Local sodium boiling in a partially blocked simulated LMFBR subassembly (THORS Bundle 3B)

摘要

Experimental data from local sodium boiling tests with and without argon gas injection have been analyzed. The experiments were conducted with a 19-rod simulated LMFBR subassembly having the six central flow channels (12% of flow area) blocked in the heated section of the bundle. The data analysis shows that, without gas injection, local boiling in the blockage wake does not radially propagate to the surrounding free stream during two quasi-steady-state boiling periods of 13 and 27 sec. However, in tests with argon gas void fractions of 0.001 and 0.004, there is some evidence that the local boiling zone did spread but did not encompass the entire bundle cross section. An idealized extrapolation to full-size LMFBR subassemblies shows that the results with the 19-rod bundle are conservative. Analysis of data from nonboiling tests with gas injection shows that for void fractions between 0.00009 and 0.00354, the maximum temperature increase in the blockage wake due to gas injection is 40/sup 0/C (70/sup 0/F).