Fuel oxidation and thermal conductivity model for operating defective fuel rods

Lewis, Brian J.; Szpunar, Barbara; Iglesias, F.C.

doi:10.1016/s0022-3115(02)01231-x

Cited by 27 publications

(45 citation statements)

References 23 publications

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“…Eq. 4 is subject to the boundary conditions: zero temperature gradient at the centerline of the pellet and the fixed temperature value at the surface of the pellet, assumed to be the same as used before [17]: 870 K. (Table 1a).…”

Section: Cmpse2017mentioning

confidence: 99%

Accident tolerant composite nuclear fuels

et al. 2017

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Abstract. Investigated accident tolerant nuclear fuels are fuels with enhanced thermal conductivity, which can withstand the loss of coolant for a longer time by allowing faster dissipation of heat, thus lowering the centerline temperature and preventing the melting of the fuel. Traditional nuclear fuels have a very low thermal conductivity and can be significantly enhanced if transformed into a composite with a very high thermal conductivity components. In this study, we analyze the thermal properties of various composites of mixed oxides and thoria fuels to improve thermal conductivity for the next generation safer nuclear reactors.

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Section: Cmpse2017mentioning

confidence: 99%

Accident tolerant composite nuclear fuels

et al. 2017

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“…In Figure 1, the commonly used [6,9] Blackburn (B) correlation [10] and the most accepted Lindemer and Besmann (LB) [11] correlation are compared against the correlation (Perron) used by…”

Section: Equilibrium Stoichiometry Deviationmentioning

confidence: 99%

“…Cox et al showed very good agreement between their model and the experimental data [1] for 1 atm pressure; however, in the work performed by Lewis et al (e.g. [6,9]) on oxidation of defected irradiated fuel at 100 atm pressure, an extra factor of 2-3 for the surface-tovolume ratio had to be introduced to get agreement with experimental fission-product releases. The need for this extra factor was interpreted as the effect of surface roughness and cracking of the fuel.…”

Section: Introductionmentioning

confidence: 99%

“…Several correlations have been developed to describe the reduction in thermal conductivity with increasing fuel stoichiometry deviation [5,6]. Reduction in the fuel thermal conductivity can cause a significant temperature increase in operating fuel elements.…”

Section: Introductionmentioning

confidence: 99%

“…In the previous simulations of fuel elements [6], the surface area of the base of the cylinder was not taken into account (because usually the elements are much longer than their diameter). However for an equiaxed cylinder, if analysed by the previous methodology, the geometrical surface-to-volume ratio is equal to 2/r (r is the radius of the cylinder), while the full surface-tovolume ratio is equal to 3/r.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of the models of urania fuel oxidation in steam-rich atmosphere

Szpunar

2012

Journal of Nuclear Science and Technology

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The urania fuel oxidation model for a steam-rich atmosphere developed by Cox et al. using the extensive experimental database has been subsequently used widely but with some inconsistencies in implementations. They are listed and evaluated in this work to help improve the existing models as well as for future model development. The comparison of the equilibrium stoichiometry deviation, calculated using various models, is also given. Small differences between the equilibrium constants used for steam dissociation are found. In one application, the original model for steam dissociation was rewritten in terms of component partial pressures for simplification. It is shown that the modified model differs from the original model by a multiplicative factor (1 7 p O 2 /P tot ). A more complex equation that preserves total pressure is derived. However, the effect on the calculated fuel oxidation is much smaller than the effect of the uncertainty of the equilibrium stoichiometry deviation. The discrepancies in stoichiometry deviations and the estimate of the surface area of a pellet may lead to a double underprediction of fuel oxidation rate.

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