Some properties of UO2-SiO2 melts

Lungu, S.; Beleuta, I.L.

doi:10.1016/0022-3115(70)90024-3

Cited by 8 publications

(6 citation statements)

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“…Thus the phase diagram reported in refs. [5,6] suggested that the high concentration of Si-rich inclusions and a high temperature made it possible to form the eutectic phase. Am and Pu were locally concentrated in the Si-rich phase.…”

Section: Resultsmentioning

confidence: 99%

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Behavior of Si impurity in Np–Am–MOX fuel irradiated in the experimental fast reactor Joyo

Maeda

Sasaki

Kato

et al. 2009

Journal of Nuclear Materials

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Section: Resultsmentioning

confidence: 99%

“…A preliminary calculation showed the fuel centerline temperature was more than 2400°C. The phase diagram of UO 2 -SiO 2 has been reported [5,6]. The MOX and UO 2 have a similar melting point.…”

Section: Resultsmentioning

confidence: 99%

Behavior of Si impurity in Np–Am–MOX fuel irradiated in the experimental fast reactor Joyo

Maeda

Sasaki

Kato

et al. 2009

Journal of Nuclear Materials

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“…• when the CaO/(CaO + SiO 2 ) ratio is low (case of siliceous concrete), the thermodynamics of the corium-concrete mixtures mainly depends on the UO 2 -ZrO 2 -SiO 2 ternary phase diagram. At high temperature, this chemical system presents a tendency to immiscibility which results from the thermodynamic behaviours observed in the UO 2 -SiO 2 [145,146] and ZrO 2 -SiO 2 [147,148] systems in which immiscibility at the liquid state was also observed. In the UO 2 -SiO 2 system, the miscibility gap which is today rather well established (even if it is in contradiction with previous data published by [149] or rejected in [150]) is positioned by Lungu et al [145,146] at the monotectic temperature of 2090 • C between 29 and 70 wt.% UO 2 .…”

Section: Ex-vessel Corium Progressionmentioning

confidence: 92%

“…At high temperature, this chemical system presents a tendency to immiscibility which results from the thermodynamic behaviours observed in the UO 2 -SiO 2 [145,146] and ZrO 2 -SiO 2 [147,148] systems in which immiscibility at the liquid state was also observed. In the UO 2 -SiO 2 system, the miscibility gap which is today rather well established (even if it is in contradiction with previous data published by [149] or rejected in [150]) is positioned by Lungu et al [145,146] at the monotectic temperature of 2090 • C between 29 and 70 wt.% UO 2 . New experimental results have been produced within the Severe Accident NETwork (SARNET) of the European Commission [151] and within the ISTC CORPHAD Project [152], confirming the existence of the two-phase liquid region in this system.…”

Section: Ex-vessel Corium Progressionmentioning

confidence: 92%

Corium Experimental Thermodynamics: A Review and Some Perspectives

Barrachin

2021

Thermo

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More than 30 years ago a specialist meeting was held at Joint Research Center Ispra (Italy) from 15 to 17 January 1990 to review the current understanding of chemistry during severe accidents in light water reactors (LWR). Let us consider that, at the end of the 1980s, thermodynamics introduced in the severe accident codes was really poor. Only some equilibrium constants for a few simple reactions between stoichiometric compounds were used as well as some simple correlations giving estimates of solidus and liquidus temperatures. In the same time, the CALPHAD method was developed and was full of promise to approximate the thermodynamic properties of a complex thermochemical system by the way of a critical assessment of experimental data, a definition of a simple physical model and an optimisation procedure to define the values of the model parameters. It was evident that a nuclear thermodynamic database had to be developed with that new technique to obtain quite rapidly prominent progress in the knowledge of thermochemistry in the severe accident research area. Discussions focused on the important chemical phenomena that could occur across the wide range of conditions of a damaged nuclear plant. The most pressing need for improved chemical models is identified with condensed phase mixtures to model the corium progression. This paper reviews more than 30 years of experimental data production in the field of corium thermodynamics. This work has been conducted through multiple international programs (EURATOM, ISTC, OECD) as well as through more specific studies conducted at the national scale. This research has been capitalised in specific databases such as NUCLEA and TAF-ID, databases developed at IRSN and at CEA, respectively, and are now used in degradation models of the severe accident simulation codes. This research is presented in this paper. In the conclusion, we outline the research perspectives that need to be considered in order to address today’s and tomorrow’s issues.

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“…Such pellets were expected to reduce the release rate of FP gases because of a longer path for these gases to reach grain boundaries [4]. The phase diagram in the UO 2 -SiO 2 system has been studied by Lungu and Beleuta [5]. They found that a liquid phase appeared above 1973 K and the liquidus temperature decreased with increasing SiO 2 content.…”

Section: Introductionmentioning

confidence: 97%