New Opening Strategy of Filtered Containment Venting System

Abstract

Filtered containment venting system (FCVS) is used in some nuclear power plants to avoid containment overpressure failure and uncontrolled radioactive release in severe accidents. Currently the opening strategy is mainly based on the containment pressure, such as the design pressure. The containment has a stronger capability. There are various deposition mechanisms or even plugging of aerosol particles passing through potential micro channels within the containment. There are various natural or engineered deposition mechanisms of aerosol particles in the containment. The qualification pressure of FCVS can be increased. If the FCVS is opened later, the total radioactive release into the environment can be decreased, even though the leakage may be increased. A new opening strategy of FCVS is proposed, which is not just based on the containment pressure, but considers the containment capability, various deposition mechanisms or even plugging of aerosol particles passing through potential micro channels within the containment, various natural or engineered deposition mechanisms of aerosol particles in the containment. This strategy uses the radioactive release into the environment and associated radiological consequence as the optimization objective, considering both radioactive release through potential micro channels before venting and radioactive release after venting, and can reduce the radioactive released into the environment as far as possible while maintaining the integrity of the containment.