Abstract: The invention relates to an arrangement for carrying out leak detection of a fuel assembly for a pressurized-water nuclear reactor. A substantially vertical hollow mast means open in both ends houses the fuel assembly to be examined. The fuel assembly is drawn to the inside of the mast means from its lower side. The part of the mast means housing the fuel assembly is lifted to a position in which the fuel assembly is provided near but below the water surface of water inside the nuclear reactor. Water is sucked from a position inside the mast means above the fuel assembly. A gas separating means separates gases present in water sucked from the inside of the mast means. The separated gas is analyzed in a gas analyzing means regarding its amount of gaseous fission products.

Abstract: During leak detection of fuel assemblies (10) for a boiling water nuclear reactor, water is sucked from an area (12) located above an outlet (11) for water from the fuel assembly and around a gripper (8) for a loading machine (1) for fuel assemblies, which gripper is secured to the fuel assembly above the outlet, while the fuel assembly is lifted in the water (6) in which the fuel assembly is immersed or while the fuel assembly, after having been lifted in the water, is maintained in its lifted position or relowered in the water and while maintaining a flow of the water through the fuel assembly and around the gripper. The sucked-off water is subjected to an analysis with respect to the presence of fission products which, during operation of the reactor, have been formed of the fuel in the fuel assembly.