Integrated Functional Modeling Method for Configuring NPP Plant DiD Risk Monitor and its Application for AP1000

A new risk monitor system has been under developing, in order not only to prevent severe accident in daily operation but also even to serve as to mitigate the radiological hazard just after severe accident happens and long term management of post-severe accident consequences. In the proposed risk monitor, the range of risk is not limited to core melt accidents but includes all kinds of negative outcome events, i.e., not only precursor troubles and incident but also any types of hazard states resulting from a severe accident. The whole system of the proposed risk monitor system is configured the by plant Defense-in Depth (DiD) risk monitor and reliability monitor, and in this paper the result of how to configure the Plant Defense in-Depth Risk Monitor by functional modeling approach is first presented. Then, a preliminary study is conducted on applying the integrated functional modeling for Plant Defense-in-depth risk monitor for passive safety system of AP1000.