Corrosion Mechanisms in Nuclear Waste Container Systems

Long-term containment of high-level radioactive waste relies on engineered barriers, most commonly steel vessels clad with copper or alternative corrosion-resistant alloys. Corrosion processes evolve as repository environments transition from oxic to anoxic conditions, driven by residual oxygen, groundwater chemistry, radiolysis products and microbial activity. In the early oxic phase, rapid general and localised corrosion can occur at defects in the copper coating, often accelerated by galvanic coupling between steel and copper. As oxygen is consumed, anoxic aqueous corrosion dominates, with sulphide and chloride species promoting film formation, embrittlement and pitting. Radiation fields induce radiolysis of water and air, generating hydrogen, hydrogen peroxide and nitrogen oxides that interact with metal surfaces, enhancing hydrogen uptake and modifying passive films. Over geological timescales, stress corrosion cracking, creep and fatigue under repository stresses, together with microbial influences in bentonite or fractured rock, may further compromise container integrity. Predictive models integrate multiphysics simulations, probabilistic pitting statistics and surface-analytical insights to estimate corrosion allowances and lifetimes in the range of 10^5–10^6 years. Such interdisciplinary research underpins safety assessments, informs material selection and guides repository design worldwide.

Research from Nature Portfolio

Recent studies have shown that γ-radiation in aqueous environments markedly enhances hydrogen absorption by copper, with uptake rates several orders of magnitude greater than non-irradiated systems. Radiation exposure not only drives hydrogen ingress but also induces surface cavity formation, nanoparticle deposits and crystalline needle-like islands, altering the protective film morphology. These findings underscore the need to incorporate radiation-enhanced hydrogen embrittlement and surface degradation into long-term safety assessments of copper-based waste containers.

Corrosion Mechanisms in Nuclear Waste Container Systems publication trend

The graph below shows the total number of articles in corrosion mechanisms in nuclear waste container systems across all publications each year (not limited to Nature Index journals).

Technical terms

Anoxic corrosion: Corrosion occurring in oxygen-depleted aqueous environments, often dominated by sulphide and chloride interactions.

Galvanic coupling: Accelerated corrosion of a less noble metal when electrically connected to a more noble metal in an electrolyte.

Radiolysis: Decomposition of water or air by radiation, producing reactive species such as H₂, H₂O₂ and NOₓ.

Pitting corrosion: Localised attack leading to the formation of small cavities or pits on a metal surface.

Long-cell corrosion: A form of electrochemical corrosion in which spatial separation of anodic and cathodic regions drives metal dissolution over extended distances.

References

1. Penetration of corrosive species into copper exposed to simulated O2-free groundwater by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Corrosion Science (2023).
2. Coupled mixed-potential and thermal-hydraulics model for long-term corrosion of copper canisters in deep geological repository. npj Materials Degradation (2023).
3. An evaluation of corrosion processes affecting copper-coated nuclear waste containers in a deep geological repository. Progress in Materials Science (2021).
4. An overview of the Canadian corrosion program for the long-term management of nuclear waste. Corrosion Engineering Science and Technology The International Journal of Corrosion Processes and Corrosion Control (2017).
5. Gamma radiation induces hydrogen absorption by copper in water. Scientific Reports (2016).
6. Probabilistic model for pitting of copper canisters. Materials and Corrosion (2020).