Japan still aims to start removing fuel debris from stricken reactors in 2021 — The Japan Times

To add a little context to the issue of removing molten fuel from Units 1, 2 and 3 of Fukushima Daiichi, keep in mind while reading this article that no one knows exactly where the melted fuel is, and, therefore, making any plans to remove the fuel is based on a leap of faith that someone will first figure out where the fuel is and then figure out how to safely remove it.

” Japan still aims to start removing nuclear fuel debris at the three damaged reactors at Tokyo Electric Power Co.’s Fukushima No. 1 power plant in 2021, it was learned Thursday.

The schedule remained intact in a draft update to the government’s roadmap to the decommissioning of reactors 1, 2 and 3, all of which experienced fuel meltdowns during the nuclear disaster from March 2011. The draft was submitted to a meeting of a government task force on the matter.

But it looks inevitable that the government will review the schedule. The exact location of the molten nuclear fuel in the reactors is still unknown and radiation levels in and around the reactors are very high.

In autumn last year, the government and Tepco discussed a delay of about five years in the start of work to remove the fuel debris from reactor 1.

But the draft said Japan will choose the method to remove the debris by the end of September 2018 and start taking out the molten fuel by the end of 2021. It is still unclear which reactor Japan will choose for the first removal work.

Meanwhile, the government is reviewing the schedule for removing spent fuel at storage pools at the three reactors.

Removal work has been slated to begin for reactor 3 by the end of this September. But the work will likely be delayed because radiation levels remain high and operations to remove rubble from the damaged building have not progressed as planned. ”



Three methods proposed for removing melted fuel from Fukushima No. 1 reactors — The Japan Times; The Yomiuri Shimbun

” FUKUSHIMA – The Nuclear Damage Compensation and Decommissioning Facilitation Corp. on Thursday proposed three methods for retrieving highly radioactive nuclear fuel debris in three crippled reactors at Tokyo Electric Power Co.’s disaster-stricken Fukushima No. 1 nuclear power plant.

The proposals, presented at a meeting of officials from Tepco, the central government and municipalities in Fukushima Prefecture, will be reflected in a decommissioning road map that the government and Tepco are set to release around May.

The three reactors underwent core meltdowns in March 2011, leaving melted nuclear fuel debris on the floor of their containment vessels. The decommissioning aid body hopes to establish concrete procedures by the first half of fiscal 2018.

One of the three proposed methods removes the debris in a submerged condition, with a containment vessel filled with water to shield against radiation and prevent the spread of radioactive materials during the retrieval process.

An alternative dry method carries out the retrieval in a partially submerged condition, with water used only when the debris is cut loose from the vessel floor. The debris would be removed from either the top, under one plan, or the side of the vessel, under another.

The submersion method requires the reactor damage to be accurately identified and repaired before water is poured in. The dry method, on the other hand, requires continuous cooling of the retrieved debris and measures to prevent radioactive materials from scattering.

Radiation levels at the three reactors are so high that workers have been unable to approach their containment vessels or identify the location of the debris. All the three methods call for an assessment beforehand of radiation contamination as well as decontamination procedures.

Tepco plans to begin inspections of reactor 1 Friday using robots mounted with cameras and radiation-measuring equipment. ”


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Read a related article by The Yomiuri Shimbun