Development of a double-Wall-Tube steam generator; Evaluation of thermal hydraulic tests on high mass flow rate condition

not registered ; not registered; not registered; Yatabe, Toshio

The objectives of the 1MW test model of Double-Wall-Tube Steam Generator (DWT-SG) are to evaluate the thermal hydraulic performance and structural integrity such as heat transfer property, hydrodynamic instability property, DNB temperature fluctuation and capacity of leak detection for the elimination of the secondary sodium loop of FBR Plant. This report describes the heat transfer and hydrodynamic instability characteristic of DWT-SG on high water mass velocity (approximately 400900 kg/msec) condition by tube plugging. Main results are followings : [Heat Transfer Characteristic] Evaluation of the tests clarified the sodium and water/steam side heat transfer coefficient and DNB quality correlations. Under normal output condition, the tube plugging induced no buckling of the tubes caused by temperature difference and no disproportionate sodium temperature distribution. (1) Sodium side heat transfer coefficient remains almost unchanged after tube plugging. Graber-Rieger's equation is better to be applied to this reigion than the other equations. (2) DNB quality of high mass velocity is also same as that of low mass velocity, Kon'kov's equation used for Phenix SG can predict experimental results in 20% errors. (3) As for pre-heat region, Dittus-Boelter's equation can predict experimental results in 20% errors in high mass velocity. But the heat transfer coefficient of this equation is larger than the experimental data in low mass velocity. (4) The experimental heat transfer coefficient of nucleate boiling region has a wide range, therefore it is very difficult to derive an experimental equation. Jens-Lottes' and Thom's equations are in the order of exprimental resaluts. (5) The range of the experimental heat transfer coefficient of film boiling region is a little wide, Mod. Tong's equation is better to be applied to this reigion than the other equations. (6) As for super-heat region, Bishop's equation can predict experimental results in 20% errors ...