On the melting and refreezing of porous media

Technical Report · Thu Oct 01 04:00:00 EDT 1987

OSTI ID:5625560

Dosanjh, S S

A model of melt formation and relocation in a one-dimensional core rubble bed is presented in this report. The analysis includes: mass conservation equations for the species of interest (UO/sub 2/ and ZrO/sub 2/); a momentum equation that represents a balance among drag, capillary and gravity forces; and an energy equation that incorporates the effects of convection by the melt, radiation and conduction through the bed, and the energy release associated with fission product decay. An equilibrium UO/sub 2/-ZrO/sub 2/ phase diagram is prescribed and radiative heat transfer through the bed is incorporated utilizing a temperature dependent thermal conductivity. A parametric study is conducted in which the height of the bed, the average particle diameter, the initial composition, the initial temperature profile, and aspects of the phase diagram are varied. Results from this study are then used to evaluate the DEBRIS module in the MELPROG computer code. Particular attention is given to the semiempirical melt relocation models in DEBRIS. Experiments needed both to validate the current rubble bed model and to help guide future theoretical work are discussed. Three areas of uncertainty are addressed: (1) chemical interactions; (2) flow models; and (3) collapsing of a highly porous bed. 40 refs., 25 figs., 7 tabs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5625560
• Report Number(s): NUREG/CR-5028; SAND-87-1976; ON: TI88004259
• Country of Publication: United States
• Language: English

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