Application of FORSS Sensitivity and Uncertainty Methodology to Fast Reactor Benchmark Analysis

摘要

FORSS is a code system used to study relationships between nuclear reaction cross sections, integral experiments, reactor performance parameter predictions, and associated uncertainties. This paper presents the theory and code description as well as the first results of applying FORSS to fast reactor benchmarks. Specifically, for various assemblies and reactor performance parameters, the nuclear data sensitivities were computed by nuclide, reaction type, and energy. Comprehensive libraries of energy-dependent coefficients have been developed in a computer retrievable format and released for distribution by RSIC and NNCSC. Uncertainties induced by nuclear data were quantified using preliminary, energy-dependent relative covariance matrices evaluated with ENDF/B-IV expectation values and processed for exp 238 U(n,f), exp 238 U(n, gamma ), exp 239 Pu(n,f), and exp 239 Pu( nu ). Nuclear data accuracy requirements to meet specified performance criteria at minimum experimental cost were determined. (ERA citation 02:019779)