http://ajw.asahi.com/article/0311disaster/fukushima/AJ201306110092
Removal of nuke fuel debris at Fukushima plant set for 2020
The extraction of melted nuclear fuel rod debris at the Fukushima No. 1 nuclear power plant could begin in 2020, or 18 months earlier than originally anticipated, the central government and Tokyo Electric Power Co. said June 10.
In releasing a draft amendment to the current decommissioning road map, however, the government and TEPCO said they are not expecting the entire decommissioning process to end earlier than they had initially planned, which is 30 to 40 years after the nuclear disaster that was set off by the March 2011 Great East Japan Earthquake.
The latest draft document is the first to have presented the timeline of fuel debris removal separately for the three reactors that went into meltdowns.
It said the extraction process could begin during the first half of fiscal 2020 at the No. 1 and No. 2 reactors, and during the second half of fiscal 2021 at the No. 3 reactor, if circumstances enable workers to follow the least time-consuming methods that involve basic equipment.
But the No. 1, No. 2 and No. 3 reactors will have to wait until the second half of fiscal 2022, the first half of fiscal 2024 and the second half of fiscal 2023, respectively, for the extraction process to begin if the most time-consuming methods have to be followed, the draft said.
The workers have yet to gain a grasp of the locations and condition of the fuel debris. They have yet to develop extraction equipment and determine removal methods.
The government and TEPCO are expected to meet by the end of June to revise their decommissioning road map on the basis of the latest draft amendment.
http://mainichi.jp/english/english/newsselect/news/20130611p2a00m0na010000c.html
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.
The government and TEPCO plan to conduct a detailed investigation next fiscal year on the technology needed to decommission the Fukushima plant's crippled reactors, then make a final decision on whether it is possible to start the removal work earlier.
In a news conference on June 10, a representative of the Ministry of Economy, Trade and Industry's Agency for Natural Resources and Energy said that bringing forward the plans would be dependent on developing technology, and suggested that the plans might even end up being delayed.
Minister of Economy, Trade and Industry Toshimitsu Motegi played a leading role in revising the roadmap. This has raised suggestions that announcing plans to start removing the fuel earlier than originally forecast is a way for the government administration to underscore its achievements since taking over the reins of government last year, ahead of the upcoming House of Councillors election.
University of Tokyo professor Satoru Tanaka, who is familiar with the decommissioning of nuclear plants, commented, "There is merit in bringing the plans forward to speed up residents return (to areas contaminated by the nuclear accident). But there remains a lot of unchartered technology, and the government needs to support research and development in the future."
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