US unveils ‘world’s first’ irradiated molten salt research facility for next-gen reactors
The National Reactor Innovation Center (NRIC) has officially unveiled its Molten Salt Thermophysical Examination Capability (MSTEC).
The state-of-the-art facility is scheduled to begin full operations in March 2026. It aims to provide a critical infrastructure bridge for the commercialization of next-generation molten salt reactors (MSRs).
“The establishment of MSTEC marks a major achievement in our quest to advance next-generation nuclear reactor technologies,” said Brad Tomer, director of NRIC.
“By offering the essential experimental infrastructure and expertise to industry, MSTEC will be pivotal in addressing our national energy objectives and propelling the future of nuclear power.”
Designed to fill existing gaps
Several MSR concepts are currently under development globally. However, a significant barrier to their deployment has been the need for precise data on fuel salt performance.
MSTEC is specifically designed to fill these gaps by delivering reliable, reproducible data essential for the design, licensing, and eventual operation of advanced reactors.
“MSTEC provides specialized equipment to measure how materials behave under different conditions, and flexible laboratory spaces for small-scale experiments,” explained the researchers in a press release.
The facility is a shielded argon glovebox engineered to handle both irradiated and nonirradiated actinide materials. It focuses on high-temperature fluids, such as fluoride and chloride salts, which serve as fuel, coolant, or both in advanced reactor designs.
“MSTEC will be among the world’s first facilities capable of examining irradiated molten salt, supporting molten salt reactor research and pyroprocessing spent nuclear fuel,” added NRIC.
“The hot cell’s argon atmosphere supports research with irradiated and nonirradiated chlorides, fluorides, beryllium and actinides including plutonium and other minor actinides.”
Suite of instruments for remote operations
MSTEC provides a suite of precision instruments modified for remote operation to handle hazardous samples. A rheometer is used to measure viscosity and fluid flow at temperatures up to 1,000°C (1,832°F).
The gas displacement pycnometer nondestructively determines the density of solids using argon or helium. For high-temperature liquids like molten salts, a custom densitometer utilizes the Archimedes principle to measure density.
The universal furnace serves as a multifunctional tool for salt synthesis, electrochemical measurements, and corrosion studies.
In addition to this, a simultaneous thermal analyzer measures weight loss and energy change at temperatures up to 1,650°C to develop phase diagrams and determine melting points. The differential scanning calorimeter provides high-precision measurements of heat capacity and sample purity.
Utility beyond reactor design
The facility’s location at Idaho National Laboratory allows users to leverage adjacent world-class infrastructure, including the Advanced Test Reactor for irradiating salts and the Analytical Research Laboratories for detailed isotopic analysis.
Beyond reactor design, MSTEC’s equipment supports fuel cycle research, material accountancy, and nuclear safeguard-related tracking.
“MSTEC will significantly advance fuel salt technologies for the Department of Energy, industry and academia,” concluded INL’s senior molten salt researcher, Toni Karlsson.
“It also offers a unique platform for training future actinide scientists and fuel cycle researchers.”