Conceptual containment venting strategy for Susquehanna steam electric station

To mitigate the consequences of postulated BWR reactor accidents, generic industry guidance for venting the primary containment has been proposed to prevent catastrophic containment failure, maintain low pressure vessel injection capability, and/or remove combustible gas which may cause containment failure if ignited. Detailed analysis of the generic guidance shows that such venting must not be performed irrespective of off-site consequences. The decision to vent must be made with an evaluation of the off-site consequences. The conclusion of this paper is that venting without a source term or with a limited source term is permissible, either to maintain core cooling or to preserve the containment function for the future. However, with a large potential source term, such as would result from severe core melt and relocation, venting is not an effective risk management policy and maintenance of "containment" is paramount. This paper reviews the generic venting approach, the reasoning behind the generic approach, and presents a conceptual venting strategy for the Susquehanna Steam Electric Station (SSES) in light of PP and Lʹs (formerly Pennsylvania Power and Light, Co.) own severe accident analysis experience.