Material Performance of Fully-Ceramic Micro-Encapsulated Fuel Under Selected LWR Design Basis Scenarios: Final Report.

摘要

The extension of the use of Deep-Burn (DB) coated particle fuel envisaged for use in High Temperature Reactors (HTRs), to existing Light Water Reactors (LWRs) has been investigated. In this case the TRISO coated fuel particles are used in Fully-Ceramic Microencapsulated (FCM) fuel within a SiC matrix rather than the graphite matrix typically used in HTRs. TRISO fuel particles have been well characterized for uranium fueled HTRs. However, LWRs exhibit different operating conditions as compared to HTRs in terms of temperature, neutron energy spectrum, fast fluence levels and power density. Furthermore, the time scales of transient core behavior during accidents are in general much shorter in LWRs. The Particle STress Analysis (PASTA) code has been updated to allow for the stress analysis of coated particle FCM fuel. The code extension enables the automatic use of the neutronic data (burnup, fast fluence as a function of the irradiation time) that is generated with the DRAGON neutronics code. Furthermore, an input option for automatic evaluation of a temperature increase during anticipated transients has been added to the code. A new thermal model for FCM was incorporated in the code, as well as updated correlations for the pyrocarbon coating layers that can estimate dimensional change at the high fluence levels attained in LWR DB fuel.