TJ-II:Real Time Lithiation-boronization in TJ-II

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Experimental campaign

2019 Autumn

Proposal title

Real Time Lithiation-boronization in TJ-II

= Name and affiliation of proponent

F Tabares

Details of contact person at LNF

If applicable, enter contact person here or write N/A

Description of the activity

Two techniques for real time boronization will be tried: a)Injection of H2/o-carborane through a heated puffing valve and b)Dropping B spheres from the top of the machine by a vibrating oscillator (modified Veeco valve). The second one will be also used with Li microspheres as done in other devices. Real time conditioning techniques have a high potential for application to steady state plasma operation (next generation of SC devices). Boronization by powder dropping in W7X and AUG and lithiation by Li injector in NSTX, EAST, etc, following the successful experience of the DOLLOP technique in TFTR . The aim of the proposal in TJ-II is to check if wall lithiation and boronization can be substituted by short, real time injection of Li and B dust during plasma operation, so that the build up of flaking Li films can be avoided.Requirements. High density plasmas (NBI) seem better suited due to a lower perturbation of the line density by the injected B/Li, although power balance considerations may suggest otherwise (ECRH). Frequent entrances to the TJII hall are foreseen at the beginning. Characteristic signatures of FW state (recycling, density control, impurities, radiation, etc) will be monitored.

[1] A. Nagy, et al., A multi-impurity powder dropper for fusion applications, Rev. Sci. Instrum. 89 (2018) 10K121. [2] A Bortolon et al. Real-time wall conditioning by controlled injection of boron and boronnitride powder in full tungsten wall ASDEX Upgrade. Nuclear Materials and Energy 19 (2019) 384–389

== International or National funding project or entity S1. Wall Conditioning

Description of required resources

Required resources:

  • Number of plasma discharges or days of operation:
  • Essential diagnostic systems:
  • Type of plasmas (heating configuration):
  • Specific requirements on wall conditioning if any:
  • External users: need a local computer account for data access: yes/no
  • Any external equipment to be integrated? Provide description and integration needs:

Preferred dates and degree of flexibility

Preferred dates: (format dd-mm-yyyy)

References

[1] A. Nagy, et al., A multi-impurity powder dropper for fusion applications, Rev. Sci. Instrum. 89 (2018) 10K121. [2] A Bortolon et al. Real-time wall conditioning by controlled injection of boron and boronnitride powder in full tungsten wall ASDEX Upgrade. Nuclear Materials and Energy 19 (2019) 384–389



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