Tritium enrichment of environmental waters by electrolysis

In order to enrich the tritium in the water samples by minimum 10 times, we have developed a battery of 5 electrolysis cells. The procedure for electrolytic tritium enrichment of water requires that both isotopic fractionation during the sample treatment and contamination with other water, possibly of high 3H concentration, be excluded. The procedure includes, before the enrichment run, a primary distillation of the samples and after the enrichment a final distillation. During distillation the temperature should be about 150 deg C and the recovery of water total. We have used a method known from the literature for the estimation of the enrichment factor for the tritium content in the water samples after electrolysis (β) by means of the enrichment factor for the deuterium content (α) that is measured before and after the electrolysis by mass spectrometry. The tritium enrichment factor, β, is determined by using the Bigeleisen relation, lgβ = 1.41 lgα, in the limits of ±5% errors. In order to obtain a desired final volume in every cell we have developed a programmable electronic system that can interrupt the current through any cell in which the desired volume of electrolyte is attained. We have obtained an enrichment factor of 20 for the water samples after electrolysis. (author)