Description

Corrosion of the copper canister under repository conditions.

SKB Number

SKB FEP Number

C11

Main Category

Main category for FEP

Internal process

System Component

System component to which the FEP applies

Cast iron insert and copper canister

Handling

Explanation of how the FEP is treated

Intact canister. Generally, corrosion is modelled based on mass balance and transport capacity considerations whereas reaction rates are disregarded. Sulphide in buffer and backfill modelled. Microbially generated sulphide in buffer pessimistically bounded by supply of nutrients for microbes. Initial oxygen in buffer: Pessimistically assumed that all oxygen corrodes copper neglecting oxygen consumption by buffer pyrite and rock. Initial oxygen in tunnel backfill: Consider consumption by rock and microbes. Potentially intruding oxygen: Integrated handling of rock, backfill and buffer conditions. Pitting (oxygen corrosion): Described as uneven general corrosion. Corrosion due to radiation: Negligible corrosion depths. Chloride assisted corrosion: Neglected if pH>4 and [Cl-]<2M. Corrosion effects on cold worked material neglected due to small consequences, if any. Corrosion by water modelled as "what-if-case" Failed canister. Not relevant.

References

Bibliographic references to obtain more information

SR-Site Fuel and canister process report, TR-10-46, Section(s) 1.10, 3.5.4