Replies

3/13 Morning links and status at Fukushima:

Battle to stabilize earthquake reactors
http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

Venting at Fukushima Daiichi 3
http://www.world-nuclear-news.org/RS_Venting_at_Fukushima_Daiichi_3_1303111.html

Radiation Falls at Japan Atomic Plant; Explosion Still Possible
http://www.businessweek.com/news/2011-03-13/radiation-falls-at-japan-atomic-plant-explosion-still-possible.html

Fukushima Daiichi Unit 1 (1971)
- Automatically shut down during quake; station blackout following tsunami
- Pressure release implemented; steam and hydrogen explosion after pressures hit 840 kPa / 122 psi
- Primary containment believed intact; seawater and boric acid injection continues
- Radiation levels did not rise after explosion, and are currently below regulatory limits

Fukushima Daiichi Unit 2 (1974)
- Automatically shut down during quake; station blackout following tsunami
- Water level lower but steady; Preparations for pressure release

Fukushima Daiichi Unit 3 (1976)
- Automatically shut down during quake; station blackout following tsunami
- High pressure injection system failed; Pressure releases have started
- Injection of fresh water and boron; Seawater injection started
- Potential for steam and hydrogen explosion, similar to Unit 1

Fukushima Daiichi Units 4,5,6 (1978-1979) – all shutdown prior to earthquake for inspection

Fukushima Daini Unit 1 (1982)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release
- Failure of make-up water condensate system

Fukushima Daini Unit 2 (1984)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release

Fukushima Daini Unit 3 (1985)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release

Fukushima Daini Unit 4 (1987)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release

Station Blackout Risk - “It’s considered to be extremely unlikely, but the station blackout has been one of the great concerns for decades,” he told reporters on a conference call. “We are in uncharted territory. We are in the land where probability says we shouldn’t be and we are hoping that all of the barriers to release of radioactivity will not fail.”

Radioactive cesium, a product of atomic fission, was detected near the site yesterday, indicating a meltdown may have begun, said Yuji Kakizaki, a spokesman for the Nuclear and Industrial Safety Agency.

Tokyo Electric began injecting sea water and boric acid to cool its Fukushima Dai-Ichi No. 1 reactor, according to a statement today. The plant’s No. 3 reactor has been vented to release pressurized gas after its cooling system failed, spokesman Akitsuka Kobayashi said earlier.

The “likelihood of success should be fairly high,” Dale Klein, a professor of nuclear engineering at the University of Texas at Austin and former chairman of the U.S. Nuclear Regulatory Commission, said of the seawater flooding. “This should have been part of their overall strategy to keep the core covered and cooled.”