Subsidy Project of Decommissioning, Contaminated Water, andTreated Water Management

Development of Investigation Technology for inside theReactor Pressure Vessel (RPV)(Upgrading of Processing Technology for the Top-Access
Investigation Method and Development of the Bottom
Access Investigation Method)
FY2022 Final Report
June 2023
International Research Institute for Nuclear Decommissioning (IRID)
All rights reserved.
©International Research Institute for Nuclear Decommissioning

No.1

Contents
1. Research background and objectives
2. Goals
3. Action items, their inter-relation and relation to other studies
4. Implementation schedule
5. Project organization chart
6. Implementation details(1) Upgrading of processing technology for the top-access investigation method• • • • • • • • • • • No.8
(2) Development of the bottom access investigation method- Unit 1: Development of drones for accessing the RPV interior • • • • • • • • No.39- Units 2 and 3: Development of telescopic equipment for accessing the RPVinterior • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • No.114©International Research Institute for Nuclear Decommissioning1. Research background and objectives

Top access investigation method

No.2[Purpose of investigating inside the reactor pressure
vessel (RPV)]
Acquisition of basic information about the RPV interior (distribution offuel debris, radiation dose, structure condition, etc.) in order to retrievefuel debris.

[Implementation details up to FY2021]
By FY2019, the applicability of top and side access investigation
methods had been studied with actual equipment.
Since FY2020, to address the remaining issues in the top-accessinvestigation method, alternative methods for opening reactor internals
to establish an access route to the shroud have been developed asprocessing technologies that would generate less secondary waste
inside the RPV than the conventional abrasive water jet (AWJ) method.
It is also important to continue developing methods that enable
investigation inside the RPV at earlier stages, since it is assumed thatthe top and side access investigation methods will require some time
before they can be applied on site. Therefore, starting in FY2020,
investigation plans for the bottom access investigation method havebeen formulated, and conceptual studies of bottom access andinvestigation equipment have been conducted. In this method,
investigation equipment is introduced into the primary containment
vessel (PCV) using the access route already constructed forinvestigation inside the PCV, and the equipment is introduced into the
RPV through an opening that is assumed to exist at the bottom of the
RPV.

[Future applications of this project]
Development of Investigation
Technology for inside the
RPVActualequipment
investigation

Side accessinvestigation
methodBottomaccessinvestigation
methodInformation on the RPV interior(visual information, dose rate, etc.)

Study of fuel debris retrieval
method / equipment design©International Research Institute for Nuclear Decommissioning1. Research background and objectives

No.3[Implementation details of this project]

Testing will be used to verify the functionality required of processing technologies developed as of FY2021 for on-site
use as a processing technology for the top access investigation method.
In addition, a prototype of bottom access and investigation equipment to investigate the RPV interior will be
manufactured based on the results of conceptual studies obtained by FY2021, and tests will confirm the functions
necessary for on-site application.
Specifically, the following items will be studied and undergo technical development.
(1) Upgrading of processing technology for the top-access investigation method① Study of the functions necessary for the on-site application of processing technologies② Verification of the performance of the functions of element prototypes(2) Development of the bottom access investigation method① Formulation of a bottom access investigation plan and development plan for investigation equipment② Test manufacturing of bottom access and investigation equipment, functional verification testing©International Research Institute for Nuclear Decommissioning2. Goals

No.4(1) Upgrading of processing technology for the
top access investigation method⇒ For top access investigations, the AWJ and laser
cutting technologies selected as of FY2021 asprocessing methods for constructing access routes
into the shroud have reached the stage of conducting
prototype-level performance tests

TRL
7

Requirements forhandling at thesite

Site conditions(2) Development of the bottom accessinvestigation method⇒ As part of the development and engineering
process, the bottom access investigation method hasreached the stage of conducting prototype-level
performance tests for drones and telescopic accessequipment used to access the RPV interior

6

5

7
Applying for
permission andauthorization

On-siteinvestigation

6
Training andrehearsal
Equipment
manufacturing forinvestigation withactual equipment

5

Partial mockup testing

4

4

3

2

1

3

Basic design

Conceptual design

Study of equipment
specifications

Element testing

Element testing2

Partial mockup test
equipment
manufacturing
Detailed equipment
design based on site
conditions

1
Applicability
study©International Research Institute for Nuclear Decommissioning3. Action items, their inter-relation and relation to other studies No.5
Development of Technology
for Detailed Investigation
inside PCVDevelopment of Technology
for Gradually Increasing the
Scale of Fuel Debris
RetrievalStudy of fuel debris retrieval
method and equipment
Study of criticality control[input]- Access equipment specifications- Various constraints

Development of
Investigation Technology
for inside the RPVThis project

Detailed design,
equipment manufacturing,
mockup, etc.

[output]- Information on RPV interior andaccess routes(visual information, dose rate, etc.)

Actualequipment
investigation- Top access investigation- Bottom access investigation[input]- Results of the investigation of the upper part of the pedestal (lower part of the RPV)
(opening locations, structural conditions, etc.)

Development ofTechnology for Detailed
Investigation inside PCV©International Research Institute for Nuclear Decommissioning4. Implementation schedule

No.6
FY2022

Action items(1) Upgrading of processing technology
for the top access investigation
method
① Study of the functions necessary forthe on-site application of processing
technologies② Verification of the performance of thefunctions of element prototypes(2) Development of the bottom accessinvestigation method<Development of drone for Unit 1>① Formulation of bottom
access/investigation plan anddevelopment plan foraccess/investigation equipment② Test manufacturing of bottom
access/investigation equipment andfunctional verification testing<Development of telescopic accessequipment for Units 2 and 3>① Formulation of bottom
access/investigation plan anddevelopment plan foraccess/investigation equipment② Test manufacturing of bottom accessand investigation equipment,functional verification testing

1Q

2Q

Study of issues and countermeasuresfor processing technologies

Development planning

Study of prototype specifications

3Q

4Q

The production period was
extended beyond theoriginal plan due to delayeddelivery times of parts(*).

Verification andevaluation of functions
performance of thefunctions testing

Prototype design
Prototype manufacturing

Investigation anddevelopment planning
Study of investigation and development plan

The production period was
extended beyond theoriginal plan due to delayeddelivery times of parts(*).

Update of investigation anddevelopment plan

Study of investigation plan

Prototype manufacturing

Study of prototype specifications
Prototype design

Verification andevaluation of functions
Functionality verification testing

Study of investigation and development plan

Study of investigation plan

Investigation anddevelopment planning

Update of investigation anddevelopment plan

Study of investigation and development plan
Study of investigation plan and manufacturing
Functionality verification testing©International Research Institute for Nuclear Decommissioning(*) Some countries producing materials and parts underwent lockdown due to COVID-19, resulting in longer delivery times for parts.

5. Project organization chart

No.7

This project aims to develop technology for investigation inside the RPV. The interface with each development project teamis of the utmost importance. Therefore, IRID Head Office, Toshiba ESS, and Hitachi GE will work together to develop a safe,
reliable, logical, rapid, and site-oriented fuel debris retrieval technology for 1F, through mutual technological cooperation among
IRID Japanese plant component manufacturers, in order to analyze the on-site situation and to develop a series of measuresthat are consistent with the fuel debris retrieval plan, etc.
International Research Institute for Nuclear
Decommissioning (Head Office)Tokyo Electric Power Company Holdings, Inc.

○ Formulation of overall plan and technological supervision○ Technological management of technology development progress, etc.

○ Adjustments for on-site applicability

Toshiba Energy Systems & Solutions Corporation

Hitachi-GE Nuclear Energy, Ltd.

(2) Development of the bottom accessinvestigation method① Formulation of bottom access/investigation
plan and development plan foraccess/investigation equipment② Conceptual study of bottom access andinvestigation equipment(1) Upgrading of processing technology for the topaccess investigation method(2) Development of the bottom access investigation
method① Formulation of bottom access/investigation
plan and development plan foraccess/investigation equipment② Test manufacturing of bottom access andinvestigation equipment, functionalverification testing

Partner development project teams

Development of Technology for Gradually
Increasing the Scale of Fuel Debris Retrieval

Development of Technology for Detailed
Investigation inside PCV

Sugino Machine Ltd.
- (1) Structural design for upgrading the processing technology for the top-accessinvestigation method- (2) Structural design for the development of the bottom access investigation method
Hitachi Plant Construction, Ltd.
- (1) Technological study for upgrading the processing technology for the top-accessinvestigation method- (2) Technological study for the development of the bottom access investigation method
Toko Corporation / Chugai Technos Corporation- (2) Structural design for the development of the bottom access investigation method©International Research Institute for Nuclear Decommissioning6. Implementation details

No.8(1) Upgrading of processing technology for the top-access investigation method<Implementation details up to FY2021>
The focus was narrowed down to improved abrasive waterjet (AWJ) cutting and laser cutting, as both methods produce less secondary
waste than conventional AWJ cutting, and efforts were made to further refine the selected methods.

<Summary of implementation in FY2022>① Study of the functions necessary for the on-site application of processing technologies
The application of AWJ cutting and laser cutting on actual equipment was studied, issues regarding remote processing and thefunctions required for the equipment were reviewed, and the details of element prototyping were examined to verify these issues.
② Verification of the performance of the functions of element prototypes
A prototype was designed and manufactured, and its performance of the functions was confirmed to be satisfactory.

<Implementation details for FY2022>
Implementation details

Processing
technology①

Study of issues and countermeasures forprocessing technologies

AWJ②

Processing
technology

Laser

Implementation details①

Study of issues and countermeasures forprocessing technologies

Study of development plan②

Study of development plan③

Specification study, design, and test
manufacturing of remote equipment considering
actual equipment③

Specification study, design, and partial element
prototyping of abrasive feed rate stabilization
mechanism④

Functional verification testing and combined
operations verification testing for the laser cutting
device (prototype)④

Study, design, and partial element prototypingof nozzle maintenance method⑤

Functional verification testing of each element
prototype①

Study of patterns of uncollectible connecting
guide pipes

Common©International Research Institute for Nuclear Decommissioning6. Implementation details

No.9(1) Upgrading of processing technology for the top-access investigation method

1) Results as of FY2021 (Overall summary)With investigation of the RPV interior via the top access investigation
method, processing technology was developed to create a minimum
Φ140 mm opening in the reactor inner structure in order to establish
an access route.
Work cell

Airlock cell

Boundary function
maintaining equipment

Major results as of FY2021 and implementation details for FY2022
As of
FY2019- Verified that AWJ cutting can be used to cut reactor internals- Verified via prototype that operation can be conducted with remoteequipment- An issue of approximately 8.8 tons of secondary waste (abrasive use)

FY2020- Studied improvements to AWJ cutting and the applicability of otherprocessing technologies to reduce secondary waste (Target: Less than
500 kg of secondary waste)- The cutting capacity of AWJ cutting has improved by implementing smaller
nozzles that enable insertion into narrow areas and placement closer tothe workpiece (secondary waste volume reduced to approximately 1.3
tons)- Testing verified laser cutting as another processing technology for verticalcutting (WJ, hole saws, and disc saws are not applicable)
Laser cutting is not applicable for horizontal cutting due to difficulties withinserting the nozzle into narrow areas

FY2021- AWJ cutting was studied to reduce secondary waste, and laser cutting
was studied to be applied to all cutting points of the in-core structure- AWJ cutting was tested under low abrasive feed conditions, andsecondary waste was reduced to approximately 0.3 tons (target of 500 kg
was achieved)- Laser cutting is expected to be applicable to all parts within the core
structure due to the reduced nozzle size

ToolboxToolbox side gate
valveWork cell

Well cover
PCV head

Boundary guidepipe side gate
valve
Boundary guidepipe

RPV head

Steam dryer

Opening: Φ140
mm or more

- The low abrasive feed in AWJ cutting caused a feed instability event

Steam separator
Shroud head

Cutting head

Reactor internals that arepart of this project

RPV thermal insulation

Toolbox transport
carrier

Treatment target

Drawing of steam separator opening- The feasibility of remote equipment with laser cutting requires verification

FY2022- AWJ cutting: Abrasive feed stabilization study and element testingNozzle and camera remote replacement method study- Laser cutting: Remote equipment study, prototype production, andFunctional verification testing

Outline of in-core structure opening©International Research Institute for Nuclear Decommissioning6. Implementation details

No.10(1) Upgrading of processing technology for the top-access investigation method
1) Results through FY2021 (Summary of FY2020 and FY2021 results)

Results of studies through FY2019 confirmed that AWJ cutting is capable of cutting reactor internals, but the large amount of secondary waste was an issue.
Therefore, in FY2020 and FY2021, studies focused on processing technologies with low volumes of secondary waste. (Target: Less than 500 kg of secondary waste)

FY20201) The following five methods were selected based on a desk study to narrow down the applicable processing technologies.
① AWJ cutting (small nozzle) ② Water jet cutting ③ Laser cutting ④ Hole saw ⑤ Disk saw
2) Tests were conducted to evaluate the applicability of the five selected methods, and ① AWJ cutting and ③ laser cutting were evaluated as applicable methods.
① AWJ cutting is designed to use a small nozzle surrounded by three steam separator cylinders, enabling improved operational conditions and reducing theamount of secondary waste.

<Operational conditions until 2019>
Conventional nozzle

Conventional nozzle(yellow)

Estimatedsecondary waste
8,810 kg

Standoff: 78
to 108 mm<Operational conditions with a small nozzle>
Small nozzle

Small nozzle (yellow)

Estimatedsecondary waste
1,293 kg

Standoff: 1 to56 mm
Drawing of steam separator cutting

Drawing of steam separator cutting② Laser cutting was confirmed to be applicable for vertical cutting. Design and manufacturing of a nozzle capable of horizontal cutting is required for FY2021.

FY2021

1) Further reductions of secondary waste in AWJ cutting and the application of laser cutting to all cutting lines of
the in-core structure were studied and confirmed through testing.
① Verified an abrasive feed rate with good cutting efficiency and confirmed that AWJ cutting was possible
under those operational conditions, providing the prospect of achieving a secondary waste volume targetof 500 kg.
Improved abrasive feed rate

Conventional abrasive feed conditions
500 g/min

Conventional abrasive feed conditions
100 g/min② A nozzle to make horizontal laser cutting possible was designed and fabricated, providing theprospect of cutting all in-core structure cutting lines. (The image on the left shows a horizontal cut.)NozzleEstimated secondarywaste
328 kgCutting area

Steam separator main bodyLaser cutting Image of cutting the steam separator©International Research Institute for Nuclear Decommissioning6. Implementation details

No.11(1) Upgrading of processing technology for the top-access investigation method

No.

Major
items

Intermediate
items

Development issues

1

Laser cutting2) Review of issues and development plans for upgrading processing technologies (1/3)

Processing
equipment

Feasibility of the remote equipment considering
actual equipment

Action policy (plan)

Design and manufacture a prototypeof remote equipment that
- Remote insertion of a cutting nozzle into narrowincorporates countermeasures to thespacesissues listed on the left, and confirm- Verification method for the status of the treatment
the feasibility of remote equipment
target before and after cutting
by simulating the assumed height of(Concerns about camera visibility and lens damage)- Fiber transmission lines for actual equipment length the actual equipment (max. 18 m).

Conducted
or not in
FY2022

FY2022 test/action items

Conducted- Design and prototyping of remoteequipment considering actual equipment- Functional verification testing andcombined testing of remote equipment(Verification of remote insertability, camera
view range, laser power, etc.)(Concerns about attenuation of laser output)- Incorporation into the fiber drum(Concerns about bending resistance of fiber)- Application of slip rings to high power lasers (8 kW)

2⇒ See slides No.16 to 27

Nozzle maintenance(Nozzle durability was verified without issue inFY2021, but this is a countermeasure against
nozzle failure)

Study nozzle maintenance methods.

－(None)

3

Processing
technology

Effect of dross on cutting(Seek cutting parameters that facilitate drossdispersion and reduce the risk of re-welding)

Optimize parameters such as assist
gas flow rate and direction, laser
power and nozzle speed, and verify
conditions that facilitate drossdispersal.

－(None)

4

Environment
simulation

Influence of the actual operating environment(Temperature, humidity, and atmosphericconditions)Examine the impact of the actual
operating environment and, if
necessary, verify its impact throughtesting.

－(None)

Verification of
the impact onother systems

Assist gas restrictions(Type, flow rate)

Verify the limitations of the actual
equipment and test as necessary.

Conducted

5－(Nozzle maintenance methods for AWJ cutting
will be studied, and laser cutting will use thoseresults. Expected to be implemented in FY2024
or later.)－(Conditions that permit operation without rewelding were confirmed in FY2021 testing.
After confirming the feasibility of the remoteequipment, further risk reduction and thenecessity of such is expected to be consideredin FY2024 or later.)－(Will be evaluated after verifying the feasibilityof the remote equipment and is expected to be
conducted in FY2024 or later.)- Verification of limitations of actual
equipment (desk study)⇒ See slide No.17©International Research Institute for Nuclear Decommissioning6. Implementation details

No.12(1) Upgrading of processing technology for the top-access investigation method

No.

Major
items

Intermediate
items

Development issues

Action policy (plan)

Conducted
or not in
FY2022

6

AWJ cutting2) Review of issues and development plans for upgrading processing technologies (2/3)

Processing
equipment

Feasibility of the remote equipment considering
actual equipment

The feasibility of the remoteequipment considering actual
equipment was confirmed throughFY2019, so the impact of changes
since FY2019 will be verified.

－(None)

Abrasive feed rate stabilization

Confirm whether a stable supply ofabrasive is possible with remoteequipment considering actual
equipment. Variable abrasive feed
rates will also be studied.

Conducted

7(The abrasive feed rate was set at 100 g/min in
FY2021, but verification is required as to whether astable supply is attainable with remote equipment
considering actual equipment.)

FY2022 test/action items－(The main change from FY2019 is nozzle
shape and the impact of which is assumed tobe minor. The results of the No.1 laser cutting
prototype will be deployed to AWJ cutting in
FY2024 and beyond, if necessary.)- Study of abrasive feed rate stabilization- Design and manufacture of partial
element prototypes- Functional verification testing of partial
element prototypes⇒ See slides No.28 to 32

8

Nozzle maintenanceStudy nozzle maintenance methods.

(FY2021 test results set nozzle life at approximately 8hours, while the expected operation time on actual
equipment is approximately 42 hours(for angled nozzles), so maintenance is required.)(A change to the material of the severely
damaged mixer part (SUS630 →Carbide) could be considered, but it is
not assumed to be able to last for theactual operation time)

Conducted- Study of nozzle maintenance method- Design and prototyping of partial element
prototypes- Functional verification testing of partial
element prototypes⇒ See slides No.33 to 36

9

Abrasive
reduction

Further reduction in the amount of abrasive
used- Further exploration into the appropriateabrasive feed rate value- Selection of optimum nozzle shape- Reduction in the number of cuts for locations
that require numerous cuts

Because the target abrasive amountof 500 kg or less has been achieved,
the response has been set to HOLD
and the need for a response will bereconfirmed based on the results of
responses to other issues.

－(None)－(HOLD)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.13(1) Upgrading of processing technology for the top-access investigation method

No.

Major
items

Intermedia
te items

10

Common2) Review of issues and development plans for upgrading processing technologies (3/3)

Processing
equipment

11

Development issues

Treatment of cut pieces (transfer)

Conducted
or not in
FY2022

Study the cut piece transfer method.

－(None)(In FY2021 tests, cut pieces interfered with cutting atother locations)Radiation resistance of components

12

Action policy (plan)

Durability of components

Conduct irradiation tests oncomponents at risk of damage, andselect appropriate components.

－(None)

Identify hoses and othercomponents at risk of deteriorationand verify their durability.

－(None)(The durability of each nozzle wasconfirmed in FY2021)

13

14

Risk
response

Installation method in case of damaged anddeformed reactor internals

Since the process of inserting thenozzle between the three steam
separator cylinders is considered topose a high risk of failed installation
due to deformation, methods for
expanding the space between thethree cylinders will be examined.

－(None)

Responses to uncollectible connecting guidepipes

Examine patterns where collection
was not possible and consider
countermeasures as necessary.

Conducted

FY2022 test/action items－(Development issues for the equipment bodywill be prioritized and measures for ancillaryequipment will be implemented; expected to be
conducted in FY2024 or later)－(It was deemed reasonable to verify such after
determining the configuration of equipment for
remote equipment; expected to be conductedin FY2024 or later)－(Since nozzles with a high risk of deterioration
were confirmed in FY2021, it was determinedreasonable to verify other components using
products equivalent to actual equipment;
expected to be conducted in FY2024 or later.)－(The next phase includes a detailed design ofequipment reflecting site conditions; expected
to be implemented in FY2024 or later.)- Examination of uncollectable patterns(Desk study)⇒ See slide No.37©International Research Institute for Nuclear Decommissioning6. Implementation details

No.14(1) Upgrading of processing technology for the top-access investigation method
3) Upgrading of processing technology Development flow (draft)Category

As of FY2021
TRL: 3 to 4

FY2022

FY2023 (*)

TRL: 4- Lasers achieved TRL 3
TRL
in FY2020 and FY2021.
attainm - The
feasibility of AWJ
ent level remote equipment

TRL: 5The objective is to reach a stage where prototypelevel performance tests can be conducted.

achieved TRL 4 by
FY2019.

－Major achievements:
Verification ofprocessing technology

Laser

FY2024 and later (*)- Prospect that everything
to be processed can be
cut.

Desk study

Design/Prototyping

Functionalverification
testing

Prototype production and functional verification testing of
remote equipment considering actual equipment(Issue No.1)- Examine the function - Reflect the- Conduct functionaland contents ofcontent ofverification testingelement prototypes.
examinations inof the prototype.
the design andcreate aAssist gas
prototype.
restrictions(Issue No.5)
If required, test in FY2024 or later

Laser and AWJ will betested on prototypes toconfirm the feasibilityof remote equipment.

Element
testing- Conduct
cutting tests
using a mockup of theactualequipment tobe processed.

- Use test
results toevaluateapplicability
to actualequipment.

TRL: 7

Using actual
equipment

Manufacturing and design of actual equipment / mockup
testing / training phase
Design and manufacturingof actual equipment

Evaluation

Simulation of actual
equipment via a prototype
Cutting test (Issue No.1)

TRL: 6

Mockup testing- Laser nozzle
maintenance(Issue No.2)- Influence of theactual operating
environment(Issue No.4)

Training

Reduction of the influence of drossduring cutting(Issue No.3) (Laser only)- Verify limitations withactual equipment.

CommonAWJ

Verify feasibility of
remote equipment

Prototype and functional verification verification ofabrasive feed rate stabilization mechanism(Issue No.7)- Feasibility of remote
Element prototyping and maintainability verification ofequipment was
nozzle maintenance mechanism (Issue No.8)
confirmed with a
Examine methods of- Reflect the- Conduct functional
prototype as of FY2019.
stabilizing andcontent ofverification testing
adjusting theexaminations inof element
Abrasive use reduced
abrasive feed rate.
the element
prototypes.
(target achieved)
prototype- Examine nozzle
design and- Prospect of achieving
maintenancecreatethe target of using lessmethods.
prototypes.
than 500 kg of abrasive.

－

Study of patternsof uncollectible
connecting guidepipes(Issue No.14)

Cutting test using
prototype(Issue No.7)- Element
testing will be
conducted asneeded basedon FY2022
results.

- Use test
results toevaluateapplicability
to actualequipment.

Design, manufacturing, andmockup testing of remote
maintenance equipment (Issue
No.8)

Design, manufacturing, andmockup testing of cutting piecetreatment tools (Issue No.10)

Examination of installation method
in case of deformed reactor
internals (Issue No.13)

If necessary, measures will be considered and reflected in the design in FY2024 or later
Equipment durability(Issue No.12)

Radiation resistance ofcomponents (Issue
No.11)©International Research Institute for Nuclear Decommissioning(*) Plans for FY2023 and beyond are proposals from the project implementer and have not been decided.

6. Implementation details

No.15(1) Upgrading of processing technology for the top-access investigation method
4) Upgrading of processing technology Implementation details

Laser cutting[Implementation details in FY2022]- Examination of prototype specifications- Design and prototyping of remoteequipment considering actual equipment- Functional verification testing andcombined operations testing of remoteequipment

Work cell

Airlock cell

Drum

Boundary function
maintaining
equipment
ToolboxConnecting guidepipe

Toolbox side gate
valve

Hoisting
equipment

Laser
nozzleTool transfer
mechanism

Work cell

Toolbox transport
carrier

Well cover
PCV head

Boundary guidepipe side gatevalve

RPV thermal
insulation

Boundary guidepipe

RPV head

Examination system

Steam dryer

Toolhead

Reactor internals processing equipment
Steam separator

AWJ cutting[Implementation details in FY2022]- Study of abrasive feed rate stabilization- Study of nozzle maintenance method- Specification study of each element
prototype- Design and manufacture of element
prototypes- Functional verification testing of element
prototypes

Treatment target

Connecting
guide pipe

Shroud head

Processing
equipment

Conceptual drawing of the top access investigation method

AWJ
nozzleToolhead

Common[Implementation details in FY2022]- Study of patterns of uncollectible connecting guide pipe

Toolhead©International Research Institute for Nuclear Decommissioning6. Implementation details

No.16(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology➀ Specification study and design of laser cutting device (prototype) <Specification study and design of prototypes>➀ Specifications[Composition]<Equipment overview>
Equipment to open the steam dryer, steam separator, and shroud head at the planned
opening position in the work cell (directly above the RPV reserve nozzle)
Drum

Hoisting
equipment

Drum

Approx. 3600 mm

Connecting guide
pipe
Hoist
mechanism

Connecting guidepipe
Toggle unlock
mechanism

Toggle unlock
detectionmechanism

Toggle lockmechanism
Elevation detection
rollerFixing jig
Processing position
adjustment
mechanism

Connecting guidepipe clamping
mechanismApprox. 2,000 mm

Tool transfer
mechanism

Toggle lockdetectionmechanism

Toolhead

Toolhead

Backward
reaction force
receiverApprox. 620 mm

Connecting
guide pipe

θ-axisθ-axisToggleWhen toggle is When toggle
unlockedlockedα-axis

700 mmΦ138.5 mm
R-axisLaser nozzle(straight nozzle)

Forwardreaction force
receiverLaser nozzle(angle nozzle)- The laser cutting device consists of a toolhead with laser nozzle, connecting guide
pipes, hoisting equipment, a drum, and a tool transfer mechanism.
- A laser oscillator is installed separately.
[Toolhead]- The toolhead (for angle nozzles) consists of a laser nozzle, a forward/backward
reaction force receiver, and a θ-axis motor that swivels the toolhead.
- The toolhead (for straight nozzles) consists of a laser nozzle, α-axis and R-axis
motors that adjust the position and angle of the laser nozzle, and a θ-axis motor thatswivels the toolhead.
[Connecting guide pipe]- The guide pipe consists of a series of 700 mm long pipes with the toolheadconnected at the end.
The other end is attached to the drum.
- The drum rotates to feed or wind the connecting guide pipe with attached toolhead.
- Each joint locks together so that the axes of the upper and lower pipes are aligned
when passing through the hoisting mechanism, and the toolhead is supported.
[Hoisting equipment]- This component consists of a hoisting roller and a toggle lock mechanism to assist in
the lifting and lowering of the connecting guide pipe.
[Drum]- Its function is to feed and wind the connecting guide pipe.
- The horizontal position of the drum can be adjusted (drum horizontal axis and drum
forward-backward axis).
[Tool transfer mechanism]- Its function is to adjust the horizontal position of the in-core structure processing
equipment (X and Y tool travel axes).
② Main design points for laser cutting[Hoisting apparatus (drum + hoisting equipment)]① Fiber integrated into equipment⇒ See slide No.18② Design with high-power laser transmission(slip ring and rotary coupler inclusion study, etc.)③ Design featuring cooling water and various gas systems for the laser nozzle[Toolhead]⇒ See slide No.17- Newly designed for lasers.

©International Research Institute for Nuclear Decommissioning6. Implementation details

No.17(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology② Toolhead design[Main design details]- Design for each drive axis (movement range/speed): Drive shaft designed for operations under the operational conditions
established from the results of FY2021 tests.

Toolhead(angle nozzle)

Toolhead(straight nozzle)- Reaction force receiver design: Designed with a mechanism to reduce toolhead vibration (for angle nozzles)
from the reaction force of assist gas injection.
Reaction force vibration is small with the straight nozzle toolhead, so it wasdetermined that a reaction force receiver was unnecessary for straightnozzles.

Swivel axis
(θ-axis)Backward
reaction force
receiver- Laser transmission system design: Designed to connect the fiber cable within the toolhead to the laser nozzle atthe tip of the toolhead.

- Equipped with a camera: A camera is installed to check toolhead position for easier access and tocheck the treatment target.

Tilt axis (α-axis)
Laser nozzle(angle nozzle)

Camera- Assist gas restrictions: Nitrogen, which is currently sealed in the RPV, will be used as the assist gas Tilt axis (R-axis)
and the design allows for connection of a nitrogen cylinder.
The assist gas flow rate is expected to be higher than the current flow rate of
the nitrogen inside the RPV, but possible operational countermeasures such
Laser nozzle
as intermittent disconnection are being considered, and it has been(straight nozzle)
determined that such countermeasures do not need to be reflected in theequipment design.
Operational countermeasures are expected to be thoroughly considered in the
TRL 5 phase, when the actual equipment information is input.

CameraForwardreaction force
receiverToolhead (laser cutting)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.18(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology Drum③ High-power laser transmission design

Rotary coupler(Required for connection
from laser oscillator to
drum (rotating body))(Rotates when theconnecting guide pipe islifted or lowered (red arrow))

Optical fiber- Core diameter:
Φ300 µm- Length: 50 m

Laseroscillator
FY2021 laser
head prototype

Configuration at the time of FY2021
element testing

Connecting guide pipe

Laser head

Optical fiber- Core diameter:
Φ400 µm- Length: 30 m

Optical fiber- Core diameter:Φ200 µm- Length: 60 m

Laser
oscillator

Configuration of laser cutting device for
actual equipment•

The FY2021 laser head prototype uses optical fiber (core diameter: Φ300 µm, length: 50 m) attached to the laser oscillator, and cutting tests
verified its potential for application.

•

Consider the following when designing for actual equipment:① For the optical fiber connecting the oscillator to the drum, select fiber with a core diameter of Φ200 µm and assume a transmission distanceof approximately 50 m.
② Use a rotating coupler to connect the optical fiber from the laser oscillator to the drum, as the drum is a rotating body.
The core diameter on the drum side must be 200 µm larger than that on the oscillator side to allow for fiber misalignment in the rotating
coupler section.

•

Compared to the FY2021 prototype, the diameter of the optical fiber core connected to the laser head has increased (laser beam diameterhas increased and power density has decreased), and there is concern that cutting performance will decrease.

•

Operational countermeasures to the reduction in power density can be considered, such as lowering the nozzle speed (cutting speed) during
operation, and cutting performance tests must be conducted to verify whether cutting is possible and the conditions under which cutting ispossible.
©International Research Institute for Nuclear Decommissioning6. Implementation details

No.19(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology④ Functional verification testing plan for the laser cutting device (1/2)
Test items are extracted for each target area, focusing on parameters that affectcutting performance.
No.

Target area

1

Drum,
hoisting
equipment
(*1)

2

3

Connecting
guide pipe

Relatedelements

Test item- Drum rotation Checking the accuracy ofaxis
the speed of lifting and- Drumlowering the connecting
horizontal
guide pipe
axis
Checking the lifting and- Hoisting
lowering range of theequipment
connecting guide pipe

- Toggle

Tool transfer - Tool travel
mechanismaxis X- Tool travelaxis Y

Equipment in the tableon the left

Drum rotation axis

Drum

Drum horizontal axis

Connecting guide pipe
Hoisting
equipment

Remarks
A parameter that affects nozzle speed during steam
separator cutting (vertical cutting) and is related to
cutting performance.

Drum forwardbackward axis(*2)

The connecting guide pipe must be able to be lifted
and lowered to the cutting position for processing.

Checking the accuracy ofthe lifting and lowering
position of the connecting
guide pipe

A parameter related to cutting performance, as it
affects standoff.

Checking the distance of
one inching operation

A parameter that affects the accuracy of
adjustments to vertical positioning and is related tostandoff setting and other cutting performancefactors. Actual performance is measured. (Nocriteria)

Tool travel axis Y(*2)

Tool travel axis X

Fixing jig(*3)

Tool transfer
mechanism

This item does not affect cutting performance, but it
Checking the amount ofconnecting guide pipe sway is related to opening passability and actual
performance is measured for reference.
at no reaction force[Reference measurement]

Checking the amount ofconnecting guide pipe
deflection to reaction forcesfrom the assist gas

A parameter related to cutting performance, asdeflection in a toolhead without a reaction force
receiver (straight nozzle) may affect standoff, etc.
However, this can be compensated for by using the
α/R-axis of the toolhead, so the actual value shall bemeasured in this functional test.

Operating range/accuracy[Reference measurement]

No changes have been made from the FY2019
design that was verified as feasible, and so
verification is deemed unnecessary.
Only the operating range of tool travel axis Y ismeasured for reference because the axis isoperated manually and a simplified model is used.
Tool travel axis X is operated digitally for workability
considerations and the operating range andaccuracy are measured as a reference.

(*1) When lowering the connecting guide pipe, the drum and hoisting mechanism shall be interlocked and checked at that time.

θ-axisToolhead
α-axisCutting nozzle
R-axis(*2):
Remote digital operation isrequired for the actual
equipment, but axes will
be manually operated
during these tests.
(*3):
Remote digital operation isrequired for the actual
equipment, but these tests
will use a simplified jig
shape and the axes will be
operated manually.

Reactor internals processing equipment©International Research Institute for Nuclear Decommissioning6. Implementation details

No.20(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology④ Functional verification testing plan for the laser cutting device (2/2)

Test items are extracted for each target area, focusing on parameters that affectcutting performance.
No.

Target area

Related elements

4

Fixing jig- Positioning axis X,
Y- Clamping axis

Test item

Remarks

Measurement operating No changes have been made from the
FY2019 design that was verified as feasible,
range
and so verification is deemed unnecessary.
[Reference
Only the operating range is measured formeasurement]
reference because each axis is operated
manually and a simplified model is used.

5

Toolhead(Common *1)

6

Toolhead- Laser irradiation
section- Assist gas injection Measuring assist gas
sectionpressure / flow rate

Toolhead(Angle nozzle only)

A parameter related to cutting performance,
and actual performance is measured. (Nocriteria)

Checking camera
image

No direct impact on cutting performance, butverify that there are no issues with the image.

- θ-axis

Drive speed accuracy

A parameter that affects nozzle speed in all
cutting except steam separator cutting (verticalcutting) and is related to cutting performance.

Measuring position
setting accuracy

A parameter related to cutting performancefactors, such as standoff and laser incidence
angle during steam separator cutting (verticalcutting).

Measuring position
setting accuracy

The positioning accuracy for a given nozzle
posture (angle and position) considered foreach cutting target is a parameter that affects
cutting performance, such as standoff andlaser incidence angle.

- α/R axes

- Backward reaction
force receiver(*2):
Remote digital operation isrequired for the actual
equipment, but these tests
will use a simplified jig
shape and the axes will be
operated manually.

Fixing jig(*2)
Positioning axis X, Y
Clamp axis

A parameter related to cutting performance,
and actual performance is measured. (Nocriteria)- Camera(Straight nozzle
only)

7

Measuring laser output

Equipment in the tableon the left

Measurement operating A parameter related to cutting performance
because if the operating range is less than therange
design value, it will not remain near thesurrounding structure and deflection will
increase.

(*1) Testing items that require verification for both straight and angled nozzle toolheads.

Backward
reaction force
receiverθ-axisθ-axisα-axisCutting nozzle
R-axisCameraCameraLaser irradiation section/ assist gas injection
sectionLaser irradiation section/ assist gas injection
sectionToolhead

Toolhead(straight nozzle)(angle nozzle)

Reactor internals processing equipment©International Research Institute for Nuclear Decommissioning6. Implementation details

No.21(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑤ Results of functional verification tests of the laser cuttingConnecting
device (1/4)
guide pipe
[Drums and hoisting equipment]<Test outline>
The following items were checked by using the drum andhoisting equipment to lift and lower the connecting guide pipe.
① The accuracy of the speed of lifting and lowering theconnecting guide pipe
② The connecting guide pipe hoisting range③ The accuracy of the lifting and lowering position ofconnecting guide pipe
④ The distance of one inching operating<Test results>
Test item

Assessment criteria

Drum
Hoisting
equipment
Hoisting equipment

Drum and hoisting equipment
Test method

Results(○: satisfies the assessment criteria)① The accuracy of the speed of lifting The measured value must be
and lowering the connecting guide within ±10% of the set value (60,pipe120, 300 mm/min).

Operate the device for a predetermined
distance and measure the time with astopwatch.

② The connecting guide pipe hoisting16192 mm or greater
range

Use a tape measure to measure operating
Measured stroke: 16570 mm
distance at full stroke.

③ The accuracy of the lifting and
The measured value must be
lowering position of the connecting within ±5 mm of the target
guide pipe
position.

④ The distance of one inching
operating

Use a tape measure to measure thedeviation from the target position.

No assessment criteria as this is a Use a tape measure or metal ruler toreference measurement.
measure the operating distance.

Hoisting equipment- Accuracy of hoisting speed: -1.7% to +2.3%- Accuracy of lowering speed: +2.0% to +4.8%

Difference between measured and target values
Target position 13544.2 mm (height of steam dryer): -2.2 mm
Target position 15001 mm (height of top of steam separator): 2.5 mm
Target position 16618 mm (height of bottom of steam
separator): -3.0 mm
Operating distance of one inching: 0.2 mm<Conclusion>⇒ The drum and hoisting equipment are determined to satisfy the prescribed functions.
©International Research Institute for Nuclear Decommissioning6. Implementation details

No.22(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑤ Results of functional verification tests of the laser cutting
device (2/4)
Connecting[Connecting guide pipe]
guide pipe

<Test outline>
Lower the connecting guide pipe to the specified height andcheck the following items:① Checking the amount of connecting guide pipe sway atno reaction force② Check the amount of deflection in the connecting guidepipe from assist gas reaction force<Test results>

ToolheadFixing jig(*): The amount of deflection indicates the amount of movement of theconnecting guide pipe when subjected to the assist gas reaction force, based on
the position of the connecting guide pipe when not subject to assist gas reaction
force.

Test item

Assessment criteria

Connecting
guide pipe

Connecting guide pipe

Connecting guide pipe and toolhead
Results(○: satisfies the assessment criteria)

Test method① Checking the amount of
Use a laser level and metal ruler to
No assessment criteria as this isconnecting guide pipe sway at no
measure the amount of sway in the guidea reference measurement.
reaction forcepipe.

① (Steam dryer bottom plate) position: 18.0 mm② (Top of steam separator) position: 27.3 mm③ (Bottom of steam separator) position: 36.5 mm④ Lower edge position: 40.5 mm② Amount of deflection of theconnecting guide pipe due toassist gas reaction force(*)① (Steam dryer bottom plate) position: 1.0 mm② (Top of steam separator) position: 2.1 to 4.0 mm③ (Bottom of steam separator) position: 3.0 to 4.5 mm④ Lower edge position: 3.5 to 4.5 mm

No assessment criteria as this is Use a laser level and metal ruler toa reference measurement.
measure the deflection of the guide pipe.

<Conclusion>⇒ Verified the actual values of runout and deflection of the connecting guide pipe.
These values must be reflected in future designs and operation of the actual equipment.
©International Research Institute for Nuclear Decommissioning6. Implementation details

No.23(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑤ Results of functional verification tests of the laser
cutting device (3/4)[Straight nozzle toolhead]<Test outline>

θ-axisToolhead

Straight
nozzleα-axisPower meter

R-axisOperate the toolhead (straight) and check the following items:① Accuracy of θ-axis rotation speed, ② Accuracy of α/R-axis position setting③ Accuracy of θ-axis position setting, ④ α/R-axis travel range⑤ θ-axis travel range, ⑥ Assist gas pressure and flow rate measurement⑦ Laser output measurement

SensorStraight
nozzle<Test results> (*): θ-axis rotation speed setting values: 20, 40, 90, 110, 190, 280, 350, 510 (°/min)
Test item① Accuracy of θ-axis rotation
speed

Assessment criteria
The measured value must be within±10% of the set value (*).

Straight nozzle toolhead

Test method
Operate the device for a predetermined distance andmeasure the time with a stopwatch.

The measured value must be within the
Use a caliper and angle gauge to measure position during② Accuracy of α/R-axis position following values to the target position.
settingNozzle tip position within ±1 mm
operation.
Nozzle tip angle within ±1°

Laser output measurement setup
Results(○: satisfies the assessment criteria)

Measured value relative to setting value: -1.1% to 1.5%
- Misalignment: ±0.0 mm- Angular misalignment: -0.6° to +0.6°

The measured value must be within ±1° Use a tape measure to measure the deviation from theof the target position.
target position.
The stroke must be within the following
values:Check that equipment operates up to the soft limit set for- α-axis: -6 mm to +13 mm
the stroke.
- R-axis: -17 mm to +16 mm

Amount of deviation from the target position:+180° position: ±0°, -180° position: ±0°⑤ θ-axis travel range

Must operate at 370° or more.

Use a tape measure to measure operating distance.

Actual measured value: 376.37°⑥ Assist gas pressure & flowrate measurement

No assessment criteria as this is areference measurement.

Use the pressure indicator and flow meter installed on thesystem to measure.

- Pressure: 0.63 MPa- Flow rate: 810 L/min⑦ Laser output measurement

No assessment criteria as this is areference measurement.
(FY2021 cutting tests were conductedwith an output of 7.2 kW)

Use a power meter to measure output. (Thermal
measurement method)

Actual measured value: 7.75 kW③ Positioning accuracy of θ-axis④ α/R-axis travel range

Verified that equipment operates up to the soft limit set for thedesign stroke.

<Conclusion>⇒ The toolhead for straight nozzles is deemed to satisfy the prescribed functions.
(Laser output loss is comparable to FY2021 estimated levels, so no issue exists.)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.24(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑤ Results of functional verification tests of the laser
cutting device (4/4)
Backward
reaction force[Angle nozzle toolhead]

Sensorθ-axisPower meterreceiver<Test outline>
Operate the toolhead (angle) and check the following items:① Accuracy of θ-axis rotation speed② Accuracy of θ-axis position setting③ Backward reaction force receiver travel range④ Assist gas pressure and flow rate measurement⑤ Laser output measurement

Toolhead<Test results>
Test item① Accuracy of θ-axis rotationspeed② Accuracy of θ-axis position
setting③ Backward reaction force
receiver travel range

Angle nozzle toolhead
Assessment criteria
The measured value must bewithin ±10% of the set value(190°/min).
The measured value must bewithin ±1° of the target
position.
Actual measurement shall be
13±0.4 mm.

Test method

Laser output measurement setup

Results(○: satisfies the assessment criteria)

Operate the device for a predetermined distance and Accuracy of measured value relative to set value: -0.1%
measure the time with a stopwatch.
to -0.2%
Use a tape measure to measure the deviation fromthe target position.

Amount of deviation from the target position:+180° position: +0.43°, -180° position: +0.02°

Use calipers to measure operating distance.

Actual measurement: 12.61 to 12.63 mm④ Assist gas pressure & flow rate No assessment criteria as this is Use the pressure indicator and flow meter installedmeasurementa reference measurement.
on the system to measure.

⑤ Laser output measurement

Angle
nozzleAngle
nozzleNo assessment criteria as this isa reference measurement.
Use a power meter to measure output. (Thermal(FY2021 cutting tests were
measurement method)
conducted with an output of 7.2
kW)- Pressure: 0.68 MPa- Flow rate: 890 L/min

Actual measured value: 7.24 kW<Conclusion>⇒ The toolhead for angle nozzles is deemed to satisfy the prescribed functions.
(Laser output loss is comparable to FY2021 estimated levels, so no issue exists. )©International Research Institute for Nuclear Decommissioning6. Implementation details

No.25(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑥ Laser cutting device combined operations testing results (1/3)⇒ Tests are conducted in combination with each equipment to verify a series of operations with the assumed actual operating equipment.

No.

Actual workflow(Test content)
1.1 Adjust drum
and hoisting
equipment
position1

1.2 Set the X andY position ofprocessing
equipment (inthe toolbox)(*1)

Test results

Operations image
Drum horizontal
axis

Processing
equipment
Drum
Connecting guidepipeDrum forwardbackward axis(*1)
Tool travel axis Y(*2)(*1, *2) Manual axes for testing

Drum horizontal
axis

Hoisting equipment(○: satisfies the prescribedfunctions)- The position of the drum and hoisting
equipment align with the drum
forward-backward axis and the drum
horizontal axis.

DetailsDrum
Hoisting
equipment- Verified that X and Y positions of theprocessing equipment can be set.

Drum forwardbackward axis
Drum horizontal axis

Tool travel axis X

Adjusting drum and hoisting equipment position

Tool transfer mechanism- Verified that the toolhead can belowered to the fixing jig bysynchronizing it with the drum
Connecting guide pipe
horizontal axis.
Drum

Hoisting equipment

2. Lower thetoolhead to
fixing jig

Processing
equipment- Verified that lifting and lowering withthe hoisting equipment is possible
while the toggle lock is engaged.

Tool travel axis
Y

Tool travel axis X

Setting the X and Y
position of processing
equipment

Locked2Toolhead
Unlocked
Toolhead

Toggle mechanism for theconnecting guide pipe

Fixing jig
Fixing jig

Lowering the toolhead to fixing jig(*1): The toolbox was not used in the test.
©International Research Institute for Nuclear Decommissioning(The basic design of the toolbox has been completed as of FY2019 and is not subject to development in the FY2022 subsidy project)

6. Implementation details

No.26(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑥ Laser cutting device combined operations testing results (2/3)

No.

Actual workflow(Test content)

Operations image
Drum

3.1 Adjust theposition of the
fixing jig andtoolhead

Connecting guide pipe
Hoisting equipment
Tool travel axis Y

3.2 Insert thetoolhead into
the fixing jig

3

3.3 Lower
toolhead near
operationheightTool travel axis X
Tool transfer
mechanism

Connecting guide
pipe- Manufactured-inclamping mechanism- The fixing jig contains
a position adjustment
mechanism

Test results

4

4.2 Lower tooperationheightForwardreaction force
receiverToolhead- Verified that the connecting guidepipe can be lowered close tooperation height and secured inplace with the clamping mechanismon the fixing jig.

Forwardreaction force
receiverPhotographof actualequipment
Insertion
opening

Gap between thethree steam
separator cylinders(Insertion opening)

Cameraimage

Steam separator(Partial mockup)(*3) Simplified shapefor testing andmanual shaft
operations

Toolhead
Forward reaction
force receiver
Steam separator(Partial mockup)

Insertion of forward reaction force receiverInsertion
opening
Forwardreactionforce
receiverFixing jig (*3)

➀ Toolhead reaches near
operation height

Toolhead

4.1 Adjust the X/Yposition of thetoolhead

Details(○: satisfies the prescribedfunctions)- Camera images can be used toinsert the toolhead into the fixing jig.

- Confirmed that camera images canbe used to adjust position relative toa partial mockup of the steam
separator.
- Verified that the toolhead can belowered to operation height.

② Toolhead X and Y position
adjustment[Position adjustment method]- While rotating the toolhead,measure the distance from theforward reaction force receiverto the insertion opening at threelocations and at a pitch of 120°
(measured using camera
images).
- The fixing jig and tool transfer
mechanism adjust the X/Y tominimize the difference indistance measured (i.e., tominimize any misalignment
between the insertion opening
and toolhead).

Steam separator(Partial mockup)

Forwardreactionforce
receiver③ Insertion of the toolhead forward
reaction force receiver©International Research Institute for Nuclear Decommissioning6. Implementation details

No.27(1) Upgrading of processing technology for the top-access investigation method
5) Results of laser cutting technology⑥ Laser cutting device combined operations testing results (3/3)

No.

Actual workflow(Test content)-

Target of cutting
treatment

Test results

Operation details

Details(○: satisfies the prescribedfunctions)Not applicable to this study- Verified that camera images can beused to return the toolhead to thespecified height.

Drum

5.1 Raise
toolhead

Connecting guide pipe
Hoisting
equipment

5.2 Release fromfixing jig

Fixing jig

Toolhead- Verified that the hoisting equipment
can lift the toolhead while the toggle
is unlocked.
ToolheadFixing jig

5.3 Raise
toolhead(recovery)

LockedConnecting guide pipe

① Toolhead reaches thevicinity of the fixing jig② Released from fixing jig(Toolhead rises)

5

Unlocked

Fixing jig
Bottom ofhoisting
equipment

Toggle mechanism forthe connecting guide pipe

Toolhead

Toolhead③ Toolhead reaches the end of drum winding<Conclusion>⇒ Confirmed the feasibility of operations in combination with each equipment.
©International Research Institute for Nuclear Decommissioning6. Implementation details

No.28(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results①-1 Abrasive feed rate stabilization study (structure review study)
Conventional abrasive
adjustment mechanism
Abrasive

Needle valve

Issues from FY2021 testing
Small gaps caused
unstable feed rate

Implementation details in FY2022
Orifice

Abrasive

PulleyRevolution

Unstable feed
rate occurred
Abrasive feed rate: 500 g/min- Needle valve opening adjusts
abrasive feed rate (free fall fromgap)

- Stable feed rate
- Feed rate is not
adjustable

Abrasive feed rate: 100 g/min- Feed rate was unstable in low abrasive feed
- The opening of the needle valve was small and it is believedthat the small gap destabilized passage of the abrasive- The design changed to an orifice and the feed rate stabilized⇒ Feed rate is determined by the hole diameter, so thefeed rate cannot be adjusted.

Abrasive feed rate: 100 g/min or more

- Adopts a method of transporting
abrasives via the rotation of a pulley- Feed rate can be adjusted bychanging rotation speed©International Research Institute for Nuclear Decommissioning6. Implementation details

No.29(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results①-2 Abrasive feed rate stabilization study (feed mechanism design)
From abrasive tankAbrasive
feed line

Buffer tankAbrasive
feed line[Main design details]
Design of the abrasive feed mechanism- Adopts a pulley type feed mechanism- Structure designed in response to low abrasive feedrate
- Size and layout designed to allow the feed mechanism
and buffer tank to fit inside the connecting guide pipe

PulleyAbrasive

Revolution
Abrasive feedmechanism

Abrasive
feed line
To nozzle

Abrasive feed mechanism external view

Illustration of pulley type feed mechanism©International Research Institute for Nuclear Decommissioning6. Implementation details

No.30(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results①-3 Abrasive feed rate stabilization study (Element prototype testing plan)

Test item
1. Abrasive feedmechanism
performanceverification

2. Simple evaluationof cutting
performance

Details and conditions to confirm

Measurement andconfirmation items

1.1 Feed mechanism functional verification- Confirm that the abrasive feed rate can be adjusted by adjusting pulleyrotation speed and that a stable feed rate can be achieved with only thefeed mechanism (without water jet injection).
[Test conditions]Set feed rate: 100 g/min
110 g/min
120 g/min
200 g/min, 500 g/min (reference)① Check the pulley rotation
speed for the set feed rate.
② Verify that a stable feed ispossible.

1.2 Performance check during water jetting- Based on the test results of 1.1 above, conduct a feed rate verification
test with a water jet to confirm that the set feed rate can be adjusted andthat a stable feed rate is possible.
[Test conditions]Set feed rate: 100 g/min
110 g/min
120 g/min
200 g/min, 500 g/min (reference)① Check the pulley rotation
speed for the set feed rate.
② Verify that a stable feed ispossible.
③ The difference with andwithout water jet

2.1 Flat plate cutting test
- Make cuts down the thick edge of a metal plate and evaluate
performance by comparing whether cut depth is equivalent to FY2021
cutting performance.
[Test conditions]- Flow rate: approx. 3 L/min- Pressure: 343 MPa- Cutting speed: 60 mm/min- Feed rate: 100 g/min- Standoff: 20/50 mm① The performance should beequivalent to the FY2021 flat
cutting performance.

©International Research Institute for Nuclear Decommissioning6. Implementation details

No.31(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results①-4 Abrasive feed rate stabilization study (abrasive feed mechanism performance testing)Abrasive tank

<Test results>

18 m
Simulated height ofactual equipment

Buffer tankAbrasive feedmechanism
Feed mechanism functionalverification testing measured
the amount of abrasive in thisline

Spiral shape (assuming actual
equipment)(Abrasive supply line, high-pressure
water supply line)

Nozzle*1: Listed feed rate is the average of three tests.
Feed mechanism functional verification test results (without water jet)No.

Set feed rate
(g/min)Pulley rpm(min-1)

Feed rate *1(g/min)

1
2
3

100
110
120

16
18.6
20.6

98.0
110.5
120.2

4

200

36.4

203.2

5

500

115.5

494.0

Remarks
Set value for actual equipment
Set value for actual equipment × 1.1
Set value for actual equipment × 1.2<Reference> Set value for actual
equipment × 2<Reference> Set value forconventional use⇒ ① Verified that feed rate can be controlled at 10 g/min pitch between 100 and
120 g/min by adjusting pulley rpm

Performance test results during water jet injectionNo.

Set feed rate
(g/min)Pulley rpm(min-1)

Feed rate *1(g/min)

1
2
3

100
110
120

16.4
18.9
20.7

100.0
112.8
122.6

4

200

36.6

211.1

5

500

115.5

499.4

Remarks
Set value for actual equipment
Set value for actual equipment × 1.1
Set value for actual equipment × 1.2<Reference> Set value for actual
equipment × 2<Reference> Set value forconventional use⇒ ① Verified that feed rate can be controlled at 10 g/min pitch between 100
and 120 g/min by adjusting pulley rpm, even with water jet injection

Abrasive feed mechanism functionalverification testing system©International Research Institute for Nuclear Decommissioning6. Implementation details

No.32(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results①-5 Abrasive feed rate stabilization study (simple evaluation of cutting performance)<Test conditions><Test results>

Thickness offlat plate test
piece: 10 mm

20/50 mm

FY2022 Results

1

20

6

2

20

6

3

20

6

Cutting marks
Cutting depth
evaluation

4

50

4

5

50

4

6

50

5

AWJ nozzle
Feed direction
stroke: 15 mm

Emission angle: 90°
Abrasive feed rate: 100 g/min

Cutting depth (mm)Standoff(mm)

No.

Standoff: 50 mm

74Standoff: 50 mm
Standoff: 20 mm

Flat-plate testpiece

FY2021 Results

Cutting plate after cutting test
(Standoff: 20, 50 mm) (front view)

Standoff: 20 mm

Cutting plate after cutting test
(Standoff: 20, 50 mm) (top view)Nozzle⇒ ① A simple evaluation test after a change to the abrasive feed mechanism
confirmed that cutting performance was equivalent to conventional
performance (FY2021 test results).
② This simple evaluation test contained only a few test parameters, so future
tests must be conducted on flat plates and structure mockups to verify that
Setup for simple evaluation test of cutting performance
performance is equivalent to that of the conventional feed mechanism.
©International Research Institute for Nuclear Decommissioning6. Implementation details

No.33(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results②-1 AWJ nozzle maintenance (organization of preconditions)

No.

Items

FY2019FY2022

1

Maintenance area

Area below the airlock cell (seefigure below)

Examination of areas provisionally assumed in FY2019, includingchanges.

2

Replacement
methodUnexamined

Examine either remote replacement or manned replacement with
exposure and contamination countermeasures.

3

Exchange target- Camera- Camera- Nozzle(FY2021 test results set nozzle life at about 8 hours. Operation time isabout 42 hours, however, so replacement is required.)Work cell

CameraAirlock cell side equipment
carry-in entrance

Work cell side equipment carry-in entrance

Airlock cellWork cell

Airlock cell side equipment
carry-in entrance

Angle nozzle

Airlock cell
Toolbox

CameraDrum
ToolheadRail

Airtight
shutter

Maintenance areas
considered in FY2019(provisional)

Move from work cell to airlock
cell during maintenance

Straight nozzle

Transport carrier

Airtight
shutter

Simplified diagram of work cell interior

CameraExchange target©International Research Institute for Nuclear Decommissioning6. Implementation details

No.34(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results②-2 AWJ nozzle maintenance (toolhead tip structure review)••

A flange part was added to allow for detachment and replacement of the nozzle part, which wears out due to AWJ injection, and thestructure affixes to the toolhead with bolts.
(See the figure below)
A connector and flange that can be remotely attached/detached were added to the base of the overhead/side-view camera, and thestructure affixes to the toolhead with bolts.

Drum

Bird’s eye
camera fixing
flange(Contains remoteconnector)

Nozzle fixing
flangeBird’seyecameraConnecting
guide pipe

Toolhead

Full equipment view

High-pressure
water supplyline

NozzlefixingflangeAbrasive
feed line

Angle
nozzleSide camera
fixing flange(Contains remoteconnector)

Flangefixing pin

SidecameraNozzle fixing
bolt × 2

Diagram of view
from arrow A

Arrow A
Toolhead tip (angle nozzle example)

Separated state (angle nozzle example)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.35(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results②-3 AWJ nozzle maintenance (functional verification testing plan for partial element prototypes)

Use a prototype of a partial element at the toolhead tip that can simulate the nozzle andbird’s eye camera flange structure and a prototype of a partial replacement jig toconfirm the feasibility of the replacement operation and to check the integrity of eachpart before and after replacement.
Items to be checked in the test are as follows.

Items and conditions to confirm
Verify replacement operation

Verify nozzle and camera integrity
before and after replacement① Check high-pressure water jet- Check the pressure of highpressure water (pump pressure)
Set pressure: 343 MPa② Check abrasive injection- Check abrasive feed rate
Set feed rate: 100 g/min③ Check camera image

Nozzlereplacement jig(Enlarged tip)
Positioning
guide (groove)

Assessment criteria
The nozzle and camera
must be able to attach anddetach.

Positioning
pin

Bird’s eye
camera fixing
flange① Reaches set pressure.

Bird’s eye
camera mockup
section② Capable of feeding within±10% of set feed rate.

Nozzle fixing
flange③ No issues with images.

Angle nozzle
mockup section
Flange structure is
identical to that of thebird’s eye camera, so
a mockup of a sideview camera is not
used.

Position andinsertreplacement jig
from below
Fixing bolt operating axis

Toolhead tip(Partial element prototype)Nozzle replacement
jig part prototype©International Research Institute for Nuclear Decommissioning6. Implementation details

No.36(1) Upgrading of processing technology for the top-access investigation method
6) AWJ cutting technology results②-4 AWJ nozzle maintenance (results of functional verification tests of partial element prototypes)
Nozzle fixing
flange<Test results>
Items and conditions to confirm

Verify replacement operation

Assessment
criteria

Results

The nozzle andcamera must be able
to attach and detach.

Satisfactory

Nozzle fixing
flangeAngle
nozzlemockupsection②

Verify nozzle and camera integrity
before and after replacement① Check high-pressure water jet- Check the pressure of highpressure water (pump pressure)
Set pressure: 343 MPa② Check abrasive injection- Check abrasive feed rate
Set feed rate: 100 g/min①① Reaches set
pressure.

Satisfactory①②② Capable of feeding
within ±10% of set
feed rate.

Satisfactory(+1%)③ No issues withimages.

Satisfactory

Nozzlereplacement
jig

Fixing bolt
operatingaxis

Nozzlereplacement
jig③ Check camera image⇒ The feasibility of the nozzle and camera with the flange structure wasverified, and so they will be reflected in future designs of actual equipment.
Replacement jigs must be designed for remote operation. (When informationon the actual equipment is input and maintenance area constraints are wellunderstood, expected to be TRL 5 or later.)

Replacement procedure(Installation procedure: blue,
Removal procedure: red)

Turn theoperation
shaft totighten or
When therelease thereplacement jig bolt

is attached©International Research Institute for Nuclear Decommissioning6. Implementation details

No.37(1) Upgrading of processing technology for the top-access investigation method
7) Results of common issues for laser & AWJ cutting technologies① Study of patterns of uncollectible connecting guide pipes
Cause of event(1) Interference
from anobstacle(Snagging)(2) Drum failure① Poor visibility or failure ofsurveillance cameras and/or lights
due to vapor, etc.

① Drive motor operation failure(Drum rotation / forward-backward/ horizontal axis)

Risk reduction measures

Response (including examination items)- Consider installing surveillance cameras that can monitor thearea from the boundary guide pipe to the steam dryer in
addition to the cameras mounted on the toolhead.
- Use the installed surveillance cameras and lights to checkvisibility conditions on the access route.

1) Attempt to remove the interference by moving the connecting guide pipe vertically.
2) If the issue remains unresolved, use an external crane to forcibly collect the connecting
guide pipe, drum, and other equipment. (When doing so, it is necessary to consider
covering the area with an elastic sheet to prevent contamination, high pressure water
decontamination, and other hazards.)- Verify operation prior to processing.

[If the drive motor is a heavy weight object]
1) Consider using two drive motors, so that the drum can operate even if one of the motors
fails.
2) If the issue remains unresolved, use an external crane to forcibly collect the connecting
guide pipe, drum, and other equipment. (When doing so, it is necessary to consider
covering the area with an elastic sheet to prevent contamination, high pressure water
decontamination, and other hazards.)[If the drive motor is a light weight object (can be carried by hands)]
1) Manually replace with the spare drive motor and collect the connecting guide pipe using
regular operations.

① Defective hoisting operation(hoisting drive roller)(3) Hoisting
equipment
failure② Toggle unlock mechanism /detection mechanism operation
failure- Verify operation prior to processing.

1) Collect the connecting guide pipe by simply rotating the drum while monitoring thewinding condition.

- Use the surveillance camera to check the unlock operation andunlock detection prior to processing.

1) Use surveillance cameras to confirm whether toggle unlocking is enabled or disabled
and whether it is detected.
2) If the unlocking mechanism is inoperative, restart the drive source to confirm that it isback in operation.
3) If the unlock detection mechanism is inoperative, collect the connecting guide pipe while
using a surveillance camera to check whether unlocking is possible.
4) If the toggle unlock mechanism is inoperative, have someone enter the toolbox to collectthe connecting guide pipe while manually operating the toggle unlock.
1) Release the pressure on the guide pipe by releasing the water pressure in the clamp
cylinder to free the cylinder, and collect the connecting guide pipe.
2) Collect the connecting guide pipe and then collect the fixing jig.

① Guide pipe clamp operation failure(4) Fixing jig
failure(5) Toolhead
operation
failure- Verify operation prior to processing.
② An object catches on the fixing jig(except for defective clamp
operation)

1) Release the jig clamp and remove the connecting guide pipe. Leave the fixing jig as is.

① Malfunction at maximum operation - Check shaft operation before collecting the connecting guideof α-axis or R-axis
pipe.

1) It is necessary to consider an axis that allows joints to become free and collectible whenthe α- and R-axes interfere with the fixing jig during connecting guide pipe collection.

② Backward reaction force receiver
operation failure- Taper the shape of the backward reaction force receiver.
Consider this design so that even if the reaction receiver push
operation fails, the guide pipe can be lifted and lowered toallow the reaction receiver to slide and be collected without
snagging, even if it interferes with other equipment.

－

Note: The necessary spare parts for all matters should be prepared ahead of time.

©International Research Institute for Nuclear Decommissioning6. Implementation details

No.38(1) Upgrading of processing technology for the top-access investigation method
8) Summary① Results obtained in FY2022[Common (Laser & AWJ cutting)]- Issues and countermeasures for each processing technology were examined based on results obtained throughFY2021, and a development plan was formulated.
[Laser cutting]- The specifications of the laser cutting device (prototype) were studied, and a prototype was designed andmanufactured.
- The functional verification of the laser cutting device (prototype) was tested, and its functional verification wasdeemed to be satisfactory.

[AWJ cutting]- The composition was reviewed to stabilize the abrasive feed rate and a prototype of this sub-element was
designed and manufactured.
- A partial element prototype of a toolhead tip that allows for remote replacement of the nozzle and camera wasdesigned and manufactured.
- Functional verification tests were conducted for each component prototype and their functional verification wasdeemed to be satisfactory.

② Issues to be addressed (FY2023 and beyond)Laser cutting equipment(prototype)

Processing
technology

No.(*)

Issues to be addressed

Processing
technology

No.(*)

Laser

1

Feasibility of the remote equipment
considering actual equipment(Prototype machine cutting performance)

AWJ

7

Abrasive feed rate stabilization (partial element prototype cutting
performance)

8

Nozzle maintenance (design and manufacture of actual equipment, etc.)

2

Nozzle maintenance3

Effect of dross on cutting

10

Treatment of cut pieces (transfer)

4

Influence of the actual operating
environment(Temperature, humidity, and atmosphericconditions)11

Radiation resistance of components

12

Durability of components

Assist gas restrictions (type and flow rate)

13

Installation method in case of damaged and deformed reactor internals

14

Responses to uncollectible connecting guide pipes

5

CommonIssues to be addressed(*): The Issue No. corresponds to the list of development issues on slides 11 to 13.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.39<Implementation details up to FY2021>
For investigations into the reactor pressure vessel (RPV) interior, the necessity of investigation via bottom access was verified, existing
technologies that have been developed or are currently in development in other subsidy projects were reviewed, and the applicability ofaccess technologies for each unit was evaluated. Investigations for Unit 1 were narrowed down to a use of a drone (wired/wireless).
Simplified testing and element testing were conducted to evaluate the feasibility of the selected technologies.

<Summary of implementation in FY2022>① Formulation of a bottom access investigation plan and development plan for investigation equipment
Develop an investigation plan that incorporates access equipment under development in other projects and formulate a development
plan for investigation equipment.
② Test manufacturing of bottom access and investigation equipment, functional verification testing
Design and manufacture prototypes and confirm that unit functions are satisfactory.

<Implementation details for FY2022>
Implementation details①

Study countermeasures to investigation issues②

Examine and draft an investigation plan and development plan③

Specification study/design and manufacturing of investigation equipment considering actual
equipment④

Confirmation of performance of the functions by functional verification tests<Results>- Based on results up to FY2021, issues were identified and countermeasures were examined.
- The investigation plan and development plan were reviewed with consideration to customizing access equipment under development inother projects and incorporating them into plans.
- The specifications of each device were studied, and devices were designed and manufactured. Functional verification tests were also
conducted on these devices to evaluate their performance of the functions.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1No.40

1). Results as of FY2021 (1/2)
For investigations into the reactor pressure vessel (RPV) interior, the necessity of investigation via bottom access was verified, existing
technologies that have been developed or are currently in development in other subsidy projects were reviewed, and the applicability ofaccess technologies for each unit was evaluated. Investigations for Unit 1 were narrowed down to a use of a drone (wired/wireless).
Simplified testing and element testing were conducted to evaluate the feasibility of the selected technologies.
Implementation details and results
1. Narrowing down access technologies based on investigation demands
Investigation demands Obtain image data and dose rate

Assumed RPV opening(diameter: about 1 m)

CRD opening

Access technology The access technology for Unit 1 was narrowed down to the use of a drone (wired/wireless).

- Drone (wired/wireless)- Crawler type accessequipment
F
l
i
g
Drone
h
t Bottom of RPVAssumed RPV opening

Diameter: approx. 5 m

r
o
u
t
e

Pedestal

X-2 Pene
Access route

Crawler
type*1accessequipment

CRD
Opening

Cable drum

Telescopic rod

Guide pipe

Access route overview (X-2 Penetration (Pene) to CRD opening)

Approx. 5.8 m

RPV

Grating*1: Assumed
applications
include cable feed
for wired drones
and radio relay for
wireless drones.

Access route overview (CRD opening to RPV interior bottom)©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.41

1). Results as of FY2021 (2/2)
For investigations into the reactor pressure vessel (RPV) interior, the necessity of investigation via bottom access was verified, existing
technologies that have been developed or are currently in development in other subsidy projects were reviewed, and the applicability ofaccess technologies for each unit was evaluated. Investigations for Unit 1 were narrowed down to a use of a drone (wired/wireless).
Simplified testing and element testing were conducted to evaluate the feasibility of the selected technologies.
Implementation details and results
2. Conduct simplified tests and element tests

Top of RPV
opening(height: 7000 mm)

Water drop
jig

Wired drone:- Improved flight performance→ Achieved target flight height of 7 m.
- Improved investigation performance
Rainfall (dripping
RPV interior (investigation→ Verified that investigation is possible in dark/rainywater) simulationarea) simulation
environments by panning and tilting the camera.
Wireless drone:- Improved flight performance
Bottom of RPV→ Continuous flight time of about 6 minutes is
opening(height: 2500 mm)
possible.
- Improved investigation performance
Simulated RPV opening→ Verified that investigation is possible in dark/rainy Mockup equipment exterior view
12.8 menvironments by panning and tilting the camera.
Control
CRD opening room
Outlet ofTIP guide- Communications check
the CRD
pipe
opening→ Based on tests and analyses, prospects ofcommunication with the actual equipment are
Inlet of theCRD
favorable.
opening
Ancillary system:- Cable drum
1.8 m
8.1 m
In front of the CRD opening /CRD opening / TIP→ Verified electrified cable drum performance.
Simulated control room
guide pipe mockup- Bird’s eye camera
FY2021 test facility exterior view
→ Bird’s eye camera monitored drones in flight toimprove maneuverability.

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.42

2). Development flow
FY2021 results (issues)

FY2022

TargetExample content/result
Element testing
Overallmethod① Identify advantages,
disadvantages, and issues for both
wired and wireless drones

Element testing
Wired andwirelessdrones /accessequipment① Heat generated by interior parts[wired]② Insufficient reserve flight time
[wireless]③ Cable drum feeding failure

Element testing① Insufficient radiation resistanceof some onboard electronic
components

Individual
issues(Example)② Drones can pass through an
opening of □800 while contacting
the frame [wired/wireless]③ Lack of extra payload makes it
difficult to use small dosimetersdeveloped in other PJs in wirelessdrones [wireless]

Desk study / Prototype design and manufacturing
Review of investigation
plan

Test

Formulation of proposeddevelopment plan

① Review investigation proceduresfor wired and wireless drones② Case studies for the investigation
plan③ Reconfirm issues

Re-examination of existingproducts and technologies① Establish evaluation items andtarget goals for the method② Examine the outline and test items
of FY2022 functionality verificationtests③ Formulate a draft development
plan for FY2022 and beyond
Equipment design andprototyping① Research electronic componentsthat generate little heat② Reevaluate mounted cameras③ Examine the applicability ofequipment developed in other PJ(access equipment and cableassistance devices)① Re-organize assumptions, design
conditions, and required specifications② Design equipment for actual
equipment (initial design)③ Research lightweight high-capacity
batteries④ Evaluate and review improvementsof equipment developed in other PJs

Re-examination of existingproducts and technologies

Study of electronic
components① Newly design and prototype
electronic components whencommercial products do not exist① Research flight controllers
without products that causeradiation resistance degradation

Review of operation andcontrol methods

Study of control methods① Examine control methods that
can improve in-flight stability② Investigate the need to improve
operability
Re-examination of existingproducts and technologies① Research lightweight dosimetersthat can be mounted on wirelessdrones

① Consider whether to implement thedrone being developed② Study improvements to increase
operability
Development of dosimeters① Newly design and manufacture
dosimeters when commercial
products do not exist

FY2023 (*)

FY2024 and later (*)

Examination of
applicability to actual
equipment/ combined test

Preparation for application toactual equipment

Formulation of development
plan for actual equipment－(FY2022 is scheduled tofocus on verifying
performance of thefunctions)

Functionality
verification testing① Confirm the possibility ofachieving required
specifications (projected)② Identify points for
improvement for FY2023
and beyond

Functionality
verification testing① Conduct irradiation tests
to verify radiation resistance
Functionality
verification testing① Confirm the degree of
improvement in in-flightstability
Functionality
verification testing① Check whether therequired functions can beachieved① Review the development planas necessary, reflecting
equipment design and test results② Examine risk response
scenarios such as recovering froma crash, the collection method if
an object becomes stuck, andmeasures to take in the event ofcontamination③ Formulate an investigation plan
for actual equipment

Manufacturing
equipment forinvestigations ofactual equipment
Work
verification

Feedback

Mockup testing

Detailing ofwork
procedures andinvestigation
process

Equipment improvements &combined testing① Reflect the results of eachfunctionality verification test in
designs of devices for the actual
equipment② Conduct combined tests

Preparation of mockups① Create a mockup verificationplan② Draft a basic design of mockup
equipment

Work
training

ReviewUsing actual
equipment
Evaluation of items assumed in actual
equipment and reflection in procedures- Route for investigation- Investigation performance (camera visibility)- Flight time, flight performance (including
operational performance)- Prospect of obtaining information- Performance assessment of peripheral
equipment such as telescopic rods, cabledrums, cable supports, etc.

Plans for FY2023 and beyond are proposals from the project implementer and have not been decided.
©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.433). Development issues and action policies (1/3)
No.

Major items

Overall
investigation
1 method23Intermediate
items

―

Equipment for Telescopic
accessing the rod
inside of thepedestal

Development issues

Action policy (plan)

Conducted
or not in
FY2022

FY2022 test/action items

Corresponding
slide No.

Feasibility of the investigation
method series (including accessfrom X-2 Pene to CRD opening)

Based on FY2021 test results, the- Gather information from other projects
investigation method series will be studied- Desk study
when using wired/wireless drones andNo.46 to 48
Conducted
ancillary equipment (including products
developed in other projects).
Cable pinching during rod
Encase the cable inside the telescopic rod.
Reflect in prototype design and conduct
No.54
Conducted
retraction(Lateral development from other projects)
functional verification tests
Radiation resistance of electronic Order the applicable conditions (air dose rate―
(To be conducted in FY2023 or later because it cancomponents
and investigation time) and conduct irradiation―refer to development results of surveys of pedestal
testing to confirm the radiation resistance of―interior and the payload constraints of the(None)
electronic components.
equipment are small, so shielding measures, etc.
are easy to adopt)

Equipment durability
4

5

6

7

Cable drum Improved cable feed
(wired drone) - Event of cable feeding to theback of the drum
- Cable feed roller idling- Unable to verify feed rate
Treatment of cable drum drive
cable

Conduct continuous operation tests in anenvironment simulating actual operating
conditions to confirm durability.

――(None)(To be conducted in FY2023 or later, as it wasdeemed reasonable to check with equivalentequipment after the design of the actual equipment
is decided)- Review of cable drum structure and function
Reflect in prototype design and conduct- Study of the feed rate verification method
functional verification tests(additional cameras, etc.)
Conducted

Examine devices that can assist the driving- Desk study
cable.
- Gather information from other projects(Including consideration of the applicability of Conducted - Reflect findings in prototype design andthe cable assistance device being developed
conduct functional verification testingin the investigation inside the pedestal)
Radiation resistance of electronic Order the applicable conditions (air dose rate―
(To be conducted in FY2023 or later because it will
components
and investigation time) and conduct irradiation―
travel outside the pedestal, where the dose rate is
testing to confirm the radiation resistance ofrelatively low (approximately 10 Sv/h), and the(None)
electronic components.

―

No.55

No.56

―

payload constraints of the equipment are small, soshielding measures, etc. are easy to adopt)

Equipment durability
8

Conduct continuous operation tests in anenvironment simulating actual operating
conditions to confirm durability.

――(None)(To be conducted in FY2023 or later, as it wasdeemed reasonable to check with equivalentequipment after the design of the actual equipment
is decided)―©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.443). Development issues and action policies (2/3)
No.

Major items

Intermediate
items

Development issues

AccessCommon toDrone miniaturizationequipment
wired/wireless
9 from inside the drones
pedestal toinside the
Flight control
10 RPV
11

12

13

14

Water droplets on
camera lensAction policy (plan)
Conduct case studies on miniaturization.
(Also examine miniaturization by reducing thenumber of on-board components)

Conducted or
not inFY2022
Conducted

Review of control methods

FY2022 test/action items- Desk study- Reflect findings in prototype design andconduct functional verification testing

No.49

Desk study
No.70

Conducted
Examine measures such as applying lenscoatings.

Corresponding
slide No.

Reflect in prototype design and conduct
Conducted functional verification tests

Landing position
Examine measures such as adding lighting toReflect in prototype design and conduct
confirmation
ancillary equipment.
functional verification tests(FY2021 once-throughtests in dark
Conducted
environments
experienced visibility
issues with landing
position)
Radiation resistance of - Research new flight controllers (because- Review of flight controller
electronic components
FY2021 irradiation tests determined that the- Irradiation testing
compass sensor was unusable)- Organize the applicable conditions (air dose rateand survey time) and conduct irradiation testing Conductedin an energized state to verify the radiation
resistance of electronic components and theimpact on operation. (including confirmation of
the impact on camera images)
Equipment durability
Conduct continuous operation tests in an―(To be conducted in FY2023 or later, as it wasenvironment simulating actual operating―
deemed reasonable to check with equivalentconditions to confirm durability.
(None)
equipment after the design of the actual

No.50 and 52

No.54 and 55

No.51 and 53
No.80 and 81
No.86 to 88―

equipment is decided)

Increasing flight altitude Testing will verify whether the drones can fly
limit
above 11 m (core support plate height).
15(FY2021 tests confirmed the feasibility of the 7 m target
flight height required for investigations, so the response
is set to HOLD. The need for a response will bereconfirmed based on the results of responses to otherprojects and other issues)―(None)―(HOLD)―©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.45

3). Development issues and action policies (3/3)
No.

Major items

Intermediate
items

AccessWired drone
equipment
16 from inside thepedestal toinside the
RPV
17
Wireless drone
18

Development issues
Heat generation ofelectronic components

Research orconsideration oflightweight radiation
sensors that can bemountedExtending flight time

Conducted

Conducted

Consider small and lightweight radiation
sensors.

FY2022 test/action items
Reflect in prototype design and conduct
functional verification tests

Reflect in prototype design and conduct
functional verification tests- Consider reviewing the battery.
- Study measures to reduce power consumption

Extract risks and study countermeasures, thenreflect them in the design.

Contamination ofcomponents

Extract risks and study countermeasures, thenreflect them in the design.

No.50

No.50

No.52

Conducted

Drone crash impact
assessment

Corresponding
slide No.

- Desk study- Prototyping of element technologies- Desk study- Prototyping of element technologies
No.52

Installation
Feasibility of X-2 Pene Determine if installation equipment for- Desk study
equipment for the passage via installation investigations inside the pedestal can be- Prototyping of element technologies
PCV
equipment used in other diverted. If it cannot, organize changes to make. Conducted
projects
Risk response

22

Conducted or
not inFY2022(Although FY2021 tests showed that the flight timerequired for the survey was achievable, studies will be Conducted
continued in consideration of combination withancillary equipment and providing reserve flight time.)

Others21

Examine measures such as reviewing theinternal structure and adding heat sinks, aircooling fans, or other components.

Inclusion of the drone in Consider reviewing the structure.
the investigation images

19

20

Action policy (plan)

No.57 to 60

Desk study
No.69

Conducted――(None)(To be conducted in FY2023 or later, as it wasdeemed reasonable to prioritize studies ofequipment designs for which a survey can be
conducted)―©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.46

4). FY2022 implementation details ① Revision of investigation plan
- From the results of the case studies below, the following operations were determined to be highly feasible for investigations using wired andwireless drones.
1. A wired drone with ample flight time will verify damage and the flight path for the following wireless drone.
If possible, it will also investigate the bottom of the RPV interior (approximately 7 m above the platform inside the pedestal) and then return.
2. A wireless drone will investigate the area near the top of the core support plate (approximately 11 m above the platform inside thepedestal), as wired drones cannot investigate this area.
- FY2022 prototypes will have on-board equipment and body configurations according to the respective roles of wired and wireless drones.
No.

Investigationcase

Investigationequipment
configuration
Wired
Wireless
drone
drone

Investigation procedure

Drone-mounted
investigation equipment (*1)

Single wired
drone

2

Single wirelessdrone

1 unit-- Steering/
investigation
camera- Dosimeter-1 unitDisadvantages

Investigation
Components
equipment
Investigation of the bottom of the RPV Wired drone
interior (altitude approx. 7 m) with asingle wired drone

1

Advantages

Investigation of the bottom of the RPV Wireless drone - Steering/interior (altitude approx. 7 m) with ainvestigation
single wireless drone
camera- Dosimeter

1. The wireless drone A checks fordamage, verifies the flight path forthe following drone B, and thenreturns
2 units (*1) 2. Wireless drone B investigates thebottom of the RPV interior (altitude
approx. 7 m)

- Long flight (investigation) times are
possible- Stable communication(steering/video)- Limited flight freedom/altitude(FY2021 test results: maximum
flight height of 8 m).
- If the bottom of the RPV interior
cannot be accessed vertically,
there is a risk that increasing the
tow cable length would prevent thedrone from reaching theinvestigation location.
Ample flight freedom and altitude- Short flight duration (FY2021 test
results: approx. 6 minutes)- Video noise (from multipath)- Risk of wireless communication
failure- Wireless drones A/B have the same - Wireless drones A/B have theadvantages listed in No.2
same disadvantages listed in No.2
- Wireless drone A can have extended - Short flight time may prevent
flight time (due to reduced aircraft
adequate investigation
weight)- Wireless drone A will check the flightroute, so the flight time of wirelessdrone B can be shortened- The wired drone has the same
The wired drone has the sameadvantages listed in No.1 and thedisadvantages listed in No.1 and thewireless drone has the same aswireless drone has the same as
those listed in No.2
those listed in No.2
- The wired drone can scout the flightroute of the wireless drone, reducing
flight time for the wireless drone- There are prospects for obtaining
additional information on the upper
section of the RPV interior

Wireless drone - SteeringAcamera(preliminary
investigation)
Multiple wireless3
Wireless drone - Steering/dronesB
investigation(investigation)
camera- Dosimeter
1. The wired drone will check for
Wired drone- Steering/damage and verify the flight path for (preliminary
investigation
the following wireless drone. If
investigation)
camerapossible, it will investigative the- Dosimeter
Combination ofbottom of the RPV interior (height
Wireless drone - Steering/
wired
approx. 7 m) and then return4
1 unit1 unit (*1)(investigation)
investigation
drone/wireless
2. The wireless drone will investigate
cameradrone
from the bottom of the RPV interior- Dosimeter(altitude: approx. 7 m) to the top of
the interior (top of the core support
plate) (height approx. 11 m)(*1) The number of units, investigation procedures, and the configuration of drone-mounted investigation equipment will be reviewed as necessary depending on the
progress of the study.
(*2) Feasibility of investigation when the drone is not equipped with a dosimeter and used solely to obtain images. A wired drone will not require a dosimeter cable,
reducing the weight of the composite cable and increasing flight altitude. The mass of the wireless drone can be reduced by the mass of the dosimeter, thereby
extending flight time.

Feasibility for
Feasibility for investigation (*2)
investigation(Imageacquisition only)

△

○

×

×

△

△

○

◎

Investigation feasibility legend:◎: Highly feasible, may be able to obtain additional information○: Highly feasible△: Some parts may not be feasible
×: Low feasibility©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.47

4). FY2022 implementation details ② Overall investigation system configuration (1/2)

Category

Wired drone investigation system

Wireless drone investigation system

Wired drone / Telescopic rod transfer cart / Cable drum transfer cart / Cable
Equipment
assistance device / Installation equipment / Other devices (surveillance
configuration
cameras, etc.)
Wired drone(investigationequipment)

Outline(afterinstallation)

Telescopic rodtransfer cart for
wired drone

Wireless drone / Telescopic rod transfer cart / Cable assistance device /Installation equipment / Other devices (surveillance cameras, etc.)
Wireless drone(investigationequipment)

CableassistancedeviceCableassistancedeviceCable drumtransfer cart

Bird’s-eye
view

Front view
(entire device)

Telescopic rodtransfer cart for
wireless drone

Bird’s-eye
view

Front view
(entire device)

Wireless drone
Wired drone
Telescopic rod transfer
cart

Telescopic rod transfer
cart

Bird’s-eye
view(afterinstallation)

Cable drum transfer cart
Device legend

Device legend: Wired drone: Telescopic rod: Cable drum
: Cable assistance device: Wired drone: Telescopic rod: Cable assistance device

Cable assistancedeviceCable assistancedeviceCable legend: For wired drone: For telescopic rod: For cable drum
: For cable assistancedevice

Cable legend: For telescopic rod: For cable assistancedevice©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.48

4). FY2022 implementation details ② Overall investigation system configuration (2/2)

Common to wired & wirelessEquipment overview

Test-manufactured or not in FY2022

Wired drone• Installs through the 350A opening of the X-2 Pene, flies over the platform outside the pedestal, enters thepedestal through the CRD opening, and accesses the RPV interior through the anticipated opening at thebottom of the RPV.
• Investigates (obtains video and measures dose rate) the bottom of the RPV (about 7 m from the CRD
replacement platform) while towing the composite cable that is fed from the tip of the telescopic rod.

Telescopic rodtransfer cart for
wired drone• Once the wired drone is installed, installs in the PCV through the 350A opening of the X-2 Pene andtravels over the remaining B1 investigation equipment to the front of the CRD opening.
• Extends the telescopic rod from the CRD opening to near the bottom of the anticipated opening on thebottom of the RPV inside the pedestal.
• The rod tip contains a mechanism that can feed and wind the composite cable from the wired drone.

Cable drumtransfer cart

• After the telescopic rod transfer cart is installed, installs through the 350A opening of the X-2 Pene andtravels over the remaining B1 investigation equipment to the front of the telescopic rod transfer cart.
• The cable drum winds the composite cable on the wired drone and contains a mechanism that can feed
and wind the cable. The composite cable on the wired drone runs along the telescopic rod on thetelescopic rod transfer cart and connects to the wired drone via the cable feed/wind mechanism at the tipof the rod.

Wireless drone• Installs through the 350A opening of the X-2 Pene, flies over the platform outside the pedestal, enters thepedestal through the CRD opening, and accesses the RPV interior through the anticipated opening at thebottom of the RPV.
• Investigates (obtains video and measures dose rate) the upper surface of the core support plate (about 11
m from the CRD replacement platform) while communicating wirelessly with the wireless equipment at the
tip of the telescopic rod.

Telescopic rodtransfer cart for
wireless drone• Once the wireless drone is installed, installs in the PCV through the 350A opening of the X-2 Pene andtravels over the remaining B1 investigation equipment to the front of the CRD opening.
• Extends the telescopic rod from the CRD opening to near the bottom of the anticipated opening on thebottom of the RPV inside the pedestal.
• The rod tip contains a transceiver for wireless communication with the wireless drone.

Manufactured

Cable
assistancedeviceInstalls from the 250A opening of the X-2 Pene, and uses the cable assistance mechanism to assist andmove the composite cable from either the telescopic rod transfer cart or the cable drum transfer cart installedon the platform outside the pedestal within the area up to the front of the remaining B1 investigationequipment in order to prevent snagging and other issues.

Manufactured

This device installs equipment inside the PCV from existing X-2 Pene guide pipes.

Manufactured

Wireless

Wired

Category

Installationequipment

Other auxiliarymachines

Improvements from the FY2021
prototype

Manufactured

No.49 to 51

Partial improvements from otherproject equipment*

Manufactured

Manufactured

No.54• Improvements to the cable
drum from the FY2021
prototype• Partial improvements to thedrive function from other projectequipment*

No.55

Improvements from the FY2021
prototype

No.40,
52 and 53

Manufactured

Partial improvements from otherproject equipment*(Partial
prototype)Installs in the X-2 Pene opening to assist during installation and uninstallation. (Assumes surveillancecameras for installation and uninstallation, equipment dose rate measurement and cleaning devices foruninstallation, and equipment for cutting the composite cable in the event of an emergency (auxiliarymachines shall be reviewed accordingly based on the results of future studies)).

Slide No.
describing
prototype

No.54

Partial improvements from otherproject equipment*

Partial improvements from otherprojects devices*, element
prototype for 350A only

No.56

No.57 to 60

No FY2022 prototype－－*Development of Technology for Detailed Investigation inside PCV©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.49

4). FY2022 implementation details ③ FY2022 prototypes (wired/wireless drone miniaturization)• Reduction in the size of both wired and wireless FY2021 prototype drones by reviewing parts and their configuration on the devices• The wireless drone was designed to investigate areas that the wired drone cannot reach (assumed to be the upper inside area of the RPV
and wall surfaces), so its size was reduced by eliminating the pan/tilt function of the camera on the bottom of the drone and placing thebattery and dosimeter in the vacant space.

Items improved from FY2021
No. *19Development issues
extracted from FY2021
results

Details of FY2022 countermeasures
Reviewed component layout and configuration,
miniaturized

Drone miniaturization*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.
Lower camera
Pan: ±180°
Tilt: 0 to -90°

270 mm

320 mm

270 mm

370 mm

450 mmAppearance of the lower part of the FY2022 wired drone

270 mmLower
cameraNo pan or tilt

Batterycase
Mockdosimeter

Appearance of the lower part of the FY2022 wireless drone
FY2021 wireless drone
FY2022 wired drone(wired drone has the same shape)

FY2022 wireless drone

Drone miniaturization (compared to FY2021 drone prototype)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.50

Unit 1(2) Development of the bottom access investigation method (drone)4). FY2022 implementation details ③ FY2022 prototype (wired drone (1/2)) Installation equipment dimension constraint: Φ290 mm
Items improved from FY2021
1 degree of freedom (front/back)Details of FY2022 countermeasures

11

Water droplets on camera lens Hydrophilic coating on camera lens12

Landing position confirmation

13

16
17

Radiation resistance ofelectronic components
Heat generation of electronic
components
Inclusion of the drone in theinvestigation images

Connector
case

Addition of LED lights to mark the landing position on thetelescopic rod transfer cart and cable drum transfer cart (seeNo.54 and 55)• Installation of a flight controller that does not have acompass sensor• Cameras were selected and mounted based on irradiation
tests (see slides No.80 and 81)

Composite
cable

370 mmNo. *1Development issues
extracted from FY2021
results

Added air cooling fan

Reviewed the design of cable connections

Simulated dosimeter
mass set to 40 g

Caseinterior

Power connector
Communication
connector

Composite
cable retaining
clampPower/communication
cables

*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.

270 mm

FY2022 prototype drawing

Upper camera
Tilt: 0 to 90°

Composite cable for
wired drone *2

Lower
camera pan:±180°
Tilt: 0 to -90°

External view of FY2022 prototype

Air coolingfan

Inside the FY2022 prototype*2 Dosimeter optical fiber (0.04 g/m) is not installed.
PEEK tube for protection is installed.

During horizontal flight©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.514). FY2022 implementation details ③ FY2022 prototype (wired drone (2/2))
Configuration of drone body interior

FY2022 wired drone: Power flow
: Communication flow

DC-DC converter[Propeller motor]
iFlight XING-E 2208 2450KV[Propeller motor]
iFlight XING-E 2208 2450KV[Propeller motor]
iFlight XING-E 2208 2450KV[Propeller motor][Steering motor (tilt)]
Z3675HV mini servo[Steering lighting][Air intake coolingfan][Distribution board &regulator]
MATEK MINIPOWER HUB 12V,5V[Air intake coolingfan][Regulator]
VKLSVAN LM2596[Gimbal controller]
STORM32[Power module]
HV PM (High voltage power module)

View of the added DC-DC converter
Insufficient power output prevented thedrone from flying at the target height (7 m)during preliminary confirmation testing, so
one DC-DC converter was added toincrease output capacity from 1200 W to1500 W as a countermeasure.

[Dedicated circuit board][Dedicated circuit board][Dedicated circuit board][Dedicated circuit board][Dedicated circuit board][Variable resistor][Variable resistor][Variable resistor][Variable resistor][Variable resistor][Tilt motor for investigation]
T-MOTOR GB2208[DC-DC converter]
53 V specifications
53 V → 20 V

[DC-DC converter]
53 V specifications
53 V → 20 V

[DC-DC converter]
53 V specifications
53 V → 20 V

[DC-DC converter]
53 V specifications
53 V → 20 V

[DC-DC converter]
53 V specifications
53 V → 20 V

[Pan motor for investigation]
T-MOTOR GB2208[Electrolytic capacitor][Electrolytic capacitor][Electrolytic capacitor][Electrolytic capacitor][Electrolytic capacitor][Lighting for investigation][SBUS-PWM]
SBUS-PWM converter[Flight controller]
Japan Aviation Electronics
Industry, Ltd.

[Manufactured-in
sensors]
Gyro sensor
Compass sensor (not[RS485 converter]
For converting telemetry
signals[RS485 converter][Steering camera]
DATASYSTEM
BIC263[Steering camera]
DATASYSTEM
BIC263used)[Connector]
JST-SM 10PIN[Connector]
AMASS XT60

[Safety switch][Composite cable: 15 m][Cable drum][Power source]
60 V / 30 A

Flight controller appearance
FY2021 irradiation testing revealed that thecompass sensor in the flight controller was
defective, so a flight controller without
compass sensor was installed.

[Connector]
JST-SM 10PIN[Connector][Camera swivel controller
for investigations][Drone operation system
controller][Computer for telemetry
display][Camera monitor 1][Camera monitor 2]

Overview of configuration of FY2022 wired drone prototype©International Research Institute for Nuclear Decommissioning6. Implementation details

No.52

Unit 1(2) Development of the bottom access investigation method (drone)4). FY2022 implementation details ③ FY2022 prototype (wireless drone (1/2)) Installation equipment dimension
constraint: Φ290 mm

Items improved from FY2021

Flight controller
Battery case

Details of FY2022 countermeasures

11

Water droplets on camera lens Hydrophilic coating on camera lens12

Landing position confirmation

13

Radiation resistance ofelectronic components

18

Research or consideration oflightweight radiation sensors
that can be mounted

19

Extending flight time

Addition of LED lights to mark the landing position on thetelescopic rod transfer cart and cable drum transfer cart (seeNo.54 and 55)• Installation of a flight controller that does not have acompass sensor• Cameras were selected and mounted based on irradiation
tests (see slides No.80 and 81)
Compact and lightweight radiation sensor in development••

320 mmNo. *1Development issues
extracted from FY2021
results

Elemental prototyping of in-house batteries
Equipped on wireless drones for energy efficient imaging(revised from 1 W to 0.01 W)*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.

270 mmAppearance of compact dosimeter (pulse measurement type) *2

Items

Upper camera
Tilt: 0 to 90°

Mock dosimeter(Case simulates the outside dimensions of acompact dosimeter prototype currently indevelopment. Mass adjusted to 200 g)

FY2022 prototype drawing
Appearance of in-house battery element prototype

FY2022 prototype
Items

In-house battery (indevelopment)

Regular battery

46 × 60 × 53 mm
6000 mAh (design value)
298 g (measured value)

44 × 135 × 30 mm
4600 mAh
385 g

Appearance
Appearance

Lower camera
No pan or tilt

Batterycase

Size

165 × 80 × 35 mm (excluding
antenna)Mockdosimeter

Weight

367 g (body: 280 g, batteries (4 pcs.):
96 g)

External view of FY2022 prototype*2 The feasibility of a COMS type dosimeter employing a different method isbeing studied alongside development of the pulse measurement type. The
target development weight for the next and subsequent years is 200 g or less.

Size
Capacity
Weight©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.53

4). FY2022 implementation details ③ FY2022 prototype (wireless drone (2/2))

Configuration of drone
body interior[Propeller motor]
iFlight XING-E 2208 2450KV[Propeller motor]
iFlight XING-E 2208 2450KV[Propeller motor]
iFlight XING-E 2208 2450KV[Propeller motor][Camera swivel motor(tilt)] Z3675HV mini servo[Lighting][Steering camera]
DATASYSTEM
BIC263[Video transmitter]
HN10T[Steering system receiver]FRSKY XM+(D16)[Air intake cooling fan][Air intake cooling fan]

[Flight controller]
Japan Aviation Electronics
Industry, Ltd.

Flight controller appearance
FY2021 irradiation testing
revealed that the compass
sensor in the flight controller was
defective, so a flight controller
without compass sensor was
installed.

[Lighting][Power module]
HV PM (High voltage power module)[Manufactured-in
sensors]
Gyro sensor
Compass sensor (not[Backflow prevention diode]Thu’s Radio 45V 30A

Output of the video
system transmitter was
revised from 1 W(installed in FY2021) to
0.01 W.
(To reduce standby
power, size, and weight.)[Distribution board & regulator]
MATEK MINIPOWER HUB 12V,5V[Backflow prevention diode]
Vishay 100V 100A

[Regulator]
VKLSVAN LM2596[Investigation camera]
DATASYSTEM BIC263[Video transmitter]
HN10T

used)

[Telemetrytransmitter]
XBEE3

Frequency
band 2.4 GHz[Telemetry receiver]
XBEE3[Safety switch]
CUAV SAFETY[Battery]
Rated voltage: 14.8 V
Current: 4600 mAh
C-rate: 35 C

Frequency
band 2.4 GHz[Steering systemtransmitter]
RADIO MASTER TX16S[Battery]
Rated voltage: 14.8 V
Current: 4600 mAh
C-rate: 35 C

Frequency
band 5.7 GHz[External power supply]
Rated voltage: 18 V

[Video receiver][Video receiver][Camera monitor 2][Camera monitor 1]

Frequency
band 5.7 GHz

Overview of FY2022 wireless drone prototype configuration©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.54

4). FY2022 implementation details ③ FY2022 prototype (Telescopic rod transfer cart for wired/wireless drone)
Main differences from equipment developed in other projects

Items improved from FY2021
No. *1Development issues
extracted from FY2021
results

Details of FY2022 countermeasures

Cable pinching during rod Encase the cable inside the telescopic rod. (Horizontal
retraction
development from other projects (Development ofTechnology for Detailed Investigation inside PCV))

2*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.

Category

Main differences from equipment developed in otherprojects

•
•
Wired
•
•
•
Wireless•

Addition of a cable feed mechanism at the tip of the rod
Addition of a cable guide ring
Addition of LED lighting to mark drone landing location
Pan tilt range of the camera at the tip of the rod
Addition of a radio at the tip of the rod
Addition of LED lighting to mark drone landing location

Cable feed mechanism
Simple composite
cable *2

Telescopic rod
Rod interior

Telescopic rod when extended
Cable guide ringInterior
tubingPTFEtape *4

Wired drone composite cable

Forward travel guideCounterweights(Total of bothsides: approx. 3kg)

LED tape
Backward travel guide*2 Alternative because long lead times for some products prevented cable unification

External view of FY2022 prototype(wired)Interior tubing for power and signal
cables(both wired and wireless drones)

Added cableguide rings
RollerRod
tip direction

Radio
Telescopic rod
Composite cable
Camera

Revision of the pan tilt range for thecamera on the tip of the wired drone
rod *3
Backward
travel guide

LED tape
Forward travel guide*3 To monitor the condition of the drone’s
composite cable at the rear of theequipment.

Wired drone
composite cableAppearance of the cable feed mechanism at
the tip of the rod on the wired drone

Addition of guiding rings for pre-operation verification*4 Cable guide rings and locations where the wired drone composite cable contacts theequipment were wrapped in PTFE tape to reduce chafing with the composite cable.

Overview of composite cable routing for wired drone

External view of FY2022 prototype(wireless)©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.55

4). FY2022 implementation details ③ FY2022 prototype (cable drum transfer cart for wired drone)
Main differences from equipment developed in other projects *2

Items improved from FY2021
No. *1Development issues extracted
from FY2021 results

5

Improved cable feed
- Event of cable feeding to theback of the drum
- Cable feed roller idling- Unable to verify feed rate

Details of FY2022 countermeasures- Review of cable drum structure and function- Review of the direction of the cable feed
- Improving roller clamping force- Adding camera to verify feed rate

Main differences from equipment developed in other projects•••

Addition of a cable guide ring
Revision of the forward travel guide structure
Addition of LED lighting to mark drone landing location*2 Installed the crawler currently in-development from among the investigationequipment used in the Development of Technology for Detailed Investigation
inside PCV PJ.

*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.

Cable guide ring
Direction ofcable feed

Composite cable *3
Forward travel
guide
Wired drone
composite cable

Event of cable feeding to the back of thedrum (FY2021)
Before travel guide improvement

Direction of cable feed

Cable drum
Backward travel guideExternal view of FY2022 prototype*3 Preliminary confirmation testing confirmed insufficient output power in the wired
drone due to voltage drop. The power supply cable inside the composite cableon the cable drum transfer cart was thin and caused a large voltage drop, so thecable was revised from AWG14 to AWG6. The diameter of the composite cableon the cable drum transfer cart is expected to be between Φ30 mm to Φ40 mm.

RollerAfter travel guide improvement

Revision of the forward travel
guide structure

Improved cable feed mechanism(FY2022)

Improved cable feed
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

No.56

Unit 1

4). FY2022 implementation details ③ FY2022 prototype (cable assistance device)
Main differences from equipment developed in other projects

Items improved from FY2021
No. *1

6

Development issues
extracted from FY2021
results
Treatment of cable drum
drive cable

Main differences from equipment developed in other projects
Details of FY2022 countermeasures
Prototype cable assistance device(Horizontal development from other projects(Development of Technology for Detailed Investigation
inside PCV))

Added a horizontal sliding mechanism to the cable assistance mechanism(to address the need to assist two composite cables for investigations witha wired drone)
Wired drone(investigation Telescopic rod
equipment)
transfer cart for
wired drone

Cable assistancedevice*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.
Cable drumtransfer cart

Wired drone investigation system
Telescopic rod
Mockup of transfer
cart composite
cablesCameraTelescopic rod
Mockup of transfer cart
composite cables

Horizontal slide
mechanism

Composite
cable

Cable drum
Mockup of transfer cart
composite cables

Cable drum
Mockup of transfer cart
composite cables

CrawlerCable assistancerollerExternal view of FY2022 prototype

When assisting two composite cables©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.57

4). FY2022 implementation details ③ FY2022 prototype (installation equipment for 350A (1/4))
Items improved from FY2021

No. *1Development issues
extracted from FY2021
results

20

Feasibility of X-2 Penepassage via installationequipment used in otherprojects

Main differences from equipment developed in other projects
Main differences from equipment developed in other projects

Details of FY2022 countermeasures
Prototype of installation equipment for 350A
(Horizontal development from other projects(Development of Technology for Detailed Investigation
inside PCV))

Added cable extrusion rollers(to address the need to handle two cables for investigations with a wired
drone)*1 Corresponding to development issues No.43 to 45 and the action policy (plan) development issue No.
Telescopic rod
Mockup oftransfer cart
composite cables
RollerRoller

Cable drum
Mockup oftransfer cart
composite cables

BucketBucketExternal view of FY2022 prototype
Handling of two composite cables©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.58

4). FY2022 implementation details ③ FY2022 prototype (installation equipment for 350A (2/4))

The image below shows installation of the equipment, using the 350 A Penetration during investigation with a wired drone.
Cable drum

PCV
exterior

Seal box

Cable drumtransfer cart

Wired drone

Installation equipment

Installed within the PCV

Telescopic rodtransfer cart

① Initial condition② Drone placement in the bucket③ Drone installation

Insidethe PCV④ Arrival of drone in PCV⑤ Drone rising⑥ Drone landing on platform©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.59

4). FY2022 implementation details ③ FY2022 prototype (installation equipment for 350A (3/4))

The image below shows installation of the equipment, using the 350 A Penetration during investigation with a wired drone.

Installed within the PCV⑦ Collection of installation equipment⑧ Installation of telescopic rodtransfer cart in the bucket⑨ Installation of telescopic rodtransfer cart

⑩ Arrival of telescopic rod transfer
cart in the PCV⑪ Bending of the bucket and lowering of
the telescopic rod transfer cart

⑫ Touchdown of the telescopic rodtransfer cart on the platform©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.60

4). FY2022 implementation details ③ FY2022 prototype (installation equipment for 350A (4/4))

The image below shows installation of the equipment, using the 350 A Penetration during investigation with a wired drone.

Installed within the PCV⑬ Collection of installation equipment⑭ Installation of the cable drumtransfer cart in the bucket⑮ Installation of the cable drumtransfer cart

⑯ Arrival of the cable drum transfer
cart in the PCV⑰ Bending of the bucket and lowering of
the cable drum transfer cart

⑱ Touchdown of the cable drum transfer
cart on the platform©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.61

4). FY2022 implementation details ④ Items for functional verification tests (1/3)

TargetCategory

Output/Assessment criteria

Relevant
sectionFlight height verification test

Ability to reach target height (wired: 7 m, wireless:
11 m)

No.73

②

Payload verification test

Maximum payload

No.74

FlightConducted Conducted performance(sway)③

Verification test for passing throughperformance in narrow part

- Minimum passable space- Amount of sway during flight (vertical orientation)

Flightperformance(flight time)

Flight time verification test

Maximum flight time④

Visibility/lighting
functions

⑤

Wired

Wireless

Items

Test
No.

Flightperformance (lift)①

Functional verification tests(a) Drone
Conducted Conducted
Conducted Conducted―

Conducted

Conducted Conducted

Conducted Conducted⑥

Conducted Conducted

⑦

―

―

Dose ratemeasurement
performance
Conducted (wireless only)
Conducted

⑧
⑨

No.75
and 76
No.77

Camera performance verification test
(Dark and vaporous environments)

Ability to see objects in dark and vaporous
environments

No.78
and 79Camera irradiation test

- Changes in images over time
- Radiation resistance (target: 1000 Gy)

No.80
and 81

In-flight visibility verification test

Image sway during flight

No.82

Dosimeter irradiation test

Measurable range (FY2022 development target: 0
to 100 Sv/h)No.83
and 84

Dosimeter noise influence verification
test

Effects of noise on dosimeter

Drone irradiation test

Radiation resistance of drones (target: 1000 Gy)

No.85
No.86 to88

Conducted Conducted

Radiation
resistance⑩

Conducted ConductedElectronic
component
performance⑪

Temperature / current value verification Change in temperature and current values oftestelectronic components (ESC) due to increases in
outputNo.89

Conducted Conducted

Waterproof
performance⑫

Waterproof performance verification
test

No.90

Waterproof performance (reference measurement)©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.62

4). FY2022 implementation details ④ Items for functional verification tests (2/3)

TargetCategory
Wired

Items

Wireless

Test
No.

Functional verification tests

Output/Assessment criteria

Relevant
section(b) Telescopic rod transfer cart
Traction performance
Conducted

Conducted

Conducted

Conducted

Tractive force verification test①

Driving performance

Conducted②

Rod
extension/retraction
Conducted Conducted
performance

Conducted

Conducted

Conducted

Conducted――

Driving performance verification test *Wired:
Tests (b)-② and (c)-② are conductedsimultaneously

Driving performance on grating(Dry or wet conditions)

Verification test of travelling ability

Ability to traverse remaining B1
investigation equipment(Dry or wet conditions)③

Conducted

Composite cable
feed/wind performance

Actual performance of cable
traction force(Dry or wet conditions)④

Rod extension/retraction test
(Wired: Tests (b)-④, ⑤, ⑥, ⑦ and (c)-④ areconducted simultaneously / Wireless: Tests(b)-④ and b-⑤ are conducted simultaneously)- Extension/retraction time
- Amount of deflection⑤

Passage performance verification test
(Wired: Tests (b)-④, ⑤, ⑥, ⑦ and (c)-④ areconducted simultaneously / Wireless: Tests(b)-④ and b-⑤ are conducted simultaneously)

Ability to pass structures in the
CRD opening⑥

Composite cable feeding/winding test (linkage
with rod extension/retraction)(Wired: Tests (b)-④, ⑤, ⑥, ⑦, and (c)-④ areconducted simultaneously)

Connection with rod
extension/retraction duringcomposite cable feeding/winding⑦

Composite cable feeding/winding test (linkage Connection with cable drum duringwith cable drum)
composite cable feeding/winding(*Wired: Tests (b)-④, ⑤, ⑥, ⑦, and (c)-④ areconducted simultaneously)

No.91 and 92

No.93

No.94

No.95 to 98©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.63

4). FY2022 implementation details ④ Items for functional verification tests (3/3)

Category
Wired Wireless(c) Cable drum transfer cart
Target

Items

Test
No.

Conducted―

Traction
performance①

Conducted―

Driving
performance②

Conducted―③
Composite cable
feed/windperformance④

Conducted ConductedTraction
performance①

Conducted Conducted

Driving
performance②

Cable assistance
performance

Conducted―

Output/Assessment criteria

Relevant
sectionTractive force verification test

Actual performance of cable traction force(Dry or wet conditions)

No.99

Driving performance verification test *Wired:
Tests (b)-② and (c)-② are conductedsimultaneously
Verification test of travelling ability

Driving performance on grating(Dry or wet conditions)No.100Functional verification tests

Composite cable feeding/winding test
(linkage with telescopic rod) *Wired: Tests(b)-④, ⑤, ⑥, ⑦ and (c)-④ are conductedsimultaneously

Ability to traverse remaining B1
investigation equipment(Dry or wet conditions)
Connection with cable drum duringcomposite cable feeding/winding

No.101

No.95 to 98(d) Cable assistance device
Tractive force verification test

Actual performance of cable traction force(Dry or wet conditions)

Driving performance verification test

Driving performance on grating(Dry or wet conditions)No.103 and104③

Cable grabbing performance verification test

Cable grabbing performance

No.105

Conducted Conducted④

Cable feed force verification test

Cable feed force / speed / clamping force

No.106 and107

Conducted Conducted⑤

Rollover verification test

Possibility of roling over when assisting
cablesNo.108①

Bending load verification test

Bending performance under load at thebucketConducted Conducted②

Cable feed force verification test

Cable feed force/clamping force

No.109 and110
No.111 and112

Conducted Conducted③

Cable feeding operations verification test

Two cables can be fed simultaneously ornot

Conducted Conducted

No.102(e) Installation equipment (for 350A)
Conducted ConductedInstall/uninstall
performance

No.113©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.64

4). FY2022 implementation details ⑤ Equipment for functional verification tests (1/2)
The following shows an overview of the test equipment for wired and wireless drones, the telescopic rodtransfer cart, and the cable drum transfer cart.
Mockup of remaining B1 investigation equipment

Approx. 10 m

Assumed RPV
opening position

Ladder edge

Mockup of remaining B1 investigation equipment

TIP guide
pipe
Inner
side ofopeningOuterside ofopening

Test frame

Simulated CRD opening

Simulated control room

Appearance of FY2022 test equipment©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.65

4). FY2022 implementation details ⑤ Equipment for functional verification tests (2/2)
The following shows an overview of the test equipment for the cable assistance device and350A installation equipment.
Simulated 350A Penetration

Simulated 350A Penetration

Mockup ofremaining B1
investigationequipment

Simulated platform inside the PCV

Mockup of remaining B1
investigation equipment

Appearance of FY2022 test equipment©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.664). FY2022 implementation details ⑥ Summary of results of functional verification tests (1/3)

Target

Items

Test
No.

Functionalverification tests

Output/Assessment
criteria

Test results
Wired specification

Applicability to actual equipment

Wireless specification

Wired specification

Wireless specification(a) Drone
Flightperformance(lift)

Flightperformance(sway)
Flightperformance(flight time)①

Flight height verification Ability to reach target heighttest(wired: 7 m, wireless: 11 m)

Can hover for 10 seconds attarget height (7 m)

Can hover for 10 seconds at target
height (11 m)

Prospect is to be able to reach thebottom of the RPV interior, whichis the survey location.

Prospect is to be able to reach the topof the core support plate.

Payload verification
test

Maximum payload

933 g

600 g

②

No payload margin when flying attarget flight height.

Additional components can beinstalled. However, the trade-off withflight time must be considered.

③

Verification test for
passing throughperformance in narrow
part① Minimum passable space② Amount of sway during
flight (vertical orientation)①: □700 mm / □500 mm(vertical/horizontal)②: 211 mm / 275 mm(length/width)①: □600 mm / □500 mm(vertical/horizontal)②: 253 mm / 258 mm (length/width)

Passable diameter for theassumed opening projected to beΦ1 m (however, dependent onpilot skill)

Passable diameter for the assumed
opening projected to be Φ1 m
(however, dependent on pilot skill)

Flight time verification
test

Maximum flight time―

Without dosimeter: 10 min. 4 sec.
With dosimeter: 8 min. 40 sec.
With dosimeter + weight (300 g): 6
min. 47 sec.

―

Camera performanceverification test (in dark
and vaporous
environments)

Ability to see objects in dark
and vaporous environments

Water vapor (none): 2.5 m
visibility confirmed
Water vapor (low): 2.5 m visibility
confirmed
Water vapor (high): 2.5 m visibility
not conﬁrmed

Water vapor (none): 2.5 m visibility
confirmed
Water vapor (low): 2.5 m visibility
confirmed
Water vapor (high): 2.5 m visibility
not conﬁrmed

Camera irradiation test

- Changes in images over time
- Radiation resistance (target:
1000 Gy)

Of cameras A through D, cameras B and C achieved the target
cumulative dose (1000 Gy)
Camera B weighs less and was selected as the camera for the drone

Radiation resistance is expected to be applicable for use with actual
equipment. However, radiation noise reduction methods for 1000 Gy/henvironments must be considered.

⑦

In-flight visibility
verification test

Image sway during flight

Flight caused no noticeable
deterioration in visibility

Projected to be able to see thesurvey target.

⑧

Dosimeter irradiation
test

Measurable range (FY2022
development target: 0 to 100
Sv/h)

Dosimeter noise
influence verification
test

Effects of noise on dosimeter⑨

Drone irradiation test

Radiation resistance of drones(target: 1000 Gy)④

Visibility/lighting
functions⑤⑥

Dose ratemeasurement
performance(wireless only)

Radiation
resistance⑩

Electronic
component
performance⑪

Waterproof
performance⑫

Temperature / current
value verification test

Change in temperature andcurrent values of electronic
components (ESC) due toincreases in output

Waterproof
performanceverification test

Waterproof performance(reference measurement)

Flight caused no noticeable
deterioration in visibility

Projected to be able to see RPVinterior walls with low water vapor
levels.

Limiting additional equipment can
extend flight time.

Projected to be able to see RPVinterior walls with low water vapor
levels.

Projected to be able to see the survey
target.

―Pulse measurement type: 0.09 to
1077 Sv/h
CMOS type: 0.08 to 90 Sv/h―

Pulse measurement type achieved
final target of 1000 Sh/h. Consider for
implementation in FY2023.

―

Pulse measurement type: Noiselevel during drone operation wasverified to have no effect on dose
rate measurement accuracy.

―

Electronic components failed at acumulative dose of 122 Gy

Electronic components failed at acumulative dose under 175 Gy

Operating methods and the
Operating methods and theconfiguration of electronic
configuration of electronic components
components on the drone must beon the drone must be reviewed.
reviewed.

The addition of an air cooling fan
had no effect

The addition of an air cooling fan
had no effect

The cooling function in the drone
must be reviewed.

The cooling function in the drone must
be reviewed.

Operable after sprayed with water

Operable after sprayed with waterMust be considered along withdust resistanceMust be considered along with dust
resistance

Reverify after manufacturing products
for actual equipment.

©International Research Institute for Nuclear Decommissioning6. Implementation details

No.67

Unit 1(2) Development of the bottom access investigation method (drone)4). FY2022 implementation details ⑥ Summary of results of functional verification tests (2/3)

Target

Items

Test
No.

Functional verification
tests

Output/Assessme
nt criteria

Tractive force verification test

Actual performance ofcable traction force(Dry or wet conditions)

Driving performanceverification test

Driving performanceon grating(Dry or wet conditions)

Verification test of travelling
ability

Test results
Wired specification

Applicability to actual equipment

Wireless specification

Wired specification

Wireless specification

A certain amount of tractive force
is confirmed. Planning to verify
applicability in future combined
tests.

A certain amount of tractive force isconfirmed. Planning to verify
applicability in future combined
tests.

A certain level of drivability wasconfirmed. Planning to evaluate
cable handling, etc. in futurecombined tests.

A certain level of drivability wasconfirmed. Planning to verify
applicability in future combined
tests.

(b) Telescopic rod transfer cart
Traction
performance

Driving
performance

Dry: approx. 274 to 392 N
Wet: approx. 98 to 196 N

Dry: approx. 245 to 343 N
Wet: approx. 98 to 215 N

Can drive back and forth overgrating in dry or wet conditions
without issue

Can drive back and forth overgrating in dry or wet conditions
without issue

Ability to traverse
remaining B1
investigationequipment(Dry or wet conditions)

Dry: Can travel forward andbackward
Wet: Can travel forward andbackward

Dry: Can travel forward andbackward
Wet: Can travel forward andbackward

Projected to be able to travel over
the remaining B1 investigationequipment. Planning to verify
applicability in future combined
tests.

Projected to be able to travel over
the remaining B1 investigationequipment. Planning to verify
applicability in future combined
tests.

④

Rod extension/retraction test
(Wired: Tests (b)-④, ⑤, ⑥,⑦ and (c)-④ are conductedsimultaneously / Wireless:Tests (b)-④ and b-⑤ are
conducted simultaneously)① Extension/retractiontime② Deflection

Initial rod angle: 14.3°①: 5 min. 15 sec. / 7 min. 36 sec.
(Extension/retraction)②: Approx. 150 mm

Initial rod angle: 12.1°①: 6 min. 6 sec. / 7 min. 37 sec.
(Extension/retraction)②: Approx. 185 mm

Check rod passability and linkage
between rod and cable drum.
However, the assumed procedure
for actual equipment will be
optimized in future combined tests
in order to evaluate applicability.

Rod passability was confirmed. The
assumed procedure for actual
equipment will be optimized in futurecombined tests in order to evaluate
applicability.

Ability to passstructures in the CRD
opening

Passable at initial rod angle (14.3°) Passable at initial rod angle (12.1°)⑤

Passage performanceverification test
(Wired: Tests (b)-④, ⑤, ⑥,⑦ and (c)-④ are conductedsimultaneously / Wireless:Tests (b)-④ and b-⑤ are
conducted simultaneously)⑥

Composite cable
feeding/winding test (linkage
with rod extension/retraction)(Wired: Tests (b)-④, ⑤, ⑥,⑦, and (c)-④ are conductedsimultaneously)

Connection with rod
extension/retraction
during composite
cable feeding/winding

Interlocking is projected to bepossible by using the cable ringguides to align the composite
cable. However, there is room for
optimization in the assumed
procedure for actual equipment.

Composite cable
feeding/winding test (linkage
with cable drum)(Wired: Tests (b)-④, ⑤, ⑥,⑦, and (c)-④ are conductedsimultaneously)

Connection with cable Interlocking is projected to be
drum during composite possible by using the cable ringcable feeding/winding
guides to align the composite
cable. However, there is room for
optimization in the assumed
procedure for actual equipment.

①

②

③

Rod
extension/retr
actionperformance

Composite
cable
feed/windperformance

⑦

－

－

－

－

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.68

4). FY2022 implementation details ⑥ Summary of results of functional verification tests (3/3)

Target

Items

Test
No.

Test results
Functional verification tests

Output/Assessment criteria

Applicability to actual equipment
Wireless
specification

Wired specification

Wireless
specification

Dry: approx. 245 to 392 N
Wet: approx. 215 to 294 N―

A certain amount of tractive force is confirmed.
Planning to verify applicability in future combined
tests.

―Can drive back and forth over grating in dry
or wet conditions without issue―

A certain level of drivability was confirmed.
Planning to evaluate cable handling, etc. infuture combined tests.

――

Projected to be able to travel over the remaining
B1 investigation equipment. Planning to verify
applicability in future combined tests.

――

Verify the linkage between the rod and cable
drum. However, the assumed procedure for
actual equipment will be optimized in futurecombined tests in order to evaluate applicability.

―

Wired specification(c) Cable drum transfer cart
Traction
performance①

Driving
performance②

Tractive force verification test

Actual performance of cable traction
force (dry or wet conditions)

Driving performance verification test

Driving performance on grating (dry or
wet conditions)

Verification test of travelling ability

Ability to traverse remaining B1
investigation equipment (dry or wet
conditions)

Dry: Can travel forward and backward
Wet: Can travel forward and backward

Composite cable feeding/winding test
(linkage with telescopic rod) *Wired:
Tests (b)-④, ⑤, ⑥, ⑦ and (c)-④ areconducted simultaneously

Connection with cable drum duringcomposite cable feeding/winding

Interlocking is projected to be possible byusing the cable ring guides to align thecomposite cable. However, there is roomfor optimization in the assumed procedure
for actual equipment.

Tractive force verification test

Actual performance of cable traction
force (dry or wet conditions)Target tractive force (100 N) achieved under all conditions.
Traction in wet conditions was about 10% less than in dry
conditions

A certain amount of tractive force is confirmed. Planning to verify
applicability in future combined tests.

③
Composite
cable
feed/windperformance④(d) Cable assistance device
Traction
performance①

Driving
performance②

Driving performance verification test

Driving performance on grating (dry or
wet conditions)

Can drive back and forth over grating in dry or wet conditions
without issue

A certain level of drivability was confirmed. Planning to verify
applicability in future combined tests.

Cable
assistance
performance③

Cable grabbing performanceverification test

Cable grabbing performance

Capable of grabbing composite cables on both sides ofequipment

Projected to be able to grab cables.

Cable feed force verification test

Cable feed force / speed / clamping
force

Target feed force (100 N) achieved under all conditions.

A certain amount of feed force was confirmed. Planning to verify
applicability in future combined tests.

Rollover verification test

Possibility of roling over cables

Each operation poses a low risk of roling over *Recovery is
possible if the angle of fall is less than 90°.

Projected low likelihood of roling over from each operation.

Bending load verification test

Bending performance under load at thebucketCapable of conducting bending operations with 65 kg load

A certain level of installation feasibility was confirmed. Planningto verify applicability in future combined tests.

②

Cable feed force verification test

Cable feed force/clamping force

Target feed force (100 N) achieved with both Φ40 mm andΦ10 mm cables③

Cable feeding operations verification
test

Two cables can be fed simultaneously or Can feed two cables simultaneously without difficulty
not

④
⑤

(e) Installation equipment (for 350A)
Install/uninstall
performance①©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.69[Wireless]: Wireless drone4). FY2022 implementation details ⑦ Other items for consideration (impact of drone crashes) [Wired]: Wired drone

Assumedrisk

Cause of event

Countermeasures and responses
Risk reduction measures

Response during occurrence

Drone crash
Collision with an obstacle

FailureInsufficient flight stability- Mount two cameras with a pan tilt mechanism or wide-angle lens. [Wired / wireless]- Consider the installation of sensors to detect obstacles.
- Reattempt the flight.
- In worst case scenarios,
leave the drone where it- Improve flight stability by enhancing control performance.
is.

Insufficient durability andradiation resistance- Conduct resistance tests on circuits and machinery.
- Only install components with sufficient radiation resistance.

Ingress of water and/or dust

Apply dustproof and waterproof measures and conduct testing toverify.

Camera blind spots and poor
visibility[Wired]- If flight is not possible,
wind the cable to reel inand collect the drone.

[Wireless] Communication failure due to insufficient signal - Use the extension rod to place a radio transceiver inside thepedestal.
strength- Conduct mockup testing to verify transmission stability.
[Wireless] Dead battery- Install a high-capacity battery.
- Check remaining battery power during flight.

- When the remaining battery charge approaches theamount required for the return trip, suspend theinvestigation and have the drone return.
- In worst case scenarios, leave the drone where it is.

Impact on plant during drone flight or crash(Flight) Damage to X100B thermometer/waterlevel gauge

Drone crashes into the section - Conduct the investigation using a route that is not extremely
not protected by steel pipe
close to the X-100B thermometer/water level gauge.

- Continue measuring data using the undamaged
portion of the X-100B thermometer/water level
gauge.

(Flight) Increased dustlevels in the PCV interior

Winding from drone flightscatters dust

- If the effect of dust is a concern, consider countermeasures byreviewing operations and components.

- If dust levels exceed permissible values, temporarily
land the drone and enter standby or retrieve thedrone.

(Flight) Fluctuation in
PCV thermometerreadings

Winding from drone flight
impacts the thermometer- If there is concern about fluctuations in thermometer readings,
consider countermeasures by reviewing operations andcomponents.

- If measurements must be made using a thermometerwithin the PCV interior, either land the drone or fly it
at a distance from the thermometer.

(Failure) Fire

[Wireless] Battery fire

- Properly protect the drone so that it is not damaged by external
forces.
- Select batteries with excellent durability and verify that they do
not catch fire even under severe conditions.

- Monitor the situation with other devices.

(Crash) Hydrogengeneration[Wireless] Battery reacts withaccumulated water- Apply waterproof treatments to prevent a reaction between water - Monitor the hydrogen concentration value in the PCV
and the cells inside the drone.
interior.
- Examine the amount of hydrogen generated from the battery.

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.70

4). FY2022 implementation details ⑦ Other items for consideration (sensing technologies and flight control)

Risks associated with drone flight
Potential risk

Impact of risk

Unstable drone attitude during flight① Collisions with obstacles and crashes② Inability to fly in narrow areas③ Blurry investigation images

Obstacles may be difficult to verify with existing cameras① Collisions with obstacles and crashes

Operator is constantly overburdened and cannot rest during flight④ Possibility of operational errors occurring

Only highly skilled and experienced operators can pilot the drones⑤ Difficulty in securing human resources during investigations at
the siteDrones are unable to determine their position and attitude⑥ Unable to identify the location for investigation

Development items for risk elimination (proposal)
Development item

Development of drone
sensing technology

Development of drone flightcontrol technologies

Target result
Estimation of position
and attitude
Assessing the state ofobstacles in thesurrounding area

Improved stability during
flight

Method utilized (proposed)- Input to flight control- Identification of the target
investigation location (⑥)- Collision and crash avoidance(①)
RGB image- Collision and crash avoidance(①)- Investigation in narrow areas (②)- Reduction of blur in investigation
images (③)- Reduction of burden on operator(④)- Improved operability for nonskilled workers (⑤)

Point cloud depth image(Reference) Image from a point cloud data sensor
mounted on investigation equipment in anotherproject (Detailed Investigation inside PCV)(① to ⑥ correspond to the number in the risk table)©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.71

5). Summary① FY2022 results- Based on results up to FY2021, issues were identified and countermeasures were examined.
- Access equipment under development in other projects were customized and the investigation plan and development plan were studied in consideration of integratingthat equipment into the plans.
- The specifications of each device were studied, and devices were designed and manufactured. Functional verification tests were also conducted on these devices toevaluate their performance of the functions.

② Issues for FY2023 onward- Review the development plan and reflect the results of functional verification tests. Also improve equipment.
- Use combined tests to confirm the feasibility of the investigation method and proceed with the development of equipment for actual equipment.
- Identify risks for actual equipment and incorporate them into the design as necessary. Complete operational scenarios.
Cable feed mechanism
Upper camera
Tilt: 0 to 90°

Telescopic rod

Roller
Cable drum

Forwardtravel guide
Lower camera
Pan: ±180°
Tilt: 0 to 90°

Forward travel
guide
LED tape
Backward travel guide

Wired drone

BucketBackward
travel guide

Cable drum transfer cart
Telescopic rod transfer cart for wired drone

Upper camera
Tilt: 0 to 90°

Composite
cable

TelescopicrodInstallation equipment for 350A

CameraRadio

Horizontal slide
mechanism

Batterycase
Lower camera
No pan or tilt

Mock
dosimeter

Wireless drone

Backward
travel guide

LED tape
Forward travel guide

Telescopic rod transfer cart for wireless drone

CrawlerCableassistance roller

Cable assistance device

External view of FY2022 prototype©International Research Institute for Nuclear Decommissioning

No.72

Supplementary materials for results ofdrone functional verification tests aredescribed in No.73 – 113.

©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.73(Supplementary material) Results of functional verification tests for FY2022 (drone)

Test (a)-①: [Flight height verification test]
TargetDrone (wired / wireless)

Test method① Device placed at the position expected for the actual equipment.
② Flew drone to the mark on the test frame (wired: 7 m, wireless: 11 m) and hovered it there for 10 seconds.
③ For wired only, measured maximum flight height. (Reference measurement)

Output/Assessment
criteria

Ability to hover for 10 seconds at target height (wired: 7 m, wireless: 11 m)

Test results

Flight height verification test

No.

Drone

Capabilityof reachingtargetheightCapability of hovering for 10
seconds at target height[Reference
measurement]
Maximum flightheight

1

Wired

7m
reachable

Able to hover for 10
seconds

8m
reachable

2

Wireless

11 mreachable

Able to hover for 10
seconds-⚫ Both wired and wireless drones were capable of hovering for
10 seconds at the target height (wired: 7 m, wireless: 11 m).

Drone in flight (wired)

Flight height test
performance (wireless)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.74

Unit 1(2) Development of the bottom access investigation method (drone)(Supplementary material) Results of functional verification tests for FY2022 (drone)

Test (a)-②: [Payload verification test]
TargetDrone (wired / wireless)① Loaded weight, then hovered drone at a height of 1 m above the floor.
② If able to hover for 10 seconds, added more weight and hovered drone
Test method
again at a height of 1 m above the floor.
③ Repeated ② until the drone could no longer hover for 10 seconds, andverified maximum payload.
Output/Maximum payload that can be hovered for 10 seconds at a flight height ofAssessment
1m
criteria

Test results

Weight/s
Weight/s

Drones loaded with weights (left: wired, right: wireless)

Payload verification test results

No.

Drone

Maximum
payload [g]

1

Wired

933 (*1)

Airframe mass: 1650 g
Cable mass: 133 g/m

2

Wireless

600 (*2)

Airframe mass: 1989 g
Dosimeter: 200 g

Remarks(*1) Weight (800 g) + 1 m of cable (133 g)(*2) Dosimeter (200 g) + 1 m of cable (133 g)

Flight performance at height of 1 m (left: wired, right: wireless)⚫ The maximum payload that could be hovered for 10 seconds at a flight height of 1 m was 933 g for wired drones and 600 g
for wireless drones.

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1No.75(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-③: [Verification test for passing through performance in narrow part (1/2)]
TargetDrone (wired / wireless)① Flew drone back and forth within a □1000 mm x 5000 mm rectangular prism flight path. Checked horizontal and vertical flight path patterns.
Test method ② If the drone passed, reduced the flight path dimensions and flew drone through again.
[Note] For the vertical orientation, motion capture was used to measure the amount of fluctuation during flight.

Output/- Dimensions of smallest possible flight path
Assessment- Amount of fluctuation during flight (vertical orientation)
criteria
Motion capture
cameraMotioncapturemarkerFrame set-up during flight invertical orientation

Placement of motion capture markers

Drone position
Camera position

Arrangement of motion capture cameras

Frame set-up during flight inhorizontal orientation

View of PC screen during motion capture

Overview of motion capture system©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.76(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-③: [Verification test for passing through performance in narrow part (2/2)]
Results of verification test for passing through performance in narrow part(vertical orientation)
Amount of fluctuation during flight [mm]Test results(Vertical
orientation)

Category

Passagedimensions[mm]

Passage capability

FY2022 wired drone□700

FY2022 wireless drone
FY2021 wireless drone

Long direction(including thedimensions of thedrone)

Short direction(including thedimensions of thedrone)

Round trip passage
possible211 (581)

275 (545)

Measurement error is ±0.64
mm

□600

Round trip passage
possible (*1)

253 (573)

258 (528)

Measurement error ±0.587
mm

□700

Round trip passage
possible

200 (650)

347 (617)

Measurement error is ±0.64mm

Remarks*1 During descent there were cases in which a camera noise caused the aircraft to lose its position for a moment and fly out of the frame.

Wireless drone camera
footage (□700 mm
condition)

Wired drone camera
footage (□600 mm
condition)⚫ Based on measurements of fluctuation, FY2022 wired / wireless drones are expected to be able to pass through the □600 mm frame.
⚫ For the FY2021 wireless drone, □800 mm was the smallest flyable passage in the FY2021 element test, but in FY2022 a □700 mm passage was used for the firsttime as a reference, and the drone was able to pass through. Based on the measurements of fluctuation, □700 mm is considered the minimum passabledimension.
⚫ Results for FY2021 and FY2022 wireless drone prototypes were compared and no significant difference in the amount of fluctuation was observed.

Results of verification test for passing through performance in narrowpart(horizontal orientation)
Category

Passage dimensions [mm]Passage capability□500

Round trip passage
possible□400

Round trip passage notpossible□500

Round trip passage
possible□400

Round trip passage notpossible

FY2022 wired drone

Test results(Horizontal
orientation)

FY2022 wireless drone

Wired drone camera
footage (□400 mm
condition)

Wireless drone camera
footage (□400 mm
condition)⚫ FY2022 wired / wireless drones were able to pass through the □500 mm frame. (□600 mm was the smallest flyable passage for FY2021 element test results)©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.77(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-④: [Flight time verification test]

Test
methodDrone (wireless)① Equipped drone with two commercial
batteries (4600 mAh).
② Flew drone until it became unable to fly,and measured the time until landing.
③ ​The flight method was repeated ascentand decent between 1 and 7 m.
④ Kept flight speed low, avoided sudden
rises and falls.
⑤ The mass of the drone had one of thefollowing three patterns.
(1) Without mock dosimeter (200 g)(2) With mock dosimeter (200 g)(3) Mock dosimeter (200 g) + weight (300g)[Note] For reference, the test was also
conducted with a mock dosimeter (200 g) +the wireless drone’s maximum payload (600g).

Amount of time drone can remain in flight
Output/[Note] In the FY2021 element test (two 3500
Assessment
mAh batteries) the drone could remain in flight
criteria
for about 6 minutes.

Test results

Results of flight time verification test
Battery 1 charge [%]No.

Combination of mock dosimeter
and weight(additional mass)

Maximum flighttime

Before flight1

Without mock dosimeter (200 g)

10 min. 4 sec.

2

With mock dosimeter (200 g)

8 min. 40 sec.

3

Mock dosimeter (200 g) + weight(300 g)(Reference)

Mock dosimeter (200 g) + weight(600 g)Battery 2 charge [%][After flight]

Beforeflight[After flight]

100

0

100

0

100

0

99

0

6 min. 47 sec.

99

0

100

1

2 min. 44 sec.

99

38

100

41

700
Wireless drone

Weight/s

Flight duration (secs)

Target

600

500
400
300
200
100
0
-400 -200

Adjustment of additional weight(Mock dosimeter (200 g) + weight(600 g))Wireless drone in flight

0

200

400

600

800

Additional mass (g)Additional mass - characteristics offlight time

⚫ The flight time with the mock dosimeter (200 g) wasapproximately 8 min. 40 sec.
⚫ It was also confirmed that flight time decreases in proportion to
the increase in additional mass.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.78(Supplementary material). Results of functional verification tests for FY2022 (drone)
Test (a)-⑤: [Camera performance verification test (in dark and vaporous environments) (1/2)]
Target

Test method

Drone (wired / wireless)
1. Darkness condition①Horizontally installed a □1000 mm × 7000 mm square pillar (aluminum frame).
②Installed discernment sheets at a distance of 1 m, 2.5 m, and 5 m from the edge of the aluminum frame.
③Covered the aluminum frame with a blackout curtain to create the dark condition, and placed drone at the edge of the aluminum frame.
④Turned on drone-mounted LED lights, took footage of the discernment sheets, and reviewed footage.
2. Darkness + water vapor condition①Checked the footage from investigation inside the PCV, and filled the dark room with water vapor to approximate actual equipment
conditions. (*1)
②Turned on drone-mounted LED lights, took footage of the discernment sheets, and reviewed footage. (*2)(*1) An illuminometer was set up at 5 m from the edge of the aluminum frame to measure illuminance when the LED lighting was turned on
without water vapor. The room was filled with water vapor until the illuminance was about 1/3 to 1/2 or 1/10 of said illuminance.
(*2) Recording was conducted without drone propeller rotation for the darkness condition, and with drone propeller rotation for the darkness+ water vapor condition.

Output/Assessment
Ability to see objects 2.5 m away in a dark, water vapor-filled environment.
criteria

Discernment
sheetsInstallation of discernment sheets

Installation of blackout curtain(dark condition)

Darkness + water vapor©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.79(Supplementary material). Results of functional verification tests for FY2022 (drone)
Test (a)-⑤: [Camera performance verification test (in dark and vaporous environments) (2/2)]
Test results
No.

Water
vapor

1

Camera performance verification test results(in dark and vaporous environments)

IlluminanceDrone
at 5 m away
specification
[lux]

Wired

3.7

Distancefromcamera[m]

Assessment

Resolution

1

Discernable□30 mm

Dots (□30 mm) can be discerned.

2.5

Discernable□30 mm

Dots (□30 mm) can be discerned.

5

Partially
discernable

300 ×
420 mmThe A3 sheet (300 × 420 mm) is discernable but
the dots (□30 mm) are not.

No

2

Wireless

3

Wired

1.8

1.9

Yes
(low)
4

Wireless

5

Wired

0.5

0.2

Yes
(high)
6

Wireless

0.1

Visibility
Details

1

Discernable□30 mm

Dots (□30 mm) can be discerned.

2.5

Discernable□30 mm

Dots (□30 mm) can be discerned.

5

Partially
discernable

300 ×
420 mmThe A3 sheet (300 × 420 mm) is discernable but
the dots (□30 mm) are not.

1

Discernable□30 mm

Dots (□30 mm) can be discerned.

2.5

Discernable□30 mm

Dots (□30 mm) can be discerned.

5

Not
discernable

N/A

1

Discernable□30 mm

Dots (□30 mm) can be discerned.

2.5

Partially
discernable□30 mm orlargerDepending on how much water vapor is on the A3
sheet, the dots (□30 mm) may or may not be
discernable.

5

Not
discernable

N/A

The A3 sheet (300 × 600 mm) is not discernable.

1

Discernable□30 mm

2.5

Notdiscernable

N/A

The A3 sheet (300 × 420 mm) is not discernable.

5

Not
discernable

N/A

The A3 sheet (300 × 420 mm) is not discernable.

1

Discernable□30 mm

2.5

Notdiscernable

N/A

The A3 sheet (300 × 420 mm) is not discernable.

5

Not
discernable

N/A

The A3 sheet (300 × 420 mm) is not discernable.

The A3 sheet (300 × 420 mm) is not discernable.

Dots (□30 mm) can be discerned.

Drone camera footage
Environmental
conditions

Wired drone

Wireless drone

Darkness(Water vapor:none)

Darkness +water vapor(Water vapor:small amount)

Darkness +water vapor(Water vapor:large amount)

Dots (□30 mm) can be discerned.

⚫ In darkness, the camera could discern an object 2.5 m away.
⚫ For the darkness + water vapor condition, discernment was possible
only up to 1 m away when water vapor was relatively high, but 2.5 m
away when water vapor was low.

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

No.80

Unit 1(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑥: [Camera irradiation test (1/2)]
TargetDrone (wired / wireless)
SourceCobalt-60① In order to determine camera installation position, measured and confirmed inadvance the location where radiation was 1000 Gy/h.
② Installed cameras A to D one by one from top to bottom at the location where
Test method
radiation was 1000 Gy/h. Also installed other equipment in designated locations.
③ Initiated irradiation. During irradiation, constantly filmed the discernment sheetson camera, and stored the footage.
Output/- Changes in images over time
Assessment - Radiation resistance (target: 1000 Gy)
criteria

Four irradiated cameras*1
No.

A

B

C

D

Appearance

Camera placement*2
Model no.

RVC801

BIC263

CMOS-320

MS-183HTTR23

Camera sensors

CMOS (1/4 inch)

CMOS (1/4 inch)

CMOS (1/3.6 inch)

CMOS (1/3 inch)

Resolution

Approx. 320000 pixels

Approx. 400000 pixels

Approx. 330000 pixels

Approx. 470000 pixels

Dimensions

23 mm × 21 mm × 34 mm

Exposure: Φ28 × 12 mm
Embedding: Φ23 × 15 mm

23.4 mm × 23.4 mm × 26.1 mm

26 mm × 23 mm × 25 mm

Mass

25 g (camera body)

17 g (camera body)

23 g (camera body)

80 g (camera body)Angle of view

140° horizontal / 105°
vertical

180° horizontal

195° horizontal

110° horizontal

Operatingtemperature-20 to +65°C-20 to +65°C―-20 to +50°C

Dustproof /waterproof

IP67

IP67

IP67

IP67

Video
transmission
method

NTSC

NTSC

NTSC

NTSC

*1 Taking into consideration the required specifications, inventory, delivery dates, etc., from among 20 small cameras, 4 were selected.

*2 Based on repeated pre-measurements, it was decided to conduct theirradiation test by placing the camera at the point where radiation is 1009 Gy/h(because it is difficult to find the exact point where 1000 Gy/h is reached).

View of the camera monitor *3*3 CAMERA 01/02/03/04 footage is from cameras A/B/C/D respectively.
©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.81(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑥: [Camera irradiation test (2/2)]
Test results

Camera A

Camera B

Camera irradiation test results
Category

Radiation
resistance

Camera A

420 GyVideo status
Radiation noise was observed from thestart of irradiation, and the video wasinterrupted at 420 Gy.

Radiation noise was observed from thestart of irradiation, but there was no
Camera B Over 1000 Gy
interruption to video recording during theirradiation test.

Camera C Over 1000 Gy

Radiation noise was observed from thestart of irradiation, but there was nointerruption to video recording during theirradiation test.

Camera D

Radiation noise was observed from thestart of irradiation, and video recording
failed at 957 Gy.

957 GyCamera C

Camera D① Before irradiation test (without
radiation source)② Radiation source installed(Start of irradiation: 0 min.)③ After about 25 minutes ofirradiation: 420 Gy accumulated dose

④ After about 57 minutes of irradiation:
957 Gy accumulated dose

⑤ After 60 minutes of irradiation:
1009 Gy accumulated dose

⑥ After irradiation test (without
radiation source)

Changes in camera footage over time
⚫ About 25 minutes after the start of irradiation, video recording from Camera D failed, (420 Gy accumulated dose), followed by recording from
Camera A about 57 minutes later (957 Gy accumulated dose).
⚫ Video recording from both cameras B and C was uninterrupted, even when the accumulated radiation dose exceeded the 1000 Gy target value
for radiation resistance.
⚫ Camera B is lighter than Camera C (Camera B: 17 g, Camera C: 23 g), so Camera B was chosen for the drone camera on account ofcompatibility with drone mounting.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.82(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑦: [In-flight visibility verification test]
Target

Test results

Drone (wired / wireless)① Placed a discernment sheet at a height of 7 m from the floor andfilmed it with the camera for 10 seconds.
② Installed discernment sheets 1 m and 2.5 m from the center of
Test method
the aluminum frame. (See figure below.)③ Filmed the discernment sheets 1 m and 2.5 m away while
grounded, and compared to video recorded during flight.
Output/Assessment Severity of disturbance to camera footage during flight
criteria

Wired drone (left: in flight, right: grounded)
Discernment
sheets (A, D)

D

DDiscernment
sheet (D)1m
A

Wireless drone (left: in flight, right: grounded)
Aluminum frame

Image of view in ( ) direction
Test frame⚫ For both wired and wireless systems there was no significant difference invideo footage (visibility) recorded during fight versus while grounded. (*)(*) The dot pattern of the discernment sheet was discernable in the footage
during flight.
⚫ Flight control technology, including quantitative evaluation of the amount offluctuation, is scheduled for study from FY2023 onward.

Test frame (ground plan)©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.83(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑧: [Dosimeter irradiation test (1/2)]
TargetCompact dosimeter (pulse measurement type) (for wireless drones)

Test
methodIrradiated the prototype with γ-rays in the 60Co irradiation chamberand evaluated the dose rate linearity•

The actual value of radiation resistance is scheduled to beevaluated from FY2023 onward

Verification
items /
Verification of measurable range of dose rateassessment (Target development value for FY2022 (1 to 100 Sv/h))
criteria

Inside theirradiationchamber

1.0E+6
Sensor: PD

Outside theirradiationchamber•

γ-ray

60Co radiation source•

Measurement PC

Because wireless communication is notpossible between the inside andoutside of the irradiation chamber, acompact dosimeter (inside theirradiation chamber) and ameasurement PC (outside theirradiation chamber) are connected by
LAN cable
Measured count rates at each dose
rate and assessed linearity

1.0E+4

Count rate [cps]LAN cable
LAN
cable

Sensor: APD

1.0E+5

Test
results

Compact dosimeter

Photodiodes (PD) and avalanche photodiodes (APD) wereconfirmed to have dose rate linearity from 0.09 to 1077 Sv/h,meeting the FY2022 development target value (1 to 100 Sv/h)

1.0E+3

1.0E+2

1.0E+1

FY2022 target range

Linearity confirmed from 0.09 to 1077 Sv/h

1.0E+01.0E-2

1.0E-1

1.0E+01.0E+1

1.0E+2

1.0E+3

Dose rate [Sv/h]Results of dose rate linearity assessment

Test system©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.84(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑧: [Dosimeter irradiation test (2/2)]
TargetCompact dosimeter (CMOS type) (for wireless drone)

TestmethodIrradiated the prototype with γ-rays in the 60Co irradiationchamber, assessed dose rate linearity• Count of number of luminous pixels in the image at each dose rate

Verification Verification of measurable range of dose rate
items
(Target development value for FY2022 (1 to 100 Sv/h))

Number of luminous pixels

IO-DATAGV-USB2
video capture

9.6 Sv/h

42 Sv/h

1.E+06

Test
results

CMOS

1.E+05

1.E+04

1.E+03

1.E+02
0.01

PC

0.1

1

10

100

Dose rate (Sv/h)Results of dose rate linearity assessment
•

Co-60

Test system

Confirmed that there is a correlation between the number ofluminous pixels and the dose rate at 0.08 to 90 Sv/h, and it
was possible to measure the dose rate

The actual value of radiation resistance is scheduled to beevaluated from FY2023 onward©International Research Institute for Nuclear Decommissioning6. Implementation details

No.85

Unit 1(2) Development of the bottom access investigation method (drone)(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑨: [Dosimeter noise influence verification test]
TargetCompact dosimeter (pulse measurement type) (for wireless)

•

•

•

•

Mounted a compact dosimeter on the drone, measured count rate fromthe time the drone started until the time it stopped
Compared two methods of supplying power to dosimeters: dry cellbatteries / drone batteries

Test method

Configuration①②

Verification
items /
assessment
criteria

•
•

Power
sourceDry cellbattery
Drone

In configurations ① and ②, the count rate of the photodiode(PD) and avalanche photodiode (APD) was 0 cps.
Based on the peak value spectrum measurement results, it
was confirmed that the noise level during drone operation was
below the threshold at the time of dose rate measurement andhad no effect on the accuracy of dose rate measurement

Properties

Results of count rate measurement

Electrical separation of drone anddosimeter
Supply of 6 V/2 A from drone battery (15V) to dosimeter

Threshold set below the value at the time of dose rate measurement andcount rate of 0 cps
Threshold at the time of dose rate measurement: 100 channels (PD), 0.2
V (APD)

Wireless drone

Test
results

Radio

PD

APD

①
(Dry cell battery)0(Threshold: 50 ch.)0(Threshold: 0.2 V)②(Drone battery)0(Threshold: 50 ch.)0(Threshold: 0.2 V)

Results of peak value spectrum
measurement (Configuration ②, PD)

Measurement PC

Compact dosimeter

Number of counts

1.0E+6Flight state

Threshold at thetime of dose ratemeasurement(100 channels)

1.0E+5
1.0E+4124 Sv/h
Sv/h (想定)124(hypothesized)
Drone
noise
ドローンノイズ

1.0E+3
1.0E+2
1.0E+1
1.0E+00

Test system

Unit: cps

Configuration

100

200

300

400

500

600

Channel©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.86(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑩: [Drone irradiation test (1/3)]
Target

Test method

Drone (wired / wireless)① Used wired and wireless drones, excluding the airframe, for irradiation with 1000 Gy/h.
② During irradiation, activated the drone, monitored camera footage and voltage values, and terminated irradiation if any
abnormalities were found in the camera footage or voltage values.
③ After irradiation, checked the operation of each on-board device to identify which on-board device malfunctioned.
[Note] A digital voltmeter was added so that voltage values could be verified via the camera footage.

Output/Assessment
Components resistant to radiation of 1000 Gy/h (target)
criteria

Below is a water tank, and the γ-ray
source is inside. The radiation
source rises through this slit andreaches the set dose rate.
A digital voltmeter wasadded so that voltage
values could be verified
via the camera footage.

Dose rate ismeasured at
the center ofthe panel.

Digital voltmeter

Dose rate measurement©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.87(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑩: [Drone irradiation test (2/3)]
Test results (wired drone)
Beforeirradiation

During increaseof radiation dose

Changes in drone over timeTime
irradiatedCumulative dose

1071 Gy/hChanges in camera footage over time

Drone status

0 to 6 min.

107 GyThe camera footage became
noisy and only the digital
voltmeter display was
discernable. Pan-tilt (panningand tilting) of the camera waspossible.

6 min. 53
sec.

122 GyPan-tilt became uncontrollable.

7 min. 1
sec.

125 GyThe pan-tilt angle was pulled
downward under the camera’s
own weight.

7 min. 31
sec.

134 GyTest completed.

⚫ The camera’s pan-tilt camera became uncontrollable at a cumulative dose of 122 Gy.
⚫ No significant change was observed in the voltage values before and after irradiation.
⚫ After irradiation, since the propeller motor could not be operated by the controller, a PC wasconnected to the flight controller to check operation. Since the response could be confirmed on
the PC, it was concluded that the motor would not operate because the flight controller orelectronic components (ESC) were not outputting a signal.
⚫ The FY2021 irradiation test was conducted without a supply of electric current, so the FY2022
irradiation test was conducted with a supply of electric current, but as in FY2021, malfunctions
were observed at a cumulative dose of about 100 Gy, so the procedures for drone operations
and the configuration of electric parts in the airframe need to be reviewed.

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.88(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑩: [Drone irradiation test (3/3)]
Test results (wireless drone)
During increaseof radiation dose

Beforeirradiation

1071 Gy/h
The voltmeter
display can beverified.

Changes in camera footage over time
Changes in drone over timeTime
irradiated0 to 10min.

Cumulative dose175 GyDrone status
The camera footage became
noisy and only the digital
voltmeter display was
discernable.

⚫ The noise in the camera footage made it impossible to check the operation of the motors andservo motors, and since it was impossible to verify abnormalities, the test was completed in 10
minutes based on the wired drone results.
⚫ No significant change was observed in the voltage values before and after irradiation.
⚫ After irradiation, the propeller motor could not be operated using the controller.
⚫ The LED display on the receiver antenna for the control system was off, indicating that thereceiver was damaged and inoperable. Additionally, since camera footage could be checked
even after irradiation, it was concluded that there was no abnormality in the video transmitter.
⚫ The FY2021 irradiation test was conducted without a supply of electric current, so the FY2022
irradiation test was conducted with a supply of electric current, but malfunctions were observed
at less than the target 1000 Gy, so the procedures for drone operations and the configuration ofelectric parts in the airframe need to be reviewed.
©International Research Institute for Nuclear Decommissioning6. Implementation details

No.89

Unit 1(2) Development of the bottom access investigation method (drone)(Supplementary material). Results of functional verification tests for FY2022 (drone)
Test (a)-⑪: [Temperature / current value verification test]
TargetDrone (wired / wireless)① Drone hovered at a height of 1 m above the floor for 1 or 2 minutes.
② Measured the temperature of the center of the airframe and the electronic components (ESC) both before and after flight. Also measured the
maximum electric current value during flight.
[Note] For reference, temperatures were measured using a thermal camera.

Test method
Output/Assessment
criteria

Change in temperature / electric current value of electronic components as output rises

Test results[Before flight]

Temperature / current value verification test (wired drone)
Temperature [°C]Electronic
Flight time Center of airframecomponents
No.
[min.](ESC)
Before[After
Before[Afterflightflight]flightflight]
1
1
19.8
23.4
21.6
48.0
2

2

21.8

28.0

20.2

56.0

Center of
airframe(27.9°C)

Center of
airframe(26.7°C)

Maximum
current
value[A][After two minutes of flight]
Motor(77.3°C)
Electronic
components(ESC)(70.2°C)

17

Measurement by thermal camera* (wired drone)[After two minutes of flight]

17

Temperature / current value verification test (wireless drone)

No.

1
2

Battery capacity

Two 4600 mAhbatteries

Temperature [°C]Electronic
Flight time Center of airframecomponents[min.](ESC)
Before[After
Before[Afterflightflight]flightflight]
1
20.6
32.0
20.0
40.0
2

21.0

36.0

20.0

46.0

Motor
(93.3°C)

Maximum
current
value
[A]
65
70

Electronic
components(ESC)(71.1°C)*Thermal camera
measurements are
for reference.

Measurement by thermal camera* (wireless drone)⚫ The thermal camera measurements revealed that the components with the highest rate of temperature rise with increasing output were the motor and theelectronic components (ESCs).
⚫ In FY2022, cooling fans were installed to make cooling of the airframe interior more efficient, but there is room to consider more efficient methods for coolingelectronic components (ESCs), which have a high rate of temperature increase.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.90(Supplementary material). Results of functional verification tests for FY2022 (drone)

Test (a)-⑫: [Waterproof performance verification test]
Target

Test method
Output/Assessment
criteria

Drone (wired / wireless)① Flew drone at a height of 1 meter.
② Sprinkled water from above the drone for 5 minutes at a rate of approximately 5 L/min using a water sprinkler.
③ After sprinkling, checked drone for operational abnormalities.
No abnormality in drone operation after sprinkling of water from above for 5 minutes [reference measurement]

Test results

Waterproof performance verification
test (wired specification)

Waterproof performance verification test
(wireless specification)⚫ No abnormalities in operation were observed after sprinkling of water.
⚫ Water pressure and dust may also have an impact, so waterproofing and dustproofing measures must be considered in the future.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.91(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)

Test (b)-①: [Tractive force verification test (1/2)]
Target

Test method

Telescopic rod transfer cart (wired specification / wireless specification)① Installed the equipment on the grating.
② Operated the crawler forward and measured the tractive force using a spring scale fixed opposite to the direction of
movement.
③ The grating was dry or wet, and oriented in three patterns: vertical, diagonal, or horizontal (0°, 45°, or 90° to the directionof movement).

Output/Assessment
Actual value of crawler cable tractive force in dry or wet conditions
criteria

Equipment
movement
direction

Orientation of grating

Crawler©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.92(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)

Test (b)-①: [Tractive force verification test (2/2)]
Test results
Tractive force verification test
Condition Angle [°]1

Wired
Wireless
specification specification

Forward

274

254

2

Backward

323

254

3

Forward303

225

Backward

274

196

Forward

303

343

0

Dry

45

4
5
90
6

Backward

7

392

294

Forward

107

147

8

Backward

107

147

9

Forward

176

196

Backward

147

98

Forward176

215

Backward

196

441

0

Wet

45

10
11

500

500

450

450

400

400

Tractive force [N]Tractive force [N]No.

Direction of
movement

Tractive force [N]Grating

350
300
250

200
150

350
300

Dry
(forward)
乾燥(前進)

250

Dry(backward)
乾燥(後進)

200

Wet(forward)
濡れ(前進)

150

Wet(backward)
濡れ(後進)

100

100

50

50

0

0
0

10 20 30 40 50 60 70 80 90

Grating angle [°]0

10 20 30 40 50 60 70 80 90

Grating angle [°]90

12Tractive force verification test (left: wired specification, right: wireless specification)⚫ The tractive force of the telescopic rod transfer cart was found to be greater in dry conditions than in wet conditions for both wired
and wireless specifications.
⚫ The minimum tractive force in these measurements was about 98 N (conditions: wireless specification / wet / 45° / backward).

©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.93(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)

Test (b)-②: [Driving performance verification test]*
Target*Wired specifications: Test (b)-② and test(c)-② were conducted simultaneously.

Telescopic rod transfer cart (wired specification / wireless specification)

Test method① The equipment made round trips on top of the grating. (The outward journey is forward and the return journey is backward.)② When maneuvering, controlled the device by camera footage only.
③ Checked maneuverability in dry and wet conditions.
[Note] Conducted as another project (mockup equipment for Detailed Investigation inside PCV)

Output/Assessment
Ability to drive the telescopic rod transfer cart on grating in dry or wet conditions without problems
criteria

Test results
Driving performance verification test
No.

Grating Direction of
condition movement

1

Maneuverability
WiredWireless
specification specification

Forward

Pass

Pass

Backward

Pass

Pass

Forward

Pass

Pass

Backward

Pass

Pass

Dry
2
3
Wet
4

Driving performance verification
test (wired specification)

Driving performance verification test
(wireless specification)⚫ Round trips were made without any problems.
⚫ However, for the wired drones there were cases of cables getting caught, so the amount of cable feeding and rewinding for thewired drones needs to be optimized.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.94(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)

Test (b)-③: [Verification test of travelling ability]*
Target*Wired specifications: Test (b)-③ and test(c)-③ were conducted simultaneously.

Telescopic rod transfer cart (wired specification / wireless specification)

Test method

Placed the mock left-behind B1 investigation equipment on the grating and verified that it could be traversed both forward andbackward.
[Note] Taking into account actual device considerations for the wired specification, the test was conducted with wired drone
cables set-up, and linked to a cable drum transfer cart.

Output/Assessment
Ability of the telescopic rod transfer cart to traverse the mock left-behind B1 investigation equipment in dry or wet conditions
criteria

Test results
Verification test of travelling ability
No.

Grating
condition

1

Travelling ability
Directionof
WiredWirelessmovement specification specification
Forward

Pass

Pass

Backward

Pass

Pass

Forward

Pass

Pass

Backward

Pass

Pass

Mockup of remaining B1
investigation equipment

Dry
2
3
Wet
4

Telescopic rodtransfer cart

Cable drumtransfer cart

Travelling ability verification
test (wired specification)

Traversing mock left-behind B1 investigationequipment (wired specification)⚫ The telescopic rod transfer cart was able to traverse the mock left-behind B1 investigation equipment in both dry and wet conditions.
⚫ To simplify the procedure assuming actual equipment, the mock left-behind B1 investigation equipment was traversed while the cable for thewired drone was fed/wound only at the telescopic rod tip. (The cable at the rear of the equipment was assisted by hand, since it’s expectedthat there will be a cable assistance device.)©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.95(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)
Test (b)-④: [Rod extension/retraction test]
Combined
Test (b)-⑤: [Passage performance verification test]
Test (b)-⑥: [Composite cable feeding/winding test (linkage with rod extension/retraction
operation)]
Test (b)-⑦: [Composite cable feeding/winding test (linkage with cable drum)]

Wired specification: Test (b)-④, ⑤, ⑥, ⑦ andTest (c)-④Wireless specification: Test (b)-④ and ⑤

Test (c)-④: [Composite cable feeding/winding test (linkage with telescopic rod)]⚫ The above five tests were conducted for each of the above combinations of wired and wireless specifications
using the following provisional procedures for actual equipment, which were determined based on
preliminary verification tests.
Rod extension/retraction: Provisional procedures for actual equipment (wired specification)
No.

During extension

During retraction

1

Extend rod by 1 m

Retract rod by 1 m

2

Feed 1 m of cable from drum transfer cart

Wind 1 m of cable with drum transfer cart

3

Extend rod by 1 m

Retract rod by 1 m

4

Feed 1 m of cable from drum transfer cart

Wind 1 m of cable with drum transfer cart

5

Extend rod by 1 m

Retract rod by 1 m

6Bring the cable back 0.5 m at the rod tip

Wind 1 m of cable with drum transfer cart

7

Extend rod by 1 m

Retract rod by 1 m

8Bring the cable back 0.5 m at the rod tip

Wind 1 m of cable with drum transfer cart

9

Extend rod by 1 m

Retract rod by 1 m

10

Feed 3 m of cable at the tip

Wind 1 m of cable with drum transfer cart

Expected arrangement of actual equipment

For the wireless system, there is no interaction with cables and only a simple extension/retraction operation,
so the procedures are not explicitly stated.

©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.96(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)[Rod extension/retraction test (1/3)]*
Target

Test method

Output/Assessment
criteria*Wired specification: Tests (b)-④, ⑤, ⑥, ⑦, and (c)-④ were conductedsimultaneously.
Wireless specification: Tests (b)-④ and ⑤ were conducted simultaneously.

Telescopic rod transfer cart (wired specification / wireless specification), cable drum transfer cart (wired specification)① Extended and retracted the telescopic rod according to the provisional procedures for actual equipment, and measured the amount of timeneeded for extension and retraction operations.
② During extension, measured the amount of bending of the telescopic rod (the distance from the floor to the center of the rod pipe) at every 1 mfrom the rear end of the equipment to the tip.
[Note]• In consideration of the actual equipment for the wired specification, the test was conducted with the cable for the wired drone connected to the rod
tip.
• The initial feed rate was set at 5 m.

•
•
•
•
•

Time needed for extension and retraction operations
The amount of bending of the telescopic rod for every meter from the rear end of the equipment to the tip (the distance from the floor to the centerof the rod pipe)
Ability to pass through the TIP guide pipe (mock-up), which is a structure inside the pedestal
Optimal initial rod angle during rod extension (see figure below)
Telescopic rod extension/retraction and linkage with cable drum during composite cable feeding/winding

Ladder edge

TIP
guide
pipe

Telescopic rod transfer cart
(wired specification)

α: Initial rod angle

Innerside ofopeningOuterside ofopening
CRD
opening

Rod extension/retraction combined test (wired specification)©International Research Institute for Nuclear Decommissioning6. Implementation details

No.97

Unit 1(2) Development of the bottom access investigation method (drone)(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)[Rod extension/retraction test (2/3)]**Wired specification: Tests (b)-④, ⑤, ⑥, ⑦, and (c)-④ were conductedsimultaneously.
Wireless specification: Tests (b)-④ and ⑤ were conducted simultaneously.

Test results (wired specification)
Rod extension/retraction combined test (wired specification)

No.

Initial rod
angle
[°]

1

11.2

2

15.3

3

14.3

Passagecapability

Distance from floor to center of rod pipe [mm]Amount of Amount
Linkage withtimeof time 1 m from 2 m from 3 m from 4 m from 5 m fromrod
needed needed the rear the rear the rear the rear the rear
extension/retr
forfor
end of the end of the end of the end of the end of theactionextension retraction
rod
rod
rod
rod
rod

4 min. 26 7 min. 53
sec.
sec.
4 min. 32 7 min. 2
Unsatisfactory
sec.
sec.
5 min. 15 7 min. 36
Satisfactory*
sec.
sec.
Pass

Linkage(Test (b)-⑥ and ⑦,
Test (c)-④)

Rod extension/retraction(Test (b)-④)

Linkage withcable drum

730

723

667

558

430

No problems

No problems

803

873

890

855

790

No problems

No problems

788

832

827

770

682

No problems

No problems*Although passable, the cable of the pan-tilt camera at the end of the rod came in contact with the TIP guide tube.

Initialangle: 15.3°
初期角度:15.3°

Initial angle: 14.3°
初期角度:14.3°

Distance from floor to center of rod
pipe [mm]Passability(Test (b)-⑤)

Initial angle: 11.2°
初期角度:11.2°

1200
1000
800
600
400
200
0
0

1

2

3

4

5

6

Distance from rear end of rod [m]Bending during rod extension/retraction⚫ The optimal initial angle at which the rod can pass through the TIP guide tube (mock-up), which is a structure inside the pedestal, is considered tobe the angle at which the rod tip is highest after extension, making it easier to check conditions in the upper part of the pedestal, and this angle wasconfirmed to be 14.3°.
⚫ In addition, the time needed for extension/retraction at said initial angle was; extension: 5 min. 15 sec. / retraction: 7 min. 36 sec.
⚫ The difference in the amount of bending between the highest and lowest points was approximately 150 mm.
⚫ There were no problems with rod extension/retraction and linkage with the cable drum during composite cable feeding/winding, and 7 m of cable
could be fed/rewound by feeding the cable at the rod tip. However, the wired drone composite cable that had become loose during rod extension
got caught on the structure, so the provisional procedures for actual equipment need to be revised.

©International Research Institute for Nuclear Decommissioning6. Implementation details

No.98

Unit 1(2) Development of the bottom access investigation method (drone)(Supplemental explanatory material) Results of functional verification tests for FY2022 (telescopic rod transfer cart)[Rod extension/retraction test (3/3)]**Wired specification: Tests (b)-④, ⑤, ⑥, ⑦, and (c)-④ were conductedsimultaneously.
Wireless specification: Tests (b)-④ and ⑤ were conducted simultaneously.

Test results (wireless specifications)No.

Initial rod
angle
[°]

Passing
performance(Test (b)-⑤)

Rod extension/retraction(Test (b)-④)

Passagecapability

Distance from floor to center of rod pipe [mm]Amount of Amount of
1 m from
2 m from
3 m from
4 m from
5 m from
time
time
the
rear
the
rear
the
rear
the
rear
the rearneeded for needed forextension retraction end of the end of the end of the end of the end of the
rod
rod
rod
rod
rod

1

10.8

Pass

2

15.3

Unsatisfactory

3

14.1

Unsatisfactory

4

12.1

Pass

3 min. 58 6 min. 54
sec.
sec.
19 min. 28 11 min. 23
sec.
sec.
7 min. 45 8 min. 21
sec.
sec.
6 min. 6
7 min. 37
sec.
sec.

748

750

709

617

495

843

948

1005

1010

987

805

870

894

861

795

775

805

782

710

620

Distance from floor to center of rod pipe[mm]

Rod extension/retraction combined test (wireless specification)

Initialangle: 10.8°
初期角度:10.8°

Initialangle: 15.3°
初期角度:15.3°

Initialangle: 14.1°
初期角度:14.3°

Initialangle: 12.1°
初期角度:12.1°

0

3

1200
1000
800
600
400
200
0
1

2

4

5

6

Distance from rear end of rod [m]Bending during rod extension/retraction⚫ The optimal initial angle at which the rod can pass through the TIP guide tube (mock-up), which is a structure inside the pedestal, is considered tobe the angle at which the rod tip is highest after extension, making it easier to check conditions in the upper part of the pedestal, and this angle wasconfirmed to be 12.1°.
⚫ The initial angle is smaller than for the wired specification because there are no cables.
⚫ In addition, the time needed for extension/retraction at said initial angle was; extension: 6 min. 6 sec. / retraction: 7 min. 37 sec.
⚫ The difference in the amount of bending between the highest and lowest points was approximately 185 mm.

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.99(Supplementary material). Results of functional verification tests for FY2022 (cable drum transfer cart)

Test (c)-①: [Tractive force verification test]

Test method

Output/Assessment
criteria

Cable drum transfer cart (wired specification)① Installed the equipment on the grating.
② Operated the crawler forward and measured the tractive force using a spring scale fixed
opposite to the direction of movement.
③ The grating was dry or wet, and oriented in three patterns: vertical, diagonal, or horizontal (0°,45°, or 90° to the direction of movement) (see figure on the right).

Equipment
movement direction

90°

45°

0°

Actual value of crawler cable tractive force in dry or wet conditions

Test results⚫ For grating angles of 0° and 90°, the tractive
force of the cable drum transfer cart was greaterin the dry condition than in the wet condition,
regardless of the direction of movement.
⚫ There was no significant difference in tractive
force between wet and dry when the grating angle
was 45°.
⚫ The minimum tractive force in thesemeasurements was about 215 N (conditions: wet /90° / forward).

Tractive force verification test
500

Direction
Tractive forceof[N]
Condition Angle [°] movement
Grating

No.
1

0

2
3
4

Dry

5

90

6
7

0

8
9

10
11
12

45

Wet

45

90

450

400

Forward303

Backward

294

Forward254

Backward

284

Forward392

Backward

343

100

Forward264

50

Backward

245

0Forward245

Backward

274

Forward215

Backward

294

Tractive force [N]Target

350
300

Dry
(forward)
乾燥(前進)

250

乾燥(後進)
Dry(backward)

200

濡れ(前進)
Wet(forward)150

濡れ(後進)
Wet(backward)

0 10 20 30 40 50 60 70 80 90

Grating angle [°]Tractive force verification test

©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.100(Supplementary material). Results of functional verification tests for FY2022 (cable drum transfer cart)

Test (c)-②: [Driving performance verification test]*
Target

Test method*Wired specifications: Test (b)-② and test (c)-② wereconducted simultaneously.

Cable drum transfer cart (wired specification)① The equipment made round trips on top of the grating. (The outward journey is forward and the return journey is backward.)② When maneuvering, controlled the device by camera footage only.
③ Checked maneuverability in dry and wet conditions.
[Note] Conducted as another project (mockup equipment for Detailed Investigation inside PCV)

Output/Assessment
Ability of the cable drum transfer cart to move on top of grating in dry or wet conditions without any problems
criteria

Test results
Driving performance verification test
No.

Grating Direction of
condition movement

1

Maneuverability

Forward

Pass

Pass

Backward

Pass

Pass

Forward

Pass

Pass

Backward

Pass

Pass

Dry
2

3
Wet
4

Driving performance verification test

⚫ Round trips were made without any problems.
⚫ However, there were cases of wired drone cables getting tread upon, so the amount of cable feeding and rewinding for the wired
drones needs to be optimized.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.101(Supplementary material). Results of functional verification tests for FY2022 (cable drum transfer cart)

Test (c)-③: [Verification test of travelling ability]*
Target*Test (b)-③ and Test (c)-③ were conductedsimultaneously.

Cable drum transfer cart (wired specification)

Test method

Placed the mock left-behind B1 investigation equipment on the grating and verified that it could be traversed both forward andbackward.

Output/Assessment
Ability of the telescopic rod transfer cart to traverse the mock left-behind B1 investigation equipment in dry or wet conditions
criteria

Test results
No.

Grating
condition

1

Verification test of travelling
ability
Direction of
movement

Mockup of remaining B1
investigation equipment

Travelling ability
WiredWireless
specification specification

Forward

Pass

Pass

Backward

Pass

Pass

Forward

Pass

Pass

Backward

Satisfactory
(*)

Pass

Telescopic rodtransfer cart

Dry
2
3
Wet
4

(*) When the cable drum transfer cart was moved backward to traverse
the B1 investigation equipment, the part that clamped the cable at therear of the equipment and protruded beyond the diagonal guide parts
sometimes interfered with the mock left-behind B1 investigationequipment and prevented the cart from traversing the equipment.

Cable drumtransfer cart

Verification test of travelling ability (wired specification)⚫ The cable drum transfer cart was able to traverse the mock left-behind B1 investigation equipment in both dry and wet conditions. However, the ease of traversing varied
depending on the condition of the cable and the condition of the mock left-behind B1 investigation equipment. This must be reviewed in more detail in future combined tests inorder to respond to various situations in application of actual equipment.
⚫ All cameras mounted on the cable drum transfer cart were fixed cameras. Since it is difficult to check the cables during movement, a pan-tilt camera should be used in the actual
equipment, and the design should be improved to allow checking of cables.
⚫ To simplify the procedure assuming actual equipment, the mock left-behind B1 investigation equipment was traversed while the cable for the wired drone was fed/wound only at
the telescopic rod tip.
(The cable at the rear of the equipment was assisted by hand, since it’s expected that there will be a cable assistance device.)©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.102(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-①: [Tractive force verification test]
TargetCable assistance device (wired specification / wireless specification)

Test results

Tractive force verification test
① Installed the equipment on the grating.
② Operated the crawler forward and measured the tractive force with
Test method
a force gauge fixed opposite to the direction of movement.
③ Repeated the process with vertical, horizontal, or diagonal gratingorientations and under wet or not wet conditions.
Output/Assessment Actual value of crawler cable tractive force (Target: 100 N)
criteria

Grating orientation: vertical

Grating orientation: diagonal

Grating orientation: horizontal

Direction of movement

No.

Grating
Grate

Wetting

Tractive force[N]

1

Vertical210

2

Horizontal

3

Diagonal

190

4

Vertical

190

5

Horizontal

6

Diagonal

No

Yes

250

230

180

Direction of movement

Direction of
movement⚫ In all conditions, the target tractive force of 100 N
was exceeded.
⚫ Tractive force was strongest when the gratingorientation was horizontal, and about 20 to 30%
weaker when vertical or diagonal.
⚫ Tractive force was about 10% weaker when thegrating was wetted versus when not wetted.

Force gauge

Conceptual drawing of the test
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Unit 1

No.103(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-②: [Driving performance verification test (1/2)]
Target

Test method

Cable assistance device (wired specification / wireless specification)① Performed crawler operations along the access route on the grating, made round trips on the access route.
Guide pipe
② The grating was either dry or wet.

Output/Ability to make round trips between the deployment point on the grating and the vicinity of the B1 investigation
Assessment
equipment without problems in dry or wet conditions.
criteria
Guide pipe
X-2 Pene
Deployment
point

Vicinity of B1
investigation equipment

Access route

Conceptual drawing ofaccess route

Conceptual drawing of the test
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.104(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-②: [Driving performance verification test (2/2)]

Test results⚫ Round trips were made without any problems.
⚫ It was confirmed that a 2-cable pushing maneuver is possible.
⚫ When two cables were vertically aligned on one side of the B1 investigation equipment, the device by itself
could not free the cables in a lateral direction.
⚫ However, it may be possible to free cables if there is linkage to other equipment (drum transfer cart).

Maneuvering toward the B1 remnant

Freeing a cable overlap
Cable pushing maneuver©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.105(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-③: [Cable grabbing performance verification test]
TargetTest
methodCable assistance device (wired specification / wirelessspecification)

Cable grabbing performance verification test

① Laid Φ40 mm mock composite cables on both sides (leftand right) of the cable assistance device.
② Checked whether the feed rollers can grip the cables for
operations in each axis.
③ Checked to see if the camera footage can be used toassess gripping of cables.

Output/Ability to grip the composite cables that are spread acrossAssessment the grating on the left and right sides of the equipment, andcriteria
ability to assess gripping of cables via camera footage

Test
results

Cable placement

Grab abilityVideoverifiability

Left side

Pass

Pass

Right side

Pass

Pass

⚫ The ability to grip the composite cables on the left
and right sides of the equipment was confirmed.
⚫ Although difficult, by raising and lowering thecamera, it was possible to assess gripping of cables
via camera footage.

Φ19 camera

Feed roller

Mock composite
cablesConceptual drawing of grippingof left side cable

Conceptual drawing of gripping ofright side cable

Conceptual drawing of cableassistance device before operation

Conceptual drawing of the test
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.106(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-④: [Cable feed force verification test (1/2)]
TargetCable assistance device (wired specification / wireless specification)① Laid Φ40 mm mock composite cables on both sides (left and right) of the cable assistance device.
② Gripped one of the cables with the feed roller.
Test method ③ Fed cable and measured the feed force using a force gauge fixed in the direction opposite to cable feeding.
④ Repeated ② and ③ under both wet and dry conditions for each cable gripping position.
⑤ Measured the cable clamping pressure and cable feed rate under each condition.
Output/Cable feed performance (cable feed force*/ speed / clamping force)
Assessment*Target feed force: 100 N
criteria
Force gauge

Mock composite cables

Feed roller

Conceptual drawing of grippingof left side cable

Conceptual drawing of gripping ofright side cable

Conceptual drawing of the test
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.107(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-④: [Cable feed force verification test (2/2)]
Test results

Cable feed force verification test
Cable

Gripping
position

Wetting

Left sideNo

Right side

Feed force
[N]
112

118

Left side

123

Right side

114

Right side

Yes

Clampingpressure[MPa]

Feed speed[mm/s]

0.4

0.4

132

0.3

Right side

180

0.2

Right side

150

0.1

12.5

Measurement of feed force

Cable feed force verification test (sand adhesion condition)
Cable
Gripping
positionSandadhesion

Right side

Yes

Feed force[N]

Clampingpressure[MPa]

Feed speed[mm/s]

168

0.2

12.5

Zeolite Z-13

Cable after
application of sand

⚫ In all conditions, the target feed force of 100 N was exceeded.
⚫ Table 1 shows that neither cable gripping position nor wetness had a significant effect on feed force. Furthermore, the clamping pressure with maximum
feed force was 0.2 MPa.
⚫ An additional feed test with sand(*) adhered to the cable was conducted and cable feeding was possible without any problems.
(*)Sand specifications: Powdered zeolite Z-13.
⚫ The equipment exhibited backward movement behavior during cable feeding, but it was possible to compensate by (on the spot gripping) maneuvering
the crawler.
©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.108(Supplementary material). Results of functional verification tests for FY2022 (cable assistance device)

Test (d)-⑤: [Rollover verification test]
TargetCable assistance device (wired specification / wireless specification)① Installed cable assistance device on the grating.
② Performed operations in each axis and checked whether there
Test method
was a risk of rolling over.
③ Checked whether the device can recover after rolling over.

Test
results⚫ The device traversed the Φ40 cable in aconfiguration prone to rolling (conceptual
drawing of test ①), but did not tip over.
⚫ Even if the device tipped over, if it tippedover at 90° or less, it could recover using
the sliding mechanism.

Output/• No risk of cable assistance device rolling over in each operation
Assessment• Ability to recover after rolling overcriteria
Conceptual drawing ofrollover angle and recovery

Center ofgravity

Tipped (approx. 90°)

Activation ofslide mechanism
Configuration prone
to tipping

TippedRecovery①②③Conceptual drawing of the test

After recovery©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.109(Supplementary material). Results of functional verification tests for FY2022 (350A installationequipment)
Test (e)-①: [Bending load verification test (1/2)]
TargetInstallation equipment (wired specification / wireless specification)①
Test method ②③

Placed equipment (40 kg) on the scoop section.
Turned the bending pole and verified that bending operations were possible.
Measured the maximum load torque of the bending pole.

Output/Assessment Bending ability with the weight of the investigation equipment (45 kg) on the scoop section.
criteria
Conceptual drawing of pivot pole load torquemeasurement

45 kg weight

Pivot pole

Force gauge

Conceptual drawing
of bending operation

Bending
operation
Direction of action

Conceptual drawing of the test
©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.110(Supplementary material). Results of functional verification tests for FY2022 (350A installationequipment)
Test (e)-①: [Bending load verification test (2/2)]
Test results⚫ Bending movement with a 45kg load was possible.
⚫ An additional test with 65 kg was conducted and there were no problems withbending operations.
⚫ The force on the pole was greatest when the bending angle was 10°.
Fulcrum

Bending load verification test
Bendingangle[°]

Maximum load
torque
[N⋅m]

1

0

5.4

2

10

6.6

3

20

5.8

4

30

5.0

40

4.6

50

4.2

7

60

3.6

8

70

2.6

9

80

2.4

10

90

1.4

11

0

7.4

10

8.4

20

6.8

Weight/s
No.
[kg]

5
6

12
13

45

65

Center ofgravityDuring testing

Lead

With 45 kg load

With 65 kg load©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.111(Supplementary material). Results of functional verification tests for FY2022 (350A installationequipment)
Test (e)-②: [Cable feed force verification test (1/2)]
TargetInstallation equipment (wired specification / wireless specification)①②
Test method ③④⑤

Clamped the mock composite cables with the extrusion rollers of the installation equipment.
Turned the extruder pole and measured the extrusion force using a force gauge fixed opposite to the direction of extrusion.
Measured the maximum load torque of the extruder pole.
Measured cable clamping pressure.
Repeated the process for the conditions of left vs. right extrusion roller, composite cable diameter, and wetness.

Output/Assessment Cable feed performance (cable feed force / speed / clamping force)
criteria
Conceptual drawing of extruder pole load
torque measurement

Force gauge

Mock composite cables

Extrusion rollers

Extruder poles

Conceptual drawing ofcable extrusion

Force gauge

Conceptual drawing of the test
©International Research Institute for Nuclear Decommissioning6. Implementation details

Unit 1(2) Development of the bottom access investigation method (drone)

No.112(Supplementary material). Results of functional verification tests for FY2022 (350A installationequipment)
Test (e)-②: [Cable feed force verification test (2/2)]
Test results⚫ The test results show that the optimum clamping pressure is 0.3 MPa.
⚫ The target feed force of 100 N was exceeded for both Φ40 mm and Φ10 mm cables.
⚫ There was no difference in feed force between the left and right extrusion rollers, andthere were no changes caused by conditions of wetness.
⚫ The extrusion rollers need to be modified in order to firmly clamp Φ10 mm cables.
⚫ Improvements are needed as the cables are not easy to install and remove.

Roller wrappedwith tapeΦ9.5 mm mock cable

Cable feed force verification test
Cable
No.

Cable used

Gripping
position

Wetting

Feed
force
[N]

Clampingpressure[MPa]

1

Right side

75

0.1

2

Right side

73

0.2

84

0.3

50

0.4

3

Φ40 mmRight sideNo

Maximumload torque
[N⋅m]

7.0

Investigate optimalclamping pressure

The cable was smaller
in diameter than
expected and could not
be clamped firmly, so
there was no change infeeding force.

4

Right side

5

Left side

8

0.1

0.4

6

Left side

10

0.2

1.0

10

0.3

1.0

10

0.4

1.0

7

Φ9.5 mm

Left side

8

Left side9

Left side

10

Right side11

Φ40 mmLeft side

12

Right side

13

Right side

14
15
16
17

Φ9.5 mm
Φ9.5 mm(Wrapped withtire tape)

Right side
Left side

No

No

Yes

7.0

80

7.0

89

7.0

170
Yes

Left side
Left side

87

100

No

Remarks

Feed roller

Φ40 mm mock cable

9.0
0.3

Roller wrapped with tape

14.0

10

0.6

9

0.8

100

6.8

168

8.8

Conducted by clampingwith tape wrappedaround the rollers

Space is tight and cableinstallation is difficult.
Installing Φ40 cable©International Research Institute for Nuclear Decommissioning6. Implementation details(2) Development of the bottom access investigation method (drone)

Unit 1

No.113(Supplementary material). Results of functional verification tests for FY2022 (350A installationequipment)
Test (e)-③: [Cable feeding operations verification test]
TargetInstallation equipment (wired specification / wireless specification)① Clamped the mock composite cables on the left and right sides of
the installation equipment with the extrusion rollers on the left andTest method
right sides, respectively.
② Turned the extruder poles and checked the ease of feeding two
cables (Φ40 mm, Φ10 mm).

Test results⚫ The ability to extrude two cables was confirmed.
⚫ When bending the scoop, there were incidents where
the cables got caught at the base of the scoop.
⚫ The cable deviation prevention plate needs to bemodified to prevent the cables from getting caught.

Output/Assessment Ability to feed two cables at the same time without difficulty
criteria
Mock Φ40 mm cable
Mock Φ9.5 mm composite cable
Place where cables
got caught
Extrusion rollers

Cable deviation
prevention plate
Mock Φ40 mm composite
cable

Conceptual drawing of 2-cable
extrusion

Conceptual drawing of the test
©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.114(2) Development of the bottom access investigation method (telescopic pipe)<Implementation details up to FY2021>
Prototype telescopic access equipment with a total of 14 stages was manufactured as the bottom
access investigation method for Units 2 and 3, and elemental tests were conducted. The function oftelescopic access equipment was evaluated as feasible.
<Summary of implementation in FY2022>
Review the development plan based on the results of elemental tests conducted in FY2021, andproceed with study of each of the issues identified.

<Implementation details for FY2022>- Review the development plan and identify issues based on the results of elemental tests
conducted in FY2021- Examination of proposed countermeasures to address issues- Study of test plans to confirm proposed countermeasures and their effects- Test to verify the effects of countermeasures

Note: Terms used in this document are defined as follows.
- Telescopic access equipment: A complete set of equipment consisting of telescopic pipes, winders,investigation equipment, etc.
- Telescopic pipe: A telescopic pipe forming a component of the above equipment©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.115(2) Development of the bottom access investigation method (telescopic pipe)
1) Summary of FY2021 results (1/2)- Conceptual design and elemental tests were conducted to address development issues, including
studies on interfacing with arm-type access equipment.
- A study was conducted on countermeasures to the issues of high leakage and sliding resistance atthe sealing section identified in a simplified test conducted in FY2020 using a 3-stage telescopic
pipe. Improvements to the roughness of the pipe’s inner surface were reflected in the device
specifications. A simplified test using a 3-stage telescopic pipe was conducted and verified theeffects of the proposed countermeasures.
Camera tip

Approx.
8m

Upper surface ofgrating

Drawing of access using telescopic pipe

Full retraction

Full extension

Simplified test using a 3-stage telescopic pipe

©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.116(2) Development of the bottom access investigation method (telescopic pipe)
1) Summary of FY2021 results (2/2)- Elemental tests were conducted to evaluate the feasibility of the full 14-stage access equipment.
The function of telescopic access equipment was evaluated as feasible.

Full extension
During retraction

2nd stage extension©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.117(2) Development of the bottom access investigation method (telescopic pipe)2) Steps of “conceptual study of bottom access and investigation equipment”

FY2020① Formulation of bottom access/investigation
plan and development plan foraccess/investigation equipment
Drafting of investigation plan
(Examination of applicabletechnologies)

FY2021

FY2022② Conceptual study of bottom accessand investigation equipment<Conceptual design / Elemental testing>③ Conceptual study of bottom accessand investigation equipment

Drafting of development plan
(Review of development
issues)(a) Factor analysis of issues(b) Examination of proposed
countermeasures
Drafting of development plan
(Identification ofdevelopment issues)

Implementation of simplified
tests

Examination of proposed
countermeasures to addressdevelopment issues(c) Tests to verify the effects
of proposed countermeasures

Tests to verify the effects ofproposed countermeasures(d) Conceptual study andsimplified tests fordevelopment issues(e) Feasibility testing using a
14-stage telescopic pipe

Practicability evaluation(Identification of new issues)

Investigation anddevelopment planning

Feasibility evaluation(The function of telescopic
access equipment)(f) Feasibility evaluation(The function of telescopic
access equipment)

Items covered in this document

Determination of the method©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.118(2) Development of the bottom access investigation method (telescopic pipe)
3) Review of development plans (development issues and action policies)

No.

1

2

Major items

Intermediate
items

Minor items

Development issues- Tip positioning accuracy
Verification of detailed- Arm deflection/oscillation
Verification of specifications of arm-type - Range of motion in each axis
Equipment for connection
retrieval access- Transportable weightaccessing the with the arm- equipment- Arm external cable specifications
inside of the type retrieval- Emergency action policy
pedestal
accessVerification of attachment - Verification of feasibility of procedures/transport casks forequipment
and detachment method,transfer in and out of the enclosure
specifications- Methods of attachment and removal using Dexter

Examination of basic
structure3- Structural feasibility under the dimensional constraints
imposed by use of arm-type retrieval access equipment

FY2022 action policy

FY2022 test/action items- Check the “Gradually Increasing the Scale ofRetrieval” project for information conducive Gather information from other projects
to the study of equipment specifications- Check the “Gradually Increasing the Scale ofRetrieval” project for information conducive Gather information from other projects
to the study of equipment specifications- Verification of bonding strength assuming acylindrical pipe shape
Bonded section strength verification test
- Verification of fabricability of aluminum pipes, Partial fabrication of aluminum pipes
an alternative design for the telescopic pipe

- Joint connection accuracy (pipe tilt)

4
Accessequipment
Telescopic
from inside the accesspedestal toequipment
inside thedesignRPV

Understanding
extension/retraction
behavior- Swaying during extension (investigation equipment section) - Control of tilt behavior in the direction of theanti-rotation rails during telescopic pipe
- Amount of tip deviation (looseness/deflection) duringextension
vertical extension- Control of looseness due to gaps between- Verification of extension/retraction behavior when telescopic pipes, prevention of tilting caused by gaps
during emergency retraction (inpipe is tilted
emergencies)- Verification of extension/retraction motion when snagging- Evaluation of telescopic pipe behavior whenoccurs (check extension possible when telescopic pipe
the arm-type retrieval access equipment
snagged and retraction possible when investigationsways
equipment snagged)

Desk study
14-stage operation verification test

- Effects of adhered matter on extension/retraction behavior- Required air pressure during extension- Positioning control

5

Understanding uniquecharacteristics ofextension/retraction
operations- Sliding resistance between air gasket and telescopic pipe
- Design study

Desk study
14-stage operation verification test

- Sliding resistance of telescopic pipe rotation control guide©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.119(2) Development of the bottom access investigation method (telescopic pipe)
3) Review of development plans (development issues and action policies)No.

Major items

Intermediate
items

Minor items

Development issues

FY2022 action policy

FY2022 test/action items- Accuracy of wire tensile force measurement (whether slack
can be detected)- Coordinated control of cable winding force and air pressureduring extension/retraction of telescopic pipe

6

AccessTelescopic
equipment
accessfrom inside theequipmentpedestal todesigninside the RPVDesign of cable winding- Limit detection
mechanism- Pressure-resistant box design (approx. 0.1 MPa)
- Mechanical arrangement (X6 Penetration passage, arminterference)

Exterior design of- X6 Pene, interference with reactor internals
investigation equipment- Diameter reduction (target: Φ6 or less)
Cable design- Tensile strength89Noise reduction method - Noise during rotation when using slip rings (dosimeter)
10 Investigationequipment
11

Investigationequipment
Measures to prevent
designmatter adhering tocameras and lights

Visibility
12

13

Posture control mechanism operation- Test manufacturing and evaluation of postureverification test
control mechanism
14-stage operation verification test
- Design study

Desk study- Design study

Desk study- Design study- Evaluation of noise caused by investigationequipment to dosimeter

Evaluation of noise caused byinvestigation equipment- Effects of water droplets and adhered matter, etc. on camera- Design study
and lights- Verification of long-distance visibility when there ismachinery/structures near the camera (halation problem)- Understanding characteristics of vision quality loss due tonoise caused by radiation dose

Desk study- Impact assessment of cumulative dose on
CMOS camera irradiation test
video image due to CMOS camera irradiation

Operability- Evaluation of whether or not telescopic pipe
passage clearance and extension length canbe determined using the fixed-point camera- Whether the camera on the investigation equipment and theat the tip of the arm-type retrieval accesscamera on the wrist section can determine the operational
equipment
Study of equipment operation
Operability with camera
situation, such as contact with a structure, and operation can - Evaluation of investigation equipment
procedures using simulations
be performed
camera’s ability to determine whether an
opening can be passed through, andwhether it can determine the direction ofcorrection of telescopic pipe posture

Emergency
response- Response to power cutoff (disconnection, etc.), control failure
Examination of items to(software excursion), control line disconnection, etc.
be expected in case of- Evaluation of behavior during earthquakes- What kind of events, such as seismic activities andemergency
blackouts, should be expected?

Others14

Desk study- Mechanical arrangement (X6 Penetration passage, arminterference)

Design of postureadjustment mechanism

7- Ensuring uniform drive torque for cable
winding drums (reduction of cable tensile
force loss)

14-stage operation verification test

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.120(2) Development of the bottom access investigation method (telescopic pipe)4) Details of implementation for FY2022 (1/3): Items related to element verification① Verification of bonding strength assuming cylindrical pipe shape- In FY2021, a bonding strength verification test was conducted on flat plates, and it was evaluated that there would be no shear failure
stress degradation in the bonded section within 72 hours under the expected environment.
- In FY2022, tests will be conducted to confirm adhesive strength in cylindrical shapes (test methods, etc., to be determined upon
consultation with partner manufacturers).
⇒ Evaluated as having the necessary strength for equipment operation. (No.123 to 128)
② Verification of fabricability of aluminum pipes, an alternative design for the telescopic pipe
- In FY2021, a test manufacturing and evaluation of the top three stages (stages 12 to 14) of aluminum pipe showed that the 13th stage
warped by about 0.3 mm and could not be retracted inside the 12th stage pipe, which presented a challenge in terms of fabricability.
- In FY2022, a further test manufacture of an aluminum pipe with 3 stages at the tip / 3 breaks at the base was conducted to address
the above issue, and the fabricability of the aluminum pipe will be re-evaluated. If there are prospects for fabricability, alternatives will
be reexamined.
⇒ Determined that manufacture of aluminum pipes is possible (No.129 to 132)
③ Evaluation of noise caused by investigation equipment to dosimeter- In FY2021, as a noise evaluation of the slip rings, an evaluation of the noise caused to the dosimeter due to cable drum drive motor
operation was conducted, and found to be negligible.
- In FY2022, an evaluation of the noise caused to the dosimeter when combined with the investigation equipment will be conducted.
⇒ Determined that noise is present but can be counteracted. (No.133 and 134)
④ Impact assessment of cumulative dose on video image due to CMOS camera irradiation- In FY2021, the vision quality of the CMOS camera was checked as part of the camera vision quality evaluation, and it was confirmedthat there was no difference in vision quality between the CMOS camera and the CCD camera.
However, it was confirmed that after irradiation, the video image was disturbed in low light intensity.
- In FY2022, another irradiation test of the CMOS camera will be conducted to confirm the accumulated dose at which the video image
disturbing event occurs.
⇒ Confirmed that video image disturbance occurs at 1440 Gy and video stops at 1584 Gy to 2060 Gy. (No.135 to 139)

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.121(2) Development of the bottom access investigation method (telescopic pipe)4) Details of implementation for FY2022 (2/3): Items related to operations⑤ Evaluation of whether or not telescopic pipe passage clearance and extension length can be determined using the fixed-point
camera at the tip of the arm-type retrieval access equipment⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through, and whether it candetermine the direction of correction of telescopic pipe posture(No.140 to 149)
- In FY2021, a simulator was used to simultaneously acquire two simulated video images (object display and overhead view from afixed point) from a camera mounted on the arm-type access equipment for retrieval (fixed-point camera) and a camera mounted on theinvestigation equipment (moving camera).
- In FY2022, a simulator will be used to check the field of view of the fixed-point camera and investigation equipment camera when thetelescopic pipe is retracted/extended and when it is tilted, and to study the operation method of the entire system.

©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3 No.122(2) Development of the bottom access investigation method (telescopic pipe)4) Details of implementation for FY2022 (3/3): Items related to combined testing of the telescopic access equipment⑦ Control of tilt behavior in the direction of the anti-rotation rails during telescopic pipe extension (No.150 to 156)
⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during emergency retraction (in emergencies)(No.157 to 170)
- In FY2021, on the basis of elemental testing using a 14-stage telescopic pipe, the function of telescopic access equipment was evaluated as
feasible.
However, it was confirmed that the telescopic pipe tends to tilt in the direction of the anti-rotation rails located to the sides as it is extended, that iflooseness between the pipe sections is unbalanced in one direction, the tip deviation of the telescopic pipe is +144.7 to -218.3 mm (the direction
where the anti-rotation rail of the telescopic pipe is fixed is negative), and that during emergency retraction, when the pipe internal pressure is
reduced from the fully extended state, the telescopic pipe gradually tilts, and the 14th stage at the tip titles at least 5.5 degrees.
- In FY2022, after implementing countermeasures (e.g., changing the arrangement of the anti-rotation rails, reviewing components, etc.) to address
the above issues, elemental tests of the 14-stage telescopic pipe will be conducted again to evaluate the effectiveness of the countermeasures.
⑨ Test manufacturing and evaluation of posture control mechanism (No.171 to 173)
- In FY2021, an outline design of the posture control mechanism was conducted.
- In FY2022, a prototype posture control mechanism will be manufactured and elemental tests will be conducted in combination with the 14-stage
telescopic pipe to evaluate feasibility.
⑩ Ensuring uniform drive torque for cable winding drums (reduction of cable tensile force loss)- In FY2021, in an elemental test of the 14-stage telescopic pipe, it was confirmed that the cable tensile force (motor drive torque) fluctuatedsignificantly in a short period of time and that the drive load may not be uniform due to imprecise assembly of the gears and drive shaft.
- In FY2022, after implementing measures to address the above issues, elemental tests of the 14-stage telescopic pipe will be conducted again toevaluate the effectiveness of the countermeasures.
⇒ Improvements were made and the countermeasures were evaluated as effective. (No.174 and 175)
⑪ Evaluation of telescopic pipe behavior when the arm-type retrieval access equipment sways- In FY2021, the rigidity of the telescopic pipe against horizontal loads was confirmed, but no evaluation of the telescopic pipe’s behavior when thearm-type access equipment sways was conducted.
- In FY2022, the natural frequency of the 14-stage telescopic pipe will be measured to confirm that it does not resonate when combined with thearm-type access equipment. In addition, the behavior of the 14-stage telescopic pipe when it sways will be confirmed by using the posture control
mechanism scheduled to undergo test manufacturing.
⇒ Measure sway period. (No.187 and 188)

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.123(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ① Verification of adhesive strength assuming cylindrical pipe shape○ Background- For the bonding strength evaluation in FY2021, a bonded section fracture test was conducted on flat plates withreference to ISO.
- However, the bonding of the telescopic sections is at the cylindrically-shaped part, so tests will be conducted tocheck bonding strength on the cylindrical components.
3. Lower pipe / top ring
Top ring

Collar Piston

The red line is the bonding point.
Rail
Lower pipe

4. Lower pipe / top ring

Upper pipe

1. Upper pipe / piston
2. Upper pipe / collar
Configuration○ Shear failure state○ Test system

Pushing jig(SKDII)

Test method

Test piece

Aluminum(A5056:
assumed top ring)

Bonding
fracturesurface

CFRP pipe

BondingsurfaceTension direction

Testing machine chuck

Receiving jig(S50C)

Shear failure test results after 24 hours
of exposure at 7200 Gy of cumulative
irradiation, 50°C, and 95% humidity

Testing system for FY2021

Testing system for FY2022©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.124(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ① Verification of adhesive strength assuming cylindrical pipe shape○ Test plan study: Influence of pipe shape (diameter: bond width)- For the 14-stage telescopic pipe, the bonding area differs for each stage where bonding is used, from amaximum inner diameter of Φ90 (2nd stage) to a minimum inner diameter of Φ30 (14th stage). Since thebonding strength depends on the bonding area, the bond length (lap length) and the bond width (pipe diameter)
were examined.
- The results from the aluminum plate test piece confirmed that the bond strength depends on the bond length(lap length) and is not affected by the bond width (pipe diameter) (based on reference data from a partnercompany).
Bonding strength evaluation is performed under two conditions: maximum inner diameter Φ90 (2nd stage) and minimum innerdiameter Φ30 (14th stage).
Lap length: 12.5 mm

Lap length: 5 mm

Load (displacement)

Converted adhesivestrength (MPa)LaplengthStressobservation
direction
Bonding agent

Bond width: 18 mm

Converted adhesivestrength (MPa)

WidthConverted adhesivestrength (MPa)Aluminum

Aluminum

Lap length (mm)Fixation

Test with constant bond width and varying lap length

Bond width (mm)Bond width (mm)Test with constant lap length and varying bond width©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.125(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ① Verification of adhesive strength assuming cylindrical pipe shape○ Test plan study: Pipe shape bonding evaluation proposal

2nd stage pipe
14th stage pipe
Pipe outer diameter: Φ32

Pipe outer diameter: Φ92

Aluminum part
(assumed top ring)

Note: 1st stage is aluminum pipe with no bonded section©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.126(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ① Verification of adhesive strength assuming cylindrical pipe shape○ Test plan study: Stress analysis of bonded parts- Stress analysis was conducted of bonded parts in the 2nd and 14th stages.
- The strength of the CFRP pipe/aluminum parts is stronger than the maximum stress of the adhesive material of
30.2 MPa (result of previous fiscal years), so it was evaluated that the adhesive strength can be evaluated.

Pushing jig Protruding
sectiondiameter

Φ29.9

Outer
diameter

Φ31.4

Inner
diameter

Φ30

Outer
diameterΦ32

Wallthickness

1

Bondinglayer

Thickness

0.15

Receivingjig

Hole
diameter

Φ32.8

Pipe

Load 12.3 kN

Pushing jig Protruding
sectiondiameter

Bonding agent
stress distribution
Maximum
stress 30.0
MPa

Aluminum stress distribution

Maximum stress32.7 MPa

The maximum stress generated is 32.7
MPa compared to the A5056 proof stressof 150 MPa, so bonding strength can bemeasured without any problem with thistest piece shapeOuter
diameter

Φ31.4

Inner
diameter

Φ30

Outer
diameterΦ32

Wallthickness

1

Bondinglayer

Thickness

0.15

Receivingjig

Hole
diameter

Φ32.8

Pipe

CFRP pipe stress distribution

Maximum
stress 109.8
MPa

The maximum stress generated is 109.8
MPa compared to the CFRP strength of
603 MPa, so bonding strength can bemeasured without any problem with thistest piece shape

Stress analysis results for the 2nd stage

Φ29.9

Bonding agent
stress distribution

Load 6.4 kN

Maximum
stress 30.2
MPa
Aluminum stress distribution

Maximum stress 33.7 MPa

CFRP pipe stress distribution

Maximum stress 96.4 MPa

The maximum stress generated is 33.7
The maximum stress generated is 96.4
MPa compared to the A5056 proof stress MPa compared to the CFRP strength ofof 150 MPa, so bonding strength can be 129 MPa, so bonding strength can bemeasured without any problem with this measured without any problem with thistest piece shape
test piece shape

Stress analysis results for the 14th stage©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.127(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ① Verification of adhesive strength assuming cylindrical pipe shape○ Required bonding strength of pipe

① Top ring/pipe bonding section
Maximum pneumatic thrust: 636 N (0.1 MPa)
Bonding area: 4318 mm2

Required breaking strength: 2.4 MPa = (636 N/4318 mm2) × 18 (safety factor)
Top ring
Lower pipe
Upper pipe

Pipe thrust

CollarPiston② Collar/pipe bonding section
Bonding area is larger than top ring, so lower
load than ①③ Piston/pipe bonding section
Not subjected to loads greater than thesliding resistance©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.128(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ① Verification of adhesive strength assuming cylindrical pipe shape○ Results of bonding strength confirmation test for pipe bonding sections- Fracture strength was about 1/2 to 1/3 of that evaluated using flat plates.
- Although the Φ90 piece showed a larger drop, the bonding strength was 5.9 MPa, which was confirmed to
exceed the required bonding strength of 2.4 MPa.

As such, it was determined that there was sufficient bonding strength required for equipment
operation, even when using a cylindrical shape.
Φ30

Φ90

Plate

Pipe

Plate

Pipe

Breaking stress
[MPa]

24.4

14.0

18.6

5.9

Fracture mode

CFRP material
fracture

CFRP material
fracture

CFRP material
fracture

CFRP material
fractureType 2Type 2Type 1
Type 1

Bonding area

Fractureinterface
A layer of
CFRP remains
on the AL
surface

CFRP residue

A layer of
CFRP remains
on the AL
surface

CFRP residue©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.129(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ② Verification of fabricability of aluminum pipes, an alternative design for thetelescopic pipe
Report for FY2021
Consideration of adopting aluminum as an alternative pipe material
Main target specifications

CFRP (inner and outer UD
surface)

Aluminum (A7075)

Manufacturable

Pipe outer diameterΦ100 (1st stage) to Φ35 (14thstage)

Manufacturable

Pipe length

431.5 mm (1st stage) to 658.2
mm (14th stage)

Manufacturable

14

Manufacturable

Number of pipe stages
Pipe wall thickness

1 mm or lessOuter diameter tolerance+0.2/0ｍｍ

Inner diameter tolerance

H9
1st stage: Φ95 +0.087 to 0
13th stage: Φ35 +0.062 to 0

Fabricability

Straightness

0.1 mm or lessRoundness

0.2 mm or less

Inner surface roughness

Manufacturable

Ra 3.2 or less1.6 (actual result)0.3 (actual result)

Tensile strength (axial
direction)

100 MPa or more

Pipe stages 2 to 9: 796
Pipe stages 10 to 14: 618

570

Tensile strength(circumferential direction)

100 MPa or more

Pipe stages 2 to 9: 603
Pipe stages 10 to 14: 129570

CFRP: High-strength pre-preg cannot be used for stages 10 to 14
because of the small pipe diameter, so circumferential tensile strength
is low

Safety factor (0.3 MPapressure resistance)

15 or higher

Pipe stages 2 to 9: 45
Pipe stages 10 to 14: 20

38

CFRP: High-strength pre-preg cannot be used for stages 10 to 14
because of the small pipe diameter, so the safety factor is low, but not
low enough to be a problem

10 mm or less
Looseness between stages
not included

2.0

3.4

Structural analysis assuming zero looseness (bonding condition) for
each stage of the telescopic pipe

9 kg or less

8.0

9.4

Investigation equipment not included
Includes scrapers, pistons, stopper rings, etc. in addition to pipes

Deflection
14-stage weight

Robustness

Since manufacturing issues were expected with the CFRP pipe, test
manufacturing using aluminum for the 3 stages at the tip was
conducted as an alternative

Manufacturable
Aluminum is difficult to manufacture with 1 mm wall thickness, andDifficult to guarantee shape only one company accepted the order under the target precision
Manufacturable
conditions (test machining), so the evaluation was performed on a test
tolerance
manufacture of a thin pipe (12th, 13th, and 14th stages: inner
Manufacturable
Manufacturable
diameter Φ40 to Φ30), which would difficult to make rigid using CFRP.
Difficult to guarantee precisionThis resulted in approx. 0.3 mm warping in the 13th stage, which
After manufacturing at +0.4/0
prevented full retraction into the 12th stage.
mm, match up the components
Manufacturable
that join together (pistons, etc.)
The aluminum telescopic pipe (1F2_investigation inside the PCV (A2))
in order to adjust dimensions
manufactured previously has a wall thickness of 2.5 mm. With thisthickness, if the maximum outer diameter is less than Φ100, only a 7Difficult to machine
Manufacturable
13th stage actual result: 0.3 stage pipe can be formed and it will not be able to achieve therequired length when extended (access to the furnace bottom will notmm
be possible)
Manufacturable
Manufacturable

Strength

WeightRemarks

Cumulative dose resistance
Wear/repeatability

7200 Gy or higher

7200 Gy or higher

7200 Gy or higher

1 or more surveys possible

Evaluation required

Evaluation required

3 days or more at 100 Gy/hUsing aluminum is an issue in terms of fabricability (ease of machining)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.130(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ② Verification of fabricability of aluminum pipes, an alternative design for the
Retraction of the 13th stage fell shorttelescopic pipeby about 140 mm.
○ Background- In FY2021, a test manufacturing of the top three stages (stages 12 to14) showed warping of about 0.3 mm at the 13th stage. When stages
13th stage pipe
12 to 14 were assembled, retraction of the 13th stage fell short by
Full
about 140 mm.
retraction- Since there was no warpage in the machining process, it was inferredthat the hard anodizing process performed after machining was the
problem.
○ Countermeasures
Change hard anodizing method to improve stability.

14th stage pipe

13th stage pipe

Warping occurs
in the 13th stage

Full
extension

12th stage pipe

Inner diametertarget (mm)

Inner diameter
result (mm)Outer
diametertarget (mm)Outer diameter
result (mm)Straightness
target (mm)Straightness
result (mm)12th stagepipe

Φ40 +0.062/0

PassΦ40.05

Φ42±0.1

Pass Φ41.98

0.1 or less

Pass

0.1 orless

13th stagepipe

Φ35 +0.062/0

PassΦ35.03

Φ37±0.1

Pass Φ37.02

0.1 or less

FailAround0.3

14th stagepipe

Φ30 +0.052/0

PassΦ30.03

Φ32 ±0.1

Pass Φ32.04

0.1 or less

Pass

0.1 orless©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.131(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ② Verification of fabricability of aluminum pipes, an alternative design for the①②
telescopic pipe

Inner diametertarget (mm)Y

Internal diameter
error (mm)○ Countermeasures- For this reason, the 2nd and 3rd steps were prioritized for test
manufacturing.
- The same processing method used for the small diameter pipe
resulted in a 0.02 mm expansion of the pipe ends and a variationin the difference in inner diameter between the two ends and thecenter of the pipe. To eliminate residual stress in the aluminummaterial, machining was performed after the annealing
process, which allowed the inner diameter error between the twoends and the center to be kept constant.
- After this, hard anodizing is performed.
Machining results after annealing treatment
Before hard anodizing (anodizing thickness: 15 μm assumed)

X

No annealing

Internal diameter
error (mm)○ Background- For the small-diameter stages 12 to 14, countermeasures involving
changing the hard anodizing method appear promising.
- However, the 2nd and 3rd stages are thin-walled and large indiameter, making machining difficult.

③With annealing

TargetTargetInner diameter
result (mm)Outer
diametertarget (mm)Outer diameter
result (mm)Straightness
target (mm)Straightness
result (mm)

2nd stagepipe

Φ90+0.12/-0.03

PassΦ90.12

Φ92±0.1

Pass Φ91.95

0.1 or less

Pass

0.1 orless

3rd stagepipe

Φ85+0.12/-0.03

PassΦ85.07

Φ87±0.1

Pass Φ86.95

0.1 or less

Pass

0.1 orless©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.132(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ② Verification of fabricability of aluminum pipes, an alternative design for thetelescopic pipe
○ Confirmation of aluminum pipe assembly- Operation was checked manually by assembling the manufactured aluminum pipes and it was verified that theyextend and retract without any snagging.

It was determined that manufacture is also possible using aluminum pipes.

2nd and 3rd stages (retracted state)

12th to 14th stages (retracted state)

2nd and 3rd stages (extended state)

12th to 14th stages (extended state)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.133(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ③ Evaluation of noise caused by investigation equipment to dosimeter○ Purpose- Since the dosimeters used need to transmit minute currents of several pA, they are considered relatively
vulnerable to leakage currents generated at mechanical contact points such as connectors and slip rings, andnoise due to crosstalk from motor cables included in the composite cable. For this reason, tests to confirm theeffects of noise will be conducted and noise reduction methods will be studied.
- In FY2022, the noise when combined with the investigation equipment will be evaluated. (Noise from slip rings
during motor operation evaluated in FY2021)○ Test plan
- Connect the dosimeter elements to be used via composite cables and connectors equivalent to those used in
the actual equipment.
- Check the effect of noise on the dosimeter with the motor and camera connected to the composite cable.
: Dosimeter cable connector

Control panel section
Cable winder

Dosimeter

Investigation
Telescopic pipe equipment section

controller

Composite cable

Dosimeter

Servo

Slip ring

controller

Cameracontroller

Drum
motor

Composite
cable

Servo
CameraMotor
controller

Note: Connectors for components other than the dosimeter are omitted©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.134(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ③ Evaluation of noise caused by investigation equipment to dosimeter○ Test results① Effect of leakage current
Leakage current value when the cable (including slip rings, etc.) is connected from the dosimeter controller to the investigation equipment
section•The current value acquired at the controller side was evaluated with a simulated measurement signal (10 nA; equivalent to 20 [Gy/h])
output from the dosimeter➢ Loss due to leakage current was confirmed to be 0.44 nA (equivalent to 0.9 Gy/h)➢ Although an error of about 5% was observed, it was confirmed that the leakage current values did not vary significantly overtime
It was determined that measures could be taken by preparing a calibration table in advance and anticipating the amount of loss
② Effects of noise
Impact from components with signal lines placed on the cable assembly where the dosimeter cable is located was evaluated•Drives cable drum motors, servo motors, and investigation equipment camera during data acquisition under conditions where thedosimeter does not output a measurement signal➢ Noise of 35.7 nA (equivalent to 7.1 Gy/h) at peak value when driving cable drum motors and servo motors➢ Due to spike noise, measurement is not affected after motor operation is stopped
It was determined that going forward, it will be possible to reduce the impact using a smoothing process, etc.
Noise level (peak value)
MovingNo smoothing
average*

0.20

0.05

0.20

0.05

0.65

0.05

0.65

0.15

Drum motor operation

4.09

0.66

7.77

1.69

Servo motor operation

5.71

0.89

35.66

3.15

Camera operation

0.44

0.10

0.44

0.44

Unit: nA

Control panel main
power OFF
Control panel main
power ON

Current value [nA]

Electromagnetic noise level during component operation

Amount of noise (standard
deviation)
MovingNo smoothing average*

Spike noiseTime [s]Control panel main
power OFF
Servo motor operation

Control panel main
power ON
Camera operation

Drum motor operation*Moving average time is 5 seconds©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.135(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ④ Impact assessment of cumulative dose on video image due to CMOS camera irradiation○ Background- Radiation resistance evaluation conducted in FY2021 confirmed that video images could be output even after
irradiation of 1600 Gy.
However, it was confirmed that after irradiation, the video image was disturbed in low light intensity.
Depending on the filming conditions, such as viewing a distant target, this phenomenon may occur, and there is apossibility that the target will not be seen.

Lighting conditions: Laboratory lighting (36 lx)

Before irradiation

Lighting conditions: Laboratory lighting (36 lx)

Lighting conditions: Camera lighting (570 lx)

After irradiation (total cumulative dose of 1600 Gy or more)○ Purpose- Identify the accumulated dose at which the video image is disturbed.
- The accumulated dose (survey time) at which the image is disturbed will be reflected in the survey plan.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.136(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ④ Impact assessment of cumulative dose on video image due to CMOS camera irradiation○ Test outline- Irradiation is performed at a constant dose rate, and the irradiation is stopped at regular intervals to check theimages by changing the lighting intensity, object distance*, and other filming conditions, and the accumulated
dose when the images are disturbed is recorded.
*The gain (brightness amplification rate) is changed by changing the area of the object in the image.

Irradiation

No irradiation
Image
confirmation--- Conducted repeatedly

20 min.
60 min.
Proposed test schedule

Monitoringroom
Monitor + recording
components

IrradiationchambercameraDistance tosource(Dose rate)
Source*Filming distance

Test chart ortest piece

Dose rate meter

CameraLighting
controller*Camera Control Unit

Lighting

Proposed system for radiation
resistance testingExternal
lighting

Conceptual image of test system©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.137(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ④ Impact assessment of cumulative dose on video image due to CMOS camera irradiation○ Test result: New CMOS camera
Total dose at which image disturbance (color change) was observed: 1440 Gy
Cumulative dose at which the image stopped: 1584 Gy

Image
Cumulative 1152 Cumulative 1440
Before irradiation
Gy after 4th
Gy after 5th
irradiation
irradiation

Cumulative 1584
Cumulative 1728
Gy partway
Gy after 6th
through 6th
irradiation
irradiation

External
lighting
Approx. 650 lx

External
lighting
Approx. 20 lx

Change in contrast
Increased noise(Identified from 576
Gy)

Color change in addition to
an intensification in thechange noted after the 4th
irradiation

The image stopped during the 6th
irradiation, so the irradiation was stopped
and the image was checked
After that, the image was not stable(repeatedly restored and stopped)
Note: LEDs are normal, no abnormal heat generation in camera©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.138(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ④ Impact assessment of cumulative dose on video image due to CMOS camera irradiation○ Test results: CMOS camera irradiated to 1600 Gy (used in the test conducted in the previous fiscal year)
Cumulative dose at which the image stopped: 2060 Gy
Image stopped during 2nd irradiation (after 1 h 40 m)
After that it reappeared and stopped several times, but
eventually the output remained frozen

Before irradiation
Cumulative dose: 1600
Gy

After 1st irradiation
Cumulative dose:
1888 Gy

After 2nd irradiation
Cumulative dose:
2176 Gy

External lighting
Approx. 650 lx

External lighting
Approx. 20 lx*Image cut-off status
After 2nd irradiation (cumulative 2176 Gy): Image stopped*Turning the power on
After 3rd irradiation (cumulative 2464 Gy): Image not restored even after turning the power back on.
and off tried.
After 5th irradiation (cumulative 3040 Gy): Image restored after turning the power back on. However, stopped after
about 10 seconds.
7th irradiation (cumulative 3616 Gy): Image not restored even after turning the power back on.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.139(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ④ Impact assessment of cumulative dose on video image due to CMOS camera irradiation○ SummaryThe cumulative dose at which the video stopped was 1584 Gy for the new product and 2060 Gy for theold product, showing differences depending on the individual unit.
Disturbances (color changes) in the image were confirmed at around a cumulative dose of 1440 Gy.

Image disturbance(color changes)

Image stopped

Unirradiated camera

1440 Gy

1584 Gy

Camera irradiated with
1600 Gy in the previous
fiscal year

(Confirmed after
completing the test in
previous fiscal year)

2060 Gy©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.140(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture○ Background• In FY2021, a simulator was used to simultaneously acquire two simulated video images (object display andoverhead view from a fixed point) from a camera mounted on the arm-type access equipment for retrieval (fixedpoint camera) and a camera mounted on the investigation equipment (moving camera).
• In FY2022, a simulator will be used to check the field of view of the fixed-point camera and investigation equipment
camera when the telescopic pipe is retracted/extended and when it is tilted, and to study the operation method of
the entire system.
Moving camera
Perspective 4

Perspective 3

Telescopic pipe +moving camera

Fixed point
cameraPerspective
2

Fixed point camera
image

Moving camera image

Perspective
1

3D model of the structure used
©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.141(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture○ Study policies• Examine the operational procedures of the equipment in using the telescopic access equipment to accessthe anticipated hole location.
• The simulator is used to acquire simulated video images that anticipated to be obtained by the arm fixedpoint camera/investigation equipment camera when positioning relative to the hole. In addition, a simulated
video image obtained in the case of misalignment is acquired.
• The equipment operation procedures are reviewed based on the simulated video images obtained.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3 No.142

6. Implementation details(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ West← NorthEstimated hole position

South →↓ EastUnit 2: Camera image with telescopic pipe retracted©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.143(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ WestLower insulation← NorthEstimated hole position

South →↓ EastUnit 2: Camera image with telescopic pipe extended 2000 mm from retracted state©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.144(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ West← NorthEstimated hole position

South →↓ EastUnit 2: Camera image with telescopic pipe extended 3500 mm from retracted state⇒ The fixed point camera on the arm can only check approximate behavior of the telescopic pipe
⇒ The presence of the investigation equipment at the center position of the opening is determined by whether thecenter of the opening is at the center position of the camera image.
⇒ The capability to determine the dimensions of the opening is necessary because the dimensions of the opening on
the actual unit are unknown.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.145(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ West← NorthEstimated hole position

South →↓ EastUnit 2: Camera image with telescopic pipe retracted (tilted 2° to the west)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.146(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ West← NorthEstimated hole position

South →↓ EastUnit 2: Camera image with telescopic pipe extended 1000 mm from retracted state (tilted 2° to the west)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.147(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ WestLower insulation← North Estimated hole position

South →↓ EastUnit 2: Camera image with telescopic pipe extended 2000 mm from retracted state (tilted 2° to the west)©International Research Institute for Nuclear Decommissioning

Units 2 and 3 No.148

6. Implementation details(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture
Moving camera

Fixed point camera↑ West← NorthEstimated holeposition

South →↓ EastUnit 2: Camera image with telescopic pipe extended 3000 mm from retracted state (tilted 2° to the west)©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.149(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑤ Evaluation of recognition by arm fixed-point camera of telescopic pipe passage clearance and extension amount⑥ Evaluation of investigation equipment camera’s ability to determine whether an opening can be passed through,and whether it can determine the direction of correction of telescopic pipe posture

Moving camera

Fixed point camera

If the telescopic pipe is verticalMoving camera

Fixed point camera

If the telescopic pipe is tilted 2°.

⇒ Except in the case of a large tilt, it is difficult to determine the tilt from the image alone.
⇒ A function is required to determine the inclination of the telescopic pipe itself.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.150(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)○ Background- In the FY2021 test, it was confirmed that the 14-stage telescopic pipe tends to tilt in the direction of the anti-rotation
rails located to the sides during extension, that if looseness between the pipe sections is unbalanced in one
direction, the tip deviation of the telescopic pipe is +144.7 to -218.3 mm (the direction where the anti-rotation rail ofthe telescopic pipe is fixed is negative), and that during emergency retraction, when the pipe internal pressure is
reduced from the fully extended state, the telescopic pipe gradually tilts, and the 14th stage at the tip titles at least
5.5 degrees.
218.3 mm 144.7 mm−+

Vertical position

Full extension

Amount of tip deviation caused bytilting due to looseness©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.151(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension○ Purpose
The feasibility evaluation test of the 14-stage telescopic pipe in FY2021 confirmed that thetelescopic pipe tends to tilt in the direction of the anti-rotation rails. During the test, thetelescopic pipe was found to be mounted with a 0.1° tilt in the direction of the rails. However,when converted to the amount of deviation at the end of the telescopic pipe when fully
extended, the tilt was about 10 mm, so it was determined that the tilt would have no effect on
the extension behavior, and the test was conducted with the telescopic pipe mounted in thiscondition.
It is estimated that the factors that cause the telescopic pipe to tilt toward the anti-rotation
rails include the mounting angle of the telescopic pipe and the presence or absence of the antirotation rails. Therefore, in order to examine measures to deter tilting, verification was first
performed on the FY2021 equipment and test system regarding the reproducibility of the tilting
behavior identified in the previous year, as well as its dependence on the layout of the rotation
control rails and the mounting angle of the telescopic pipe.
○ Test planNo.

Test nameGoal

1

Verify reproducibility of the Checking to see if tilting toward the antirotation rails is reproduced.
FY2021 test

2

Verification of tilt direction
when telescopic pipe isslightly inclined

3

Verification of tilt
suppression effect when
the layout of the antirotation rails is changed

14-stage telescopic pipe, fully
extended

Test conditions- Anti-rotation rails direction:① Same orientation as during the FY2021 test
② 180° from the orientation of ①
- Mounting angle: vertical- Anti-rotation rails direction:
Check to see if slight inclination is a factor inSame orientation as the FY2021 test
determining the direction of tilt in one- Mounting angle: 0.1° inclination on the opposite side of the antidirection.
rotation rails
Evaluate whether the tilt of the telescopic
pipe can be suppressed by evenly arranging- Anti-rotation rails direction: Laid out in a spiral pattern at 90°
the anti-rotation rails, which were previously
increments
laid out in a single direction, and confirm the- Mounting angle: verticalarrangement pattern that can best suppress
the tilt.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3 No.152

6. Implementation details(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension

Plumb line

Plumb line fory-direction
measurement

Plumb line forx-direction
measurement

Investigation
Black circle: Telescopic pipe
equipment
Gray: Cable winder
mockup: Positions plumb lines hungzy1900 mm

Full diagram of the test system

Measurement
position at 7thstage
extensiony1900 mm

1900 mm

1900 mm 1400 mm○ Test system- As in the FY2021 test, scaffolding was set up around the telescopic pipe and the telescopic pipe was made to extend and retract. The
telescopic pipe’s direction of tilt and the amount of tip deviation were determined by measuring the distance between the pipe andplumb lines (strings) placed at two locations in the +x and -y directions relative to the pipe.
- The telescopic pipe was mounted so that the 1st stage pipe was vertical (tilt measured at 90.0° in the x and y directions).
- The amount of tip deviation was measured three times when the telescopic pipe was extended up to the 7th stage pipe, where thedirection of inclination of the telescopic pipe could be determined, and once when the pipe was extended all the way to the 14th stage.

Measurement
position at full
extensionx
14th stage pipe

(hidden until the
14th stage is
extended)

Cable winder
viewing window

Definition of orientations (top-down view of test apparatus)

Deviation measurement position©International Research Institute for Nuclear Decommissioning

Units 2 and
3

6. Implementation details

No.153(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension○ Test No.1: Verify reproducibility of the FY2021 test
To confirm that the telescopic pipe always leans toward the anti-rotation rails as it is extended, as in the FY2021 test, the telescopic
pipe was mounted vertically with high accuracy and tested under two conditions, one with the rails positioned in the -x direction and theother in the +x direction, as in FY2021.

Anti-rotation
rails direction-x direction(Same orientation as
the FY2021 test)+x direction(opposite direction
from the FY2021
test)

Measurement(date
performed)

Amount of tip
deviation [mm]Tilt
direction

7th stage pipe
extension

Full extension of
14 stages

δx

δy

δx

δy

1st (Sep. 21, 2022)

-17

24

－

－

-x, +y2nd (Oct. 21, 2022)

-2

-11

－

－

-y

3rd (Oct. 28, 2022)

-3

-17

-1

-128

-y

1st (Nov. 8, 2022)

45

21

126

124

+x, +y2nd (Nov. 11, 2022)

40

34

－

－

+x, +y3rd (Nov. 11, 2022)

46

39

－

－

+x, +y4th (Nov. 11, 2022)

42

40

－

－

+x, +yAnti-rotation
rails directionyyNov. 11 results
Measure theamount ofdeviation ateach stage

Anti-rotation
rails directionxRails: -x direction(Same direction as FY2021)

x
Rails: +x direction(Opposite direction from FY2021)

Amount of tip deviation at 7th stage extension
Test results- Along with pipe extension, there was a tendency for it to tilt in the x-direction toward the anti-rotation rails, and it never tilted in the
opposite direction to the rails. However, there was both plus and minus tilt in the y-direction, and the direction of tilting when thepipe was extended was indeterminate and did not reproduce the direction of tilting in the FY2021 test.
- Even under the same conditions, the direction of tilt and the amount of tip deviation varied depending on the test date, but as shownby the Nov. 11 results, with the rails positioned in the +x direction, the results were reproduced within the same test date.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.154(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension○ Test No.2: Verification of tilt direction when telescopic pipe is slightly inclined
The results of test No.1 showed that the direction of inclination of the FY2021 test was not reproduced and was indeterminate.
It is possible that the pipe had a tendency to tilt toward the rail because the 1st stage pipe was inclined 0.1° toward the rail in the
FY2021 test.
Since in test No.1, the pipe never tilted to the side opposite the rails, in test No.2 the direction of tilt was evaluated by inclining the pipe
0.1° in the direction opposite the rails.

Amount of tip deviation [mm]Rotationcontrol rails
direction-x direction(orientation in
the FY2021
test)

Measurement (dateperformed)

7th stage pipe
extension

Full extension of
14 stages

Tilt
direction

δx

δy

δx

δy

1st (Dec. 2, 2022)

18

-19

－

－

+x, -y2nd (Dec. 5, 2022)

18

-17

－

－

+x, -y3rd (Dec. 5, 2022)

17

-20

－

－

+x, -yIn all three measurements, a tendency totilt in the +x direction, to which the pipe
was inclined by 0.1° relative to the -x
direction in which the rails were located,
was identified.

Test results- When the telescopic pipe was mounted vertically with high precision, the pipe did not tilt in the opposite direction of the anti-rotation
rails, but when it was mounted inclined 0.1° to the opposite direction of the rails, it tilted in that direction when extended. This indicatesthat the direction of tilt of the telescopic pipe when extended is affected by the accuracy of the mounting posture. The reason that thepipe tilted only in the direction of the rails in the FY2021 test may also be due to the inclination at the time of mounting.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.155(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension○ Test No.3: Verification of tilt suppression effect when the layout direction of the anti-rotation rails is changed- The results of test No.1 show that as it is extended, the telescopic pipe tilts not only in the x-direction but also in the y-direction. The
evaluation was performed by placing the anti-rotation rails in a spiral arrangement with the orientation of the rails changing by 90° at
each stage, with the objective of suppressing tilting in both the x and y directions.
Amount of tip deviation [mm]Full extension of 14
stagesδxδyMeasurement

Laid out in a spiral pattern at 90°
increments

1st

45

16

185

124

+x, +y-x direction (result of test No.1)

3rd

-3

-17

-1

-128

-y

+x direction (result of test No.1)

1st

45

21

126

124

+x, +yTilt direction

y-direction

x-direction

1st

Extension height [mm]Amount of tip
deviation

Extension height [mm]Direction of anti-rotation
rail for 2nd stage pipe

7th stage pipe
extension
δxδyAnti-rotation rails direction

1st

Amount of tip deviation at each stage [mm]Amount of tip deviation at each stage [mm]Test results- Since the amount of tip deviation when the pipe was extended to the 14th stage was larger than when the rails were in one direction,changing the layout of the anti-rotation rails had no effect in suppressing tilt. This may be due to the significant effect of the tilt of thepipe on the base side.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.156(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension○ Summary of the tests to verify the factors behind tilting of the telescopic pipe
- When the telescopic pipe was mounted vertically with high accuracy, it reproduced the same tendency to tilt toward
the anti-rotation rails when extended as in the FY2021 test, but it also tilted perpendicular to the rails and its
direction was indeterminate. Moreover, although the direction of tilt and amount of tip deviation were reproducible
under the same conditions and on the same test date, they changed when the test date changed.
It was determined that the direction of tilt is variable and difficult to predict prior to extension.
- When the telescopic pipe was mounted at a slight incline, 0.1° to the vertical, it tilted in that direction duringextension.
It was determined that the direction of telescopic pipe extension is affected by the direction of inclination
before extension, however small.
In addition, the phenomenon observed in the FY2021 test, in which the telescopic pipe tilted toward theanti-rotation rails as it was extended, was determined to be due to the inclination at the time of mounting.
- When the orientation of the anti-rotation rails was changed for each stage of the pipe, the telescopic pipe showed
greater tip deviation than when the rails were oriented in one direction.

Changing the orientation of the anti-rotation rails was determined to have no effect.
In this fiscal year’s test, as in the previous fiscal year, the rotation restraining rails were laid out in
one direction.

©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.157(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)○ Purpose- The factors that cause tilting and rattling during telescopic pipe extension are considered to be the pipe-to-pipe fit and the gaps
between the pipes.
This year, the following measures were considered to prevent tilting of the telescopic pipe.
① Change of taper angle of collar/stopper ring (for easier fitting)② Larger collar diameter (to narrow the gap between pipes)③ Change to a harder dust seal (to prevent wobble)- An evaluation was conducted to determine whether these measures produced an improvement and the effect on theextension/retraction motion of the telescopic pipe.
Investigationequipment

Dust seal
CFRP pipe (upper)

Taper angle of collar andstopper ring fitting part
Telescopic pipe

Stopper ring
Top ring(Fixed to the lower pipe)
Scraper

CollarAnti-rotation rail

CablewinderPiston

CFRP pipe (lower)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.158(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)① Change in taper angle of collar/stopper ring / ② Larger collar diameter- In FY2021, the taper angle of the collar was 45°, but it is anticipated that a more acute angle will make it easier for the fitting
parts to fit and increase rigidity. On the other hand, since jamming may occur, making it difficult for the telescopic pipe to pull out
during retraction, three taper angles of 15°, 30°, and 45° were selected for comparison and evaluation in the test.
- When the gap between the collar and pipe is reduced (0.2 to 0.4 mm ⇒ 0.1 to 0.2 mm), sliding resistance may increase fromFY2021. Also, consideration is being given to increasing the hardness of the sliding part material, but it is possible that the sliding
resistance will also differ.
⇒ It was decided to evaluate by testing whether the sliding resistance increases to the extent that it affects theextension/retraction motion of the telescopic pipe, and whether the sliding resistance differs depending on the taper angle.

Items

FY2021

Proposedcountermeasures for
FY2022

Collar taper angle

45°

Select from 15°, 30°, 45

Gap between collar andpipe

0.2 to 0.4 mm

0.1 to 0.2 mm

0.1 mm thick ultraHardening of collar sliding
high molecularpart material
weightpolyethylene tape0.03 mm thickfluoroplastic coating

Stopper ring

CollarCollar taper angle 15° Collar taper angle 30°

Collar taper angle 45°©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.159(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)① Change in taper angle of collar/stopper ring / ② Larger collar diameter○ Test plan and test object- If the collar taper angle is made acute, it will fit more easily into the stopper ring, which may have the effect of suppressing thetelescopic pipe tilt, but it may also be more difficult to pull out during retraction due to jamming, etc. Therefore, the taper angle isselected by measuring the tilt suppression effect and the force required to remove the fitting parts (Test No.1/No.2)- Increasing the diameter of the collar may increase sliding resistance, so sliding resistance will be measured to see if it affects
telescopic pipe extension (Test No.1)

Test item

Goal

Test outline

Test conditions

Test No.1
Measurement of sliding
resistance when collar
diameter and sliding partmaterial are changed

Check the effect on sliding
resistance by increasing thecollar diameter to narrow the gap
between the collar and pipe andby changing the sliding partmaterial.

A piston with a collar is placed in a pipethat simulates the 1st stage pipe. Sliding
resistance is measured by pulling a wireattached to the piston with a load cell.

- Collar taper angle:
15°, 30°, 45°

Test No.2
Comparison of force
required to remove thecollar for different taper
anglesIdentify and evaluate the force
required to remove at each taper
angle, as an acute collar taper
angle may make it fit more easily
into the stopper ring andincrease the force when thetelescopic pipe retracts.

A piston with a collar is used in a pipe
simulating the 1st stage pipe, andpneumatic pressure is applied to makethe collar of the piston fit into the stopperring of the 1st stage pipe. The pressure isthen released and a load cell is used toapply a vertical load and measure theforce required to remove.

- Collar taper angle:
15°, 30°, 45°- Pressure supplied: 0.1 MPa,
0.2 MPa

Test No.3
Verification of tilt
suppression effect ofdifferent collar taper
anglesWhen the collar taper angle ismade acute, it will fit more easily
into the stopper ring, which is
expected to have a tilt
suppression effect. Evaluate theeffect of collar taper angle on tilt
suppression

Using pipes simulating the thickness ofthe 1st and 2nd stages, pneumaticpressure is applied to make the collar of
the 2nd stage pipe fit into the stopper ringof the 1st stage pipe. A horizontal load isapplied to the end of the 2nd stage pipe
until the looseness is collapsed, and thedisplacement of the end of the 2nd stage
pipe is measured.

- Collar taper angle:
15°, 30°, 45°- Pressure supplied: 0.03
MPa, 0.1 MPa- Horizontal load: Until any
looseness is collapsed

Note: Regarding the pressure supplied for the test, 0.03 MPa is the pressure supplied when extending the 2ndstage of the telescopic pipe, and 0.10 MPa is the maximum pressure supplied to the telescopic pipe until
last year. This year, in order to suppress tilting, consideration was given to increasing the pressure
supplied to the telescopic pipe, with 0.20 MPa being the maximum value.

Mockup 2ndstage pipe

Scraper(Stopper ringplaced on theinside)Mockup 1ststage pipe
Piston(3 types, with taper
angles of 15°, 30°, and45°, test-manufactured)

Test piece©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.160(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)○ Test No.1: Measurement of sliding resistance when collar diameter and sliding part material are changed
Test purpose
Check the effect on sliding resistance by increasing the collar diameter and narrowing the gap between the collar and pipe and bychanging the sliding part material.
Test outline
The 2nd stage piston is placed in the 1st stage pipe, and the sliding resistance of the moving piston is measured by a load cell tocompare the effect of the collar taper angle.

Measurement results

Mockup 1st stage pipe

Collar taper angle

PistonSliding resistanceLoad cell

Test system

15°

30°

45°

Approx. 10 N

Test results- The sliding resistance was about 10 N at any taper angle.
⇒ Verified that collar taper angle makes no significant difference.
⇒ Because a thrust force of approximately 130 N is generated in
the 2nd stage pipe during telescopic pipe extension, and therated tensile force of the cable winder used during telescopic
pipe retraction is 170 N, the sliding resistance is sufficiently
small compared to the force during extension/retraction, so it isdetermined that there will not be any problems with operation of
the telescopic pipe.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.161(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)○ Test No.2: Comparative test of force required to remove the collar for different taper angles
Test purpose
A sharp collar taper angle may increase the tensile force required to retract the telescopic pipe because of the increased likelihoodof jamming in the stopper ring. Evaluate the force required to remove the collar and stopper ring at each taper angle.
Test outline
Tests were conducted using a short mockup of a 1st stage pipe and a mockup of a piston with a collar attached. The piston isplaced in a position such that the collar fits into the stopper ring, the pipe is opened to the atmosphere after a predeterminedpressure (0.1 MPa/0.2 MPa) is applied, and a load cell is used to push the piston from above measure the force when it begins todescend.
Load direction from load cell
Measurements of force* required to remove(average of 5 measurements each)
Piston mockup
Taper angle
Pressure
supplied
15°
30°
45°
Scraper(including stopper ringinside)Mockup 1ststage pipe

0.1 MPa

27 N

30 N

28 N

0.2 MPa

47 N

27 N

27 N

*Value obtained by adding the weight of the piston to the load cell reading

Pressure
supplied- Test results
At 30° and 45°, there was no significant difference in the force required tolower the piston when the pressure supplied was increased, indicating that therequired tensile force was unaffected.
On the other hand, at 15°, the measured values also increased when the
supply pressure was increased to 0.2 MPa, indicating that increasing thepressure affects the required tensile force.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.162(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)○ Test No.3: Verification of tilt suppression effect of different collar taper angles
Test purpose
It is possible that if the collar taper angle is made acute, the collar will fit into the stopper ring more easily, which can be expected tosuppress tilting.
Perform a comparative evaluation of the extent to which tilt can be suppressed by the collar taper angle
Test outline
The looseness width is evaluated by applying a pressure of 0.03 MPa/0.10 MPa to a short mockup of the 1st and 2nd stage pipes,
applying a horizontal load to the tip of the 2nd stage pipe in the + and - directions, and measuring the displacement of the tip with alaser displacement meter. The horizontal load required to collapse the looseness is measured using the tip of the 2nd stage pipe as
the load point.
Comparison of looseness width(sum of looseness in + direction and - direction)
Load cell
Load direction－
Pressure
15°
30°
45°
Laser displacement meter+
supplied(for measuring horizontal
displacement of pipe
(upper side) tip)

Mockup 2nd stage pipe

0.03 MPa(Pressure used
for telescopic
extension)

5.7 mm 3.2 mm 2.1 mm

0.10 MPa

4.3 mm 3.2 mm 1.7 mm

Scraper
Laser displacement
meter(for measuring horizontal
displacement of scraper)
Mockup 1st stage pipe

Test system- Test results
In terms of looseness, the relationship between the large and smallvalues did not change when the pressure supplied was changed, and thevalues were 45° < 30° < 15°.
The horizontal load required to collapse the looseness was also thelargest at the 45° taper angle, as was rigidity. As such, the trend was
the same despite the change in pressure.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.163(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)
Summary of test results: ① Change in taper angle of collar/stopper ring / ② Larger collar diameter•To select the angle of the collar taper (15°/30°/45°) and to verify the effect of a larger collar diameter, the taper angle was changed
and its effect on the sliding resistance, the force required to remove the pipe, and the tilt suppression effect was verified.

•

When the collar diameter was enlarged, the sliding resistance was about 10 N with no significant difference when the taper angle waschanged. As such, it was confirmed that to be sufficiently small compared to the force during telescopic pipe extension and retraction(during extension: the thrust generated during 2nd stage pipe extension, approx. 130 N; during retraction: the rated tensile force of thecable winder during telescopic pipe retraction, approx. 170 N).
It was determined that there are no problems with telescopic pipe operation with a larger collar diameter.

•

The force required to remove the pipe was not significantly different between the 30° and 45° taper angles, with the force required forthe 15° angle being greater.
•
Regarding the tilt suppression effect, the taper angle of 45° was confirmed to have the smallest range of looseness and the greatest
rigidity.
The taper angle of the collar used for the telescopic pipe was set to 45°, the same as last year.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.164(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)③ Change to a harder dust seal
○ Background•
Each pipe is designed with a dust seal to prevent matter adhered to the pipe surface from entering the equipment during telescopic
pipe retraction (see figure below).
•
Extension/retraction motion while foreign matter (soil, alumina) was adhered to the device was verified in FY2021. The results
showed no significant difference in the internal pressure during telescopic extension or the cable tensile force during retraction evenwhen powdery foreign matter was adhered to the pipe, and as such, it was determined that there was no problem withextension/retraction motion even with foreign matter adhered to the pipe.
•
On the other hand, the dust seal used was soft and there were concerns about its durability (susceptibility to wear and tear).
Therefore, a survey of similar materials was conducted, and a relatively hard material was selected as an alternative candidate.
•
The following items were evaluated to assess the impact of changing the dust seal.
(a) Effect on foreign matter removal performance(b) Effect on telescopic pipe extension/retraction motion(c) Effect on tilting behavior

Dust seal
Investigationequipment
CFRP pipe (upper side)

Stopper ring (not fixed)
Top ring (fixed to the lower pipe)

CollarScraper
Telescopic pipe

Anti-rotation rail
(Laid out in one direction in FY2021)

Scrapers (one for each stage)
Cable
winderPiston
CFRP pipe (lower side)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.165(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)③ Change to a harder dust seal
○ Test plan
- Comparative tests were conducted on the following three items regarding the effects of changing dust seals.

Test name

Goal

Test conditions

Test No.1
Verification of effect on foreignmaterial removal performance

Powder (soil/alumina) was applied to the surface of the 2ndstage pipe of the 14-stage telescopic pipe test-manufactured
in FY2021, and verification was performed to ascertain
foreign substance removal performance and determine
whether retraction/extension operations were possible.
(Changing the dust seal at the tip of the 1st stage)- Dust seals: FY2022 dust seals (those from FY2021 havealready been evaluated)- Foreign matter: ① soil, ② alumina- Attachment point: 2nd stage of 14-stage telescopic pipe testmanufactured in FY2021

Test No.2
Effect on telescopic pipe
extension/retraction motion

Confirm that extension/retraction motion is possible, since
the changed dust seal may have greater sliding resistance.
Since the pipe driving force is smaller for emergency
retraction (retraction using only depressurization in the pipe)
than for normal extension/retraction motion, the operation
was verified for the 14th stage pipe, where the retraction
force due to the action of its own weight and negative
pressure is especially small. (Changing the dust seal at the
tip of the 13th stage)- Dust seal: FY2022 dust seal

Test No.3
Confirmation of impact on tilt
control effectUsing the short pipe used to select the taper angle, compare
the tip displacement of the FY2022 dust seal with the
FY2021 dust seal when a horizontal load is applied.

- Dust seal: FY2021 dust seal / FY2022 dust seal
- Taper angle: 45°- Pressure supplied: 0.03 MPa (short pipe: pressure at 2nd stage
extension)©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.166(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)③ Change to a harder dust seal
○ Test No.1: Effect on foreign matter removal performance
Test outline•
The dust seal on the first stage of the telescopic pipe was changed and soil (15 μm particle size)/alumina (75 to 100 μm particlesize) was applied to the surface of the 2nd stage pipe to check its performance in removing foreign particles by extending it after
retraction.
Test results•
In the case of soil, the pipe surface after extension was wiped unevenly, but the alumina was wiped off uniformly. Although bothsoil and alumina appeared to have passed through the dust seal, adhesion to the gasket was minimal.
•
Since the FY2021 test results showed uneven wiping of both soil and alumina, the dust seal selected this year was evaluated tohave better performance in removing foreign matter.

(a) Soil(b) Alumina(a) Soil(b) Alumina

Condition of pipe with powder adhered(a) Soil(b) Alumina
Condition of pipe outer surface after
retraction and re-extension

Condition of dust seal after removal offoreign matter©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.167(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)③ Change to a harder dust seal
○ Test No.2: Effect on telescopic pipe extension/retraction motion
Test outline•
The alternative product selected this year is stiffer than that selected in FY2021 and may have greater sliding resistance during
telescopic pipe extension/retraction, so verification will be performed to determine if there is any effect on extension/retraction motion.
•
Since the force to drive the telescopic pipe is smaller for emergency retraction (retraction using only depressurization in the pipe) thanfor normal extension/retraction motion, and the weight of the telescopic pipe itself is smaller on the tip end, the dust seal at the tip of
the 13th stage will be changed and verification performed regarding whether retraction of the 14th stage pipe is possible.
Test results•
After pulling out the 14th pipe about 100 mm by hand, verification was performed to determine whether it could be retracted in caseof emergency (performed once). Although the telescopic pipe did not retract under its own weight, it was confirmed that it did so when
the internal pressure of the pipe was reduced to -22 kPa.
•
In last year’s test of emergency retraction using dust seals, the 14th stage pipe began to retract under its own weight when thetelescopic pipe internal pressure was 9 kPa. In terms of the difference in sliding resistance, the alternative product selected this year
resulted in an increase in sliding resistance of 22 N.
⇒ Although sliding resistance increased, the 14th stage pipe, which is the hardest to retract, was confirmed to do so, and thus it wasdetermined that there would be no problems with telescopic pipe operation.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.168(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)③ Change to a harder dust seal
○ Test No.3: Evaluation of the effect on tilting behavior
Test outline•
Since the dust seal is a component that supports the telescopic pipe, verification is performed to determine if there is any effect on
tilting behavior.
•
The test system is shown below. The displacement was measured with a laser displacement meter when a horizontal load was
temporarily applied to the end of the 2nd stage pipe in the direction of ① and ② and then no load was applied, and a comparison wasmade between the FY2021 dust seal and the current year’s replacement in terms of the difference in looseness width.
Test results•
The results showed that the alternative product used this year was more resilient, and that when no load was applied, the pipe waspushed back vertically and the looseness width was reduced.
Load
directionLaser
displacement
meter

Comparison of looseness width
Dust seal

2nd stagepipe

Pressure supplied

1st stage pipe

0.03 MPa(Pressure used at
2nd stage pipe
extension)

Selected in
FY2021

Selected in
FY2022

2.1 mm

1.8 mm©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.169(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)③ Summary of changing to a harder dust seal
○ Summary of the tests to verify the factors behind tilting of the telescopic pipe•

A comparative evaluation between the dust seal from FY2021 and the alternative product selected this year was conducted.

•

Better results in terms of foreign material removal performance were obtained for this year’s alternative.

•

With respect to the telescopic pipe’s extension/retraction motion, verification was performed to ascertain weather emergency
retraction was possible. The results showed that although sliding resistance increased, the 14th stage pipe, which is the hardest to
retract, was confirmed to do so, and thus it was determined that there would be no problems with telescopic pipe operation.

•

Regarding the suppression of tilting, the current year’s alternative product was found to have a smaller looseness width and force
that acts to push the pipe back in a vertical direction.
The 14-stage telescopic pipe test-manufactured this year will be fitted with the dust seals selected this year, and tests
will be conducted to verify operation.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.170(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details⑦ Control of tilt in the direction of the anti-rotation rails during telescopic pipe extension⑧ Control of looseness due to gaps between stage pipes, and prevention of tilting caused by gaps during
emergency retraction (in emergencies)○ Based on the test results to date, the following improvements were made to the telescopic pipe to be test-manufactured this year.
Test-manufactured
equipment in
FY2021

Test-manufactured
equipment in
FY202245°

45°

0.2 mm

0.1 mmHardening of collar sliding
material

0.1 mm thick ultrahigh molecular weight
polyethylene tape0.03 mm thickfluoroplastic coating

Dust seal

FY2020 alternative
product

FY2022 selected
product

Items evaluated in the test

Collar taper angle

Gap between sliding parts due tolarger collar diameter

Sliding gap
Taper angle

CollarWear ring
Pneumatic gasket

Upper pipe

Lower pipe

©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.171(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ⑨Test manufacturing and evaluation of posture control mechanism○ Background- Due to the possibility that the degree of freedom of the arm for the “Gradually Increasing the Scale ofRetrieval” project may not allow the telescopic pipe to be placed in a vertical position at the anticipated survey
position, a two-axis posture control mechanism is being considered.

Bird’s-eye view

Enlarged view of the posture control mechanism©International Research Institute for Nuclear Decommissioning6. Implementation details

No.172(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ⑨Test manufacturing and evaluation of posture control mechanism○ Equipment design- A review of required specifications and conceptual design was conducted in FY2021. This year, detailed design work
was conducted, and it was confirmed that the specifications for the range of motion and total weight were met.
- Due to the long delivery time for the motor selected for the posture control mechanism, it was not available in time
for the test, so this year it was decided to use a motor that had been incorporated into the test equipment of a past
project. Although the output torque is different, the plan for this test is to measure the torque (motor current value)
during the operation test to confirm that there is no problem with the selected motor.
α-axis operation
Investigation
cameraα-axismechanism

β-axis mechanism(Stroke length)499 mmCable winder
Forward/backward movement mechanism Telescopic pipe

Movement by α-axis mechanism
Design results of the posture control mechanism

Movement by forward/backward movement mechanism

Items

Required
specifications

Designresults

Forward/backward
movementmechanism

499 mm or more

513 mmα-axis mechanism

13° or more

15°

β-axis mechanism

20 mm or more

22 mm

22 kg or less21.0 kg

Ball screw
Horizontal fineadjustment motor
Worm gear

Amount ofmovement

Linear guide

Movement by β-axis mechanism

Total weight©International Research Institute for Nuclear Decommissioning6. Implementation details

No.173(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ⑨Test manufacturing and evaluation of posture control mechanism
The test-manufactured posture control mechanism is shown below.
α-axismechanism

β-axis mechanism

Cable winder+

Telescopic pipe
Investigation equipment
Forward/backward movement mechanism

α-axismechanism: 0°－
Direction of motion of β-axis+ mechanism－

α-axis mechanism

β-axismechanism
Investigation equipment mockup－+
Forward/backward
movement mechanism©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.174(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ⑩ Ensuring uniform drive torque for cable winding drums (reduction of cable tensile force loss)○ Background- In FY2021, in an elemental test of the 14-stage telescopic pipe, it was confirmed that the cable tensile force (motor
drive torque) fluctuated significantly in a short period of time and that the drive load may not be uniform due toimprecise assembly of the gears and drive shaft.
- In FY2022, after implementing measures to address the above issues, elemental tests of the 14-stage telescopic
pipe will be conducted again to evaluate the effectiveness of the countermeasures.
Extension range

Retraction range

Extension range

Retraction range

Extension length (winder)
Telescopic pipe internal pressure
Supplied pressure setting

Supplied pressure [kPa]Tensile force [N]Extension length [mm]Cable tensile force

Rated tensile
force 170 N(actualmeasurement)

Time [s]Time [s]Changes in the extension length, cable tensile force, and internal pressure during telescopic pipe extension/retraction motion©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.175(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details ⑩ Ensuring uniform drive torque for cable winding drums (reduction of cable tensile force loss)
Gear ③’ (gear rotating on a
○ Consideration of countermeasures
shared shaft with gear ③)• The following factors were determined to be responsible for the torqueGear ② Gear ③
Gear ④ (gearfluctuation. After considering each improvement plan, it was decided to checkdirectly connected
the torque of the cable winder alone under no-load conditions.
to drum)① There was a slight interference between the side of the drum and the bolts on Gear ①
the cable winder housing. Therefore, design changes will be made this year to
avoid interference.
② Because of the use of multiple gears, in FY2021, in order to prevent a decrease Gear ②’ (gearin responsiveness due to gear backlash, the distance between gears wasrotating on adesigned to be narrower than the standard value. Improvements will be made shared shaft with
Drive motor
gear ②)
this year to change the distance between standard gears○ Results
Mechanism for transmission of torque
It was confirmed that the torque did not fluctuate under no-load conditions,from motor to cable winding drum
confirming that the measures considered were effective.

Time
10 s/div

Variation in drum drive torque under no load conditions(Before improvement)

10%/div

Torque10%/div

Torque1 drum rotation

Time
10 s/div

Variation in drum drive torque under no load conditions(After improvement)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.176(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Background• An evaluation is conducted to confirm the function of the posture control mechanism newly test-manufactured
this year and to evaluate its operation in combination with the telescopic pipe.
• To evaluate the effect of the improvements to the 14-stage telescopic pipe, which were made to suppress tilting
during extension, the amount of tilt and looseness during extension, which were evaluation items for FY2021,
will be evaluated, and the possibility of emergency retraction operation using depressurization will be verified.
○ Test planNo.

Test items/outline

Verification items

Target(Criteria)

Applicable
item

1[Verification of extension/retraction motion of telescopic pipe in vertical position]- Check whether the telescopic pipe can be extended or retracted.
(Check the effect of changing sliding parts (collars, dust seals))- Whether or not extension
is possible at the suppliedpressure (0.1 MPa)

- Whether or not extension is possible at the
supplied pressure (0.1 MPa)⑩

2[Verification of amount of tilt during telescopic pipe extension]- Check the amount of tilt during telescopic pipe extension.
(Compare with the telescopic pipe test-manufactured in FY2021)- Amount of tilt during
telescopic pipe extension- Is the amount of tilt improved compared tothe telescopic pipe test-manufactured in
FY2021?

⑦

3[Verification of looseness during telescopic pipe extension]- Check the amount of looseness during telescopic pipe extension.
(Compare with the telescopic pipe test-manufactured in FY2021)- Amount of looseness ateach stage of thetelescopic pipe

- Is the amount of looseness improved
compared to the telescopic pipe testmanufactured in FY2021?

⑧

4[Verification of operation of the posture control mechanism when the telescopic pipe is
extended]- Check if the position can be adjusted by the posture control mechanism while thetelescopic pipe is extended.

- Whether or not tilt
adjustment is possibleusing the posture control
mechanism- Whether or not operation within the rated
torque of each axis motor is possible⑨

5[Understanding the behavioral characteristics of the telescopic access equipment when it
sways]- To understand the swaying behavior of the telescopic access equipment when thetelescopic pipe is in its extended state- Swaying behavior of the tip — (Identify behavior only)of the telescopic pipe

6

[Verification of emergency retraction operation]- Check if emergency retraction by depressurization is possible with the telescopic pipe
extended.

- Whether or not retraction
is possible at reducedpressure (max -0.092
MPa)⑪- Whether or not emergency retraction by⑧
telescopic pipe/posture control mechanism
only is possible©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.177(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test piece/test system
The test was conducted by combining a newly test-manufactured posture control mechanism (forward/backward
mechanism, α-axis mechanism, β-axis mechanism) with the 14-stage telescopic pipe and cable winder to which
improvements were made this year. As in the previous year, scaffolding was set up around the apparatus so that the
behavior of the extended telescopic pipe could be observed.
α-axisβ-axis

4th level of scaffolding

Simulates the tilt axis of the retrieval arm(Manual tilt rotation operation is possible)

Forward/backward
movementmechanism

PC for posturecontrolmechanism
logging

14-stagetelescopic pipe

Operation panel
for posturecontrolmechanism

Operation panel forcable winder(with logging
function)

3rd level of scaffolding

2nd level of scaffolding

1st level of scaffolding
Tilt sensor
Test apparatus
Cable winder

Test apparatus

Operation table

Test system©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.178(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test piece/test system
About the test-manufactured posture control mechanism
The + direction and - direction of each axis of the posture control
mechanism are defined as shown in the figure, and the origin (zero α-axis
β-axis mechanism
mechanism
point) position of each axis is shown below.
- Forward/backward movement mechanism: minus direction travellimit- α-axis mechanism: Mounting surface of telescopic accessequipment- β-axis mechanism: Limit of movement in the minus direction+

α-axismechanism: 0°－
Direction of motion of+ β-axis mechanism－

β-axismechanism

Cable winder

Telescopic pipe
Investigation equipment
Forward/backward movement mechanism

α-axis mechanism

Investigation equipment mockup－+

Direction of motion of α-axis and β-axis

Forward/backward
movement mechanism

Horizontal posture©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.179(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.0: Verification of operation of posture control mechanism
Test results
It was confirmed that, with the telescopic pipe retracted, the posture control mechanism can be operated without
the torque of each axis motor exceeding 100%, whether the telescopic access equipment is in either a vertical or
horizontal posture. Although the operating range of the α-axis mechanism slightly failed to meet the required
specifications, it is expected that the required specifications will be met by reviewing the shape of the components
in the next fiscal year and thereafter. These results indicate that posture adjustment operations can be performed
without problems in the assumed operational sequence with the telescopic pipe in the retracted state.

Motor torque measurement results (vertical axis: torque, horizontal axis: time)
Vertical posture100

Forward/backward
movementmechanism+ directional
action- directional
action0100α-axismechanism+ directional
action- directional
action0+ directional
action- directional
action0+ directional
100
action100 + directional - directional
actionaction0-100

β-axismechanism

Horizontal posture
100

-100
- directional
action

100

0

0

-100

-100

+ directional - directional
actionactionMeasurement results of operating range
Required
specifications

Measurement
results

Forward/backward
movementmechanism

499 mm or
more

499 mmα-axismechanism*

0° to 13° or
more

0.4° to 13.6°

β-axismechanism

20 mm or more

22 mm

*Mounting surface of telescopic access equipment isdefined as 0°©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.180(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.1: Verification of extension/retraction motion of telescopic pipe in vertical position
Test purpose
The telescopic pipe test-manufactured this year has a harder dust seal than last year’s in order to suppress tilting
during extension and emergency retraction. Since this change has increased sliding resistance, conduct
verification to determine if extension/retraction motion can be performed without problems.
Test outline
Last year, the maximum supplied pressure was set at 0.1 MPa. This year, however, the pressure was increased tosuppress tilting during extension. During retraction, the motor torque of the cable winder was evaluated at thesame supplied pressure as last year.

Extension length [mm]Supplied pressure [MPa]Pressure supplied
Extension length

Extension length [mm]Motor torque [%]Motor torque
Extension length

Test results
Time [s]Time [s]Using the telescopic pipe to which improvements were made this year, it was confirmed that extension/retraction
motion could be performed without any problems even when the supplied pressure was increased from the previous
year. Although the motor torque exceeded 100%, no overload error occurred, and so it was determined that there wasno problem.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.181(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)

Black circle: Telescopic pipe
Gray: Cable winder: Positions plumb lines hungyxMeasuring height [mm]○ Test No.2: Verification of amount of tilt during telescopic pipe extension
Test purpose
Verify whether the telescopic pipe to which tilt suppression measures were applied this year shows any
improvements in the amount of tilt compared to the telescopic pipe of the previous year.
Test outline
The 14-stage telescopic pipe was fully extended, and as in the reproducibility verification test using the telescopic
pipe from the previous year, plumb lines were hung at two points, and the distance between the tip of each stageof the telescopic pipe and the plumb lines was measured to evaluate the amount of tilt.
Deviation of
14th stage tip:
207 mmDeviation of
14th stage tip:
108 mmTip of 10th stage
Tip of 8th stage

Tip of 5th stage

Amount of tip deviation at eachstage (x-direction) [mm]Tip of 6th stage

Amount of tip deviation at eachstage (y-direction) [mm]Test results
In the fully extended state, the tip deviation was (x, y) = (108 mm, 207 mm). In the reproducibility verification test
using last year’s telescopic pipe, (x, y) = (1 mm, 128 mm), indicating that the telescopic pipe test-manufactured thisyear tilted more. This suggests that this year’s telescopic pipe is more likely to fall over and to and retract less easily
during depressurization for emergency retraction.
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.182(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.3: Verification of looseness during telescopic pipe extension
Test purpose
Verify whether the telescopic pipe to which tilt suppression measures were applied this year shows any
improvements in the amount of looseness compared to the telescopic pipe of the previous year.
Test outline
Fully extend the 14-stage telescopic pipe and apply a force in the +x/-x direction to each stage to collapse thelooseness. Evaluation is performed by measuring the distance between the tip of each stage of the telescopic pipe
and a plumb line, in the same way as the amount of tilt was measured.
+x direction

A bending force is applied to thepipe in order to tilt the 3rd stage

Collapsing looseness by exerting
force in the +x direction-x direction

Collapsing looseness by exerting
force in the -x direction

Telescopic pipe after the looseness is collapsed by applying a bending force©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.183(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.3: Verification of looseness during telescopic pipe extension
Test results
The telescopic pipe developed in this fiscal year was test-manufactured with a design featuring narrower gaps
between the stage joints, but the results showed more looseness than with the pipe developed in last fiscal year.
381.7 mm

218.3 mm
218.3 mm 144.7 mm

−

+

−

+

Vertical position
Vertical position

Results of this year’s telescopic pipelooseness verification

Results of last year’slooseness verification©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.184(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.4: Verification of operation of the posture control mechanism when the telescopic pipe is extended
Test purpose
As consideration is being given to using α-axis and β-axis mechanisms for fine adjustment of the extension direction when
passing through the opening at the bottom of the reactor, verification will be performed to ascertain if the telescopic pipe
can be operated without problems even when extended.
Test outline
Two patterns of operation were evaluated: with the telescopic pipe fully extended and with the telescopic pipe extended tojust before the opening.
α-axis mechanism- Fully extended: Can the telescopic pipe be operated within the allowable tilt angle (-3.5
degrees) and α-axis motion limit when extended?
- Extended to just before the opening: Can the telescopic pipe be put in a position where it canpass through the opening while extended and tilted (For the y-direction, which cannot be
adjusted by the α-axis, the test was conducted while manually ensuring no tilt)
β-axis mechanism- Full extension: Is reciprocal movement within the operating range possible?
- Extended to just before the opening: Is operation within the operating range possible? (check
only movement in the + direction)

+1.7°

-3.5°

Adjustment direction by α-axis mechanismxyOperating range of α-axis mechanism when fully extended

When extended just before the opening©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.185(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.4: Verification of operation of the posture control mechanism when the telescopic pipe is extended
Test results (α-axis mechanism)
It was confirmed that there was no problem when the α-axis mechanism was operated while the telescopic pipe was
extended, with torque remaining within 100%. It was found that the α-axis mechanism can be used to fine-tune theposition for passing through the opening at the bottom of the reactor and for fine-tuning the position after full
extension.
0° → +1.7°

The α-axis was manipulated so that the cable winder angle changed
as follows:
vertical posture (0°) → + side movement limit (+1.7°) → -3.5° →vertical posture (0°)+1.7° → -3.5°-3.5° → 0°

Torque [%]<Results of operation verification at full extension height><Results of operation verification at height of just before the opening>
The α-axis mechanism was operated until the mockup investigationequipment was approximately at the center of the mockup opening.
(Operation completion position was determined visually)

Time [s]Torque [%]84 mm movement

Mockupopening

Before position
adjustment

After position
adjustment

Position adjustment by α-axis mechanism at the position just before the opening

Time [s]©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.186(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.4: Verification of operation of the posture control mechanism when the telescopic pipe is extended
Test results (β-axis mechanism)
When the β-axis mechanism was operated with the telescopic pipe extended, the starting torque sometimes
exceeded 100%, but it was confirmed that there was no problem because remained within 100% at all other times.
It was found that the β-axis mechanism can be used to fine-tune the position for passing through the opening at thebottom of the reactor and for fine-tuning the position after full extension.
22 mm → 0 mm

0 mm → 22 mm<Results of operation verification at full extension height>
Torque [%]The β-axis mechanism was moved from the origin (0 mm) to theoperating limit of 22 mm, and then returned to the origin.

<Results of operation verification at height of just before the opening>

Mockupopening

Investigationequipment mockup

After position
adjustment

Time [s]0 mm → 22 mm

Torque [%]The mockup investigation equipment was moved manually to a position where
it could pass through the mockup opening by operating the β-axis mechanism,and this was the starting position for operation. The operating range of the βaxis mechanism is 22 mm, but the tip moved about 31 mm. This is thought tobe a result of looseness or other factors causing tilting at the base when the
β-axis is moved.
Moved 31 mm

Before position
adjustment

Position adjustment by β-axis mechanism

Time [s]©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.187(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.5: Understanding the behavior of the telescopic access equipment during swaying
Test purpose
Determine the behavior of the telescopic pipe when it sways during extension.
Test outline
The end of the telescopic pipe was pulled a fixed distance (50 mm) and let go to allow it to sway freely, and theswaying behavior was captured and evaluated with a video camera. This was performed with the telescopic pipe
extended to the 7th stage and when fully extended. Note that the pipe was made to sway by pulling in the +x and+y directions, respectively.

50 mm

Hand removed

The pipe being pulled by hand
Tip position after extension
Making the telescopic pipe sway
©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.188(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.5: Understanding the behavior of the telescopic access equipment during swaying
Test results
When extended to the 7th stage (extension height: approx. 3500 mm), the telescopic pipe swayed at a frequency
of slightly over 1 Hz for only about 2 seconds, and when fully extended (extension height: approx. 7300 mm), it
swayed at a frequency of slightly less than 1 Hz and continued to sway for about 90 seconds. Meanwhile, it was
found that the swaying behavior did not change when the swaying direction changed.

<Extended to 7th stage>
The time taken to sway back and forthonce was slightly less than one second.
The swaying lasted only about two
seconds.

Swaying when extended to the 7th stage<Fully extended>
The time taken to sway back andforth once was a little over one
second.
The swaying lasted about 90
seconds.

Swaying when fully extended©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.189(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.6: Verification of emergency retraction operation
Test purpose
As an method of emergency retraction in the event that the cable winder stops working, consideration is being
given to creating a vacuum inside the telescopic pipe to retract it without winding the cable. Last year’s telescopic
pipe tilted during depressurization and failed to retract. This year’s telescopic pipe, with narrower gaps between
pipe sections, will be used to confirm whether emergency retraction is possible. It will also be verified whether
adjusting the posture of the pipe using the posture control mechanism can make emergency retraction easier.
Test outline
Two patterns were evaluated: without and with posture adjustment using the posture control mechanism. For theevaluation with posture adjustment, because adjustment with the posture control mechanism is only possible in thex-direction using the α-axis mechanism, posture adjustment in the y-direction was performed by the tester
manipulating a rope attached to the end of the telescopic pipe from above (y-direction posture adjustment for theactual equipment is to be performed using the tilt axis of the arm-type retrieval access equipment).

Direction of postureadjustment using αaxis mechanism

Direction of postureadjustment by
manipulating the rope©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.190(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Test No.6: Verification of emergency retraction operation
Test results
In the case of no position adjustment, as in the previous year, the telescopic pipe tilted when depressurized and emergency
retraction could not be performed.
For the evaluation with posture adjustment, the α-axis mechanism was able to adjust the position of the telescopic pipe, but
it was found that because the adjustment was made with the pipe depressurized and thus unable to maintain its posture,near vertical position there was a risk of rapid collapse to the opposite side. Since it is assumed that in a survey using
actual equipment, adjustment cannot be performed as in this test due to the presence of reactor internals around thetelescopic pipe, the influence of such structures needs to be examined in the future. When emergency retraction was
performed as in the previous year, the telescopic pipe did not retract completely and did not retract when pushed by hand (itprotrude about 170 mm compared to when fully retracted). It is thought that the cable was pushed down and jammed in thetelescopic pipe.
In the next fiscal year and beyond, studies will continue on tilt control measures to prevent the telescopic pipe fromcollapsing when depressurized. The impact on recovery operations of factors such as the pipe’s failure to fully retract will belooked into going forward.
① Tilting as a resultof extension② Depressurization
while tilted state
causes the pipe to tilt
further and collapse
rather than retracting③ Adjusting tip posture tovertical using the α-axis
mechanism

Risk of topplingThis range
measured toconfirm that theamount ofprotrusion is 170
mm

Diagram of telescopic pipe collapsing after depressurization

The pipe having failed to fully retract©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.191(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Summary of test results (1/2)

No.

0

Test items/outline[Verification of operation of posture control mechanism]- As a preliminary evaluation prior to the test, a check was
performed to confirm that each axis of the posture control
mechanism was able to operate with the telescopic pipe
retracted.

Verification items

Objective (evaluation criteria)

Operating range offorward/backward movement
mechanism

499 mm or more

Operability offorward/backward movement
mechanism

Ability to operate within the rated torque over
the operating range

Pass(Operable within the rated torque)

Operating range of α-axis

0° or below to 13° or above (closed state is 0°)

To be reviewed(Actual measurement: 0.4° to 13.6°. The shapeof the part will be reviewed in the future
because it makes contact, preventing fullclosure)Operability of α-axis

Ability to operate within the rated torque over
the operating range

Pass(Operable within the rated torque)

Operating range of β-axis

20 mm or more

Operability of β-axis

Ability to operate within the rated torque over
the operating range

1[Verification of extension/retraction motion of telescopic pipe
in vertical position]- Check whether the telescopic pipe can be extended or
retracted.
(Check the effect of changing sliding parts (collars, dust
seals))

Cable winder motor load2

[Verification of amount of tilt during telescopic pipe extension]- Check the amount of tilt during telescopic pipe extension.
(Compare with the telescopic pipe test-manufactured in
FY2021)

Amount of tilt at the tip of thetelescopic pipe at full
extension (horizontal distancefrom the center of the 1ststage pipe to the center of the
14th stage pipe)

Results
Pass (Actual measurement: 499 mm)

Pass(Actual measurement: 22 mm)

Ability to extend and retract without motor
overload errors

Is the amount of tilt at the tip of the telescopic
pipe less than or equal to the amount of tilt
(128 mm) of the telescopic pipe testmanufactured in FY2021?

Pass(Operable within the rated torque)

Pass(No motor overload error)

Fail(The amount of tilt was larger than that of thetelescopic pipe test-manufactured the previous
year)©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.192(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Summary of test results (2/2)

No.

3

4

5

6

Test items/outline[Verification of looseness during telescopic pipe extension]- Check the amount of looseness during telescopic pipe
extension.
(Compare with the telescopic pipe test-manufactured in
FY2021)[Verification of operation of the posture control mechanism
when the telescopic pipe is extended]- Check if the position can be adjusted by the posture control
mechanism while the telescopic pipe is extended.

[Verification of emergency retraction operation]- Check if emergency retraction by depressurization ispossible with the telescopic pipe extended.

[Evaluation of telescopic pipe behavior when the arm-type
retrieval access equipment sways]- The tip of the telescopic pipe is swayed to evaluate its
behavior. This is performed with the telescopic pipe
extended to the 7th stage and when fully extended.

Verification items

Objective (evaluation criteria)

Results

Is the looseness at the end of the telescopic
pipe in the direction of the anti-rotation rails
less than or equal to the looseness (218 mm)of the telescopic pipe test-manufactured in
FY2021?

Fail(The amount of looseness was larger than that of thetelescopic pipe test-manufactured the previous year)

Is the looseness at the end of the telescopic
pipe in the opposite direction from the antirotation rails less than or equal to thelooseness (144 mm) of the telescopic pipe
test- manufactured in FY2021?

Fail(The amount of looseness was larger than that of thetelescopic pipe test-manufactured the previous year)

Operability of α-axis whentelescopic pipe is fully
extended

Ability to operate within the rated torque by
moving the α-axis within the range of 6.5° to
13.0° (angle when the telescopic pipe is invertical position: 12.0°).

Pass(Operable within 100% of torque. It was confirmed that the αaxis is effective in fine-tuning the tip position when passing
through the opening at the bottom of the RPV)

Operability of β-axis whentelescopic pipe is fully
extended

Ability to operate within the rated torque over
the operating range

Pass(Drive torque may exceed 100%, but no overload error
occurs, and operation is possible within 100% torque except
during startup)

Can tilting during
depressurization becontrolled, allowing
emergency retraction
without posture adjustment?

Can be fully retracted using only
depressurization, without human assistanceor adjustment using the posture adjustment
mechanism

Fail(When depressurized, the pipe collapsed without retracting,the same result as last year)

Ability to retract thetelescopic pipe throughdepressurization

Can be fully retracted in the range of -92 kPa
to 0 Pa

To be reviewed(Depressurization to -85 kPa resulted in retraction of every
pipe stage, but the retraction was incomplete. The impact of
the inability to fully retract will be discussed in the future.)

For the x-direction, ability toadjust the posture verticallyusing only the α-axis,
without human assistancePresence of human assistance

To be reviewed(Although the tip can be adjusted vertically using the α-axis,
there is a risk that because the telescopic pipe is adjusted
without being able to maintain its posture, near vertical
position there is a risk of collapse to the opposite side)

Behavior of telescopic pipe
after being swayed while
extended

Understanding sway behavior―(The “―” was given because the purpose of this test is tounderstand the behavior, not to evaluate whether it is goodor bad.)Amount of looseness at the
tip of the telescopic pipe atfull extension©International Research Institute for Nuclear Decommissioning6. Implementation details

Units 2 and 3

No.193(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)○ Summary• The operation of the newly test-manufactured posture control mechanism was checked and it was confirmedthat there were no problems with its operation. The issue emerged that the operating range was narrower thanthe design value in some areas.
•

It was confirmed that the α- and β-axis mechanisms of the posture control mechanism can fine-tune the tip
position when the telescopic pipe is extended. Since it can be used to correct tip tilt and fine-tune the tip
position when passing through the opening at the bottom of the reactor, this will be reflected in future
operational studies.

•

In order to suppress tilting during telescopic pipe extension, the gap between the pipe sliding parts was
reduced, the dust seals were changed to harder ones, and tests were conducted to ascertain any
improvements. The results confirmed that there was no problem in extension/retraction motion of the telescopic
pipe. No improvements to tilting were achieved, with more tilt observed than last year.

•

With respect to emergency retraction, the telescopic pipe was tilted and failed to retract when the inside wasdepressurized, as was the case the previous year.

•

Hardware measures to reduce tilting and prevent tilting during emergency retraction might include making
some of the telescopic pipes from aluminum or reviewing their design. In terms of operational measures,
retraction could be performed by adjusting position using the posture control mechanism or by making use of
the surrounding structures. We will consider countermeasures in the next fiscal year and beyond.

©International Research Institute for Nuclear Decommissioning

Units 2 and 3

6. Implementation details

No.194(2) Development of the bottom access investigation method (telescopic pipe)5) Investigation details
Operation evaluation of telescopic access equipment (verification of ⑦ to ⑪)

Equipment put into horizontal position
using the tilt axis

Tip tilt
Telescopic pipe tilted during extension

Tip is adjusted to a vertical position
using the α-axis and the pipe is swayed©International Research Institute for Nuclear Decommissioning6. Implementation details

No.195(2) Development of the bottom access investigation method (telescopic pipe)6) Summary of results① Results obtained in FY2022
•

•
•
•

•

Based on the results through FY2021, the development plan was
reviewed and issues were identified.
Elemental tests were conducted to confirm the effectiveness of the
proposed countermeasures against the identified issues, and thecountermeasures were selected.
Telescopic access equipment reflecting the proposed
countermeasures was test-manufactured and tested to confirm its
functionality.
The results confirmed the basic operability of the telescopic accessequipment and its feasibility as a piece of equipment.
It was also confirmed that emergency retraction measures, etc., willcontinue to be an issue.
Operation using the equipment camera was discussed, and it was
confirmed that a method for measuring the dimensions of the RPV
opening and a method for detecting posture are needed.

② Issues for the future (FY2023 and beyond)•

The FY2022 results will be taken into account when reviewing thedevelopment plan and re-identifying issues. Anticipated issues are
given below.
① Study of countermeasures for emergency retraction② Improvements to the posture control mechanism③ Study of a method for determining the dimensions of the RPV
opening④ Study of a posture detection method for equipment⑤ Consideration of interfacing with the arm-type access equipment
currently under development in other projects

カメラ先端
Cameratip

Approx.
約8m
8m

Upper
surface of
グレーチング上面
grating

Picture of access using telescopic pipe

©International Research Institute for Nuclear Decommissioning