A Supercritical Water-Cooled Small Modular Reactor

A new small modular reactor (SMR) is proposed for a 300 MW(e) nuclear generating station. It is referred as the SuperSafe© Reactor (SSR) and is a scaled down version of the Canadian supercritical water-cooled reactor (SCWR), which is designed to operate at supercritical conditions (pressure of 25 MPa and fluid temperature of 625°C) at the turbine inlet with high cycle efficiencies (∼45%). The supercritical turbine technology and associated components used in the balance of plant (BOP) are similar to those in existing supercritical fossil-fired plants. The reactor core consists of fuel channels, which are submerged in a subcooled heavy-water moderator pool inside a low-pressure calandria vessel. Each fuel channel consists of a pressure tube and a ceramic insulator enclosed inside a porous stainless steel sleeve. The moderator provides cooling to fuel channels under normal operation and postulated accident scenarios. This design feature enables the use of a flash-driven passive moderator cooling — an inherent safety feature of the proposed design. A major safety goal is to achieve a passive “no core melt” configuration for the channels and fuel.