Local boiling in rod bundles: a theoretical model
- ed.
From 4th international seminar on heat and mass transfer in liquid metals; Trojir, Yugoslavia (6 Sep 1971). See CONF-710942-. A theoretical model is formulated to describe the process of local sodium boiling in a rod bundle geometry. The model is based on the assumption of single bubble boiling at substantial incipientboiling superheat and considers the hydraulic characteristics of a fuel rod bundle. In the numerical calculation, the effects of liquid superheat and of the non-uniform temperature field in the disturbed region are investigated. The analytical results lead to the preliminary conclusion that, even at superheats as high as 150 deg C, individual vapor bubbles recondense completely within about 35 ndsec, that the fuel cladding inside the bubble is not overheated during this time, and that local boiling is unlikely to cause thermal hydraulic instability in the affected fuel assembly. Furthermore, it is shown that in case of considerable superheat the rapid volume change of individual vapor bubbles causes variations of the coolant flow rate at the sub-assembly outlet, which may be detected by means of an electromagnetic flowmeter. (auth)
- Research Organization:
- Kernforschungszentrum, Karlsruhe, Ger.
- NSA Number:
- NSA-29-000304
- OSTI ID:
- 4425973
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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