Analysis and Simulations of the ITER Hybrid Scenario C. Kessel, R. Budny, K. Indireshkumar Princeton Plasma Physics Laboratory, USA ITPA Topical Group on Steady State Operation and Enhanced Performance Centro di Cultura Scientifica - A. Volta Societa del Casino, Como Italy, May 2005
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Analysis and Simulations of the ITER Hybrid Scenario
Analysis and Simulations of the ITER Hybrid Scenario. C. Kessel, R. Budny, K. Indireshkumar Princeton Plasma Physics Laboratory, USA ITPA Topical Group on Steady State Operation and Enhanced Performance Centro di Cultura Scientifica - A. Volta Societa del Casino, Como Italy, May 2005. - PowerPoint PPT Presentation
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Analysis and Simulations of the ITER Hybrid Scenario
C. Kessel, R. Budny, K. IndireshkumarPrinceton Plasma Physics Laboratory, USA
ITPA Topical Group on Steady State Operation and Enhanced Performance
Centro di Cultura Scientifica - A. Volta
Societa del Casino, Como Italy, May 2005
Contents
• Groundrules for Hybrid Scenario– Goals– Plasma parameters and operating modes– Constraints
• 0D Systems analysis of Hybrid operating points– Brief description– Major parameters and effects of constraints– Large scan and operating space
• 1.5 D simulations of the Hybrid Scenario with TSC-TRANSP– Brief TSC-TRANSP description– TSC simulation results with GLF23 energy transport,
comments– TRANSP source modeling– Benchmarking of GLF23 energy transport DIII-D 104276
Hybrid Scenario in ITER
• Plasma parameter ranges E ≈ 1.0-1.5 E
98(y,2)
N < Nno wall (≈ 3)
– fNI ≈ 50%– IP ≈ 12 MA– n/nGr varied CD determined from TRANSP,
1.5 ≤ N ≤ 3.00.4 ≤ n/nGr ≤ 1.03.0 ≤ Q ≤ 12.00.0 ≤ fC ≤ 2.0%0.0 ≤ fAr ≤ 0.2%
Input parameters
Scanned parameters
ITER Hybrid Systems Analysis
Fusion power pulse length limitation significantly reduces accessible fluence values, and changes dependence on density
ITER Hybrid Systems AnalysisOperating space shows strong dependence on allowable conducted peak heat flux on divertor, which must be low enough to accommodate radiation flux and transients
ITER Hybrid Systems Analysis
Increasing the power radiated in the divertor can recover operating space at lower conducted peak heat flux
ITER Hybrid Systems Analysis
Large Operating Space Scan
1.05 ≤ n(0)/n ≤ 1.251.5 ≤ T(0)/T ≤ 2.511.0 ≤ IP (MA) ≤ 13.01.5 ≤ N ≤ 3.00.4 ≤ n/nGr ≤ 1.03.0 ≤ Q ≤ 12.01% ≤ fBe ≤ 3%0% ≤ fC ≤ 2%0% ≤ fAr ≤ 0.2%
Other input fixed at previous values
ITER Hybrid Systems Analysis
n n T T N q95 Ip HH fGr fBS fNI Zeff fBe fC fAr t/J
n = 0.05 --> n(0)/<n> = 1.04, n = 0.4 --> n(0)/<n> = 1.25T = 0.60 --> T(0)/<T> = 1.50, T = 2.0 --> T(0)<T> = 2.50
Results• Fusion power pulse length limitation is most significant
factor in determining Hybrid operating space– Lowering density does not continuously lead to better operating
points– Higher H98(y,2) allows access to higher fluence and lower n/nGr
– High fusion power is not necessary or desirable– Only low N ≈ 2 operating points are required
• Volt-seconds capability appears to be enough to offer few thousand second flattops
• Divertor heat load limits is next most significant factor for Hybrid operating space– Combination of conducted power, power radiated in divertor,
transient conducted power, and core radiated power
• First wall surface heat load limits do not appear to be limiting
• Available operating space shows that existing ITER design can provide reasonable fluence levels within a discharge, HOWEVER time between discharges is constrained– Appears that cryoplant limitation sets tflat/(tflat+tdwell) ≈ 25%
TSC TRANSP
Discharge simulation with assumed source profiles and evolving boundary
Plasma geometryT, n profilesq profile
Interpretive rerun of discharge simulation with source models, fast ions, neutrals (TSC as expt.)
Accurate source profiles fed back to TSC Analysis with interfaces
to TRANSP
Analysis with interfaces to TSC
Flow Diagram of TSC-TRANSP 1.5D Analysis Combining Strengths of the Two
Codes
TSC and TRANSP, a Few* Attributes
• TRANSP
– Interpretive**
– Fixed boundary Eq. Solvers
– Monte Carlo NB and heating
– SPRUCE/TORIC/CURRAY for ICRF
– TORAY for EC
– LSC for LH
– Fluxes and transport from local conservation; particles, energy, momentum
– Fast ions
– Neutrals
• TSC– Predictive– Free-boundary/structures/PF
coils/feedback control systems
– T, n, j transport with model or data coefficients (, , D, v)
– LSC for LH (benchmark with other LH codes)
– Assumed P and j deposition for NB, EC, and ICRF: typically use off-line analysis to derive these
*In addition, both codes have models for bootstrap current, radiation, sawteeth, ripple loss, pellet fueling, impurities, etc. ** TRANSP has predictive capability
TRANSP NBCD Results for Various Conditions in the ITER Hybrid Simulations, t