Safety Analysis for PHTS Integrity by the failure of the IHTS function in PGSFR

In this paper, the failure of the heat removal function of the IHTS by the SWR event is assumed. The integrity of the PHTS is analyzed by MARS-LMR code. A sodium is used as a reactor coolant to transfer the core heat to the turbine. It rigorously reacts with a water or steam in chemical and generates the high pressure waves and high temperature reaction heat. While it has an excellent characteristics as a coolant, there is an event to be necessarily considered in the sodium cooled fast reactor design. The Sodium-Water Reaction(SWR) event can be occurred due to the rupture of steam generator tubes. This event threaten the integrity of the Primary Heat Transfer System(PHTS). It is categorized to the loss of heat sink events, which are undercooling the Primary Heat Transfer System(PHTS). In PGSFR, the SWR event can be occurred in the SG. The PHTS is analyzed to the respects of the integrity of the fuel and cladding using the MARS-LMR code. From the analysis results, the peak temperature of the fuel and cladding have a sufficient margin to the safety acceptance criteria 1,237 .deg. C and 1,075 .deg. C, respectively