The 3rd Japan-Russia joint forum for education and research

Overview of IRID R&Dfor fuel debris retrieval technologies
at Fukushima-Daiichi
20 th Feb. 2020

Naoaki Okuzumi
International Research Institute for Nuclear Decommissioning(IRID)The results are obtained under the Subsidy Project of Decommissioning and Contaminated Water
Management granted by the Ministry of Economy, Trade and Industry.
Unauthorized copy and reproduction prohibited.
©International Research Institute for Nuclear Decommissioning

1©International Research Institute for Nuclear Decommissioning

Contents
1. Introduction
2. R&D for Investigation inside PCVs
(1) Results of completed investigation(2) R&D for next investigation
3. R&D for Fuel Debris retrieval technologies

Contents
1. Introduction
2. R&D for Investigation inside PCVs
(1) Results of completed investigation(2) R&D for next investigation
3. R&D for Fuel Debris retrieval technologies

Outline of IRID
1. NameInternational Research Institute for Nuclear Decommissioning(IRID)
http://www.irid.or.jp/en/

R&D

2. Date of Establishment
August 1, 2013

IRID

3. Membership (18 organizations)International
2 Research Institutes
Entities
JAEA etc.
4 Manufacturers
ToshibaESS, Hitachi-GE,MHI etc.
12 Electric Utilities, etc.
TEPCO Holdings etc.
4HRD

©International Research Institute for Nuclear DecommissioningRole of IRID
R&D for decommissioning of the Fukushima Daiichi NPS,
with a view to strengthening the foundation of nuclear
decommissioning technologies.

EstablishmentofGovernment(METI)
Mid-and-long Term
Roadmap

TEPCO Holdings(1F D&D Eng. Company)
Decommissioning ofFukushima Daiichi NPS

IRID

NDF

R&D
implementation

Strategy planning
R&D planning

Fund

Nuclear Regulatory Authority
5©International Research Institute for Nuclear Decommissioning1 .R&D for Fuel Removal from Spent Fuel PoolEvaluation on Long-term Integrityof the Fuel Assemblies Removed from Spent Fuel Pool

Completed in
March 2016

2 . R&D for Fuel Debris Retrieval
Technology for
Decontamination and Dose
Reduction

Remote-operated
Decontamination
Technology in R/B
Completed in March 2016

Repair/Water
StoppageTechnology
For PCV Leakage

Seismic
Resistance
Assessment

Completed in
March 2017

Completed in
March 2018

Technologyfor PCV

Completed in
March 2018

Full-scale testof RepairTechnology for PCV
LeakageCompleted inMarch 2018

Fuel Debris Retrieval Technology

Corrosion
ControlTechnologyin RPV/PCVWater
Circulation

Full-scale Test
For PCV Water
Circulation
Technology

Technology forProceeding
Process Methodsof Radioactive
Waste

Technology for

Treatment andDisposal of Solid
Radioactive
Waste

Completed in March 2019

＜Ensuring Stability＞

Technology for
Environmental Improvement

3 .R&D for Radioactive Waste

for RPV/PCV＜Fuel Debris Retrieval＞

Fundamental
Criticality
Technologies
Fundamental
Control
For
Retrieving
Technologies
forTechnology for
FuelDebris
and
Small
NeutronFuel DebrisInternal
Detector
Retrieval
Structures
Completed inCompleted in March 2019
March 2019
Completed inInternal Investigation/Analysis Technology

September, 2018

Development of＜Direct Investigation＞
Investigation
Technology＜Indirect Investigation＞
Technology
For Retrieving
Investigation
Fuel Debris/
For Inside RPV
Fuel Debris
TechnologyReactor Internals
Detection
For inside PCV
Fuel Debris
TechnologyDust Collection
Sampling
For RPV
Completed in March, 2018
System forTechnology
Technology forCompleted inRetrieving Fuel
DetailedJuly, 2016
Debris andCharacterization
Investigation
ReactorInternals
Upgrading
And Analysis of
Of inside PCV
For Identifying
Fuel Debris
Conditions
Completed in March 2019Technology for
Insides theCollection,
On-sitereactorTransfer
On-siteVerification
And Storage ofVerification
Through X-6©International Research Institute for Nuclear Decommissioning
Completed in
Fuel Debris
of Deposits
March, 2018

Penetration

Contents
1. Introduction
2. R&D for Investigation inside PCVs
(1) Results of completed investigation(2) R&D for next investigation
3. R&D for Fuel Debris retrieval technologies

Investigation of inside PCV by using Robots
Investigation of outside the pedestal (Unit 1)

Investigation of inside the pedestal (Unit 2)○Shape-changing robot(B1,B2 investigation)○Remotely operated crawler robot forinvestigation (A2 investigation)

When driving
thenarrow part
狭隘部走行時DuringDuringinvestigation
investigation
Additional
lighting

Advancing
direction

Rear camera andlighting

Crawlers(twoCamera for guide pipe units)

Duringinvestigation

advancement

Shape changing

Crawler

Front camera and lighting

CRD rail

Thermometer During

調査時

investigation
Investigation of inside the pedestal (Unit 3)
Camera forinvestigation

Dosimeter(Note) The robot for B1
investigation is shown in theabove photos

Thrusterfor upanddown

Thruster○Hanging camera
for drivingon extension rodLight○Submersible Crawling Robot

Front camera

8Unit 2 investigation: Pedestal Floor

Pedestal floor and wall
Fuel debris? and a fuel assembly handle

A photographing
place

Bottom of the Unit 2 PCV(An overhead image)

99©International Research Institute for Nuclear Decommissioning

Contact with Deposits (Unit 2)

Investigation date: Feb.13, 2019

◼ The properties of the deposits (hardness and fragility, etc.) that were observed on thebottom of the pedestal in Unit 2 were unknown, therefore it is important to understandthe mobility beforehand.
◼ It is considered that the investigation unit used in January, 2018, will be modified, and themechanical force will be added to the deposits to observe the behavior of the deposits.
Tip bend
control unit

Cable drumIsolation
valve

Extendable concentric
cylinders withdifferent diameters(extendable pipe)

Guide pipe

PCV penetration
pipe (X-6penetration)

Alternativeshield

Pedestal

Platform
Control Rod DriveCable

ModifiedLED light
Camera(withinner camera)

Investigation unit
used in January, 2018

Finger(with drive mechanism)

Image of modified investigation unit

Concept diagram of Unit 2 PCV internal investigation using the guide pipe

100©International Research Institute for Nuclear Decommissioning

Contact with Deposits (Unit 2)

Investigation date: Feb.13, 2019

The investigation report is provided by Tokyo Electric Power Company (TEPCO) Holdings, Inc.
©International Research Institute for Nuclear Decommissioning

Contents
1. Introduction
2. R&D for Investigation inside PCVs
(1) Results of completed investigation(2) R&D for next investigation
3. R&D for Fuel Debris retrieval technologies

Boat Type Access Device◼ A boat type access device has been developed, which
can move on a wide range of the water surface in the
primary containment vessel (PCV).
Guide ring

A clockwise basic route

Example: Guide ring installation• Diameter: φ25cm• Length: Approx. 1.1ｍ
• Thrust: Over 25NAppearance of the boat
type access device

Above ground floor path

Guide ringOperation line of the device©International Research Institute for Nuclear Decommissioning

Unit１: Boat Type Access Device◼ The 6-kind of boat type access/investigation device with submersible function will be prepared.
Installation items

Work flow (image)

Install device
Seal box device

Access/investigation
deviceGuide ring installation

Installation
cable

Waterlevel

Installation for cableentanglement prevention

Guide ring

Deposit

Visual observation
Confirmation of PCV
conditions by pan-tilt camera

Fueldebris*

Deposit three-dimensional
shape measurement

Stabilizing
anchor
The three-dimensional shape ofdeposits was measured by ascanning ultrasonic range finder

Measured by scanning
ultrasonic range finder

Deposit thickness
measurement

Measured by highoutput ultrasonic sensor

Neutron flux
measurement

Deposit surface
measurement by detector

Small amount ofdeposit sampling
Removal of install
device and seal box

The deposit
thickness wasmeasured by thehigh output
ultrasonic sensor.

Collected by thedeposit
collection device*Deposit thickness, and existence and thickness of fuel debris are uncertain, therefore, only images are described in above figures.

14©International Research Institute for Nuclear Decommissioning

Arm Type Access Device◼ An arm type access device has been produced, which canaccess on a wide range through the penetration of the
primary containment vessel (X-6 penetration) for control
rods maintenance.
⚫ Total length of the arm: Approx. 22m⚫ An investigation device up to 10kg can be loaded.
Trolley

Telescopic arm

Boom
Tilt mechanism

Two-axis joint

Wand*

Mounted sensor at the tip of the arm*An alternative tool can be mounted.

Arm type access device©International Research Institute for Nuclear Decommissioning

Arm Type Access Device (image video)

16©International Research Institute for Nuclear Decommissioning

Contents
1. Introduction
2. R&D for Investigation inside PCVs
(1) Results of completed investigation(2) R&D for next investigation
3. R&D for Fuel Debris retrieval technologies

Fuel Debris Retrieval Technology (example)

18Collection, Transfer and Storage of Fuel Debris
Canister design⇒Response to 1F specific requirements⚫ High fuel exposure and enrichment → high reactivity⚫ MCCI → hydrogen generation caused by core concrete interaction⚫ Injecting sea water, melting cable → effects caused by salt and impurities

Transfer (Dry –side access method）
R/B
Maintenancecell
Storage cellfor fuel debris
retrieval

Carry-outport(additional)

Transport cell

Fuel debris transportbuilding

Handling cell for astorage canister

Storagefacility

Unit canFuel debris
retrieval

Storing incanister

CanisterTransport cart

Washing acanister
19

Transport cask

Storing canisterin a transport
cask

Trailer

Carrying outa transportcask

End of presentation

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