Integration of Dual Mass Spectrometry for Tritium Registration in Experiments with Lithium Metatitanate at the IVG.1M Research Reactor

Lithium-containing ceramics, such as lithium metatitanate and lithium orthosilicate, are candidate materials for solid breeder blanket modules in future fusion reactors. An important aspect of their application in fusion reactors is the accurate registration of tritium produced under irradiation, which is required for assessing tritium behavior and release characteristics. In this work, an irradiation ampoule device was developed and fabricated for reactor experiments with highly enriched lithium metatitanate pebbles (Li2TiO3 +5 mol % TiO2, up to 96% by 6Li). The device was installed in a physical experimental channel of the IVG.1M research reactor (Kurchatov, Kazakhstan) and equipped with K-type thermocouples for monitoring the sample temperature during irradiation. Reactor experiments were performed according to an approved experimental program at reactor thermal power levels of 1, 3, and 6 MW. During irradiation, tritium-containing molecules (HT and T2) released from the pebble bed samples were continuously registered in situ using a vacuum extraction method. Tritium measurements were carried out by integrating two mass spectrometers—HIDEN Analytical Ltd. and RGA-100 (Stanford Research Systems)—into the LIANA experimental facility, which represents the main novelty of this work and improves the reliability of tritium registration. The temperature dependence of the partial pressures of tritium-containing molecules was investigated under reactor irradiation at different power levels. The main outcomes of this work include successful testing of the tritium registration method based on dual mass spectrometry, confirmation of the obtained experimental data, and determination of the temperature conditions governing tritium generation and release from lithium metatitanate pebbles.