Assessment of the limits of magnitude–frequency relationship change for the development of risk-oriented safety regulation of nuclear power plants: A case study for some regions of the East European and North American platforms

Abstract

Catastrophic earthquakes on platforms determine the relevance of the development of criteria for the identification of locations and assessment of the intensity and frequency of such events. The low accuracy of data on historical earthquakes and the short series of instrumental observations, as well as the lack of representative statistics, lead to mixed assessments of seismic hazards using deterministic and probabilistic methods and complicates the risk-oriented safety regulation of nuclear power plants (NPP). In order to solve this problem, we propose a method for the assessment of the expected magnitude—frequency relationships based on the uniform model of the Earth’s crust, taking into account the dependence of earthquake limiting magnitudes on the strain conditions, size, and type of the source (Bugaev and Spivak, 2002; Bugaev, 2011). The uniform model of the Earth’s crust reflects discrete properties of the Earth’s crust, including earthquake sources and the areas of their nucleation (for example, see (Sadovskii, 1979) and others). In (Bugaev, 2014), the method is considered in relation to the assessment of expected magnitude—frequency relationships of the seismically active area. In this paper, the method is used to assess magnitude—frequency relationships, taking into account the geodynamic and seismic conditions of some areas of the East European (EEP) and North American (NAP) platforms. The similarities and differences of the magnitude—frequency relationships that define the long-term and current seismic hazard for the EEP and NAP are found. In particular, it is pointed out that it is relevant to set criteria for when recommendations should be issued for the implementation of organizational and technical NPP security measures, based on the results of seismological monitoring.