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SUMMARY:"Deuterium Retention and Plasma Characterization"
DTSTART:20130603T103000
DTEND:20130603T113000
DTSTAMP:20260414T132348Z
UID:88f54d5e6119e5c47aea06b6acda568deb7230d3da60de060a32802b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Yangyang Zhang - University of Gent\, B\nDeuterium-Tritium rea
 ction has the biggest reaction cross section among other fusion reactions.
  This scenario requires fuel control to be 50% D and 50% T. Retention\, ho
 wever\, could break this fuel ratio balance and cause big problem to fuel 
 control system. During tokamak operation\, deuterium and tritium could go 
 into first wall materials (mainly divertor region)\, leading to fuel loss 
 and also the fuel inside of the first wall material could go into main pla
 sma\, causing additional fuelling. What more\, for safety reason\, the tri
 tium inventory in ITER is strictly limited to 700g.\nHere presented the de
 uterium retention study on Plasmatron VISIONI in SCK·CEN\, Mol\, Belgium.
  Deuterium (also mixture of nitrogen) plasma is generated through glow dis
 charge\, with typical parameters of Te=10eV\, f=100V. The tungsten sample 
 is used as the function of plan probe\, which is connected to power source
  of -80V. The typical ion flux is f=1021 ion m-2s-1 and probe temperature 
 is Tp=350˚C. Plasma is in non-thermal state and the ion energy is dominat
 ed by Bohms criterian\, which is 1/2miv22=eDf+1/2Tee. SEM shows bubbles fo
 rmed during pure deuterium exposure on the surface of tungsten samples. 5%
  nitrogen exposure also shows bubbles formed. 1% nitrogen exposure\, howev
 er\, shows a clear decrease of bubbles. The reason may be the relative hig
 h sample temperature Tp=350˚C (5% nitrogen exposure has a temperature dro
 p in the end of the exposure despite of the same Tp with 1% exposure). XPS
  results shows high probe temperature (Tp=350˚C) could prevent tungsten-n
 itrogen chemical reaction. W-N chemical bunding appears at probe temperatu
 re around 250˚C. TDS is undergoing and the result will be included.
LOCATION:CRPP\, PPB 019
STATUS:CONFIRMED
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