Evaluation of Severe External Events on the JSFR

The evaluation of earthquake and tsunami effects on the Japan Sodium-cooled Fast Reactor (JSFR) has been analysed. For seismic design, safety components are confirmed as maintaining their functions even against recent strong earthquakes. As for tsunami, some parts of the reactor building might be submerged, including the component cooling water system (CCWS) whose final heat sink is seawater. However, in the JSFR design, safety grade components are independent of the CCWS. The JSFR emergency power supply adopts a gas turbine system with air cooling, since the JSFR does not basically require quick startup of the emergency power supply owing to the natural convection decay heat removal system (DHRS). Even in the case of extended station blackout, the DHRS could be activated by emergency batteries or manually and be operated continuously by natural convection. (author)