Neutron absorbing materials are critical for the safe storage of spent nuclear fuel (SNF). These materials must not only possess high neutron absorption capabilities but also demonstrate long-term stability and resistance to corrosion. In this review, we classify the different types of neutron absorbing materials and analyze their advantages and limitations. The primary corrosion mechanisms are summarized, including the micro-galvanic effects induced by secondary phases and Cr-depleted regions, and the irradiation-accelerated corrosion caused by SNF irradiation. Additionally, we also discuss the influence of H₃BO₃ and temperature on the corrosion behavior of neutron absorbing materials. Recent scientific studies to alleviate corrosion effects are highlighted, including ameliorating Cr-depleted regions, mitigating surface defects, optimizing interface structures, introducing crystalline defects, increasing alloy chemical complexity and adding corrosion inhibitors. This review aims to provide valuable insights and methodologies for enhancing the corrosion resistance of neutron absorbing materials, thereby supporting the safe storage of SNF.

Self-assembled monolayers of alkane thiolate and alkane selenolate have been proven to inhibit atmospheric corrosion, but upon prolonged exposure to the important constituents of indoor atmosphere, namely humidified air with formic acid, the protective layer eventually breaks, but the exact reason is not yet clear. In this paper, we report on an XPS study of co-adsorbed formic acid and hexane selenol on a Cu surface. Adsorption of hexane selenol at room temperature breaks the Se-C bond, leaving a monolayer of Se on the surface, whereas adsorption at 140 K leaves a layer of selenolate. Formic acid exposure to the selenolate-Cu surface leads to adsorbed formate on unprotected areas and absorption of formic acid within the alkane chain network. During heating, the formic acid desorbs and the Se-C bond breaks, but formic acid does not accelerate the Se-C scission, which occurs just below room temperature both with and without formic acid. Thus, formic acid alone does not affect the Se-C bond, but its presence may create disorder and open up the alkane carpet for other species. Selenol removes formate and oxide from the surface at room temperature. The Se-C bond breaks and the alkane chain reacts with surface oxygen to form carbon oxides and volatile hydrocarbons.

The corrosion behavior of B4C/6061Al in spent nuclear fuel (SNF) storage environments was investigated in H3BO3 solutions (0-10,000 ppm) at temperatures ranging from 20 degrees C to 90 degrees C by using experimental and computational approaches. The results reveal that dispersed B4C particles act as cathodes, accelerating the dissolution of the aluminum matrix rather than causing localized trench formation. In deionized water, a dual-layered protective corrosion product film forms, consisting of an inner gamma-AlOOH layer and an outer Al(OH)(3) layer. H3BO3 dissolves both the aluminum matrix and its corrosion products in the following order: Al(OH)(3) > gamma-AlOOH > aluminum matrix, with increasing effect at higher concentrations. Elevated temperatures enhance both the formation of corrosion products and the dissolution rate by H+. Overall, the results suggest that B4C/6061Al exhibits high corrosion resistance in deionized water (BWR conditions) but suffers significant degradation in H3BO3-containing pools (PWR conditions).

The effect of blue light on atmospheric corrosion of Cu and on the antimicrobial properties was explored upon exposure mimicking the condition of hygienic surface disinfection. The results show that blue light illumination enhanced the formation of Cu2O, resulting in a slightly increased corrosion resistance of Cu without pre-deposited NaCl, whereas the enhanced formation of Cu2O, CuCl and/or Cu(OH)3Cl on copper with pre-deposited NaCl caused concomitant corrosion product flaking and a reduced corrosion resistance. The blue light induced enhancement of Cu corrosion led to increased surface roughness and more pronounced integration of bacteria within the corrosion products.

First-principles calculations were employed to investigate the adsorption and diffusion energy of hydrogen (H) in the Ti/Ti3Al binary system, along with the evolution of the interfacial stability induced by the presence of H. The penetration energy barrier indicates that H can more easily penetrate the substrate through the Ti/Ti3Al interface. The formation energy of H increases with distance from the interface and the Ti/Ti3Al interface acts as a sink for trapping hydrogen interstitials. When all interstitial sites are completely occupied by H, the cleavage energy along the interface decreases from 1.935 to 1.094 J/m2, suggesting that H doping significantly reduces the strength of the Ti-Ti3Al (01–10) interface. When the area density of H-doping at the interface exceeds 0.37 atoms/Å2, the α-Ti lattice expands. Consistent with experimental observations, this triggers atomic migration and the generation of Ti-hydrides. Further analysis of the atomic structure and Bader charge transfers indicate that the interaction of Ti and H can alter the localized electronic structure of Al, leading to a weakened interface due to loss of interface bond strength. In summary, the theoretical calculations have provided new insights into possible hydrogen embrittlement (HE) mechanism in titanium alloys.

Surface films formed on pre-oxidized copper in anoxic simulated groundwater with sulphide were characterized by field emission gun scanning electron microscopy (FEG-SEM), Fourier transform infrared spectroscopy (FT-IR), open circuit potential (OCP) measurements, and via analysing the water chemistry and weight changes in the specimens. Additionally, films developed under identical conditions on pre-oxidized and ground copper specimens were characterized by glow discharge optical emission spectroscopy (GDOES). The results revealed that the sulphide content in the groundwater significantly influences the morphology, composition and thickness of the surface film. The build-up of Cu2S was evidenced at the sulphide contents of 32 mg/L and 320 mg/L. GDOES depth profiling revealed that sulphur and oxygen coexisted in the film all through its thickness, yet the surface was essentially rich in sulphur. The results from characterization are presented in detail in this paper and discussed from the perspective of capabilities of the used methods.

ToF-SIMS analysis of copper samples after exposures to simulated groundwater with and without sulfide addition was performed to investigate the penetration of corrosive species containing H, S, O, and Cl, into copper. Depth profiles show extent of penetration and 2D/3D images reveal local elemental distribution of the corrosive species at different depths inside copper. Pre-oxidation did not reduce the penetration while sulfide additional in groundwater and exposure at 60 degrees C significantly promoted the penetration. The extent of penetration of the corrosive species into copper demonstrates the need for risk assessment of complex corrosion forms such as sulfide-induced embrittlement and cracking.

The fracture mechanism of hydrogen charged Ti-6Al-4V has been investigated through a multianalytical approach. The difference in hydrogen solubility between 13 phase (high solubility) anda phase (low) governs the formation and growth pattern of titanium hydrides, and determine the fracture mode of Ti-6Al-4V. Depending on the hydrogen charging extent, the penetration of hydrogen and distribution of hydrides can be divided into three stages. In the initial stage hydrogen diffuses mainly into the 13 phase, as judged from its increase in Volta potential, and with no hydrides formed. Failure analysis after tensile tests exhibits plastic behavior and a fracture surface with mainly dimples. In the subsequent transition stage, hydrides are formed at the a/13 interfaces and along a grain boundaries. More initial cracks occur in the brittle hydrides and the fracture surface transforms from dimple to quasi-cleavage. In the final stage a layer of uniformly distributed hydride is produced on the surface and within the a phase. Supported by nanoindentation measurements, the plasticity of the charged sample diminishes with hydrogen charging time, and an intergranular-transgranular mixed fracture is observed. Overall, the study forms clear evidence that the distribution and cracks of hydrides influence the fracture mode of the Ti-6A-4V alloy.

A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate-resilient energy systems and infrastructures brings with it a long-term direction, so as a result the long-term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics.