iB1350 no2. Level 1 PRA for optimization of safety systems of the iB1350

Crediting the iB1350 (innovative, intelligent, and inexpensive BWR 1350) reactor's passive safety systems in DBA analyses allows optimization of its overall safety system configuration. This paper compares the 2 new optimized configurations described in the series paper no.1 for the iB1350 in ICAPP2017 and they are expected to enhance safety and reliability while reducing cost from the original design. Safety system configuration can be further optimized since the iB1350's innovative passive containment cooling system (iPCSS) has greater decay heat removal capability than the conventional PCCS. While the conventional PCCS cannot cool the suppression pool, the iPCCS can. This makes it possible to cool the core and the containment using only core injection systems and the iPCCS without the conventional active RHR systems. The iPCCS can replace some of the conventional active RHR systems. Additionally, divisions without RHR systems can use a dedicated air-cooled component cooling system and a gas turbine generator rather than a reactor sea water cooling system and a diesel generator. This optimization enhances system and power diversity. To analytically compare these safety system configurations, a Level 1 Internal Events Probabilistic Risk Assessment (PRA) has been performed for each configuration. While the two optimized configurations each remove two RHR systems, crediting iPCCS and enhanced power diversity result in excellent performance for the overall CDF. (author)