Decontamination is one of the measures for radiation protection*to remove radioactive materials from the inhabitation areas in order to promptly decrease impacts on human health and the environment.
*The national government aims at a long-term goal to reduce additional annual dose to 1 mSv or less by comprehensive measures for radiation risk management including not only decontamination, but also monitoring survey, food safety administration, risk communication, etc.

Progress of Decontamination

Progress in the Special Decontamination Area (as of the end of Jan 2017)

Municipalities in which evacuation orders were lifted

Municipality Evacuation order was lifted on
Tamura city April 1, 2014
Kawauchi village
(former “Areas to which evacuation orders are ready to be lifted”)
(former “Areas in which residents are not permitted to live”)

October 1, 2014

June 14, 2016

Naraha town September 5, 2015
Katsurao village June 12, 2016
Minamisoma city July 12, 2016

Municipalities in which whole area decontamination were completed

Municipality Time of Completion*
Tamura city June 2013
Naraha town March 2014
Kawauchi village March 2014
Okuma town March 2014
Katsurao village December 2015
Kawamata town December 2015
Futaba town March 2016
Iitate village December 2016
Tomioka town January 2017
* Time of decontamination completion means the time which decontamination is completed in the area with residents’ consents

Status of the whole area decontamination

* Aimed to complete all the decontamination by the end of March 2017

Municipality Residential area Farmland Forest Road
Achieved number
[target number]
Achieved area
[target area]
Achieved area
[target area]
Achieved area
[target area]
94%(84%) 1,600ha
92%(81%) 1,200ha
94%(71%) 240ha
Tomioka 100% 6,000 100% 670ha 100% 460ha 100%(99.9%) 170ha
Namie 95%(94%) 5,300
95%(91%) 1,400ha
99.8%(99%) 380ha
91%(87%) 190ha
Iitate 100% 2,000 100% 1,900ha 100% 1,500ha 100% 310ha
Tamura 100% 140 100% 140ha 100% 190ha 100% 29ha
Naraha 2,600 830ha 470ha 170ha
Kawauchi 160 130ha 200ha 38ha
Okuma 180 170ha 160ha 31ha
Katsurao 460 470ha 630ha 110ha
Kawamata 360 600ha 510ha 71ha
Futaba 97 100ha 6.2ha 8.4ha
Total number of
  22,000   8,000ha   5,700ha   1,400ha
  • Implementation ratio: Decontamination-completed area / Target decontamination area (“Areas where it is anticipated that residents will face difficulties in returning for a long time” are basically not included).
  • Numbers in () are the numbers in a previous month.
  • { } in Minamisoma indicates the implementation rate for all the areas which were ready for decontamination by the end of March 2015.

For more detail and recent information, please check the progress sheet;

Progress on Off-site Cleanup and Interim Storage in Japan February 2017 (Post date:2017.2.22) pdf

Progress in the Intensive Contamination Survey Area

Number of municipalities designated as the Intensive Contamination Survey Area:

104 (at the start) → 94 (at present)
The designation was lifted in seven municipalities due to the radiation dose decrease, etc.

Municipalities that formulated decontamination implementation plans:

93 municipalities (all that had intended to do)

Municipalities that have completed or almost completed their plans (and continued monitoring of air dose rates).

58 municipalities

Municipalities in process of implementing decontamination based on the plans:

35 municipalities
In most of the decontamination plans , it will be completed within FY2016.

The progress of decontamination

•In Fukushima Pref. (as of the end of Dec. 2016):

residential houses: almost completed / Public facilities, farmland & meadows: approx. 90%
Roads / Forests in living area: approx. 70%

•Outside Fukushima Pref. (as of the end of Dec. 2016):

Residential houses: almost completed
Schools & nurseries/ parks, sports facilities / Roads / Farmland & meadows/ forests in living area: completed

For more detail and recent information, please check the progress sheet;

Progress on Off-site Cleanup and Interim Storage in Japan February 2017 (Post date:2017.2.22) pdf

Effects of Decontamination Work in Kawauchi

Air dose rate at the height of 1m from the ground at entire Kawauchi village*

Air dose rates at residential areas :

  • decreased approx. 45% comparing before decontamination to after decontamination
  • decreased approx. 63% comparing before decontamination to post-decontamination monitoring

and the effects of decontamination have been retained

*entire Kawauchi village: indicates both former “Areas in Which Residents are not Permitted to Live” and former “Areas to Which Evacuation Orders are Ready to be Lifted”

Transition of the Air Dose Rates at and around Fukushima

The air dose rates have been decreasing by decontamination work and radioactive decay.

Note: Made by MOE based on the NRA’s “monitoring information of environmental radioactivity level”

Summary on the Decontamination Effect

Effect of decontamination work by the national and local governments (Major results)

*1: Range from 25 to 75 percentile values of the air dose rate.
*2: Data measured at 50cm height in children’s living environment is not included.
*3: Average reduction rate of the air dose rate for different dose levels before decontamination.
(Reduction rate (%)= (1-air dose rate after decontamination / air dose rate before decontamination) x100.)
*4: Released in “Announcement on 'Effectiveness of decontamination work which is implemented by the national government and relevant municipalities in decontamination project' (Jan. 18, 2013)”

Image of Satoyama Restoration Model Project

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