Nuclear-assisted hydrogen production presents unique material science challenges due to the extreme conditions involved, including high temperatures, corrosive environments, and radiation exposure. The integration of nuclear energy with hydrogen generation methods, such as high-temperature electrolysis or thermochemical cycles, demands materials that can withstand these harsh conditions while maintaining efficiency and longevity. Key challenges include material degradation, corrosion, radiation damage, and the need for advanced catalysts. Recent advancements in coatings, alloys, and composites offer promising solutions to enhance the durability and performance of nuclear-hydrogen systems.

High-temperature electrolysis (HTE) is a leading method for nuclear hydrogen production, leveraging the thermal energy from nuclear reactors to improve electrolysis efficiency. However, the operating conditions—typically above 700°C—introduce significant material stresses. The electrolyzer components, particularly the solid oxide electrolysis cells (SOECs), face degradation due to thermal cycling, chemical instability, and interfacial reactions between layers. The oxygen electrode, often made of lanthanum strontium manganite (LSM) or lanthanum strontium cobalt ferrite (LSCF), suffers from delamination and chromium poisoning when exposed to impurities. The hydrogen electrode, commonly nickel-yttria-stabilized zirconia (Ni-YSZ), is prone to redox cycling damage and microstructural coarsening over time.

To mitigate these issues, researchers are developing advanced materials with improved stability. Doped ceramic materials, such as gadolinium-doped ceria (GDC) or scandia-stabilized zirconia (ScSZ), show enhanced ionic conductivity and resistance to reduction at high temperatures. Protective coatings, such as thin films of alumina or spinel oxides, are being applied to interconnect materials to prevent chromium migration. Additionally, alternative electrode materials like lanthanum strontium titanate (LST) or praseodymium nickelate (PNO) exhibit superior electrochemical performance and durability under prolonged operation.

Thermochemical water-splitting cycles, such as the sulfur-iodine (S-I) or copper-chlorine (Cu-Cl) cycles, also rely on nuclear heat but introduce aggressive chemical environments. The S-I cycle involves highly corrosive sulfuric acid and hydriodic acid at elevated temperatures, necessitating materials resistant to both acid attack and thermal stress. Traditional alloys like Hastelloy or Inconel show limited longevity under these conditions due to passive film breakdown and localized corrosion. Advanced ceramics, such as silicon carbide (SiC) or tantalum carbide (TaC), are being explored for their exceptional chemical inertness and thermal stability. Composite materials, including fiber-reinforced ceramics or refractory metal liners, offer additional mechanical strength and corrosion resistance.

Radiation resistance is another critical challenge in nuclear hydrogen production. Neutron irradiation can cause displacement damage, phase instability, and swelling in structural materials. For instance, stainless steels used in reactor components may undergo radiation-induced segregation or embrittlement, compromising their integrity. Oxide dispersion-strengthened (ODS) steels, which incorporate nanoscale oxide particles, demonstrate superior resistance to radiation damage and high-temperature creep. Similarly, advanced alloys like nickel-based superalloys or tungsten-rhenium composites are being evaluated for their ability to maintain mechanical properties under irradiation.

Catalysts play a pivotal role in nuclear-assisted hydrogen production, particularly in thermochemical cycles or hybrid processes. Radiation can degrade conventional catalysts, reducing their activity and selectivity. Research is focused on developing radiation-tolerant catalysts, such as platinum-group metals supported on refractory oxides like zirconia or ceria. These supports provide stability against radiation-induced defects and sintering. Nanostructured catalysts, including core-shell or layered architectures, are also being investigated for their enhanced durability and catalytic performance. For example, ruthenium nanoparticles encapsulated in carbon nanotubes exhibit remarkable resistance to radiation while maintaining high activity for hydrogen evolution reactions.

Material compatibility is a recurring issue in nuclear-hydrogen systems, where dissimilar materials must interact without adverse reactions. For instance, brazing or welding joints between ceramics and metals in electrolyzers can fail due to thermal expansion mismatches or interdiffusion. Innovative joining techniques, such as reactive air brazing or diffusion bonding, are being developed to create robust interfaces. Additionally, functionally graded materials (FGMs), which transition gradually from one material to another, help alleviate stress concentrations at material boundaries.

The development of sensors and monitoring systems for nuclear-hydrogen environments is another area of active research. Conventional sensors often fail under high radiation or corrosive conditions. Advanced materials like diamond-based electrodes or optical fiber sensors coated with radiation-resistant polymers enable real-time monitoring of hydrogen concentration, temperature, and pressure. These sensors are critical for ensuring safe and efficient operation of nuclear-hydrogen facilities.

In summary, nuclear-assisted hydrogen production demands materials capable of withstanding extreme thermal, chemical, and radiative conditions. Advances in high-temperature ceramics, radiation-resistant alloys, protective coatings, and nanostructured catalysts are addressing these challenges. Ongoing research focuses on optimizing material properties, improving interfacial stability, and developing robust monitoring systems. These innovations are essential for realizing the potential of nuclear hydrogen as a scalable and sustainable energy carrier. The continued progress in material science will play a decisive role in overcoming the technical barriers and enabling the widespread adoption of nuclear-hydrogen technologies.