COMPUTATIONAL MODELING OF EBR-II INSTRUMENTED SUBASSEMBLY
Experimental Breeder Reactor (EBR-II) was a liquid-metal-
cooled fast reactor, extensively used for conducting
safety experiments. EBR-II was heavily instrumented to
measure sodium flows and temperatures at various locations
in the primary circuit including the temperature distribution inside the subassemblies (SA). Amongst several transient tests conducted in the reactor, shutdown heat removal test (SHRT-17) conducted in 1984 gave very important data on temperature distribution in the primary circuit and inside the SA during natural circulation decay heat removal operation. Out of the released data, measured temperatures inside an instrumented subassembly XX09 at various elevations are very important. XX09 was a 61-pin (59 fueled) SA with helically wound spacer wire over each pin. The XX09 SA is a representative of standard EBR-II fuel SA, specifically designed with a variety of instrumentation to provide data for benchmark validation purposes. The SA was instrumented with wire wrap thermocouples, flow meters (below the core) and thermocouples at the SA inlet and outlet. The cylindrical fuel pins with helically wound spacer wire makes the geometry complex and mesh generation a challenging task. The present study is to validate the thermal-hydraulic modeling of fuel SA carried out for Indian Fast Reactor. Towards this, the CFD mesh of the SA computational domain including spacer wire has been generated using specially developed software GRRID-Z. The thermal hydraulic analysis of the SA has been carried out using a general purpose CFD code STAR-CD . The steady state and transient boundary conditions viz., inlet
flow rate, power generated in the SA were supplied as part of the benchmark data . The results show a good agreement with the measured data.