The advancement of sustainable, high-performance nuclear energy systems depends critically on resolving thermal-hydraulic challenges that are common to both advanced fission reactors and emerging fusion concepts. Despite fundamental differences in their physical principles and operational environments, both systems face demanding requirements for high heat flux removal, multiphase flow stability, coolant chemistry control, and structural integrity under intense thermal and neutron loads.

A key challenge lies in managing extreme heat fluxes and complex multiphase flows in environments characterized by high neutron irradiation and transient thermal loads. Traditional thermal-hydraulic models are often inadequate for these regimes. Recent advances in high-temperature coolants (e.g., liquid metals, molten salts), micro-structured heat exchangers, and data-driven modelling techniques (e.g., AI-enhanced CFD, reduced-order models) offer promising pathways to overcome these limitations. At the fission-fusion interface, these shared challenges present unique opportunities for cross-disciplinary innovation.

This Research Topic explores how breakthroughs in materials science, fluid dynamics, and both high- and low-fidelity simulations can accelerate fusion energy deployment and improve the safety and performance of next-generation fission systems. By highlighting these interdisciplinary breakthroughs, we aim to address the persistent thermal-hydraulic bottlenecks at the fission-fusion interface that currently restrict the scalability, efficiency, and safety of advanced nuclear technologies. This Research Topic will support the development of robust and predictive frameworks for thermal-hydraulic performance, ultimately encouraging the advancement of safer, more efficient, and more scalable nuclear energy solutions.

This Research Topic invites contributions that advance the understanding and application of thermal-hydraulic innovations at the fission–fusion interface. We welcome Original Research, Reviews/Mini-Reviews, and Perspectives that address the shared and unique thermal-hydraulic challenges in next-generation nuclear systems. Specific themes of interest include:
• High heat flux management in fusion blankets and fission fuel assemblies
• Multiphase flow dynamics under extreme thermal and radiation conditions
• Advanced coolant technologies (e.g., liquid metals, molten salts, gases, supercritical fluids)
• Coupled thermal-hydraulic and neutronic modelling approaches
• Materials and surface engineering for enhanced heat transfer and corrosion resistance
• Experimental methods and validation strategies for high-fidelity simulations
• AI and data-driven techniques for predictive thermal-hydraulic modelling
• Cross-cutting design strategies for hybrid fission-fusion systems.

Are you interested in contributing a manuscript to this Research Topic?

Thermal-Hydraulic Innovations at the Fission–Fusion Interface