ABSTRACT
This paper will describe the approach being taken in several areas of the reactor and the spent fuel pool Level 2 PSA to promote realism in the treatment of the overall site risk. Specifically, the following sections describe the modeling approach in the areas of structural failure characterization, severe accident phenomena, survivability of equipment and instrumentation, and severe accident management. In each section, examples are given where realistic treatment leads to better estimation of site-wide accident interactions. In addition to the interplays between radiological sources within a given modeling area, the paper will also point out
1 INTRODUCTION
The United States Nuclear Regulatory Commission (US NRC) is developing a site Level 3 Probabilistic Safety Analysis (PSA) for the two operating nuclear power plants, and associated spent nuclear fuel storage facilities at the Vogtle site in Georgia, USA. In nuclear power plant risk assessment terminology, Level 3 refers to the modeling of accidents from their initiation to the offsite consequences caused by the accidents (public health effects and property damage). The scope of the Vogtle Level 3 PSA is events caused by both internal and external hazards, excluding acts of sabotage. The development of this integrated (a.k.a., extended) PSA, along with its intended end-uses, shifts the focus in the Level 2 (accident progression and radiological source term) portion of the analysis toward greater realism.
