Key issues of the next decades will be a growing energy demand, global warming from carbon dioxide gas, and a fossil fuel, oil and coal, deplation, and so on. With these circumstances in mind. intensive studies and discussions on the R&D of a hydrogen gas and a large electricity production using a HTGR, a typical clean enenrgy, are making steady progress worldwide. The production of spherical fuel kernels can be carried out by wet chemical process, a sol-gel process, based on a solidification of droplets. Sol-gel process has advantages in a high purity and a low processing temperature. To obtain a proper UO2 kernel, first the spherical droplets should be formed by a vibro-dropping of an initial feed solution. The simulted PVA solutions are prepared with a reagnet, such as Mowiol, Poval, and Aldrich type A and B products. And the simulated solution was made by a dissolutin of a reagent PVA with a pure water to 8~10 wt %. In this study, first we carried out a same size spherical droplets preparation with a vibrating nozzle system by using simulated PVA solutions. Thermal decomposition characteristics of these PVA reagents are analyzed with TG/DTA ananlysis, and a spherical droplets shape was observed by digital camera.