Adsorption of volatile polonium and bismuth species on metals in various gas atmospheres: Part I – Adsorption of volatile polonium and bismuth on gold

Abstract

<jats:title>Abstract</jats:title><jats:p>Polonium isotopes are considered the most hazardous radionuclides produced during the operation of accelerator driven systems (ADS) when lead–bismuth eutectic (LBE) is used as the reactor coolant and as the spallation target material. In this work the use of gold surfaces for capturing polonium from the cover gas of the ADS reactor was studied by thermochromatography. The results show that gaseous monoatomic polonium, formed in dry hydrogen, is adsorbed on gold at 1058 K. Its adsorption enthalpy was calculated as –250±7 kJ mol</jats:p>

Adsorption of volatile polonium species on metals in various gas atmospheres: Part II – Adsorption of volatile polonium on platinum, silver and palladium

“…Each irradiated disk was cut into small fragments containing between 5 and 20 kBq of 206 Po suitable for one thermochromatography experiment. Polonium was separated from the bismuth matrix and deposited on gold foils before starting the thermochromatography experiments by thermal release using a setup described [9]. Polonium deposited on the gold foils constitutes the starting materials for thermochromatography experiments.…”

“…The thermochromatography setup used for investigating the formation and deposition of polonium compounds on noble metals in different atmospheres is described [9]. The stationary phase consisted of a fused silica tube lined inside with foils of platinum, silver and palladium (Goodfellow, thickness 0.020 ± 0.003 mm, purity 99.9%), respectively.…”

“…The stationary phase consisted of a fused silica tube lined inside with foils of platinum, silver and palladium (Goodfellow, thickness 0.020 ± 0.003 mm, purity 99.9%), respectively. The setup, described in detail [9], was equipped with a carrier gas supply allowing for the use of different atmospheres, namely inert, reducing, oxidizing, moist, and dry. The inert (He) and reducing (H 2 ) carrier gases were passed through a purification system consisting of a P 2 O 5 cartridge and a Ta getter heated to 1273 K to remove moisture and oxygen.…”

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

“…[5,7,8], or to permanently absorb it from the gas plenum above the LBE using dedicated filter materials. For the latter purpose, the first two papers of this series studied the interaction of polonium with different noble metals as candidates for filtering materials [9,10].…”

“…The present investigation was carried out using the thermochromatography method (TC) [14,15]. A detailed description of the method used is given in the first papers of this series [9,10].…”