Operating vibration measurements of test fuel assembly in reactor thermo-hydraulic test condition

Abstract

The design verification of a newly-developed nuclear fuel assembly requires a long-term endurance test under thermo-hydraulic test condition simulating power reactor core. For this verification test, vibration of the test fuel assembly inside the simulated test core should be measured under high system temperature (over 200 °C), high system pressure (over 2.5 MPa) and fast moving coolant flow (over 5 m/s). To measure the vibration, we use specially fabricated accelerometers, various sealing techniques and conduit channel design for signal cable protection. The effects of the flow rate, coolant temperature, pre-sized support clearance on the test fuel vibration response and orbit motion were discussed. The measured data is used for fuel compatibility evaluation and a basis for endurance verification, as well as the validation tool for theoretical response prediction model.