Press Releases 2014

We inform you the submission of the final report on "Failure report for a nuclear reactor facility for power generation" on the leakage of contaminated water at a tank in the H4 area in Fukushima Daiichi Nuclear Power Station to the Nuclear Regulatory Commission.

[History]
At around 9:50 AM on August 19th, 2013, we found water leakage from a drain valve of a tank dike in the H4 area in Fukushima Daiichi NPS.
At 2:28 PM on the same day, we determined that this incident corresponds to "a case when nuclear fuel material (not in the form of gas) or the like has leaked within an area controlled by the company due to an unpredictable event such as a failure of a nuclear reactor facility for power generation" as per Article 18, item 12 of the regulations concerning the operational safety and the protection of specified nuclear fuel material at the TEPCO's Fukushima Daiichi NPS nuclear reactor facilities for the following reasons:
- Although we have not yet been able to identify the source of contaminated water, water accumulated inside the dike around a tank containing contaminated water has leaked outside the dike through the drain valve.
- It cannot be denied that water stored in a tank has leaked from the tank.
- High β ray and γ ray densities were detected in the puddle of water having leaked outside the dike.

Then, we submitted interim reports about cause and countermeasure for this failure to the Nuclear Regulatory Commission on August 28th, 2013, December 6th, 2013,and June 30th, 2014.