Molten salt – metal interactions and their influence on thermomechanical properties of metals used in next generation molten salt energy systems

Materials are critical for delivering low-carbon electricity from renewable and low carbon power that includes Solar and nuclear thermal energies; technologies that underpin the UK’s commitment to reach net-zero greenhouse gas emissions by 2050. Next generation (Gen IV) concentrated solar power (CSP) plants and molten salts reactors (MSRs) will depend on high boiling point molten salts (MS) as coolants, heat transfer fluids and thermal energy storage at 750 degree Celsius to significantly increase UK’s low carbon electricity and contribute a projected rise of 27 percent in global solar thermal electricity by 2050. Alloys used in CSPs/MSRs are prone to degradation mechanisms linked to the electrochemical, irradiation (nuclear and solar thermal radiation) and mechanical stress effects across MS – metal interfaces. The potential for these mechanisms to occur in synergy also exists. This can can directly and/or indirectly influence alloys’ thermo-mechanical properties and resistance to MS induced degradation particularly in relation stress corrosion cracking (SCC) in MS systems.  

This project aims to investigate and characterise the electrochemical, irradiation (solar and nuclear thermal irradiation) and mechanical stress effects on the thermomechanical properties of metals during MS-metal interactions in Gen IV MSRs and CSPs, and at temperatures up to 800 degree Celsius. This study will deploy a combination of corrosion, and advance surface characterisation and fractographic techniques to understand and establish the links between the underpinning mechanisms of MS-metal interactions (chemical speciation and interfacial mobility, electrochemical and irradiation activities) and susceptibility for metals to fracture by SCC.