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TEPCO Opens Up Space in Common Pool at Fukushima Daiichi to Receive Spent Fuel from Unit 3

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“X-6 penetration” at Unit 5
4 June, 2018
On May 31, the Tokyo Electric Power Co. (TEPCO) released a progress report on the decommissioning at the Fukushima Daiichi Nuclear Power Plants.
Four days earlier, on May 27, the power company began transferring some of the spent fuel currently stored in a common pool to a temporary facility at the site, for storage in dry casks, to create enough space in the pool to store spent fuel taken from the Unit 3 spent fuel pool when that is eventually removed.
At the temporary storage facility, TEPCO will pack the spent fuel in dry casks providing shielding and heat removal (with natural air circulation outside the casks) and store it under stable conditions.
By August, 483 spent fuel assemblies from the common pool will have been transferred to the facility using seven transport and storage casks, in anticipation of the arrival of 566 fuel assemblies (including unused 52 assemblies) from Unit 3.
On May 11, a problem was found at Unit 3—where a fuel handling machine has been in trial operation since March—inside a control panel for a crane used for moving fuel transportation containers to the ground. TEPCO nevertheless aims to begin removing fuel from the spent fuel pool around mid-FY18, as initially planned.
TEPCO will determine a method for removing fuel debris from the first unit by FY19 (April 2019 to March 2020), and the status of that effort was also included in the status report on May 31. The approach is to proceed after heightened understanding is made of internal conditions, the nature of the debris, and the effects when removed.
As that has not yet been fully completed, though, the effort will proceed gradually and incrementally, as follows: first investigating the interiors of the primary containment vessels (PCVs) through sampling, then carrying out small-scale removal of debris, followed by large-scale removal.
As for small-scale fuel removal, one promising method seems to be using a “X-6 penetration” rail to access the interiors of the PCVs (found in all the units) from the side, in order to exchange the control rod drive mechanism (CRDM). That method is already being used for inserting investigation devices into PCVs.
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June 7, 2018 Posted by | Fukushima 2018 | , , | Leave a comment

Construction of a New Cover Building Installation for Spent Fuel Removal at Unit 3

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This installation will enable robotic removal of spent fuel removal to begin at Fukushima Daiichi Unit 3. Plans to remove this fuel have been complicated by high radiation levels.

To install the cover building’s cylindrical portion workers will have to enter the area to manually bolt the cover to the deck structure.

Installation of the “stopper” by a crane near the spent fuel pool began on January 17 as the first step to construct a new roof for the Unit 3 spent fuel removal. Over the pool some additional structural equipment has also been installed.

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Tepco will proceed with the roof construction toward eventual fuel removal with safety as a top priority.

Source : http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2017/images/handouts_170117_01-e.pdf

January 18, 2017 Posted by | Fukushima 2017 | , , | Leave a comment

Debris Removal at Reactor # 3 Delayed, but Arrival of the First Elements of the New Building for its Spent Fuel Removal

Transportation of the supporting part of a new roof for the Unit 3 fuel removal at Fukushima Daiichi Nuclear Power Station


The clearing of debris from reactor # 3 is delayed, delaying the construction of the new building to remove spent fuel from the pool. The debris removal was to be done in order to build a new workshop to remove the fuels from the pool.
The removal of the spent fuel should have started in January 2018. In the beginning, TEPCo was to start in 2015. We do not know their new schedule yet.


On the other hand, TEPCO communicated on the arrival of the first elements of the new building, with photos and video.

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The dose rates on the site are here. There is up to 2.6 mSv / h in the vicinity of reactor No.3.

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Links from TEPCO:
Photos of the new building
http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2016/images/handouts_161220_01-e.pdf
Video
http://photo.tepco.co.jp/en/date/2016/201612-e/161220-01e.html
Dose rates in Reactor 3 vicinity
http://www.tepco.co.jp/en/nu/fukushima-np/f1/surveymap/images/f1-sv-20161219-e.pdf

January 3, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Fuel removal at Fukushima reactor again faces delay

dec-23-2016

Steel frames are transported at the Fukushima No. 1 nuclear power plant on Dec. 20 to prepare for work to retrieve spent nuclear fuel from the storage pool of the damaged No. 3 reactor building.

Work to retrieve spent nuclear fuel in the No. 3 reactor building storage pool of the crippled Fukushima No. 1 nuclear power plant will again be postponed due to a delay in clearing radioactive debris at the site.

TEPCO planned to begin removing 566 spent nuclear fuel assemblies in the storage pool in January 2018. However, the government and the plant operator, Tokyo Electric Power Co., decided on the postponement, sources said on Dec. 22. They will decide on a new timetable in a few weeks.

The work was initially scheduled for fiscal 2015, but had been pushed back because of high radiation readings in and around the No. 3 reactor building. The building was heavily damaged by a hydrogen explosion in the days following the disaster, triggered by the 2011 Great East Japan Earthquake and tsunami.

TEPCO had attempted to lower radiation levels by clearing the radioactive debris remaining at the site.

But the clearing work took longer than expected due to contamination being more widespread than previously thought, forcing TEPCO and the government to again put off the retrieval.

Radiation levels have now dropped as almost all of wreckage at the site has been cleared, TEPCO said. The government and TEPCO have said fuel retrieval at the No. 1 and No. 2 reactor buildings will start in fiscal 2020 or later.

http://www.asahi.com/ajw/articles/AJ201612230043.html

December 23, 2016 Posted by | Fukushima 2016 | , , , | Leave a comment