This is follow-up information regarding the water leak from a drain valve of a tank dike in the H4 area in Fukushima Daiichi NPS.
At 2:28 PM Today (on August 19), 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.
The reasons for the determination are as follows:
-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.
We will explain this incident in the press conference to be held this evening.