SuperSafe Reactor&copy

Abstract

A new small modular reactor (SMR) is presented for a 300 MW(e) nuclear generating station, which is referred to as the SuperSafe Reactor© (SSR). The SSR is a smaller version of the Canadian supercritical water-cooled reactor (SCWR), which is designed to operate at supercritical conditions (pressure of 25 MPa and fluid temperatures of up to 625ºC) at the turbine inlet with a high cycle efficiency of greater than 45%.The supercritical turbine technology and associated components used in the balance of plant are similar to and derived from existing supercritical fossil-fired plants. To avoid a large pressure vessel subject to supercritical water pressures and for enhanced safety, the reactor core consists of multiple 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, a ceramic insulator and a fuel bundle assembly. Energy from nuclear fission at normal operating conditions is used to heat the light water coolant to the supercritical state so that very high thermal efficiencies can be achieved. To provide inherent safety, the moderator provides additional cooling to fuel channels under postulated accident scenarios. This design feature also enables the use of a natural circulation flashing-flow driven passive moderator cooling. Another inherent safety feature of the proposed design and a major safety goal is to achieve a passive “no core melt” configuration for the channels and fuel.