Molten salt reactors: A new testing facility improves pump shaft seals

[Marlin]

Molten salt reactors: A new testing facility improves pump shaft seals

https://news.engin.umich.edu/2026/07/molten-salt-reactors-a-new-testing-facility-improves-pump-shaft-seals/

[Core Content]

Researchers at the University of Michigan successfully tested a circumferential graphite bushing seal for 2,300 hours under simulated molten salt reactor conditions. The experiment utilized a custom facility to evaluate seal performance, wear, and cover gas effectiveness while using FLiNaK salt to mimic the corrosive environment of advanced nuclear reactors.

Reliable pump seals are necessary to contain radioactive and toxic vapors within Generation IV reactors. By identifying that radial clearance and argon cover gas are primary factors in seal longevity, this data provides a technical foundation for engineers designing high-temperature systems. Such long-duration testing addresses engineering barriers for the commercial deployment of advanced reactor technologies.

A rare, long-duration experiment tested a circumferential graphite bushing seal under conditions representing a molten salt reactor for 2,300 hours.

Molten salt nuclear reactors may potentially generate energy more efficiently than conventional water-cooled reactors while producing less waste, but the reactors must safely contain the salt's hazardous byproducts. Experiments on a commercially available shaft seal under molten salt reactor conditions at University of Michigan Engineering showed that, after a 10-day wear-in period, the seal operated successfully for 2,300 hours with minimal corrosion or degradation.

Read the full article at news.engin.umich.edu:
https://news.engin.umich.edu/2026/07/molten-salt-reactors-a-new-testing-facility-improves-pump-shaft-seals/