Flow-Induced Vibration Tests of a Plate-Type Fuel Assembly and Hydraulic Lifting Tests for Absorber in a Secondary Shutdown System

In the present study, the flow-induced vibration tests of the standard plate-type fuel assembly was performed and hydraulic lift tests for absorber in the secondary shutdown system was also performed. Nine Al 6061 fuel plates, which have the same dimension and geometry with the actual fuel plate, were used and the vibration amplitude of the fuel plate was measured by installing the strain gages on the fuel plated. A single-phase water was used as a working fluid. A hydraulic lift performance tests for absorber in a narrow gap was evaluated by using stainless balls and a SS-304 cylinder. The flow-induced vibration characteristics of the simulated plate-type fuels were experimentally evaluated for the coolant gap velocity of 1∼12 m/s. The vibration amplitude of the fuel plate was slightly increased as the coolant gap velocity was increased. But, the vibration amplitude that could indicate the dynamic instability due to the flow-induced vibration was not observed in the whole velocity range of the tests. In addition, the vibration amplitude of the simply supported fuel plate was higher than the vibration amplitude of the roll swaged fuel plate. The maximum RMS vibration amplitude of the simply supported fuel plate was lower than 0.007 mm. It was turned out to be that the ball lifting method was nor proper, because the transient phenomena was occurred during the lifting tests. However, the present experimental results showed that hydraulic lifting a cylinder could be successfully realized to lift and grab a absorber in a secondary shutdown system