Consideration on rationalization of reactor safety systems; evaluation of impact to plant safety and operations against facility sharing

Chikazawa, Yoshitaka  ; not registered; Nishiguchi, Yohei; Konomura, Mamoru

In the Feasibility Study of JNC, sodium cooled large-scale fast reactor and medium-scale modular reactor are studied as two of promising concepts. Sodium cooled medium-scale modular reactor has disadvantage compared to large-scale reactor that has large-scale effect. To compensate the disadvantage, modular effects are facilitated to improve facility sharing among modules, learning effect and so on. But facility sharing makes the plant system complex and impacts to plant safety and operations are worried. We evaluated the impacts to plant safety and operations by facility sharing in sodium cooled medium-scale modular reactor. We arranged ideas of facility sharing and extracted four ideas which are considered to have big impacts to safety or operations. (1)Sharing of the central control room (2)Reduction of emergency generators (3)Adoption of large capacity turbines (4)Sharing of auxiliary cooling water system In this study, we evaluated impacts to safety operability, annual inspection and availability under consideration of the risk for unscheduled shutdown against above four facility sharing plans. Consistency of the facility sharing was confirmed.