Determination of water leaks flows and their surface localization in plasma reactors by the ratio of the hydrogen isotopes line intensities

A high sensitive method of multispectral actinometry developed for the measurements of the concentration of minor hydrogen-oxygen products of plasma-chemical transformation of water is presented. It is shown that in presence of deuterium the correlation between H/D density ratio and the densities of other products is practically independent of non-equilibrium plasma conditions. It was studied in the hollow cathode experimental installation and model of the processes was developed for scaling purposes. This method allows to find the sources of water leaks to plasma due to the chamber wall defects and to measure their flow rates. The penetration of water vapors into the model installation was provided with a special localized leak and H/D ratio was measured by D-alpha and H-alpha lines intensity. The scaling was performed for the specific conditions of ITER reactor near-wall plasma during testing trials. The flows of the H2O, O-2, H-2, H, and O particles associated with the emergence of water molecules in plasma can be determined by observing disturbances suffered by the relative intensities of the emission spectral lines of particles in the vicinity of defects. The locality is limited by the spatial resolution of the optical system forming the image of the chamber wall. For testing purposes, discharge in an inert gas (He, 2.10(16) cm(-3)) with small additions of D-2 (10(12)-10(10)) cm(-3) is ignited in the near-wall region of the ITER chamber with electron concentrations and temperatures n(e) = (10(10)-10(13)) cm(-3), T-e = (4-30) eV. For this type of discharge water leaks with flows Q = (10(-13)-10(-9)) Pa m(3) s(-1) can be detected. Sensitivity improves with decreasing the amount of D-2 additives. With a complete examination of the internal surfaces of the chamber wall and the design requirement for the total water leakage Q < 10(-7) Pa m(3) s(-1), more than 100 small leaks with flows Q = (10(-11)-10(-9)) Pa m(3) s(-1) can be detected simultaneously.