Surface Enhanced Exchange Reactions of Hydrogen Isotopes with Water and Fomblin Oil

Maintaining isotopic purity of tritium is one of the major tasks in several new large facilities such as ITER (International Thermonuclear Experimental Reactor), KATRIN (Karlsruhe Tritium Experiment) and NEXTEX (Texas Neutrino Mass Experiment). Working with multiple isotopes and isotopomers is always accompanied by isotope exchanges, which are accelerated by catalysts. These are provided by surfaces of various materials, which are used in the recycling systems. Here new results are reported of the solubility of hydrogen in Fomblin oil and kinetics for reactions between D₂O, HDO, H₂O and D₂, HD and H₂ taking place at the surface of a stainless steel (SS304) vessel at pressures of about 350 Pa. The kinetics of hydrogen isotopes were measured by Raman spectrometer. The water isotopomers were monitored by mass spectrometry. The solubility of hydrogen in Fomblin oil was determined at several H₂ pressures using NMR spectroscopy. The results can be extended to lower pressures using Henry's law.