Thermochromatography study of volatile polonium species in various gas atmospheres

Maugeri, E. A.; Neuhausen, Jörg; Eichler, Robert; Piguet, D.; Schumann, D.

doi:10.1016/j.jnucmat.2013.11.024

Cited by 19 publications

(28 citation statements)

References 8 publications

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“…These conclusions are consistent with the identification of PoPb as a stable molecule which evaporates from both LBE and Pb-Li eutectic [58,9,4] and with the recent hypothesis of PoO being formed near the LBE [18]. In literature, PoH was not yet considered to be present near the LBE.…”

supporting

confidence: 88%

“…However, its presence is questionable on basis of its thermodynamical instability[2, 16,17]. More recently, the thermochromatography study of Maugeri [18] tentatively assigns observed 40 experimental signals to PoO, PoOH and PoO 2 . The latter molecule was previously reported by Abakumov [7], although it is not assumed to be stable in the cover gas above the LBE[2].…”

mentioning

confidence: 99%

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Binary and ternary Po-containing molecules relevant for LBE cooled reactors at operating temperature

Deyne

Rijpstra

Waroquier

et al. 2015

Journal of Nuclear Materials

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Quantum-chemical calculations at several levels of theory were used to assess the stability at different temperatures of a set of 13 binary and ternary Pocontaining molecules that could possibly be formed in an environment with lead, bismuth, oxygen and water. These are conditions that are relevant for a heavy liquid metal cooled fission reactor. The conclusions are that especially PoPb, PbPoO and PoOH and to a lesser extent Po 2 and PoO are stable. These small molecules are likely to be found near the Lead-Bismuth-Eutectic (LBE) coolant at operational temperatures. In contrast Po 3 and PoBi are unlikely to be present under the assumed conditions. Several stability criteria, such as the dissociation into free atoms or into molecular fragments at realistic Poconcentrations or in the thermodynamic limit are discussed at different temperatures. The results obtained with a medium level of theory (Density Functional Theory, PBE0 with Relativistic Effective Core Potentials) show good qualitative correspondence with calculations performed at a much higher level of theory (Multi Reference Configuration Interaction, with spin-orbit coupling and scalar relativistic Hamiltonian). This makes the medium level of theory to be a fair alternative, for obtaining at least qualitative insight, for a high level calculation method which is unfeasible for much larger systems.

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supporting

confidence: 88%

mentioning

confidence: 99%

Binary and ternary Po-containing molecules relevant for LBE cooled reactors at operating temperature

Deyne

Rijpstra

Waroquier

et al. 2015

Journal of Nuclear Materials

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“…Carrier free 206 Po was produced at the CERN-ISOLDE facility, where its precursor 210 Fr was implanted in thin (20 μm) gold foils (Goodfellow, 99.95 % purity) of 8 mm × 4 mm size in the same manner as described in Refs. [4,16].…”

Section: Sample Preparationmentioning

confidence: 99%

“…In addition, in particular conditions, polonium tends to form chemical species with high volatility, making this element even more harmful. Maugeri et al [4] reported the formation of more than one polonium species which are more volatile than the elemental polonium when moisture is present in inert and reducing atmosphere. Thus, the formation of volatile polonium species, induced by reactions with water, represents one of the main safety issues of an ADS [5,6].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of volatile polonium species on metals in various gas atmospheres: Part III – Adsorption of volatile polonium on stainless steel 316L

et al. 2017

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AbstractThis article summarizes the results obtained studying the interaction between polonium and stainless steel 316L in different atmospheres by the thermochromatography method. This issue is particularly important in terms of licensing of the MYRRHA prototype ADS reactor, where highly radiotoxic α-emitting polonium isotopes are produced in lead-bismuth eutectic used as both spallation target material and coolant, while stainless steel 316L is going to be the main structural material. The polonium adsorption enthalpy on stainless steel 316L in inert atmosphere was measured as −147±6 kJ mol−1. The findings obtained using reducing atmospheres show that the affinity of polonium for stainless steel 316L increases with the metallic character of the stainless steel surface. The presence of moisture in inert and reducing atmosphere does not significantly influence the polonium adsorption. Oxidizing atmospheres induce the formation of polonium dioxide which has a stronger interaction with the stainless steel 316L, with an adsorption enthalpy of −225±6 kJ mol−1. A prolonged exposure of the stainless steel to strong oxidants, such as pure oxygen, reduces the metallic character of the stainless steel surface and, consequently, its affinity to the polonium oxide. Furthermore, it was found that in all experiments at least 5 ppm of the total polonium present in the starting material were not retained on the stainless steel 316L surface at all.

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“…evaporation [7,8,9,10] or extraction [11,12] from LBE and the volatility of 35 polonium molecules [13,3]. Also the use of transition metals and noble metals as filter materials is a subject of study [14].…”

mentioning

confidence: 99%

Ab initio study of the trapping of polonium on noble metals

Rijpstra

Deyne

Maugeri

et al. 2016

Journal of Nuclear Materials

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In the future MYRRHA reactor, lead bismuth eutectic (LBE) will be used both as coolant and as spallation target. Due to the high neutron flux a small fraction of the bismuth will transmute to radiotoxic 210 Po. Part of this radiotoxic element will evaporate into the gas above the coolant. Extracting it from the gas phase is necessary to ensure a safe handling of the reactor. An issue in the development of suitable filters is the lack of accurate knowledge on the chemical interaction between a candidate filter material and either elemental polonium or polonium containing molecules. Experimental work on this topic is complicated by the high radiotoxicity of polonium. Therefore, we present in this paper a first-principles study on the adsorption of polonium on noble metals as filter

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Thermochromatography study of volatile polonium species in various gas atmospheres

Cited by 19 publications

References 8 publications

Binary and ternary Po-containing molecules relevant for LBE cooled reactors at operating temperature

Binary and ternary Po-containing molecules relevant for LBE cooled reactors at operating temperature

Adsorption of volatile polonium species on metals in various gas atmospheres: Part III – Adsorption of volatile polonium on stainless steel 316L

Ab initio study of the trapping of polonium on noble metals

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