Preliminary conceptual design of the secondary sodium circuit-eliminated JSFR (Japan Sodium Fast Reactor) adopting a supercritical CO turbine system, 1; Sodium/CO heat exchanger

Kisohara, Naoyuki ; Sakamoto, Yoshihiko ; Kotake, Shoji*

JAEA has performed a design study of an S-CO gas turbine system applied to the JSFR. In this study, the S-CO cycle turbine system was directly connected to the primary sodium system of the JSFR to eliminate the secondary sodium circuit, aiming for further economical improvement. The Na/CO heat exchanger is one of the key components, and this report describes its structure and the safety in case of CO leak. A Printed Circuit Heat Exchanger (PCHE) is employed to the heat exchanger. A SiC/SiC ceramic composite material is used for the PCHE to prevent crack growth and to reduce thermal stress. The Na/CO heat exchanger has been designed in such a way that a number of small heat transfer modules are combined in the vessel in consideration of manufacture and repair. CO leak events in the heat exchanger have been also evaluated, and it revealed that no significant effect has arisen on the core or the primary sodium boundary.