Molten Salts and Materials Testing

The National Solar Thermal Testing Facility is a leader in advanced molten salt testing, achieving world record temperatures of up to 750° Celsius.

The NSTTF boasts the world’s largest molten salt research and development test loop supporting both concentrating solar power and industrial processes. Currently, efforts are underway to restart this critical testing infrastructure, further solidifying NSTTF’s role in advancing high-temperature solar and nuclear technologies. MSTL enables testing of molten salt hardware at high-flow and high-pressure over a range of temperatures.

Current features and capabilities:

  • 3 Test Stands
  • 60% NaNO3 / 40% KNO3
  • Flow rate: 1.5 m3/min (400 gal/min)
  • Salt temperature range: 300 – 585 °C (572-1085°F)
  • Maximum salt pressure: 40 bar or 580 psi
  • Remove up to 1.4MW solar thermal input

MSTL directly supports the U.S. Department of Energy’s SunShot goals by working to develop thermal energy storage costs ≤$15/kWhth and allowing for greater collection efficiencies and higher-temperature operation for linear Fresnel and trough systems by using molten salt HTF. It also provides a means of performing accelerated lifetime testing on components and reducing the risk of the technology.

Many of the lessons learned at this facility will be directly applicable to molten salt systems operating in the SunShot temperature range ≥ 650°C.

Industrial-Scale Molten Salt Test Loop (MSTL) Re-Start Project

Private companies, including many small businesses and start-ups, are working to commercialize molten salt systems for concentrating solar power, nuclear energy and other high-temperature industrial process heat applications. For concentrating solar power, a number of Generation 2 CSP-based companies are interested in research and development and evaluation of high-level Test Readiness Level molten salt components at an industrial scale, which presently is not available at a non-commercial location. Some of these companies include Flowserve Corporation and Gosco Valves, who presently do not have test facilities to test their valves beyond a 2-inch, inside diameter scale. Nooter/Eriksen are also interested in evaluating larger cross-sectional flow effects within tubes, and evaluating varying operational modes within heat exchangers.

A MSTL re-start would allow commercial companies to assess complex engineering issues at a national laboratory that de-risks challenges for separate effects testing and analysis without shutting down a commercial facility. There also are a number of industrial companies involved in nuclear reactor technologies, which build off the Molten Salt Reactor Experiment that took place from 1965 to 1969 at Oak Ridge National Laboratory. These companies include Terrestrial Energy, Transatomic, Yellowstone Energy, FLiBe Energy, and Terrapower. However, to bridge the gap from design to implementation, plant components and subsystems need to be fully tested and validated before they can be licensed by a regulator.

Contact

Ken Armijo, principal investigator
kmarmij@sandia.gov