EXAMINATION OF TITANIUM PULSE FEEDER DIAPHRAGM FAILURE

A Ti pulse feeder diaphragm failed by cracking after 450 hr service in the Homogeneous Reactor Test mock-up. The diaphragm, which was made of MST Grade III Ti, was vibrated at 78 cpm at 40 to 50 deg C. One side of the diaphragnn was exposed to demineralized H/sub 2/O and the other side was exposed to 10g U/l UO/ sub 2/SO/sub 4/ solution. The main corrosion product was TiO/sub 2/. (W.L.H.

BELLOWS FAILURE IN SOLIDS SEPARATION LOOP OF THE HRT MOCKUP

The failure of the valve bellows would appear to be due to a combination of stress corrosion nnd crevice corrosion. Stress corrosion occurred as evidenced by the transgranular branched cracking found in the bellows and in the base which was joined to the bellows. It seems probable that chlorides were present, which, along with the residual stresses present in the bellows assembly, created the necessary conddtions for stress corrosion to occur. Crevice corrosion occurred probably due to heavy deposits of solids at the base of the bellows, which created a condition of oxygen impoverishment. While the crater in the base may have been related to a galvanic effect created by the gold gasket, the contour of the crater would suggest that the cause of the crater was due more to crevice corrosion. (auth