[en] Objectives of the project: In this review assignment, SKB's treatment of copper corrosion processes or mechanisms in SR-Site shall be reviewed both for the anticipated oxic and anoxic repository environments. The reviewer(s) shall consider if corrosion and corrosion mechanisms of the copper canisters in different possible evolutionary repository environments have been properly described. The objectives of this initial review phase in the area of copper corrosion is to achieve a broad coverage of SR-Site and its supporting references and in particular identify the need for complementary information and clarifications to be delivered by SKB. Summary by the authors: It is expected that the inflow of ground water to the deposition holes and tunnels in the Forsmark repository will be very slow. Thus, it might take some few hundred years up to thousand years before the deposition holes are filled with ground water and it might take 6000 years or more before the bentonite buffer is fully water saturated and pressurized. The copper canisters will therefore meet to two completely different environments: 1. An initial period of several hundreds of years when copper is exposed to gaseous corrosion. 2. And then to aqueous corrosion. From a corrosion point of view the first 1000 years are the most critical for the copper canister since pure, or phosphorus alloyed copper, is not designed to cope with corrosion at elevated temperatures. The outer copper surface temperature is expected to reach 100 deg C within some decades after closure of the repository and then slowly cool down to around 50 deg C after 1000 years. The gaseous corrosion is treated in SKB's safety assessment as being only dependent on oxygen gas and thus easily estimated by an oxygen mass-balance calculation. This simple model has no scientific support since several corrosive trace gases, such as sulphurous and nitrous compounds, operates together with water molecules (moisture) and the corrosion product consists mostly of oxides and hydroxides derived from water molecules. These trace gases are known to have an accelerating effect on copper corrosion. Any corrosion model describing the gaseous copper corrosion period must therefore be based on experimental data. The aqueous copper corrosion phase (without dissolved oxygen) is treated in SKB's safety assessment as being only dependent on sulphide ions and thus easily estimated by a sulphide mass-balance calculation. This is again a too simple model since copper reacts with water, especially when activated by chlorides in the ground water. A copper corrosion model must again be based on experimental data. Phosphorus copper is sensitive to stress corrosion cracking (SCC) in nitrous or sulphurous containing waters or in a combined environment, as will be the case in a repository, and cannot be ruled out as a potential problem. Embrittlement phenomena in copper caused by either hydrogen or sulphur cannot be ruled out as well. However SKB has disregarded SCC on vague basis in the safety assessment and copper embrittlement phenomena are not considered at all. Earth/stray current from the high voltage direct current Fenno-Scan cables to Finland are known to cause severe corrosion problem in bore holes in the Forsmark repository area. SKB has stated that there is no risk for earth current corrosion based on vague theoretical discussions. Experimental data are thus needed regarding all corrosion problems discussed here in order to reach a scientific basis for the copper corrosion assessment. It is not enough with simple oxygen- and sulphide mass-balance calculations for estimation the copper corrosion in a deep repository