BWR loss-of-coolant accident analysis capability of the WRAP-EM system

The modular computational system known as the Water Reactor Analysis Package (WRAP) has been extended to provide the computational tools required to perform a complete analysis of LOCAs in BWRs. The new system is known as the WRAP-EM (Evaluation Model) system and will be used by NRC in interpreting and evaluating reactor vendor EM methods and computed results. The system for BWR-EM analysis is comprised of several computer codes which have been developed to analyze a particular phase of a LOCA. These codes include GAPCON for calculation of initial fuel conditions, WRAP (the previously developed SRL analog of RELAP4/MOD5) for analysis of the system blowdown, NORCOOL for analysis of the reflood phase, and MOXY for the calculation of the fuel assembly hot plane temperature. In addition, a BWR steady-state initialization procedure has been developed to provide the initial operating state of the reactor system. The BWR-EM system is operational and is currently being evaluated to determine the adequacy and consistency of the physical models employed for EM analysis