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Development of method and system for fuel debris retrieval

R&D efforts (Application development linked to plant applications and actual use)

Ongoing projects

Development of Technologies for Retrieving Fuel Debris and Internal Structures (Project of Decommissioning and Contaminated Water Management)
Summary

We develop elemental technologies required for equipment/device/system for retrieval of fuel debris and internal structures, and for ensuring safety during the work for retrieval of fuel debris based on development results so far, and perform the test.

Action items
  1. Development of retrieval method of fuel debris
  2. Development of technologies for handling fuel debris
    2.1 Development of dust collection/collection system of fuel debris in PCV
    2.2 Development of cleaning/processing technologies of fuel debris and deposits in liquids
    2.3 Survey on technologies for sorting out fuel debris and waste
  3. Development of technologies for ensuring safety during the work for retrieval of fuel debrisl
    3.1 Development of elemental technologies relating to containment functions
    3.2 Development of elemental technologies for criticality prevention and monitoring
Implementing organizations

 Implemented by IRID, ONET TECHNOLOGIES, Joint Stock Company "TENEX".

Implementation plan

Targeted process: Development of technologies for retrieving fuel debris and internal structures

Source: FY 2019 Research and Development Plan for Decommissioning
    (METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment (February 28, 2019))
(PDF page 12)

Results & performance by fiscal year

<Updated regularly>

Results & performance for individual projects, etc. (Archives)

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<Updated regularly>

Predecessor project (1): (2nd stage) Advancement of Retrieval Method and System of Fuel Debris and Internal Structures (Project of Decommissioning and Contaminated Water Management)
Summary

In technologies for advancement of retrieval method and system of fuel debris and internal structures, we develop technologies to solve the problem extracted as aresult of concept study, and carry out elemental test as needed.

Action items
  1. Technology development about containment function
    • Technology development for ensuring of containment function
    • Technology development about exposure reduction
  2. Technology development about collection/removal of dust derived from fuel debris
    • Technology development for reduction/removal of radioactive substance in air
    • Technology development for reduction/removal of radioactive substance in water
  3. Study on monitoring system of α nuclide by fuel debris retrieval
    • Concept study on detection technology and system of α nuclide in air and making of development plan
    • Concept study on detection technology and system of α nuclide in water and making of development plan
  4. Technology development about establishment of criticality control method
    • Technology development for measurement of subcriticality and subcriticality monitoring
    • Technology development about detection of recriticality
    • Development of criticality prevention technologies
  5. Optimization study on safety ensuring of method and system
Implementing organizations

 Implemented by IRID.

Implementation plan

Targeted process: Advancement of retrieval method and system of fuel debris and internal structures

Source: Progress status of R&D projects and direction for next period
    (METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment (March 1, 2018))
(PDF page 9)

Results & performance by fiscal year
  • FY 2017
  • FY 2017
  • FY 2016
  • FY 2015
  • FY 2014
Results & performance for individual projects, etc. (Archives)

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Predecessor project (2): (1st stage) Upgrading Approach and System for Retrieval of Fuel Debris and Internal Structures (Project of Decommissioning and Contaminated Water Management)
Summary

We organized the most recent data and information related to conditions including plant information that is necessary to decide policies for retrieval of fuel debris and structures from reactors. We also studied feasibility of all three methods, including submersion method, submersion top-access method, and partial submersion side-access method, and maked conceptual designs for systems within the necessary scope. We also designed retrieval equipment and creating development plans for the three methods.

Action items
  1. Condition setting to determine retrieval method policy
  2. Study on fuel debris retrieval method, system and equipment
    • Feasibility study of method
    • Conceptual study on system
    • Design study on equipment
  3. Establishment of development plan for fuel debris retrieval system/ equipment
  4. Development of fuel debris sampling technology
Predecessor project (3): Development of technology for retrieval of fuel debris and structures within reactors (Project of Decommissioning and Contaminated Water Management)
Summary

We have thoroughly looked at “all kinds of conditions and plant information” that is necessary to decide the method for retrieval of fuel debris and structures from reactors. We have also studied a wide range of scenarios and choices for fuel debris retrieval, and have organized the information and created appropriate formats, such as flow charts, for plans and decision criteria in order to make a final decision on the retrieval method for each plant.

Action items
  1. Setting all conditions for retrieval method policy decision
  2. Creating development plans, etc., for related component technology
    • Investigation and study of existing technology
    • Creation and updating of development plan
    • Component tests and technology development
    • Assessment of applicability to actual equipment, mockup tests
  3. Study of fuel debris retrieval method, system and equipment
Predecessor project (4): Advancement of Fundamental Technologies for Retrieval of Fuel Debris and Internal Structures (Project of Decommissioning and Contaminated Water Management)
Summary

We develop necessary elemental technologies based on past study results about retrieval method of fuel debris and internal structures. also, develop remote maintenance technology for retrieval equipment of fuel debris and internal structures.

Action items
  1. Development of common fundamental technologies concerning retrieval of fuel debris and internal structures
    1.1 Technology development for prevention of dust diffusion
    • Development of collection system of fuel debris
    • Development of cutting/dust collection system of fuel debris
    • Development of prevention method of dust diffusion
    1.2 Elemental technology development for setting of retrieval equipment
    • Development of setting method of work cell
    • Development of obstacle removal technology at the time of fuel debris retrieval
    1.3 Development of monitoring technology at the time of fuel debris retrieval
  2. Development of remote maintenance technology for fuel debris retrieval equipment
Implementing organizations

 Implemented by IRID, Hamamatsu Photonics, K.K., ONET Technologies CN(Comex Nucleaire), RosRAO, FSUE.

Implementation plan

Targeted process: Advancement of fundamental technologies for retrieval of fuel debris and internal structures

Source: Progress status of R&D projects and direction for next period
    (METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment (March 1, 2018))
(PDF page 11)

Results & performance by fiscal year
  • FY 2018
  • FY 2017
  • FY 2016
  • FY 2015
Predecessor project (5): Development of Fundamental Technologies for Retrieval of Fuel Debris and Internal Structures (Project of Decommissioning and Contaminated Water Management)
Summary

We developed and assessed the necessary component technologies in order to assess the feasibility of each of the three methods, the submersion method, the submersion-top accessmethod, and the partial submersion side-access method. This project was split between overall proposal businesses and partial proposal businesses, in which overall proposal businesses and partial proposal businesses conducted necessary component tests to ascertain feasibility of the methods, then overall proposal businesses performed overall organization of the component tests and analyzed results of component tests.

Action items
  1. Component test required to assess feasibility of method
    • Technology to prevent expansion of contamination during retrieval of large structures
    • Technology to prevent expansion of contamination during fuel debris retrieval inside PCVs
    • Technology for access to fuel debris
    • Remote work technology for fuel debris retrieval
    • Technology to prevent expansion of contamination during fuel debris retrieval
    • Technology to reduce exposure for workers engaged in fuel debris retrieval
    • Technology related to cutting and dust extraction during fuel debris retrieval
    • Tests of monitoring technology during fuel debris retrieval
  2. Analysis of elemental test results

Completed projects

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Conceptual study of alternative fuel debris retrieval methods and study of feasibility of component technologies (Project of Decommissioning and Contaminated Water Management)
Summary

We did conceptual studies of open-air methods to retrieve fuel debris safely and surely. We also did feasibility studies of monitoring instruments with light, compact illumination functions that can be used for interior monitoring even in high-dose rate conditions, and of measurement instruments to identify fuel debris. Then we did feasibility studies of equipment that is capable of cutting fuel debris (including dust extraction functions).

Action items
  1. Conceptual study of alternative fuel debris retrieval methods
  2. Study of feasibility of monitoring and measurement technologies for alternative methods
  3. Study of feasibility of fuel debris cutting and dust extraction technologies for alternative methods
Implementing organizations
  • Conceptual study of alternative fuel debris retrieval methods project
  • IHI Corporation
  • AREVA ATOX DA&D SOLUTIONS
  • Cavendish Nuclear Ltd, BGE K.K., Shimizu Corporation
  • Public Interest Incorporated Foundation Radwaste and Decommissioning Center, Kimura Chemical Plants Co., Ltd., General Incorporated Foundation Japan Clean Environment Promotion Organization
  • Study of feasibility of monitoring and measurement technologies for alternative methods project
  • QI Inc.
  • Create Technologies Limited, Oliver Crispin Robotics Limited
  • Hamamatsu Photonics, K.K.
  • Fujikura Ltd.
  • Study of feasibility of fuel debris cutting and dust extraction technologies for alternative methods project
  • IHI Corporation
  • ONET TECHNOLOGIES NUCLEAR DECOMMISSIONING OTND
  • Taisei Corporation
Results & performance by fiscal year
  • FY 2014
Results & performance for individual projects, etc. (Archives)

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R&D efforts (related basic and generic research)

<Remote technology for inspections and measurements>

Inspection technology development (Decommissioning Basic Research : Human resource development program at Tohoku University - Basic research into reliability maintenance of PCV and buildings, etc., and waste processing and disposal, and core human resource development program for decommissioning)
Remote technology (Decommissioning Basic Research: Human resource development program at Tohoku University - Basic research into reliability maintenance of PCV and buildings, etc., and waste processing and disposal, and core human resource development program for decommissioning)
Research on remote operations technology (Decommissioning Basic Research: Human resource development program at University of Tokyo - Comprehensive human resource development for decommissioning based on remote operations technology and nuclide analysis technology) (PDF)
Remote measurement technology (Decommissioning Basic Research: Human resource development program at Tokyo Institute of Technology - Advancements in skilled human resource development for and basic research on decommissioning engineering) (PDF)


<Criticality control related>

Analysis of re-criticality accidents during debris retrieval (Decommissioning Basic Research: Human resource development program at Tokyo Institute of Technology - Advancements in skilled human resource development for and basic research on decommissioning engineering) (PDF)
Measures to ensure sub-criticality during debris retrieval (Decommissioning Basic Research: Human resource development program at Tokyo City University - Advancements in skilled human resource development for and basic research on decommissioning engineering) (PDF)

Plant investigation, measurement data, and information

Efforts to understand the plant status at each of Units 1 to 3, and for fuel debris retrieval (Updated monthly, December 25, 2019)new

(METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment)

Plant-related parameter
Fukushima Daiichi NPS survey map
Common data presented by Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Plant (BSAF) related to accident progression analysis according to OECD/NEA
Information Portal for the Fukushima Daiichi Accident Analysis and Decommissioning Activities
Collection of figures of data on in-core situation (Updated regularly, August 2018)
  • Figures of temperature, dose rate, amount of water injection, etc. in each Unit (PDFWord file)
Collection of links to data on in-core situation (Updated monthly, January 8, 2020)new
Chronology (Events after the accident, in-core situation, etc.) (Updated regularly, September 2018)

Other related information

<Updated regularly>