Nuclear Damage Compensation and Decommissioning Facilitation Corporation

1-2“The Strategic Plan”
for
Decommissioning of Fukushima Daiichi NPS
Overview of Strategic Plan for Fuel Debris Retrieval

Jun 30, 2015
Nuclear Damage Compensation &Decommissioning Facilitation Corporation(NDF)©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

1st Version of the Strategic Plan Released!
Contents

1. Introduction – Who is NDF?
2. What is Strategic Plan?
3. Guiding Principles for the Strategic Plan
4. Strategic plan for fuel debris retrieval
5. Strategic Plan for waste management~ 200 Pages

6. Approach to the R&D and its overall program
7. Future Development of the Strategic Plan
You can get pdf version of the Strategic Plan at NDF web site below!
http://www.dd.ndf.go.jp/ddwp/wpcontent/themes/theme1501/pdf/SP2015_20150623.pdf
http://www.dd.ndf.go.jp/ddwp/wp-

content/themes/theme1501/pdf/SP2015_20150624_en.pdf
2©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Establishment of Nuclear Damage Compensation &Decommissioning Facilitation Corporation (NDF)
After December 2011, the Government of Japan developed a structure toensure the TEPCO’s decommissioning process based on the master plan
described in the Mid-and-Long-Term Roadmap (“Roadmap”) determined by
the Government.
Government

TEPCO

Determine Roadmap(Developed in December 2011, revised in June 2013)
Dec 2013
Dec 2011[2
years later][Roadmap development]
Stabilizatio
n activities

Dec 2021[10 years later]

Ensure the decommissioning process.

[30 to 40
years later]

Phase 1

Phase 2Phase 3A period until thestart of fuel removalfrom the spent fuelpool

A period until thestart of fuel debris
retrieval

A period until the endof thedecommissioning of
all of Units 1 to 4

Source: TEPCO’s website

Enhance the support structure so that TEPCO ensures thedecommissioning process under the leadership of the Government.

Nuclear Damage Compensation & Decommissioning Facilitation
Corporation was established on August 18, 2014. (Nuclear Damage
Compensation Facilitation Corporation was reorganized.)3©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Relevant Organizations involved in Fukushima Daiichi Plant
Decommissioning & Contaminated Water Management
Japanese government
Policy making and progress management• Approve the Roadmap• Progress management of urgent issues suchas contaminated water management

TEPCO (D&D Engineering Company)
Progressmanagement
ReportReportPresent
key issues

Implementation of decommissioning work

• Remove fuels from spent fuel pools• Manage contaminated water (installation of additional tanks,
water purification, rainwater management)• Store/manage rubbles, wastes, etc.
• Ensure safety/quality, improve work environment, etc.

ReportAdvice/Guidance

NDF
Formulation of strategy and provision of technicalsupport

ProvideR&D
budgets

1. Develop a mid- and long-term strategy
2. Provide technical support for progress management of key issues
3. R&D planning, progress management
4. Reinforce international cooperation

Report/Submit action
planSupervise/
review

Share progress and issues
R&D organizations-International Research Institute for
Nuclear Decommissioning (IRID)-Japan Atomic Energy Agency (JAEA)
Implementation of R&D projects

Nuclear Regulation Authority (NRA)
Safety regulation

4©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Development of “The Strategic Plan”
As an organization of experts in a variety of technological fields, NDF
develops a mid-and-long term technical strategy called “The Strategic Plan”
through advices with external experts.
● Technology experts in NDF’s decommissioning office(about 30 experts)‐ Plant engineering‐ Robotics‐ Civil engineering and architecture‐ Materials, analysis, monitoring‐ Fuel and nuclear reactor engineering● Experts from external organizations (universities,
JAEA and other research institutions)<Decommissioning Strategy Board>
1st Aug. 21, Thu
6 th Jan. 28, Wed
2nd Sep. 30, Tue
7 th Feb. 23, Mon*
3 rd Oct. 28, Tue*
8 th Mar. 26, Thu
4 th Dec. 4, Thu
9 th Apr. 16, Thu
5 th Jan. 6, Tue* With the participation of fourinternational special advisors.
<Expert Committee>
・Fuel Debris Retrieval Expert Committee
1st Oct. 20, Mon
4 th Jan. 19, Mon
2nd Nov. 26, Wed
5 th Feb. 13, Fri
3 rd Dec. 22, Mon
6 th Mar. 18, Wed
・Waste Management Expert Committee
1st Nov. 26, Wed
4 th Feb. 25, Wed
2nd Dec. 25, Thu
5 th Mar. 30, Mon
3 rd Jan. 26, Mon
Expert-level intensive discussions held
repeatedly among ANRE, TEPCO and IRID
under the lead of NDF on specific Issues

5©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Purpose of the Strategic Plan and Relationship with the
Mid-and-Long-Term Roadmap (Roadmap)
Goals and policies presented by the Government
Roadmap
Key elements of strategies, policies and plans

revised and updated
by the Government

determined by the Government1)Strategy－Provides an approach to conducting activities andmaking decisions and sets priority in achieving the goals
2)Strategic specification for the implementation of thestrategy－Specific policies and requirements for conducting
activities and making decisions

Strategic Plan
developed by NDF(2015 Technical Strategic Plan for
Decommissioning of Nuclear
Power Plants of the Fukushima
Daiichi NPP, Tokyo Electric Power
Co., Inc.)

3)An integrated plan to implement the strategy－An integrated plan for conducting field work andresearch and development

Delivery of Decommissioning
by TEPCO and research institutions(field work, engineering, R&D)

Implementation plans
by TEPCO andresearch institutions
6©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Background of Development of Strategic Plan
Reason why NDF developed Strategic Plannow!
 Changes of Situation

 Response to Uncertainty
 Response to Severe Site Situation
 Awareness of Time Axis
 Sharing the Strategy
7©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Guiding Principles for the Strategic Plan
 Principle
 The decommissioning of the Fukushima Daiichi Nuclear Power Plant is
a continuous risk reduction activity to protect people and theenvironment from the risk of radioactive materials, resulting fromsevere accident.
 A risk reduction strategy along a mid- to-long-term timeline will be
designed in the Strategic Plan.

 5 Guiding Principles for Risk Reduction
 Principle 1: Safe Principle 2: Proven Principle 3: Efficient Principle 4: Timely
 Principle 5: Field Oriented

Reduction of risks caused by radioactive materials*
and work safety(*Environment impact and exposure to workers)
Reliable and flexible technology
Effective utilization of resource(human, capital, money, and space etc.)
Awareness of time axis
Emphasize actual place, actual parts and actual
situation
8©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Risk Reduction in Strategic Plan(i) Risk of radioactive materials
 Risk = Potential effects x likelihood ofloss of containment function(ii) Potential effects
 Potential effects = level of activity x
physical state (solid, liquid or gas)(iii) Likelihood of loss of containment
function Likelihood of loss of containment
function = possibility of occurrence ofthe factor x vulnerability of the
facility

Potential effect s(Hazard potential)

Risk Reduction

Fuel debris

Spentabsorption
vessels

Risks to be addressedsafely, effectively andcarefully with thoroughpreparations&
technologies to realize
more stable condition

Risks to be addressedon a long-term basis
Radioactive
solid wastes

Fuel inpool
Risks to be addressed as
expeditiously as possible
Contaminat
ed-waterin buildings,
tanks andtrenchesSpentsludgeLikelihood of loss of containment function(ⅳ) How to reduce risk
 Move radioactive materials to a safer and more stable facility.
 Reduce potential effects
 Decay of radioactivity and change in the physical state Reduce the likelihood of loss of containment function
9©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Logic Tree Diagram Regarding Risk Reduction(Summary)
Minimizing risk of radioactive materials

Risks to be addressed as
expeditiously as possible

Contaminatedwater

Risks to be addressed safely, effectively andcarefully with thorough preparations &technologies to realize more stable condition

Fuel in pool

Fuel debris

Risks to be addressedon a long-term basis

SecondarywasteRadioactive
Solid waste

Chapter 3

Fuel Debris Retrieval–



Risk reduction offuel debris

Risk reduction ofwaste

Chapter 4

Chapter 5

Develop a workable scenario for fuel debris retrieval assuming several methods (submersion, dry) and a
combination of the methods, taking into account the status of each Unit.

Waste Management–

Develop a policy for storage management, processing and disposal from a mid-to- long-term perspective,
based on the principles for safe waste disposal and appropriate waste processing.

10©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Structure of Strategic Plan for Fuel Debris Retrieval
Chapter 4(Objective)
Reduction of fuel- debris risk

Fuel debris retrieval and safe
storage in the site withcareful preparation promptly(In the future)

Maintenance of stable fueldebris condition until the
retrieval
Maintenance of
reliable safety
facilities

Criticality
control

Cooling

Fuel-debris safe storage
after containment andtransfer

Safe fuel debris
retrievalContainment

CanisterdesignTransfersystemStoragesystemFuel-debris processing
and disposal

Accountability
systemTechnical requirements for fuel-debris retrieval methods
Ensuring safety during thefuel-debris retrieval works

Understanding of fuel-debris
amount, location, characteristics
and FP distribution

Estimation Estimation Estimation bybyby analysis findings andinvestigation
experiment

PCV andbuilding
integrity

Criticality
control

Cooling

Containment

Radiation
protection

Fuel-debris
retrievaloperation
Industrial
safetyEnsuringbuilding
container andworking area

Retrievalequipment

Accessibility
to fuel debris

11©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Status of Plant Investigation and Estimated
Fuel Debris Location
Unit

Plant investigation situation

Estimated fuel debris location

Unit 1

 The D/W water level is approx. 3 m from the RPV
pedestal floor.
 S/C is mostly filled with water.
 The leakage from the sand cushion piping was
confirmed.
 The leakage from the expansion-joint cover of thevacuum break line connected to the W/W venting
piping was confirmed.
 Hot dose rate (several Sv/h) spot in the southeast
area of the reactor building 1st floor.

 Almost all molten fuel dropped down to the
RPV lower plenum and no fuel debris
remains in the core.
 The dropped fuel debris into the lower
plenum dropped down to the RPV pedestal
bottom.
 The dropped fuel debris in the pedestal
bottom flew outside of the pedestal (probableattack to the shell).
 Some molten fuel dropped to the RPV lower
plenum and on the pedestal floor, and theremaining stays in the core (no fuel debris
estimated outside the pedestal).

Unit 2 The D/W water level is approx. 30 cm from the RPV
pedestal floor.
 The S/C water level is close to the center, which isalmost the same water level to that of the torus.
 There is no evidence of leakage in the torus upper
section.
 The photo of RPV pedestal inside taken from theopening confirms the structure of RPV lower region,
which shows that the vessel failure will be not solarge.

Unit 3 The D/W water level is approx. 6.5 m from the RPVpedestal floor. (estimated from the pressure
differential of D/W and S/C)
 S/C is mostly filled with water.
 The leakage from the expansion-joint of the main
steam piping D was confirmed.

 Some molten fuel dropped to the RPV lower
plenum and on the pedestal floor, and theremaining stays in the core (no fuel debris
estimated outside the pedestal).

12©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Methods of Fuel Debris Retrieval according
to the Water Level inside of PCV
Full submersion
methodSubmersion
methodPartial submersion
methodDrymethodWater level up to
the reactor welltop

Water level overthe fuel-debris
location

Water level lower
than the upper
fuel-debris location

No water and all
fuel-debris is open
to the air

13©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Options for Fuel Debris Retrieval Method
Considered PCV Water Level and Access Direction
Access direction
Top
Side Bottom
Full submersion
Submersion
Waterlevel Partial
submersion

a.
b.

c.

Dry

Methods to be focuseda. Submersion method (including full
submersion)b. Partial submersion – top entry method
c. Partial submersion – side entry method: Possibility of waterflowing out from theopenings: Difficulty of constructing
new access route: Difficulty of evaluating
cooling performance

Methods to be focused wereselected with due considerationof features of the water level andthe access direction
Note: The partial submersion method withside access has a possibility of waterflowing out from the access openings.

14©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Three Methods of Fuel Debris Retrieval to be focused

Submersion method
Image on condition that theremoval of core internals
above fuel debris has finished.

Partial submersion Top entry method

Partial submersion Side entry method

Image on condition that theremoval of core internals
above fuel debris has finished.

Image on condition that RPV
pedestal exterior component
inside PCV and the interference
have been removed.

15©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Fuel debris retrieval method scenarios and retrievable
locations of fuel debris
Location of debris where
The retrieval method is feasible

MethodScenario

SubmersionTop entry

PartialSubmersionTop entry

PartialSubmersionSide entry

Inside RPV

Inside RPV
pedestal

Outside RPV
pedestal

（1）

○

―

―

OK

OK

NG1

（2）

―

○

―

OK

OK

NG1

（3）

―

―

○

NG2

OK

OK

（4）

1)

―

2)

OK

OK

OK

（5）

2)

―

1)

OK

OK

OK

（6）

―

1)

2)

OK

OK

OK

（7）

―

2)

1)

OK

OK

OK

The above numbers 1) and 2) indicate the order ofprocedure.

1: Retrieval of fuel debris outside the RPV pedestal will be difficult if only
the Top entry method is used.
2: Retrieval of fuel debris inside the RPV pedestal will be difficult if only
the Side entry method is used.

©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Technical Challenges of Fuel Debris Retrieval Methods
Technical
Requirements

Submersion Method

Partial Submersion
Method

1. Structural Integrity☆ Load by flooding and Aging〇

2. Criticality☆ Sub-criticality at Water Level
Increase〇

3. Cooling〇☆ Debris Coolability by Air

4. Containment☆ PCV Repair & Water Level
Control☆ Dispersion of Radioactive
Dust◎ Dose Reduction in R/B☆ Shielding of Fuel Debris◎ Dose Reduction in R/B〇〇◎ Repair & Maintenance☆ Radiation Resistance◎ Repair & Maintenance

8. Accessibility to Debris◎◎

9. System & Work Area〇〇

10. Canister, Transfer, Storage◎◎

5. Radiation Protection
6. Industrial Safety
7. Retrieval Equipment☆ : Critical Challenges for the Method, ◎ : Common Important Challenges for both Methods〇 : To be confirmed

17©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Decision Flow for Selection of Fuel-debris Retrieval
Method Scenario
Investigation

Identificationof condition

Feasibility
evaluation of
the retrieval
methodEngineering
estimation fromplant parameters

Investigation
by muondetection

PCV internal
investigation

Experimentusing simulated
debrisKnowledge on
past accidents
and researches

Investigation on
condition of R/B
contamination

Estimation based on
accident progression
analysis codeevaluation of dose
reduction required
areas

Comprehensive evaluation on theconditions of fuel debris and FP
Dose evaluation
inside PCV/RPV

Understanding onplant condition
Full submersion/
Submersion method
Structural
Maintaining
integrity of
subcriticalstate
PCV and R/B

Partial submersion
methodRadiation resistance of Shielding against
Impact of dust
visual and measurement high radiation
dispersed to theequipment
outside of R/B

PCV repair andestablishment of water level
control system

Feasibility of Full submersion/
Submersion method

Impact evaluation to
the retrieval work

Impact evaluation on
workers and environment

Location offuel debris

Accessibility to the
Ensuring accessibility ofequipment forAccess to the R/B by dose reduction
maintenance and at fuel debris
measurestimes of troubles

Development ofequipment/devices forfuel debris retrieval

Collection/transfer/storage system
for fuel debris

Feasibility Partial
submersion method

Narrowing down the applicable scenario(consideration on accessibility)

Scenario
evaluation

Evaluation of scenario to befocused based on theFive Guiding Principles

Concept onrisk reduction

Scenario to be focusedfor each unit

18
©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Road towards Fuel Debris Retrieval
Start fuel debris retrieval

Selection of
retrieval method

High

Fuel debris
Retrieval work

Decision of
methodPreparation work
Equipment
SystemPerformance Guarantee

Mock up and training

Practical application/verification test

Technical
Maturity*1(TRL)

Critical technology
Important performancerequirements

Basic/detail design

Element test

FS/Concept design
Prioritization

Concept study
Screening

Low

Concept
investigation

SafetyResource
Site

Understanding the plant and reactor conditions

Prerequisite*1 The vertical axis does

not represent theindividual technology but
an image of the technicalmaturity of the overall
retrieval system

Time

Safety requirement (regulatory requirement)
Securing accessibility (Decontamination, etc.)

19©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Overview of R&D activities related
to Decommissioning of Fukushima Daiichi NPPs
 It is important to facilitate interaction and communications among
researchers and engineers involved in a series of R&D initiatives.

TEPCO

METI
- Decommissioning and contaminated water
management Program (subsidy for R&D projects) etc.

Practical application- Onsite needs/
requirements- Regulatory
requirements
Application development - Performance
guarantee

IRID

JAEA
- Fundamental and basic researchby government funding

JAEA
Fundamental
Universities/Research Institutes research

Knowledge
researchers

Basic research
MEXT- Fundamental research and HRD program- Basic founding- New idea forbreakthrough- HRD/ education-

Specific researchfacility/equipment
Fundamental data

- Application of new
Technologies/system- Equipment anddevicedevelopment- Demonstration- Data for safety20©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Viewpoints for R&D Plan Review for Next Phase
1.

2.

3.

Identify issues, through the confirmation and review
process of ongoing R&D projects taking into account latest
status of Fukushima Daiichi NPP.
Identify and prioritize R&D topics to be addressed, throughthe course of developing the “Strategic Plan.”
Propose individual R&D project plan for the forthcoming
term, including the efforts for new and additional issues,
based upon the above two steps.

（Step 1）
Review ongoing R&D projects, based on
the latest status of onsite（Step 2）

（Step3）

Identify prioritized R&D topics, throughthe development of the “Strategic Plan”,(including the degree of importance anddifficulty of required technologies andsolutions)

Identify
Issues

Propose R&D
21 forproject plannext phase21©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Next Phase R&D Plan Fuel debris retrieval Decontamination and dose reduction

 Development of remote decontamination technologies & comprehensive dose reduction plan

 Water leakage prevention from PCV

 Development of technology to repair leaks and water stoppage of PCV
 Full-scale test for repairing leaks from PCV and water stoppage of PCV

 Internal investigation

 Development of technology to investigate the inside of the PCV
 Development of technology to investigate the inside of the RPV
 Sophistication of internal investigation using accident progression analysis and actual unit data Development of technology to detect fuel debris in the reactor (Muon)

 Fuel debris retrieval method

 Technological development for fuel debris retrieval and internal structures
 Technological development for collecting, transferring and storing the fuel debris Technological development for integrity assessment of RPV/PCV Technological development for fuel debris criticality control

 Fuel debris analysis

 Understanding of fuel debris properties, using simulated debris and accrual debris analysis

22©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Future Development of the Strategic Plan
2014 FY△○ Strategic Plan
development/followup/revision2016 FY

2015 FY

2017 FY & onward

The Strategic Plan is a living document !

■Initial plan■

Revision■

Revision

Revision as
appropriate

Requirements for
scenario・Technical feasibility
・Ease of field work
・Assurance of safety
・Risk assessment
Fieldwork/investigation
conducted
Products of research &development (dataacquisition,assessment method,etc.)

Example: a method for water leakage stoppage, integrity, a method for debris retrieval, fueldebris detection, waste-related activities

23©Nuclear Damage Compensation and Decommissioning Facilitation Corporation