PowerPoint

13th Apr. 2016
6th High Power Targetry Workshop
@Merton College
Present Status of Muon Production Target
at J-PARC/MLF/MUSE
J-PARC Center, MLF Division, Muon Section (KEK)
Shunsuke Makimura ([email protected])
Contents
1. Introduction
2. Muon Fixed & Rotating Target
3. Quality Assurance, case of rotating
target
4. Bad & Stupid examples
5. Summary
Instruction in 2003, 2004
 Gerd Heidenreich (Meson/ PSI)
 Jack Beveridge (Kaon/ TRIUMF)
Recent collaborations and discussions
 FNAL, BNL, PNNL, MSU, ORNL, ISIS , CERN,,,
Japan Proton Accelerator Research Complex
(J-PARC)
Materials and Life Science Experimental Facility
& MUON TARGET
S-Line; MuSR
H-line; G-2 experiment,
MuSEUM, DeeMe
3GeV-RCS
1MW in future
500kW at present
Muon Target
Neutron
Target
U-Line; Ultra Slow Muon
D-line; MuSR, Mu X-Ray
Materials and Life Science Experimental Facility (MLF)
The most intense pulsed muon beam all over the world
PSI; 1MW
Rotating Target
Rotating Target
Installation
ISIS/RAL; 200kW
Fixed Target
Country
LINAC Upgrade
New RCS
schedule
We are here
MR New PS
Earth
quake
Japan
Hadron
Acc.
U.K.
5Switzerland
Facilityat J-PARCJ-PARC
MUSEused forRAL
PSI
 The fixed target
had been
fiveISIS
years without
replacement.
P Intensity [MW]
1.0(Goal)
0.16
1.3
 The fixed target was replaced with rotating target in Sep. of 2014.
Surface target
Mu+ [/s]
x 107used
(U)@0.2MW
6 xwithout
105
3 x 107
 The rotating
has 6been
for two years
replacement.
DC / Pulse
Pulse (25Hz)
Pulse (50Hz)
DC
Muon Fixed Target (~2014 Sep.)
Isotropic Graphite
IG-430U (Toyo Tanso)
Diameter; 70mm
Thickness; 20mm
P-Beam diameter; 16 mm (2s)
4kW heat @ 1MW proton beam
70 mm
20 mm
Stainless steel pipe (Water)
Copper frame
Hot Iso-static Press method
Titanium layer
as stress absorber
Silver brazing method
It has been used for five years without
replacements. (accum. Beam 2500 MWh)
Muon Rotating Target (2014 Sep.~)
Learning from Paul Scherrer Institute,
Rotating target method is applied to
disperse the irradiation damage of
graphite to a wider area.
Solid lubricant; Disulfide tungsten
Aiming lifetime; 10 years
Rotating Target was successfully installed on 16th
September of 2014. Stable operation for two years!!
(Accumulated Beam power; 1000 MWh)
Proton beam
Fixed target
Rotating target
Remote handling of Muon Target
Residual radiation dose of muon target;
5 Sv/hour @surface
Non-destructive measurement of thermal conductivity
for 3-GeV p-irradiated muon target at J-PARC/MUSE
Thermal conductivity
70
Horizontal
pitch1mm
60
Themal conductivity (W/m/K)
Vertical
Pitch1mm
Transfer of Target by
Shielding vessel, cask
0.002dpa80℃
50
40
30
horizontal
20
vertical
10
0.25dpa200℃
0
-40 -30
-20 -10 0
10 20
distance from center (mm)
Un-irradiated
170W/m/K
30
40
Journal of Nuclear Materials 450 (2014) 110-116
Th. Cond. of beam spot; < 10 % of un-irradiated
Replacement in Hot cell
SiC/SiC and SiC coated graphite
(Near-Future development)
Grants-in-Aid for Scientific Research
KAKENHI Kiban B (16H03994)
Approved this April
Replacement of graphite with SiC/SiC composite
 MuSIC/RCNP at Osaka
 COMET Phase-I at Hadron Facility/ J-PARC
 (Muon Gr., G-2, DeeMe at MLF/J-PARC)
NITE-SiC/SiC composite material
By OASIS, Muroran Institute of Technology
CVD-SiC coated graphite
COMET Experiment by Dr. Mihara;
MuSIC/RCNP at Osaka Univ. by Dr. Sato
. Target is also located in capture solenoid.
Aiming Purpose
 Tritium barrier
for simple
maintenance
 High oxidation
resistance for air
introduction to
beam line
Active vs Passive
oxidation
BLIP-Irradiation at RaDIATE collaboration
Supported by US-JP collaboration of KEK
Representative; T. Ishida, and P.Hurf
Quality Assurance, case of rotating target
J-PARC has no in-house manufacturing division.
In general, a large apparatus is fabricated by a vendor.
To fabricate the apparatus, we must know
“what specification we actually need”
with consideration for
performance (design, mechanics, material,,,)
facility (utilities, environment, handling device,,)
feasibility, maintenance, cost, schedule, manpower,,,,,
Impossible to mimic conditions of proton irradiation
Muon Group
Conceptual
Design and
mock-up test
Conceptual
design
Detailed
design &
fabrication
of mock-up
Test by
mock-up
Fabrication
of actual
target
Vendor, Manufacturer
Specification
Document
for bidding
Subcontractor
On-site
inspection
Subcontractor
Durability tests by mock-up
Heating & Rotating tests
750 degC max. (650 degC @B.L.)
300 r.p.m. (15 r.p.m. @B.L.)
330 mm
Proton
beam
Heating test
(x 10 %)
torque
モータートルク（×10%）
6
モータートルク
Motor torque
(x 10 %)
5
4
Bearings was damaged very
quickly even with disulfide
tungsten lubricants.
3
2
1
0
-1
03/04 7:12
03/05 19:12
03/07 7:12
03/08 19:12
03/10 7:12
03/11 19:12
Difference of thermal expansion
between vertical shaft and shaft support
One-sided damage was observed on the
disassembled bearing (Fixed bearing).
coupling
Spline nut
Magnetic coupling
Coupling
Transmission of rotation, but free motion
in axial direction, THK co., LTD.
Fixed bearing (axial dir.)
Pass-through bearing
Motor torque (x 10 %)
Operation for 4 days
9 days with 300 r.p.m.
(4800h @15 r.p.m.)
Operation for 5 days
It will work at least for 1 year!!
Actually, it has been used for two years.
The other testing by mock-up and modification
Appearance test of surface of bevel
gears by SEM
Modification of up-down motion system
Distortion check by dimensional
test before and after heating
Introduction of radiation-hard grease
to magnetic coupling
Bad & Stupid examples of quality assurance
2007; Disassembling of cask and
measurement of dimension again
Skip of on-site inspection for
dimensional check
2006; Scratch on pillowseal
Forgetting of distortion of
vacuum duct by air-pressure load
2006~2015; Unprecise
measurement of
temperature on scraper
Forgetting of thermal
radiation from rotating
target
In 2014, we found it.
1.5 Sv/h replacement
Matoba will report it.
Summary
Since 2008, stable operation by fixed target
and rotating target has been performed.
It has been achieved on continuous upgrade
against many failures.
We must keep the spiral upgrade continuously.
Matoba will give a talk in session 5 tomorrow,
for our Monitoring (temperature, sounds,,)
Thank you for your attention and see you
again in next HPTW.
Bearing & Solid lubricants
For our target, the bearing is used under 100 MGy/year, 400 Kelvins, 10-5 Pa
Type
Temp.
(Kelvins)
Pressure
(Pa)
Radiation
Speed
(rpm)
Storage
Lifetime
@15rpm
(hour)
MoS2
coating
<570
105 to 10-5
general
<500
air
1100
Ag
coating
<600
10-3 to 10-10
general
<500
vacuum
5800
WS2
Separator
<600
105 to 10-5
few
<210
air
110000
Retainer, balls, &
rings, coated by
MoS2 or Silver
Separator made
of sintered
compact of
WS2
Great amount of Lubricant
Captured from
JTEKT(KOYO) Catalog
Evaluation by the formula
of the JTEKT Catalog
Disulfide Tungsten is used for MUSE target.
Anticipated Lifetime is 20 years!!
Radiation resistance of WS2 should be confirmed.
Radiation Resistance of WS2
Electron beam irradiation
JAEA, Takasaki,
2MV, 1mA, 20hours, 100MGy
Durability tests with load & heat
4.5 million revolutions,
1year@ beam line
No irradiation effect was observed.
Analysis of rotating target
Analysis of ordinal operation by FEM on ANSYS & Finite
Difference Method on Microsoft Excel
Maximum temp. 920 Kelvins, Difference; 80 Kelvins
Thermal stress ;3MPa
Rotation speed at beam line should be 15 rpm.
30th July, 2014
Replacement of the used Fixed target
M2 line
M1 line
Radiation dose;
750μSv/h @12 m
(150mSv/h
@30cm）
To neutron
source
Remote-controlled camera
No crack was observed.
400 mSv/h @20cm
Dose-meter & Digital camera
10cm
gap
7th July, 2014
FL4m
Transportation to
tentative storage
vessel
Cooling
Jacket
Operation of muon rotating target
300-kW & 400-kW operation for 3 months
600-kW operations for 1 hour on 8th Apr./2015
Continuous 500-kW operation
Motor torque has been remaining constant.
Trial tests for
interlock in case
of beam
stopping
Horizontal
shaft
Bearing
Proton
beam
Thermocouples for
shaft temp.
Graphite
wheel
Graphite temperature by thermal radiation
300kW
500kW
1MW
Shaft (Simulation)
71 degC
84 degC
112 degC
Shaft (Measurement)
78 degC
95 degC
-
Graphite (Simulation)
400 degC
475 degC
Th. radiation (Measurement)
45 degC
60 degC
620 degC
-
The Others
Bevel gear for
rotation of target
Bearing of rotation F.T.
Thermal expansion
To-be-installed
Rotating Target
Rotation
shaft
Heavy shielding
Bearing of which inner ring is fixed to shaft.
Target rod
Bearing
(not fixed)
Top
coupling
THK spline nuts DP15
Coupling
Absorption of thermal
expansion of the long shaft
Completed!!
Spline nut
Remote-controlled
commissioning at Hot cell
Regular maintenance for Rotating Target
 Aiming lifetime; 10 years, Possibilities of breakdown
 Lifetime of some components in maintenance
area; Several years (Replacement by regular
maintenance)
1. Components, which can not be replaced easily.
 Most of Bearings in vacuum & Coupling
 Target itself
Lifetime; > 10 years
2. Components, which can be replaced in
maintenance area (out of vacuum)
 Motor for rotation, motor for up-down
 Timing belt for up-down motion Lifetime; 2~3years
3. Components, which can be replaced in
maintenance area (in vacuum)
 Magnetic coupling FT for Rotation introduction
into vacuum
 Coupling. Bearing with the heaviest load
Lifetime; 2~3years
Rotating Target
 Suppression of thermal conduction from Graphite
to bearings
 3 Pieces of graphite are integrated to a wheel by
centrifugal rings.
 Thin flat bars will absorb the thermal expansion
between CF ring and outer ring of target support.
They must support weight and inertia of the
graphite.
Items to be considered for multi-MW target
 Maximum temperature of bearing, graphite
 Thermal stress on graphite and the flat bars
Target
support
Cooling jacket (Cu)
Graphite
Bearing
Chamber
Temperature & Thermal stress on graphite
 Adiabatic heating by pulsed beam
Thermal stress; 0.8MPa @1MW
Strength; 10 MPa (assumption)
10 MW can be accepted.
Beam spot
Diameter; 16mm
Beam loss; 3500W (1MW)
 Temperature & Thermal stress by quasi-static
heating on graphite (With rotation)
 Temperature difference VS Thermal stress
on graphite
3MPa @100 degC
10MPa @330 degC
Limitation of temp. difference (assumption);
330 degC
Temp. difference;
80 degC @1MW, 120 degC @2MW,
280 degC @5MW
Simulation by FEM &
finite difference method
5 MW can be accepted.
 Limitation of temp. 1600 degC
(Evaporation rate in Vac.)
650 degC @1MW, 840 degC @2MW,
1150 degC @5MW
5 MW can be accepted.
Fatigue property of IG-110
JAERI-M-84-148
Thermal stress on bearing & flat bar
 Temperature at bearing
Limitation of temp. (assumption);
Space between rings and balls; 150 degC
By Re-design of bearing, limitation will be 300
degC.
120 degC @1MW, 155 degC @2MW,
235 degC@5MW
2MW can be accepted by the current target.
5MW can be accepted by a replaced target with
re-design of bearings.
 Thermal stress on flat bar
Limitation of temp. difference(assumption);
200MPa @350 degC, inconel strength
110 degC @1MW, 125 degC @2MW,
135 degC@5MW
5MW can be accepted by the current target.
As far as the target itself is concerned, 2MW can be accepted by the
current target. And 5MW can be also, with re-design of bearing.
Detection of cracks
Analysis of severe crack model
Max. temp.; 1480 degC
Actually, the sensitive monitoring has been
achieved. The offset of the beam position can
be monitored by the unbalance of the
diagonal temperature .
Cracks can be observed, through observation
of diagonal thermo-couples,
①
right
left
Temperature difference at T.C. ; 7.2 degC
It is larger than the actual temp. difference.
49
47
45
43
left
41
right
39
③
37
35
0
5
⑦
3
⑤
2
Actual temperature difference at T.C.@ RUN47 ; 2.2 degC
4mm offset; Beam position Down-Left
10
15
20
T1-T5 with calibration
T3-T7 with caribration
1
0
-1
-2
-3
0
2000
4000
6000
8000
10000
12000
1mm/month
Isotropic Graphite
0.001mm/month
Isotropic graphite
(polycrystalline graphite)
2000 degC
1600 degC
⇔Highly Ordered Pyrolytic Graphite (HOPG)
140
thermal conductivity(W/mK)
 For accelerator, nuclear reactor
 Low density
 High resistance to heat
 Low Young’s modulus
 High strength
 Low residual radiation
IG-430U (Toyo Tanso); Muon Target
(IG-110; irradiation data obtained
systematically)
Evaporation rate of graphite
（M.S. Avilov et al., Nuclear Instruments and
Methods, A618 (2010) 1）
0.02dpa 200℃
0.25dpa 200℃
0.82dpa 400℃
unirradiated
120
100
80
60
40
20
0
0
200
400
600
800
1000 1200 1400 1600
temperature(℃)
Neutron irradiation effect to thermal conductivity
(T. Maruyama et al., Journal of Nuclear Materials
195 (1992) 44-50.)
Irradiation effect to thermal conductivity
Dimensional change by proton irradiation
 HOPG (Highly Oriented Pyrolytic Graphite)
c-axis; expansion, a-axis; shrinkage (expansion > shrinkage)
(B. T. Kelly et al., Phil. Trans. A, 260 (1966) 37-49.)
 Isotropic Graphite
Pore closure, Pore growth, Crystal growth
No effect was
observed under
2300 K without
irradiation.
(G. B. Neighbour, J. Phys. D: Appl. Phys. 33 (2000) 2966-2972)
Gradient; Dimensional
change rate (%/dpa)
Dimensional change (%)
temp. dependence
Expansion (< 300 degC <), Shrinkage
http://www.toyotanso.co.jp/Products/Pruduct_j.pdf
Radiation damage (dpa)
Proportional to rad.
damage in our case.
Dimensional change rate
(%/dpa) depends on
temperature.
G. B. Neighbour
Radiation damage (dpa) – Dimensional change(%)
Measurement for thermal conductivity of graphite
Thermal diffusivity are measured instead of Th. conductivity.
l=Drc (l; Th. Conductivity(W/m/K), D; Th. diffusivity(m2/s), r; Density (kg/m3), c; Th. Capacity (J/kg/K))
Conventional Method
(Laser-flash technique)
New method for this experiment
Laser Spot Heating technique
2-dimensional
thermo-meter
Cutting of
specimen
Measurement
Temp.@
Heated
spot
time
Temp. @
Mating
surface
time
Delay of
transmission
The target must be destroyed.
We must consider transportation and
the scattered radioactive powders.
The spatial resolution is limited by
sample size.
Periodic heating
Diode Laser
Non-destructively
Target can be used again.
Decreasing nucl. wastes
High spatial resolution
Modified Thermal Imaging Scope
(Bethel. Co. LTD.)
Comparison
of Amplitude
Temp. variation
@ Heated spot
time
Temp. variation
@distant position
from heated spot
time
Delay of transmission; q
(H. Kato et al., Meas. Sci. Technol. 12 (2001) 2074-2080)
Theoretical Background of this technique
Thermal transport equation
D; Th. diffusivity(m2/s), r; Density (kg/m3), c; Th. Capacity (J/kg/K))
P
T (r , t ) 
exp( kr  i ( wt  kr))
4Drc
q
Amplitude
k

2D

f
D
l
-1
Carslaw H S and Jaeger J C 1959 Conduction of Heat in Solids (Oxford: Clarendon)p 263
q
r
q
r
Periodic heating on Point
Pexp(it)

gradient
f
Thermo-meter
Distribution of Th. Cond.
must be measured.
D
Amplitude includes
given heat by laser, P
r
Comparison
of Amplitude
Temp. variation
@ Heated spot
time
Temp. variation
@distant position
from heated spot
time
Delay of transmission; q
Feasibility of Apparatus
DT; about 5 K
2-dimensional infrared
thermo-meter
Expensive!!
Evaluation by Delay
High quantitative performance
Evaluation by Amplitude
Low quantitative per., but low costs
Relative measurements based on an
exact Th. Cond., obtained by other
technique (Laser flash method).
Un-irradiated Th. Cond. 170W/m/K
Measuring Apparatus of thermal conductivity
Vicinity of Muon Target; 5Sv/h, 5Gy/h for organic material (by Kawamura)
Assumption; Lifetime of measuring device, 100Gy, this means 20 hours
50mm iron shielding decreases the dose to 20 %. Extended Lifetime; 100 hours
Measurements with mirror reflection
Laser spot heating
apparatus
Integrated measuring apparatus
is set on a three-dimensional
movable stage, which is set on
plug stand.
Relative position is confirmed by
laser displacement meter.
Muon Target will set
on the plug stand
mirror
Laser displacement meter; resolution 1mm
CCD camera
Shielding for radiation
2-dimensional
Thermo-meter
Periodic
Heating LD
Laser spot heating apparatus
Indirect measurement
through mirror reflection
The devices are set on the 3dimensional motion stage.
Position resolution; 10mm
Beam Profile and Anticipated Th. Conductivity
The variation of thermal conductivity
irradiated by neutrons
20mm x 16mm
Map pitch2mm
Horizontal
pitch1mm
Vertical
Pitch1mm
Beam density(MWh/mm^2)
Distribution of Beam density (~RUN39)
-20
8
Max. 0.25dpa
6
thermal conductivity(W/mK)
Annealing effect
140
0.02dpa 200℃
120
0.25dpa 200℃
100
0.82dpa 400℃
80
unirradiated
60
40
20
0
0
4
Vertical
2
Horizontal
0
-10
0
10
Distance from center (mm)
200
400
600
800 1000 1200 1400 1600
temperature(℃)
Data for IG110
T.Maruyama et al., Journal of Nuclear
Materials 195 (1992) 44-50.
20
0.002 dpa
If decrement of conductivity is proportional
to radiation dose, the distribution for the
thermal conductivity corresponds to the
beam profile.
From Simulation
Th. Conductivity can be anticipated,
0.25dpa on center 200degC; 5W/m/K
0.002dpa on edge 80degC; 10W/m/K
Measurement in Hot cell
20mm x 16mm
Map pitch2mm
Results
We could observe an annealing effect on the center of beam
spot because of high temperature.
The beam profile for horizontal/vertical could be observed.
Thermal conductivity was higher than the prediction.
Total
(Horizontal)
Total
(Vertical)
-35 -30 -25 -20 -15 -10 -5
0
5 10 15 20 25 30 35
Thermal conductivity
70
0.002dpa80℃
Themal conductivity (W/m/K)
60
50
40
30
horizontal
20
10
vertical
0.25dpa200℃
0
-40 -30
-20 -10 0
10 20
distance from center (mm)
Un-irradiated
170W/m/K
30
40
Vertical
Pitch1mm
Rad. Dose
(dpa)
Th.Cond.
Prediction
Th.Cond.
Results
Center of
target
0.25
5 W/m/K
15 W/m/K
Edge of
target
0.002
Ellipse shape
Beam Loss (a.u.)
Total Beam Loss on Target
Horizontal
pitch1mm
(200 degC)
(80 degC)
15W/m/K 50 W/m/K
Results
(Mapping)
Ellipse shape
Beam Loss (a.u.)
Total Beam Loss on Target
-35 -30 -25 -20 -15 -10 -5
Total
(Horizontal)
Total
(Vertical)
0
5 10 15 20 25 30 35
2-dimensional map of thermal conductivity
20mm x 16mm
Map pitch2mm
6
4
2
0
-2
-4
-6
-8
10 8 6 4 2 0 -2 -4 -6 -8 -10
Horizontal - distance from center (mm)
Vertical - distance from center (mm)
8
54-56
50-54
46-50
42-46
38-42
34-38
30-34
26-30
22-26
18-22
14-18
10-14
Muon/Pion Production Target
for proton accelerator in Japan
MuSIC at Osaka/RCNP
J-PARC
New DC muon source,
392MeV, 400 W
Ref. A. Sato @Osaka Univ.
MLF/Muon
3 GeV, 1MW
by S. Makimura
COMET Phase 1
(Plan)
8 GeV, 3.2 kW
Ref. S. Mihara
G10 mock-up
Neutrino (T2K)
30 GeV, 1 MW
Ref. T. Nakadaira
Graphite Target in general
From t2k experiment.org
Polycrystalline Graphite
Conventional material for High Power Proton Target
 Not only Japan but also, PSI, ISIS,,,,
 Low density~ Low Beam loss
Large disperse of muon/pion production
 High-temperature resistance
 Low Young’s modulus~ Low thermal stress
 High thermal-shock resistance
 Loss by Oxidation
 Tritium Production
SiC/SiC composite material
Candidate of new target material with High Performance
Advantage of SiC with regard to Physics requirements
COMET Experiment;
Pion Production Target
Capture Solenoid
These information were supplied by Dr. Mihara.
Muon-Electron Conversion
Hadron Experimental Facility at J-PARC
 Phase-I; 8 GeV-MR, 3.2 kW, Graphite target
 Phase-II; 8 GeV-MR, 56 kW, High-Z target
Muon Transport Section is designed for Phase-II.
To reduce the disperse of muon production in
the solenoid, SiC target is preferable to graphite
for Phase-I.
Under discussion, with Dr. Mihara.
MuSIC/RCNP at Osaka Univ. by Dr. Sato
Target is also located in capture solenoid.
Advantage of SiC with regard to Physics requirements
DeeMe Experiment;
These information were supplied by Dr. Aoki in
Osaka Univ..
Si nucleus
→ DeeMe
Graphite (C) → Si: 11-times larger overlap
μ- reaction ε: 8%(C)→67%(Si)
C nucleus
Muon-Electron Conversion
Materials and Life Science Facility at J-PARC
 Sensitivity of DeeMe; 10 -14
 (Sensitivity of COMET
Phase-I; 10-15, Phase-II; 10-17 )
Better to replace graphite with SiC.
μ-(Si)
μ-(C)
r/aBohr
Silicon Carbide
Eff. of Muon Reaction: 6 times larger than
graphite.
Concept of DeeMe, simple, quick and low-cost.
Collaboration with Muroran Institute of Technology
R&D for J-PARC/MLF Target is in progress. Talk by Dr. Kishimoto
Interest in RaDIATE
 Information sharing about proton & neutron
irradiation of SiC and SiC/SiC composite.
 Irradiation test by BLIP?
(Budget is limited, because the actual collaboration is
just started now.)
“Silicon Carbide” vs “Graphite”
Density (Beam loss)
Young’s modulus
Bending Strength
Graphite (IG-430)
1.82 g/cc (4kW)
11 GPa
45 MPa
SiC (SC1000, Kyocera)
3.2 g/cc (8 kW)
440 GPa
450 MPa
Comparison with graphite (Very rough discussion)
Thermal stress depends on Product of temperature (2 times)
and Young’s modulus (40 times).
“Thermal stress; 80 times” VS “Strength; 10 times”
SiC has 8 times larger risk than graphite about thermal stress.
Thermal stress by quasi-static temperature
distribution (DC beam)
Thermal stress by adiabatic pulsed-heating
“Material Properties of Silicon Carbide”
(In parentheses, Graphite)
 Density; 3.2 g/cc (1.82 g/cc)
 Heat generation by proton beam; 8kW (4kW), 2 times larger than Graphite
 Thermal Conductivity; 200W/m/K @ R.T.
(130W/m/K @R.T., 50W/m/K @1000℃)
In our case, radiation damage must be considered; 20W/m/K (15 W/m/K)
 Upper temperature limit;
2000℃ (1700 ℃) on the viewpoint of vacuum, 1300℃ in the air
1000 ℃ on the v.p. of heavy radiation damage, dislocation loop
 Bending Strength; 450MPa (45MPa), 10 times larger than Graphite.
(By radiation damage; 350MPa @4dpa 500 degC
280MPa @25dpa 800 degC for typical sintering material [1])
 Young’s Modulus; 440GPa (11GPa), 40 times larger than Graphite.
 Emissivity；0.8-0.9 (0.94; calibrated by T.C.)
[1] G.W. Hollenberg et al. Journal of Nuclear Materials 219 (1995) 70-86
Thermal stress depends on Young’s modulus x Heat
“10 times Strength” vs “80 times Thermal stress”
For thermal stress, 8 times larger risk than Graphite.
Thermal stress by temperature distribution
Mises stress; 109 MPa
Max. temp.; 1050 K
Heating test on Aug. 6th
Tensile stress; 190 MPa
108 MPa
due to releasing the constraint by removing outer SiC.
 Improvements to reduce the thermal stress are in progress.
Thermal stress by adiabatic pulsed-heating
Thermal stress is generated by adiabatic pulsed heating
with constant volume.
Assumption
8 kW, 25Hz, Beam diameter; 14 mm (uniform)
Beam spot
E; Young’s modulus 440 GPa
Α; Th. Expansion 4.3 ppm/K
Ρ; Poisson ratio 0.16
C; 700 ( J/kg/K) @300K
1300 @1300K
DT; 93 K @300 K, 50 K @1300 K
25Hz, 15000 hours (1.3×109 ) thermal stress;
220 MPa @300 K, 170 MPa @1300 K
(Bending strength; 450 MPa)
Severe conditions on the viewpoint of Fracture toughness, brittleness
Developments of material itself are required.
SiC/SiC composite material by OASIS Gr. in Muroran
Institute of Technology
SiC Development History as a Nuclear Material
 Development of SiC as a
nuclear material started in
80s.
 SiC/SiC is the most potential
candidate of structural
material of fusion reactors in
future.
 Radiation damages on SiC
have been researched using
fission reactors and many
kinds of ion accelerators.
 Especially, synergistic effects
• ‘Blackof
spots’
are probably small
displacement
damages
loops or SIA
cluster as loop
embryo.
and gas atoms have been
• Perfect loops develop into
dislocation
network at high
revealed
byT dual-ion
and high doses.
• Microstructural
developmentresearches.
in
irradiation
the high-T & high-dose regime is
to some of fccreinforced
metals.
similarSiC/SiC
by highly
crystallized SiC fibers
Fluence (dpa)
represents excellent
Ion irradiation researches and microstructural characterization
revealed the irradiation damage tolerance of SiC as a fusion
irradiation resistance
Irradiation Temperature (°C)
HPCFI: High Performance Composite Materials for Future Industries
AMG: Advanced Materials Gas-Generator
CREST-ACE: Core Research for Evolutional Science and Technology-Advanced materials for Conversion of Energy
IVNET: Innovative Nuclear Energy Technology development
SIPSAM: Support Industry Program/SiC/SiC for Al Die-Casting Machine by Hot-Chamber Method
SIRIUS: SiC Integration Research for Innovative Utilization of Geothermal Energy Source
SCARLET: SiC Fuel Cladding/Assembly Research Launching Extra-Safe Technology
1
1
INSPIRE: Innovative SiC Fuel-Pin Research
i
i
i
i
FIAT: LWR Fuel with Increased Accident Tolerance
1400
i
1
Larger Loops
Dislocation Network
Voids
1
1200
i
i
3
3
i
1000
i
1
i
800
1
600
i
1
1
n
n
i
BSD + Small Loops
5
1
i
i
2
i
material
1
2
n : This work, neutron
i : This work, self ion
1: Price (1973)
2: Yano (1998)
3: Senor (2003)
4: Iseki (1990)
BSD
n
Advanced SiC/SiC (red line) keeps flexural strength
after neutron irradiation in fission reactor
i
Frank Loops
i
400
200
i
10
100
Black Spot Defects (BSD)
Small / Frank Loops
Large Loops
Dislocation Network
Voids
SiC/SiC Composite (NITE & NIC SiC)
SiC/SiC claddings
Possibility to introduce SiC/SiC for muon target
Advanced materials developed for nuclear & fusion
reactor by OASIS Group of Muroran Institute of
Technology. Collaboration is in progress.
Irradiation tests in
 FEEMA Project at OASIS
Halden reactor, Norway
 Support program at KEK
(Kasokuki Shien Jigyo) (2014, 2015)
 Workshop at J-PARC
last September
SiC workshop at J-PARC (J-PARC News No. 126)
High thermal conductivity (controllable)
Large and Complex Shapes
Excellent Mechanical Properties (Strength
or Pseudo-ductility, Young’s modulus)
Excellent Radiation Resistance anticipated
1/3 model for muon target
It can be also applied for accelerator field.

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