In this study, first the ADU gel particle, an intermediate for final

kernel of a HTGR nuclear fuel, was prepared from sol-gel method using the broth solution which was made by mixing of the uranyl nitrate, poly vinyl alcohol and tetra-hydrofurfuryl alcohol. The prepared dried-ADU gel particles were converted to the

from thermal treatment with the 4%

atmosphere. The sizes of the spherical liquid droplets appeared

, and the harmony between the flow rate of the broth solution and the frequency and the amplitude of a vibrating system are important factors for the spherical ADU gel particles via the mono size spherical droplets. From the XRD and FT-IR analyses, the prepared ADU gel particles were judged to be a

form, and the most important factor during the thermal treatment of the dried-ADU gel particle must be avoided a rapidly heating rate in the range of

, and the heating rate should be kept below

.