NISA indicated that regarding maintenance system for main facilities(seven facilities)^*1 which were needed to maintain the stable cold shutdown of water injection system for reactor pressure vessels and primary containment vessels, some parts of required maintenance plan such as frequency and contents of maintenance has not been formulated. Today we have received an instruction document^*2 from Nuclear and Industrial Safety Agency (NISA) of Ministry of Economy, Trade and Industry. On the inspection in FY2011, NISA pointed out the violation of Chapter 132 (Maintenance) in Safely Regulation on this event.

With this event, NISA indicated as below.

On Chapter 132 of safety regulation, it is ruled that a maintenance method by equipment /facility and a maintenance plan which provides the maintenance method (if necessary, includes preparation of consumables) should be formulated based on the manual.
On the inspection, regarding main facilities(seven facilities) which were needed to maintain the stable cold shutdown of water injection system for reactor pressure vessels and primary containment vessels, it was founded that some parts of required maintenance plan has not been formulated and the management system for consumables and spare parts has had deficiencies. As a result, NISA judged that some of the important process has not been conducted in the maintenance for seven facilities and this event is a violation of safety regulation.

Based on the instruction document, we will further investigate the causes, establish countermeasures to prevent the same kind of errors and report to NISA.

END

*1 Main facility (7 facilities)
(1) Water injection system for reactor pressure vessels and primary containment vessels,
(2) Function of primary containment vessels to prevent a hydrogen explosion
(3) Spent fuel pool,
(4) Injection system of boric acid solution for reactor pressure vessels and primary containment vessels,
(5) High-level concentrated contaminated water decontamination facility, accumulation system (tank), spent sludge storage facility, cesium absorption tower and affiliated facility (transfer pipes, transfer pumps),
(6) Building which high-level concentrated contaminated water accumulates in (including the case of leaked water),
(7) Electrical system.

*2 Instruction document
"Violation of safety regulations in Fukushima Daiichi Nuclear Power Station (instruction)"
(March 15, 2012, NISA, No.4)

*We have provided a Japanese press release version of the instruction document received from NISA. However, at this time we have reserved the right to provide an English version due to potential misunderstandings that may arise from an inaccurate rendering of the original Japanese text. We may provide the English translation that NISA releases in our press releases. However, in principle we would advise you to visit the NISA website for timely and accurate information.