The cleanup of Japan’s devastated Fukushima Dai-ichi nuclear power plant passed an important milestone on Saturday when the plant’s operator announced it had safely removed the radioactive fuel from the most vulnerable of the four heavily damaged reactor buildings.
Tokyo Electric Power Co (TEPCO) removed the remaining fuel rods from the ruined No. 4 reactor building, putting the rods inside a large white container for transportation to another, undamaged storage pool elsewhere on the plant’s grounds. The company had put a high priority on removing about 1,500 fuel rods from the unit because they sat in a largely unprotected storage pool on an upper floor of the building, which was gutted by a powerful hydrogen explosion during the March 2011 accident.
This led to fears of additional releases of radioactive material if the pool was damaged further, such as by an earthquake. By succeeding in the technically difficult task of extracting the rods, TEPCO eliminated one of the plant’s most worrying vulnerabilities. This is also the first time that fuel has been removed from one of the four wrecked reactor buildings.
It took almost four years to reach this goal, as the cleanup has been plagued by mishaps and a so far unstoppable flow of groundwater that has flooded the basements of the crippled reactor buildings.
The aging Fukushima Dai-ichi plant suffered a triple meltdown when a huge earthquake and tsunami struck on March 11, 2011, knocking out cooling systems.
TEPCO still faces the far more challenging task of removing the ruined fuel cores from the three reactors that melted down in the accident. These reactors were so damaged — and their levels of radioactivity remain so high — that removing their fuel is expected to take decades. Some experts have said it might not be possible at all, and have called instead for encasing those reactors in concrete.
The fuel cores from the three reactors are believed to have melted like wax as the uncooled reactors overheated, forming lumps on the bottom of the reactor vessels. Scientists have said that the hot, molten uranium might have even melted through the containment vessels, possibly reaching the floor of the reactor buildings or even the earth beneath.
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