沸騰二相流における管群の振動応答特性 : 第1報,2×2管群での管の振動挙動

抄録

Prediction of fuel rod vibration in BWRs is important for designing a new fuel assembly An experimental study was performed to obtain the rod vibration characteristics for a 2×2 rod bundle in parallel boiling two-phase flow Vibration characteristics of fuel rod assembly were obtained under various conditions, e.g., system pressures of 0.98∼7.16 MPa, flow rates of 430∼1990 kg/m²s, inlet subcools of 33∼125 kJ/kg and outlet qualities of 0∼25%. The main results obtained from the high-temperature and high-pressure tests are as follows. The characteristics of vibration direction and response magnitude of a fuel rod were found to be random, and the amplitude was reduced to 1/5∼1/10 when the system pressure was increased from 1 MPa to 7 MPa. The effect of boiling on the rod vibration obtained to reduce the rod vibration response because of an increase of damping effect due to boiling.