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|Title:||The Stochastic Modelling of Fusion Product Transport and Thermalization With Nuclear Elastic Scattering|
|Author(s):||Deveaux, John Charles|
|Department / Program:||Nuclear Engineering|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Monte Carlo methods are developed to model fusion product(fp) transport and thermalization with both Rutherford scattering and nuclear elastic scattering(NES) in high-temperature(T(,i),T(,e) (GREATERTHEQ) 50 keV), advanced-fuel (e.g. Cat-D,D-('3)He) plasmas. A discrete-event model is used to superimpose NES collisions on a Rutherford scattering model that contains the Spitzer coefficients of drag, velocity diffusion(VD), and pitch-angle scattering(PAS). The recoil ions from NES are thermalized using a generation-by-generation approach in which the knock-ons generated during fp slowing down become the source term of the next generation of superthermal ions. Variance-reduction techniques including drag enhancement, the exponential transform, source biasing, and angular scattering biasing are applied to increase the comptational efficiency of the Monte Carlo simulations. Data for NES and Coulomb-nuclear interference(NI) cross sections is taken from the ENDL library at LLNL and bench-marked against NI data generated by R-Matrix methods at LANL.
The effects of NES on fp transport and thermalization are investigated for advanced-fuel, Field-Reversed Mirror(FRM) plasmas that have a significant Hamiltonian-canonical angular momentum(H-P(,(theta))) space loss cone which scales with the characteristic size(S(TBOND)R(,HV)/3(rho)(,i)) and applied vacuum magnetic field(B(,0)). For small, S = 5 FRM plasmas, fp heating is decreased by (TURN)10% due to enhanced loss-cone scattering from NES. With increasing S, the H-P(,(theta)) loss cone decreases thereby reducing fp losses during thermalization. For relatively large, S = 15 FRM plasmas, NES has a minimal impact on fp confinement but can transfer up to 30% more fp energy to the thermal ions than with Rutherford scattering alone. From a comprehensive parametric study, correlations were developed to estimate fp heating and ash deposition over a wide range of plasma parameters. These curves are inputted into a O-D burn code to determine the overall effects of NES on global plasma performance. For S = 15, D-('3)He plasmas the Q-value actually increases by (TURN)1-2% since enhanced ion heating dominates loss-cone scattering. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-16|
This item appears in the following Collection(s)
Dissertations and Theses - Nuclear, Plasma, and Radiological Engineering
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois