PVD manufacturing process for inner protective liners enabling advanced cladding compositions to reduce fuel-cladding chemical interactions, corrosion and permeation

The U.S. DOE is prioritizing investment in a wide range of near-term and mid-term nuclear technologies for reliable base power to support infrastructure. Sodium fast reactors (SFRs) and molten salt reactors (MSRs) are principle drivers due to their transformative potential in addressing energy security, decarbonization, and nuclear waste challenges—all while offering compelling economic and scalability prospects. SFRs and MSRs need linear coatings applied to the inner cladding surface where it interfaces with the nuclear fuel. For SFRs, the coating prevents or minimizes direct chemical reactions between the metallic fuel (e.g. U-10Zr), the cladding material (i.e. FCCI), and molten Na metal. These interactions can lead to the formation of brittle intermetallic compounds, which degrade cladding performance. Na, especially if it contains impurities like oxygen, can be extremely corrosive to cladding materials and the inner coating can serve as a barrier. For MSRs, corrosion resistance is paramount as the salts (e.g. FLiBe+UF4/ThF4) are highly corrosive at the high temperatures and irradiation. A liner on the inner surface acts as a protective layer against corrosion and maintaining chemical stability of the cladding material to not react with the molten salt or any fission products that might dissolve in the salt. Inhibiting tritium diffusion and permeation can also be accomplished with advanced liner materials for the specific reactor design. In this Phase I SBIR, Starfire Industries will de-risk a novel physical-vapor deposition (PVD) coating technique for the application of advanced thin-film coatings onto the inner surface of small-diameter nuclear fuel cladding for liner protection for protect against chemical interactions. Long-life stable coatings would extend the lifespan of fuel claddings, which are critical components in MSRs and SFRs. Stable coatings would mitigate risks of cladding failure, which in MSRs could lead to fuel salt leaks and in SFRs could cause sodium-fuel interactions—both costly safety incidents. Longer-lasting claddings could enable higher burnup rates—extracting more energy from the same fuel volume—since the cladding wouldn’t degrade as quickly under prolonged irradiation. If successful, long-life stable coatings could slash lifecycle costs by 10-20% ($100-300 million per reactor over 40-60 years), boost revenue by $10-20 million annually per unit, and position companies to dominate a growing niche.