Improvement of the Procedure for Monitoring Iodine Radionuclides in Off-Gases from Nuclear Power Facilities

Epimakhov, V. N.; Москвин, Л. Н.; Chetverikov, V. V.; Oleinik, M. S.; Mysik, S. G.

doi:10.1134/s106636221803013x

Cited by 2 publications

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“…Ionic forms (I – , IO 3 – ) are not volatile and exist primarily in aqueous systems, but they may form during the capture of the volatile iodine-containing compounds as they interact with the capturing medium. While several iodine species have already been studied for off-gas scrubbing applications, ,,− methods to better characterize iodine scrubbing performance in situ and in real time are needed to better understand and optimize treatment systems.…”

Section: Introductionmentioning

confidence: 99%

Iodine and Carbonate Species Monitoring in Molten NaOH–KOH Eutectic Scrubber via Dual-Phase In Situ Raman Spectroscopy

et al. 2022

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Molten hydroxide scrubbing of off-gas vapors is a potential process to improve safety during the operation of generation IV molten salt nuclear reactors (MSRs). MSRs produce off-gases that can be vented by the reactor core and treated via off-gas scrubbers. Molten hydroxide scrubbers focus on capturing volatile iodine radionuclides, and they can also be used to capture aerosols and particulates and to neutralize acidic species. The performance of these scrubbers depends on the chemical interactions of the scrubbing medium with the off-gas species. Knowledge of the concentration and speciation of scrubbed or target species, as well as process and environmental interferents, can enable advanced operation of MSR off-gas treatment systems. Optical online monitoring is an excellent technology to provide this information in real time, while limiting the need for operators to interact with radioactive samples through hands-on interrogation. Raman spectroscopy can provide crucial chemical information on the state of the molten eutectic during treatment in the molten phase, as well as the gas phase. In this work, Raman spectroscopy is used to detect iodine species, specifically iodate, in the molten phase of a NaOH−KOH eutectic and to construct a calibration curve of the Raman signal of those species. Additionally, a carbonate interferent is followed from the gas phase to the liquid phase as a basis for reaching a Raman-aided mass balance of the molten hydroxide eutectic scrubber system.

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