Thermal-hydrauhc analysis of cover gas region in steam generator of MONJU

Ito, Kei; Sakai, Takaaki; Yamaguchi, Akira; not registered

The upper region of steam generator is filled with argon cover gas. The cover gas is expected to constitute a complex natural circulation derived by heat exchange with cold feed water tubes, hot steam tubes, other structures and sodium surfaces. It is one of important issues to make clear the gas temperature distribution for a detail thermal-hydraulic evaluation in a steam generator. In this study, a cylindrical two-dimensional (2-D) code (MSG code) was applied to the whole region analysis of the Monju steam generator involving the cover gas region. In order to confirm the analysis accuracy, the 2-D results was compared with three-dimensional (3-D) results calculated by the FLUENT code, which has employed unstructured mesh for each tube, and both results were compared with measured temperature of the shell. In addition, a sensitivity of heat transfer coefficients to the shell temperature was been evaluated by the 3-D analysis. As a result, the cover gas temperature distribution by the 2-D analysis showed good agreement with the result by the 3-D analysis. In addition, it was confirmed that heat conductive coefficient has negligible effects on the shell temperature.