Technical Strategic Plan 2023 for Decommissioning of
the Fukushima Daiichi Nuclear Power Station of Tokyo
Electric Power Company Holdings, Inc.

Overview

October 18, 2023

Nuclear Damage Compensation andDecommissioning Facilitation Corporation

Table of Contents
1. Introduction ................................................................................................................................... 3
2. Concept for reducing risks and ensuring safety in the decommissioning of the Fukushima
Daiichi NPS.................................................................................................................................. 5
2.1 Basic policy for the decommissioning of the Fukushima Daiichi NPS ................................... 5
2.2 Concept of reducing risks caused by radioactive materials ................................................... 5
2.3 Approach to ensuring safety during decommissioning .......................................................... 9
3. Technological strategies toward the decommissioning of the Fukushima Daiichi NPS ............ 12
3.1 Fuel debris retrieval .............................................................................................................. 12
3.2 Waste management.............................................................................................................. 23
3.3 Contaminated water and treated water management .......................................................... 27
3.4 Fuel removal from spent fuel pools ...................................................................................... 34
4. Analysis strategy for promoting decommissioning..................................................................... 38
4.1 Significance of analysis on decommissioning ...................................................................... 38
4.2 Current status and strategies for analysis ............................................................................ 39
5. Efforts to facilitate research and development for decommissioning of the Fukushima Daiichi
NPS............................................................................................................................................ 43
5.1 Significance and the current status of research and development ...................................... 43
5.2 Key issues and strategies..................................................................................................... 44
6. Activities to support our technical strategy................................................................................. 46
6.1 Capabilities, organization, and personnel to proceed with decommissioning ..................... 46
6.2 Strengthening international cooperation .............................................................................. 50
6.3 Local community engagement.............................................................................................. 53

2

1. Introduction
The long-term approach to the decommissioning of the Fukushima Daiichi Nuclear Power Stationof Tokyo Electric Power Company Holdings, Inc. (hereinafter referred to as the “Fukushima Daiichi
NPS”) has proceeded under “the Mid-and-Long-term Roadmap towards the Decommissioning ofFukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company Holdings, Inc.”(hereinafter referred to as “Mid-and-Long-term Roadmap”), developed by the Japanese
Government. At present, along with preparations for trial retrieval of fuel debris (e.g., internal
investigation and fuel debris sampling) at the final stage of Phase 21 , efforts toward full-scaledecommissioning work that will begin after the transition to Phase 3－① 2 are steadily being
implemented with the cooperation of the relevant organizations. Fig.1 shows the division of rolesof related organizations responsible for decommissioning.
Nuclear Damage Compensation and Decommissioning Facilitation Corporation (hereinafterreferred to as “NDF”) has supported efforts related to the decommissioning of the Fukushima
Daiichi NPS as an organization that conducts research and development, as well as provides
advice and guidance, required for decommissioning since 2014. This “Technical Strategic Plan for
Decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station” (hereinafter referred toas the “Technical Strategic Plan”), as a part of these supports, has been compiled annually since2015 with the following objectives.
⚫

Providing a solid technical basis for the Mid-and-Long-term Roadmap and contributing to
its smooth and steady implementation, consideration of revisions, and⚫

Providing a basis for “The Policy for Preparation of Withdrawal Plan for Reserve Fund for
Decommissioning”

In addition, since the “Measures for Mid-term Risk Reduction at TEPCO’s Fukushima Daiichi
NPS” (hereinafter referred to as “Target Map for Reducing Risks”) formulated by the Nuclear
Regulation Authority (NRA) takes into account the process specified in the Mid-and-Long-term
Roadmap, the Technical Strategic Plan will also contribute to achieving the goals set forth in theTarget Map for Reducing Risks.

1 Period from the end of Phase 1 to the start of the fuel debris retrieval in the first implementing unit as specified in

the Mid-and-Long-term Roadmap
2 Period from the end of Period 2 to the end of 2031 as specified in the Mid-and-Long-term Roadmap3

Nuclear Emergency Response Headquarters (Director: Prime Minister)
Nuclear Regulation Authority➢ Decide the direction of decommissioning and contaminated water
treatment➢ Approval of implementation plan,
pre-service inspection, welding
inspection, etc.
➢ Providing goals for risk reduction(Chairperson: Chief Cabinet Secretary)

Mid-and-Long-Term Roadmap

The Team for Countermeasures for Decommissioning
and Contaminated Water Treatment(Head of Team: Minister of Economy, Trade and Industry)➢ Progress management of each countermeasure according toMid-and-Long-Term Roadmap

Apply forapproval

Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Granting of
project budget➢ Development of a mid-to-long-term strategy

Withdrawal plan

➢ Management of Reserve Fund for
Decommissioning

Share progressand challenges

Reserve Fund for
Decommissioning

Advice, guidance, recommendations,supervision and support
Reserverelated to project management, etc.

ReportDisburse-ment

Apply for report

Technical ➢ Tech. support for progress management of important
issues (in collaboration)
Strategic ➢ R&D planning and progress management
plan ➢ Strengthen international partnership

R&D organization
Japan Atomic Energy Agency (JAEA),etc.
➢ R&D implementation

Approve

Monitoring, examination

Progressmanagement

Target map for Reducing
Medium-term Risk

Minister of Economy, Trade and Industry
Presentation ofimportant issues

ReportReport on theoutcomeReportBidirectional dialogue

Local residents and communities

Organizations related to decommissioning

Council for the Decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station*

Tokyo Electric Power Company Holdings, Inc. (Fukushima Daiichi Decontamination and Decommissioning Engineering Company)➢ Contaminated water and ALPS-treated water management, fuel removal from SFP, fuel debris retrieval, waste management, etc.
➢ Through TEPCO's management reform, the funds required for decommissioning should be reserved
responsibly (Implementation of the 4th special business plan)Mid-and-Long-term➢ Detailed measures for facility safety and protection of nuclear fuel material
Decommissioning Action Plan
(Development of implementation plan for specified nuclear facility)* In response to the ALPS-treated water disposal policy decided on April 13, 2021, “Council for the Decommissioning of TTEPCO’s Fukushima Daiichi NPS toward steady implementation of basic policy on ALPS-treatedwater disposal” was founded.

Fig. 1 Division of roles of related organizations responsible for decommissioning of the
Fukushima Daiichi NPS

4

2. Concept for reducing risks and ensuring safety
decommissioning of the Fukushima Daiichi NPS

in

the

2.1 Basic policy for the decommissioning of the Fukushima Daiichi NPS
The basic policy for decommissioning the Fukushima Daiichi NPS is “to continuously and quickly
reduce the risks arising from the radioactive materials caused by the accident that do not exist in
normal nuclear power plants.” In addition, ensuring the safety of decommissioning work requires
measures from a long-term and comprehensive perspective on the balance of risks based on safetycharacteristics. It is also important to consider flexible risk reduction strategies.
Regarding fuel debris retrieval, in Phase 3-[1] preparations for further expansion of fuel debris
retrieval in scale, which will be full-scale decommissioning work, will be promoted. Though thecurrent state of temperature and pressure inside the Primary Containment Vessels (hereafterreferred to as PCVs) is stable, conditions will change with the start of fuel debris retrieval. Thus, it
is undeniable that risks previously perceived as minor or unknown may become apparent. To
effectively respond to risks toward further expansion of fuel debris retrieval in scale, the issue is toimprove the ability to observe conditions inside the PCVs where changes in these risks are most
likely to occur. Therefore, consideration should be given to expanding the type and number ofmonitoring targets, while taking into account the current purpose of the monitoring parameters andthe number of monitoring devices in the PCVs and difficulties in on-site operation.

2.2 Concept of reducing risks caused by radioactive materials
2.2.1 Quantitative identification of risks
The Technical Strategic Plan uses a method

Region of sufficiently
stable management

Detriment

score

(SED)

to

express

Hazard Potential (logarithmic scale)based on the Safety and Environmental
themagnitude of risk (risk level) posed byradioactive materials. In this method, the risk
level is expressed by the product of “Hazard
Potential”, an index of the impact of internal
exposure by intake of radioactive materials into
the human body, and “Likelihood of Occurrig3”,
an index of the likelihood of an event occurring.

(March 2023)

Fuels incommonpool

Fuel debris

Contaminatedstructures in bldgs.

Unit 1
ALPS Unit 3
slurryUnit 2

Fuels indry casks

Rubble instoragefacility

Waste
absorption
Fuels incolumns Waste Unit 2
SFPs
sludgeUnit
1Concentrated
ALPS
liquid waste,slurryetc. (to be transferred to other HICs)
Stagnant water inbuildings
Zeolitesandbags
Stored waterin welded tanks Residual waterin flanged tanks
Soil covered
temporarystorage, etc.
Outdoorstorage, etc.

The current risk levels assigned to theRequiring Level for Safety Management(logarithmic scale)respective risk sources are expressed in Fig. 2

Fig. 2 Risk levels posed by major risk sourcesat the Fukushima Daiichi NPS
3 This "Likelihood of Occurring" was named "Safety Management" until the Technical Strategic Plan 2022, thename has been reviewed in the Technical Strategic Plan 2023, but the definition has not been changed. This
review was undertaken to explicitly indicate that higher levels of safety management measures are required
when the integrity, packaging and monitoring conditions of the facilities containing the risk source areinsufficient, or when the risk source itself is highly reactive.

5

with “Hazard Potential” and “Requiring Level for Safety Management” as the axes. The parts in red
represent risk sources that have changed significantly from the Technical Strategic Plan 2022
(assessed as of March 2022), and the starting points of the arrows indicate the location in TechnicalStrategic Plan 2022.
ALPS slurry (to be transferred to other HICs) was moving downward because Hazard Potentialof shifted ALPS slurry (green) has decreased as the progress of the transfer operation. Note that
there is little variation in the ALPS slurry (green) on a logarithmic scale, since the shifted percentageof the Hazard Potential of ALPS slurry (green) to the original ALPS slurry (green) is small. For the“contaminated structure in buildings”, Requiring Level for Safety Management increased, reflecting
the retaining hydrogen that flowed into the system connected to the PCV at the accident.
2.2.2 Risk reduction strategy
2.2.2.1 Interim targets of the risk reduction strategy
Measures for risk reduction include the reduction of the “Hazard Potential” and the reduction of
the “Requiring Level for Safety Management”, reduction of the “Requiring Level for Safety
Management” is generally considered to be easily realized from an engineering perspective. The
immediate goal, therefore, is to reduce Requiring Level for Safety Management by the methods
described above and bring it into a “sufficiently stable management” region (Fig. 2) that is equal toor lower than the level of facilities that are not affected by the accident or facilities that were
designed after the accident to allow for a long-term storage. The process to bring it into a“sufficiently stable management” region and the progress of decommissioning work in line with thatprocess are shown in Fig. 3. “Requiring Level for Safety Management” can be expressed as the
product of two factors: one pertaining to the sufficiency of the containment function of the facility
that contains the risk sources (hereinafter referred to as “containment performance”), and the otherpertaining to the long-term stability and handleability of the risk source, such as its characteristics(degradation and activity level), packing, and monitoring conditions. As this method to reduce thelikelihood of an event expressed in “Requiring Level for Safety Management”, the first is to improvethe containment performance of the facilities that contain risk sources. Measures to improve thecontainment performance include transferring the risk sources to more sound facilities on higher
ground that are less susceptible to tsunamis, as well as repairing damaged parts of existing storage
facilities caused by external factors. The second is to improve the long-term stability by reducing
uncertainty in handling risk sources and by enabling long-term and stable management based on
the characteristics of risk sources. To this end, it is important to obtain sufficient information by
investigating the distribution of risk sources, identifying their characterization through analysis andmeasurement, and improving monitoring conditions, and to reflect this information appropriately inmethods of collection and storage according to the characteristics of risk sources. Such efforts to
reduce uncertainty in the handling of risk sources also help to keep the temporary increase in risk
levels associated with risk reduction measures, such as risk source recovery operation, to a low
level.

6

Fig. 4 shows the transition of Requiring Level for Safety Management corresponding to risk
sources and their treatment process indicated in the flow graphically by risk source category. The
Requiring Level for Safety Management shown is divided into two components, one for containment
performance and the other for long-term stability, which correspond to the methods for reducing
the Requiring Level for Safety Management described above. This will help determine whether
containment performance or long-term stability measures should be prioritized to bring the risk
source into the “Sufficiently stable management” region. In addition, in the processing process thatis the scope of a future or ongoing study in the flow, the blue and orange arrows in Fig. 6 (d) indicate
what needs to be improved to bring the level of Requiring Level for Safety Management into the
Sufficiently Stable Management region (in the pale blue area in the graphs).
Specific risk reduction strategies for each source are detailed in Chapter 3.

Arrows show the shifting/processing flow of risk sources.
Dotted lines indicate the scope of future studies and being studied.
Category

Sufficiently stable
management condition

Processing

Risk source

Reducing risks by processing

Fuel debris

Fuel debris inside
PCV

Retrieve

Temporary storage
for fuel debris

Storage for fuel debris

Spent fuelSpent fuel pool

RemoveCommon Spent
Fuel Storage PoolDry cask

Cs-137
released during
the accident

Stagnant water inbuildings

Purify Cs/Sr

Stored water inwelded tanks(Sr-treated water)

Removemultinuclide

Water
filtering*１※2

Residual water inflanged tanks

Filtered water

Stored water inwelded tanks(ALPS-treated water)

Sludge*2Concentrateby evaporation(Operation stopped)*１

Concentrated liquid
waste, etc.
ALPS slurry(Incl. ALPS slurry to be（高線量HIC含む）
transferred
to other HICs)

Dehydrate/stabilize

Solid waste
storage facility

Temporary storageof used columns(Sorption columns)

Decontaminate(Operation stopped)

Waste sludge
Collect/stabilize
Zeolite sandbags

Contaminatedstructures in bldgs

Dismantle/
RemoveOutdoor storage, etc.

Reducevolume, etc.

Rubbles, Felled trees, etc.

*１ Connect the arrow from
“Remove multi-nuclide”*２ Connect the arrow from
“Water filtering”

Soil-covered, etc.

Discharge into theenvironment

Fig. 3 Risk reduction process for major risk sources and the progress (as of March 2023)

7

Legend<Likelihood of Occurring>
Requiring Level for Safety Management(logarithmic value)

Components of Requiring Level for Safety Management
pertaining to containment
Components of Requiring Level for Safety Management
pertaining to long-term stability

Criticality control

Sufficiently stable management region
Lower limit of Requiring Level for Safety Management (calculated
from the lower limit of the component pertaining to containment
and the lower limit of the component pertaining to long-term
stability

Retrieval

Lower limit of the component pertaining to containment<Treatment process>
Treatment in progress*The Requiring Level for Safety
Management of ④ is assumed value atthis time and may change dependingon the progress of future studies, etc.

Treatment needed in the future (improvement of containment
performance)
Treatment needed in the future (ensuring long-term stability)(a) Fuel debris

Multi-nuclides

Requiring Level for Safety Management(logarithmic value)

Sludge (transferred to Solid waste storage)

Cs/Sr-treatment
Cs adsorbed(logarithmic value)

Requiring Level for Safety Management

Filtered water

Accumulated absorbed
dose of HIC exceeded

Change of HIC needed(slurry transferred toother HIC)

removalTransferred to solid
waste storage*The Requiring Level for Safety Management of ⑥
is assumed value at this time and may change
depending on the progress of future studies. etc.
Requiring Level for Safety Management* Treatment of secondary waste generated by water treatment ③, ④, and ⑦ is shown in (c).
© の処理はStabilized(c) Secondary waste generated bywater treatmentに表示(b) Contaminated water

Fig. 4 Changes in Requiring Level for Safety Management for major risk sources
2.2.2.2 Basic approach to risk reduction
There are still significant uncertainties in decommissioning the Fukushima Daiichi NPS.
Eliminating these uncertainties requires many resources and, in particular, a considerable amountof time. However, to realize prompt risk reduction, it is necessary to promote the decommissioning
work while ensuring safety as the top priority by making comprehensive decisions based on theknowledge obtained, even though uncertainties remain to a certain extent. Regarding theperspective from which these comprehensive decisions will be made, NDF summarizes thefollowing five guiding principles:(Five guiding principles)➢ SafeReduce the risks posed by radioactive materials and ensure
work safety➢ Proven
Use highly reliable and flexible technologies➢ Efficient
Use resources effectively (e.g., people, things, money andspace)➢ Timely
Be conscious of time
➢ Field-oriented Comprehensive three-realities policy by checking actual site,actual things, and actual situation

8

In applying the five guiding principles to the actual site, it is important to proceed with thedecommissioning operation after greatly emphasizing safety assurance for the purpose ofprotecting human beings and the environment from the radioactive materials associated with theoperations, thoroughly conducting radiological impact evaluations, and taking appropriate
radioprotective measures (Safe).
In the decommissioning of the Fukushima Daiichi NPS, because the public risk level is rising withtime as the degradation of facilities damaged by the accident progresses, controlling this risk to be
as low as reasonably achievable (Proven, Efficient) as promptly as possible (Timely) in light of thesituation at the site, and proceeding with the decommissioning in a reliable manner by feasible
ways in the harshest on-site state (“Field-oriented”) will lead to ensuring safety in the medium-tolong-term.
As for the result judged based on these guiding principles, it is also important to work todisseminate information carefully so that the results will be widely accepted by society.

2.3 Approach to ensuring safety during decommissioning
2.3.1 Basic policy for ensuring safety based on the characteristics of Fukushima Daiichi
NPS
The decommissioning of the Fukushima Daiichi NPS that contains the reactors involved in theaccident is an unprecedented activity taking place in a peculiar environment different from that ofa normal reactor, and therefore, to ensure safety, the issue is to sufficiently consider the following
characteristics (peculiarities) regarding safety:⚫

A large amount of radioactive material (including α-nuclides that have a significant impact
on internal exposure) is in an unsealed state, as well as in unusual (atypical) and various
forms.

⚫

Barriers for containing radioactive materials, such as reactor buildings and PCVs, areincomplete.

⚫

Significant uncertainties exist regarding the state of these radioactive materials andcontainment barriers, etc.

⚫

It is difficult to access the site and install instrumentation devices to obtain on-site
information due to constraints such as high radiation levels on site.

⚫

Since the current level of radiation is high and further degradation of containment barriers
is a concern, it is necessary to take measures in consideration of the time axis without
prolonging the decommissioning activities.

Therefore, in proceeding with decommissioning work, TEPCO, as the decommissioning project
executor, needs to consider the following points with particular attention, based on the five guiding
principles.

9

First, with regard to "safe", for the above peculiarities, it is necessary to assume a wide rangeof possibilities (cases) and to check that it is possible to ensure safety for them as the starting point
for all considerations. At the same time, it is important not to prolong the work period considering
the risks over the entire work period, and it is necessary to avoid excessive safety measures out of
proportion to the risks and to take sensible safety measures (ALARP). It is important that thisperspective on “safety” (the safety perspective) is reflected in the consideration of decommissioning
work.
Second, with regard to “field-oriented”, it is essential to reflect the information obtained from theactual site in engineering appropriately, because there is a limit to the response by design alone
due to large uncertainties. In order to reliably implement unprecedented engineering such as fueldebris retrieval, it is important to value the viewpoints and senses of people and organizations who
are directly involved in the actual site work and familiar with the site, and to respect the viewpoints
and judgments that are directly addressed at the site (the operator’s perspective). Moreover, in
promoting long-term decommissioning, it is necessary to maintain and strengthen the operator's
viewpoint and sensibility, TEPCO itself should take over the operator's perspective.
In the actual study of the decommissioning work, TEPCO, as the decommissioning project
executor, should define the “requirements” to satisfy regulatory demands for the work, and should
consider specific safety measures to achieve them. In doing so, it is essential to apply the safety
perspective and the operator’s perspective to handling the characteristics (peculiarities) of
decommissioning the Fukushima Daiichi NPS.
In this decommissioning work with significant uncertainties, it is frequently difficult to uniquely
define requirements and the equipment/operational specifications that will satisfy thoserequirements. Even in such cases, the decommissioning work should be carried out flexibly andpromptly by verifying and improving the selected, specifical safety measures with the “preliminary
implementation and utilization of the obtained information in the latter stages” and “iteration-based4
engineering”.
2.3.2 Preliminary implementation and utilization of the obtained information in the latter
stage
Because of the high uncertainty surrounding the Fukushima Daiichi NPS, it is necessary toassume extremely large safety margins and a wide range of technological options. In addition,
considering the further deterioration of containment barriers and other factors, it is necessary to
immediately improve the state of risks and reduce uncertainties. Therefore, a “sequential typeapproach” is important, where “operation at first stage” is implemented for which, practical safety
can be ensured, and then the information obtained there is utilized in the next stage, gradually
reducing uncertainty in the entire decommissioning process.

4 A method of gradually increasing the level of completion of engineering by finding the next result based on acertain result and repeating this cycle.

10The decommissioning of the Fukushima Daiichi NPS needs to be promoted with the broad
understanding of not only the government, NDF, TEPCO, and others, but also of a wide range of
people, including local residents. To this end, it is essential for them to fully understand the overallrisk reduction efforts described in this chapter and to gain their understanding of thedecommissioning project. In particular, it is important to establish a system for continuous risk
monitoring that is easy to understand for a wide range of people and to communicate to the public
how the decommissioning work will be conducted based on the risk reduction strategy, how thesafety of the decommissioning work will be ensured, and how the overall risk reduction of the site
is continuously progressing through the decommissioning work, and to disseminate theseinformation to society.
In addition to sharing the status of risks regard to the decommissioning of the Fukushima Daiichi
NPS through the Technical Strategic Plan on a constant basis, NDF is considering providing therisk reduction process along with the progress of the decommissioning work. TEPCO also needs
to develop a mechanism to identify risks for the entire site and become aware of the need to takeaction to communicate the status of risk reduction to society in a proactive manner.

11

3. Technological strategies toward the decommissioning of the
Fukushima Daiichi NPS
3.1 Fuel debris retrieval
3.1.1 Target⚫

Retrieve fuel debris safely after thorough and careful preparations, and bring it to a state ofstable storage that is fully managed.

⚫

The trial retrieval process in Unit 2 is under review to improve work safety and reliability during
retrieval, and trial retrieval will begin in late FY 2023. Continue the series of operations, including
the gradual expansion of fuel debris retrieval, to acquire the knowledge and experience
necessary for further expansion of fuel debris retrieval in scale.

⚫

With regard to the further expansion of fuel debris retrieval in scale, consideration will be given
to the methods including those for containing, transferring, and storing of fuel debris, throughthe assessment of fuel debris retrieval in Unit 2, internal investigations, research anddevelopment, and the on-site environmental improvement, etc.

3.1.2 Progress⚫

Unit 1：In the PCV internal investigation, detailed visual observation, deposit thickness
measurement, deposit debris detection and evaluation, and deposit 3D mapping
measurement were conducted outside the pedestal from February 2022. In March
2023, using a submersible boat-type access investigation vehicle (submersible
ROV), survey inside the pedestal was successfully conducted for the first time. As
a result of the series of investigations, a lot of information was obtained such as
the distribution status of the deposit outside the pedestal, the neutron flux level, thecondition of the deposit and fallen objects at the inner bottom of the pedestal, andthe condition of the upper structures such as the control rod drive (CRD) housings.
Deposit sampling was also successful, and analysis will be performed in the future.
Because the vicinity of the pedestal opening (worker access opening) and almost
the entire inner wall of the pedestal have lost their lower concrete, TEPCO isevaluating the impact of external exposure, supposing support function of thereactor pressure vessel (hereinafter referred to as “RPV”) on the pedestal
deteriorates to form a large opening in the PCV. As a result of evaluating conditions
inside the PCV by setting conservative conditions, TEPCO considers that there isno significant risk of radiation exposure, however, further safety measures such as
mobile response and enhancement of PCV containment function are being
considered. These evaluations by TEPCO were approved at the NRA Committee.

⚫

Unit 2：Modification and verification of the control software for the robot arm to be used
for trial retrieval and improvement of some devices were implemented, andconfirmation of the required functions is in progress. As on-site preparatory work,
installation of the isolation chamber was completed in April 2023. Currently,
removing the flange bolt, opening the hatch of the penetration X-6, and removing
the deposits inside the penetration are in progress.

12⚫

Unit 3：The method for further expansion of fuel debris retrieval in scale is being studied.
In FY 2023, evaluation including business continuity is underway, with continued
issue studies of each method. In addition, since February 2023, the SubCommittee for the Evaluation of Fuel Debris Retrieval Methods has been
established under the Decommissioning Strategy Committee, a committee of
NDF, technical feasibility and business continuity in each of fuel debris retrieval
method are being studied and evaluated technically and intensively.

3.1.3 Key issues and technical strategies
3.1.3.1 Fuel debris retrieval strategies in each Unit⚫

Common : There are many areas where direct visual information is not available for each Unit,
and it is a challenge to promote further internal investigation and obtain various
kinds of information. Work will be carried out by formulating/updating the future planfor internal investigation, assuming further expansion of fuel debris retrieval in scale.
The direction of the fuel debris retrieval strategy should be ascertained on the basisof the acquired information in order to avoid engineering backsliding and to increase
the reliability of the method chosen.

⚫

Common : Regarding field problems experienced so far, measures for preventing recurrence
should be reflected in the next work. In addition, methods that can eliminate
assumed risks should be developed, and if the risks cannot be eliminated,countermeasures should be prepared in advance.

⚫

Common : With a view to business continuity, methods that enable retrieval even if all on-site
conditions cannot be identified, and other methods (robust methods) not easily
affected by external events such as earthquakes should be examined while taking
into account on-site conditions such as damage to facilities and equipment⚫

Common : Efforts should be made to prevent the concentration of worker radiation exposure
on specific individuals, reduce the exposure of all workers, and secure humanresources from a long-term perspective.

⚫

Unit 1: Toward further expansion of fuel debris retrieval in scale, studies on retrieval
methods will be promoted by taking into account the on-site information and theknowledge gained so far and to be gained in the future, such as from the trial
retrieval from Unit 2, the gradual expansion of fuel debris retrieval, research anddevelopment, the engineering for applying the R&D results on-site, and the resultsof the PCV/RPV internal investigation.

⚫

Unit 2: Trial retrieval will be promoted to lead to a gradual expansion of fuel debris retrieval.

⚫

Unit 3: Considering that the removal of fuel in SFP has been completed and there is little
interference with other operations, and working environment of the reactor building
will be improved faster than Unit 1, retrieval methods are being examined for further
expansion of fuel debris retrieval in scale ahead of other Units.

3.1.3.2 Trial retrieval (internal investigation and fuel debris sampling)
The trial retrieval, which is under preparation at Unit 2, is intended to access the inside of thepedestal from outside the PCV for further internal investigations and collect small amount of fueldebris. This is because the effort is of great significance, entering a new phase, in whichcontainment barrier outside the PCV is extended by opening the hatch of the existing penetration
X-6 on the PCV, a series of work tasks should be implemented in a phased manner. (Fig. 5). The
information obtained from this efforts will be used for subsequent gradual expansion of fuel debris

13retrieval and further expansion of fuel debris retrieval in scale. In addition, since this will be the first
fuel debris retrieval at the Fukushima Daiichi NPS, the experience gained during the process fromthe examination to the retrieval operation and the information obtained through the analysis of theretrieved samples will be used in future decommissioning efforts.
It is necessary to proceed with the work safely and carefully, assuming the possibility that thework may not go as planned due to the uncertainty of the conditions inside the PCV. It is important
to utilize the valuable information, experience, etc., gained through them in subsequent retrieval
operations including for other Units.
Given the adhering condition of the bolts confirmed in the ongoing work to open the penetration
X-6 hatch, etc., difficulty in deposits removal may be also a concern inside the penetration X-6, so
it is necessary to study in advance a method that enables fuel debris retrieval even if the deposits
inside the penetration cannot be completely removed. TEPCO is also considering the use of atelescopic device that has been used in past investigations and confirmed to be accessible to thebottom of the pedestal as a method to complement the internal investigation and trial retrieval by
the robot arm.
(1) Preparatory work (completed)
Cutting machine (hole saw)

●Prework for spray jig installation(Hole diameter enlargement of thepenetration X-53)(6) Robot arm entry(7) Internal investigation and fuel debris sampling① Internal investigation by robot arm(2) Installation of an isolation chamber (completed)●Isolation chamber
installed prior to opening
hatch⚫ Remove obstacles (CRD rail,
conduit) with【AWJ】at theend of the arm②Fuel debris sampling by robot arm
Tip of fuel debris retrieval device(3) Opening of the penetration X-6 (in progress)<Wire brush type>

Hatch releasing apparatus●Opening of the hatchof penetration X-6 byhatch opener<Vacuum vessel type>(Note) - Isolation valve : Valve installed to separate inside/outside of PCV- AWJ (Abrasive Water Jet) : Processing machine that mixes abrasives with high-pressure
water to improve cutting performance(8) Storage to shipping containers from fuel debris retrieval equipment,
and dose measurement(4) Removal of deposits in the penetration X-6(9) Acceptance into glovebox and measurement

Remove deposits and cables in the penetration X-6⚫ 【Low/High pressure
water】to push deposits●Accept into a glovebox
with negative pressure
inside●Weighing and storing incontainers in a glovebox

Law/high pressure water
Penetration X-6
Entrance side

Deposits⚫ 【AWJ】to remove cable
Glovebox
Push-in device<Appearance of a glovebox>

Cable removal with AWJ⚫ 【Push-in device】
to push-in cables(10) Removal of containers, storage in shipping containers, and carry-out●Remove the container with a plastic bag to prevent
contamination from spreading●Stored in off-site transport cask and loaded ontotransport vehicles(5) Robot arm installation
Isolationvalve

Off-site transport cask ＊Plastic bag

Robot arm

Transport to transport vehicles*: Measure the surface dose and contamination density of the transported materials prior totransport and confirm that they are below the legal standard value(11) Off-site transport/off-site analysis (analysis of fuel debris properties)(TEPCO material edited by NDF)

⚫ The analysis results will be used for subsequent gradual expansion of fuel debris retrieval and further
expansion of retrieval in scale.

Fig. 5 Work steps of trial retrieval (internal investigations and fuel debris sampling)14

3.1.3.3 Gradual expansion of fuel debris retrieval
The gradual expansion of fuel debris retrieval is being prepared in Unit 2 for the period until
further expansion of fuel debris retrieval in scale begins. Its main objectives are to verify the retrieval
equipment, acquire data on the environmental impact during the retrieval operation, increase theamount of retrieval, obtain data on fuel debris composition and properties from more samples, andaccumulate the retrieval experience of workers.
(1) Retrieval equipment
The retrieval equipment to be used for the gradual expansion of fuel debris retrieval will be
improved by increasing the payload and enhancing accessibility, based on the improvements
identified during the verification phase of the equipment for trial retrieval. The plan is to expand
the range of retrieval while making achievements, starting with retrieval of fuel debris that can be
gripped and sucked, and expanding to fuel debris retrieval with cutting. Consideration will also
be given to the possibility of cutting platform beams and the range of cutting.
Shielding and preventing the spread of contamination are considered for the enclosure
containing the robot arm to take in fuel debris. In addition, because the manipulator to be installedin the enclosure performs various operations and maintenance, it is necessary to ensure therepeatability of tasks and train operators. Moreover, the work period is in the order of several
years. Thus, in addition to periodic maintenance, preparation in case of failure is a challenge.
Since the radiation dose in the reactor building, where the enclosure will be installed, is high andit is difficult to perform maintenance there. Therefore, the plan is to construct a maintenancebuilding outside the reactor building and equipment and enclosures will be transferred there, thendecontamination, dismantling, repair, or replacement will be conducted inside it. The issue is toleverage the experience gained through the maintenance of equipment/devices for further
expansion of fuel debris retrieval in scale. Therefore, a system that can reliably preserve
maintenance records, including failure histories and corresponding measures, should beestablished. NDF will continue to grasp and check the status regarding the technologicaldevelopment of retrieval equipment and preparation for field application as needed from theviewpoints of safety assurance and the actual site applicability.
(2) The first storage facility
As to the first storage facility5, during their designing, there are many points of contact withrelated facilities such as receiving fuel debris and sending samples for analysis, and when they
are installed, there are a lot of interfacing and contacts between various types of work andoperation including peripheral work. Therefore, project management by TEPCO is essential forprocess control and resolution of pending issues. Leveraging the experience and knowledge
5 As the study progressed, the name was changed because TEPCO decided to store retrieved fuel debris atstorage facilities instead of temporarily storing it in temporary storage facilities.

15

gained from this design and installation work for future projects and construction management is
expected. Various remote-control devices are also used for handling fuel debris in the firststorage facility. It is necessary to refer to the knowledge related to other remote-control devices
and incorporate countermeasures to mitigate potential risks at the design stage into the design.
3.1.3.4 Further expansion of fuel debris retrieval in scale
Further expansion of fuel debris retrieval in scale is an important process in decommissioning,
and its reliable implementation will determine the success or failure of the decommissioning project.
In light of this, it is necessary to discuss methods with a view to business continuity. Moreover, theFukushima Daiichi NPS has a unique environment different from a conventional reactor, which
requires understanding the following factors that make fuel debris retrieval difficult:① Extremely high-radiation dose in PCVs
and RPVs④ Building containment barriers⑤ Criticality control② High-radiation dose in reactor buildings⑥ Waste management③ Lack of on-site information

Therefore, the following should be considered when proceeding with examining methods.
⚫

Given an unusual environment different from normal reactors, it is important to consider
retrieval method with appropriate requirements for ensuring safety.

⚫

On-site information such as the location, quantity and properties of fuel debris is important toinvestigate the method, and a comprehensive analysis and evaluation is conducted toestimate the information necessary for the method study, based on previous internal
investigations, analytical evaluations, and past finding. Such efforts should be continued in
the future, and the accuracy of method investigations should be improved by reflecting the
new results obtained through internal investigations, etc., in information for the method study
as appropriate.

⚫

When examining retrieval methods, after reviewing the several paths, it is important to
combine and narrow down these paths to take according to the on-site information such as
internal investigations obtained afterward and the progress of technical studies. In
considering several paths, it is necessary to control potential risks in each process frompreparatory work to the completion of fuel debris retrieval, and it is also necessary to develop
fuel debris retrieval scenario while constantly checking the risk level and risk measures.

⚫

As the scale of work, devices, and facilities will increase and the area of construction will
expand, examination should be carried out by setting the requirements (site use area,interfacing with existing systems, groundwater management, waste management, etc.) moreclearly in light of the entire power plant, in addition to the requirements for retrieval methods.

⚫

For each task in the work sequence, issues that may significantly affect technologicalfeasibility should be comprehensively identified in order to prevent the issues from being

16

overlooked. It is necessary to verify that the issues identified can be addressed from theperspective of actual site applicability and technological feasibility.
⚫

In evaluating methods, based on the five guiding principles (safe, proven, efficient, timely, andfield-oriented), in addition to the assessment of checking the actual site applicability andtechnological feasibility, assessment on business continuity also needs to be used as thedecision indexes. The criteria to be used in the evaluation should also be clarified from theinitial stage of studying the methods.

At present, the conceptual study on the further expansion of fuel debris retrieval in scale for Unit
3 is in progress. Many challenging issues have been identified with respect to methods proposedfor discussion by the end of FY 2021. As a result, in FY 2022, the actual site applicability andtechnical feasibility associated with measures for mitigating these issues were verified. In FY 2023,
evaluation including business continuity will be promoted, with continued issue studies of eachmethod. In addition, preparatory works such as yard development, which will be necessary
regardless of the retrieval method, are also being identified and organized to specify them as soon
as possible. Selecting a specific method is an extremely important decision to determine thesuccess or failure of decommissioning over the medium to long term. Thus, not only TEPCO but
also the national government and NDF must cooperate to comprehensively examine and evaluate
technological feasibility, with safety as a major prerequisite. To this end, in February 2023, the SubCommittee for the Evaluation of Fuel Debris Retrieval Methods was established under theDecommissioning Strategy Committee, a committee of the NDF, to conduct technical and intensive
study and evaluation on the technical feasibility and business continuity for each method of fueldebris retrieval. The following is an overview of the Partial submersion method (water injection into
RPV) (Fig. 6(a-1)), the Partial submersion method option (RPV filling and solidification) (Fig. 6(a2)) and the Submersion method (shell structure) (Fig. 6 (b)), and their issues. The outline of eachmethod is only an example and is not definitive.

17

Access direction of the devices
Transfer direction of fuel debris and radioactive waste
Filler material(a-1) Partial submersion method (a-2) Partial submersion method option(RPV filling and solidification)(water injection into RPV)(b) Submersion method(shell structure)

Fig. 6 An example of each retrieval method for further expansion of fuel debris retrieval in scale(1) -1 Proposed Partial submersion method (water injection to RPV)
The partial submersion method (water injection to RPV) is a method for retrieving debris
exposed in the air or immersed at a low water level while pouring water. The main method ofaccess to fuel debris inside the RPV and in the pedestal will be from the top (top-access), while
fuel debris outside the pedestal will be accessed from the side (side access). The issues andcountermeasures of this method are summarized below according to the aforementioned factors① to ⑥.
⚫

Factor ①
Extremely highradiation dose in
PCVs and RPVs

: Some of the work in the buildings can be implemented manually, but in
High-radiation dose such cases, the issues are careful exposure control as well as
in reactor buildings
environmental improvement. When it is difficult to reduce the radiationdose, operations using remote control devices will be necessary, and thesame measures will be required as with factor ①.

⚫

Factor ②⚫

Factor ③
Insufficient on-site
information⚫

: The issue is that all operation inside the PCV/RPV will be conducted using
remote control devices. After identifying the required operations including
what is expected to be done, the function, structure, and general safety
requirements of the remote control device should be established.

Factor ④: The issue is that the retrieval method must be considered based on theuncertainty of on-site information due to the limited results of the on-site
survey. Therefore, in addition to obtaining on-site information throughinternal investigations, remote control devices and work procedures should
be considered to allow for flexible response in cases where the on-sitesituation still cannot be identified.
: The issues are seismic feasibility of the top access platform andBuilding containment airtightness of interface with existing structures. As a countermeasure, it isbarriers
necessary to assess the validity of seismic conditions as well as study

measures for reducing the upper load and examination of structure toensure airtightness. In addition, because existing structures are used as
containment barriers facilities, the issue is to examine airtightness andseismic resistance in consideration of the fact that they are damaged by
the accident and the aging deterioration. In view of long-term use in the
future, it is necessary to monitor, investigate, and assess damage,deterioration, and corrosion conditions, and by taking these into account,18

it is also necessary to continuously check the earthquake resistance andstructural integrity.
⚫

Factor ⑤
Criticality control⚫

Factor ⑥: The issue is to have criticality control take shape appropriately for the onsite conditions. Design measures to be considered include the use ofmultiple monitoring means, setting limits on cutting operations, andinstalling systems capable of injecting neutron absorbers. Meanwhile, as
operational measures, the amount of state change is assessed, and whena condition approaching criticality is detected, criticality is prevented bystopping operations, adding neutron absorbers, and determining whether
operations can be resumed.
: The issue is handling a large amount of waste, such as dismantled
buildings and excavated soil in areas that interfere with new structure
construction. A plant-wide waste storage plan should be developed toverify that the waste to be generated can all be stored.

Waste management(1) -2 Proposed partial submersion method option (RPV filling and solidification)
The partial submersion method option (RPV filling and solidification) is a retrieval method
where the pedestal bottom, RPV, reactor well, etc. are physically stabilized by solidifying withfillers, and then excavates, and retrieves fuel debris with fillers. The issues and countermeasuresof this method are summarized below according to the aforementioned factors ① to ⑥.
⚫

: Because the excavated debris is recovered in a state mixed with water, theissue is to prevent leakage to the outside. It is necessary to examine
detection methods in case of leakage, measures to prevent the spread ofcontamination, and restoration methods after contamination.

Factor ①
Extremely highradiation dose in
PCVs and RPVs⚫

Factor ②
High-radiation dosein reactor buildings⚫

Factor ③
Insufficient on-site
information⚫

: The issue is how to lay the filling hose because it is considered that thefiller materials are injected into the bottom of the pedestal via side-access.
The study is expected to be based on past examples of internal
investigations of the Unit 2 PCV.

: The issue is to achieve a filling condition that ensures excavability byinjecting filler materials. Therefore, it is necessary to consider the selectionof filler materials and procedures that allow them to be filled appropriately
under various conditions. The development should be promoted after
clarifying the functions required for fillers. Moreover, since fuel debris iscovered with fillers, decay heat removal is also an issue, including whether
it is necessary. The possibility that the heat decay removal is inhibitedshould also be considered.

Factor ④: The issues are the seismic feasibility of the cell to be installed in the reactor
the operating floor and securing airtightness. As aseismic assessment should be carried out after
specifying the equipment installed on the operating floor, and thestructures to ensure airtightness should be examined. Thus, the shielding
function required is expected to be reduced compared to proposed partial
submersion method (water injection into RPV). On the other hand,because existing structures such as reactor buildings and PCVs are used
as containment barriers, the same measures will be required as withproposed partial submersion method (water injection into RPV). If fillers
can be used as expected, the impact due to aging degradation is expected
to be mitigated.

Factor ⑤: This has the same issue as with the proposed partial submersion method(water injection to RPV). Measures specific to this option include, forexample, limiting the size of the fuel debris recovery line to a size that will

Building containment building and on
barriers
countermeasure,⚫

Criticality control

19

not cause criticality and adding neutron absorbers to the filler materials in
advance.
⚫

Factor ⑥: The issue is that all filler materials used in large amount must be treatedas radioactive waste. For this reason, reducing the filling range should beconsidered, a plant-wide waste storage plan should be developed to verify
that the waste to be generated can all be stored. Since the excavation
powder recovered from the vicinity of fuel debris is a mixture of fuel debris,
structures, and fillers, the method of sorting fuel debris and waste should
also be considered.

Waste management(2) Proposed Submersion method (Shell structure)
The submersion method (shell structure) involves enclosing the entire reactor building with a
new structure, called a shell structure, as containment barriers, flooding the reactor building, andretrieving fuel debris. Fuel debris inside the RPV and inside/outside the pedestal will be retrieved
via top-access. The issues and countermeasures of this method are summarized below
according to the aforementioned factors ① to ⑥.
⚫

Factor ①
Extremely highradiation dose in
PCVs and RPVs⚫

Factor ②: Effect of the water shielding by submersion allows a person to approach
the middle working framework on which the retrieval work is carried out in
the Shell structure. However, since all work inside the PCV/RPV will be
performed remotely, it is necessary to take similar measures to the onesin the proposed partial submersion method (RPV water injection).
: In some of the preparatory work prior to the installation of the Shellstructure, such as rerouting of RPV injection facilities, work inside thereactor building is required. Thus, it is necessary to take a response similar
to that of the proposed partial submersion method (RPV water injection).

High-radiation dosein reactor buildings⚫

Factor ③
Insufficient on-site
information⚫

Factor ④: To install temporary structures for constructing the shell structure, theissue is that the possibility of soil contamination around the reactor building
cannot be completely excluded. It is also necessary to examine
construction feasibility, assuming that the excavated soil (including
groundwater) is contaminated.。
: In addition to studying the methods based on the uncertainty of on-site
information, the issue is to assemble the bottom of the Shell structure into
the space inside the shield tunnel with only the side access. The feasibilityof welding work and inspection methods should be verified. Another issue
is to prevent contaminated water from leaking outside the Shell structure,
which has three layers of containment barriers. It is necessary to study
measures to detect leakage between the containment barriers and to
recover from leakage. For the integrity of the temporary structures,
surrounding ground, and shell structure during construction andearthquake, the prospects for feasibility have been confirmed throughanalysis and evaluation using the finite element method considering waterpressure (internal water, ground water), earth pressure, seismic load, etc.

Building
containment barriers⚫

Factor ⑤
Criticality control⚫

Factor ⑥: The issues are the same as for the Partial submersion method (water
injection to RPV). In addition, as a countermeasure in case of criticality, theissues are the maintenance/management of boron concentration and thecontrol of the supply of boric acid for a constant boric acid solution
environment.
: Due to the construction of the Shell structure, the amount of waste suchas demolished buildings and excavated soil, which interfere with yard
maintenance, will be enormous, and the same measures as those

Waste management20

proposed for the partial submersion method (RPV water injection) will benecessary.

The above describes issues and measures for each method. While technical issues remain witheach method, there are also complementary technologies (for example, the shielding effect fromusing fillers is a common element technology applicable to both the partial submersion andsubmersion methods).
In the future, it is desirable to extract elements with high technical feasibility, project continuity,and high effectiveness in solving issues out of technologies examined for each retrieval method,and combine them to proceed with examination to establish a more rational and feasible retrieval
method.
3.1.3.5 Continuation of accident analysis activities (clarification of events that occurred at
the accident)
TEPCO has been conducting estimation of RPV and PCV condition and accident analysis, andis reflecting the results in the examination of fuel debris retrieval method and storage management.
On the other hand, since there is still a lack of site information, it is an issue to refine informationon the location of fuel debris and dose distribution in buildings by analyzing and understanding
accidents. Activities to improve understanding of the events during the accident and incorporate
knowledge gained into decommissioning work will continue. Furthermore, the NRA, in cooperation
with TEPCO, is reviewing findings from accident analyses to help investigate the causes of theaccident and improve nuclear safety in the future. With regard to international cooperation, projects
on accident analysis are in progress at the OECD/NEA based on the knowledge of various
countries and organizations.
3.1.3.6 Research and development for further expansion of fuel debris retrieval in scale
For issues that are difficult to address in engineering or far-sighted issues, the Project ofDecommissioning, Contaminated Water and Treated Water Management has been promoting
research and development. This R&D is being carried out in accordance with the R&D mediumand-long-term plan and the next-term R&D plan that are described in Chapter 5.2, and it isimportant to proceed exhaustively, systematically and efficiently while confirming that it is in linewith the needs of TEPCO as the entity responsible for decommissioning. The followings are a listof research and development items being performed. The sections describe research anddevelopment that is common to each method, except for (8). Although (8) is research anddevelopment relating to partial submersion method only at present, those for other methods will be
initiated by identifying research issues as necessary in the future.
(1) Technology for investigation inside the
RPV(5) Analytical and estimation techniques forthe characterization of fuel debris21

(2) Technology for environmental
improvement inside the reactor buildings(6) Technologies for collecting, transportationand storage of fuel debris(3) Development of analytical technology forradiation exposure dose assessment(7) Data acquisition of dust dispersion rate(8) Fuel debris retrieval method(4) Liquid treatment system (α-rays-emitting
nuclide removal technology)
3.1.3.7 Issues in examining safeguards strategies
Since material accountancy and safeguards for the retrieved fuel debris are unprecedented,
TEPCO may face technical issues in examining and applying them to the site. For this reason, NDF
will conduct wide-ranging surveys on existing technologies related to material accountancy andsafeguards to prepare in case that TEPCO needs technical assistance. NDF will also check the
progress of the project from an engineering perspective to confirm that the application ofsafeguards to systems does not affect the decommissioning process.

22

3.2 Waste management
3.2.1 Target⚫

The Solid Waste Storage Management Plan (hereinafter referred to as the “Storage
Management Plan”) is developed and revised with updating the estimated amount of solid waste
to be generated in the next 10 years, as well as appropriate storage/management should be
implemented

includingwaste

prevention,

volumereduction,

andmonitoringofstorage/management conditions based on it.
⚫

Based on the prospects of processing/disposal methods of solid waste and technology related
to their safety presented in FY 2021, the creation of options for processing/disposal measuresand their comparison and evaluation should be conducted with promoting characterization toestablish waste streams that are suitable for the features of solid waste. Proceed study on
specific management of the solid waste to present appropriate measures as a whole.

⚫

Develop and update the analysis plan necessary to advance the consideration ofstorage/management and processing/disposal, and proceed steadily with analysis based on it.

3.2.2 Progress⚫

Since a large amount of solid waste with various characteristics is generated in association withdecommissioning, the efforts based on the following "Basic Policies on Solid Waste” areunderway.

⚫

The Storage Management plan published in February 2023 describes that a considerable
amount of waste (at least about 300,000 m3) is expected to be generated in the preparatory
works for fuel debris retrieval. This amount of waste generated is estimated based on theassumption of uncertainty due to the fact that the fuel debris retrieval method has not been
determined for the dismantling of the buildings around Units 1 to 4 and the resin generated
before the earthquake. In the future, the amount of waste generated will be scrutinized in
anticipation of the volume reduction effects of incineration, crushing, etc.
< Basic Policies on Solid Waste>(1) Thorough containment and isolation(2) Reduction of solid waste volume(3) Promotion of characterization(4) Thorough storage/management(5) Establishment of selection system ofpreceding processing methods inconsideration of disposal(6) Promotion of effective R&D with an
overview of overall solid waste
management(7) Development of continuous
operational framework(8) Measures to reduce radiation
exposure of workers

3.2.3 Key issues and technical strategies
In Phase 3, in order to determine the specifications of waste form and their production methods,
institutions concerned, led by NDF, are conducting technical studies on integrated measures from23

characterization to processing/disposal of solid waste, based on their respective roles. The statusof each area is shown below.
3.2.3.1 Characterization
While accumulating analytical data, inventory for solid waste will be continuously improved, whichis the basic information for solid waste management, including processing/disposal. Although theanalysis work itself is not difficult, low-activity waste has the feature of enormous volume. And thelimited number of analyses data obtained for high-activity waste due to the difficulty of sampling.
Considering their feature, analysis of such waste makes it important to take an approach that
ensures the required accuracy efficiently. For these issues, efforts are being made to establish an
efficient analysis evaluation method.
Capacity of analysis has been enhanced with the completion of the Japan Atomic Energy Agency(hereinafter referred to as "JAEA")'s Radioactive Material Analysis and Research Facility
Laboratory-1 on the premises of the Fukushima Daiichi NPS in June 2022. With that capacity inmind, analyses contributing to solving issues in the decommissioning process will be performed
systematically, considering the priority of samples. As acquired data should be used for overall
waste management, TEPCO should provide comprehensive management of solid waste
characterization, including adjustment of the entire process of collecting samples for analysis,
securing analytical facilities, transporting samples, etc. (hereinafter referred to as “analysis supply
chain”).
In March 2023, TEPCO developed an analysis plan for the characterization and optimization ofstorage/management to discuss solid waste processing/disposal methods. Based on this plan,
TEPCO and the JAEA will work together to incorporate into specific analysis work, review theanalysis plan, Identify the details of necessary technical development tasks, and establish theoperational structure of the analysis supply chain early.
3.2.3.2 Storage/management
Storage/management of solid waste should be appropriately implemented for the risk dependingon radioactivity concentration and properties, etc. Moreover, it is important to reconsider
measurement items and timing, etc., while acquiring necessary information through continuous
monitoring of the storage/management status. Though the current storage/management of solid
waste is based on the classification by surface radiation dose rate, in preparation for the expected
increase in the amount of solid waste generated, it will transit to the management by concentrationof radioactivity and examine the rational classification of waste and reuse on-site based on these.
The Mid-and-Long-term Roadmap calls for eliminating temporary outdoor storage of all solid
waste, excluding secondary waste generated by water treatment and waste subject to reuse andrecycling, by the end of FY 2028. To achieve this goal, it is necessary to develop necessary facilities
and installations systematically including incineration/volume reduction facilities and solid waste
storage, and promote steadily consolidate storage of solid waste inside buildings. In addition, taking

24into account the views of the Study group on Monitoring and Assessment of Specified Nuclear
Facilities and the Technical Meeting on the Examination of the Implementation Plan of the
Measures for the Specified Reactor Facilities, regarding the practicality and rationality of storageof low-level concrete and other waste, an examination will be carried out on storage/management
methods which are safe, reasonable and feasible, such as classification according to thecharacteristics of the main nuclides with a view to long-term processing/disposal.
For ALPS slurry, although there is a delay in installing the ALPS slurry stabilization/treatment
system, the immediate storage capacity has been secured. The upper limit of the integrated
absorbed dose (5,000 kGy) will be evaluated to exceed before the commencement of thestabilization process, and the HICs that needed to be transferred continuously increased. To ensure
storage capacity for HIC and transfer for the time being and to transit to a more stable state,stabilization/treatment system installation and processing will proceed in a planned manner.
Issues and measures for storing/managing high-activity waste to be generated by further
expansion of fuel debris retrieval in scale, which were clarified by fiscal 2021, will be reviewed alongwith examining the fuel debris retrieval methods. Measures will be taken to ensure thestorage/management of solid waste expected to be generated during fuel debris retrieval before
full-scale retrieval. In preparatory works for the retrieval of fuel debris, it is expected that a large
amount of concrete and metal with low radioactivity concentrations will be generated due to thedemolition of buildings, etc. Therefore, it is essential to continue the current measures for reducing
the amount of materials and to conduct a study on the possibility of further reducing.
3.2.3.3 Processing/disposal
To specify a suitable overall picture covering the entire waste stream, the R&D of processing anddisposal technologies required for the series of studies, as shown in Fig.7, will be continued.
Regarding the processing technologies, pending issues in normal-temperature and thermal
processing technology, for which research/development is promoted, will continue to be addressed.
Although the storage capacity of ALPS slurry has been secured for the time being, it will be a
problem to secure storage capacity in the future. Thus, in light of the point at issue regarding slurry
dehydration technologies in the Study group on Monitoring and Assessment of Specified Nuclear
Facilities and the Technical Meeting on the Examination of the Implementation Plan of the
Measures for the Specified Reactor Facilities, the issues related to dehydration should beconsidered sufficiently to discuss requirements in selecting treatment technologies to be applied,with priority. As a matter of immediate consideration, a study will be conducted on a technology forsolidifying a large amount of rubble, which is difficult to separate, in a batch without segregating it,
and on a technology for treating slurry dehydrates and their containers integrally.
Concerning disposal technology, to enhance the reliability of the disposal concept, its feasibility
will be evaluated based on a study of the long-term evolution behavior of the disposal facilities inlight of the characteristics of the waste form to incorporate the results into the discussion of thedisposal concept. To appropriately allocate waste to a disposal concept that is shown to be feasible,

25

knowledge of the sensitivity structure of scenarios regarding disposal and parameters to radiation
doses will be increased to leverage it for proposing safe and reasonable disposal options.
Furthermore, after expanding the target of waste streams incorporating this disposal option, a groupof disposal options will be examined with a bird-eye-view of all solid waste at the Fukushima Daiichi
NPS. Then, contributions will be made to considering appropriate specific management
approaches as a whole in coordination with knowledge gained in areas other than disposal.

Generation ofwaste

Pretreatment andtreatment

Near-term storageand management

・ Improve accuracy of data on
properties, for disposal safetyassessment
・ Acquire additional data,
review transfer models
・ Quantify factors interferingwith waste conditioning

・ Based on treatment
schedules, update plans forrequired timing, capacity,
etc. of storage facilities
・ Update waste classifications
・ Change combinations ofwaste to be treated

Waste conditioning

・ Review waste specification
proposals to meet disposal
requirement proposals
・ Identify technologies that canbe applied
・ Improve quality control
processes

・ Review disposal methods(design of disposal facilities)
and assessment methods(scenarios, models,assessment parameters)

DisposalRequirement
proposals

・ Specify processing
technology suitable for
waste
・ Designate waste
specifications

Policy fornarrowing
down

Disposal・ Specify reasonable andfeasible disposal
methods
・ Conduct disposal safetyassessments

Proposals forprocessing/disposal options

・ Manage risk throughmonitoring and surveillance・ Consider risk reduction
measures as necessary

Processing

Waste
specification
proposals

Storage/management

Stablestorage・ Set inventories

Property
data

Characterization

DisposalReflect in TEPCO and solid
waste storage management plans

Fig. 7 Procedure to reasonably select safe processing/disposal methods of solid waste

26

3.3 Contaminated water and treated water management
3.3.1 Target⚫

Under the three principles concerning the contaminated water issues ("removing"
contamination sources, "redirecting" fresh water from contamination sources, and "retaining"
contaminated water from leakage), the target is to control the amount of contaminated water
generated to less than 100 m3/day or less with the average rainfall by the end of 2025, andabout 50 to 70 m3/day by the end of FY 2028, while continuing the operation of the constructedwater-level management system. Moreover, to ensure the stable implementation ofcontaminated water management, measures for mitigating large-scale natural disaster risks,such as tsunamis and storm rainfall, will be implemented in a planned manner.

⚫

To arrange the relationship with a decommissioning process including full-scale fuel debris
retrieval beginning in the near future, and to promote examination of the measures of thecontaminated water management for medium-and-long term prospects.

⚫

To discharge ALPS-treated water safely and reliably to secure the site and other resources
and steadily advance the entire decommissioning process.

3.3.2 Progress⚫

The amount of contaminated water generated decreased from about 490 m3/day (FY 2015)
before management was in place to about 90 m3/day (FY 2022). Although the figure fell below
the milestone of about 100 m3/day set out in the Medium-and-Long-term Roadmap, theachievement of the milestone will be evaluated based on data from FY 2023 onward in light of
the fact that the amount of rainfall in FY 2022 was less than the average year.

⚫

In FY 2022, a milestone in the Medium-and-Long-term Roadmap was achieved: “to reduce thestagnant water in reactor buildings in FY 2022 to 2024 to about half of the level at the end of2020”.

⚫

As a countermeasure for heavy rain, a new drainage channel D was installed to contribute toeliminating the risk of inundation in the vicinity of Units 1 to 4. In addition, widening andbypassing of the existing drainage was completed in February 2023.

⚫

Based on the implementation of the basic policy presented at "the sixth meeting of the InterMinisterial Council concerning Decommissioning, Contaminated Water, and Treated Water
Management" and the " the sixth meeting of the Inter-Ministerial Council concerning theContinuous Implementation of the Basic Policy on Handling of ALPS Treated Water" and future
efforts, ALPS treated water was discharged to the sea on 24 August 2023. Communication onvarious occasions, such as briefings, and information dissemination through various media
including the treated water portal site, have been promoted.

27

3.3.3 Key issues and technical strategies
3.3.3.1 Control of contaminated water generation amount
Toward the goal of limiting the amount of contaminated water generated to about 50 to
70 m3/day by around the end of FY 2028, local water sealing work in the building will be carriedout, in addition to lowering the water level of sub-drains and work of facings around Units 1 to 4.
In the gaps between buildings, which are the main factors of groundwater inflow into buildings,
there are nearly 200 sites of penetration at T.P. -0.65 m, the current sub-drain water level (L value).
If the water level is lowered to the assumed groundwater level in FY2025 (about T.P. -1 m), thenumber of penetration sites will be reduced by almost half, which is expected to reduce the inflow
to buildings. However, there will still be nearly 100 penetration sites below T.P. -1 m.
To suppress groundwater inflow from the penetration sites of these gaps, the plan is to establish
a water seal part by boring holes at the ends of the gaps between buildings and filling them withmortar, etc. As for the water seal at the ends of the gaps, after conducting tests on construction
methods and materials using test specimens off-site, and test construction will be carried out at
Units 5 and 6, then results will be deployed in Unit 3. In addition, water sealing at penetration sitesof the exterior walls of the buildings and facing of the areas around the buildings will be carriedout in parallel while coordinating with other decommissioning work, targeting at the end of FY2028(about 50–70 m3/day).
3.3.3.2 Treatment of stagnant water in buildings(1) Further reduction of stagnant water
Due to the presence of high-radiation dose sludge containing cesium and α-nuclides near thefloor of the reactor building, lowering the water level of the building too much may lead to reduced
water shielding effect and deterioration of the working environment.。Moreover, if contaminatedwater with a radioactivity concentration several orders of magnitude higher than usual flows into
the cesium sorption apparatus, the purification performance may be significantly degraded.
Although reducing the amount of stagnant water in the reactor building to about half the level atthe end of 2020 has been achieved, setting a new goal to reduce the stagnant water should beconsidered in integration with the fuel debris retrieval method, and shifted to the steps of stablestagnant water control through decommissioning work.
(2) Stagnant water treatment in the process main building and high-temperature incinerator
building
At present, stagnant water in the building is also stored on the basement floors of the process
main building and the high-temperature incinerator building, and the plan is to reduce the waterlevel toward the exposure of the floor surface, starting in FY 2024. On the basement floors ofthese buildings, zeolite sandbags, etc., which were installed immediately after the accident toimprove the water quality of the stagnant water, are present in a high dose state, and if the floor
surface is exposed on the basement floors, it is expected that the radiation dose on the floors
above ground will increase significantly because there will be no water shielding. Therefore, the28

planned procedure is to first collect as many zeolite sandbags as possible in a submerged
environment, then transfer them to the floors above ground using a recovery robot, seal theminto storage containers after dehydrating in the building, and transfer them to temporary storage
facilities.
In addition, temporary storage facilities for stagnant water are being designed, which will takeover the function of a buffer tank that has been performed by the process main building and hightemperature incinerator building. The temporary storage facilities for stagnant water havebecome much smaller than before, and a plan needs to be developed from an operational
perspective to maintain their function even with a smaller capacity.
3.3.3.3 Issues of contaminated water management considering the decommissioning
process such as fuel debris retrieval(1) Examination of water treatment systems for dispersion prevention of α-nuclides andfuel debris retrieval
The relatively high total alpha concentrations have been detected in the stagnant watercollected from the bottom of the torus room of the reactor building, and they have been confirmed
to exist mainly in the form of granular particles (alpha sludge). As a preparation for increasing
the amount of sludge in the contaminated water with the progress of decommissioning, theinstallation of a filter facility in the latter stage of the cesium sorption apparatus is being examined
to prevent the spread of α-nuclides to the downstream side.
With regard to water treatment systems for fuel debris retrieval, it is important to examine thetiming and method of retrieval and the performance of the treatment facilities required at thattime in a consistent manner. When retrieving fuel debris, contaminated water containing fineparticles in large quantity will be generated by processing, such as cutting and other processes,
and α-nuclides in fuel debris may transfer to the stagnant water in various forms such as fineparticles, ions, and colloids. Therefore, since the water quality of contaminated water depends
on the method of cutting and other processing, in the situation where the fuel debris retrieval
method is not determined, the challenge is that the water treatment system needs to deal with awide range of conditions. To establish processing methods for fuel debris, by performing
laboratory tests, an examination should be carried out to identify the impact on the water qualityof contaminated water. This will allow the establishment of more realistic water quality conditions
for contaminated water, leading to streamlining the water treatment systems and improving thereliability.
(2) Medium-and-long term measures for contaminated water management systems
To maintain the effectiveness of contaminated water management over the medium-to-long
term, it is necessary to implement periodical inspection and updating of equipment for land-side
impermeable walls, sub-drain systems and existing water treatment systems (e.g., SARRY,
ALPS) without fail. To this end, it is important to assume various risks such as aging, strengthen
the system for monitoring and early recovery measures, arrange procurement of spare and29

replacement parts for stable operation, and proceed with maintenance and equipment renewal
in a planned manner.
In addition, since it will take a long time to complete the retrieval of fuel debris, the challenge
is to take a bird's-eye view of contaminated water management in the medium to long term andto establish a more stable contaminated water management and a more appropriate
maintenance and management system for each equipment, in conjunction with the selection of
methods for further expansion of fuel debris retrieval in scale that is currently underway. With
this, these studies should be carried out after considering the interference with the work of fueldebris retrieval.
3.3.3.4 Future efforts for the discharge of ALPS-treated water into the sea
The discharge of liquid waste generated in nuclear facilities into the sea, pursuant to the law,with a sufficiently small radiological impact on the human population and the natural environmentis a globally method recognized and is adopted widely in Japan and abroad. The IAEA has
published a review finding that activities related to the discharge of ALPS-treated water into the sea
are consistent with relevant international safety standards and have a negligible radiological impact
on humans and the environment. It is necessary to disseminate highly transparent information
based on scientific evidence, including the above, to prevent the impact of reputational damage.
Based on the Action Plan for Steady Implementation of the Basic Policy on the Disposal of ALPS
Treated Water formulated by the government, it is essential for TEPCO to reliably operate thefacilities in accordance with its own plan for the discharge of ALPS-treated water into the sea andcommunicate the status with high transparency.
(1) ALPS-treated water analysis and evaluation structure
Fig. 8 shows the analysis and evaluation structure of ALPS-treated water collected at themeasurement and confirmation facilities. In addition to its own analysis before the discharge tothe sea, TEPCO outsources to independent external organizations and performs analysis every
time to determine whether or not to discharge according to regulatory standards. The JAEA
Okuma Analysis and Research Center (Radioactive Material Analysis and Research Facility
Laboratory-1) also conducts analysis every time before the discharge in accordance with thegovernment’s basic policy. Moreover, the NRA (commissioned to the JAEA Nuclear Safety
Research Center) and the IAEA (laboratories belonging to the IAEA and research institutes inthird countries) also conduct analysis of ALPS-treated water as appropriate to confirm theanalytical quality submitted by TEPCO. In May 2023, the IAEA concluded in its "Report on the
results of the first inter-laboratory comparison of radionuclide analysis of ALPS-treated water"that TEPCO has the ability to analyze ALPS-treated water accurately and precisely, and sampling
procedures and nuclide analysis methods are appropriate.

30

In this manner, several institutions are conducting various third-party analyses of pre-discharge
ALPS-treated water for comparison with the analysis data disclosed by TEPCO. It is importantthat those data are made publicly available in a prompt and transparent manner.

Verification and monitoring
by NRA

Analysis of ALPS-treated water
Selection of radionuclides

The Secretariatof the NRA

TEPCOCommissioned

Verification

Tokyo PowerTechnology Ltd.

Commissioned

Cross-check by
TEPCO-third party

JAEA Nuclear Safety
Research Center

Regulatory review by IAEA

Analysis agent
independent from TEPCO

Data corroboration and analysis by IAEA
Treated water safety review by IAEA

Highly objective and transparent measurements(Initiatives based on government policy)

IAEA Analysis laboratory

Verification/publicationby third-party

Independent third-party
analysis agency

Third-parties with expertise in analysis forradioactive material
JAEA Okuma Analysis and Research Center
Laboratory-1 of Radioactive Material Research Building(Source: NRA)
Fig. 8 ALPS-treated water analysis and evaluation structure(2) Periodic verification of nuclides to be measured and evaluatedAs the target nuclides to be measured and evaluated before discharge of the ALPS-treatedwater into the sea, 29 nuclides were selected after re-examining the nuclides that could becontained in the contaminated water before treated by cesium sorption equipment, ALPS andother systems in significant amounts, based on knowledge of decommissioning and buried
facilities at nuclear power plants in Japan.
When discharging into the sea, a check is performed to ensure that the sum of the notified
concentration limit ratios of the selected nuclides to be measured and evaluated is less than 1.
However, it may change depending on the progress of decommissioning work in the future, it isnecessary to confirm that there are no significant nuclides other than the selected nuclides to bemeasured and evaluated (hereafter referred to as “other nuclides”.) If significant amounts of othernuclides are present, the nuclides to be measured and evaluated will be reevaluated, and an
environmental impact assessment will be performed as needed.
(3) Strengthening and enhancing marine environmental monitoring
In March 2022, in the Monitoring Coordination Council chaired by the Minister of theEnvironment, the Comprehensive Monitoring plan was revised based on expert advice, and in
April, marine monitoring began before discharge into the sea. In addition to TEPCO, the Ministryof the Environment, the NRA, and Fukushima Prefecture are also supposed to monitor the same
marine areas independently in marine areas near the Fukushima Daiichi NPS. A framework has

31been established for each of them, including TEPCO, to conduct with enhanced objectivity andtransparency. Moreover, immediately after the start of the ocean discharge, they are conducting
swift analysis and publicizing the results in a preliminary report.
Furthermore, analysis of supporting data and inter-analytical laboratory comparison (ILC) wereconducted by the IAEA to ensure the reliability of monitoring. In June 2022, the report of the interanalytical laboratory comparison was published, and the sampling method of the Japanese
analytical institutions were evaluated as adequate, highly accurate, and competent.
To prevent reputational damage, it is important to expedite analysis and disseminate
information on monitoring results that is easy to understand in a timely manner. Marine
monitoring requires sophisticated analytical techniques and long-time measurements to detectextremely low concentrations of radionuclides. Therefore, to expedite the analysis, in addition to
the development of pretreatment technologies for concentrating radionuclides, operational efforts
are being made, such as the disclosure of preliminary data from short-time analysis and final
data from long-time analysis at different times.
For information dissemination, TEPCO publishes monitoring results on its Treated Water Portal
Site and provides the latest information to international audiences in multiple languages. In
addition, TEPCO also launched the Overarching Radiation-monitoring data Browsing System inthe coastal ocean of Japan (ORBS) website in March 2023.
Since multiple organizations, including TEPCO, the Ministry of the Environment, the NRA, andFukushima Prefecture, conduct sampling and analysis as marine monitoring, it is important tooperate the system continuously so that these pieces of data are disclosed promptly andtransparently.
(4) Future operational plans, etc.
TEPCO should continue to conduct checks and reviews on the operational performance of the
facilities for the discharge of ALPS-treated water into the sea and the results of marine
environmental monitoring, and review and expand the plan flexibly as necessary. Then, toward
the prompt and reliable implementation of site usage after the release of treated water, it isnecessary to appropriately develop a discharge plan in accordance with the site use plan whileconsidering the concentration/decay of tritium contained in treated water in tanks and attenuation.
Moreover, it is essential to provide education and training in a planned manner, including forcontractors engaged in system operation and analysis, in order to proceed with decommissioning
work safely and steadily.
The IAEA is committed to continuously reviewing the safety assurance measures taken by thegovernment and TEPCO before, during and after the discharge, and a system has been
established in which IAEA personnel are stationed at the Fukushima Daiichi NPS before andafter the discharge to continue the confirmation. It is important for the government and TEPCO
to continue sharing the necessary information with the IAEA, and provide explanations to Japanand the international community based on scientific evidence with a high degree of transparency.

32

NDF will provide technical and professional support for TEPCO’s planning and operation ofcountermeasures on contaminated and treated water, while promoting the distribution of
accurate information and increasing understanding in line with the interests of those who will
receive the information, through meetings and conferences with relevant domestic and overseasorganizations. NDF will also ensure that measures to minimize reputational damage are
implemented by TEPCO and that action is taken with adequate and sufficient compensation in
the event of reputational damage.

33

3.4 Fuel removal from spent fuel pools
3.4.1 Target⚫

To complete fuel removal from the spent fuel pools of all Units from 1 to 6 by the end of 2031.

⚫

As the return of residents and reconstruction in the surrounding area gradually advances, tocarry out a risk assessment and ensure safety, including preventing the dispersion ofradioactive materials, and to start removal of fuel in SFPs in FY 2027 to FY 2028 for Unit 1
and FY 2024 to FY 2026 for Unit 2.
The fuel in Units 1 to 4, which were affected by seawater and rubble, is retrieved from the⚫

SFPs and transferred to the Common Spent Fuel Storage Pool, etc., where it is appropriately
stored to be in a stable management state. In order to secure the Common Spent Fuel Storage
Pool capacity, the fuel stored there is transferred to and stored in the dry cask at the Temporary
Cask Custody Area.
To perform the evaluation of long-term integrity and the examination for treatment for the⚫

retrieved fuel and to decide the future treatment and storage method.
3.4.2 Progress⚫

Unit 1 :⚫

Unit 2 :⚫

Unit 3 :⚫

Unit 6 :Work is underway to assemble a large cover frame in the off-site yard in parallel
to installing a lower frame in the reactor building.
The installation of the working platform base mat for fuel removal was completed
in November 2022, and erection of steel structure began in January 2023. In
addition, the south side of the spent fuel pool was fully cleared of obstacles inMarch 2023, and decontamination work is underway.
Removal of high-radiation dose equipment from the spent fuel pool began in
March 2023.
The fuel transfer process from the Common Spent Fuel Storage Pool to the drycask at the Temporary Cask Custody Area has been reconsidered due to theimpact of the contamination with foreign substances, causing a delay in theprocess of transferring spent fuel to the Common Spent Fuel Storage Pool.

3.4.3 Key issues and technical strategies
3.4.3.1 Fuel removal from spent fuel pools
For Units 1 and 2, it is necessary to advance the work steadily to realize the new retrieval methodthat has been determined.
In promoting the project, it is essential to evaluate safety in association with work, to confirm thatnecessary and sufficient safety is ensured, and then to comprehensively consider the technicalreliability, rationality, the promptness of the work schedule, the actual site applicability, the projectrisk, etc., in order to address issues.
(1) Unit 1⚫

Since the overhead crane is unstable on the upper part of the operating floor, removing theit in a safe and reliable way is one of the main issues. Therefore, in the ongoing examinationof how to remove the overhead crane, it is assumed that safety assessments will be34performed, and it is important to carry out acomprehensive

examination

in

light

of

rationality and impact on other operations by:
Formulating specific work procedures and⚫

work plans enabling identification of risk items
Anticipated

⚫

risk

scenarios

andcountermeasures
Identifying⚫

pointstoconsider,

such

as

exposure of workers, from the operator's
perspective

Fig. 9 Overview of the rubble removalfrom Unit 1 operating floor

The information on the condition of the lower part of the roof slab is limited at present, requiringa detailed investigation after the removal of the slab. Since there is a risk that the cranedismantling process may be delayed depending on the investigation results, investigation should
be carried out promptly once it becomes possible, and the results should be incorporated into
the safety assessments and rubble removal plans. (Fig. 9)
Regarding the contamination state of the well-plugs of Units 1 to 3, it has been pointed out thatthe well-plugs have important implications for safety and decommissioning work due to the highlevel of their contamination. Although the contamination level of the well-plug of Unit 1 is lower
than that of Units 2 and 3, it is unstable due to the impact of the accident, and examination is
being made on measures to deal with the situation. From now on, a comprehensive decision on
how to deal with well-plug should be made based on these examination results and by taking
into consideration the impact on fuel removal from SFPs and fuel debris retrieval and performing
thorough safety assessments.
A detailed handling plan for 67 fuel assemblies with damaged cladding tubes, which have been
stored in the Unit 1 SFP since before the accident, is under development toward the completionof fuel removal in 2031. In particular, efforts should be made to ensure verification of the postaccident condition and risk study associated with handling.
(2) Unit 2
Fuel in FSP will be removed from the opening on the south side of the operating floor using afuel handling machine composed of a boom-type crane-system that has never been used atnuclear facilities in Japan before (Fig. 10). Since this is a new system, the following measures
should be taken without fail.
⚫

Development of appropriate design and production schedules with margin⚫

Conducting of mock-up tests that sufficiently simulate on-site conditions and operating
method, and reliable feedback of these test results into design and production35⚫

Sufficient mastery of system operationand functionality in advance due to theReactor Building

remote-controlled nature of the retrieval

Front
Chamberwork
Fuel handling facility

Fuel removal from pools will be conductedWorking
platform

Working platform
for fuel removal

Runway girder

basically by remote-controlled unattended

Base matoperation, but it is also assumed that some
fuel removal will be performed by manned

Fig. 10 Fuel removal method in Unit 2 SFP

operation. Therefore, it is important to reducethe dose on the operating floor as much as possible, and decontamination and installation ofshielding are being carried out. After decontamination, the opening is scheduled to be installedon the south side of the operating floor, and as there is a risk that the work area may becontaminated again, thorough measures to prevent dust dispersion should be taken during
installation of the opening.
(3) Removing high-radiation dose equipment
Removal of high-radiation dose equipment is ongoing in light of risk reduction in the event ofpool water leakage. It is also possible to exclude pool water from management by draining thepool water after removing the high-radiation dose equipment, leading to smooth fuel debris
retrieval operation in the later stages because of the increased flexibility of use of the operating
floor. Prior to draining the pool water, the radiation dose and dust dispersion from the pool afterdrainage should be evaluated to confirm safety in advance.
To remove high-radiation dose equipment, it is effective to utilize the devices used for fuel andrubble removal. The fuel removal system for Unit 1, which will be installed in the future, should
also be designed and maintained in anticipation of the removal of high-radiation dose equipment.
Moreover, because the capacity of existing site bunkers for storing high-radiation dose
equipment is limited, it is important to proceed with constructing new site bunkers.
3.4.3.2 Decision on future treatment and storage methods
The future treatment and storage methods for fuel in SFPs needs to be decided after
considering the impact of seawater and rubble at the accident and the damaged fuel stored since
before the accident. Future treatment and storage methods should be determined in light of thecondition of the fuel to be removed while examining the long-term integrity assessment andtreatment. TEPCO plans to transfer fuel in SFPs of all Units to the Common Spent Fuel Storage
Pool by the end of 2031. Subsequently, taking into account the tsunami risk, the possibility of dry
storage on higher ground has been studied, including existing fuel in the Common Spent Fuel
Storage Pool. In addition to the existing metal casks, TEPCO has announced that it will study theapplication of concrete casks using canisters with proven track records overseas, as dry storage
facilities. The dry storage facilities to be applied, including storage of damaged fuel, should be36

determined based on the advantages and disadvantages of both the casks and the characteristicsof the Fukushima Daiichi NPS.

37

4. Analysis strategy for promoting decommissioning
4.1 Significance of analysis on decommissioning
In the decommissioning of the Fukushima Daiichi NPS, only a few records exist, such as fortemperature, and there are many uncertainties regarding the status inside the reactors, thecondition of fuel debris, the release path of fission products, and so on. In decommissioning the
Fukushima Daiichi NPS, analysis with various analysis targets, purpose of analysis, and radiationdose rates must be performed, as shown in Fig. 11.

Purpose of analysis（Needs）

Equipment required for characterazartion✓ Storage management ✓Processing and disposal✓ Investigation of accident history✓ Storage management✓ Processing and disposal✓ Assessing contaminationlevels✓ Environmental monitoring

Hot cellFuel debris

Generalliving environment✓ Retrieval method✓ Safeguards✓ Storage management ✓Processing and disposal✓ Investigation of accident history✓ Confirmation for discharge

Glove box

Hood

Waste generated fromfuel debris retrieval
Secondary waste generated by water treatment
Zeolite sandbags
Rubble, etc.

Environmental samples
ALPS-treatedwater

10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1
Radiation dose rate (Sv/h)

1

10

Fig. 11 Relationship between the purpose of the analysis, equipment required forcharacterization, and radiation dose rates of the analysis targets
If the properties of fuel debris can be ascertained by analysis, an excessive margin in
decommissioning work can be eliminated by reducing the uncertainty range, and the rapidity andrationality of decommissioning can be improved. In addition, when considering theprocessing/disposal measures of solid waste, the property data such as nuclide composition andradioactivity concentration obtained by analysis will serve as basic information. Since ALPS-treatedwater is assumed to be released to the environment, it should be confirmed that it is sufficiently
below the release standard value by analysis. Adequate results obtained from these analyses areindispensable for achieving these conditions and for the safe and steady progress of
decommissioning work at the Fukushima Daiichi NPS. In order to obtain the appropriate analysis
results, it is effective to improve the three elements of the analysis strategy for fuel debris (Method
and system of analysis, quality of analysis results, size and quantity of samples).

384.2 Current status and strategies for analysis
4.2.1 Measures to strengthen analytical method and analysis structure(1) Measures to strengthen analytical structure
To strengthen the analysis structure necessary for decommissioning the Fukushima Daiichi
NPS, TEPCO, the JAEA, NDF, and other related organizations have been working together bystudying analysis plans, developing analysis and evaluation methods, securing analysis facilities,
and recruiting analysis personnel. In addition, the NRA has also suggested that measures toimmediately resolve issues should be examined (such as an all-Japan approach) to strengthen
the analysis system, the Agency for Natural Resources and Energy reports on these efforts andthe immediate responses. We will continue to steadily implement our immediate efforts and takenecessary actions based on the situation.
(2) Discussion on analysis plans
The growing demand for analysis as the decommissioning process progresses must be
handled flexibly and systematic preparations must be made so that the decommissioning work
does not stagnate due to analysis. TEPCO extracted wastes with high priority for analysis basedon the progress of analysis and risks associated with storage management, and reviewed thecharacterization policy and analysis plan according to the characteristics of each waste. In
addition, after integrating and coordinating analysis plans for each type of waste, TEPCO designs
the annual development of the necessary analysis capabilities and incorporates them into
analysis personnel plans. This analysis plan is continuously updated to reflect changes in needs
as decommissioning progresses. Moreover, TEPCO will implement the initiatives in the plan and,based on the progress made, will constantly review the necessary measures.
(3) Development of analysis and evaluation methods
Solid waste has the characteristics of many types of waste in huge amounts. Therefore,
efficient characterization is necessary. For this reason, we have developed analytical methods
to obtain data easily and quickly, and have established methods of characterization with a small
amount of analytical data in the Project of Decommissioning, Contaminated Water and Treated
Water Management. As part of this effort, analytical methods that have been accelerated bystreamlining and automating pretreatment of sample are being standardized. In addition, efforts
are being made to develop analytical methods to deal with various sample forms and the difficultto-measure nuclides.
(4) Securing facilities for analysis
The JAEA’s Radioactive Material Analysis and Research Facility (Laboratories 1 and 2) has
the advantage that off-site transportation is not required because the facility is defined as facilities
in the peripheral monitoring area of Fukushima Daiichi NPS. For this reason, analyses that
require hot cells, such as fuel debris, should be conducted in the Ibaraki area as necessary, andanalyses with high promptness should be prioritized on the site of the Fukushima Daiichi NPS

39

and its adjacent areas. It is effective to expand the analysis data under such an assignment ofroles according to the characteristics of each facility for analysis.
(5) Securing human resources for analysis
In each facility for analysis, securing and maintaining analytical personnel to continue stablefacility operation is a challenge. It is necessary to consider in advance the qualities expected ofanalytical personnel in various types of analytical work and develop analytical personnel in aplanned manner to achieve the required roles appropriately. Because the decommissioning of
the Fukushima Daiichi NPS will directly handle unsealed alpha-ray emitters, which are not usuallyhandled by conventional reactors, TEPCO will have to train personnel in fields with little
experience in a short period. The development of analytical engineers should be efficiently
promoted with the cooperation of relevant organizations with sufficient knowledge andexperience in handling alpha-ray emitters. As the demand for analysis is expected to increase in
the future, there will be a need for highly skilled personnel capable of analysis planning in
anticipation of how the analysis results will be used. Analytical evaluators in charge of this task
are required to have the ability to (i) appropriately incorporate the evaluation results into the areas
required for the decommissioning process (retrieval method, safeguards, storage/management,
and processing/disposal), (ii) provide appropriate instructions for the subsequent sampling, and(iii) logically and accurately understand accident events from analytical results. However, it isdifficult for individuals to have all these abilities. Therefore, the Analysis Coordination Meeting
and an Analysis Support Team were organized within NDF (Fig. 12). The Analysis Coordination
Meeting is responsible for confirming analysis plans and providing advice on problem-solving in
response to the increased types and numbers of objects to be analyzed. The Analysis Support
Team, consisting of researchers and engineers with extensive experience and knowledge inanalytical practice, is to examine and discuss specific R&D approaches and the methods tocheck reliable analytical techniques in order to solve problems.

40Fig. 12 Role of the Analysis Coordination Meeting and Analysis Support Team4.2.2 Improvement of the quality of analysis results
It is difficult to accurately identify and quantify all elements and isotopes of fuel debris up to small
components by analysis. As such, it is important to have a multifaceted point of view on theanalytical results of samples in consideration of the impact of the error factor. As part of theverification of sample analysis results, through studies in light of existing findings, such as resultsof analysis, investigation and testing, deriving consistent property evaluations will improve thereliability of analysis results, leading to higher quality of the analysis results. To do so, the JAEA,
the NFD, MHI Nuclear Development Corporation, and Tohoku University have been cooperating toconduct chemical analysis and structural analysis using the same samples since FY 2020.
Currently, Ibaraki area offices are preparing to analyze the Three Mile Island Unit 2 reactor (TMI-2)
debris using the latest technologies to expand the fuel debris data.
As for waste, to perform characterization of all solid waste which exists in large amounts using
the limited analytical data, an efficient approach to ensure the required accuracy will be essential,and efforts are being made to establish an efficient analytical evaluation method. Accuracy is oneof the indicators for the quality of analytical data is the accuracy such as the uncertainty and thelower limit of detection, but accuracy and measurement time are interrelated, and it is expectedthat increasing the measurement time can improve the accuracy. However, if measurements takeweeks or months, it is difficult to keep up with the increasing volume of analysis. Therefore,
according to the analytical purpose, objects to be analyzed, and analytical method, it is also

41

important to properly select the accuracy, measurement time, and measurement frequency basedon the concerned analysis method.
4.2.3 Diversification of analytical techniques to increase sample size and volume(1) Comprehensive evaluation by diversified analysis and measurement methods
Since density, hardness, and other items cannot be measured for micro or very small quantityof samples, it is necessary to increase the size and quantity of samples in accordance with theprogress of the fuel debris retrieval process. Analysis in hot cells is time-consuming, and theamount of use for each nuclide handled is specified, making it difficult to analyze large quantities.
Therefore, it is necessary not only to focus on increasing the quantity of analysis in hot cells but
also to diversify analysis and measurement methods. It is effective to assess the analysis items
obtained by other methods, consider complementing analysis items depending on the use of theanalysis results, and make comprehensive evaluation.
(2) Use of sample analysis and non-destructive assays
One method is to evaluate the amount of nuclear fuel or radioactivity without destroying thesample (hereinafter referred to as “non-destructive assay”). Although non-destructive assays canmeasure fewer items, the measurement time is shorter than that of sample analysis, and a larger
quantity can be measured per measurement. Moreover, measurement can be performed withthe object stored in a sealed container to prevent the spread of contamination, which has theadvantage of no radioactive liquid waste generated. However, since fuel debris has impediments
to nondestructive assays, such as neutron absorbers, it is necessary to verify the extent to whichthese impediments affect measurements. Therefore, technology development aiming at on-site
application is underway through simulation analysis and actual measurement tests. If thisnondestructive assay can quantify the nuclear fuel of the fuel debris in the container, prompt
analyses can compensate for the small number of analyses. When increasing the number ofanalyses, it is desirable to keep the range of uncertainty in the properties of fuel debris as small
as possible while increasing information about the samples, including the coordinate information
at sample collection, to improve the reliability of the data.

42

5. Efforts to facilitate research and development fordecommissioning of the Fukushima Daiichi NPS
5.1 Significance and the current status of research and development
At present, as trial retrieval of fuel debris is about to begin, it is necessary to accelerate researchand development in consideration of the practical application on site for a gradual expansion of theretrieval scale and further expansion of fuel debris retrieval in scale. Under these circumstances,various industrial-academic-governmental institutions, including overseas enterprises, areengaged in basic/fundamental research and applied research by researching institutions, practicalapplication research by manufacturers, and field demonstrations. For application research andpractical application research for decommissioning, the Government provides support to the R&D
carried out by each organization to solve highly-difficult issues through the “Project ofDecommissioning,

ContaminatedandTreated

Water

Management”

and

to

promotebasic/fundamental research and human resource development by universities and researching
institutions in Japan and overseas through the “Nuclear Energy Science & Technology and Human
Resource Development Project” (hereinafter referred to as the “World Intelligence Project”). In
addition to discussing R&D medium-and-long-term planning and next fiscal year R&D planning andsupporting the World Intelligence Project, NDF has also established the Decommissioning R&D
Partnership Council to strengthen coordination between the Project of Decommissioning,
Contaminated and Treated Water Management and the World Intelligence Project (Fig. 13).
Given that the progress of investigation inside the reactors has clarified on-site needs indecommissioning and TEPCO has begun full-scale engineering work for fuel debris retrieval, theleading players in the Project of Decommissioning, Contaminated Water and Treated Water
Management have shifted from the current International Research Institute for Nuclear
Decommissioning (IRID)-centered structure to a new R&D structure comprised of researching
institutions and manufacturers as key implementers based on TEPCO’s needs, requiring smoothcoordination between the R&D implementers and TEPCO. In addition, the Fukushima Institute for
Research, Education and Innovation (F-REI) was established by the Government in April 2023 tocontribute to the reconstruction and revitalization of Fukushima. NDF will continue to gather
information on research and development and human resource development in F-REI and work
together on the basis of its implementation.

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Ministry of Economy, Tradeand Industry
Project ofDecommissioning andContaminated Water
Management

Ministry of Education, Culture,
Sports, Science, and Technology
Support for proposals for the next
Decommissioning R&D plan *6

Operatingcost subsidy

Support *7

Support fordevelopment/operation

Assistance

JAEA

NDF

Fund establishment corporation

Technical committees for decommissioning, etc.

Project
implementation*1(Constitution)
NDF, JAEA, TEPCO, IRID, manufacturers, Decom. Tech,
related experts, the Ministry of Economy, Trade, and Industry,
the Ministry of Education, Culture, Sports, Science, andTechnology

Sharing and planning oftechnical development
information

Collaborative
Laboratories for
Advanced
Decommissioning
Science (CLADS)

Participation

Administrative
instructions

Joint
Application,
etc.

TEPCO
Holdings

Project Management Operation

A company
making a contract

Participation

Basic research for decommissioning
Platform
Companies in Japan andoverseas companies, IRID

Consignment

Secretariat

Consignment
and joint research Project
implementation

Exchange of research needs
and seeds
Bridge-building for results

Subsidized company

Research institutions, Manufactures,etc. (including overseas
companies)

Foreigngovernmentorganization

Okuma Analysis andResearch Center

Cooperative relation

Participation

Cooperative relation

Naraha Remote Technology
Development Center

Decommissioning R&D
Partnership Council

Assignment

Secretariat*5
Assistance

Fukushima research anddevelopment department

Fund for Countermeasures for Decommissioning
and Contaminated Water Treatment

Assistance

Nuclear Energy Science &Technology and Human Resource
Development Project

Universities,
research
institutions,etc., inJapan

Overseas

Joint
universities
researchandresearch
institutions

Cooperation
Joint Research

Universities*1 The Decommissioning R&D Partnership Council is established in the NDF based on the determination by Team for Countermeasures for Decommissioning and Contaminated Water Treatment.
*2 The arrow drawn in a thick solid line indicates expenditures such as research expenses and operating expenses (excluding facilities expenses), the arrow drawn in a thin solid line indicates a cooperative relation, etc., and the arrow drawn in adotted line indicates the participation in the Decommissioning R&D Partnership Council.
*3 Some organizations such as JAEA are located at two or more places.
*4 Each organization has cooperative relations with foreign organizations based on MOU, etc., respectively.
*5 Although among the World Intelligence Project for Nuclear S&T and Human Resource Development the part adopted up to FY 2017 is the consignment from the Ministry of Education, Culture, Sports, Science, and Technology to a company
making a contract, it is omitted in this figure.
*6 With regard to the Project of Decommissioning and Contaminated Water Management, based on the policy in the Mid-and-Long-term Roadmap or Strategic Plan and the progress situation of research and development, the NDF formulates a
draft plan of the next research and development, and the Ministry of Economy, Trade, and Industry determines it.
*7 NDF participates as a member in a steering committee of the World Intelligence Project for Nuclear S&T and Human Resource Development.

Fig. 13 Overview of the R&D structure of the decommissioning of Fukushima Daiichi NPS

5.2 Key issues and strategies
5.2.1 R&D medium-and-long-term plan
NDF and TEPCO have been preparing the R&D Medium-to-Long-term Plan for thedecommissioning of the Fukushima Daiichi NPS. The plan overlooks the overall research anddevelopment in the next 10 years for decommissioning, so that R&D activities for decommissioningof Fukushima Daiichi NPS can be promoted comprehensively, systematically, and efficiently. Basedon the engineering schedule of TEPCO, the R&D medium-and-long-term plan is developed to
identify the required R&D and appropriately incorporate R&D results when needed. The plan has
also included basic/fundamental research since FY 2022.
In FY 2023, the R&D Medium-to-Long-term Plan was revised in light of the medium-to long-term
technical issues that are being discussed by four parties, including TEPCO, Tousou Mirai
Technology Co. Ltd., Sector of Fukushima Research and Development, Fukushima ResearchInstitute, Collaborative Laboratories for Advanced Decommissioning Science of the JAEA,(hereafter referred to as “JAEA/CLADS”), and NDF.
5.2.2 Initiatives for the Project of Decommissioning, Contaminated Water and Treated Water
Management
NDF has been supporting the Project of Decommissioning, Contaminated Water and Treated
Water Management each fiscal year by developing the Next-fiscal year R&D plan over the next two
years. When identifying issues in the Next fiscal year Decommissioning R&D plan, it is important44

to identify them exhaustively, confirm whether it is in line with the needs of TEPCO, and aim for the
R&D results to be utilized for TEPCO’s engineering.
Furthermore, given that the progress of investigation inside the reactors has clarified on-siteneeds in decommissioning and TEPCO has begun full-scale engineering for fuel debris retrieval,the main operator of the Project of Decommissioning, Contaminated water and Treated water
Management was shifted from the IRID to a framework in which researching institutions andmanufacturers are the main operators from FY2023. Along with these matters, NDF undertakes thefollowing two initiatives to secure cooperation between R&D implementers and TEPCO, as well as
to further strengthen its functions in planning and proposing R&D and ensuring the actual site
applicability of research results. Continual improvement will be made on these initiatives.
⚫

⚫

Request for: Initiative to widely solicit research and development to be addressed
Information (RFI) : in the Project of Decommissioning, Contaminated water and Treatedwater Management and to unearth the seeds of new ideas ofdevelopment (started in fiscal 2022)
Business Review : : Initiative to set appropriate milestones for subsidized projects, thenevaluate the activities of operators in terms of actual machineengineering and actual site applicability at appropriate times, andprovide necessary guidance and advice (to be launched in fiscal 2023)

5.2.3 Promotion of cooperation between decommissioning sites anduniversities/researching institutions
MEXT has been promoting basic/fundamental research and human resource development
activities, which contribute to problem-solving including decommissioning of the Fukushima Daiichi
NPS, in the World Intelligence Project led by JAEA/CLADS targeting universities/researching
institutions.
To deepen the matching between needs and seeds and ensure consistency frombasic/fundamental research to applied practical application research, collaboration has been madebetween the Project of Decommissioning, Contaminated Water and Treated Water Management
and the World Intelligence Project so far. Further collaboration with TEPCO is required to apply the
research results on-site. To further develop decommissioning R&D in the future, NDF and theorganizations concerned should collaborate to actively share information on their respective
projects using the Decommissioning R&D Partnership Council and other opportunities.
In order to make the long-term decommissioning of the Fukushima Daiichi NPS proceed steadierin technical aspects, it is essential to work on developing R&D infrastructure and accumulatetechnological knowledge, develop fundamental technologies and collect basic data, building up
research centers, facilities and equipment, and human resource development. The JAEA, with
JAEA/CLADS as its core, is working to enhance its base functions by conducting research anddevelopment based further on decommissioning needs, and is developing the Naraha Center for
Remote Control Technology Development and the Okuma Analysis and Research Center as
hardware.

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6. Activities to support our technical strategy
6.1 Capabilities, organization, and personnel to proceed with decommissioning
6.1.1 Ensuring the capability, organization and personnel that TEPCO should possess as
the owner of the Fukushima Daiichi Nuclear Power Station
6.1.1.1 Significance and current status of decommissioning project management
In project-type work, such as decommissioning work at the Fukushima Daiichi Nuclear Power
Station, the series of tasks consists of clarifying the objectives (i.e., what to do by when for what),
determining the specific work content as a means to achieve the objectives, checking the safety
and efficiency of the work, designing/manufacturing/building necessary equipment, ensuring thenecessary personnel, and using them to achieve the objectives. Thus, the significance of the project
management is to clarify the objectives, means, required resources and timelines, and then, tosystematically manage project execution in order to accomplish the objectives.
TEPCO has been working to build and strengthen its project management system, which was
reorganized in April 2020. Project-based organization management has been almost establishedthrough three years of operation. Tousou Mirai Technology Co., Ltd. was established to undertakethe basic design required for further expansion of fuel debris retrieval in scale. By seconding its
employees to this company, TEPCO is working to acquire cost and process management
capabilities, risk management capabilities for uncertain elements, and design know-how, whichhave been dependent on manufacturers. Now that it is in phase 3-[1], the decommissioning work
becomes more difficult and uncertain, and in order to smoothly coordinate and align the entire
project with a view to the medium- to long-term, it will be more important than ever that the relevantorganizations will further strengthen a management framework in cooperation with each othertowards the goal to be achieved, and increase the collective strength.
Examples of main initiatives undertaken by TEPCO up to FY2022 include enhancing the authorityof project managers through reorganization, building and operating a risk monitoring system,
improving safety and quality levels, and preparing a forward-looking plan (Mid-and-Long-term
Decommissioning Action Plan).
6.1.1.2 Capability an owner should possess
As stated in the Fourth Special Business Plan, TEPCO should acquire an owner’s engineering
capabilities. Additionally, in view of the peculiarities of the Fukushima Daiichi NPS, there are
required abilities for upgrading the overall decommissioning strategy to advance coexistence ofreconstruction and decommissioning.
In the following paragraphs, the capabilities that should be strategically enhanced by TEPCO in
the future, as NDF believes, are described. Instead of addressing only the issues pointed out,
regarding the capabilities required for all activities from the development of the decommissioning
project strategy and plan to its implementation, TEPCO should consider what should be acquired
in priority among such capabilities and continue taking a proactive approach for the acquisition.

46

(1) Establishment of safety first
perspectives

and engineering based on safety and operator’s

In view of the peculiarities of the Fukushima Daiichi NPS, TEPCO needs to continue instillingthe safety-first approach. Then, it is necessary to establish a process in which operators who arefamiliar with the site should be based on the actual situation of the site, check the safetycomprehensively, determine the appropriate general safety requirements for the site, and workon it. The overall capability required for this purpose, including field capabilities, is engineering
based on safety and operator’s perspectives, and it goes without saying that TEPCO is required
to further enhance this capability.
(2) Investigation capability at the upstream side of the project
In decommissioning work at the Fukushima Daiichi NPS, which does not have the upstream
design concepts and standards, unlike conventional nuclear power plants, the cases have been
accepted, where the project is allowed to return to the process that reexamines what functions
should be achieved and what general safety requirements need to be satisfied for that after the
project is launched and proceeded with.
In the future, TEPCO should clarify the significance and objectives of the project (what to doby when and for what), specify general safety requirements, develop a comprehensive wasterelated plan covering its generation control, reuse, etc., and ensure the feasibility of the project.
To this end, in the decommissioning process from its planning to implementation, enhancing theinvestigation capability is needed, especially at the upstream side.
However, due to the extremely high uncertainty particular to decommissioning at the
Fukushima Daiichi NPS, it should also be noted that even if the investigation at the upstreamside is enhanced, it does not necessarily mean that everything will proceed according to theresult of the investigation. TEPCO, based on the assumption that iteration-based engineering isinevitable to some degree in the future, should aim to optimize its research capability in the
upstream of the project by adding the latest knowledge from research and development.
(3) Capability to upgrade project management
Larger, more complex, and highly uncertain high-difficulty projects are expected in the future,and in such situations, it will be difficult for TEPCO to proceed with work only by simple buying(buying), which is to say, by just deciding specifications, prices, and schedules, and procuring
goods and services. To adapt to this situation, TEPCO should upgrade its project management,
including the relationship with the contractor and the manner of the contract in the case of making
a new product (making).
(4) Nuclear security management capability
With regard to improvement actions in response to the physical protection incidents that
occurred at the Kashiwazaki-Kariwa, although the situation is different from that of the Fukushima

47

Daiichi NPS in many ways, it is necessary to ensure that the same measures are taken to the
aspects in common to make improvements.
NDF will continue to pay close attention to TEPCO’s efforts to enhance its nuclear security
management capabilities.
6.1.1.3 Initiatives related to organization
In order for TEPCO to further promote “coexistence of reconstruction and decommissioning”, allemployees, both inside and outside the Fukushima Daiichi NPS, must share the same aspirations
and sense of responsibility regarding how TEPCO can contribute to this region, and must do theirbest to transcend organizational barriers.
In order to achieve this, TEPCO decided to consider integrating and reorganizing the head officeof Fukushima Daini NPS, which currently belong to the Nuclear Power and Site Headquarters, into
Fukushima Daiichi Decontamination and Decommissioning Engineering Company, and in July thisyear, the Office of Organizational Restructuring Preparation was established as the umbrellaorganization for this. NDF also regards these TEPCO efforts positively, and intends to confirm theactivities so that TEPCO will step up progress to achieve coexistence of reconstruction anddecommissioning as the integration and reorganization advance.
6.1.1.4 Initiatives to recruit and develop personnel(1) Short-term efforts
The decommissioning work at the Fukushima Daiichi NPS is at the phase of starting the mostcritical milestone in recent years, the trial retrieval of fuel debris. To be in line with the gradualexpansion of fuel debris retrieval, the entire workload of the plant is also increasing.
Although TEPCO is actively recruiting to meet such strong demand for personnel on-site, in
addition to that, it is essential that its leaders clarify work priorities and promote resources
allocation according to the priorities, and development of human resources should be promoted
to enhance versatility and productivity of existing personnel. TEPCO has been conducting kaizen
activities for a long time, and it is an initiative that incorporates the methods of Toyota’s
kaizen/continuous improvement method with the aim of improving quality and safety. As this isalso useful for solving secondary resource issues, the activities should be continued vigorously.
Other than that, it is also indispensable to provide education and training, conduct digitaltransformation (DX), and obtain the necessary outputs with limited resources through efforts.
(2) Medium- and long-term initiatives
The integration of the Fukushima Daiichi Decontamination and Decommissioning Engineering
Company and the Fukushima Daini NPS, which TEPCO has been working on, is also crucial in
the sense that it aims to optimize the use of personnel beyond the boundaries of business sites
through organizational restructuring. The consolidation should be accompanied by thediversification of personnel, standardization and streamlining of business operations, and efforts
to ensure the necessary personnel.

48

In decommissioning work where the workloads are expected to increase from now on, it will
require personnel for ever-changing project-based work as well as personnel for operation andmaintenance of the new facilities that will be installed as a result of the execution of projects. To
ensure such personnel, TEPCO itself should determine what type of and when personnel will beneeded in the medium- to long-term, and clearly present the necessity at an early stage so thatthe company can carry out the activities to recruit personnel from inside and outside the company
widely through various channels. This is necessary for hiring, reskilling employees with a view tothe medium- to long-term, personnel management including attractive career path design foryoung employees, enhancing the understanding of the community, and making up for personnel
shortages through collaboration with external organizations.
In view of the fact that decommissioning is a long-term activity, TEPCO needs to work tocultivate leaders who will be responsible for decommissioning in a planned and systematicmanner from a medium- to long-term standpoint. It is undeniable that leaders in charge of
unprecedented and difficult decommissioning projects require a higher level of courage andpeople skills compared to other projects, in particular. In addition, they need to possess a keensense of perception that anticipates the changing business environment as well as the ability toadapt to change, and the ability to learn. Furthermore, if other people in the organization are
influenced by the leaders who are working on decommissioning as a national challenge as well
as by the leadership group following those leaders, and become aware of their own potential andmotivated to grow, this will also lead to the recruitment and development of decommissioning
personnel over the medium to long-term.
6.1.2 Fostering the next generation responsible for the decommissioning and promoting
public understanding(1) Fostering the next generation who will be responsible for the future decommissioningof Fukushima Daiichi NPS
In order to continue decommissioning of the Fukushima Daiichi NPS over a long period and tocontinue the R&D activities necessary to that end, it is essential to train and secure future
researchers and engineers and to ensure the inheritance of technological skills. It is necessary
for industrial-academic-governmental institutions overall to move steadily ahead with efforts
according to each level of the secondary and higher education stages.
In decommissioning the Fukushima Daiichi NPS, it is necessary to recruit and develop
personnel with expertise in nuclear power as well as personnel specialized in science andtechnology in other fields. The challenge is how to continuously open up opportunities forpromoting excellent personnel with expertise in various fields. In order to achieve this, it isnecessary for higher and secondary educational institutions to create opportunities for learningand acquiring peripheral knowledge in addition to expertise, and to maintain associated systems
and structures so that they can function as a whole, including teachers. For this reason, the WorldIntelligence Project has introduced a mechanism for students and young researchers to engage49

in decommissioning research. Further, to students in secondary education, it is important thatefforts are made to ensure that involvement in the nuclear power field, including thedecommissioning, will appeal to them.
(2) Dissemination of basic knowledge and promoting people's understanding ofdecommissioning and the radiation safety involved in decommissioning
Acquiring a basic knowledge of the Fukushima Daiichi NPS is fundamental to promoting public
understanding of decommissioning. In particular, from the perspective of enhancing resilience tovarious disasters in the future, the challenge is to ensure that children, who are the pillar of the
future, have opportunities to learn according to their developmental stage. For this reason, thegovernment has been promoting the continuation and expansion of on-site classes and the useof radiological supplementary readers.

6.2 Strengthening international cooperation
6.2.1 Significance and the current status of international cooperation
In order to steadily proceed with the decommissioning of the Fukushima Daiichi NPS, which
deals with highly difficult engineering issues, it is important to utilize the experience gained throughpreceding decommissioning activities of past nuclear facilities (hereinafter referred to as "legacy
site".) located overseas. Therefore, it is necessary to promote bilateral cooperation in line with thecircumstances of each country and to incorporate the experience of decommissioning activities
around the world by utilizing the framework of multilateral cooperation through internationalorganizations such as the IAEA and the OECD/NEA. These international organizations play animportant role in developing international standards for decommissioning, and Japan's participationin such efforts is meaningful in promoting the decommissioning of Fukushima Daiichi NPS in an
open manner to the international community. In addition, Japan is expected to fulfill part of its
responsibility to the international community by sharing the experiences gained through thedecommissioning with other countries. From these perspectives, Japan has been making efforts tostrengthen international cooperation by concluding cooperation agreements with relevant overseasorganizations. It is important to gain international understanding as our country moves forward withthe decommissioning of Fukushima Daiichi NPS. To this end, in addition to gathering of wisdomand sharing of experience, it is necessary to disseminate transparent information to theinternational community and to engage in continuous dialogue.
The Japanese government, TEPCO, and NDF are each working with their counterparts to sharetechnical cooperation, information, experience, lessons learned, etc., with the aim of building astrong cooperative relationship for long-term decommissioning in the future. Moreover, from theviewpoint of maintaining a foundation for utilizing and collecting the knowledge of experts fromaround the world, NDF annually holds the International Forum on the Decommissioning of the
Fukushima Daiichi NPS (hereinafter referred to as the “International Forum”), continuously
disseminates information on the current status of and issues related to decommissioning.

50

6.2.2 Key issues and strategies(1) Integrating and giving back the wisdom and knowledge from around the world
To ensure the decommissioning of Fukushima Daiichi NPS, it is necessary to learn lessons
from the decommissioning activity examples of experienced legacy sites and apply them todecommissioning, and to utilize world-class technologies and human resources, in other words,
to mobilize and utilize the world's wisdom. TEPCO has stationed staff at legacy sites to obtain
technical knowledge of decommissioning and operational know-how through practicalexperience, and regularly conducts visits of legacy sites and information exchanges withdecommissioning-related organizations and companies. NDF is committed to bringing together
the wisdom of the world through regular exchange of information with the public
decommissioning implementation entities with a central role in each country. Japan has received
a variety of support from overseas through the dissemination of information to the international
community, participation in international joint activities, etc. It is necessary to continue to gather
world wisdom in technical and operational aspects. Therefore, it is expected that thedecommissioning will be undertaken with the following three strategies into consideration.
① Strengthening cooperation with counterparts
TEPCO, as an entity that implements decommissioning steadily, and NDF, as anorganization that provides advice and guidance to ensure proper and steady implementationof decommissioning from a mid-to-long-term perspective, will maintain a high level ofrelationship with their respective counterparts and continue to regularly exchange information,
which will be reflected and utilized to the maximum extent possible to solve the required issues.
② Expanding the scope of information collection
It is desirable to explore the possibility of applying general-purpose technologies from morecountries to decommissioning and collect technical information, including countries that do not
use nuclear technology.
③ Return of results
The project will continue these mutually beneficial relationships while being conscious of
returning the expertise and results accumulated domestically so far to the international
community. It is also effective to maintain interest in decommissioning technology by
responding not only to accidents or decommissioning, but also to aspects such as applications
to issues other than nuclear power.
(2) Maintaining and developing the international community’s understanding, interest andcooperation in decommissioning
The challenge is to maintain and develop the international community’s understanding, interest
and cooperation in order to bring together the world’s wisdom in the decommissioning ofFukushima Daiichi NPS and to limit the risk of confrontational structures to the implementationof decommissioning as far as possible.

51

International opinion can considerably impact the progress and success of decommissioning.
Therefore, it is necessary to define a policy for international cooperation, taking into account the
impact that the spread of misperceptions regarding the decommissioning of the Fukushima
Daiichi NPS overseas affects the decommissioning progress. The strategy for gaining
international understanding needs to be divided into ① an approach for experts and ② anapproach for the general public.
①

Approach to experts
It is fundamental for the international community to understand that the efforts toward thedecommissioning of the Fukushima Daiichi NPS are scientifically and technically valid andaccurately understood by experts abroad. Approximately 12 years have passed since theaccident, and there are signs of a decline in international interest in decommissioning
technology and progress, as seen in the decreasing number of papers on decommissioning of
the Fukushima Daiichi NPS presented at recent international conferences. In order to maintaininterest outside Japan, dialogue and exchange with foreign counterparts should be activatedoutside Japan among technology implementers, technology developers, and researchers
involved in the practical implementation of the technology, beyond the public and private
sectors.
Until now, based on the framework for cooperation in decommissioning technology,
information has been disseminated and exchanged mainly with advanced nuclear power
countries that own legacy sites. These activities are significant in complementing theinternational publicity and are important in gaining international understanding in that they candirectly communicate the latest technical information to foreign experts. Furthermore, withregard to unprecedented efforts being made in a peculiar environment of the Fukushima
Daiichi NPS, such as fuel debris retrieval and waste management, it is also important toincorporate opinions from new perspectives as well as gain an accurate understanding of theefforts being made through dialogue with many experts from neighboring countries andcountries that do not use nuclear technology. It is also expected that the understanding ofthese experts can be used as a springboard for the spread of correct understanding in theircountries. Japan should also support socially influential experts to speak out based on correctknowledge in their own countries and ultimately have a positive impact on international public
opinion.
In order to contribute to the formation of international public opinion based on scientific andaccurate information, the world's experts must first be correctly understood. Recognizing this,Japan should work also with national government agencies and international organizations todisseminate information and engage in ongoing dialogue with relevant parties on theachievements of its efforts towards decommissioning.

52

② Approaches to the general public
The interests of the recipients of the information have changed since the time of the accident,
and there are some gaps between countries in the amount of knowledge and information thatare the basis of understanding. Moreover, it is desirable for Japan to actively provide
information on the accident at the Fukushima Daiichi NPS, and activities and achievements
toward decommissioning to countries other than advanced nuclear nations in cooperation withinternational organizations.
Regarding the discharge of ALPS-treated water into the sea, the Ministry of Foreign Affairsof Japan (MOFA) and the Ministry of Economy, Trade and Industry (METI) are taking the leadin actively publicizing the issue, based on scientific perspectives. In addition, the Japanese
government has implemented concerted measures, such as responding to IAEA reviews by
METI and the NRA.
It is difficult to proceed with the decommissioning of the Fukushima Daiichi NPS without
global understanding. We will endeavor to build trust by actively and strategically returning to
the international community the knowledge, etc. obtained in the course of conducting researchon the accident at the Fukushima Daiichi NPS and the decommissioning of the plant.
Furthermore, as a responsibility of Japan, which caused the accident, the government andother domestic organizations concerned must continue to provide highly transparent andaccurate information on decommissioning of nuclear power stations, which should be
strategically addressed in the future.

6.3 Local community engagement
6.3.1 Significance and the current status of local community engagement
The fundamental principle for the decommissioning of the Fukushima Daiichi NPS is“coexistence of reconstruction and decommission”. While progress in reconstruction is being madegradually, decommissioning should never become an obstacle to the reconstruction process. It is
important to sincerely listen to local residents’ concerns and questions, and to deepen theirunderstanding and reassure them about the decommissioning process through two-way
communication. To this end, the government is exchanging views with concerned localorganizations at The Fukushima Advisory Board on Decommissioning, Contaminated Water andTreated Water, and other organized meetings; disseminating information through videos, websites,
brochures, and other media summarizing the current status of decommissioning; and holding
information meetings and roundtable discussions for local residents and relevant local
governments. NDF also holds international forums where local residents and other participants
exchange frank opinions on decommissioning with related organizations. TEPCO actively
disseminates information utilizing its website and brochures, and accepts visitors to the Fukushima
Daiichi NPS.
In order to carry through the decommissioning of the plant over a long period of time, thecontinued cooperation of local and other companies is essential. Moreover, inviting local

53

companies to participate in the decommissioning project and revitalizing decommissioning-relatedindustries in this region will be an important pillar in contributing to Fukushima’s reconstruction.
Therefore, based on the “Commitment to the people of Fukushima to achieve both reconstruction
and decommissioning” formulated at the end of March 2020, TEPCO has organized its initiatives
for the industrial cluster for decommissioning into three major categories: (1) increasing
participation of local companies, (2) supporting local companies to step up, and (3) creating new
industries locally, and phased in the initiatives. With regard to (1) and (2), TEPCO has promoted
these initiatives in cooperation with the Fukushima Innovation Coast Framework Promotion
Organization and the Fukushima Sousou Reconstruction Promotion Organization, and fromFY2022, has provided information to help local companies consider participation by clearly indicate
more specific tasks that are candidates for participation by those companies in the “Medium-toLong-term Ordering Outlook in the Decommissioning” prepared since September 2020. This
information is provided. With regard to (3), in order to build a system for integrated implementationof decommissioning projects locally in the 2020s, “Tousou Mirai Manufacturing Corporation” toestablish a plant to manufacture core products necessary for decommissioning, and “Tousou Mirai
Technology Co. Ltd.” to conduct basic design necessary to further expand of fuel debris retrieval
in scale in October 2022.
6.3.2 Key issues and strategies(1) Communication issues and strategies
Since misunderstandings, concerns, and rumors caused by inappropriate dissemination of
information regarding decommissioning will not only delay decommissioning but also hinder thereconstruction of Fukushima, TEPCO will continue to face the issue of communicating the current
status of decommissioning in a timely and easy-to-understand manner. Therefore, along withefforts involving direct participation such as face-to-face meetings and inspection tours, TEPCO
will strengthen communication that can be conducted in a non-face-to-face and non-contact
manner.
Another issue will be to ensure that the government, NDF, and TEPCO work together
appropriately, provide information more carefully, and work to build trust with the community. For
this purpose, while proactively working in cooperation with related organizations, accurate
information should be provided in an easy-to-understand and courteous manner bycommunicating in both directions through dialogue. In particular, with regard to the disposal of
ALPS-treated water, the government and TEPCO are taking measures to disseminate
information and suppress reputational impact, as dissemination of accurate information andmeasures against reputational damages will continue to be issues.
(2) Issues and strategies related to the creation of a regional industrial and economic basethrough decommissioning
As the initiative for “(3) creating new industries locally” is relatively large-scale investment, and
it is required to steadily promote and strengthen the initiative. On the other hand, since54manufacture of highly-functional products requires advanced technology, the issue is whether
this will lead to the active participation of local companies. For the time being, the current
initiatives including “(1) increasing participation of local companies” and “(2) supporting local
companies to step up” should be continued and strengthened, while carefully explaining the study
status of new decommissioning-related facilities to the local governments, commercial andindustrial organizations, etc., to gain their understanding and cooperation. Furthermore, with thecooperation of prime contractors, it is also necessary to consider and implement on a trial basis
various approaches, including ordering and contracting, that will make it easier for local
companies to receive orders. Moreover, by clearly indicating candidate tasks for participation by
local companies in the “Medium-and-Long-Term Ordering Outlook of Decommissioning” in
FY2022, it is important to continue to conduct initiatives to increase participation. It is therefore
necessary to continue to promote initiatives to facilitate participation by local companies andinitiatives that enable local companies to continue to foresee orders of a certain size.
To steadily promote efforts of coexistence with local community, TEPCO needs to further
strengthen its partnership and collaboration with local governments and relevant localorganizations, along with close internal cooperation. NDF will support TEPCO's efforts topromote regional coexistence, and will work to strengthen coordination and collaboration withlocal governments and relevant local organizations.

55