Nuclear Fusion and Plasma Physics

Measurement of effective ion charge using visible bremsstrahlung on HL-2A tokamak

WEI Yan-ling, YU De-liang, LIU Liang

2014, 34(3): 193-199.

Asbtract ( )

PDF (1307KB) ( )

References | Related Articles | Metrics

The multichannel bremsstrahlung measurement system on HL-2A tokamak has been using to observe the intensity of visible (535.1nm) bremsstrahlung radiation. Combined the intensity with plasma electron density and electron temperature, the effective ion charge measurements can be obtained on HL-2A tokamak. The 1×10¹⁹m⁻³to 4×10¹⁹m⁻³ experimental results show that when the plasma electron density increases from 1×10 m to 4×10 m , the effective ion charge number changes from 5 down to around 2. The bremsstrahlung radiation signal intensity is proportional to the quadratic plasma density. When the electron density is higher than 3×10¹⁹m⁻³, the multichannel bremsstrahlung measurement system can collect sufficient signal through the plasma, which enables the measurement of effective ion charge radial profile.

Numerical simulation on thermal hydraulics characteristics of breeder pebble bed for China HCCB-TBM

WANG Wei-hua , CHENG De-sheng , FENG Kai-ming , DENG Hai-fei

2014, 34(3): 200-206.

Asbtract ( )

PDF (5185KB) ( )

References | Related Articles | Metrics

Based on the CFD software platform FLUENT, three-dimensional numerical simulation was carried out for thermal hydraulics characteristics of the breeder zone pebble bed for China helium cooled ceramic breeder-test blanket module (HCCB-TBM). According the actual operating conditions of ITER, such as the nuclear heat distributions in the breeder zone and structure wall, the inlet velocities and temperatures of purge gas helium and coolant helium, the flow field and heat transfer characteristics of the purge gas helium carrying the tritium flowing over the lithium silicate pebble bed were obtained, and the temperature distribution and pressure drop were presented as well. The calculation results show that the permutation mode of the lithium silicate spheres in the pebble bed have an influence on the flow field and the maximum temperature of the pebble-bed. The maximum temperature of the pebble-bed and the structure wall does not exceed the designed temperature under the ITER operating conditions. The results will be benefit for the design verification of the breeder zone thermal hydraulics scheme and improving the following experiments of the purge gas.

Effects of collisions on dust particle in a dusty plasma sheath

ZHAO Xiao-yun, ZHANG Bing-kai, ZHANG Kai-yin

2014, 34(3): 207-213.

Asbtract ( )

PDF (1012KB) ( )

References | Related Articles | Metrics

The fluid dynamics model was used to study the influence of the existence of the collisions on the dust particles in a dusty plasma sheath. The main collisions in this study consist of the ionization collision, the collision between electron and neutral particle, the collision between ion and neutral particle, the collision between electron and dust particle, the collision between ion and dust particle. Numerical calculation results are obtained by the fourth-order-Rung-Kutta method. It is shown that both the dust particles’ density and corresponding electricity quantity increase as the following collisions’ frequency enhances, such as ionization collision, the collision between electron and neutral particle, the collision between ion and neutral particle. The charge reduces due to the collisions concluding electron-dust particle and ion-dust particle. In addition, the effect produced by ions’ collision is much more obviously compared with electrons’ collision.

Influences of modulation instability on Compton scattering to linearly polarized laser pulse in relativistic plasma

GAO Hai-lin, PI Xiao-li, HAO Dong-shan

2014, 34(3): 214-218.

Asbtract ( )

PDF (421KB) ( )

References | Related Articles | Metrics

By using the model of multi-photon nonlinear Compton scattering, the nonlinear dispersion relation and Karpman’s model, the influences of the modulation instability on Compton scattering to the linear polarized light in relativistic plasma were studied, the revised equations on the nonlinear dispersion, the control and the growth rate of the modulation instability were given out, and these equations are simulated. The results show that under the same perturbation wave numbers, the even big rate of the modulation instability near the plasma surface are taken place by Compton scattering along with the decreasing of the numbers of the no gauge frequency than before Compton scattering, and the even marked growth rate of the modulation instability near the plasma surface are taken place near the plasma surface than other places. Because the plasma nonlinear is increased by the scattering, the self-focusing and self-turned fine silk are formed.

The design and analysis of HL-2M vacuum vessel

RAN Hong, CAO Zeng, CAI Li-jun, LI Yong, YUAN Ying-long

2014, 34(3): 219-223.

Asbtract ( )

PDF (7231KB) ( )

References | Related Articles | Metrics

HL-2M vacuum vessel is designed with a D-shaped, double thin-wall structure, which consists of inner shell, outer shell, ribs and ports. Torus inside and outside diameters are 2m and 5.22m, respectively. Torus height is 3.02m. The whole torus will be welded with 20 sectors. Inconel 625 、Inconel 718 and 316L are selected for the vessel material. Finite element analyses of vacuum vessel are conducted. The results show that vacuum vessel structure can meet the design requirements of the machine.

Structural design for the back plate of sub-module of CH HCCB TBM with 1×4 configuration

ZHAO Zhou, HU Gang, WANG Qi-jie, CAO Qi-xiang, ZHANG Guo-shu, FENG Kai-ming

2014, 34(3): 224-229.

Asbtract ( )

PDF (4543KB) ( )

References | Related Articles | Metrics

For China helium cooled ceramic breeder test banket module (CH HCCB TBM), a new structure with 1×4 configuration is proposed. Based on this new structure proposal, the detail structural design for the sub-module and its complicated back plate has been performed, also the preliminary pressure analysis for the back plate of sub-module has been finished.

Modified design and analysis for the first wall of CH HCCB TBM

WANG Qi-jie, CAO Qi-xiang, ZHAO Zhou, FENG Kai-ming

2014, 34(3): 230-234.

Asbtract ( )

PDF (5819KB) ( )

References | Related Articles | Metrics

Based on the CH HCCB TBM design, the detail of the new modified first wall (FW) was described, and a series related analysis was conducted to compare with former design. In the preliminary analysis, the modified FW design shows much more advantages in comparison with the former design. The working conditions of the analysis have been set to ITER design condition. The performances and the results obtained from thermo-hydraulics and stress analysis are presented.

Activation calculation and analysis for CFETR

SONG Huan, CHEN Zhi, LEI Jie-ying, JIANG Shuai

2014, 34(3): 235-239.

Asbtract ( )

PDF (700KB) ( )

References | Related Articles | Metrics

This paper considers the current China fusion engineering test reactor (CFETR) design, and simplifies it to a one-dimensional model. With the multi-particle transport code FLUKA, the neutron activation character of the tritium breeding blanket, shielding layer, vacuum vessel material and TFC of CFETR has been calculated to verify the radiation safety of the present design. The related results provide data reference for designing the components of CFETR and for further neutron activation analysis and calculation. The calculation results show that under the circumstances of one year operation with 200WM fusion power, the total radioactivity is 1.05×10 ¹⁹ Bq after shutdown and 1.03×10 ¹⁷ Bq after cooling for ten years. The primary residual nuclide is ⁵⁵ Fe after decaying for ten years. It shows that there isn’t seriously activation safety issue.

Tritium permeation of gas injection system for DEMO

WANG Jun, ZHANG Guo-shu, ZHANG Long

2014, 34(3): 240-246.

Asbtract ( )

PDF (2864KB) ( )

References | Related Articles | Metrics

In the present work, tritium permeation issue of gas injection system (GIS) in DEMO were focused. Based on the reactor core parameters of Chian Fusion Engineering Test Reactor (CFETR) and referring to accumulated experience of GIS design in ITER, preliminary pipes layout of DEMO GIS was performed. Steady-state tritium gas pressure drop calculation along the pipes and pump head request to the fuel storage and delivery system were made on the basis of the GIS’s structure layout. Tritium permeation under corresponding pump head was calculated at the same time. According to the calculation results, gravitational potential is the main determinant to pressure drop in pipe flow and the tritium permeation in GIS is of little amount to the whole tritium cycle in the case negative pressure. So this work offers related parameters to tritium self-sufficiency issues in DEMO, and also lays the foundation for further optimization of GIS’s structure layout.

Simulation of shaping large-size thin-walled elbow for ITER-PF feeder system

LIAN Long, WU Jie-feng, LI Bo, ZHOU Neng-tao

2014, 34(3): 247-251.

Asbtract ( )

PDF (6038KB) ( )

References | Related Articles | Metrics

The sheet metal forming software PAM-STAMP is used for stamping shaping simulation of elbow, then observe post-processing results. Respectively, the maximum and minimum thicknesses are 10.22mm and 8.63mm, the maximum principal stress and maximum Springbrook are 0.25GPa and 10.05mm. We can take it for comparison with the actual processing and analyze the reasons causing the errors. Finally it is verified that the results simulated by the software are accurate. It also provides a feasible processing solution for a large number of elbows of PF feeder system.

Design of constant current charging power supply for J-TEXT ohmic field capacitor banks

Lü Shu-dong1, 2, ZHANG Ming1, 2, YANG Cheng1, RAO Bo1, 2, YU Ke-xun1, 2

2014, 34(3): 252-258.

Asbtract ( )

PDF (1419KB) ( )

References | Related Articles | Metrics

The charging characteristic of the capacitor charging power supply was analyzed with practical series resonant topology. The method that setting two current taps and regulating PWM switching frequency was putted forward with close loop controlling algorithm to charge the multi-group capacitor banks with constant current. A capacitor charging power supply with the max output current 6.5A and the max output voltage 2000V is designed. Experimental results show that, this power supply can charge the four capacitor banks to any four different voltages in 1 minute with charging accuracy less than 1%, and meet the requirements of J-TEXT ohmic field power system.

Design of the AC power control system for dynamic resonant magnetic perturbation on the J-TEXT tokamak

ZHENG Mao-yue1, 2, RAO Bo1, 2, YI Bin1, 2, DING Yong-hua1, 2

2014, 34(3): 259-264.

Asbtract ( )

PDF (2974KB) ( )

References | Related Articles | Metrics

AC power control system designed for dynamic resonant magnetic perturbation (DRMP) on J-TEXT tokamak was introduced. It mainly focuses on analysis, design and optimization of an inverter control unit run in field programmable gate array (FPGA), based on all-digital phase-locked loop (ADPLL).Test results and performance of the system in the DRMP experiments are given. The results show that this power control system can fulfill the output frequency and phase control demand for the DRMP experiment and offer a reliable and stable operation.

Calibration of NS value of magnetic probe on EAST

SUN Jiu-yu, SHEN Biao, LIU Guang-jun, SUN You-wen, QIAN Jin-ping, LI Shi, XIAO Bing-jia, CHEN Da-long, SHI Tong-hui

2014, 34(3): 265-269.

Asbtract ( )

PDF (2039KB) ( )

References | Related Articles | Metrics

Based on the basic principle of measuring magnetic field by magnetic probe, a solenoid calibration system is constructed by a long solenoid, alternating current power, standard probe and data acquisition system in order to get the accurate magnetic field data. The NS value of magnetic probe on EAST is calibrated accurately by the solenoid calibration system and the data of the calibration is analysed. The obtained results are what we expected and provide the prerequisite for accurate magnetic field measurement in tokamak.

EAST transient electric field measurement system

ZHAO Hai-zeng , JI Zhen-shan , ZHU Chong-ming , WANG Yong

2014, 34(3): 270-274.

Asbtract ( )

PDF (1936KB) ( )

References | Related Articles | Metrics

The EAST transient electric field measurement system is designed for detecting the distribution and intensity of the transient electric field while the EAST is discharging, and can provide the basis for electromagnetic compatibility (EMC) design. It is composed of monopole electric-field probe, photoelectric isolation device, NI data acquisition equipment and software developed on LabVIEW to deal with the data. By testing, it can make synchronous data acquisition with sixteen analog channels, 20MHz sampling rate and up to 650MB⋅s^-1 throughput separately, which is able to meet the demand of acquiring, processing and storing the real-time data in the high-frequency analog signals multi-channel mode.

Insights into the deposition rate and microstructure of polysilicon films: effect of different hydrogen dilution ratio

SONG Sha-sha, ZUO Xiao, WEI Yu, CHEN Long-wei, SHU Xing-sheng

2014, 34(3): 275-281.

Asbtract ( )

PDF (2311KB) ( )

References | Related Articles | Metrics

Polycrystalline silicon thin film formation from inductively coupled plasma enhanced chemical vapor deposition system was studied. The dilution effect of H₂ on film deposition was discussed. The X-ray diffractometry, Raman spectra and scanning electron microscope measurement were carried out to analyze the influence of H₂ on the microstructures and the topography of polycrystalline silicon thin films. The optimum conditions for polycrystalline silicon thin films deposition were also discussed. The results indicated that polycrystalline silicon thin films with columnar structure crystals were fabricated on glass substrate. The deposition rate exhibited monotonic increase with Silane ratio R, a maximum deposition rate of 0.65nm⋅s^-1 was obtained. However, the crystal volume fraction of polycrystalline silicon thin films initially increased from 60.5% to 67.3%, and then slightly decreased with the increase of R. Therefore, the crystal has a maximum value of 67.3% at R=4.8%. The polycrystalline silicon thin films had a compact and well-arranged structure at this ratio. This structure can also increase carrier mobility and improve the efficiency of solar cells.

Electrode configuration and plasma reactor of spark discharge

DING Tian-ying, LIU Jing-lin , ZHU Ai-min

2014, 34(3): 282-288.

Asbtract ( )

PDF (1401KB) ( )

References | Related Articles | Metrics

Based upon demonstrating the discharge mechanism and plasma characteristic of spark discharge, electrode configuration and plasma reactor of spark discharge were discussed especially. A novel kHz AC spark discharge reactor with rotating electrode, developed in our group, was applied in methane pyrolysis to produce acetylene and reforming of methane with CO₂ to produce syngas. Its discharge stability, reactant conversion, product concentration and energy efficiency are higher obviously than those of other discharge reactors.

Table of Content