Press Releases 2013

At around 8:05 PM on October 2, 2013, a TEPCO employee found a water dropping from around the top plate of B area (south) tank (No.5 tank at Group A in B area), while he was working in that area for the purpose of treating the accumulated water inside the dike at B area (south), where treated water from the desalination apparatus is stored in the tanks, at Fukushima Daiichi NPS.

At 9:55 PM on the same day (on October 2), after examining the situation at the site, we found that the leaked water was not only dropping inside the dike, but also dropping to outside of the dike via the scaffold installed around the tank for inspection.

Therefore, 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.

We analyzed the leaked water (sampled at 3:00 PM on October 2), and the measurement results were as follows.
- All-β: 200,000Bq/L (by a simplified measurement method)
- Cesium-134: 18Bq/L
- Cesium-137: 54Bq/L

After further investigation, we determined that it cannot be denied that the water leaked from the top plate of the tank flowed into the drainage (the drainage channel C) via the side ditch nearby, and leaked into the sea. Therefore, we performed water-stop measures by putting sandbags in the side ditch which connects to the drainage channel C.

We sincerely apologize to the residents nearby and broader society for the extreme anxiety and inconvenience caused by this matter.