New Submersion Method Being Considered for Fukushima Debris Cleanup
AmiMoJo writes: The operator of the Fukushima No. 1 nuclear power plant, which suffered core meltdowns in 2011, is considering a new submersion method for removing radioactive fuel debris that would wholly encase a reactor building in a water-filled, tank-like structure, a source close to the company said earlier this month. Conceptual breakthroughs with the method, whose advantages include using water's ability to interrupt radiation and thereby provide a safer working environment, have made it a promising candidate for the cleanup of the defunct nuclear plant, according to the source close to Tokyo Electric Power Company Holdings (Tepco). But with no proven track record in the nuclear field, investigations are ongoing into future technological issues and costs, among other contingencies. The source said it could "require advanced technology to stop water leaking out and become a huge construction project." Were it to go ahead, the process from building to actual debris removal would be lengthy and would likely affect total decommissioning costs, currently pegged at about $57.45 billion. In the aftermath of the March 2011 Great East Japan Earthquake and tsunami, nuclear fuel cooling processes failed at the Fukushima plant's reactors 1 through 3, causing the fuel to melt and re-solidify into radioactive debris mixed with concrete, metal and other materials present in the reactors. Debris removal is the operator's most challenging issue in the Fukushima plant cleanup. Some 880 tons of the radioactive waste material is estimated to have been created by the nuclear meltdown across the three reactors. The new submersion method, which is currently expected to be applied to the No. 3 reactor, would involve building a strong, pressure-resistant structure, much like a ship's hull or a plane's body, completely encapsulating the reactor, including underground. The structure could then be filled with water, and removal work would take place from the top.
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