Pathways and Uncertainty Prediction in Fispact-II

Culham Electromagnetics Ltd, Culham Science Centre Abingdon OX14 3DB, United Kingdom

Abstract

This paper describes how the new inventory code Fispact-II provides predictions of radiological quantities and their uncertainties using TENDL data. Central to the method is a novel fast pathways search algorithm using directed graphs. The pathways output provides (1) an aid to identifying important reactions, (2) fast estimates of uncertainties, (3) reduced models that retain important nuclides and reactions for use in the code’s monte-carlo sensitivity analysis. Described are the methods that are being implemented for improving uncertainty predictions using the covariance data that the recent TENDL nuclear data libraries contain.