Cured overcoat coated fuel particles and method for producing nuclear fuel body using the same

摘要

PURPOSE:To prevent a coating layer by coating a surface of a coated fuel particle with a hardened over-coating layer which consists of a hardened matrix material made of a thermosetting resin containing graphite powder. CONSTITUTION:A coated fuel particle 3 can be obtained by sticking, with a ethanol spraying, a powder material (a matrix material A) which consists of 80 weight percent of a graphite powder and 20 weight percent of a phenol resin, to a coated fuel particle 1 of 900mum in diameter which is made by coating and by pyrolysis vacuum deposition of ceramics containing a carbon and a silicon cabide or a zirconium carbide, to a uranium dioxide core, to a coating thickness of 75mum, and after completing an over-coating in this way, by heating the particle with a heating furnace at 170 deg.C to harden the phenol resin and to form an over coating layer 2. To the particle 3, the same powder material as the matrix material A is over-coated to a coating thickness of 300mum. These particles are filled in a die and pressed to obtain a formed body and then the body is heated up to 1,800 deg.C in a vacuum condition and is so kept for one hour to be sintered. Through these processes, a nuclear fuel body can be obtained.