At around 9:30 am on April 2nd, we detected water containing radiation 
dose over 1,000 mSv/h in the pit* where power supply cables are stored 
near the intake channel of Unit 2. Furthermore, there was a crack of 
about 20 cm length on the concrete lateral of the pit, from where the 
water in the pit was outflowing. At around 12:20 pm on April 2nd, we 
reaffirmed the event at the scene.
We have implemented sampling of the water in the pit, together with the 
seawater in front of the bar screen near the pit. These samples were sent 
to Fukushima Daini Nuclear Power Station for analysis.

At around 5:38 am on April 6th, we observed stoppage of spilling of water 
from the crack on the concrete lateral of the pit. For the sake of 
completeness, we put further reinforcement for the stoppage of leakage and 
consider countermeasure including continuous injection of coagulant. We 
have also confirmed the water level of the turbine building of unit 2 
remains unchanged. We will further investigate if there is any other 
leakage.

Since April 5th we have been conducting sampling of seawater in the pit 
and in front of the bar screen near the pit. Regarding the results on 
three nuclides (iodine 131, cesium 134 and cesium 137), we would like to 
assume those as definite result, but, as for other nuclides, we will 
revaluate in accordance with the preventive measures formulated after the 
warning from Nuclear and Industrial Safety Agency (NISA) on April 1st.
                                                   (previously announced)

Since April 12th, 2011, due to the installment of the silt fence, we have 
changed sampling sites to the north and south sides of the water intake 
canal of Unit 1 to 4 from that in front of the bar screen of Unit 1 to 4.

On April 13th, 2011, we collected samples from seawater in the pit and in 
front of the bar screen near the pit. As a result of the nuclide analyses, 
radioactive materials were detected as described in the exhibit. 
Accordingly, we have reported the result of the analysis to NISA and the 
government of Fukushima Prefecture.

* pit: a vertical shaft made of concrete 

Appendix: Result of Nuclide Analysis of the seawater at the shallow draft quay, 
          Unit 2 screen and the water intake canal of Unit 1-4 (PDF 10.4KB) 
 
Appendix: Radioactivity density of seawater near the quay of Fukushima 
          Daiichi Nuclear Power Station (PDF 36.5KB)