Design, fabrication and installation of primary heat transport system for prototype FBR development

The design study of the heat transport system for 300 MWe class FBR based; on the experience of MONJU is described here. The heat transport system is composed of three loops, based on the single failure criterion, that is, the decay heat after reactor trip can be removed by at least one heat transport system with the consideration of subsequent loss of any safety equipment. The sodium is used as a coolant for FBR, and is in liquid-phase without pressuring it. So, it needs not to consider the depressurizing, boiling even at the unexpected pipe rupture accident. The piping system in the primary heat transport system is designed with the consideration of the unexpected pipe rupture, therefore nearly all the primary piping is arranged in layout to be placed in a high position and some of the piping together with components are equipped with the guard vessel, to keep the sodium above a certain level for securing the core coolability