Tokyo Electric Power Co. on Saturday laid out a rough timeline for controlling damaged reactors and spent fuel tanks at its Fukushima Daiichi nuclear plant.While the measures the company plans to take – flooding containment vessels, isolating contaminants, injecting nitrogen into cores to prevent hydrogen explosions and covering reactor buildings to prevent radiation releases – are not new ideas, the announcement represents the first long-term plan the company has laid out for the plant since it lost power during a March 11 earthquake and tsunami.TEPCO said that after 3 months it expects radiation levels to decline at the plant, followed by cold shutdown in reactors 1 though 3 within six months. Also in that timeframe the company plans to cover units 1, 3 and 4 using a temporary “scaffolding” to minimize the escape of radioactive elements from damaged reactor buildings.In the near-term, TEPCO will strengthen the walls and base of the spent fuel tank in unit 4. Unit 2 will continue to be drained of irradiated water believed to contribute to some of the highest dose readings at the plant. Eventually, the company will flood the containment vessels of units 1 through 3, with unit 2 requiring additional work to seal its containment vessel beforehand.TEPCO began injecting nitrogen into unit 1 April 6 and plans to do the same for units 2 and 3 by the end of the month, according to a Bloomberg report. Other near-term actions include the recent placement of bags filled with sand and contaminant-absorbing zeolite in water adjacent to the plant to counteract elevated levels of radioactive elements found in seawater samples.
- Download Part One of TEPCO's Plan for Fukushima Daiichi
- Download Part Two of TEPCO's Plan for Fukushima Daiichi
- Download an illustration of countermeasures proposed at Fukushima Daiichi.
(Photo: A robot works inside the unit 3 reactor building at Fukushima Daiichi. Source: TEPCO)
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