Technical Strategic Plan 2018
for Decommissioning of the Fukushima Daiichi
Nuclear Power Station ofTokyo Electric Power Company Holdings, Inc.

Overview

November, 2018

Nuclear Damage Compensation and Decommissioning
Facilitation Corporation
NDF

Table of contents
Introduction ............................................................................................................................... 1

1
1)

Enhancement of structure and system toward appropriate and steady implementation of
decommissioning ............................................................................................................... 1

2)

Strategic Plan..................................................................................................................... 2
Decommissioning of the Fukushima Daiichi NPS as risk reduction strategies ........................ 3

2
1)

Basic concept of the decommissioning of the Fukushima Daiichi NPS ............................ 3

2)

Progress status of the decommissioning of the Fukushima Daiichi NPS ......................... 3

3)

Basic concept of reducing risk of radioactive materials .................................................... 5
Technological strategies toward decommissioning of the Fukushima Daiichi NPS .............. 10

3
1)

Fuel debris retrieval ......................................................................................................... 10

2)

Waste management ......................................................................................................... 24

3)

Contaminated water management .................................................................................. 29

4)

Fuel removal from spent fuel pools ................................................................................. 32

5)

Other specific measures .................................................................................................. 36

6)

Comprehensive efforts for the decommissioning project of the Fukushima Daiichi NPS 38
Handling critical enablers for smooth operation of the project ............................................... 40

4
1)

Actions toward improvement of working environment and conditions ............................ 40

2)

Concept of securing safety and promotion of cooperation .............................................. 40

3)

Enforced management structure for steady mid-and-long-term decommissioning ........ 40

4)

Developing and securing human resources .................................................................... 40
R&D initiatives ......................................................................................................................... 42

5
1)

Basic policy for R&D ........................................................................................................ 42

2)

R&D of decommissioning required for on-site work/engineering .................................... 44

3)

Enhancement of basic study and R&D infrastructure for the success of thedecommissioning project ................................................................................................. 44
Enhancement of international cooperation ............................................................................. 46

6
1)

Significance of international cooperation ......................................................................... 46

2)

Facilitation of international cooperation activities ............................................................ 47i.

Enhancement of partnership with overseas decommissioning agency .......................... 47ii.

Integrating and utilizing wisdom and knowledge from around the world ........................ 47

iii.

Dissemination to global society ....................................................................................... 47

3)

Close cooperation with relevant domestic organizations ................................................ 48

7

Local community engagement and further enhancement of communication ........................ 49
1)

Approaches for local community engagement and further enhancement ofcommunication................................................................................................................. 49

2)

Actual effort for better communication ............................................................................. 49

3)

Further spread of communication and measures to reputational damages.................... 50

1 Introduction
Since 2015, the Nuclear Damage Compensation and Decommissioning Facilitation Corporation(hereinafter referred to as the “NDF”) has annually developed the “Technical Strategic Plan for
Decommissioning of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power
Company Holdings, Inc.” (hereinafter referred to as the “Strategic Plan”). The purpose of thisdevelopment is to provide a technical basis for contributing to the implementation and revision of
the Government-developed “Mid-and-Long-Term Roadmap towards the Decommissioning of
TEPCO’s Fukushima Daiichi Nuclear Power Station” (hereinafter referred to as the “Roadmap”).

1) Enhancement of structure and system toward appropriate and steady
implementation of decommissioning
Seven years have passed since the accident at the Fukushima Daiichi NPS. In this period, it has
made some progress in various activities such as building land-side impermeable wall as a part ofcontaminated water management, removing spent fuel from the spent fuel pool, and improving
work environment in the site. Moreover, from a mid-and-long-term perspective, study and R&D
activities toward both fuel debris retrieval work and waste management have progressed.
Additionally, Roadmap was revised, policy on fuel debris retrieval was determined, and basic
policies on the solid waste was developed.
As the phase of decommissioning moves, Tokyo Electric Power Company Holdings, Inc.
(hereinafter referred to as “TEPCO”) has been enforcing project management structure, to handle
mid-and-long-term issues systematically, with steadily addressing present issues. In addition, tomore steadily ensure decommissioning in terms of funding, an amendment of the NDF Act was
passed in May 2017 and enforced in October 2017. Based on this Act, NDF has increased
responsibility for management of reserve fund for decommissioning (hereinafter referred to as
Reserve Fund). In this responsibility, in every fiscal year, it was determined that 1. TEPCO deposits
the amount required by NDF to implement decommissioning appropriately and steadily as well as
approved by competent minister (Minister of Economy, Trade and Industry), 2. Based on the“Withdrawal plan for reserve fund” (hereinafter referred to as “Withdrawal plan”), jointly preparedby NDF and TEPCO and approved by competent minister, TEPCO will withdraw reserve fund andimplement decommissioning. (Fig. 1)
Under the system of the reserve fund, NDF will 1) appropriately manage the fund fordecommissioning, 2) manage the implementation structure of decommissioning properly and 3)
manage the decommissioning work appropriately and NDF increased responsibility now as anorganization to manage and oversee TEPCO’s decommissioning activities. In particular, based on“The Policy for Preparation of Withdrawal Plan for Reserve Fund for Decommissioning” (hereinafterreferred to as “The Policy for Preparation of Withdrawal Plan”), NDF will propose work target andmain works to be included in the Withdrawal Plan. In addition, NDF will assess the validity of
TEPCO’s performance from the standpoint of project accomplishment, considering engagement
and communications with local communities in the process of joint creation of Withdrawal Plan withTEPCO. Through these proposal and assessment, NDF supports an appropriate and steady
implementation of decommissioning.

1

Nuclear Emergency Response Headquarters (Director: Prime Minister)Council for the Decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station

Nuclear Regulation Authority(Chairperson: Chief Cabinet Secretary) Approval of implementation
plan, pre-service inspection,
welding inspection, etc.

Mid-and-Long-Term Roadmap

The Team for Countermeasures for Decommissioning and Contaminated Water Treatment(Head of Team: Minister of Economy, Trade and Industry)

Progressmanagement

Granting of
project budget

R&D organization

Apply forapproval

Approve

Nuclear Damage Compensation and Decommissioning Facilitation Corporation

 Development of a mid-to-long-term strategy
Withdrawal plan Tech. support for progress mgmt of important issues (in collaboration)
 R&D planning and progress management
Strategic  Strengthen international partnershipReserve Fund forplan  Management of Reserve Fund for
Decommissioning
Decommissioning

International Research Institute for
Nuclear Decommissioning (IRID)*
Share progress
Japan Atomic Energy Agency (JAEA), and challengesetc.
 R&D implementation
ReportAdvice, guidance, recommendations,supervision and support
Reserverelated to project management, etc.

Monitoring, examination

ReportReport on theoutcome

Minister of Economy, Trade and Industry

Presentation ofimportant issues

Apply for report Progress management of each countermeasure according toMid-and-Long-Term Roadmap

ReportBidirectional dialogue

Local residents and communities

Organizations related to decommissioning Decide the direction of decommissioning and contaminated water
treatment

Disburse-mentTokyo Electric Power Company Holdings, Inc. (Fukushima Daiichi Decontamination and Decommissioning Engineering Company)
 Contaminated water management, fuel removal from spent fuel pools, fuel debris retrieval, waste disposal,
improvement of power plant premises and working environment, management of Units 5 and 6, etc.
 Through TEPCO's management reform, the funds required for decommissioning should be reserved
responsibly (Implementation of new comprehensive special project plan)

Implementation
plan* TEPCO, a decommissioning project operator, participates as a member of IRID and shares the needs, challenges, and results of research and development.

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

2) Strategic Plan
In the previous Strategic Plans, fuel debris retrieval and waste management have been focusedas the mid-and-long-term decommissioning strategies that NDF should address, and thosemeasures have been considered. However, in elaborating fuel debris retrieval work, it will benecessary to consider not only these issues but also the relationship and consistency withmeasures for contaminated water and fuel removal from the spent fuel pools. Therefore, theStrategic Plan should also include measures for contaminated water and fuel removal from thespent fuel pools and present the mid-and-long-term direction, overlooking total approach fordecommissioning of the Fukushima Daiichi NPS. The issues extracted from these considerations
as items to address for the near term, will be reflected on the Policy for Preparation of Withdrawal
Plan, which NDF will propose to TEPCO (Fig.2).

Fig. 2 Positioning of the Strategic Plan based on the system of the Reserve Fund2

2 Decommissioning of the Fukushima Daiichi NPS as risk
reduction strategies
1) Basic concept of the decommissioning of the Fukushima Daiichi NPS
Concerning to the Fukushima Daiichi NPS decommissioning, the basic concept is to continuously
and quickly reduce the radioactive risk caused by the accident that does not exist in the usual NPS.

2) Progress status of the decommissioning of the Fukushima Daiichi NPS
The Fukushima Daiichi NPS has the necessary safety measures in place that are required by
the NRA in “the matters for which measures should be taken” (hereinafter referred to as “Mattersto be addressed”) and is maintained in a state with a certain level of stability. In addition, as a resultof various risk reduction measures taken so far, risk reduction has been continuously achieved asfollows:(1) Contaminated water management
Measures have been taken based on the three principles on the issue of contaminated water(“Removing” contamination sources, “Redirecting” fresh water from contamination sources, and“Retaining” contaminated water from leakage).
As a measure of “Removing” contamination source, radioactive materials are removed fromcontaminated water with multi-nuclide removal equipment. As a measure of “Redirecting” fresh
water from contaminated sources, freezing operation of all the areas of the land-side
impermeable walls started by August 2017. In March 2018, the installation completed except
for deep areas. Consequently, the completion of the land-side impermeable wall and reinforceof the sub-drain system led to the decrease of the groundwater inflow into the buildings. Totalamount of the contaminated water attributed to rainwater and groundwater decreased due todecreased inflow into the buildings and sharp decrease in the amount of the water transferredfrom the groundwater-drains to the buildings. In addition, the effect of the land-side impermeable
wall appeared in the decreased pumping amount both in the sub-drains and groundwater drains.
As a result of “Retaining” contaminated water from leakage, the concentration of radioactive
materials in the surrounding sea area is constantly low.
In treating stagnant water in the buildings, the amount of stored water has been decreasing
steadily by lowering water level within turbine buildings with the goal of completing the treatment
in 2020. The level of stagnant water in the Unit 1 Turbine Building was reduced to the lowest
floor level in March 2017. In the Unit 2 - 4 turbine buildings, the level of the stagnant water
lowered to the lowest floor’s intermediate ceiling, which was exposed in December 2017. For
the condensers of Unit 1 – 3, where the highly radioactive stagnant water was stored at the timeof accident, draining completed by December 2017 and so forth, thereby radioactive substances
contained in the stagnant water sharply decreased. A new circulation system for thecontaminated water management started the operation in February 2018 to reduce theconcentration of the radioactive materials in the stagnant water. Decreasing both the amount of3

the stagnant water and the concentration of the radioactive materials accelerate the reductionof the inventory of the radioactive materials in the stagnant water.
Moreover, the water treated by the multi-nuclide removal equipment is stored in the welded
type tanks, so that the risk is managed in sufficiently low level. Comprehensive discussion
including social standpoints such as mitigation of reputational damages have been made in thegovernment’s subcommittee on the water treated by the multi-nuclide removal equipment.
(2) Fuel removal from spent fuel pools
In Unit 1, to remove fuel from spent fuel pools at the operating floor, rubble removal in thenorth of the operating floor was started in January 2018.
In Unit 2, as a part of preparation of fuel removal from spent fuel pool, opening to provide
access to the operating floor was made, then investigation on dose or contamination in theoperation floor was started by using robots and heavy machinery in July, 2018 (scheduled in
November 2018).
In Unit 3, a cover for fuel removal from the pool was installed in February 2018. Once started
the trial operation for fuel handling equipment, several troubles have occurred. TEPCO is
examining and reviewing the start of fuel removal in the spent fuel pool which was scheduled in
November 2018.
(3) Fuel debris retrieval
In Unit 2, internal investigation of Primary Containment Vessel (hereinafter referred to as the“PCV”) was conducted in January 2018, continued from January and February 2017. It was
confirmed that deposits, which seemed to be fuel debris, are accumulated in the bottom ofpedestal, according to the result of analysis of the images obtained.
In Unit 3, based on results of investigation in July 2017 using a remotely operated underwater
survey vehicle (ROV), three D shape reconstruction was conducted, to grasp whole image
within the pedestal. It was found out that swivel platform came off the track, and partly buried in
the deposit, showing relative position of structures.
(4) Waste management
In February 2018, operation of solid waste storage building No. 9, which has about 40% ofstorage capacity of the existing solid waste storages (buildings No.1 – 8), was started. In thestorage facility with shielding function, it became possible to store the highly radioactive rubbles
arisen from removal in the operating floor of Unit 1 and dismantling of upper part of reactor
building of Unit 2. In addition, sampling and analysis has been progressing for the purpose ofcharacterization. Storage management plan was revised in June 2018 based on the results ofrevision of prediction of generation of solid waste.
(5) Other specific measures
The surrounding road of Unit 1 to 4 buildings and part of east side of turbine buildings were
determined as “ordinary clothing area”, where the workers are allowed to enter and work ingeneral workwear or in on-site safety workwear with disposable dust-proof mask. By this,ordinary clothing area expanded to approximately 96% of the Fukushima Daiichi NPS site.

43) Basic concept of reducing risk of radioactive materialsi.

Quantitative grasping of risk
In the Strategic Plan, the method based on the Safety and Environmental Detriment score(hereinafter referred to as “SED”) developed by Nuclear Decommissioning Authority (hereinafterreferred to as “NDA”) is used to express the magnitude of risk (risk level) of radioactive materials.
In this method, risk level is expressed as the product of “Hazard Potential”, which is used to indicate
the level of impact of internal exposure caused by intake of radioactive substance into the human
body, and “Safety Management” which is used as an index to indicate the likelihood of occurrenceof the event.
ii.

Identification of risk source and risk assessment
The major risk sources of the Fukushima Daiichi NPS are indicated in Table 1. Moreover, therisk levels of each risk source expressed using Hazard Potential and Safety Management are
shown in Fig. 3.
In the Roadmap, management of these risk sources is classified into the three broad categories:
1. Highly contaminated water and fuels in the spent fuel pools, etc., relatively high risks given highpriority, 2. Fuel debris, etc., immediate risks unlikely, risks may grow if neglected, 3. Solid waste,etc. increased risk unlikely in the future, but appropriate decommissioning efforts necessary. Theirpriorities are set, and appropriate measures are proceeded. Risk reduction strategies for each ofthese sources will be described in Section 3.

5

Table 1 Major risk sources in the current risk map
Fuel debris
Spent fuel

Fuel debris in the RPVs/PCVs in Units 1-3
Fuel in SFPs

Fuel assemblies stored in the spent fuel pools (SFPs) in
Units 1-3

Fuel in the common

Fuel assemblies stored in the common pool

pool
Fuel in dry casks

Fuel assemblies stored in dry casks

Contaminated Stagnant waterContaminated water accumulated in the reactor

water etc.

buildings and turbine buildings in Units 1-4, mainin the buildings

process building, and high temperature incinerator
building.
Stored water

Strontium-treated water, residual concentrated salt

in flanged tanks

waterStored water

Strontium-treated water, treated water by ALPSin welded tanks
Secondary

Waste adsorption

Storing adsorbent used in the cesium adsorption

waste fromcolumns

apparatus, the second cesium adsorption apparatus,

water

high-performance ALPS, mobile-type strontium removal

treatment

equipment, second mobile-type strontium removal

systems

equipment and mobile-type treatment equipment, etc.
HIC slurry

Slurry produced during the treatment by the multinuclide removal equipment stored in high integrity
containers (HIC)

Waste sludge

Precipitation from the decontamination instruments

Concentrated liquid

Concentrated liquid waste generated by evaporative

waste, etc.

concentration of concentrated salt water and carbonate
slurry collected from concentrated liquid waste

Rubble,Solid waste storage

Rubble with high-dose (30mSv/h and above) stored in

etc.

facility

the solid waste storage facility

Soil covered temporary

Rubble stored in Soil covered temporary storage facility,

storage, etc.

Temporary storage tent and Outdoor container storage(1～30mSv/h）, and Felled tree stored in Temporarystorage pool

Outdoor storage, etc.

Rubble stored in Outdoor seat covered storage (0.1～
1mSv/h), Rubble stored in Outdoor storage (Under
0.1mSv/h), and Felled tree stored in Outdoor storage

Contaminated structures, etc. in the

Structures, pipes, components, and other items insidebuildings

the reactor buildings, PCVs or RPVs that arecontaminated with radioactive materials dispersed dueto the accident; and activated materials from operation
before the accident

6

Hazard Potential (logarithmic scale)

Region of sufficiently
stable management(March, 2018)

Fuels incommonpool

Fuel debris

ContaminatedUnit 1structures in bldgs. Unit 3
Unit 2
Fuels in
HIC
Unit 3
SFPs
Waste
slurry Uint 2
Unit 1absorption
columns
Waste
Stagnant water
Concentrated sludgein bldgs.
liquid waste, etc.

Fuels indry casks

Stored water inwelded tanks

Rubble instoragefacility

Stored water inflanged tanks

Soil covered
temporarystorage, etc.
Outdoorstorage, etc.

Safety Management (logarithmic scale)Fig.3 Example of risk levels assigned to the risk sources at the Fukushima Daiichi NPS
iii. Approach to risk reduction strategies and future direction
Interim goal of risk reduction strategies
Risk reduction strategies include reduction in Hazard Potential and Safety Management in
the SED. The examples of reduction in Hazard Potential include decrease in inventory anddecay heat associated with radioactive decay, and changing the form of liquid and gas into theform that is hard to move. To process contaminated water to change into the secondary waste
is an example of form change.
The examples of reduction in Safety Management include transfer of fuel in the pools to thecommon pool, and placement of rubbles stored outside to the storage. Of the various risk
reduction measures, the reduction in Safety Management is considered generally to be easily
achieved. Therefore, the interim goal of risk reduction strategies is to bring the risk levels into
the “Region of sufficiently stable management” (pale blue area) indicated in Fig. 3.
Basic approach to risk reduction
The decommissioning of the Fukushima Daiichi NPS is a project with inherent considerable
uncertainty. To date, internal status of the Unit 1 to 3 is estimated to some extent by simulationof the development process of accident, estimation of location of fuel debris by measurementof muon, projection of inspection equipment into PCV, dose measurement in the buildings andothers. However, to eliminate uncertainty, many resources, especially a considerably long time,
are required. To realize prompt risk reduction, it is necessary to make integrated decisions

7

taking flexible and prompt approach, based on the directions determined with previously
obtained experience and knowledge and with experiment- and analysis-based simulation,
placing safety at the top priority, even though a certain extent of uncertainty remains. At thistime, it is important to flexibly address the issues with experiences, reflecting the internal
information, technical feasibility and other information obtained in advance in a certain Unit on
the subsequent works and the works in other Units. As the viewpoint to make integrated
decisions like this, NDF summarizes the following five guiding principles.
(Five guiding principles)

Safe

Reduction of risks posed by radioactive materials and ensuring worksafety

ProvenHighly reliable and flexible technologies



Efficient

Effective utilization of resources (e.g. human, physical, financial andspace)

TimelyAwareness of time axis



Field-oriented

Thorough application of Three Actuals (actual field, actual things andactual situation)

These guiding principle are the viewpoint necessary to discuss priority of approaches andtotal optimization.
Order of priority
It is important to be aware of position of each project and their mutual relationship in theirrespective fields in managing progress of overall project based on the five guiding principles. In
the decommissioning of the Fukushima Daiichi NPS that aspires to a continuous and prompt
risk reducing, it is important to aim at choosing the best option among the various possible
options, with the integrated viewpoint of looking at the entire site on a long-term basis andconsidering time axis. Taking into account such point of view, TEPCO and NDF have justintroduced project management mechanism.
Addressing temporary increase of risk level associated with the decommissioning
operations.
The implementation of the decommissioning work is striving for prompt risk reduction fromthe mid-and-long-term viewpoint. However, it requires careful consideration of the possibilities
that the performance of decommissioning work may temporarily change the risk levels and may
increase the radiation exposure of workers. This possibility of a temporary increase in the risk
level and a rise in workers’ exposure arising from the decommissioning work must be addressedby ensuring measures to prevent and restrict them. It is imperative to limit the increase in therisk level during the decommissioning work within the permissible range by thoroughpreparations for the work. In particular, the radiation safety of workers should be ensured in8accordance with the concept of ALARA (to suppress radiation exposure As Low As Reasonably
Achievable).
Note that the basic stance of promptly implementing the decommissioning must be firmly
maintained because if the decommissioning work is delayed excessively, existing high risks willremain over the long term and their risk levels can gradually increase as the buildings andfacilities deteriorate over time. For this reason, regard to the selection of the method of work,
the design and production of equipment and safety systems, and the development of work plans
for the decommissioning work, cautious and comprehensive decision making is required for the
early implementation of the decommissioning in consideration of many constraints such as time,
cost and worker’s exposure needed for associated preparations and work, while giving priority
to limiting the risks involved in the decommissioning work.
Moreover, the decommissioning of the Fukushima Daiichi NPS as a risk reduction project
should be promoted, gaining the broad understanding and support by wide range of public
including local residents. Therefore, it is important to implement an easy-to-understandmechanism of monitoring of risks such as how the overall risks at the NPS have been
continuously reduced through the decommissioning work.

9

3 Technological strategies
Fukushima Daiichi NPS

towarddecommissioning

of

the

1) Fuel debris retrieval
i.

Sectoral target(1) Retrieve fuel debris safely after thorough preparations including safety measures, and bring itto the state of stable storage that is fully managed.
(2) Toward determination of fuel debris retrieval method for the first implementing unit in FY 2019,and start of fuel debris retrieval work for the first implementing unit within 2021, necessary
approaches will be taken, according to policy on fuel debris retrieval.
＜Policy on fuel debris retrieval＞①

Step-by-step approach
We will adopt a step-by-step approach wherein we will set the method of fuel debris retrieval
to be started first in order to reduce risks at an early stage and will adjust our direction flexibly
based on information that comes out as retrieval proceeds.
Fuel debris retrieval, the investigation inside the primary containment vessel, and theinvestigation inside the reactor pressure vessel will be performed in a coordinated, integrated
manner. The fuel debris retrieval starts from a small-scale task and the scale of retrieval will
be stepped up as we review our operations flexibly based on new findings obtained from thenature of the fuel debris and working experience.

②

Optimization of entire decommissioning work
We will examine fuel debris retrieval as a comprehensive plan aimed at total optimization,from preparation to cleanup through retrieval work, discharge, processing and storage,
including coordination with other construction work at the site.

③

Combination of multiple methods
We will combine optimum retrieval methods suitable for the part of each unit where fueldebris is expected to be present, instead of making an assumption that all the fuel debris is
to be taken out using a single method.
At present we will examine how to combine methods from an accessibility standpoint,
assuming that access is made to the bottom of the primary containment vessel from the sideand that access is made to the inside of the reactor pressure vessel from the upper part ofthe vessel.

④

Approach focused on partial submersion method
Given the technical difficulty of stopping leaks at the upper of the primary containment vessel
and expected radiation doses during work, the full submersion method is technically difficultat present, so we will base our efforts on the partial submersion method that is more feasible.
However, given the advantages of the total submersion method, such as being effective inproviding shielding against radiation, we might consider adopting the full submersion methodin the future depending on the progress of R&D.

⑤

Prioritizing fuel debris retrieval by access to the bottom of the primary containment
vessel from the side
According to an analysis, fuel debris is expected to be present in both the bottom of the
primary containment vessel and the inside of the reactor pressure vessel of each unit,
although their distribution varies among the units. In view of rapidly mitigating risks from fueldebris while minimizing any increase in risks that might be caused by retrieval, we will10

prioritize retrieval of fuel debris in the bottom of a primary containment vessel by access fromthe side by taking the following into account:○The bottom of the primary containment vessel is most accessible and a certain amount ofknowledge about it has already been accumulated through the investigation inside theprimary containment vessel;○There is a possibility that fuel debris retrieval could be started earlier;○Fuel debris retrieval could be performed at the same time as spent fuel removalii.

Sectoral strategies
Approach to risk reduction in fuel debris retrieval work
It is hard to consider that the fuel debris immediately appears as a risk, but it is a risk sourcethat risk may grow in case of dealing with haste. Currently, it is maintained in a state with acertain level of stability. However, on a long-term, the possibility of changes in the form andphysical property due to aging degradation is considered. For this reason, as indicated in (1) of
Sectoral goal, fuel debris should be retrieved safely after thorough preparations such as safetymeasures and bring it to the state of stable storage that is fully managed as soon as possible.
To realize this, in the Strategic Plan, securing of safety during the operations of fuel debris
retrieval and technical requirements that are defined including feasibility of fuel debris retrieval
method and stable storage of fuel debris have been considered while organizing the issues
logically. In the future, consideration should be made according to these technical requirements
to implement fuel debris retrieval work safely when expanding the scale with a step by step
approach in accordance with policy on fuel debris retrieval.
How to proceed discussion toward determination of fuel debris retrieval method for the
first implementing unit
In the Roadmap revised in September 2017, policy on fuel debris retrieval has been justdetermined based on the contents of strategic proposals in Strategic Plan 2017. Moreover, it isstated that “regarding the method of fuel debris retrieval for the first implementation unit to begin
the operation, the fuel debris retrieval work for the first implementing unit will start within 2021
by determining the method of containing, transfer and storage (by FY2019) after due
consideration of the results of the preliminary engineering work and R&D”. Fig. 4 shows theinvestigating flow (draft plan) to determine the fuel debris retrieval method for the first
implementing unit, based on the R&D achievements and results of internal investigation of
PCVs. 1: It is necessary to prepare a scenario (operation process plan) during the preliminary
engineering work implemented by TEPCO (see next section), based on the consideration on
the concept of fuel debris retrieval system for each unit and on the evaluation of its applicability
on site. 2: After this, the first implementing unit and the retrieval method will be determined, byconsidering multiple whole scenarios combining the scenarios of each unit and the plan forsurrounding areas and by identifying the whole scenario which is considered to becomprehensively the most reasonable.

11

To select the first implementing unit, consideration should be made for the particularity of
unprecedented undertaking of fuel debris retrieval work in the environment with many
uncertainties, and the benefit of getting experiences and information of handling of fuel debris
early, also taking into account the viewpoints of reliability of internal information, work
environment such as involvement of necessary preparatory works and risk assessment of each
unit, etc.
Internal
Investigation of
PCVs
Incorporate

Needs

Improvement of workplaceenvironment
・ Reduction of radiation dose rate
Incorporate

Study onIncorporate concept of

retrieval

R&D
Needs

⁃Plan forincremental scale
expansion of
retrieval⁃Transferring andstoring method⁃Concept on how tosecure safety, etc.

Needs

Evaluation ofApplicability
at site⁃Safety andreliability⁃Schedule⁃Economical
efficiency
etc.

Establishmentof Fuel debris
retrieval
scenario foreach unit

Study on fuel retrieval
method considering
optimization of site layout
and retrieval scenario of
each unit

Determination of fuel debris
retrieval method to be
applied to the first
implementation unit

Apply the obtained information and study
results appropriately

Site-wide planning• Layout planning• Contaminated water management• Fuel removal from the spent fuel pool, etc.

Fig. 4 Investigating flow toward determination of fuel debris retrieval method (draft plan)

Proceeding method of preliminary engineering and creation of concrete plan of eachtask
In the preliminary engineering work conducted by TEPCO, by confirming the applicability ofoperations on site in light of the situation of each unit about operations and system concept foreach step of fuel debris retrieval proceeded step-by-step, and it will be specified as a scenario
for fuel debris retrieval for each unit. In particular, details of preliminary engineering work should
be fully planned and investigated to obtain the necessary information, aiming at milestones,
which is the determination of fuel debris retrieval method of the first implementing unit within FY
2019.
From this point of view, considerations meeting the following items are expected to be
conducted in the preliminary engineering work: The whole related operations ranging from internal investigation in the preliminary stage offuel debris retrieval and preparations to the improvement in the surrounding environment
to fuel debris storage should be included in the scenario.
 In each step, the information that should be gained in advance should be organized in order
to secure safety and engineering reliability on the equipment for retrieval.
 Clarification of prerequisites as well as evaluation on its uncertainties and forecast
concerning a development of the scenario should be conducted.
 Sufficient safety evaluation should be implemented for the major troubles and others
assumed at present.

12

As a result of these considerations, the following items are expected to be obtained, as theachievement of preliminary engineering work: Image of operation process to fuel debris retrieval for each unit and identification oftechnical issues to solve
 Engineering schedule incorporating the period of solving the technical issues (scenario foreach unit)
As a result, it will be possible to create the overall scenario, combining the obtained scenario
for each unit and fuel debris retrieval from the pools and contaminated water management. And
the candidate of the first implementing unit will be selected according to this overall scenario.
Continued internal investigation and accelerated/prioritized R&D
It is necessary to draw up a roadmap for solving the technical issues extracted so far andidentified in the process of implementing preliminary engineering work, through further internal
investigation and accelerated/prioritized R&D.
As the PCV internal investigation conducted so far has obtained various information, further
detailed internal investigation is planned to collect data such as the distribution of deposits andfuel debris inside the PCV. In the future internal investigation, it should be thoroughly identified
what kind of data is necessary as part of assembling the whole project in preparing for retrieving
fuel debris, which is progressing step by step. Then to implement the scenario for the goal ofeach phase is needed.
In addition, according to the fuel debris retrieval policy based on the partial submersion
method, by advancing the side access to the bottom of the PCV, R&D tasks that newly needs
have become clear are to be proceeded to extract through preliminary engineering work, aswell as accelerating and prioritizing R&D including establishing a containment function (gasphase) on the assumption of the existence of α-nuclides and technology to manage the waterlevel in the PCV. It is also important to take a step-by-step approach to flexibly adjust thedirection including the method of retrieving fuel debris, depending on the outcome of R&D andthe situation on site to which the scenario is applied.
iii. Technical issues for promoting sectoral strategies and future plans
Fuel debris retrieval work should proceed step by step according to the fuel debris retrieval policy.
After presenting the step-by-step concept in (1), the main issues are described in (2) to (5) including
the approach to comprehensively understand internal reactor condition, the technical requirements
related to safety assurance shown in the Strategic Plan, the technical requirements concerning thefuel debris retrieval method, and the technical requirements on the stable storage of fuel debris,
together with further considerations required as the scale grows.
Concept of the step-by-step approach
In the fuel debris retrieval policy, internal investigation and fuel debris retrieval work will be
performed in a coordinated, integrated manner. Starting with small-scale fuel debris retrieval,13the scale of retrieval will be gradually expanded, reviewing the work flexibly, based on the natureof fuel debris and new findings obtained from work experience, etc.
Details of work elements pertaining to fuel debris retrieval for each unit are underconsideration, an example of which is described as follows. Note that these do not necessarily
apply to all of Units 1 to 3 across the board.
a.

Internal investigation
For the condition inside of the PCV and damages of the internal structure, investigation andobservation are to be made provided that the internal environment has not changed. This will
provide information for checking the distribution and accessibility of fuel debris at the bottomof the PCV and information for judging the safety of fuel debris retrieval work, which are used
for examining the fuel debris retrieval method.
Furthermore, the nature of fuel debris inside of the PCV, including the shape, existing state,composition, and mechanical/chemical properties, etc. are identified through sampling andanalysis.
As fuel debris sampling inevitably involves moving fuel debris, it aims to improve theaccuracy of determining the feasibility of the fuel debris retrieval method and to improve thereliability of the protective measures for ensuring safety, by collecting important data thatassists evaluation of ensuring safety in the subsequent stage such as information pertaining
to the transportation for temporarily storage of retrieved fuel debris and stable storage,
information pertaining to the transition state of fuel debris to the gas/liquid phase and potential
criticality, etc.
b.

Fuel debris retrieval
In the initial stage of fuel debris retrieval work, fuel debris will be taken out to the extent thatthe condition of the site is not significantly changed. In order to improve the efficiency of workthroughout the fuel debris retrieval period, various kinds of information to identify the work andequipment used for large-scale retrieval scheduled thereafter should be collected and verified,including to confirm the effectiveness and evaluate the work efficiency of the fuel debris
retrieval work and equipment, to evaluate the effect on safety when extending the scale of fueldebris retrieval and to check in advance the conditions for collecting, transferring and storing.
Based on the data obtained from the operation until the small-scale fuel debris retrieval,installing equipment is to be made that can handle the target amount of fuel debris taken out
per day and more efficient fuel debris retrieval work will be performed after studying the fueldebris retrieval equipment and the system for ensuring safety.
Comprehensive

understandingofreactorconditions

bycontinuinginternal

investigation, etc.
The comprehensive analysis and the evaluation results are as shown in Fig.5, that including
actual measured value of plant parameters, etc. severe accident progress analysis, information

14

by PCV internal investigation, which are obtained at the time of accident as well as the accessroute to fuel debris and the situation of the surrounding structure and the distribution of fueldebris of the Unit 1 to 3 based on the knowledge obtained by examination, etc.
Unit 2

Unit 1

Unit 3Spent fuelSpent fuelSpent fuel

Core

Core
Water Levelin PCVapprox. 2m

Reflection from survey
in future because of
non-observation

Water Level in
PCV approx.
30 cm

Fuel Debris

RPV Lower
Head

Water Leakage(visual observation)

A small amount of fuel debris is present
A small amount of fuel debris is present
in the inside and on the outer surface of
the CRD housing
Large amount of fuel debris is present
A small amount of fuel debris is present in the inside and on the outer surface of
the CRD housing

Most of the fuel debris is present

A small amount of fuel debris is present

Fuel debris may have spread on thepedestal outside through the personalentrance

The possibility of fuel debris spreadingon the pedestal outside through thepersonal entrance is low.

Unit 1X-6 Penetration

CRD rail

Pedestal

Information of
the structurearound fueldebris

•

•
•





X-6 Penetration

There is no large damage on the surfaceof the pedestal outer wall above thesteel grating.

Fuel debris remains on the RPV lower
head party
A small amount of fuel debris is present
in the inside and on the outer surface of
the CRD housing.
Amount of fuel debris in Unit 3 is morethan that in Unit 2.
Fuel debris may have spread on thepedestal outside through the personalentrance.

X-6 Penetration

Steel grating

It is possible to access to the D/Wbottom from the upper side.
State around the CRD rail connecting to
the pedestal from the X-6 penetration is
not observed.

Little fuel debris remains

CRD Housing
Pedestal

X-53 Penetration

Pedestal Inside
DepositCRD rail

Pedestal Inside

CRD Housing

CRD rail

CRD Guide tube

Pedestal
InsideSteel grating
Steel Grating
Upper tie plate

Water Leakage(visual observation)

Unit 3

CRD Housing

Unconfirmed, to reflect
results of planned survey





Unit
Unit22
Pedestal

Steel grating

Information of
the accessroute for fueldebris*Fuel Debris

Little fuel debris remains(Stub-shaped fuels might exist in
peripheral region)High dose rate

Fuel Debris

Personal
EntranceLittle fuel debris remains

Pedestal
OutsideWater Leakage(visual observation)

Pedestal Inside 

Water Levelin PCVapprox. 6 m

Personal
Entrance

Personal
Entrance

Core Region

Core









Supporting pillar
Cable tray

There is no large obstacle on the CRD
rail and around an entrance to thepedestal inside.
It is possible to access to the pedestal
inside through an entrance.
However a part of fuel assembles fall,no large damage is observed on CRD
housing support.
No large damage is observed on innerwall and structures of the pedestal.







It is possible to access to the pedestal
inside through an entrance.
Some damaged structures and the fallof the CRD housing support wereobserved in the pedestal inside.
No large damage is observed on innerwall of the pedestal.

It is thought that a route to the pedestal inside from the X-6 penetration is important for fuel debris retrieval from asmall-scale task by side access method. The contents observed by previous internal investigation are mentioned as
information to judge whether troubles are caused by falling objects on the route.
In the access route for the fuel debris retrieval in the PCV (large-scale task), an access route through an equipment
hatch is planning in the project of retrieval method and system.
Due to high dose rate around the X-6 penetration of Unit 1, it may use the same access route of the large-scale task, incase it is difficult to improve work environment. Next internal investigation of Unit 1 is scheduled to develop by
accessing from X-2 penetration.

(Prepared by Achievement Report 2017 and June 2018 of “Decommissioning and Contaminated Water Management Fund (Advancement ofcomprehensive grasping of inner reactor)” provided by IRID, The Institute of Applied Energy)

Fig. 5 Estimated fuel debris distribution, access route and surrounding structure of Unit 1 – 3The following investigation and study for each unit should be considered steadily.
【Unit 1】
 Grasping distribution of structures or deposits outside the pedestal (including sampling)〔scheduled in the first half of FY2019〕【Unit 2】15

 Grasping mobility of deposits at the bottom of the pedestal when force is applied〔scheduled in the second half of FY2018〕
 Grasping distribution of structures or deposits inside the pedestal (including sampling)〔scheduled in the second half of FY2019〕
 Considering to increase sampling volume〔scheduled in FY2020〕【Unit 3】
 Considering availability of internal investigation technology that was developed andproved by the project of decommissioning and contaminated water management project,in parallel to study water level reducing in PCV
 Considering necessity of further investigation in utilizing underwater ROV that was usedin the former investigation
FY2018

1st

2nd

1st

Approx.
1m 1m

Pan-tilt
camera2nd

Grasping distribution of
structures or deposits inside thepedestal (including sampling)

Thruster Approx.
0.3m
0.3m

Lighting

Investigation Unit
(Ultrasonic range finder, etc.)

Investigationequipment by boat-type access with
潜水機能付ボート型アクセス・調査装置
submerging
function (Current image)（現時点のイメージ図）

Investigationequipment by arm-type access
アーム型アクセス・調査装置(Current image)（現時点のイメージ図）

Unit 2

Grasping mobility of deposits at the bottomof the pedestal when force is applied
PCV
Φ110mm(X-6

FY2021)

Consider to increasesampling volume

Image of internal PCV investigation using guidepipe

Unit 3

Considering availability of internal investigation technology that has been demonstrated in parallel tostudy water level reducing in PCVConsidering necessity of further investigations in utilizing ROV that was used in the previous investigation

Start of fuel debris retrieval for the first implementation unit

Grasping distribution of structures ordeposits outside the pedestal (including
sampling)

FY2020

Determine the method of fuel debris retrieval
for the first implementation unit

Unit 1FY2019Drawings in the balloons are quoted by the material from IRID, TEPCO

Fig. 6 Further internal investigation schedule and image of investigation equipment
Prior to implementing further internal investigation in detail, giving due consideration will be
required for continuous ensuring safety, including maintaining containment function and prompt
recovery of containment function in the abnormal event as well as measures against exposureand dust management, in consideration of maximum use of existing penetration into internal
PCV that has been used in the former investigations as larger equipment will be used.
Technical issues and future actions for ensuring the safety of fuel debris retrieval work
For ensuring the safety at the each stage of the fuel debris retrieval, it is important to study
reasonable protective measures according to the scale of fuel debris retrieval work while taking

16

actions to reduce the uncertainties of the PCVs’ internal conditions during the conceptual designphases. In the Strategic Plan, as the concept of ensuring the safety during the fuel debris
retrieval work is being constructed, the key technical issues for ensuring the safety of fuel debris
retrieval are carefully selected and studied as follows.
①

Establishing the containment function (Gas phase)
When retrieving the fuel debris, the dispersion of radioactive fine particles ( α -dust)
containing α-nuclides may occur due to the works such as fuel debris cutting and drilling, andit may create a concern for increasing the concentration of radioactivity in the PCVs gas phase.
Therefore, a function for containing the gas phase with protective measures should be
provided that suppress the dose impact of workers and public within the allowable value, by
minimizing the spread of αdust from PCV.
Accordingly, it is reasonable to upgrade the scale of the retrieval work while verifying thevalidity of the containment function built in the subsequent stage by grasping the tendency of
dust dispersion at the each stage of scale expansion. For example, internal PCV investigations
and the small-scale retrieval planned in the near future, α-dust emission can be controlled by
reducing the amount to be retrieved, and selecting a retrieval method that does not involve
cutting and drilling, while maintaining the current inert atmosphere (slightly positive pressurestate due to nitrogen gas charge) inside the PCVs. Based on both the results of monitoringchanges in the state of α-dust emission from the retrieval work and the evaluation of theeffects on the surroundings, it will likely be shifted to the larger size of the fuel debris retrieval
work gradually, using such as the cutting and drilling equipment. If it is evaluated that the
expansion of the retrieval work may induce effects on the surrounding environment, further
study is required for the means to strengthen the containment function by equalization or
negative pressurization inside the PCVs as well as constructing a secondary containment
function outside the PCVs.

②

Establishing the containment function (Liquid phase)
To mitigate the dispersion rate of generated α-dust and to minimize the transition to thegas phase, the fuel debris retrieval work would be performed, submerging the fuel debris or bypouring water over the fuel debris. In such cases, a great number of α-particles will be mixed
in cooling water (liquid phase). To prevent the cooling water containing α-particles from
affecting the environment, it may be of great importance to establish a cooling water
circulation/purification system, and a liquid phase containment function.
To ensure a more reliable containment function, water sealing methods by repairing thebottom of the PCV pouring the grout materials have been studied. However, based on the
results of previous experimental studies, it is becoming clearer that water sealing by repairing
the bottom of the PCV is very difficult. Thus, it may be important to explore a retrieval method,
to minimize leakage with the realization of suitable circulation and purification systems ofcooling water.

17

To establish a reasonable containment function at each stage as scale grows, it is rational
to monitor the radioactive concentration of the cooling water and verify the validity of thecontainment function built in the subsequent stage. For example, if the PCVs internal
investigations and small-scale retrieval work are performed using the current water circulation
system, it may be possible to suppress the increase of the radioactive concentration of coolingwater by reducing the retrieved volume and selecting a retrieval method that does not require
drilling, together with the containment function (gas phase). From the viewpoint of investigating
the methods to detect the effects induced by the retrieval work on the liquid phase, thecirculating water system would be monitored, and based on the confirmation of monitoring
results ofα-nuclides, the fuel debris retrieval method may gradually be changed to a larger
retrieval method using drilling equipment. If an abnormal event such as a large volume ofcooling water outflow from a PCV to the torus rooms of a nuclear reactor building occurs,
measures should be taken such that the water level in the torus room be maintained lower
than the groundwater level to prevent the outflow of cooling water to the surrounding ground.
For this reason, it is necessary to establish an appropriate PCV water level and a PCV waterlevel control system.
③

Maintaining the cooling function
The decay heat of the fuel debris has been decreased dramatically since the core melt
accidents. However, it may be necessary to keep the cooling function to prevent nuclides fromshifting from the liquid phase to the gas phase due to thermal energy during the fuel debris
retrieval work. At present, the cold shutdown state is maintained with keeping the temperature
well below 100℃ using cooling water. In addition, during the fuel debris retrieval work, it may
be necessary to keep the temperature below the level at which the fuel debris retrieval device
can continue to work without any problems for a long period of time.
To maintain the cooling function at each stage of retrieval scale expansion, the consistency
with other systems should be checked, such as the concept of water level control within the
PCVs for confining the liquid phase and the contaminated water purification system. Based on
the data obtained for each stage of retrieval scale expansion, it may be necessary to examine
the circulation cooling system to be required in the subsequent stage.

④

Criticality control
At present, the monitoring of the concentration of rare gas (Xe-135) has shown no sign ofcriticality. Further, it may be pointed out that the possibility of criticality is extremely low basedon the expected state of existence of fuel debris. In addition, even if criticality should occur, its
impact would be small because it is estimated that the fuel debris is dispersed over wide area.
To keep the subcritical condition more reliably, it is important to store the retrieved fuel debris
stably, controlling the shape and size of retrieved fuel debris, for instance, by storing the debris
in storage cans. To prevent fuel debris from reaching criticality during the fuel debris retrieval
work, it is necessary to investigate what kind of conditions during the work would lead to18

criticality, including the shape of the fuel debris or the water volume changes, and establish an
appropriate management method with combined functions of prevention, detection, andtermination of criticality.
In the early stage of retrieval, the fuel debris should be retrieved in a way that does not
significantly change the shape of fuel debris. Then, the composition and characteristics of fueldebris and the fluctuation of the neutron signal in the vicinity of fuel debris handled during thework should be checked to evaluate the criticality of the fuel debris. The retrieved volume offuel debris can be increased based on the measurement of subcritical condition or taking
measures such as placing neutron absorbers.
⑤

Securing structural integrity (earthquake resistance) of the PCVs and reactor buildings
The reactor buildings, PCVs, and reactor pressure vessels (herein after referred to as“RPV”s) experienced the hydrogen explosions when the accident occurred. Further, theexposure to the high-temperature environment and the corrosion due to seawater injection
may have affected the integrity of the structures. During the period of the fuel debris retrieval
work, it is necessary to secure the integrity for the important structures like PCVs and RPVs
and to suppress the deterioration of containment functions of PCVs and reactor buildings,
considering the effect mentioned above against the possible occurrence of a severe
earthquake. In addition, the deterioration of containment function of PCVs and reactor
buildings due to corrosion have to be suppressed during the retrieval work. Furthermore, it
may be required to prepare for the mitigation measures in advance, evaluating the impact onhuman beings and the environment induced by the postulated damage to important functions
due to a large earthquake.
The previous studies show that the reactor buildings and structural major components of
PCV, RPV and pedestal, that supports the RPV of each unit, have relatively large seismic
safety margin against a design basis seismic ground motion Ss (600Gal), taking into accountthe damage caused by the accident, degradation over 40 years by corrosion and increased
weight of new facilities required for the fuel debris retrieval work.
It is necessary to evaluate the seismic safety margin of R/Bs, PCVs and RPVs in moredetail and to implement the countermeasures, according to the progress of the further PCV
internal investigation and the studies of the fuel debris retrieval methods.

⑥

Reducing radiation exposure for occupational workers
The main work areas of the fuel debris retrieval are high dose areas such as inside thereactor buildings. Also, in the new stage of fuel debris retrieval, there comes a need handlingof nuclear fuel materials containing α-nuclides with a large internal dose impact. Accordingly,
continued strict control of not only for external exposure but also for internal exposure isessential.
Specifically, it is important to prevent excessive exposure to occupational workers throughappropriate radiation protection schemes depending on the working environment and working

19style. Regarding protection from external radiation exposure, the radiation exposure dose isevaluated considering the radiation sources and the dose rate in the work area. Then, basedon the three principles, namely “time, distance, and shielding", it is needed to take measures
to keep the radiation exposure dose as low as reasonably achievable. Regarding theprotection from internal exposure, measures such as suppressing dispersion of radioactive
dust and prevention of contamination expansion are being taken and appropriate protective
measures are to be selected depending on the target nuclides, concentration in air and surface
contamination density in the work area, to prevent inhalation ingestion and body pollution.
Technical issues and future actions for fuel debris retrieval method①

Securing access route
For transporting, installing and unloading the equipment and devices used for fuel debris
retrieval, and transporting fuel debris and waste, an access route should be established byremoving obstacles and reducing the dose to the level at which such tasks can be done. Whenestablishing a new opening in the PCV or the like to construct an access route to fuel debris,it should be kept in mind to suppressing the release of radioactive materials from the PCV and
RPV and maintaining the integrity of existing structures.
According to the fuel debris retrieval policy based on the partial submersion method that
extends the side access to the bottom of the PCV, TEPCO is now conducting the preliminary
engineering work. Based on the results of R&D of decommissioning and contaminated water
management, an access route from the PCV side opening to the fuel debris is to beconstructed. Then, it will be drawn up a plan in which a side wall opening is made on thereactor building and the side wall opening on the PCV is enlarged as required.
According to the fuel debris retrieval policy, the optimum retrieval method should be selected
depending on where the fuel debris exists for each reactor unit. At present, it is considered on
the premise of accessing from the top to the inside of the RPV.

②

Development of devices and equipment
Devices and equipment for accessing fuel debris and retrieving them safely, reliably, andefficiently should be developed. To flexibly respond to the situation on the site, these equipment
and devices must meet the specifications of radiation resistance, remote inspection/
maintainability, high reliability, and relief mechanisms that do not disturb the subsequent work
if a trouble occurs.
Accordingly, the development of a recovery system that can handle various conditions offuel debris, a fuel debris cutting system, and a dust collecting system, is underway.
Furthermore, a technique for installing retrieval equipment is required. The technology used
for remote operation, including installing the working cell for establishing a containment
function (gas phase) and the device for removing obstacles to provide an access route, arenow under development. The developed equipment and devices will be combined and undergo

20mock-up tests to verify that the performance mentioned above is demonstrated on the actualsite.
③

Establishment of system equipment and working areas
When retrieving fuel debris, it is necessary to install system equipment to establish safetyfunctions and operate them appropriately. Also, it should be prepared that sufficient spaces for
installation, operation, and maintenance, and for installing shields for reducing radioactive
exposure to operators, so that the required environmental conditions are satisfied.
The system equipment include a negative pressure control system required for establishinga containment function (the air phase), a circulating water cooling/purification system required
for maintaining the containment function (the liquid phase) and cooling function, and a criticality
control system required for controlling criticality. Because it is essential to monitor the internalsituation when retrieving fuel debris, the development of measurement systems (pressure,temperature, radiation, etc.) is an important future issue to be addressed. An investigation on
how to implement the system equipment integrating these systems is under way.
The working area required for installing the fuel debris retrieval equipment/related devices
and system equipment is now being calculated. Considering the handling of the high-dosearea in the reactor buildings and interference with other tasks, study of setting up the systems,
including outside of the existing buildings, is underway.
Technical issues and future actions for safe and stable storage of fuel debris①

Handling of fuel debris (collecting, transferring, storing)
The fuel debris retrieval work requires to establish a comprehensive system consisting of aseries of steps from collecting, transferring to storing of retrieved fuel debris furnished withsafetyfunctions

such

as

maintaining

subcriticalcondition,

containment

function,countermeasures against hydrogen generation, and cooling. Specifically, the basic
specifications of the canister such as the total length and inner diameter has been studied
taking the handling property, the storing rate and maintaining of the subcritical condition into
account. The allowable transportation period has been investigated in accordance with theestimated volume of hydrogen generation from canister. Based on these results, details ofequipment/systems for collecting, transferring, and storing of the retrieved fuel debris need tobe discussed. Storing facility adaptable to the safeguards requirement is also required to bestudied based on the estimated volume of retrieved fuel debris. It is also important to plan
mock-up tests for confirmation of handling of the canister combined with a fuel debris retrieval
device.
Proper handling method/devices for retrieved fuel debris in the subsequent stage need to bestudied and improved taking the information/data obtained from work experience in previous
stage as well as above mentioned technical issues into account.

21

The Roadmap states that the processing and disposal method of the retrieved fuel debris areinvestigated and fixed during the third phase after starting the fuel debris retrieval work.
②

Treatment of radioactive waste during fuel debris retrieval work
During fuel debris retrieval work, various radioactive waste such as replaced ordisassembled components or parts other than retrieved fuel debris are to be generated fromfuel retrieval facility inside/outside of the PCV at each stage of its preparation, retrieval andcleaning work. It should be properly classified and stored under safe condition same as fueldebris.
It is important to develop a classification standard in order to judge appropriately suchmaterial into fuel debris or radioactive waste during retrieval work, even if only limited
information on the retrieved material is available in advance. From above reason, detailed
studies on treatment of retrieved materials including classification standard needs to becontinued based on the findings and information obtained from the investigation inside of the
PCV.

③

Safeguard policy for fuel debris
For the units 1 to 3 of the Fukushima Daiichi Nuclear Power Station, implementation of
conventional material accountancy and safeguards is deemed difficult since the fuelassemblies as the basis of the material accountancy would no longer maintain their original
shape due to melting, the broken facilities would not allow necessary containment/surveillance
schemes, and high radiation would restrict the entry of human beings into the areas andprevent normal inspection activities, and so forth. Additional safeguards operations are
currently applied under this situation to the units 1 to 3 as an alternative measure to ensure no
undeclared relocation of nuclear materials, etc.
Given, however, the fuel debris retrieval work cause the movement of nuclear materials,
corresponding safeguards operations will be required. Japan is providing updated informationof the units 1 to 3 of the Fukushima Daiichi Nuclear Power Station to the stakeholders including
the International Atomic Energy Agency (IAEA), aiming at the prompt and smooth applicationof the safeguards in the FDR operations. In addition to these activities, the realistic andtransparent enough material accountancy and safeguards must be proposed to reach theglobal agreement among the stakeholders including IAEA.
Technical issues and further plans described in this article is as shown in Fig. 7.

22

23

Access Route &Equipment for Survey

Technologies of Fuel Debris

2019

2020

Determination of fuel debris retrieval methods
for the first implementing unit

2021
Start of fuel debris retrieval
at the first implementing unit

2022

Continued as necessary→

Continue as necessary

Measurement for ensuring safety during large-scale fuelretrieval and study on safer handling of fuel debris

Retrieval method (layout plan)
Collecting/transferring plan
Storage plan
Ensuring of Safety(confinement, water level control,

Small-scale retrieval &Preparation of large-scale retrieval

Retrieval equipment
Facilities for collecting, transferringand temporary storage
Radiation protection for safety(modification of existing facility)

Preliminary engineering / Detailed engineering

Retrieval method (Layout plan etc.)
Collecting/transfer plan
Temporary storage plan
Securing Safety

Research and development

Technical studies for on-site work

On-site work

Transfer method to outside the site
Adaption plan for Safeguards
Additional plan for internal investigation

Preparation of small-scale retrieval

Continue as necessary

Analysis technology
for fuel debris

Access Route &Equipment for Survey

Preparation of investigation/ internal investigation/ Characterization of fuel debris (from retrieved samples etc.)

Retrieval method,
system & concept design

2018

Fig. 7 Technical issues and further plan on fuel debris retrieval

inside PCV- Development of collection, transport, and Storage- Development of closed circulation systems for water

Retrieval and Internal Structure of Fuel Debris

Fuel Debris- Advancement of Fundamental Technologies forStudy for subsidized project on dicommissioning andcontaminated water management- Advancement of Retrieval Method and System ofEngineering involved with fuel debris retrieval

Retrieval of fuel debris

Engineerng for internal investigation- Development of Investigation Technology of Inside RPV- Development of Technologies for Grasping andAnalyzing Properties of Fuel Debris

to Retrieving Fuel Debris and Internal Structure- Development of Sampling Technologies- Develoment of Technologies for In-depth Investigationof PCV Inside

Study for subsidized project on dicommissioning andcontaminated water management

Internal Investigation

Milestone

Fiscal Year

2) Waste managementi.

Sectoral target(1) As the approaches of solid waste storage, the Solid Waste Storage Management Plan
(hereinafter referred to as the “Storage Management Plan”) is appropriately developed, revised
and implemented including waste prevention, volume reduction and monitoring, with updating
the estimated amount of solid waste to be generated in the next ten years periodically.
(2) As the approaches for processing/disposal, countermeasures integrated from characterization
to processing/disposal of solid waste will be proceeded from the expert point of view, and theprospects of a processing/disposal method and technology related to its safety should bemade clear by around FY2021.
＜Basic policies on solid waste＞① Thorough containment and isolation
Solid waste management should be implemented thoroughly, with containment and isolation ofradioactive materials to prevent their dispersion/leakage and human access to them, in order not cause
harmful radiation exposure.
② Reduction of solid waste volume
The amount of solid waste generated by decommissioning is reduced as much as possible in orderto ease the burden of solid waste management.
③ Promotion of characterization
To proceed with study on processing and disposal method of solid waste, characterization of solid
waste such as nuclide composition and radioactive concentration is needed. In addition to the fact thatsolid waste of the Fukushima Daiichi NPS is large in volume, and have varied nuclide compositions, itis necessary to address an increase in the number of analysis samples and proceed theircharacterization properly.
④ Thorough storage
To dispose of solid waste, it is essential to understand the volumes and characteristics of the solid
waste, and to establish specifications of disposal facilities and technical requirements for waste
packages (technical requirements for disposal). However, the volumes and characteristics of solid
waste will become clear step by step, with the future clarification of progress and plan ofdecommissioning. Therefore, the solid waste generated should be stored safely and reasonably
according to characteristics of solid waste. Storage capacity should be secured to ensure that the waste
can be stored within the site of the Fukushima Daiichi NPS.
⑤

Establishment of selection system of preceding processing methods in consideration of disposal
In order to safely store solid waste, the system for selecting the method of processing for stabilizationand immobilization (preceding processing) will be established, and selecting the method of thepreceding processing, before the technical requirements of disposal are established.

⑥ Promotion of effective R&D with a bird’s-eye-view of overall solid waste management
To efficiently proceed with R&D concerning solid waste management, close cooperation should be
realized between R&D fields such as waste characterization, processing and disposal. Issues anddiscussions on R&D should be shared between parties, and necessary planning made with a bird’seye-view of overall solid waste management, should be progressed collectively.
⑦

Efficient implementation of R&D projects from the perspective of overall solid waste management
In order to continue safe and steady solid waste management, the continuous operational frameworksystem including development of adequate facilities and human resources, which are concerned withsolid waste management, must be undertaken.

⑧ Measures to reduce radiation exposure of workers
To steadily proceed with solid waste management, it is important to ensure the safety and health ofworkers. Therefore, radiation exposure control, safety management and healthcare programs shouldbe implemented thoroughly based on the relevant laws/regulations.
(Note) Numbered and titled by NDF for each item.

24

ii.

Sectoral strategy
The concept of risk reduction in waste management and basic policies on solid waste
The solid waste stored on the sites, such as “rubble, etc.”, is unlikely to increase in risk in the
future, but they are still a source of risk which should make its countermeasures properly in thedecommissioning process. They are in a state where the risk level is generally lower than othermajor risk sources, and it is considered that a constant risk level can be continuously maintainedby appropriate maintenance and management in the future.
The challenge on solid waste generated by decommissioning of the Fukushima Daiichi NPS
is the existence of a large volume of waste with various characteristics. For this reason, in
addition to improving the capability of analysis for characterization, it is necessary to develop a
flexible and rational waste stream. Specifically, the relevant organizations should proceed theirefforts based on each role in line with the basic policies of solid waste management that wascompiled in the Roadmap, and the technical study on the integrated countermeasures from thecharacterization to processing/ disposal of solid waste will be proceeded with following policies
at the initiative of NDF.
Storage
The fundamentals of managing solid waste are to contain not to scatter or leak. Also, it should
be kept isolated in a properly storage place, and managed appropriately by monitoring and soon. It is important to instill the concept of the waste hierarchy, and raise awareness on reducing
the volume of solid waste to be generated.
To store solid waste properly, TEPCO releases its Storage Management Plan, and estimates
the volume of solid waste that will be generated in the next ten years, and shows their policy
such as on building waste management facilities to be required based on the volume. Since theestimated amount of generation fluctuates depending on the progress of the decommissioning
work in the future, it is necessary to revise the volume estimation once a year and update theStorage Management Plan as appropriate.
Further safety improvement in storage
The secondary waste generated by water treatment, which has high fluidity, should be stored
in a more stable and reasonable way. In general, it is ideal to conduct waste processing basedon the technical requirements of disposal once it is established, if the processing is conductedprior to disposal. However, there may be cases where processing for stabilization andimmobilization are required although the technical requirements for disposal are not determined(i.e. preceding processing). Therefore, study will be continued on how to select the preceding
processing method with disposal in mind.
Study on the processing/disposal policy
The Roadmap specifies that the prospects of a processing/disposal method and technology
related to its safety should be made clear by around FY2021. The overall picture of solid waste

25becomes clear step by step according to the progress of the effort. Keeping in mind that it will
still remain in a stage of accumulating necessary information on its characteristics around
FY2021, the concrete targets for technical perspective are listed as follows: Establish safe and rational disposal concept based on characteristics and volume of thesolid waste generated in the Fukushima Daiichi NPS with its applicable processing
technology, and develop safety assessment method reflecting features of the disposal
concept, with considering examples of foreign countries
 Clarify radiological analysis and evaluation method for characterization
 Clarify processing technology that would be expected to introduce actual equipment forstabilization and immobilization considering disposal for several important waste streams
such as secondary waste generated by water treatment
 Establish method of rationally selecting processing technology to stabilize and immobilize
waste based on the above methodology although the technical requirements for disposal
are not determined (i.e. preceding processing) Have prospect of setting processing/disposal measure for solid waste of which theprocessing technology considering disposal is not clarified, using a series of method to be
developed by 2021
 Clarify issues and measures concerning storage of solid waste before conditioning
It is described in the Roadmap that in accord with these efforts, specifications and production
methods of the waste packages should be determined in the third phase. Then, a processing
system should be installed in the Fukushima Daiichi NPS. After establishing the prospects ofdisposal, production of waste packages should be started, and then carried out
iii. Technical issues and plans for promoting sectoral strategies
Promotion of characterization
Under the circumstance that the Building 1 of JAEA Okuma Analysis and Research Centeris scheduled to commence operation at the end of FY2020; it is important to improve theaccuracy of models to obtain evaluation data based on the limited number of radiologicalanalysis data. The study will be proceeded on the method of reflecting dispersion of radiologicalanalysis data to inventory evaluation using analytical method, and concept of setting andrevising radioactive inventory based on comprehensive evaluation of radiological analysis data
and analytical value.
The radiological analysis has been conducted for characterization so far, but target ofradiological analysis will be mainly on the predisposal management and review targeted
nuclides in near future. The study on radiological analysis to make it simple and rapid isproceeded together to develop efficient radiological analysis method. Through these efforts, asystem, facilities and equipment, and technologies for highly accurate characterization of solid
waste will be established by the end of FY 2020, and necessary radiological analysis data will
be acquired for some solid waste.

26

Further safety improvement in storage
The secondary waste generated by water treatment is proceeded to be dehydrated forstabilization, and extracted and transferred from temporary storage facilities to storage facilities
on a hill as risk reduction measures for the time being.
On the technologies for stabilization, immobilization and conditioning of the secondary waste
generated by water treatment, challenges for introducing actual equipment should be dealt, andgathering and evaluation of data on technical requirements should be proceeded. Processing
technology expected to be applicable for actual processing should be identified, andspecification of waste package should be determined, from the point of view whether it may
contributes to establish selection method for preceding processing method.
Regarding the methods of storing high-dose solid waste generated during fuel debris retrieval,study should be proceeded on the items such as the way of sorting fuel debris/waste, the typeof waste, the evaluation of waste volume, and the flow of handling waste, and narrow down
candidate methods for storage.
For other solid waste, study should be proceeded on generation of hydrogen during storage,
together with the timing and content for the case of requiring further measures to secure safety,
and reflects to the Storage Management Plan as needed.
Establishing processing/disposal concept and development of safety evaluation
methodIn order to select candidate technology as a preceding processing method, it is necessary to
conduct safety assessment with the specification of the waste packages that is developed byrespective candidate technologies, as a target. For that reason, selecting reasonable andfeasible candidate technologies and developing safety assessment methods will be proceededby the end of FY 2021.
OthersAs solid waste to be generated with the retrieval of fuel debris in future, structures such ascore internals and outside of reactors to be dismantled and removed, and second waste suchas filters generated during fuel debris retrieval related works are expected. It is necessary toproceed study on the storage method for the solid waste together with the study on the methodof fuel retrieval.
Technical issues and further plans described in this article is as shown in Fig. 8.

27

Fiscal Year

2015

2016

2017

１．Reduction of solid waste

2018

2019

2020

2021

2022 and later

Carry-in control, reuse, recycling and volume reduction

２．Waste characterization
Sampling(1) Analysis data acquisition,
management, etc.

Analysis and measurement forverification of waste for disposal
Development/establishment of methods
on verification of waste for disposal
Planning/updating analysis plan, conducting analysis, characterization, accumulation/evaluation/management of analysis data

Development of sampling technique etc. (Method of sampling high-dose samples)
Development of sampling technique etc. (Method of sampling high-dose samples)

Establishment of Database system

Development of radioactive material analysis and research facilities(2) Improvement of analysis
Human resource development for analysis personnel

capacity(3) Improvement in efficiency ofDevelopment of characterization method with complimentarily use ofdata evaluated from nuclide migration model

waste characterization
Optimization of the number of analytical samples, review of nuclides
to be analyzed, simplified and speed-up analysis methods, etc.

３． Storage

Storage(1) Storage Management Plan

Development and review of the Storage Management Plan

(2) Studyand evaluation of

Study on Storage measures of secondary waste from water treatment

Study on safety
improvement
measures

Storage method
Study on storage method, storage containers,
and the way of putting waste into container(3) Study and evaluation of storage
methods of solid waste generated

Design/prepare
Storage containers

during fuel debris retrieval

４． Development of

Establishment of a selection system of preceding procesing

process/disposal concept
Survey and setting of disposal method
based on characteristics of solid waste

and development of safetyassessment method

Survey and development of safetyassessment method for each disposal method
Survey on conditioning
technology

Technical development of processinhg methods related to stabilization and immobilization

Compilation of basic concept ofprocessing/disposal

Clarification of prospects on processing/disposal
method and safety technology

Study of processing/disposal

Fig. 8 Technical issues and further plan on waste management28

Use of a
selectedsystem3) Contaminated water managementi.

Sectoral target(1) Under the three basic principles concerning contaminated water issues (“Removing”
contamination sources, “Redirecting” fresh water from contamination sources, and “Retaining”
contaminated water from leakage), the reinforcement and optimum operation of the water level
control system should be continued. The multilayered measures should be implemented tocomplete the processing the stagnant water in the buildings by 20201.
(2) Considering the total decommissioning process including the full-scale fuel debris retrieval
beginning in near future, the long term strategy should be examined for the measures of thecontaminated water.
ii.

Sectoral strategy
Concept of risk reduction in contaminated water management
For the contaminated water management, various measures based on the three principles
has been implemented both to the contaminated water in the buildings and trench/pits anduncontaminated water such as groundwater/storm sewage. The stagnant water in the buildings
is the liquid containing a considerable amount of dissolved radioactive materials and its hazard
potential is relatively high. Thus the stagnant water is required to be dealt with as soon as
possible.
The stagnant water has been treated with cesium adsorption apparatus and the radioactive
materials are transferred to the secondary waste such as adsorption vessel, so that the stagnant
water is reducing its risk level.
Steady execution of contaminated water management stated in the Roadmap
From a situation requiring urgent countermeasures immediately after the accident, it isthought that it has shifted to a certain stable state where it is possible to forecast a medium tolong-term plan to some extent by preventive and multilayered countermeasures based on thethree principles on the issue of contaminated water. The milestones mentioned in the Roadmap
are as follows: (1) reduction of the contaminated water generation to about 150 m3/day (by 2020),(2) storing all the water treated by nuclides removal equipment in the welded type tanks (FY2018) (3) by lowering the level of stagnant water in the buildings, separation of the penetrations
between Units 1 and 2 and between Units 3 and 4, respectively (by 20182), (4) reduction of theradioactive materials in the stagnant water in the buildings up to approximately one tenth of theamount at the end of FY 2014 (FY 2018), and (5) completion of the treatment of stagnant waterin the buildings (by 2020), and the tentative actual measures for achieving these milestones

Exposing the floor line for buildings other than the reactor building and lowering the water level of the reactor
building to T.P.-1740mm (O.P. - 300 mm or less) (Circulating water injection cooling is carried out in the reactor
building, and stagnant water continues to exist).
1

2

Completed in September 2018.

29

have already been identified. It is expected to achieve the milestones by implementing thesecountermeasures steadily.
Study on contaminated water management based on the relation with fuel debris
retrieval work
Because full-scale decommissioning work including fuel debris retrieval will start after a while,
it is necessary to discuss the optimal control of contaminated water and groundwater together
at each stage of the decommissioning process.
According to the target process of the Roadmap, it is considered that the processing of
stagnant water in the buildings other than the reactor buildings of unit 1 - 3 will be completed by
2020. By that time, a circulation system in which the stagnant water is recovered in the reactor
buildings (instead of turbine buildings) and purified to be used as a coolant should beestablished. Furthermore, the study including feasibility of the PCV circulation cooling system
for fuel debris retrieval work is under way, and to secure multiple boundaries, water shielding
by repairing the bottom of PCVs has been examined. However, it has been found that complete
water shielding through repairing the bottom of PCVs is very difficult, so the circulation systemshould prepare for the inflow of α-particles from inside of the PCVs to the stagnant water in thereactor building. Even if the water shielding is applicable, it is necessary to consider setting asufficient difference in water level between stagnant water in the reactor building andgroundwater, in case a large amount of cooling water leaks from a PCV into the reactor building.
As the fuel debris retrieval proceeds and water injection for cooling the fuel debris is nolonger necessary, the injected cooling water will not stay on the lowest floor of the reactor
building. In that case, the groundwater level should be adjusted to a level below the lowest floorof the reactor building, so it can be expected that there is no water inflow into the reactor building.
In such a case, it is important to build a system that can stably control the groundwater level fora long period, such as by combining passive equipment with fewer machine troubles than otherdynamic equipment.
iii. Technical issues and plans for promoting sectoral strategies
Steady execution of contaminated water management stated in the Roadmap
Stable management of groundwater around the buildings has been made by strengthening
the sub-drain function and installing land-side impermeable wall, etc.
Study on contaminated water management based on the relation with fuel debris
retrieval work
When retrieving the fuel debris, fuel debris-derived substances including α-particles may betransferred to the PCV circulation cooling system. Therefore, the PCV circulation cooling system
must properly remove them. To handle the constant generation of water inflow into the buildings,
it is necessary to set the conditions for receiving a part of water treated by the PCV circulation
cooling system in the existing stagnant water circulation system.

30

Technical issues and further plans described in this article is as shown in Fig. 9.
Fiscal Year

2018

2019

2020

2021

2022

On-site work
Technical studies for on-site construction"REMOVING " contamination sources

Additional effective doses at thesite boundary .

Treatment with purification Systems
Reducing the total amount of contraminated water to about 150m3 per day"REDIRECTING " fresh waterfrom contamination sources
Reducing the total amount ofcontraminated water to about
150m3 per day by rainwater of
average rainfall

Controle by groundwater by-pass, subdrainage and land-side impermeable walls

Paving the site, Removal of rubble from the roof, Waterproofing
To store all purified water by purificationequipments in welded type tank

"RETAINING" contaminated water

Switch frange type tank towelded type tank

To be responded properly according to
generation of contaminated water, etc.

from leakage

Securing Tank capacity
Ground stabilization, Maintenance of land-side impernmeable wall , Monitoring of groundwater/inside harbor

Treatment for the stagnant water

Reduction of radioactive materials instagnant water up to one tenthCompletion of stagnant water in the buildingsin the buildings
Lowering the level of groundwater/
stagnant water in the building

Maintaining emptied condition of turbinbuildings

Separation of the penetrations between
Units 1 and 2 and between Units 3 and 4

Determination of fuel debris retrieval methods
for the first implementing unit

Start of fuel debris retrieval at the first
implementing unit

Taking required actions in accordancewith the phase of fuel debris retrival

Contaminated water management
in consideration of fuel debris retrieval

Study for consistency between existing circulation cooling system
and PCV circulation cooling systems and monitoring method

Fig. 9 Technical issues and further plan on contaminated water management314) Fuel removal from spent fuel poolsi.

Sectoral target(1) To start removing the fuel from the pool by around
1) FY 2023 for Unit 1
2) FY 2023 for Unit 23) Mid FY 2018 for Unit 33
under the rigorous risk assessment and management and taking measures for safety andsecurity including preventing the disperse of radioactive materials.
(2) By transferring the fuel stored in the Common Spent Fuel Storage Pool to the dry cask at theTemporary Cask Custody Area, the fuel in the spent fuel pools of Units 1 to 4 is to be stored
in the Common Spent Fuel Storage Pool appropriately.
(3) Based on the assessment of the long-term integrity and investigation for future treatment of
the removed fuel, the storage and future treatment methods of them will be fixed around 2020.
ii.

Sectoral Strategy
Risk reduction concept and concrete plan for removing the fuel from the pool
The fuel stored in the pool of the reactor buildings of Units 1 to 34, some of which werepartially damaged by the hydrogen explosion, is to be transferred to the Common Spent Fuel
Storage Pool that needs lower safety management than the pool of the reactor buildings inaccordance with an appropriate and concrete work plan developed depending on the situationof each unit, as soon as possible.
Work schedule for Units 1 to 3 was already specified in the Roadmap, and TEPCO has beenproceeding with their tasks to meet this schedule. Currently, in Unit 1, the building cover had
been removed, wind breaking fence had been installed, and then removal of some fallen rubbles
generated by Hydrogen explosion were initiated under taking measures for prevention ofradioactive dust dispersion. The time to start removing fuel in the pool is targeted for FY2023.
In Unit 2, it is planned to dismantle the upper part of the reactor building in order to install fuelretrieval facilities. Making of opening to have access to the operating floor and installing a front
chamber to prevent dispersion of radioactive material have been implemented, surveillance ofthe operating floor and countermeasures are under way. The time to start fuel removal from thepool is targeted for FY2023. In Unit 3, a cover for fuel removal from the pool was installed in
February 2018. Once started the trial operation for fuel handling equipment, several troubles
have occurred. TEPCO intends to examine and review the start of fuel removal in the spent fuel

In Unit 3, several troubles have occurred after the trial operation of fuel handling equipment is commenced in
March 2018. In addition to investigating the cause and taking the measures, trial operation will be restarted after
the issue on quality management is improved which is thought as a common factor. By giving the highest priority
to safety, TEPCO is examining and reviewing the scheduled target of fuel removal in the pool within November
2018.
4 Removal of fuel from the pool of Unit 4 finished in December 2014.
332

pool which was scheduled in November 2018.
The fuel is also being stored in the pool of Units 5 and 6 reactor building under stableconditions same as a normal nuclear power plant. The Roadmap states that the fuel of units 5
and 6 should be properly stored in each spent fuel pool for the time being and will be removed
them from each pool at when such removal work becomes not to affect fuel removal and fueldebris retrieval work of Units 1 to 3.
Storage plan of removed fuelAppropriate capacity for the fuel in the pools of each unit should be reserved both inCommon Spent Fuel Storage pool and in Temporary Cask Custody Area. For this reason, it isnecessary to expand storage capacity of the Temporary Cask Custody Area systematically.
Decision on storage and future treatment methods
The spent fuel pools is storing many kind of spent fuel such as flawless spent fuel, damaged
one before the accident, and that may be damaged by the fallen rubbles into the spent fuel pool.
Corrosion due to seawater sprayed and injected into the spent fuel pool of Units 2, 3, and 4 at
the accident is another concern. It is necessary to investigate that additional attention for thehandling/storing of such fuels is required compared with that for normal spent fuel.
Storage and future treatment methods for removed fuels from the pools will be decidedaround 2020 based on the investigation results on long-term integrity assessment and treatment
method for them.
iii. Technical issues and future actions for promoting strategies
Removing fuel from the pools<Unit 1>
During removing rubble on the operating floor, countermeasure for preventing falling the fuelhandling machine (FHM) and overhead crane into the fuel pool need to be considered carefully.
Removal of rubble on the operating floor and manipulation of the well plugs need to be carriedout with countermeasure to prevent dust dispersion as well as dose monitoring system to limit
the increase of sky-shine radiation under allowable level.
In addition, appropriate removal method for the damaged fuel before the accident needs tobe prepared.
<Unit 2>
Installing a common container/cover for both fuel removal and fuel debris retrieval, or acontainer/cover exclusively for fuel removal only on the operating floor will be chosen by anappropriate time based on the period of fuel debris retrieval work and fuel removal from the pool.
Also, the scope and method of dismantlement and modification of the above of the operating
floor need to be investigated and established to its work plan based on the results of theinvestigation on the operation floor.
Before removing the fuel from the pool, the exhaust stuck for Units 1/2 will be dismantled.

33

<Unit 3>
Fuel in a spent fuel pool need to be taken out combined with removal of the fallen rubble
on top of the spent fuel. Accordingly, procedure for removing fuel needs to be developed
considering how to remove rubble.
Proper storage of removed fuelFor the deliberate transportation and storage of spent fuel and fresh fuel possessed by theentire site, a fuel transport plan need to be developed taking fuel stored in the Units 5/6 into
account. As well, the storage capacity need to be increased and additional facilities are also
necessary to be installed according to that plan.
Decision on future treatment/storage method
R&D on the long-term integrity of the fuel in the pool which has contacted with seawater orfallen rubble has indicated that removed fuel can be stored safely under the environment ofCommon Spent Fuel Storage Pool for a long period. Also, it was confirmed that the effect of
seawater and scratches by fallen rubble on the fuel is limited for integrity of stored fuel in thedry cask. Furthermore, another R&D showed a perspective that the impact of seawater andscratches by fallen rubble on the fuel is very limited on the treatment of the fuel removed fromthe pool.
In the future, necessity of further study on its long term storage need to be evaluated basedon the inspection/survey results of the fuel taken out from Unit 3, which is experienced thesevere explosion caused by the accident and some of fuel may be damaged by the fallen rubble.
Technical issues and further plans described in this article is summarized in Fig. 10.

34

Fiscal year

2018

2019

2020

2021

2022

2023

2024

2025

On-site work
Technical studies for on-site construction

Unit 1

Rubble removal, etc.

Unit 2

Investigation of operating floor, etc.

Cover installation, etc.

Fuel removal

Dismantlement and modificationof upper part of building, etc.

Plan①

Container installation,

Plan②

Cover installation, etc

Fuel removal

Disassembly of Unit No.1 and No.2 exhaust pipe

Environment
around Unit 2

Measures to prevent sea contamination, etc.
Preparatory work
Unit 3
Fuel removal
Cover installation, etc

Toward construction to place
covers/containers
Selection of retrieval

Study onSelecting plan

Submit/Approval request to implementation plan
/Preparatory work

plan for Unit 2

Procurement of dry cask

Proper storage ofremoved fuelTransfer from Common Spent Fuel Storage pool to Temporary Cask Custody Area

Fuel removal from Unit 5 and 6

Implemented at the extent of rendering no impact
to the works on Unit 1 to 3
Adding dry cask temporary storage

Determination of future treatment and stroring
method of removed spent fuel (around FY2020)
Study forFuture treatment・Study on long-term integrity inconsideration of fuel of Unit 3

storing method
Study for method oftreatment and storing

Fig. 10 Technical issues and further plan on removing fuel from the spent fuel pool355) Other specific measuresi.

Sustaining of reactor cold shutdown status
As for the plant conditions of Units 1 to 3, it is judged that a stable state of cold shutdown ismaintained based on the internal plant data on PCVs, such as radiation dose, temperature,hydrogen concentration, pressure, radioactive substance concentration, etc. To maintain the stablestate in the future, it should be continued to monitor parameters in PCVs and seal nitrogen to
reduce a risk of a hydrogen explosion, while maintaining and improving reliability throughmaintenance and management.
ii.

Radiation dose reduction and contamination expansion prevention all over the power
stationPrevention of sea contamination expansion
The concentration of radioactive materials in the port is below the concentration limit definedin the notification because of the removal of highly concentrated contaminated water in the
trench, installation of the sea-side impermeable wall, covering of the seabed soil, etc. Measures
to reduce the concentration of radioactive materials in the drainage channels that flow into theport, including measures to manage rainwater flowing in from the rooftops of buildings andpaving around the buildings, should be continued.
Regarding contamination of the soil in the vicinity of the harbor, assessing the impact on theocean from a long-term perspective and future environmental restoration, R&D should be
conducted such as to clarify the near-surface nuclide migration mechanism and refine theanalytical models.
Management of gas and liquid waste
Monitoring of gas and liquid waste should be continued and its emission should be closely
controlled to ensure that the concentration limits defined in the Notification is strictly observed.
With this view, proper countermeasures should be taken as their concentrations are made as
low as possible based on a reasonable methods.
Dose reduction through site decontamination
In March 2014, TEPCO formulated “Implementation Policy of Dose Reduction on the Site of
the Fukushima Daiichi NPS" and set target dose rates in stages for each area in the sites toreduce the dose. As a result of these efforts, the target dose equivalent rate of 5 μSv/h wasachieved at the end of FY 2015 in the area that lots of workers work other than the zone
surrounding Units 1 to 4 and the waste storage area. Currently, the area in which it is permitted
to work with general work clothes has increased to 96% of the entire sites. The dose rate should
be maintained below 5 μSv/h and as close as possible to the situation before the accident
ultimately by lowering the target dose equivalent rate in stage.

36

Reduction of environmental impact
Regarding the evaluation of the dose at the site boundary including additional emissions
from the entire site, reducing the effective dose is continued to address after the goal to reducethe value to less than 1 mSv/year has been achieved at the end of 2015 in the result of theefforts stated in the previous clauses and purification of highly contaminated water.
Comprehensive risk review
TEPCO conducted a comprehensive inspection of risk sources that may affect the outside of
the site and announced it in April 2015. As a result, for the radiation sources requiring additional
measures, specific measures were discussed while taking priorities into consideration. They
were reviewed as appropriate reflecting environmental changes, and have been explained andannounced at places such as the local adjustment meeting for decommissioning andcontaminated water management.
Also, the Nuclear Regulation Authority created a target map for reducing the mid-term risk of
the Fukushima Daiichi NPS in February 2015. This Mid-term risk reduction target map, which
has been updated from time to time, is characterized by a risk reduction work process of about
three years emphasizing the presentation of residual risk. In regard to this, TEPCO reported thecurrent approach, issues and responding status according to the further schedule in May 2018.
It is important to continue to reduce and comprehensively grasp the risk sources like this,while taking the positioning and priority in the entire decommissioning project into consideration
for implementing each measure.
iii. Plan for decommissioning measures for nuclear reactor facilities
In the Roadmap, TEPCO should formulate a decommissioning plan of the Fukushima Daiichi
NPS in phase 3 after commencing fuel debris retrieval work, after starting debris retrieval
operations. NDF should provide multifaceted and expert advice and guidance based on the
progress and forecast of the decommissioning, the situation of the reactor buildings, and the trendsof R&D with wisdom and knowledge from around the world.
As for Units 5 and 6, spent fuel removal should be carried out with reference to progress of works
in Units 1 to 4, and then, decommissioning plans should be formulated for Unit 5 and 6.
iv. Concrete efforts toward securing safety
Efforts to ensure work safety
For the work plans that require workers to intervene in a high-dose environment, it is importantto evaluate the environment according to input resources from the viewpoint of "justification andoptimization", aiming to ensure the safety of the working environment as well as suppressing
personal dose. Particularly when the work is “for the first time,” “changed,” or “for the first timein a long time,” it is essential to fully implement work training using a mockup in order to design,
implement and verify effective work procedures and test methods.
Moreover, it is necessary to formulate a detailed work plan for each work step, to takepreventive measures concerning troubles that may occur, and to consider ways to cope with
unexpected situations.

37

In line with the Roadmap, it is stated that measures for industrial accident prevention will betaken and reviewed continuously, medical preparedness will be planned in anticipation ofindustrial accidents, and measures will be taken to reduce occupational risk exposure as muchas possible. It is important to ensure a perfect system of work safety by continuing these efforts.
Efforts for facilities safety
In the Fukushima Daiichi NPS where there are various kinds of work and safety facilities,
special attention to the safety of facilities is also essential. For this reason, measures are
implemented to maintain and improve equipment reliability based on the maintenance plan forevery piece of equipment. Particularly, for equipment vital to securing safety for cooling fueldebris, it is important to continue thorough measures that will be taken to prevent their importantfunction from stopping, not just from the standpoint of equipment but from management andoperation standpoints as well.
Security enhancement
A great quantity of nuclear fuel material is stored in the Fukushima Daiichi NPS. Accordingly,
it requires particular attention to be paid for its security same as a normal nuclear plant,measures to confirm the reliability of each individual, enhance nuclear security training, prevent
unauthorized intrusion into the sites, etc. are being implemented. Continuing with these efforts,
it is necessary to implement appropriate measures for operation to allow accepting the visits ofinspectors.

6) Comprehensive efforts for the decommissioning project of the Fukushima
Daiichi NPS
As mentioned in Chapter 2, in the decommissioning project of the Fukushima Daiichi NPS in the
future, it must be addressed more complex, uncertain challenges over the long term, such as fueldebris retrieval work. Therefore, regarding the efforts of each field listed in 1) to 5), a more proactive,
systematic approach will be needed to solve the challenges rather than fulfilling tasks in a reactive
manner such as those mentioned above. Particularly, the decommissioning of the Fukushima
Daiichi NPS involves great uncertainty, it must be proceeded while always facing project risks likethis. If it has a big difference between information or estimation when the plan developed andanother obtained by progress of work, it may be difficult to conduct works as scheduled originally.
Furthermore, it is important to optimize resource allocation and scheduling while ensuring theconsistency and feasibility of the entire efforts to be promoted concurrently while having
interrelations. Based on this viewpoint, the overall plan of the decommissioning project should beformulated and discussed while setting reasonable intermediate targets from a facility-wide longterm perspective. Because various efforts are performed in parallel manner, it is a significant
challenge how the consistency among works should be ensured.
Furthermore, it is important to optimize resource allocation and scheduling while ensuring theconsistency and feasibility of the entire efforts to be promoted concurrently while having
interrelations. Namely while this complicated and multilayer project should be controlled based on
individual tasks of appropriate scale and control size, the entire decommissioning project should38

make progress comprehensively in consideration of the mutual relationship among the smaller
projects. The overall plan of the decommissioning project should be formulated and consideredwhile assuming reasonable intermediate targets by overviewing the entire site from a mid-and longterm perspective.
Regard to the project risks to sustain stably for entire decommissioning project as this, it isessential to take appropriate responses from the proper implementation of progress management
and fund management of work, while learning from overseas precedent cases.

39

4 Handling critical enablers for smooth operation of the project1) Actions toward improvement of working environment and conditions
The working environment of the Fukushima Daiichi NPS has now been dramatically improved. A
good working environment is the basis for ensuring safe and steady progress of thedecommissioning project of the NPS, which will be carried out over the long term. For example,
TEPCO is improving the working environment infrastructure by consolidating and removing existing
rest stations and setting up alternative rest stations, etc. Moreover, variety of measures are takensuch as management for safety and sanitation, preventing heatstroke, exposure management,dose reduction measures in the site.

2) Concept of securing safety and promotion of cooperation
Because it needs to discuss, in parallel, specific tasks and regulations to be observed in
conducting tasks such as fuel debris retrieval work for which no preceding experience exists in theworld, principle of securing safety should be established according to the situation of the Fukushima
Daiichi NPS. In light of this, NDF, TEPCO, the Agency for Natural Resources and Energy and otherorganizations will cooperate with each other, communicate actively with the Nuclear Regulation
Authority, and take appropriate actions such as presenting policies and observation data related toensuring safety at an early stage.

3) Enforced management structure for steady mid-and-long-term
decommissioning
TEPCO has partly prepared a project structure for various work relating to decommissioning.
However, line operation management and project operation coexist in actual management, leading
to slow decision-making, there is a challenge that it is not necessarily efficient as a whole. For thisreason, it is necessary to shift the organization management to project-oriented management andreinforce the organization and functions to coordinate the projects. At the same time, it is necessary
to enable TEPCO to manage its engineering and make it function, in order to make a structure of
project management work effectively based on a deep understanding of the technical work ofindividual tasks.

4) Developing and securing human resourcesi.

Developing and securing operators and engineers
The decommissioning project of the Fukushima Daiichi NPS requires completely different skills

from the technologies related to the construction and operation of NPSs that TEPCO has
accumulated to date as well. Accordingly, the Decommissioning R&D Partnership Council has
prepared a draft technology map to grasp the overview of necessary technologies anddecommissioning personnel, it is expected for related institutions to utilize it for developing andsecuring human resources.

40

In handling a complex large-scale project like the decommissioning of the Fukushima Daiichi
NPS that involves many related factors , it requires specialized personnel with the ability to manage
projects from a comprehensive perspective, including the consideration of the relationship between
the projects based on the overview of the entire decommissioning process.
ii.

Fostering the next generation to play roles in the Decommissioning of the Fukushima
Daiichi NPS in the future
To carry out R&D activities sustainably for a long period, industry, academia, and thegovernment related to nuclear power should steadily continue efforts for human resources such as
development and securing of future researchers and engineers.
Specifically, the industry and educational institutions should cooperatively continue the activities
to nurture students' understanding of the nuclear power industry and show the attractiveness of theindustry. They should also convey students that the decommissioning of the Fukushima Daiichi
NPS is an extreme technological challenge unprecedented in the world, as well as building andshowing a variety of career paths for researchers and engineers to take part.
Furthermore, in long-term and large-scale projects such as the Fukushima Daiichi NPS
decommissioning, it is essential to develop core personnel for research and development who can
perform scientific and engineering investigation from an academic perspective and personnel witha panoramic perspective (system integrators) who can integrate individual technology seeds into asystem with practical functionality. This activity is being implemented by Essential R&D themes
described next in Chapter 5.

41

5 R&D initiatives
1) Basic policy for R&D
i.

Basic policy
NDF has developed an R&D duties implementation policy based on the NDF Act, and has been

managing a wide range of R&D to support the steady implementation of initiatives technicallyaccording to the Roadmap.
As detailed processes towards the decommissioning will be clarified, the roles of each R&D
player should be more clarified. In this case, it is necessary to arrange the division of roles andresponsibilities between the government and the operator in an appropriate manner in order tosteadily implement R&D results on the decommissioning site. To back up the implementation of
the mid-and-long-term decommissioning project, it is considered to be further expected that the
government andthe relevant research

institutes

shouldestablish centers ofbasic

research/research infrastructure based on a mid-and-long-term perspective. Research institutes
are expected to enhance the technologies required for decommissioning through considerations
on the status of the project and the fundamental R&D activities according to scientific andtechnological issues (needs) regarding the decommissioning.
ii.

Entire perspective of R&D
Various problems exist in the decommissioning of the Fukushima Daiichi NPS, and R&D

activities for solving these problems are being conducted by variety of industrial-academicgovernmental institutions engaged with the Fukushima Daiichi NPS decommissioning R&D
projects

through

the

areas

of

basic/fundamental

research,

appliedresearch,anddevelopment/utilization (Fig. 11). To organically link these activities and efficiently solve the on-site
problems through R&D, NDF regularly holds meetings of the Decommissioning R&D PartnershipCouncil according to the decisions of the Team for Countermeasures for decommissioning andcontaminated water management.

42

43

Administering

National R&D Agency
Plant makers
Electric power Companies, etc.

※８
※９

※７

※３
※４
※５
※６

※１
※２

※８

Commission

Information
sharing※９

Exchange of
researchneeds/seeds

Participation

Project
Management
Operation

Platform of Basic
Research for
Decommissioning

Fukushima Environmental
Safety Center

Okuma Analysis andResearch Center

Request for study
and Support

TEPCO（Member）
NDF,JAEA,TEPCO,
IRID, Plant Makers,
Related Experts, METI,
MEXT

Naraha Remote Technology
Development Center

CLADS

Sector Fukushima R&D

Decommissioning
Strategy Committee
Decommissioning
R&D PartnershipCouncil

MEXT

Adopteduniversities, etc .

Acceleration
Program for Reactor
Decommissioning

Domestic universities,
Research institutes, etc.

Adopteduniversities, etc .

Human Resource
Development andResearch Program for
Decommissioning ofFukushima Daiichi NPS

Foreign
Universities/
Joint
ResearchResearch
Institutes

Foreign
Governmental
Agencies

Cooperation

Administering

Commissioned Research Institutes

Contract/
collaborative
Research

Project
Management
OfficeAssignment

Cooperative
relationship※7

Funding

Steering committee

Center of World Intelligence Project for Nuclear S&T
and Human Resource Development

JAEA

Management
Expenses Grant

SupportNDF

Sharing/planning
R&D information

SupportSupportFig.11. Whole picture of R&D structure of the decommissioning of Fukushima Daiichi NPS (As of FY 2018)

Decommissioning R&D Partnership was established in NDF according to a decision of Team for Countermeasures for Decommissioning and Contaminated Water Treatment.
Bold solid arrow mean supply of R&D and management expenses (except for facilities expense).Light solid arrow means cooperati on. Dotted line arrow means participation in
Decommissioning R&D Partnership Council.
Some institutions including JAEA are at the multiple positions.
Each institution has their own cooperation with foreign institution based on MOU, etc.
R&D activities by other institutions including Central Research Institute of Electric Power Industry are abbreviated.
Among the promotion projects of nuclear energy science technology/human resource development that require collective know -how, the adopted projects up to 2017
were entrusted by MEXT to the trustee, which are not shown in this figure.
Subsidies for the promotion projects of nuclear energy science technology/human resource development that require collective know-how are delivered to JAEA, but expressed
as being delivered to CLADS for the sake of clarity here.
For Decommissioning and Contaminated water treatment subsidy project, NDF drafts the next R&D plan and METI determines it based on the policies on Roadmap and the Strategic Plan and R&D progress.
NDF participates in the steering committee of human resource development promotion project of Nuclear Science Technology that gathers wisdom and intelligence, as a constituent.

Domestic / Foreign Enterprises

Othermakers, etc.
(including
foreignenterprises)

IRID

Subsidized Project Operating Entities

Grant

Project Management
OfficeAssignment

Fund Establishment Organization
Fund for Decommissioning andContaminated Water Management

Funding

Project of Decommissioning andContaminated Water Management

METI2) R&D of decommissioning required for on-site work/engineering
There are two types of R&D activities towards practical use for successfully implementing thedecommissioning of the Fukushima Daiichi NPS: the engineering activities including technologicaldevelopment implemented by TEPCO and the Project of Decommissioning and Contaminated
Water Management carried out by selected subsidiary companies. Especially hereafter, R&D tasks
engineering studies clarified its importance should be implemented timely and accurately.
Specifically, for the time being, R&D tasks are going to be identified according to the progress ofthe preliminary engineering work implemented by TEPCO, and then, it is presumable that the timing
to implement such R&D tasks will be determined through considerations of the project management.
To realize an R&D management system under such project-based schedule, appropriate
information sharing should be carried out under the project management system enforced jointly
by NDF and TEPCO. To this end, TEPCO and NDF should marshal the details of R&D currently inprogress, and R&D tasks required in the future under the project management system in relation
to the engineering schedule, that is, clarifying when the problem must be solved and which projectneeds it.
In this regard, even including implementing the tasks in the Government-led Project ofDecommissioning and Contaminated Water Management, implementation of R&D tasks should beconsidered in line with the basic concept of an appropriate division of roles between the government
and TEPCO according to the substances of the tasks. Specifically, more difficult R&Ds are
considered to need supports by the government.
As specific processes become apparent, it will be required for TEPCO to make efforts to raise
the ratio of technological development to improve the safety and efficiency of the decommissioning
work. Under the Reserve Fund system, it is important to steadily figure out and implement therequired technological development.

3) Enhancement of basic study and R&D infrastructure for the success of thedecommissioning projecti.

Essential R&D Themes and its strategic promotion derived from the needs
To facilitate the Fukushima Daiichi NPS decommissioning project in a safely steady and effective

manner, it is essential to develop mid-and-long-term R&D strategies including scientific andtechnological investigation based on understandings of the principles and the theories. For thispurpose, NDF has built a task force on research collaboration and specified the 6 Essential R&D
Themes that should be preferentially and strategically targeted based on the discussions at theDecommissioning R&D Partnership Council. Thus, the Platform of Basic Research for
Decommissioning was investigated and compiled R&D strategies for the Themes.

44

ii.

Building R&D infrastructure based on mid-and-long-term vision
To make the decommissioning work proceed steadily in terms of technology, it is essential towork on developing R&D infrastructure and accumulating technological knowledge, developing
generic technologies and collecting basic data, including the Essential R&D Themes, building up
research centers, facilities and equipment, and human resource development.
The building for international research collaboration of JAEA/CLADS has opened in April 2017
in Tomioka-machi, Fukushima prefecture. According to a proposition by NDF, the Center of WorldIntelligence Project for Nuclear S&T and Human Resource Development by the Ministry of
Education, Culture, Sports, Science and Technology (MEXT) is implemented under the structure
centered on JAEA/CLADS from the newly adopted issues since FY2018.
It is also important to develop research infrastructure of hardware. JAEA put the Naraha Remote
Technology Development Center (Naraha-machi, Fukushima Prefecture) in service in April 2016,
Fukushima Prefectural Centre for Environmental Creation where Fukushima Prefecture, JAEA, andthe National Institute for Environmental Studies have their offices (Miharu-machi, Fukushima
Prefecture) opened in July 2016, and JAEA opened the facility management building of the Okuma
Analysis and Research Center (radioactive material analysis and research facility) (Okuma-machi,
Fukushima Prefecture) in march 2018. R&D infrastructures aiming at the mid-and-long-term vision
are being set up mainly in Fukushima Prefecture.

45

6 Enhancement of international cooperation
1) Significance of international cooperation
In recent years, nuclear reactors and nuclear fuel cycle facilities, constructed in the development
age of nuclear power, are coming to the end of operating life and these decommissioning havealready been progressing in the world. There are three major nuclear reactors caused severe
accidents: Winscale Unit 1 in UK, Three Mile Island Unit 2 in the US, Chernobyl Unit 4 in Ukraine.
These facilities have taken stabilization and safety measures for a long time. Furthermore, there issignificant uncertainty in the management of various radioactive substances in past nuclear
facilities called “legacy sites” where are located in the UK, US and France etc. In these sites, thereis implemented decommissioning and environmental remediation for a long-term. For this reason,these countries have been challenging to issues such as technological difficulties called “unknown
unknowns” (unknown issues that even uncertainty level is not known), project management over
several decades, and securing of large amount of funds.
In order to make steady progress on decommissioning of the Fukushima Daiichi NPS, it isimportant to learn the lessons of decommission experience from accident reactors and legacy sites
in the world as well as actively utilize the world’s best technologies and personnel resources. In
addition, to secure and maintain understanding and support from international communities, it isalso important to engage in decommissioning with open to international societies.
The decommissioning of the Fukushima Daiichi NPS is expected to offer the opportunity ofdevelopment for front-line science and technology and to become a source of innovation. For
instance, dose distribution measurement in the buildings of Unit 1 and 3 by using the multicopter(RISER), that enables three-dimensional dose evaluation developed in UK, has made someachievements, as a result of testing its applicability in the Fukushima Daiichi NPS. In this way,technologies and knowledge acquired through decommissioning of the Fukushima Daiichi NPS canbe beneficial for the countries engaging in decommissioning.
The international institutions such as IAEA, Organization for Economic Co-operation andDevelopment/Nuclear Energy Agency (“OECD/NEA”) have a role of contribution to design theinternational standard, share the knowledge and experience among nations, and form theinternational common perceptions for decommissioning. To proceed decommissioning of the
Fukushima Daiichi NPS in an open manner, it is important to participate in the activities of these
institutions. At the same time, as Japan participates in the discussion for design the international
standard, based on the experience of the Fukushima Daiichi decommissioning, it leads to sharethe experience with memberships of the institutions. It is expected to fulfill the Japan’s responsibility
to the international society.

462) Facilitation of international cooperation activities
i.

Enhancement of partnership with overseas decommissioning agency
Concerning to long-term process of the Fukushima Daiichi NPS decommissioning, it is necessary

for cooperation with overseas decommissioning agencies to engage focusing on creating
continuous partnership not as transient. Especially, the decommissioning of legacy sites will serve,
as a model for approach preceding to the Fukushima Daiichi NPS decommissioning, in many
knowledge in accordance with technology and management.
Decommissioning for legacy sites is promoted by decommissioning institutions that isestablished officially by each country because it requires the expertise, concept and newtechnologies, etc. to differ from the operation/maintenance for nuclear reactor or nuclear fuel cycle
facility. Therefore, it is important for NDF to reinforce a continuous partnership with these institution
such as Nuclear Decommissioning Authority (NDA), Commissariat a l’energie atomique (CEA),
United States Department of Energy, Office of Environmental Management (DOE/EM) based on
government-level framework. TEPCO should establish a long-term partnership with overseas
decommissioning operators, and these should be broad cooperation-based.
ii.

Integrating and utilizing wisdom and knowledge from around the world
In regard to decommissioning of the Fukushima Daiichi NPS, wisdom and knowledge fromaround the world that our country should obtain is implemented with a variety of approaches suchas system/policy, providing strategy, project plan/operation, ensuring security, regional
communications, and so forth, not only in technical aspect but operational aspect. Up until now,there are signs to support decommissioning of the Fukushima Daiichi NPS by international society,and several kinds of supports have been given by overseas governmental institutions and experts
including DAROD project led by IAEA and collaboration projects promoted by OECD/NEA. It isdeeply appreciated to these supports.
Decommissioning is implemented by many companies and decommissioning operators under
the contract in both domestically and internationally. The decommissioning market is expanding
worldwide. In order to use the highest level of technologies and human resources in the world, itshould be updated the latest status.
iii. Dissemination to global society
It is essential to promote decommissioning in an open manner to international society forprevention of reputational damages as stated in the Section 7 and it should strengthen to distribute
easily understandable information, for helping accurate comprehension from international society.
Consequently, NDF takes dissemination of information about the situation of the Fukushima
Daiichi NPS decommissioning globally through holding side events of IAEA General Meeting andgiving speeches at key international meeting. Also, International Forum on the Decommissioningof the Fukushima Daiichi NPS is held in order to report information about the situation of the47

Fukushima Daiichi NPS decommissioning to the world and to take effort to communicate with local
communities.

3) Close cooperation with relevant domestic organizations
As stated in Chapter 2), concerning international cooperation, it is promoted that relevant
domestic organizations build and strengthen partnership with foreign organizations in accordancewith the role of each organization. It should be shared the knowledge and human connections
obtained through these activities to ensure consistency of international cooperative activities inJapan and implement effective international cooperation. Therefore, the relationship of relevant
domestic organizations should be further enhanced.

48

7 Local community engagement and further enhancement ofcommunication
1) Approaches for local community engagement and further enhancement ofcommunication
For implementing decommissioning of the Fukushima Daiichi NPS steadily, Local community
engagement is the major premise, and it should be seeking for decommissioning to contribute to
the restoration in local communities while trying to establish trustful relationships closely with theregion.
Communication is the foundation to establish trust relationship with the region, and it is a starting
point to listen to the voice from various standpoints including local communities sincerely.
Particularly, it is important to respond to their questions about the project/planning anddecommissioning activities as well as anxieties against safety or risk management. While not only
providing information on progresses of approach to safety measures and relevant work and onradioactive safety appropriately but also communicating interactively, further decommissioning
should be proceeded by establishing common understandings about risk reduction policy. On thefoundation of communication like this, it is necessary to co-exist with the regions throughdecommissioning and its relevant economic activities in contributing to the restoration andrevitalization of the region.

2) Actual effort for better communication
As fuel debris retrieval work moves into full swing, it is necessary to consider and put into practicea further well thought-out communication method under proper collaboration of the relevantorganizations.
The Japanese government is to engage polite communication by holding “The Fukushima
Advisory Board” or by preparing the videos or the brochures “The important story ofdecommissioning process” that explains current decommissioning status.
NDF hosts International Forum on the Decommissioning of the Fukushima Daiichi NPS annuallyfor providing information and vigorous dialogue about decommissioning with the local citizens aswell as prepares a brochure “Hairo-no-iroha“ that can express decommissioning in plain words.
NDF is to continue vigorously to promote interactive communication activities like these and to takeall of the local voice sincerely.
TEPCO is to work on appropriate information dissemination by publishing web contents and“Hairo michi” as a periodic magazine as well as establishing the decommissioning communication
center in November, 2017. Moreover, TEPCO promotes to accept observers into the Fukushima
Daiichi NPS, and plans to expand observers and enrich the scope of visit further in the future.

493) Further spread of communication and measures to reputational damages
There is a possibility that a reputational damage may be caused by being anxious even if therisk does not become obvious. Moreover, it is pointed out that even seven years have passed after
1F accident, the image, immediately after the accident, is not being wiped off and it has been settled.
When delays in responding to reputational damages or troubles on decommissioning work occur,
it may produce a vicious cycle such as downgrading evaluation from society for addressing
decommissioning then it causes the further delay of activities. In order to prevent from a vicious
cycle like this, it is the most important to promptly reduce existing risks while making efforts forproper safety management. Besides, as for measures to be taken to prevent reputational damages,
it is necessary to enrich communication with local residents, media, market participants, anddistributors as well as consumers including overseas.

50