The Microbial Processes Affecting the Integrity of Copper Canister in Geological Repository of Nuclear Waste

The nuclear waste disposal concept in Finland is based on a multi-barrier system where the spent nuclear fuel is disposed of in deep crystalline bedrock in copper canisters surrounded by clay buffer. The copper canisters should have lifetimes exceeding 100 000 years to prevent the release of radioactive nuclides to the environment. In anoxic water such as the ground water at the disposal site the corrosion of copper should be extremely slow. However microbial activity on the surface or in the vicinity of the copper canister can enhance corrosion in many different ways e.g. changing the pH or redox potential excretion of corrosive metabolites direct or indirect reduction or oxidation of corrosion products and formation of biofilms that create corrosive microenvironmentsIn this study microbially influenced corrosion (MIC) of copper was studied using electrochemical methods weight loss measurements and molecular biology methods in laboratory environment. The experiment was conducted under anoxic conditions in water simulating the groundwater of disposal site. Inoculations of sulfate reducing bacteria (SRB) acetogenic bacteria or methanogenic archaea enriched from the disposal site were added to the experiments. A sterilized abiotic environment was used as a reference environment.

Product Number: 51319-13019-SG
Author: Pauliina Rajala
Publication Date: 2019