Testing of the spectroscopic method for location of water microleakages in ITER at the L-2M stellarator

Abstract

Results of testing of a possible method for location of water microleakages in the cooling system of the first wall and vacuum chamber of ITER are presented. The method consists in spectroscopic detection of the emission lines of atoms and ions of the Xe additive dissolved in water. These lines are excited when the water with dissolved Xe contacts the plasma. The high electron cyclotron resonance heating (ECRH) power deposited in a relatively small plasma volume in the L-2M stellarator (P = 0.5 MW, V = 0.24 m3, and the specific heating power ∼2 MW/m3) makes it possible to achieve plasma parameters close to those in the edge plasma of ITER for different operating modes, including the H-mode with an edge transport barrier. In test experiments, several lines of Xe ions were revealed suitable for detection of xenon in plasma with parameters close to those in the edge plasma of ITER at leakage rates at a level of ∼10−6 Pa m3 s−1 and spatial resolution of ∼0.5 cm.