[en] The Korea Nuclear Fuel Co. requested the high frequency flow-induced vibration and pressure drop tests of top, mid, IFM, bottom grid candidates of HIPER and protective grid candidates of a commercial fuel. The following results were obtained for each test. 1) High frequency flow-induced vibration of HIPER spacer grids Measured maximum vibration amplitude of the HIPER mid grid was under 21 mm/s at lower region of the grid's center spring. The peak vibration amplitudes of the upper, IFM, and bottom grids were 5∼10 times less than that of the mid grid. Peak frequency associated with the peak amplitude have gradually increased with the flow velocity. This suggested that a high frequency vibration of grid was originated from the vortex shedding due to the thickness edge of grid strap. 2) Hydraulic vibration test of protective grids for a commercial fuel Peak vibration amplitudes of 16x16 type fuel protective grids were above 200 mm/s at the frontal direction of HyGrid 4. There might be a strong resonance near at the measurement point of the grid. Peak vibration amplitude of 17x17 type fuel were measured by 46.6 mm/s, 376.5 mm/s for the ACE7 and RFA protective grids in order. Peak frequency also had increasing trend with the bundle flow velocity. Measured pressure drops of 16x16 type fuel protective grids were comparatively higher than those of the reference fuel protective grids