2000-hour stress-corrosion cracking tests on 90-10 cupronickel in simulated Hanford groundwater

Self-loaded fracture mechanics specimens were tested in simulated groundwater at 150 degree C to evaluate the susceptibility of 90-10 cupronickel to environmentally enhanced cracking. The test duration was 2000 hours. Electron fractographic evidence indicated that no stress corrosion cracking occurred during the test. Compliance methods demonstrated that a substantial amount of crack extension did not occur during the 2000-hour exposure, but this method was insensitive to detecting crack growth increments less than 0.030 inch. Conventional macroscopic examination of fracture surfaces could not be used to determine if any crack extension occurred during the test because stains were observed beyond the original precrack. The stains were attributed to artifacts associated with postcracking procedures. 7 refs., 11 figs., 3 tabs