Subsidy Project of Decommissioning and Contaminated Water
Management in FY 2017 Supplementary Budget

Development of Technology for Construction of
Water Circulation System in PrimaryContainment Vessel
Final Research Report for FY 2019
August 2020
International Research Institute for Nuclear Decommissioning(IRID)All rights reserved.
©International Research Institute for Nuclear Decommissioning (IRID)

No.1

Contents
1. Research background and purpose
2. Project goals
3. Implementation items, their correlations, and relations
with other research
4. Implementation schedule
5. Project organization chart
6. Implementation details
7. Overall summary©International Research Institute for Nuclear Decommissioning

No.2

Major technical terms and abbreviations
Technical terms andabbreviations
Fuel debris

1F
RPV
PCV
D/W
S/C

R/B

Descriptions
Melted fuel and other solidifies that are produced under high temperatures through melting with control
rods and structures inside the primary containment vessel and reactor pressure vessel, after which
they cooled and re-solidified.
Fukushima Daiichi Nuclear Power Station
Reactor Pressure Vessel
Primary Containment Vessel
Dry Well: among PCV, a vessel that is flask-shaped and designed to contain the RPVSuppression Chamber: doughnut-shaped container installed in the basement floor of the reactor
building
Reactor Building

Penetration

Various penetrations (cavities) are designed in PCV (ex. The penetration No.6 is referred to as X-6
penetration.)

Torus room

A room containing the torus-shaped (doughnut-shaped) S/C located in the basement of the reactor
building.

JAEA Naraha

The Naraha Center for Remote Control Technology Development, Japan Atomic Energy Agency(JAEA) is a demonstration facility established for technological development required fordecommissioning of 1F.

Liquid / gas phases
systemThe system designed to confine contaminated water and air and prevent them from leaking.

Boundary
Mock-up test
MT/PT/UT/RT/VT
WJ
Extension pipe

In this project, the boundary indicates the range of the boundary to confine contaminated water andair.
A test conducted by using a full-sized test facility or equipment that is a reproduction of theapplication target.
Non-destructive test methods. From left, MT: magnetic particle testing, PT: penetrant testing, UT:
ultrasonic testing, RT: radiographic testing, VT: visual testing
Water jet: cutting with high-pressurized water squirted out of small-diameter nuzzle
A guide pipe to access inside D/W and S/C from the 1st floor of R/B©International Research Institute for Nuclear Decommissioning

No.3

List of related projects
Abbreviations

Project name

Advancement of Retrieval Method andAdvancement of Retrieval Method and System of Fuel Debris and Internal Structures
System Project
Upgrading of Fundamental Technology
Upgrading of Fundamental Technology for Retrieval of Fuel Debris and Internal Structures
Project
PCV Investigation Project

Development of Technology for Identifying Leakage Points in PCV

PCV Repair Technology Project

Development of Repair Technology for Leakage Points in PCV

Project for Detailed Investigation
technology inside PCVDevelopment of Technology for Detailed Investigation inside PCV

Project for Investigation inside PCVDevelopment of Technology for Investigation inside PCV

Project for Investigation inside RPVDevelopment of Technology for Investigation inside RPV

Project for Identification of Conditions
inside Reactor

Upgrading of Comprehensive Identification of Conditions inside Reactor

Criticality Control Project

Development of Technology for Criticality Control of Fuel Debris

Water Circulation Project

Development of Technology for Construction of Water Circulation System in PCV

Water Circulation Full-scale Test
Project

Development of Technology for Construction of Water Circulation System in PCV (fullscale test)

Corrosion Control Technology for
RPV/PCV

Development of Corrosion Control Technology for RPV and PCV

Project for Further Increasing Retrieval Development of Technology for Further Increasing the Scale of Retrieval of Fuel Debris
Scale
and Internal Structures©International Research Institute for Nuclear Decommissioning1. Research background and purpose

No.4

Background and purpose of this project
In order to retrieve fuel debris for the decommissioning of 1F, environmental improvement is important to
reduce risks caused by retrieval work and to ensure the safety. After the liquid phase and gas phasesystems for environmental improvement was developed under the Advancement of Retrieval Method andSystem Project, the plant operator is currently proceeding with engineering for the system development.
This project aims to develop technology which can be applicable to the site, for accessing and connecting
inside PCV to intake water within the water circulation system.

Project overviews
As part of environmental improvement to ensure the safety during fuel debris retrieval work, a safe water
control in PCV is significant. To implement the safe water control system, it is necessary to develop a small
circulation loop of the reactor water injection line (PCV circulation cooling) for reducing the circulation line
area of contaminated water. Establishment of the water intake structure that can directly take water from
PCV is necessary to establish the small circulation loop. Therefore, confinement functions of the gas/liquid
phases and long-term integrity are required for the water intake structure. Additionally, installation andoperation of the system will be required to use remote operated equipment in a high radiation environment
site. A high-level technology for design, establishment and maintenance that is required is developed in thisproject.
Accessing and connecting technology which has high on-site feasibility is developed for the water
circulation system in cooperation with relevant project, Advancement of Retrieval Method and System
Project, and verified in actual scale accordingly.
As for D/W water intake establishment technology that is part of the water circulation system, element
technology is developed and verified. As for S/C water intake establishment technology, element technology
is developed and verified up to actual scale.
This project report describes achievements of the Water Circulation Project for 2 years during fiscal
years 2018 and 2019.
©International Research Institute for Nuclear Decommissioning

No.5

1. Research background and purpose
Advancement of Retrieval
Method and System Project・Outline study of system
・Element technology(particle removal
technology) (soluble nuclide
removal apparatus)(a) Circulation coolingsystem(a) 循環冷却設備

To
contaminated
汚染水処
water
treatment
system
理設備へ
非常用
Emergency
bufferバッファタンク
tank(b) Contaminated water(b)
汚染水処理設備
treatment
systemCriticality control
Project
・Boric acid system
From
CST
CSTより

ホウ酸水タンク
Boric
acid
（非常用）
solutiontank(emergency)

Large circulation loop
Iron
鉄共沈
coprecipitation
処理設備
treatment
apparatus

Large circulation loop
Boric ホウ酸水タンク
acid solution tank

ToCSTへCST

From
torus room
トーラスよりSmall circulation
loop
溶解性核種
Solublenuclidesremovalapparatus
除去設備

非溶解性α核種
In-soluble
α nuclides
removal apparatus
除去設備

Purification 浄化装置
apparatus
Secondaryboundary
2次バウンダリ水
water treatment
system
処理系

RO
system
RO装置(salt removal)（塩分除去）

冷却設備
CoolingsystemIn-soluble α
非溶解性α核種
nuclides removal
除去設備
system

溶解性核種
Soluble nuclides
removal system
除去設備

Adsorption
吸着設備
apparatus(Cs/Sr
removal)(Cs/Sr除去)

Carbonate
炭酸塩沈殿
coprecipitation
処理設備
treatment
apparatus

Adsorption
吸着設備
apparatus (multi(多核種除去)
nuclideremoval)

To treated
処理済水
water貯槽へ
tank

浄化装置
Purification
apparatus:New system：新設設備

１次バウンダリ水
Primaryboundary
water treatment
処理系 system:Existing system：既設設備

A high radiation environment and boundary maintaining are necessary to establish water intake points in D/W and S/C,
which require high-level technology. Therefore, technology for establishment of water intake points in D/W and S/C isdeveloped by this project.
Remarks: See Reference 2 for necessity of establishing PCV circulation
cooling(small circulation loop) system and water intake
structure as well as developing access technology.

Fig. Water circulation system during fuel debris retrieval (conceptual drawing)©International Research Institute for Nuclear Decommissioning⚫ Development points: Technology for water intake part establishment (1/3) No.6
To respond to requirements by the Advancement of Retrieval Method and System Project, technology for establishmentof access and water intake parts to take water into PCV is developed, which is quite difficult.

Advancement of Retrieval Method and System
Project

Water Circulation Project,
Water Circulation Full-scale Test Project

Establishment of water circulation system
Establishment of PCV water intake opening is required,
which will be a starting point of circulation.

【Required functions】

Development of technology for accessing andconnecting PCVWork in the area adjacent to【Development points】 PCV with high radiation dose

Prevention of leakage and spread of radioactive
materials

Connection structure with earthquake-resistance strengthand sealing property

Reduction of radiation exposure for workers

Remote operation work

Maintaining long-term functions during fuel debris
retrieval

Boundary maintaining during work

Maintenance of system equipment

Boundary maintaining during system equipment
maintenanceFunction maintaining for external events(earthquake)

Maintenance for connection parts

Water intake from low water levels of D/W and S/C

Access to low water levels of D/W and S/C

The required specifications and functions for access and water intake part of water circulations were examined in this project, and then development
effort will be made to solve technological issues. Descriptions are given in the figures on the following slides.
©International Research Institute for Nuclear Decommissioning⚫ Development points: Technology for water intake part establishment (2/3)

No.7① Required specifications and functions of technological development for establishment ofwater circulation system in Ｄ/Ｗ：Required specifications and functions：Issues to be discussed
Boundary maintaining method
during work and maintenance

Environment conditions in PCV［During work］
In waterPositive air pressure ５KPa
Negative air pressure -200Pa［During fuel debris retrieval］
Negative air pressure -200Pa

Selecting penetration parts
Required strength, sealing property/ connection method,maintenance method

Inspection requirement for water
circulation system
Water intake hose installation apparatus

Boring method for X-2 outside door
Dose rate in atmosphere

Required installation
Weight of water intake hose installation apparatus
Seismic resistance requirement
Connection conditions

Extension pipe support method
Boring method for X-2 inside door

Grating opening method

Extension pipe
Primary boundary

Required opening
diameter

Water intake line installation method
avoiding interference objects in Ｄ/W
Pump transfer and suspension
Hose adjustment
Pump/hose replacement andconnection
Conditions of deposits

Number of systems
Pipe (hose) diameter
Pipe (hose) material
Pipe (hose)weight
Pipe (hose)support
methodPump size, weight
Measurement items,
methods
Maintenance frequency
Confirmation of
sympathetic vibrations

A penetration section for D/W water intake part is selected according to required layout of the water circulation system.
This figure is an example of X-2 water intake.
©International Research Institute for Nuclear Decommissioning

No.8② Required specifications and functions of technological development for establishment ofwater circulation system in S/C Pump replacement
Dose rate in
Required installation⚫ Development points: Technology for water intake part establishment (3/3)
apparatus
ポンプ交換装置：Required specifications and：要求仕様,要求機能
functions：検討課題：Issues to be discussed

配置要求

雰囲気線量
atmosphere

Weight of pump
ポンプ交換装置重量
replacement
apparatus
Seismic
resistance
Seismic
requirements
requirement
取合い条件
Connection conditions

Boundary maintaining
施工時,メンテナンス時のmethodduring work andmaintenanceバウンダリ維持方法

Support method
Confirmation of sympathetic vibrations

Remote operation
遠隔構築技術
technology
遠隔メンテナンス技術
Remotemaintenancetechnology
遠隔検査技術
Remote inspection
technology

Inspection requirement forwater circulation system

1st floor at R/B

12750

Torus room is Inaccessible
for workers due to highradiation dose⇒Work on 1st floor of R/B

3850

Required opening diameter
Required strength, sealing capability/
Connection method / opening method
Maintenance method
Ensuring seismic resistancePrimary boundary
Environment conditions in PCV［During work］
In waterPositive air pressure ５KPa
Negative air pressure -200Pa［During fuel debris retrieval］
Negative air pressure -200Pa

Number of systems
Pipe (hose) diameter
Pipe (hose) material
Pipe (hose)weight
Pipe (hose)support method
Pump size, weight
Measurement items, methods
Maintenance frequency

Water level of torus room
Ground water level

Floor surface of torus room

Conditions of deposits

Water intake at low position of S/CArrangement of installation route
Water intake line setting,
maintenance©International Research Institute for Nuclear DecommissioningNo.9

2. Project goals➢ Level of achievement (1/2)

According to the definitions of the technology readiness levels (TRL) as below, expectationlevels at times of goal achievement in full-scale tests are established and R&D is conducted.
LevelsDefinitions applicable to this project

Phases7

Practical application completed

Actual operation

6

Technology demonstration in operational environments

Field
demonstration

5

Prototype equipment is developed and demonstrated in a simulated
environment such as manufacturing plant.

Demonstrationin operation

4

Prototype-level function test conducted as part of process for technology
development and engineering

Research forpractical
application

3

Technology and engineering are developed by applying and combining withexisting knowledge. Or, technology and engineering are developed basedon basic data, in which there is little existing knowledge.

Application
research

2

Technology and engineering for specific fields, in which existing knowledge
can rarely be utilized, are developed, and required specifications are set.

Application
research

1

Basic details of targets for technological development and engineering areclarified.

Basic research©International Research Institute for Nuclear DecommissioningNo.102. Project goals➢ Level of achievement (2/2)⚫ Development of technology for the establishment of water circulation systems inside PCV
Items

Criteria for determining goal achievement

Technology for accessing andconnecting inside D/W

Element tests pertaining to the technology for remotely operating theconnection parts should be completed at the factory and the acceptancecriteria of the element tests should be met. Or else, the issues to beresolved and the resolution policy should be clearly specified.
(Target TRL at completion: 4)
Element tests pertaining to the technology for remotely operating theconnection parts should be completed at the factory and the acceptancecriteria of the element tests should be met. Or else, the issues to beresolved and the resolution policy should be clearly specified.
(Target TRL at completion: 4)

Technology for accessing andconnecting inside S/CElement tests pertaining to the technology for remotely inspecting accessroutes while in service at the time of establishment, should be completed at
the factory and the acceptance criteria of the element tests should be met.
Or else, the issues to be resolved and the resolution policy should beclearly specified.
(Target TRL at completion: 4)
Element tests pertaining to the technology for remotely carrying out
maintenance of the connection parts while in service at the time ofestablishment, should be completed at the factory and the acceptancecriteria of the element tests should be met. Or else, the issues to beresolved and the resolution policy should be clearly specified.
(Target TRL at completion: 4)©International Research Institute for Nuclear Decommissioning3. Implementation items, their correlations, and relations with other research

No.11

3.1 Review of the overall project and hold points (HP)
Water Circulation Project(1) Organization of technical specifications for the advancement of the water circulation system in PCV, review of work plans, and drawing up of development plans② Review of the system and technology for water circulation using the S/C① Review of the system and technology for water circulation inside D/W
Organization of technicalspecifications considering the site
environment

Work of constructing the access
route
・Review of the maintenance plan

Environmental Conditions
Layout requirements
Seismic requirements
Number of systems
Pipe (hose) specifications(diameter)
Etc.

Organization of technicalspecifications considering the site
environment

Work of constructing the access
route
・Review of the maintenance plan

Development results of other projects
and past technologies

Identifying development
challenges and drawing up of
development plans

Development results of other projects
and past technologies

Identifying development challenges
and drawing up of development
plans

HP1

Environmental Conditions
Layout requirements
Seismic requirements
Number of systems
Pipe (hose) specifications(diameter)
Etc.

HP3

(2) Development and verification of element technologies foraccessing and connecting inside PCVDevelopment and verification ofelement technologies

Development and verification ofelement technologies

HP2

Drawing up of full-scale test plans

HP4

HP4
Water Circulation Full-scale
Test Project(1) Full-scale verification of technology for accessing and connecting inside PCV
Full-scale verification
Full-scale verification[HP1] ・Validity of the required specifications and functions
・Necessity of development
・Validity of the development plans[HP2] ・Level of achievement with respect to the required specifications and functions,determined during the element tests[HP3] ・Validity of the required specifications and functions
・Necessity of development
・Validity of the development plan[HP4] ・Level of achievement with respect to the requirement specifications and functions,determined during the element tests
・ Validity of full-scale test plans

Integrity confirmation after welding
the connection parts

LegendValidation of the water circulation
system boundary: Applicable to the Water Circulation Technology Development
Project, Water Circulation Full-scale Test Project: Not applicable to the Water Circulation Technology Development
Project, Water Circulation Full-scale Test Project©International Research Institute for Nuclear Decommissioning3. Implementation items, their correlations, and relations with other research
3.2 Relations with other research
Advancement of Retrieval Method andSystem of Fuel Debris and Internal
Structures (completed)

No.12

Development of Technology for Further
Increasing the Scale of Retrieval of Fuel
Debris and Internal Structures*

Results of outline study of water
systemDevelopment status of prevention
method for spreading fuel debris

Functional requirements of water
systemStudy results of water intake point
establishment for D/W and S/CStudy results of water intake point
establishment for D/W and S/C

Development of Technology for Constructionof Water Circulation System in PCVProcedures of full-scale test

Development of Repair Technology
for Leakage Points in PCV(completed)

Results of full-scale test
Development of Technology for
Construction of Water Circulation
System in PCV (full-scale test)

Development results of PCV repair(extension pipes, etc.)

Development of Technology for Detailed
Investigation inside PCV
Upgrading for Identifying Comprehensive
Conditions inside the Reactor (completed)

Conditions of RPV/PCV interior
including fuel debris fallen positions andranges, and corrosion status*This project was named as Development of Technology for Retrieval of Fuel
Debris and Internal Structures, when the project started. According to thedevelopment plan of decommissioning research in FY 2020 disclosed at the75th Secretariat Team Meeting for Countermeasures for Decommissioning
and Contaminated Water Treatment, the project name was changed to
Development of Technology for Further Increasing the Scale of Retrieval of
Fuel Debris and Internal Structures.

Preliminary engineering
Legends：R&D project, engineering：Project organization：Information correspondence：In-put：Out-put

The site conditions of each unit
(deposits, water levels, radiationdose of 1st floor of R/B andstructure information)
Study results of water intake
candidate points for D/W and S/C©International Research Institute for Nuclear DecommissioningNo.13

4. Implementation schedule (Water Circulation Project)① Schedule for constructing the D/W water intake part
Up to
2017

: Planning (initial),

2018 / First
half: Planning (after revision),2018 / Second
half2019 / First
half:Results (as of end of March 2020)2019 / Second
half2020 onwards(“PCV Repair Technology Project”, “Advancement of Retrieval Method and System Project”, “Projectfor Detailed Investigation Technology Project for Detailed Investigation inside PCV”)(1) Organization of technical specifications for the advancement of the water circulation system in PCV, review of work plans, anddrawing up of development plans[HP1]・Validity of the required specifications and functions
・Necessity of development
・Validity of the development plans[HP2]・Level of achievement with respect to the required
specifications and functions, determined during theelement tests① Review of the system and technology forwater circulation inside D/Wi) Organization of technical specifications
considering the site environmentii) Study of the access route establishment
work and maintenance plan

▽HP1iii) Identification of development challenges
and drawing up of development plans▼HP1(2) Development and verification of element technologies for accessing and connecting inside PCV▼HP2① Development and verification of element
technologies needed for accessing andconnecting inside D/W

Major milestones

Development to becontinued as required▲
Interim
Report▲Interim
Report▲Interim
Report▲Final report©International Research Institute for Nuclear DecommissioningNo.14

4. Implementation schedule (Water Circulation Project)② Schedule for constructing the S/C water intake part
Up to
2017

: Planning (initial),: Planning (after revision)

2018 / Second
half2018 / First half

: Results (as of end of March 2020)2019 / Second
half2019 / First half2020 onwards(“PCV Repair Technology Project”, “Advancement of Retrieval Method and System Project”, “Project for Detailed Investigation Technology Project for Detailed Investigation inside PCV ”)(1) Organization of technical specifications for the advancement of the water circulation system in PCV, review of work plans, anddrawing up of development plans[HP3]・Validity of the required specifications and functions
・Necessity of development
・Validity of the development plans[HP4]・Level of achievement with respect to the required
specifications and functions, determined during theelement tests
・ Validity of full-scale test plans② Review of the system and technology forwater circulation using the S/Ci) Organization of technical specifications
considering the site environmentii) Study of the access route establishment
work and maintenance planiii) Identification of development challenges
and drawing up of development plans

Review of technical specifications due
to major structural modifications
associated with permanent installationof S/C extension pipe, establishment ofaccess route, securing time forstudying the development plans

▽HP3
HP3 ▼

(2) Development and verification of element technologies for accessing and connecting inside PCV② Development and verification of element
technologies needed for accessing andconnecting inside S/C
The initial plans assumed that element tests
would be started early on as a result of minor
alterations in the remote operation equipment for
the existing guide pipe (extension pipe) andwould be implemented at JAEA’s Naraha Center.

▽HP4
▼HP4

Element test planning(Proceed to full-scale test)

Element tests of the extension
pipe connection device

Element tests of extension
pipe maintenance(Proceed to full-scale test)

Major milestones

Development to becontinued as required

▲

▲

▲

Interim Report

Interim Report

Interim Report▲
Final report©International Research Institute for Nuclear Decommissioning5. Project organization chart (Water Circulation Project)International Research Institute for Nuclear
Decommissioning (IRID): Headquarter

No.15

Tokyo Electric Power Company Holdings, Inc.
: Research partner○ Overall project planning and coordination of overall
technology○ Coordination of technology management including
technological development○ Management of research and development

Toshiba Energy Systems & Solutions Corporation

Hitachi-GE Nuclear Energy, Ltd.

(1) Examining of technical specifications for upgrading of water
circulation systems in PCV, study of work plan and development
planning(2) Development and verification of element technology for accessing
and connecting inside PCV・Development and verification of element technology for accessing
and connecting inside S/C(1) Examining of technical specifications for upgrading of water
circulation systems in PCV, study of work plan anddevelopment planning(2) Development and verification of element technology foraccessing and connecting inside PCV・Development and verification of element technology foraccessing and connecting inside S/C

IHI Corporation○ Element test for accessing and connecting inside
S/C

Toko Corporation (Chugai Technos Corporation)○ Element test for assessing and connecting
inside D/W
Hitachi Power Solutions Co., Ltd.
○ Design support of accessing and connecting
inside PCV©International Research Institute for Nuclear Decommissioning6. Implementation details

No.16(1) Examining of technical specifications for upgrading of water circulation systems in
PCV, study of work plan and development planning① Study of the water circulation system and technology for inside D/Wi) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenance planiii) Identification of development challenges and preparation of development plan
② Study of the water circulation system and technology by using S/Ci) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenanceiii) Identification of development challenges and preparation of development plan
(2) Development and verification of element technology for accessing andconnecting inside PCV① Development and verification of element technology required for accessing
and connecting inside D/W②Development and verification of element technology required for accessing

and connecting inside S/C©International Research Institute for Nuclear Decommissioning

(1)①i)-1 Results of organizing technical specifications related toestablishment of access route for D/W water intake

No.17⚫ The technical specifications related to establishment of access route for D/W water intake in this project wereorganized as shown in the following table, based on the results of clarifying site conditions.
No.

Items

1

Access route into PCVAssuming that existing through holes will be used, new through holes shall not be made.
The access routes for large scale retrieval and existing through holes shall be used.

2

Environmental radiation rate

[R/B 1st floor] 10mSv/h

3

Water level inside D/W

Shall be lower than the 1st floor grating

4

Sediment deposits in D/W

Shall be considered. However, removal work shall be outside of the scope of technological development.
The technical configuration shall be such that the water intake point inside D/W can be changed
depending on the status of removal of sediment deposits.

5Interference objects inside D/WTechnical specifications

Remarks

Assuming that the remote
operated equipment has been
installed inside D/W andinterference objects havebeen removed.

Shall be considered as removed.

Water intake shall be at the pump pit.
[Reason]The effective and reasonable D/W water intake point shall change depending on the actual conditions(sediment deposits, interference objects, work environment outside PCV, etc.) Moreover, it is assumed
that there would be changes in stages, during the activities for fuel debris retrieval. Due to these reasons,at this point in time the position cannot be specified.
Hence in this project, specific technology shall be developed assuming that the pump pit would be thewater intake position, as it is at a distance from the access opening, and is believed to be the mostdifficult position in terms of establishment, since pipes would have to be laid inside the PCV by means of
the remote operated equipment, so that if another location is to be used as the water intake position, thistechnology can be applied there as well.

6

Water intake position inside D/W

7

Number of systems (maximum)

Normal: 2, Emergency: 2 (can be portable as well)

8

Water intake pipe (hose) diameter(maximum)[When pump is installed inside PCV] 50A[When pump is installed outside PCV] 100A

Pump external dimensions / weight[When installed inside PCV] Φ0.28m×0.75mH / weight 80kg/unit[When installed outside PCV] 1.5mL×0.6mL×0.5mH, 500kg/unit

9(submersible pump)(vacuum pump)

The pump size shall berevised as requiredconsidering workability.

©International Research Institute for Nuclear Decommissioning

(1)①i)-2 Identification of candidate access openings for D/W water intake fromamong the existing penetrations, and comparative study pertaining to feasibility

No.18⚫ From among the penetrations made on the R/B 1st floor in each unit, a comparative study was conducted targeting thepenetrations that opened up the inside of PCV.
⚫ As a result of considering the workability at the penetration site (height at which the penetration is made, its internal diameter,dose rate in the surrounding space), penetrations that would be highly effective as water intake, and that have a higher
possibility of being used as water intake for D/W in each unit are listed in the table below.
⚫ From among the various types of penetrations, X-1(1A/1B), X-2 and X-6 that were identified in common between the units
were taken up as representative penetrations, and the access routes for D/W water intake were specifically studied in (1)①ii).
Penetration types

1F-1

1F-2

1F-3

Hatch (with shield plug)

X-1

X-1A, 1B

X-1A, 1B

Hatch (double door)

X-2

X-2

X-2

X-6

X-6

X-6

X-20

X-44

X-53

X-100B

X-46.47

Pipe, back-up

X-53

X-100B X-20

Layout of candidate
penetrations for water
intake

X-1

X-44

X-53
X-6

X-1A

X-2

X-2
X-6

X-1B

X-6 X-53

X-46
X-47

X-1A

X-2
X-1B

©International Research Institute for Nuclear DecommissioningNo.19(1)① ii)-1 Study on the method of establishing access route for the D/Wwater intake (1/2)⚫ It is efficient to use existing penetrations as the access route for the D/W water intake, and hence prospective
penetrations were identified as candidates in (1)①i).
⚫ With respect to the technology for constructing the access routes using existing penetrations, since this method
has been implemented in other projects, as also related technologies are currently being studied or are
undergoing element tests, the applicability of existing technologies to the candidate penetrations was studied
and the necessity of developing the technology for constructing the access routes was put into perspective.
⚫ Examples of existing technologies (including those that are currently under development as part of various
projects) that would be useful in constructing the access route for the D/W water intake are as follows:

a.
b.
c.

[New extension pipe establishment technology] 1F-1: Technology for connecting the extension pipe for X-2
penetration “Project for Detailed Investigation Technology inside PCV”
[Shield opening technology] 1F-2/3: BSW opening and sealing technology “Upgrading of Fundamental
Technology Project”[Penetration remote connection technology] 1F -2/ 3: Technology for the connection with X-6 penetration“Project for Detailed Investigation Technology inside PCV”
Isolation
隔離弁
valve

Non-metallic

Isolation valve

非金属ベローズ
bellows

Temporary house:
Diffusion prevention

PCV side
PCV側(X-6
penetration（X-6ペネ側）
side)

Main body of the
接続管本体pipe
connectingCore drillCore drilling apparatus
Filter and dust collector
Drive
駆動機構
mechanism

Extension pipe

Figure. Technology for connecting theextension pipe for X-2 penetration

Figure. BSW opening andsealing technologyArmcleaning
アーム洗浄
and drying
・乾燥機構
mechanism

Figure. Technology for connection
with X-6 penetration©International Research Institute for Nuclear Decommissioning

(1)① ii)-1 Study on the method of establishing access route for the D/W water intake (2/2) No.20
X-1

Unit

1F-1

1F-2

1F-3

1F-2

1F-3

1F-1

1F-2

1F-3

1F-1

1F-2

1F-3

(a) X-2extensionpipeconnection

△

△

△

△

△

○

△

△

△

△

△

(b) BSW
opening

△

△

△

△

△

－

△

△

－

－

－

(c) X-6
connection

－

－

－

－

－

－

－

－

△

△

△

Applicability of existing
technologies

Candidate penetrations

X-1A

X-1B

X-2

X-6

[Legend] ○: Can be applied (without issues), △: Can be applied (with issues), ×: Cannot be applied, －: Not applicable✓ Applicability of existing access route establishment technologies:
Although there are aspects that need to be studied in detail with respect to application, it is anticipated that the existing technologies can be applied.
Cable drum

Isolation
valve (closed
or open)

Extension
pipe

Guide pipe
Installation
deviceInvestigationequipment

Seal box
Seal part(O ring, etc.)

Release of
Nitrogencontaminated gas
gas(using filter)
injection

O ringBoundary

Figure. Example of access route establishment for the equipment for detailed investigation inside PCV**: (Source) Development of Technology for Detailed Investigation inside PCV PJ Study material©International Research Institute for Nuclear Decommissioning

(1)① iii)-1 Identification and organization of challenges in developing the system andtechnology for water circulation inside D/W, and drawing up development plans

No.21⚫ Issues in developing the technology for constructing the water circulation system in D/W① Construction of access route to PCV
Outside PCV(1st floor of R/B)

Inside PCV: Issues to bestudied in thisproject

Ｘ-2 (Air lock)
D/W water
intake pipe

To the liquid
phase
system⑤ Removal of interference
objects from PCVExtension pipe

To the liquid
phase system⑥ Removal of pumpfrom pump pit
Extension pipe
D/W water intakepump④ Suspension andinstallation of pump on thebasement floor

D/W water
intake pipe
D/W water intake pump

[Examples of applicable existing technologies]② Unrolling of pipe (hose) on grating[horizontal direction]③ Unrolling of pipe (hose) [verticaldirection]

IssuesExamples of existing technologies① Construction of access route to PCVTechnology for installing extension pipes (Project for Detailed Investigation inside PCV), technology for connecting theaccess tunnel (Advancement of Retrieval Method and System Project for 1F-1 X-2)

⑤ Removal of interference objects from PCV⑥ Removal of pump from pump pit

Technology for removal of interference objects outside the pedestal (Upgrading of Fundamental Technology Project)Studies will be conducted to resolve the issues of unrolling (horizontal or vertical direction) the pipe (hose)
inside the PCV and suspension and installation of pump on the basement floor.
©International Research Institute for Nuclear DecommissioningNo.22

6. Implementation details(1) Examining of technical specifications for upgrading of water circulation
systems in PCV, study of work plan and development planning① Study of the water circulation system and technology for inside D/Wi) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenance planiii) Identification of development challenges and preparation of development plan
② Study of the water circulation system and technology by using S/Ci) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenance planiii) Identification of development challenges and preparation of development plan

(2) Development and verification of element technology for accessing andconnecting inside PCV① Development and verification of element technology required for accessing
and connecting inside D/W②Development and verification of element technology required for accessing
and connecting inside S/C©International Research Institute for Nuclear Decommissioning

(1) Organization of technical specifications for the advancement of the water circulation system in PCV

No.23[Overview of results] i) Organization of technical specifications considering the site environment◼ Safety and system functional requirements and goals of this project (planned) with respect to each defensein-depth level of the gas phase boundary during fuel debris retrieval[Purpose]
To draw up the technology development plan for theestablishment of a water intake opening in the S/C.

Protectionlevel[Issues]i) Organization of technical specifications considering
the site environmentii) Study of the access route establishment work andmaintenance planiii) Identification of development challenges anddrawing up of development plans◼ Conformance to the functional requirements of the gas
phase boundary with respect to the extension pipe for
the S/C water intake opening
Protection
level

Monitoring

Systemfunctional
requirements

-

1

2

Policy ofconformance withrequirements-

Systemfunctional
requirements

It should be possible to detect thepresence of leakage from the S/C water
intake opening when an increase inleakage is detected in the negative
pressure management system.

The presence of leakage should be
confirmed by leakage or other tests when
Policy of
an increase in openings is detectedconformance withthrough the monitoring of the exhaust
requirements
flow rate of the PCV internal pressure /negative pressure management system.

FP barrier against gas phase leakage
System functional requirements*1

Goals of this project (S/C water intake part)

1

Openings aligned with the existing damage points and othernew connection parts should satisfy the study conditions forthe system (Amount of in-leak when securing the required
differential pressure: 1000 m3/h or less).

Slight increase in the primary boundary opening
area: (1 mm2)*2 or less2

Same condition as level 1

Increase in the primary boundary opening area: (2cm2)*3 or less3

Level 3 includes a policy of confinement at the secondary
boundary and there is no direct requirement regarding the
primary boundary-*1: Incorporating the progress of the Advancement of Retrieval Method and System Project*2: Assuming that the current 1F-2 gas phase opening area (1 cm2) is an increase in the number of openings for the entire system, the S/C intake is set to 1% of
the total amount.
*3: Assuming that the rupture (2 cm2) of a small diameter pipe (15A) is an increase in the number of openings for the entire system, the S/C water intake isconsidered to be the same as the total amount.
(Presuming that a single event occurred at the water intake opening)

Prevention

Mitigation① Should have sufficient strength against the load acting on the S/C water intake opening② Should be able to control corrosion of the structural members③ Should be able to confirm the absence of abnormality by VT and absence of leakage by leakage test from the inside of the water
intake structure at the time of completion of work, and should be able to confirm the absence of abnormality by VT from the inside of
the water intake structure during the maintenance of the water circulation system.
①-1 A displacement absorption mechanism should be added between 1st floor of R/B and S/C and the extension pipe should besuspended from the 1st floor to control the excessive stress at the joints with the S/C shell.
①-2 The necessary throat thickness should be ensured in consideration of the joint efficiency of the weld.
②-1 Openings due to corrosion should be prevented by securing a corrosion allowance during work.
②-2 The progress of corrosion should be controlled by using an anti-corrosion coating.
②-3 The coating should be repaired when necessary to control corrosion in accordance with VT results during the maintenance of thewater circulation system.
③ The absence of abnormality should be confirmed by VT and absence of leakage should be confirmed by leakage test from theinside of the water intake structure at the time of completion of work, and the absence of abnormality should be confirmed by VTfrom the inside of the water intake structure during the maintenance of the water circulation system.

--

It should be possible to prevent non-ductile fracture of boundary components.

It should be possible
to stop or control
leakage.

Non-ductile fracture should be prevented by using ductile material.

Leakage should be
stopped orcontrolled byapplying repair
material to theleakage points.

(Supplement) ○ Level 3 includes a policy of confinement at the secondary boundary and there is no functional requirement for the extension pipe at the primary boundary.
○ The following response measures are assumed after restoration from an abnormality:
・Remove the water intake apparatus from the S/C water intake opening, and stop or control the leakage by closing the S/C opening.
・During the period when the leakage is stopped or controlled by closing the S/C opening, repair the leakage points or close the S/C water intake opening.

©International Research Institute for Nuclear Decommissioning

(1) Organization of technical specifications for the advancement of the water circulation system in PCV◼ Structure of the S/C water intake part
Suspend theextension pipe
from the 1st floor
Pipe changed to SUS
as a corrosion
countermeasure
Add a displacement
absorption mechanism
between 1st floor of
R/B and S/CStudy the connection
structure of theextension pipe (SUS)and S/C shell (carbon
steel) to avoid
connecting different
materials on site

◼ Development goals for the S/C water intake part
① Welding of S/C joints⚫
Weld S/C joints with joint efficiency equivalent to 0.35
Mutatis mutandis application of the specified joint efficiency of 0.35 * for core support structures*: JSME Rules on Design and Construction CSS-3150: Only visual testing
Joint efficiency of one-side fillet weld⚫
Weld quality should not vary due to the following, and a stable weld quality must be ensured:✓
Establishment of appropriate welding conditions (torch angle, torch rotation speed, etc.)✓
Establishment of welding procedures (addition of clockwise rotation of torch, etc.)✓
Gap tolerance settings✓
Automatic welding by controlling the program for appropriate trajectory and torch aiming position
according to the measured gap✓
Development of indicated value and actual value records for weld parameters② Inspection during work⚫
⚫
⚫

Structure adopted in this project(Inside)Shop welding(SUS316L)
Shop welding(SUS309L)
Shop painting
On-site painting
On-site welding*1(carbon steel)(Outside)
Extension pipe
(SUS)

Short pipe
(carbon steel)On-site application of
repair material

S/C shell (carbon steel)

No.24

VT: Use the camera to ensure that there are no harmful incidents such as cracks or undercuts,
overlaps, craters, slag inclusion, blowholes, etc. (Mutatis mutandis application of CSS-4222(2)specifications)
DT: Prescribed throat thickness and leg length are satisfied
Leakage test: Confirm the absence of leakage through the air pressure test on the extension pipe
(inside).

③ Maintenance inspection and repairs (Supposed to be conducted once in 10 years)⚫
⚫

VT: There is no abnormal onset of rusting in the extension pipe (inside and outside).
Repair coating: In accordance with the results of VT, repair the coating through remote operations.

④ Level 2 inspection and repairs<Inspection>⚫
VT: There is no abnormality in the extension pipe (inside and outside).
⚫
Leakage test (air pressurization): Temporarily close the extension pipe (inside) and make sure that
there is no leakage due to air pressurization.
⚫
Leakage verification (foaming test): Utilize the negative pressure within the PCV and make sure that
there is no leakage from the extension pipe (inner surface) by means of a foaming test.
⚫
Leakage test (tracer gas): Utilize the negative pressure within the PCV, and make sure that there is
no leakage in the S/C connection parts based on the tracer gas from the extension pipe (outersurface).
<Repair>⚫
Repair of leakage points: Remotely repair leakage points by applying a coating agent from theextension pipe (inside and outside).
(For repairs from the inside, the inside of the extension pipe needs to be airtight as the flow of air
inward to the repair point at PCV negative pressure is stopped by temporary closing the pipe.)⚫
VT: The state of the repair points can be verified.

Welding of carbon steel pipes©International Research Institute for Nuclear DecommissioningNo.25(1) Organization of technical specifications for the advancement of the water circulation system in PCV◼ Layout plan for S/C water intake part (Study results for S/C water intake part layout: Example of Unit 1)⚫Priority A

Fuel debris
retrieval facility(north west)[Study results]• In Units 1 to 3, 8 or more S/C water intake openings can be
1st floor ofplaced at 66° or more of θ in the figure.
R/B⇒
Developwelding
apparatus
with
the
said
angle
θ
set
to
⚫Priority B
Torus
66°
or
more.
(There is area interference withroom
fuel debris retrieval facility (south • The interference objects in the torus room need to be
removed remotely.
east))⇒ Conduct a conceptual study on the procedure of removal
2.8 to 25 mSv/h ⚫Priority C (high level of technical(Localized high dose)of the typical interference objects in the torus room (pipes,
requirements)
cable trays, air conditioning ducts, and handrails) using the(Construction of new access route
PCV bottom part repair apparatus (FRM).
required)• The study on the removal of interference objects from 1st*: Dose reduction measures arefloor of R/B will be considered as future engineering scope
desirable or indispensable.
as necessary, and will be out of scope of this project.
1 to 10 mSv/h
θ: Angle between the(Localized high dose)• The impact of interferences of the structures inside S/C
extension pipe axial(vent pipes, vent headers, and downcomers) and the water
direction and theFuel debris
tangent to the S/C shellintake apparatus needs to be verified, but the extent of
retrieval facility
meridional direction at
impact is expected to be small due to the flexible hose.
(south east)
the lowermost position• High dose areas are included in the selected points, and50 mSv/h or moreof the extension pipe
hence dose reduction measures are essential.

Extensionpipe(No area interference with fueldebris retrieval facility)

S/C shell

L: Horizontal distance
between the shaft ofthe extension pipe
and the center of S/C(The position where θ
is 66° or more, is at1330 mm or less inUnit 1, and 1500 mm
or less in Units 2 and3)ii) Study of the access route establishment work and maintenance plan
◼ Procedure for establishment of S/C water intake part
STEP1 Removal of interference objects fromtorus room as preliminary work
• Removal of interference objects from torus
room• Installation of base plate• Carrying in and fixing of installation cart
STEP4 Positioning of extension pipe and S/Csurface・Polishing of S/C surface
・Installation of the positioning apparatus
・Finding the amount of deviation of theextension pipe
・Positioning
・Measurement of weld gaps

STEP6 From support to pressure resistanceof extension pipe
• Supporting extension pipe
• Unfixing of bellows• Installation of isolation mechanism• Weld pressure resistance and leakage
test

STEP2 Pre-treatment of S/C surface
・Peeling off the coating
・Grinding extra banking of welds
・Surface marking

STEP3 Fabrication and inspection of extension pipe・Measurement of S/C surface
・Creation of a 3D model and creation of groove drawings
・Processing of extension pipe grooves
・Fabrication of extension pipe [welding and inspection of lower,
middle, and upper parts]

STEP5 Welding of extension pipe and S/Csurface• Welding• Weld cleaning [polishing and suction], weld
inspection [VT]• Weld treatment [grinder]• Weld inspection [DT (throat thickness)]

STEP9 Outer surface treatment ofwelds

STEP7 Inner surface coating of welds• Pre-treatment for coating• Coating of welds

STEP8 Holing of S/C surface• Holing by means of WJ• Filling of gaps

• Pre-treatment for coating• Coating©International Research Institute for Nuclear DecommissioningNo.26(1) Organization of technical specifications for the advancement of the water circulation system in PCV◼ Procedure for maintenance of S/C water intake part
Inspection

Repair
[Procedure 1] Coating pre-treatment at [Procedure 2] Coating repair at coating
degradation points (inner and outercoating degradation points (inner andsurface of extension pipe)
outer surface of extension pipe)[Procedure 1] VT of extension pipe and S/Cjoint (inner and outer surface of extension pipe)
Temporary storage container

Temporary storage container

Temporary storage container

Duringmaintenance[Application of existing technology]
No.M1a VT
inspection apparatus(inner surface)[Shared with No.C14a] [Shared with No.C14b] [Shared with No.C15a]
No.M2b Surface No.M3a Coating
No.M2a Surface
preparation
preparation apparatus
apparatus (inner
apparatus (for(for coating: innersurface)coating:outersurface)surface)[Application of existing technology]
No.M1b VT
inspection apparatus(outer surface)[Shared with No.C15b]
No.M3b Coating
apparatus (outersurface)

Temporary storage container(Inside the extension pipe)[Procedure 1] VT of extension pipe and S/C joint
Temporary storage container[Procedure 2] Identification of[Procedure 3] Identification of leakage points

leakage points by means of aby means of a leakage test (State of negative

leakage test (air pressurization)**pressure in PCV)

Temporary storage container(Inside the extension pipe)[Procedure 1] Airtightness
inside the extension pipe

Temporary storage container[Procedure 2] Surface
cleaning of leakage points[Procedure 3] Repair ofleakage points[Procedure 4] Postrepair VT

Hoist and installation cart
Temporary storage
container
Pressurization[Application of existing technology]
No.M1a VT inspection
apparatus (innersurface)[Application of existing[Application of existing
technology]
technology]
No.M7 Foaming solution[Application of existing technology]
No.M6 Temporary sealing
apparatus

feederLevel 2

State of negative pressure*: Close the lower end of the extension pipe with a temporary sealing apparatus, and perform a local
leakage test of the S/C water intake part (including the temporary storage container). If leakage isfound, move the apparatus step by step and narrow down the pressurization range to identify theleakage location.

(Outside the extension pipe) [Procedure 2] Identification of leakage points[Procedure 1] VT of extension pipe and S/C joint
Temporary storage container

by means of a leakage test (State of

No.M1a VT
inspection apparatus(inner surface)[Application of existing
technology][Shared with No.C14a]
No.M4a Surface
cleaning apparatus(application of coating
agent: inner surface)[Shared with No.C15a]
No.M5a Coating
application apparatus(inner surface)

No.M1a VT
inspection
apparatus (innersurface)(Outside the extension pipe)[Procedure 1] Surface cleaningof leakage points[Procedure 2] Repair ofleakage points[Procedure 3] Post-repair VT

negativepressurein PCV)
Temporarystoragecontainer[Application of existing
technology][Application of existing
technology]
No.M1b VT inspection
apparatus (outer surface)

No.M6 Temporary
sealing apparatus[Application of existing
technology]

No.M1b VT inspection
apparatus (outersurface)[Application of existing technology]
No.M8 Tracer gas feeder

State of negative pressure[Application of existing
technology]
No.M1b VT inspection
apparatus (outer surface)[Shared with No.C14b][Shared with No.C15b]

No.M4b Surface cleaning
apparatus (application of
coating agent: outersurface)

No.M5b Coating
application apparatus(inner surface)[Application of existing
technology]
No.M1b VT inspection
apparatus (outersurface)©International Research Institute for Nuclear DecommissioningNo.27(1) Organization of technical specifications for the advancement of the water circulation system in PCViii) Identification of development challenges and drawing up of development plans<Apparatus used for establishment of S/C water intake part><Apparatus used for maintenance of S/C water intake part>2

Policy of
response in thisproject▲2▲

No.C10b can be applied

▲

2
3
2

▲
▲

No.C10b can be applied

▲

1

O*

2

△

No.C10b can be applied

▲

1

O*

3

▲

1

O*
▲

Guide ring removal apparatus

0(Since a feasible
outlook was obtained)

3▲

No.C10b Can be applied

▲

2

▲

C15a
C15b
C16
C17

Isolation mechanism
Surface preparation apparatus (forcoating: inner surface)
Surface preparation apparatus (forcoating: outer surface)
Coating apparatus (inner surface)
Coating apparatus (outer surface)
Storage container
WJ holing apparatus

3
2
2
3

▲
▲
▲
▲
▲*

C18

Other common apparatus

No.

Apparatus

C1

C11Interference removal apparatus (FRM)
S/C surface treatment apparatus(peeling off of the coating)
Extra banking removal apparatus (S/C
joints)Marking apparatus
Shape measuring scanner
Extension pipe joint welding apparatus
Weld bead treatment apparatus(for welding extension pipe joints)
Positioning apparatus
Gap measuring apparatus (with DT
function)
S/C surface polishing apparatus(floating rust removal) among the weld
cleaning apparatus
Bead treatment apparatus among theweld cleaning apparatus
Pipe inner surface cleaning apparatus(suction) among the weld cleaning
apparatus
S/C joint welding apparatus

C12
C13

C2
C3
C4
C5
C6
C7
C8

C9
C10a
C10b
C10c

C14a
C14b

C19
C20

Surface cleaning apparatus(Application of coating material: outersurface)Coating apparatus (outer surface)

Applicability ofexisting technology

2: Test targets in this project(Fabrication of simple
apparatus in the fullscale test project for
combination)

Shared with No.C14b▲

Shared with No.C15b▲

No.

Apparatus

M1a
M1b

VT inspection apparatus (inner surface)
VT inspection apparatus (outer surface)
Surface preparation apparatus (forcoating: inner surface)
Surface preparation apparatus (forcoating: outer surface)
Coating apparatus (inner surface)
Coating apparatus (outer surface)
Surface cleaning apparatus(Application of coating material: innersurface)
Surface cleaning apparatus(Application of coating material: outersurface)Coating apparatus (inner surface)
Coating apparatus (outer surface)Temporary sealing apparatus
Foaming solution feeder
Tracer gas feeder

M2a
M2b
M3a
M3b
M4a

M4b
M5a
M5b
M6
M7
M8

2
2

Policy of
response in thisproject▲▲

Shared with No.C14a▲

Shared with No.C14b▲

Shared with No.C15a
Shared with No.C15b▲▲

Shared with No.C14a▲

Shared with No.C14b▲

Shared with No.C15a
Shared with No.C15b
2
2
2

▲
▲
△
▲
▲

Applicability ofexisting technology(Legend)
Applicability of existing technology
3: Can be diverted 2: Can be applied 1: Difficult to apply or not applicable 0:
Existing technology absent but can be designed
Policy of response in this project
O: Prototype unit function test, △: Element test, ▲: Only desk study, □: Design
and manufacturing, - : Out of scope, ( ): Improvement, *: 1/1 scale combination testfor verification of remote workability[Summary of the review of the system and technology for water circulation using S/C]・Examining of required functions for the S/C water intake part・Examining of design specifications and requirements for the S/C water intake part・Layout planning for S/C water intake part・Formulation of work procedures for the establishment and maintenance of S/Cwater intake part・Drawing up of technology development plan for the establishment andmaintenance of S/C water intake part©International Research Institute for Nuclear DecommissioningNo.28

6. Implementation details(1) Examining of technical specifications for upgrading of water circulation
systems in PCV, study of work plan and development planning① Study of the water circulation system and technology for inside D/Wi) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenance planiii) Identification of development challenges and preparation of development plan
② Study of the water circulation system and technology by using S/Ci) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenanceiii) Identification of development challenges and preparation of development plan

(2) Development and verification of element technology for accessing andconnecting inside PCV① Development and verification of element technology required for accessing
and connecting inside D/W②Development and verification of element technology required for accessing
and connecting inside S/C©International Research Institute for Nuclear Decommissioning

(2)①-1 Overall work step plan up to the construction of the water circulation
system inside D/W
⚫

No.29

Study was conducted on the overall work steps during the development and verification of element technology required for accessing andconnecting inside D/W.
Drop in D/W water level (only in 1F-3)
・Up to the level of 1st floor of R/B
Construction of access route inside the
PCV for large-scale retrieval

Pre-conditions for D/W water intake✓

For water intake through the pump pit, it is necessary to lay pipes in the PCV with remoteapparatus.

✓

The access route for large-scale fuel debris retrieval should be used as the route for carrying
the remote apparatus in and out.

Example of access route inside PCV for large-scale retrieval

Removal of interference objects inside
the PCV
Construction ① and operation ofwater circulation system• Installation of vacuum pump outside PCV• Insertion of hose inside PCV• Installation of hose (on the deposits)✓

Multiple ideas have been studied for the access route, and the confinement method for theaccess route is being considered.

✓

The use of the said access route for large-scale fuel debris retrieval is planned to be used as
the carrying-in/out route for the work inside the D/W. Note that this study presumes thatapparatus such as the remote apparatus and pump are carried in by providing an opening toallow the remote apparatus to be carried in, such as by opening the X-1 penetration.

Deposit removal
Construction ② of water
circulation system
Unrolling of pipe inside PCV
Suspension and installation ofsubmersible pump (in the pump pit)
Switching of the water intake pump
(to a pump in the pit)
Access route in PLAN-A#

Operation of the water circulation
system (Water level can be controlled
at the bottom of D/W or lower): Scope of study inthis project

Access route in PLAN-B#

Access route in PLAN-C##: For details on the access routes (PLAN-A, PLAN-B, and PLAN-C), see the reports on Subsidy Project ofDecommissioning and Contaminated Water Management in the FY2014 Supplementary Budgets “Project for
Advancement of Retrieval Method and System of Fuel Debris and Internal Structures” and Subsidy Project ofDecommissioning and Contaminated Water Management in the FY2016 Supplementary Budgets “Advancementof Retrieval Method and System of Fuel Debris and Internal Structures”.

©International Research Institute for Nuclear DecommissioningNo.30(2)①-2 Details of issues in laying pipes inside D/W⚫ Example of establishment of D/W water intake line in 1F-1

機器ハッチ
X-1
(Equipment hatch)（500）[Example of approach to D/W water intake line]••••

Intake the water from the pump pit since the water level is controlled below the D/W bottom.
Install the submersible pumps in the pump pit. (Considering the extent of freedom available to install
the pump outside the PCV)
Install the submersible pumps in different pump pits for the sake of multiplexing.
Install a vacuum pump in front of X-2 in consideration of the failure of two submersible pumps. Install
PCV
shell
a hose at the bottom of D/W.
PCVシェル

LINE_B（3528）（3528）

Water intake
pipe
取水配管

（4758）

Submersible
pump
水中ポンプ

Submersible
pump
水中ポンプ

サンプピットPump pit

Pump pit
サンプピットDetails of part a
180°

X-1
(Equipment hatch)
機器ハッチ

Pipes to thepump pit

LINE_A（4000）

N

LINE_A: About 10 ｍ (About 2 ｍ x About 6 pipes)
LINE_B: About 35 ｍ (About 2 ｍ x About 20 pipes)
LINE_C: About 15 m (About 2 m x About 8 pipes)

Interference objects(must
be removed)
干渉物撤去検討

Details of part baWater取水開口部１
intake opening 1
LINE_A

X-2 (air lock)

1470×640

LINE_B

X-2エアロック(air lock)

Water intake
opening 2
取水開口部２c

1500×970

Vacuum pump

Vacuum
pump
真空ポンプ

b
Water
intake pipe
取水配管
LINE_C0°

Extension pipe fordetailed investigation
inside PCVBoring for detailed
investigation inside PCV

X-6

Extension pipe for detailed

Details of part c

PCV内部詳細調査用ガイドパイプ
investigation inside PCVBoring for detailedPCV内部詳細調査用穿孔部
investigation inside PCV

270°✓ Level 1 facility: Submersible pump x 2 (Water intake position: pump pit) / Via the access tunnel installed at X-1✓ Level 2 facility: Vacuum pump (Water intake position: D/W bottom) / Via the extension pipe installed at X-2©International Research Institute for Nuclear Decommissioning

(2)①-3 Results of detailed study of the method of laying pipes inside D/W andpreliminary test results
ID

The structure should allow connection
using remote apparatus.

Use an auto-lock coupler for easy connection with the remoteapparatus. (Not welded in consideration of replaceability)

O

Method of aligning the connecting
pipesPrepare apparatus (jig) that can remotely attach and detach thecoupler.

O

Method of inspecting the connection
parts

Visually verify leaks in pipe connection parts using a remotesurveillance monitor.

Pipereplacement

When partially replacing a pipe after
the pipe is laid, it is necessary toabsorb the displacement at theconnection parts.

Pump
suspension

Preliminary Element
test
test

O

O

-

Use flexible metal hoses on the ground floor, and pressure-resistantrubber hoses made of radiation environment rubber on the basement
floor.

O

O-

Method of suspending a pipeconnected pump into the pump pit

A remote apparatus for connecting pipes and an auxiliary apparatus
for suspension (mobile lifting machine) are combined to suspend thepump while supporting its own weight.

O

-

O

In order to extend the pipes to thebasement floor, it is necessary toconnect the pipes while the pipes are
suspended.

It is difficult to connect the pipes while they are being suspended, so
suspend the pump and the pressure-resistant rubber hoses made ofradiation environment rubber as a unit.

O

-

O

Connection structure of pipes on thegrating and pipes to the basement floor

Connect the pipes using a coupler.

O

-

O

5

Pump
installation

Method of fixing the pump inside thepump pit

A pump fixing container is set in the pit in advance, and the pump isinstalled on it.
⇒Upon conducting a detailed study, the pump was fixed with a fixing
jig.

O

-

O

6

Pump
replacement
procedure

Study of the procedure for replacing apump installed inside the pump pit

Confirm an optimum replacement procedure through element test.

O

-

O

3

4

•

Desk
study

Proposed solution (Results of detailed study)

-

2

•

Issue details

O

1

•

Item

No.31

Pipe
connection
parts

Connection ofpipes

Remarks

Incorporated
in ID.4

Element tests
conducted

Incorporate
ID.1 and 2

Preliminary tests were conducted to verify the feasibility of the study results for the used pipes, structure of the connection parts, and the inspection
method of the connection parts.
The above study results were incorporated in the element test to verify the feasibility of the pipe and pump installation method inside the D/W bysuspending the pump to the basement floor ⇒ connecting the pipes ⇒ installing the pump.
After verifying the above, the feasibility of the pump replacement procedure was verified through element tests.
©International Research Institute for Nuclear DecommissioningNo.32(2)①-4 Element test plan for the method of laying pipes inside D/W
PCV shell➢ Purpose of the test

Equipment hatch✓ Verification of feasibility of the methods of installing
pipes and pumps inside D/W✓ Verification of feasibility of pump replacement
methodWater intake opening 1

Simulation
scope
Water intake opening 2

Air lock
Vacuum pump

Water intake pipe

➢ Items to be verified✓ Pipe (hose) connection method✓ Pipe (hose) and pump suspension method✓ Pump fixing method✓ Pump replacement method

Extension pipe for detailed investigation inside PCVHoling for detailed investigation inside PCV

Scope of simulation in element tests
Pump fixing jig(simulated
pump)
Simulatedpedestal➢ Expected outcome✓ Feasibility of the method of connecting pipes (hose)
remotely✓ Feasibility of the method of installing (fixing) pumpinside D/W✓ Feasibility of pump replacement method andreplacement procedure

Pump pit
Grating opening

Basement
floor pipes
Utility standCoupler
Ground floor pipes[Entire scope of simulation]©International Research Institute for Nuclear Decommissioning

(2)①-4 Element test plan for the method of laying pipes inside D/W

No.33(2) Element test items, test procedure, and criteria
ID

Test items

Test procedure

Criteria

Pump suspension
and installation(fixed)(1) Use a transport apparatus (gantry lifting machine, etc.) tosuspend a simulated pump with a connected pipe (hose) into
the pump pit.
(2) Fix the simulated pump inside the pump pit using the pumpfixing jig.
(3) Confirm that the simulated pump is fixed.

・A pump with pipes connected can be suspended into
the pump pit and can be installed (fixed).
・The pump installation status can be verified andmonitored with a camera.

2

Connection of pipes

Use a mobile, flexible structured work arm to connect the pipes(hose) on the grating and pipes (hose) connected to the simulated
pump.

・The pipes on the grating and the pipes on thebasement floor can be connected.
・After connection, a flow rate of 10 m3/h is satisfied.
(Note)

3

Pump replacement
procedure (recoveryof pump)(1) Use a mobile, flexible structured work arm to separate thepipes (hose) on the grating and the pipes (hose) connected tothe pump.
(2) Use a transport apparatus (gantry lifting machine, etc.) to lift
and recover the simulated pump.

The pump installed in the pump pit can be lifted andrecovered.

1

Remarks(Note) A simulated pump simulating the dimensions and mass was used for pump suspension, installation, and recovery.
To check the flow rate, the simulated pump was replaced with a pump satisfying 10 m 3/h#, and the flow rate was verified. # Flow rate based on the “system” side requirement.

②Connection of pipes
Mobile lifting machine

Laid pipe

Remote apparatus
Load suspension wire
Metal hose

①Pump suspension and installation

Water intake pipe
Submersible pump

Connection
Suspended pipe

Pump pit©International Research Institute for Nuclear Decommissioning

(2) ①-5 Results of element test

No.34

(1) Pump suspension and installation (fixed): 1/4
Bird’s eye view
camera (A)<Cameras are placed on ground floor>
Camera mounted on gantry
lifting machine + light* Moving with lifting machine

Light
Pump pit(basement
floor)

Camera carriage car(with light)* Moving to random
places

Grating opening

Bird’s eye view camera[B]+light

Grating lowering camera* Moving to random
placesRemote monitoring by using fixed bird's eye view camera and mobile device-mounted camera©International Research Institute for Nuclear Decommissioning

(2) ①-5 Results of element test

No.35

(1) Pump suspension and installation (fixed): 2/4< Cameras are placed on basement floor>

Throwinglight

Water fillingsystem for testingThrowing
light

Pump
pit

Enlarged

Water
filledGrating opening(ground floor)

Basement floor bird's eyeview camera +light

Grating lowering
camera (lowered)

Remote monitoring by using fixed bird's eye view camera and mobile grating lowering camera©International Research Institute for Nuclear Decommissioning

(2) ①-5 Results of element test

No.36

(1) Pump suspension and installation (fixed): 3/4<Major work monitoring method>・During work on the ground floor: Bird’s eye view camera x 2, gantry lifting machine mounted camera and camera carriage car
・During work on the basement floor: Bird’s eye view camera for the basement floor and grating lowering camera

During work on the ground floor (until passing
through pump opening)

Bird’s eye view
camera[B]Bird’s eye view
camera[A]During work on the basement floor (after passing
through pump opening)

Gantry lifting machine mounted
cameraBird’s eye view camera forbasement floor
Gantry lifting machine mounted
cameraBird eye view camera[B]Grating lowering camera
Basement
floor

Ground floor

Camera carriage car

Bird's eye view
camera for basement
floor

Bird’s eye
viewcamera[A]Bird's eye view camera[B]

Camera setting©International Research Institute for Nuclear Decommissioning

(2)①-5 Results of element tests(1) Pump suspension and installation (fixed): 4/4
Ground floor

Hose (basement
floor pipe)

No.37

Gantry liftingmachineBasement floor Bird's eye view camera forbasement floor

Pump
fixing jig

Bird's eye view
camera [A]Wire
Bird's eye view camera [B]

STEP

Pump (simulated
pump for testing)

Camera installation<Test results>

1. Transport the pump to the opening
Basement
floor pipe

Pump fixing jig

Gantrylifting
machine2. Suspend the pump from the opening

Grating openingWork
statusHose drum

STEP

Image from the bird's
eye view camera [B]Pump(simulation)

3. Suspend to the basement floor

Image from the bird's
eye view camera [A]Image from the gantry liftingmachine mounted camera

4. Install the pump in the pit

Grating openingWork
statusOffset by flexible
structured workarm
Flexible structured
work arm
Image from the basement floor
bird's eye view camera

Pit

Image from the basement floor
bird's eye view camera

It was confirmed that the pump can be installed in the pit by remote operations©International Research Institute for Nuclear Decommissioning

(2)①-5 Results of element tests

No.38
Pipe

(2) Connection of pipes: 1/2
Ground floor

Pipe
Bird's eye view camera [A]V-groove
Bird's eye view camera [B]Utility standPipeconnecting jig<Test results>

Camera installation

STEP

1. Draw the basement floor pipe
Flexible
structured workarm

2. Install the basement floor pipe on the utility stand

Hose
HolderGrating
openingWorkstatusHose drum
Remove the hosefrom the hose drum

STEP

Flexible
structured
work arm tip

Image from the bird’s
eye view camera [B]Image from thecamera carriage car

3. Close the holder and fix the pipe

4. Install the pipe connecting jig to connect the pipes
Arm tip

Arm tip

Pipeconnecting jig
Lockmechanism(Note)

Work
statusHolderImage from the camera carriage car

Hose

HolderImage from the grating lowering camera

Pipe
connecting jig

Image from the camera carriage car

It was confirmed that the basement floor pipe (hose) and ground floor pipe can be connected byremote operations.
(Note) Lock mechanism: Holder is locked by turning the knob.

©International Research Institute for Nuclear DecommissioningNo.39(2)①-5 Results of element tests(2) Connection of pipes: 2/2

Leakage<Results of flow rate and leakage verification>
・The pump in the pit was replaced from a simulated pump to a pump satisfying 10 m3/h.
・The flow rate was confirmed to be 14.4 m3/h.
・Absence of leakage from the pipe connection parts was remotely verified.

Example of leakage

Grating lowering
cameraCameracarriage car

Equipment layout

HolderImage from the camera carriage

Utility standImage from the grating lowering camera
Specifications for submersible pump・Model: 50PN21.5 (Tsurumi Manufacturing)・Discharge rate: 12 m3/h・Total pump head: 14.5 m
・Dimensions: 196 x 295 x 435 mm
・Weight: 15.9 kg

When directly verified

It was confirmed that the specified flow rate is satisfied and that remotely monitored
images allow monitoring that is almost the same as direct verification.
©International Research Institute for Nuclear Decommissioning

(2)①-5 Results of element tests

Basement
floor

Groundfloor

No.40
Bird's eye view camera forbasement floor(3) Pump replacement procedure
Bird's eye view
camera [A]

Bird's eye view camera [B]<Test results> #Camera installation and work monitoring method is the same as that for pump suspension.

STEP

1. Disconnecting the basement floor pipe
Arm tip

Hose drum

2-1. Lifting and recovery of pump (basement floor)

Attach the hoseto the hose drum

Flexible
structured workarm
(Offset)Gantry liftingmachine hanger

Flexible
structured
work arm
Image from the bird’s
eye view camera [B]Work
statusPump fixing jig

Image from thecamera carriage car

STEP

Camera installation

Image from the gantry liftingmachine mounted camera

2-2. Lifting and recovery of pump (ground floor)

Fix the pump fixing jig to
the gantry liftingmachine hanger

Image from the grating lowering
cameraImage from thebasement floor bird
eye view camera

3. Transport the pump with the transport apparatus
Gantry liftingmachineHose drum

Grating
opening

Pit

Hose drumWork
statusImage from the gantry liftingmachine mounted camera

Image from the bird’s
eye view camera [B]Image from the bird’
eye view camera [B]Image from the bird’s
eye view camera [A]It was confirmed that a remotely installed pump can be recovered.
©International Research Institute for Nuclear DecommissioningNo.41(2)①-5 Results of element tests(4) Summary of test results
ID

Test items

Criteria

Test results

Remarks

Pump suspension and installation(fixed)・A pump with pipes connected can besuspended into the pump pit and can beinstalled (fixed).
・The pump installation status can beverified and monitored with a camera.

・The test results confirmed that a pump with hose connected
can be suspended into the pump pit by a gantry lifting machine,and can be installed in the pit (pump is fixed by a pump fixing jig).
・The test results confirmed that the pump installation status canbe verified (monitored) by means of the basement floor bird's
eye view camera.

2

Connection of pipes

・The pipes on the grating and the pipeson the basement floor can be connected.
・After connection, a flow rate of 10 m3/h issatisfied. (Note)

・The test results confirmed that the pipes laid on the grating
and the hose connected to the pump on the basement floor canbe connected with a flexible structured work arm and pipe
connecting jig.
・The test results confirmed that the flow rate after connection is
14.4 m3/h which satisfies the specified flow rate.

3

Pump replacement procedure(recovery of pump)

The pump installed in the pump pit can belifted and recovered.

The test results confirmed that the pump installed in the pump pit
can be lifted out and recovered by a gantry lifting machine.

1(Note) A simulated pump simulating the dimensions and mass was used for pump suspension, installation, and recovery.
To check the flow rate, the simulated pump was replaced with a pump satisfying 10 m 3/h, and the flow rate was verified.

Pump suspension and installation

Connection of pipes

Recovery of pumpSince all the criteria were satisfied, the feasibility of the methods of installation andreplacement of pipes and pump inside the D/W was verified.
©International Research Institute for Nuclear DecommissioningNo.42(2)①-5 Element test results and issues(5) Test schedule
Items

Second half of 2018
…

Jan

Feb

Mar

First half of 2019
Apr

May

Jun

Jul

Second half of 2019
Aug

Sept

Oct

Nov

Dec

Jan

Feb

Mar

(1) Conceptual study on methods(2) Conceptual design of apparatus① Structure of connection parts② Structure of jigs

③ Structure of auxiliary apparatus(3) Element test
① Test plan
② Basic and detailed design ofapparatus③ Fabrication and preliminary testof apparatus④ Element test
⑤ Evaluation of test results[Legend]Plan:
Actual:©International Research Institute for Nuclear DecommissioningNo.43

6. Implementation details(1) Examining of technical specifications for upgrading of water circulation
systems in PCV, study of work plan and development planning① Study of the water circulation system and technology for inside D/Wi) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenance planiii) Identification of development challenges and preparation of development plan
② Study of the water circulation system and technology by using S/Ci) Organizing technical specifications considering the site environmentii) Study of access route establishment work and maintenanceiii) Identification of development challenges and preparation of development plan

(2) Development and verification of element technology for accessing andconnecting inside PCV① Development and verification of element technology required for accessing
and connecting inside D/W② Development and verification of element technology required for accessing
and connecting inside S/C©International Research Institute for Nuclear DecommissioningNo.44

6. Implementation details(2) Development and verification of element technology for accessing andconnecting inside PCV② Development and verification of element technology required for accessing andconnecting inside S/C
1) Development and verification of marking apparatus, positioning apparatus, and gap
measuring apparatus2) Development and verification of S/C surface polishing apparatus, weld beadtreatment apparatus, and S/C joint welding apparatus3) Development and verification of temporary sealing apparatus4) Schedule for the development of technology for establishment of S/C water intake
part©International Research Institute for Nuclear DecommissioningNo.45(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C[Purpose]
Establishment of element technology for the establishment andmaintenance of S/C water intake opening[Issues]1) Development and verification of marking apparatus, positioning
apparatus, and gap measuring apparatus2) Development and verification of S/C surface polishing apparatus,
weld bead treatment apparatus, and S/C joint welding apparatus3) Development and verification of temporary sealing apparatus[Overview of results]
1) Development and verification of marking apparatus, positioning
apparatus, and gap measuring apparatus◼ Procedure for aligning the S/C water intake part・ Insertion/ welding/ inspection of extension pipe・Creation of a 3D model of the S/C surface(bottom/ middle/ top)・Processing of the grooves at the bottom of・Measurement of S/C surface
The shape of the S/C surface was measured
the extension pipeby mounting a shape measuring scanner on
Based on the shape measurement results
the installation cart.
obtained by scanning, the contact surface of the[Diversion of existing technology]
extension pipe (bottom) with the S/C surface
No.C5 S/C surface
was processed. (Factory work)measuring apparatus

3D model of ideal
extension pipe

Plumb bob
3D model of S/C surface

A transport cart with a mounted extension pipe was carried in. The
installation cart and the transport cart were connected, theextension pipe (bottom) was lowered with the hoist of theinstallation cart, and temporarily placed on the base plate. The
extension pipe (middle) was placed on the extension pipe (bottom)
and visual testing and dimensional testing of the welding and welds
was conducted. The same process was followed for extension pipe(top) as well.
[Application of existing technology]
No.C6 Extension pipe joint
welding apparatus:Marking on S/C surface (plan):Plumb bob:3D model of S/C surface:3D model of ideal extension pipe
:Marking on inner surface ofextension pipe (plan)

Extension pipe
(top)

[No.C10b can be applied]
No.C7 Weld beadtreatment apparatus: Marking (plan): Plumb bob: Extension pipe (planned installation position)
・Preparation work for positioning of the extension pipe
An positioning apparatus (positioning tool) was installed andconnected to the extension pipe. Thereafter, the extension pipe
was installed on the S/C. A gap measuring apparatus (including
a hand-held scanner) was inserted to obtain the positional
relationship (amount of deviation) between the extension pipe
and the S/C prior to positioning.

3D model of the S/C surface

Extension
pipe

Hand-held
scanner
3D model of the lower endof the extension pipe
3D models compared on the basisof markings (x)Superimposition of the 3D model of the S/C surface and the 3D model of the lower end of the extension pipe

◼ Setting the target accuracy for positioning
Items

FactorTargetaccuracy

Maximum
gap
estimated

Remarks(1) Measurement error in comparison with the ideal shape of the lower end of the extension pipe
① Measurement of S/C surface

Measurement±0.5 mm

1.0 mm

② Creation of a 3D model of the
S/C surface

Model creation(Beingconsidered)

1.0 mm[Target]③ Processing the grooves at thebottom of extension pipe

Processing±1.0 mm

2.0 mm④ Peripheral welding ofextension pipes

Processing(remote)-No impact

Measurement(Model)±0.05
mm0.05 mmApparatus driving
force (Minimum
movement unit)

0.5 mm

0.5 mm±0.05
mm0.05 mm① Measurements by the handheld scanner (Preparation work)② Positioning

No.C8 Positioning
apparatus (Positioning
tool)

No.C9 Gap measuringapparatus (Including
hand-held scanner)

Method of calculating the amount of deviation of the extension pipe

①Lower the extension pipe on to the S/C.
②Use a hand-held scanner (3D) to acquire the scan data of the entire circumference on the inside of theextension pipe and create a 3D model of the lower end of the extension pipe (including the S/C surface).
③Superimpose the 3D model of the lower end of the extension pipe created by the hand-held scanner(procedure ② above) and the 3D model of the S/C surface created by the shape measuring scanner, andcheck the amount of deviation in the 3D position and inclination of the extension pipe (x, y, z axis x total 6
items of translation and rotation).
④Based on the confirmed amount of deviation, determine the amount of movement to be input into thepositioning tool.

Specific modeling method isdetermined by using a 1/1 scale
combination test

Bending occurs due to welding
deformation, but it is within theadjustable range of thepositioning apparatus.

(2) Positioning of extension pipe

・Positioning of the extension pipe・Measurement of extension pipe gaps
The hand-held scanner was pulled up and using the positioning The monitoring tool was pulled up and the hand-held scanner
apparatus (monitoring tool) instead for observation, thewas inserted. The entire circumference of extension pipe andextension pipe was moved (translation/rotation) based on the
S/C surface was measured, and it was confirmed that there
numeric values obtained by the previous procedure, and the gap were no gaps of 5 mm or more that cannot be welded.
was set to less than 5 mm.

<See the box on the top right for the method of calculating the amount of deviation of the extension pipe >No.C8 Positioning
apparatus (Positioning
tool)

•

(3) Measurement of extension pipe gaps
① Measurement of extension
pipe gaps
Hand-held scanner

Total

Measurement(Model)4.60 mm

5.0 mm [Target gap]

No.C8 Positioning apparatus(Monitoring tool)⇒From the target gap of 5 mm, set the target accuracy of eachprocess in this way.
©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼

Specifications of positioning apparatus

Items

Specifications
Gear rotatingaround Z axis
Rotation
RZ

Translation /rotation center
Rotation RZ Translation
around Z
X
axis
Translation(Crest side)Y

Motor driving in the Z axis
direction (x3) [Rotation Rotation RX
around X axis and Y axis] Rotation RY
Translation
Z
Ring rotatingaround Z axis

Configuratio
n ofapparatus

Remarks

Motor driving in the
X axis direction
Translation
Positioning tool
X

Motor driving in the
Y axis direction
Translation
Y

Extensionpipe

Laser assembly(Troughside)
Translation
Translation Translation
Z
X
Y

CameraExtension pipe fixing
location (enlarged)
Connecting plates (x3)MagnetImage of the operation ofadjusting Rotation RX,
RY (Translation Z)

Monitoring tool
Ball screw (x3)Basicfunctions(1) The gap at the bottom of the extension pipe can be adjusted to 5 mm or less.
(2) The upper part of the extension pipe can be fixed and the entire weight ofthe extension pipe can be supported.
(3) It is possible to adjust the 3 translational axes (X, Y, Z) and 3 rotational axes
(RX, RY, RZ) of the extension pipe by remote operations.
(4) The camera of the monitoring tool can be fixed on the S / C by remote
operations.
(5) When adjusting positions remotely, it is always possible to check whether
the gap between the lower end of the extension pipe and the S/C is 5 mm orless for multiple representative directions.
(6) The extension pipe can be removed after welding[Overview of positioning apparatus]

No.46◼ Unit function test of positioning apparatus Positioning tool
⚫ Purpose of the test
Simulated 1st floor of R/B

To grip the flange at the upper end of
the extension pipe with the prototype
positioning apparatus (positioning tool,
monitoring tool) for the establishmentof the S/C water intake structure, andalign it, using an extension pipe
simulating the actual shape and an
S/C test specimen, and to confirm thatthe extension pipe can be set within
the specified gap.

Rotation RY Rotation RY
around Y
around Y
axis
axis

Simulated extension pipe

Monitoring tool

Simulated S/CDistance between the centers of
S/C and extension pipe

Simulation scope

1st floor of R/B – Hole diameter

Remarks

650 mm

1st floor of R/B – Flatness

No floor slope

Distance between 1st floor of R/B - S/C

About 4100 mm

Equivalent to 1F-3

Distance between the centers of S/C andextension pipe

1500 mm

Maximum distance for the sitewhere water intake part isplanned to be constructed #1

Inner radius

4450 mm

Equivalent to 1F-2/3

15.9 mm

Actual: 17 mm◼ The positioning apparatus is a device used to remotely alignS/C
Thicknessthe extension pipe to the gap between the S/C surface andMaterial
the extension pipe with a threshold limit value of 5 mm or lessOuter diameterfor the welding work before welding the S/C surface andInner diameter
extension pipe.
Material◼ The positioning apparatus comprises the positioning tool andLower end
monitoring tool. These tools are connected to the control
Shapepanel with a cable, and can be operated remotely by operating
Extension
the touch panel, levers, and switches on the operation panel
pipe
Outer diameter
while checking the monitor screen output from the apparatus.
Other thanst
• Positioning tool: This apparatus is installed on the floor of 1
Inner diameter
Positioning tool
lower end
floor of R/B. It is fixed with connecting plates at 3 points ofMaterial
the apparatus and the upper end flange of the extension
FlangeOuter diameter
pipe, gripping the extension pipe, and adjusts the position of
Structure (welds)
the lower end of the extension pipe by translation (X,Y,Z)
and rotation (X,Y,Z) of each axis by the driving power of theTorus room interference objects
servo motor.
• Monitoring tool: An apparatus that is installed on the surface
Environment (Brightness, temperature,of the S/C in the extension pipe and monitors and verifies
humidity)
the gap between the extension pipe and S/C surface withnine cameras mounted on the camera box
Monitoring tool Monitor, operation panel

Carbon steel
540 mm
521 mmActual: 520 mm

Carbon steel
On-site processing withgrinder in accordance with
S/C simulation

Actual: NC processing based onscan data

559 mmActual: 552 mm#2

521 mmActual: 520 mm

Carbon steel

Actual: Stainless steel

720 mmNot simulatedInterference objects
assumed to have been
removedNot simulated©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C
⚫

No.47

Unit function test of positioning apparatus (Details and results) (1/2)
No.

Test details

Items to be verified(Criteria)

0Lift the extension pipe with a crane, insert atemporary support material between theextension pipe and the hole on the floor,
temporarily fix the extension pipe, andremove the extension pipe from the crane.

-

-

1

Use the crane to install the positioning tool.
The installation position should align withthe markings provided on the floor inadvance.

Positioning tool can beinstalled. (Check forinterference with theextension pipe andtemporary support material)

Good

2

Verify the installation position of thepositioning tool, and fix the positioning tool
to the floor with bolts.

3

Remove the rod that connects theconnecting plates, and rotate the threeconnecting plates 180°. Raise theconnecting plates until they touch the flange.
After that, fasten the connecting plates andthe flange with bolts.

4

Raise the positioning apparatus and remove
the temporary support material that
temporarily fixed the extension pipe and thefloor surface, while monitoring that theindicated value of the load cell does notexceed the allowable load.

Temporary support material
can be removed

Good

5

Use a crane to lower the monitoring toolfrom the top of the positioning tool along theinner surface of the extension pipe.

Monitoring tool andextension pipe do notinterfere with each other.

Good

6

Seat the monitoring tool camera box on the
S/C surface.

Visually checking with acamera that the monitoring
tool can be seated on the
S/C surface.

Good

7

Perform positioning by making fineadjustments while checking the gaps ineach direction on the monitor image output
from the camera of the monitoring tool.

Positioning operation ispossible while monitoringwith the camera of themonitoring tool.

See
below

-

Positioning tool andextension pipe can beconnected.

Test
Remarks
results

Temporary fixing of extension pipe withtemporary support material (No.0)

Installation of positioning tool (No.1)

Lowering of monitoring tool (No.5)

Seating the monitoring tool on the
S/C surface (No.6)

Good

Good

No.7 Test results: Good
The positioning is performed to reduce the amount of gap while checking the four
directions at every 90° on the monitor and using the align mark set in advance asa key. It was possible to reduce the amount of gap while making fine adjustments.
This procedure was completed because the amount of gap could be adjusted to
be as small as possible visually on the monitor.

Monitoring of extension pipe-S/C surface
with monitoring tool (No.7)©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C
⚫

No.48

Unit function test of positioning apparatus (Details and results) (2/2)
No.

Test details

Items to be verified(Criteria)

Testresults

8(Verification of gap distribution by laser
line)
After positioning, confirm that the gap
between the S/C surface and the lower
end of the extension pipe is 5 mm or lessby comparing the distance between thelaser lines of the monitoring tool placed at
5 mm intervals on the monitor screen ineight directions.

It is possible to determine
whether the gaps on the monitor
screen are 5 mm or less by using
the 5mm-interval laser lines as areference.

Good

9

Pull up the monitoring tool with a crane.

Monitoring tool and extension
pipe do not interfere with eachother.

Good

10

Measure the gap between the S/C and
the inner surface of the extension pipe infour directions with a clearance gauge.

Measured gap is 5 mm or less.

Good

11

After fixing the lower end of the extension
pipe to the S/C surface by temporary
welding in four directions, insert atemporary support material between theextension pipe and the hole on the floor
and temporarily fix it, and then use acrane to remove the positioning tool.

Direction(°)
0

No.8 result(mm)

Positioning tool can be installed.
(Check for interference with theextension pipe and support
material)

No.10 result(mm)

No.8 Test results:
0.8
Good

Remarks

Reference laser lines*

Condition of extension pipe - S/C
surface after positioning (No.8)
Good⚫
Criteria

Test
results

0.6

45

0.3

-

90

0.9

0.9

135

1.5

-#

180

1.5

1.4

225

0.8

-

270

0.7

0.7

315

0.6

-

# Maximum gap is 1.8 mm in 135° direction■No.8
Gap of 5 mm or lesscan be determinedfrom the monitor
screen.
■No.10Gap is 5 mm or less.

Verification status on the monitor screenof the monitoring tool: Near 90° (No.8)

Good

Summary*: Laser line intervals are measured
in advance before the extension
pipe is inserted.

• It was confirmed that the basic functions of positioning apparatus
are satisfied.
• It was confirmed that with the extension pipe positioning method, inwhich fine adjustments are repeated to make the gap smaller, using
the align mark set in advance and visually checking the image fromthe monitoring tool camera, the gap between the S/C surface andextension pipe can be adjusted to 5 mm or less (test result is lessthan 2 mm).
• Matters reflecting a full-scale test based on the results of the unit
function test
➢ The following procedure includes in the procedures of full-scale
test: If the gap in the extension pipe positioning is large based on
the amount of deviation calculated from the hand-held scan results
adjust the gap to 5 mm or less by visually checking the positioning
using the image from the monitoring tool camera just like in the unit
function test.
©International Research Institute for Nuclear DecommissioningNo.49(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼

◼

Specifications of gap measuring apparatus
Items

Specifications

Remarks

Scope ofelement test

Carrier
assembly
Configurationof apparatus

In this project,element test is
only
performed forthe hand-heldscanner (3D)
without
developing anapparatus.

Hand-held scanner (3D)

Extension pipe

Hand-held scanner

Element test of gap measuring apparatus⚫ Purpose of the test
The gap measuring apparatus is an apparatus that remotely performs the following
tasks while welding the S/C and extension pipe, from among the work for theestablishment of the S/C water intake part structure:a. Measurement of the amount of deviation of the extension pipe (Identification of
the position and bearing of the lower end of the extension pipe before
positioning)b. Measurement of the gap (Verification that the gap between the S/C surface andthe lower end of the extension pipe before welding is at the tolerance value of 5mm or less)c. Weld dimensional testing (Verification that the weld throat thickness after welding
has the required dimensions)a. Measurement of the amount of deviation of the extension pipe
3D models in 1. and 2. are comparedbased on the markings (x) to calculate theamount of deviation

Basicfunctions•(1) The hand-held scanner (3D) can be lowered to the specified position for installation,
fixing, and recovery by remotely operating the carrier assembly.
(2) The gap can be verified by shape measurement of the S/C surface and the entire
circumference of the lower end of the extension pipe by means of a hand-heldscanner (3D).
(3) The throat thickness of the fillet weld can be verified by shape measurement of the
S/C surface and the entire circumference of the lower end of the extension pipe bymeans of a hand-held scanner (3D) before and after welding.
(4) The marking positions on the S/C surface and the inner surface of the extension
pipe can be verified.
(5) The accuracy of dimensional measurement by means of the hand-held scanner(3D) is ± 1 mm or less.

Specifications of hand-held scanner

1. 3D model acquiredwith a hand-heldscannerb. Measurement of the gap
Calculation of gap on
the acquired 3D
Extension pipe
model
InsideOutsidethe pipe
the pipe

3D model acquired witha hand-held scanner
A perpendicular line is drawn
between the S/C surface and thelower end of the extension pipe tocalculate the gap

2. Ideal 3D model ofthe lower end of theextension pipe

• Performance evaluation through element test
Since performance evaluation is carried out by acquiring a 3D model ofthe measurement point (between the lower end of the extension pipe andthe S/C surface) using the hand-held scanner, which is the main
component of the gap measuring apparatus, the following performance
evaluation is carried out by means of element tests using the hand-heldscanner alone:

Light source

LED (blue)

3D resolution (maximum)

0.1 mm

3D accuracy (maximum)

0.05 mm

Photographable range

200-300 mm

Photographing range (shortest distance) (height x width)

90 x 70 mm

Photographing range (longest distance) (height x width)

180 x 140 mm

1) Evaluation of measurement accuracy by manual scanning

Photographing range (angle) (height x width)

30 x 21 deg

2) Evaluation of photographing range by scanning with a rotating jig

Main unit dimensions (height x depth x width)

190 x 140 x 130 mm3) Evaluation of marking

Main unit weight

0.85 kg4) Evaluation of throat thickness

c. Weld dimensional testing (DT)Extension pipe
InsideOutsidethe pipe
the pipe
Throatthickness

The 3D models before and after
welding are compared anddimensional testing is conducted.

(Supplement) The hand-held scanner is an apparatus that builds a 3D model by processing the scanned image data at high speed, recognizing the geometric features of the object
to be measured, automatically integrating the data, and superimposing the data to accurately capture the shape of the subject.

©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/Cii) Evaluation of photographing range by scanning with a rotating jigi) Evaluation of measurement accuracy by manual scanning[Purpose of the test]
To manually scan a test specimen provided with a gap (4,5,6 mm) in advance and check the possibility ofscanning based on the surface condition and verify the 3D model acquired from the scan data. In addition,
to compare the gap measured on the 3D model acquired from the scan data with the gap measured with astraightedge.
[Test conditions]・Shape of test specimen: S/C [saddle type], extension pipe [half cylinder]・Surface condition of test specimen: With buffing, without buffing [2 conditions]・Measurement position: 45°, 90°, 135° (3 directions)・Illumination: Test specimen is covered with a blackout curtain (measurement with scanner
lighting only), normal lighting (existing factory lighting) [2 conditions][Criteria]
a. The end of the lower end of the extension pipe simulation can be confirmed on the 3D model acquired
from the scan data.
b. The S/C surface can be confirmed on the 3D model acquired from the scan data.
c. The gaps can be measured on the 3D model acquired from the scan data.
d. The difference between the 3D model acquired from the scan data and the measured values is ±1
mm or less.
With/ without
Scan data
Illumination[Test results]
buffing
NormalHeightWithout
buffing
Blackout
curtain1
Green part:

Test specimen (Without buffing)

2

144

3
NormalBlackout
curtain

Surfacecondition

Illumination

Gap
4 mm

Normallighting

5 mm
6 mm

Without
buffing

4 mmBlackout
curtain

5 mm
6 mm

4 mm
Normallighting

5 mm
6 mm

With
buffing

4 mmBlackout
curtain

Test specimen (With buffing)Result a Result b Result c Result d #1: There is a 3D model
defect at 180° on the
NG#1
NG#1
NG#2
S/C surface.
#2: Peripheral data
Good
Good
Good
complements the shape
NG#1
NG#1
NG#2
determination of the
Good
Good
Good
Good
defective part in the S/Cmodel.
NG#1
NG#1
NG#2
#3: Gap is not measured
Good
Good
Good
because there is a 3Dmodel defect on thelower end of theextension pipe and the
S/C surface, and the
NG#3
NG#3
-#3
-#3
reliability is low.

5 mm

6 mm
[Conclusion]・ In manual scanning, there is a defective part on the S/C surface (180°: trough side) without buffing,
and there is a defective part in the 3D model over a wide area of the extension pipe and S/C surface
with buffing.
➢ Handling full-scale test (Results will be reported in the full-scale test project)・If the scan data of the S/C surface is missing, the peripheral data complements the shape determination.
・To avoid the effect of a glossy finish, avoid photographing immediately after buffing and shoot at an angle to themeasurement point instead of the front.

Eccentricity

Mounting
angle(horizontal)

30

50

0

280°~60°50

25

270°~100°50

45

0°~130°80

Complementation of S/C surface

Withbuffing

No.50[Purpose of the test]
To use a rotating jig to manually rotate a test specimen provided with a gap (5 mm) in
advance and scan the entire circumference, and confirm that the part to be measured is within
the photographing range of the hand-held scanner, and to change the rotation axis position
Eccentricity(eccentricity), scanner mounting angle (horizontal/ vertical), and scanner installation height asparameters.
[Test conditions]・Shape of test specimen: S/C [saddle type], extension pipe [pipe]
・Surface condition of test specimen: Without buffing
Height・Illumination: Normal lighting (existing factory lighting)[Test parameters]・Rotation axis position (eccentricity)
・Hand-held scanner mounting angle
・Hand-held scanner installation height[Criteria]
a. Parts to be measured (scanned) can be photographed when scanningwith a rotating jig (3D model can be constructed.)
Mounting angle
b. The difference between the gap value in the 3D model acquired from the(vertical)
scan data and the gap measurements from the clearance gauge is ±1
mm or less.
Mounting angle(horizontal).
[Test results] a. Scan condition parameters and photographable range
Mounting
angle(vertical)

Photographable
range

Rotating jig, test specimen

4

180

80

50

45

240°~140°

5

200

80

50

45

240°~140° ①Comparison between scan data and 3D CAD

6

80

50

45

50°~290°

7

100

20

50

110°~210°

8

130

20

50

120°~230°20

50

120°~230°

180° direction– S/C
90° direction defective part

9
10

230

150

11

205

12

20

60

130°~220°2060

130°~220°055

140°~210°50

90°~230°1380
30
b. Results of comparison of gap measurements

270° direction

Scan data (superimposed)
3D model ofextension pipe

Direction(°)① Gap value from
3D model (mm)② Gapmeasurements
(mm)

①-②
(mm)

Result

０

3.0

4.0

-1.0

Good

90

2.7

4.7

-2.0

NG

180

2.8#

2.5

0.3

NG#

270

4.7

5.1

-0.4

Good

3D model of S/C
surfaceGreen part: Complementation of
S/C surface#: There is a 3D model defect on the S/C surface (180°), and the peripheral data complements the shape determination of the defective part.

[Conclusion]・In scanning with a rotating jig, since there is a defective part on the S/C surface (180°) without buffing (Same as(1)), and the 90° scan data for the lower end of the extension pipe is inadequate, the margin of error between
the 3D model and the measured gap value is more than ±1 mm.
➢ Handling full-scale test (Results will be reported in the full-scale test project)・If the scan data of the S/C surface is missing, the peripheral data complements the shape determination. (Same as (1))
・ If the scan data of the lower end of the extension pipe is missing, the position for the missing range is complemented withthe 3D model acquired in advance.
・Further expand the scan conditions (mounting angle, position) for this test in order to collect sufficient scan data

©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C

No.51iv) Evaluating the throat thicknessiii) Evaluation of marking[Purpose][Testing purpose]
To superimpose the 3D models obtained from the scan data before and after welding on the test specimen
To make markings on the flat plate and check the markings with the 3D model obtained from scan data.
used in the unit function test (STEP 3) of S/C joint welding apparatus, check the possibility of measuring theAssuming the marking of the actual equipment, the types of the markings were used as the test parameter.
throat thickness, and compare with the actual throat thickness measurement of the positions where cross・Types of markings: scribing, magic marker (red, black, white), magnet，punching
Simulated lower end ofsectional macro-observation were performed after welding.
[Testing conditions] ・Shape of specimen : Flat plate
extension pipe
[Testing conditions](circumference)・Simulated surface condition of S/C: Without buffing
・Shape of test specimen: S/C [Saddle type], Extension pipe [pipe]・Illumination: Normal lighting (existing factory lighting)Throat[Criteria](Same test specimen as that used in unit function test of S/C joint welding apparatus)
thicknessa. Can check the marking using the 3D model obtained from the scan data.
Welded portion
・Surface condition of specimen : With buffing
b. Accuracy as a result of blurring: The range (maximum / minimum width) difference with respect・Illumination: Normal lighting (existing factory lighting)to another reference is within 1 mm.
・Amount of gap: 0 mm, 5 mm (1500 mm position) [2 conditions]
Scribing
Magic marker
Magnet(Enlarged)

Ideal reference point(Intersections and corners are thereference)[Test results]
Scribing

Magic marker(red)

Magic marker(white)Scan data image(Intersections and corners become wider
due to blurring)

Direction

Magic marker(black)Result a

Result b

Result c

Good

Good

NG

Evaluation of throat thickness

Punching

Magnet3D scan results(0° in the case ofcross section)[Criteria]a. Surface of the welded portion after polishing is photographable.
(Can build a 3D model)
Referenceb. Can measure the throat thickness by superimposing 3D models (superimposed before
and after welding)obtained from scan data before and after welding.
Simulated S/C (forc. The margin of error, when the throat thickness measured with a 3D
extension pipe
model obtained from the scan data before and after welding and thecircumference)
actual throat thickness measurement of the cross section cut out duringcross-sectional macro-observation are compared, is ± 1 mm or less.
[Test results]

Throat thickness (Amount of gap: 0 mm)

Throat thickness (Amount of gap: 5 mm)Modelmeasurements

Modelmeasurements

Actualmeasurements

ResultActualmeasurements

Weld bead

ResultExtension pipe
(before welding)0°19.9 mm

19 mm

Good

17.3 mm

18 mm

90°

19.1 mm

19 mm

Good

15.3 mm

17 mm

NG

180°

20.0 mm

20 mm

Good

16.6 mm

17 mm

Good

270°

21.0 mm

20 mm

Good

18.2 mm

19 mm

Good Gap

Good

S/C (after
welding)

ThroatS/C (before
thickness
・With a throat thickness of 5 mm, the margin of error between the 3D model measurements andwelding)(3D scan)the actual measurements partially deviates from the decided value (within ± 1 mm).
(Cause)Actual3D model3D modelIt is presumed that the cause of this margin of error is that welding deformation
measurements
Marking method
Result a, b
measurement ameasurement b
is not taken into consideration by the 3D models before and after welding.
(Reference)
Extension pipeMarking
It is believed that the gap becomes narrower due to welding deformation. So,
S/C surface
Scribing
87 mm
85.9 mm86.3 mmthroat thickness before welding deformation (model measurement) tends to beThroat thickness(Aftercalculatedusing
welding
smaller than that (actual measurement) after welding deformation.
Magic marker red
122 mm121.6 mm122.6 mmthe model
deformation)(Measures) Not required
Actual throat
Magic marker black
154 mm
154.0 mm
154.4 mmthickness
Good
Extension pipe
(It is difficult to estimate the extent of this welding deformation inmeasurement
Magic marker white
184 mm183.3 mm
183.9 mmwelding deformation
advance and measure it from the inner surface of the pipe.
GapMagnet
227 mm226.3 mm226.6 mm
However, it is believed that the gap becomes smaller due toGap (After welding)(beforewelding deformation, and the throat thickness measurement by the welding)Punching
295 mm293.7 mm294.1 mm
S/C
3D model is always conservative compared to the actual throat(before welding
S/C welding deformation
deformation)
thickness, and can be used in DT.)
Image of throat thickness measurement[Conclusion] ･ The visibility of magnet or magic marker (especially white) was good, and the visibility ofusing 3D scan with a gap of 5 mm
[Conclusion]scribing line or punching was difficult as it was glossy and had few irregularities.
・ Throat thickness can be measured by comparing 3D models before and after welding.
･There was no difference seen in accuracy due to blurring in each of the markings and the・ With a test specimen having a gap of 5 mm, the effect of the gap becoming smaller due to welding deformation
target values were satisfied.
after welding cannot be taken into consideration, and the model value tends to be smaller than the actual
measurement. However, as the results of throat thickness measurement are conservative, the current process➢ Response to full-scale tests: Use magnet or magic marker (white) that are easy for confirmation.
will be continued.

Marked test

©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C

No.52

2) Development and verification of S/C surface polishing apparatus, weld bead treatment apparatus, S/C joint welding apparatus◼ Specifications of S/C surface polishing apparatus◼ Specifications of weld bead treatment apparatus[Overview]
It is an apparatus that polishes the locations on the extension pipe and S/C surface planned to
be welded by means of buffing, before welding the extension pipe (after peeling off the coatingfrom the S/C surface) and removes the loose rust on the S/C surface.
With the S/C surface and extension pipe about 500 mm apart, the apparatus is fixed inside theinner surface of the extension pipe and used.
Items

Specifications

Items

Specifications

Remarks[Axis configuration]① Head rotating axis: 2 directions (forward / reverse)② Head sliding axis: Extension pipe movable in the radial direction③ Head angle changing axis: Movable angle at which the tool performs according to the
S/C shape④ Tool rotating axis: Tilts in the direction of the welding line so that the tool applies to theentire bead.
⑤ Tool angle changing axis: Rotates the tool vertically⑥ Tool axial direction changing axis: Rotates the tool in the axial direction

Remarks①Head rotating axis
②Head sliding axis
Clampingmechanism③Head angle changing axis

Configurationof apparatus

Guide roller
Camera(for bird’seye view)

Configurationof apparatus
Camera (Forsurfaceobservation)

Grinder tool (air driven)
Cup type wire buff

Basicfunctions

Clamping mechanism(6 locations)⑥Tool axial directionchanging axis

[Axis configuration]① Grinder swivel axis: Swings in the rotational direction of the axis.
② Repeated forward / backward fine movement axis: Automatic forward /backward fine movement in the axial direction③ Grinder swing axis: Swings in the radial direction.
④ Grinder forward / backward movement axis: Moves in the radial direction.
⑤ Grinder vertical movement axis: Moves vertically.
⑥ Unit swivel axis: Rotates in the circumferential direction.

(1) It removes the loose rust present on the S/C surface, fromwhich the coating has been peeled off, before theinstallation of extension pipe.
(2) The apparatus is lowered down to a predetermined
location with a guide roller supporting the inner surfaceof the pipe and is fixed by means of the clamping
mechanism.
(3) The head position can be adjusted with respect to the S/C
surface near the extension pipe installation location bymeans of the apparatus axis.
(4) Using the grinder forward / backward movement axis, thegrinder vertical movement axis and the unit swivel axis,
the cup type wire buff is pressed against the surface tobe processed and loose rust is removed.
(5) The inclination can be adjusted using the grinder swivel
axis and the swing of the grinder swing axis to make thebuff touch the S/C surface evenly.
(6) The S/C surface that is within the scope of treatment, canbe observed using cameras and abnormal sounds canbe checked with directional microphones.

Basicfunctions④Tool rotating axis

⑤Tool angle changing axis

Head(buff / grinder)(1) Slag removal and polishing with wheel type buff during
and after welding*(2) Bead formation and grinding with a grinder (grindingstone) for the parts rejected in VT*(3) Chucking: The apparatus is inserted into the innersurface of the extension pipe with a guide roller andthen fixed with the clamping mechanism.
(4) Apparatus axis: The position of the head can be
adjusted using the apparatus axis so that it comes incontact with the welded portion.
(5) Control: The position aimed for can be adjusted
manually.
The head can be pressed with a constantforce by the air cylinder.
(6) Monitoring: Camera (1 or more), directional
microphones ** (1 or more)*: The head is replaced
depending on the use of
the apparatus such as forslag removal andpolishing or beadformation and grinding.

**: This functionality wasadded as a decisionindex for abnormal noise
detection, execution
management, etc.

©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼ STEP1 Details and results of element tests◼ Specifications of S/C joint welding apparatus
Item

Specifications

Remarks[Axis configuration]① Torch swivel axis: 2 directions (forward / reverse)② Torch vertical stage: Movable in vertical direction③ Torch forward / backward stage: Movable in the radial
MAG wire feeder
direction of the extension pipe
④ Torch inclination angle: Movable at the angle where theInserted guide frame
torch points to

Guide roller

Cross roller① Torch swivel axis

Gear

Gear M2[Purpose] To confirm the following items using a manual welding test on a simple-shaped simulated test specimen made offlat plate.
・ Optimal welding material
・ Welding conditions (current, voltage, welding speed, welding direction, torch angle (advancing angle, receding angle),
stacking pattern)・ Confirmation of the extent of polishing between passes (confirmation of the extent of slag removal through beadtreatment using buff)
・Confirmation of the extent of welding pre-treatment on S/C surface (confirmation of the condition of weldable surface(extent of rusting)).
Right[Test details]
・Method of execution: MAG manual welding Fillet welding
・Welding pre-treatment: Manual wire buff

② Torch vertical stage
Servo stage

Configurationof apparatus③ Torch forward /backward stage

Welding
torch
portionBasicfunctions◼

Weight: about 250 kgf(1) Welding method: MAG(2) Control: Teaching: Wire touch, up to 30 points
Welding speed / torch angle: Can be changed between
teaching points(3) Chucking: Fixed to the inner surface of the extension pipe with theclamp mechanism.
(4) Monitoring: Cameras (2 or more)
directional microphones* (1 or more)

ManualStep 1
Confirmation of
welding
conditions *(flat plate)

Step 2
Confirmationof welding
conditions *(cylinder)

Thickness

Material

Simulated S/C

Flat plate

19 mm

SM490

Reflect the test results
appropriately in the design*: This functionality was added
as a decision index forabnormal noise detection,
execution management, etc.

Unit function tests (STEP 3)
Automatic welding using the S/C joint welding
apparatus prototype
Part 2
Part 1
Confirming the functions
Adjusting the weldingof the prototype,conditions obtained inverifying the integrity of
the welding element
the welded portion
tests (preliminary tests)

Adjusting the welding
conditions obtained in thewelding element tests(preliminary tests), on the
prototype

Welding confirmation tests
using a combination of
prototype apparatus

S/C joint welding apparatus,
Weld bead treatment apparatus
Detailed design and prototype fabrication work of S/C joint
welding apparatus
Detailed design and prototype fabrication work of weld beadtreatment apparatus

12 mm

SM490

Crest

Manualwelding

Full-scale test

* Welding conditions: Welding material, current, voltage, welding speed, welding direction, torch
angle, stacking pattern, welding pre-treatment status, torch aiming location, wire
protruding length

TroughManual welding

0 mm
Left

<Distance from the center of S/C to center of extension pipe: 1500 mm*>

Distance from the center of S/C 700 mm
Distance from the center of S/C 1500 mm

Image of extension pipe installation at
1500 mm position<Image of the test specimen>[Test results]<Image of test specimen>

TroughItems

Criteria

Results

VT

There shall be no cracks
The predetermined throat thickness (10mm ormore) should be met.

Absence of cracks
The predetermined values were ensured using crosssectional macro.

Checking the shape of the penetration

There were gaps of 1mm or more at a few locations.
(It is not a problem as DT can be performed even if thegaps are partially eliminated.)DT
Simple automatic
Simple automatic welding when S/C is fully
weldingfilled with water
Confirm the impact ofStep 2.5
presence of water on
Confirmation of
the other side
welding
Confirm the impact ofconditions *water cooling and crack(flat plate)sensitivity

Flat plate

Gap・ The actual S/C inclination is simulated using the S/C angle simulation platform(flat plate) .
The extension pipe is simulated in all the 4 directions (crest, trough, left, right) of
the flat plate.
・The estimated distance from the center of S/C in the actual equipment: 700 mm,
1500 mmCrest

Test flow

Welding element tests (preliminary tests)
ManualShape

<Distance from the center of S/C to center of extension pipe: 700 mm*>
* : Maximum and minimum distances
for the selected positions
Image of extension pipe installation
at 700 mm position

CameraMAG torch

Test specimen

Simulated extension pipe

④ Torch inclination axis

No.53

(Reference confirmation)
cross-sectional macro[Results obtained from STEP 1 tests]◼ The following welding conditions were confirmed by manually welding the simple-shaped simulated test specimen.
• Method of welding: As volume inspection is not required and as there will only be the final level VT, MAG welding wasselected and it was checked whether or not welding is possible.
• Welding Material: Flux cored wire generates a large amount of slag and it cannot be removed completely with a buff, so solid
wire was selected.
• Basic welding conditions: Set the following general conditions and confirm that there is no problem.
Current: nearly 250A，Voltage: about 30V，Welding speed, Welding direction: about 20 ~ 30 cm/min (up, down)
Torch angle: 25° ~ 65° (1500 mm)，30° ~ 50° (700 mm)• Stacking pattern: Although the design throat thickness of 10 mm was satisfied with 3 layers and 6 passes, it was decided towork with 3 layers and 8 passes in order to allow some margin.
• Extent of polishing between passes by buff: Compare wheel type and cup type buffs.
As the anticipated welding location is in a confined space, a wheel type buff was selected considering the buff interference
while polishing the bead.
• Extent of welding pre-treatment on S/C surface: It was confirmed that there is no problem with direct buffing of the blackskinny (rust) surface of S/C simulated material.

©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼

STEP2 Details and results of element tests[Purpose] To confirm and verify the following items by manual welding test on actual equipment-shaped
simulated test specimen based on the conditions of STEP1.
・Welding conditions
・ Confirmation of the extent of polishing between passes (confirmation of the extent of slag
removal through bead treatment using buff)
・Confirmation of the extent of welding pre-treatment on S/C surface (confirmation of the conditionof weldable surface (extent of rusting)).
Right[Test details] ・Method of execution: MAG manual welding Fillet welding
・Welding pre-treatment: Manual wire buff [Wheel type]・ Number of passes: 3 layers 8 passes
Test specimen

Shape

Thickness

Material

Simulated S/C

Saddle type

19 mm

SB450

Simulated extension pipe

Semi-cylindrical15.9 mm

SM490

Manual welding

0 mm

There shall be no cracks.

DT(Reference
confirmation)
Cross-sectional
macro

There were gaps of 2mm or less at a few
locations.
Checking the shape of the penetration(It is not a problem as DT can be
performed even if portions equivalent to
the gaps are eliminated.

Left

R4450mm(Actual-equipment
simulated)

Example of crest side

[Results obtained from STEP 2 tests]◼ STEP2.5 Details and results of element tests＜Part 1＞

[Purpose] To confirm and verify the integrity of the welded part through a simple automatic welding test on a simpleshaped simulated test specimen based on the conditions obtained in STEP1 and STEP2.
[Test details]
Right
・Method of execution: MAG simple automatic welding
Fillet welding
・Welding pre-treatment: Manual wire buff [Wheel type]
Manual・Number of passes: 3 layers 8 passes
Manual welding
Troughwelding
Crest
Simulated S/C

ShapeThickness

Material

Flat plate

19 mm

SM490

Simulated extension pipe Flat plate

12 mm

SM490

Gap
0 mm

・ The actual S/C inclination is simulated using the S/C angle
simulation platform (flat plate).
The extension pipe of the platform (flat plate) is simulated in all
the 4 directions (crest, trough, left, right).
・The estimated distance from the center of S/C in the actual
equipment : 700 mm, 1500 mm

Results

There shall be no cracks.

Absence of cracks

DT

The predetermined throat thickness(10 mm or more) and leg length (17mm or more) should be met.

The predetermined values wereensured using cross-sectional macro.

(Reference
confirmation)
Cross-sectional
macro

Checking the shape of penetration

No weld penetration defects

It was confirmed that a simple-shaped simulated test specimen
can be welded by simple automatic welding under the conditionsof STEP1 and STEP2.
◼ It was projected that the actual equipment-shaped simulated test
specimen can be welded using automatic welding.
The welding conditions for the unit function tests using a STEP 3
prototype were derived.
→ It was determined that the unit function tests can be performed
using the STEP3 prototype.

Cross-sectional macro results(E.g.) 1500 mm position (trough)＜Part 2＞◼ It was confirmed that an actual equipment-shaped simulated test specimen can be manually welded using theconditions of STEP1.
〇1500 mm welding conditions
Current: Fixed to 270A ，Welding speed: 17 ~ 26 cm/min (including upwards and downwards), Torch angle:
25° ~ 60°
〇700 mm welding conditions
Current: Fixed to 270A ，Welding speed: 17 ~ 28cm/min (including upwards and downwards), Torch angle:
20° ~ 45°

Test specimen

Criteria

VT◼

Absence of cracks

The predetermined throat thickness (10The predetermined values were ensured
mm or more) and leg length (17 mm orusing cross-sectional macro.
more) should be met.

Items

[Results obtained from STEP2.5 (Part 1) tests]

・The actual shape of S/C is simulated and half-split pipes are simulated in all the four directions(crest, trough, left, right)
・The estimated distance from the center of S/C in the actual equipment: 700 mm, 1500 mm[Test results]
Items
Decision criteria
Results
VT[Test results]

Gap
Crest

No.54

◼ STEP2.5 Details and results of element tests (Continued...)Left[Purpose] To confirm the gap tolerance limit (The maximum gap limit with which S/C and extension
pipe can be welded in 1 pass).
[Test details]
・Method of execution: MAG simple automatic welding
Fillet welding
・Welding pre-treatment: Manual wire buff [Wheel type]
Simulated extension pipe・Number of passes: 1 pass
Test specimen

Shape Thickness

Material

Simulated S/C

Flat plate

19 mm

SM490

Simulated extension
pipeFlat plate

12 mm

SM490

Gap

Simulated S/CRefer tothe figure

・With a preexisting gap, an actual S/C inclination is simulated using the S/C
Confirmation of the gap
angle simulation platform (flat plate) and the extension pipe is simulated in all
tolerance limit between S/C andthe four directions (crest, trough, left, right) of the flat plate.
extension pipe
・The maximum size of the gap with which the S/C and extension pipe can bewelded is verified.
・The estimated distance from the center of S/C in the actual : 700 mm, 1500 mm[Results obtained from STEP2.5 (Part 2) tests]◼ It was confirmed that the gap tolerance limit value was 5 mm.
→ The obtained value is provided as a feedback as the allowable gap tolerance value for the positioningof S/C surface and extension pipe and is reflected in designs related to positioning accuracy.

Distance from the center of S/C 700 mm
Distance from the center of S/C 1500 mm©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C

ShapeThickness

Material

Gap

Pcm(Trough side)

Flat plate

17 mm

0.272*3

SB450
2 mm
*2

Simulated extension pipe Flat plate

12 mm

SM490

－

Water
temperature

Surfacethermocouple(Ch. 4 ~ 6)

Back surface
thermocouple(Ch. 1 ~ 3)・Water temperature: 12 ℃*4・Conditions such as current, welding speed: Conditions confirmed in the STEP2.5 element tests
・Filled with water (3 cases), no water (1 case)・Actual S/C inclination is simulated using the S/C angle simulation platform (flat plate), and the flat plate is put up
and welding is carried out. (Implemented by focusing on cases with conservative welding conditions)*1: Single pass is not expected to have a reheating effect compared to multi-layer filling, and it becomes hard andeasily cracks at low temperature.
*2: Considering stress concentration at the root: JIS Z 3158 Y-groove weld cracking test method*3: Use a plate (Pcm: 0.272) that covers the pcm (weld crack susceptibility composition) of actual S/C mill sheets
in 1F – 1/3 , which are likely to get filled with water.
*4: Use the lowest value from among the actual measurements (Jan 1, 2019 ~ May 8, 2019) at the 1F – 1~3 sites*5: In the downwards direction, the welding speed is faster than other welding directions and heat input is low,also, it is difficult for heat to enter the base material due to dripping from the pool.
*6: The slope is larger when compared with 700 mm, and the effect of the molten pool dripping during downwardwelding is large.
Line where hardness
is measured
Welded portion

Welded portion

Dendrite structure

No.55

Heat impacted
portionBase material
portionBainite structure

Ferrite / Pearlite
structure

Dendrite structure

Bainite structure

Ferrite / Pearlite
structure

Dendrite structure

Bainite structure

Ferrite / Pearlite
structure

Dendrite structure

Bainite structure

Ferrite / Pearlite
structure

No water[Hardnessmeasurement]
Filled with water(Specimen 1)[Cross-sectional macro][Test results]
Filled with water(Specimen 1)

Filled withwater
(Specimen 3)

Filled with water(Specimen 2)

Welded metal
portionHeat
impacted
portion・There is no difference inthe structure in all theregions
・The microstructures in
the heat impacted regionof the specimen full ofwater were bainite
structures and weresame as those in thespecimen with no water.
It does not become
martensitic, which is
generally seen during
quenching, and theimpact of water cooling islow.
Measuring
position+ sideExtension pipe

Welded metal
portionHeat impacted
Hardness
portionMeasuring
Base material
measuring position
position
portion- side・Although there is slight difference in hardness when full of water, the difference is not
significant.
・It is believed that the difference in the tendency of specimen 1 (filled with water), andspecimen 2 (filled with water) & specimen 3 (filled with water) is due to the difference inthe penetration shape.
Welded metal Heat impacted Base material(It is presumed that the variations in execution and the margin of error in apparatus
portionportionportioninstallation have impacted the weld penetration shape.)
Hardness measuring line
Welded metal Heat impacted Base material
portionportionportionNo weld penetration defects
No harmful defects such as cracks

Welded portion

Filled with water(Specimen 3)

No crack indicating pattern
Welded portion

Filled with water(Specimen 2)

No weld penetration defects
No harmful defects such as cracks

Welded portion

No crack indicating pattern

No water

Welded portion

Filled with water(Specimen 3)

No weld penetration defects
No harmful defects such as cracks

Welded portion◼
◼

Welded portion

No waterNo weld penetration defects
No harmful defects such as cracks

Welded metal Heat impacted Base material
portionportionportionWelded metal Heat impacted Base material
portionportionportionNo weld penetration defects

No weld penetration defects

Cross-sectional macro(specimen 1)

Cross-sectional macro(specimen 2)[Results obtained from welding impact confirmation test with water on the other side]◼

No crack indicating pattern

Hardness Hv

Simulated S/C

Welded metal
portionBase material
portionFilled withwater
(Specimen 2)

Hardness Hv

Test specimen[Cross-sectional
micro]
Filled with
(Crest side)
Constraining plates water(Specimen 1)

Hardness Hv[Purpose]To confirm the impact of completely water filled state of S/C, due to the welding of extension pipe
under STEP 2.5 (without water) conditions. As preheating is extremely difficult under on-site
conditions such as high dose, confined spaces and remote operations, the goal is to confirm thewelding conditions that can be executed without preheating.
Simulated[Test details]
extension pipe
・Method of execution: MAG simple automatic welding
Coolant
circulating
Fillet welding
pump
Simulated
・Welding pre-treatment: Manual wire buff
S/C・Number of passes: 1 pass *1

Hardness Hv◼ Details and results of welding impact confirmation test with water on the other side◼

When the specimen was full of water, under the welding conditions of STEP 2.5 tests (no water state) it was confirmed that there wereno cracks or weld penetration defects in the welded portion.
Slight difference in hardness was seen during the hardness test with the specimen full of water, but the difference was not significant.
The microstructures in the heat impacted region of the specimen full of water were bainite structures and were same as those in thespecimen with no water. It is presumed that it does not become martensitic, which is generally seen during quenching, the impact ofwater cooling is low, and low temperature cracking does not occur when the specimen is full of water.
→ It was projected that welding is possible when S/C is filled with water under the same conditions as when there is no water in it.

No crack indicating pattern©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼ Details and results of STEP3 unit function tests (related to welding apparatus and bead processing apparatus)＜Part 1＞◼

[Purpose] To adjust the welding conditions obtained from the welding element test (preliminary test).
The welding conditions obtained from the preliminary tests conducted using simulated test specimens of actual
equipment-shaped extension pipe and the S/C, are adjusted to be used in the prototype of S/C joint welding
apparatus.
Test specimen
Shape
Thickness
Material
Gap[Test details]

No.56

Simulated S/C
Simulated extension
pipe・Method of execution: MAG automatic welding Fillet welding
S/C joint welding apparatus (developed product) is used.
・Welding pre-treatment: Manual wire buff [Wheel type]
・Number of passes: 3 layers 8 passes
・Actual equipment-shaped S/C is simulated.
Half-split pipes are simulated in all the four directions(crest, trough, left, right).
・ The estimated distance from the center of S/C in theactual equipment : 700 mm, 1500 mm
・ Internal radius of simulated S/C: 4450 mm (equivalent
to 1F-3)
・ Distance from the flooring of R/B 1st floor to S/C: Not
simulated(A test to confirm the distance equivalent to 1F-3 to be
conducted in the full-scale test)
・ Environment (brightness / temperature / humidity):
Not simulated
・ The welding conditions* are adjusted as needed.
*: Welding speed, torch angle, torch aimed position,
conditional switching position (teaching position)[Test results]＜Distance from center of S/C: 1500 mm＞

19 mm

SM490

15.9 mm

SM490

5mm

Right

Automatic
welding using
S/C joint welding
apparatus

Crest

Left

R4450mm

Simulated
extension pipe
(upper part)
Bellows installation
location
Flange connection
Bolt fastening
For pressure resistance/ leakage test

Peepwindow for
observation
Simulated
extension pipe
(lower part)

Simulated S/C(Simulated actual
equipment)

Method of execution: GMAW automatic welding Fillet welding
Treatment of welded portion: Wire buff (Wheel type)
Number of passes: 3 layers 8 passes
TargetNumber Number Weldingofof
direction *1
layers passes

Welding
speed( cm / min)Torch angle(°) *2

Torch aimed
position *3
Aiming reference＜Distance from center of S/C: 700 mm＞

Cross-sectional macro

Crest

Right

Right

TroughTroughFusion defectWelding current: 270 A (fixed value), with pulse
Wire protrusion length: 15 mm
Welding speed [Refer to table on the left]: 20 cm/min ～30 cm/min
Torch angle [Refer to table on the left]: 45°～60°
Torch aimed position: Refer to image below*1: Welding is repeated in forward and reverse direction foreach pass.
*2: Torch angle indicates the angle between the welding
aimed position of the welding torch and the horizontal
line.
Simulated extension pipe Welding torch＜Test specimen＞

Cross-sectional macro

Crest

Saddle typeSemi-cylindrical

Cross-sectional macro: Although fusion defects due to weld penetration shape were noticed in the crosssectional monitoring in the four directions, since the DT criteria is met even if the said parts are excluded,
there is no problem.
<For 1500 mm> ① Fusion defects were seen on the left side (270°) of the 6th pass.
• Probable cause
It has occurred while welding in the downward direction. It is presumed that, while welding in the
downward direction, the molten pool has dripped and advanced in the welding direction ahead of thearc, which increased the distance from the surface of the molten metal to the base metal, because ofwhich sufficient heat was not transferred to the base metal, resulting in fusion defects.
• Measures : Not required(Fusion defects can be eliminated by further increasing the welding speed during downward welding,
reducing the amount of welding, and reducing the dripping of the molten pool. However, no measures
are considered necessary as the DT criteria is satisfied even if the said parts are excluded.)＜For 700 mm＞ ① Fusion defects were seen on the crest side (0°) of the 6th pass.
• Probable cause
It has occurred at the location where welding was started. It is presumed that at the location where MAG
welding was started, the arc was not stable and heat concentration became difficult causing fusion
defects. In addition, it is presumed that fusion defects occurred as the arc scattered outside the shielding
gas range.
• Measures : Not required (Same as for 1500 mm)◼ Welding conditions obtained in STEP3 (Part 1) (1500 mm position)

Downwards
Upwards
Downwards
Upwards
Downwards
Upwards
Downwards
Upwards

Simulated S/C

Torch angle
Horizontal line

*3: Torch aimed position indicates the deviation from theaiming reference in the X direction.

Aiming reference of N pass (1 ~ 8)(bead toe part)

Deviation in X direction

Left

Fusion defect
Left

Text in red indicates the changes from STEP2.5 conditions.

◼ VT: There were no harmful defects such as cracks or undercuts, overlaps, craters, slag
entanglements, pits in the final layer.
◼ DT: The conditions such as “throat thickness of 10 mm or more, leg length of 17 mm ormore” were satisfied for the test specimens in all four directions.

[Results obtained from STEP3 (part 1) tests]
As a result of applying the STEP2.5 conditions, the spread of the bead was confirmed.
Therefore, with the purpose of improving the stability and reproducibility of the bead shape,
STEP3 (part 1) was implemented by adding “torch angle” and partially modifying the “torch
aimed position” in STEP2.5.
©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼ List of STEP3 (part 2) test results＜Part 2＞
[Purpose] To confirm the functionality of the apparatus and verify the soundness of the welded portion.
・ The functionality of the apparatus is confirmed and the required joint performance is verified through a series ofoperations from apparatus installation / removal ~ welding work ~ up to bead treatment under conditions similar
to the actual equipment by combining the prototypes of S/C joint welding apparatus and weld bead treatment
apparatus, and it is reflected in the full-scale test procedure.
・The issues with the apparatus functionality are confirmed and the assumed risks are evaluated, and the issues
in the apparatus for full-scale test are identified (to be corrected before the start of the test to the extent
possible).
Shape
Thickness
Material
Gap
Simulated S/C

Saddle type

19 mm

SM490

Distance from thecenter of S/C

Cross-sectional macro

Blow hole *2

Crest*1 Overlap

Right

Trough

*1 Overlap

Fusion defect *2

Left

Joint tensile
test

Crest
Right

Tensile strengthof base metal(N/mm2)

Width of test
ThroatTensile loadpiece (mm) thickness (mm)(kN)

Tensile strength Efficiency of(N/mm2)the joint

Test pieceafter
pulling

1500
ｍｍ

5 ｍｍ

VT

PT

DT

0°

〇

〇

〇

Blow hole

90°

×*1

〇

〇

No defects

180°

×*1

〇

〇

No defects

270°

〇

〇

〇

0°

〇

〇

〇

No defects

700
ｍｍ

5 ｍｍ

〇: Yes, ×: No
Joint
tensile
test

No.57

Pressure
resistancetest

Leakage
test

－

－

－

※2 〇

〇

〇

－

－

－

〇

－

－

※2

Fusion defects ※2

90°

〇

〇

〇

Fusion defects

180°

〇

〇

〇

No defects

270°

〇

〇

〇

fusion defects

※2

0°

〇

〇

〇

Blow hole

〇

〇

〇

※2

90°

No defects

180°

〇

〇

〇

No defects

270°

〇

〇

〇

No defects

0°

〇

〇

〇

90°

〇

〇

〇

No defects

180°

〇

〇

〇

No defects

270°

〇

〇

〇

No defects

0 mm

R4450mm
Simulated
actualequipment

Direction

Crosssectional
macro

0 mm

0 mm,

5 mm
Simulated extension pipe
Pipe19.4 mm
SM490[Test details]
・Method of execution: MAG automatic welding Fillet welding
S/C joint welding apparatus(developed product) is used.
・Treatment of welded portion: Wire buff (Wheel type)
Right
Weld bead treatment apparatus (developed product) is used.
・Number of passes: 3 layers 8 passes
・Simulated specimens of actual-equipment shaped S/C and pipe shaped extension pipe are
Automatic welding
created.
using S/C joint Trough
Crest・The estimated distance from the center of S/C in the actual equipment:700 mm, 1500 mm
welding apparatus
・Internal radius of simulated S/C: 4450 mm (Equivalent to 1F-3)
・Distance from the flooring of R/B 1st floor to S/C: Not simulated(A test to confirm the distance equivalent to 1F-3 to be conducted in the full-scale test)
Left
・ Environment (brightness / temperature / humidity): Not simulated
・The process of welding with S/C joint welding apparatus and then polishing the welded parts
with bead treatment apparatus, is repeated.

[Test results] <Example of the location where the distance from the center of S/C: 1500 mm, gap: 0mm>

Gap

(Decision results)※2*1: Presence of harmful defect (no cracks, undercuts, craters, slag entanglements, pits) due to overlap at 0° and 180° on the 7th pass found during VT.
• Probable cause for overlap: It is presumed that the cause was that during the upward welding of the 1st, 3rd, 5th, and 7th passes in the clock-wise
direction, the torch cable must have come in contact with the extension pipe and bent, because of which the wire must have bent upwards during welding
and must have deviated from the aimed position during teaching.
• Measures: ・Improvement of cable management methods such as storing the torch cable inside the apparatus.
・Resetting the criteria for pass / fail of VT (E.g. Determined in combination with DT) (Leave it as an issue to be dealt by Engineering)*2: Although blow holes and fusion defects were seen in the cross-sectional macro, since the DT criteria is met even if the said parts are excluded, there is
no problem.
• Probable cause for blow hole: It has occurred at the location where welding was started. It is presumed that the arc was not stable at the location where
MAG welding was started, got scattered outside the shielding gas range resulting in the generation of blow hole.
• Measures: Not Required (Considering the characteristics of MAG, blow hole is presumed to have occurred due to the disorder of the arc at the location
where the welding was started. So, this can be solved by scraping the weld metal at the location where welding is started and starting the next pass fromanother location. However, as DT criteria is met even if the said parts are excluded, no measures are required.)
The causes and countermeasures
for fusion defects are the same as those for STEP (part 1) test.
＜Criteria＞◼
VT: There shall be no harmful defects such as cracks or undercuts, overlaps, craters, slag entanglements, pits in the final
layer.
◼
PT: Absence of cracks in the final layer◼
DT: “Throat thickness of 10 mm or more, leg length of 17 mm or more” should be satisfied based on the cross-sectional
Test piece
Extension pipe
macro for all four directions.
fixed block◼
Cross-sectional macro: The shape of the penetration should be checked through cross-sectional macro for all four
Weldeddirections.
portion◼
Pressure resistance test: Should withstand the test pressure of 110 kPa or more and should not get deformed excessively
for 10 minutes or more.
Test
piece
◼
Leakage test: The test pressure should be 90 kPa or more and the pressure drop after 60 minutes should be 5 kPa or less.
constraining◼
Joint tensile test *3: In addition to the strength of the welded joint, the joint efficiency of 0.35 should be satisfied.

jigTrough*3: The actual value of joint efficiency is calculated based on the load-displacement curve from the tensile test and actual throat thickness
measurement value: Joint efficiency η＝σTJ / σTB* 4 Throat thickness is the average value of the measured
Here, σTJ: Tensile strength of joint = breaking load in tensile test / throat cross section (throat thickness*4 x width of test piece), σTB: Tensile strength of base metal = Tensile strength of base metal of test piece (mill sheet)values of two cross sections of the test specimen.
Left

Image on joint tensile test

©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C◼ Following are the welding conditions applied in the full-scale test (distance from the center of
S/C: 1500 mm) based on the STEP3 (part 1) test results.
Method of execution: GMAW automatic welding Fillet welding
Treatment of welded portion: Wire buff (Wheel type)
Number of passes: 3 layers 8 passes
TargetNumber Number Weldingofof
direction *1
layers passes

Welding
speed(cm / min)Torch angle(°) *2

Torch aimed
position *3

Aimingreference

Welding current: 270 A (fixed value), with pulse
Wire protrusion length: 15 mm
Welding speed [Refer to table on the left]: 20 cm/min～30 cm/min
Torch angle [Refer to table on the left]: 45°～60°
Torch aimed position: Refer to image below

Item

Specifications

Seal case

Simulated extension pipe

Pressure port

Right

Pressure

Isolationmechanism
Sealing position 4

Temporary sealing
apparatus

Sealing position 3

Tube seal

Configurationof apparatus

Welding torch

Insertion guide

Extension pipe
(lower end)

Simulated S/C

Downwards
Upwards
Downwards
Upwards
Downwards
Upwards
Downwards
Upwards

Remarks
Canister(Seal diameter)*1: Welding is repeated in forward and reverse direction for each pass.
*2: Torch angle indicates the angle between the welding aimed
position of the welding torch and the horizontal line

Crest

Torch angle

Sealing position 2
Sealing position 1

While in service, the pressure
inside the extension pipe ismonitored to check for leakoccurrence tendency, and if aleak is suspected, the water
intake operation is stopped, theintake facilities are recovered
and then this apparatus is used
for inspecting the extension pipe
for leakage.

(The leak points are identified bychanging the position of the apparatus)<Outline image of local leak test in actual equipment>

Horizontal line
*3: Torch aimed position indicates the deviation from theaiming reference in the X direction.
Basicfunctions

Aiming reference of N pass (1 ~ 8)(bead toe part)TroughNo.583) Development and verification of temporary sealing apparatus◼ Specifications of temporary sealing apparatus

As level 2 inspection inside the extension pipe (intake part of S/C),
the lower end of the extension pipe is closed with the temporary
sealing apparatus and a local leak test (including the temporarystorage container) of the S/C intake part is performed. If a leak is
confirmed, leak location is identified by moving this apparatus step bystep and narrowing down the pressurization range.
(Diameter inside the pipe)

Left

Upwards
Downwards
Upwards
Downwards
Upwards
Downwards
Upwards
Downwards(Seal diameter)

Deviation in X direction◼ Element test of temporary sealing apparatus (details and results)(Weld bead)(Minimum pass-through diameter)[Purpose]
To verify the following items pertaining to the temporary sealing apparatus used for the leaktest in this element test.
Weld bead(a) Dropping property of temporary sealing apparatus(Height 2.5 mm)(b) Sealing property under normal installation conditions(Reference test) Sealing property during occurrence of mispositioning

Text in red indicates the changes from STEP3 (part 1) conditions.

◼ Teaching position: Set a total of 24 teaching points (TP) for every 15°.
･Manually remote control
the welding torch using
the camera screen on thewelding device to match
the welding aimingreference.
･Record the matching
points on the device asteaching points.

Camera image during teaching[Results obtained from STEP3 (part 2) tests]･The welding conditions for full-scale tests were set･ As a result of applying the STEP3 (part 1)
conditions, the bead easily tends to become convex
if the torch angle is set too high during upward /downward (right / left) movement under the 1500
mm condition. So, STEP3 (part 2) conditions wereformed by changing the “torch angle” to be based on
45°, and partially changing the “torch aiming
position” in STEP3 (part 1).

Wire(a) Test for confirming the dropping property of temporary sealing apparatus[Test details]✓

Test method: Temporary sealing apparatus is dropped down by ahoist and is made to pass through the simulated welding
reinforcement level difference in the joint welded part of the simulated
extension pipe.
Test parameter: piping material (SUS steel, carbon steel with coating),
presence of surface condensation, inclination of extension pipe (0, 1°)
Testing conditions: Testing temperature -> room temperature
Simulated extension pipe
Criteria: Able to move up and down smoothly inside the simulated(SUS pipe, dry)extension pipe by only operating the hoist (without manual assistance).

✓✓✓◼ Details and results of STEP3 unit function tests (related to bead treatment apparatus)◼ Weld bead formation using grinder on the parts rejected in VT
・ Welding beads can be ground with a grinder, but the method for adjusting the shape of the weld beads cannot be established.
＜Probable cause＞
・ The thickness of the grindstone is as thin as about 3
mm and it comes in contact with the weld bead onlyin the form of a line, thus making the adjustment of
weld bead shape difficult.
＜Measures＞
・ Change to a grindstone shape so that the entire
plane can come in contact with the weld bead (leave
it as an issue to be dealt by Engineering).

Shackle[Test results]
No.
1
2
3
4
5
6
7
8

Test cases

ResultSUS pipe，absence of condensation
SUS pipe，presence of condensation
Inclination of
Carbon steel pipe (presence of coating)，
extension pipeabsence of condensation0°
Carbon steel pipe (presence of coating)，
presence of condensation
SUS pipe， absence of condensation
SUS pipe， presence of condensation
Inclination of
Carbon steel pipe (presence of coating) ， extension pipe1°absence of condensation
Carbon steel pipe (presence of coating) ，presence of condensation

Good
Good

Pressure

Dropped down using
hoist
Simulated reinforcement level
difference(H=2.5 mm, W=25 mm)

Temporary sealing
apparatus

Good
Good
Good
Good
Good

[Results obtained from this test]
Each of the factors (SUS / carbon steel, with orwithout coating, with or without condensation,
inclination of extension pipe of about 1°) have very
low impact on the dropping property of the apparatus.

Good©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C

No.59(b) Test for confirming sealing property under normal installation conditions(Reference test) Test for confirming sealing property when there is rotational deviation[Test details]✓ Testing methodi)
The temporary sealing apparatus is dropped down using a hoist.
ii) The tube seal of the temporary sealing apparatus is pressurized to 0.10 to 0.15 MPaG. After pressurizing thetube seal, the valve (V4) on the pressurizing line is closed.
iii) The inside of the extension pipe below the temporary sealing apparatus is depressurized to -10 kPaG.
iv) After closing the depressurizing line valve (V1), the pressure and temperature history is recorded for 60
minutes.
✓ Test parameter: piping material (SUS steel, carbon steel with coating), presence of surface condensation✓ Testing conditions: Test medium ->air, test temperature -> room temperature✓ Criteria a. Structural stability: There shall be no significant mispositioning of temporary sealing apparatus during
depressurizationb. Sealing property: Leakage rate shall be 0.5 vol%/h or less (Note 1)[Test details]✓ Testing methodi) The temporary sealing apparatus is dropped down by a hoist, it is held at an angle of about 15° with respect to thehorizontal level, and the inclination of the temporary sealing apparatus from the horizontal level is measured by adigital spirit level.
ii) The state said in i) is maintained and the tube seal of the temporary sealing apparatus is pressurized to 0.10 to 0.15
MPaG. After pressurizing the tube seal, the valve (V4) of the pressurizing line is closed and the inclination of thetemporary sealing apparatus is measured again.
iii) The inside of the extension pipe below the temporary sealing apparatus is depressurized to -10 kPaG.
iv) After closing the depressurizing line valve (V1), the pressure and temperature history is recorded for 60 minutes.
✓ Test parameter: ･Pipe material (SUS steel, carbon steel with coating), presence of surface condensation✓ Testing conditions: Test medium ->air, test temperature -> room temperature✓ Criteria (for reference) a. Structural stability: Confirmation for occurrence of significant mispositioning of temporary
sealing apparatus during depressurization.
b. Sealing property: Calculation of leakage rate (Refer to test (b) Note 1 for calculation method)(Note 1) Leakage rate is calculated using the following formula by the method of "Calculation of leakage rate byatmospheric pressure comparison method" explained in JIS Z 4820 "Glove box sealing testing method“.
During the test, the temperature and atmospheric pressure (1.013 x 105Pa) are assumed to be constant.
Leakage amount: Q = Ve x (ΔP/1.013 x 105) x (3600/t)
Leakage rate: q＝ (Q/Ve) x 100 [vol％/ｈ]

Simulated extension
pipe (carbon steel
pipe, dry)[mL/h]

Simulated extension
pipe (carbon steel
pipe, dry)Temporary sealing
apparatus

Protrusion of tube
seal bent partPressure
plate

Tube seal

Here, Q : Leakage amount (mL/ｈ)
Ve: Equivalent internal capacity (=1.147 x 105 mL)
ΔP: Pressure change at the start and end of the test (Pa)t: Inspection time (sec)q: Leakage rate (vol%/ｈ)
T1: Temperature at the start of the test (℃)
T2: Temperature at the end of the test (℃)[Test results]
Test cases
Pipe material, Presence orabsence of condensation

SUS pipe, absence of condensation About 14.7°

Temporary sealing
apparatus

SUS pipe, presence of condensation About 14.8°

Simulated extension pipe
(SUS pipe, condensation)[Test results]

Inclinationof theapparatus

Leakage test status

Test cases
Pipe material, presence of Inclinationof theapparatus
condensation
SUS pipe, absence of condensation
SUS pipe, presence of condensation About
Carbon steel pipe (with coating), absence of 0°
condensation
Carbon steel pipe (with coating), presenceof condensationa.
Result

P1 at test
start time

P2 at test
end time

Pressurechange at theend of the test

Pressure

T1 at test T2 at test change at thestart time start time end of the test

LeakageamountLeakage
rate

Good
Good
Good
Good

[Results obtained from this test]
In the sealing property confirmation test of the temporary sealing apparatus in its normal installation state(about 0°), there was no significant displacement of the temporary sealing apparatus in any of the cases
due to decompression inside the extension pipe, and the leakage rate was 0.5 vol%/h or lower.
It was confirmed that sufficient structural stability and sealing property can be exhibited.

b.
Result

Good
Good
Good
Good

a.
Result

P1 at test
start time

P2 at test
end time

Pressurechange at theend of the test

Pressure

T1 at test T2 at test change at thestart time start time end of the test

LeakageamountLeakagerateb.
Result

Good
Good

Good
Good

Carbon steel pipe (with coating),
absence of condensation

About 4.7°

Good

Good

Carbon steel pipe (with coating), presenceof condensation

About 2.4°

Good

Good

[Results obtained from this test]
When installed with a large rotational deviation, there was no significant
difference in leakage performance in SUS pipes when compared to the normal
installation state.
In carbon steel pipe with coating, when the tube seal is pressurized, the entire
temporary seal slides and rotates greatly in the vertical direction, making sealing
impossible.
→ For the actual equipment, it is desirable to take measures to prevent therotation of the apparatus in consideration of the installation state with rotational
deviation.
E.g.) Providing a rotation control mechanism in which the insertion guide in thetemporary sealing apparatus is extended.

Extended insertion guide[Summary of the development of element technology required for accessing andconnecting inside S/C]･ The specifications of each apparatus were clarified.
･ The satisfaction of passing criteria of element tests and unit function tests of each apparatus was
confirmed (tests are still in progress).
･ The issues and solution policies were clearly specified (shown in 7.(2)).
©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technology for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C
4) Schedule for the development of technology for establishment of S/C water intake part
: Designing andapparatus fabrication◼ Construction of S/C water intake structure
Items: Element tests

Second half of FY2018
１0

１１

１２

１

２

No.60

: Function tests (prototype)First half of FY2019
3

4

5

6

7

8

: Actual results: Full-scale test

Second half of FY2019
9

10

１１

１２

1

2

3

＜ Technology development for establishment-related apparatus ＞
1. Overall system design
Desk study*

2. S/C surface treatment apparatus*: It is determined during desk studies that theexisting technology can be applied. Element
tests, apparatus fabrication, anddemonstration will be done during theengineering stage.

Desk study*

3. Welding reinforcement removal apparatus
Desk study (Configuration of required marking details)

4. Marking apparatus
5. Positioning apparatus

Detailed designing, prototype fabrication

6. Gap measuring apparatus

Desk study, preparation for element tests

7. Among the welded part cleaning apparatus...
S/C surface polishing apparatus, weld bead treatment apparatus

Detailed designing, preparation forelement tests, prototype fabrication

8. S/C joint welding apparatus
9.

Other common devices
installation cart, etc.)

Detailed designing, prototype fabrication (Only desk study for S/C surface polishing apparatus)

Welding element test (preliminary test: confirmation of welding conditions, etc.)(base

plate,

Detailed designing simple apparatus fabrication＜Simple apparatus fabrication in the full-scale test PJ for 1/1 scale assembly test＞
Desk study

10. Guide ring removal apparatus
11. Apparatus for surface preparation / coating＜Full-scale test of establishment-related apparatus

Desk study*

Arrangement / fabrication (modification) of test facilities
Test specimen
is stored.

: Factory implementation＞
1/1 scale assembly test
(Confirmation of remote operability)① Confirmation of remote operability with apparatus No. 5 ~ 9 (Includes preparation)② Confirmation of integrity of welded portions (includes cleaning)©International Research Institute for Nuclear Decommissioning

(2) Development and verification of element technologies for accessing and connecting inside PCV② Development and verification of element technology required for accessing and connecting inside S/C
4) Schedule for the development of technology for establishment of S/C water intake part
: Designing andapparatus fabrication◼ Inspection / repair of S/C water intake structure

Items: Element tests

Second half of FY2018
１0

１１

１２

１

２

: Function tests (prototype)First half of FY2019
3

4

5

6

7

8

No.61
: Actual results: Full-scale test

Second half of FY2019
9

10

１１

１２

1

2

3

<Technology development for inspection / repair related apparatus>

1. Temporary sealing apparatus
Desk study*

2. Foaming solution supply system
Desk study*

3. Coating agent applying apparatus*: It is determined during desk studies
that the existing technology can beapplied. Element tests, apparatus
fabrication, and demonstration will bedone during the engineering stage.

Desk study*

4. Tracer gas feeder©International Research Institute for Nuclear DecommissioningNo.62

7． Overall summary(1) Level of achievement of initial target① D/W water intake part (Target TRL at completion: Level 4)② S/C water intake part

(Target TRL at completion: Level 4)(2) Issues and response policies① D/W water intake part② S/C water intake part©International Research Institute for Nuclear Decommissioning

(1) Level of achievement of initial target① D/W water intake part (Target TRL at completion: Level 4)
Criteria for determining goal
achievement

Element tests pertaining to the technology
for remotely operating the connection parts
should be completed at the factory and theacceptance criteria of the element tests
should be met. Or else, the issues to beresolved and the resolution policy should beclearly specified.

Completed items
Main issues

Element tests were conducted for thesuspension and installation of the pumpto the bottom of the D/W (pump pit),
connection of pipes (hose), and therecovery of the pump for pump
replacement through remote operations,and a feasible outlook was obtained.
The main issues are summarized below.
・Monitoring method during operations(Camera, lighting arrangement, etc.)
・Hose feeding and lashing method
・Method of fixing the pipe to the utility
stand・Mispositioning between pipes
・Cable treatment* for various
apparatus

No.63

Achieved TRL
level
(Self
evaluation)

4(*3)*: Has not reached the target TRL level©International Research Institute for Nuclear DecommissioningNo.64(1) Level of achievement of initial target② S/C water intake part (Target TRL at completion: Level 4)
Criteria for determining goal achievement

Element tests pertaining to the technology for remotely
operating the connection parts should be completed at thefactory and the acceptance criteria of the element tests
should be met. Or else, the issues to be resolved and theresolution policy should be clearly specified.

Completed items
Main issues

Achieved TRL level(Self evaluation)＜ Gap measuring apparatus＞
・The following passing criteria were met in theelement test using only the hand-held scanner,which is the main component of the gap
measuring apparatus.
(*: partially not achieved)- The margin of error between the gap value
measured using hand-held scanner and theactual measurement was ±1 mm or less.*(*Parts of S/C, extension pipe where data is
missing) : In the case of a rotary scan using amanual or rotary jig- It is possible to confirm the markings with the 3Dmodel obtained from the scan data.
- The margin of error between the throat thickness
value obtained by means of the 3D modelobtained from the scan data before and after
welding and the actual throat thickness measured
by means of cross-sectional macro-observation
was ± 1 mm or less* (* The values obtained fromthe model are more conservative than the actual
measurement, and hence the current process will
be continued.)

4(*3)

・The issues that must be resolved and the resolution
policies were identified.

<Positioning apparatus>
・The following passing criteria were met in the unit
function test of positioning apparatus.
- The gap with the extension pipe can be adjusted
to 5 mm or less. (Fine adjustments can be done
by visually checking the image from monitoring
tool camera mounted in 4 directions.)

4©International Research Institute for Nuclear DecommissioningNo.65(1) Level of achievement of initial target② S/C water intake part (Target TRL at completion: Level 4)
Criteria for determining goal achievement

Completed items
Main issues

Achieved TRL level(Self evaluation)

Element tests pertaining to the technology for remotely
operating the connection parts should be completed at thefactory and the acceptance criteria of the element tests
should be met. Or else, the issues to be resolved and theresolution policy should be clearly specified. (Continued...)＜S/C joint welding apparatus and bead treatment
apparatus＞
・The following passing criteria were met in a seriesof remotely operated unit function tests.
(*: Partially not achieved)- Final level VT: There were no harmful defects*
such as cracks or undercuts, overlaps, craters,slag entanglements, pits (*Presence of someoverlaps)- DT of welded parts: Using cross-sectional macro it
was confirmed that the predetermined throat
thickness of 10 mm or more, and leg length of 17mm or more was met.
- Pressure resistance test: Withstood the test
pressure of 110 kPa, and no excessive
deformations were seen.
- Leakage test: For the test pressure of 90 kPa, thepressure drop after 60 minutes was 5 kPa or less.
- Joint tensile test: Joint efficiency was 0.35 or more
＜Reference confirmation＞- Final level PT: Absence of cracks- Cross-sectional macro-observation: There weresome fusion defects and blow holes in the weld
penetration shape, but as the DT criteria is met
even if the said parts are excluded, there is no
problem.
・The issues that must be resolved and theresolution policies were identified.

4(*3)©International Research Institute for Nuclear DecommissioningNo.66(1) Level of achievement of initial target② S/C water intake part (Target TRL at completion: Level 4)
Criteria for determining goal achievement

Completed items
Main issues

Achieved TRL level(Self evaluation)

Element tests pertaining to the technology for remotely
inspecting access routes while in service at the time ofestablishment, should be completed at the factory andthe acceptance criteria of the element tests should be
met. Or else, the issues to be resolved and theresolution policy should be clearly specified.

＜Temporary sealing apparatus＞
・The following passing criteria were met in theelement test of temporary sealing apparatus.
- Dropping property of the apparatus: Can moveup and down smoothly inside the simulated
extension pipe by only operating the hoist(without manual assistance).
(When piping material: SUS, carbon steel withcoating, presence or absence of condensation,and inclination of extension pipe: 0° or 1°)- Structural stability and Sealing property:
There was no significant displacement of theapparatus when the apparatus was
decompressed in its normal installation state,
and leakage rate was 0.5 vol%/h or less.
(When piping material: SUS, carbon steel withcoating, presence or absence of condensation)- When the apparatus is inclined as during thereference tests, a part of it did not havestructural stability and sealing property.
(With SUS, it was possible. In the case ofcarbon steel with coating, presence or absenceof condensation it was not possible)
・The issues that must be resolved and theresolution policies were identified.

4©International Research Institute for Nuclear DecommissioningNo.67(1) Level of achievement of initial target② S/C water intake part (Target TRL at completion: Level 4)
Criteria for determining goal
achievement

Element tests pertaining to the technology
for remotely carrying out maintenance ofthe connection parts while in service at thetime of establishment, should be completed
at the factory and the acceptance criteria ofthe element tests should be met. Or else,the issues to be resolved and the resolution
policy should be clearly specified.

Completed items
Main issues＜ Bead treatment apparatus＞
・The following passing criteria weresatisfied in the following unit function
tests.
(*: Partially not achieved)- In the unit function test using beadtreatment apparatus, it was possible
to treat the weld bead at the base of
the extension pipe with a grinder'sgrindstone.
The method for adjusting the shapeof the weld beads could not beestablished. *・The issues that must be resolved
and the resolution policies wereidentified.

Achieved TRL
level
(Self
evaluation)

4(*3)©International Research Institute for Nuclear Decommissioning

(2) Issues and response policies① D/W water intake part
No.

1

2

3

4

5

Legends for response policies
No.68
A: Verification required in full-scale
B: Can be verified by element test in factory
C: Requires adjustment / resolution in the engineering for execution

Category

Issues and countermeasures

Response
policies

Work monitoring

It is difficult to check the operations related to installation of pipe connecting jig toutility stand, pump recovery operation from the basement, etc. with the camera
images.
Review camera and lighting arrangements, such as attaching a camera to the tip of
the work apparatus and checking the apparatus, to make the monitoring of eachwork easier.

C

Hose handling

When fixing the hose laid on the basement floor to the utility stand or when
installing the hose on the hose drum during pump recovery, the hose gets pulled
toward the basement floor by its own weight, making the connection of pipes andpump recovery difficult.
Consider an apparatus that sends the hose onto the grating or temporary lashingmethods.

C

Fixing of pipes

While fixing the pipe to the utility stand by inserting a nail into the groove on thestand side with a remote apparatus, it is difficult to confirm that the nail is inserted
all the way inside.
It is necessary to review the structure so that work can be done easily with aremote apparatus.

C

Fixing of pipes

While connecting the pipes, there was mispositioning between the pipes and hence
the pipes could not be connected with the connection jig.
Considering the application to the actual equipment, study the methods andprocedure for centering the pipes.

C

Cable treatment

As there is no apparatus that remotely assists the cables of various apparatus,
manual assistance was provided during this test.
As apparatus and cables are crowded in a confined environment, study a remotetreatment method. [Study in progress as part of the Further Increasing The Scale
Of Retrieval PJ]

B©International Research Institute for Nuclear Decommissioning

(2) Issues and response policies② S/C water intake part

Legends for response policies
No.69
A: Verification required in full-scale
B: Can be verified by element test in factory
C: Requires adjustment / resolution in the engineering for execution

No.

Category

Issues and countermeasures

Response policies

1-1

Gap measuringapparatus

Establishment of measures against loss of S/C surface scan data
→ Complete shape determination by collecting data of nearby positions to compensate forthe missing data.
(To be reflected in full-scale test)

A*

1-2

Gap measuringapparatus

Establishment of measures against loss of scan data of extension pipe lower end→・Complete the positions of missing range using the pre-scanned 3D model.
・Further expand the scanning conditions (mounting angle, position).
(To be reflected in full-scale test)A*

Gap measuringapparatus

Establishment of measures against loss of scan data due to impact of glossiness→・ Photographing should be avoided immediately after buffing, and shall be done a few
hours after the occurrence of loose rust.
・Instead of photographing from directly in front of the measurement point, it shall bedone from an angle.
(To be reflected in full-scale test)

A*

1-3

*: Verified during the Full-scale Test PJ©International Research Institute for Nuclear Decommissioning

(2) Issues and response policies② S/C water intake part

Legends for response policies
No.70
A: Verification required in full-scale
B: Can be verified by element test in factory
C: Requires adjustment / resolution in the engineering for execution

Classification

Issues and countermeasures

Response
policies

2-1

S/C joint welding
apparatus

Establishment of measures against overlap(During welding, the torch cable and the extension pipe come in contact with each other causing thewire tip to bend upwards, causing overlap due to deviation from the aimed position during teaching.)→・Improve the cable management method, such as by storing the torch cable inside the apparatus(improvement in current apparatus).
・Reset the criteria for pass / fail of VT (E.g. Decide in combination with DT)

C

2-2

S/C joint welding
apparatus

Establishment of repair welding methods for defective welds of each pass→・Set the criteria for deciding the necessity of repair.
・Study repairing methods, develop dedicated tools for execution (improvement in current
apparatus).

C

2-3

S/C joint welding
apparatus

Establishment of measures against condensation on the surface of welded parts→ Eliminate condensation by feeding dry air inside the extension pipe before welding and by injecting
shield gas in the S/C joint welding apparatus.

C

2-4

S/C joint welding
apparatus

Establishment of a method for recovering the stuck wire
→ With the wire stuck, pull up the S/C joint welding apparatus, cut and pull out the wire, and thenperform bead molding / repair welding of said parts (planned to be done partially by remote
operations).

C

2-5

S/C joint welding
apparatus

Currently, it is possible to get the results of VT of the welded part using the camera mounted on the
S/C joint welding apparatus, but the image quality should be further improved for a clearer judgment.
→・Change to a camera with auto-focus (improvement in current apparatus).
・Review and improve camera and lighting arrangement.

C

2-6

S/C joint welding
apparatus

Measures against fume scattering during welding→ During execution, install a closing lid on the top of the extension pipe + suction, etc.

C

2-7

S/C joint welding
apparatus

Measures to reduce radiation exposure of workers during carrying-in, raising, lowering and removal
operation of the apparatus→ Based on full-scale test results, consider reducing the number of workers and time allotted forengineering, and try to move from manual operations to remote operations further.

No.

*: Verified during the full-scale test PJ

A*, C©International Research Institute for Nuclear Decommissioning

(2) Issues and response policies② S/C water intake part

Legends for response policies
No.71
A: Verification required in full-scale
B: Can be verified by element test in factory
C: Requires adjustment / resolution in the engineering for execution

No.

Category

3-1

Weld bead treatment
apparatus

Establishment of methods for adjusting the shape of the weld bead using a grinder (grindstone) for the parts
rejected in VT (The thickness of the grindstone is as thin as about 3 mm and it comes in contact with the weld
beat only in the form of a line, thus making the adjustment of weld bead shape difficult.)→ Change to a grindstone shape such that the entire plane can come in contact with the weld bead
(improvement in current apparatus).

C

3-2

Weld bead treatment
apparatus

Establishment of welding defect elimination and bead formation methods for each pass・Study repairing methods, develop dedicated tools for execution (improvement in current apparatus).

C

3-3

Weld bead treatment
apparatus

Establishment of measures against dust scattering caused by bead treatment→ During execution, install a closing lid on the top of the extension pipe.

C

3-4

Weld bead treatment
apparatus

Measures to reduce radiation exposure of workers during carrying-in, raising, lowering and removal operation of
the apparatus→ Based on full-scale test results, consider reducing the number of workers and time allotted for engineering, andtry to move from manual operations to remote operations further.

4-1

Temporary sealing
apparatus

Prevention of apparatus rotation when the apparatus is installed with a rotational deviation.
→ Implementation of rotation control mechanism

C

5-1

On-site environment

Establishment of countermeasures (robustness) that can deal with unexpected circumstances resulting frominsufficient information on actual equipment→・Establish drying procedures for condensation environment (Same as No.3-3)
・ Add a level adjustment mechanism to the base plate to accommodate the inclination of the flooring of R/B 1 st
floor.
・Study decontamination / measures against exposure in contaminated areas. .

C

5-2

Apparatus excluded fromthe scope of development
under this PJ

Development and designing of apparatus excluded from the scope of development under this PJ→ Engineering shall develop and design based on the issues and development items put together for eachapparatus.

C

5-3

On-site survey

On-site survey required for promoting the development of apparatus excluded from the scope of development
under this PJ→ Develop and design apparatus taking into account specific interferences (especially interference removal
apparatus).

C

5-4

Mobile S/C water intake
cell

Development and designing of mobile S/C water intake cell
→ Share the trends of mobile cell technology development that is part of Further Increasing The Scale Of
Retrieval PJ.

B,CIssues and countermeasures*: Verified during the Full-scale Test PJ

Response policies

A*, C©International Research Institute for Nuclear Decommissioning

No.72©International Research Institute for Nuclear Decommissioning