[ALERT] Meltdown confirmed

What the New York Times calls "at least a partial meltdown" has occurred at the Fukushima I nuclear power plant's reactor 3. The fact that plutonium has been found in the soil outside this reactor is conclusive evidence that the steel core containment vessel has been breached. The cause of this compromise of the containment vessel and building is the consequence of excessive heat generated by the ongoing nuclear reactions inside the core -- in short, a "meltdown" has occurred.

This is a catastrophe of this highest order -- it really doesn't get much worse than this in the nuclear industry. And the area will be unaccessible and uninhabitable for many decades.

More reporting from ABC.

[ALERT] Nuclear Event Scale goes to 6 out of 7

• Fears of a catastrophe at the Fukushima nuclear power plant in Japan escalated following a third explosion and a fire in another reactor that caused radiation to rise to harmful levels.
France's ASN nuclear safety authority says the nuclear accident at the Fukushima Daiichi plant could now be classed as level six out of the International Nuclear Event Scale of one to seven.

Guardian link

[ALERT] US expert: Breach possible at Japan nuclear plant

Associated Press

US expert: Breach possible at Japan nuclear plant

Associated Press, 03.15.11, 11:17 AM EDT

WASHINGTON -- A U.S. nuclear industry official says there is evidence that the primary containment structure at one of the stricken Japanese reactors has been breached, raising the risk of further release of radioactive material.

Anthony Pietrangelo of the Nuclear Energy Institute said Tuesday that falling pressure inside the suppression pool at the No. 2 reactor at Fukushima Dai-ichi and reports of rising radiation levels there raise the possibility that the reactor's containment has been breached. He said the breach of the primary containment structure could lead to the release of more radioactive materials.

Pietrangelo, chief nuclear officer of the institute, also praised Japanese authorities, saying that they were doing a "heroic" job of dealing with the damage to several nuclear plants in the wake of last week's earthquake and tsunami.

Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

[ALERT] Core meltdown at Fukushima Dai'ichi highly likely

There is some good reporting on the state of the containment efforts at the out-of-control nuclear fission reaction housed in the Fukushima I Nuclear Power Plant. The New York Times has a lengthy article. There is an excellent description, of a moderately technical nature, on the Beyond Nuclear website. And a lot more that you can find among the noise.

There is a little gold-mine of an interview of a nuclear engineer (done by his daughter). [Video/audio/transcript available.]

The short version is this: a skeleton staff of personnel of about 60 people at the Fukushima I Nuclear Power Plant stands a very low probability of averting a meltdown. From the Times article:

“We are on the brink,” said Hiroaki Koide, a senior reactor engineering specialist at the Research Reactor Institute of Kyoto University. “We are now facing the worst-case scenario. We can assume that the containment vessel at Reactor No. 2 is already breached. If there is heavy melting inside the reactor, large amounts of radiation will most definitely be released.”