The particle size distribution of solidified melt debris from molten fuel-coolant interaction experiments

Fletcher, David F.

doi:10.1016/0029-5493(88)90252-x

Cited by 23 publications

(4 citation statements)

References 5 publications

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“…The distributions can be regarded as a straight line for small fragments and then tend to be an asymptote as the fragments approach a maximum size. This type of distribution is referred to as the upper limit lognormal distribution, which was confirmed by Fletcher 17) to be applicable to the oxide fuel fragmented by the FCIs between the molten oxide fuel and the coolant water observed in light water reactors (LWRs). As seen in Fig.…”

Section: Experimental Conditionsmentioning

confidence: 99%

Fragmentation Mechanisms of a Single Molten Copper Jet Penetrating a Sodium Pool—Transition from Thermal to Hydrodynamic Fragmentation in Instantaneous Contact Interface Temperatures below Its Freezing Point—

Nishimura

Sugiyama

Kinoshita

et al. 2010

Journal of Nuclear Science and Technology

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To clarify the fragmentation mechanism of a molten metallic fuel jet in a sodium pool under highejection-velocity conditions that correspond to the medium-and high-burnup conditions in the metallic fuel core of liquid-metal-cooled fast breeder reactors, a series of experiments with molten copper as a metallic fuel simulant and a sodium pool was carried out. Under low-ejection-velocity conditions in the range of an ambient Weber number ðWe a Þ < 200, the fragmentation of the molten copper jet depends on the initial superheating of the jet. The size of copper fragments decreases with increasing initial superheating. Under high-ejection-velocity conditions in the range of We a ! 200, the size of the fragments is confirmed to be almost independent of the initial superheating of the jet. Furthermore, the size of the fragments agrees well with that evaluated using the Rayleigh-Taylor instability model, in which the fragment size is assumed to be equal to half the fastest growing wavelength. This result is qualitatively consistent with the characteristics that the molten jet column with large inertia force owing to the high ejection velocity, which transports enthalpy downwards, can penetrate the decelerated leading edge and can directly come into contact with sodium successively.

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Section: Experimental Conditionsmentioning

confidence: 99%

Fragmentation Mechanisms of a Single Molten Copper Jet Penetrating a Sodium Pool—Transition from Thermal to Hydrodynamic Fragmentation in Instantaneous Contact Interface Temperatures below Its Freezing Point—

Nishimura

Sugiyama

Kinoshita

et al. 2010

Journal of Nuclear Science and Technology

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show abstract

“…This section contains the results of calculations performed assuming that a high temperature melt, which has the properties of a uranium dioxide/molybdenum melt used in steam explosion experiments (Fletcher 1988), and water are mixed prior to triggering. The geometry considered is a 3 m long tube closed at both ends.…”

Section: Results From Simulationsmentioning

confidence: 99%

“…This assumption has the effect of treating the thermal fragmentation process as one in which droplets are removed from the outside of the droplet as in boundary layer stripping. A typical value of Lf = 100#m was used (Fletcher 1988). The fragment size Lf is not determined by the fragmentation models currently employed and was specified by reference to experimental data.…”

Section: ~-~(Ampmt )+ ~'~'-~Z(acempmwmt )mentioning

confidence: 99%

Vapour explosions: multiphase detonations or deflagrations?

Fletcher

1994

Shock Waves

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This paper contains a discussion of the various modes of propagation which may occur when a hot melt transfers its energy explosively to a cold volatile liquid. In particular, the possibility of the existence of detonation-like and deflagration-like behaviour is discussed and two different melt droplet fragmentation models which may lead to these two types of behaviour are presented. The transient, multiphase flow code CULDESAC is used to perform calculations for the two different cases and the theoretical existence of the two modes of propagation is established. Using results from the calculations it is concluded that the shape of the predicted pressure pulse observed in experiments is closer to the detonation-like solution obtained here. However, it is noted that careful experimental comparison is needed before any firm conclusions can be drawn.

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“…It is true even for small particles arising behind the shock wave [68][69][70]. We assume also that thickness of steam layer at the particle surface is much greater than the radiation wavelength.…”

Section: Cooling and Solidification Of Corium Particlesmentioning

confidence: 98%

Steam explosion in nuclear reactors: Droplets of molten steel vs core melt droplets

Dombrovsky

2017

International Journal of Heat and Mass Transfer

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The particle size distribution of solidified melt debris from molten fuel-coolant interaction experiments

Cited by 23 publications

References 5 publications

Fragmentation Mechanisms of a Single Molten Copper Jet Penetrating a Sodium Pool—Transition from Thermal to Hydrodynamic Fragmentation in Instantaneous Contact Interface Temperatures below Its Freezing Point—

Fragmentation Mechanisms of a Single Molten Copper Jet Penetrating a Sodium Pool—Transition from Thermal to Hydrodynamic Fragmentation in Instantaneous Contact Interface Temperatures below Its Freezing Point—

Vapour explosions: multiphase detonations or deflagrations?

Steam explosion in nuclear reactors: Droplets of molten steel vs core melt droplets

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