On April 13, 2011, we received a directive document^* "Collection of Reports Pursuant Article 67 Clause 1 of the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors" from the Nuclear and Industrial Safety Agency (NISA) of the Ministry of Economy, Trade and Industry. (Previously announced on April 13, 2011)

In accordance with the direction given, we investigated on the current seismic safety and reinforcement of Unit 1 and 4 Reactor Buildings at Fukushima Daiichi Nuclear Power Station and submitted the results to NISA. (Previously announced on May 28, 2011)

As debris removal from the upper part of Unit 4 Reactor Building has almost been completed, the loading condition was reviewed and the design outline of the fuel handling machine structure to be installed in Unit 4 was determined accordingly. The seismic safety evaluation results taking into considerations these updates were submitted to NISA. (Previously announced on August 30, 2012)

Since it was found that a part of the analysis data of Unit 4 Reactor Building included in the report was incorrect, correction was made and reanalysis was done while reviewing the entire data. We have submitted a report addressing the cause of this issue and recurrence prevention measures to the Nuclear Regulatory Authority today.

Attachment
"Report on the Current Seismic Safety and Reinforcement of Reactor Buildings at Fukushima Daiichi Nuclear Power Station (No.1) (Supplement) (Revision)" (PDF 3.13MB)

* Directive document
"Collection of Reports Pursuant Article 67 Clause 1 of the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors" (April 12, 2011)

The aforementioned documents are available only in Japanese. We apologize for the inconvenience this may cause.