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 Special Decontamination Area(as of the end of November 2016)

Municipalities in which evacuation order 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

Main Topic

  • Decontamination in Progress with max. 11,200 labor per day (Nov. 1 - Nov. 30, 2016)

1. Municipalities implementing whole area decontamination(aimed to complete all the decontamination by March 2017)

  Securement of TSS
Note 1
Consent on decontamination Execution rate(%)
Note 2,3
Residential area Farmland Forest Road
Secured Almost completed 96 76
Tomioka Secured Completed 100 100
100 99.9
Namie Secured Almost completed 93
96 87
Iitate Secured Almost completed 100 100

2. Municipalities completed decontamination

  Time of Completion
Note 4
Tamura June 2013
Naraha March 2014
Kawauchi March 2014
Okuma March 2014
Katsurao December 2015
Kawamata December 2015
Futaba March 2016
Note 1: The ratio shows: Contracted TSS area / Necessary TSS area. It might change due to increase and decrease of the necessary area depending on the progress of decontamination construction.
Note 2: Implementation ratio: Decontamination-completed area / Target decontamination area. They might be both revised with future investigation. “Areas where it is anticipated that residents will face difficulties in returning for a long time” are basically not included.
Note 3: Numbers in () are the numbers in a previous month. Numbers without () have not been changed from the previous month.
Note 4: Time of decontamination completion means the time which decontamination is completed in the area with residents’ consents. If the area is not decontaminated, it will be eventually decontaminated once the consent is obtained.

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

Progress on Off-site Cleanup and Interim Storage in Japan December 2016 (Post date:2016.12.19) 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).

53 municipalities

Municipalities in process of implementing decontamination based on the plans:

40 municipalities
In most of the decontamination plans , ending time period is set between FY2015- FY2016.

The progress of decontamination

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

Public facilities, residential houses, farmland & meadows: approx. 90%
Roads, Forests in living area: approx. 60%

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

Schools & nurseries/ parks, sports facilities / residential houses / Roads: almost completed
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 December 2016 (Post date:2016.12.12) 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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