[en] In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in spheroidal graphite cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister. Based on literature study oxygen free phosphorus containing copper (Cu OFP) can be susceptible to stress corrosion cracking in presence of water with acetate-ions. The work described in this report was launched to investigate the effect of acetate-ions (in the concentration range 1 mg/l to 100 mg/l) on susceptibility of CuOFP to stress corrosion cracking. Experiments conducted in anoxic highly saline and saline simulated groundwater included slow strain rate tests complemented by fractography and voltammetry. Tests were performed with both CuOFP base metal and EB-weld metal samples. The test temperature was 100 deg C and the pressure 14 MPa, simulating the pressure expected due to the sum of the hydrostatic pressure and the compacted bentonite swelling pressure in a KBS-3 type repository at a depth of about 500 m in crystalline bedrock. Additionally, Auger-spectroscopy studies were performed to investigate the possibility of phosphorus segregation onto grain boundaries or other interfaces. The elongation to fracture values in the slow strain rate tests were comparable to those in air and showed no dependence on the acetate-ion concentration. The fractography of the samples showed a dimple like appearance of the fracture surfaces in all cases. Both of these results indicate that neither CuOFP base metal nor the EB-weld metal is susceptible to SCC in the environments in question. The voltammetry results in highly saline groundwater further supported this conclusion. The Auger-spectroscopy results (at the resolution limit of about 0.1 at%) showed no evidence for phosphorus segregation in either CuOFP base metal or the EB-weld metal. (orig.)