Nuclear fuel has melted through base of Fukushima plant

The nuclear fuel in three of the reactors at the Fukushima Dai-Ichi nuclear plant has melted through the base of the pressure vessels and is pooling in the outer containment vessels, according to a report by the Japanese government.

The findings of the report, which has been given to the International Atomic Energy Agency, were revealed by the Yomiuri newspaper, which described a “melt-through” as being “far worse than a core meltdown” and “the worst possibility in a nuclear accident.”

A spokesman for Tokyo Electric Power Co. said the company is presently revising the road-map for bringing the plant under control, including the time required to achieve cold shutdown of the reactors.

In a best-case scenario, the company says it will be able to achieve that by October, although that may have to be revised in light of the report.

Water that was pumped into the pressure vessels to cool the fuel rods, becoming highly radioactive in the process, has been confirmed to have leaked out of the containment vessels and outside the buildings that house the reactors.

Tepco said it is trying to contain the contaminated water and prevent it from leaking into the sea, but elevated levels of radiation have been confirmed in the ocean off the plant.

The radiation will also have contaminated the soil and plant and animal life around the facility, making the task of cleaning up more difficult and expensive, as well as taking longer.

The experts have also yet to come up with a plan for decommissioning the ruined plant. Studies have estimated that the cost of the accident at Fukushima may rise as high as $250 billion over the next 10 years.

via Nuclear fuel has melted through base of Fukushima plant – Telegraph.