System for mitigating the effects of an accident at a nuclear power plant

摘要

A system for mitigating the effects of an accident, such as loss of coolant, at a nuclear power plant, comprising a first container accommodating a nuclear reactor and its primary cooling system, and a second container communicating with the first container to receive and contain the air forced out therefrom as the pressure in the first container rises to an unusally high level as a result of vaporization caused by ebullition of the leaking coolant. In accordance with the invention, the first and second containers communicate through a conduit in which is placed a vapor condenser which is a bubbling device. To prevent the air forced out from the first container from returning thereto, a non-return valve is provided at the inlet to the second container. The first container also accommodates a supplementary condenser of the sprinkler type. Owing to air being forced out from the first container into the second one and vapor condensation in the former, a negative pressure develops, at the initial stage of the accident, in the second container, which is maintained over a long period of time. The occurrence of the negative pressure and its persistence over a long period of time preclude release of radioactive products to the environment.