Status of melted fuel in Fukushima reactors uncertain despite push for early removal

Uncertainty over the location of melted fuel inside the crisis-hit Fukushima No. 1 Nuclear Power Plant continues to cast a shadow over plans to remove the fuel at an early date, as envisaged in a draft version of a revised road map for decommissioning the plants' reactors.
A draft announced by the government and Tokyo Electric Power Co. (TEPCO) on June 10 outlines plans to start removing the melted fuel about 18 months earlier than originally forecast. But the proposed length of time it will take to decommission the reactors has been left unchanged at "30 to 40 years."
Reactor Nos. 1-3 at the plant contained a total of 1,496 rods of nuclear fuel in their cores. Another 3,106 rods of spent fuel are stored in the pools of the No. 1-4 reactors. The melted fuel inside the reactors has been labeled "debris," and is believed to have hardened after mixing with metal and other substances. Each fuel rod weighs about 300 kilograms, and a high level of technical expertise would be required when undertaking a remote control operation to cut up and retrieve clumps of scattered radioactive materials weighing a combined 450 tons or thereabouts.
The bid to remove the melted fuel earlier than planned hinges on whether workers can succeed in filling the reactor cores with water. This method to screen off radiation was used in the Three Mile Island accident that occurred in 1979. However, the cores of reactors at the Fukushima plant have holes, and the task at hand is finding which parts have been damaged and repairing them.
It took about six years before fuel began to be removed in the Three Mile Island accident, but in Fukushima, even if the melted fuel is removed earlier than planned, the work won't start until about 10 years from the onset of the disaster.

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