Decommissioning of the Fukushima-Daiichi NPP
Progress and Issues
International Topical Workshop on Fukushima Decommissioning
Research 2022 (FDR2022)
Oct. 15, 2022
Hajimu Yamana
President, Nuclear Damage Compensation and Decommissioning
Facilitation Corporation (NDF)
Professor Emeritus, Kyoto University©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

1

Contents

Part-1 Reviewing the 11 years after the accident
Part-2 Technical strategic plan, update (2022)
Photo：REUTER, May 19, 2022 (ttps://www.reuters.com/world/asia-pacific/japan-nuclear-regulator-grantsinitial-nod-fukushima-water-release-plan-2022-05-18/) (Originally taken by Kyodo on Mar 17, 2022)

2©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Major Achievements in the Past DecadePart-1
Reviewing the 11 years after the accident
2011

2022

2011

3
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The Organizational Structure for 1F Decommissioning
Since 2011
MOF
Government bondState-backed financial guarantee

NDF

Since 2011 for Compensation
Since 2014 for D&D

Since 2011

The Nuclear Emergency Response Headquarters
Government responsibility for disaster response

Inter-Ministerial Council• Legally authorized organization under thejurisdiction of METI and MEXT
• Shareholder of TEPCO by a majority ofvoting rights

Strategic proposal• Loan to TEPCO to facilitate compensation• Oversight of corporation management

Program oversightCompensation facilitation
D&D facilitation

Supervision andguidance

Decommissioning• Mid & long-term technical strategy for D&D fund management• Decommissioning Fund management• Program and project oversight
Financial assistance• R&D strategy and planningfor compensation• Public outreach

NRA

METI
D&D policy(Roadmap)

Since 2012

Safety regulation for
specified facility

TEPCO・HD

Responsible for

Ensuring stable electricity supply
Compensation to the victims
D&D of 1F site as the licensee
Ensuring finance for D&D andcompensation

Supervision of R&D
Since 2011 METI
Since 2014 MEXT R&D fundSince 2013

Technical support through R&D

Private sectors/JAEA/Universities
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Progress over the Past 11 Years and the Vision for the future
Up to the present
2011 Mar.

Origin: Mid. and Long-term Roadmap

2011 Nov.

2013 Nov.

8 months after the accident

Step-1

Before achieving cold shutdown

Before start of spent fuel removal

Emergency response
Focused all the efforts on ending the crisis
situatione.g. Cooling of damaged cores and spent fuelpools, and stoppage of radioactivity release

Step-2
Before start of fuel-debris retrieval

Stabilization and prepartion for long operation
Gradual decrease of stagnant water in the buildings
Contaminated water treatment and storage of ALPS-treated water
Prevention of contaminated water leak-out with reduction of groundwater leak-in
Spent Fuel removal from Unit-4 and 3
Prepartion of spent fule removal from Unit-1 and 2
PCV internal inspection
Radioactive waste storage and reduction
Study on fuel-debris retrieval methods
Improvement of radiological environment

Forthcoming planca. 10 yrs after start of step-1

ca. 10 yrs after start of step-3

Step-3
Expected to accomplish within 30 to 40 years after the start of Step-1 (2011 End)

Step-3 (1)Step-3 (2)Expanded internal inspection of PCV
Scale up of trial fuel debri retrieval
Preparation for full-scaled fuel debris retrieval

Full-scaled fuel-debris retreaval for Unit-1 to 3
Safe storage of recovered fuel debris and spent fuels
Resolving the contaminated water issue

Completion of spent fuel removal from SFP in all units

Waste management with storage, volume reduction, processing/disposal

Drastic minimization of contaminated water generation
Enhanced waste management through characterization

Preparation for the final disposal of raioactive wastes
Other necessary operations to achieve the goal of D&D

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Overview of the Key Achievements
2011

Accident
Contaminated
Water Management

In-Reactor Inspection

Spent Fuel Removal
Waste Management
Major Dicisions

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

●
● Stopped leak from seawater trench● KURION installed● SARRY installed● ALPS treatment started● Highly contaminated water treatment completed● Frozen wall installed

Implementation Plan for discharging ALPS-treated water approved ●Plan for discharge, approved by the municipalities ●● Camera inserted from penetration (Unit 2)● Camera inserted from penetration (Unit 1)● Observed with muon (Unit 1)● Camera inserted from penetration (Unit 3)● Observed with muon (Unit 2)● Investigation with underwater ROV (Unit 3)● Investigation with hanging camera (Unit 2)
Investigation with underwater ROV (Unit1) ●● Unit 4 Spent fuel removal completed
Unit 3 Spent fuel removal completed ●● Misc. solid waste incinerator installed● Solid waste storage added● Decided decommissioning of Unit 5/6
Reorganized to project-based management●

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How the Released Radioactivity was RelocatedOrigin: Technical Strategic Plan 2022

Spent Fuels

Released Cs-137

2011

2,774 assemblies in total

7x1017 Bq of Cs-137 were2022

About 2/3 has been alreadytransferred to the Common
Spent Fuel Storage Pool

Most has been adhered tothe sorbents and structures

Number of fuel assemblies ofspent fuel (Units 1 to 4)

Radioactivity of Cs-137 released at
the accident (Units 1 to 3)

were stored in SFP of Units 1 to 4

released into the reactor buildings

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Decreasing Trend of the Risks on site

 Most of the risks on siteoriginates from spent fuels
and fuel-debris
 Total SED score has decreased
7 digits over 11 years
 Drastic decrease was achievedby radioactivity decay and SF
removal from Units-3 and 4

Risk level (logarithmic scale)

FD: Facility Descriptor
WUD: waste Uncertainty Descriptor

Risk trend on a logarithmic scale
Rubble removal from Unit 4 operating floor
Fuel removal from Unit 4
Change in evaluation method
Year after the accident

Risk level (linear scale)

SED, a simplified risk index

Origin: Technical Strategic Plan 2022

Risk composition on linear scale
Scale: X10 magnified

Fuel debris

Fuel in SFP

Contaminated water, etc.

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Radioactivity Release to the Environment
Residual heat of the reactor Radioactivity of the reactor

Environmental release of Cs-137 from reactor buildings

By calculation for Unit-3

Immediately
after the accident

Present

0.18%

Immediately
after the accident

セシウム137放出量[億Bq/h]Cs-137
release rate［100MBq/h］

10

100%

0.04%

Hourly release (100MBq/hr)

100%

12

Present86
4
20

2011/4/1
2011

2013/3/31
2013

2015/4/1
2015

2017/4/1
2017

2019/4/2
2019

一般の皆さんも防護具なしで見学できる

Cs-137 inside of the harbor

Cs-137 outside of the harbor
1,000

1～4号機取水口北側
At the pointof the north of cooling wateroutlet of Units 1 to 4

600
400
200
0

● ND
2011

2013

2015

2017

2019

2021

Concentration (Bq/L)

Concentration (Bq/L)

1,000
800

2021/4/2
2021

At the point 5/6号機放水口北側
of the north of cooling wateroutlet of Units 5 and 6

800
600
400
200
0

● ND
2011

2013

2015

2017

2019

2021

9
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Techniques Adopted to Probe Inside of the Reactor
 Observation inside the reactor building with mobile robots
 Use of existing reactor instrumentation and reinforcementof condition observations
PCV radioactivity concentration, hydrogenconcentration
bottom of PCV/RPV, temperature, PCV pressure, waterlevel
 Estimation inside reactor by water injection stop testing Imaging with muon tomography
 Estimation inside reactor by core-disruption simulation
 Internal inspection by inserting a camera(U1: once, U2: 5 times, U3: once)
 Internal inspection with mobile robots(Once per Unit) Full mobile inspection (U1/ROV) Full remote arm inspection (Unit 2/trial)
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“The Long and Winding Road” to Reach a Convincing Understanding
Quantitative
Information
Acquisition

Qualitative
Understanding
Situational
Understanding

Muon
Tomography

Estimation

Computer
Simulation

Elucidation of
Observed
Instrumentation
Signals with
their Trends

PCVInspection
with ROVs

PCVInspection
through
Penetration
with Inserted
CameraPCVInspection
with ROV(U-1) 2022

PCVInspection
with LongArm (U-2)
2023

In-Building Inspection
with Robots or Human

Degree of Access to Core

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Government’s Funds to Support 1F R&D

METI Amount of Awarded Money

Structure of Government-led R&D
METI

MEXT

The Government-led R&D
Program on Decommissioning
and Contaminated Water
Management

The Center of the WorldIntelligence Project for
Nuclear Science & Technology
and Human Resource
Development

Subsidyfor R&D

R&D
Planning

NDF

Information
Exchange

Subsidy for
Basic ResearchTechnical Companies*

Research
Fund

Universities

Technological Contribution

TEPCO Fukushima-Daiichi*: IRID (International Research Institute for
Nuclear Decommissioning) ; A consortium isfounded by some Japanese organizations

In-Reactor Inspection
Fuel-Debris Retrieval
Waste Management
Spent Fuel Storage
Contaminated Water Management

50
40
30

Unit: Billion Yen

20
10
0

JAEA

R&D
Coordination

Cumulative money awarded

602014 2015 2016 2017 2018 2019 2020
About 100 B yen, invested for installing new facilities

2021

MEXT Number of Awarded Researches
100
90
80
70
60
50
40
30
20
10
0

Cumulative number of researaches

Institute/Company
University

2014

2015

2016

2017

2018

2019

2020

2021

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Major Achievements in the Past DecadePart-2
Technical strategic plan, update (2022)
Released, Oct. 11, 2022

Acknowledged Documents Supporting 1F D&D
Government
NDF
NDF&TEPCO
TEPCO

Mid-and-Long-term Roadmap
Technical Strategic Plan
Withdrawal Plan for Reserve Fund
Mid-and-Long-term Decommissioning Action Plan
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Variation of the Risk Profile of 1F Site

Origin: Technical Strategic Plan 2022

Change in the Risk map(Compared with the evaluation of 2018, the oldest evaluation using the same method)••

Risk reduction : Removal of Spent Fuel in Unit 3 SFP, treatment of stagnant water in buildings andresidual water in tanks
Separation of risk sources that require specific measures : zeolite sandbags and ALPS slurry (HIC to betransferred）
Technical Strategic Plan 2022

Hazard Potential (logarithmic scale)Hazard Potential (logarithmic scale)Technical Strategic Plan 2018

Safety Management (logarithmic scale)Color-coding of risk
sources withreference to the Midand-Long-term
Roadmap *Safety Management (logarithmic scale)・Hazard potential : an index of the impact of internal radiation exposure

・Safety Management : an index of the likelihood that an event will occur

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Risk Reduction Flow in the D&D Process

Origin: Technical Strategic Plan 2022

How the risk sources have changed (will change) to the “Sufficiently stable
management” compared with the time of the accident

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Operation of Trial Retrieval (internal investigation and fuel debris sampling) in Unit 2
Carriage
Link
Telescopic arm

Photo quoted from TEPCO’s Website

Photo quoted from IRID’s HP

 Trial retrieval (internal investigation and fuel debris
sampling) is a series of operations, and fuel debris
sampling is one part of 11 steps.
 After opening the hatch of the penetration X-6 andextending the containment barrier outside the PCV,
it is important to ensure containment as the inside ofthe enclosure becomes progressively contaminated.
 For on-site applications with uncertainty, thechallenges are to ensure functionality verification
under various conditions and equipment can be
rescued in case of emergency.
 It is necessary to ensure that the required conditions are
satisfied by conducting mock-up tests.
 Due to the uncertainty of the PCV internal situation,
work must be performed safely and carefully, keeping in
mind that things may not go as planned.

Robot-arm in mock-up testing(1) Preparatory work (completed)(2) Installation of isolation chamber (in progress)(3) Opening of the hatch of penetration X-6 byhatch opener(4) Removal of deposits in penetration X-6 bydeposit remover(5) Robot arm installation(6) Robot arm entry(7) Internal investigation by robot arm and fueldebris sampling(8) Collect from fuel debris retrieval equipment totransport container, and dose measurement(9) Acceptance and measurement of gloveboxes(10) Removal of containers, storage in shipping
containers, and carry-out(11) Off-site transport and off-site analysis(analysis of fuel debris properties)

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Study on the Concept with Good Potential for the Full-Scale Fuel Debris Retrieval

Origin: Technical Strategic Plan 2022

Conceptual drawing of the current
partial submersion (dry) method

Conceptual drawing of thesubmersion method (shell structure)

・This candidate partial submersion (dry)method does not use the upper or side
access method alone but combines them,which has been examined previously.

・This candidate submersion method uses a
new idea to submerge the reactor building
by enclosing the entire reactor building witha new structure called a shell structure as aboundary (shell method).

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Basic Policy for the Waste Management Challenge

Origin: Technical Strategic Plan 2022

Challenges and technical strategies
Characterization

 For a variety of solid waste, it is needed todevelop a medium-to-long-term analysis
strategy that defines its priority, the objective of
the analysis, and quantitative targets, etc., andto proceed with analysis/evaluation accordingly.

 Accumulate trial results and verify theirvalidity in order to establish a development
flow of the medium-to-long-term analysis
plan with an analysis project approach
using statistical methods.

 Storage of solid waste according to theprogress of decommissioning work in the future
should be advanced in a safe and reasonable
manner, including temporary outdoor storage ofthe solid waste (except for secondary waste
generated by water treatment and targets ofreuse/recycling) will be eliminated (by FY 2028),
that is stated in the Mid-and-Long-term
Roadmap.

 Examine further possibilities by referring toadvanced cases of overseas, while steadily
continuing approach for volume reduction.

Storage

Processing/disposal The Mid-and-Long-term Roadmap stated thatthe specifications of waste form and theirproduction methods will be determined inPhase 3, the study on appropriate overallmeasures should be initiated for specificmanagement for solid waste.

 Promote volume reduction through incineration,and cutting/crushing, and steadily consolidatestorage inside buildings.

 Create processing/disposal options for solid
waste by examining pending issues related toprocessing technology and disposal options.
 Compare and evaluate options using the property
data that are becoming clear, and examine toestablish a waste stream that is suitable for thecharacteristics of solid waste.

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Holistic Approach for Radioactive Waste Management

Origin: Technical Strategic Plan 2022

Given the prospects of processing/disposal methods and technology related totheir safety presented in FY 2021, appropriate measures should be studied as
management approaches for overall solid waste to establish a waste stream*according to the properties of solid waste.

Procedure to reasonably select safe processing/disposal methods of solid waste

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Analysis and Characterization along the D&D Process

Origin: Technical Strategic Plan 2022

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Enhancement of the Framework of Analysis

Origin: Technical Strategic Plan 2022

Significance and current stateAt present, due to the large range of uncertainty regarding fuel debris properties, safetymeasures should be studied conservatively.



If the range of such uncertainty can be reduced, there is no excessive margins needed,
and thus, rational safety measures can be studied, it enables the promptness andrationality of decommissioning to improve.

Challenges and technical strategies


Since the fine fuel debris generated as
retrieval of fuel debris progresses are diverse
with high radiation dose, it is a challenge toestablish an efficient system for analysis.

It is effective to expand the analysis data under
the appropriate division of roles among thefacilities in the Ibaraki area, where facilities andequipment are enhanced, and the new analyticalfacilities.
It is important to efficiently promote humanresource development with the cooperation ofother institutions.



Characteristics and roles of each facility for analysis

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The Plan of Discharging System for ALPS-Treated Water into the Ocean
Dilute by intaking seawaterfrom outside the harbor

Discharge from the undersea outlet
1 km far from the shore
Via Undersea tunnel

Facilities foranalysis/dilution/discharge

1. Concentrations of radionuclides other than tritium should sufficiently lower thanthe permitted value.
2. Dilute with seawater so that the tritium concentration is less than 1/40th of thepermitted value.
3. Annual tritium in the treated-water should be discharged so as not to exceed theupper limit before the accident.
4. Periodic monitoring of seawater and seafood is required in the surrounding area.
Photo credit： REUTERS, Feb 14,2022 (https://www.reuters.com/world/asia-pacific/japanwelcomes-iaeas-inquiry-into-fukushima-water-release-2022-02-14/)

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Key Issues for Implementing Discharge of Treated Water

Origin: Technical Strategic Plan 2022

Major target
 For the ALPS-treated water currently stored in tanks, measures will be taken for
discharging the treated water about two years after the release of the Basic policy(April 2021)

Challenges and technical strategies
 In addition to “reliably” operate a series of plans including system operation,
analysis of ALPS-treated water, maintenance and response measures in theevent of trouble, TEPCO must review and expand the plans as needed andensure its transparency.
 It is necessary to reassess radiation impacts on human and environment based on the
nuclides to be analyzed, and disseminate the assessment results with high transparency.
 IAEA conducted a safety review on the handling of ALPS-treated water in February 2022.
 The Japanese government plans to commission the JAEA to conduct third-party
analyses before the discharge. The results of these analyses will be disseminateddomestically and internationally with high transparency.
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Position of H-3 in the Toxicity Management

Relative Toxicity (Water Dilution Index)

1.00E+14

Sr-90

1.00E+13

Pu-2391.00E+12
1.00E+11

Pu-240
Am-243Am-241

1.00E+10
1.00E+09
1.00E+08
1.00E+07
1.00E+06

H-3

I-129

Pu-241

1.00E+05
1.00E+04

Cs-137

1.00E+03

Pu-2381.00E+02
1.00E+01
1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

Sr90
Pu238
Am241
Cm244
Pu239
Eu154
Ru106
Am242mSb125
Cd113m
Te125mBa137m
Tc99
H3
I129

Cs137
Pu241
Y90
Pu240
Cs134
Pm147
Am243
Cm243
Ce144
Eu155
Cm242
Sm151
Pr144
Eu152
Sn126

1.00E+06

Years after shutdown
Arranged from JAEA-Data/Code 2012-018 (K. Nishihara et al.)24
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Conclusion-1 The Way Forward
2022

2011
2012 2013 2014 2015 2016 2017 20182019 2020 2021

Environment decontamination

2050
Further strengtheningof infrastructure
Activation of educational humanresources development

Lifting evacuationorders

Activation of Specified
reconstruction andrevitalizationbase

International research education agency

Development of specific reconstruction andrevitalization centers

Development of service infrastructure/return/rebuilding of
livelihoods/others

Creation of industry
including Innovation
Coast Framework

More residents
returning home

Decontaminationof areas other thanspecified reconstruction
and revitalization base

Growing the number ofrelocation and exchange
population

Overcoming decommissioning
mountains through careful
preparation

Future use of
Fukushima Daiichi
site by locals

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Conclusion-2 Trend of Technical Paper Publication
60
50
40

60

D&D and Clean-up
Japan

50

World

40

30

30

20

20

10

10

0

60
50
40

0
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

60

Fuel-Debris
Japan

50

World

40

30

30

20

20

10

10

0

60
50
40

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

60

Radiation Measurement
Japan

0

50

World

40

30

30

20

20

10

10

0

0

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Analyzed with SCOPUS

Remote and Robot
Japan

World

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Radioacitive Waste
Japan

World

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Tritium
Japan

World

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

26
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