Inertial Electrostatic Confinement Fusion Reactor Liquid Cooled Ion Accelerating Grid Design

Inertial Electrostatic Confinement Fusion ReactorLiquid Cooled Ion Accelerating Grid DesignA. Seltzman, Georgia Institute of TechnologyAbstract:Reactor Design:IEC Fusion Overview:Results:Future Work: Traditional inertial electrostatic confinement (IEC) fusion reactor designs utilize an ion accelerating grid fabricated out of a refractory metal capable of operating at high temperatures to radiate off heat imparted by ion-grid collisions. Unfortunately, the high gird temperature allows for a substantial thermionic electron emission current, requiring a high power draw and significantly reducing reactor efficiency. Further, electrons emitted from the grid are accelerated into the reactor shell where they generate a significant amount of bremsstrahlung x-rays requiring additional shielding and increasing system size and weight. Presented is a novel modification to the traditional implementation of IEC fusion reactor, designed to improve operating efficiency by reducing electron emission from the grid. A liquid cooled grid design is utilized to reduce thermionic electron emission, allowing for higher plasma densities, and greater input power while improving system efficiency and reducing x-ray output. The resulting low grid temperatures substantially reduce thermionic electron emission and greatly improve reactor efficiency by reducing current draw from the central grid. The reduction of thermionic electron emission will eliminate the majority of bremsstrahlung x-ray generation thereby reducing shielding requirements. By measuring the heat deposited into the coolant, the grid cooling system may also be used as a diagnostic tool to study the physics involved in IEC reactors. In this manner, grid transparency may be directly measured as a function of ion bombardment heating. By modifying the confinement scheme of the reactor and subsequently evaluating the energy flux to the grid through ion collisions, greater energy and particle confinement times may be obtained.Deuterium Plasma: 13kV, 5mA, 16mTorrIEC Reactor Core DesignMark 3 IEC Reactor CoreCooled Ion Accelerating Grid DesignGrid Cooling SystemIon Accelerating GridECRF Ion Injector DesignECRF Ion Injector AssemblyReactor DesignModular, portable designHigh efficiency neutron productionCooled grid design reduces unwanted x-ray emissionOn demand deuterium generation from heavy water reserveOnboard ECRF drive systemLabview Control, USB interfaceNeutron DetectorVacuum EnvelopeFluorinert MicropumpPrimary Cooling RadiatorVacuum HubECRF Drive AmplifierAccelerating Grid SystemECRF InjectorGrid Cooling SystemPrimary cooling loop radiator removes heat from waterWater cooled Fluorinert chiller assemblyThermoelectric chiller assembly allows compact, high performance cooling of gridFluorinert grid cooling loopCooled Grid AssemblyLow operating temperature to reduce thermionic electron emission current.High voltage bias (-50kV)Three ring grid fabricated from 1/16 OD stainless steel tubeNon-conductive Fluorinert coolantHigh flow rate (1ml/s at 80 PSI)Ceramic cooling system isolationVacuum compatible alumina ceramic feedthroughsECRF Injector SystemRF drive system operational, Injector system in testingRF ionization of X-mode electron cyclotron resonance at 880MHz Provides low pressure stabilityIncreases plasma density and energy while reducing ion-grid collisionsFluorinert ChillerResults and design documentation posted at:www.rtftechnologies.orgIon TrajectoryProblem to be Solved:Grid heating due to ion bombardment causes thermionic electron emission, thereby increasing reactor power draw and generating unwanted x-ray radiation.Ion Bombardment HeatingReactor OperationalDeuterium fusion detected via neutron generationCooled grid remains below 45C at 155W drive power.Grid serves as diagnostic tool to determine fraction of drive power dissipated into grid heatingDiagnostic Use of Grid CoolingBy measuring coolant feed and return temperature, ion bombardment heating power and grid temperature may be directly measuredBy comparing grid heating to reactor drive power, a direct measurement of grid transparency may be obtainedThe resulting trends in heating vs. input power and pressure may be used to determine stable operating regions for non-cooled grid reactors

Grid Cooling DataAs plasma impedance increases, grid heating power fraction decreasesAs plasma density decreases, slope of Grid Heating vs. Drive Power decreasesAs drive power increases, plasma impedance decreases

Solution:A liquid cooled ion accelerating grid remains cool at high operating power, allowing increased plasma density and higher operating efficiency by eliminating thermionic electron emission.Thermionic Electron EmissionDeuterium FusionCentral grid negatively biasedIons oscillate in electrostatic fieldIons collide at focal point and fuseFusion generated high energy neutrons and protonsGrid HeatingA fraction of the accelerated ions collide with the grid heating it.A radiatively cooled grid will operate at high temperaturesAt high temperatures the grid emits a large thermionic electron current, generating a substantial power drawEmitted electrons are accelerated into the reactor shell where they generate bremsstrahlung x-rays.

Chart1

4.578753.357757.93654.4261251.6788752.74725

7.631258.5478.852253.6632.136752.899875

10.6837512.97312511.14162513.2783752.747254.426125

10.53112519.38337515.10987515.567753.510375

3.6632.1367521.6727518.7728754.731375

5.6471257.936525.030523.504256.41025

17.09411.599510.836375

3.81562517.5518752.13675

4.7313753.663

5.9523755.036625

9.0048757.326

12.362625

15.873

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr

P: Drive Power(W), Ion source on

H: Grid Heating (W)

y(25mTorr) = 0.0721x1.2553R2 = 0.9822

y(20mTorr) = 0.0816x1.1471R2 = 0.9985

y(16mTorr) = 0.1139x1.0468R2 = 0.9984

y(14.5mTorr) = 0.0937x1.0712R2 = 0.9926

Sheet1

Coolant:Fluorinert FC-40

Pressure:60PSI

Flow:0.75cc/sec

Density:1850kg/m^3

Specific Heat1100J/(kg*C)

Power Disipation:1.52625W/C

Data Points:

3/27/08 data

Pres(Torr)Grid(kV)Grid(mA)Power(W)TinToutTdeltaHeating(W)H/PAVG H/PV(kV)/I(mA)

25mTorr Data =>0.0243.95.220.2823.8262.23.357750.16556952660.75

0.0253.9103923.829.45.68.5470.21915384620.39

0.0254.11561.523.932.48.512.9731250.2109451220.2733333333

0.0264.5209024.537.212.719.3833750.21537083330.225

0.0244.53.616.224.826.21.42.136750.13189814811.25

0.0254.6104624.930.15.27.93650.17253260870.18591168080.46

16mTorr Data =>0.016843225.328.22.94.4261250.13831640622

25mR/h at VP0.0168.23.427.8825.427.82.43.6630.1313845052.4117647059

p (mTorr)exp

3/31/08 data251.2553

Pres(Torr)Grid(kV)Grid(mA)Power(W)TinToutTdeltaHeating(W)H/PAVG H/PV(kV)/I(mA)201.1471

31mtorr31.31.581015.823.226.234.578750.28979430380.158161.0468

31.31.915.529.4523.328.357.631250.25912563670.1225806452141.0712

31.32.1518.339.34523.430.4710.683750.27154022110.1174863388130.962

31.32.217.738.9423.530.46.910.5311250.27044491530.1242937853

31.32.56.215.523.726.12.43.6630.23632258060.4032258065

31.32.681026.823.827.53.75.6471250.21071361940.268

31.32.96257423.935.111.217.0940.2310.1184

31.32.85.214.5624.226.72.53.8156250.26206215660.5384615385

31.337.823.424.327.43.14.7313750.20219551280.3846153846

31.33.089.930.49224.328.23.95.9523750.1952110390.3111111111

31.33.314.547.8524.330.25.99.0048750.18818965520.2275862069

31.33.351963.6524.432.58.112.3626250.19422820110.1763157895

31.33.4721.474.25824.434.810.415.8730.2137547470.23266019910.1621495327

20mTorr20.85.79.755.2924.729.95.27.93650.14354313620.587628866

20.85.8105824.730.55.88.852250.1526250.58

20.85.8512.472.5424.832.17.311.1416250.15359284530.4717741935

20.85.981695.6824.834.79.915.1098750.15792093440.37375

20.86.121.4130.5424.83914.221.672750.16602382410.285046729

20.86.2223.5146.172541.416.425.03050.1712423890.15749135480.2646808511

pAVG H/P

16mTorr168.411.294.0825.634.38.713.2783750.14113919010.7531.30.2326601991

168.4113.1110.17125.735.910.215.567750.14130533440.6419847328250.1859116808

168.3515.6130.2625.73812.318.7728750.14411849380.5352564103200.1574913548

17.68.1519.2156.4825.841.215.423.504250.15020609660.4244791667160.1417915626

168.89.886.2426.233.87.611.59950.1345025510.8979591837140.1202911405

8.814.3125.8426.137.611.517.5518750.13947770980.14179156260.6153846154130.1018718839

14mTorr14.58.41.714.2826.327.41.11.6788750.11756827734.9411764706

14.58.6217.226.227.61.42.136750.12422965124.3

14.58.72.723.4926.2281.82.747250.1169540233.2222222222

14.58.783.429.85226.228.52.33.5103750.11759262362.5823529412

14.58.94.540.0526.229.33.14.7313750.11813670411.9777777778

14.595.650.426.130.34.26.410250.12718751.6071428571

14.599.383.726.233.37.110.8363750.12946684590.9677419355

14.58.652.420.7626.527.91.42.136750.10292630063.6041666667

14.58.83.530.826.428.82.43.6630.11892857142.5142857143

14.58.94.640.9426.429.73.35.0366250.12302454811.9347826087

14.596.457.626.531.34.87.3260.12718750.12029114051.40625

13mTorr1310.82.52726.528.31.82.747250.101754.32

10.82.628.0826.428.31.92.8998750.10327190174.1538461538

500mR/h at VP1144426.429.32.94.4261250.100593750.10187188392.75

Sheet1

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr


H: Grid Heating (W)

y(25mTorr) = 0.0721x1.2553R2 = 0.9822

y(20mTorr) = 0.0816x1.1471R2 = 0.9985

y(16mTorr) = 0.1139x1.0468R2 = 0.9984

y(14.5mTorr) = 0.0937x1.0712R2 = 0.9926

Sheet2

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr

H: Drive Current(mA), Ion source on

H: Grid Heating (W)

Sheet3

Pressure (mTorr)

P-H Curve Exponent

Pressure (mTorr)

H/P: Grid Heating (W) / Drive Power(W)

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr


Z(MOhm): Drive Voltage(kV) / Drive Current(mA)

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr



Chart5

0.28979430380.16556952660.14354313620.13831640620.11756827730.10175

0.25912563670.21915384620.1526250.1313845050.12422965120.1032719017

0.27154022110.2109451220.15359284530.14113919010.1169540230.10059375

0.27044491530.21537083330.15792093440.14130533440.1175926236

0.23632258060.13189814810.16602382410.14411849380.1181367041

0.21071361940.17253260870.1712423890.15020609660.1271875

0.2310.1345025510.1294668459

0.26206215660.13947770980.1029263006

0.20219551280.1189285714

0.1952110390.1230245481

0.18818965520.1271875

0.1942282011

0.213754747

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr



Sheet1


Pressure:60PSI

Flow:0.75cc/sec

Density:1850kg/m^3


Power Disipation:1.52625W/C

Data Points:

3/27/08 data


25mTorr Data =>0.0243.95.220.2823.8262.23.357750.16556952660.75

0.0253.9103923.829.45.68.5470.21915384620.39

0.0254.11561.523.932.48.512.9731250.2109451220.2733333333

0.0264.5209024.537.212.719.3833750.21537083330.225

0.0244.53.616.224.826.21.42.136750.13189814811.25

0.0254.6104624.930.15.27.93650.17253260870.18591168080.46

16mTorr Data =>0.016843225.328.22.94.4261250.13831640622

25mR/h at VP0.0168.23.427.8825.427.82.43.6630.1313845052.4117647059

p (mTorr)exp

3/31/08 data251.2553


31mtorr31.31.581015.823.226.234.578750.28979430380.158161.0468

31.31.915.529.4523.328.357.631250.25912563670.1225806452141.0712

31.32.1518.339.34523.430.4710.683750.27154022110.1174863388130.962

31.32.217.738.9423.530.46.910.5311250.27044491530.1242937853

31.32.56.215.523.726.12.43.6630.23632258060.4032258065

31.32.681026.823.827.53.75.6471250.21071361940.268

31.32.96257423.935.111.217.0940.2310.1184

31.32.85.214.5624.226.72.53.8156250.26206215660.5384615385

31.337.823.424.327.43.14.7313750.20219551280.3846153846

31.33.089.930.49224.328.23.95.9523750.1952110390.3111111111

31.33.314.547.8524.330.25.99.0048750.18818965520.2275862069

31.33.351963.6524.432.58.112.3626250.19422820110.1763157895

31.33.4721.474.25824.434.810.415.8730.2137547470.23266019910.1621495327

20mTorr20.85.79.755.2924.729.95.27.93650.14354313620.587628866

20.85.8105824.730.55.88.852250.1526250.58

20.85.8512.472.5424.832.17.311.1416250.15359284530.4717741935

20.85.981695.6824.834.79.915.1098750.15792093440.37375

20.86.121.4130.5424.83914.221.672750.16602382410.285046729

20.86.2223.5146.172541.416.425.03050.1712423890.15749135480.2646808511

pAVG H/P

16mTorr168.411.294.0825.634.38.713.2783750.14113919010.7531.30.2326601991

168.4113.1110.17125.735.910.215.567750.14130533440.6419847328250.1859116808

168.3515.6130.2625.73812.318.7728750.14411849380.5352564103200.1574913548

17.68.1519.2156.4825.841.215.423.504250.15020609660.4244791667160.1417915626

168.89.886.2426.233.87.611.59950.1345025510.8979591837140.1202911405

8.814.3125.8426.137.611.517.5518750.13947770980.14179156260.6153846154130.1018718839

14mTorr14.58.41.714.2826.327.41.11.6788750.11756827734.9411764706

14.58.6217.226.227.61.42.136750.12422965124.3

14.58.72.723.4926.2281.82.747250.1169540233.2222222222

14.58.783.429.85226.228.52.33.5103750.11759262362.5823529412

14.58.94.540.0526.229.33.14.7313750.11813670411.9777777778

14.595.650.426.130.34.26.410250.12718751.6071428571

14.599.383.726.233.37.110.8363750.12946684590.9677419355

14.58.652.420.7626.527.91.42.136750.10292630063.6041666667

14.58.83.530.826.428.82.43.6630.11892857142.5142857143

14.58.94.640.9426.429.73.35.0366250.12302454811.9347826087

14.596.457.626.531.34.87.3260.12718750.12029114051.40625

13mTorr1310.82.52726.528.31.82.747250.101754.32

10.82.628.0826.428.31.92.8998750.10327190174.1538461538

500mR/h at VP1144426.429.32.94.4261250.100593750.10187188392.75

Sheet1

000000

000000

000000

00000

00000

00000

000

000

00

00

00

0

0

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr


H: Grid Heating (W)

y(25mTorr) = 0.0721x1.2553R2 = 0.9822

y(20mTorr) = 0.0816x1.1471R2 = 0.9985

y(16mTorr) = 0.1139x1.0468R2 = 0.9984

y(14.5mTorr) = 0.0937x1.0712R2 = 0.9926

Sheet2

000000

000000

000000

00000

00000

00000

000

000

00

00

00

0

0

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr


H: Grid Heating (W)

Sheet3

0

0

0

0

0

Pressure (mTorr)

Power-Heating Curve Exponent

00

00

00

00

00

0

Average H/P

H/P Exponent

Pressure (mTorr)



000000

000000

000000

00000

00000

00000

000

000

00

00

00

0

0

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr



000000

000000

000000

00000

00000

00000

000

000

00

00

00

0

0

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr



Chart2

0.1580.750.58762886624.94117647064.32

0.12258064520.390.582.41176470594.34.1538461538

0.11748633880.27333333330.47177419350.753.22222222222.75

0.12429378530.2250.373750.64198473282.5823529412

0.40322580651.250.2850467290.53525641031.9777777778

0.2680.460.26468085110.42447916671.6071428571

0.11840.89795918370.9677419355

0.53846153850.61538461543.6041666667

0.38461538462.5142857143

0.31111111111.9347826087

0.22758620691.40625

0.1763157895

0.1621495327

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr

P: Drive Power(W)


Sheet1


Pressure:60PSI

Flow:0.75cc/sec

Density:1850kg/m^3


Power Dissipation:1.52625W/C

Data Points:

3/27/08 data


25mTorr Data =>0.0243.95.220.2823.8262.23.357750.16556952660.75

0.0253.9103923.829.45.68.5470.21915384620.39

0.0254.11561.523.932.48.512.9731250.2109451220.2733333333

0.0264.5209024.537.212.719.3833750.21537083330.225

0.0244.53.616.224.826.21.42.136750.13189814811.25

0.0254.6104624.930.15.27.93650.17253260870.18591168080.46

16mTorr Data =>0.016843225.328.22.94.4261250.13831640622

25mR/h at VP0.0168.23.427.8825.427.82.43.6630.1313845052.4117647059

p (mTorr)exp

3/31/08 data251.2553


31mtorr31.31.581015.823.226.234.578750.28979430380.158161.0468

31.31.915.529.4523.328.357.631250.25912563670.1225806452141.0712

31.32.1518.339.34523.430.4710.683750.27154022110.1174863388130.962

31.32.217.738.9423.530.46.910.5311250.27044491530.1242937853

31.32.56.215.523.726.12.43.6630.23632258060.4032258065

31.32.681026.823.827.53.75.6471250.21071361940.268

31.32.96257423.935.111.217.0940.2310.1184

31.32.85.214.5624.226.72.53.8156250.26206215660.5384615385

31.337.823.424.327.43.14.7313750.20219551280.3846153846

31.33.089.930.49224.328.23.95.9523750.1952110390.3111111111

31.33.314.547.8524.330.25.99.0048750.18818965520.2275862069

31.33.351963.6524.432.58.112.3626250.19422820110.1763157895

31.33.4721.474.25824.434.810.415.8730.2137547470.23266019910.1621495327

20mTorr20.85.79.755.2924.729.95.27.93650.14354313620.587628866

20.85.8105824.730.55.88.852250.1526250.58

20.85.8512.472.5424.832.17.311.1416250.15359284530.4717741935

20.85.981695.6824.834.79.915.1098750.15792093440.37375

20.86.121.4130.5424.83914.221.672750.16602382410.285046729

20.86.2223.5146.172541.416.425.03050.1712423890.15749135480.2646808511

pAVG H/P

16mTorr168.411.294.0825.634.38.713.2783750.14113919010.7531.30.2326601991

168.4113.1110.17125.735.910.215.567750.14130533440.6419847328250.1859116808

168.3515.6130.2625.73812.318.7728750.14411849380.5352564103200.1574913548

17.68.1519.2156.4825.841.215.423.504250.15020609660.4244791667160.1417915626

168.89.886.2426.233.87.611.59950.1345025510.8979591837140.1202911405

8.814.3125.8426.137.611.517.5518750.13947770980.14179156260.6153846154130.1018718839

14mTorr14.58.41.714.2826.327.41.11.6788750.11756827734.9411764706

14.58.6217.226.227.61.42.136750.12422965124.3

14.58.72.723.4926.2281.82.747250.1169540233.2222222222

14.58.783.429.85226.228.52.33.5103750.11759262362.5823529412

14.58.94.540.0526.229.33.14.7313750.11813670411.9777777778

14.595.650.426.130.34.26.410250.12718751.6071428571

14.599.383.726.233.37.110.8363750.12946684590.9677419355

14.58.652.420.7626.527.91.42.136750.10292630063.6041666667

14.58.83.530.826.428.82.43.6630.11892857142.5142857143

14.58.94.640.9426.429.73.35.0366250.12302454811.9347826087

14.596.457.626.531.34.87.3260.12718750.12029114051.40625

13mTorr1310.82.52726.528.31.82.747250.101754.32

10.82.628.0826.428.31.92.8998750.10327190174.1538461538

500mR/h at VP1144426.429.32.94.4261250.100593750.10187188392.75

Sheet1

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr


H: Grid Heating (W)

y(25mTorr) = 0.0721x1.2553R2 = 0.9822

y(20mTorr) = 0.0816x1.1471R2 = 0.9985

y(16mTorr) = 0.1139x1.0468R2 = 0.9984

y(14.5mTorr) = 0.0937x1.0712R2 = 0.9926

Sheet2

31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr


H: Grid Heating (W)

Sheet3

Pressure (mTorr)


Average H/P

H/P Exponent

Pressure (mTorr)



31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr



31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr

Drive Voltage(kV)


31mTorr

25mTorr

20mTorr

16mTorr

14.5mTorr

13mTorr

P: Drive Power(W)


Inertial Electrostatic Confinement Fusion Reactor Liquid Cooled Ion Accelerating Grid Design

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