Decommissioning of the Fukushima Daiichi NPP
The Holistic Approach of Japan

FDR2019, May 24, 2019
Hajimu Yamana
President, Nuclear Damage Compensation and Decommissioning
Facilitation Corporation (NDF)
Professor Emeritus, Kyoto University©Nuclear Damage Compensation and Decommissioning Facilitation Corporation1

Ground of the decommissioning of the Fukushima Daiichi NPP
Nuclear power generation in Japan• Current capacity: 38 commercial reactors
operational; 38 GWe• Re-started: 8 reactors in power generation• Public’s mood: · Disinclined for nuclear power· Anxiety on radiation safety

D&D of Fukushima Daiichi Reactors

Under construction
Shutdown and decommissioning

Operational
PlannedFukushima Daiichi 1-6

0

10

20

30

60

50

70

Nuclear Power Capacity (GWe)Air Dose Rate as of Nov. 2018
Data by NRA• Successful decommissioning of the fourdamaged units of Fukushima Daiichi is anindispensable prerequisite for Japaneseenergy policy

Fukushima Daiichi
NPP• Eliminating people’s anxiety on the NPP site
is necessary for the revitalization of thesuffered society• Risk reduction of Fukushima Daiichi NPP,
strongly required by regulatory authority

40

80 km radius©Nuclear Damage Compensation and Decommissioning Facilitation Corporation2

Where we are now, and what we are going to do
D&D process for accident nuclear facility generally
understood (IAEA NW-T-2.7)

Radioactive waste management

Emergency
response

Safestore(Optional)

Stabilization

Clean-up

Contaminated watermeasures, ensuringcooling circulation,
rubble removal, spent
fuel removal,
improvement ofworking environment

Mid- and Long-term operations• Spent fuel removal (extended)• Fuel-debris retrieval• Waste storage and treatment• Ground water management(continued)

Demolishing andremediation

Accident
stabilization
Fukushima Urgentof the damaged
Daiichifacilities (Corecooling, highly
D&D

contaminated water
removal, etc.)

Unit-3: March 2011

Demolishing andwaste disposal

Unit-3 SF removal

ALPS

Spent FuelRemovalFuel-debris
Retrieval

WasteManagement

Frozen wall

Tanks for treated water
Pictures from TEPCO

New incinerator©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Organizational structure addressing 1F Decommissioning
Nuclear Emergency Response Headquarters
Government responsibility for disaster response

Whole of related Ministries

NDF as a strategic supporter• Legally authorized organization underjurisdiction of METI and MEXT
• Shareholder of TEPCO by majority of votes

Strategic Proposal

METI
D&D policy(Roadmap)

Compensation facilitation• Loan to TEPCO to facilitate compensation• Business oversight to TEPCO

D&D facilitation

NRA

Oversight• Mid & long tern Technical strategy for D&D• Decommissioning Fund management• Program and Project oversight• R&D strategy and planning• Public outreach

Safety regulation

TEPCO・HD(D&D operation delivery)
As a Licensee
As a Liability holder

Technical contribution

Supervision

IRID/JAEA/University
Technical support through R&D©Nuclear Damage Compensation and Decommissioning Facilitation Corporation4

Responsibility sharing for the 1F Decommissioning
Organizations

Policy and Strategy

Multiple Responsible
Ministries (Gov’t)

Formulation of 1F
D&D Policy(Roadmap: RM)

METI (Gov’t)

Supervision to
TEPCO with RM

Finance

JAEA and IRID

Administrative
directive to TEPCO

Act as a secretariat in
the government

Subsidizing
Universities
Safety Regulation
to TEPCO

NRA (Gov’t)

Tokyo Electric Power
Co. Ltd.

Related works
Individualadministrative actions

Subsidizing
institutes for R&Ds

MEXT (Gov’t)

NDF (semi-Gov’t)

1F D&D Delivery

Development of
D&D Strategy byannual TechnicalStrategic Plan

Reserve Fundmanagement

Development of
implementation
plan

Legally obliged tosecure necessary
fund

Project oversightEngineering
oversight

Coordination of R&Ds
and HRD
Public OutreachInternational Affairs

D&D Delivery as alicense holder

Communication withthe local community

Sample analysis

Execution of R&Ds

METI: Ministry of Economy, Trade and Industry MEXT: Ministry of Education, Culture, Science and Sports NRA: Nuclear Regulatory Authority
NDF: Nuclear Damage Compensation and Decommissioning Facilitation Corporation IRID: International Research Institute for Decommissioning©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Risk reduction strategy

Broadly acceptable area

Data from Strategic Plan 2018 by NDF, 2017
©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Risk reduction as the basic strategy
Snapshot of the existing risk sources

Envisioned risk-reduction trend

Risk level (Sv/unit time)(Inventory of the potential hazard)(A) Crisis level(B) Hastily stabilized with urgent measures(C) Stabilized with strengthened control
Measures against Spent Fuel, Fuel-debris,
Contaminated Water etc.
Acceptable
range of low-risk(Probability of exposure of the hazard)(D) Safe state achieved by D&D(E) Eternally safe stateTime

Data from Strategic Plan 2018 by NDF, 2018

©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Contaminated water is successfully confinedSea-side impermeable wall

Land-side impermeable wall (Frozen soil)

Closed at Oct. 2015

Generation of ALPS-treated waterCs-137 concentration at the south part of the port
Bq/L
10000
10,000Cs-137800000800,000

WHO drinking water guideline

400000400,000

11

200,000
200000
2012

2013

2014

2015

2016

2017

2018

2019

3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月 7月 9月 11月 1月 3月 5月

Source: Modified from TEPCO website.

80000
80,000

Amount

60000
60,000600000600,000

1010

0.10.1
2011

100000100,000

1000000
1,000,000

1000
1,000

100100m3/month

m3

00
14
2014

Rate

40,00040000
20,000
20000

15
2015

16
2016

17
2017

18
2018

©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

00
19
2019

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Large-scale remote operation enabled the SF recovery (Unit-3)
2011

Operatiing floor damaged byhydrogen explosion (appearance)

2015

Removal of large rubbles fallen
down into the poolSep 2011~Nov 2013

Clearing
offfloor
highdamaged
dose rubbles
Operatingby hydrogen
explosion (from the above)

2016

Installation of radiation shielding

Clearing up high dose rubbles

2018

Installation of building cover andremote fuel handling system©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Schedule

Unit-1

Unit-2

Unit-3(Massive rubbles: being removed)(Operating floor: being investigated)(SF removal will start shortly)

Phase-1

Phase-2

Phase-3

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

Unit 1 removal start
Spent fuelUnit 2 removal start
New milestones removal
Unit 3 removalby the revisedstFuel-debris Decision on the method for the 1 unit
Starting from small scale
Mid and LongFuel-debris retrieval for the 1st unit
retrievalterm Roadmap
Waste
Prospect of processing & disposal
management
Pictures: https://photo.tepco.jp/en/index-e.html©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Fuel-debris distributed inside the reactor

Height OP[m]Estimated by severe accident simulation codes,
muon-tomography, and heat balance analysis,
as well as by referring to the result of TMI-2
accident. Inside RPV has yet to be observed.

PCV(g/cc ・m)Muon-tomography result

Distribution of fuel-debris :

Spent
Fuel
Pool

Concretearound PCVCore area

Bottom of PCV

North

South

Horizontal [m]Types of fuel-materials

Data from Strategic Plan 2018 by NDF, 2018
©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Fuel-debris at Fukushima-Daiichi requires more investigation

1F-1,2,3

Fuel-debris of 1F-1,2,3, as its features;
Fuel-debris(U,Zr)Ox, (U,Zr,M)Ox,(Fe, Cr, Ni)x(U, Zr),
(Fe, Cr, Ni)xB, ・・・・・
MCCI product(Zr, U, Ca)O2,
Al-Ca-O
Fe-Si-(Zr,U)-Al• Consists of fuel (UO2, PuO2 and Zircalloy)
and control rods (B4C and stainless steel)• May have reacted with concrete to form
MCCI product• May have reacted with salt coming fromsea water injected during accident• Formed through unclear core disruption
process with complicated dynamics ofthermal and chemical conditions

TMI-2

Chernobyl-4

Refs.: Nagase et. al., J. Nucl. Sci. Mater., Vul. 49, No.1 (2012)

B. Burakov, V.G. Khlopin
Radium Institute, Handout of the 2nd Int. Forum on theDecommissioning of Fukushima Dai-ichi NPS (2017).

©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Fuel-debris retrieval: a daunting challenge
Associated difficulties

Technical Elements Needed⚫ Uncertainty in the property of fuel-debris⚫ Uncertainty in the internal situation⚫ Uncertainty in the behavior of radioactive
materials⚫ Difficult accessibility to the fuel materials⚫ Extremely severe internal environment⚫ Complexity in the water management⚫ Uncertainty in the long-term effect⚫ Internal inspection technique under extreme conditions
inside PCV and RPV
Instrumentation, remote manipulators, robotics,
radiation-resistant electronics, etc.
⚫ New techniques and devices for fuel-debris retrieval
Retrieval machinery for fuel-debris, canister for retrieved
fuel-debris, etc.
⚫ Water management
Processing of contaminated water, groundwater
management, stoppage of leaks in reactor vessels, etc.
⚫ Waste management
Minimization, safe storage, treatment, disposal etc.
⚫ Environmental control
Reduction of atmospheric release, site remediation, etc.
⚫ Safety/Risk assessment and safety control
Risk analysis, safety case, probabilistic analysis, etc.
⚫ Analysis of unknown materials
Characterizing recovered fuel-debris and solid waste,
non-destructive analysis, etc.

©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Fuel-debris retrieval strategy
Careful preparation is necessary for the fuel debris retrieval
１ Ensure confinment
２ Minimize exposure to workers
３ Safe retrieval of fuel debris

Partial-submersion plusside- entry method

Requirements
Seismic integrity

Final selection of the fueldebris retrieval method

Workers safety

Partial-submersion
Lower radiation dose
Side-entry
Confinement ofradioactive materials

SF pool

Confinement andaccess to the debris(Horizontal access)
HEPA
Water
systemGas
treatment

Fuel debris handlingmachineRationales;
Too many penetrations at upper
part of PCV- Technically difficult for water
stoppage- causing too high dose to workers

Prevention of
re-criticality

More information available on
lower part of PCV through recent
remote inspections

Water level control at
PCVs and buildings

Possible to work with SF removal inparallel©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Remote inspection techniques adopted
SA Analysis

Muon measurement

Pictures from IRID

Remote survey

Estimation by MAAP/SAMPSON
ShroudUnit 1
3 Underwater ROV
Unit
Transformer robot

Pellets partially remain
Outer
shell

CR guide tubes
partially remains
Vessel bottom
damagedDeposit of
granular debris

Fuel pins
partiallyremainUnit 1 Underwater view

http://photo.tepco.co.jp/en/indexe.html

2号機 クローラ型ロボット

Photographic images inside the pedestal of Unit-2

Part of FD solidified
not causing MCCI?

Damage of
CR tubeDispersion of
MCCI and FD©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Internal inspection of Unit-2 PCV（Jan. 2018）
CRDs

Data from TEPCO(1) At an upward angle to the lower part of RPV (CRD housings)

CameraPedestal©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Internal inspection of Unit-2 PCV（Jan. 2018）
CRDs

Data from TEPCO(2) At a downward angle in PCV; inside Pedestal

CameraPedestal©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Internal inspection of Unit-2 PCV（Jan. 2018）
CRDs

Data from TEPCO(3) Bottom of PCV; inside Pedestal

CameraPedestal©Nuclear Damage Compensation and Decommissioning Facilitation Corporation18

Newest observation by remote inspection (Unit-2) Data from TEPCO, Feb. 13/2019
Shielding wall Isolation valve

Guide pipe

Telescopic pipe
CRD housing

Biological shield

Remotely operated
observation device

Deposit before touching

Platform

PCV drywell

Pedestal

Deposit being touched

Approaching to bottom

Pictures: tepco.co.jp/decommissioning.information/newsrelease/referemce/pdf/2019/1h/rf_20190213_1.pdf©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Newest observation by remote inspection (Unit-2) Data from TEPCO, Feb. 13/2019©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Planned internal inspection using an advanced remote arm(1) Access to PCV through an existing penetration©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Courtesy of IRID

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Solid waste management approaches
Features of 1F Solid Waste
To date, ca. 400 kt accumulated

Rubbles (metal, concrete)/Woods &leaves/Soils/Incinerables/Adsorbers andsludge from water treatment /Waste
from fuel-debris retrieval operation/
Waste from dismantling Huge volume
 High radiation
 A variety of nuclide compositions and concentration
 Lack of experience in managing and disposing of secondary waste
generated from water treatment in Japan Characterisation needed along with progress of 1F D&D

Increasing storage capacity
for radioactive wastes

New incinerator

Policy for Solid Waste Management
 Focus on characterisation, treatment, packaging and storage until
determination of disposal approach

Today’s Challenges and R&D
 To avoid generation of contaminated waste Volume reduction of solid Waste
 Quick waste characterization
 Determination future disposal method based on provisional wasteform Pursuit of sustainable waste management scheme Reduction of workers dose

New waste storage facility

Storage for rubbles©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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R&D activities for solid waste management
Waste Generation

Ongoing studies along with the lifecycle of the waste

Characterization

Characterization and analysis :• Sampling from stored waste and reactors• Analytical study to characterize wastes and contaminated materials• Correlation study for nuclide composition• Technique to streamline complicated analysis

Safe Storage

Treatment
Solidification

Disposal

Improvement of the storage integrity and efficiency :• Countermeasure for hydrogen generation• Projection of the wastes pertaining to the fuel-debris retrieval operation• Waste segregation by determination of the contamination
Comparative study of solidification technique :• High temperature process
CCIM, In Can Melting, GeoMelt• Low temperature process
Geopolymer, Improved Cement
International survey on disposal :• Disposal concept options• Performance assessment• Experienced regulatory requirements©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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Organizational structure for R&Ds
Core Entities for Decommissioning Implementation
R&D Coordination

METI
Subsidy for
Application R&D

NRA
SafetyRegulation

Strategic
Support to Gov.

Decommissioning
Policy (RM)

NDF

Strategic
Support to Gov.

Subsidy for
Basic Research andHuman Resource Development

Fund Management
Project OversightTEPCO implementation

Contract-based
consigned developments

MEXT

Technical Contribution

Contract-based
implementation

Vendors (Domestic and Foreign)*

JAEA
Research Fund*: A consortium is founded by some Japanese organizations; IRID
(International Research Institute for Nuclear Decommissioning)

Universities

24Conclusions
In line with the holistic approach of Japan, the decommissioning of the Fukushima Daiichi
NPP is progressing. The followings are the highlights.
⚫ The situation of the site has been stabilized to date by adopting various best available
techniques and knowledge.
⚫ Institutional and organizational system to underpin the Fukushima Daiichi
decommissioning has been solidified, and it is working.
⚫ Risk reduction is recognized as the base of the long-term decommissioning challenge,
and the result of the risk assessment shows the strategic direction.
⚫ Difficult spent fuel recovery is progressing by using remote operations.
⚫ Preliminary engineering and developments are ongoing for the fuel-debris retrieval
which will start from sampling and small-scale operation using a remote arm.
⚫ Inspection inside PCV is going forward, giving valuable information to unveil the unclear
status of three units.
⚫ Research and development for the waste management is continuing in line with theprovisional approach.
⚫ Research and development is underpinned by the cooperation of relevant organizations©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

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