Application of Vacuum Technology during Nuclear Fuel Fabrication, Inspection Characterization

摘要

Vacuum technology plays very important role during various stages of fabrication, inspection and characterization of U, Pu based nuclear fuels. Controlled vacuum is needed for melting & casting of U, Pu based alloys, picture framing of the fuel meat for plate type fuel fabrication, carbothermic reduction for synthesis of (U-Pu) mixed carbide powder, dewaxing of green ceramic fuel pellets, degassing of sintered pellets and encapsulation of fuel pellets inside clad tube. Application of vacuum technology is also important during inspection & characterization of fuel materials and fuel pins by way of XRF & XRD analysis, Mass spectrometer Helium leak detection etc. A novel method of low temperature sintering of UO_2 developed at BARC using controlled vacuum as sintering atmosphere has undergone successful irradiation testing in CIRUS. The paper describes various fuel fabrication flow sheets highlighting the stages where vacuum applications are needed.