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MARVEL microreactor prototype

The MARVEL microreactor prototype in the Materials and Fuels Complex’s machine shop.

Photo courtesy of Idaho National Laboratory

Idaho National Laboratory (INL) recently built a full-scale, electrically heated prototype to support the U.S. Department of Energy’s new MARVEL microreactor project. The prototype is one of the largest components ever machined at the lab and will be used to help validate the project’s final microreactor design that could be operational within the next two years.

Delivering the Prototype

INL machinists successfully assembled the prototype, which is known as a primary coolant apparatus test (PCAT) for the MARVEL microreactor. The PCAT was built in just nine months and is made of several stainless-steel components, including four Stirling engines that will generate electricity through primary and intermediate coolant pumps. It stands 12 feet tall and weighs 2,000 pounds, making it one of the largest components ever built at the lab’s Materials and Fuels Complex fabrication shop.

INL prototype for MARVEL project

The PCAT will be powered by an external electrical power supply, instead of fission, and will be used to ensure the MARVEL design and dynamics performs as expected.

“We use modeling tools to help regulators have confidence in the reactor design, but we can’t model all aspects of the flow and heat dynamics,” said Yasir Arafat, the MARVEL technical and project lead. “A demonstration is necessary for us to be certain that the final reactor will perform to a high degree of reliability and confidence level.”

Once hardware tests and simulation results are confirmed, the MARVEL team will use modeling and simulation tools to verify and support the reactor’s safety case.

The MARVEL Project

MARVEL is a sodium-potassium cooled microreactor that will generate 100-kilowatts of power. The project is on track to be the world’s first contemporary microreactor to be built and demonstrated at INL’s Transient Reactor Test Facility.

MARVEL will be used to test microreactor applications, develop regulatory approval processes, evaluate systems for remote monitoring, and develop autonomous control technologies. It will also be used to explore and test microreactors capabilities for a wide variety of electrical applications, nonelectric applications such as water purification and low-grade heat production for district heating and greenhouse climate control. 

MARVEL is expected to be connected to the world’s first nuclear microgrid at INL by 2024 and available for external researchers soon after. The MARVEL project is funded through the DOE Microreactor Program.

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