Nuclear safety culture has been one of the most important aspects for safe and reliable operations of nuclear power plants worldwide.
Promoting nuclear safety culture has been a very important task for Japanese nuclear operators since 2007, when it was included in the Safety Regulations. Nuclear safety culture has some important aspects such as understanding of own culture, voluntary actions, a trial and error approach, etc. Among them, detection of the symptoms of weakening safety culture is the most important activity to maintain good safety culture. Chubu Electric Power Co. (Chubu) has been trying to detect the symptoms using three indicators since April, 2009. Those indicators are results of questionnaire, number of nonconformities and Root Cause Analysis (RCA) results. We have two types of lamp in detecting weakening safety culture, yellow and red for each element of safety culture. Those elements are “compliance”, “communication”, “technical ability” and “morale and enthusiasm”. We have found that those indicators have worked well in making alarm to Chubu’s nuclear personnel. We are now trying to improve those indicators and to strengthen countermeasures in the case of detecting weakening safety culture.