핵 연료봉 표면보호를 위한 수용성 건식 윤활제 개발

Abstract

Currently, in order to resist the scratching of the fuel rod surface while fabricating the fuel assemblyof the light-water nuclear reactor, we use a solution of nitrocellulose, an explosive material, as a dry lubricantalong with its solvent. However, the demand for developing safe and harmless aqueous alternative materials forenvironment-conservation and field-worker safety has increased. In this study, we demonstrate the preparationof a novel aqueous resin composite using a formulation of aqueous polymeric resin, alcoholic solvent, and water. Subsequently, we characterize this composite on the basis of hardness, adhesive property, and water solubilityusing plates similar to the fuel rod material. The insertion test of a fuel rod coated with the YS-3 compositeshows load values of 18.8-20.5 kg/cm2, which is comparable with 18.0-20.5 kg/cm2 of the nitrocellulose coatingagent. In addition, the depth and width of longitudinal scratches caused by the YS-3 composite test are 50%higher than those of the standard. We can develop a harmless and safe aqueous dry lubricant to replace the existingNC products through field testing of 264 pieces of fuel rods, after producing 350 kg of the YS-3 prototype. The scratch test for the rod surface showed that weight of chip of YS-3 prototype was smaller than that of NCbefore and after solvent treatment, indicating the properties of YS-3 prototype was comparable to the counterpart.