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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.

Results and Effects of Decontamination

Result in the Special Decontamination Area

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
Okuma Town April 10, 2019
Futaba Town March 4, 2020

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 City March 2017
Namie Town 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 March 4, 2020
Kawamata 360 600ha 510ha 71ha March 31, 2017
Katsurao 460 570ha 660ha 95ha June 12, 2016
Okuma 180 170ha 160ha 31ha April 10, 2019
Kawauchi 160 130ha 200ha 38ha Former Preparation Areas for
lift of Evacuation Order :
October 1, 2014 Former
Habitation Restricted Areas:
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

Result in the Intensive Contamination Survey Area

The progress of decontamination

Whole area decontamination on the Act on Special Measures was completed on March 19, 2018 except in Difficult-to-Return Zones.

•In Fukushima Prefecture (as of March 19, 2018):

Residential houses / Public facilities / Roads / Farmland & meadows / Forests in living areas: Completed in all categories

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

Residential houses / Schools & nurseries/ Parks, sports facilities / Roads / Farmland & meadows/ Forests in living areas: Completed in all categories

Effects of Decontamination in SDA

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

NOTE: The chart shows the air dose rate average in each category (aggregated data of measuring points).
Residential areas include schools, parks, cemeteries, and large-sized facilities, farmland includes orchard, and forests include slopes, grassland and lawn.
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

[Implementation period]

  • Monitoring before decontamination: Nov.2011 - Nov. 2016
  • Monitoring after decontamination: Dec. 2011 - Dec. 2017
  • Post decontamination monitoring: Oct. 2014 - Aug. 2018

Transition of the Air Dose Rate

Compared air dose rate of 7months after the accident (as of November 2011) with that of 91months after the accident (as of October 2018), the latter decreased by 74%. It was confirmed that the decrease was faster than natural attenuation as an overall tendency

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

Result of airborne monitoring in and around Fukushima Prefecture ( NSR / as of March 8, 2019)

Progress of Land Restoration in Temporary Storage Sites (TSS)

  • Currently, the volume of removed soil stored in Fukushima Prefecture has decreased to approx. 6.7 mil. m3.
    *It is the volume as of the end of April 2020 in SDA and as of the end of March 2020 in ICSA, calculating a bag as 1 m3.
  • 194 TSS are planned to complete land restoration by the end of March 2020 and in FY2020 MOE will aim to restore land in about 280 TSS.

Progress in Specified Reconstruction and Revitalization Base (SRRB)

  • In all 6 municipalities (Futaba, Okuma, Namie, Tomioka, Iitate and Katsurao), demolition of houses and decontamination work have started. Especially, in public facilities such as station square, nurseries, and gymnasium, demolition and decontamination work were completed.
  • Towards the goal of lifting evacuation order at entire SRRB in Spring of 2022-2023, MOE is conducting demolition and decontamination cooperating with relevant ministries

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