Physical Aspects of the Canadian Generation IV Supercritical Water-Cooled Pressure Tube Reactor Plant Design

Abstract

Canada is developing a next generation (Gen IV) reactor, the Canadian Super-Critical Water-cooled Reactor (SCWR), which has the potential of meeting all design goals of the Gen IV International Forum (GIF). These goals include inherent safe operation and deploying passive safety features, improved economic and resource utilization, enhanced sustainability, and greater proliferation resistance compared to the current fleet of reactors. The form of the containment building is a function of the requirements imposed by various systems. In order to provide sufficient driving force for naturally-circulated emergency cooling systems, as well as providing a gravity-driven core flooding pool function, the Canadian SCWR relies on elevation differences between the reactor and the safety systems. These elevation differences, required volumes of cooling pools and the optimum layout of safety-related piping are major factors influencing the plant design. As a defence-in-depth, the containment building and safety systems also provide successive barriers to the unplanned release of radioactive materials, while providing a path for heat flow to the ultimate heat sink, the atmosphere. Access to the reactor for refuelling is from the top of the reactor, with water used as shielding during the refuelling operations. The accessibility to the reactor and protection of the environment are further factors influencing the plant design. This paper describes the physical implementation of the major systems of the Canadian SCWR within the reactor building, and the position of major plant services relative to the reactor building.