Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Control of hydrogen content and fuel recycling for long pulse high performance plasma operation in EAST

Journal Article · · Nuclear Fusion
 [1];  [2];  [1];  [3];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics
  2. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics; Univ. of Science and Technology of China, Hefei (China)
  3. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics; Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
+ Show Author Affiliations
Control of fuel recycling and hydrogen content in the Experimental Advanced Superconducting Tokamak (EAST) using various methods is studied for high-power long pulse high confinement mode (H-mode) plasma operation. The results show that long duration first wall baking and discharge cleaning in EAST provides the necessary clean vacuum environment with a high ultimate vacuum of 3.6 × 10-6 Pa and low outgassing rate of ~1.5 × 10-4 Pa m3 s-1 for plasma operation. In-vessel cryopumps are found to provide an efficient method for particle recycling control in the divertor region to decrease global recycling coefficient (R global) from ~1.0 to ~0.8 during ohmic heating plasmas, and it provides a high particle exhausting rate of 1020_1021 D-atoms s-1 in high-power plasma operations. Long duration silicon coating is found to be more powerful than baking and discharge cleaning, which reduces the H/(H + D) ratio gradually to a value as low as 8%, and lithium coating is more effective and more efficient than silicon coating, to further reduce the H/(H + D) ratio to 3%. Real-time lithium powder injection is a novel method for recycling control, which reduces R global from 0.94 to 0.82 under lithium coating wall conditioning. By the combination and optimization of the above methods, H-mode plasmas with low hydrogen content and low fuel recycling have been achieved in EAST and have been extended gradually to 101 s in 2017. Recycling flux has even decreased gradually during 101 s H-mode plasmas due to increased first wall temperature and the resulting increased Li-II emission. These results provide valuable references on hydrogen content and fuel recycling control for long pulse H-mode plasmas of up to 400–1000 s with high-power heating in EAST and future fusion devices.
Research Organization:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE
Contributing Organization:
the EAST Team
Grant/Contract Number:
AC02-09CH11466
OSTI ID:
1619199
Alternate ID(s):
OSTI ID: 22930023
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 12 Vol. 59; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English

References (24)

The effect of divertor magnetic balance on H-mode performance in DIII-D journal March 2001
Plasma wall interaction during long pulse operation in Tore Supra journal March 1999
A simple apparatus for the injection of lithium aerosol into the scrape-off layer of fusion research devices journal November 2010
An overview of lithium experiments on HT-7 and EAST during 2012 journal December 2014
Influence of lithium coatings with large-area coverage on EAST plasma performance journal December 2014
Real-time reduction of tungsten impurity influx using lithium powder injection in EAST journal December 2018
Main chamber high recycling on ASDEX upgrade journal June 2009
Particle exhaust and recycling control by active divertor pumping in EAST journal August 2011
Real time wall conditioning with lithium powder injection in long pulse H-mode plasmas in EAST with tungsten divertor journal May 2019
Plasma-material interactions in current tokamaks and their implications for next step fusion reactors journal December 2001
Role of recycling flux in gas fuelling in the Large Helical Device journal December 2003
Global particle balance and wall recycling properties of long duration discharges on TRIAM-1M journal May 2004
Integration of high power, long pulse operation in Tore Supra in preparation for ITER journal September 2007
Dependence of the L–H transition on X-point geometry and divertor recycling on NSTX journal October 2013
Impact of minority concentration on fundamental (H)D ICRF heating performance in JET-ILW journal April 2014
Wall conditioning in fusion devices and its influence on plasma performance journal September 1996
Investigation of the origin of neutrals in the main chamber of Alcator C-Mod journal May 2002
Low-recycling conditions and improved core confinement in steady-state operation scenarios in JET (Joint European Torus) journal March 2013
Integrated Operating Scenario to Achieve 100-Second, High Electron Temperature Discharge on EAST journal April 2016
Investigation of hydrogen recycling in long-duration discharges and its modification with a hot wall in the spherical tokamak QUEST journal October 2017
New Steady-State Quiescent High-Confinement Plasma in an Experimental Advanced Superconducting Tokamak journal February 2015
Isolation of the Improved Core Confinement from High Recycling and Radiative Boundary in Reversed Magnetic Shear Plasmas of JT-60U journal February 1997
Enhanced Energy Confinement and Performance in a Low-Recycling Tokamak journal August 2006
Active Recycling Control Through Lithium Injection in EAST journal May 2018

Figures / Tables (13)

Fig. 1(p. 5)figure Fig. 1
Fig. 2(p. 5)figure Fig. 2
Fig. 3(p. 6)figure Fig. 3
Fig. 4(p. 7)figure Fig. 4
Fig. 5(p. 9)figure Fig. 5
Fig. 6(p. 10)figure Fig. 6
Fig. 7(p. 11)figure Fig. 7
Fig. 8(p. 12)figure Fig. 8
Fig. 9(p. 13)figure Fig. 9
Fig. 10(p. 14)figure Fig. 10
Fig. 11(p. 15)figure Fig. 11
Fig. 12(p. 16)figure Fig. 12
Fig. 13(p. 17)figure Fig. 13

Similar Records

Effect of lithium coating on long pulse high performance plasma discharges in EAST
Journal Article · Sun Jul 12 20:00:00 EDT 2020 · Plasma Physics and Controlled Fusion · OSTI ID:1830349
Fuel recycling and impurity characteristics in long-pulse H-mode plasmas with full metal and dynamically coated walls on EAST
Journal Article · Wed Aug 27 20:00:00 EDT 2025 · Nuclear Fusion · OSTI ID:2588130
Fuel recycling control in long pulse operation with full tungsten divertors in EAST tokamak
Journal Article · Thu Dec 01 19:00:00 EST 2022 · Nuclear Materials and Energy · OSTI ID:2420547

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
EAST
fuel recycling
hydrogen content
long pulse operation
wall conditioning