ZHENG Guo-yao, FENG Kai-ming, SHENG Guang-zhao 1) Southwestern Institute of Physics, Chengdu

1. 8th International Symposium on Fusion Nuclear Technology Sept. 30-Oct. 5, 2007, Heidelberg, Germany SWIP PS3-1014 Simulation of plasma parameters for HCSB-DEMO by 1.5D plasma transport code ZHENG Guo-yao, FENG Kai-ming, SHENG Guang-zhao 1) Southwestern Institute of Physics, Chengdu Abstract The main goals of the paper are aimed at simulating core plasma parameters of HCSB-DEMO (Helium-cooled Solid Breeder, HCSB) by 1.5D plasma transport code. The study content included: the operation scenarios; the temperature and density profiles of the ion and electron; fusion and radiation power; the distribution of current density and safety factor; sensitivity analyses for some of the input parameters and physical models parameters, finally, there is a primary estimate of the load of the divertor’s target. The fusion reactor parameters are as following: a major radius of 7.2m, aspect ratio of 3.4, elongation of 1.85, triangularity of 0.45, plasma current of 14.8MA, normalized beta of 4.4, maximum field of 13T, electron density of 1.5×1020/m3, average electron temperature of 14.5keV, fusion power of 2.55GW and neutron wall loading of 2.3 MW/m2 1. Introduction It was assumed that DEMO is a next step after ITER machine. Therefore, China DEMO studies are the important aspects of long-term national program to evaluate the technology, materials, economics, safety, environment and waste processing, for the possible magnetic fusion applications. The basic features of DEMO are: 1). Fusion power in a range of 2500~3000 MW with an average neutron wall loading of 2.0~3.0 MW/m2; 2). Long burning time with inductive operation or steady-state operation with reverse shear plasma modes; 3). NBI and RF system for current drive; 4). Detached or semi-detached divertor operation modes; 2. The simulation of plasma Under different plasma limited conditions, the fusion power, neutron wall loading, burn time and fusion gain in the fusion reactor with different sizes are calculated. The reactor which fit our requirements is selected for plasma operation contour analyses. The major radius is 7.2m, aspect ratio of 3.4, elongation of 1.85, triangularity of 0.45, plasma current of 14.8MA. Scaling of thermal energy confinement time used in calculated is ITERH-98P(y,2) . In 1.5D transport simulation, the current is flat-up at t=50s, 33 MW of NB heating is used at t=55s, 2MW of RF is used at beginning and increase to 22MW and 41 MW at t=100s and t=120s respectively. Time evolution of plasma and the profile of main plasma parameters are shown from Fig. 1 to Fig. 7 . Figure.2 Time evolution of average particle temperature Figure.1 Time evolution of electron density profile 2.1 Time evolution of plasma Fig. 1 shows time evolution of electron density profile. Fig.2 shows time evolution of average particle temperature. Fig.3 shows time evolution of fusion power and radiate power. 2.2 plasma profile at t=400s Fig. 4 shows electron and ion temperature profile at t=400s. Fig.5 shows electron and ion density profile at t=400s. Fig.6 shows total pressure and alpha pressure profile at t=400s. Fig.7 shows safety factor profile at t=400s. Figure.3 Time evolution of fusion power and radiate power Figure.4 Temperature profile at t=400s 3. The main plasma parameters The final parameters simulated by the 1.5D transport code for Inductive Operation Scenarios is showed at table 1, total Troyon factor is 4.4, average electron density is 1. 5 χ1020·m-3,average electron temperature is 15.4keV, average ion temperature is 15.8keV, bootstrap fraction is 80%, fusion power is 2550MW, total radiate power in the core is 211MW, about 36%, and 373MW across the separatrix. average neutron wall load is 2.3MW•m-2, Fusion gain is 35. Figure.6 Pressure profile at t=400s Figure.5 Density profile at t=400s Table.1 main plasma parameters Figure.8 Electron density profile with different pinch factor Figure.7 Safety factor profile at t=400s 4. Sensitivity analyses As there are some uncertain of some input parameters and the physical model, so after the simulation, it is necessary to do some sensitivity analyses about the uncertain parameters and models to see what influence will be about the fusion power. Fig.8 shows the electron density profile with different pinch factor. Figure.9 shows Fusion power relation with different pinch factor . Figure. 10 shows Fusion power relation with t*/tE . Figure.11 shows Fusion power relation with the fraction of Ar .Figure.12 shows Fusion power relation with different χi / χe Figure.9 Fusion power relation with different pinch factor Figure.10 Fusion power relation with t*/tE 5. Divertor heating load As mention above, about 373MW heating power will get across the separatrix . If do not radiate any power in the SOL, those power will damage the divertor target as heating load is over its load limited. If one third of heating power is radiated in the SOL, the inner divertor heating load is about 2.4MW/m2, the outer divertor heating load is 4.2 MW/m2. Figure.12 Fusion power relation with different χi / χe Figure.11 Fusion power relation with the fraction of Ar 6. Conclusion As mention above, the plasma parameters selected for HCSB-DEMO can satisfy its design requirement from the fusion power to the divertor heating load. In the sensitivity analyses, it can be found that there is some conservative estimate here. If some of the parameter (such as electron profile) is changed, that will produce more fusion power, so it is easy to make the fusion power over 3000MW.