Isotopic Exchange for Metal Hydride Bed Disposal

For metal hydride bed disposal, tritium can be exchanged or replaced with deuterium or protium through successive dilution and removal. Analytical expressions are derived to describe the batch isotopic exchange process for metal hydrides with and without isotopic separation by the hydride. For the case without isotopic separation and the hydride being desorbed to the same gas inventory each exchange cycle, simple mathematical expressions are obtained. These equations can be used to estimate the number of exchange cycles needed to reduce the tritium content of a hydride to the desired inventory. Isotopic exchange predictions agreed with experimental results for La-Ni-Al alloys and titanium hydrides.