(MiHTEE 1) Materials in High Temperatures and Extreme Environments


The MiHTEE 1 Laboratory was established to experiment on materials in extreme environments and to test their limits. Tests such as high temperatures, corrosive salt exposures, and extreme pressure are all environments investigated in this lab. The MiHTEE 1 Lab has the capabilities to handle dangerous materials such as beryllium, uranium, and molten salts in a safe manner. These capabilities include: multizone heating thermal convection loops, pumped molten salt loop, several furnaces (inert and atmosphere), several gloveboxes, Hot Isostatic Sintering, and salt purification. This one-of-a-kind lab will push the limits of nuclear materials and provide valuable research for the nuclear industry.


Beryllium Capabilities

The MiHTEE lab has a joint glovebox equipped with HEPA filters in all inlets and outlets for beryllium work. One side is an air glovebox at negative pressure dedicated for beryllium preparation and contains all necessary tools a normal metallography lab would have including: a hot plate for mounting, high speed saw, auto polisher, gold coater, and a scale. The other glovebox is an argon environment with a furnace capable of operating from 0-900°C and a scale for experiments with solid beryllium compounds and liquid solutions such as FLiBe. A large antechamber connects the two gloveboxes so material can be prepped and experimented on without ever needing to leave the glovebox.


Chloride Purification

One of the key facilities in the MiHTEE lab is the Chloride Salt Purification Development (CSPD) facility. Much of the work in the MiHTEE lab relies on clean and consistent salt in order
to produce accurate and repeatable experimental results. The CSPD facility enables work with chloride salts by purifying commercially impure salt. Purities of < 600 ppm oxygen are consistently achieved with multiple different chloride salt mixtures. Salts are characterized via combustion analysis and ICP-MS to establish their purities. The CSPD facility has been regularly operated with a metallothermic purification process, but is compatible with other purification techniques like reactive gas and decomposing reagents. Most chloride salts can be processed in the CSPD facility, including some actinides.


Hot Isostatic Press (HIP)

The AIP6-30H is a research scale hot isostatic press (HIP). with it’s installed graphite furnace, it has a working zone 80mm in diameter and 125mm long that is rated for 2200C at 207 MPa. Our HIP can be used to make near-net shape parts with custom compositions for advanced manufacturing research.


Pumped Loop

Our pumped molten salt loop was designed by Copenhagen Atomics to help investigate how changing flow conditions and temperature gradients affect molten salt corrosion. The pumped loop has a salt-to-salt heat exchanger that generates up to a 100 °C change in temperature of
the salt along with a salt-to-air heat exchanger that generates a 25 °C change in temperature of the salt. With temperatures throughout the loop ranging from 700 °C to 575 °C and a flow rate of 2L/min out pumped molten loop will be capable of creating reactor-relevant conditions for
corrosion and deposition studies. The salt used in the loop is FLiNaK salt with additions to the salt currently being planned for future studies.


Thermal Convection Loops (TCLs)

Thermal convection loops (TCL) are used to more accurately model the thermal gradients and flow conditions found in a real molten salt reactor (MSR). A temperature gradient is created between parts of the loop, the hot and cold legs, which drives convective flow. Each TCL has eight independently controlled zones with ceramic fiber heaters that can reach up to 1260 C. Each heater has an accuracy of plus/minus 0.1 C. The system is attached to a vacuum system designed for fluoride (FLiNaK, FLiBe, UF4 salt mixtures, etc) and chloride (UCl salt mixtures, binary and ternary Cl salt mixtures) systems. The tubing is SS316H 3/4″ Schedule 40. Two loops gives the lab the capability to always have one loop on, allowing for high turnover and more experimental data.


Three Glovebox Inert Atmosphere

The three-glove glovebox contains an argon environment at atmospheric pressure with a water-cooled setup. This glovebox is mainly used to prepare air-sensitive materials, instruments, and equipment before various tests. There is also a small furnace, 0-1100°C, used for heat exposures that require an inert environment.