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Poloidal Distribution of ARIES-ACT Neutron Wall Loading. L. El-Guebaly, A. Jaber, D. Henderson Fusion Technology Institute University of Wisconsin-Madison http://fti.neep.wisc.edu/UWNeutronicsCenterOfExcellence Contributors: A. Robinson, T. Bohm, R. Slaybaugh, B. Smith, E. Marriott (UW),
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Poloidal Distribution of ARIES-ACT Neutron Wall Loading L. El-Guebaly, A. Jaber, D. Henderson Fusion Technology Institute University of Wisconsin-Madison http://fti.neep.wisc.edu/UWNeutronicsCenterOfExcellence Contributors: A. Robinson, T. Bohm, R. Slaybaugh, B. Smith, E. Marriott (UW), X. Wang (UCSD) ARIES Project Meeting UCSD San Diego, CA January 26 - 27, 2011
1/16th Sector (X. Wang) ARIES-ACT Geometry • 10/2010 or 1/2011 Strawman • Key parameters: R = 5.5 m a = 1.375 m Elongation = 2.2 Fusion power = 1907.4 MW • Surface areas: • Plasma = 475 m2 • Wall area: IB FW = 134 m2 OB FW = 285 m2 IB & OB FW= 419 m2 • Upper & lower divertors: IB plate = 26 x 2 m2 Dome = 34 x 2 m2 OB plate = 33 x 2 m2 Div total = 185 m2 FW + Div Surface area = 604 m2 5 m • Machine Ave NWL (MW/m2): (Pf x 0.8/area) ASC • @ plasma surface 3.2 2.2 • @ FW + divertor 2.6 ?
Neutronics Code and Model • 3-D Codes: • MCNP: for neutron and gamma transport • MCNPX: for neutron, gamma, and charged particle transport • DAG-MCNP: for neutron, gamma, and charged particle transport with added capability to import geometry directly from CAD. • 3-D NWL model: • Includes plasma boundary, IB & OB FW, and divertor IB&OB plates and dome. • FW and divertor segmented vertically and radially to improve accuracy • One million particle history • Statistical error < 1% • Neutron source sampled from plasma. MCNP 3-D Plot
Neutron Source Sampling • Options: • Uniform within plasma boundary – unrealistic, but used to check geometry • Three-nested regions (with peak at magnetic axis) - good approximation, but data unavailable • Actual distribution – exact method: • Source density distributed on R-Z grid • Data not available (to be provided by C. Kessel). MCNP 2-D Plot Uniform Source
Inboard Results Source Distribution Uniform Actual Machine Ave NWL (Pf x 0.8/area): @ plasma surface 3.2 3.2 @ FW + divertor 2.6 2.6 Peak IB NWL ~2.8 TBD (> 2.8) Ave IB NWL ~2.4 TBD IB FW Peak IB NWL
Outboard Results OB FW Source Distribution Uniform Actual Machine Ave NWL (Pf x 0.8/area): @ plasma surface 3.2 3.2 @ FW + divertor 2.6 2.6 Peak OB NWL ~3.6 TBD (> 3.6) Ave OB NWL ~3.5 TBD Peak OB NWL
Divertor Results Peak Div NWL Source Distribution Uniform Actual Machine Ave NWL (Pf x 0.8/area): @ plasma surface 3.2 3.2 @ FW + divertor 2.6 2.6 Peak div NWL ~3.5 TBD (< 3.5) Ave div NWL ~1.2 TBD
Summary of Results Source Distribution Uniform Actual ASC Machine Ave NWL (Pf x 0.8/area): @ plasma surface 3.2 3.2 2.2 ? @ FW + divertor 2.6 2.6 Peak IB NWL ~2.8 TBD Ave IB NWL ~2.4 TBD Peak OB NWL ~3.6 TBD Ave OB NWL ~3.5 TBD Peak div NWL ~3.5 TBD Ave div NWL ~1.2 TBD
Comments of CAD Drawing • IB & OB scrape off layers at midplane are 8.5 cm thick – inconsistent with ASC. • Straight IB FW? IB FW should conform to plasma to: • Reduce nuclear heating at magnet • Allow more space for DCLL He/LiPb manifolds • Capture neutrons before reaching divertor. • Check location of X-point relative to blanket and divertor: • IB/OB blanket extremities (marked with yellow dots) relative to X-point • Tighten divertor entrance as much as practically possible to reduce neutron leakage • Check flow of IB & OB charged particles to IB & OB divertor plates. ARIES-ACT OB FW IB FW
Future Work • UW will: • Repeat NWL calculations for actual neutron source distribution. • Perform radiation calculations with actual radiation source distribution. • Needed info: • Modified CAD drawing from X. Wang (fix SOL, IB/OB FW height, location of divertor plates relative to X-point) • Actual neutron source distribution on R-Z grid from C. Kessel • Actual radiation source distribution on R-Z grid from C. Kessel.