december 12-13, 2007/arr 1 power core engineering: design updates and trade-off studies a. rené...

December 12-13, 2007/ARR1

Power Core Engineering: Design Updates and Trade-Off Studies

A. René Raffray

University of California, San Diego

ARIES MeetingGeorgia Tech., Atlanta, GA

December 12-13, 2007


Engineering and Trade-Off Studies• Power cycle choice: Rankine vs Brayton (done, UCSD)

• Impact of tritium breeding requirement on fuel management and control (done, UW/UCSD)

• Evaluation of different He-cooled divertor concepts based on thermo-mechanical performance and initial reliability assessment (in progress, UCSD/INL/Georgia Tech.)

• Assessment of off-normal conditions for a power plant- how to avoid disruptions and other off-normal events (in progress, GA)- impact of off-normal events on power plant (thermal impact presented here,

UCSD)

• Impact of design choice on reliability, availability and maintenance (L. Waganer)

• Lead lithium based blanket as example development pathway (DCLL design updates and discussion at this meeting)


Vapor Pressure and Heat of Dissociation of SiC

Si Vapor Pressure as a function of Temperature

y = 4E-111x 33.741

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

0 500 1000 1500 2000 2500

Temperature (K)

Vapor Pressure (Pa)

Series1

Power (Series1)

Heat of sublimation of Si = 454 kJ/mol (108.4 kcal-mol-1)

(from S. G. Davis, et al., Journal of Chemical Physics, Vol. 34, No. 2, p659-663, Feb 1961)

Heat of formation of SiC = 62.85 kJ/mol (15 kcal-mol-1)Heat of dissociation of SiC = 516.9 kJ/molSi melting point/boiling point= 1412°C/2355°CC sublimation point >3500°C


SiC DissociationSiC Dissociation erosion as a function of temperaturey = 3.0675E-

70x2.7897E+01 y = 2.3489E-

26x1.4971E+01

1.000E+18

1.000E+19

1.000E+20

1.000E+21

1.000E+22

1.000E+23

1.000E+24

1.000E+25

1.000E+26

1.000E+27

1.000E+28

1.000E+29

1.000E+30

1.000E+03

1.500E+03

2.000E+03

2.500E+03

3.000E+03

3.500E+03

4.000E+03

4.500E+03

5.000E+03

Temperature (K)

Sublimation erosion (particles/m2-

s)

Series1

Series2

Series3

Power (Series2)

Power (Series3)

SiC Dissociation q'' as a function of temperaturey = 2.6337E-

88x2.7897E+01 y = 2.0166E-

44x1.4971E+01

1.000E+00

1.000E+01

1.000E+02

1.000E+03

1.000E+04

1.000E+05

1.000E+06

1.000E+07

1.000E+08

1.000E+09

1.000E+10

1.000E+11

1.000E+12

1.000E+03

1.500E+03

2.000E+03

2.500E+03

3.000E+03

3.500E+03

4.000E+03

4.500E+03

5.000E+03

Temperature (K)

Sublimation q'' (W/m2)

Series1

Series2

Series3

Power (Series2)

Power (Series3)

• Example SiC armor case assumed here based on ARIES-AT

• However, not clear whether SiC armor is acceptable based on C erosion and T co-deposition

• W layer might be needed on SiCf/SiC


Off-Normal Thermal Loads for Analysis with RACLETTE Code

From ITER (from PID and C. Lowry’s presentation at last ITER WG8 Design review Meeting)

• Disruptions:– Parallel energy density for thermal quench = 28-45 MJ/m2 near X-point– Deposition time ~ 1-3 ms– Perpendicular energy deposition will be lower, depending on incidence angle (at least 1 order

of magnitude lower)– Parallel energy deposition for current quench = 2.5 MJ/m2

- For power plant, fusion energy is ~ 4x higher than ITER and the energy deposition will also be higher

- Parametric analysis over 1-10 MJ/m2 and 1-3 ms

• VDE’s:– Energy deposition = 60 MJ/m2

– Deposition time ~ 0.2 s

• ELMS:– Parallel energy density for thermal quench (controlled/uncontrolled) ~ 0.77/3.8 MJ/m2

– Deposition time ~ 0.4 ms– Frequency (controlled/uncontrolled) = 4/1 Hz- Assumed power plant case ~0.3/1.5 MJ/m2 incident energy deposition over 0.4 ms


Example Disruption Case for Power Plant with SiC FW

500

1000

1500

2000

2500

3000

3500

0.00 0.02 0.04 0.06 0.08 0.10 0.12

Time (s)

Temperature (°C)

Tmax,SiC

Tcool

• Disruption simulation: q''=109 W/m2 over 3 ms (~3 MJ/m2)• 1 mm CVD SiC armor on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K

SiC Evaporated Layer

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.0E-04 1.0E-03 1.0E-02 1.0E-01

Time (s)

SiC Phase Change Thickness (m)


4-mm SiCf/SiC1-mm CVD SiC

Pb-17Lih = 5 kW/m2-KT = 830°C

Energy Deposition


Parametric Study of Maximum SiC FW Temperature for Different Disruption Scenarios

• 1 mm armor (CVD SiC) on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K

Maximum SiC Armor Temperature as a Function of Energy Density for Example Disruption Case over Deposition Times of 1 and 3 ms

1500

2000

2500

3000

3500

4000

0 2 4 6 8 10

Energy Density (MJ/m2)

Maximum Temperature (°C)

1 ms3msPoly. (1 ms)Poly. (3ms)


Parametric Study of Maximum Sublimation Thickness of a SiC FW Temperature for Different Disruption Scenarios

• 1 mm armor (CVD SiC) on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K• Up to ~0.1 mm lost per event• Ony a few events allowable based on erosion lifetime

Maximum SiC Armor Sublimation Thickness as a Function of Energy Density for Example Disruption Case over Deposition Times of 1 and 3 ms

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

0 1 2 3 4 5 6


Sublimation Thickness (m)

Evap. for 1 ms

Evap. for 3ms

Poly. (Evap. for 1 ms)

Poly. (Evap. for 3ms)


Parametric Study of Maximum W FW Temperature for Different Disruption Scenarios

• 1 mm armor (W) on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K• W MP = 3422°C; BP = 5555°C

Maximum W Armor Temperature as a Function of Energy Density for Example Disruption Case over Deposition Times of 1 and 3 ms

0

1000

2000

3000

4000

5000

6000

7000

0 1 2 3 4 5 6


Maximum Temperature (°C)

1 ms3msPoly. (1 ms)Poly. (3ms)


Parametric Study of Maximum Phase Change Thickness of a W FW Temperature for Different Disruption Scenarios

• 1 mm armor (W) on 4-mm SiCf/SiC FW cooled by Pb-17Li at 830°C with h=5 kW/m2-K• Up to ~0.1 mm melt layer and ~0.01 mm evaporation loss per event• Again, only a few events allowable based on erosion lifetime

Maximum W Armor Phase Change Thickness as a Function of Energy Density for Example Disruption Case over Deposition Times of 1 and 3 ms

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

0 1 2 3 4 5 6


Maximum Phase Change

Thickness (m)

Evap. for 1 ms

Evap. for 3ms

Melt for 1 ms

Melt for 3 ms

Poly. (Evap. for 1 ms)

Poly. (Evap. for 3ms)


Parametric Study of Maximum Phase Change Thickness of a W FW Temperature for Different Disruption Scenarios (DCLL Case)

• 1 mm armor (W) on 4-mm FS FW cooled by He at 483°C with h=5.2 kW/m2-K• Up to ~0.1 mm melt layer and ~0.01 mm evaporation loss per event• Again, only a few events allowable based on erosion lifetime depending on energy density

Maximum W Armor Phase Change Thickness as a Function of Energy Density for Example Disruption Case over Deposition Times of 1 and 3 ms (ARIES-CS,

DCLL, He T = 483°C)

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

0 1 2 3 4 5 6


Maximum Phase

Change Thickness (m) Evap (DCLL) for 3msMelt (DCLL) for 3 msEvap (DCLL) for 1 msMelt (DCLL) for 1 msPoly. (Evap (DCLL) for 1 ms)Poly. (Evap (DCLL) for 3ms)

4-mm FS1-mm W

Heh = 5 kW/m2-KT = 480°C

Energy Deposition


Example VDE Case for Power Plant with SiC FW• VDE simulation: q''= 3 x 108 W/m2 over 0.2 s (60 MJ/m2)• 1 mm CVD SiC armor on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K• Even 1 event is not acceptable (complete loss of armor)• Same conclusion for W armor

500

1000

1500

2000

2500

3000

3500

4000

4500

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09

Time (s)

Temperature (°C)

Tmax,SiC

Tcool


1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00

Time (s)




Example Uncontrolled ELM Case for Power Plant with SiC FW

• ELM simulation: q''= 3.75 x 109 W/m2 over 0.4 ms (1.5 MJ/m2)• 1 mm CVD SiC armor on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K• ~0.02 mm of armor loss per event (1 Hz frequency)• Not acceptable (complete loss of armor after 50 such events)• Similar conclusion for W armor

- Tmax= 5512°C; 5x10-5 m melt; 3x10-7 m evaporation loss per event - Complete loss of armor after 3333 such events even without melt loss

500

1000

1500

2000

2500

3000

3500

4000

4500

0.00 0.00 0.00 0.01 0.01 0.01 0.01

Time (s)

Temperature (°C)

Tmax,SiC

Tcool


1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00

Time (s)




Example Controlled ELM Case for Power Plant with SiC FW

• ELM simulation: q''= 7.5 x 108 W/m2 over 0.4 ms (0.3 MJ/m2)• 1 mm CVD SiC armor on 4-mm SiCf/SiC FW by Pb-17Li at 830°C with h=5 kW/m2-K• ~0.08 m of armor loss per event (5 Hz frequency)• Complete loss of SiC armor after 1.25x107 such events (~1 month if occurring at same location) - Not acceptable• OK for W armor (Tmax=1872°C; no melt; 10-20 m evaporation loss per event)

500

1000

1500

2000

2500

3000

3500

4000

4500

0.00 0.00 0.00 0.01 0.01 0.01 0.01

Time (s)

Temperature (°C)

Tmax,SiC

Tcool


1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00

Time (s)




Summary of Assessment of Off-Normal Energy Deposition on FW

(based on assumed scenarios)• Focus on thermal effects

• EM effects will be important for DCLL but not as much for ARIES-AT with resistive FW (SiCf/SiC)

• Only a few disruptions can be accommodated (depending on the energy density)

• DCLL slightly better than ARIES-AT (because of lower base temperature of FW)

• VDE cannot be accommodated

• Only limited number of uncontrolled ELM cases can be accommodated

• Controlled ELM’s would limit the lifetime of SiC armor but might be acceptable for W armor

december 12-13, 2007/arr 1 power core engineering: design updates and trade-off studies a. rené...

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