Adsorption properties of iodine on fused silica surfaces when evaporated from tellurium in various atmospheres
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Adsorption properties of iodine on fused silica surfaces when evaporated from tellurium in various atmospheres Erik Karlsson1,2 · Jörg Neuhausen1 · Robert Eichler1,2 · Alexander Vögele1 · Andreas Türler2 Received: 9 June 2020 © The Author(s) 2020
Abstract The evaporation of iodine containing species from tellurium has been investigated together with their adsorption behavior on a fused silica surface. In inert gas, the formation of two species was observed with adsorption enthalpies of around − 90 to − 100 and − 110 to − 120 kJ/mol, respectively. For reducing environments, a single species identified as monatomic iodine was observed with an adsorption enthalpy around − 95 kJ/mol. In oxidizing conditions, species with low adsorption enthalpies ranging from − 65 to − 80 kJ/mol were observed. Presumably, these are iodine oxides as well as oxo-acids of iodine (HIOx). The results of the thermochromatography experiments performed here prove the usefulness of the employed production method for carrier-free iodine isotopes and enhance the understanding of the evaporation and deposition behavior of iodine under various chemical conditions. Keywords Iodine · Tellurium · Thermochromatography · Fused silica · Adsorption
Introduction With upwards of 450 currently operating nuclear power reactors worldwide, the waste problem is becoming an increasing worry. One of the possible ways to deal with this problem efficiently is introducing a nuclear reactor concept that is capable of treating the spent nuclear fuel through transmutation to reduce the required storage time. Such reactors require different components compared to light-water reactors, such as a coolant that is adapted for fast neutrons to facilitate transmutation. To achieve the goal of efficient transmutation of nuclear fuel on a large scale, research is proceeding in several projects, one of them being the MYRRHA-reactor [1]. The MYRRHA-reactor is a lead-bismuth eutectic (LBE) cooled fast neutron spectrum reactor constructed as a research and training facility as a well as a proof of concept. Novel reactor systems require licensing procedures to be performed, which include a thorough look at the chemistry of potential radiological hazards. One of these * Jörg Neuhausen [email protected] 1
Laboratory of Radiochemistry, Paul Scherrer Institut (PSI), Forschungsstrasse 111, 5232 Villigen, Switzerland
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
2
most prominent radiological hazards are iodine isotopes produced through fission. The behavior of these radionuclides have been extensively studied in classic light-water reactor systems. However, the adsorption behavior in a lead-bismuth based system is so far unexplored. Studies have been performed on the evaporation of iodine from a dilute solution in LBE in an inert (Ar/5%H2) atmosphere. One of the studies found significant volatilization occurring around 800 K in an inert atmosphere (Ar/5%H2) [2], however another found release temperatures around 700
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