More than 750 gallons of reactor-grade sodium flow through METL, making it the “nation’s largest liquid metal test facility,” according to the DOE. METL may not hold that status for long, however. TerraPower, the sodium fast reactor developer with cost-shared funding under the Advanced Reactor Demonstration Program to build a grid-scale Natrium reactor, is constructing a sodium test and fill facility in Kemmerer, Wyo., which is set to hold 400,000 gallons of sodium.
Replacing the trap: A cold trap like the one just replaced in METL is an essential component of liquid metal reactor designs, used to filter out oxide impurities present in the sodium coolant. If not removed, impurities can cause accelerated corrosion of the systems and lower flow rates, degrading the reactor’s performance.
Argonne replaced the device to meet specifications for future METL experiments. Because the facility uses welded construction techniques that the DOE says are “consistent with the maintenance of any advanced liquid metal reactor,” the replacement project builds U.S. experience in working with and replacing sodium loop components.
The sodium in the cold trap was frozen before the cold trap was cut out of the system and a new one was welded onto the sodium piping in its place. After months of planning, the process took two weeks to complete. During the replacement, the rest of the test loop remained molten and in operation, according to the DOE.
“It’s exciting,” said Matthew Weathered, a principal nuclear engineer at Argonne. “The METL team is revitalizing and developing these key operations and maintenance techniques to ensure we are able to deploy U.S. sodium cooled reactors in the near future.”
More on METL: METL took shape in 2018 to help advance research on liquid metal technologies and test components for potential use in sodium fast reactors. The facility can reach an operating temperature of 650°C, matching typical sodium reactor temperatures.
Reactor developers working with Argonne’s team at METL include ARC Clean Energy, Oklo, and TerraPower. METL plans to expand its testing capabilities in 2026 with a fifth test vessel.
The cold trap replacement was funded through the DOE’s National Reactor Innovation Center (NRIC), which funds operations and maintenance activities at the METL facility. Argonne consulted with the French Alternative Energies and Atomic Energy Commission prior to performing the operation.
See for yourself: Watch a video introduction to METL and a description of a gripper test facility for sodium fast reactor refueling featuring Argonne nuclear engineer Teddy Kent.
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