Development of evaluation method of thermal-hydraulic stability of once-through steam generator by enhanced TRAC-BF1

Nakatsuka, Toru  ; Liu, W.; Yoshida, Hiroyuki  ; Takase, Kazuyuki

To assess the stability of once-through steam generators in FBR, Japan Atomic Energy Agency has been developing a prediction method for thermal-hydraulic instability based on system analysis code TRAC-BF1. In the present paper, to simulate the primary coolant in steam generators, thermal property of sodium was incorporated to the code and the VESSEL component was improved to handle two different fluids of primary sodium and secondary water. These added functions were assessed with a simplified steam generator model calculation by altering primary coolant fluid as water and sodium. It was confirmed that heat transfer at steam generators was properly evaluated for the case that primary coolant is sodium as well as water.