Experimentaland numerical investigation of liquid metal boiling in fuel subassemblies under natural circulation conditions

Boiling of Na-K eutectic alloy (22% Na; 78% K) in parallel channels under the natural circulation condition has been investigated at the AR-1 facility of IPPE. Hydrodynamics and heat transfer data have been obtained at this facility for various experiment set-ups of both single and parallel sections. A thermohydraulic code system based on the subchannel analysis code SABENA-3D has been developed and used to simulate these experiments. Comparisons show that the code system can reproduce the boiling phenomena in the test section with sufficient accuracy, correctly predicting the heat transfer conditions prior to and during the boiling.