Experience with FRAPCON-2 for the Analysis of CANDU Fuel Performance Under Normal Operating Conditions

Abstract

This paper presents some experience with the LWR code FRAPCON-2 using input data typical of CANDU-600 fuel and a power history typical of an "overpower envelope" as used in CANDU safety analyses. Of the three basic thermo-mechanical model options available, meaningful results were obtained only for FRACAS-I and FRACAS-II, in conjunction with the Booth, Beyer-Hann, and FASTGRASS fission gas release model options. The results are compared with those given by the reference CANDU fuel performance code, ELESIM, for the same input data. In general, the differences between the predictions of the three fission gas release models (for a given thermo-mechanical model) were more pronounced than the differences between the two thermo-mechanical models (for a given fission gas release model). For all combinations of models used, there are some significant differences with respect to the reference results from ELESIM and to known CANDU fuel behaviour. In the light of these disparities, FRAPCON-2 is not recommended for the routine analysis of CANDU fuel performance under normal operating conditions.