Development of the high heat flux component for a fusion reactor

M Tokitani a Y Hamaji a Y Hiraoka b S Masuzaki a H Tamura a H Noto a T Tanaka a T Muroga a A Sagara a

and FFHR Design Group a

a National Institute for Fusion Scienceb Okayama University of Science

4th meeting of the Radiation Damage In Accelerator Target Environments (4th RaDIATE)

125

Contents

225

Heat flux distribution to the Helical reactor wall

Required heat removal capability of the ldquoDivertorrdquo

Alpha () heating power ~600 MW

Divertor (strike point) 32 m2

Possible power balance

ldquoDivertorrdquo needs the highest heat removal capability among the fusion reactor wall

~500 MW

Over ~10 MWm2

Fusion power gain 1 GWPower conversion efficiency 33Required power output sim3 GW

D + T 4He (352 MeV) + n (1406 MeV) Candidate fusion reaction

Helical Reactor FFHR‐d1

First wall 12800m2

~100 MW

325

Rc=156m

Contents

425

Material selection for ldquoDivertorrdquo heat sink Required heat removal capability in the reactor divertor

0 5 10 15 200

200400600800

100012001400

Cu alloy

RAFM

t=1mm

Ther

mal

str

ess

[MPa

]

Input power [MWm2]

t=1mm

Induced internal thermal stress by a temperature gradient between surface and back surface as a function of an input power in the 1 mm thickness of RAFM and Cu alloy

σ=Eε=EαΔT

Heat loading limit of RAFM steel and Cu alloy

RAFM cannot withstand under high heat load (Over ~75 MWm2) Cu alloy is almost sole solution of the divertor heat sink in the reactor

‐ TC30 WmK (RT)‐ E 200 GPa‐ 10 K

‐ TC 350 WmK (RT)‐ E 120 GPa‐ 165 K

E Youngs modulus [Pa] Thermal exp coeff [K‐1]

525

Over ~10 MWm2

Yield strengthYield strength

RAFM

High resistant to a neutron irradiationLow thermal conductivity

Cu alloy

Low resistant to a neutron irradiationHigh thermal conductivity

Cu alloys are low resistant to a neutron irradiation Can be available under the neutron loading

(a) Vertical cross‐section (b) Horizontal cross‐section Distribution of the fast neutron flux in FFHR‐d1 (gt01 MeV)

T Tanaka et al Fusion Eng Des 89 (2014) 1939

Acceptable value for a reactor running 625

We designed the divertor space located on the deep position surrounded by other wall components

~ 01dpayear

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Contents

225

Heat flux distribution to the Helical reactor wall

Required heat removal capability of the ldquoDivertorrdquo

Alpha () heating power ~600 MW

Divertor (strike point) 32 m2

Possible power balance

ldquoDivertorrdquo needs the highest heat removal capability among the fusion reactor wall

~500 MW

Over ~10 MWm2

Fusion power gain 1 GWPower conversion efficiency 33Required power output sim3 GW

D + T 4He (352 MeV) + n (1406 MeV) Candidate fusion reaction

Helical Reactor FFHR‐d1

First wall 12800m2

~100 MW

325

Rc=156m

Contents

425

Material selection for ldquoDivertorrdquo heat sink Required heat removal capability in the reactor divertor

0 5 10 15 200

200400600800

100012001400

Cu alloy

RAFM

t=1mm

Ther

mal

str

ess

[MPa

]

Input power [MWm2]

t=1mm

Induced internal thermal stress by a temperature gradient between surface and back surface as a function of an input power in the 1 mm thickness of RAFM and Cu alloy

σ=Eε=EαΔT

Heat loading limit of RAFM steel and Cu alloy

RAFM cannot withstand under high heat load (Over ~75 MWm2) Cu alloy is almost sole solution of the divertor heat sink in the reactor

‐ TC30 WmK (RT)‐ E 200 GPa‐ 10 K

‐ TC 350 WmK (RT)‐ E 120 GPa‐ 165 K

E Youngs modulus [Pa] Thermal exp coeff [K‐1]

525

Over ~10 MWm2

Yield strengthYield strength

RAFM

High resistant to a neutron irradiationLow thermal conductivity

Cu alloy

Low resistant to a neutron irradiationHigh thermal conductivity

Cu alloys are low resistant to a neutron irradiation Can be available under the neutron loading

(a) Vertical cross‐section (b) Horizontal cross‐section Distribution of the fast neutron flux in FFHR‐d1 (gt01 MeV)

T Tanaka et al Fusion Eng Des 89 (2014) 1939

Acceptable value for a reactor running 625

We designed the divertor space located on the deep position surrounded by other wall components

~ 01dpayear

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Heat flux distribution to the Helical reactor wall

Required heat removal capability of the ldquoDivertorrdquo

Alpha () heating power ~600 MW

Divertor (strike point) 32 m2

Possible power balance

ldquoDivertorrdquo needs the highest heat removal capability among the fusion reactor wall

~500 MW

Over ~10 MWm2

Fusion power gain 1 GWPower conversion efficiency 33Required power output sim3 GW

D + T 4He (352 MeV) + n (1406 MeV) Candidate fusion reaction

Helical Reactor FFHR‐d1

First wall 12800m2

~100 MW

325

Rc=156m

Contents

425

Material selection for ldquoDivertorrdquo heat sink Required heat removal capability in the reactor divertor

0 5 10 15 200

200400600800

100012001400

Cu alloy

RAFM

t=1mm

Ther

mal

str

ess

[MPa

]

Input power [MWm2]

t=1mm

Induced internal thermal stress by a temperature gradient between surface and back surface as a function of an input power in the 1 mm thickness of RAFM and Cu alloy

σ=Eε=EαΔT

Heat loading limit of RAFM steel and Cu alloy

RAFM cannot withstand under high heat load (Over ~75 MWm2) Cu alloy is almost sole solution of the divertor heat sink in the reactor

‐ TC30 WmK (RT)‐ E 200 GPa‐ 10 K

‐ TC 350 WmK (RT)‐ E 120 GPa‐ 165 K

E Youngs modulus [Pa] Thermal exp coeff [K‐1]

525

Over ~10 MWm2

Yield strengthYield strength

RAFM

High resistant to a neutron irradiationLow thermal conductivity

Cu alloy

Low resistant to a neutron irradiationHigh thermal conductivity

Cu alloys are low resistant to a neutron irradiation Can be available under the neutron loading

(a) Vertical cross‐section (b) Horizontal cross‐section Distribution of the fast neutron flux in FFHR‐d1 (gt01 MeV)

T Tanaka et al Fusion Eng Des 89 (2014) 1939

Acceptable value for a reactor running 625

We designed the divertor space located on the deep position surrounded by other wall components

~ 01dpayear

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Contents

425

Material selection for ldquoDivertorrdquo heat sink Required heat removal capability in the reactor divertor

0 5 10 15 200

200400600800

100012001400

Cu alloy

RAFM

t=1mm

Ther

mal

str

ess

[MPa

]

Input power [MWm2]

t=1mm

Induced internal thermal stress by a temperature gradient between surface and back surface as a function of an input power in the 1 mm thickness of RAFM and Cu alloy

σ=Eε=EαΔT

Heat loading limit of RAFM steel and Cu alloy

RAFM cannot withstand under high heat load (Over ~75 MWm2) Cu alloy is almost sole solution of the divertor heat sink in the reactor

‐ TC30 WmK (RT)‐ E 200 GPa‐ 10 K

‐ TC 350 WmK (RT)‐ E 120 GPa‐ 165 K

E Youngs modulus [Pa] Thermal exp coeff [K‐1]

525

Over ~10 MWm2

Yield strengthYield strength

RAFM

High resistant to a neutron irradiationLow thermal conductivity

Cu alloy

Low resistant to a neutron irradiationHigh thermal conductivity

Cu alloys are low resistant to a neutron irradiation Can be available under the neutron loading

(a) Vertical cross‐section (b) Horizontal cross‐section Distribution of the fast neutron flux in FFHR‐d1 (gt01 MeV)

T Tanaka et al Fusion Eng Des 89 (2014) 1939

Acceptable value for a reactor running 625

We designed the divertor space located on the deep position surrounded by other wall components

~ 01dpayear

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Material selection for ldquoDivertorrdquo heat sink Required heat removal capability in the reactor divertor

0 5 10 15 200

200400600800

100012001400

Cu alloy

RAFM

t=1mm

Ther

mal

str

ess

[MPa

]

Input power [MWm2]

t=1mm

Induced internal thermal stress by a temperature gradient between surface and back surface as a function of an input power in the 1 mm thickness of RAFM and Cu alloy

σ=Eε=EαΔT

Heat loading limit of RAFM steel and Cu alloy

RAFM cannot withstand under high heat load (Over ~75 MWm2) Cu alloy is almost sole solution of the divertor heat sink in the reactor

‐ TC30 WmK (RT)‐ E 200 GPa‐ 10 K

‐ TC 350 WmK (RT)‐ E 120 GPa‐ 165 K

E Youngs modulus [Pa] Thermal exp coeff [K‐1]

525

Over ~10 MWm2

Yield strengthYield strength

RAFM

High resistant to a neutron irradiationLow thermal conductivity

Cu alloy

Low resistant to a neutron irradiationHigh thermal conductivity

Cu alloys are low resistant to a neutron irradiation Can be available under the neutron loading

(a) Vertical cross‐section (b) Horizontal cross‐section Distribution of the fast neutron flux in FFHR‐d1 (gt01 MeV)

T Tanaka et al Fusion Eng Des 89 (2014) 1939

Acceptable value for a reactor running 625

We designed the divertor space located on the deep position surrounded by other wall components

~ 01dpayear

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Cu alloys are low resistant to a neutron irradiation Can be available under the neutron loading

(a) Vertical cross‐section (b) Horizontal cross‐section Distribution of the fast neutron flux in FFHR‐d1 (gt01 MeV)

T Tanaka et al Fusion Eng Des 89 (2014) 1939

Acceptable value for a reactor running 625

We designed the divertor space located on the deep position surrounded by other wall components

~ 01dpayear

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Selection of a suitable Cu alloy

SJ Zinkle et al Fusion Materials DOEER‐031316 (1994)

ODS-Cu (GlidCopreg) has a large advantage for high temperature toughness

eg GlidCopregODS‐Cu

eg CuCrZrPH‐Cu

Advantage for high temperature use

Softening occur above sim450˚C

725

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Divertor plasma

Divertor armour

HeatParticle

Divertor plasma

ODS‐Cu(GlidCopreg)

W

Candidate armour structure

Coolant

Required structure for heatparticle removal Divertor accepts not only high heat flux

but also high particle flux

~1024 ionm2s gt10MWm2HeatParticle

~1024 ionm2s gt10MWm2

BrazingorHIPODS‐Cu

(GlidCopreg)

825

Coolant

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Direct brazing between W and GlidCopreg

PH‐Cu(CuCrZr)

WIntermediate material (Cu)

Filler material

W

Conventional brazing(ITER case)

Advanced direct brazing(This study)

Filler material (BNi‐6)

ODS‐Cu(GlidCopreg)

Conditionhellip① Cu alloy ODS‐Cu (GlidCopreg)② Filler material BNi‐6 (Ni‐11P) with t=38 m thick

Important conditions for advanced direct brazing

60min 10min

960˚C860˚C

N2 Gas cooling

Natural cooling to 100 ˚C

(1)

(2)

(3)(1) Low brazing temperature(2) Short brazing time(3) Slow cooling rate (over 40h to RT)

①②

Optimized heat treatment can be used

925

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Brazing sample and mock-up successfully fabricated by advanced direct brazing technique

The small‐scale divertor mock‐up

Brazing samples with fine brazed layer

20mm

1mm

Brazed layer

GlidCopregW 1025

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Bonding layer has an enough toughness

Ductile fracture properties was able to be obtained Bonding layer obtained a toughness

GlidCopreg W

Bonding layer

Schematic view of the deformation

Before

After0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a) Room temperature

Results of the three point bending test

1125

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Bonding strength at high temperature

Strength does not decrease so much even at a high temperatureDuctility and toughness are increased

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

No 1No2

No3No4 No5

No6

025

(a)

0

50

100

150

200

Stre

ss [M

Pa]

Strain []

(b)

025

Room temperature

Toughness increased

1225

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

WBNi‐6GlidCopreg interlayer

Microstructural observation

20m

Fabricated by FIB

5m

Bonding layer

GlidCopregW

GlidCopregW

Extremely thin boding layer was successfully obtained

1325

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

0 3 6 9 12 150

100200300400500600700

Tem

pera

ture

[deg

]

Heat load [MWm2]

CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 water out water in

Heat removal capability of the divertor mock-up Heat loading test in ACT2

ANSYS simulation at 15MWm2 steady state

The design of the WBNi‐6GlidCopreg showed an excellent heat removal capability for using in the FFHR‐d1 divertor

CH2CH5CH7

Simulation

˚C

Parameters‐ Filler material 60 WmK (50m thick)‐ Water 25˚C (Thermal transferred from Cu)‐ W 03

ACT2

CH1CH2

CH3

CH4CH5

CH6CH7

CH8

1425

Water cooling parameters‐ Pressure 03 MPa‐ Flow rate 52 Lmin‐ Temperature 25˚C

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

E‐gun

Chamber

specificationsparameters value unitmax output power 300 (100) kWacceleration voltage 40 kV DCmax current 75 Amax scanning area 300 x 300 mmspot size of e‐beam 〜10 mm

Developed for evaluation of heat removal capability of actively cooled components

Focused electron beam was scanned desired area by deflection lenses

The device can apply steady state reactor relevant heat flux (~20 MWm2 50 x 50 mm2)

Electron gun JEBG‐3000UB manufactured by JEOL Ltd

High heat flux facilityACT2 Active Cooling Test-stand 2

1525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

bull Accelerated electron beam is focused as a Gaussian‐like profile (40 keV up to 75 A FWHM ~12 mm)

bull Target area is scanned by electro‐magnetic coils

(scan range 60 x 60 mm X 500 Hz Y 7143 Hz absorbed current 25 A on W)

(275‐28 MWm2 inside of the blue square)

Heat Flux distribution Temperature rise in scanning (calculation)

The beam profile(top) A melted spot of W irradiated for 01 s with 20 kW absorbed power (~200 MWm2 peak)(bottom)

Properties of the E-beam

1625By Y Hamaji

By Y Hamaji

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Tested surface is heated homogeneously Equipped diagnostics

thermocouples (x 8) pyrometer 400‐2000 calorimetry temperature difference between inlet and outlet water absorbed beam current

side view top view

heated area

spot sizetested unit

e‐ beam

thermocouples

Example of an Experimental Set-up

1725

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Contents

1825

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Large Helical Device LHD

Divertor Carbon

First wallStainless Steel (SUS316L)

External diameter 135 mPlasma major radius 39 mPlasma minor radius 06 mPlasma volume 30 m3

Magnetic field 3 T

Plasma facing componentsTotal area of PFCs 780m2

First wall panels SUS316L (~730m2) 95Divertor plates Graphite (~50m2) 5 1925

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

1m

(d)

Replacement position

(a)

Flaking dusts accumulated near the C divertor

(b)

5mm

(c)

000 100 200 300 400 500 600 700 800 900 1000

keV

1000

0

150

300

450

600

750

900

1050

1200

1350

Counts

CO

Fe

FeK

esc

FeFe

Mixed‐material of C and Fe

Dust formation issues C divertor

Cross‐sectional microstructure of the dust by TEM

Very fine stratified mixed‐material structure with C and Fe 2025

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Divertor tile（Isotropic graphite)

VPS‐W layer t=125m

The VPS-W with 125m thickness was coated on the IG tile

W‐Re multi layer

Replacement position

(a)

Flaky surface by C dust

(b)

Before campaign

ドーム下

W coated graphite divertor was installed

2125

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

(a)

(b)

Drastic improveldquoNo depositionrdquo

(c)

W coated graphite divertor

W coated divertor well worked for reduction of the flaking dust 2225

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

1cm

Melting and crack formation

Heat removal capability is not enough this structure 2325

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Direct brazing component of WGlidCopreg

has been currently developing

WGlidCopreg divertor is expected for

1 Excellent heat removal capability2 Reduction of the dust formation3 Low retention of the H isotope

2425

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525

Summary1 Development of the high heat flux component ldquoDivertorrdquo in fusion

reactor is one of the critical issues for realizing a fusion energy

2 The small divertor mock‐up of the WBNi‐6GlidCopreg was successfully developed in NIFS It showed an excellent heat removal capability Very thin bonding layer seems to contribute the excellent mechanical properties and heat removal capabilities

3 W coated graphite divertor tile was applied for demonstrating a reduction of the dust generation and a feasibility of the W coated surface Advantages of the W surface was demonstrated as a reduction of the dust formation

4 WGlidCopreg divertor has been developed to apply to the LHD experiment and towards a helical reactor

2525