239Pu nuclear data improvements in thermal and epithermal neutron ranges

D. Bernard; E. Fort; A. Courcelle; A. Santamarina; G. Noguere; O. Litaize; C. Vaglio-Gaudard

doi:doi:10.1051/ndata:07708

All issues

Year: 2007

10.1051/ndata:07708

Abstract

Open Access

Issue		ND 2007 2007


Article Number		228
Number of page(s)		4
Section		Benchmarking for fission applications
DOI		https://doi.org/10.1051/ndata:07708
Published online		17 June 2008

International Conference on Nuclear Data for Science and Technology 2007
DOI: 10.1051/ndata:07708

²³⁹Pu nuclear data improvements in thermal and epithermal neutron ranges

D. Bernard, E. Fort, A. Courcelle, A. Santamarina, G. Noguere, O. Litaize and C. Vaglio-Gaudard

CEA Cadarache, Bd 230, DEN/CAD/DER/SPRC/LEPh, 13108 Saint-Paul-lez-Durance Cedex, France

david.bernard@cea.fr

Published online: 21 May 2008

Abstract
The analysis of k_eff multiplicative factor of 100%-MOx cores and plutonium solutions showed a systematic discrepancy between calculation and experiment. The aim of this paper is to propose an improved version of the JEFF-3.1 ²³⁹Pu evaluation in the low-energy neutron range. We propose here slight modifications of the evaluation file, consistent with the uncertainties of differential data measurements in sub-thermal/thermal and epithermal ranges, namely: modifications of the sub-thermal fission, capture and total cross sections, and a revised evaluation of ν_p from sub-thermal up to 20 eV using a phenomenological formalism. The proposed modifications are described and tested against integral measurements.