In plate-type fuel assemblies, fuel plates divide the flow channels into narrow, separate water gaps, preventing the mixing of coolant between adjacent gaps. An uneven flow rate distribution can deteriorate heat transfer and reduce the reactor’s safety margin. Thus, it is essential to investigate the hydraulic characteristics of plate-type fuel assemblies. This study examines these characteristics through experiments and computational fluid dynamics (CFD) analysis. The findings show that CFD analysis agrees closely with experimental results regarding the pressure drop characteristics of plate-type fuel assemblies, with a relative error of less than 1% under the target operating condition. The primary cause of pressure drop losses is the plate bundle section. The inlet fixing bar in the assembly causes the minimum flow rate to occur in the water gap directly below it, while the maximum flow rate occurs diagonally below the inlet fixing bar. The inlet fixing bar’s diversion effect directly influences the uniformity of flow rates among the water gaps. Additionally, the minimum flow rate non-uniformity factor increases with the inlet flow rate. This indicates that as the inlet velocity increases, flow rates among the water gaps tend to become more evenly distributed. Furthermore, due to the structural characteristics of the plate-type fuel assembly, flow velocity in intact water gaps gradually decreases along the flow direction, whereas in non-intact water gaps, it gradually increases.