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Technological development for decommissioning

Decontamination and reducing radiation exposure

Develop remotely controlled decontamination techniques indispensable for reducing the exposure of workers engaging in work in reactor buildings

Decontamination robots developed in a subsidized project (used for the decontamination work for the lower elevations of the first floor of reactor buildings)

Decontamination robots
Decontamination robots under development in a subsidized project (used for decontamination work for second and third floors of reactor buildings)

Back to the Contaminated Water and Decommissioning Issues Portal Website

Internal Investigation of Nuclear Reactors

Investigate locations and distribution, etc. of the fuel debris inside the reactor pressure vessels

Example 1: Survey using cosmic ray muons (Muon Transmission Method)

Picture of internal investigation of a reactor using cosmic ray muons
(Investigation utilizing the characteristics of cosmic ray muons that lose energy when going through a substance)

Data obtained on the northwestern side of Unit 1 (monitored for 96 days)

Equipment for the Muon Transmission Method was installed at Unit 2. (Mar. 17, 2016)

Ascertaining Locations of Fuel Debris inside the Reactor by Muon Measurement at Unit 2 of Fukushima Daiichi NPS (linked to TEPCO’s website)external linkPDFfile

Example 2: Internal investigation of the reactor containment vessels (using robots)

A robot for the internal investigation of reactor containment vessels

Internal Investigation of the Containment Vessel at Unit 1 was Carried out in April 2015 (linked to TEPCO’s website)external link

Back to the Contaminated Water and Decommissioning Issues Portal Website

Repair of Containment Vessels

Discuss appropriate methods for stably maintaining the status inside the reactor containment vessels while filling them with water from the perspective of providing shielding from radiation from the fuel debris and radioactive materials attached to core internals, preventing the scattering of dust upon cutting and transportation, and continuing to cool the fuel debris


(*) Fuel debris locations are examples of potential, actual locations now being surveyed.


A robot going underwater to search for leaks in reactors


A robot with a hanging camera to search for leaks in reactors


A demonstration is planned to check water-proofing performance by actually pouring concrete materials into a model representing the lower part of the reactor containment vessel.

(Reference) Naraha Remote Technology Development Center (linked to the Japan Atomic Energy Agency’s website)external link

Back to the Contaminated Water and Decommissioning Issues Portal Website

Ascertaining of the Property of the Debris

Ascertain the status of the fuel debris in the reactors, consider means to retrieve, store and preserve the fuel debris, and develop technologies necessary for analysis of fuel properties and measurement of the melted fuel
Experiment to create simulated debris to survey its properties
Experiment to create simulated debris to survey its properties

Back to the Contaminated Water and Decommissioning Issues Portal Website

Retrieval of Debris

Develop technologies concerning retrieval methods and equipment; controlling technology to prevent recriticality upon retrieval; and technologies for the storage, transport and preservation of retrieved fuel debris, for the purpose of retrieval of the fuel debris

Three fuel debris retrieval methods were selected for implementation in the “Technical Strategic Plan 2015 for Decommissioning of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company” compiled by the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF)external link

(1) Access to fuel debris from the top of the PCV (submerged underwater)

Method of filling a containment vessel with water and retrieving fuel debris from the top of the containment vessel
Challenging issues include water containment, the quake resistance of the containment vessel, and criticality control.

(2) Access to fuel debris from the top of PCV in the air (exposed)

Method of retrieving fuel debris in the air from the top of the containment vessel (without filling the containment vessel with water)
Challenging issues include the prevention of the spread of radioactive dust, radiation shielding, etc.

(3) Access to fuel debris from the side of PCV in the air (exposed)

Method of retrieving fuel debris in the air from the side of the containment vessel (on the first floor of the reactor building) (without filling the containment vessel with water)
Challenging issues include the prevention of the spread of radioactive dust, radiation shielding, etc.

Technical Strategic Plan for Decommissioning of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company (linked to the website of the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF))(in Japanese)external link


A remotely operated arm (trial model)

(Reference) Management Office for the Project of Decommissioning and Contaminated Water Management

The Mitsubishi Research Institute has been serving as the secretariat for the subsidized project concerning contaminated water and decommissioning issues under the FY2013 supplementary budget and the FY2014 supplementary budget (consigned by the Agency for Natural Resources and Energy).

(Reference) Progress of the R&D project

Back to the Contaminated Water and Decommissioning Issues Portal Website

Division in Charge

Nuclear Accident Response Office, Agency for Natural Resources and Energy

 
Last updated:2016-08-29
Ministry of Economy, Trade and Industry
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