Tokyo Electric Power Co. (TEPCO) has released the following update on the status of on Fukushima Daiichi nuclear power plant.

Unit 1 (Shut down)

* Reactor has been shut down. However, the explosive sound and white smoke were confirmed after the big quake occurred at 3:36 pm Mar 12th. It was assumed to be hydrogen explosion.

*At approximately 2:30 am on March 23rd, seawater was started to be injected to the nuclear reactor through the feed water system.

* At approximately 10:50 am on March 24th, white fog-like steam arising from the roof part of the reactor building was observed.

* At approximately 11:30 am on March 24th, lights in the main control room was restored.

Unit 2 (Shut down)

* Reactor has been shut down and the level of reactor coolant had dropped and the reactor pressure had increased because the Reactor Core Isolation

Cooling System stopped. Measures were taken to lower the pressure within the Reactor Containment Vessel and to inject sea water into the Reactor while carefully confirming safety. The level of reactor coolant and the pressure of the Reactor resumed.

* At approximately 6:00 am on March 15th, an abnormal noise began emanating from nearby Pressure Suppression Chamber and the pressure within this chamber decreased.

* At 6:20 pm on March 21st, white smoke was confirmed arising from the top of the reactor building. As of 7:11 am on March 22nd, smoke decreased to the level where TEPCO can hardly confirm.

Unit 3 (Shut down)

* At around 4:20 pm on March 23rd, TEPCO staff confirmed light black smoke belching from the Unit 3 building. At approximately 11:30 pm on March 23rd and 4:50 am on March 24th, an employee found no signs of smoke.

At approximately 5:35 am on March 24th, sea water injection through Fuel  Pool Cooling and Filtering System was initiated.

On March 24th, it was confirmed that 3 workers from other companies who was in charge of cable laying work in the 1st floor and the underground floor of turbine building were exposed to the radiation dose of more than 170 mSv. 2 out of 3 are being transferred to the hospital as it was confirmed that their leg skin were contaminated.

Unit 4 (outage due to regular inspection)

* At this moment, TEPCO do not consider any reactor coolant leakage inside the reactor containment vessel happened.

Unit 5 (outage due to regular inspection)

* At this moment, TEPCO do not consider any reactor coolant leakage inside the reactor containment vessel happened.

* At 2:30 pm, March 20th, the reactor achieved reactor cold shutdown. At  around 5:24 pm on March 23rd, when it switched the temporary Residual Heat Removal System Seawater Pump, it automatically stopped.

We will repair the pump and maintain the reactor water level and the temperature in the reactor properly. Repair work is being conducted, TEPCO said.

Unit 6 (outage due to regular inspection)

* Reactor has been shut down and the sufficient level of reactor coolant to ensure safety is maintained.

* TEPCO is working on receiving external power supply to Units 5 and 6 and at this moment, it do not consider any reactor coolant leakage inside the reactor containment vessel happened.

Casualties

* At approximately 10 pm on March 22nd, 1 worker who had been working on setting up a temporary power panel in the common pool was injured and transported to Fukushima Daini Nuclear Power Station where the industrial doctor is.

* At approximately 1 am on March 23rd, 1 worker who had been working on transporting a temporary power panel in the common pool was injured and transported to Fukushima Daini Nuclear Power Station where the industrial doctor is.