DISCUSSION

International Conference on Nuclear Fuel Performance

Session 8 : Water Reactors

Chairman Mr T. J. Heal

Technical Secretary Dr G.G. Butler

ADDITIONAL INFORMATION ON PAPER NO 65

Further work has indicated that the Gd 0 lowers the mechanical strength of the UO^ and favours intergranular fracture. At high concentrations (approximately 20% Gd^O ) cracks appear at grain boundaries and grain pull-out is noticed on sections. It would appear that at these compositions the grain boundaries are weak, too weak in fact to bear the stresses imposed on them during cooling from the sintering temperature. A homogeneous 30% O&^p^ specimen showed 12 um grains almost completely separated by cracks.