Study of electrical instrumentation and control equipment malfunction events in nuclear power plants

Electrical instrumentation and control equipment plays an important role in safety and efficient operation of nuclear power plants: In this report, malfunction events on electrical instrumentation and control equipment of nuclear power plant were analyzed using the database in Japan and the United States, examined relevant documents, and studied measures for preventing recurrence of similar events. First, to help this analysis, the database of malfunction events on electrical instrumentation and control equipment has been structured from Licensee Event Reports (LER) in the United States and accident reports to the Ministry of International Trade and Industry of Japan. Second, by utilizing the database, the causes of each event were analyzed and evaluated. Consequently, as it is clarified that testing detected malfunction in many events testing should be focused and evaluated in further research from the point to level off the work load and shorten the refueling outage period. Based on this analysis, seven measures have been studied to improve facilities for the prevention of recurrence of accidents. (author)