Investigations on the thermal release of iodine from liquid eutectic lead-bismuth alloy

Neuhausen, Jörg; Eichler, Β.

doi:10.1524/ract.2006.94.5.239

Cited by 11 publications

(7 citation statements)

References 5 publications

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“…Iodine is commonly believed to be well retained in lead alloy coolants [3]. To verify this claim, we have characterized iodine evaporation from dilute solution in LBE by the so-called transpiration method and confirmed, consistent with experiments at much lower concentrations using a different source of iodine [19], that iodine evaporation from LBE is indeed strongly suppressed compared to evaporation of pure iodine.…”

Section: Fission and Spallation Product Chemistry And Evaporationsupporting

confidence: 59%

The LBE Coolant Chemistry R&D Programme for the MYRRHA ADS: Chemistry and Control of Oxygen, Corrosion and Spallation Products

Aerts

Gladinez

Prieto

et al. 2020

Proceedings of the 14th International Workshop on Spallation Materials Technology

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Compatibility with structural materials and activation are major challenges of the use of heavy liquid metal (HLM) spallation targets and coolants such as lead-bismuth eutectic (LBE). Steel exposed to HLM is prone to corrosion which results in the release of steel elements in the HLM coolant. A commonly accepted strategy to reduce corrosion rates is to maintain a sufficiently elevated dissolved oxygen concentration in order to stabilize a protective oxide layer on the steel surface in contact with HLM. We present a brief overview of the oxygen sensing and control technology for LBE, developed in the frame of the MYRRHA accelerator driven system (ADS) demonstrate its performance on a large scale in the MEXICO chemistry loop (Mass Exchanger In Continuous Operation). MYRRHA stands for Multipurpose hYbrid Research Reactor for High-tech Applications accelerator driven system and is currently under development at the Belgian Nuclear Research Centre, and will operate between 200 °C and 400 °C with a target oxygen concentration level of 10-7 wt-%. Numerical simulations allowed mapping of the local oxygen concentration in MYRRHA, enabling identification of the regions in the core which could be prone to corrosion. On the other hand, oxygen concentrations must be sufficiently low to avoid formation of solid lead oxide (PbO) in the primary circuit. When designing a nuclear system such as an ADS, one must take into account accidents that may lead to increase of the oxygen concentration in the LBE and assess the probability for PbO formation and its consequences. In this context, we have studied the formation of lead oxide from oxygen-oversaturated LBE and determined the metastable limit for PbO nucleation. Corrosion products that are released in the LBE will interact with dissolved oxygen in LBE to form corrosion product oxides. These interactions influence the concentration of both dissolved oxygen and dissolved corrosion products. This in turn can cause changes in the corrosion process itself by altering the driving force for steel element dissolution or protective oxide layer decomposition. Experimental results will be presented which provide evidence for the precipitation and dissolution of oxides of iron impurities in LBE. Numerical simulations based on computational fluid dynamics (CFD) and chemical equilibrium complement experiments in understanding the interactions between coolant chemistry and reactor thermal-hydraulics. A similar approach was adopted for simulating the chemistry of spallation and other radioactive impurities in the primary LBE of MYRRHA. Simulations allow the prediction of released fraction, vapor composition and precipitation/dissolution phenomena in the LBE, as function of the oxygen concentration in the LBE and of the oxygen and humidity content of the cover gas in contact with the LBE. Simulations of the chemical behavior of several critical

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Section: Fission and Spallation Product Chemistry And Evaporationsupporting

confidence: 59%

The LBE Coolant Chemistry R&D Programme for the MYRRHA ADS: Chemistry and Control of Oxygen, Corrosion and Spallation Products

Aerts

Gladinez

Prieto

et al. 2020

Proceedings of the 14th International Workshop on Spallation Materials Technology

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“…Furthermore, also in the exhaust gas monitoring no large quantities of iodine isotopes were found [10]. Finally, in dedicated experiments on the evaporation of iodine from LBE [21] it was shown that significant evaporation occurs only at temperatures >500 ∘ C, much a Average of two calculations using different nuclear models. higher than the temperatures of the LBE free surface in the MEGAPIE target during operation (approx.…”

Section: Discussionmentioning

confidence: 99%

Radiochemical determination of ¹²⁹I and ³⁶Cl in MEGAPIE, a proton irradiated lead-bismuth eutectic spallation target

Hammer-Rotzler¹,

Neuhausen

Vockenhuber

et al. 2015

Radiochimica Acta

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Abstract:The concentrations of the long-lived nuclear reaction products 129 I and 36 Cl have been measured in samples from the MEGAPIE liquid metal spallation target. Samples from the bulk target material (lead-bismuth eutectic, LBE), from the interface of the metal free surface with the cover gas, from LBE/steel interfaces and from noble metal absorber foils installed in the cover gas system were analysed using Accelerator Mass Spectrometry at the Laboratory of Ion beam Physics at ETH Zürich. The major part of 129 I and 36 Cl was found accumulated on the interfaces, particularly at the interface of LBE and the steel walls of the target container, while bulk LBE samples contain only a minor fraction of these nuclides. Both nuclides were also detected on the absorber foils to a certain extent (≪ 1% of the total amount). The latter number is negligible concerning the radio-hazard of the irradiated target material; however it indicates a certain affinity of the absorber foils for halogens, thus proving the principle of using noble metal foils for catching these volatile radionuclides. The total amounts of 129 I and 36 Cl in the target were estimated from the analytical data by averaging within the different groups of samples and summing up these averages over the total target. This estimation could account for about half of the amount of 129 I and 36 Cl predicted to be produced using nuclear physics modelling codes for both nuclides. The significance of the results and the associated uncertainties are discussed.

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“…Studies have been performed on the evaporation of iodine from a dilute solution in LBE in an inert (Ar/5%H 2 ) atmosphere. One of the studies found significant volatilization occurring around 800 K in an inert atmosphere (Ar/5%H 2 ) [2], however another found release temperatures around 700 K [3]. The maximum coolant temperature of the MYRRHA is 723 K [4], so fractional evaporation of iodine is expected which merits studying it in more detail.…”

Section: Introductionmentioning

confidence: 99%

Adsorption properties of iodine on fused silica surfaces when evaporated from tellurium in various atmospheres

Karlsson

Neuhausen

Eichler

et al. 2020

J Radioanal Nucl Chem

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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.

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Investigations on the thermal release of iodine from liquid eutectic lead-bismuth alloy

Abstract: SummaryThe release of iodine from liquid eutectic lead-bismuth alloy (LBE) under a flowing Ar/7%H

Cited by 11 publications

References 5 publications

The LBE Coolant Chemistry R&D Programme for the MYRRHA ADS: Chemistry and Control of Oxygen, Corrosion and Spallation Products

The LBE Coolant Chemistry R&D Programme for the MYRRHA ADS: Chemistry and Control of Oxygen, Corrosion and Spallation Products

Radiochemical determination of ¹²⁹I and ³⁶Cl in MEGAPIE, a proton irradiated lead-bismuth eutectic spallation target

Adsorption properties of iodine on fused silica surfaces when evaporated from tellurium in various atmospheres

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Investigations on the thermal release of iodine from liquid eutectic lead-bismuth alloy

Abstract: SummaryThe release of iodine from liquid eutectic lead-bismuth alloy (LBE) under a flowing Ar/7%H

Cited by 11 publications

References 5 publications

The LBE Coolant Chemistry R&D Programme for the MYRRHA ADS: Chemistry and Control of Oxygen, Corrosion and Spallation Products

The LBE Coolant Chemistry R&D Programme for the MYRRHA ADS: Chemistry and Control of Oxygen, Corrosion and Spallation Products

Radiochemical determination of 129I and 36Cl in MEGAPIE, a proton irradiated lead-bismuth eutectic spallation target

Adsorption properties of iodine on fused silica surfaces when evaporated from tellurium in various atmospheres

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Radiochemical determination of ¹²⁹I and ³⁶Cl in MEGAPIE, a proton irradiated lead-bismuth eutectic spallation target