Deposition of RuO4 on various surfaces in a nuclear reactor containment

Holm, Joachim; Glänneskog, Henrik; Ekberg, Christian

doi:10.1016/j.jnucmat.2009.03.047

Cited by 18 publications

(7 citation statements)

References 19 publications

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“…From the values in Table 9 it is clear that the BE is not only dependent on the oxidation state of ruthenium but also on the chemical environment, e.g., the hydration of RuO 2 . Similar observations were also made in a previous study [ 29 ].…”

Section: Resultssupporting

confidence: 92%

Effect of nitrogen compounds on transport of ruthenium through the RCS

Kajan

Kärkelä

Auvinen

et al. 2017

J Radioanal Nucl Chem

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Ruthenium is a fission product that can be released from the fuel in case of a severe nuclear accident. In this work the impact of the atmosphere composition, including air radiolysis products, on the transport of ruthenium through a primary circuit was examined. Experiments were performed at temperatures 1300, 1500 and 1700 K in a slightly humid air. In the experiments significant effect of nitrogen oxides (N2O, NO2) and nitric acid on the ruthenium chemistry in the model primary circuit was observed. The obtained results indicate a strong effect of air radiolysis products on the quantity partitioning of transported ruthenium to gaseous and aerosol compounds.

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Section: Resultssupporting

confidence: 92%

Effect of nitrogen compounds on transport of ruthenium through the RCS

Kajan

Kärkelä

Auvinen

et al. 2017

J Radioanal Nucl Chem

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“…It was concluded that additional data are required in order to make a reliable assessment of the ruthenium outside releases in case of severe accident. Since this literature survey in 1986, many works were performed on this topic − to fill the gap in the prediction of ruthenium behavior. Ruthenium is usually considered as a low volatile fission product, with less than 5% releases, but in some conditions involving ruthenium oxides formation, as shown during the VERCORS HT2 tests dealing with the fission product release from UO 2 fuel with a moderate burn-up [48 (GWd/tU)], in pure steam, the ruthenium released amounted to 60% of the fuel inventory and a relevant part (12%) was transported as the oxide form and not deposited in the experimental line, even at quite a low temperature (150 °C).…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Properties of Gaseous Ruthenium Species

et al. 2015

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The review of thermodynamic data of ruthenium oxides reveals large uncertainties in some of the standard enthalpies of formation, motivating the use of high-level relativistic correlated quantum chemical methods to reduce the level of discrepancies. The reaction energies leading to the formation of ruthenium oxides RuO, RuO2, RuO3, and RuO4 have been calculated for a series of reactions. The combination of different quantum chemical methods has been investigated [DFT, CASSCF, MRCI, CASPT2, CCSD(T)] in order to predict the geometrical parameters, the energetics including electronic correlation and spin-orbit coupling. The most suitable method for ruthenium compounds is the use of TPSSh-5%HF for geometry optimization, followed by CCSD(T) with complete basis set (CBS) extrapolations for the calculation of the total electronic energies. SO-CASSCF seems to be accurate enough to estimate spin-orbit coupling contributions to the ground-state electronic energies. This methodology yields very accurate standard enthalpies of formations of all species, which are either in excellent agreement with the most reliable experimental data or provide an improved estimate for the others. These new data will be implemented in the thermodynamical databases that are used by the ASTEC code (accident source term evaluation code) to build models of ruthenium chemistry behavior in severe nuclear accident conditions. The paper also discusses the nature of the chemical bonds both from molecular orbital and topological view points.

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“…Through a series of ensuing reactions, the predominant carbon-bearing products (observed in the infrared) are found to be methanol and formaldehyde. 7,32,33 Other gases including CO 2 , H 2 O, and CO are also detected at lower mixing ratios, though whether these species develop as a direct result of CH 3 I photolysis is not immediately clear and will be part of a future study. In this paper, a data set was used in which the initial mixing ratio of the parent CH 3 I was ∼200 ppm.…”

Section: Methodsmentioning

confidence: 99%

An Interactive Spectral Analysis Tool for Chemical Identification and Quantification of Gas-Phase Species in Complex Spectra

et al. 2023

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A spectral analysis tool has been developed to interactively identify and quantify individual gas-phase species from complex infrared absorbance spectra obtained from laboratory or field data. The SpecQuant program has an intuitive graphical interface that accommodates both reference and experimental data with varying resolution and instrumental lineshape, as well as algorithms to readily align the wavenumber axis of a sample spectrum with the raster of a reference spectrum. Using a classical least squares model in conjunction with reference spectra such as those from the Pacific Northwest National Laboratory (PNNL) gas-phase infrared database or simulated spectra derived from the HITRAN line-by-line database, the mixing ratio of each identified species is determined along with its associated estimation error. After correcting the wavelength and intensity of the field data, SpecQuant displays the calculated mixing ratio versus the experimental data for each analyte along with the residual spectrum with any or all analyte fits subtracted for visual inspection of the fit and residuals. The software performance for multianalyte quantification was demonstrated using moderate resolution (0.5 cm–1) infrared spectra that were collected during the time-resolved infrared photolysis of methyl iodide.

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Deposition of RuO4 on various surfaces in a nuclear reactor containment

Cited by 18 publications

References 19 publications

Effect of nitrogen compounds on transport of ruthenium through the RCS

Effect of nitrogen compounds on transport of ruthenium through the RCS

Thermodynamic Properties of Gaseous Ruthenium Species

An Interactive Spectral Analysis Tool for Chemical Identification and Quantification of Gas-Phase Species in Complex Spectra

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