Device for use in a fuel assembly of nuclear power plant, method for manufacturing a device and method for activating a material in a nuclear power plant

A method for activating a material in a nuclear power plant comprising the following steps:

• providing a device for use in a fuel assembly of a nuclear power plant,
• the device comprises at least one rod,
• each rod comprises a plurality of containers having a space being filled with material to be activated,
• the device further including a flow restrictor for a fuel assembly of a nuclear power plant,
• the flow restrictor comprising:
• a plurality of fingers adapted to extend respectively into a control rod guide tube of the fuel assembly,
• the at least one rod being connected to a finger of the flow restrictor,
• the containers being arranged subsequently in a direction of a longitudinal axis of the respective rod,
• wherein the containers are connected to each other at connecting portions with one or more screw connection,
• each rod having been pressed or squeezed
• to form a marking corresponding to the connecting portion
• and to disable loosening of the screw connection,
• wherein each marking is in a direction of the longitudinal axis of the rod, and
• wherein each marking identifies the end of the space in a container and/or the end of the container;
• the device including at its upper end a coupling piece,
• the coupling piece including a spring to fix the device within the fuel assembly;
• inserting
• the device into a fuel assembly and, during outage of the nuclear power plant, providing the fuel assembly into a nuclear core of the nuclear power plant,
• or
• inserting
• the device during outage of the nuclear power plant into a fuel assembly of the nuclear core;
• operating the nuclear power plant;
• and
• during outage of the nuclear power plant, removing the fuel assembly from the nuclear core of the nuclear power plant.