A Materials Evaluation Neutron Source Based on the Gas Dynamic Trap

(DTNS) One Element in an Urgently Needed

Comprehensive Fusion Materials Program

Based on a Mirror Status Workshop Berkeley, CA. Sept. 8-9, 2008

25 Participants - 6 Labs. and 5 Universities - Japan & Russia

T. C. Simonen, ChairRenews Workshop March 2-6, 2009

The Simple Axisymmetric Mirror A Physics & Engineering Game Changer

• Simple magnet geometry stabilized by plasma exhaust– Physics established: Novosibirsk GDT Device – 60% beta, Te, classical– Extrapolates to a Dynamic Trap D-T Neutron Source (DTNS)– ~ 2 MW/m2 Neutron Flux, ~2 m2 Area, ~100 Liter Volume– Simple Geometry, Ease of Construction & Maintenance– Addresses Greenwald Gaps 10 & 13 and Initiative 7 Neutron Source

3

GDT at Novosibirsk, Russia12 m Long with Large End Tanks to Decouple Te

One Version of DTNS Showing Magnets, Shielding ,Neutral Beams, and Material Samples

(Bobouch, Fusion Science & Tech. 41 (2002) p44)

Neutron Flux Scales With Te to 4 MW/m2(for various NBI energies)

DTNS Could Produce ITER-Like Neutron Energy Spectra

(Fischer, A.Moslang, A.Ivanov, FE&D 48 (2000) p.307)

DTNS Would Operate at Higher Magnetic Field, Neutral Beam Energy, and Power than GDT

GDT Achieved DTNS Design

Beta (%) 60 60

Beam Power (MW) 4 30

Beam Energy (kV) 20 80

Ion Energy (keV) 10 40

Electron Temp (eV) 230 750

Density (10e20 m-3) 1 4

Energy Confinement Time (ms)

2 2

Pulse Duration 5 ms cw

DTNS Has Two Test Zones

• Neutron Flux concentrates in regions of beam ion Turning Points– One Zone could test many material samples– One Zone could test Sub-components

Small Material Sample Test Assembly(Holds ~8,000 Temp. Controlled Specimens)

ref: U. Fisher, A. Moslang, A.A. Ivanov, FE&D 48 (2000) p307

Monte Carlo Calculation Indicates Uniform Radial-Axial Neutron Flux

(r-uniformity < 5%/cm, z-uniformity < 0.1%/cm)

Materials Testing Neutron Sources RTNS

D-T

82-87

IFMIF

D+Li

DTNS

D-T

FDF/CTF

D-T

Neutron Power

(MW)

20 W ? 2+ 100-300

30-160

Flux (MW/m2) 0.2 1.5 2+ 2 - 3

1 - 3

Area (m2) .0001 0.01 2 70

15

Tritium (kg/FPY) ~0 0 0.15 ~2 to 20 without breeding

Cost ($M) FY08 1000 325-650 ?

1500

Summary– The DTNS is an Attractive D-T Neutron Source That Closes Gaps 10 & 13

and Initiative 7 for Materials Testing

• ITER-Like Neutron Energy Spectrum

• Produces 1-4 MW/m2

• Provides ~2 m2 Test Area

• Provides ~100 Liter Test Volume

• Uniformity < 5%/cm

Suggested Next Steps

• Collaboration with Novosibirsk GDT– Diagnostics (Thomson Scattering, …)– GDT-Upgrade (4 MW to 10 MW)

• Theory-Modeling to– Extrapolate to DTNS (Te, MHD, DCLC, TPM )– Seek More Efficient Design (end cells)– Deploy US Theory Capabilities (e.g. UTexas, LLNL,

LANL, Lehigh, etc, etc)• Initiate DTNS Design• Construct DTNS (could be phased)

Additional Benefits of DTNS Activity

• DTNS Physics Has Much in Common with Other Confinement Systems

• Tests Existing Modeling Capability in Very Simple Geometry

• More Efficient DTNS (end cells) Leads to a Fusion-Fission Hybrid

• Benefits Outside Magnetic Fusion

• Fosters International Collaboration

References

• Gas dynamic trap as high power 14 MeV neutron source, P.A Bagryansky , et. al. Fusion Engineering and Design 70 (2004), p13-33

• Assessment of the gas dynamic trap mirror facility as intense neutron source for fusion material test irradiations, U. Fischer, A. Moslang, A.A. Ivanov, Fusion Engineering and Design, 48 (2000) p307-325