Operation

 

The ‘JT-60SA Research Plan’ summarizes research objectives and strategy of JT-60SA experiments covering all the major research fields contributing to ITER and DEMO:

 
 
  1. Operation Regime Development
  2. MHD Stability and Control
  3. Transport and Confinement
  4. High Energy Particle Behaviour
 
  1. Pedestal and Edge Physics
  2. Divertor, Scrape Off Layer and Plasma-Material Interaction
  3. Fusion Engineering
  4. Theoretical Models and Simulation Codes
 
 

The purpose of discussing the JT-60SA Research Plan is not only for maturing this Research Plan itself, but also for encouraging integrated fusion research including ITER, JT-60SA, modelling and theory, on the devices leading towards DEMO.

 
 

This research plan has been evolved in the fusion communities in Japan and Europe to deepen and sharpen the research strategy of JT-60SA. At present, the EU/JA Integrated Project Team of the Satellite Tokamak Project, Eurofusion and Fusion Energy Forum Japan are collaborating as the JT-60SA Research Unit for establishment of the research plan.

The final version ‘JT-60SA Research Plan Version 4.0‘ was completed in September 2018. This version 4.0 has matched the SARP with the new ITER Research Plan. Major objectives of the Initial Research Phases I and II of JT-60SA are defined with priority in terms of scenario developments and risk mitigations for ITER and DEMO. For the long term, the strategy of transition from carbon wall to tungsten wall is described. The tungsten wall experiment will start in 2030 after achieving the JT-60SA‘s main mission of high-beta full non-inductive steady-state operations and before the start of the ITER full power phase of H/He (PFPO-II) in 2031. This transition to the tungsten wall has become the Project Baseline of JT-60SA.

 
 
 

Thus the experiment will be operated in phases gradually building up its capability for the enhanced research phase.

The plasma performance range expected for JT-60SA is shown on the diagram, in comparison with existing experiments worldwide as well as with expected ITER and DEMO operation.

 
 

The JT-60SA device is capable of confining break-even-equivalent class high-temperature deuterium plasmas lasting for a duration (typically 100 s) longer than the time scales characterizing key plasma processes, such as current diffusion and particle recycling. The maximum plasma current is 5.5 MA.

 

The device also pursues fully non-inductive steady-state operations with high values of the plasma pressure exceeding the plasma stability limits without wall-stabilization.

 
     
 

JT-60SA enables experiments at ITER and DEMO-relevant plasma regimes in terms of non-dimensional plasma parameters and DEMO-equivalent high plasma shape parameter. ( The three non-dimensional plasma parameters, normalized poloidal gyro radius ρ*, collisionality ν*, and the plasma pressure measure βN determine the plasma processes.)

 
     
 

In DEMO reactors, we need to sustain high values of the energy confinement improvement factor (the HH-factor), the normalized beta βN, the bootstrap current fraction, the non-inductively driven current fraction, the plasma density normalized to the Greenwald density, the fuel purity, and the radiation power simultaneously in steady-state. However, such a high ‘integrated performance’ has never been achieved. The most important goal of JT-60SA for DEMO is to demonstrate and sustain such integrated performance, and to decide the acceptable DEMO plasma design including practical and reliable plasma control schemes suitable for a power plant. The central DEMO design reference for JT-60SA is an ‘economically attractive (= compact) steady-state’ reactor. However, the JT-60SA Research Plan treats the ‘wide DEMO regime’ as a spectrum of plausible operating states.

 
 

 
 
© JT-60SA