Application of Realistic Thermal-Hydraulic Methods for Pressurized Water Reactors with Upper Plenum Injection

Calculations were performed using a best-estimate computer code that determined the estimates of the 50th percentile peak cladding temperature (PCT) (1006 K) and the 95th percentile PCT (1263 K). These calculations included realistic WCOBRA/TRAC predictions of thermal-hydraulic phenomena occurring inside the vessel during upper plenum injection (UPI). The work done in applying realistic thermal-hydraulic methods for pressurized water reactors (PWRs) with UPI represents an important step in the maturation of advanced best-estimate computer codes like WCOBRA/ TRAC because their effect is finally being used in the licensing of operating plants, and their benefits are being used to make those PWRs more flexible and economic to operate.