Subsidy Project of Decommissioning and Contaminated Water Management Started
From FY2020

Development of Technology for Further Increasing the
Scale of Fuel Debris Retrieval of Fuel Debris andReactor Internals(Technological Development for Ensuring Safety during Fuel
Debris Retrieval)
Final Report for FY2021
August 2022
International Research Institute for Nuclear Decommissioning(IRID)All rights reserved.
©International Research Institute for Nuclear Decommissioning (IRID)

No.1

Table of Contents
1.

2.
3.
4.
5.
6.

7.
8.

Purpose and Goals of “Development of Technology for Further Increasing the Retrieval Scaleof Fuel Debris of Fuel Debris and Reactor Internals (Technological development for ensuringsafety during fuel debris retrieval)”
Accomplishments of projects implemented in FY2017-2018 and FY2019-202020
Project Overview
Implementation Schedule
Project Organization
Implementation Items of This Project1) Development of an air-tight mechanism for large transfer containers
2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts
Summary
Specific Goals for Achieving the Purpose of the Project©International Research Institute for Nuclear Decommissioning1. Purpose and Goals of Project of “Development of Technology for Further Increasing the Retrieval Scale of
Fuel Debris of Fuel Debris and Reactor Internals(Technological development related to ensuring safety during fuel debris retrieval)”

No.2[Purpose of Project of Development of Technology for Further Increasing the Retrieval Scale of Fuel Debris of
Fuel Debris and Reactor Internals]
It is assumed that nuclear fuel has melted along with the reactor internals at Tokyo Electric Power Company
Holdings, Inc. (TEPCO) Fukushima Daiichi Nuclear Power Station (NPS) and exists in the form of molten fuel debris
in the Reactor Pressure Vessel (RPV) and the Primary Containment Vessel (PCV).
The fuel debris accumulated inside the RPVs and PCVs is estimated to be currently in a sub-critical state; however
the plant itself is in an unstable condition unlike its initial design, since the Reactor Building (R/B), RPV, PCV, etc.
have been damaged due to the accident. Therefore, it is necessary to retrieve the fuel debris in order to maintain the
sub-critical state, and to prevent diffusion of radioactive materials.
Against this background, this project is intended to conduct studies based on the “Mid-and-Long-Term Road-map
Towards Decommissioning of TEPCO’s Fukushima Daiichi Nuclear Power Station” (hereinafter “Mid-and-Long-Term
Road-map”), aiming towards the implementation of large-scale fuel debris retrieval in coordination with theengineering and project management activities undertaken by TEPCO. The development results of this project will
be used in TEPCO’s engineering activities.
The purpose of this project is to smoothly carry out decommissioning and contaminated water management at the
Fukushima Daiichi NPS by implementing projects that support technological development contributing to thedecommissioning and contaminated water management based on the Mid-and-Long-Term Road-map and the“FY2020 Research & Development Plan” (the 75th Secretariat Team Meeting for Countermeasures for
Decommissioning and Contaminated Water Treatment), and in addition, to enhance the standard of science andtechnology in Japan.
As part of the “Technological development related to ensuring safety during fuel debris retrieval”, element
technologies for confinement of radioactive materials, reduction of exposure dose of the workers, etc. which areessential to ensure the safety of the public and workers during fuel debris retrieval work, will be developed.
[Project goal]
The goal of the project is to conduct studies towards accomplishment of a further increased scale of fueldebris retrieval according to the Mid-and-Long Term Road-map.

[Duration of Project] December 2020 to March 2022 (16 months)©International Research Institute for Nuclear Decommissioning2. Accomplishments of Projects implemented in FY2017-2018 and FY2019-2020

No.3

The results of past subsidy projects that are related to this project are provided below.
(1) Top-access method for transferring the unitized large structures[Main results of studies conducted as part of upgrading of fundamental technology for retrieval of fuel debris
and internal structures (hereinafter “Fundamental technology upgrade”: implemented in FY2017-2018)]••

Top
container

An image of establishing the access route (removal of interferences) was createdand element tests were conducted using simulated structures of the reactor
bottom to verify the feasibility of the removal procedure.
The retrieval duration (throughput) was estimated by assuming details of theprocedure such as the unit to be cut out, the shape and thickness of the portion to
be cut, the cutting method, etc.

Container craneFuel debris
Retrievalcell

Fuel debris retrieval cell
crane

Equipmentloading, etc.

CRD housing
Clamp part

DSP
Well

Dedicated cask

Canister
Inside Nuclear
ReactorRemoval of large structures from thereactor bottom

Abrasive Water Jet(AWJ) nozzle

The method of cutting the structures inside the PCV, containing them in unit cansand transferring them is quite challenging in terms of work efficiency and timerequired for the work.

RPV

Shielded container
Unit can (UC)PCV
Fuel debris

Items implemented in the Project of Development of Technology for Further Increasing the Retrieval Scale of Fuel
Debris of Fuel Debris and Reactor Internals (hereinafter, “Project of Further Increasing the Retrieval Scale of Fuel
Debris”: implemented in FY2019-2020)]
Verifying the feasibility of the method for transferring as large structures as possible and then cutting them in a separatebuilding©International Research Institute for Nuclear Decommissioning2. Accomplishments of Projects Implemented in FY2017-2018 and FY2019-2020

No.4(1) Top-access method for transferring the unitized large structures[Concepts of the new top access method (removing and transferring the unitized structures)]
The concept of the method for removing and transferring the unitized structures, which was studied under “Project of Further Increasing the Retrieval
Scale of Fuel Debris”, is indicated below.
✓ Individual unitized structures will be transferred.
✓ The reactor core will be cut into multiple units, and lower hemispherical dome of the reactor bottom will be separated in its entirety from the RPV.
✓ The shielding and air-tightness of the objects to be transferred will be ensured by means of a container or access route or a combination of both.
✓ The work of cutting the structures that are retrieved and enclosing them in a container will be carried out in a building that is at a distance fromthe R/B.

[Study items under “Project of Further Increasing the Retrieval Scale of Fuel Debris”]
The following items were studied in the FY2019-2020 Subsidy Project (Project of Further Increasing the Retrieval Scale of Fuel Debris).
✓✓

Study of method for transferring (transfer route) the
R/B
原子炉建屋
unitized structures.
Study of the method of disassembling the reactor bottom
Crane
揚重機
and related element tests
連絡通路
Passageway
Cutting tool切断ツール
transportationequipment
搬送装置

Transportation
搬送台車 cart
回収容器 container
Collection
搬送装置
transportationequipment

Assisting
arm
補助アーム

接続
Connection
sleeveスリーブ

RPVbottomRPV下鏡

グレーチング
Grating
insulationmaterial保温材

取り出し装置Retrievalequipment

Cutting切断ツール
tool (withgripping
and cutting(把持と切断機能あり)
function)

Expanded
増設建屋 building
The air-tight mechanism of thecontainer has not been studied indetail⇒New Development [Refer to 6.1)]
Dual
lid
二重蓋
(Not illustrated in the figure as(開放中のため図示せず)
the lid is being opened)
Largetransfer
大型搬出容器
container(dedicated(輸送専用容器)transportation
container)

CRD
housing
CRD.Hサポート
supportbeam,
ビーム、ブラケット
bracket

HCU配管
HCU
pipes

Signalcables
信号ケーブル類

Conceptual drawing of interference removal from the reactor bottom

Method for transferring (transfer route) the unitized
structures, that is being studied©International Research Institute for Nuclear Decommissioning2. Accomplishments of Projects Implemented in FY2017-2018 and FY2019-2020

No.5(1) Top-access method for transferring the unitized large structures[The major issues in the method for transferring the unitized structures, which was studied under “Project of Development of Technology for
Further Increasing the Retrieval Scale of Fuel Debris”]

The major issues studied in the “Project of Development of Technology for Further Increasing the Retrieval Scale of Fuel
Debris” Project are shown in [1] to [5] as below. Refer to the results of the FY2020 Final Report of the (August 2021.
Issue [3]: Crane

Issue [4]： Criticality control

・Method of handling large
structures
・Maintenance of the lifting
R/B
原子炉建屋
machineIssue [2]：Shielding and air-tightness ofthe passageway
・Shield thickness based on mass
reduction of the passageway andtaking the building load (load on
the refueling floor) as well into
consideration
・Ensuring air-tightness whiletransferring the structures
Issue [1]：Method of removing the reactor
bottom
Cutting
tool
切断ツール
搬送装置
transportationequipmentCollection
回収容器
搬送装置
containertransportationequipment

Assisting
arm
補助アーム
RPV下鏡
RPV
bottomGrating
insulation
グレーチングmaterial
保温材

CRD
housing
CRD.Hサポート
ビーム、ブラケット
supportbeam,
bracketCutting
tool
切断ツール
(with
gripping(把持と切断機能あり)
and cutting
function)

HCU配管*CRD pipes

Signalcables
信号ケーブル類

・Method of criticality control
until storage in containers

Crane
揚重機

連絡通路
Passageway

取り出し装置Removalequipment

Expanded
増設建屋
building[New Development under thisProject]
・ Air-tight mechanism of thecontainer lid
・ Method of criticality control
during transfer after storage incontainers

Transportation
搬送台車 cart

接続
Connection
sleeveスリーブ

Dual lid
二重蓋(Not
illustrated in the figure as the lidis(開放中のため図示せず)
being opened)
Large transfer container
大型搬出容器(dedicatedtransportation
container)(輸送専用容器)

Issue [5]： Cooling andhydrogen・Method of cooling duringtransfer(Need for cooling)・Hydrogen countermeasuresduring transfer*Control rod drive©International Research Institute for Nuclear Decommissioning2. Accomplishments of Projects Implemented in FY2017-2018 and FY2019-2020

No.6(2) Access tunnel[Main results of studies conducted as part of Upgrading of Approach and Systems for Retrievalof Fuel Debris and Internal Structures (hereinafter “Approach & Systems Upgrade”: implemented
in FY2017-2018)]•
The expanded building outside R/B and the PCV will be connected with an
Expanded
増設建屋
access tunnel having a shielding function to build the carrying-in/out route.
building•
The load of the access tunnel will be borne by the outer wall of R/B and thebiological shielding wall, in order to maintain within the load limit for the floor
surface on the first floor.
•

The tunnel will be assembled outside the R/B, and will be introduced and set up
by means of remote operation so as to reduce worker exposure.

The above-mentioned items were studied, element tests related to delivery wereconducted by simulating the shape and dimensions and feasibility wasverified.

PCV

Opening of
biological shield

Location of R/B
outer wall

Access tunnel
アクセストンネル
Overview of access tunnel
Opening of biological shield

Access tunnel(actual outer appearance)

Slide part
Desk study
The slide part needs to be studied by loading
simulation (New Development [Refer to 6.2)
[1]])

Implementation status of element tests©International Research Institute for Nuclear Decommissioning2. Accomplishments of Projects Implemented in FY2017-2018 and FY2019-2020

No.7(2) Access tunnel[Items implemented under “Project of Development of Technology for Further Increasing the Scale of Fuel Debris
Retrieval” (implemented in FY2019-2020): [1] Study on the method of connecting the access tunnel sleeve (AT sleeve)]•

Multiple welded connection structure proposals were studied and a comparative evaluation was carried out. The following Case
1 was studied as the main proposal.

•

After studying the structure of the AT sleeve, tests related to welded connection were implemented.

Case 1Case 2
AT sleeve welded part

AT sleeve welded part

Cross-section

Workability

Confinement ofcontamination inside
the AT sleeve
Number of steps
involved ininstallation
Groove alignment(inside theequipment hatch)• Partially removing the scaffolding from inside theequipment hatch• Welding the AT sleeve to the edge of the equipment
hatch shell• Welding the lower side of the AT sleeve to the innersurface of the equipment hatch shell via the scaffolding
seal cover• Partially removing the scaffolding from inside the equipment
hatch• Welding the AT sleeve to the edge of the equipment hatchshell• Installing a plate above the scaffolding, and welding it to thelower side of the AT sleeve and the inner surface of theequipment hatch and the equipment hatch door

Very good
Welding all connection parts

Very good
Welding all connection parts

Good
Removing the scaffolding, pressure
resistance test conducted onceGood

Acceptable
Removing the scaffolding, pressure
resistance test conducted twice
Very good

The connecting portion between the scaffolding seal coverand the portion of the scaffolding that is removed, needs to be
examined.

It is assumed that the scaffolding plate is only kept

Welding work
efficiency

Good

Good

Comprehensive
evaluation

Good

Acceptable

Illustration of welding the AT sleeve to the equipment
hatch©International Research Institute for Nuclear Decommissioning2. Accomplishments of Projects Implemented in FY2017-2018 and FY2019-2020(2) Access tunnel

No.8

Vertical displacement*[Items implemented under “Project of Development of Technology for Further
Increasing the Scale of Fuel Debris Retrieval” (implemented in FY2019-2020): [2]Study of the AT sleeve structure]

Location

Level from
OP** [mm]Evaluation
point [mm]Verticaldisplacement[mm]

Top edge of
hatch

12905

13490

0.12

•

The PCV and access tunnel were connected by means of the AT sleeve. The AT sleeve supports the loadof the access tunnel, and in addition, absorbs displacements in the event of an earthquake by means of thedisplacement absorption mechanism installed on the PCV side.
•
The AT sleeve including the displacement absorption mechanism was studied.
⇒ Considering the amount of displacement in the event of an earthquake, displacement of ±12.5mm
needs to be secured* in the horizontal direction.
There is a distance of approximately 350 mm between the surfaces of the applicable parts.
Since existing technologies such as bellows structure, etc. is not applicable to this situation, a new
structure was studied.

PCV side
12.5mmHorizontal displacement*
Level from
OP** [mm]Evaluation
point [mm]Verticaldisplacement[mm]

Top edge of
hatch

12905

13490

12.5

Center of
hatch

11260

11180

9

Bottom edgeof hatch

9675

9760

7

Location

アクセストンネル
Access tunnel

スリーブ
SleeveDisplacement
変位吸収機構absorption
mechanism

PCV
Biological
生体遮蔽壁
shielding wall
(BSW)
(BSW)

Approx.
350 mm
約350mmSliding section
Load

荷重支持点
supporting
point

Sleeve (tunnel) side
Proposed structure of the displacement
absorption mechanism being studied

Details of the displacement absorption
structure

A detail study of the displacement absorption mechanism was conducted as part of the“Project of Development of Technology for Further Increasing the Scale of Fuel Debris
Retrieval” Project.
⇒ The feasibility of the displacement absorption mechanism needs to be verified by atrial manufacture and element tests. (New Development [Refer to 6.2) [2]])約1800mmApprox.
1800 mm(BSW
thickness)(BSW厚さ)Example of the structure of the part connecting
the PCV and the access tunnel[Supplementary information] The tunnel and the sleeve are fixed and move together with the R/B as awhole in the event of an earthquake.
(The displacements during an earthquake are absorbed by the displacement absorption mechanism)Research Method
Institute
NuclearDecommissioning*Set up based on the contents of the report on Subsidy Project of Decommissioning and Contaminated Water Management in the FY2015 Supplementary Budgets©International“Development of Assessment
for forSeismic
Resistanceand Impact ofPressure Vessel and Containment Vessel” (Refueling floor additional equipment: 6100 ton, Seismic motion: 900Gal)3. Project Overview

No.9

3. 1. Collaboration with other projects
Development of Fuel Debris Retrieval
Method➢ Development of side access method➢ Development of top access method
Sharing of analysis needs/results
Sharing of investigation needs/results

Sharing of technological challenges

Characterization offuel debris

Investigation inside
PCV

Technological Development related toEnsuring Safety during Fuel Debris Retrieval

Development of technology forinvestigation inside RPVDevelopment of analysis and estimation
technology for characterization of fueldebrisCoordination of containing/transfer
and methods

Technological development related toensuring safety during fuel debris
retrieval

Development of technology for detailed
investigation inside PCVContaining, Transfer
and Storage
Technology
Development of technology forcontaining, transfer and storage offuel debris

Sharing of the status of study

Gradually Increasing the
Scale of Fuel Debris
Retrieval・Sharing of safety scenarios
・Coordination of work steps

Coordination of containing/transfer and methods

Development of technology forgradually increasing the scale of fueldebris retrieval

Development of Safety System

Development of liquid/gas phase systems, criticality control technology

Solid Waste
Research and development for treatment anddisposal of solid waste

In this project, joint meetings were held as required in coordination with the above-mentioned projects.
©International Research Institute for Nuclear Decommissioning3. Project overview

No.10

3. 2 Development items involving solicitation and implementation policy
Development items involving
solicitation
1) Development of an air-tightmechanism for large transfer
containers

Implementation policy

Corresponding
slidesWith respect to retrieving fuel debris and reactor internals, the method of transferring theunitized large structures is being studied in order to improve the throughput for the top
access as part of the development being undertaken since FY2019. In order to transfer
large structures, it is necessary to develop large transfer containers with a function forpreventing the spread of contamination and shielding function for high radiation items
stored in containers.

No. 14～66

Upon studying the pre-conditions for the large transfer containers and the required
development items, an air-tight mechanism for the lid of the large transfer container will be
developed. And, the criticality control method for the period from after collection of thestructures until they are stored, will be studied.

2) Development of technology forconnecting heavy structures foraccessing PCV and theconfinement structure for theconnection parts[1] Technology for connecting heavy structures for accessing PCV
As the new access equipment (access tunnel, cell, etc.) to be installed in the R/B is heavyequipment weighing several hundred tons, technology for connecting the heavy structures
to PCV by remote operation will be developed.

No. 70～96[2] Confinement structure for the connection parts
As the equipment to be newly installed needs to be equipped with the function of absorbing
displacements in the event of an earthquake in addition to a confinement function for theconnection parts, a displacement absorption structure for the PCV connection parts will be
developed.

No. 97～127©International Research Institute for Nuclear Decommissioning3. Project overview

No.11

3. 3 Points to be noted while executing this project
The points to be noted while executing the plans under this project are described below.
[Points to be noted]
The air-tight mechanism of large transfer containers for transferring structures, technology for remotelyconnecting the new access equipment to be connected to PCV and for confining the connection parts,

which is important for ensuring the safety of the public and the workers while retrieving fuel debris on alarge scale, are studied.
During the study, development is carried out while considering the handleability in terms of thefollowing and maintenance method of the equipment that is operated remotely.

・As the equipment is installed in areas with high radiation, as a general rule, maintenance is carried out
remotely.
・The contamination of the equipment and the required decontamination need to be taken into
consideration.

・Work area is limited for maintenance work.
・Waste generated during maintenance work needs to be minimized as much as possible.
・Installation and handling of criticality monitoring system need to be considered.

©International Research Institute for Nuclear Decommissioning4. Implementation Schedule

No.12

Implementation
Schedule of “Development of Technology for Project of Development of Technology for Further Increasing the Scale of Fuel Debris 実施スケジュール
Retrieval of Fuel
燃料デブリ・炉内構造物の取り出し規模の更なる拡大に向けた技術の開発（燃料デブリ取り出し作業時の安全確保に関わる技術開発）
Debris and Reactor Internals (Technological development for ensuring safety during fuel debris retrieval)”
Broad 大分類
classification

Small
小分類
classification

大型搬出容器の気密機構
1.１.Developmentof an airの開発
tightmechanism forlarge transfer containers

a. Conceptual
概念検討 study

FY20202020年度
2021年度FY2021Apr
Jun 7月Oct 11月
Nov 12月
Dec 1月Jan Feb
Jan Feb
Jul Aug
Apr May
Jul Aug
Nov 12月
Dec 1月Oct 11月
4月 May
5月 6月
8月 Sep9月 10月2月 Mar
3月 4月
5月 Jun
6月 7月
8月 Sep9月 10月2月 Mar3月

Remarks
備考[Legend]【凡例】

Conceptual
概念検討 study

Planned：計画
Moving the schedule

Element test plan
要素試験計画：前倒し着手を検討
ahead is being considered：実績
Actualtest planb. Element
要素試験計画

Test
preparations / test manufacturing of testing equipment
試験準備/試験装置試作

Test preparations /c. Test
試験準備/
manufacturingoftesting equipment
試験装置試作tests
d. Elementl
要素試験

Element
tests
要素試験

Study of criticality

Study of criticality control methods
臨界管理方法検討

e. control
臨界管理方法のmethods
検討

Summaryまとめf. Summary
まとめ
アクセス用重量構造物の2. 2.
Developmentof
接続構築技術及び接続部
technology
for connectingの閉じ込め構造の開発
heavy
structures for①
アクセス用重量構造物のaccessing
PCV and the
接続構築技術confinement
structure forthe connection parts(1) Technology forconnecting heavy
structures for accessing
PCV

Conceptual study
概念検討

a. Conceptual
概念検討 study
Element test plan
要素試験計画b. Element
要素試験計画
test plan
Test preparations / test manufacturing of testing equipment
試験準備/試験装置試作

Test preparations /c. Test
試験準備/
manufacturingoftesting equipment
試験装置試作
d. Element
要素試験
tests

Element
tests
要素試験

まとめ
Summarye. Summary
まとめ

Conceptual study
概念検討(2)②Confinement
structure
接続部の閉じ込め構造
for the connection parts

Conceptual study
a. 概念検討
Element test planb. 要素試験計画

Element test plan
要素試験計画

Test preparations /Test preparations / test manufacturing of testing equipment
試験準備/試験装置試作

Test manufacturingc. 試験準備/of testing equipment
試験装置試作Element tests
d. 要素試験

Element
tests
要素試験
Summary
まとめ

Summarye. まとめ

Major
milestones
主要なマイルストン

Annualreport年度報告Interimreport中間報告

Final report 最終報告
Submissionof report on actual results
実績報告書提出©International Research Institute for Nuclear Decommissioning5. Project organization
International Research Institute for Nuclear
Decommissioning (IRID)➢Coordination of overall planning and technology
management➢Coordination of technology administration including
technology development progress management

Hitachi-GE Nuclear Energy, Ltd.
[Element test, technical development](1) Development of an air-tight mechanism for largetransfer containers(2) Development of technology for connecting heavy
structures for accessing PCV and the confinement structure
for the connection parts[Sub-contracting details]
・Technological development related to air-tight mechanism of the largetransfer containers,
technological development related to transferring (rotating) heavy
structures,
technological development related to confining the connection parts(Toko Corporation)
・Implementation of tests related to air-tight mechanism of the largetransfer containers(Mitsubishi Heavy Industries, Ltd. (Former Mitsubishi Power, Ltd.))
・Designing assistance related to air-tight mechanism of the large transfer
containers(JTEC)・Designing assistance related to development of heavy structures foraccessing PCV(Hitachi Plant Construction, Ltd. )No.13

Tokyo Electric Power Company
Holdings, Inc.
➢Coordinations for site application

Project teams to cooperate fortechnological development
Development of Fuel Debris Retrieval
MethodDevelopment of Technology for Gradually
Increasing the Retrieval Scale of Fuel Debris

Development of Safety Systems (Liquid/Gas
Phase Systems, Criticality Control
Technology)

Development of Technology for Investigation
inside RPVDevelopment of Technology for Detailed
Investigation inside PCV (Field Validation of
the Technology for Detailed Internal
Investigation using X-6 Penetration)

Development of Technology for Detailed
Investigation inside PCV(On-site Demonstration of Technology for
Detailed Internal Investigation Considering
Deposit Measures)

Development of Analysis and Estimation
Technology for Characterization of Fuel
DebrisDevelopment of Technology for Containing,
Transfer and Storage of Fuel Debris

Research and Development for Treatment
and Disposal of Solid Waste©International Research Institute for Nuclear Decommissioning６．Implementation Items of This Project

No.141) Development of an air-tight mechanism for large transfer containers
Development items involving
solicitation

Implementation policy

Items to be explained Remarks

1) Development of an air-tight mechanism
for large transfer containers

With respect to retrieving fuel debris and reactor internals, the method of transferring the unitizedlarge structures is being studied in order to improve the throughput for the top access method as partof the development being undertaken since FY2019. In order to transfer large structures, it isnecessary to develop large transfer containers with a function for preventing the spread ofcontamination and shielding function for high radiation items stored in containers.
Upon studying the pre-conditions for the large transfer containers and the required development
items, an air-tight mechanism for the lid of the large transfer container will be developed. And, thecriticality control method for the period from after collection of the structures until they are stored, will
be studied.

2) Development of technology forconnecting heavy structures toaccessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures for accessing PCV
As the new access equipment (access tunnel, cell, etc.) to be installed in the R/B is heavy equipment
weighing several hundred tons, technology for connecting the heavy structures to PCV by remote
operation will be developed.
[2] Confinement structure for the connection parts
As the equipment to be newly installed needs to be equipped with the function of absorbing
displacements in the event of an earthquake in addition to a confinement function for the connection
parts, a displacement absorption structure for the PCV connection parts will be developed.
Targets of the element tests
conducted
during this development
本開発での要素試験対象

可動フランジMovable flange

Upper
lid
上蓋

Lower
下蓋 lidDedicated
輸送専用容器transportation
container

Conceptual drawing of a large transfer container (dedicated
大型搬出容器(輸送専用容器)概念
transportation container)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.15

1) Development of an air-tight mechanism for large transfer containers
With respect to retrieving fuel debris and reactor internals, the method of transferring theunitized large structures is being studied in order to improve the throughput for the top accessmethod as part of the development being undertaken since FY2019.
To implement this method, it is necessary to separate the structures from PCV and transfer
these large structures. In addition, large transfer containers to be used for transferring thelarge structures are required for development of a function of preventing contamination spread
and a shielding function for the high radiation items stored in containers.
Upon studying the pre-conditions for the large transfer containers and the required
development items, an air-tight mechanism and shielding structure for the lid of the largetransfer container are developed, the leakage rate (evaluation method is investigated as
required) was estimated, and a conceptual study of the system for transferring the structuresfrom the R/B (or the expanded building) by means of the large transfer containers are
conducted. Additionally, element tests related to the air-tight structure of the lid were performed
to confirm technical feasibility. Along with that, studies on ensuring criticality safety of the largetransfer containers used for containing the whole unit of large structures on which fuel debris isadhered were conducted. Based on these studies and development, the onsite applicability of
the large transfer containers was evaluated and issues were clarified.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.16

1) Development of an air-tight mechanism for large transfer
containers
Project of Development for Upgrading Fundamental Technology(implemented in FY2017-2018)[Study of the method for finely cutting inside PCV]
➢ Implementation of element tests using simulated reactor bottom
structures➢ Estimation of throughput, identification of issues

CRDハウジング
CRD housing
clamp part
クランプ部

AWJノズルAWJ
nozzleRemovalof large structures from
炉底部の大型構造物の撤去
the reactor bottom

R/B
原子炉建屋

Project of Development of Technology for Further Increasing theRetrieval Scale of Fuel Debris (implemented in FY2019- 2020)[Study of the method of transferring the unitized structures]➢ Implementation of element tests related to disassembling
the reactor bottom➢ Conceptual study related to the large transfer containers➢ Study of the method of criticality control until storage incontainers

Crane
揚重機
Passageway
連絡通路

Retrieval

取り出し装置equipment

Expanded
増設建屋 building

Transportation
搬送台車 cart
Connection
接続
sleeve
スリーブ

Dual
lid
二重蓋
(Not
illustrated in the figure as the lid is open)(開放中のため図示せず)
Largetransfer container
大型搬出容器(dedicatedtransportation container)(輸送専用容器)

Targets of the element tests to be
本開発での要素試験対象
conducted in this project
Movableflange可動フランジ
Upper
lid
上蓋

Implemented in this project[Feasibility verification of the large transfer container lid]
➢ Development of the air-tight mechanism for the container lid and element tests➢ Study of the method of criticality control after storage in containers (during transfer)

Items studied under the Project for Development of Fuel Debris Retrieval Method➢➢

Feasibility verification of the large transfer container body (manufacturability, etc.)
Feasibility verification of the method of cutting large structures and the transportation equipment

下蓋lid
Lower
Dedicatedtransportation
輸送専用容器
container

Conceptual drawing of a large transfer container
大型搬出容器(輸送専用容器)概念(dedicatedtransportation container)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.171) Development of an air-tight mechanism for large transfer containers[Issues]•••

Conceptual study of the air-tight structure considering the shielding of the lid portion of the large transfer container
Feasibility verification of the lid portion air-tight structure that was studied
Method of criticality control until the structures to which fuel debris is adhered are enclosed in the large transfer containers and transferred to a
separate building for storage[Implementation Details]• Study on the prevention function of spread of contamination (air-tight structure) of thelarge transfer container for transferring large structures or high radiation
contaminants is conducted.
•Study on the shielding structure of the large transfer containers is
conducted taking into consideration that high radiation structures are stored inthem.
• Conceptual study is conducted for evaluating (evaluation method is investigated as
required) the leakage rate from the lid portion and a test plan is developed after
examining the test conditions.
• Element tests are conducted to verify the feasibility of the lid portion air-tight structurethat is studied.
(During the test, the plan is to verify the air-tightness when the upper lid and lower lid areconnected and the air-tightness of the lid portion when the lower lid and container areconnected, for preventing contamination of the lower lid surface.)•The method of criticality control until the structures to which fuel debris is adhered are
enclosed in the containers and transferred to a separate building for storage, is studied.

Targets of the element tests to be
conducted in this project
Movable flange[Expected outcome]•Air-tight structure taking into consideration the shielding of the lid portion of the large transfer
container will be presented.
•The criticality control method for the period from after collection of the structures until they are stored,
will be presented.

Upper lid

Lower lid

Dedicatedtransportation
container
Conceptual drawing large transfer
container (dedicated transportation
container)©International Research Institute for Nuclear DecommissioningNo.18

6. Implementation Items of This Project

Targets of element tests conducted during this development

1) Development of an air-tight mechanism for large transfer containers
Upper lid

[Application method for the dedicated transport container]

Lower lid
Retrieval
取り出し装置equipment

Dedicated transportation container dual lid structure (proposed)

増設建屋 building
ExpandedReference:
Illustration of the
参考：容器本体のイメージ
main body of the container

Weight: approx.
重量：約390ton
520 tonΦ8m

搬送台車 cart
Transportation

容器イメージ
Illustrationof container

Dual
lid
二重蓋
(Not
illustrated
in the(開放中のため図示せず)
figure as the lid is open)

7.5m

Large transfer
container
大型搬出容器(dedicated transportation(輸送専用容器)
container)

炉底部燃料デブリ
Fuel debris
at the reactor bottom

After collecting thestructures the upper andlower lid are lowered(Connected to thecontainer)

Upper andlower lid arelowered

Φ6m
Φ7m
主要寸法
Main
dimensions

Illustration of collection at
炉底部回収イメージ
the reactor bottom

・A dual lid of Φ6m is not possible with the existing
technology⇒Will be newly developed due to issues such as
airtightness.

Method for transferring the unitized structures, thatis being studied

As the container is large, it is difficult to
overpack for preventing spread ofcontamination⇒ Using dual lids can prevent contamination of
the container surface and thus an overpack is
not required.

Upper & lower lid
are connected tothe container

The connectionof upper andlower lid isreleasedContainertransfer

Transfer procedures for the dedicated transportation
containers (proposed)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.191) Development of an air-tight mechanism for large transfer containers[Overview of large transfer containers]
The large transfer containers are studied based on the method of transferring the unitized large structures and theresults of the conceptual study related to large transfer containers conducted under Project of Development of Technology
for Further Increasing the Scale of Fuel Debris Retrieval implemented in FY2019-2020.
Large transfer containers are used in 3 scenarios, namely, [1] in the expanded building, [2] for on-site transportation,and [3] in the newly constructed building. Their use and required functionalities differ in each scenario. This research
focuses on the use in the expanded building.
Area in which the large containers are used

R/B
原子炉建屋

Passageway
連絡通路

Retrievalequipment
取り出し装置Expanded
増設建屋
building

Fine cutting cell

Transportation
搬送台車 cart

接続
Connection
スリーブ
sleeveDual lid
二重蓋(Not
illustrated in the figure(開放中のため図示せず)
asthe lid is open)

大型搬出容器Largetransfer container(dedicatedtransportation container)(輸送専用容器)

Carry-in cell(A) Use inside the expanded building[Work details]
・The connection parts of the structures are severed, and the unitized large
structures are transferred from the PCV by lifting them up using a crane.
・After the structures are moved over the operation floor using the transportation
cart, they are lowered down using the crane in the expanded building, stored
in the large transfer containers and delivered.
・Maintenance is carried out either through remote operation or from themaintenance cell.

(B) For on-site transportation[Work details]
・The structures placed inside the largetransfer containers are transported onsite up to the newly constructed building.

To the storage facility

Newly constructedbuilding

Crane
揚重機

Fine cutting Canister Transport cask

(C) Use inside the newly constructed building[Work details]
・The structures are removed from the large transfer containers.
・The structures are finely cut and enclosed in canisters, and theseare further placed inside the transport cask.
・The transport cask is delivered and stored at the storage facility.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.20

1) Development of an air-tight mechanism for large transfer containers[Basic policy and specifications related to the large transfer containers]
・Containers with common specifications are used regardless of the structures that will
be stored in them.
・Additional shield is installed depending on the structure (radiation dose).
⇒ Element tests are conducted on the air-tight mechanism of the large transfer
containers with common specifications.
・The containers are used repetitively as dedicated transport containers⇒ Rubber O-ring is used considering the vibrations, etc. during transport and that thedual lid will be opened/closed multiple times.

Structures

Large transfer
containers

AdditionalshieldDuring on-sitetransportation

Item

Container specifications

Remarks

Use applications

On-site transport container

Items to be transported

Dryer, separator, upper grid plate, reactor core, reactor bottom, etc.

Approximate dimensions of thecontainers with common specifications

Φ6000 × H7500 [mm]Shape of the container is such that typical structures can be stored in it

Approximate weight of the containers
with common specifications

520 [ton]

Only the main body of the container and the dual lid (not including thestructures)

Maximum dose rate of contents

1000 Sv/hShielding thickness (γ rays)

280 [mm]Shielding thickness (neutron rays)

100 [mm]Pressure within the cell-400 [PaG]

Connected to the inside of the PCV (red zone) which is -400[Pa], with lid
closedContainer surface design temperature

130 [℃]

Considering heat generated by the fuel debris

Number of use

To be determined

Multiple uses are being considered

Main material

Low alloy steel

Material of sealed part

Rubber O-ring

Separately added 130 [mm] shield for structures with a high radiation dose

Considering the vibrations, etc. during transport and that the dual lid will be
opened/closed multiple times.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.211) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (1/7)]
The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.
(1) Preparation for carrying-in the container: Removing the safety lid

Enlarged view of Part A

Expanded building
Building cover

Movable flange
Primary boundary-400[Pa]***R

Transportation cart

Passageway
Upper lid

-400[Pa]***Upper lid Primary boundary
Water seal

Work container
Shielding cart

[Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

Isolation
sheet

Primary boundary (areaenclosed by red line)

Sealed part [1]Since air-tightness is ensured by means of
the upper lid (and safety lid), this zone isassumed to be “Y” which is extremely nearto “G”
Safety lid

Safety lid -150[Pa] -64[Pa](2) Carrying-in the container: Carrying-in the large transfer container

Bellows

Sealed part
[3]

Y(G)*

Fixed flange(Fixed to the expandedbuilding)
Primary boundary
Safety lid

Part A(1): Preparation for carrying-in the container: Removing the safety lid

Enlarged view of Part A

Movable flange
is raised

R
Work container
Shielding cart

Sealedpart [3]Transportation cart

Upper lid
Part A

Isolation
sheet

Since air-tightness is ensured bymeans of the upper lid, this portionis assumed to be “Y” which isextremely near to “G”.
Container (with lower lid)
Large transfer
container

Y(G)*Sealedpart [2]Lower lid

G(R)**

Container iscarried-in(2)-1: Raising the movable flange(2)-2: Carrying-in the large transfer container(The container moves only in the horizontal direction)* Assumed to be "Y" which is extremely near to "G"** When the dedicated transportation container is re-used, the inside of the container may not be “G”.
*** Value of pressure is assumed©International Research Institute for Nuclear DecommissioningNo.22

6. Implementation Items of This Project1) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (2/7)]
The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.

(3) Connecting the container: Connecting the upper lid and lower[Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

Enlarged view of Part A

lid (container)

Movable flange isloweredR
Sealed part [3]Sealed part [1]Work container

Sealed part [5]Shielding cart

Transportation cart

Primary boundary(area enclosed by red line)

Y(G)*Isolation sheet

Sealed part [4]Y(G)*(3)-1: Lowering the movable flange(3)-2: Connecting the upper lid andlower lid (container)

Large transfer
container(4) Lifting the dual lid, opening thecontainer

G(R)**

Sealed part [6]Part AIf the space between the upper lid and lower lid is not completely
air-tight, the upper surface of the lower lid gets contaminated.
Hence it needs to be air-tight to some extent.

Upper and lower lid
are raised
Enlarged

Shielding cart

Transportation cart

Sealed part [5]Work container
Dual lid ofcontainer

Y(G)*Sealed part [1]Attached to the lower
lid by means of a hook

R

Part A
Large transfer
container

Y(G)*Sealed part [4]* Assumed to be “Y” which is extremely near to “G”** When the dedicated transportation container is re-used, the inside of the container may not be “G”.

(4): Lifting the dual lid to open the container©International Research Institute for Nuclear DecommissioningNo.23

6. Implementation Items of This Project1) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (3/7)][Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.
(5) Completing the opening of the container

Enlarged view of Part A

Primary boundary (area enclosed by red line)
Shielding cart

Transportation cart

Sealed part [1]Work container

R

Dual lid ofcontainerY(G)*Large transfer container

Part A

Sealed part [4](5): Opening the container
Enlarged view of Part A(6) Placing the structure in the container

Lowering of thestructures
Shielding cart

Transportation cart

Sealed part [1]Work container
Dual lid ofcontainerR
Large transfer container* Assumed to be “Y” which is extremely near to “G”

Part A

Y(G)*Sealed part [4](6): The structure is lowered and placed in the container©International Research Institute for Nuclear DecommissioningNo.24

6. Implementation Items of This Project1) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (4/7)][Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.
Enlarged view of Part A(7) Lowering the dual lid

Sealed part [5]Y(G)*Shielding cart

Primary boundary (areaenclosed by red line)

Transportation cart

Sealed part [1]Upper and lower lid
are lowered

Work container

Dual lid of container

Y(G)*
R

Sealed part [4]Large transfer container

Part A(7)-1: Examining and cleaning on the sealed surface (removing trash, etc.)(7)-2: Lowering the dual lid(8) Closing the dual lid of the container

Enlarged view of Part A
R

Shielding cart

Sealed part [3]Transportation cart

Sealed part [1]Sealed part [5]Work container

Y(G)*Sealed part [4]Dual lid of container

Sealed part [6]Large transfer
container

Y(G)*

R

Part A(8): Closing the lid of the large container* Assumed to be “Y” which is extremely near to “G”©International Research Institute for Nuclear DecommissioningNo.25

6. Implementation Items of This Project1) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (5/7)][Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.
(9): Separating the container: Decoupling the upper lid and lower lid

Primary boundary (area enclosed by red line)
Shielding cart

Transportation cart

Upper lid
Work container

Dual lid ofcontainer

Since air-tightness is ensured by meansof the upper lid, this portion is assumed tobe "Y" which is extremely near to "G".

Part A

Enlarged view of Part A

Large transfer container

R

Movable flange
is raised

Sealed part [3]Sealed part [2]Y(G)*The lower lid of the container presses down the
O-ring with its own body weight and secures it in place.
* Assumed to be “Y” which is extremely near to “G”

Sealed part [6]R(9)-1: Raising the movable flange(9)-2: Decoupling the upper lid and lower lid©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.26[Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

1) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (6/7)]

The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.
Enlarged view of Part A(10): Transferring the container: Transferring
the large transfer containerR

If the space between the lower lid and the container
is not completely air-tight, the outer surface of thecontainer gets contaminated. Hence it needs
to be air-tight to some extent.

Sealed part [3]Primary boundary(area enclosed by red line)
Shielding cart

Sealed part [2]Transportation cart

Container is
moved

Y(G)*

Sealed part [6]RWork container

Container (with lower lid)
Large transfer
Dual lid of container container(10)-1: Moving the large container to thenext cell which is the lid closing cellPart A

Structurecollection cell

Lid closing cell

Delivery cell

Sealed part [6]R(10)-2: Moving the large container to the lid closing cell

* Assumed to be “Y” which is extremely near to “G”©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.27

1) Development of an air-tight mechanism for large transfer containers[Steps involved in operating the dual lid for transferring the unitized structures (7/7)][Notes]
R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

The steps involved in operating the dual lid for transferring structures and the primary boundary are indicted below.
(11) Installing the secondary lid: Installing asecondary lid for on-site transportation

Enlarged view of Part A
The bolt isfastenedY(G)*Shielding cart

Primary boundary(area enclosed by red line)

Transportation cart

Y(G)*Work container

Dual lid of Large transfer
container container

R

Secondary lid

The container istransported after
contamination
inspection and pressure
resistance test

Sealed part [7]Sealed part [6]Part A
Lid closing cell

Structure collection cell(11)-1: Installing a lid (secondary lid) on the large
container for on-site transportation(11)-2: Moving to the delivery cell after contamination
inspection and pressure resistance test

Delivery cell(12) Transporting to a separate building: Transporting the largetransfer containers to a separate building

Fine cutting cellWork container
Shielding cart

Transportation cart

Primary boundary(area enclosed by red line)

Large transfer containers are transported toa separate building with their secondary lids
installed. (Transportation method is being studied.)
Dual lid of container

Large transfer container

Carry-in cell

Safety lid* Assumed to be “Y” which is extremely near to “G”

Fine cutting Canister

To the storage facility

Newly constructedbuilding

Transport cask

(12): Transporting large transfer
containers to a separate building©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.28[Notes]1) Development of an air-tight mechanism for large transfer containers R: Red (high contamination) zone
Y: Yellow (moderate contamination) zone
G: Green (low contamination) zone

[Issues in the operation of the dedicated transport container lid (1/2)]

Based on the steps involved in operating the dual lid, the issues in operating the lid at the main steps were clarified.
1. Carrying-in and connecting the container

2. Opening the container
Raising theupper/lower
lids

3. Closing the container
Raising the
movable flange
Upper lid
Sealed part (3)Sealed part (5)Step diagram

Lowering of
movableflange4. Separating the container

Raising theupper/lower
lids

Sealed part (3)Movable flange
FixedflangeLower lid

Sealedpart (1)Sealed part (5)Sealed part (2)Container body
Sealed part (6)Sealedpart (4)

Details➢ The container body to which the lower lid isconnected is carried in and aligned so that it
is positioned directly below the movable
flange.
➢ The movable flange is lowered, andconnected to the container body. (Upperand lower lids are connected as well)A)
B)

Main issues

C)
D)

E)

Method of carrying-in the container
Method of determining the container
position
Lid opening and closing mechanism(Connection of upper and lower lid)
Method of verifying the connection(connection between the movable flange
and container body, and the upper andlower lids)
Air-tightness of the sealed parts (Sealed
parts [1] [4] [5])➢ The upper and lower lids are lifted up in acoupled state to open the container.

Sealed part (6)➢ The upper and lower lids are lowered in acoupled state after the structures arecollected in the container.
➢ The upper and lower lids are decoupled, thelower lid is mounted on the container bodyand upper lid is mounted on the movable
flange.
A)

B)
A)

Sealed part (5)Air-tightness of sealed part [5] whenraisedC)

Lid opening and closing mechanism(Attachment and detachment of upperand lower lid)
Method of verifying the connection(connection between the lower lid andcontainer body, and the upper lid andmovable flange)
Air-tightness of the sealed parts (Sealed
parts [3] and [6])➢ The movable flange is raised, and thecontainer is separated.

A)
B)

Criteria for determining whether thecontainer can be separated
Air-tightness of the sealed part (Sealed
part [2])©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.29

1) Development of an air-tight mechanism for large transfer containers[Problems in the operation of the dedicated transport container lid (2/2)]: Scope of testing
during this project

ID:

Problems

Details

Study

Testing

1

Method of carrying-in the container

The plan is to carry-in the container by mounting it on a vehicle. The method for doing this will be studied.

Done

ー

Application ofexisting
technologies

2

Method of determining thecontainer position

As the alignment of the container position is difficult if it is mounted on a vehicle, installing a position
adjustment mechanism between the vehicle and the container will be considered.

Done

ー

Application ofexisting
technologies

3

Lid opening/closing mechanism

The method for connecting and attaching/detaching the upper lid and lower lid will be studied, and its
feasibility will be verified through element tests.

Done

Done

4

Connection checking method

The method for remotely checking the connection will be studied and verified through element tests.
[This method can be used for the following:]
Connection between the upper lid and lower lid, the lower lid and container body, and the upper lid andmovable flange

Done

Done

5

Sealing of the sealed partThe sealing method will be studied, and sealing performance will be verified through element tests.
The following 3 locations that are related to the upper lid and lower lid that are mounted remotely, will betested.
・Sealed part [3]: Between movable flange and upper lid
・Sealed part [5]: Between upper lid and lower lid
・Sealed part [6]: Between lower lid and container

Done

Done

6

Air-tightness of sealed part [5](between the upper lid and lowerlid) when raised

A sealing method with which the air-tightness of the sealed part can be maintained when the upper lid andlower lid are lifted as a whole, will be studied.
⇒Since the air-tightness of sealed part [5] can be maintained as long as part D (refer to No. 37 for details)
which is the gap that occurs due to the operation of the dual lid, is air-tight, it is assumed that there will not
be any problem even at the time of lifting up. Hence testing is not carried out.

Done

ー

Criteria for determining whether the container can be separated and transferred will be studied and theirvalidity will be verified through element tests.

Done

Done

7

Criteria for determining whether thecontainer can be separated

Remarks

Interchangeablewith abovementioned No. 5⇒ Element tests for ID 3 to 5 and 7 will be conducted.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.30

1) Development of an air-tight mechanism for large transfer containers[Test plan]
Items to be monitored,measured and recorded

Criteria⚫ Verification of the movement of the lid opening/closing mechanism byoperating the hook
⚫ Verification of the connection between the upper lid and lower lid when thelower lid is installed and the upper lid is lifted up by means of the hook, andverification of the gap, etc.

➢ Abnormal noise, rattling, etc.
➢ Connecting portion between
the upper and lower lid➢ Gap (Extent to which the Oring is flattened)➢ Moves normally.
➢ As per the dimensions.
➢ Meets the O-ring
specifications and iswithin the design range

Verification of
the connection
checking
method⚫ Remote checking of the connections between the upper lid and lower lid, thelower lid and container body, and the upper lid and movable flange➢ Gap (Extent to which the Oring is flattened)➢ Meets the O-ring
specifications and iswithin the design range

Air-tightness
performance⚫ Verification of the air-tightness at each step
⚫ Verification of air-tightness in case the part to be connected to is misaligned(It is verified that air-tightness is maintained even if there is misalignment, andthis is reflected in the study of accuracy specifications for container positionalignment in the expanded building.)⚫ The sealed part [3]: between movable flange and upper lid, sealed part [5]:between upper lid and lower lid and sealed part [6]: between lower lid andcontainer will be verified.

ID:

Items

1

Validity of the lid
opening/closing
mechanism

2

3

4

5

Confirmation of
reproducibility
Criteria for
determining
whether thecontainer can beseparated

Details⚫ Tests will be conducted multiple times to verify whether the items to bemonitored are reproducible⚫ It will be remotely verified that the upper and lower lids are installed and thehook gets disconnected when the lifting beam goes on descending.

➢ Gap (Extent to which the Oring is flattened)➢ Pressure➢ Meets the O-ring
specifications and iswithin the design range➢ Leakage rate: 0.1[vol%/h] or less
(Details are provided later.)Same as items 1 to 3 above➢ Position of the hook
➢ Sagging of the wireー

➢ The hook comes offfrom the lug of thelower lid.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.31

1) Development of an air-tight mechanism for large transfer containers[Items to be verified through element tests (Scope of simulation of actual equipment)]
ID:

Equipment

1)

Movable flange➢

Diameter 9300, height 1600, weight 150[ton]2)Fixed flange➢

Diameter 11100, thickness 375, weight 170[ton]3)Upper lid➢

Diameter 6800, height 800, weight 50[ton]4)

Lower lid➢

Diameter 6800, thickness 280, weight 80[ton]5)➢Container

Inner diameter 6000, thickness 280, height 7500, weight390[ton]6)

Lifting hook➢

Diameter 500, height 1500

7)

Test container

Mock-up specifications (approximate
dimensions)

Actual equipment specifications (approximate dimensions)➢ー

For development and test manufacturing
Method of simulation for the test

Diameter 8000, height 1100, weight 30[ton]➢Actual equipment shape is simulated.

ー➢Not simulated this time.

➢

Same as actual equipment (part of it simplified)➢

Actual equipment shape is simulated.

➢

Same as actual equipment➢

Actual equipment shape is simulated.

ー

ー

➢

Diameter 500, height 1500➢

Shape of the hook is simulated.

➢

Inner diameter 6000, thickness 32, height 200➢

Only the diameter of the container is simulated.

6) Lifting hook3) Upper lid

2) Fixed flange

4) Lower lid

1) Movable flange

・The height of the container body that does not have an impact on theairtightness mechanism of the dual lid is not simulated. (Only the diameterof the container is simulated. The structure is such that pressure can beapplied)・The actual movable flange moves up and down, but since this time thepurpose is to verify air-tightness, the movable flange is fiixed to thecontainer (fixed flange), and the dual lid side is moved up and down tocheck the sealed part.

6) Lifting hook3) Upper lid5) Container
1) Movable flange(Fixed this time)4) Lower lid5) Test container
Illustration of the actual structure

Illustration of the mock-up structure©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project1)

Development of an air-tight mechanism forlarge transfer containers[Items to be verified by means of the element tests(Items for verification of air-tightness)]

An overview of the components (equipment) of the dual lid,
and the items for verifying air-tightness by means of element
tests are indicated below.
Equipment

Fixed flange

Overview

Port attached to the expanded building forming the boundary➢
Movable flange

Upper lid

Lower lid

Container

➢

➢
➢

➢
➢

➢
➢

The movable flange moves when the container is mounted. It is normallyconnected to the upper lid and forms the boundary.
At the time of connecting the container, it connects with the container andforms the boundary.

It is connected to the movable flange and forms the boundary.
It is connected to the lower lid and plays the role of providing a dual lid.

It is connected to the upper lid and plays the role of providing a dual lid.
It is connected to the container. It prevents spread of contamination andshields against dose from the structures.

It is connected to the movable flange and forms the boundary.
It is connected to the lower lid and the secondary lid and plays the role ofan on-site transport cask.

No.32

Sealed part [3]Lifting hook

Movable flange
Sealed part [5]Fixed flange

Water seal

Bellows

Sealed part [1]Sealed part [2]Upper lid

Air-tightness
verification items

Sealed part [4]Sealed part [6]Sealed part [7]ShieldingPresent(Equivalent toexpanded building)Present(Equivalent toexpanded building)

Lower lid
Air-tight connecting part (Seal No.)

Container body
Reason for selection

Upper part of fixed flange[1]

Lower part of fixed flange[2]Upper part of fixed flange[1]

Lower part of fixed flange[2]Upper lid[3]This portion is mounted remotely. Its sealing needs to beverified.

Container[4]

As long as the container is aligned, it moves only in thevertical direction at a fixed position and hence it isdetermined to have a lower priority.

Movable flange[3]This portion is mounted remotely. Its sealing needs to beverified.

Lower lid[5]Upper lid

[5]

Container[6]This portion is mounted remotely. Its sealing needs to beverified.

Movable flange[4]

As long as the container is aligned, it moves only in thevertical direction at a fixed position and hence it isdetermined to have a lower priority.

Lower lid

[6]This portion is joined remotely. Its sealing needs to beverified.

Secondary lid[7]This part is relevant to the secondary lid and falls within thescope of verification on the container side.

AbsentPresent

Present

Secondary lid

It is connected to the container and serves as the sealing boundary duringtransportation.

Present

Container[7]

Safety lid

It is connected to the fixed flange and forms the boundary during normal
conditions.

Present(Equivalent toexpanded building)

Fixed flange[8]

The fixed flange is installed during construction. It makes asimple vertical movement. Hence it is determined to have alower priority.

This portion is joined remotely. Its sealing needs to beverified.

The connection is within the green zone and hence it isdetermined to have a lower priority.

©International Research Institute for Nuclear Decommissioning

Conceptual study of the parts that do not undergo a sealing verification test will be conducted.

6. Implementation Items of This Project

No.33

1) Development of an air-tight mechanism for large transfer containers[Items to be verified by means of the element tests (Details of items for verification of air-tightness)]
The approach towards the sealed part that is to be verified for air-tightness and the method for securing air-tightness
are given in the table below.
ID:

Sealed part

1

Sealed part [3]2Sealed part [5]3Sealed part [6]Air-tight connection⚫

Between upper lid andmovable flange⚫

Between upper andlower lid⚫

Between the lower lid
and container

Method for ensuring air-tightness

Operational steps at which air-tightness
needs to be secured➢

The upper lid presses down the O-ring with
its own body weight to secure theprescribed flattening of the O-ring.

➢➢(3) Before connecting the container(9) After separating the container➢

The upper lid presses down the O-ring with
its own body weight to secure theprescribed flattening of the O-ring.

➢➢(4) Lifting the dual lid, opening thecontainer(7) Lowering the dual lid

The lower lid presses down the O-ring with
its own body weight to secure theprescribed flattening of the O-ring.

➢➢(2) Carrying-in the container(10) Transferring the container➢

Remarks➢

The method of ensuring that both O-rings are flattened tothe prescribed extent, when the O-rings are pressed downat the same time as the sealed part [5] between the upperand lower lids, has been studied.

➢

The method of ensuring that both O-rings are flattened tothe prescribed extent, when the O-rings are pressed downat the same time as the sealed part [3] between the upper
lid and movable flange, has been studied.

➢

The air-tightness of the container is secured only withsealed part [6] until the lid for on-site transportation(secondary lid) is installed.

111

Sealed part[3]
Sealed part
[5]
Sealed part
[6]

Sealed part
[5]
Sealed part
[6]
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.34

1) Development of an air-tight mechanism for large transfer containers[Required specifications for the dual lid air-tight mechanism]
The air-tightness performance required for the steps involved in using large transfer containers is given below.
Inside the expanded building

Illustration

To be tested

Securing air-tightness with only the
body weight of the lower lid

On-site transportation
Securing air-tightness by tightening thebolts of the lid
Lid for on-site transportation (secondary lid)
Bolt

Y(G)*

R
Sealed part [6]Sealed part [7]R

Required airtightness
performance

・During the work of collecting debris in large transfer
containers inside the expanded building, if confinement canbe achieved with red and yellow cells, then there is no
problem.

・On-site transportation is possible with the lower lid and the lidfor on-site transportation (secondary lid) installed on the large
container.
→ Air-tight function that meets the on-site transportation
standards is required.

Policy forstudying airtightness
performance

The criteria for determining the leakage rate will be establishedtaking into consideration that the load of decontamination work,
etc. will reduce if the contamination on the upper surface of thelower lid and on the surface of the container is reduced.

Exposure will be assessed while referring to the specificationsof the spent fuel casks, etc., to establish the criteria for
determining leakage rate that meets on-site transportation
standards.

Policy forelement tests

The large container and the dual lid need to be handled while
they are connected to the main cell (red zone). Hence thepossibility of remote operation and monitoring will be verified
through element tests.

While tightening the bolts of the lid for on-site transportation,
since the container is not connected to the red zone, the levelof difficulty of work described on the left is assumed to becomparatively low, and hence only desk study will be carriedout.

Measures in
response torisks

Since the transient state continues until the lid for on-sitetransportation is installed, confinement will be secured within
the primary boundary without considering the impact ofearthquakes, etc.

Earthquakes, overturning etc. could occur during on-sitetransportation up to the separate building. Hence measures in
response need to be studied in the future.

* Assumed to be “Y” which is extremely near to “G”©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.35

1) Development of an air-tight mechanism for large transfer containers[Approach towards the criteria for determining leakage rate]
The criteria is established based on the design basis of the cell, assuming that the leakage rate with respect to the air-tightness
performance of the large transfer containers inside the expanded building is about the same as the leakage rate permitted in thecells inside the boundary.
As shown in the table below, since 0.1[vol%/h] is a conservative standard for the cell, at the present point in time, the criteria isestablished based on 0.1[vol%/h].
ID:Standards pertaining toleakage rate

1

0.25[vol%/h]

JIS Z4808 Radioactive glove compartment2

0.1[vol%/h]

JAEA
Application for permission to change the nuclear fuel material specifications at Oarai
Research Institute (facility used)3

0.3[vol%/h]

SourceSubsidy Project for the Decommissioning and Contaminated Water Countermeasures in the FY2014
Supplementary Budget
Fundamental Technology

40.1[vol%/h]

FY2016 Final Report

Air management at the nuclear facility (hot cell)[Status of sharing of information with other projects]•
The permissible leakage rate in the isolation room for detailed investigation inside Unit 2 PCV is established at 0.05[vol%h] by
applying the ISO10648-2 Class 1 values.
•
ISO10648-2 are clean room standards. If there is leakage on the inside of the clean room and the isolation room with positive
pressure, contamination is likely to be diffused on the outside. Hence it is assumed that strict conditions are selected.
•
Since there is negative pressure inside of the large transfer containers, the leakage is internal, and it is assumed that
contamination is less likely to diffuse to the outside.
•
Since the operation inside the expanded building is being verified this time, and as there is a boundary outside the container as
well, the above-mentioned standards are assumed to be sufficiently conservative.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.36

1) Development of an air-tight mechanism for large transfer containers[Approach towards the criteria for determining leakage rate]
Part D is formed under the following condition considering the steps involved in using
the actual large transfer containers.
・ (1) Since Part D is not contaminated prior to collecting the structures, even if there isleakage in other areas, Part D does not get affected.
・ (2) The red area in Part D is contaminated after collecting the structures, but as it issmall in size, even if there is leakage in other areas, its impact is extremely small.
・ In (2), after connection the space between the upper lid and the lower lid (Part A)
becomes yellow area with a pressure of -150[Pa], which is higher than the pressure(-400[Pa]) inside the container that is contaminated after collecting the structures.
→ The contamination does not spread from Part B to Part A, and thus does notcontaminate the surface of the lower lid. However, there is major leakage fromPart A to Part B due to which the pressure becomes equal giving rise to the risk ofcontamination. Hence leakage needs to be managed using Part A as reference.
→Part A between the upper lid and the lower lid is considered as the reference size
(Volume of Part A： 11180[L] ⇒ 0.1[%vol/h]： 12[L/h])D
A
Sealed part [3]Y(G)*-150[Pa]

Sealed part [4]Sealed part [5]B

Sealed part [6]R-400[Pa]Movable flange is lowered
R

R

Sealed part [1]Sealed part [1]Y(G)*Sealedpart [3]Y(G)*Volume of Part A

11800L

Volume of Part B

6300L

Volume of Part C

31000L

Volume of Part D

101L

Sealed part [4]Sealed part [3]G(R)**

Sealed part [4](1)Connecting the upper lid and lower lid (container)
by lowering the movable flange

Y(G)*Sealed part [6]

R

Y(G)*

(2): Closing the lid of the large container after collecting the structures* Assumed to be "Y" which is extremely near to "G"** When the dedicated transportation container is re-used, the inside of the container may not be “G”.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.37

1) Development of an air-tight mechanism for large transfer containers[Approach towards the standard size for establishing the permissible leakage rate]
The permissible leakage rate was established on the previous page using the size of Part A as reference. The following table indicates thesize of each part and the leakage rate when those sizes are used as reference.
If the leakage rate is to be established conservatively, Part D, which is small in size, should be considered as reference from among thelocations indicated in the following table. 101×0.01＝ approx. 0.1[L/h] would be the criteria for determining the leakage rate in that case.
However, Part D indicates a gap that is generated due to the use of the dual lid. It is not a boundary that must be secured.
Part A, which is considered to be next conservative, is a boundary that must be secured. Hence the leakage rate was calculated
considering Part A for the reference size.
MU testActual Equipment
Remarks

Volume [L]Leakage rate
[L/h]Volume [L]Leakage rate [L/h]Part A

11800

12

11800

12

Part B

6300

6198000198

Part C

31000

31

209800210Part D

101

0.1

101

0.1

Sealed part [3]The volume is larger than Part A in the actual
equipment

Part D is not a boundary that must be secured.
(Impact due to leakage in other areas is extremely
small)

Sealed part [5]Sealed part [6]Part D
Test container

Upper lid

Upper lid

Part A

Test container

Part B

Lower lid

Part C

Lower lid

Test container

Test container©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.38

1) Development of an air-tight mechanism for large transfer containers[Method of calculating the permissible leakage rate]
The permissible leakage rate is calculated using the following formula (*).
Upper lid

Q=

V𝑇20 𝑃2 𝑃1 V𝑇20 𝑃𝑎𝑡𝑚2 𝑃𝑎𝑡𝑚1−−[𝑃𝑎・ 𝐿Τ𝑠]
Δ𝑡 𝑇2 𝑇1 ＋ Δ𝑡
𝑇2
𝑇1

𝑞=

𝑄
[𝐿Τ𝑠]
101325Here, the leakage rate (Pa・L/s) is in terms of Q: 20°C
P1: Gauge pressure (Pa) of the test specimen when measurement starts
P2: Gauge pressure (Pa) of the test specimen when measurement ends
Patm1: Atmospheric pressure (outside pressure) （Pa） when measurement
startsPatm2: Atmospheric pressure (outside pressure) （Pa） after measurement
startsΔt : Time from start of measurement to end of measurement (s)V: Internal volume (L) of the test specimen
T20: Reference temperature 293 (K)T1: Absolute temperature (K) of the gas inside the test specimen whenmeasurement starts
T2: Absolute temperature (K) of the gas inside the test specimen whenmeasurement ends
q: Leakage rate (L/s) in terms of 20℃ and 1 atmospheric pressure(*)： Based on the pressure change and pressurization method
stipulated in JIS Z 2332 - Leak testing method using pressurechange.

Sealed part (3)Sealed part (5)Part D(Volume: 101L)[3] Pressure measurement[2] Closed
valve

Sealed part (6)Test container

Upper lid

Enlarged view of Part D

P1[1] Application of pressureusing nitrogen cylinder
Pressure is applied up to
400PaG and maintained

T1
Test container Lower lid[4] Temperature
measurement

Part D(Volume: 101L)[1] Pressure measurement

Maintained for aperiod of 15 minutes

Upper lidP2
[1] Application ofpressure using
nitrogen cylinder

T2
Test container[2] Temperature measurement

Lower lid

<Illustration of test procedures>©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.39

1) Development of an air-tight mechanism for large transfer containers
135°

System diagram[Air-tightness verification test:
Schematic drawing]

Thermocouple: Type K

Flange lifting part(4 locations)

Test specimen side 4 sets + 1(For measuring theenvironmental temperature)

Extension lead wire

Thermocouple connector

Hose

Container main bodylifting part(4 locations)

For measuring fine pressure
difference
Precision pressure gauge GC-15

Lifting attachment for
the upper lid andcamera insertion part(4 locations)

Test specimen side 4 sets

USB cable

4 × Rc1*

Data logger: GL240

225°

45°
For Part A(For reference)

For the surrounding
environment

Nitrogen cylinder

Micro-manometer
FlangePressure gauge for measuring
the ambient atmosphericpressure
Reference: GC31 (with analog
output)Barometer

Thermometer

Laptop computer

4×Rc1

Thermometer
Water receptacle forchecking leakage

For Part D
Micromanometer

For Part B(For reference)

NitrogencylinderMicro-manometer

Thermometer

Nitrogen cylinder
Upper lid

2×Rc1/ 2
Installed at 45° witha 6[mm] inclination

Container main bodyAir-tightness verification test
(Illustration of pressure resistance test)*Rc: Taper pipe thread

Thermometer2-Rc1/2©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.40

1) Development of an air-tight mechanism for large transfer containers[Element test procedures]
The test cases handled during the dual lid element test are indicated below.
This test is made up of the following 3 test cases.
・ In Test 1, each sealed part is checked for leakage using water to verify the air-tightness performance of the parts formed by thedual lid and movable flange.
・ In Test 2, the connection between the upper and lower lid is verified while monitoring with a camera. Further, the air-tightness ofthe sealed part is verified by applying pressure on Part D. (By testing Part D, all sealed parts to be tested this time are verified.)
・ In Test 3 is an offset test. The upper and lower lids and the movable flange are placed in an offset position, in other words, theupper and lower lids and the movable flange are positioned beforehand such that it is difficult to make them fit together, and then atest similar to Test 2 is conducted.

Dual lid element test
Test
No.

Name of the test

1

Air-tightness performance verification test ofeach part

Test details

Remarks

The parts are checked for leakage using water,
and the air-tightness of sealed parts [3], [5], and [6] is verified
individually.

2Comprehensive function test

・The fitting of the upper and lower lids, and whether or not they can belifted and positioned is verified (including verification of the extent offlattening of the O-ring by means of dimensional check).
・ The air-tightness of the sealed part is verified. (The leakage rate is
calculated from the results of measuring the pressure andtemperature, and air-tightness is verified.)

3

Offset test

The upper and lower lids and the movable flange are offset 50[mm] inthe circumferential direction, and a test similar to Test 2 is conducted.

Monitoring by means ofcamera©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.41

1) Development of an air-tight mechanism for large transfer containers[Test 1: Air-tightness performance verification test of each part (conducted once for each part)]
Air-tightness of each sealed part is confirmed individually, and upon confirming that there is no leakage, the comprehensive function test is conducted.
1. Lower lid + container flange sealing performance verification items
1

Levelness verification of the container and flange set: 5 [mm] inclination
between both outer diameters

2O-ring [6] set

3

Lower lid set

4

Leakage check using water, for 15 minutes at 400[PaG]

Rough drawing
Leakage check bypouring water

O-ringAir pressure 400Pa

2. Upper lid + lower lid sealing performance verification items
1

O-ring [4], [5], [6] set

2Upper lid set

3

Balance removal

4

Leakage check using water, for 15 minutes at 400[PaG]

Removal of upper and lower lid

2

Movable flange set, levelness measurement: Movable flange sheet
surface3Upper lid set

4

Leakage check using water, for 15 minutes at 400[PaG]

5

Removal of upper lid

6

Cleaning of each component and site

Container flange

Rough drawing
Leakage checkby pouring
water

Upper lid

Air pressure
400Pa

Lower lid

O-ring3. Upper lid+ movable flange, movable flange + container sealing
performance verification items
1

Lower lid

Container flange

Rough drawing
Leakage checkby pouringwater

O-ringMovable flange
Upper lid

Air pressure 400Pa

Container flange©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.42

1) Development of an air-tight mechanism for large transfer containers[Test 2: Comprehensive function test (conducted 3 times for each part)]
Test
No.

2-1

Target

Test details

Criteria

Positioning, fitting test
(No misalignment)[1] The extent of deviation of the upper lid in the vertical and horizontal directions ischecked when the upper and lower lids are set.
[2] The upper lid and lower lid are lifted up simultaneously using the lifting lug for theupper and lower lids.
[3] The lifting lug for the upper and lower lids is slowly raised (raised about
100[mm]).
[4] The fitting of the hook is verified using a camera (the hook touches down on thelower lug).
[5] The upper lid and lower lid are raised further (raised about 1200 [mm]).
[6] They are lowered once again and it is verified whether they can be positionedsmoothly without any noise or damage from Part R of the movable flange andcontainer lid.
[7] Right after positioning (when the lifting lug for the upper and lower lids is at a
position 100[mm] above), they are slowly lowered to confirm whether the hookcomes off.
[8] After the hook comes off, the upper and lower lid installation data is acquired
once again, to verify the variation in installation accuracy.

・During the lifting and lowering
work, fitting must happensmoothly without any noise,damage , etc.
・Attachment and detachment of
the upper and lower lids must
be possible smoothly without
any noise, damage, etc.

Checking the fitting of thehook with a camera

Remarks

Checking the release of thehook with a camera

Hook

Upper lid
Hook

CameraLower lid

Lifting the upper and lower lids

Lowering and positioning the upper and lower lids
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.43

1) Development of an air-tight mechanism for large transfer containers[Test 2: Comprehensive function test (Method of verifying misalignment)]⚫
⚫
⚫

In order to verify the impact of misalignment on air-tightness at the time of remote assembly, the extent of misalignment
during work is measured in the element test.
Using a laser transmitter (laser marker), the extent of deviation between the reference line on the light-receptive plate
installed on the movable flange and the laser beam from the upper lid is measured, and the misalignment at each center
position is calculated.
Based on the results of the element test, the air-tightness when there is misalignment is verified, and is reflected in the studyof the method of installing the actual dual lid and the measurement method.

Light receptive
plate

Lifting beam

Light receptive plate

Lasertransmitter

Laser transmitter
Container flange lifting lug

Movable flange lifting lug

The levelness of theupper lid is adjusted
beforehand

Lower lid

Container flange

Overview of the element test apparatus

Illustration of
measuring misalignment (front view (cross section))

Illustration of measuring misalignment (floor plan)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.441) Development of an air-tight mechanism for large transfer containers[Test 2: Comprehensive function test (conducted 2 times for each part)]
Test
No.

Test details

Criteria for
determining
leakage rate
[L/h]With the upper and lower lids positioned, pressure is applied from Part
D and the pressure of Part D is verified.
(The integrity of sealed parts [3] to [5] in Part D is confirmed, and if
there is leakage, the sealed part from where there is leakage isdetermined.)

12

TargetRemarks

Air-tightness performanceverification test
2-2

Part D (Between the upper lid,
lower lid and movable flange)
Part A (Between the upper andlower lid)
Part B (Between the lower lid andcontainer)

Sealed part [3]Sealed part [5]Sealed part [6]Test flow of Test No. 2-2
Application of pressure
to Part D(400PaG, for 15
minutes)Is there any
leakage?

Part D(400PaG pressure is applied)
LeakageabsentEnd of testing(Sealed part [3], [5]and [6] are sound)

Sealed part [3]Leakage present
Application ofpressure to Part A(400PaG)

Leakage present
Leakage present insealed part [5]Sealed part [5]Application ofpressure to Part B(400PaG)
Leakage present insealed part [3]Leakage present
Is there any
leakage?

LeakageabsentLeakageabsentSealed part [6]Is there any
leakage?

Leakage present

Sealed part [4](Not to be tested)

Test container
Leakage present insealed part [6]Enlarged view of sealed part©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.45

1) Development of an air-tight mechanism for large transfer containers[Test 3: Offset test (conducted 3 times for each part)]
Test
No.

TargetCriteria for determining leakage
rate [L/h]3-1

The upper and lower lids and the movable flange are offset 50[mm] in the circumferential direction, and a test similar to Test 2 is conducted.

Test details

Remarks

・ The extent of misalignment was established based on the extent of deviation between the center of the upper lid and the center of the movable flange, wherein the upper lid can be installed inside
the movable flange.
・ The structure of the upper lid is such that it can be installed along the tapering shape of the fixed flange even if it is misaligned, but it is checked whether this has an impact on the air-tightness
assuming that it can move horizontally within the clearance between the upper lid and the movable flange.

135°
Container flange lifting lug

Upper and lower lid ismisaligned 50 [mm] at 45°

Part D(400[PaG] pressure is applied)

225°

45°

Sealed part [3]Sealed part [5]Upper lid

Lower lid315°

Sealed part [4](Not to be tested)

Sealed part [6]Movable flange

Test container

Lid

Lower lid
Container flange

Lifting the upper and lower lids

Upper and lower
lid is misaligned
50 [mm] at 45°

Enlarged view of sealed part

Lowering and positioning the upper and lower lids (when misaligned 50 [mm])©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.46

1) Development of an air-tight mechanism for large transfer containers[Test equipment configuration]
The test equipment configuration for the element testsof the large transfer containers is indicated below.

Enlarged view of the hook
Hook
(4 locations）

Hook

Upper lid (hook side)

Upper lid (top surface)Lug(4 locations)

Overview of the element test apparatus

Approx. 2[m]Movable flange

Lower lid

Lower lid (hook fitting part)Approx. 1.1[m]Upper andlower lid

Approx. 5[m]Lifting beam

Hook

Lug
Container body
(Only the diameter is simulated)

Full view of the element test
apparatus

Movable flange + container

Enlarged view of the hookfitting part©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.47

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 1 Air-tightness performance verification test of each part (conducted once for each part)]

The test method and results are indicated below.
No.1
verification items

Lower lid + container flange sealing performance1

Levelness verification of the container and flange set: 6 [mm] inclination
between both outer diameters

2O-ring [6] set

3

Lower lid set

4

Leakage check using water, for 15 minutes at 400[PaG]

No. 2
items

Rough drawing
Leakage check bypouring water

O-ringAir pressure 400Pa
Container flange

Upper lid + lower lid sealing performance verification

1

O-ring [4], [5], [6] set

2Upper lid set

3

Balance removal

4

Leakage check using water, for 15 minutes at 400[PaG]

Rough drawing
Leakage checkby pouring
water

Removal of upper and lower lid

2

Movable flange set, levelness measurement: Movable flange sheet
surface3Upper lid set

4

Leakage check using water, for 15 minutes at 400[PaG]

5

Removal of upper lid

6

Cleaning of each component and site

Air pressure
400Pa

Upper lid

Lower lid

O-ringNo. 3
Upper lid+ movable flange, movable flange + container
sealing performance verification items
1

Lower lid

Container flange

Rough drawing

Leakage checkby pouringwater

O-ringMovable flange
Upper lid

Air pressure 400Pa

Air pressure 400Pa

Since air bubbles were not generated in any of the tests, a comprehensive function test was conducted.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.48

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 1 Air-tightness performance verification test of each part (conducted once for each part)]

Photos taken during the test are given below.

Lower lid

No.1 Lower lid + container flange sealing performance verification work

Water

Part A
Leakagecheck bypouring water

Lower lid

Container
flangeO-ringAir pressure 400Pa
Container flange

Enlarged view of Part A
No. 2 Upper lid + lower lid sealing performance verification work
Leakagecheck bypouring water

Upper lid

Air pressure 400Pa

Container flange

Upper andlower lid

Water

Lower lid

Part B
O-ringMovable flange

Container flange

No. 3 Upper lid + movable flange, movable flange +container sealing performance verification work

Leakagecheck bypouring water

Enlarged view of Part B

Water

Movable flange
Upper lid

Movable flange

Upper lid

Air pressure 400Pa

Part C
Container flangePart D
O-ringContainer flange

Enlarged view of Part C

Enlarged view of Part D©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.49

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 2 Comprehensive function test]
The test steps are given below.

Upper lid[2] Upper and lower lid fitting preparation[3] Upper and lower lid fitting completion[4] Upper and lower lid movement

Lower lid

[1] Upper lid lifting[5] Upper and lower lid movement completion[7] Upper and lower lid lowering completion[6] Upper and lower lid lowering

Light receptive
plate

Hook
surveillancemonitorLasertransmitter

Pressure gauge
and other
instruments

Nitrogencylinder[8] Dimension measurement work

[9] Air-tightness test
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.50

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 2 Comprehensive function test
Test No. 2-1: Positioning, fitting test (conducted 3 times for each part)]
Fitting and attachment/detachment of the upper and lower lids was accomplished smoothly without any noise, damage,etc. in all 3 instances.
Dimension measurement results are provided on the next page.
Round
No.

Extent of misalignment[mm] *1

1

1.9

2

1.3

3

4.6

Target value [mm]

Hook

5.0±5

Movable flange, inner surface of container Sides of the upper and lower lid(After the test)(After the test)
Visual image taken by the monitoring camera(Condition when lower lid does not fit)

*1: Extent of misalignment of center of the movable
flange and the center of the upper and lower lids

Hook
Verifying the disengagement of thehook with a camera

Verifying the engagement of thehook with a camera

Hook

Upper lid
Hook
MovableflangeUpper lid
Lower lid

CameraLower lid

Container flange
Container flange

Lifting of the upper and lower lids

Lowering and positioning the upper and lower lids

Visual image taken by the monitoring camera(State of hook fitting)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.51

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 2 Comprehensive function test
Test No. 2-1: Positioning, fitting test (conducted 3 times for each part)]
Dimension measurement results are provided below.

*1: + indicates clockwise, - indicates anti-clockwise

1st round

2nd round

3rd round

Item
Beforepositioning
the upper
and lower
lids

After
positioning
the upper
and lower
lids

45°

135°

225°

315°

45°

135°

225°

315°

45°

135°

225°

315°

1.5

-1.0

-1.0

-1.5

1.5

0.5

1.0

0.5

-4.0

-3.0

4.0

1.0

(1) Extent of misalignment [mm](Target value: within 5± 5[mm])*1

Extent of misalignment: 1.9(2) Extent of misalignment in thehorizontal direction [mm](Inner surface of the movable flange- side of the upper lid)

12.0(3) Vertical dimensions [mm](Upper surface of the movable
flange - upper surface of the upper
lid)

224.0

135°

9.5

10.2

Extent of misalignment: 1.3

13.0

12.0

Laser transmitter
(2)

224.0

224.5

224.0

224.0

12.5

8.5

15.0

14.0

7.5

Upper lid

Test container Lower lid

Measurement locations

224.5

224.5

224.0

224.0

225.0

224.0

224.5

nom.225(Dimensions when the O-ring is flattened to the prescribed extent and the surfaces of the seals touch each other)

225°

315°

10.0

Nom.10(Dimensions when the center of the movable flange and center of the upper lid are aligned)

Light receptive
plate
45°

10.0

Extent of misalignment: 4.6(3)

・ From the results of measuring the verticaldimensions (upper surface of the movable
flange and upper surface of the upper lid), it isassumed that the prescribed flattening of the Oring has been secured.
・ Also, from the air-tightness test results givenon the next page as well, it appears that theprescribed flattening of the O-ring has been
secured and air-tightness has been achieved.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.52

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 2 Comprehensive function test
Test No. 2-2: Air-tightness performance verification test (conducted 3 times for each part)]
The test results are indicated below.
It was verified that the leakage rate in Part D is equal to or lower than the criteria, in all 3 instances. Detailed test results are indicatedon the next page.
Number ofroundsCriteria for determining
leakage rate [L/h]Part D leakage rate[L/h]1

The + in the leakage rate indicates inflow, and - indicates leakage.
(・Since the pressure in Part A, Part B and the atmosphere that are adjacent
to Part D, is low as against Part D (400[PaG]), there is no inflow.
・Since leakage is almost 0, external factors (fluctuations in the atmosphericpressure, changes in temperature) could have a minor impact and lead toinflow, but it is 0.19/12*100=approx. 2% as against the leakage rate criteria,
which is a sufficiently small value even if there were inflow.)

+0.04

2

12

+0.19

3

Remarks+0.16

Test flow of test No. 2-2
Pressurization ofPart D (400PaG, for
15 minutes)

Is there any
leakage?

Sealed part [3]Leakageabsent End of test (Sealed
parts (3), (5) and(6) are sound)

Sealed part [5]Leakage present
Pressurization ofPart A (400PaG)

There is leakage
in sealed part (5)Leakagepresent

Leakage present
LeakageabsentIs there any
leakage?

Sealed part [6]Pressurization ofPart B (400Pag)
There is leakage
in sealed part (3)Part D(400[PaG] pressure
is applied)

LeakageabsentIs there any
leakage?

Test container
Leakage present

There is leakage
in sealed part (6)Enlarged view of sealed part©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project
1)

No.53

Development of an air-tight mechanism for large transfer containers

1st
round

Item

[Test results: Test 2 Fitting function test
Test No. 2-2: Air-tightness performance verification test (conducted 3 times for each part)]

2st
round

3st
round

P1[Pa]

431.59412.66409.16

P2[Pa]

436.62404.84428.62

T1[℃]

8.1

8.2

8.7

T2[℃]

8.1

8.1

8.6

Patm1[Pa]101674101715101952

Patm2[Pa]101678101733101935

Testing time
period⊿t[min]

15.00

15.00

15.00

Leakage rateq[L/h]

0.04

0.19

0.16

1st round15

400
Testing time period (15 minutes)

Pressure [PaG]

300

10

200
100
0
14:02

Pressure in
D部圧力Pa
Part D Pa

14:09

14:16

14:31

Part D ℃

14:38

14:45

5

Atmospheric pressure

15

400
300

Testing time period (15 minutes)

10

200
100
0
15:57

Temperature in
D部温度 ﾟC
Part D ℃

Pressure
D部圧力inPa
Part D Pa

16:04

16:12

16:19

16:26

16:33

16:40

Time

15

400
Testing time period (15 minutes)

10

200
100
0
12:57

Pressure in
D部圧力
Part
D PaPa

13:04

13:12

13:19

13:26

Temperature in
D部温度
Part
D ℃ﾟC

13:33

Temperature [℃]

Pressure [PaG]

500

Q=

V𝑇20 𝑃2 𝑃1 V𝑇20 𝑃𝑎𝑡𝑚2 𝑃𝑎𝑡𝑚1−−[𝑃𝑎・ 𝐿Τ𝑠]
Δ𝑡 𝑇2 𝑇1 ＋ Δ𝑡
𝑇2
𝑇1

𝑞=

𝑄
[𝐿Τ𝑠]
1013255

3rd round300

Temperature inside
the test pieceTime

2nd round500
Pressure [PaG]

14:24

Temperature
D部温度
ﾟC in

Temperature [℃]500

Temperature [℃]

Pressure in Part D

5
13:40 Time

Here, the leakage rate (Pa・L/s) is in terms of Q: 20°C
P1: Gauge pressure (Pa) of the test specimen when measurement starts
P2: Gauge pressure (Pa) of the test specimen when measurement ends
Patm1: Atmospheric pressure (outside pressure) (Pa) when measurement starts
Patm2: Atmospheric pressure (outside pressure) (Pa) after measurement starts
Δt : Time from start of measurement to end of measurement (s)V: Internal volume (L) of the test specimen
T20: Reference temperature 293 (K)T1: Absolute temperature (K) of the gas inside the test specimen whenmeasurement starts
T2: Absolute temperature (K) of the gas inside the test specimen whenmeasurement ends
q: Leakage rate (L/s) in terms of 20℃ and 1 atmospheric pressure©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.54

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 3 Offset test (conducted 3 times for each part)]
The test results are indicated below. Detailed test results are indicated on the next page.
In the test in which the members were misaligned as well, it was verified that there wasno noise, damage, etc., the sides of the upper and lower lid entered following the innersurface of the movable flange and was certainly positioned.

[Results of measuring the extent of misalignment]

There were marks indicating
scraping of the anti-rust agent
coated on the surface.
(From the results of the airtightness test, this does not affectthe air-tightness performance)

135°

Laser transmitter

Sides of the upper and lower lid (after the test)
Container flange lifting lug

NumberofroundsExtent of
misalignment [mm]
*1

1

50.5

2

53.0

3

50.0

Target value
[mm]

50±5

*1: Extent of misalignment of centerof the movable flange and thecenter of the upper and lower lids

Light receptive
plate

225°

45°

Upper and lower
lid is misaligned
50 [mm] at 45°

Inner surface of the movable flange (after the test)
Nitrogen cylinder
400PaG pressure isapplied andmaintained

315°

Upper lidP
MovableflangeCameraContainer flange

Lifting the upper and lower lids

Lower lid

Pressure is measured
and leakage rate is
calculated

MovableflangeUpper and lower lid
is misaligned 50[mm] at 45°

Lowering and positioning the upper and lower lids (when misaligned 50 [mm])Container flange

Air-tightness performance verification test (when misaligned 50[mm])©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.55

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 3 Offset test (conducted 3 times for each part)]
Dimension measurement results are provided below.

*1: + indicates clockwise, - indicates anti-clockwise

1rd round

2rd round

3rd round

Item
Beforepositioning
the upper
and lower
lid

After
positioning
the upper
and lower
lid

135°

225°

315°

45°

135°

225°

315°

45°

135°

225°

315°

5

-45

4

54

11

-40

14

64

3.5

-45.5

3.5

52.5

(1) Extent of misalignment [mm](Target value: within 5± 5[mm])*1

Extent of misalignment: 50.5

(2) Extent of misalignment in thehorizontal direction [mm](Inner surface of the movable
flange - side of the upper lid)

0.7(3) Vertical dimensions [mm](Upper surface of the movable
flange - upper surface of theupper lid)

224.5

135°
Light receptive
plateUpper andlower lid ismisaligned 50[mm] at 45°

45°

45°

11.0

24.0

Extent of misalignment: 53.0

11.2

0.6

11.5

22.0

10.5

0.6

11.3

22.2

10.9

224.0

224.5

nom.10(Dimensions when the center of the movable flange and center of the upper lid are aligned)
224.5

224.0

224.0

224.5

224.5

224.0

224.0

224.0

224.5

nom.225(Dimensions when the O-ring is flattened to the prescribed extent and the surfaces of the seals touch each other)

Laser transmitter(2)

Upper lid

(3)

225°

Test container
315°

Extent of misalignment: 50.0

Lower lid・ Similar to Test 2, from the results ofmeasuring the vertical dimensions, itappears that flattening of the O-ring has
been secured.
・ Also, from the air-tightness test results
given on the next page as well, it appears
that the prescribed flattening of the O-ringhas been secured and air-tightness has
been achieved.

Measurement locations©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.56

1) Development of an air-tight mechanism for large transfer containers[Test results: Test 3 Offset test (conducted 3 times for each part)]
The test results are indicated below.
It was verified that the leakage rate in is equal to or lower than the criteria in all 3 instances. Detailed test results are indicatedon the next page.
Number ofroundsCriteria for determining
leakage rate [L/h]Part D leakage rate[L/h]1st round

The + in the leakage rate indicates inflow, and - indicates leakage.
(Since leakage is almost 0, external factors (fluctuations in theatmospheric pressure, changes in temperature) could have a minor
impact and lead to inflow, but it is 0.15/12*100=approx. 2% asagainst the leakage rate criteria, which is a sufficiently small valueeven if there were inflow.)+0.15

2nd round

12

+0.01

3rd round

Remarks

0.00

Pressurization ofPart D (400PaG, for
15 minutes)

Is there any
leakage?

Sealed part [3]Leakageabsent End of test (Sealed
parts (3), (5) and(6) are sound)

Sealed part [5]Leakage present
Pressurization ofPart A (400PaG)

Sealed part [6]Pressurization ofPart B (400Pag)
There is leakage insealed part (3)Leakage present
There is leakage insealed part (5)Leakagepresent
Is there any
leakage?

LeakageabsentPart D(400[PaG] pressure
is applied)

LeakageabsentIs there any
leakage?

Leakage present

Test container

There is leakage insealed part (6)Enlarged view of sealed part©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.57

1) Development of an air-tight mechanism for large transfer containers

1st
round

Item

2nd
round

3rd
round

[Test results: Test 3 Offset test (conducted 3 times for each part)]

15
13

Testing time period (15 minutes)

300

11

200

9

0
12:43

Pressure in
D部圧力Pa
Part D Pa

12:50

12:57

13:04

Temperature
D部温度 ﾟC in
Part D ℃

13:12

13:19

13:26 Time

7
5

Temperature [℃]

Pressure [PaG]

500

100

446.16423.91422.75

P2[Pa]

464.75453.41452.00

T1[℃]

9.1

9.7

8.6

T2[℃]

9.0

9.7

8.6

Patm1[Pa]101898101759102051

Patm2[Pa]101880101731102022

Testing time
period⊿t[min]

15

15

15

Leakage rateq[L/h]

0.15

0.01

0.00

Pressure in Part D

1st round400

P1[Pa]

Test piece gas
temperature

Atmosphericpressure

15

400

13

Testing time period (15 minutes)

300

11

200

9

100
0
12:43

12:50

12:57

13:12

13:19

13:26

Time

3rd round500

Pressure [PaG]

13:04

7

Temperature in
D部温度
Part
D ℃ ﾟC

Pressure in
D部圧力
Part
D Pa Pa

15

400

13
Testing time period (15 minutes)

300
200

11
9

100
0
11:16

5

Pressure in
D部圧力
Part
D Pa Pa

11:24

11:31

11:38

11:45

Temperature in
D部温度
Part
D ℃ ﾟC

11:52

7

5
12:00

Temperature [℃]500

Temperature [℃]

Pressure [PaG]

2nd round

Time

Q=

V𝑇20 𝑃2 𝑃1 V𝑇20 𝑃𝑎𝑡𝑚2 𝑃𝑎𝑡𝑚1−−[𝑃𝑎・ 𝐿Τ𝑠]
Δ𝑡 𝑇2 𝑇1 ＋ Δ𝑡
𝑇2
𝑇1

𝑞=

𝑄
[𝐿Τ𝑠]
101325Here, the leakage rate (Pa・L/s) is in terms of Q: 20°C
P1: Gauge pressure (Pa) of the test specimen when measurement starts
P2: Gauge pressure (Pa) of the test specimen when measurement ends
Patm1: Atmospheric pressure (outside pressure) (Pa) when measurement starts
Patm2: Atmospheric pressure (outside pressure) (Pa) after measurement starts
Δt : Time from start of measurement to end of measurement (s)V: Internal volume (L) of the test specimen
T20: Reference temperature 293 (K)T1: Absolute temperature (K) of the gas inside the test specimen whenmeasurement starts
T2: Absolute temperature (K) of the gas inside the test specimen whenmeasurement ends
q: Leakage rate (L/s) in terms of 20℃ and 1 atmospheric pressure©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.58

1) Development of an air-tight mechanism for large transfer containers[Extent to which the O-ring is flattened]
The extent of flattening of the O-ring was evaluated based on the production drawing of the dual lid and the dimensions
measured at the time of the test.
Extent of flatteningof the O-ring at thetime of (1)Requiredextent offlattening of Oring

Dimensions from the uppersurface of the upper lid to theupper surface of the movable
flange at the time of (1)Sealed part(1) Manufacturing tolerance ofeach site when the O-ring
flattening is at its minimum

Sealed part [3]Container, movable flange Lower lid +Upper lid +

4.5mm
(*1)

220

Sealed part [5]Container, movable flange +Lower lid Upper lid -

4.5mm
(*2)

230

Sealed part [6]－(At the stage when the hook of
the upper lid is removed, thesurface of the lower lid and thecontainer flange come incontact.)

－

150±1

Sealed part [5]Sealed part [6]Dual lid dimensions

225

224.0 to 225.0

Even under the mechanical tolerance (it was confirmed that all dimensions verified after
fabrication were within the tolerance) of each section when the extent of flattening of the Oring is at its minimum, the required extent of flattening of the O-ring is met.
Moreover, from the measurements obtained during the test as well, it was verified that therequired extent of flattening of the O-ring is met.

4. 5
(Extent of flattening)

3.5
(Gap)

(300
)
200±0.5 300±0.1
150±1

200±1

825

Lower lid, upper lid dimensions

Sealed part [3]Measurements
obtained from this
test

－

225

Movable flange,
Container flange dimensions

8mm to 2.4mm

Nominal dimensions
from the upper surfaceof the upper lid to theupper surface of the
movable flange

Extent of flattening of the O-ring*1
Gap: ((150+1)+(200+0.5))-((150-1)+(200-1)) = 3.5[mm]Extent of flattening of the O-ring: 8-3.5＝4.5[mm]Dimensions from the upper surface of the upper lid to the uppersurface of the movable flange：(150-1+200-1+825)-(150+1+500+1+300+1)) =220[mm]*2Gap: ((150+1)+(200+1)) - ((150-1)+(200-0.5)) = 3.5[mm]Extent of flattening of the O-ring: 8-3.5＝4.5[mm]Dimensions from the upper surface of the upper lid to the upper surfaceof the movable flange：(150+1+200+1+825)-(150-1+500-1+300-1)) =230[mm]©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.59

1) Development of an air-tight mechanism for large transfer containers[Organization of test results]
The results of the verification items included in the test plan are indicated below.
ID:

Items

Details

Items to be monitored,measured and recorded

Criteria

Test results

Validity of the lid
opening/closing
mechanism⚫ Verification of the movement of the lid
opening/closing mechanism by operating the hook
⚫ Verification of the connection between the upper
lid and lower lid when the lower lid is installed andthe upper lid is lifted up by means of the hook, andverification of the gap, etc.

➢ Abnormal noise, rattling, etc.
➢ Connecting portion between
the upper and lower lid➢ Gap (Extent to which the Oring is flattened)➢ Moves normally.
➢ As per the dimensions.
➢ Meets the O-ring specifications
and is within the design range➢ It was confirmed that the mechanism
can operate normally without any
noise, damage, etc.
➢ It was confirmed that the dimensions
between the upper lid and lower lid
are as per the design.
➢ It was confirmed that the extent offlattening of the O-ring is under theprescribed value.

Verification of theconnection
checking method⚫ Verification of the connections between the upper
lid and lower lid, the lower lid and container body,and the upper lid and movable flange➢ Verification of dimensions(Extent of flattening of the Oring is estimated from themeasurement of dimensions)➢ Measured dimensions arewithin the design range.

➢ It was confirmed that the extent offlattening of the O-ring is under theprescribed value.

3

Air-tightness
performance⚫ Verification of the air-tightness at each step
⚫ Verification of air-tightness in case the part to beconnected to is misaligned(It were verified that air-tightness is maintainedeven if there is misalignment, and this wasreflected in the study of accuracy specifications
for container position alignment in the expandedbuilding.)⚫ The sealed part [3]: between movable flange andupper lid, sealed part [5]: between upper lid andlower lid and sealed part [6]: between lower lid andcontainer were verified.

➢ Gap (Extent to which the Oring is flattened)➢ Pressure➢ Meets the O-ring specifications
and is within the design range➢ Leakage rate: 0.1 [vol%/h] or
less

4

Confirmation of
reproducibility⚫ Tests were conducted multiple times to verify
reproducibility of the items to be monitored.

Same as items 1 to 3 aboveー➢ The air-tightness test was conducted
3 times and reproducibility wasconfirmed.

Criteria for
determining
whether thecontainer can beseparated⚫ It was remotely verified that the upper and lower
lids are installed and the hook gets disengaged as
the lifting beam gets lowered.

➢ The hook comes off from thelug of the lower lid.

➢ It was confirmed that the hook can be
engaged and disengaged.

1

2

5

➢ Position of the hook

➢ It was confirmed that the extent offlattening of the O-ring is under theprescribed value.
➢ It was confirmed that the leakage rateis equal to or lower than the criteria
regardless of misalignment.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.60

1) Development of an air-tight mechanism for large transfer containers[Issues]
Future issues that occurred during the tests are indicated below.
● A phenomenon of O-ring removal
After the test, when the upper and lower lid were removed, the O-ring came off from the U groove in which it was inserted. It is presumed
that this happened because the O-ring adhered to the metal surface and because of the impact of condensation.
In the actual equipment, the U groove for the O-ring will be changed to a dovetail groove as a measure to prevent the O-ring from coming off.
In the case of a dovetail groove, since damage is likely to occur at the time of installing the O-ring by means of remote operation, or pressing
cracks, etc. are likely to occur due to surface pressure, applicability of the dovetail groove to actual equipment will be studied in the future.
O-ring groove

O-ring groove

O-ringO-ring thathas loosen.

O-ring thathas loosen.

O-ring for the lower lid(Sealed part [5] U groove)

O-ring for the movable flange(Sealed part [3] U groove)

Movable flange

O-ring for the container(Sealed part [6] dovetail groove)
Surface pressure

Surface pressure

Surface pressure

Upper lid

O-ring for the lower lid（Sealed part [3] Ugroove）

Surfacepressure

Condensation
Surface pressure

O-ring for the movable
flange（Sealed part [5] Ugroove）

Lower lid

O-ring for the container(Sealed part [6] dovetailgroove)・ Since the filling factor is greater compared to the U groove, pressing cracks tend to occur easily.
・ It is presumed that the O-ring gets complexly deformed due to surface pressure from 4
directions.
(Surface pressure from 2 directions in the case of U groove)
These impacts were evaluated and it was verified that pressing cracks, etc are not likely to occur
in the O-ring.

Test container
Enlarged view of sealed part

Surface pressure

Side of the movable flange, container

Applicability of dovetail groove to actual equipment©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.61

1) Development of an air-tight mechanism for large transfer containers[Future challenges]
The future challenges pertaining to large transfer containers in general are indicated.
ID:

Item

Details of the problems

Future course of action

1

Method of carrying-in the container

Method of carrying-in considering positioning and fall prevention measures

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

2

Method of determining the container location

Method of positioning the movable flange and container considering the results of the tests
conducted this time

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

3

Method of inspection prior to container transportation

Method of inspection prior to transportation from the expanded building to the newly constructedbuilding

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

4

Method of lifting and lowering the movable flange

Method of lifting and lowering the movable flange

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

5

Structure of the lid for transportation

Structure of the lid for transportation (including method of inspection at the time of accident, prior
to transportation, etc.)

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

6

Structure of the connecting part between the movable flange andexpanded building

Connection of the movable flange and water seal

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

7

Method of decontaminating the inside of the container

Decontamination method and structure for repeated use

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

8

Impact of the shape of the groove for O-ring on sealing
performance

Study on the stress acting on the O-ring when a dovetail groove is used

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

9

Method of maintaining the sealed parts

Method of replacement by means of remote operation

Study will be continued under the Project forDevelopment of Fuel Debris Retrieval Method

10

Specifications of the structures and debris to be collected

Radiation dose, amount of radioactivity, concentration of contamination, shape, properties

Part of the study will be conducted under the Project forDevelopment of Fuel Debris Retrieval Method

11

Study related to safety (hydrogen, earthquake, etc.)

Identification of events that could occur when the container is being used, and measures in
response to those events

Study will be conducted in cooperation with otherprojects

12

Manufacturability of the main body of the container

Manufacturability concerning large structures will be verified

Verified during the Project for Development of Fuel
Debris Retrieval Method

13

Specifications and location of the expanded building

Specifications of the connection part of the large transfer containers, maintenance area, airconditioning, etc., and the location where the expanded building will be constructed

Study will be conducted in cooperation with otherprojects

14

Specifications and location of the newly constructed building

Specifications of the connection part of the large transfer containers, maintenance area, airconditioning, etc., and the location where the newly constructed building will be constructed

Study will be conducted in cooperation with otherprojects

15

Pavement of the transportation route between the expandedbuilding and the newly constructed building

Pavement will be studied after determining the transportation method and the locations where theexpanded building and newly constructed building will be constructed

Study will be conducted in cooperation with otherprojects©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.62

1) Development of an air-tight mechanism for large transfer containers[Study on criticality control methods]
Solidifying the structures to which fuel debris is adhered using a solidification agent containing neutron absorption material is being
studied, and in that case, at the point in time when the structures are collected in the container, they are sub-critical. It is assumed
that there is almost no concern of criticality, but proposals on measures are studied just in case, assuming that an amount of fueldebris more than the critical mass moves away from the solidified objects and mixes with free water.
ID:

Matters of concern

1

Separation of fuel debris due tofalling at the time of collecting thestructures in large transfer containers

2

3

4

Re-criticality due to separation of fueldebris after it is collected incontainers, and formation of freewater

Proposed countermeasures

Remarks

・Preventing falling of fuel debris by using multiple cranes.

・Solidifying (additionally) by pouring filler material after collecting debris in the containers.
・Injecting neutron absorption material.
→ [1] Injection of boric acid solution
・Store boric acid solution in a container beforehand. Or, pour boric acid solution after the structures are collected.
[2] Injection of non-soluble neutron absorption material
・Keep glass material containing B and Gd in a container beforehand.

Effect on criticality due to vibrations
or impact during transportation or due
to falling of the container. (Change inthe shape of structures, etc.)

・Injecting neutron absorption material, etc. (handled in a similar manner as described above)

Method of detecting criticality duringtransportation

・Criticality does not need to be assumed as sub-critical large structures are solidified with the help of asolidification agent containing non-soluble neutron absorption material, and fuel debris fall prevention
measures are implemented as well.
・Using the neutron monitor for detecting criticality as well as for controlling the radiation dose in the vicinity ofthe transport cask.

The criticality prevention measure of injecting non-soluble neutron absorption material (glass material containing B and Gd) into
the large transfer containers was studied and the required quantity was evaluated.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.63

1) Development of an air-tight mechanism for large transfer containers[Assumptions of criticality evaluation]⚫

Lid
Fuel debris
RPV bottom head

Solidification agent containing
neutron absorption material

Large transfer
container main body⚫

CRD housing
Structure fixing frame⚫
UO2 and free water fallfrom the solidification
agent containing neutron
absorption material⚫

As shown in the figure on the left, the fuel debris solidified using
solidification agent containing neutron absorption material, theRPV bottom head, and the CRD housing, etc. are assumed tobe supported by the structure fixing frame inside the largetransfer container.
It is assumed that for some reason UO2 (enrichment 4.9[wt%])
and free water fall from the solidification agent containing
neutron absorption material on to the lower part of the largetransfer container. Also, it is assumed that the solidification
agent containing neutron absorption material does not fall.
It is assumed that the fallen UO2 is approx. 100[㎏]*1 and thedepth*2 of the free water fallen on to the lower part of the largetransfer container is about 45[cm].
It is assumed that approx. 100[kg]UO2 in free water results in
optimum deceleration.

Based on the above-mentioned conditions the required quantity of
non-soluble neutron absorption material poured in advance on to thelarge transfer container was evaluated.
UO2
Free water
Illustration of collection into largetransfer containers[Notes]*1: It is assumed that approx. 1% of the maximum value of approx. 6 [ton] of fuel debris adhered to
the RPV bottom part CRD housing in the “Subsidy Project for the Decommissioning andContaminated Water Countermeasures in the FY2014 Supplementary Budget (Advancement ofunderstanding of the in-core conditions through accident progression analysis and actual equipment
data, etc.)”, falls and gets pulverized.
*2: It is assumed that water accumulates all over the reactor bottom (RPV bottom head) and all thatwater flows to the bottom of the container.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.64

1) Development of an air-tight mechanism for large transfer containers

28

Φ600
Fuel
deb

680

Φ750

28

[Results of criticality evaluation]

28

Scope
risof
model creation

・ Computer program used
SCALE6 Code System
・ Criteriakeff（calculated value)+3σ ≦ 0.95
・ Non-soluble neutron absorption
material to be evaluatedGlass material containing B and Gd

30

Schematic view of the large transfer
container (XZ direction) (Unit: cm)
Region withfree water

108

Region with
nuclear material

30（UO2, free water, B and Gd）

3
0

48

30

108
XY direction (Unit: cm)

Forged carbon steel

XZ direction (Unit: cm)

Computational model

45

108
48

（UO2, free water, B and Gd）

48
30
Region with free water

28

30
Region with
nuclear material⚫ In this evaluation, it was assumed that the approx.
100[kg] of fallen Uo2 is clustered together (region with
nuclear material) in the area where there is optimum
deceleration in free water, and considering the heightof glass material containing B and Gd in this region
with nuclear material as a parameter, the required
quantity was surveyed.
⚫ If the conditions for optimum deceleration of the
100[kg] of fallen Uo2, are assumed, the size of theregion with nuclear material is approx. 1/10 of theinner diameter of the large transfer container.
Considering that there is 30[cm] of free water in thesurrounding, the structural material in the XY direction
was conservatively omitted. Similarly, among thestructural material in the XZ direction, the lid of thelarge transfer container was conservatively omitted.
⚫ It was conservatively assumed that the glass material
containing B and Gd is present only inside the region
with nuclear material, and does not exist in free water.
However, the required weight was calculated based on
the area of the base of the large transfer container
considering the uncertainty of the extent to which
nuclear material is spread inside the large transfer
container.

As a result of criticality evaluation, the height of the glass material containing B and Gd is 20[cm] from the base of the large transfer
container, keff（calculated value）+3σ is lower than 0.95 and the required quantity of glass material containing B and Gd at this time is approx.
14 [ton].
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.65

1) Development of an air-tight mechanism for large transfer containers[Results of criticality evaluation]
The drawing illustrating the status when the reactor bottom is transferred considering theresults of criticality evaluation is shown below.
Fuel debris

Lid⚫ Non-soluble neutron absorption material is spread at
the bottom of the large transfer container in advance.

Solidification agent
containing neutron
absorption material⚫ Height of the non-soluble neutron absorption material:
20[cm]・ Height of the large transfer container：680[cm]

RPV bottom head680

CRD housing

Large transfer container mainbody
Non-soluble neutron
absorption material
Glass material containing
B and Gd

Φ600

20

Structure fixing
frame⚫ Weight of the non-soluble neutron absorption material:
Approx. 14[ton]・ Weight of the reactor bottom part that is filled andsolidified： 249[ton]・ Weight of the large transfer container (including thelid)：520[ton]Schematic drawing of the large transfer container (XZ direction) (Unit: cm) at thetime of transferring the reactor bottom considering the results of evaluation
Even if results of criticality evaluation under conservative conditions are considered, the height or weight of the non-soluble neutron
absorption material injected is approximately 3% of the entire large transfer container (when transferring the reactor bottom).
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.66

1) Development of an air-tight mechanism for large transfer containers: Summary➢ The air-tight mechanism of the lid part of large transfer containers required for transferringlarge structures, which have a function for preventing the spread of contamination and ashielding function against high radiation items stored in them, was studied. Steps involved ininstalling the dual lid for transferring structures were examined, and issues of applying thedual lid were identified.
➢ Items to be verified through element tests were identified from the issues when installing thedual lid, and element tests on the validity of the opening/closing mechanism of the dual lid andthe air-tightness performance were conducted. It was verified through element tests that thedual lid mechanism can work normally, and that the leakage rate meets the established leakage
rate standard of 0.1 [vol%/ｈ] or less. Thus the feasibility was verified.
➢ Based on the above-mentioned test results, future challenges such as method of positioning
and inspecting the container, impact of the shape of the groove for O-ring on sealing
performance, sealed part maintenance method, etc., were clarified
Studies will be continued under the Project for Development of Fuel Debris Retrieval Method.
➢ To ensure the safety of criticality of the large containers used for collecting the unitized large
structures to which fuel debris is adhered, methods for preventing re-criticality and detecting
criticality approach were conducted. The criticality prevention measure of injecting nonsoluble neutron absorption material into the large transfer container in advance was studied
and the required amount of non-soluble neutron absorption material under conservative
conditions was evaluated.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.67

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts
Development items involving solicitation

Implementation policy (proposed)

Remarks

1) Development of an air-tight mechanism for largetransfer containers

With respect to retrieving fuel debris and reactor internals, the method of transferring the unitized large structures is being
studied in order to improve the throughput for the top access as part of the development being undertaken since FY2019. In
order to transfer large structures, it is necessary to develop large transfer containers with a function for preventing the spreadof contamination and shielding function for high radiation items stored in containers.
Upon studying the pre-conditions for the large transfer containers and the required development items, an air-tightmechanism for the lid of the large transfer container will be developed. And, the criticality control method for the period fromafter collection of the structures until they are stored, will be studied.

2) Development of technology for connecting heavy
structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for accessAs the new access equipment (access tunnel, cell, etc.) to be installed in the R/B is heavy equipment weighing several
hundred tons, technology for connecting the heavy structures to the PCV by means of remote operation will be developed.

Items to be explained[2] Confinement structure for the connection parts
As the equipment to be newly installed needs to be equipped with the function of absorbing displacements in the event of anearthquake in addition to a confinement function for the connection parts, a displacement absorption structure for the PCV
connection parts will be developed.

Displacement
変位吸収機構absorption mechanism

425 tonSleeveスリーブ

Slide part
Load supporting
point

Welding
溶接
PCV(equipment hatch)
PCV(機器ハッチ)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.682) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts
With regards to the new access equipment (access tunnel, cell, etc.) to be installed in the R/B, the development
challenges concerning the structure, construction method, inspection, maintenance, etc. will be studied andorganized as part of the technological development for ensuring confinement function in the parts connected to theexisting structures such as PCV, etc., the required element tests including the following will be conducted, and theviability of the technology will be verified.
[1] Technology for connecting heavy structures used for accessIn order to install the new access equipment on the PCV connection part (equipment hatch, etc.), the work ofmoving the heavy structures weighing several hundred tons into the R/B and accurately adjusting its positions with
the PCV connection part needs to be carried out while reducing exposure during work and while ensuring worksafety.
Hence, technology (position adjustment and installation) for connecting heavy structures needs to be developed,
which would make it possible to carry out installation while taking into consideration various factors such as notexceeding the R/B floor load limit, moving, turning and position adjustment of heavy structures while avoiding
existing structures and equipment in the R/B, and carrying out remote operations so that workers do not have toenter the site as far as possible since the radiation levels inside the R/B are high.
Technical studies of bridges, plants, etc. will be included in the examination and applicable technology forconnecting heavy structures will be developed.
And, mock-up element tests will be conducted by simulating the actual weight of the equipment to verify on-site
applicability.
[2] Confinement structure for the connection parts
The new access equipment to be connected to the PCV needs to be equipped with the function of absorbing
displacements in the event of an earthquake in addition to a confinement function for the connection parts.
The displacement absorption structure of the PCV connection parts for the heavy structures to be installed in R/Bwill be developed considering the options of combining or improving on existing technologies and the feasibility
will be evaluated by conducting element tests.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.69

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts
Project of Technological Development of Upgrading of Method and Systems(implemented in FY2017-2018)[Verification of the feasibility of the method (conducting shape, dimensions,scale related element tests)]➢
Delivery of the tunnel path➢
Delivery of the curved surface tunnel through the narrow opening➢
Remote work monitoring, positioning accuracy

Opening of biological shield

Access tunnel

Delivery
Project of Development of Technology for Further Increasing theRetrieval Scale of Fuel Debris (implemented in FY2019- 2020)[Verification of the connection method]➢
Study of issues identified above➢
Method of connecting with the BSW (sleeve welding test)➢
Study of sleeve (displacement absorption mechanism)
structure

SleeveDisplacement
absorption mechanism

Sleeve➢Study of the method of remotely installing and welding thesleeve, etc.

SleeveApprox.
1800mm425 [ton]
PCV(Equipment hatch)
Slide part

Items studied under the Project for Development of Fuel Debris
Retrieval Method

Location of R/B
outer wall

Displacement absorption
mechanism

Load supporting
point

Implemented in this project[Verification of feasibility through testing]➢
Heavy object delivery (verification of the slide
part)➢
Displacement absorption mechanism (Leakage
rate verification)

Access tunnel

Access tunnel(actual outer appearance)

Loadsupporting
point

Welding
The main body of the sleeve isbeing studied under the
Project for Development ofFuel Debris Retrieval Method©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.702) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for access
Development items involving solicitation

Implementation policy (proposed)

Remarks

1) Development of an air-tight mechanism forlarge transfer containers

With respect to retrieving fuel debris and reactor internals, the method of transferring the unitized large
structures is being studied in order to improve the throughput for the top access as part of the development
being undertaken since FY2019. In order to transfer large structures, it is necessary to develop large transfer
containers with a function for preventing the spread of contamination and shielding function for high radiation
items stored in containers.
Upon studying the pre-conditions for the large transfer containers and the required development items, an airtight mechanism for the lid of the large transfer container will be developed. And, the criticality control method
for the period from after collection of the structures until they are stored, will be studied.

2) Development of technology for connecting
heavy structures for accessing PCV
and the confinement structure for theconnection parts[1] Technology for connecting heavy structures used for accessAs the new access equipment (access tunnel, cell, etc.) to be installed in the R/B is heavy equipment weighing
several hundred tons, technology for connecting the heavy structures to the PCV by means of remote operation
will be developed.

Items to be explained[2] Confinement structure for the connection parts
As the equipment to be newly installed needs to be equipped with the function of absorbing displacements inthe event of an earthquake in addition to a confinement function for the connection parts, a displacement
absorption structure for the PCV connection parts will be developed.

425 tonSlide part
Load
supporting
point©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.71

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access
STEP.1 Initial delivery

STEP.2 Rotary delivery

STEP.3 Straight line delivery

STEP.4 X-Y adjustment

Opening of
biologicalshieldLocation of R/B outer wall

Jack

Jack

Technology pertaining to bridges
Rotation

Access tunnel

Technology pertaining to bridges(application)

New technology
Access tunnel

Straight movement
Load

Load

Jack (4 units)Jack (2 units)

Sliding surface
Results up to FY2018(Approach & Systems
Upgrade)This project

Load

Access tunnel

Technology pertaining to bridges(application)
Access tunnel

Straight movement

Load

Slide part

Load

Jack (4 units)

X-Y adjustment jack (4 units)(There are issues in positioning whileconnecting)

The slide part has not been evaluated taking the load into consideration

Delivery through a narrow opening using a jack, and its precision will be verified with the help of a body simulating the shape(Common for Step 1, 2, and 3)
・Since the jack used was of the same capacity as the actual equipment, there will be no problem even with the actual mass.
・As the body simulating the shape was light in weight, the slide part has not been evaluated.
Verification of the function of the slide part with the help of a body simulating the mass (STEP 2)(In STEP 2, four jacks cannot be installed same as other STEPS, due to limited installation spaces.)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.72

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access
Procedure

Main issues
・Installation accuracy

Delivery equipment
installation

Access tunnel
assembly

・The installation accuracy, etc. of the delivery
equipment needs to be verified.

Study

Testing/Verification

Remarks

Done

Done

Implemented during thisproject

・Downsizing ofequipment

・The delivery equipment is required to be
downsized in order to shorten the delivery schedule(including preparations).

ーー

Implemented during the
Project for Developmentof Fuel Debris Retrieval
Method(Additional installation ofshield)・Assembly method

・The method of on-site assembly of the accesstunnel including internal components such as piping,etc. needs to be studied.

ーー

Implemented with actual
equipment engineering

・Passing throughconfined spaces
・Delivery accuracy

・Whether or not the R/B wall can be passed through(confned space) and the installation accuracy of theaccess tunnel needs to be verified.

ーー

Verified using the mockup simulating the shape
in FY2018

・Design of the slidepart・In the case of delivery by rotating, the access tunnel
needs to be rotated while sliding it using the slide part.
The design and performance of the slide part needs
to be verified.

Done

Done

Implemented during thisproject

・Connection structure

・The structure for connecting the access tunnel and
the PCV connection sleeve needs to be studied.

ーー

Implemented with actual
equipment engineering

DeliveryConnection

Details©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.73

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Issues]
In order to prevent the slide part from getting damaged while rotating the access tunnel, the surface pressure applied to the slide partneeds to be equal to or lower than the allowable surface pressure. Hence, the slide part needs to follow the lower surface of the accesstunnel (surface contact), so as to prevent application of localized force (line contact). There are several factors that have an impact on theability of the slide part to follow (shift in center of gravity of the access tunnel / manufacturing accuracy of the lower surface / the finishingof the lower surface / installation accuracy, etc.), and hence validation and verification need to be performed in advance.

[Implementation details]

The load when rotating the access tunnel
is received by the load supporting point
and the slide part•The structure of the rotating part (slide part) of the access tunnel will be studied
considering the impact of the load.

•

In order to verify the feasibility of the slide part that was studied, an element test plan 425[ton]including tests simulating the load on the slide part (simulating the mass of the actual
access tunnel unit at the time of rotation) will be drafted.

•

Element tests will be conducted to verify the feasibility of the slide part that wasstudied.
(The plan is to confirm the ability of the sliding surface to follow the tunnel body, inorder to verify feasibility)

Slide part[Expected outcome]•Loadsupporting
point

Illustration of the access tunnel slide partAn access tunnel slide part structure that considers the impact of the load will be presented.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.74

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for accessResults up to FY2018(Shape simulation)[Access tunnel slide part]
Slide part

R/B

425[ton]Slide part
Load
supporting
point

Load
supporting

Jack and rail
Sliding surface

・The plan is to install the access tunnel without removing existing pillars so as to minimize
the load on the damaged R/B.
For that, the access tunnel needs to be rotated in the vicinity of the R/B.
・The rear part of the access tunnel can be rotated on the rail by means of a jack,but there is no space to lay rails for rotating the front part. Hence the access tunnel will berotated (slid) by the slide part while bearing the load.
••••

Verification of delivery feasibility
Verification of delivery feasibility of thecurved shaped tunnel through the narrow
opening
Remote work monitoring (remote installation)
Verification of positioning accuracy(±50[mm])⇒ The feasibility of the access tunnel delivery was verified until FY2018 using shape
simulation.
The rotation of the access tunnel was tested as well, but as it was tested using a bodysimulating the shape and not the mass, this time verification will be carried out by means ofmass simulation.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.752) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for access[Role of the slide part]
Delivery direction

To ensure that the sliding surface follows (surface contact) the lower surface of the access tunnel so thatthe sliding surface is not subjected to excessive stress (line contact).

Access tunnel body

Delivery direction

X

Image showing thestatus after rotation
Since the access tunnel is bent, anoffset load gets applied to the slide part.

Maximum deflection

Maximum deflection
Maximum deflection

X
Rotation jackRotating rail

Bearing / bearer beam

After rotation

Before rotation[The studied slide part]Arrow X(The load on the slide part is analyzed, and the material of the bearings is studied.)
Access tunnel bodySliding surface(Sliding plate)

The technology concerning bridge bearings isapplied so that the sliding surface follows(surface contact) the lower surface of theaccess tunnel.
(Eccentric load + shift in center of gravity)

Bearings

Support beam
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.762) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Shape of the simulated structure of actual equipment]
4500

2550

W Gr.3
App.110[ton]W Gr.2
App.110[ton]Supporting point ofrotation and jack

Cross section of the simulated
structure simulating actual equipment

Position of sliding
pad after rotation

W Gr.1
App.110[ton]Position of sliding
pad before rotation

Bird’s-eye view of the simulated structure of actual equipment
Test case (ton)TargetCase 1Case 2

Case 3

Case 4

W Gr.3

－

－

－

93

W Gr.2

－

－

102

102

W Gr.1

－

103

103

103

Frame

132

132

132

132

Total

132

235

337

430

Flame
App.130[ton]The tendency was verified by
testing multiple cases.
→ Applicable even if the weight of
the actual equipment changes(Analysis results are used as well).
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.772) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access
Test Image[Slide part and delivery equipment]

Simulated
R/B opening

The slide part is installed using the center core of the simulated opening as reference.
Guide jackSliding surface(Sliding plate)
OutdoorSlide part

Rail for the rotation
jack

Inside R/B(Actual equipment:
not required)

Slide part

(Simulated R/B opening is installed during the test. The opening is made 5060[mm] wide
assuming the conditions in Unit 1.)

Not by means of remote operation: Preliminary
work (installation of delivery equipment, etc.)
By means of remote operation: Work ofdelivering the access tunnel©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.782) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for access
For development and test manufacturing[Equipment configuration (comparison with actual equipment)]
ID:

[1]

[2]

[3]

Actual equipment specifications*

Equipment

Mock-up specifications*➢➢➢➢

Cross-sectional dimensions: width 4.5 x height 2.4[m]Shielding thickness: not considered (frame structure)
Rotating unit: (Access tunnel unit 1 to 5)
Weight: Actual equipment mass is simulated by means ofweight(Approx. 130[Ton], 230[ton], 330[ton], 430[ton])➢ Sliding surface: Stainless steel polishing

Access tunnel body

➢
➢
➢
➢
➢

Slide part

Sliding section➢ Sliding surface: Sliding plate➢ Allowable surface pressure: 49[MPa] (500[kgf/cm2])➢ Allowable speed: 100[m/min]➢ Friction coefficient: 0.04 to 0.2
Guide jack
➢ Jack: Capability (pushing) approx. 50[ton] x 2 units➢ Jack: Stroke 1000[mm]Same as actual equipment specifications(Bearings made of stainless steel and rubber are madeavailable.)

Delivery mechanism

➢
➢
➢
➢

Same as actual equipment specifications

Cross-sectional dimensions: width 4.5 x height 3.1[m]Shielding thickness: 300[mm](Base 110[mm])Rotating unit: (Access tunnel unit 1 to 5)
Weight: 425 [ton]Sliding surface: Stainless steel polishing

Rotation jack: Capability (pulling) approx. 40[ton] x 2 units
Rotation jack: Stroke 1200[mm]Vertical Jack: Capability approx. 200[ton] x 2 units
Vertical jack: Stroke approx. 230[mm]425tonIllustration
Slide part
Load
supporting
point©International Research Institute for Nuclear Decommissioning*The actual equipment specifications and the mock-up specifications are all from the planning stage and are likely to change.

6. Implementation Items of This Project

No.79

2) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for access[Comparison of the options for the slide part]

Bearings(Stainless steel)

Bearings(Rubber)
Stainless steel bearings

SP※

Rubber bearings

SP mounting base

Bearing mounting base

※ SP: Sliding plate©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.80

2) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for access[Rotation jack specifications]Rotation jacks: 2 units
Equipment specifications
Vertical load
2000kN
Sliding surface bearing pressure 114kgf/cm2
Mass
310kg
(Excluding the vertical jack)The actual equipment andthe mock-up simulating
the shape have the same
capacity and stroke.

Specifications
Capacity
Pull 400 kN
Stroke1200mmPiston size
160mm
Ram size
120mm
Pressure receiving area 88.0cm2
Working pressure
45.47MPa
Required amount of oil 10.6L

Specifications
Capacity
Push 800 kN
Stroke1200mmPiston size
160mm
Pressure receiving area 201.1cm2
Working pressure
39.79MPa
Required amount of oil
24.1L
Mass
460kg

Specifications of the vertical jack
Model
Capacity
StrokeWorking pressure
Mass

ACRL-20023SB
2000kN
230mm
70.54MPa
260kg©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.812) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Guide jack specifications]

Guide jack: 2 sets (4 units)

Specifications
Capacity
Pull 200 kN
Stroke1000mmPiston size
115mm
Ram size
90mm
Pressure receiving area 40.3cm2
Working pressure 46.69MPa
Required amount of oil 4.1L

Specifications
Capacity
Push 500 kN
Stroke1000mmPiston size
115mm
Pressure receiving area 103.9cm2
Working pressure 48.14MPa
Required amount of oil 10.4L
Mass
approx. 175 kg

The actual equipment and the
mock-up simulating the shape havethe same capacity and stroke.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.822) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for accessPurpose of development: To make it possible to deliver with the help of rotation jack → with surface pressure as
per the design → and the bearing part functioning[Test plan]
ID:

1

2

3

4

Items

Items to be monitored,measured and recorded

Details

Delivery of simulated
structure of actual
equipment

Frictional resistance ofsliding surface⚫ Delivery of simulated structure of actual equipment will be tested.
⚫ Delivery speed: approx. 1[°/min] (160[mm/min])⚫ Will be rotated from 0 - 45° with a 5° movement each time, and each item will bemeasured.

➤ Rotation jack propulsiveforce⚫ The friction coefficient of the sliding surface (sliding plate) will be verified based on
the rotation jack propulsive force.

➤Calculation of the friction
coefficient(Comparison with thespecifications)

Ability to follow thesliding surface⚫ Measurement points will be set up, and the gap between the sliding surface andbottom plate of the simulated access tunnel frame as well as the inclination of theslide part will be verified before and after delivery.
(Implemented in the area where the gap and inclination can be verified)

Confirmation of
reproducibility⚫ Tests will be conducted multiple times to verify whether the items to be monitored
are reproduced.

➤ Gap between the sliding
surface and the tunnel frame

Criteria
Is able to deliver.
(Rotation jack propulsive force≦40[ton]/unit)
Is within the range of
specifications of the sliding
surface.
(Friction coefficient: 0.04 to 0.2)

ー➤Inclination of the slide partSame as items 1 to 3 aboveー(Remarks) This plan is likely to change depending on the progress in designing.

Simulated tunnel frame

Rotation jack
Gap
Rotating rail

Delivery direction
Propulsive force

Slide part

Items to be monitored,measured and recorded©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.83

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Number of tests]
The tests shall be conducted using stainless steel bearings or rubber bearings. From the results of prior evaluation,
stainless steel bearings are effective*1 in the case of actual equipment, but as rubber bearings are advantageous interms of taking in inadequacies in manufacturing accuracy, installation accuracy, etc., the rubber bearings shall betested as a back-up for stainless steel bearings.
This mock-up test will be conducted 3 times for each load case of stainless steel bearings, and 2 times for each loadcase of rubber bearings. Note that, load case 3 of rubber bearings shall not be tested due to test schedule constraints.
List of testing conditions
Test No.

1

Bearings material

Load case*2(Delivery load)

Delivery frequency

2

3

4

5

6

7

Made of rubber*3

Stainless steel
Case 1(130ton)Case 2(230ton)Case 3(330ton)Case 4(430ton)Case 1(130ton)Case 2(230ton)Case 4(430ton)132 [ton]

235 [ton]337 [ton]

430 [ton]

132 [ton]

235 [ton]

430 [ton]

3 times each

2 times each

*1: As per the analysis results, in the case of rubber bearings, the stress on the sliding plate is maximum 44[MPa]. Although it is within the range ofallowable surface pressure of 49[MPa], the pressure is extremely high.
Hence, stainless steel bearings (maximum 17.8[Mpa]) are being studied as the first option for the actual equipment.
*2: The actual measured load is reflected in each case.
*3: Even though load case 3 (330ton) of the rubber bearings is not tested, it will be discussed based on results of testing the other cases.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.842) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for accessMeasurement: Mass

[Measurement / Verification items]
For the test the structure will be rotated 45° from the state shown in the
figure below. It will be stopped at approx. 5°pitch, and the items listed in
the table on the right will be verified. The various data pertaining to the jackat the time of movement will be recorded in the data logger.
Mass: [1] to [2], Force： [3] to [5], Displacement： [6] to
[14]

[2
]

[1
]

[4]

[1 [1
2] 4]

[8]
[8]
[8]

[1
0]

Mass of body simulating actual equipment (at the time of manufacturing)[2]

Weight and mass (at the time of manufacturing)

Measurement: Force (Load/propulsive force)[3]

Rotation jack propulsive force[4]

Rotation jack vertical load

[5]

Guide jack propulsive force

Measurement: Displacement

[1
3]

[7]

[1]

[6]
[1
1]
[7][5][3][6]

Stroke of the vertical section of the rotation jack[7]

Guide jack stroke[8]

Displacement at the distal end of the simulated structure[9]

Gap with the simulated wall

[10]

Parallelism 1 of test specimen[11]

Parallelism 2 of test specimen[12]

Gap with the sliding plate (if possible)[13]

Trajectory of the body simulating actual equipment[14]➤ Height of the slide part (Inclination)

Verification: External appearance[15]

Surface of the sliding plate

Verification: Calculation

The following will be analyzed and compared with the design value:
Rotation jack propulsive force and vertical load / Displacement on the distal end /Load on the bearing part

[16]

Load on the bearing part (= Total weight - Rotation jack vertical load)[17]

Friction coefficient＝Rotation jack propulsive force / Load on the bearing
part©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.852) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Measurement method (measuring instrument)]
Measurement will be performed directly using a steel rule, etc. The displacement of the access tunnel simulated
structure is measured by measuring the measuring tape attached to the simulated structure using a theodolite.

Floor plan

Left side view

Laser level marker

Theodolite

Measuring tape

Steel rule, gauge, etc.

Front view・ The locations circled in red in the figure show the location where the measuring tape is
attached.
・ The benchmark will be considered as the guideline for measurement. Refer to the next page forthe location of the benchmarks.
・ Data pertaining to the jack (pressure, stroke) will also be acquired separately.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.862) Development of technology for connecting heavy structures for accessing PCV and the confinement structure forthe connection parts[1] Technology for connecting heavy structures used for access[Measurement method (Benchmark scheme drawing)]
Theodolite installation location [1]Main benchmark

Benchmark [2]Hydraulic system (6 units)

Rotating
propulsion jack

Bearer beam

Operating room
Electrical panel

Center of rotation of the AT test specimen
Simulated wall opening

Partition

Delivery direction
Common frame
AT test specimen
Rail for rotation

Bearing

Temporary storage
area for materials

Guide jack

Theodolite installation location [3]Benchmark [1]Theodolite installation location [2]©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.872) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[1][Measurement method (camera for recording)]

Delivery direction
Hydraulic system (6 units)

Rotating
propulsion jack

Camera [1](Height: Approx. 15m)

Bearer beam
Center of rotation of the AT test specimen[2]

Electrical panel

Simulated wall opening

Camera [2][3]Partition

Common frame
AT test specimen

Camera [4]Camera [3][4]©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.882) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Recording of the installation of the slide part and the rail]
Recording (in the direction of the height) of the installation of the slide part (red frame)
and the rail part (blue frame) is indicated. Installation was performed considering atarget ±5mm. Also, JIS B 0405 V (extremely coarse class) was used for installation in
the planar direction. Installation has been completed in the direction of the height and in
the planar direction within the given range of accuracy.

[Verification at the time of installing the main body of the access tunnel]
When the access tunnel main body was installed on thedelivery equipment, the height of the slide part and the height ofthe connecting part of the rotation jack and access tunnel(parallelism of the access tunnel) were verified. It was found that
it is important to adjust these heights as much as possible.
During the test adjustments were made in the range of ±2[mm]and the delivery was carried out.

1

-2

(Blue guideline)

0

0

-2

(Red guideline)

-1

0
1

0

0

1

Access tunnel main structure

1

2

Slide part

2
Adjusting the heights

There is a jackfor verticaladjustment.

22©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.892) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for access[Results of element tests]⚫ The test results are indicated here.
⚫ In the case of stainless steel bearings, thesliding plate got worn out earlier than expected
and the initially planned number of rounds did
not get completed. However, since the data
can be reproduced, it was determined that
there was no problem even if it was able to
make 2 rounds.
⚫ It was evaluated that the stainless steel
bearings were better. Although the frictional
resistance is almost about the same, since therubber bearings get flattened, adjusting theposition in the direction of the height is difficult
as compared to the stainless steel bearings.
⚫ Test No. 4 and 5 onwards, as repeat tests wereconducted, the top surface of the rails forrotation got bent (plastic deformation), thereby
leading to a condition in which the rotation jackis likely to get tilted as mentioned later. The test
was discontinued at an early stage due to thebending of the upper surface of the rail for
rotation.

SP No.: Sliding Plate No.

No.
0-1

Test load / round130 [ton]

Trial Run

Bearings
material

Test results

SP No.

Stainless
steel

―

1

Rotated up to 45°―

2Rotated up to 20°

○

2

○

2

○

2

Remarks

Sliding plate replacement
0-2
1
2
3

430 [ton]

Trial Run

230 [ton]

1st round

230 [ton]

2nd round

330 [ton]

1st round

Stainlesssteel

Sliding plate replacement
4

430 [ton]

1st round△3

Discontinued at around40°

5

430 [ton]

2nd round△3

Discontinued at around35°

6

330 [ton]

2nd round△3

Discontinued at around35°

7130 [ton]

1st round○3

130 [ton]

2nd round○39130 [ton]

1st round

○

4

10

130 [ton]

2nd round

○

4

11

230 [ton]

1st round

○

4

12

230 [ton]

2nd round△

4

Discontinued at around43°

13

430 [ton]

1st round△

4

Discontinued at around18°

14

430 [ton]

2nd round△

4

Discontinued at around18°

8

Stainlesssteel

Bearings sliding plate replacement

Rubber©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.902) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for accessOutward propulsion load
Inward propulsion load
Propulsion load (total)
Vertical load (total)
Bearing part load

Friction coefficient

Friction coefficient

Load on jack [kN]

[Results of element tests (stainless steel
bearings)]⚫ The results of the 330 [ton] delivery
equipment are indicated here.
⚫ 330[ton] load was delivered with apropulsive force of approx. 50[ton]/2 units.
Friction coefficient shifted between 0.09 to
0.16.
・ Jack capacity (propulsive force) was 80[ton]/2
units.
・ Propulsive load = propulsive force

330ton_First round

Angle©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.91

2) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[1] Technology for connecting heavy structures used for accessOutward propulsion load

430ton_First roundInward propulsion load
Propulsion load (total)
Vertical load (total)
Bearing part load
Friction coefficient

Friction coefficient

Load on jack [kN]

[Results of element tests (stainless steel
bearings)]⚫ The data pertaining to the conditions at thetime of delivering 430 [ton] are indicatedhere.
⚫ Friction coefficient has shifted between 0.09
to 0.14.
⚫ Jack propulsive force is approx. 50[ton]/2
units.
・ Jack capacity (propulsive force) is 80[ton]/2
units.
・ Propulsive load = propulsive force⚫ There is a problem in the structure of thejack, and hence delivery could not be madeup to 45° (rotated up to 40°).
⚫ The frictional resistance is within the design
values. There is margin for load on the
propulsion jack. With the current structure of
the jack, even though delivery up to 45°is
not available, it is evaluated that delivery
using an actual equipment is available if
revising the jack structure.

Angle©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.922) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Evaluation of the tilting phenomenon of the rotation jack saddle]
The test was discontinued as the saddle of the rotation jack tilted. The ball joint part got bent due to which the
propulsive force could not be transmitted.

Direction of movementof the rotation jack

W: Vertical load
F: Resistance
H: Height of the saddle

Ball joint
SaddleRail for rotation
W: Vertical load
Access tunnel body

F: ResistanceSlide part

L: Width of the saddle
Conditions under which it tilts

F・H > W・L/2
Over-turning
MomentLoad Capacity

3°

Measures (proposed): Studying the structure of the balljoint, increasing the width of the rail, reducing the heightof the saddle etc.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.932) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Evaluation of the tilting phenomenon of the rotation
jack saddle]
It was found that the over-turning moment waslarger than the load capacity of the jack in thevicinity of 35°. The test was finally discontinued
when the tilting of the jack was the largest in thevicinity of 40°, but the jack had actually started
tilting in the vicinity of 30 to 35°.

Assumed value(430ton[1st time])

Comparison of the over-turning moment

Over-turning moment> Load capacity

Over-turning moment < load capacity

Over-turning
momentLoadcapacity

W: Vertical load
F: Resistance

Moment [kN/m]

F・H > W・L/2

Over-turning moment
Load capacity

H: 680[mm]Angle

L: 400[mm]©International Research Institute for Nuclear Decommissioning

Rotational angle [ °]Conditions under which it tilts

6. Implementation Items of This Project

No.94

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Evaluation of the tilting phenomenon of the rotation jackAssumed value (430 [ton] [1st time]saddle]Comparison of the over-turning moment (after improvements)
in case the improvement is made)The assumed values if the distance between the top
surface of the rail for rotation and the lower surface of
the access tunnel is reduced (680→400) to reduce theOverturning moment at all times＜ load capacity
over-turning moment, and further if the width of the rail
for rotation is increased （400→600）to increase theresistance force of the jack, are indicated in the figureon the right. It is evaluated that the situation can be
resolved by revising the width and height.

F・H > W・L/2
W: Vertical load
F: Resistance

Moment [kN/m]

Improved overturning moment
Improved load capacity
Angle

Does not get reversed

Rotational angle [ °]Conditions under which it tilts

H: 400[mm]

L: 600[mm]©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.95

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[1] Technology for connecting heavy structures used for access[Implementation status of element tests]⚫ The surface pressure on the used sliding plate and on the
bearings used for analysis was compared.
⚫ It was found that the sliding plate gets worn out when thesurface pressure is high, and the coating decreases (getsworn out).
⚫ It shows that the results of analysis and delivery testing are
the same. Thus it is assumed that analysis and evaluation
would be possible using the actual equipment as well.

0° rotation

Maximum
62.9MPa

15° rotation

45° rotation

30° rotation

Maximum
67.1MPa

Maximum
53.1MPa

Maximum
72.6MPa©International Research Institute for Nuclear Decommissioning

No.96

6. Implementation Items of This Project2) Development of technology for connecting heavy structures for accessing PCV andthe confinement structure for the connection parts[1] Technology for connecting heavy structures used for access： Summary➢The slide part (stainless steel bearings and rubber bearings) used for delivering
the access tunnel by rotating it was studied as a method for remotely connecting
the access tunnel, which is a heavy structure, to the PCV. Element tests wereconducted on each type of slide part using mock-ups simulating the actual
weight. The weight was changed and the possibility of delivery, the frictional
resistance of the slide part and ability of the slide part to follow were verified.
➢ In the case of stainless steel bearings, it was verified that 330[ton] can bedelivered by means of rotation, and while delivering 430[ton] as well, thefrictional resistance was under the design value. While delivering 430[ton],rotation could not be completed till the end (0° to 45°) due to problems in the
structure of the jack. But delivery by means of rotation is expected to become
possible by modifying the structure of the jack.
➢ As a result, the structure of the slide part showed in No.75 (stainless steel
bearing material) is likely to be used for delivery of the access tunnel.
➢ The issues related to the method of delivering (rotation) the access tunnel wereclarified based on the results of the element tests.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.972) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts
Development items involving solicitation

Implementation policy (proposed)

Remarks

1) Development of an air-tight mechanism forlarge transfer containers

With respect to retrieving fuel debris and reactor internals, the method of transferring the unitized large
structures is being studied in order to improve the throughput for the top access as part of the development
being undertaken since FY2019. In order to transfer large structures, it is necessary to develop large transfer
containers with a function for preventing the spread of contamination and shielding function for high radiation
items stored in containers.
Upon studying the pre-conditions for the large transfer containers and the required development items, an airtight mechanism for the lid of the large transfer container will be developed. And, the criticality control method
for the period from after collection of the structures until they are stored, will be studied.

2) Development of technology for connecting
heavy structures for accessing PCV
and the confinement structure for theconnection parts[1] Technology for connecting heavy structures used for accessAs the new access equipment (access tunnel, cell, etc.) to be installed in the R/B is heavy equipment weighing
several hundred tons, technology for connecting the heavy structures to the PCV by means of remote operation
will be developed.

Items to be explained[2] Confinement structure for the connection parts
As the equipment to be newly installed needs to be equipped with the function of absorbing displacements inthe event of an earthquake in addition to a confinement function for the connection parts, a displacement
absorption structure for the PCV connection parts will be developed.
Displacement
変位吸収機構absorption
mechanism

Sleeveスリーブ

Welding
溶接
PCV(equipment hatch)

PCV(機器ハッチ)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.98

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Issues]
In order to absorb the displacement of the access tunnel (including sleeve) and the PCV in the event of an earthquake, a displacement
absorption mechanism will be installed on the sleeve. However, the issues is that existing technology (expansion type bellows, etc.)
cannot be applied due to various limitations. Hence, displacement absorption technology that takes large size/confinement/structure
viability/manufacturing efficiency/long-term integrity into consideration, needs to be developed.
Displacement
absorption mechanism

Sleeve[Implementation details]•

The displacement absorption mechanism to be installed at the connection part thatconnects the access tunnel with the PCV, which absorbs the displacement caused in
the event of an earthquake, etc. and takes the confinement function (airtightstructure) into consideration, was embodied.

•An element test plan required for verifying the feasibility of the displacement
absorption mechanism that was studied, will be developed.

•

Element tests were conducted to verify the feasibility of the displacement absorption
mechanism.
(Movement verification and air-tightness verification will be conducted in order toverify feasibility.)[Expected outcome]•An access tunnel connection part structure (displacement absorption
mechanism) that retains the confinement function and is able to absorb thedisplacement in the event of an earthquake, etc. will be presented.

Welding

PCV(Equipment hatch)

The main body of the sleeve is being
studied under the Project for Developmentof Fuel Debris Retrieval Method

An example of the connection part structure©International Research Institute for Nuclear Decommissioning6. Implementation Items of This Project

No.99

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Overview of the displacement absorption mechanism]
Access tunnel
Displacement absorption mechanism
・ As the sleeve and the tunnel are fixed and move together with the R/B as a whole in theevent of an earthquake, the displacement absorption mechanism will be installed on the PCVside of the sleeve.
(A maximum of ± 12.5 [mm] displacement is expected*)・ As the sleeve needs to bear the load of the tunnel, load bearing and displacement
absorption are required within approx. 1800 mm which is the thickness of the biologicalshielding wall.
⇒ Considering load bearing, approx. 350[mm] of this can be used for the displacement
absorption mechanism.
If the displacement of ± 12.5 [mm] is to be absorbed only by means of bellows, it would
require 1000 [mm] or more and hence a new mechanism needs to be developed.
A

Estimation of displacement[mm]*
Horizontal (Xaxis, Z axis)

Approx. 1800[mm](BSW thickness)±12.5

Vertical (Y
axis)

±0.2

±0.2

Z Axis

±12.5

Biologicalshielding wall
(BSW)

Load supporting point

Y AxisX AxisPCVApprox.
350[mm]

BSW

Displacement between R/B(BSW) and PCV(equipment hatch)

Sleeve±12.5

Face to facedimensions [mm] of
the area where thedisplacement
absorption mechanism
is installed
Approx. 350

A
Front side of theequipment hatch

Equipment
hatch

Cross section A-A

The displacement absorption mechanism installation location has dimensional constraints, has high radiation levels and is narrow. Based on the results of the studies conducted aspart of the FY2019 Subsidy Project, the displacement absorption mechanism, including the maintenance method (necessity/monitoring method/inspection method, etc.) after it has
been installed, will be studied.
©International
Research
Institute for
Nuclear Decommissioning*Set up based on the contents of the report on Subsidy Project of Decommissioning and Contaminated Water Management in the FY2015 Supplementary
Budgets“Developmentof Assessment
Method for
Seismic Resistance and Impact of Pressure Vessel and Containment Vessel” (Operation floor additional equipment: 6100 [ton], Seismic ground motion: 900[Gal])6. Implementation Items of This ProjectNo.1002) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Required specifications of the displacement absorption mechanism]
Item

Specifications

Basic requirements
Environmental
conditions

Functional requirements

Should be able to confine radioactive materials.

Absorption of
displacement

Horizontal ±12.5[mm], vertical ±0.2[mm]Design differential
pressure

The connection part should remain sound in response to the design
differential pressure (400[Pa]).

Reduction in radiation
exposure of workers

Maintenance work by means of completely remote operation should bepossible.

Design life

50 years

Dose rate(R/B First Floor) 5 to 10[mSv/h], (in the vicinity of PCV shell external wall) 10
to 100[Sv/h]

Temperature-7 to 40℃

Humidity≦100%

Displacement
absorption
mechanism

Expandedbuilding

Main cell

Equipment hatch
shell

R/B

Secondaryboundary
Primary boundary

Access tunnel

PCV©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.101

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Structure of the AT sleeve]
・ Displacement absorption mechanism: Absorbs displacement in theevent of an earthquake
・Reaction force jack: Adjusts the reaction force after connecting theaccess tunnel
・ Positioning jack: Adjusts the position while installing the sleeve

Worm speed reducers (MAKISHINKO MAO100)

Reaction force jack
50[Ton] × 2 units

Robot connection bolt

Speed reduction ratio 30

Remote operation nut
Connector for the motor
Same as the other side

X AxisY AxisView X
AT sleeve installation diagram

Z AxisView X

Positioning jack
25[Ton] × 4 units

Displacement absorption
mechanism(Scope of simulation in thisproject)

PCV
side
Equipment
hatch©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.102

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Displacement absorption mechanism boundary (wedge type)]
Displacement
absorption mechanism

Sleeve side

Sliding flange
Bellows

Leak path

Wedge adjustment bolt
(Push pull)

Sliding surface

Boundary

PCV sideA

Y(±12.5)

X(±12.5)Sleeve side
A

Taper

X
(±0.2)

Sleeve
side

PCV
side

Wedge

Equipment hatch
shellY(±12.5)

X(±12.5)

Welded part

PCV sideStandalone displacement absorption mechanism(The plate (blue) welded to the equipment hatch is omitted.)

Crosssection
A-A

Sliding flange

Displace
ment axis

Response

X

BellowsY

Sliding flangeZ

Sliding flange©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1032) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Modification of the structure]
The method for pressing in the sliding flange by using a wedge (left side in the figure below) was being studied, but as a resultof verifying the movement using a scale model it became evident that it would be difficult to adjust the surface pressure. Hence, aspring type structure was studied.
MethodWedge typeSurface to bepressed on

Spring typeSurface to bepressed on

Sealed surface
Wedge adjustment bolt
(Push pull)

Taper

Sealed surface

Spring(Total 18 coils)

Slidingsurface

Illustration

Press fitting
Wedge

Sliding flange

・In the figure, PCV is on the left side and Thrust mechanism details
the sleeve is on the right side

Sliding flange
・In the figure, PCV is on the left side
Thrust mechanism details
and the sleeve is on the right side

Merits・Requires lesser number of components as compared to the spring typestructure.
・Maintenance is not required.

・Surface pressure adjustment during assembly is easier than the wedge typestructure.

Demerits

・It is difficult to adjust the surface pressure using the wedge adjustment bolt.
・The structure is rigid and lacks flexibility.

・Requires more number of components as compared to the wedge typestructure, and hence there is higher risk of failure.
・The spring is expected to deteriorate, etc. and will need to be replaced.

Since both methods have merits and demerits, tests for both methods were conducted to confirm the leakage rate.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1042) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts Wedge adjustment bolt

[Outline of the structure](Push pull)

Spring(Total 18 coils)

Sliding surface

Sliding surface
Taper

Fixed flange
Wedge
Wedge
Wedge adjustment bolt
(Push pull)

Sliding flange

Fixed flange

Pressing fitting
Sliding flange

Wedge type

Spring typePress fitting

Spring(Total 18 coils)

Fixed flange

Sliding flange
Wedge type (the gray section of the cross sectional view is not shown in the figure) Spring type (the gray section of the cross sectional view is not shown in the figure)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1052) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Material of the lapping section and surface finish]
At present, the sliding flange and fixed flange are both planned to be made of stainless steel. Since it is a metal touch module,in order to enhance the sliding performance (improved proposal), a thermal spray of tungsten carbide is planned to be performedon the sliding surface. After the thermal spray the surface will undergo polishing to achieve an effect equivalent to Ra1.6. As thesliding flange is large, manufacturing efficiency will be verified in terms of thermal spraying.
Surface to bepressed on
Item

Sealed surface

SUS304(Ra1.6)(Main proposal) SUS304(Ra1.6)

Sliding flange (Orange)(Improved proposal) Tungsten carbide
thermal spray(Polishing equivalent to Ra1.6)(Main proposal) SUS304(Ra1.6)

Surface to bepressed on

Sliding flange

Sealed surface

Press fitting/ wedge

Material of the sliding surface

Fixed flange

Fixed flange (Blue)

Specifications

Sliding flange (Purple)(Improved proposal) Tungsten carbide
thermal spray(Polishing equivalent to Ra1.6)

Press fitting or wedge (Green)

SUS304(Ra1.6)

・In the figure, PCV is on the left side and the sleeve is on the right side
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1062) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts
Test rack[Test apparatus]

Test rack

Closing lid

Closing lid

Jack for testing
Jack for testing

Sleeveside

PCV sideθ(±0.54°)*2

Displacement is brought about in the X,
Y direction using the jack*1 for testing.
PCV side

It is assumed that as the estimatedamount of displacement in the Z
direction is ±0.2[mm], it can be ignored.
(As the sliding flange is crosssectionally identical from all directions,sliding is possible.)*1: The jack is used for testing. It is different
than the reaction force jack / positioning jackthat is planned to be installed on the sleeve.

*The figure illustrates thewedge type structureJack for testing

Displacement
absorption
mechanism

Z(±0.2)

Jack for testingY(±12.5)

X(±12.5)*2: The angle, when the bellows extend
12.5mm if the movement is in the θ direction,is set.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1072) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts
For development of prototypes[Equipment configuration (comparison with actual equipment)]
ID:

[1]

[2]

Equipment

AT Sleeve

Displacement absorption
mechanism

Actual equipment specifications*

Mock-up specifications➢ Shape: W3730 × D2200 × H2995➢ Weight: Approx. 25[ton]➢ Reaction force jack: 50[ton] x 2 units (operated by means of
trapezoidal screw thread / robot)➢ Positioning jack: 25[ton] x 4 units (motor operated cylinder)➢ Mechanism: Bellows (axial direction) + sliding flange➢ Amount of displacement: Horizontal 12.5[mm], vertical 0.2[mm],angle 0.54°(Note)➢ Displacement direction: X, Y, Z, Θ
➢ Sliding flange material quality: (The outcome of this project will
be reflected)―➢ Mechanism: Bellows (axial direction) + sliding flange➢ Amount of displacement: Horizontal 12.5[mm], vertical 0.2[mm],angle 0.54°(Note)➢ Displacement direction: X, Y, Z, Θ
➢ Sliding flange material quality: SUS304

PCV side

Access tunnel side

Illustration

PCV side
Access tunnel side
(Sleeve included)(Displacement absorption mechanism＋ Test rack)*The actual equipment specifications are from the planning stage and are likely to change.
Institute for Nuclear
Decommissioning(Note) Set up based on the contents of the report on Subsidy Project of Decommissioning and Contaminated Water Management in the FY2015©International
Supplementary Research
Budgets “Developmentof Assessment
Method for
Seismic Resistance and Impact of Pressure Vessel and Containment Vessel” (Operation floor additional equipment: 6100 ton, Seismic motion: 900Gal)

6. Implementation Items of This ProjectNo.1082) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Test plan]
ID:

1

2

3

Items to be monitored,measured and recorded

Item

Details

Criteria

Leakage rate

⚫ The pressure fluctuations before and after
the operation of the displacement
absorption mechanism shall be within thereference value.

➢ Pressure➢ Temperature➢ Surface pressure

Is within the prescribed range.
Leakage rate 0.12[m3/h] or less*

Amount ofdisplacement⚫ It will be verified whether or not the amountof displacement is met. Displacement isbrought about using a jack, etc. forverification.
⚫ Displacement takes place in the X, Y, Z, Θdirections.

➢ The stroke of the test jackused for changing theamount of displacement

Prescribed amount of
displacement is achieved.
Horizontal ±12.5[mm] or more

Displacement
traceability⚫ Operation is performed multiple times
while changing the direction of
displacement, to verify displacement
traceability. After the operation, the leakrate is verified.
(Performed using a simple equipment (jack,etc.) rather than an excitation equipment.
Displacement is considered to be ± 12.5[mm].)➢ Outer appearance(occurrence of damaging
scratches)➢ Sound during operation

Is within the prescribed range.
Leakage rate 0.12[m3/h] or less*(Remarks) *Calculated as [0.1[vol%] of 120[m3], which is the volume of the access tunnel, based on the design basis of the cell.

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1092) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Configuration of the measuring
instruments for the test]

A.PC

B. USB cable

K. Load cell

C. Recorder

Area outside the test specimen

D shunt resistor
250Ω

F.
Thermocouple

D shunt resistor
250Ω

J. Aethrioscope
H. Thermocouple

Pressure
vent

E. Pressure
gauge

E. Pressure
gauge
Needle valve(Nylon tube)

E pressure gauge
Fine pressure
difference transmitter(Nagano Keiki GC15)

E pressure gauge
Atmosphere
Fine pressure difference
releasetransmitter (Nagano
Keiki GC15)(Hose: transparent)

No.

Name of component

Model No. (Size, etc.)

A

CompupterB

USB cable

C

RecorderD

Resistance 250ΩE

Fine pressure difference meter

Nagano Keiki（GC15）

F

Thermocouple (with joint)

K typeG

Barometer

BAN-331A-1KPA

H

Thermocouple

K typeI

CablesJ

Precision barometer

PTB330K

Load cell

For 500kN

Connection port

(Hose: Orange)

Air(Nylon tube)

Atmosphere release.

Mastervalve

Laptop computer
Hioki LR8430©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1102) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Leakage test parameters]
No.

MethodThermalspray

Amount of displacement[mm]
X direction

Y direction

0

0

±12.5

0

0

±12.5

±12.5

±12.5

0

0

±12.5

0

7

0

±12.5

8

±12.5

±12.5

9

0

0

±12.5

0

0

±12.5

±12.5

±12.5

0

0

±12.5

0

15

0

±12.5

16

±12.5

±12.5

1
2

4

A

TestingpressureZ(±0.2)
Y(±12.5)Absent3

X(±12.5)

PCV side

Spring type
5
6Standalone displacement
absorption mechanism

Present

Leak path

500[Pa]10
Absent
11
12
13

Wedge
type

14

A

Sleeve side

Sliding flange

Bellows

BoundaryY(±12.5)Sleeve sideX(±12.5)

PCV side
Equipment hatch
shellPresent

Welded part

Cross-section A-A©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.111

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Test apparatus]

Fixed flange side

Sliding flange side
(Not included in the 3D figure)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.112

2) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Test apparatus]
Bellows

Fixed flange

PCV side

Sliding flange

Access tunnel side

ThrustSliding surface
State the thrust mechanism (wedge and spring) are not installed.
©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1132) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Test preparation (Pretesting)]
The test rack is laid sideways, bellows and closing lid (for pretesting) are installed on it, and air-tightness is tested. It is verified
that there is no leakage. Similarly, the fixed flange is tested, and it is verified that there is no leakage other than from the lapping
section.
PCV side

Sleeve side

Fixed flange

Sliding flange

Bellows

Pretesting
Test rack

Area captured in
the photo (left)

Fixed flange side

Sliding surface©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1142) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Test preparation]①②③

The contact surface of the sliding flange and the fixed flange is checked using carbonless duplicating paper.
The surface pressure is measured with a pressure sensor by installing it on the test apparatus.
The surface pressure is adjusted using the thrust mechanism.

Carbonless duplicating paper(The photo is taken at the
preparation stage)

Pressure sensor

Pressure measurement©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1152) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Preliminary test]
The test rack and the fixed flange are laid sideways, the sliding flange is installed on top and elevated pressure test is
conducted. It is verified that a pressure of approx 400[Pa] is maintained for 30 minutes.

Air-tightness verification FP (no thermal spraying) 180 ° rotation 2/17/2022

Closing lid

Approx. 30 minutes
Fixed flange

Sliding flange(Thrust on the fixed flange is solely from the self weightof the sliding flange.)

Fine pressure
difference
meter

Fine pressure
difference
meter

Thermometer - factory[ °C]

Internal thermometer [ °C]©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1162) Development of technology for connecting heavy structures for accessing PCV and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Verification of displacement traceability (wedge type) (1/2)]
After assembling the equipment, the sliding movement was verified. The sliding resistance was 6.8[kN] or less. Sliding resistance
was approx. 2[kN] when there was no thrust. Hence the sliding resistance due to thrust was approx. 5[kN]. Under such conditions theleakage test was conducted. As a result of the test, leakage was 0.063[m 3/h]. The surface pressure and the gap between the sliding
flange and fixed flange was as given below.
After operating multiple times, the equipment was disassembled and re-assembled. At that time, no significant scratches were foundon the sliding surface.

Results of measuring the surface pressure and gap

0.05 [mm]0.01 [mm]0.06 [mm]0.03 [mm]Pressure scale (Cal)©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1172) Development of technology for connecting heavy structures used for access and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Verification of displacement traceability (wedge type) (2/2)]
The equipment was assembled once again, the sliding movement was verified and the leakage test was conducted.
The leakage test results are indicated on the next page. The sliding resistance was 30 to 90[kN]. After conducting the
air-tightness test, when the equipment was disassembled and the sliding surface was checked, there were somescratches on the sliding surface. As shown by the results of measuring the surface pressure, surface pressure had
increased in some parts, and that is assumed to have resulted in the scratches and increased sliding resistance. It was
found that it is important to measure the surface pressure during assembly to check that there is no abnormal surfacepressure.
Pressure scale (Cal)Results of measuring the surface pressure and gap

0[mm]*

0.03 [mm]0[mm]*

0.07 [mm]* Feeler gauge of 0.01
could not enter.
©International Research Institute for Nuclear DecommissioningNo.118

6. Implementation Items of This Project2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Leakage test results (wedge type)]

As a result of the leakage test, it was found that the leakage rate was below the target leakage
rate of 0.12[m3/h] under all conditions. The sliding resistance was approx. 90[kN]( approx. 9[ton])or less. Since the allowable sheer stress of welded part, welded with the equipment hatch, isapprox. 27[ton], the welded part does not break in the event of an earthquake and sliding ispossible. Also, leakage test was conducted after performing the operation multiple times, and it
was found that the leakage rate was below the target leakage rate.
Amount of displacement [mm]θTesting
Pressure[Pa]

Leakagerate[m3/h]

0

－

500

0.047

+12.5

0

－

500

0.042

3

-12.5

0

－

500

0.063

4

0

+12.5

－

500

0.048

5

0

-12.5

－

500

0.052

6

+12.5

+12.5

－

500

0.053

7

+12.5

-12.5

－

500

0.047

8

-12.5

+12.5

－

500

0.060

9

-12.5

-12.5

－

500

0.060

10

－

－

+0.54

500

0.056

11

－

－

-0.54

500

0.050

No.

X
directionY
direction

1

0

2

A

Sleeve sideAZ(±0.2)
Y(±12.5)

X(±12.5)

PCV sideθ(±0.54°)Standalone displacement absorption mechanism
Leak path

Sliding flange

Bellows

Boundary(＋)

Y(±12.5)Sleeve side(－)

X(±12.5)

PCV side
Equipment hatch
shell

Cross-section A-A

Welded part©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1192) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Leakage test results (wedge type)]
The leakage test for assembled equipment was conducted. The leakage rate was approx. 0.047[m 3/h] and thus satisfied thetarget leakage rate of 0.12[m3/h].
[Test conditions] Wedge type/without thermal spray/reference position
In the end

Temperature inside the test
apparatus [℃]

11.7

11.7

Pressure inside the test
apparatus [Pa]

500.1

136.4

Atmospheric pressure [hPa]1015.41015.52

Time

14:03:32

14:18:32

Measurement time

15 minSliding resistance

10 [ton] or lessQ=

V𝑇20 𝑃2 𝑃1 V𝑇20 𝑃𝑎𝑡𝑚2 𝑃𝑎𝑡𝑚1−−[𝑃𝑎・ 𝐿Τ𝑠]
Δ𝑡 𝑇2 𝑇1 ＋ Δ𝑡
𝑇2
𝑇1

𝑞=

𝑄
[𝐿Τ𝑠]
101325

Leakage test at reference position

Temperature [°C]

While starting

Pressure [Pa]Item

Measurement time (m)Here, the leakage rate (Pa・L/s) is in terms of Q: 20°C
P1: Gauge pressure (Pa) of the test specimen when measurement starts
P2: Gauge pressure (Pa) of the test specimen when measurement ends
Patm1: Atmospheric pressure (outside pressure) (Pa) whenmeasurement starts
Patm2: Atmospheric pressure (outside pressure) (Pa) after
measurement starts
Δt : Time from start of measurement to end of measurement (s)V: Internal volume (L) of the test specimen
Atmospheric
T20: Reference temperature 293 (K)pressure [hPa]T1: Absolute temperature (K) of the gas
inside the test specimen when measurement starts
T2: Absolute temperature (K) of the gas inside the test specimen whenmeasurement ends
q: Leakage rate (L/s) in terms of 20℃ and 1 atmospheric pressure

Pressure inside the test
specimen (1)Pressure inside the test
specimen (2)Temperatureinside the factory

Temperature inside
the test specimen©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1202) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Leakage test results (wedge type)]
The leakage test for assembled equipment was conducted. The leakage rate was approx. 0.063[m3/h] and thus satisfied thetarget leakage rate of 0.12[m3/h].
[Test conditions] Wedge type/without thermal spray/X-12.5[mm]In the end

Temperature inside the test
apparatus [℃]

12.3

12.0

Pressure inside the test
apparatus [Pa]

502.1

15.5

Atmospheric pressure [hPa]1015.161015.1

Time

17:14:06

17:29:06

Measurement time

15 minSliding resistance

10 [ton] or less

Leakage test in the X (-12.5) direction

Temperature [°C]

While starting

Pressure [Pa]Item

*Since this is the direction in which the bellows
extend, it presents strict conditions wherein the
gap between the sliding flange and fixed flange
widens.
Measurement time (m)Atmosphericpressure [hPa]

Pressure inside the test
specimen (1)Pressure inside the test
specimen (2)Temperatureinside the factory

Temperature inside
the test specimen©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.121

2) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Verification of displacement traceability (spring type)]
After putting together the equipment, the sliding movement was verified just like it was verified in the case of the wedge typestructure. The leakage rate prior to sliding and after sliding were both under 0.045[m 3/h]. The sliding resistance was 9.6[kN] or less.
Sliding resistance was approx. 2[kN] when there is no thrust. Hence the sliding resistance due to thrust was approx. 7.6[kN]. The
surface pressure and the gap between the sliding flange and fixed flange was as given below.
After operating multiple times, the equipment was disassembled and re-assembled. At that time, no significant scratches were foundon the sliding surface.

Results of measuring the surface pressure and gap
Pressure scale (Cal)* Feeler gauge of 0.01 could not enter.

0.05
[mm]

0.01
[mm]

0.06
[mm]

0.03
[mm]

©International Research Institute for Nuclear DecommissioningNo.122

6. Implementation Items of This Project2) Development of technology for connecting heavy structures used for access and the confinement
structure for the connection parts[2] Confinement structure for the connection parts[Leakage test results (spring type)]A

As a result of the leakage test, it was found that the leakage rate was below the target leakage
rate of 0.12[m3/h] under all conditions. The sliding resistance was approx. 16.7[kN]( approx.
1.7[ton]) or less. Since the allowable sheer stress of welded part, welded with the equipment
hatch, is approx. 27[ton], the welded part does not break in the event of an earthquake and sliding
is possible. Also, leakage test was conducted after performing the operation multiple times, and it
was found that the leakage rate was below the target leakage rate.
Amount of displacement [mm]X
directionY
direction

θ

Testing
Pressure
[Pa]

1

0

0

－

500

0.043

2

+12.5

0

－

500

0.021

3

-12.5

0

－

500

0.061

4

0

+12.5

－

500

0.031

5

0

-12.5

－

500

0.03

No.

Leakagerate[m3/h]

Sleeve sideAZ(±0.2)
Y(±12.5)

X(±12.5)

PCV sideSurface to bepressed onθ(±0.54°)Standalone displacement absorption mechanism

6

+12.5

+12.5

－

500

0.027

7

+12.5

-12.5

－

500

0.023

8

-12.5

+12.5

－

500

0.063

9

-12.5

-12.5

－

500

0.064

10

－

－

+0.54

500

0.056

11

－

－

-0.54

500

0.053

Sealed surface(＋)

Y(±12.5)Sleeve side(－)

X(±12.5)

PCV side©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1232) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Leakage test results (spring type)]
The equipment was put assembled and the leakage test was conducted. The leakage rate was approx. 0.043[m 3/h] and thus
satisfied the target leakage rate of 0.12[m3/h].
[Test conditions] Spring type/without thermal spray/reference position
In the end

Temperature inside the test
apparatus [℃]

12.1

12.0

Pressure inside the test
apparatus [Pa]

519.6

177.5

Atmospheric pressure [hPa]1020.621020.8Time

19:35:04

19:50:04

Measurement time

15 minSliding resistance

2 [ton] or lessQ=

V𝑇20 𝑃2 𝑃1 V𝑇20 𝑃𝑎𝑡𝑚2 𝑃𝑎𝑡𝑚1−−[𝑃𝑎・ 𝐿Τ𝑠]
Δ𝑡 𝑇2 𝑇1 ＋ Δ𝑡
𝑇2
𝑇1

𝑞=

𝑄
[𝐿Τ𝑠]
101325

Leakage test at reference position (spring)Temperature [°C]

While starting

Pressure [Pa]Item

Measurement time (m)Here, the leakage rate (Pa・L/s) is in terms of Q: 20°C
P1: Gauge pressure (Pa) of the test specimen when measurement starts
P2: Gauge pressure (Pa) of the test specimen when measurement ends
Patm1: Atmospheric pressure (outside pressure) (Pa) whenmeasurement starts
Patm2: Atmospheric pressure (outside pressure) (Pa) after
measurement starts
Δt : Time from start of measurement to end of measurement (s)V: Internal volume (L) of the test specimen
Atmospheric
T20: Reference temperature 293 (K)pressure [hPa]T1: Absolute temperature (K) of the gas inside the test specimen whenmeasurement starts
T2: Absolute temperature (K) of the gas inside the test specimen whenmeasurement ends
q: Leakage rate (L/s) in terms of 20℃ and 1 atmospheric pressure

Pressure inside the test
specimen (1)Pressure inside the test
specimen (2)Temperatureinside the factory

Temperature inside
the test specimen©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1242) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Leakage test results (spring type)]
The equipment was clarified and the leakage test was conducted. The leakage rate was approx. 0.061[m 3/h] and thus satisfied
the target leakage rate of 0.12[m3/h].
[Test conditions] Spring type/without thermal spray/X-12.5[mm]In the end

Temperature inside the test
apparatus [℃]

12.3

12.0

Pressure inside the test
apparatus [Pa]

500.3

29.4

Atmospheric pressure [hPa]1020.321020.5

Time

19:14:46

19:29:46

Measurement time

15 minSliding resistance

2 [ton] or less

Leakage test at reference position (spring)Temperature [°C]

While starting

Pressure [Pa]Item

*Since this is the direction in which the bellows
extend, it presents strict conditions wherein the
gap between the sliding flange and fixed flange
widens.
Measurement time (m)Atmosphericpressure [hPa]

Pressure inside the test
specimen (1)Pressure inside the test
specimen (2)Temperatureinside the factory

Temperature inside
the test specimen©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1252) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Surface treatment]
With the purpose of enhancing sliding efficiency, tungsten carbide thermal spray was tried on the sliding flange. The sliding
flange was fabricated considering the impact of heat, etc. However, the sliding flange got majorly deformed due to the thermal
spray, and hence the leakage test could not be conducted.

[Dimension measurement results]+0.4(Opening)

-0.28

-0.36

Sliding flange (with thermal spray)

-0.12

+2.0

+0.11

0

(Opening)

+0.15
-0.2
0
* Additional work was performed after this measurement.

+0.7

+2.9

(Opening)

Sliding flange (without thermal spray)+0.7(Opening)

+2.5

+2.4

+1.6

©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1262) Development of technology for connecting heavy structures for accessing PCV and theconfinement structure for the connection parts[2] Confinement structure for the connection parts[Maintenance policy]
SUS is planned to be selected for all components of the displacement absorption mechanism. Also, none of the sections operate at all
times. Hence, it is assumed that maintenance is basically not required as long as it is not in a special environment, such as high temperature,high humidity, etc. Although regular maintenance is not deemed necessary, the approach towards maintenance including non-routine
maintenance is examined for each main part. Further, it is assumed that equipment other than this equipment will suffer massive damage if
there are any non-routine/unanticipated events.
Also, leakage detection needs to be verified for the entire system including the PCV. If leakage is suspected, the opening of the equipment
hatch is closed, and leakage is checked individually for the access tunnel (including the displacement absorption mechanism).
Components

Maintenance policy (regular)

Maintenance policy (non-routine/ unanticipated)

Even if there is corrosion, since it is assumed to progress
slowly, regular maintenance is not deemed necessary.

The connection part (welded part) connecting with the
PCV equipment hatch could be damaged first. If theconnection part is damaged, repair welding is
performed.

Around the bellows

Since there are no internal components, it is assumed thatmaintenance is not required.
It is assumed that connection parts can be dealt with using
metal O-ring, metal gasket, welding, etc.

The method of repairing the damaged bellows (rippedor broken) using adhesive is studied.
* The manufacturer recommends replacement.

Thrust mechanism(spring)

Nuts and bolts are used for adjustment and holding, but
double nuts, etc. are planned to be used to prevent
loosening. If adjustment / replacement is required due topermanent strain on the spring, adjustment/replacement isplanned to be performed by means of remote operation.

Replacement will be performed by means of remote
operation.

Thrust mechanism(wedge)Nuts and bolts are used for adjustment and holding, but
double nuts, etc. are planned to be used to prevent
loosening.

Replacement will be performed by means of remote
operation.

Fixed flange
Sliding flange©International Research Institute for Nuclear Decommissioning6. Implementation Items of This ProjectNo.1272) Development of technology for connecting heavy structures for accessing PCV andthe confinement structure for the connection parts[2] Confinement structure for the connection parts：Summary➢ The displacement absorption mechanism to be installed on the access tunnel and PCV
connection part was crystallized, and the wedge type structure and spring type structure
were studied for the sliding flange that absorbs the displacement in the horizontal direction(X axis) and vertical direction (Y axis). Element tests were conducted, and leakage rate,
amount of displacement and displacement traceability were verified.
➢ It was confirmed that sliding efficiency and leakage rate were satisfied using the spring typestructure described in No. 103.

➢ The issues related to the confinement structure for the connection parts were clarified basedon the results of the element tests.

©International Research Institute for Nuclear Decommissioning7. Summary

No.128(1) Development of an air-tight mechanism for large transfer containers➢ The air-tight mechanism of the lid part of large transfer containers required for transferringlarge structures, which have a function for preventing the spread of contamination and ashielding function against high radiation items stored in them, was studied. [Steps involved inoperating the dual lid for transferring structures were clarified, and issues at the time ofoperating the dual lid were identified.
➢ Items to be verified through element tests were identified from the issues when installing thedual lid, and element tests on the validity of the opening/closing mechanism of the dual lid andthe air-tightness performance were conducted. It was verified through element tests that thedual lid mechanism can work normally, and that the leakage rate satisfies the establishedleakage rate standard of 0.1 [vol%/ｈ] or less. Thus the feasibility was verified.
➢ Based on the above-mentioned test results, future challenges such as method of positioning
and inspecting the container, impact of the shape of the groove for O-ring on sealing
performance, sealed part maintenance method, etc., were clarified.
Studies will be continued under the Project for Development of Fuel Debris Retrieval Method.
➢ To ensure the safety of criticality of the large transfer containers used for collecting theunitized large structures to which fuel debris is adhered, the methods for preventing recriticality and for detecting criticality approach were studied. The criticality prevention
measure of injecting non-soluble neutron absorption material into the large transfer container
in advance was studied and the required amount of non-soluble neutron absorption material
under conservative conditions was evaluated.

©International Research Institute for Nuclear Decommissioning7. Summary

No.129(2) Development of technology for connecting heavy structures used for access and the confinement
structure for the connection parts[1] Development of technology for connecting heavy structures used for access➢ The slide part (stainless steel bearings and rubber bearings) used for delivering the access tunnel byrotating it was studied as a method for remotely connecting the access tunnel, which is a heavy structure,to the PCV. Element tests were conducted on each type of slide part using mock-ups simulating the actual
weight. The weight was changed and the possibility of delivery, the frictional resistance of the slide part andability of the slide part to follow were verified.
➢ In the case of stainless steel bearings, it was verified that 330[ton] can be delivered by means of rotation,
and while delivering 430[ton] as well, the frictional resistance was under the design value. While delivering
430[ton], rotation could not be completed till the end (0° to 45°) due to problems in the structure of the
jack. But delivery by means of rotation is expected to become possible by modifying the structure of thejack.
➢ As a result, the structure of the slide part showed in No.75 (stainless steel bearing material) is likely to be
used for delivery of the access tunnel.
➢ The issues related to the method of delivering (rotation) the access tunnel were clarified based on the
results of the element tests.
[2] Development of the confinement structure for the connection parts➢ The displacement absorption mechanism to be installed on the access tunnel and PCV connection part wascrystallized, and the wedge type structure and spring type structure were studied for the sliding flange thatabsorbs the displacement in the horizontal direction (X axis) and vertical direction (Y axis). Element tests
were conducted, leakage rate, amount of displacement and displacement traceability were verified.
➢ It was confirmed that sliding efficiency and leakage rate were satisfied using the spring type structure
described in No. 103.
➢ The issues related to the confinement structure for the connection parts were clarified based on the resultsof the element tests.
©International Research Institute for Nuclear Decommissioning8. Specific goals for achieving the purpose of the projectNo.130(1) Development of an air-tight mechanism forlarge transfer containers

To study large transfer containers used in the top access method as containers having the function of
preventing spread of contamination and the shielding function against high radiation items stored in them,and upon considering the pre-conditions for the large transfer containers and the required development
items, to verify the feasibility of the technology through element tests related to the air-tight structure of thelid part of the large transfer containers. And, to present a criticality control method for the period from aftercollection of the structures until they are stored.
(Target TRL* at completion: Level 3)(2) Development of technology for connecting
heavy structures used for access and theconfinement structure for the connection
parts[1] Technology for connecting heavy structures used for accessTo indicate the feasibility of the technology for remotely connecting heavy structures such as the newaccess equipment (access tunnel) to be installed in the R/B, while taking remote operation into
consideration for minimizing the dose of the workers, through element tests.
(Target TRL at completion: Level 3)[2] Confinement structure for the connection parts
To indicate the feasibility of the displacement absorption structure for the part connecting the accesstunnel and the existing structures such as PCV, etc., which absorbs the displacement in the event of anearthquake, while ensuring the confinement function, through element tests.
(Target TRL at completion: Level 4)

TRL level

Explanation

Phase

TRL7

Stage at which implementation is complete.

For practical use

TRL6

Stage at which field verification is conducted.

Field demonstration

TRL5

Stage at which a prototype is manufactured based on the actual equipment and verified in a simulated environment at the factory,
etc.

Simulated verification

TRL4

Stage at which function tests are implemented at the test manufacturing level as a development and engineering process.

TRL3

Stage at which development and engineering are being carried out by applying or combining past experiences. Or, stage at whichdevelopment and engineering are being carried out based on fundamental data in domains in which there is no prior experience.

Applied research

TRL2

Stage at which development and engineering are being carried out in domains in which there is almost no applicable priorexperience, and the required specifications are being defined.

Applied research

TRL1

Stage at which specific details pertaining to the development and engineering targets are clarified.

Basic research*TRL： Technology Readiness Level

Research for practical use©International Research Institute for Nuclear Decommissioning