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Comprehensive analysis and evaluation of fuel debris and FP status

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

Ongoing projects

Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Project of Decommissioning and Contaminated Water Management)
Summary

To develop technology necessary for quantitative analysis of components and estimation of characterization of fuel debris in order to contribute to the development of methods for retrieval of fuel debris and internal structures and technologies for containing, transportation and storage of fuel debris etc.

Action items
  1. Development of Technology Necessary for Analysis and Estimation of Fuel Debris Characteristics
  2. Development of abbreviated analysis and non-destructive technology of fuel debris
Implementation plan

Targeted process：Development of Analysis and Estimation Technology for Characterization of Fuel Debris

Source: FY 2024 Research and Development Plan for Decommissioning
　　　　(METI, Secretariat of the Team for Countermeasures for Decommissioning and Contaminated Water Treatment (February 29, 2024)) (PDF page 7-9)

Results & performance by fiscal year
  • FY 2022
  • FY 2022
  • FY 2021
  • FY 2020
  • FY 2019
  • FY 2018
  • FY 2017
  • FY 2016
  • FY 2015
  • FY 2014
  • FY 2013
  • FY 2012
Results & performance for individual projects, etc. (Archives)

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Estimation of condition of core, PCV (TEPCO)
  • Estimation of condition of core, PCV at Fukushima Daiichi NPS Units 1 to 3, and study of unsolved problems
    　 With the objective of making continuous improvements to progress in decommissioning work and nuclear power station safety technology, we are in the process of extracting, investigating and studying 52 unchecked and unsolved problems on detailed development mechanisms after the accident occurred. We are releasing a report to summarize the results achieved from that study so far.
  • Fukushima Daiichi NPS accident background and lessons
    　We are in the process of investigating and analyzing the progression of the accident at TEPCO’s Fukushima Daiichi NPS, and here we explain the lessons we learned from that analysis and the accident.

Completed projects

Upgrading Level of Grasping State inside Reactor (Project of Decommissioning and Contaminated Water Management)
Summary

We performed comprehensive analysis and assessment of fuel debris within reactors and fission product (FP) to attain a firmer understanding of them, in order to contribute to decision on method for fuel debris retrieval, and to confirm the stable condition of the plant. Specifically, we performed comprehensive analysis and assessment of conditions inside the reactor in order to obtain necessary data and information of fuel debris, and location and distribution of FP for each reactor, as well as the impact on integrity of PCV and structures in the reactor, criticality assessment, and FP behavior during retrieval. After performing that analysis and assessment we did sensitivity analysis and reverse analysis for each event, which were judged to be important for improving the reliability of the results of the analysis and assessment.

Action items
  1. Comprehensive analysis/evaluation of the conditions inside the reactors
  2. Estimation/evaluation of fuel behavior and features of debris and fission products
Implementation organization

　Implemented by IRID and the Institute of Applied Energy.

Implementation plan

Targeted process: Upgrading level of grasping state inside reactor

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 (February 23, 2017)) (PDF page 3)

Results & performance by fiscal year
  • FY 2017
  • FY 2016
  • FY 2015
  • FY 2014
  • FY 2013
  • FY 2012
Results & performance for individual projects, etc. (Archives)

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  • Assessment by using accident progression analysis codes

R&D efforts (related basic and generic research)

Analysis of debris properties, and processing 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)
Technology to measure nuclear material within fuel debris (Research by JAEA: Study of concomitant characteristics of nuclear materials of fission product in measurements of nuclear material using passive gamma measurement) (PDF)

Plant investigation, measurement date, and information

Efforts to understand the plant status at each of Units 1 to 3, and for fuel debris retrieval (December 4, 2024)

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

Plant-related parameters
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 (PDF・Word file)
Collection of links to data on in-core situation ( January 8, 2020) 
Chronology (Events after the accident, in-core situation, etc.)(Updated regularly, September 2018)

Other related information

Fukushima Daiichi NPS accident background and lessons: Estimations of the accident progression at each Unit (“Why did the accident occur?” and “Accident background”) (TEPCO)
  • Accident background
  • Accident process
TEPCO Fukushima Daiichi NPS accident-related technology workshop
  • Guidance materials
  • Lecture materials