A method for quantification of nuclear reactor seismic risk due to design and construction errors based on deficiencies identified in the past

Abstract This paper proposes a plausible methodology for quantification of risk due to seismic related design and construction errors in nuclear power plants. This is based on information available on errors discovered in the past, as reported in construction deficiency reports pursuant to US NRC regulations. Deficiencies found during construction whose recurrence is considered possible are included. The possibility of deficiencies not being discovered is evaluated by comparison of data between operating plants and those under construction. Error consequences are also evaluated from construction deficiency reports; in particular, the impact of errors on the seismic capacity of the plants is quantified by an extension of seismic probabilistic risk assessment (PRA) methods. The application of the method is illustrated based on a limited review of data, showing its capabilities and limitations. Some tentative results are presented, but these by no means represent a formal assessment.