Materials chemistry and transport modeling for severe accident analyses in light-water reactors I: External cladding oxidation

Olander, D.R.

doi:10.1016/0029-5493(94)90113-9

Cited by 34 publications

(12 citation statements)

References 13 publications

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“…No effect of steam pressure was taken into account for zirconium since it is known to be irrelevant at temperatures above 1100°C . Steam velocity is also irrelevant for zirconium oxidation unless steam starvation conditions arise . The hypothesized pressure and velocity conditions for SiC are similar to actual experimental conditions in this study, and no extrapolation of the data beyond the experimentally observed results have been made.…”

Section: Discussionmentioning

confidence: 85%

Silicon Carbide Oxidation in Steam up to 2 MPa

et al. 2014

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Growth and microstructure of a protective or nonprotective SiO2 scale and the subsequent volatilization of scale formed on high‐purity chemical vapor deposited (CVD) SiC and nuclear‐grade SiC/SiC composites have been studied during high‐temperature 100% steam exposure. The environmental parameters of interest were temperature from 1200°C to 1700°C, pressure of 0.1 to 2 MPa and flow velocities of 0.23 to 145 cm/s. Scale microstructure was characterized via electron microscopy and X‐ray diffractometry. The Arrhenius dependence of the parabolic oxidation and linear volatilization rate constants were determined. The linear volatilization rate exhibited a strong dependence on steam partial pressure with a weaker dependence on flow velocity. At high steam pressures, the oxide scale developed substantial porosity, which significantly accelerated material recession. The dominant oxide phase for the conditions studied was cristobalite. The oxidation behavior of SiC/SiC composite was strongly dependent on the state of the surface, specifically whether steam could find easy entry into the material via surface‐exposed interface layers. For the case where these as‐machined interfaces were surface coated with matrix CVD SiC, composite recession was found to be essentially that of high‐purity CVD SiC.

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Section: Discussionmentioning

confidence: 85%

Silicon Carbide Oxidation in Steam up to 2 MPa

et al. 2014

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“…In the physical process of sheath oxidation [126], with the absorption of oxygen by the sheathing, the steam mole fraction in the gas at the surface of the sheath is smaller than that in the bulk gas, and the oxygen uptake rate by the solid depends on the water flux through the external gas phase-boundary layer on the sheathing surface such that: D 2 Oðbulk gasÞ ! D 2 Oðgas at surfaceÞ ð 9aÞ…”

Section: Oxidation Hydriding and Embrittlement Of The Zircaloy Sheathmentioning

confidence: 99%

“…This latter treatment also incorporates non-equilibrium boundary concentrations that improve the prediction of the oxide layer thickness. An ''integral diffusion technique" has been further developed as a compromise between the computationally simple yet physically oversimplified parabolic kinetic technique and the highly descriptive but analytically complex full diffusion theory treatment [126]. In this method, the exact concentration distribution of oxygen in the metal phase is replaced by an approximate distribution that fits the boundary and initial conditions.…”

Section: Oxidation Hydriding and Embrittlement Of The Zircaloy Sheathmentioning

confidence: 99%

Overview of high-temperature fuel behaviour with relevance to CANDU fuel

Lewis

Iglesias

Dickson

et al. 2009

Journal of Nuclear Materials

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“…(30) where = The polynomial function in Equation (30) has only one minimum for positive values of , and that occurs at , thereby satisfying Equation (29) 2 .…”

Section: Oxygen Transport and Dissolution Of Oxide Layermentioning

confidence: 99%

Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report

Siefken¹

1999

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Preliminary designs are described for models of hydrogen and oxygen uptake in fuel rod cladding during severe accidents. Calculation of the uptake involves the modeling of seven processes: (1) diffusion of oxygen from the bulk gas into the boundary layer at the external cladding surface, (2) diffusion from the boundary layer into the oxide layer, (3) diffusion from the inner surface of the oxide layer into the metallic part of the cladding, (4) uptake of hydrogen in the event that the cladding oxide layer is dissolved in a steam-starved region, (5) embrittlement of cladding due to hydrogen uptake, (6) cracking of cladding during quenching due to its embrittlement and (7) release of hydrogen from the cladding after cracking of the cladding. An integral diffusion method is described for calculating the diffusion processes in the cladding. Experimental results are presented that show a rapid uptake of hydrogen in the event of dissolution of the oxide layer and a rapid release of hydrogen in the event of cracking of the oxide layer. These experimental results are used as a basis for calculating the rate of hydrogen uptake and the rate of hydrogen release. The uptake of hydrogen is limited to the equilibrium solubility calculated by applying Sievert's law. The uptake of hydrogen is an exothermic reaction that accelerates the heatup of a fuel rod. An embrittlement criteria is described that accounts for hydrogen and oxygen concentration and the extent of oxidation. A design is described for implementing the models for hydrogen and oxygen uptake and cladding embrittlement into the programming framework of the SCDAP/RELAP5 code. A test matrix is described for assessing the impact of the proposed models on the calculated behavior of fuel rods in severe accident conditions. This report is a revision and reissue of the report entitled; "Preliminary Design Report for Modeling of Hydrogen Uptake in Fuel Rod Cladding During Severe Accidents." vi

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Materials chemistry and transport modeling for severe accident analyses in light-water reactors I: External cladding oxidation

Cited by 34 publications

References 13 publications

Silicon Carbide Oxidation in Steam up to 2 MPa

Silicon Carbide Oxidation in Steam up to 2 MPa

Overview of high-temperature fuel behaviour with relevance to CANDU fuel

Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report

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