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 April 1, 2017)

Municipalities in which evacuation orders were lifted

Municipality Evacuation order was lifted on
Tamura city April 1, 2014
Kawauchi village October 1, 2014*1/June 14, 2016*2
*1:Former Areas to which evacuation orders are ready to lift up
*2:Former Areas in which residents are not permitted to live
Naraha town September 5, 2015
Katsurao village June 12, 2016
Minamisoma city July 12, 2016
Iitate village March 31, 2017
Kawamata village March 31, 2017
Namie town March 31, 2017
Tomioka town April 1, 2017

Municipalities in which whole area decontamination were completed

Municipality Completion of decontamination
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
Minamisoma March 2017
Namie March 2017

Completion of the Decontamination in SDA (as of the end of March 2017)

Municipality Residential area Farmland Forest Road Evacuation order was lifted on
Number of implementated houses Implemented area ha Implemented area ha Implemented area ha
4,500 1,700ha 1,300ha 270ha July 12, 2016
Namie 5,600 1,400ha 390ha 210ha March 31, 2017
Tomioka 6,000 750ha 510ha 170ha April 1, 2017
Iitate 2,000 2,100ha 1,500ha 330ha March 31, 2017
Futaba 97 100ha 6.2ha 8.4ha -
Kawamata 360 600ha 510ha 71ha March 31, 2017
Katsurao 460 570ha 660ha 95ha June 12, 2016
Okuma 180 170ha 160ha 31ha -
Kawauchi 160 130ha 200ha 38ha Former Areas to which evacuation
orders are ready to lift up:
October 1, 2014
Former Areas in which residents are
not permitted to live:
June 14, 2016
Naraha 2,600 830ha 470ha 170ha September 5, 2015
Tamura 140 140ha 190ha 29ha April 1, 2014
Total Number 22,000 8,500ha 5,800ha 1,400ha  
  • ”Forest” means that is close to residential area
  • MOE will continue decontamination if we get new consents from the residents

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

Progress on Off-site Cleanup and Interim Storage in Japan May 2017 (Post date:2017.5.18) pdf

Progress in the Intensive Contamination Survey Area

※Progress of the whole area decontamination as of the end March of 2017

Number of municipalities designated as the Intensive Contamination Survey Area:

104 (at the start) → 92 (at present)
The designation was lifted in 12 municipalities due to the radiation dose decrease, etc.

Municipalities in which the progress is 100%:

80 municipalities

Municipalities in process of implementing decontamination based on the plans:

12 municipalities

The progress of decontamination

•In Fukushima Pref. (as of the end of Jan. 2017):

residential houses: almost completed / Public facilities, farmland & meadows: approx. 90%
Roads / Forests in living area: approx. 80%

•Outside Fukushima Pref. (as of the end of March 2017):

Residential houses / 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 May 2017 (Post date:2017.5.18) pdf

Effects of Decontamination Work

Air dose rate at the height of 1m from the ground / Transition according to land category

The chart shows air dose rate average in each category (aggregated data of measuring points).
Post-decontamination monitoring was implemented after 6 months to a year after the decontamination work.
The latest result of post-decontamination monitoring in municipalities were summarized (the first or the second)

[Implementation period]

  • Monitoring before decontamination : Nov. 2011 - July 2016
  • Monitoring after decontamination : Dec. 2011 - Sep. 2016
  • Post decontamination monitoring : Oct. 2014 - Dec. 2016

Whole SDA

*Only in areas with the data, excluding Areas where it is expected that the residents have difficulties in returning for a long time

Transition of the Air Dose Rate

Compared air dose rate of 7months after the accident (as of Nov. 5, 2011) with that of 67months after the accident (as of Oct. 15, 2016), 71% decrease was found. This figure showed the decrease was faster than natural decay

Distribution map showing transition of the air dose rate within 80km radius

Result of airborne monitoring in and around Fukushima Prefecture (as of February 13, 2017, NSR)

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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