The next-generation risk assessment method about the effect of a slope and foundation ground on a facility in a nuclear power plant

From the background of the accident of the nuclear power plant caused by The 2011 off the Pacific coast of Tohoku Earthquake, the view about the effect of ground such as a slope and a foundation on the nuclear power plant in not only the regulatory guidance for seismic design but also the standard about seismic probabilistic safety assessment was also revised remarkably in JAPAN. A view of the limit state to evaluate the fragility curve about the effect of a slope failure on the facilities described in the latter standard was improved by geotechnical approach such as considering the dynamic behavior of geomaterials after collapse. The view should be called the next-generation assessment about slope stability. The limit state regarding on the slope failure on the facility was specified based on an experimental consideration. Here, the view is reported with experimental results obtained from shaking table tests and its numerical analysis. The experimental examples are also described to verify the effect of countermeasure against the seismic action exceeding the limit state. As a examples to evaluate the movement of rock block induced by slope collapse, the numerical method and its example of application were also described.