BAPL), Nuclear Research and Consultancy Group NRG-Petten, CEA and IAEA) of the successive versions of the new evaluated files. The present status of the work can be summarized as follows: Improved evaluations of 238U inelastic data proposed by LANL and CEA-BRC were tested against integral benchmarks and partially improve the reactivity prediction. The thermal capture cross-section of 238U has been revised, and a new evaluation of 238U resonance parameters, up to 20 keV, is in progress at ORNL. Integral tests have ensured that the modifications of 238U capture cross-section in the thermal and resolved range were still compatible with 238U integral measurements (238U capture rate ratios measured in critical facilities and 239Pu build-up prediction in a depleted pressurized water reactor (PWR) assembly).It is demonstrated that the combination of the new inelastic data (LANL or BRC) with the preliminary ORNL resonance parameter set gives a good correction of the reactivity under-estimation. The provisional conclusions of this collective work are expected to contribute toward the improvement of the future versions of nuclear data libraries.},
doi = {10.1063/1.1945048},
url = {https://www.osti.gov/biblio/20722597}, journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 769,
place = {United States},
year = {Tue May 24 00:00:00 EDT 2005},
month = {Tue May 24 00:00:00 EDT 2005}
}