Fukushima Daiichi NPS Prompt Report 2013

At around 10:16 AM today (July 25), the residual heat removal B system, which was cooling the reactor, has stopped after the 6.9 kV metal-clad (power panel) C at Unit 6 was suspended during the logic verifying test (automatic starting test) of Unit 6 emergency diesel generator at Fukushima Daiichi Nuclear Power Station.

Currently, we are proceeding with the preparation to restart the reactor cooling by the residual heat removal B system, and it is expected to be restored within about an hour.

The other statuses are as follows.

- Air conditioning of the Reactor Building has stopped, and the emergency gas treatment system^* has started.
(The negative pressure of the Reactor Building is being maintained.)
- Cooling system of the spent fuel pool is operating continuously.
- Water temperature of the reactor as of 10:43 AM is 27.1℃. The increase rate of reactor water temperature is estimated to be approx. 1℃ per hour.

* Emergency gas treatment system
A device, which closes regular ventilation system automatically and maintains the negative pressure inside the Reactor Building as well as removing radioactive iodine and particle radioactive material in the building utilizing charcoal filter, high performance particle filter, etc. to reduce the emission of radioactive material to the environment in case radioactive leakage accident occurs in the Reactor Building.

We are now confirming the status and preparing toward restoration, and will announce the status as soon as we know it.