The reaction of carbon oxides and hydrogen in the presence of the Raney nickel catalyst has been used for water synthesis. A procedure has been developed for the recovery and collection of the synthesized water with minimal losses and without deteriorating the 17O or 18O isotope enrichment as compared to the initial CO2 and CO. The recovery of oxygen with high concentrations of 17O and 18O isotopes is based on the reaction of xenon difluoride with water. The yield based on oxygen achieves 99% without reduction of isotope enrichment, which is confirmed by mass-spectral measurements of oxygen isotope concentrations in the initial reagents and final reaction products.