Fukushima Daiichi NPS Prompt Report 2014

Removal of temporary cover with full consideration of the surrounding environment first step of cleanup of reactor building

FUKUSHIMA, Japan, August 1, 2014. A major step is being taken towards the cleanup of one of the three reactors at the Fukushima Daiichi plant that were destroyed in the tsunami following the Great Japan Earthquake of 2011.

Since October of that year, the Unit 1 building has been shrouded by a temporary cover that was erected to protect the building from the elements and minimize the amount of radioactivity that might escape.

Now, with the remaining nuclear debris stabilized, emissions are roughly one one-hundredth of what they were when the cover was constructed. It can now be safely removed so that TEPCO can begin removing debris from the operating floor, an essential step toward eventual decontamination and decommissioning.

Removal of the cover is an essential step toward erection of the large overhead crane that will be used to remove the debris, similar to the one currently being used to safely remove fuel from Unit 4. The temporary will be replaced by a structure capable of supporting the crane's weight.

"This is another major milestone in the journey towards safe decommissioning," said Naohiro Masuda, TEPCO's Chief Decommissioning Officer. "It is the result of many months of preparation and the employment of innovative technology and multiple efforts to ensure safety for workers and for the environment. I'm determined to ingather the lessons learnt from the debris removal work of Units 3, to further protect the surrounding environment and our workers from radiation exposure."

Radiation Reduction and Worker Safety

It is estimated that radiation at the site boundary attributable to Unit 1 after the cover is removed will be only between 0.002 and 0.004 milliSieverts per year, well below the limit set by 1 millSieverts per year within two years.

To protect workers, and to prevent the spread of radiation during removal of the cover, a variety of steps are being taken:

 • Small debris and dust will be sucked up and cleared before starting the cover dismantling.
 • Anti-scattering agent will be used to fix radioactive substances and prevent their escape into the atmosphere or groundwater
 • Rubble will be sprinkled with water to hold down dust, and the water will be vacuumed up, treated, and stored.
 • Radiation levels will be constantly monitored at more than 20 points on the premises
 • To limit worker exposure, machinery will be operated by remote control

While removal of the cover will temporarily expose the interior of the building to the elements, any rainwater will be kept within the building and treated and stored along with other water on the site. The debris from the cover removal will be stored on-site.

After removal of the cover and the cleanup of the rubble left from the March 2011 accident, efforts will begin to remove nuclear fuel from FY 2017.

Illustrated materials may be obtained at http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2014/images/handouts_140801_01-e.pdf

To learn more, please go to http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2014/images/handouts_140717_04-e.pdf

About TEPCO

Tokyo Electric Power Company, Inc. (TEPCO) is Japan's largest power company, supplying energy to the greater Kanto area, including Japan's two most populous cities, Tokyo and Yokohama. Its 35,000 employees are committed to providing safe, reliable power to its 28.8 million customers, diversifying energy resources to ensure sustainability, and contributing to economic growth while fully meeting its responsibilities after the Fukushima Daiichi accident.