Prevention of fuel rod ballooning in nuclear power plants

Abstract

Possible means of eliminating ballooning as a mode of failure of fuel rods due to overheating are described. Ballooning tends to block cooling passages and hence render energency cooling inoperative. Means proposed involve altering the shape of the yield locus so that the plastic strain increment vector lies in the axial rather than the circumferential direction of the fuel rod. Proposed changes in yield locus are accomplished by texturing of the zirconium cladding or by grooving or by wrapping the fuel rod.