Friday, March 11, 2011

The Japan Earthquake and the Fukushima Daiichi Nuclear Plant

From World Nuclear News:

Later, Tokyo Electric Power Company (Tepco) reported that emergency diesel generators started as expected at the Fukushima Daiichi nuclear power plant, but then stopped after one hour, leaving units 1, 2 and 3 with no power for important cooling functions. This led the company to notify the government of an 'emergency' situation, which allows local authorities to take additional precautionary measures. An evacuation has been ordered of over 1000 people living within three kilometres, while engineers worked to restore power.

Almost nine hours later, an announcement from the Ministry of Economy, Trade and Industry said that three of four mobile power supplies had arrived at Fukushima Daiichi and cables were being set up to supply emergency power. Other power modules were in transit by air.

However, pressure inside the containment of Unit 1 at Fukushima Daichi had been steadily increasing over the time that emergency core cooling systems have not been active. Tepco reported at 2am that pressure had increased beyond reference levels but was within engineered limits.

The company then announced a decision to reduce the pressure within containment "for those units that cannot confirm certain level of water injection" by the safety systems. "We will endeavor to restore the units and continue monitoring the environment of the site periphery."

This has to be the origin of Clinton's ridiculous statement about the Air Force flying water into Japan; I could understand the Japanese wanting to borrow a mobile power cell or two, but the water thing is idiotic and of course is credulously being repeated in the media.

The anti-nuke crowd is distorting this just as quickly as they can get their hands unwrung. As far as I can tell, Fukushima Daiichi had a double failure, went to battery backup, and is taking steps to bring in alternate power, which is of course what the battery backup is for in the first place. This is clearly a serious accident, but everything seems to be working as designed, as far as I can tell.

UPDATE 9:48 CST: Guess I haven't called this one very well so far:

Meanwhile at adjacent Fukushima Daini, where four reactors have been shut down safely since the earthquake hit, Tepco has notified government of another emergency status.

Unit 1's reactor core isolation cooling system had been operating normally, and this was later supplemented by a separate make-up water condensate system. However, the latter was lost at 5.32am local time when its suppression chamber reached 100ÂșC. This led Tepco to notify government of another technical emergency situation.

Tepco has announced it will soon begin controlled releases to ease pressure in the containments of units 1, 2 3 and 4 at Fukushima Daini.

A three kilometre evacuation is in progress, with residents in a zone out to ten kilometres given notice of potential expansion.

In addition, the Daiichi site is leaking radiation from something other than its controlled release. No way to tell if this is resulting from core damage or some minor problem.

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