Effect of Axial Clearance on Loads During Cropping Simulated Nuclear Fuel Pins

Abstract

A new tool set was designed and manufactured to enable easy and accurate variation of the initial axial clearance between cutting blade and tube holder. Instrumentation was also provided for measuring longitudinal loads arising from lateral thrust and for monitoring any change in horizontal displacement during shearing. Both single and also small bundles of different simulated nuclear reactor fuel pins were cropped using this tool set and the effect of axial clearance on longitudinal and transverse loads was investigated. The ratio between the peak values of these loads was thus experimentally established, to help in the design of thrust bearings for actual cropping machines, once the required shearing loads are known. The variation in work done during cropping as a function of the axial clearance was also examined as well as the effects of bundle shape and size on tube cropping, although the latter was not exhaustively discussed.