International Conference on Nuclear Data for Science and Technology 2007
DOI: 10.1051/ndata:07629

Evaluation of tungsten isotopes in the fast neutron range including cross section covariance estimation

R. Capote¹, A. Trkov², I. Kodeli³, E. Soukhovitskii⁴, L.C. Leal⁵, M. Herman⁶ and D.W. Muir<sup>7

1</sup>  Nuclear Data Section, International Atomic Energy Agency, 1400 Vienna, Austria
²  Jozef Stefan Institute, Ljubljana, Slovenia
³  International Atomic Energy Agency representative at the OECD/NEA Data Bank, 92 130 Issy-les-Moulineaux, France
⁴  Joint Institute for Energy and Nuclear Research, 220109 Minsk-Sosny, Belarus
⁵  Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6356, USA
⁶  National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY, USA
⁷  International Atomic Energy Agency (Consultant), P.O. Box 452, Kittery, Maine, USA

Andrej.Trkov@ijs.si

Published online: 21 May 2008

Abstract
New evaluations for the tungsten isotopes ^{180,182,183,184,186}W in the neutron energy range up to 60 MeV were produced. In the resonance range only minor adjustments to the resonance parameters were made due to a lack of adequate experimental data. Evaluations in the fast energy region were based on nuclear model calculations using the EMPIRE-2.19 code. Recently derived dispersive coupled-channel optical model potentials for W and Ta isotopes were instrumental to achieve a very good description of the available microscopic cross section database. Model covariance data were generated with the Monte Carlo technique to produce a prior estimate for the covariance matrix. Experimental data were introduced through the GANDR system. The evaluated files were tested on selected fusion neutronics benchmarks and showed marked improvement compared to other existing evaluations.

© CEA 2008