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Ensuring safety for fuel debris retrieval (1) (Structural integrity)

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

Completed projects

Development and Management of Evaluation Method of Seismic Performance/Impact of RPV and PCV (Project of Decommissioning and Contaminated Water Management)
Summary

We performed impact assessment on large equipment in the event of a major earthquake, in consideration of the current situation, and retrieval situation (including medium term situation) for fuel debris retrieval over the long term. We also performed proof stress and seismic load assessment, and earthquake response analysis for important equipment, paying attention to the pedestal and S/C supports, mainly to develop seismic resistance/impact assessment methods. In order to achieve further upgrade of the assessment method that we have developed, we verified confirmation methods of analysis and test houses based on actually possible seismic resistance and requirements.

Action items
  1. Establishment of safety scenario in the case of large scale earthquake
  2. Development of seismic resistance/impact assessment method to establish safety scenario
    • Development of seismic resistance/impact assessment method for pedestal and pressure control room supports
    • Proof stress and seismic load evaluation
    • Earthquake response analysis
  3. Enhancement of safety scenario
Implementing organizations

Implemented by IRID.

Implementation plan

Target process: Development and management of evaluation method of seismic performance/Impact of RPV and PCV

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 13)

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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Development of Corrosion Inhibition Technology for RPV and PCV (Project of Decommissioning and Contaminated Water Management)
Summary

We performed electrochemical measurements of component materials in a solution to which we had added the corrosion inhibitors that were selected based on the results of corrosion tests. We performed un-irradiated corrosion tests and corrosion tests under gamma irradiation, assessed them for the possible generation or progression of local corrosion, and selected corrosion inhibitors that had applicability to actual equipment. Also, based on overall impact assessment of existing water treatment equipment systems that used corrosion inhibitors, and impact assessment on adsorptivity related to the concentration of corrosion inhibitors, we created an overall plan and control requirements for a corrosion countermeasures system.

Action items
  1. Effect/impact assessment for corrosion control measures
  2. Conceptual design of corrosion control system
Implementing organizations

Implemented by IRID.

Implementation plan

Target process: Development of corrosion inhibition technology for RPV and PCV

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 25, 2016))
(PDF page 18)

Results & performance by fiscal year
  • FY 2016

R&D efforts (related basic and generic research)

Steel structure corrosion, corrosion prevention (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)
Concrete structure assessment (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)

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, June 10, 2020) new

(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 (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>