Fukushima Dai-ichi nuclear plant: Status on March 25th

It is 2 weeks today since the quake and Tsunami struck. The toll of dead and missing exceeds 27,000.

Progress continues steadily but painfully slowly at the Fukushima Dai-ichi nuclear plant. The radiation levels are fluctuating but pose no health hazard to the general public. Containment vessel at Reactor #3 is damaged and may be causing radiation spikes.

From JAIF

  • The work to restore external AC power for units-1, 2, 3 and 4 is in progress. External AC power to the main control room at unit-2 will be available today. According to TEPCO, the reactor surface temperature at unit-1 increased to  approx. 400 ° C once (design assumption maximum 302 ° C).  Now it has dropped to 204.5 ° C (as of 06:00 on March 25).
  • Meanwhile,  in the turbine building at unit-3, drainage work is also in progress. (10:45, March 25)
  • On March 24, 2 workers, who were working to lay electrical cables in turbine building at unit-3, were sent to the hospital. TEPCO suspected that the nuclear fuel in the reactor or spent nuclear fuel at the pool was damaged and water contaminated with high radioactivity was leaked  to the workspace. Further investigation is now carrying on. These 2 workers were not wearing boots. Another worker wearing boots is safe. (07:15, March 25).
  • As for the coolant of reactors at Fukushima Daiichi, TEPCO would like to switch from seawater to fresh water as fast as possible. The first switch will be carried out at unit 3. (04:30, March 25)
  • Ministry of Defense announced that the Self-Defense Force helicopter measured the surface temperatures of Fukushima Daiichi units-1, 2, 3 and 4 from the air by using infrared rays and  found that the temperature of each units is below 20 ° C. Unit-1:17 ° C; Unit-2: 13°C; Unit-3: 11 °C; Unit-4: 17 °C (as of the morning on March 24). Especially, the surface temperature of the spent fuel pool at unit-3 dropped significantly to 31 °C, compared to 56°C on the previous day. (21:15, March 24)

From IAEA:

Unit 1: Workers have advanced the restoration of off-site electricity and lighting in the Unit’s main control room was recovered as of 24 March, 11:30 UTC. They are now checking the availability of the cooling system. While the pressure in the reactor vessel remains high, Japanese authorities are reporting that it has stabilized.

Unit 2: Engineers are working for the recovery of lighting in the main control room, and the instrumentation and cooling systems.

Unit 3: Around 120 tonnes of seawater was injected in the spent fuel pool via the cooling and purification line. The operation was carried out between 23 March, 20:35 UTC and 24 March, 07:05 UTC. Work was under way for the recovery of the instruments and cooling systems. However, it had to be suspended because three workers were exposed to elevated levels of radiation on 24 March.

Unit 4: The spent fuel pool was sprayed with around 150 tonnes of water using concrete pump truck. The operation was carried out between 24 March, 05:36 UTC and 06:30 UTC of the same day.

Units 5 and 6: Repair of the temporary pump for Residual Heat Removal (RHR) was completed as of 24 March, 07:14 UTC, and cooling started again 21 minutes later.

At the Common Spent Fuel, the power supply was restored as of 24 March, 06:37 UTC and cooling started again 28 minutes later. Work is now under way for the recovery of the lighting and instrumentation systems. As of 24 March, 09:40 UTC, the water temperature of the pool was around 73 °C.

As of 24 March, 10:30 UTC workers continue to inject seawater into the reactor pressure vessels of Units 1, 2 and 3 and are preparing to inject pure water.

 

About these ads

Tags: , ,


Follow

Get every new post delivered to your Inbox.

Join 492 other followers

%d bloggers like this: