Gov’t Official: It is a fact that nuclear fuel melted a hole through Reactor No. 1

Tokyo Electric Power Company is being forced to review its strategy for stabilizing the Fukushima Daiichi nuclear plant after announcing that one of its reactors is in a state of “meltdown.” <...>

Economy, Trade and Industry Minister Banri Kaieda said it is a fact that the water injected into the No.1 reactor leaked away because of a hole or holes created by the meltdown.

He said this is the main reason why TEPCO’s plan needs to be reviewed.
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Most likely ‘solution’ to fuel melting through reactor is a concrete wall around Unit No. 1 — “Could now take years” to encapsulate because of high radiation

U.S. nuclear experts said that the company may have to build a concrete wall around the unit because of the breach, and that this could now take years.

“If it is assumed the fuel did melt through the reactor, then the most likely solution is to encapsulate the entire unit. This may include constructing a concrete wall around the unit and building a protective cover over it,” W. Gene Corley, senior vice president of CTL Group in Skokie, Illinois, said on Thursday.

“Because of the high radiation that would be present if this has happened, the construction will take many months and may stretch into years,” Corley said.

http://www.reuters.com/article/2011/05/12/japan-nuclear-reactor-idUSL3E7GC2JQ20110512
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NYT: TEPCO had hoped that Reactor No. 1 was the “easiest to bring under control” as No. 2 and 3 are believed to be breached and leaking...

http://www.nytimes.com/2011/05/13/world/asia/13japan.html?_r=1&partner=rss&emc=rss
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The flow of bad news (and radiation) out of Fukushima’s reactors has diminished to a trickle over the past several weeks, as rescue work has proceeded. Not today. TEPCO’s admitted for the first time that Fukushima experienced a grave meltdown. <...>

TEPCO workers and the Japanese government have desperately struggled to keep the nuclear fuel rods inside the reactors cool—if they don’t, the scorching material will melt into a pool of radioactive lava, further damaging the facility. That’s the scenario everyone’s been aiming to avoid—and that’s the scenario we now know had actually occurred all along. Underneath all that dumped seawater has been lying a blob of melted fuel. And it could be melting its way out.

This admittance goes against every assurance TEPCO has handed the world in the midst of Japan’s nuclear crisis <...>

http://enenews.com/its-official-fukushima-was-hit-with-a-full-blown-nuclear-meltdown
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I am having a hard time keeping all the reactors straight. Is there only one meltdown or three?

:sarcasm:

There isn't a precise technical definition of "meltdown",
so it can be used with different connotations.
"Core damage" is the closest technical term, but isn't very descriptive.
Three Mile Island is called a "partial meltdown" because only some of the fuel melted.

It is hard to keep it all straight. I suspect it is so highly technical that some people can't even process it all.

Thanks so much for taking the time to explain. Yikes.