Validation study of thermal-hydraulic analysis program "SPRAL" for fuel pin bundle of sodium-cooled fast reactor

Ohshima, Hiroyuki; Imai, Yasutomo*

A numerical simulation system is being developed at JNC in order to offer methodologies to clarify thermal-hydraulic phenomena in a fuel subassembly of sodium-cooled fast reactors under various operating conditions. This paper describes the validation study of SPIRAL that is one component code of the numerical simulation system and that plays the role to simulate detailed local flow and temperature fields in a wire-wrapped fuel pin bundle. Fundamental validity related to solving mass, momentum and energy conservation equations and applicability of turbulence models were confirmed by simulating several basic problems. As the typical examples, two kinds of simulations using mainly high Re number models, backward facing step flow and flow in 4-fuel-pin bundle in a rectangular duct, are selected and the characteristics of flow field prediction by the models as well as the validity of the component code are mentioned.