PURPOSE: To increase flow rate of coolant in the core center with high power, mitigate power peaking limit and obtain a fuel loading pattern with improved neutron economy.

CONSTITUTION: On the lower surface of lower nozzle 1 on a fuel assembly, a pressure loss control plate 3 is fixed with fixing screws 6 in the four corners detachably. By attaching the pressure loss control plates 3 to the fuel assemblies, water channel cross sctional area is reduced to increase the pressure loss. This fuel assembly with the pressure loss control plate 3 is arranged in the core periphery where power is low and heat removal is not a problem. By this, the coolant flow is increased in the fuel assembly in the core center where power is high to mitigate power peaking limit and a fuel loading pattern with improved neutron economy is obtained. As the pressure loss control plate is detachable, it can be removed when the assembly is used in the core center with high power in the next cycle.