Discharge of low level radioactive accumulated water in
the Fukushima Daiichi Nuclear Power Station to the sea


Press Release Apr 04, 2011

There is currently great amount of radioactive waste water in the turbine buildings of the Fukushima Daiichi Nuclear Power Station and especially the turbine building of Unit 2 has extremely high level radioactive waste water.

We think it is necessary to transfer the radioactive waste water to the Central Radioactive Waste Disposal Facility in order to store it in a stable condition. However, ten thousand of low level radioactive waste water has been already stored and we have to discharge the existing low level radioactive waste water to receive new liquids.

In addition, as low radioactive subsurface water is piling up in sub-drain pits of Unit 5 and 6 and a part of subsurface water is running into buildings, we are concerned that important equipment to secure the safety of reactors will be submerged.

Based on the Section 1 of the Article 64 of the Nuclear Reactor Regulation Law, we have decided to discharge to the sea approximately ten thousand tons of the accumulated low level radioactive water and a total of 1,500 tons of the low level radioactive subsurface water stored in the sub drain pits of Unit 5 and 6 as soon as we get ready.

We evaluate approximately 0.6 mSv of effective radioactive doses per year for adults as the impact on the discharge of the low radioactive waste water to the sea if they eat adjacent fish and seaweeds every day. The amount (0.6 mSv of effective radioactive doses per year) is one-forth of annual radioactive dose to which the general public is exposed in nature.

(We already informed.)

Afterwards, we were preparing to discharge the low radioactive waste water to the sea. We intend to start to discharge the low radioactive waste water stored in the Central Radioactive Waste Disposal Facility to the sea at 7:00 pm today on April 4th. In addition, at 9:00 pm today on April 4th, we intend to start to discharge the low level radioactive subsurface water stored in the sub drain pits to the sea.

TEPCO - Tokyo Electric Power Company, press release