28 Juin 2013
Work to remove melted fuel from the three crippled reactors at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear plant could start in 2020, the government and Tepco optimistically said Thursday, based on a revised, albeit vague, plan to decommission the stricken complex, a process expected to take decades.
The original melted-fuel extraction was expected to start in 2021, but the government, without elaborating, believes an improvement in work efficiency can move the date forward.
Tepco, however, said an exact start date currently is hard to forecast because the position and state of the fuel in reactors 1, 2 and 3, which suffered core meltdowns, remains unclear and all the utility can do at present is try, with makeshift equipment, to keep water circulating through the damaged containment vessels to prevent further massive radioactive fallout.
The moved-up fuel extraction timetable is the first major revision of the road map outlining the 40-year-long process of scrapping reactors 1 to 4 at the six-reactor complex. The original schedule was released in December 2011, after Fukushima No. 1, ravaged by the March 11, 2011, Great East Japan Earthquake and monster tsunami was deemed in a stable state of “cold shutdown.”
The plant is technically currently in the first phase of decommissioning, with Tepco hoping to start in November extracting the fuel inside the spent-fuel pool located outside but atop reactor 4, whose building was ripped apart in a hydrogen explosion.
Reactor 4 was offline for maintenance, and thus empty of fuel, when the catastrophe struck, so only its spent-fuel pool needs to be unloaded, although due to the high levels of radiation in and around the building, this will be a delicate operation requiring high levels of technology. Finding a safe location to store the extracted fuel will also pose hurdles.
The second phase of the decommissioning, based on the revised plan, will entail the removal of the melted fuel from crippled reactors 1 and 2 starting in fiscal 2020 if possible, followed by work to start removing the melted fuel inside reactor 3 in the latter half of fiscal 2021 at the earliest. Reactor 3′s fuel is the highly lethal mixed uranium-plutonium oxide (MOX) fuel.
The extractions may be delayed if proper equipment isn’t available to deal with the three stricken reactors, whose levels of damage and radiation differ.
The buildings housing reactors 1, 3 and 4 were damaged by hydrogen explosions, while the radiation level inside the reactor 2 building is very high.
Another scenario points to starting the fuel removal of reactor 1 in fiscal 2022, that of reactor 2 in fiscal 2024 and reactor 3′s fuel in fiscal 2023.
The original road map only suggested the fuel removal may start in December 2021, without specifying which reactor would be worked on first.
The fuel inside reactors 1, 2 and 3 is believed to have melted through the pressure vessels and accumulated somewhere in the outer primary containers, making the task of extraction more challenging than in the case of the 1979 Three Mile Island accident in Pennsylvania.
June 27, 2013
Roadmap revised for scrapping Fukushima reactors
Japan's government and the operator of the Fukushima Daiichi nuclear power plant have officially endorsed a renewed roadmap for scrapping the crippled reactors.
Officials of the government and Tokyo Electric Power Company approved the revision in a joint panel meeting on Thursday.
The revision is meant to accelerate work to dismantle the plant's 4 reactors, which were disabled in the March 2011 earthquake and tsunami.
But officials warn the work could fall behind schedule because engineers have yet to determine the exact state of melted fuel inside the reactors.
The revised roadmap has set different timelines for removing fuel from the No. 1, 2 and 3 reactors. No.4 was offline at the time of the accident.
Removal could start in the first half of 2020 at the earliest at the No. 1 and No. 2 reactors. That's one and a half years sooner than the previous plan.
Officials say decommissioning work, including tearing down reactor buildings, could take as long as 40 years.
The panel also decided to form a new organization to hear from people in the region about how to proceed with the work. Industry minister Toshimitsu Motegi said communications with local people must be strengthened.
Motegi told officials to steadily proceed first with removal of fuel rods from the pool at the No.4 reactor, and make proper decisions for each of the 3 others on when to start the work.