R&D Activities at IRID
International Research Institute for
Nuclear Decommissioning

無断複製・転載禁止 技術研究組合 国際廃炉研究開発機構©International Research Institute for Nuclear Decommissioning1Outline of IRID
1. NameInternational Research Institute for Nuclear Decommissioning (IRID)
2. Location of Main Office
5F 3Toyo Kaiji Building, 23-1 Nishi-shinbashi 2-chome, Minato-ku
Tokyo 105-0003, Japan
website: http://www.irid.or.jp/en
3. Membership (18)
Research Institutes: Japan Atomic Energy Agency (JAEA),
National Institute of Advanced Industrial Science and Technology
Manufacturers, etc.: TOSHIBA Corporation, Hitachi-GE Nuclear Energy, Ltd.,
Mitsubishi Heavy Industries, Ltd., ATOX Co., Ltd.
Electric Utilities, etc.: Hokkaido Electric Power Co., Inc., Tohoku Electric Power Co., Inc.,Tokyo Electric Power Co., Inc., Chubu Electric Power Co., Inc.,
Hokuriku Electric Power Company, Kansai Electric Power Co., Inc.,The Chugoku Electric Power Co., Inc., Shikoku Electric Power Co., Inc.,
Kyushu Electric Power Co., Inc., The Japan Atomic Power Company,
Electric Power Development Co., Ltd., Japan Nuclear Fuel Limited
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IRID’s R&D projects in FY2015
Evaluation of Long Term
Integrity of spent fuel（FY 2015-2016）

Decontamination/
Dose Reduction

Repair and Water Leakage
Stoppage of PCV

PCV/RPV
Integrity Evaluation

Water Stoppage
Technology of PCV（FY 2015）（FY 2015）

Full-Scale
Test

Remotely Operated
Decontamination
Equipment（FY 2015）（FY 2015）

Investigation/Analysis
in the Reactor
Accident
Progression
Analysis

Detection of
Fuel Debris（FY 2015）

Investigation（FY 2015）

Investigation
Inside RPV（FY 2015）

Investigation
Inside PCV（FY 2015）

Debris Retrieval

Characterization
Identifying
Properties ofFuel Debris（FY 2015-2016）

Fundamental
Retrieval Technology
for Fuel Debris &Reactor Internals

Criticality Control （FY 2015-2016）
in Fuel Debris
Retrieval（FY 2015） Upgrading of Retrieval
Method for Fuel Debris& Reactor Internals
Collecting,（FY 2015-2016）
Transferringand Storing ofFuel Debris（FY 2015-2016）

Radioactive Waste Treatment/Disposal
Solid Waste
Treatment and Disposal(FY 2015-2016)

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IRID’s R&D projects in FY2015
Evaluation of Long
Term Integrity ofspent fuel（FY 2015-2016）

Decontamination/
Dose Reduction
Remotely Operated
Decontamination
Equipment（FY 2015）

Debris Retrieval
Repair and Water Leakage
Stoppage of PCV（FY 2015）

Water Stoppage
Technology of PCV（FY 2015）

Full-Scale
Test（FY 2015）

Investigation/Analysis in the Reactor
Accident
Progression
Analysis

Detection of
Fuel Debris（FY 2015）

Investigation
Investigation
Inside PCV（FY 2015）

PCV/RPV
Integrity Evaluation

Investigation
Inside RPV（FY 2015）

Fundamental
Retrieval Technology
for Fuel Debris &Criticality Control Reactor Internals

in Fuel Debris
Retrieval（FY 2015-2016）（FY 2015） Upgrading of Retrieval

Method for Fuel Debris
Collecting,& Reactor Internals
Transferring（FY 2015-2016）
and Storing ofFuel Debris（FY 2015-2016）（FY 2015）

Radioactive Waste Treatment/Disposal

Characterization

Solid Waste
Treatment and Disposal

Identifying
Properties ofFuel Debris(FY 2015-2016)（FY 2015-2016）

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Dose Rate Goals after decontamination
 Dose rate reduction goals to be achieved using the decontamination equipment(the necessity of PCV leakage investigation and repair work, and overall dose reduction scenario)

3 mSv/h for work area

5 mSv/h for access route

Unit 1

Unit 2

Unit 3Low as a whole: about 1-10 mSv/hHigher in south area and at some points

Before Oct. 2014: 2-60 mSv/h
After Oct. 2014: about 5-10 mSv/h(Decontamination in lower/middle
parts and shielding were conducted)

Necessity of
dose
reduction*and thedose rate

Dose rate in
the reactor
building

in southeast area: 5,000 mSv/hHigh as a whole: about 20-

100mSv/h* Mapping results of the dose rates at planned operation areas(with needs of dose reduction) derived from PCV investigation and repair project
3 mSv/h to10mSv/h

20 mSv/h to 50mSv/h

10 mSv/h to 20mSv/hMore than 50mSv/h

Out of study due to the lack of data

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Results and Future Plan of Decontamination Equipment Development
High places

Upper floors
・FY2013: design
・FY2014-2015：production, verification test, applicability study of actual device
Compressor Unit
100 m

40 m

・FY2013：design, production
・FY2014-2015：improvement, verification test, applicability
study of actual device

Decontamination Unit
20 m

Work Unit

Dry ice blast

High pressure water jet

Suction/Blast

Underground floor
・FY2014：Study of technicalchallenges, development
planning

Low places <Development completed>
・FY2011-2012：design, production, test in 2F
・FY2013：improvement, verification test (factory, 1F)

Suction/Blast
High pressure
water jet ドライアイスブラスト除染装置
Dry ice blast
吸引･ブラスト除染装置
高圧水ジェット除染装置
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IRID’s R&D projects in FY2015
Repair and Water
Leakage Stoppage of PCV

Evaluation of Long
Term Integrity ofspent fuel（FY 2015-2016）

Decontamination/
Dose Reduction
Remotely Operated
Decontamination
Equipment

Water Stoppage
Technology of PCV（FY 2015）（FY 2015）

PCV/RPV
Integrity Evaluation（FY 2015）

Full-Scale
Test（FY 2015）

Investigation/Analysis
in the Reactor
Accident
Progression
Analysis

Detection of
Fuel Debris（FY 2015）

Investigation
Investigation
Inside PCV（FY 2015）

Investigation
Inside RPV（FY 2015）

Debris Retrieval

Fundamental
Retrieval Technology
for Fuel Debris &Criticality Control Reactor Internals

in Fuel Debris
Retrieval（FY 2015-2016）（FY 2015） Upgrading of Retrieval

Method for Fuel Debris
Collecting,& Reactor Internals
Transferring（FY 2015-2016）
and Storing ofFuel Debris（FY 2015-2016）（FY 2015）

Radioactive Waste Treatment/Disposal

Characterization

Solid Waste
Treatment and Disposal

Identifying
Properties ofFuel Debris(FY 2015-2016)（FY 2015-2016）

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Target Areas for Water Leakage Stoppage at PCV
PCV Penetration (Small rooms)

PCV Penetration(Open spaces)

Cement Depositing

D/W Shell (repair)
Cement deposition

Non Cement (temporal)
Cement (Long term)

Protective cover
Cement wall

Vent Piping, Down Comer

Non-cement
material
injection

Bellows

Cement Filling

PCV
Vacuum break line

S/C Support, Torus Room
Penetrations
Cement Filling

ベント管
Vent
tube

Torus room

HeaderDown comer
T Quencher

Torus room
S/C

A half-scale test

PCV Connecting Piping
in torus room

Torus room wall
Penetrations

Column support
Seismic support

Cement Depositing
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IRID’s R&D projects in FY2015
Evaluation of Long
Term Integrity ofspent fuel（FY 2015-2016）

Repair and Water Leakage
Stoppage of PCV
Water Stoppage
Technology of PCV（FY 2015）

Decontamination/
Dose Reduction

Full-Scale
Test（FY 2015）

Remotely Operated
Decontamination
Equipment（FY 2015）

Debris Retrieval
PCV/RPV
Integrity Evaluation（FY 2015）

Fundamental
Retrieval Technology
for Fuel Debris &Criticality Control Reactor Internals

in Fuel Debris
Retrieval（FY 2015-2016）（FY 2015） Upgrading of Retrieval

Investigation/Analysis
in the Reactor

Detection of
Fuel Debris（FY 2015）

Investigation
Investigation
Inside PCV（FY 2015）

Accident
Progression
Analysis（FY 2015）

Investigation
Inside RPV（FY 2015）

Characterization
Identifying
Properties ofFuel Debris

Method for Fuel Debris
Collecting,& Reactor Internals
Transferring（FY 2015-2016）
and Storing ofFuel Debris（FY 2015-2016）

Radioactive Waste Treatment/Disposal
Solid Waste
Treatment and Disposal(FY 2015-2016)（FY 2015-2016）

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Assessing Conditions inside Reactor by
Muon Observation Technology
Transmission Method
Muon

Scattering Method
Muon

Muon
Detector
Object to bemeasuredTransmission ratio is measured

Muon Detector
Incidence angle
Emitting angle

Object to bemeasured：Detection element Scattering angle is measured

Can detect existence/non-existence of an object on
Muon flying direction（two-dimensions）

Can detect existence/non-existence of an object
at Muon scattering area（three-dimensions）

Can image fuel debris at a spatial resolution of

Can Image fuel debris at a spatial resolution of

about 1 m

about 30 cm

Detector: One small-size detector(easy installation and quick application)

Detector: One pair of large-size detectors(needs wider space and longer time to install)
Can distinguish heavy element such as Uranium

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Measurement by Transmission Method

Muon Detectors were installed at the north andnorth-west corners of Unit 1 reactor
タービン建屋building (lateDetector
N January, 2015)
 Measured from February through May

Ground Level Detectors were shielded by 10 cm thickiron plates
Detectors
設置予定位置
Reactor Building
原子炉建屋
(R/B)

N

Detectors

3 layered XY detector unit
（１m × 1 m × 1 cm）

Iron Plate shield

Network switch
UPS

R/B Cover
カバー建屋

Detector
Y-direction

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Detector
X-direction

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Estimation of Fuel Debris Location Based on Comparison between
Design Image and Measurement

Boundary of PCVBoundary of RPVBoundary of core

 Measured data, though it does not clearly indicate,shows that equipment, etc. are detected at
locations where they are supposed to exist basedon the design documents

 The boundaries of the PCV and the RPV in theimage acquired from measurement matches thosein the image drawn from design data.
 High density material (fuel debris) is not detected
at the area where fuel assemblies are originallyinstalled.

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Measurement by Scattering Method
Detectors will be installed in front of the R/B and 2nd Floor in
T/B (Operation Floor) at Unit 2
Background radiation should be eliminated by shielding andalgorism
The detector in front of the R/B should be shielded by 8 cm
thick iron plates
The detector on the second floor of the T/B will not beshielded because of low background radiation

Detector 2
Detector 1

Detector X direction
1unit

Block

Data Aggregation PC

Muon

Detector Y direction

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IRID’s R&D projects in FY2015
Repair and Water Leakage
Stoppage of PCV

Evaluation of Long
Term Integrity ofspent fuel（FY 2015-2016）

Decontamination/
Dose Reduction

Water Stoppage
Technology of PCV（FY 2015）

Full-Scale
Test（FY 2015）

Remotely Operated
Decontamination
Equipment（FY 2015）

Debris Retrieval
PCV/RPV
Integrity Evaluation（FY 2015）

Fundamental
Retrieval Technology
for Fuel Debris &Criticality Control Reactor Internals

in Fuel Debris
Retrieval（FY 2015-2016）（FY 2015） Upgrading of Retrieval

Investigation/Analysis
in the Reactor
Detection of
Fuel Debris（FY 2015）

Investigation
Investigation
Inside PCV（FY 2015）

Investigation
Inside RPV（FY 2015）

Accident
Progression
Analysis（FY 2015）

Characterization
Identifying
Properties ofFuel Debris

Method for Fuel Debris
Collecting,& Reactor Internals
Transferring（FY 2015-2016）
and Storing ofFuel Debris（FY 2015-2016）

Radioactive Waste Treatment/Disposal
Solid Waste
Treatment and Disposal(FY 2015-2016)（FY 2015-2016）

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Investigation inside the PCV (Unit 1)[Investigated area] 1stt floor grating outside the pedestal[Steps for investigation and device development](1) Investigation from X-100 penetration (FY 2015)
1. Acquire information about the grating area on the 1st floor (access point to the basement, etc.): B1(finished)
2. Acquire images showing the outside of the pedestal on the basement floor (esp. access entrance andnearby vent tube) following the results of investigation at the torus room using a small boat inNovember 2013: B2 (planning)(2) Investigation from X-6 penetration (FY 2016-2017) (after decontamination around the X-6 penetration)
1. Acquire further information about outside the pedestal on the basement floor by using fuel debris
shape measurement apparatus: B3
B1. Investigation outside the pedestal on 1st floor
grating (completed in April 2015) : from X-100B
penetration

B2. Investigation outside the pedestal on
the basement floor (planned to be done in
FY 2015) : from X-100B penetration
X-100B penetration
Access point tothe basement

X-6 penetration
CRD rail

Necessity of further investigation
will be decided according to theresults of B2

B3. Investigation outside the pedestal on
the basement and access entrance(FY 2016-2017) : from X-6 penetration

Investigation inside the pedestal is planned
to be conducted after investigation of Unit
Access entrance
No.2 finishes.
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B1 Investigation Completed in April, 2015(1)Overview of equipment- Shape-changing crawler equipment- Inserted from the narrow access entrance (X-100B penetration: φ100 mm)- Travel on the grating stably.
(2) Image of investigation routes
CRD railTraveling through penetration on PCV
Traveling direction

HVH

MS lineBoard camera*Use whentraveling
throughpiping.

B17,
B16,

Opening

B18,
B15,

C11,

C10,

B14,
B13,

C9,

B12,

C8,

B9,
C5,
C4,
C3,

Access route（4/15, 16）transformation

Traveling on grating

PLR pump
C6,※2

Crawler

B11,

C7,

HVH

Composite cable

PLR piping
B3, B4,C2,
B1,C1,C0, B0,

B8,

B5,
B6,

B2,

X-100B

B10,

B7,Opening
to B1F

Thermometer*Installedinside cover
Dosimeter*Installedinside cover

Camera forinvestigation

Features of equipment

Access route（4/10, 18）

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Results of B1 Investigation
Investigatedarea

Results

Access point
to thebasement

・For the next investigation (outside the pedestal on
the basement), it is confirmed that there is an accesspoint to the basement and no obstacles around it<Access point to the basement>

・Could not reach to the CRD rail・Could not recognize the CRD rail by evaluation of

CRD railimage-processed pictures, which were taken fromthe farthest reaching point by the investigation camera・No major damage was found inside the PCV
equipment (HVH, PLR Line, pedestal wall, etc.)
・At every investigating point, temperature and dose
rate were recorded.

En route ofinvestigation<CRD Rail><PLR pump>Support(Image at mock-up facility)
Conduit
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Investigation inside the PCV (Unit 2)[Investigated area] - On the platform inside the pedestal (Upper surface of
platform and CRD housing)- Basement floor(1) Investigation from X-6 penetration (Φ115 mm) (FY2015): A2(2) Investigation from X-6 (Enlarge hole) (FY2016- 2017): A3 and A4・Insert debris visualization system, investigate inside the pedestal.
A1. Investigation on
CRD rail(Conducted inAug.2013)

A2. Investigation on
platform inside pedestal

A3. Investigation of CRD Hsg
and on platform (detail)
ＲＰＶ
ＣＲＤ
Pedestal
OpeningX-6
penetration
Step to use X-6 penetration
・Remove shield in front of penetration
・Pierce a hole to penetration hatch・Remove inclusions inside penetration

A4. Investigation on
basement insidepedestal

Platform
CRD rail
ＰＣＶ

Traveling on
grating of 1st Fl.

Based on the results of internal investigation from A2 to A4, investigation outside pedestal may be conducted.
©International Research Institute for Nuclear Decommissioning

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IRID’s R&D projects in FY2015
Debris Retrieval

Evaluation of Long
Term Integrity ofspent fuel（FY 2015-2016）

Repair and Water Leakage
Stoppage of PCV

Decontamination/
Dose Reduction
Remotely Operated
Decontamination
Equipment

Water Stoppage
Technology of PCV（FY 2015）

Full-Scale
Test（FY 2015）（FY 2015）

Investigation/Analysis
in the Reactor
Accident
Progression
Analysis

Detection of
Fuel Debris（FY 2015）

Investigation
Investigation
Inside PCV（FY 2015）

Investigation
Inside RPV（FY 2015）

Fundamental
PCV/RPV
Retrieval Technology
Integrity Evaluation
for Fuel Debris &（FY 2015）
Reactor Internals
Criticality Control
in Fuel Debris
Retrieval（FY 2015）

Collecting,Transferringand Storing ofFuel Debris（FY 2015-2016）（FY 2015-2016）

Upgrading ofRetrieval Method
for Fuel Debris& Reactor Internals（FY 2015-2016）（FY 2015）

Radioactive Waste Treatment/Disposal

Characterization

Solid Waste
Treatment and Disposal

Identifying
Properties ofFuel Debris(FY 2015-2016)（FY 2015-2016）

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Study of fuel debris retrieval method
We will study multiple method for fuel debris retrieval to meet different condition of damaged PCV
and scattering fuel debris at each unit
Submersion method

Dry method (partial submersion, in-air work)

Most favorable approach forminimizing the radioactive
exposure of workers

Development of technology which prevents scattering radioactive materials
from PCV is needed to remove PCV contents in-air work

Top access

Side access
When fuel debris spreads overpedestal outskirts, the side
entry method is to be selected

Shield plug
Wire

Work
platform
Hydraulicmanipulator

PCV head
RPV head
Steam dryer
Steamseparator

Sealing a PCV head (1:4
scale) with Radioactive
material diffusion
preventing film

Hydraulicmanipulator

Access rail
Hydraulicmanipulator

Fuel debris

20©International Research Institute for Nuclear Decommissioning

IRID’s R&D projects in FY2015
Debris Retrieval

Evaluation of Long
Term Integrity ofspent fuel（FY 2015-2016）

Repair and Water Leakage
Stoppage of PCV

Decontamination/
Dose Reduction
Remotely Operated
Decontamination
Equipment

Water Stoppage
Technology of PCV（FY 2015）

Full-Scale
Test（FY 2015）（FY 2015）

Investigation/Analysis
in the Reactor
Accident
Progression
Analysis

Detection of
Fuel Debris（FY 2015）

Investigation
Investigation
Inside PCV（FY 2015）

Investigation
Inside RPV（FY 2015）

PCV/RPV
Integrity Evaluation（FY 2015）

Fundamental
Retrieval Technology
for Fuel Debris &Criticality Control Reactor Internals

in Fuel Debris
Retrieval（FY 2015-2016）（FY 2015） Upgrading of Retrieval

Method for Fuel Debris
Collecting,& Reactor Internals
Transferring（FY 2015-2016）
and Storing ofFuel Debris（FY 2015-2016）

Radioactive Waste Treatment/Disposal（FY 2015）

Characterization
Identifying
Properties ofFuel Debris

Solid Waste
Treatment and Disposal(FY 2015-2016)（FY 2015-2016）

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Characteristics of Nuclear Waste
Generated from Fukushima Daiichi NPS Accident
Type of Waste

Characteristics

Rubble/Felled and removed trees/soil,etc.

・Large quantity and widely distributed
・Poor experience with the treatment and disposalof felled and removed trees and soil・Surface contamination by scattering/diffusion ismain contamination and some contamination ispenetrating contamination caused by accumulated
water

Secondary waste by water treatment

・Poor experiences of treatment and disposal
・Difficult to collect the waste
・Partial estimation of quantity and kind of nuclide
may be possible based on the characteristics ofwater treatment equipment

Fuel debris/Demolishing waste

・Large amount and high dose rate
・Difficult to sample actual waste due to low
accessibility at present

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22Comparison between Wastes from Accident and Operation
Waste fromoperation

Waste from
accident

Generation of waste [quantity, type, period]◎△

Handling (collecting/classifying) [difficulty]◎△

Characterization [sufficiency of information, difficulty ofsampling, representativeness of sample]○△

Technologies for processing and packaging waste○？～△

Burial and disposal methods and safety assessment△～○？

Regulations, technical standards, guidelines, siting△～○？

Item of uncertainty◎： Fully understood or good prospect, ○： Fair prospect, △：Limited ,？： Cannot be discussed

 Waste generated from operation has its own problem but is fairly under control.
・Information on basic properties of waste, including quantity at present, future change, activity and chemical substances contained in individual waste is identified.
・Both unprocessed and processed wastes are appropriately stored and managed in accordance with the current regulations.
・Regulations and standards, as well as disposal method and safety assessment method, have been in place.

 Many uncertainties poses important technical problems to disposal of the accident-generated waste at
the Fukushima Daiichi. Solving these uncertainties and bringing the waste under control are the major
goals of countermeasures and technology development.
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～Toward Fuel Debris Retrieval～ Fuel debris retrieval at the Fukushima Daiichi Nuclear Power Station is
expected to be more difficult compared to that of the accident at theThree Mile Island 2 (TMI-2). It is necessary to put domestic andinternational wisdom together to develop the whole strategy, method
and equipment for fuel debris retrieval.
 In order to complete the fuel debris retrieval, it is necessary to clarify
the purpose and goal of relating each project, and then, to develop
technologies flexibly by planning with an aim to achieve not partial
but overall optimization.
 In making strategy, it is important to consider end-state (what you
wish to achieve at the end), study various feasible options and always
prepare alternative options.

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24Thank you for you attention

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