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

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 (≈ −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 d...

[1]  A. Santamarina,et al.  Evaluation of 238U Resonance Parameters from 0 to 20 keV , 2005 .

[2]  Andrej Trkov,et al.  Revisiting the 238U Thermal Capture Cross Section and Gamma-Ray Emission Probabilities from 239Np Decay , 2005 .

[3]  A. C. Kahler,et al.  Monte Carlo Eigenvalue Calculations with ENDF/B-VI.8, JEFF-3.0, and JENDL-3.3 Cross Sections for a Selection of International Criticality Safety Benchmark Evaluation Project Handbook Benchmarks , 2003 .

[4]  A. Hasegawa,et al.  Evaluation of the unresolved resonance range of 238U , 2002 .

[5]  M. Mattes,et al.  Validation of Nuclear Data Libraries for Reactor Safety and Design Calculations , 2002 .

[6]  R. Q. Wright,et al.  R-Matrix Evaluation of 16O Neutron Cross Sections up to 6.3 MeV , 2000 .

[7]  R. Q. Wright,et al.  R-matrix analysis of 235U neutron transmission and cross-section measurements in the 0- to 2.25-keV energy range , 1999 .

[8]  D. G. Naberejnev,et al.  The Influence of Crystalline Binding on Resonant Absorption and Reaction Rates , 1999 .

[9]  Naohiro Hirakawa,et al.  Measurement of Double-Differential Neutron Emission Spectra from Uranium-238 , 1990 .

[10]  Michael Sowerby.  Summary of the work of the neandc task force on U-238 , 1986 .

[11]  W. P. Poenitz,et al.  Measurements of the 238U(n, γ) Cross Section at Thermal and Fast Neutron Energies , 1981 .

[12]  R. B. Perez,et al.  Measurement and Resonance Analysis of Neutron Transmission Through Uranium-238 , 1979 .

[13]  E. G. Silver,et al.  Precise measurement and analysis of neutron transmission through ²³⁸U , 1977 .

[14]  W. Lamb.  Capture of Neutrons by Atoms in a Crystal , 1939 .

[15]  Z. Révay,et al.  Non-destructive interrogation of uranium using PGAA , 2004 .

[16]  N. M. Larson,et al.  Status of a New Evaluation of the Neutron Resonance Parameters of 238 U at ORNL , 2004 .

[17]  L. Prestes.  THE SPECTRAL INDICES OF THE IPEN/MB-01 REACTOR: MEASUREMENTS AND CALCULATION , 2002 .

[18]  G. D. Saussure,et al.  High energy resolution measurement of the /sup 238/U neutron capture yield in the energy region between 1 and 100 keV , 1988 .

[19]  H. Weaver,et al.  Measurement of the Uranium-238 Capture Cross Section for Incident Neutron Energies up to 100 keV , 1973 .