Advanced liquid-metal reactor IHX protection from a severe sodium/water reaction event

The US program for development of an advanced liquid-metal reactor (ALMR) is proceeding into a significant new phase of focused design development utilizing a national team under US Department of Energy sponsorship. A project goal is to demonstrate by full-scale testing the safety features of one reactor module, thereby providing the technological basis for design certification by the US Nuclear Regulatory Commission. The reference design for the 1395-MW(electric) plant utilizes three 465-MW(electric) power blocks. Each power block, representing the basic building block in the ALMR concept, consists of three identical 471-MW(thermal) reactor modules located below grade, each with its own steam generator (SG) system, which are headered into a common turbine generator. One of the innovative features of the ALMR is the manner in which the SG and associated interfacing systems have been configured to provide assured protection of the intermediate heat exchanger (IHX) tubes from a worst-case SG tube leak and resulting sodium/water reaction event. For this event, it is assumed that, despite the very low probability of occurrence, all the tubes in the SG fail and the steam-side isolation and blowdown system fails to function and terminate the event. This paper describes a design approach to ensure protectionmore » against this highly unlikely event.« less