To address these challenges, new operational paradigms for nuclear reactors are being explored. Among them, hydrogen production has emerged as a promising strategy to strengthen the competitiveness of nuclear energy. By coupling nuclear reactors with hydrogen production systems, it is possible to convert surplus electricity or thermal energy into a storable, versatile, and low-carbon energy carrier. This approach not only contributes to grid stability and sector coupling but also opens new revenue streams for nuclear operators, enabling higher capacity factors and improved economic performance.
Three technological pathways to nuclear Hydrogen
Currently, three main technological pathways are being developed for hydrogen production coupled with nuclear energy. The most mature is low-temperature electrolysis (LTE), which includes alkaline and proton exchange membrane (PEM) technologies. These systems are already commercially available and offer advantages such as operational flexibility and compatibility with existing nuclear plants. High-temperature steam electrolysis (HTSE), based on solid oxide electrolyzer cells (SOEC), operates at 650–1000 °C and achieves higher electrical efficiencies by leveraging both electricity and reactor heat. Although its technological maturity level is lower, HTSE is considered the most promising option in the long term for large-scale, low-carbon hydrogen production. Finally, thermochemical cycles, such as sulfur-iodine and copper-chlorine, offer high theoretical efficiencies but remain at early development stages due to challenges in materials and integration.
Technical, operational and economic feasibility of nuclear Hydrogen. R&D projects in Europe and USA
Westinghouse is actively involved in various R&D initiatives that assess the technical, operational, and economic feasibility of nuclear-coupled hydrogen production. In Europe, the NPHyCo project, funded by EURATOM, and with its Economic Work Package led by Westinghouse, evaluated the integration of hydrogen production with existing nuclear reactors. The project developed a conceptual design for a pilot plant and demonstrated that, within 5 to 10 years horizon, nuclear hydrogen could compete with other low-carbon production options.
In the United States, the Department of Energy is funding several Front-End Engineering Design (FEED) studies to assess the integration of HTSE systems into existing light-water reactors. These studies provide detailed engineering designs for both PWR and BWR reactors, evaluating energy extraction levels up to 500 MWe. Results confirm the technical feasibility of large-scale integration while identifying specific challenges related to thermal coupling, control systems, and infrastructure adaptation.
Operational feasibility has been addressed through the HydroGen Sim project, developed in collaboration with Idaho National Laboratory (INL). Using a full-scope glass-top simulator, the project tested normal and emergency scenarios, including a steam generator tube rupture. The simulations confirmed safe operation and highlighted the need for updated control room interfaces, new alarms, and rapid isolation systems to ensure safety in accident conditions.
Finally, on the economic side, analysis conducted under NPHyCo show that, although significant subsidies are currently required, future scenarios starting from 2030- with long-term operation conditions, CO₂ monetization, and technology maturation—could position nuclear hydrogen within a competitive market range, supported by incentives at level similar to those under the U.S. Inflation Reduction Act.
This article provides a comprehensive overview of the current state of hydrogen production coupled with nuclear energy, analysing its technological maturity, regulatory context, and deployment pathways. It concludes with a discussion of the remaining challenges and the actions needed to unlock the potential of nuclear hydrogen as a key enabler of the clean energy transition.
