A framework to determine the holistic multiplier of performance shaping factors in human reliability analysis – An explanatory study

The safety of nuclear power plants is the uppermost goal to be emphasized for their sustainability. To this end, it is crucial to evaluate their anticipated risk by visualizing accident scenarios resulting in undesirable consequences. In quantifying the likelihood of an accident scenario occurrence, it is necessary to estimate values of human error probabilities with respect to the performance of safety-critical tasks following relevant human reliability analysis (HRA) methods. One of the technical issues pertaining to the quality of HRA results is to determine the multipliers of performance shaping factors (PSFs) that specify the contexts in which human operators have to accomplish the required safety-critical tasks. Unfortunately, since PSFs are entangled with complicated interrelations, it is hard to properly determine their multipliers. To address this problem, in this study, a framework that can quantify the holistic multiplier of a specific PSF is proposed that can encompass the effect of these complicated interrelations. In order to corroborate the applicability of the proposed framework, an explanatory case study is conducted by using data available from the literature. Based on the result of this case study, it is expected that the proposed framework would be effective for determining PSF multipliers.