Remote Maintenance

Sub-topicDEMO Service Joining Technology

Joint Special Design Team for Fusion DEMOQST Rokkasyo Fusion Institute

Naka Fusion Institute

IAEA WORKSHOP, DAEJEON, KOREA2018, 7th-10th May

Satoshi Kakudate

Do we have the Service Joining Technologyrequired for DEMO?

□ Service joining Technology- Cooling pipe handling technology- Welding and Cutting , Non-detective test technology

□ To answer question titled in this page , the following service joining designand technology are presented based on EU DEMO and JA DEMO design

Design related to cooling pipe- Requirement of Cooling Pipe- Cooling pipe layout in upper port- Cooling pipe handling

Current R&D status- Laser and TIG welding- Cutting- Non-detective test- Radiation hard component

Future action to fill the gap between current technology and Technologyrequired for DEMO

Design Requirements of Cooling Pipefor Vertical Maintenance

EU DEMO

PipeNumber of pipes

per upper port

Pipe inner

dameter

(mm)

Pipe wall

thickness

(mm)

Coolant per Blanket 4 200 15

LiPb Breeder per Blanket 2 75 5

Coolant per neutron shield 2 80 5

Referencek.keogh*1, et.al., Fusion Engineering and design(in press)https://doi.org/10.1016/j.fusengdes.2018.02.098*1 RACE, UK Atomic Energy Authority

Vertical portblanket extraction handling

Design Requirements of Cooling Pipefor Vertical Maintenance

Port with pipe locations

Exploded proof of principle tool design

- In-pipe welding- Fitting the weld groove using

pipe alignment feature

Pipe alignment feature

EU DEMO

Referencek.keogh*1, et.al., Fusion Engineering and design(in press)https://doi.org/10.1016/j.fusengdes.2018.02.098*1 RACE, UK Atomic Energy Authority

Design Requirements of Cooling Pipefor Vertical Maintenance

JA DEMO

Load specifications

Pressure

(MPa)

Coolant Inlet

Temperature

(Degree)

Coolant Outlet

Temperature

(Degree)

Blanket module 15.5 290 325

Back Plate 3 200 210

Parge gas for Tr

collection0.1 27 325

Purge gas forTr collection

Size of Cooling pipes

MaterialOuter diameter

(mm)

Thickness

(mm)

Number of

pipe per

one port

Blanket module SUS316 216.3 23 2 for in-board segment

267.4 28.6 2 for in-board segment

216.3 23 6 for out-board segment

Back Plate SUS316 42.7 3 10

Parge gas for

Tr collectionSUS316 27.2 2.1 10

Purge gas forTr collection

Design Requirement for Cooling pipe

(1) Total number of pipes : 30 pipes/port * 16 ports = 480 pipes(2) Replacement Frequency : every 3 years ( tentative)

Scheduled replacement of blanket modules every 3 years(3) Cooling pipes layout (configuration) in upper port without

interference between cooling pipes and blanket segment in caseblanket segments removal

(4) Unit structure（Unitization ）of cooling pipes related to one blanketsegment for easy handling

(5) Radiation dust Handling during cooling pipe maintenance

Design example in past( Design modification need to meet (3) and (4) requirements.)

JA DEMO

Cooling Pipe Layout in Upper Port(Revised version)

Cryostat Primary closure platePort bellows

Port openingPlane view

Coverfor cooling pipes

Center segment

Inboard segment

- Cooling pipe location under primary closure plate- Ensuring the access space for pipe welding, cutting & inspection Tool- Installation in both sides of port for independent removal of each blanket segment- Cover pipes with bellows in cryostat

Cooling Pipes

Cooling Pipes

JA DEMO

Unit structure design for pipes

Unit structure for cooling pipesof outboard center

Unit structure forinboard

Unit structurefor outboard side

- Five unit structure for pipe support- Support for pipes based on requirement of

thermal expansion- Positioning of unit structure along guide- Flexibility to fit between welding grooves- Independent installation & removal of unit

structure- Access from outside of pipe for

welding/cutting/inspection

GuideJA DEMO

Removal of center Segment(For example)

Step-1: Removal of primary closure plateStep-2: Pipe cutting ( two locations of vertical and horizontal )Step-3: Removal of unit structure for cooling pipes of outboard center

Other unit structures remain in port without cuttingStep-4: Removal of outboard center blanket segment

unit structure forcooling pipes ofoutboard center

Unit structurefor outboard side

Unit structure forinboard

Outboardblanket segment

JA DEMO

Cooling Pipe Handling

Bio-shield &radiation dust containment

Transfer caskfor cooling pipe & blanket segment

Guide rail fortransfer cask

Hot Cellfor receiving& supplying

Rotation bridgefor port access

Major specificationTransfer cask- Without bio-shield- Transfer of in-vessel components from

tokamak to hot cell- Avoidance of spreading radiation dust- Use for cooling pipe & blanket segment

handling commonly- double seal door ( cask door and port

door)

Rotation bridge- Support of transfer cask- Max. acted loads : about 200 ton

included blanket segment

JA DEMO

Cooling Pipe Handling

- Transfer cask, telescopic manipulator and lowing & elevation are used commonly incase blanket maintenance

- Attachment with dexterous manipulator is changeable to end-effector for blanketsegments

Unit structure

Lowering &elevatingmechanismwith X-Ytable

Telescopicmanipulator

Transfer cask

Rotation bridge

Dexterousmanipulator

Attachment

Guide

Blanketcooling pipe D ivertercooling pipeO utterdiam eter(m m ) 42.7 71W allthicness (m m ) 2.73 about3Num berofm oduls orcassets about440 54Num berofLocations ofw elding 4 perone m odule

Blankerm aintenace D iverterm aintenace

M aintenace C lassificationFirastW all:class 1Shield block :class 2

class 1

Access inner outter

W eld typeO ne pass laser

orO ne pass TIG

C utting tipeSw age cutterforpipe

M illing forplug

W eld property com patible Vaccum Handbook

ND TUTor

Pre-proofsam pling

Radiation (G y/hr) 250 300

ITER

Maintenance technology for blanket cooling pipe( JA activity)

- Laser and TIG welding- Cutting- Non-detective test- Mechanical connector

ITER requirement of Blanket and diverter

References- ITER Technical BASIS- H.Tanigawa et al., FED vol. 98-99, 2015- S.Shigematsu et al., FED vol. 87,2012- M.Saito et al., FED vol.124,2017- K.Obara et al., JAERI-Tech 99-003- ITER Remote Handling Code of Practice

Requirement Welding and Cutting for ITER

Requirements for welding/cutting:

For in-pipe- Inner access from pipe- Pipe inner diameter: 42 mm- Weld thickness : about 3 mm- Welding location :

250 mm from first wall surfaceFor plug- Diameter: 49 mm- Thickness : about 3 mm- Welding location :

160 mm from first wall surface

First wall

Shieldblock

Cooling pipe configuration

Vacuum vessel

Developed technology to replace FW:

- Welding , Cutting and inspectionfor pipe and plug

250

Plug

pipe

Pipe Welding / Inspection, Cutting Technology

(1) Welding ( inner access )(a) Comparison between Laser and TIG regarding One pass

welding to apply the in-pipe access(b) Welding of plug using Laser(c) Inspection

(2) Cutting(a) Swage cutter for pipe ( in-pipe access)(b) Milling for plug

(3) Radiation hardness components for welding, cutting andinspection tools

The following technical issues were summarized based oncurrent technology;

Requirements for The Welding

1 . Welding time

2. Lower heat input, one pass welding without filler material

3. Smaller amount of welding fumes and spatter

4. Weld property compatible with ISO 1319 andinternal standards (ITER Vacuum Handbook)

5. Allowable misalignment compatible with assembly tolerance

6. Long duration of life

Specifications of test tool for weld- Tool outer Diameter: 38.8 mm- Inner diameter of pipe: 42.72 mm- Collection of weld fume : N2 gas- Cooling of mirror and lens: N2 gas- Optical fiber- Mirror and lenses- Dichroic mirror

Laser welding for Validation Test

Weld parameters- Output power: 2.8 kW- Laser spot diameter: Φ1.2 mm- Welding speed: 1.0 m/ min- Heart input: 1.7 kJ/cm- Flow rate for Collection fume

and cooling gas: 80 L/min- Measurement of Weld Route gap using camera

TIG Welding for Validation Test

Specifications of test tool for weld- Tool outer Diameter: 34.1 mm- Inner diameter of pipe: 42.72 mm- Inner gas : Ar + He gas- AVC( Control for distance between

W electrode and pipe surface- Rotation mechanism- Outer gas : N2 gas

Weld parameters

Pressurization for preventing thedrop of welded metal

Confirmation of Weldability due toExpanding the allowable gap

Fitting errors have two types, such as gap and linear misalignment.

Allowable miss alignment of weld groove:Gap= 0.2mm, LM=0.7 mm

Test Results for Laser welding

Linear misalignment of 0.7 mmGap of 0.2 mm

Test Results for TIG

Allowable miss alignment of weld groove:Gap= 0.5mm, LM= 1 mm

LM = 1 mm LM = 0.6 mm

Comparison of Life Timebetween Laser and TIG Welding

10th 30th 50th

Attached spatter : slight

Durability of mirror was increased, so that weld more than 50times was possible continuously .

Laser

TIG

Comparison of Weld Performancebetween Laser and TIG

Laser with small heat input will selected if high priority is to preventHe bubbles and to use over long duration.

Trial to Expand Allowable Gap using Laser

23

Normal fitting configuration for laserGap

Proposal of special fitting configuration to expand allowable gap

To ensure weldability, gap alignment less than 0.2 mm need.To achieve this gap alignment by remote handling is difficult.

2.77

2.77

0.5

laser beam

2.5

Gap

Target allowable gap : more than 0.5 mm

24

Test Results

0º (top) 180º (bottom)

Gap = 0.7 mm

Weld parameters- Output power: 3.5 kW- Laser spot diameter: Φ1.2 mm- Welding speed: 1.0 m/ min- Heart input: 1.9 kJ/cm- Laser beam location ( Distance L ) :

1.5 mm- Flow rate for Collection hume

and cooling gas: 80 L/min

Weld fume attached with pipe and tool

-

2.77

laser beamGap

L

The 0.7 mm of allowable gap in case of special fitting groove is confirmed underupper weld parameters. On the other hand, weld fume produced by weld is much.

Selection of Non-destructive Inspectionin Current Technology

Before welding After welding

Weld bead

Applicability of non-destructive inspection in vessel

In current technology, applicability of UT is difficult because of detecting somefalse defects. Visual test using computer vision will be available. Trial results forvisual of in-pipe through dichroic mirror attached laser welding tool is shownbelow.

Defect type Non-destructive inspection Applicability for in-vessel Remarks

Surface Visual test (VT) Available

Penetrant Test (PT) NG Removal of paint need.

Volume Ultrasonic Test (UT) Difficult Clarification of false defects

Digital Radiographic Testing (D-RT) NG Radiation environment

Reallyfittedgrooves

Center of laser spot

Ideally fitted grooves(Black lines)

Plug welding

First wall

Shieldblock

Cooling pipe configuration

250

φ60

φ69φ59

φ48.72

Be & Cu

StainlessSteel

Plug

16

0

Requirements

Access hole Diameter: 60 mmDistance : 160 mmDiameter of plug : about 49 mmThickness of plug : 3 mm

Trial test to clarify the welding parameter

- Laser power- Diameter of laser beam- Distance between welding location and fitting (L)

L PlugLaser beam

Fitting forwelding

Test Results

Output

laser

power

kW

Weld

speed

m/min

Gap

Position of

laser beam

mm

Penetration

of beam

Visual

testPT RT

D 1 0.8 NG NGD 2 2.5 0.8 0 0.9 G ood NGD 5 1.1 G ood G ood G ood G ood

VT: NGnot

Penetration

D1 D2 D5

VT, PT,: good

Welding parameters of D5 is good.

Mechanical Cutting Technologyfor pipe cutting

Requirements

- In-pipe cutting- Inner pipe diameter: 42 mm- Pipe thickness : 3 mm- Swarf-less ( Swarf are not produce during

cutting)- Dry cutting ( without using lubricant)- Cutting method : swage cutter type

Design of tool head- Tool diameter : 40.5 mm- Cutting motion : 4.5 mm- Rotation : without limitation- Diameter of cutter : 18 mm

Rotation

Detail

Cutting motion

29

Cutting for Validation Test

Cutting parameters- Cutter material (Commercial base) :

SKH51 ( Hardness 781 to 809 HV)- Cutting motion speed : 0.02 mm/s- Rotation speed : 30 rpm

Test results- Cutting time : about 3 min.- Without swarf- Acted motor torque :

less than rated torque- Deformation of inner and outer dia. :

less than 0.1 mm- Surface roughness : Ra < 0.7 mm- life time

In case of dry cutting( without lubricant) : 8 to 10 timesIncase of using lubricant (MOS2) :

more than 46 times

After cutting(without lubricant)

Damage(without lubricant)

Cutting tool

Cutting tool design for swarf-less is validated.

Requirements

- Plug diameter : about 49 mm- Thickness : 5 mm- Dry cutting ( without lubricant)- Cutting method : milling type- collection of swarf

Mechanical Cutting Technologyfor Plug

49

Pipe

Plug( Blue )

Design of cutter

Cutter

Plug

Flow direction (vacuum)for swalf collection

vacuum forswalf collection( No rotation)

Interface of rotation

Cutter(Rotation)

31

Collected swarflife time more than 200 holes

Cutting for Validation Test

Cutting parameters- Cutter material : TC- Number of cutting tips : 6- Dry cutting (without lubricant)- Cutting motion speed : 0.04 mm/s- Rotation speed 24.2 m/min- Vacuuming flow rate : 1.7 m3/min

Test results- Cutting time : about 2.5 min.- Collection of swarf- Acted motor torque :

less than rated torque- life time : more than 200 times

Cutting tool design for swarf-less isvalidated.

Mechanical connector

ReferenceRajendran S. , Palmer J. , Tesini A. ,ITER Remote Handling Code Practice

400 bar = 40MPa

- a raised button for disconnection using a manipulator- O-ring seal: Nitrile- Flourocarbon (Viton) seals can be specified if

required.

Summary of Service Joining Technologyfor Demo Remote Handling

Gaps of RequirementsITER Vertical Maintenance for DEMO

Blanket Divertor JA EUPressure (MPa) 4 4.2 15.5 (Max.) ? (Max.)Temperature (Deg.) 148 150 325 (Max) ? (Max.)Outer diameter (mm) 42.7 71 267.4 (Max.) 230 (Max.)Wall thickness (mm) 2.73 about 3 28.6 (Max.) 15 (Max.)

Access Inner Outer Outer Inner

Weld type

One pass laser(Primary)

One pass TIG(Option)

TBDTBD

Cutting typeSwage cutter

for pipeMilling for plug

TBD TBD TBD

NDT

UT

orPre-proofsampling

TBD TBD

Weld propertycompatible

VacuumHandbook

TBD TBD

Radiation (Gy/hr) 250 300 100 ?300

Future Actions to Fill Gaps between CurrentTechnology and Technology required for DEMO

Major gaps- Welding and non-destructive test against thick-

walled pipe of 30 mm for JA and 15 mm for EU

Action to fill the gapsPhysical testing to ensure the weldability of pipe weld

for DEMO by remote handling, such as weld and non-destructive test

□Welding method of thick-walled pipeTIG using filler metal, One pass laser, Laser using filler metal

□Selection (tentative): Laser using filler metal (primary recommendation),One pass laser (2nd)TIG using filler metal (3rd)

Considering the following selection parameters,

- Welding time- Rough fitting accuracy of groove for weld,- Life duration- Size of weld tool- Radiation hardness

Future Actions to Fill Gaps(Welding)

□R&D items for the selected weld methodPhase-1:Comfirmation of weldability using commercial base- Control of weld cracks (control of ferrite by filler metal to avoid weld crack)- Drop of weld metal to avoid sag- Weld parameter without weld inspection on backside- Rough fitting accuracy range of groove for weld- Power, speed, spot diameter,- suppression of fume- Back shied gas(with or without)

Phase-2:Design and Validation test based on results of Phase-1- Design for weld tool head with degree of freedom for positioning- Validation test( included in phase-1 parameters )- Selection of weld property compatibility with standard

if necessary, internal standard will be studied.

Phase-3:Demonstration by prototype- Design of prototype based on results of Phase-2- Confirmation of meeting weld property compatibility with standard

decided in phase-2 by demonstration

Continue

Defects for surface: Visual test

R&D of computer vison technology need to detectthe following defects on weld bead.- Root concavity- Undercut- Excess weld metal- Small Crack

Future Actions to Fill Gaps(Non-destructive test)

Defect for volume : UT ?In current technology, applicability of UT is difficult because of detectingsome false defects.R&D of method without detecting false defects, such as EMAT etc.,need , such as- Process processing- Without cuplant ?- Alternative method of UT ( compact linac) ?

(Application of advanced technology)Check of molten weld poolby highly sensitive camera during weld- passing through dichroic lens and fiber- confirmation of locations between

weld pool and laser spotby visualization of welding

- selection of weld speed, power and so onfor high weld quality

Future Actions to Fill Gaps(Non-destructive test)

( For example)

fume

sputter

laser spotweld pool

Summary

The following design and technology were summarized;

(1) Pipe Layout for Remote handling compatible for FusionDEMO

(2) Current technology of welding and cutting for remotehandling

(3) Future Actions to fill gaps between ITER and Fusin DEMOregarding welding and Non-destructive test for fusionDEMO

Reference1) k.keogh*1, et.al., Fusion Engineering and design

(in press)*1 RACE, UK Atomic Energy Authority

2) Rajendran S. , Palmer J. , Tesini A. ,ITER Remote Handling Code Practice

3) ITER Technical BASIS

4) H.Tanigawa et al., FED vol. 98-99, 20155) S.Shigematsu et al., FED vol. 87,20126) M.Saito et al., FED vol.124,20177) K.Obara et al., JAERI-Tech 99-0038) ITER Remote Handling Code of Practice