At around 9:30 am on April 2nd, we detected water containing radiation
dose over 1,000 mSv/h in the pit* where supply cables are stored near the
intake channel of Unit 2. Furthermore, there was a crack about 20 cm on
the concrete lateral of the pit, from where the water in the pit was out
flowing. 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. (Reported on April
2nd already)
Today at 5:38 am, we have 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 will also
note the water level of turbine building of unit 2 remain unchanged. We
will further investigate if there is any other leakage. (Reported on April
6th already)
We have been conducting sampling of seawater in front of the bar screen
near the pit. In regard to the sample collected yesterday (April 5th), as
a result of conducting nuclide analysis, radioactive materials were
detected as described in the exhibit. Accordingly, we have reported the
result of analysis to Nuclear and Industrial Safety Agency and Fukushima
Prefecture.
Regarding the results on three nuclides (iodine 131, cesium 134, cesium
137), we would like to assume those as definite result, however, as for
other nuclides, we will revaluate in accordance with the preventive
measures formulated after being given warning from Nuclear and Industrial
Safety Agency on April 1st.
* pit: a shaft made of concrete
Appendix:Results of nuclide analysis on seawater sampled in front of quay
and screens of Unit 2/4(PDF 9.88KB)
Appendix:Radioactivity density of seawater near the quay of Fukushima
Daiichi Nuclear Power Station (PDF 12.2KB)