Today at around 9:30 am, 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, 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. (We already
informed on April 2nd, 2011)
Afterward, we implemented sea water sampling at the inside of the pit and
in front of the bar screen near the pit. We made radionuclide analysis
and found radioactive materials (For details to Appendix). Therefore, we
reported to Nuclear and Industrial Safety Agency (NISA), Ministry of
Economy, Trade and Industry (METI), and Fukushima prefecture respectively.
We considered announcing 3 type of nucleus (iodine- 131, cesium-131, and
cesium-137) as definite value at the result of the analysis. In addition,
we will re-evaluate other type of nucleus based on the preventive measures
under a strong warning of NISA on April 1st,
We will implement the countermeasure continuously in order to prevent
radioactive materials influx to the sea from near the pit.
*pit: a shaft made of concrete
Appendix1:The result of the nuclide analysis of the seawater at
the cable pit of Unit 2 and screen(PDF 12.3KB)
Appendix2:Place of Collection (April 2nd)(PDF 227KB)
Appendix3:The result of the nuclide analysis of the seawater at the front
of shallow draft quay and screen of Unit 2, 4(PDF 10.6KB)
Appendix4:Place of Collection (April 3rd)(PDF 434KB)
Appendix5:The result of the nuclide analysis of the seawater at the front
of shallow draft quay and screen of Unit 2, 4(PDF 10.9KB)
Appendix6:Place of Collection (April 4th)(PDF 433KB)
Appendix7:Assumed cause and Tentative planned countermeasure construction
(PDF 31.3KB)
Appendix8:Tentative Preventive Measure of Spreading Radioactive Materials
(PDF 35.3KB)