Method of manufacturing nuclear fuel pellet consisting of duplex grains

摘要

PURPOSE: A method is provided to reduce a mechanical interaction between the sintered body and the coated pipe by permitting the internal crystal grain and the external crystal grain to have different sizes. CONSTITUTION: A method for manufacturing a nuclear fuel sintered body(1) comprises the steps of shaping a form by compressing nuclear fuel powder; heating the form under a reducing gas atmosphere at the temperature of 1400 to 1750 Deg.C for 0.1 minute to 10 hours; and sintering the resultant structure under an equivalent oxygen tension atmosphere where the ratio of carbon oxide and hydrogen ranges from 0.15 to 0.70, at the temperature of 1400 to 1750 Deg.C for 10 minutes to 15 hours, in such a manner that the crystal grain existing in an external area(2) of the sintered body has a size of 3 to 15 micron meters and the crystal grain existing in an internal area(3) of the sintered body has a size 1.5 to 8 times larger than the size of the crystal grain exiting in the external area.