Use of International Criticality Safety Benchmark Evaluation Project Benchmarks for the Validation of CSAS26 (Scale 4.4a) for Configurations of Low-Enriched Uranium

Abstract

As an example of the application of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) work to the nuclear industry, the validation of the control module CSAS26 of SCALE 4.4a for criticality calculations on a personal computer platform is presented. This work has been done using the models of critical experiments being compiled by the Organisation for Economic Co-operation and Development/Nuclear Energy Agency (OECD/NEA) since 1992. The description and results of this compilation were first presented during the Fifth International Conference on Nuclear Criticality Safety (ICNC’95). Out of 2881 critical configurations included in the latest edition (September 2002) of the ICSBEP “International Handbook of Evaluated Criticality Safety Benchmark Experiments,” NEA/NSC/DOC(95)03, OECD/NEA, 131 have been selected for the CSAS26 validation. The selected critical experiments have characteristics similar to the systems to be simulated with CSAS26 for low-enriched uranium (LEU) fuel fabrication applications. They represent both homogeneous configurations and hexagonally pitched rod lattices of low-enriched (from 1.60 to 5.00 wt% 235U) UO2 with several absorbers. The statistical uncertainties related to the application of CSAS26 for criticality calculations are also evaluated. The great number of cases involved allows an exhaustive statistical treatment of the data, including the analysis of correlations related to the type of system being simulated. The statistical uncertainties found are very small. As a result, the module CSAS26 is considered as a quite suitable calculational method for application to criticality safety analysis at LEU facilities.