SPRING FORCE MEASUREMENT DEVICE FOR FUEL BUNDLE SPACER

PROBLEM TO BE SOLVED: To provide a device and method for measuring a spring force of a spacer spring within a fuel bundle. SOLUTION: This spring force measurement device includes a pulling-out rod standard 24, an insertion tube 38, an extension tube 40, a cable 36 inserted through tubes 38, 40 and extending. The cable 36 connects the standard 24 to a load cell, while the load cell is connected to a winch 44 through the cable 36. The pulling-out rod standard 24 is disposed within a fuel bundle 18 below a spacer S with a spring having a spring force to be measured. By pulling out the standard 24 through a spacer cell C, the spring force is calculated according to a tensile force of the connection cable 36 measured at the time of pulling out the standard 24, a known friction coefficient between a protrusion of the spacer spring and the pulling-out rod standard 24, and a total weight of the cable 36 and the pulling-out rod standard 24. This measurement operation is sequentially repeated about the upward spacers S.