FIG. 1 — Simplified ionic map of the molten salt: circles represent cationic species, diamonds anionic species, and the dashed ring marks an amphoteric compound able to act as either.
Overview
This project was conducted alongside the graduate-level 'Novel Nuclear Reactor Design'.
The largest challenge facing molten salt reactor design is corrosivity. The combination of high temperature and corrosivity of the fuel create a hostile environment for materials and sensors. Amphoteric compounds are a proposed solution to address this. They can act as either an acid or a base, and form barriers to protect the material surfaces.
FIG. 2 — Aiden inside the Nuclear Quantum Engineering building of the Korea Advanced Institute of Science and Technology.
Approach
- Reviewed candidate amphoteric compounds in proposed fuel salt designs with thermodynamic and literature data.
- Compared to alternative methods of mitigating corrosion in MSRs.
- Assessed corrosion coupons of candidate structural alloys exposed to the salt under changing redox conditions.
- Predicted drawbacks of using amphoteric compounds, including unpredictable complex chemistry and sludge formation.
Results
I identified candidate amphoteric compounds with support from literature, including TiCl2 in LiCl-KCl and Ti in Cl salt solution, and compared the viability of titanium in chloride versus fluoride salt solutions. I concluded that fluorides may be a superior, understudied alternative due to their lower volatility.
Why it matters
Molten Salt Reactors have many strong advantages over traditional nuclear reactors, but the extreme environment of the fuel itself proves to be the biggest hurdle to deployment. With the right choice in amphoteric compounds and structural materials, the fuel can be turned from a promising model, into a feasible reality.