Treatment of Cross Section Uncertainties in the Transport Monte-Carlo Code TRIPOLI4

Abstract

The object of this paper is to present how perturbation techniques implemented in TRIPOLI-4 can be used to treat the uncertainties on nuclear data. The perturbation scheme used in these calculations is the correlated sampling method. Cross sections uncertainties are processed in multigroup mode via the modules GROUPR and ERROR of NJOY nuclear data processing system. We use the relative error output of the Error module. Perturbated cross sections are then sampled according to the covariance matrix. The perturbation scheme is used to obtain the perturbated score corresponding to these cross sections. This procedure is repeated to obtain an estimation of the dispersion of the response due to the cross section variations. This dispersion is a measure of the effect on the result of uncertainties on the cross sections. This method is demonstrated by application to the Winfrith Iron Benchmark.