DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTPROJECT OF DECOMMISSIONING, CONTAMINATED WATER AND
TREATED WATER MANAGEMENTDEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING ANDREMOVAL TECHNOLOGIESPUBLIC REPORT
October 2023

C1 - Interne

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTCONTENT OF THE PRESENTATION
Project Organization
A.
B.
C.
D.

III. TESTS FOR OPERABILITY ASSESSMENT

BACKGROUND & PURPOSE
GENERAL OVERVIEW OF THE PROJECTITEMS OF WORKSCHEDULE OF THE PROJECT

0.

Generalities

1.

Reachability tests

2.

Laser cutting tests with remote controled automated modes

3.

Synthesis of cutting tests :UPDATE with operability tests results

Technical PresentationI.

II.

INVESTIGATION

IV. IMPLEMENTATION STUDIES

0.

Generalities

0.

Generalities

1.

Input Data Analysis

1.

Dismantling of a CRD-H: methodology and basis

2.

Functional analysis (short synthesis)

2.

Assumptions about the carrier

3.

Assessment of cutting capabilities for various cutting tools

3.

General arrangement of the CRD-H dismantling scenario

4.

First development about the fall of object issue

4.

General features about HCU and CRD-H dismantling scenario

5.

Synthesis of investigations phase

5.

General features about grids dismantling

6.

General features about bar dismantling

7.

General features about ICM dismantling

8.

General features about rod dismantling

9.

General features about beams dismantling

ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER,
AWJ, LASER CUTTING)

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0.

Generalities

1.

Laser cutting tests

2.

Disk cutting tests

3.

Additional cutting tests with disk cutter

4.

Abrasive Water Jet cutting tests

5.

Synthesis of essential cutting tests

10. Dismantling scenario – Approach 2.1
11. Damaged equipments management
12. Operational time – Estimation of dismantling time & waste management

V.

Risks & Opportunities and GLOBAL SYNTHESIS OF THE PROJECT
1.

Risks and Opportunities

2.

Global synthesis of the project“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”2

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

A. BACKGROUND & PURPOSE
Why the project is needed?
CRD-H cutting and retrieval is a challenge to be addressed in the global scenario of Fukushima Daiichi damaged reactors decommissioning. Because conditions of CRD-H are deteriorated andbecause it is important to ensure that no fall of object can occur, these operations appear to be technically critical.
Therefore, R&D is needed to study the feasibility of a safe solution for the cutting & retrieval of CRD-H.
Usage of the project results:
The project results shall support the development of technologies contributing to the decommissionning of Fukushima Daiichi Nuclear
Power Plant. More specifically, the results of the project shall help in the implementation of a strategy for the safe removal of the CRDH on Units 1, 2 and 3.
.
Goal of the project:
The purpose of the project is to study Control Rod Drive Housing (CRD-H) cutting and the retrieval of the cut pieces. Three different
cutting techniques were already selected at the beginning of the project: disk cutter, laser cutting and Abrasive Water Jet (AWJ).
With the results of the essential tests and preliminary studies for the implementation on site, it is possible to start preliminary studies
for the design of a system that can cut and retrieve the CRD-H and avoid the fall of objects and work on a complete cutting andretrieval scenario.
The goal of this project is to secure the existence of one workable scenario, as safe and efficient as possible, to remove the CRD-H.
Irid : 平成30年度補正予算 廃炉・汚染水対策事業費補助金
技術研究組合 国際廃炉研究開発機構(IRID)「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」2020年度実施分最終報告、2021年08月

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

B. GENERAL OVERVIEW OF THE PROJECTGENERAL OVERVIEW OF THE PROJECT
Project content and progress have been determined in order to consider the whole operation of CRD-H removal. Here below the main steps (and their content) of the project are detailled:

INVESTIGATION
Content:• Determination of the input data of the project• Investigation of potential cutting techniques
and analysis of pros and cons
• Investigation of potential solutions in order toavoid potential fall of objects

Outcomes:• First assessment of cutting techniques
capabilities• First assessment of solutions in order to avoid
the fall of objects• Roadmap of the projects (cutting tests,
operability, study of implementation)

CONFIRM THE CHALLENGES
Content:• Essential cutting tests of CRD-H with laser
technique, AWJ and disk cutter• Essential cutting tests for the insertion of amechanical part in order to avoid the fall of
inner parts of CRD-H• First studies of implementation on site, firstscenario assessment

Outcomes:• Confirmation of cutting tools performance• Confirmation of performance of system toavoid the fall of inner parts of CRD-H• Preparationoftheoperability
tests(reachability of cutting tool on specific mockup, operability tests on specific mock-up withremote controled robotic arm

CONFIRM THE FEASIBILITY &CONCEPTUAL STUDIES
Content:• Reachability tests on specific mock-up inorder to verify that the cutting tool canreach all the elements to be cut• Operability tests with remote controled
robotic arm in order to verify that the cuts
are possible• Complete CRD-H retrieval scenario
considering results of tests and hypothesis
about the situation on site
Outcomes:• Confirmation of operability• Performance assessment on site (time ofoperations, waste management, etc.)

PROGRESS OF THE PROJECT
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

C. ITEMS OF WORKITEM 1 – INVESTIGATION (INPUT DATA & FUNCTIONAL ANALYSIS)• Verification that available input data is correclty used in the frame of the project. Functional analysis helps to determine the functions & constraints that the future system needs to comply with• First evaluation based on operational experience to determine which tool can be efficient for the different parts that compose a CRD-H. Indeed, a CRD-H is considered to be a complex systemthat includes several elements such HCU, hanging rods, etc. It has been considered that several tools may be needed for the whole CRD-H decommissioning operation
ITEM 2 – ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, ABRASIVE WATER JET, LASER CUTTING)• Essential cutting tests in order to assess cutting capabilities of Abrasive Water Jet cutting, Disk cutting and Laser cutting
ITEM 3 – SYSTEM TO AVOID THE FALL OF OBJECTSOne of the major issues that has been highlighted is the potential fall of an object during the cutting and retrieval of CRD-H operations. Therefore, item 3 of work has been implemented so it waspossible to:• Determine and evaluate preliminary solutions to avoid the fall of object. It concerns the inner parts of the CRD-H as well as bigger parts of CRD-H• Carry out essential tests to assess the efficiency of studied solutions (for the fall of inner parts of CRD-H only)• Carry out preliminary studies in order to find a solution in a case of a fall of a « big » object (such as a whole CRD-H for instance)
ITEM 4 – OPERABILITY TESTS
Another major issue is the capability for the cutting tools to access the different parts to be cut. This is especially true for the external parts of the CRD-H that are close to the pedestal wall.
Therefore, this item of work covered:• Studies for the implementation of cutting tools in order to ensure in which conditions it is possible to implement the cutting tools• Essential tests on a specific mock-up in order to ensure the capability of a laser cutting tool to reach every element of the CRD-H• Operability & cutting tests in order to ensure that laser cutting is possible for every elements that compose the CRD-H with remote controled means. System to avoid the fall of inner parts has
also been tested during this campaign
ITEM 5 – IMPLEMENTATION STUDIES
Following the results of the different studies and tests carried out in items 1 to 4, implementation studies have been carried out. They cover:• Complete scenario of intervention, including downgraded situation management• Assessment of implementation times for the whole CRD-H decommissioning scenario
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

D. SCHEDULE OF THE PROJECT
2022

05

06

07

08

09

10

11

12

2023
01

02

03

04

05

Item 1 - Investigation
INPUT DATA
F. ANALYSISVALIDATION OF
INPUT DATAPRELIMINARY STUDIES

Item 2 – Assessment of cutting capabilities for various cutting tools
DESIGN OF CRD-H
MOCK-UPMANUFACTURING OF CRD-H MOCK-UPTESTS PROGRAMS FOR CUTTING TESTS(LASER, DISK CUTTING, AWJ)ESSENTIAL CUTTING TESTS ON CRD-H (LASER)
ESSENTIAL CUTTING TESTS ON CRD-H (AWJ)
ESSENTIAL CUTTING TESTS ON CRD-H (DISK CUTTER)TESTS REPORTS

Item 3 – System to avoid the fall of objects
PRELIMINARY STUDIES OF IMPLEMENTATION AND STUDIES ON THE FALL OF OBJECTS

Item 4 – Operability tests
DESIGN OF VESSEL’S BOTTOM MOCK-UPS
MANUFACTURING OF VESSEL’S BOTTOM MOCK-UPS
REACHABILITY TESTS WITHLASERLASER CUTTING TESTS WITH LASER

Item 5 – Implementation studies (conceptual studies)C1 - Interne“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 0.

GENERALITIESAt the very beginning of the project, it is important to gather all the necessary information that will be useful for the completion of the project. Input data that are needed concern:• CRD-H characteristics: materials, geometry (diameters (outer, inner, inner parts), list of components…)• CRD-H area characteristics: surroundings (HCU (Hydraulic Control Unit), isolating plate, rods, bars, etc.)• CRD-H environment: access, openings, overall geometry, pedestal conditions (water level, known state of CRD-H and vessel’s bottom), etc.
These input are helpful to design a solution that could be suitable for the implementation on site. Indeed, not only it is needed to determine which cutting tool is capable of cutting a CRD-H, it isalso mandatory to assess the conditions of intervention.
Following pages synthetize the input data that have been used for the completion of the project.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 1.

INPUT DATA ANALYSIS

In this section of the report, we intend to synthetize the work that has been achieved in order to determine the applicable input data that have used for the whole project. Input data concern thegeometry of each units, the conditions that are known on site, etc.
DATA CONCERNING THE OVERALL GEOMETRY OF PEDESTAL THAT HAVE BEEN CONSIDERED
3 different units reactors

Openings➢ Unit 1 is 13% smaller than Units 2 and 3➢ An opening (1 980 x 770 mm) with a ramp that lets a 1000mm opening height➢ Presence of Fuel Debris in the bottom of the pedestal➢ 4 openings (1 000 x 760 mm) for pipes HCU (diameter of each HCU : 25-30mm)➢ Presence of a cooling shower system operationnal on site (water runoff from the RPV)
➢ The access platform to the CRD-H is destroyed and evacuated

HCU opening

Completetank
CRD-H and theirsupports

Fuel Debris
Main opening

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 1.

INPUT DATA ANALYSIS

CRD-H AND NEARBY ELEMENTS➢ The structure bearing CRD-H is made, from top to bottom, of : insulating plate (limit of the study scope), beam, hanger rod, a grid and support bar (each dimension has been estimated)

Insulatingplate➢ 97 CRD-H for unit 1 and 137 CRD-H for units 2 and 3➢ Length from the bottom of the beam to the top of the grid: 2 500 mm➢ The CRD-H are welded from vessel’s bottom, in suspension.

➢ External diameter: 152-159 mm➢ Some CRD-H may contain Fuel Debris, and/or water but not under pressure➢ Layer thickness: 13-18 mm for the most external one➢ Some CRD-H may have been damaged, even missing (if missing, out of study scope)➢ The cutting starts from the bottom➢ Material housing: 304L stainless steel

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 1.

INPUT DATA ANALYSIS

CRD-H AND NEARBY ELEMENTS➢ Each CRD-H has 2 HCU, probably loaded with fluids (water, contaminated water, etc.) but not under pressure➢ The inner parts of the CRD-H are considered present, so the most restrictive case is considered

Retracted
position

Tokyo Electric Power Company Holdings,
Inc.,Unit 3 Primary Containment VesselInternal Investigatio,November 30, 2017

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 2.

FUNCTIONAL ANALYSIS (SHORT SYNTHESIS)REQUIREMENTS:

CHALLENGES:➢ Earthquake: during the operations, equipment in place must not damage thepedestal barrier and the operations must stop in a safe situation➢ Positioning of the cutting tool in a extremely narrow environment➢ Positioning of the system for the removal of the cut piece➢ Positioning of the system to avoid the fall of the inner parts of the CRD-H➢ Cutting of the CRD-H, a multiple layer item, potentially filled with Fuel Debris, with alimited cutting strength➢ Holding in position the inner parts of the CRD-H➢ Saving a fallen part to fall at the bottom of the pedestal in the Corium➢ Keeping safety barrier upstanding during an earthquake➢ Fall prevention: locally (avoiding the fall of inner parts of the CRD-H) and globally(catching up a part of a too highly damaged CRD-H, away from the CRD-H currently
being dismantled)
Local fall of objects issue
1

2

Cutting line

1. First cut of the
CRD-H (cuttingline)
2. When the first
cut piece isremoved, innerparts of the
CRD-H may fall

Global fall of object issue
1

2

1. The left side
CRD-H vibrates
during cutting

Vibration
During cutting

2. Vibrations aretransmitted tothe extremly
damaged CRD-H,
and a part of it
falls

VesselCRD-H partiallydismantled

CRD-H extremly
damagedFall of inner part

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Removal of
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 3.

ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS

Cutting a CRD-H for its retrieval not only concerns the CRD-H itself alone. In order to remove a CRD-H, it is mandatory to also consider the HCU and other surrounding elements (such as plates,
grid, rod, bars, etc.).
Several cutting techniques have been considered in a first step in order to assess their capabilities depending the element to be cut that is considered. Their capabilities have been assessedconsidering criteria given in the next page.
LIST OF CUTTING EQUIPMENT CONSIDEREDLASERDISK CUTTER

AWJ

SHEAR

SABER SAW

BAND SAW

Designed for the decommissioning of
nuclear power plants, the Laser
cutting head ELC-A (CEA) canwithstand extremely severe working
conditions.
An additional collection head underdevelopment allows the collection of
airborne particles that are produced
during the cutting operations.

The disc cutter is a simple solution to
implement. Its size depends on thedisc to be used and the power to beprovided. A motor creates therotation of a disc that cuts byabrasion. The depth of cut depends
on the diameter of the disc. The discis a replaceable element.

The abrasive water jet is a powerfultool for cutting and drilling. This
process is enhanced by adding an
abrasive to the working fluid to speed
up the cutting of hard steels

A shear can be used to cut and reduce
metal parts very quickly. It is a water
hydraulic system. Its cutting capacity
depends on its size.

The sabre saw is a dismantling toolwith an interchangeable straight
blade. It allows a cold and slow
cutting.
The control of the cutting geometry is
not precise, but is sufficient fordismantling. The blade is a
replaceable element (1 cut per blade).

The band saw is a slow and cold
continuous band cutting tool. It is apneumatically powered tool.
For this tool developed by ONET, thecutting capacity is 100 mm x 100 mm.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 3.

ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLSCOMPARISON – POSSIBILITIES OF USE AND CAPABILITIES OF EACH TOOLS DEPENDING THE ELEMENT TO BE CUT THAT IS CONSIDERED
This table shows the results of the studies carried out on our different cutting equipment solutions. They are rated according to the different criteria explained in the previous page as well as theircompatibility with the elements that make up the environment: CRD-Hs, HCUs and support structures.

Best

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fit

CRD-H

HCU

Othersstructures

Ability to cut ...

Laser

Yes

Yes

Yes

Disk cutter

Yes

Yes

Yes

AWJ

Yes

Yes

Yes

Shear

No

Yes

Yes

Saber saw

No

Yes

Yes

Band saw

No

Yes

Yes

Goog
fit

Compatibility
with adamaged
CRD-H

Mediumfit

Waste
production

Radioactivity
dispersion

Additional firerisk

Environment
accessibility

Operability“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Maintenance

Safety mode

Not
Acceptable

OPEX (OPerating
EXpense)13

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 3.

ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS

Main conclusions of the preliminary studies for the assessment of cutting capabilities for various cutting tools are the following:• As the table shows, it is necessary to consider not only the cutting capacity, but also various criteria such as operability, remote maintenance, waste production, etc. to fully assess the capabilitiesof each cutting tool
• Each tool has benefits and weak points• Only laser cutting, AWJ and disk cutting techniques are suitable to completely dismantled a CRD-H (i.e. cutting the CRD-H itself, but also the surrounding parts)• Other mechanical tools can be interesting for the cutting of a limited items that surround the CRD-H• However, one major benefit of AWJ and laser cutting is precisely that they are mechanical cutting tools which ease the issues of blockage and maintenanceFor the next steps of the project, only the disk cutting, the AWJ and the laser cutting techniques have been considered

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 4.

FIRST DEVELOPMENT ABOUT THE FALL OF OBJECT ISSUE

As it is explained in §1.2 of this document, one issue of CRD-H cutting will be the fall of inner parts if there is any left. Therefore, it has been investigated several solutions to block the inner parts of
the CRD-H or to mitigate the risk of fall.

LIST OF SOLUTIONS TO PREVENT THE FALL OF INNER PARTS OF THE CRD-H

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PIN

HALF-PLATEWELDINGRESIN INJECTION

BUCKET

The pin inserted in a hole drilled will
prevent falling event of inner tubes orother large pieces inside the CRD -H.

Inserting metal plate/net in order toprevent fall off cut-out inner CRD-H
elements or other inside the CRD-H
foreign materials.

This tool can be equipped directly on
an arm or manipulated by a clamp.
Such tools are already in use on the
Marcoule nuclear research center.

Injection of resin or other expanding
material through the opening willsecure inner tubes/parts and if
available any foreign material inside
the CRD-H housing prior cutting
procedure.

Placed under the CDR-H during the
cutting or evacuating operations
would prevent fall of cut out
elements or fuel debris, internal
CRD-H
elements
ormeltingcompositions.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 4.

FIRST DEVELOPMENT ABOUT THE FALL OF OBJECT ISSUECOMPARISON (SOLUTIONS TO PREVENT THE FALL OF INNER PARTS OF THE CRD-H)
This table shows the results the studies carried out on our different solutions to prevent the fall of inner parts of the CRD-H. These are rated according to different criteria as well as their installation
and use requirements: whether they require cutting or drilling on the CRD-H.

Best

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fitPartialcutting

Drilling

Requires anintervention
…

Pin

No

Yes

Half-Plate

Yes

No

Welding

Yes

No

Resin
injection

Yes

No

Bucket

No

No

Goog
fit

Mediumfit

Compatibility
with a damaged
CRD-H

Waste
management

Risk of fall ofinternal
elements in the
CRD-H

Radioactivity
dispersion

Check that thesolution iseffective

OPEX

These two solutions have beentested on later stages of the
project“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Not
Acceptable

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 4.

FIRST DEVELOPMENT ABOUT THE FALL OF OBJECT ISSUE

Main conclusions of the preliminary studies for the assessment of preventing fall of internal parts of CRD-H are the following:• The pin seems effective and needs to be tested• The half-plate seems effective and needs to be tested• These solutions can be completed by the bucket

For the next steps of the project, tests have been carried out to confirm the feasibility to put in place pin or plate solution.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 4.
FIRST DEVELOPMENT ABOUT THE FALL OF OBJECT ISSUE
LIST OF SOLUTIONS TO PREVENT THE FALL OF GLOBAL OBJECTSThe following solutions are those selected by Onet Technologies following various studies on the global fall prevention problem.
Among these solutions, the majority are platform solutions. These platforms remain concepts, they have a similar design but are equipped with different frames.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 4.

FIRST DEVELOPMENT ABOUT THE FALL OF OBJECT ISSUECOMPARISON BETWEEN SOLUTIONS TO PREVENTTHE FALL OF OBJECTS (GLOBAL)
As for the local solution for the prevention of the fall of the innerparts of the CRD-H, the table gives the notation of the different
solutions listed in the previous page.

Size of retained
elements

Resistance tofalling elements

Complexity of
installation

Impact on thepedestal

ClutterComplexity of
dismantling

Permissible
additional load

Platform fixed
Platform
extended
Platformsuspend HCU
Platformsuspend ROD

Concept to be studied
In a further step

Floating
platform
Platform heldat PCV

Concept to be studied
In a further step

Shockabsorbing
layer

FishnetBest

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fit

Goog
fit

Mediumfit“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Not
Acceptable

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 4.

FIRST DEVELOPMENT ABOUT THE FALL OF OBJECT ISSUESYNTHESIS OF THE ANALYSIS: SOLUTIONS TO PREVENT GLOBAL FALL
The various studies have led to various solutions for the fall of global objects. The recommended fall arrest systems, those with the best results in the comparative analysis, are the floating platform
and the shock absorption layer.

FLOATING PLATFORMSHOCK-ABSORBING LAYER

Assembly of the tiles (laid on the material layer)

Floating support assembly on water

Filling the bottom of the pedestal

Filling the bottom of the pedestal with water

These solutions are the most suitable according to Onet Technologies CN. They can hold elements of all sizes, resist repeated dropping of elements, are easily installed and maintained/dismantled,
have little impact on the pedestal and will not interfere with the dismantling system.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

I. INVESTIGATION
1. 5.

SYNTHESIS OF INVESTIGATIONS PHASE

Our different studies have led to different conclusions regarding the use of cutting tools and solutions to prevent the cut objects from falling. Each solution requires associated tests, such as cutting
or drilling a CRD-H mock-up.
SOLUTIONS TO PREVENT THE FALL OF INNER PARTS OF THE
CUTTING EQUIPMENT COMPARISON : TEST PROGRAMLASERDISK CUTTERAWJC1 - Interne

CRD-H : TEST PROGRAM

The three tools initially
identified (laser, disk cutter
and abrasive water jet) got
no inadmissibility rating andcan be compared on the 4criteria "compatibility with adamaged CRD-H, waste
management, environment
accessibility, and OPEX", by
the intermediary of a firstseries of tests, as identical as
possible, on an elementarymodel.
Depending on the results,
they may possibly be
supplemented by overall
tests to better estimate
criteria such as accessibility,
operability and degradedmodes.

PIN

HALF-PLATE

BUCKET

The prevent fall systems chosen at
this stage are the pin and the halfplate.
These two systems require apreliminary operation of drillingor half-cutting before theirinstallation.
These operations will be tested on
basic CRD-H models, to checktheir operability.
The bucket is an additional
prevent fall system, that will be
implemented in different phasesof the scenario, to improve theefficiency

SOLUTIONS TO PREVENT THE FALL OF GLOBAL OBJETCS

Given the damaged state of several CRD-H, to guarantee theabsence of falling parts on to the Fuel Debris, in addition to a
local solution, it is necessary to consider a global solution of
the platform type.

SHOCK-ABSORBING LAYER“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

FLOATING PLATFORM

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 0.

GENERALITIESThis phase of the project aimed at assessing the capabilities of the three identified cutting tools. More specifically, cutting performances (cutting efficiency in various conditions, cutting time, etc.)
have been monitored. Cutting tests have been carried out on a simplified mock-up of CRD-H.
Cutting tests have been carried out on industrial cutting tools with optimized cutting parameters: it is thenpossible to determine the capability of a cutting tool. If the cutting test is not conclusive in lab conditions, then it
is possible to conclude that the cutting tool will not be suitable for an implementation on site.
In this phase of tests, solutions for the blockage of inner parts have also been tested.
A

A

Laser cutting tests

Disk cutting tests

AWJ cutting tests• Essential cutting tests invarious conditions to assess
cutting performances andlimits• Essential cutting tests invarious conditions to assess
cutting performances andlimits• Essential cutting tests invarious conditions to assess
cutting performances andlimits• Essential drilling tests withlaser in order to assess thefeasibility for the insertion of apin (blockage of inner parts)
Control Rod Drive Housing andinside parts mock-up (A-A cut)

• Essential drilling tests withAWJ in order to assess thefeasibility for the insertion of apin (blockage of inner parts)

Picture of the mock-up of CRD-H for
performance assessment of cutting
tools

Evaluation of cutting performances and limits for each tools and first conclusions about the possibility of use on site

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 1.

LASER CUTTING TESTS

Tests carried out in CELENA Facility in CEA’s premises at Saclay from
September to October 2022
MOCK-UP frame

Robotic arm

Objectives of the tests:• Confirm the feasibility of CRD-H cutting with laser cutting• Confirm the feasibility of drilling a tube with laser for the insertion ofa pin (to avoid fall of inner parts of CRD-H)

MOCK-UP

Laser head

Experimental Means:• Laser source with a maximum output power of 8 kW
• A linear motion table XYZ: BALTHAZAR• A robotic arm: KUKA
• Cutting head: straight air-cooled head
• Pressurized air – 6 bar• Four Mock-ups :▪ M1: 5 concentric cylinders (from C1 to C5)▪ M2: 4 concentric cylinders + a central rod (from C1 to C4 + R)
▪ M3: 2 cylinders C1 + C5
▪ M4: cylinder C1 + central rod R + fused cast zirconia (ZrO2) gravel• Mock-up mounted on a frame

CELENA FACILITY – CEA Saclay

C1 - Interne

C1

C2

C2

C3

C3

R

C5

C4

C4

ZrO2
gravelR

C5

Mock-up M1

C1

C1

C1

Mock-up M2“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Mock-up M3

Mock-up M4

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 1.

LASER CUTTING TESTSTest program – divided in 4 steps
1.1 Feasibility tests with 8 kW laser power• Objective : cut through a maximum diameter of a mock-up• Tests were carried out on four mock-ups having the following characteristics:▪ M1: 5 concentric cylinders ( Diameter (D) ~ 168 mm and effective thickness (T) ~ 60 mm))
▪ M2: 4 concentric cylinders + a central rod, D ~ 168 mm and T ~ 100 mm)▪ M3: 2 cylinders C1 + C5 (D ~ 168 mm and T ~ 64 mm)▪ M4: cylinder C1 + central rod R + pieces of fused cast zirconia ( D ~ 168 mm and T < 168 mm)
1.2 Tolerance assessment• Parameter: only the variation of laser head – mock-up position was tested. Angle cut was not possible for the maximum available output power.
• Tests were performed on mock-up M1 with the robotic arm

1.3 Essential tests for preventing the fall of objects (pin or plate insertion to block the CRD-H’s inner parts)
I. Laser piercing
Goal : pierce a hole of 1 cm diameter for the full diameter of the mock-up▪ Tests performed on mock-ups : M1 and M2▪ Three configurations were tested – variable laser head – mock-up position, multi point piercing and spiral trajectory cutting
II. Cut through the half diameter
Goal : widen the laser kerf’s width to insert a plate▪ Tests performed on mock-ups : M1 and M2▪ Two configurations were tested
1.4 Laser cutting tests on mock-up which simulates a damaged CRD-H
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 1.

LASER CUTTING TESTSSteps 1&2: Feasibility tests with 8 kW laser power and tolerance assessment

Test conditions :Laser head

Laser beam

Rectilinear motion• Laser output power: 8 kW
• Variable cutting speed• The cutting head was moved following a rectilinear motion
using a KUKA robotic arm• The cut was stop once the mock-up completely separated• Test were carried out on four mock-ups : M1, M2, M3 and M4

After cutting

During cutting
Mock-up M1

Effective thickness: 60 mm
Cutting : succeed

Mock-up M2

Effective thickness: 100 mm
Cutting : succeed

Mock-up M3

Effective thickness: 64.2 mm
Cutting : succeed

Mock-up M4

Effective thickness: 168 mm
Cutting : succeed• All four mock-ups were successfully cut with 8kW laser power. There was no need to test smaller diameter mock-ups, as laser cutting was successful for the mock-ups full diameter.
• For M1, the cutting process was assessed for laser head – mock-up position. Slightly different values of the cutting speed were obtained for 10 and 20 mm positions.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 1.

LASER CUTTING TESTS

Step 3: Essential tests for preventing the fall of objects (pin insertion to block the CRD-H’s inner parts)

P6

Test conditions :• Laser output power: 8 kW
• Pressurized air: 6 bar• The cutting head was moved using a KUKA robotic arm
following either a rectilinear or a circular trajectory• Five kind of tests were performed on two mock-ups : M1
and M2

Mock-up M1
Laser beamLaser head

P5
Mock-up

P4
Test

MotionDIN (mm)

P1

Static piercing

3

P2

Static piercing

4

P3

Piercing - rectilinear step back of the laser head

9

Cutting using circular trajectories

8+ rectilinear step back of the laser head + static
piercing

8

P5

Multi-point piercing

~ 10

P6

Multi-point piercing

~ 10

P4

C1 - Interne

Mock-up M1
P3
P2

P1
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTS• Set-up:

Disk cutter

A mock-up of CRD-H with 5 tubes of different diameter and thickness was designed for laser/disk cutter/AWJ cutting tests. For the disc
tests, the largest diameter tube (168.3 mm) is not used because the equipment does not allow it. The feasibility of cutting by disc cutter
is tested on a simpler configuration.

CRD-H clamps

The cutting of the CRD-H is done with an automatic disc cutter installed in a containment airlock. The machine allows to adapt therotation speed of the disc, the cutting speed and the cutting angle.
The CRD-H mock-up will be clamped onto the cutting table. The cutting movement will be mainly linear but tests with an angle can bedone.

CRD-H mock-up• Test program:
The test program is divided in 2 steps, a first step which will allow to define the optimal cutting conditions for a simple configuration anda second step where the CRD-H will be cut in several observable configurations on site (2 fixations, 1 fixation or with an angle).
For each cutting, the criteria analyzed are the following:❑ Possibility of cutting❑ Status of the disk ( wear, breakage...)❑ Observation of a vibration on the disc and on the CRD-H

Parameters of cutting:• Disk cutter: up to 1380 rpm• Cutting speed: 60 to 1100 cm/min• Cutting angle: 0 to 45°
Disk 350 mm or
450 mmC1 - Interne

Type of tests

Objectives

Disk
configuration

Numberof clamps

Cutting parameters

Number of
cutting

Definition of thesettings

Definition of the most accurate cutting
parameters

Linear2

Variable cutting androtation speeds(2 to 3 speeds tested)

6(depending on
the results)

Linear cutting withdouble fixation

Check the cut with a linear approach on a
fixed CRD-H (1st cut)Linear2

Fixed cutting and rotation
speeds1

Linear cutting withsimple fixation

Check the cut with a linear approach on a
CRD-H already cut or incorrectly fixedLinear1

Fixed cutting and rotation
speeds1

Linear cutting half adiameter

Check the cut with a linear approach on a
CRD-H partially cut

Linear1

Fixed cutting androtation speeds

1Angular cutting withdouble fixation

Check the cut with an angular approach on Angulara fixed CRD-H
(30°)

2

Fixed cutting and rotation
speeds1“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

1st step
Definition of
cutting
parameters
2nd step27

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTSBEHAVIOR OF THE INTERNAL TUBES AND ROLE OF THE HOLDING PINS WITH A KNOWN 350MM METAL DISKThe test conditions were:Ø141.3mm – thickness 6.55mm✓ Linear cutting angle (0°)✓ Use of a CRD-H mock-up with a maximum outside diameter of 141.3mm✓ Use of a metal diamond disk 350 mm (because we have experience with this disk)

Ø114.3mm – thickness 6.02mm
Ø88.9mm – thickness 5.49mm
Ø48.3mm – thickness 5.08mm

1. Impact of the means of fixation
These tests are performed with a fixed rotation speed (1380 rpm) and a fixed cutting speed (90 cm/min).
Test 1: 2 clamps + 1 vertical pin + 2 horizontal pins

Test 2: 2 clamps + 2 vertical pins + 1 horizontal pin

Test 3: 2 clamps + 1 vertical pin (near) + 1 horizontal pin

Vertical pin

Horizontal
pin

Horizontal
pin

Horizontal
pins

Verticalpins

Vertical pin
near thecutting zone

High vibration and blocking the disk at the end of the cutting process
Test 4: 2 clamps + 1 vertical pin (far) + 1 horizontal pin

Test 5: 1 clamp + 1 vertical pin (near) + 1 horizontal pin

Horizontal
pin

HorizontalpinVertical pin
far the cuttingzone

Vertical pin
near thecutting zone

High vibration and blocking the disk at the end of the cutting process
C1 - Interne

Successful cutting

Successful cutting“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Successful cutting

In order to ensure that the disk is cut
without blocking, the following fixing
parameters should be used:• mounting of 1 or 2 clamps to hold the
CRD-H in position• Positioning of a pin near the cut andperpendicular to the cutting direction to
avoid displacement of the internal tubes

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTS

Final status - speed cutting (test 6)

BEHAVIOR OF INTERNAL TUBES AND ROLE OF CUTTING SPEED AND ROTATION SPEED
2. Impact of the cutting speed
These tests are performed with the optimal fixation means defined in step 1 (2 clamps + 2 vertical pins + 1 horizontal pin) and a fixed rotation
speed (1380 rpm).
→ 2 cutting speeds are tested: 90 cm/min (minimal speed of the grinder) and 170 cm/min
Test

Speed cutting (cm/min)

Results

6

90

Successful cutting

7170

Blocking of the disk after 7s → disk cutter stops automatically to protect the motorization

3. Impact of the rotation speed
These tests are performed with the optimal fixation means defined in step 1 (2 clamps + 2 vertical pins + 1 horizontal pin) and the speed cutting
defined in step 2 (90 cm/min).
→ 4 rotation speeds are tested: 1380 rpm(maximal speed of the grinder) / 1200 rpm / 1000 rpm / 800 rpm

Test 8

Test

Rotation speed

Results

Test 981380 rpm

Successful cutting

Test 1091200 rpm

Successful cutting

Test 11101000 rpm

Successful cutting

11

800 rpm

Successful cutting

The decrease in speed increases the duration of the cutting time which implies a higher heating of the disk and a faster wear. It ispreferable to use the speed of 1380 rpm.
C1 - Interne

Final status - rotation cutting“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

The cutting slots show higher temperaturemarks as the rotation speed decreases.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTS

Diamond disk DSL MAXX D 450 mm

BEHAVIOR OF THE INTERNAL PARTS WITH A DIAMOND DISK OF 450MM
Cutting test of tubular CRD-H in the optimal condition
These tests are performed with the optimal parameters defined previously:• Fixation with 2 clamps and 2 vertical pins + 1 horizontal pin• Cutting speed: 90 cm/min• Rotation speed: 1380 rpm
The test conditions were identical to the parameter test conditions. Only the cutting disk is different with a 450 mm
diameter disk being used to allow the cutting of the CRD-H in one pass:✓ Linear cutting angle (0°)✓ Use of a CRD-H mock-up with 3 pipes (141.3 mm / 114.3 mm / 88.9 mm) and a bar (48.3 mm)✓ Use of a disk D 450 mm with diamond teeth

Test

Conditions

Cutting
speed

Rotation speed

Cutting length

Results

1

Air

90
cm/min1380 rpm

141.3 mm

Successful cutting

2

Water
cooling

90
cm/min1380 rpm

70 mm

Cutting half of the CRD-H in 21 min→ Fast wear of the disk

Air

90
cm/min1380 rpm

3

C1 - Interne

10 mmVery slow cutting --> the disk isdamagedThe CRD-H can be cut in one pass with a secure
fixation but the disk seems to degrade quickly.
The CRD-H cuttings in tests 2 and 3 could not becompleted because the disk was too damaged.
The disk allows only one complete cut.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTSBEHAVIOR OF THE INTERNAL PARTS WITH A SAW BLADES OF 355MM
Cutting test of tubular CRD-H in the optimal condition
These tests are performed with the following parameters:• Fixation with 2 clamps and 2 vertical pins + 1 horizontal pin• Cutting speed: 90 cm/min• Rotation speed: 1380 rpm

DRYTECH Saw
Blades 355/90T

The test conditions were identical to the parameter test conditions. Only the cutting disk is different with a 450 mm diameter disk
being used to allow the cutting of the CRD-H in one pass:✓ Linear cutting angle (0°)✓ Use of a CRD-H mock-up with 4 pipes (141.3 mm / 114.3 mm / 88.9 mm) and a bar (48.3 mm)✓ Use of a saw blades D 355 mm with tungsten carbide teeth
Test

Conditions

Cutting
speed

Rotation speed

Cutting length

Results

1

Air

90
cm/min1380 rpm

141.3 mm

Successful cutting

2

Air

90
cm/min1380 rpm

85 mm

Cutting half of the CRD-H → Fast
wear of the disk

The CRD-H can be cut in one pass with a secure fixation but the disk seems to degrade quickly:• increased cutting time on the 2nd cutting• early wear of the disc with the breakage of several teeth
With the saw blade, there seems to be a higher stress on the CRD-H mock-up. This stress slightly displaces the CRD-H
during the cutting process, which leads to a blocking of the disc and a wear of the teeth.
C1 - Interne“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Complete cutting intest 1

Early wear of the
disc

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTS

Initial status

INFLUENCE OF A CENTRAL ROD ON THE CUTTING
Cutting test of CRD-H with a central rod
These tests are performed with the following parameters:• Fixation with 1 clamp and 1 vertical pin far the cutting zone + 1 horizontal pin• Cutting speed: 90 cm/min• Rotation speed: 1380 rpm• Linear cutting angle (0°)• Use of the Diamond disk D 450 mm
The CRD-H mock-up includes 3 tubes (141.3 mm / 114.3 mm / 88.9 mm) and a central bar of 48.3 mm.
Test

Conditions

Cutting speed

Rotation speed

Cutting length

Results4

Water
cooling

90 cm/min

1380 rpm

141.3 mm

2 blockages of the disk:• 1 after cutting the central rod• 1 after cutting the 114.3 mm tube

Blocking at
the centralbar

C1 - Interne

A disk cutter will not cut assemblies that
include moving components.
In order to allow a cutting without blocking, itis necessary to position pins and clamps near
the cutting zone.

Blocking at
pipe
114.3 mm

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTS

Initial status

CUTTING FEASIBILITY IN CASE OF DIFFICULTY IN POSITIONING THE CUTTING TOOL
Angular cutting test of CRD-H
These tests are performed with the following parameters:• Cutting speed: 90 cm/min• Rotation speed: 1380 rpm• Linear cutting angle (30°)• Use of a metal diamond disk 350 mm
The CRD-H mock-up includes 4 tubes (141.3 mm / 114.3 mm / 88.9 mm / 48.3 mm).
Test

FixationsCutting
speed

Rotation speed

Cutting length

Results

1

1 clamp+1 vertical pin (near the
cutting zone)
1 horizontal pin

90 cm/min

1380 rpm

141.3 mm

Successful
cutting2

1 clamp+1 horizontal pin

90 cm/min

1380 rpm

141.3 mm

Successful
cutting

Final status

Cutting the CRD-H at an angle is possible with cutting results similar to linear cutting test.
The cutting forces are identical for linear and angular cutting.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 2.

DISK CUTTING TESTSSYNTHESIS - DISK CUTTING TESTCRD-H CONFIGURATION:
The cutting results obtained depending on the configuration of the CRD-H are:•Cutting achieved❑ CRD-H mock-up includes 4 stainless steel pipes (141.3 mm / 114.3 mm / 88.9 mm / 48.3 mm)•
Cutting not achieved (blockage of the disk)❑ CRD-H mock-up includes 3 stainless steel pipes (141.3 mm / 114.3 mm / 88.9 mm) and a central rod (48.3 mm)
FIXATION:
To achieve optimal cutting without blocking the disk, it is necessary to have a good clamping of the CRD-H which limits the displacement of the internal elements (clamps and pin near
the cutting zone).
CUTTING PARAMETERS:•Limitation of the cutting speed to prevent the disk from blocking.
•The speed of rotation has no significant impact on the cutting process. A higher speed decreases the cutting time and the temperature rise.
DISK TYPE:
Three types of disks were tested:• Metal diamond disk 350 mm → Cutting completed without blocking for all configurations but only on half of the mock-up (h=80mm) / Normal wear of the disk
• Disk D 450 mm with diamond teeth❑ Cutting completed without blocking for configuration with 4 pipes (Full height cutting) / Fast disk wear
❑ Blocking of the disk with the configuration 3 pipes and a central rod• Special stainless steel saw blade of 350 mm → Cutting completed but a fast wear of the blade and an important stress on the CRD-H with a risk of blocking if an element is moved(CRD-H fixation to be adapted)
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 3.

ADDITIONAL CUTTING TESTS WITH DISK CUTTERCUTTING TEST WITH A SPECIFIC TREATMENT BLADE (in order to improve cutting performances):
This test leads to the same conclusion as previous tests :- Blockage during cutting- Fast wear of the disk

Possible Disk implementation
in a low part of the pedestal

Disk before cutting

Disk after cutting

DRILLING TEST WITH MECHANICAL DRILL :Drilling was successful, but with Important vibrations during drilling. Regarding the strenght appliedon the CRD-H cylinder, it seems impossible to use this technology on a damaged CRD-H

Impossible Disk implementation
in a high part of the pedestal

Disk implementation along the CRD-H
Conclusion :Disk system 450mm is too big to be set in place in many cutting configurations. Blockage risk is
too high to keep disk cutting technology for CRD-H. There is no need to perform more tests.
This is why only laser test will be carried done in CEA Marcoule.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 4.

ABRASIVE WATER JET CUTTING TESTS• Set-up:
The cutting tests are carried out in the OMAX facilities (specialist in water jet cutting) on a MAXIEM industrial machine.
The tests are performed on CRD-H mock-ups composed of 5 pipes (168.3 mm / 141.3 mm / 114.3 mm / 88.9 mm / 48.3 mm) or 4 pipes (168.3 mm / 141.3 mm / 114.3 mm / 88.9 mm) and 1 central rod 48.3 mm.
Water pressure pump

CRD-H mock-up

Control panel

Cutting machine
MAXIEM•Test program:
Test

Type of tests

Parameters to be observed

1Linear cutting of 4 concentric stainless steel tubes

2

Linear cutting of 1 concentric stainless steel tubes + central rod

3

Angular Cutting of 4 concentric stainless steel tubes

4

Drilling of 4 concentric stainless steel + central rod

•
•
•
•
•

C1 - Interne

Speed cutting
Abrasive consumption
Concentric tubes behaviour during cutting,Pin behaviour during cutting,
Cut quality/feasibility“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”36

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 4.

ABRASIVE WATER JET CUTTING TESTS

Non-emerging cutting

SET CUTTING PARAMETERS
The test conditions were:• Linear cutting angle (0°)• Use of a CRD-H mock-up with 5 pipes (168.3 mm / 141.3 mm / 114.3 mm / 88.9 mm / 48.3 mm)• Fixation with 2 clamps and 1 vertical pin + 1 horizontal pin➢ Definition of the cutting speed
The variable parameter to enable waterjet cutting is the cutting speed. The water pressure and abrasive flow rate
are defined by the supplier based on the equipment and feedback:• Water pressure: 3000 bar• Water flow rate: 3.2 L/min• Abrasive flow rate: 320 g/min (abrasive GMA Garnet – mesh 120)
Results:

Emerging cutting
Test

Speed cutting (mm/min)

Results

1

23

Impossible to cut → non-emerging jet

2

7.75

Impossible to cut → non-emerging jet

3

4.40

Successful cutting

The optimal cutting speed is below 4.40 mm/min.
Note: The placement of the holding pins and clamps had no effect on the cut.
Also, the waterjet near the pin did not degrade the fixation, only a slight sanding of the pin is visible.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 4.

ABRASIVE WATER JET CUTTING TESTSCUTTING TESTS IN DIFFERENT CONFIGURATION
The test conditions were:

Partial cutting
Test 2

Emerging cutting
Test 3

Emerging cutting
Test 4

Partial cutting
Test 5• Fixation with 2 clamps and 1 vertical pin + 1 horizontal pin• Water flow rate: 3.2 L/min• Abrasive flow rate: 320 g/min (abrasive GMA Garnet – mesh 120)
Results:
Test

CRD-H mock-up

Cutting angle

Speed cutting(mm/min)Abrasive quantity(kg)

Results

1

5 pipes(168.3/141.3/114.3/88.9/48.3mm)

Linear (0°)

4.40

12.24

Successful cutting

2

4 pipes (168.3/141.3/114.3/88.9mm)
1 central rod 48.3mm

Linear (0°)

4.40

12.24

Partial cutting in thecentral zone

3

4 pipes (168.3/141.3/114.3/88.9mm)
1 central rod 48.3mm

Linear (0°)

2.75

19.58

Successful cutting

4

1 pipe 168.3mm
1 central rod 48.3mm

Linear (0°)

2.75

19.58

Successful cutting

5

4 pipes (168.3/141.3/114.3/88.9mm)
1 central rod 48.3mm

Angular (30°)

2.70

24.30

Partial cutting in thecentral zone

Speed
reduction

In all the cases studied, the cuts are completed or partially completed. For the partial cuts, the decrease of the cutting speed allows torealize a complete cut. CRD-H cutting is allowed but with a slow cutting speed and a high consumption of abrasive (≈ 20kg per cut).
Note: Waterjet cutting without abrasive is not possible.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 4.

ABRASIVE WATER JET CUTTING TESTSHOLE CUTTING TESTSObjective:
Drill a 15 mm diameter hole to allow the insertion of a pin.
With a fixed position, the high-pressure water jet can make a hole with a diameter of 0.8 mm. To make a 15 mm diameter hole, the nozzle must be
rotated (see figure on the right, position 1: starting point / position 2: end point).
Initial status

Intermediate status

The test conditions were:• Fixation with 2 clamps and 1 vertical pin + 1 horizontal pin• Water flow rate: 3.2 L/min• Abrasive flow rate: 320 g/min (abrasive GMA Garnet – mesh 120)

Results:
Test

CRD-H mock-up

Cutting angle

Abrasive quantity(kg)

Results

1

4 pipes (168.3/141.3/114.3/88.9mm)
1 central rod 48.3mm

Linear (0°)

17.15

Successful cutting

Final status (Top view)

Final status (Bottom view)The drilling of a hole by waterjet is possible but requires a precise remote operation to allow the rotation in a circle of
15 mm of the cutting nozzle.
On the front side, the cut is precise but at the exit, slight deformation appears because of the dispersion of thewaterjet.
In addition, as with cutting, drilling requires a large quantity of abrasive (≈ 17kg per hole).
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

II. ASSESSMENT OF CUTTING CAPABILITIES FOR VARIOUS CUTTING TOOLS (DISK CUTTER, AWJ, LASER CUTTING)
2. 5.

SYNTHESIS OF ESSENTIAL CUTTING TESTSCRITERIA : test result

LASER 8 kWDISK CUTTER 450 mm

ABRASIVE WATER JET

OPEX : cutting duration

Cutting : succeed
On a 5 cylinders mock-up

Cutting : succeed
On a 4 cylinders mock-up

Cutting : succeed
On a 5 cylinders mock-up

Environment accessibility : feasibility of angular cut

Not feasible due to lack of power oflaser source

Feasible

FeasibleWill be tested again during operability
tests with 14 kW laser source
Waste management : mass of induced waste percut

Non significant

Wear of disk even with carbide
treatment~20 kg of abrasive/cut

Prevent fall : drilling duration

Cutting : succeed
To be tested with 14kW

Cutting : succeed
But with huge vibrations

Cutting : succeed

Main conclusions of the essential cutting tests can be summarized as following:• The cutting of a CRD-H with disk cutter is possible only if the inner parts are blocked. If they are not, the cutting is barely possible because of the disk blockage. In any case, disks wear out
very quickly which will lead to frequent disk changes on site. Furthermore, it shall be to implement a 450 mm diameter disk on site
 The disk cutter solution is abandoned at this point for the next steps of the project• It is possible to cut efficiently a complete CRD-H with a laser cutting head. However, complete feasibility needs to be proven with the 14 kW laser head
• AWJ tests are conclusive, even if the cutting time is higher than the laser cutting time. However, AWJ produces a lot a secondary waste and presents a difficulty of implementation in somecases
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3. 0.

GENERALITIESFollowing the essential cutting tests, it is mandatory to evaluate the capacity of the chosen tools to be implemented on site and perform the cutting operation. Two main items need to be covered:• The capacity of a given tool to reach the cutting positions => “Reachability tests” with representative mock-up of cutting tool, pedestal & CRD-H environment and robotic arm are needed• The capacity of a given tool to be used with a robotic arm and perform the actual cutting operations => “Operability tests” with representative mock-up of CRD-H environment are needed. Entire
cutting scenario can be tested

Tests have been carried out with laser cutting technique only
PHASE 1 – REACHABILITY TESTSPHASE 2 – OPERABILITY TESTS

Tests are carried out with a mock-up of a laser cutting head mounted on a robotic arm. A
representative mock-up (in terms of geometry) of CRD-H environment is used

Tests are carried out with a 14 kW laser source + laser cutting head mounted onto arobotic arm. Representative mock-up of CRD-H environment is used (geometry + materials)

What is evaluated during this phase of tests?

What is evaluated during this phase of tests?

Ability for the laser cutting head to reach every cutting area with the help of
a robotic arm in a representative environment

Ability for the laser cutting head to reach every cutting area with the help of arobotic arm in a representative environment. (Robotic arm does not allow it in thisconfiguration)

Actual cutting operations

Actual cutting operations: whole cutting scenario is carried out

Operability assessment with remote controled operations

Operability assessment with remote controled operations

These two phases of tests cover the entire verification of the possibility of operation on site
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3. 1.

REACHABILITY TESTSObjective:
To verify in remote operation the accessibilities and possibilities of cutting of all the components of the CRD-H. The tests were carried out on a full scale with a KUKA KR16 remote-controlled arm.
The test conditions were:• Full scale mock-up of the CRD-H• KUKA KR16 robotic arm• 3D printing laser head (curved head 8 kW and linear head 14 kW)

Robotic arm KUKA withcurved head

Robotic arm KUKA withlinear head

Results:
Accessibilities were carried out according to the dismantling scenario
The remote operation tests have shown that:• All operations are achievable with the curved head
• The removal of the elements close to the wall of the enclosure and the access X6 are notachievable with the linear head but the other elements are then accessible with the linear head.
Curved laser head OK

Linear laser head /wall contact

Way of removal
Robot arm access via X6

In red are presented the elements not accessible
with the linear laser headC1 - Interne

Enclosure wall

“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Full scale mock-up CRD-H

Robotic arm KUKA

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3. 2.

LASER CUTTING TESTS WITH REMOTE CONTROLED AUTOMATED MODES• BOTTOM VESSEL LASER CUTTING – EXPERIMENTAL SETUP

Cutting cell set-up (Configuration 1 of the bottom vessel CRD-H mock-up)

Tests carried out in HERA facility at CEA Marcoulefrom January to April 2023,

Experimental means:✓ Laser source with a maximum power of 14 kW✓ Laser cutting head : straight air-cooled head
✓ Pressurized air : 6 bar✓ 2 PTZ camera✓ Maestro robotic arm:
▪ 6-axis robotic arm▪ Max payload: 60 kg / Max reach: ~1.5 m▪ 2 control modes: remote controlled withforce feedback and Robotic/automatic

Maestro robotic arm
Mock-up

VESSEL BOTTOM PART

2 mock-up configuration:
Laser head

Graphite wall

25 cm

Configuration 1
C1 - Interne“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Configuration 2

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3. 2.

LASER CUTTING TESTS WITH REMOTE CONTROLED AUTOMATED MODES• BOTTOM VESSEL LASER CUTTING – TEST PROGRAM (1/2)✓ Test ID 1 : Cut the
HCU in front of the
CRD-H✓ Test ID 5 : Cutting of the
CRD-H just above the topof the flange✓ Test ID 2 : Pierce a 10
mm diameter hole in a
CRD-H and insert the
pin-type fall prevention
system in teleportation✓ Test ID 6 : Cutting out thedifferent configurationsof CRD-H: A, B, C, D
✓ High thickness up to 141mm✓ Test ID 3 : Partial cut of
CRD-H (half diameter)and set up the platetype fall prevention
system in teleportation.

✓ Test ID 7 : Cutting of thegrid and grid clamp andgripping test of elements
in remote operation.

✓ Test ID 4 : Cutting of
the CRD-H bottom
flange25 cm

Configuration 1 of the bottom vessel CRD-H mock-up
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3. 2.

LASER CUTTING TESTS WITH REMOTE CONTROLED AUTOMATED MODES• BOTTOM VESSEL LASER CUTTING – TEST PROGRAM (2/2)

Specific tests:✓ Test ID 8 : Cuttingof a support bar.

✓ Test ID 10 : Cuttingwith a 15° angle a
CRD-H (configurationA)✓ Thickness of 143 mm✓ Test ID 11 : Cutting of an ICM (InCore Monitor) tube (Solid rod, 56
mm diameter) with laser at 150
mm distance.

✓ Test ID 9 : Cuttingof hanger rod.

✓ Test ID 12 : Cutting of a HCU tube
filled with water. The pressure in
the tube is measured with amanometer.

✓ Test ID 13 : Cutting of 35 mm steel plate at distances up to
500 mm.
Configuration 2 of the bottom vessel CRD-H mock-up
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3. 2.

LASER CUTTING TESTS WITH REMOTE CONTROLED AUTOMATED MODES• BOTTOM VESSEL LASER CUTTING – RESULTS OF THE CRD-H CUTS
Ø152 mm – thickness 15 mm
Ø112 mm – thickness 16 mm
Ø79,5 mm – thickness 11,5 mm
Ø56 mm – thickness 14 mm✓ 4 configurations of CRD-H
according to the presence or
not of internal components.
✓ All CRD-H configurations
could be cut with a 14 kW
laser.

CRD-H configuration A

CRD-H configuration

10 cm

A

B

C

D

138

115

141

118

Representation of the
cutting profile overlaid on
the corresponding CRD-H
tube assembly

Cutting of CRD-H configuration A withflangeC1 - Interne

Cutting a section of the CRD-H
configuration B

Max thickness (mm)“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”46

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TECHNICAL PROGRESS• BOTTOM VESSEL LASER CUTTING – FALL PREVENTION SYSTEM TEST RESULTS• HCU CUTTING RESULTS

Pierce and PIN insertion method✓ Obj. : Laser drilling of a hole in the middle of CRD-H ;insert a PIN device into the hole
✓ Piercing Drilling : succeed✓ Hole profile : Ø 13 mm at the entrance, Ø 9 mm at
the exit✓ PIN (Ø 8 mm) implementation in teleportation
validated

Create a slot and PLATE insertion method✓ Obj. : create a slot on half of the CRD-H; insert a
PLATE device into the slot

Setting up the pin-type fall prevention systemin teleportation✓ Obj1 : remove the HCU to allow access to the CRD-H✓ at normal distance (30 mm, 4 kW) / conf. 1 of themockup : succeed✓ at longer distance (100 mm, 4 kW) / conf. 2 of themockup : succeed✓ at the maximum distance tested (830 mm, 14 kW) :succeed✓ Obj2 : Draining the CRD-H if water is present ->Cutting of HCU filled with water✓ Measure the pressure inside the tube during cutting-> max 423 mbar at 4 kW

✓ cutting (at 14 kW) : several round trips to remove
adherent slag into the kerf
✓ Slot thickness : 3 mm
✓ PLATE (2 mm thick)
implementation in
teleportation validated

Plate fall prevention system in place in the CRD-H
C1 - Interne“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

HCU filled with water and instrumented during cutting47

DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TECHNICAL PROGRESS• BOTTOM VESSEL LASER CUTTING – FLANGE CUTTING TEST RESULTS✓ Obj.: lighten the flange before separating it from the CRD-H✓ Cutting as close as possible to the top part of the flange ->Ø150 mm at 14 kW / ~ 11 kg removed✓ The cut in the upper flange diameter is too thick (Ø250mm) to be done with a 14 kW laser✓ Lateral cutting of the upper part of the flange (185 mm
max. thickness) at 14 kW / ~ 2 kg removed✓ After separating the flange from the CRD-H, the lightened
flange assembly weighs ~ 39 kg• GRID CUTTING RESULTS✓ Obj.: remove the grid
✓ Several strategies tested:• Cut the grid in 2 parts at once (2 plates at the sametime) at 8 kW : succeed• Recover the whole grid assembly without cutting it• Separate the 2 grid plates by cutting the holding screw
through the first plate : drill and cut at 14 kW : succeed✓ The different elements of the last 2 strategies wererecovered with a teleoperated clamp• SUPPORT BAR AND HANGER ROD CUTTING RESULTS✓ Support bar cut at 14 kW for a thickness ~ 50 mm: succeed✓ Hanger rod cut at a distance of 300 mm(accessibility constraint) at 14 kW: succeed
C1 - InterneLong distance cutting test

Flange cutting plan

Cutting of the bottom flange part

Cutting of the support bar

Cutting of the grid part
Left: cut in 2 part
Right: release the grid clamp

Remote gripping operation on the grid

“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Cutting of the hanger rod

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORTIII. TESTS FOR OPERABILITY ASSESSMENT
3.3.

SYNTHESIS OF CUTTING TESTS : UPDATE with operability tests results

CRITERIA : test result

LASER 14 kW

LASER 8 kWDISK CUTTER 450 mm

ABRASIVE WATER JET

OPEX : cutting duration

Cutting time : 7-15 min

Cutting time : 17 min

Cutting time : 11 min

Cutting time : 38 min

Environment accessibility :feasibility of angular cut

FeasibleNot feasible due to lack of
power of laser source

Feasible

Feasible
But many difficulties tomanage the abrasive jar

Waste management : mass of
induced waste per cut

Non significant

Non significant

Wear of disk

~20 kg of abrasive/cut

Prevent fall : drilling duration

Cutting time :6,5 min/hole

Cutting time : 16 min/hole

Cutting time with a drill :6 min/hole
But with huge vibrations

Cutting time : 17 min/hole

New

New
Main conclusions of the operational cutting tests can be summarized as following:• AWJ tests are conclusive, even if the cutting time is higher than the laser cutting time. However, AWJ produces a lot a secondary waste, and presents a huge difficulty to manage the abrasive
jar, that has to be fulfilled approximately after each cut• The laser 14 kW reaches every requirements of the cutting functions and thus, is the tool proposed in the cutting scenario.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4. 0.

GENERALITIES

Implementation studies are carried out with regards of the tests results, operational experience, available input data and assumptions about the conditions of site. The goal of these studies is todetermine in which conditions, under which scenario, it will be possible to dismantle the entire CRD-H elements.

Implementation studies cover:• Feasibility of a cutting & removal of CRD-H scenario: the idea is to determine, step by step, how it is possible to implement the cutting tools, how it is possible to retrieve every cut pieces while
ensuring that the risk of a fall of object is minimized. The scenario considers the different cutting operations, the change of tool if needed, the operations of retrieval, etc.
• Determination of operational time: according to the tests results (cutting performances) and with consideration for the determined scenario, it is then possible to evaluate the operational times
on site (implementation time, cutting time, retrieval time, maintenance, etc.)

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.1

DISMANTLING OF CRD-H: METHODOLOGY AND BASIS

The dismantling scenario of CRD-H is based on these principles:

Methodology:

Analysis of constraints and assumptions:• Prioritizing the removal of CRD-H before the GRID support structure• Dismantling equipment must be able to enter through access X-6• Minimizing the presence of dismantled equipment above the remotely
operated tools in order to limit the risk of the tool jamming in the pedestal• Limiting the risk of equipment falling for each of the elements being
dismantled• Implementing the laser aspiration head as soon as possible to limit the riskof spreading contamination• Dismantling of CRD-H will start with CRD-H closest to X-6 in order to getbetter acces• The maximum amount of space must be freed up as soon as possible nearX-6 in order to limit the presence of equipment to be dismantled above theremotely operated tools

Lexical definition for agood understanting of
the scenario : CRD-H LINE
and CRD-H ROW:

Row: set of CRD-H locatedperpendicular to the GRID supports
between two rows of tie rods,

Line: GRID supports
and located between
two of them.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.1

DISMANTLING OF CRD-H: METHODOLOGY AND BASIS

Legend : Starting aera for the dismantling of CRD-H

Approach 2: from one side

Definition of possible attackzones for CRD-H dismantling

2.1 : on one side between the GRID supports andhanging rods

Explanation page 53

Approach 1: from below: The approach and installation of
the tools as well as the dismantling is carried out frombelow the CRD-H.

Explanation page 54

Explanation page 54

Approach 2: from one side

2.2 : by one side facing the GRID support andhanging rods

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.1

DISMANTLING OF CRD-H: METHODOLOGY AND BASIS

Justification for keeping or not an approach : Approach 1 from below the grid and CRD-H
By considering a dismantling approach from below the CRD-H, the first equipment encountered is in the order of the plans:•

Plan 1: the support structure: support bar, GRID, lower part of the hanging rods•

Plan 2: lower end of the ICMs, end of the HCUs, flange of the CRD-H.

Support Bar
HangingrodeFindings:•

The CRDs are not directly accessible and are located above the support elements•

The support elements are the first elements accessible for removal by starting the dismantling from below.

•

The space available between the various components of the CRDs and in particular between the GRIDs and the support bar is restrictive for the installation oftools and robotic arms.

With the aim of meeting the need to maintain the support structure for as long as possible :•The objective is to dismantle CRDs and other items such as ICMs in the first place•

Remove the elements of the support structure in a second step.

Grid
Grid Clamp
HCU

Considering the need to prioritize the dismantling of the CRDs before the support
elements, here is an example of the scenario of the laser cutting tool:

The placement of the removal tools is compromised given thespace available. The same goes for the evacuation of the cut
elements, it is not possible to evacuate them through the support
structure.
Major drawback identified: poor accessibility of the CRDs without removing
the support elements beforehand. It is impossible to maintain the support
structure before removing the CRD-H as part of approach 1.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.1

DISMANTLING OF CRD-H: METHODOLOGY AND BASIS

Justification for keeping or not an approach : Approach 2.1 and 2.2
Approach 2.1 : Parallel to the support BARS and between the hanging rods-

Maximum space available between support bars and hanging
rods to reach CRD-H-

Access to the CRD-H for cutting without prior access to support
bars, hanging rods or GRID is possible-

Different axes of progress are identified for the dismantling of
CRD-H:

View in the axis of the support bars-

Row/row-

Line/line

The approach by the axis parallel to the support BAR is retainedand developed according to two approaches:•

CRD-H dismantling row by row•

CRD-H dismantling line by line

Approach 2.2: Dismantling of CRD-Hs perpendicular to the support bar-

Presence of SUPPORT BARS and hanging rods in the axis ofprogression-

Impossibility of progressing without removing the supports bars
as dismantling progresses

Major drawback identified: poor accessibility of the CRDs without
removing the support elements beforehand. It is impossible tomaintain the support structure before removing the CRD-Hs as partof approach 2.2.

Perpendicular view to support bars
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.2
ASSUMPTIONS ABOUT THE CARRIER
Hypothesis

Entrance in the pedestal

The scenario needs a carrier that answers to specific hypothesis:

In order to operate into the pedestal, the carrier needs to follow some steps priorly. (The number of arms
on the carrier is not relevant in the example below)• Able to go in and out of the pedestal• Able to reach every elements inside the pedestal• Resistance to falling objects

1

4

2

5

6

• Includes into the structure the storage
of MUC (Mitigating Unit Can)• Able to carry arm + tool + weight• Accurate and stable• Needs to be horizontal
In order to reach the top elements of thepedestal, a lifting column is necessary on
the carrier.
This system needs the carrier to be
perfectly horizontal in order to rise thecolumn vertically.

Lifting column

6

3

6

[1] The carrier enters into the PCV[2] The carrier is totally set in the runners[3] The carrier is moved to be set horizontally[4] The carrier moves inside the pedestal, it is now possible tospread the arm[5] The lifting column can rise vertically[6] The carrier can go deeper inside the pedestal to reach elements

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.3

GENERAL ARRANGEMENT OF THE CRD-H DISMANTLING SCENARIOFree up space to allow optimal
deployment of the remotely
operated arm and tools
Minimize the presence ofelements being dismantled above
the remotely opeated arms during
operations

Details in platforms pages

N°18-19

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.3

C1 - Interne

GENERAL ARRANGEMENT OF THE CRD-H DISMANTLING SCENARIO“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.3

GENERAL ARRANGEMENT OF THE CRD-H DISMANTLING SCENARIO

Freeing up space for remotely operated tool deployement

Dismantling of CRD-H obstructing/overhanging the deployment of the remotely operated arm(s)-Free up space to allow optimal deployment of the remotely operated arm and tools
Minimize the presence of elements being dismantled above the remotely operated arms during operations
Enable the deployment of remotely operated equipment upwards for the dismantling of CRD-H-

By simulating deployment of a possible remotely operated arm in the 3D model produced by ONET of the pedestal and CRD-H:
Some CRD-H as well as the associated support structures interfere with optimal deployment
These CRD-H are shown in the images below
Simulation of deployment of the remotely operated arm and identification of CRD-H obstructing or overhanging its operation

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.3

GENERAL ARRANGEMENT OF THE CRD-H DISMANTLING SCENARIO

Freeing up space for remotely operated tool deployement-

allow the deployment of the two remotely arms configuration and tools-

By simulating deployment of a possible remotely operated
arm in the 3D model produced by ONET of the pedestal and
CRD-H
Conclusion : at least, the first two lines of CRD-H(depending of design of the 2 remote arms) need
to be removed with the single arm configuration.

CRD-H in red to be cut with one arm configuration
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.4

GENERAL FEATURES ABOUT HCU AND CRD-H DISMANTLING SCENARIO
Global dismantling method:
HCUs exit in
the pedestal

HCU horizontalparts• Phase 1 : dismantling of the front andback of the vertical part of the row• Phase 2 : dismantling horizontal part of
the HCU higher in the piedestal

Initial state: All front and back HCUs arepresent

Initial state: Only the HCU horizontal parts
remainSet a clips up all along the HCUs of the row

Set the cutting tool: special wrench pinch

Set the cutting laser tool up on the arm

Dismantling of the HCU horizontal parts

Cutting front and back HCUs between clips
HCUs

CRD-H

ICM

Set the wrench tool up on the arm

Global dismantling method:
HCU are dismantled from bottom to top.

Dismantling is possible either with one or
two robotic arms.
A special clip system is used to prevent
HCU parts from falling

C1 - Interne

All HCU parts of the row are dismantled

Clips system

Dismantling tool : Wrench with the shear
tool holding a HCU
In order to hold
HCUs, clips are
set on the CRD-H
of the row withthe wrench toolon the arm

Remove and drop off each part of the HCUs
inside the MUC
All HCU front and back vertical part areremoved

Dismantling tool: Curved laser headequiped with dust collection head.
“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Set clips on the
HCUs

Setting clips along
HCUs

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT
Phase 1

IV. IMPLEMENTATION STUDIES
4.4

GENERAL FEATURES ABOUT HCU AND CRD-H DISMANTLING SCENARIO

Global dismantling method:

CRD-H’s of the row to be dismantled

They are dismantled in different phases from
Phase 1bottom to top.

Dismantling the flange bottom parts

Phase 1: bottom of the flange -> lower flange Phase 2
mass for next step

Half cutting or drilling of CRD-H

Phase 2 and 3: prevent from falling system are put Phase 3
in place by cutting or drilling the CRD-H in
Phase 4different places to prepare phase 5

Set fall-arrest system

Phase 4: Flange is dismantled. A special prevent Phase 5
fall system is put in place on the grid, rest of theflange is cut off from the rest of the CRD-H
Phase 5: the rest of the CRD-H is cut from bottom
to top in several pieces.

Dismantling of the flange

Phase 3
Recovery bucket

Recovery bucket heldby grid supports

Plate and plate inserted in a CRD-H

Pin

Phase 4

Flange support

CRD-H of the row are dismantled

CRD-H bucket• Cutting tool : curved head with aspiration

Platform• Wrench tool to put in place prevent fall systemand evacuated cut parts.

C1 - Interne

Phase 5

Dismantling of the CRD-H top parts

Several changes of configurations and tools areneeded to perform the scenario with one roboticarm.

• Combine equipment to cut CRD-H core(wrench + laser cutting tool)

Phase 2

Alternative
prevent fall system
Curved laser head withspecific collection head

Straight laser head
combined with gripper tool

Example of wrench tool

“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Carrier with therecoveryplatform

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.5

GENERAL FEATURES ABOUT GRIDS DISMANTLING

Global dismantling method:
The grid is cut in multiple parts. A specificprevent fall system can be set before cutting.
Phase 1: Set of the special prevent fall system(bucket)Phase 2: Cutting the grid in different parts
Recovery bucket

Phase 3: Recovery of the cut parts in thebucket with a wrench tool.
Several changes of configurations is necessary
to perform the scenario with one robotic arm.

Overview of the GRID

• Cutting tool : curved head
Platform• Wrench tool to put in place prevent fallsystem and evacuate cut parts.

Alternative
prevent fall system
Line of cut preview

C1 - Interne“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Carrier with therecoveryplatform

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IV. IMPLEMENTATION STUDIES
4.6

GENERAL FEATURES ABOUT BAR DISMANTLING

Global dismantling method:
As for the grid, support bar is cut in multiple
parts. A specific prevent fall system is set on
the carrier (recovery platform).
Phase 1: Set cutting tool and recovery platform
Phase 2: Cutting the support bar in different
parts
Phase 3: Recovery of the cut parts on therecovery platform with a wrench tool.

Several changes of configurations is necessary
to perform the scenario with one robotic arm.

Cutting the support bar with the curved laser tool on
the arm and the recovery platform on the carrier• Cutting tool : curved head
• Wrench tool to put in place prevent fallsystem and evacuate cut parts.
Order of cutting:• Step 1:• Step 2:
Recovery platform

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IV. IMPLEMENTATION STUDIES
4.7

GENERAL FEATURES ABOUT ICM DISMANTLING

Global dismantling method:
The ICM is cut in parts from bottom to top.
The cut at a distance with the straight laser
cutting head.

ICM to be dismantled

Set the wrench tool on the arm

The bottom part is cut and fall in a recovery
bucket.
The other part are cut and fall in a cylindricalbucket that is directly on the robotic arm
combined with the cutting head.

Several changes of configurations is necessary
to perform the scenario with one robotic arm.

Set the recovery bucket bellow
the ICMCut each part of the ICM anddrop it off in MUC

Cylindrical bucket withthe linear laser tool

Recovery bucket

Set the wrench tool on the arm
Set the laser tool on the arm• Cutting tool : linear laser cutting head
• Wrench tool to put in place prevent fallsystem and evacuate cut parts.

Cut the three first parts of the
ICM

Grab each piece of ICM fromthe recovery bucket to drop it
off in MUC

Set the laser with the cylindricalbucket on the arm

ICM is dismantled• Cylindrical bucket to prevent from falling,C1 - Interne“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Cutting of ICM with therecovery bucket

Cutting of the ICM
with the cylindricalbucket on the arm

64DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.8

GENERAL FEATURES ABOUT ROD DISMANTLING

Dismantling scenario
Global dismantling method:
The rod is cut in parts from bottom to top.
They are cut with the curved laser headequipped with aspiration to limit dispersion.
The recovery platform for the falling part is set
on the carrier for the bottom part.
The other part are cut and fall in a cylindricalbucket that is directly on the robotic arm
combined with the cutting head.
Several changes of configurations is necessary
to perform the scenario with one robotic arm.
• Cutting tool : curved laser cutting head
• Wrench tool to evacuate cut parts.

Rods to be removed
Set the curved laser tool and theplatform on the carrier
Cut the rods of the row just over the
support bar
Set the wrench tool on the arm
Remove each pieces from theplatform and drop them off in a MUC

Curved laser tool withplatform on carrier

Wrench tool to remove
pieces from the platform

Set the curved laser tool with thecylindrical bucket on the arm• Cylindrical bucket to prevent from falling
Cut each rod of the row
All rods of the row are removed
Curved laser tool + cylindrical bucket on the arm
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.9

GENERAL FEATURES ABOUT BEAMS DISMANTLING

Global dismantling method :The beam is cut in place in parts from top tobottom to reduce the global mass. The cut parts
are sufficiently little to be moved by the arms. Parts
are recovered by two specific recovery systems(angle bracket and recovery bucket)
As the beam is reduced in size, the bottom part left
in place is then sustained with a specific prevent fallsystem (angle bracket) set on the next direct
parallel beam.
As the prevent fall system maintains the bottom
part of the beam, it is possible to cut and evacuate
the rest of the beam.

Cutting top parts of the beam

The beams are dismantled from the center beam toedge beams.

Cuttingbottom partof the beam

Several changes of configurations is necessary to
perform the scenario with one robotic arm.

• Cutting tool : curved laser cutting head
• Wrench tool to evacuate cut parts• Angle bracket and recovery bucket to prevent
fall of parts

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.9

GENERAL FEATURES ABOUT BEAMS DISMANTLING

Initial state

Cutting and dismantling of central beams
Cutting the top partof the beamMoving from beam to beam

Dismantling of edge beams
Cutting the beam struts
and the rod struts

All beams are removed
Cutting the bottomof the beamMoving angle brackets
on the next beamOnce the first beam is dismantled, we move each angle bracket to the next beam to hold the beamthat was previously held.
There is two situations to chose the first beam:• In the first situation, if beams are not damaged due to the Fuel Debris, it is possible to start by one of the edge beams and dismantle beams one by one from this beam (see first situation below)
and at the end of the process, only one edge beam remain.

• In the second situation, if beams are damaged, it will probably on the middle beams. Therefore, it is better to start the dismantling of beams by the middle (see second situation below) in orderto remove the maximum of beams and do not left a beam in the middle. At the end of this situation, two edge beams remain (see next page to these beams).

First situation: the dismantling starts with a edge beam and one beam remains at the end

Second situation: central beams are damaged, therefore, the dismantling starts in the middle. Two beams remain at the end
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H row by row
1-Initial State

C1 - Interne-

Free up space as you cut CRD-H
Cut out the visible CRD-H before removing the associated support elements
Limit the presence of equipment being dismantled above the remotely operated tools

2-Removal of CRD-H and troublesome equipment

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H row by row
Reminder: 3-Withdrawal of the first rank of CRD-H

C1 - Interne

4-Removal of the first row of GRID+support bars+hanging rods

“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

5-Withdrawal of the second rank of CRD-H

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IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H row by row
Reminder: 5-Withdrawal of the second rank of CRD-H

C1 - Interne

6-Removal of the second row of GRID+support bars+hanging rods

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7-Withdrawal of third rank from CRD-H

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IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

The dismantling operations are repeated until the complete
removal of the CRD-H

Details of dismantling the CRD-H row by row
Reminder: 7-Withdrawal of third rank from CRD-H

8-Removal of third row from GRID+Support bars+hanging rods

Dismantling row by row
Front HCU cutout of the entire row
Rear HCU cutout of the entire row
CRD-H cutout of the entire row
Cutout of GRID of the entire row
Hanging rods cuttout of the entire row
Support bars cuttout of the entire row

ICM cuttout of the entire next row
Next row

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H line by line

1-Initial State

C1 - Interne-

Delay the removal of the support bars as late as possible
Free up space as you cut CRD-H
Cuts out the visible CRD-H before removing the associated support elements
Limit the presence of equipment being dismantled above the remotely operated tools

2-Removal of CRD-H and troublesome equipment(Idem stage 1 to 4 scenario row by row)

“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

3-Withdrawal of the first line of CRD-H

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H line by line
Reminder: 3-Withdrawal of the first line of CRD-H

C1 - Interne

4-Removal of the second line

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5-Removal of the free line of support bars

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IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H line by line
Reminder: 5-Removal of the free line support bars

C1 - Interne

6-removal of next line of CRD-H“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

7-Removal of next free support bars line

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IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details of dismantling the CRD-H line by line
Reminder: 7-Removal of next free support bars line

C1 - Interne

8-Removal of CRD-H line + Next support bar line

9-Removal of CRD-H line + Next support bars line

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

CRD-H dismantling line by line
Reminder: 9-Remove CRD-H line + Next support bars line

C1 - Interne

10-Removal of CRD-H line + Next support bars line

11-Removal of CRD-H line + Next support bars line

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

Details Dismantling CRD-H line by line

Dismantling of a CRD-H line
Front HCU cutout of the first row of the line
Rear HCU cutout of the first row of the line
CRD-H cutout first row of the line

GRID cutout of the first row of the line
ICM cutting of the entire next row in the line
Next row in the line
Next line

Rows are cut asfollowed as the rankby-rank methodology
excluding support bar
that are cutted later

Dismantlingof the free support bars line
Dismantling of the free hanging rods line
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

SYNTHESIS OF CONFIGURATIONSUSED FOR 1 ARM SCENARIO

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.10

DISMANTLING SCENARIO – APPROACH 2.1

SYNTHESIS OF CONFIGURATIONSUSED FOR 2 ARMS SCENARIO

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.11

DAMAGED EQUIPMENTS MANAGEMENT
Damaged HCU scenario

Possible Damaged
Situation

Scenario
impactAlternative scenario

Feasibility Test

Limit

Additionnal information

Contaminated water
insideYES

YES Additionnal phase to empty:
drilling HCU

YES, draining shoot donein CEA/No too high pressure during
drilling => contaminatedwater remains in thepedestal

One HCU on the CRD-H
is missingNO

Not needed

/

/

/

Twisted

YES

Specific Clips or shears

/

/

/

Welded to the CRD-H

YES

Additionnal phase: laser cutting
to free space for the clip

YES, same as long
distance cut of HCU//

Damaged elements will take longer to process than an intact element. This variation is estimated to be 20-50% more time depending on the size and initial complexity of the element.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.11

DAMAGED EQUIPMENTS MANAGEMENT
Damaged CRD-H scenario

Possible Damaged
Situation

Scenario
impactAlternative scenario

Feasibility Test

Limit

Additionnal information

Full of Fuel DebrisNO

Not needed

YES, thickest CRD-H
configuration//

Partial lack of external
layer

YES

Additionnal phase: using
cylindrical bucket

/

/

/

Top part of CRD-H
broken blocked in the
structure

YES

Depending of blocking/

YES, if access toblocked part is too
limitedRequire additionnal
investigation

Flange overloadedwith corium

YES

Additionnal phase: laser cut insmaller parts the flange/

YES, needs the 2arms configuration/

Twisted CRD-H

NO

YES, same as angular cut/

Maybe smaller parts

Missing grid below theflange

YES

/

/

/

Additionnal phase: set therecovery bucket or the recovery
platform

Damaged elements will take longer to process than an intact element. This variation is estimated to be 20-50% more time depending on the size and initial complexity of the element.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.11

DAMAGED EQUIPMENTS MANAGEMENT
Damaged ICM scenario or damaged rod scenario

Possible Damaged
Situation

Scenario
impactAlternative scenario

Feasibility Test

limit

Additionnal information

Broken Bottom part

NO

/

/

/

/

Unable to reach

YES/

YES, long distance cut

More than 500 mm/

Top part broken andblocked in the structure

YES

Depending of blocking//

Require additionnal
investigation

Twisted ICM/rod

NO

/

/

/

/

Damaged elements will take longer to process than an intact element. This variation is estimated to be 20-50% more time depending on the size and initial complexity of the element.
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.11

DAMAGED EQUIPMENTS MANAGEMENT
Damaged grid scenario or damaged support bar scenario

Possible Damaged
Situation

Scenario
impactAlternative scenario

Feasibility Test

Limit

Additionnal information

Impossibility to set therecovery bucket

YES

Set the recovery platform

/

/

/

WeldedYES

Additionnal cut

/

/

/

Unable to reach

YES/

YES, long distance cut

More than 500 mm/

One rod is missing

NO

/

/

/

/

Possible Damaged
Situation

Scenario
impactAlternative scenario

Feasibility Test

Limit

Additionnal information

Central part of thebeam broken

NO

Compatible with one of the
proposed scenario/

YES if more than 3
beams damaged
side by side/

Central beam twisted

NO

Compatible with one of the
proposed scenario

/

/

/

Damaged beam scenario

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENT

Assumptions and estimates of elements to be dismantled
For the studies, a number of intact and damaged elements in the pedestal were estimated. Between 20 and 40% of the elements are damaged, mainly those in the center of the pedestal. The
following figures are estimated for the pedestal of a single reactor unit (reactor unit 2 or 3).

Estimated number of elementsin the pedestal

Estimated number of damaged
elements in the pedestal

30

CRD-H

/ 137

30

HCU pairs

/ 137

15

ICM

/ 50

Grid elements

25

Grid elements/ 75

Deformed, merged withother elements, skewed, etc.

88

Support bars

25

Support bars

/ 88

Longer to dismantle

95

Hanger rods

30

Hanger rods

/ 95

8

Beams

2

Beams

/8

137

CRD-H

137

HCU pairs

50

ICM

75

For an intact pedestal

The events caused damage to thepedestal and therefore to theelements to be treated

Between 20 and 40% of theelements were damaged

For a damaged pedestal

Damaged elements will take longer to process than an intact element. This variation is estimated to be 20-50% more time depending on the size and initial complexity of the element.
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IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENTDismantling time with 1 arm configuration
The scenario with a 1-arm configuration is the longest of the scenarios presented. The main constraints with this configuration are the multiple tool and configuration changes (alternation between
cutting tool and gripping tool) and the need to constantly install local fall arrest solutions to retain the dismantling element.

For one reactor unit

C1 - Interne

662

Dismantling with a 1 arm configuration scenario

CRD-H

137

HCU pairs

50

ICM

75

Grid elements

88

Support bars

95

Hanger rods

8

Beams

137

with a 1 arm configuration

5003

Hours

137

with a 1 arm configuration

4756

Hours

50

with a 1 arm configuration

1370

Hours

75

with a 1 arm configuration

273

Hours

88

with a 1 arm configuration

95

with a 1 arm configuration

8

with a 1 arm configuration

DISMANTLING TIME

137

CONFIGURATION FOR DISMANTLINGELEMENTS TO BE DISMANTLEDFOR ONE REACTOR UNIT (2 OR 3)

x1

155

Hours

1993

Hours

351

Hours

Days

=

579
days

1,81

+
+

For all reactor units

Years

1724

Equipment maintenanceand availability
Waste disposal“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

Days

=

662
days

=

4,72

Years

1724
days
FOR ALL 3
REACTOR
UNITS

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENTDismantling time with 1 arm configuration
The breakdown of days to dismantle the 3 reactor units with this configuration is shown below. The number of days associated with the performance of the cutting tool (laser tool) is fixed and isestimated at 80 days (which represents about 5% of the total estimated time). The longest times are for tool and configuration changes and gripping tool management.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENT

Hypothesis of the dimensions of the cut sections leading to cutting length
The size of the cut sections of an element is calculated so as to respect the dimensional constraints of the waste containers (UC and MUC) as well as to respect the lifting capacities of the system.
For small components, their cut-outs are sized so that as many as possible can be placed in the associated container (while respecting the maximum mass imposed). Otherwise, for larger
components (such as a CRD-H), they are sized to fit as snugly as possible into the container.
- For the CRD-H (not including the flange), these are cut into 9 pieces so thateach section can be fitted with an MUC container (each section is 340mm long).
- For the HCUs, these are cut into 15 pieces so that each section can be fittedwith a UC container (each section is 330mm long on average).
- For the ICMs, these are cut into 12 pieces so that each section can be fitted
into an MUC container (each section is 340mm long).
- The pieces of the grid structure are cut into 8 pieces so that an entire element
can be integrated into an MUC container.
- The support bars are cut into 2 pieces so that 2 complete elements can be
integrated into an MUC container.
- The tie rods are cut into 11 pieces, so that a whole element can be fitted into a
UC container (each section is 345mm long).
- For the beams, they are cut so that each small piece can be integrated into a
UC container.
The number of cutting parts multiplied by the section of each part leads toa cutting length close to 1,5 km.
Example of UCMUC filling

Example of cutting a CRD-H
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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENTDismantling time with a combined configuration of 1 arm and 2 arms
Compared to the 1-arm configuration, the 2-arm configuration is much faster since the processing time of the elements is shortened (possibility to perform cutting and gripping operations inparallel). This scenario is not purely with 2 arms since the space requirement in the pedestal requires processing of the elements with 1 arm first (in order to allow deployment of 2 arms).

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENTDismantling time with a combined configuration of 1 arm and 2 arms
The breakdown of days to dismantle the 3 reactor units with this configuration is shown below. The number of days associated with the performance of the cutting tool (laser tool) is fixed and isestimated at 80 days (which represents about 7% of the total estimated time). Compared to the pure 1-arm configuration, this one requires more maintenance as 2 arms are deployed.
Approximately 30% days saved compared to a purely 1-arm configuration.

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IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENTDismantling time in different configurations
At first, estimates of dismantling times were made according to 2 selected scenarios: with a 1 arm configuration & with a combined 1 arm and 2 arm configuration. These time estimates take into
account all dismantling operations (processing of all elements to be dismantled, movement of the system, operator reflection, maintenance, etc.).

For one reactor unitx1

x2

For all reactor unit

Dismantling with a 1 arm configuration scenario

662

Days

=

1,81

Years

1724

Days

=

4,72

Years

Dismantling with a combined 1-arm and 2-arm
configuration

458

Days

=

1,25

Years

1172

Days

=

3,21

Years

Estimate for reactor unit 2 or 3

Estimate for reactor unit 1, 2 and 3

Onet Technologies CN considers that Reactor Unit 1 is smaller than Reactor Units 2 and 3. There are fewer components to dismantle inside Reactor Unit 1: it is faster to dismantle.

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IV. IMPLEMENTATION STUDIES
4.12

OPERATIONAL TIME – ESTIMATION OF DISMANTLING TIME & WASTE MANAGEMENT

Balance of waste treated, number of cuts and containers deployed
In order to support the time calculations needed to estimate the dismantling time, calculations were made to determine the total number of cuts to be made, the total cutting distance, the total
mass of elements to be dismantled and the number of waste disposal containers to be deployed (for the 3 units). Briefly, the results of the calculations for each of these categories are given below .

DISMANTLING

Final state (the 3 reactor units)

Initial state (the 3 reactor units)•
Unit Can•
Mitigating Unit Can

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Approximately 220,000 kg of waste to be extracted

This is a primary waste balance: induced waste (produced by the cutting tool or fall
prevention solutions for example) is not considered. Only dismantled elements are
considered.

Approximately 3,750 waste containers to be deployed(Around 1800 Unit Can and 1950 Mitigating Unit Can)With maximum filling of each container with pieces of the same category (dismantlingorder) cut to dimensions defined by the established scenario.

•

Approximately 21,700 cuts

For an average of around 64 mm per cut.

•

Approximately 60 kg of waste on average percontainer

And approximately 70 kg including the weight of the container (UnitCan or Mitigating Unit Can).

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V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.1

RISKS & OPPORTUNITIESRemaining risks

Theme

TopicsRisk:
Performanceworksite

Laser design

Risk: Fall
prevention

Risk : Initial
State

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Robotics arms

Dismantlingscenario

Risk and challenge
Unsuccessful cutting of CRD-H due tolimited power of the bent laser head
(8kW)

Fall of a broken part on the robotic arms

A broken part in balance in the structure
Too many possibilities of situations

Potential impact

Action plan proposal

Impossibility to unroll the scenario due to alack of power

Design and develop a higher power bent laser head
up to 14kW

Robotics arms blocked in the pedestal

Scenario already limit exposure to this risk
Investigate in detail the part at the entrance of thepedestal
Design and develop a robotic arm structure to lower
the risk of jamming

Difficulty to unroll the scenario

Improve knowledge of the pedestal through visual
investigation
Define a platform that can resist to the fall of a CRD-H
from 3 meters (martyr tiles protective mat for
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V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.1

RISKS & OPPORTUNITIESRemaining risks

Theme
Opportunity :Performanceworksite

Risk&Opportunity :Fall prevention

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TopicsRisk and challenge

Robotics arms

Set as soon as possible the two arms
robotics solution
And automate part of interventions

Fuel debris

Fall of a damaged part on the fueldebris.
Set quickly in place a bench of “sand”
or neutrophage balls on the fuel debris
and then martyr tiles protective mat

Potential impact
Important gain on time schedule

Action plan proposal
Study and develop both robotics arms solutions :the one with one arm and the one with two arms
Develop an automatic trajectory system
Study to define the safety requirements, thecompatible materials, the calculation sizing andthe scenario to implement the solution

Possible criticality accident
Opportunity: allow the fall of object during theworksite on those martyr tiles, greatly simplify
one arm scenario and replace the platform“Project of Decommissioning, contaminated water and Treated Water Management(Development of Control Rod Drive Housing cutting and removal technologies)”

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V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.1

RISKS & OPPORTUNITIESFall prevention : highest risk and probably highest opportunity
Recent investigation results in F1 show a high level of damages of the concrete walls.
Nota: These damages are not compatible with most of the platform concept.
The weakness of this state induces, in case of an earthquake, a raise of the risk a part to fallon the Fuel Debris without any control.
A proposal to lower this risk can be to set in place a shock absorbing layer.

This shock absorbing layer has to meet two challenges:- Be easily spread on the Fuel Debris- Maintain integrity during the fall of an object
Onet proposes a two layers concept platform :- A first layer to cover the fuel debris safely- A second layer made of martyr tiles to resist fallen object shock

Martyr tiles layer

Specific material balls tocover fuel debris

Filling the bottom of the pedestal

Shock absorbing platform concept
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V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.1

RISKS & OPPORTUNITIESFall prevention : highest risk and probably highest opportunity
Explanation about the highest opportunity :Once such a platform is set, the need and/or the requirement to prevent the fallof any cut parts does not exist anymore.
Nota: the cutting preparation includes to set in place the prevention fall system,
which is an important part of the planning.
Without the prevent fall requirement :- Dismantling scenario becomes easier- Mechanical systems (robotic arm, …) are simplified- The waste management can be optimised, by chosing the cut parts

This is why it is probably the highest opportunity, that has been
evaluated through a time schedule estimation.

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.1

RISKS & OPPORTUNITIESFall prevention : highest risk and probably highest opportunity-945days

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DEVELOPMENT OF CONTROL ROD DRIVE HOUSING CUTTING AND REMOVAL TECHNOLOGIESPUBLIC REPORT

V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.1

RISKS & OPPORTUNITIESFall prevention : highest risk and probably highest opportunity
Estimates of dismantling times were made according to 3 selected scenarios: with a 1 arm configuration; with a combined 1 arm and 2 arm configuration and a combined 1 arm and global shock
absorption solution. These time estimates take into account all dismantling operations (processing of all elements to be dismantled, movement of the system, operator reflection, maintenance,etc.) but this does not consider the installation of the potential global fall arrest solution.

For one reactor unitx1

Dismantling with a 1 arm configuration scenario

662

Days

=

1,81

For all reactor unit

Years

1724

Days

=

4,72

Years
-60%

x2
x1

Dismantling with a combined 1-arm and 2-arm
configuration

458

Days

=

1,25

Years

1172

Days

=

3,21

Years

Dismantling with a scenario of a 1 arm configuration andthe global fall arrest solution “Shock-absorbing layer”

282

Days

=

0,77

Years

717

Days

=

1,96

Years

Estimate for reactor unit 2 or 3

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Estimate for reactor unit 1, 2 and 3

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V. RISKS & OPPORTUNITIES AND GLOBAL SYNTHESIS OF THE PROJECT
5.2

Global synthesis of the project

The tests and study of this project have permit to :- compare and give an orientation in the choice of cutting tool for CRD-H- propose a bunch o technical solutions to prevent the fall of object- confirm the reachability and feasibility of tele-operability- establish a scenario to dismantle the CRD-H zone with a one robotic arm solution equiped with a cutting laser head- propose variants to take into account the 1F actual situation, a damaged installation- give a first estimation of the duration of worksite

To be fully feasible, this scenario requires the development of a 14kW bent laser head.
The shock absorbing layer, if feasible, represent a great opportunity to lower the earthquake risk
and, at the same time, simplify and accelerate worksite dismantling.
Another great potential acceleration of onsite work is to develop an automate trajectory generator.

Thank you for your attention.

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