Interfacial Instabilities and Their Relation to Recriticality in a Disrupted LMFBR Core

摘要

Considerations of molten fuel-slug acceleration indicate that the Taylor instability mechanism will cause fuel disintegration following a mild power burst in a disrupted subassembly. This observation is used to obtain a simple expression for the fuel-slug acceleration length over which fuel breakup occurs and to develop a simple criterion for the threshold fuel-pool size below which it is possible to bound the degree of energetics when arbitrary mild recriticality situations are postulated. The possibility of molten hexcan wall steel mixing with molten fuel (Kelvin-Helmholtz instability) in a disrupted subassembly is also discussed and tentatively ruled out on the basis of available experimental information. Finally, a simple analysis of transient steel vapor condensation on upper pool liquid sodium demonstrates that sodium re-entry into the core by rapid steel vapor depressurization is prevented by sodium evaporation. (ERA citation 08:005187)