Comparison of nuclear data uncertainty propagation methodologies for PWR burn-up simulations. (March 2015)

• Record Type: Journal Article
• Authors: Díez, C.J.; Buss, O.; Hoefer, A.; Porsch, D.; Cabellos, O.
• Is Part Of: Annals of nuclear energy. Volume 77(2015:Mar.)
• Page Start: 101
• Page End: 114
• Publication Date: 2015-03
• Subjects: Uncertainty quantification -- Burn-up -- PWR -- Nuclear data uncertainties -- NUDUNA -- Hybrid Method; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2014.10.022
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: Comparison of methodologies for propagating nuclear data uncertainties in burn-up. Influence of nuclear data uncertainties: ENDF/B-VII.1 versus SCALE6.0 covariances. Nuclear data uncertainty assessment for a PWR fuel pin-cell burn-up with ENDF/B-VII.1. Effect of neglecting isotopic number density uncertainties in burn-up simulations. Effect of neglecting neutron flux and spectrum uncertainties in burn-up simulations. Abstract: Several methodologies using different levels of approximations have been developed for propagating nuclear data uncertainties in nuclear burn-up simulations. Most methods fall into the two broad classes of Monte Carlo approaches, which are exact apart from statistical uncertainties but require additional computation time, and first order perturbation theory approaches, which are efficient for not too large numbers of considered response functions but only applicable for sufficiently small nuclear data uncertainties. Some methods neglect isotopic composition uncertainties induced by the depletion steps of the simulations, others neglect neutron flux uncertainties, and the accuracy of a given approximation is often very hard to quantify. In order to get a better sense of the impact of different approximations, this work aims to compare results obtained based on different approximate methodologies with an exact method, namely the NUDUNA Monte Carlo based approach developed by AREVA GmbH. In addition, the impact of different covariance data is studied by comparing two of the presently most complete nuclear data covariance libraries (ENDF/B-VII.1 and SCALE 6.0), which reveals a high dependency of the uncertainty estimates on the source of covariance data. The burn-up benchmark Exercise I-1b proposed by the OECD expert group "Benchmarks for Uncertainty Analysis in Modeling (UAM) for the Design, Operation and Safety Analysis of LWRs" is studied as an example application. The burn-up simulations are performed with the SCALE 6.0 tool suite.