SBWR ATWS mitigation by boron injection

Automatic boron injection by a standby liquid control system (SLCS) is one of several safety features of the Simplified Boiling Water Reactor (SBWR) designed by General Electric for mitigation of anticipated transients without scram (ATWS). The RAMONA-4B code being developed at Brookhaven National Laboratory (BNL) for the SBWR has been used to evaluate the performance of the SLCS boron injection for the mitigation of a main steam isolation valve (MSIV) closure ATWS, using 3D neutron kinetics with a detailed bundle-by-bundle representation for both thermohydraulics and neutronics. This analysis shows that the SBWR SLCS boron injection is more effective than that for the current BWRs for shutting down the reactor due to the increased boron injection rate and the use of 94% enriched B10 isotope in the 12.5% sodium pentaborate solution. (author)