Thermal properties of Three Mile Island Unit 2 core debris and simulated debris

Nagase, Fumihisa; Uetsuka, Hiroshi

doi:10.1080/18811248.2011.636534

Cited by 12 publications

(3 citation statements)

References 11 publications

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“…In an accident situation as TMI-2, large amount of debris (among this part, 20 tons was liquefied) was found onto the lower part of the vessel. Simulated fuel debris samples having a similar chemical composition (in wt.%: 72.1 UO 2 , 20.5 ZrO 2 , 3.4 Fe 3 O 4 , 1.3 Cr 2 O 3 , 1.0 NiO, 1.7 Ag) to TMI-2 debris were fabricated in order to obtain data on melting temperature [94,95]. The melting temperature measured by thermal arrest technique was estimated to be about 2557 ± 50 • C, i.e., consistently with the Phebus FP tests.…”

Section: High Temperature Regime (Above 2200 • C)mentioning

confidence: 99%

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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Section: High Temperature Regime (Above 2200 • C)mentioning

confidence: 99%

Corium Experimental Thermodynamics: A Review and Some Perspectives

Barrachin

2021

Thermo

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“…In addition, it is important for the prediction of the debris states because the central part of the debris is expected to have been in a molten state for a long time because of its decay heat. The melting temperatures and phase states of the U-Zr-O system have been evaluated from experimental and thermodynamic viewpoints [1][2][3][4][5][6][7][8][9]. For the melting temperatures of the U-Pu-Zr-O system, however, only a thermodynamic calculation of the phase diagram of * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

The influences of Pu and Zr on the melting temperatures of the UO₂–PuO₂–ZrO₂pseudo-ternary system

Morimoto

Hirooka

Akashi

et al. 2015

Journal of Nuclear Science and Technology

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Specimens of (U, Pu, Zr)O 2 were prepared as simulated corium debris that were assumed like debris generated in the severe accident of the Fukushima Daiichi Nuclear Power Plant and their melting temperatures were measured by the thermal arrest technique in order to evaluate the influence of plutonium and zirconium content on the melting temperature of the corium debris. From the evaluation, it was found that the influence of zirconium on the melting temperatures of both (U, Pu, Zr)O 2 and (U, Zr)O 2 was similar and that the melting temperature of (U, Pu, Zr)O 2 had a local maximum value in the Pu-content between 0 and 20 mol%. The UO 2-PuO 2-ZrO 2 pseudo-ternary phase diagram at 2900 and 3000 K was evaluated from the present experimental results and previously reported results.

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“…A three-dimensional computer code developed for solid-liquid mixture flows was validated by a series of pure and mixed-melt freezing experiments using a low-melting-point alloy. In the analyses of relocation of molten core, thermal properties of molten and mixed core materials are required to be known and research on the thermal properties of molten core was carried out [5]. The specific heat capacity, thermal expansion coefficient, thermal diffusivity, and melting temperature were measured or estimated on the core debris samples of the Three Mile Island Unit 2 (TMI-2) reactor and simulated debris (SIMDEBRIS), which had chemical composition and porosity similar to the TMI-2 debris.…”

Section: Relocation Of Molten Corementioning

confidence: 99%

Review of thermal-hydraulic researches in severe accidents in light water reactors

Kataoka

2013

Journal of Nuclear Science and Technology

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The Tohoku Region Pacific Coast Earthquake and subsequent severe accident (SA) in Fukushima Daiichi Nuclear Power Station caused unprecedented disaster in Japan. Before this accident, considerable researches on SAs had been carried out in Japan. However, unfortunately, such researches could not prevent the accident due to the unexpected huge Tsunami. However, the researches on SAs become more and more important in order to make clear the causes of the accident in Fukushima and improve the safety of nuclear power plants in Japan. In view of this, review on researches on thermal hydraulics in SAs in light water reactors was carried out. Important thermal-hydraulic phenomena in SAs were identified. Research activities on each phenomenon were surveyed mainly based on the articles published in Journal of Nuclear Science and Technology of Atomic Energy Society of Japan.

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Thermal properties of Three Mile Island Unit 2 core debris and simulated debris

Cited by 12 publications

References 11 publications

Corium Experimental Thermodynamics: A Review and Some Perspectives

Corium Experimental Thermodynamics: A Review and Some Perspectives

The influences of Pu and Zr on the melting temperatures of the UO₂–PuO₂–ZrO₂pseudo-ternary system

Review of thermal-hydraulic researches in severe accidents in light water reactors

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Thermal properties of Three Mile Island Unit 2 core debris and simulated debris

Cited by 12 publications

References 11 publications

Corium Experimental Thermodynamics: A Review and Some Perspectives

Corium Experimental Thermodynamics: A Review and Some Perspectives

The influences of Pu and Zr on the melting temperatures of the UO2–PuO2–ZrO2pseudo-ternary system

Review of thermal-hydraulic researches in severe accidents in light water reactors

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Product

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The influences of Pu and Zr on the melting temperatures of the UO₂–PuO₂–ZrO₂pseudo-ternary system