原子力発電所における非正常時対応行為からのポジティブな教訓導出手法の構築

抄録

Nuclear operators have considered past troubles as failures and have taken measures to prevent their recurrence by eliminating the causes of such failures. Although these measures have contributed to improving nuclear safety, it is insufficient to strengthen them to improve safety further; a new perspective on safety is required. On the basis of the Safety-II concept, many troubles that did not result in significant harm can be regarded as instances where human actions have successfully contributed to avoiding undesirable harm. Safety can be further enhanced by focusing on human actions during such troubles and utilizing them as learning opportunities to encourage positive actions. Currently, however, the nuclear industry must still establish a systematic and practical method for learning positive lessons. In this study, we organized resilience potentials and human actions against off-normal events in nuclear power plant operations. A positive lesson learning method utilizing 11 categories of human action derived from this organization was proposed. The proposed method was applied to 96 manual shutdown events at Japanese PWRs. These analyses confirmed the sufficiency of the 11 categories in the analysis flow of the proposed method and the effectiveness of the resulting safety improvement measures in terms of Safety-II.