Fukushima Daiichi NPS Prompt Report 2013

This is follow-up information regarding the water leak from the underground reservoir No. 2 in Fukushima Daiichi NPS.

At 5:43 am on April 6, we started transferring the water from the underground reservoir No. 2 to the underground reservoir No. 1.

At 5:43, we conducted an on-site survey and confirmed that there is no abnormality such as leakage on the transferring line.

We assume that amount of the leaked water is approx. 120 m³, the whole γ radioactive concentration is approx. 1.5 x 10⁰ (Bq/cm³), the whole β radioactive concentration is approx. 5.9 x 10³ (Bq/cm³), the whole amount ofγradioactivity is approx. 1.8 x 10⁸ (Bq) and the whole amount of β radioactivity is approx. 7.1 x 10¹¹ (Bq). We are conducting further investigations on this matter.

We judged that this incident can be applied mutatis mutandis pursuant to Paragraph 10 of Article 19 (17) of Regulations Concerning the Installment, Operation, etc. of Reactors that stipulates "when radioactive material leakage found in controlled area due to accident or other contingency situations" at 5:10 am on April 6, even though it is occurred outside of the controlled area.

Therefore, this report has been issued in accordance with the Article 168 of Safety Standard for Nuclear Facilities of Fukushima Daiichi Nuclear Power Station (Reports).