Remember when I compared the Fukushima situation to that old joke about "the cat's on the roof"? Yes, I remember all the reasonable, rational, technical folks explaining to me how irresponsible and crazy I was for saying this was what happened.
And yet, it did:
The Tokyo Electric Power Corp. says Unit 1 at the Fukushima Daiichi nuclear power plant did, in fact, meltdown during the 2011 accident.
TEPCO released results from a three-day study in February of the Unit 1 reactor building jointly with the International Research Institute for Nuclear Decommissioning. The two companies collected data until March 10. The project used cosmic rays to inspect the interior of the building. By analyzing the flow of muons, which are subatomic particles generated when cosmic rays collide with the atmosphere, TEPCO was able to generate X-ray like images of the interior of the reactor. Muons can pass through concrete and iron, but they are blocked and change direction when they hit high-density substances such as plutonium and uranium, creating a “shadow.”
TEPCO said the fuel had melted because there were no shadows around the reactor’s core, and the fuel had likely melted and fallen to the bottom of the building into a containment vessel. The operator also said there was no accumulation of water in the core of the reactor pressure vessel.
TEPCO said the results confirmed previous assumptions of a meltdown. The utility plans to continue measurement until it gains enough data to conduct a statistical analysis, and said the data gained will help it work out a plan to remove the debris, most likely by robots due to the high amounts of radiation in the reactor.
First of all, it's not an "accident." TEPCO cut corners to save money, and this is the predictable result.
And who are they kidding? The containment vessel melted, too. They didn't scan the containment area because they don't want us to know that. That fuel is out there. And we can probably assume the same about Unit 2.
With a situation like Fukushima, engineer types believe in their fail-safe systems -- the system does not fail! But that's because technical people are not as good at assessing human factors like corruption, company leadership and dangerous cost-cutting until they see it with their own eyes.