The purpose of this study is to get a optimal design of a nitrogen coating device of U-Mo particles surface.

* To the development of nuclear-reactor''s nuclear fuel, nuclear fuel of research nuclear-reactor for the multipurpose should be available such as irradiation safety, reprocessing, and mass production. As an alternative for achieve these conditions, the nitrogen coation method was adopted to inhibit the formation of the reaction layer between U-Mo particles and Al matrix in U-Mo/Al dispersion fuel. Also, the nitrogen coation equipment was designed consider of the effective formation of the nitrogen coating layer. The initial design of the device, it was composed of a cylindrical metal chamber, rotation motor, cooling jacket, electric furnace of tube type, vacuum pump, and gas injection control device. The core of this device is cylindrical metal chamber. The cylindrical metal chamber is made of ZrO2 with thickness of about 5 mm. And, the inside diameter of the chamber is about 55 mm and length is 195 mm. As the experimental results, the thickness of nitrogen coating was about 250 ㎚ (set temp. of 900 ℃) and 500 ㎚ (set temp. of 1000 ℃) with an increase of temperature. Therefore, the thickness of nitrogen coating was increased with an increase of temperature. Also, crystal structure was similar to the U-Mo when increases the temperature and reaction time. The second design of the device, cylindrical metal chamber was modified. Modification has installed four rods inside the chamber. The purpose of rod installation is to increase the contact of the nitrogen and U-Mo, and increase the mixing ratio of U-Mo. As a result, the reaction time was reduced when made the same thickness of the coating layer at the U-Mo particles surface. In order to improve these functions, equipment is designed such as fluidized bed reactor and impeller type reactor. But, the fluidized bed reactor and impeller type reactor was did not enhance because their function is limited by various factors such as the material or structure of the equipment.