A repetitive pellet injection system for steady state fuelling in EAST superconducting tokamak

Li, C.Z.; Hu, Jiansheng; Chen, Y.; Vinyar, I.; Li, J.G.; Lukin, A. Ya.

doi:10.1016/j.fusengdes.2013.12.059

Cited by 29 publications

(25 citation statements)

References 7 publications

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“…The RMP coil current and voltage can be up to 2.5 kA and 600 V, respectively. Apart from gas puffing and SMBI [24], EAST has been equipped with a 10 Hz deuterium pellet injection system since 2012 [25]. It can inject pellets with both the length and diameter of 2 mm at 100 ~ 300 m/s velocity at a maximum frequency of 10 Hz with a reliability of over 95% for more than 1000 s with steady-state from either the LFS or HFS.…”

Section: Methodsmentioning

confidence: 99%

Density compensation and stored energy recovery in resonant magnetic perturbation suppressed edge-localized mode H-mode plasmas using pellet fueling on EAST

Hou

Chen

et al. 2019

Nucl. Fusion

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The fueling of plasmas using frozen pellets in steady-state quiescent H-mode plasmas with edge-localized modes (ELMs) suppressed by external magnetic perturbations (RMPs) was successfully demonstrated on the EAST tokamak in plasmas with similar shapes to those in ITER with q 95 ~ 3.8, and triangularity δ ~ 0.45. During the fully suppressed-ELM phase using RMPs, the plasmas were refueled by deuterium pellets with a frequency of 5 Hz from ~40 cm above the mid-plane on the low field side. The results show that the pellet fueling would partially compensate density, which decreased due to the effect of pump-out induced by RMPs. It was interesting to discover that the stored energy of the plasma could be raised to the value from before RMP application using pellet injection, which is rarely reported in other tokamaks. As for ELMs, they reappeared with a size smaller than the ELMs before RMP application accompanied with a magnetic coherent mode termination, however, the ELMs were still mitigated to a certain extent. Meanwhile, a similar experiment using supersonic molecular beam injection fueling was also carried out, which confirmed that pellet fueling is better for raising plasma stored energy. This investigation on the synergistic effect of pellet fueling and RMPs would be useful for simultaneous control of plasma density and ELMs in high performance H-mode plasmas in future devices, such as ITER.

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Section: Methodsmentioning

confidence: 99%

Density compensation and stored energy recovery in resonant magnetic perturbation suppressed edge-localized mode H-mode plasmas using pellet fueling on EAST

Hou

Chen

et al. 2019

Nucl. Fusion

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“…PELIN LLC designed the pellet injector for EAST on the basis of earlier injectors developed for plasma fuelling on other fusion devices [8−10] . The injector [11] is cooled by liquid helium and able to produce hydrogen or deuterium ice rods continuously for more than 1000 s. Pellets are formed repetitively when an electromagnetic cutter slices off solid hydrogen/deuterium rods at various frequencies. At the same time, a fast valve provides a portion of high-purity helium propellant gas to accelerate the pellet.…”

Section: Methodsmentioning

confidence: 99%

First Results of Pellet Injection Experiments on EAST

2014

Plasma Sci. Technol.

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A new pellet injection system was installed on the EAST tokamak and preliminary experiments were performed during the 2012 run campaign. Typical phenomena associated with deuterium pellet injection into a plasma discharge have been observed including sudden increases of the electron density and Hα/Dα emission intensity as well as a significant decrease in plasma electron temperature. Profiles have been studied in order to understand the influence of pellet fuelling on EAST discharges. Even though the injector was specifically designed for plasma fuelling, ELM triggering using the pellet injection has also been tested. In order to find appropriate parameters for triggering ELMs in H-mode plasmas, scanning of the pellet injection speed was employed for pellets injected from both the high field side and low field side of the plasma column. It has been observed that low-speed pellets injected into H-mode plasma from the low-field side could trigger an ELM followed by a number of smaller induced ELMs at about 300 Hz.

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“…This 50 Hz pellet injection system was developed in cooperation between ASIPP (China) and PELIN (Russia). Compared to the previous 10 Hz pellet injection system (PI-20) [8], the new system can operate either from 1−25 Hz with one injection module or from 1−50 Hz with both injection modules. Each module, which consists of a screw extruder and a pellet fabrication and acceleration system, can independently accomplish the whole pellet fabrication and acceleration process.…”

Section: Hz Pellet Injection System Figure 1 a 3d View Of The 50 Hz Pellet Injectormentioning

confidence: 99%

“…The pumping system for the 50 Hz pellet injection system was designed based on the preliminary results [9] and the PI-20 pumping system [8], as shown in figure 5.…”

Section: Design Of the Pumping Systemmentioning

confidence: 99%

Development and integration of a 50 Hz pellet injection system for the Experimental Advanced Superconducting Tokamak (EAST)

Yao

Chen

et al. 2017

Fusion Engineering and Design

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A 50 Hz pellet injection system, which is designed for edge-localized mode (ELM) control, has been successfully developed and integrated for the Experimental Advanced Superconducting Tokamak (EAST). Pellet injection is achieved by two separated injection system modules that can be operated independently from 1−25 Hz. The nominal injection velocity is 250 m/s with a scatter of ±50 m/s at a repetition rate of 50 Hz. A buffer tank and a two-stage differential pumping system of the pellet injection system was designed to increase hydrogen/deuterium ice quality and eliminate the influence of propellant gas on plasma operation, respectively. The pressure of the buffer tank could be pumped to 1×10 2 Pa, and the pressure in the second differential chamber could reach 1×10 -4 Pa during the experiment. Engineering experiments, which consisted of 50 Hz pellet injection and guiding tube mock-up experiments, were also systematically carried out in a laboratory environment and demonstrated that the pellet injection system can reliably inject pellets at a repetitive frequency of 50 Hz.

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A repetitive pellet injection system for steady state fuelling in EAST superconducting tokamak

Cited by 29 publications

References 7 publications

Density compensation and stored energy recovery in resonant magnetic perturbation suppressed edge-localized mode H-mode plasmas using pellet fueling on EAST

Density compensation and stored energy recovery in resonant magnetic perturbation suppressed edge-localized mode H-mode plasmas using pellet fueling on EAST

First Results of Pellet Injection Experiments on EAST

Development and integration of a 50 Hz pellet injection system for the Experimental Advanced Superconducting Tokamak (EAST)

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