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Decontamination/reduction of radiation dose and reduction of radiation exposure

Reducing the exposure of workers is a very important issue as they perform decontamination tasks within the power plant site and within the reactor buildings, so we are working to shield and remove sources of radiation, in addition to decontaminating the site, buildings and structures.

Dose rates within the power plant site have been greatly reduced by removal of contaminated debris and soil, decontamination and dose rate reduction of facings, etc., so that the work environment for workers has been improved.

On the other hand, dose rates within the reactor buildings remain high, and access for survey work on the inside is limited, so we are studying measures to decontaminate and reduce dose rates for specific work areas and access routes, and working to develop and utilize equipment and machines that utilize remote technology.

Also, in order to prevent expansion of contamination of the ocean, we are studying such things as construction of impermeable walls, setting up fibrous adsorbent purification equipment, and lining and purification systems within the harbor.

 Furthermore, we are studying development of unmanned radiation monitoring technology to evaluate the environmental impact, and optimization of protective equipment to reduce exposure as part of work environment improvement.

R&D efforts

Ongoing projects

Development of Technology for Improving the Environment inside the Reactor Building (Project of Decommissioning and Contaminated Water Management)
Summary

To further expand the scale of fuel debris and reactor internal structures removal, we will develop technologies related to environmental improvement necessary for safe and efficient work in the reactor building where the damage status due to the accident remains unknown and the dose rate is still high.

Action
  • Development of technology for improving the environment inside the reactor building
    Development of environment / dose distribution digitization technology for exposure reduction
  • Development of evaluation method for deterioration status of skeleton / equipment
    Development of corrosion control technology by electric corrosion protection of suppression chamber support columns
Implementation plan

Targeted process:Development of Technology for Improving the Environment inside the Reactor Buildin

Source:FY 2022 Research and Development Plan for Decommissoning
    (METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment (January 27, 2022))
(PDF page 4-5)

Results & performance by fiscal year
  • FY 2021
Reducing dose rate within the site
Prevention of expansion of contamination of the ocean
Evaluation and monitoring of environmental impact
Study of optimization of protective equipment to reduce exposure (Work environment improvement )

Plant investigation, measurement data, and information

Dose rate reduction within the site
  • Efforts to reduce the environmental dose rate (Updated August 1, 2022)
    (METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment)
Evaluation and monitoring of environmental impact
  • Radiation monitoring using manned helicopter
  • Monitoring of radioactive cesium concentration in river water
  • Detection of Alpha Ray Radiating Nuclide
  • 3D Visualization of Distribution of Radioactive Materials
  • Collection of monitoring data
Optimization of protective equipment to reduce exposure (Work environment improvement)