APRI 10 - Studies of Tellurium, Molybdenum, Iodine and other important volatile fission products during severe nuclear ractor accidents

Forskningsprojekt, 2018 – 2020

Proper examination of iodine and cesium reactivity towards metallic fission products is thus necessary to increas the accuracy of todays poorly modeled chemical systems in the case of a nuclear accident.

This part is intended to lay the groundwork for future studies on this topic. As a starting point four metal will be investigated, molybdenum, tellium, ruthenium and niobium. Of these niobium, usually is not released during nuclear accident to a significant level. During the Fukushima accident this was not the case. Unexpected releases of niobium were observed and one reason considered was the formation of niobium halides.

The experiment planned would be performed by heating in a tubular furnace, each individual metal proposed in powder form inside ceraic crucible. The desired temperature would then be reached in stagnat inert nitrogen atmosphere. After reaching desired temperature the gas flow will be initiated. Initially, this gas flow will only consist of air, simulating oxidizing conditions. Later, addition of either iodine or cesium iodide to investigate the oxyhalide formation.

Analysis will be done to determine mass changes (ICP-OES) abd formation of new species (XRD, XPS) included by iodine and cesium iodide addition to the air on the metallic powder. Both a filter at the tube outlet and cold-trap containing NaOH at the system outlet will also be analyzed. To determine the aerosols and transport behavior.