Southwestern Institute Of Physics Research Articles

3D Numerical Study of MHD Flow in a Rectangular Duct with a Flow Channel Insert

This study continues our ongoing investigation of magnetohydrodynamic (MHD) flows in poloidal ducts of the Dual-Coolant Lead-Lithium (DCLL) blanket with an insulating flow channel insert (FCI). We report our first 3D modeling results for an approximately ideally non-conducting FCI. The FCI and duct geometry match those of an experiment performed recently in Southwestern Institute of Physics (SWIP), China. The experimental FCI is made of epoxy and has a pressure equalization slot (PES) in one wall, which is perpendicular to the applied magnetic field. Previous 2D modeling efforts based on the fully developed flow model have demonstrated a significant difference with the experimental results in the MHD pressure drop, indicating 3D effects may be significant. The new 3D results, obtained with an unstructured, parallel MHD solver HIMAG, are in fair agreement with the experimental data. These results confirm a substantial reduction in MHD pressure drop by the FCI, but not as significant as would be expected under fully developed flow conditions.

Acceleration and Redeposition of a Dust Particle in SOL/Divertor Plasma of HL‐2A Tokamak

AbstractAcceleration of a iron dust particle is studied in the SOL (Scrape‐Off Layer)/divertor plasma of the HL‐2A tokamak in Southwestern Institute of Physics, China, with a single‐null configuration. In this study the simplest model of the dust dynamics is applied: spherical shape of a dust, ion drag force due to Coulomb scattering and drag force due to the plasma ion absorption as dominant forces, and spontaneous charging of a dust particle to the equilibrium charge. In the outer region near the plasma‐facing wall the parallel plasma flow along the magnetic field pushes the dust particle to the divertor plates. It is clarified that the dust particle with a radius of 1mm from the top of the SOL/divertor region is accelerated up to around 100 m/s in a few hundreds milliseconds to the divertor plates. In our model even the small dust particle with 1nm size can overcome the sheath potential and redeposite on the divertor plate (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Impact of injecting positions on penetration and deposition of supersonic molecular beam on Tokamak

Fuelling and particle control are important topics for ITER physics. Because of the low efficiency of gas puffing and the high cost of pellet injection, other methods were explored in the last decades. A new method for plasma gas fueling, the pulsed supersonic molecular beam injection (SMBI) was successfully developed at Southwestern Institute of Physics in China and applied on HL-1M and HL-2A devices in recent years. SMBI possesses a great advantage over conventional gas puffing, mainly due to the higher instantaneous fueling intensity and speed, smaller spread of velocity and angular distribution of the particles than the latter. In this paper, we report the experiment results of the SMB injected from LFS and HFS in HL-2A device, the effect of  Δ B on SMB penetration is considered. During SMB injection in Tokamak, there is a rapid movement of the ablation beam substance towards the outward major radius R direction. The favorable injection from the high field side in order to promote deeper fuel penetration can be obtained. The motion has been attributed to a vertical curvature and  Δ B drift current induced inside the ionized ablated SMB particles by the 1/R toroidal field variation. The uncompensated vertical drift current inside the weakly diamagnetic ablation particles will cause charge separation at the plasma edge. The resulting electrostatic field induces the  E×B  drift to the large R side of the torus.

Helium Retention and Desorption Behaviour of Reduced Activation Ferritic/Martenstic Steel

The reduced activation ferritic/martenstic steel CLF-1 prepared by the Southwestern Institute of Physics in China was irradiated by helium ions with an energy of 5 keV at room temperature using an electron cyclotron resonance (ECR) ion irradiation apparatus. After the irradiation, the helium retention and desorption were investigated using a technique of thermal desorption spectroscopy (TDS). The experiment was conducted with both the normal and welded samples. Blisters were observed after the helium ion irradiation, and the surface density of blisters in the welded samples was lower than that in the non-welded samples. Three desorption peaks were observed in both the non-welded and welded samples. These desorption peaks corresponded to those of blister ruptures and the helium release from the inner bubbles and the defects. The amount of helium retained in the welded samples was approximately the same as that in the non-welded samples, which was much less than other reduced activation materials, such as vanadium alloy and SiC/SiC composites.

MHD stabilities of liquid metal jet flows with gradient magnetic field

Liquid metal free surface flows (films, jets and droplets) are considered as prospective coolants in diverter/limiter system and first wall in fusion reactor, but the knowledge of liquid metal free surface, particularly jet flows, is very limited. In this article, the stability of a jet flow under a gradient magnetic field is investigated, and its MHD effects are the top concern. Firstly, a simplified model is developed to analyze the MHD effects of the jet flow and to explain the reason why it can keep stable, and the examination of the induced electric potential and currents of the jet flow is also included. Secondly, numerical simulation based on the approach of solving the electric potential equation was proceeded to support the theoretical analysis. Finally, experiments with different value of B 0 (maximum value of the magnetic field) and v 0 (average fluid velocity at the nozzle exit), and different kind of nozzle were performed on the Liquid Metal Experimental Loop (LMEL) in Southwestern Institute of Physics (SWIP), and there's a good agreement with experimental data and theoretical results. Qualitatively, a jet flow under a gradient magnetic field can keep its shape stable due to electromagnetic (EM) force in its direction and the compressed EM force in its cross-section, meanwhile, the reduction in velocity leads to a shorter range distance and a lager radius of cross-section of the jet flow. These effects are closely related to the parameters of the radius of the nozzle, the values of B 0 and v 0 .

Commissioning and preliminary operation of HL-2A tokamak

HL-2A is a divertor tokamak located at new site of Southwestern Institute of Physics (SWIP), Chengdu, China. It can be operated in double-null and single-null divertor with closed configurations. The effects of the divertor on impurity behaviors, MHD instabilities, transport, wall conditioning and divertor physics are key issues to be studied during the first step operation on HL-2A. Preliminary experiments with limiter and single null divertor configurations were carried out in 2003. Main parameters achieved are the plasma current 168 KA, duration time of 920 ms and plasma linear-averaged density of 1.7 × 10 19 m −3 . The impurities, especially of low Z , are clearly decreased during the divertor experiments.

Characterization for Fusion Candidate Vanadium Alloys

This paper summarizes recent achievements in the characterization of candidate vanadium alloys obtained for fusion in the framework of the Japan-China Core University Program. National Institute for Fusion Science (NIFS) has a program of fabricating high-purity V-4Cr-4Ti alloys. The resulting products (NIFS-HEAT-1,2), were characterized by various research groups in the world including Chinese partners. South Western Institute of Physics (SWIP) fabricated a new V-4Cr-4Ti alloy (SWIP-Heat), and carried out a comparative evaluation of hydrogen embrittlement of NIFS-HEATs and SWIP-Heat. The tensile test of hydrogen-doped alloys showed that the NIFS-HEAT maintained the ductility to relatively high hydrogen levels. The comparison of the data with those of previous studies suggested that the reduced oxygen level in the NIFS-HEATs should be responsible for the increased resistance to hydrogen embrittlement. Based on the chemical analysis data of NIFS-HEATs and SWIP-Heats, neutron-induced activation was analyzed in Institute of Plasma Physics (IPP-CAS) as a function of cooling time after the use in the fusion first wall. The results showed that the low level of Co dominates the activity up to 50 years followed by a domination of Nb or Nb and Al in the respective alloys. It was suggested that reduction of Co and Nb, both of which are thought to have been introduced via cross-contamination into the alloys from the molds used should be crucial for reducing further the activation.

Liquid Metal Blanket-Related Issues Research in SWIP

In the last decade, liquid metal (LM) blanket-related key issues, such as the magnetohydrodynamics due to reactor off-normal shutdown, LM velocity two-dimensional effect, manifold three-dimensional effect, insulator coating imperfection effect, and so on, have been investigated in experiments and theoretic analysis in Southwestern Institute of Physics (SWIP). Some results were first observed such as the two-dimensional effect and the instabilities due to insulator coating imperfection in this field. These results also related to the advanced limiter-divertor plasma system. In this paper, we review the progress made by SWIP in this research field.

Perspective on fusion research in China: (1) efforts on nuclear fusion and plasma application in SWIP

The former Director of the Southwestern Institute of Physics, Academician Li Zengwu had suggested to the Chinese Government to promote the Nuclear Fusion Research in 1955. In the beginning of 1958, the research of nuclear fusion as future energy resources had been set up as the Fourteenth Division of China Atomic Energy Science Institute in Beijing and the Physics Institute Academy Sinica in Beijing. At the end of 1958, the East-northern Technique Physics Institute in Ha-re-bin was set up as the first institute engaged in nuclear fusion in China and then the Southwestern Institute of Physics was founded in 1965. At the beginning of this Institute, the θ-pinch, Mirror and Tokamak Research were carried on in parallel. Since 1985, the spin-off of fusion technology has been looked as an important field to make contribution to national economics and fusion effort was concentrated on Tokamak at the same time. The HL Tokamak is a general name of fusion project being carried on in Southwestern Institute of Physics, China National Nuclear Corporation. Related fusion technologies are ongoing simultaneously. The outline of HL Tokamak project and the highlights of experimental results obtained on HL-1 and HL-1M are given in this paper. In addition, the fusion efforts made important contributions to a variety of areas. Applications of fusion spin-off technologies, particularly of plasma technologies, are also described briefly in this paper.

Fusion research activities in China

The fusion program in China has been executed in most areas of magnetic confinement fusion for more than 30 years. Basing on the situation of the power supply requirements of China, the fusion program is becoming an important and vital component of the nuclear power program in China. This paper reviews the status of fusion research and next step plans in China. The motivation and goal of the Chinese fusion program is explained. Research and development on tokamak physics and engineering in the Southwestern Institute of Physics (SWIP) and the Institute of Plasma Physics of Academic Sinica (ASIPP) are introduced. A fusion breeder program and a pure fusion reactor design program have been supported by the State Science and Technology Commission (SSTC) and the China National Nuclear Corporation (CNNC), respectively. Some features and progress of fusion reactor R&D activities are reviewed. Non fusion applications of plasma science are an important part of China fusion research; a brief introduction about this area is given. Finally, an introductional collaboration network on fusion research activities in China is reported.

Plasma source ion implantation project at Southwestern Institute of Physics

The characteristics and use of the first plasma source ion implantation (PSII) device (PSII-EX) put into operation in the Southwestern Institute of Physics (SWIP) in 1993 are described. Experiments performed with this device have demonstrated its use for achieving good uniform surface-modification properties of materials via ion implantation. These properties include improvements in surface microhardness, friction and the biological compatibility of Ti alloy materials. In addition, PSII treatment of practical workpieces, such as cutting tools, measuring tools and bearings, have also led to substantial improvements in wear life. Surface analyses of treated samples have been performed using TEM, AES, XPS and RBS. Computer simulation of the PSII process has been used to assist our research. PSII technology is being developed for industrial and commercial applications via a novel industrial PSII machine and new modification techniques that are being developed using this machine at SWIP.

Fusion reactor design and technology program in China

Abstract A fusion–fission hybrid reactor program was launched in 1987. The purpose of development of the hybrid reactor is twofold: to solve the problem of nuclear fuel supply for an expected large-scale development of fission reactor plants, and to maintain the momentum of fusion research. The program is described and the activities and progress of the program are presented. Two conceptual designs of an engineering test reactor with tokamak configuration were developed at the Southwestern Institute of Physics and the Institute of Plasma Physics. The results are a tokamak engineering test breeder (TETB) series design and a fusion-fission hybrid reactor design (SSEHR), characterized by a liquid-Li self-cooled blanket and an He-cooled solid tritium breeder blanket respectively. In parallel with the design studies, relevant technological experiments on a small or medium scale have been supported by this program. These include LHCD, ICRH and pellet injection in the area of plasma engineering; neutronics integral experiments with U, Pu, Fe and Be; various irradiation tests of austenitic and ferritic steels, magnetohydrodynamic (MHD) pressure drop experiments using a liquid metal loop; research into permeation barriers for tritium and hydrogen isotopes; solid tritium breeder tests using an in-situ loop in a fission reactor. All these experiments have proceeded successfully. The second step of this program is now starting. It seems reasonable that most of the research carried out in the first step will continue.

Low energy broad beam multipole ion source

A low energy broad beam multipole ion source has been successfully developed at the Southwestern Institute of Physics, which can be used for both sputtering deposition and direct ion beam deposition. The extracted A+r beam current is 30–250 mA at a beam energy of 200–6000 eV. It has been used for sputtering deposition at the three beam synchronously mixing machine in Dalian University of Technology.

Development of plasma source ion implantation in China

In recent years, the plasma source ion implantation (PSII) technique has been developed in China. It is called all orientation ion implantation. Experimental devices have been built in Harbin Institute of Technology, Southwestern Institute of Physics, Dalian University of Technology, Sichuan University, and China Textile University, respectively. In this article, two typical devices are described, preliminary results of the PSII-ion beam enhanced deposition and production of diamondlike carbon films, and some computer simulation programs are reported briefly. Some experiments show that addition of rare-earth metal ions, or heavy metal ions, or Xe+, Kr+ in the nitrogen plasma may make the effectiveness of the surface modification better. Future considerations are also described in the article.