Materials and Fuels Complex leading the way for America’s advanced nuclear energy fleet - East Idaho News
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Materials and Fuels Complex leading the way for America’s advanced nuclear energy fleet

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Check out this video on how the Materials and Fuels Complex powers the past, present and future of nuclear reactor development. | Image courtesy Idaho National Laboratory. Video Jordan Wood,

IDAHO FALLS — The iconic silver Experimental Breeder Reactor-II dome at the Materials and Fuels Complex (MFC) at Idaho National Laboratory is a bridge to both the past and future of nuclear energy.

“Building reactors, testing reactors, that’s the heart of what INL did for many, many years,” MFC Associate Lab Director Ron Crone said. “We’re getting back to that.”

The complex, located in the desert west of Idaho Falls, “is a testing center for advanced technologies associated with nuclear energy power systems and is the nexus for research on new reactor fuels and related materials,” according to an Idaho National Laboratory info sheet. It employs approximately 1,200 individuals and consists of 82 facilities, including 28 nuclear or radiological facilities and two reactors.

Today the 80-foot-tall dome is being retrofitted as a Demonstration and Operation of Microreactor Experiments (DOME) test bed for advanced nuclear energy reactors. A second Laboratory for Operations and Testing in the U.S. (LOTUS) test bed is also being constructed in the previous Zero Power Physics Reactor building at MFC.

MFC's DOME test bed
The DOME test bed is presently under construction at the Materials and Fuels Complex. | Jordan Wood,

“Not only do you have the ability to test the reactors here, now, you have all the ability to do the research, development and qualification of the fuels and materials so you can really get this advanced reactor fleet moving,” Crone said. took a tour of MFC to learn more about the impactful past, present and future of the complex on the development of nuclear energy around the world.

The past: Experimental Breeder Reactor-II

On Dec. 20, 1951, Experimental Breeder Reactor-I became the first nuclear reactor to generate electricity 50 miles west of Idaho Falls.

A second reactor, EBR-II, was built by Argonne National Laboratory afterwards at a location 23 miles away known as Argonne-West, now named the Materials and Fuels Complex.

According to INL, “it was built to demonstrate a complete sodium-cooled breeder reactor power plant. It was later modified to test other reactor designs and to test materials and fuels for fast reactors.”

EBR-II ran for three decades from 1964 to 1994. John Sackett was the director of EBR-II for 10 of those 30 years and was the manager for Argonne National Laboratory-West, before he retired in 2004.

“It was built as the prototype for what was anticipated to be a fleet of much larger reactors,” Sackett said. “That’s being realized now, interestingly enough, with the number of reactor projects such as the Bill Gates Natrium reactor proposed for Kemmerer, Wyoming, or another ARC-100 reactor proposed for New Brunswick, Canada.”

A relatively small reactor, EBR-II produced 2.5 MW thermal energy which was converted into about 20 MW electrical energy at an adjacent power plant, Sackett said, enough to power the complex with some to spare.

“The breeder reactor actually produces fuel as it consumes fuel,” Sackett said. “So it is very efficient in using the available energy in the supply of uranium – up to 90% or more of the available energy – whereas the current generation of reactors use something on the order of 1% to 4% of the available energy.”

It also produced significantly less nuclear waste.

To this day, an adjacent building, the Fuel Cycle Facility, processes fuel from the reactor.

“You could take fuel that was spent, reprocess it, and then place it back in that reactor,” Crone said. “Once you use nuclear fuel in a reactor, it still has, in some cases, well over half of its ability – half of its uranium 235 has still not been fissioned. So if you’re willing to put the effort in to extract that out and build a new fuel, it’s called closing the fuel cycle.”

The significance of the research performed at EBR-II has transformed the nuclear energy industry, Sackett said.

“EBR-II I would say was probably the most successful test reactor ever in terms of the scope of things that were accomplished,” Sackett explained. “Probably the most important contribution was demonstration of the ability of reactor systems to protect themselves without safety systems activating.”

In 1986, the inherent safety demonstration tests were conducted – showing the reactor could safely experience “one of the worst case scenarios that can happen — loss of all power and failure of all safety systems to actuate,” according to Sackett.

EBR-II Control Room | Courtesy Idaho National Laboratory
The Experimental Breeder Reactor-II control room operators oversaw the reactor’s safe performance through historic tests during its 30 years of operation. | Courtesy Idaho National Laboratory

In front of a large audience of 60 international scientists, engineers and members of the press, the “reactor successfully shut itself down naturally,” Sackett said. “That means that the reactor will shut down because of the physics associated with the core, such as rather than forcing cooling with the pumps, it cools with natural convection flow or … the reactor will simply expand enough that it shuts itself down as the temperature heats up.”

One month after the successful test in the United States, the Chernobyl accident occurred.

“We gained a lot of attention, and I think set the stage for the modern, advanced reactor designs that are more inherently safe,” Sackett said.

The complex contained every facility necessary to fully develop and test the technology.

“What we had was a complete set of nuclear facilities, self-contained at a site that could explore all aspects of the technology,” Sackett said.

“… It was EBR-II, the power plant, it was the fuel cycle facility that recycled the fuel, it was the TREAT test reactor that tested the fuel…, it was the Zero Powered Physics Reactor that could test the physics of these reactors and expand the core sizes and design in a variety of ways, as well as a fuel manufacturing facility that was used to build the fuel for EBR-II and so forth.”

The research laid the groundwork both for modern microreactors such as Oklo and larger commercial reactors such as the Terrapower Natrium reactor funded by Bill Gates.

While EBR-II could have continued operations for another 40 years, Congress cut funding for the program in 1994, leading to the reactor’s decommissioning.

The present: Nuclear fuels and materials manufacturing and testing

Today, MFC is expanding on its mission with the construction of new facilities. Crone took through a major new building, the Sample Preparation Laboratory.

“It’s the first major research and development hot cell built in the U.S. in about 40 years,” Crone said.

Sample Preparation Laboratory | Courtesy Idaho National Laboratory
The Sample and Preparation Laboratory will allow engineers to examine materials postradiation. | Courtesy Idaho National Laboratory

The hot cell’s walls are four feet thick to provide shielding. Inside the cell, cameras and robotics will help employees manipulate irradiated materials and examine them after they’ve been run through a reactor.

“When you have a nuclear reactor running and it’s producing neutrons and ionizing radiation, it does change the structural properties of steel,” Crone said. “… Ultimately you’re trying to find out is the strength of that material the same as it was pre-irradiation or if things have changed, how much have they changed?”

The Sample Preparation Laboratory will be able to conduct tests to “prove the material is behaving like it needs to for the safety of the reactor,” he explained.

The lab will specialize in in-depth nuclear materials research.

“If somebody has got an idea of a reactor they want to build, and then they want to qualify the material, we’ll be able to do that testing here,” Crone said. “What you’re looking at is different types of reactors with different types of materials and different types of fuel. You’re going to have this as your test bed to bring those materials here, get the testing done, get them qualified and get them licensed so they can run in a reactor 50 to 100 years.”

Construction on the Sample Preparation Laboratory commenced in 2020 and is expected to be completed by October 2024.

Sample Preparation Laboratory hot cell | Courtesy Idaho National Laboratory
Construction on the newest hot cell in the United States is nearing completion inside of the Sample Preparation Laboratory. | Courtesy Idaho National Laboratory

“We do work on nuclear fuels, we make nuclear fuels, we test nuclear fuels, and we also work on nuclear materials, “ Crone said. “Along with the fuel systems in a reactor, you need containment systems, you need reactor vessels and cladding systems. This building will be dedicated with a series of hot cells plus hot labs upstairs that’ll be looking at standard materials testing but for nuclear applications.”

At the nearby Experimental Fuels Facility, engineers manufacture a variety of advanced nuclear fuels.

“Many of the advanced reactor designs that people are looking at for the future utilize metallic fuels as well,” Advanced Fuel Fabrication and Development Manager Patrick Hogan said. “This facility overall at MFC is one of a very few, small number of places that has the ability of handling these types of materials safely, let alone with the experience, the expertise and the equipment to manufacture what are specialty fuels.”

Since the Materials and Fuels Complex manufactures fuels, fuel rods, fuel plates and fuel salts, it can “irradiate and test those in the Transient Reactor Test Facility (TREAT) or in the Advanced Test Reactor,” Crone said.

After the testing, engineers rigorously examine the fuel or material.

“All those things combined help enable the United States (nuclear) fleet to be developed over the next 20, 50 or 100 years,” Crone said.

The future: National Reactor Innovation Center

Across from the Sample Preparation Library, the DOME test bed is under construction inside of the repurposed EBR-II containment dome.

The National Reactor Innovation Center (NRIC), based out of Idaho National Laboratory, will operate DOME and the LOTUS test beds at MFC as a place for privately built reactor models to be tested and operated safely prior to commercialization.

“What we’re set up to do here is demonstrate new advanced reactors,” Crone said. “We’re working on three of them right now. … We’re going to add what is essentially the secondary side of a nuclear plant. So you can bring any up to I think it’s ten megawatts thermal.”

Currently, INL is partnering with three corporations to test reactor designs in the DOME test bed — Westinghouse Electric Company, Radiant Nuclear and Ultra Safe Nuclear Corporation.

“You can bring your reactor in there, hook it up to that secondary side and operate it inside the DOME to demonstrate it,” Crone said. “… Once they run that reactor, they can test the fuels and materials in order to license that reactor and sell it in the United States and all throughout the world.”

Construction on the DOME test bed commenced in Oct. 2023 and is expected to be completed by 2025, with the first tests of commercial nuclear reactors rolling out in 2026.

Final DOME rendering | Courtesy Idaho National Laboratory
The final Demonstration and Operation of Microreactor Experiments test bed layout is shown in this Idaho National Laboratory rendering. | Courtesy Idaho National Laboratory

As a steel shell lined with concrete, the DOME will have the capacity to seal off and isolate the reactor testing space from the outside world.

“It provides a test bed for companies to come in so they don’t have to spend the capital in building a containment structure,” National Reactor Innovation Center Technical Program Manager Troy Burnett said. “The DOME is going to provide that confinement in case something didn’t go as expected,” protecting the public, workers and the environment.

DOME will test microreactors that produce less than 20 MW of power.

“This isn’t for your giant commercial reactors that you would see all over the country … that produce one gigawatt electric,” Reactor Project Engineering Manager Aaron Balsmeier explained.

The LOTUS test bed will be able to use “different kinds of nuclear materials than the DOME that require a higher level of security,” he said.

Moving into the future, a great deal of research is focused on the development of micro and small modular reactors (SMRs) that will make nuclear power less expensive and more portable.

“The concept of a modular reactor is one where you can build parts in a factory, and then assemble them on site, making it cheaper,” Sackett said. ”Also, the smaller reactors are more easily designed to … exhibit inherently safe response to upsets, so they don’t need the complicated safety systems that many of the larger reactors do.”

Currently, the United States is served by a fleet of 93 large nuclear power plants that produce 1/5th of the country’s electricity. More than half of the nation’s carbon free power is produced by nuclear energy, Crone said.

“When you look at the future, … you’re going to add more big reactors to that fleet, but you’re also going to add medium and small ones,” he said.

MFC is partnering on the development of two microreactors– Project Pele with the Department of Defense and MARVEL with the U.S. Department of Energy. It also has contracts with Southern Company, a large utility, and Bill Gate’s Terrapower in Washington state, Crone said.

“We’re working on a molten chloride reactor to go in the LOTUS test bed for (Terrapower),” he said.

As the electric grid has developed and demand for electricity has increased, the need for more versatile and less expensive power sources has soared.

“You’re looking at data centers now that are using maybe gigawatts of power,” Crone said. “You might have companies that say, ‘I don’t even want to be hooked up to the grid. I want my own power plant.’ They want that level of of robustness and reliability. So that’s where nuclear can come in. Or even if you look at remote communities, you know, in Alaska and northern Canada where any fuel you pick besides nuclear, you got to constantly refuel.”

As more and more coal plants shut down, small modular reactors could be deployed to replace their energy production.

“The amount of area a nuclear plant takes up compared to a coal plant, it’s probably about a tenth,” Crone said.

With increasing national and international support, the nuclear industry appears to be on the cusp of a nuclear renaissance.

At the American Nuclear Society conference on June 17 in Las Vegas, U.S. Secretary of Energy Jennifer Granholm announced on, “We are entering a new era of nuclear energy — our single largest source of carbon-free electricity. We plan to invest up to $900 million to accelerate nuclear deployment, add more small modular reactors and reach more Americans with clean energy.”

Through its research at the the Materials and Fuels Complex, Idaho National Laboratory is dedicated not only to advancing the projects on the cutting-edge of nuclear development, but it also makes a top priority of being a strong community player.

With its education initiatives, support as United Way of Idaho’s largest donor, employee contributions and service hours, Idaho National Laboratory plays a significant role in the surrounding region.

“As a laboratory, we view our responsibilities to the Department of Energy to deliver technology. We’re very serious about that,” Crone said. “But we’re also very, very serious about being a standing member of the community that can be counted on to help with education and help with the entire life cycle (of) what it takes here to be part of the East Idaho community.”

The 1,200 men and women at the Materials and Fuels Complex are a dedicated part of that team propelling nuclear energy into into the future.

“What I tell people is that nuclear power can save the world if we let it,” Balsmeier said. “There’s so many problems that can be solved with nuclear power and especially advanced nuclear power. So I think it’s crucial to our community and our country to show that these kinds of technologies can work and that they’re safe and effective.”

MFC entrance
The entrance to the Materials and Fuels Complex. | Jordan Wood,