A single-bubble model for sodium expulsion from a heated channel

Reactor safety research programs. Quarterly progress report, April 1--June 30, 1977

“…The h e a t f l u x between t h e l i q u i d sodium and a vapor bubble a t t h e l i q u i dvapor i n t e r f a c e f o r slug-annular flow i s a dominant parameter i n determining t h e i n i t i a l phase of bubble growth i n a r e a c t o r c o o l a n t channel under a c c i d e n t cond i t i o n s . A s o l u t i o n f o r t h i s h e a t f l u x h a s been o b t a i n e d by Cronenberg (1971). I n numerical a p p l i c a t i o n of t h e s o l u t i o n , however, complications are encountered and s i m p l i f y i n g assumptions are imposed (Dunn, 1974).…”

“…The solution for the heat flux at the surface (liquid-bubble interface) as obtained by Cronenberg (1971) using the Laplace transformation method is given by…”

THERMOHYDRODYNAMIC MODEL FOR MOLTEN UO$sub 2$--Na INTERACTION, PERTAINING TO FAST-REACTOR FUEL-FAILURE ACCIDENTS.

“…An approach similar to that developed here was used in the analysis of single-bubble expulsion from a heated channel. 57 The results of that analysis are briefly illustrated in Appendix B. …”

“…The following text is a summary of an article to appear in Nuclear Engineering and Design which presents the results of that work. 57 …”

Ejection Velocity and Residual Film during Initial Expulsion of Sodium in Direct Heated Channel

“…It has been indicated from the past experimental studies< 2 >< 4 >< 5 > that the film of liquid left on the channel wall during an expulsion is a significant characteristic of the process. Analytical models< 6 >< 7 > have demonstrated that this film is essential for sustaining the expulsion. In the most recent surveys< 8 >< 9 > of sodium boiling phenomena, a single bubble model has been developed for reproducing the expulsion of sodium from a reactor coolant channel due to the occurrence of channel blockage or following a loss of flow accident, taking into account the effects on the expulsion process brought by the power density and fuel pin heat capacity as well as by liquid superheat and the presence of the liquid film.…”