At around 9:30 am on April 2, 2011, 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 flowing out to the ocean. At around 12:20 pm on April 2, we reaffirmed 
the event at the scene. 
We have implemented sampling of the water in the pit of Unit 2, together 
with the seawater in front of the bar screen near the pit of Unit 2. These 
samples were sent to Fukushima Daini Nuclear Power Station for analyses.

At around 5:38 am on April 6, we observed stoppage of spilling of water to 
the ocean from the crack on the concrete lateral of the pit. 

Since April 5 we have been conducting sampling surveys of the water in the 
pit of Unit 2 and the seawater in front of the bar screen near the pit. 
Regarding the survey results of the detection of three nuclides (iodine 131, 
cesium 134, cesium 137), we report those as definite results, and for the 
other nuclides, we will re-evaluate them.

On April 12, due to the installation of silt fences, we changed the 
sampling points from the front of the bar screen of Unit 4 to the north and 
the south of the inside of the water intake canal of Units 1 to 4. Since 
April 17, we have been conducting an additional sampling survey outside the 
silt fence in front of the bar screen of Unit 2, in order to assess the 
effect of the installation of the silt fence.

On May 11, 2011, responding to out-flow leakage of contaminated water from 
the intake canal of Unit 3, from May 12th, we additionally conducted the 
sampling of the seawater inside and outside of the silt fence in front of 
the bar screen near the pit of Unit 1, 3 and 4. 
                                                    (Previously announced)

On June 1, 2011, we conducted sampling of the seawater near the intake 
canal of Units 1 to 4 of Fukushima Daiichi Nuclear Power Station and 
analyzed the samples. As a result, some radioactive materials were detected 
as described in the exhibit. Accordingly, we have reported the result of 
the analyses to Nuclear and Industrial Safety Agency and the government of 
Fukushima Prefecture.

As the result of the analyses for Plutonium238, 239 and 240 about seawater 
sampled on May 16, nothing was detected from the sample.   

We will continue to conduct the same kind of sampling.

* pit: a vertical shaft made of concrete 

Appendix1:The Results of Nuclide Analyses of Radioactive Materials in the 
          Seawater Fukushima Daiichi Nuclear Power Station; the shallow 
          draft quay, Unit 1-4 screen, and the water intake canal of 
          Units 1-4(PDF 17.8KB) 
Appendix2:Result of Pu measurement in the seawater Fukushima Daiichi 
          Nuclear Power Station(PDF 7.91KB)  
Appendix3:Radioactivity Density of Seawater(PDF 44.2KB)