Relocation of metallic constituents in core debris beds

Technical Report · Thu Sep 01 04:00:00 EDT 1988

OSTI ID:6877207

Dosanjh, S S

The MELPROG computer code is being developed to provide a mechanistic treatment of Light Water Reactor (LWR) accidents from accident initiation through vessel failure. This paper describes a two-dimensional (r-z) debris meltdown model that has been developed for use in the MELPROG code. Of interest in this study is melt progression in particle beds that can form in both the reactor core and the lower plenum during severe LWR accidents. The analysis includes mass conservation equations for each species. A two-dimensional (r-z) momentum equation accounts for melt relocation to both gravity and capillary forces; viscous drag is included by modifying Darcy's Law to account for undersaturated flow, and the wetting behavior of molten stainless steel in contact with UO/sub 2/ is modeled using the formulation suggested by Scheidegger. As solid melts in the center of the bed, the porosity increases; collapse of the bed is incorporated using a critical minimum solid volume fraction ..cap alpha../sub s,min/. The energy equation considers conduction and radiation heat transfer in the bed, and phase diagrams are used to model Fe-Zr and U-Zr-O interactions.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (USA). Div. of Systems Research; Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6877207
• Report Number(s): NUREG/CR-5109; SAND-88-0535; ON: TI89000080
• Country of Publication: United States
• Language: English

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