Griffin in the loop: A digital multiphysics test bed for next-gen reactors. February 26, 2026 By cory hatch. As U.S. energy demand increases, advanced nuclear energy has emerged as an important option for 24-7 reliable electricity and heat generation. Nuclear engineers in national laboratories and private industry have developed dozens of nuclear reactor designs that could soon power remote communities, space exploration, mining operations, military bases and data centers. Other advanced reactors could provide high-temperature heat and electricity for communities and industry. But developers need a way to test the safety and performance of these advanced reactors before building expensive prototypes. Researchers at the Idaho National Laboratory and Argonne National Laboratory jointly developed the Griffin reactor physics modeling and simulation software to enable accurate predictions of reactor performance across various designs, fuels and materials under real-world conditions. "Griffin can simulate a lot of the processes that are happening in a real-world operating reactor," said Argonne principal nuclear engineer Changho Lee. "It's closer to a real-life scenario where high temperatures, pressures and neutron flux in the harsh environment of a reactor core are causing changes to fuels and reactor materials. It's cheaper and safer to run, allowing you to explore numerous scenarios." Griffin has played a crucial role in multiphysics modeling, simulation and core design of advanced nuclear reactors. Now, the 2025 R&D 100 Award winning software is a staple for researchers, industry and regulators. As a cornerstone of advanced reactor development, Griffin integrates easily into the broader modeling ecosystem, paving the way for interconnected analyses. A master modeling and simulation tool. The U.S. Department of Energy Office of Nuclear Energy's Nuclear Energy Advanced Modeling and Simulation Program envisioned a comprehensive tool kit to support the development of advanced reactors. The Griffin tool is a critical part of this mission because it serves as the fundamental reactor physics tool. Built on the award-winning Multiphysics Object Oriented Simulation Environment (MOOSE) platform, Griffin draws from decades of expertise in computer science and reactor physics code development from both INL and Argonne. Its architecture allows it to couple seamlessly with other MOOSE-based codes for thermal fluids, thermo-chemistry, thermo-mechanics and more. "Griffin provides the basic nuclear physics that everything else is built on, which makes it the most important component for nuclear reactor simulation," said INL radiation transport methods development researcher Josh Hanophy. "It is built with the ability to interact with other physics within the MOOSE framework or outside of that framework as well." A supercharged multiphysics powerhouse. To accurately model a nuclear reactor, simulations must reflect neutronics, thermal hydraulics, structural mechanics, materials behavior, fuel performance and more. Griffin meets this challenge with a comprehensive suite of capabilities. Central to this feat is the linear Boltzmann transport equation solver, which captures complex radiation behavior within the reactor core. Griffin's algorithms track changes in isotopes over time, helping predict how fuel will evolve and how the reactor will perform. To further improve accuracy, Griffin calculates neutron interaction probabilities using nuclear data and machine learning. This allows for precise modeling of fuel usage, fission product creation and reactor efficiency. Griffin can accelerate simulations and allow researchers to choose between fast, lower-fidelity models and slower, high-fidelity ones. Versatile modeling possibilities. Griffin's strength lies not only in its technical depth but also in its adaptability across reactor types, capturing the underlying physics behind a wide range of phenomena such as density changes, aging effects, dimensional variations and isotopic or chemical composition shifts. This flexibility allows Griffin to support the analysis of designs for pebble bed reactors, prismatic high-temperature reactors, molten-salt reactors, fast-sodium and lead-cooled reactors, microreactors and other experimental systems. "To simulate the overall behavior of a given nuclear plant, you need to simulate the fuel rods, the pellets in the fuel rod, the pressure vessel, the materials, the pumps, the structures and even what happens outside the reactor core itself, including the coolant system," said INL reactor physics senior researcher Yaqi Wang. By enabling researchers, industry and regulators to explore these complex interactions virtually, Griffin accelerates innovation while reducing the need for costly physical tests. "Running computer models validated by experiments is significantly more cost-effective than building a physical reactor," said former INL research and development scientist Javier Ortensi. Griffin for space exploration. Griffin's versatility even extends beyond Earth. The software has been used to help design nuclear systems for NASA, demonstrating its value in space and lunar applications. These systems include nuclear thermal propulsion (a nuclear-powered rocket), microreactors for fission surface power on the moon and Mars, and devices that provide heat and electricity for remote applications and spacecraft. For example, engineers used Griffin to model nuclear thermal propulsion for the Defense Advanced Research Projects Agency's Demonstration Rocket for Agile Cislunar Operation. This project demonstrated a coupled physics system for a nuclear rocket, which allows them to operate for years with a smaller volume of fuel. For NASA, this means spacecraft can carry more equipment and personnel, travel faster and farther, and reduce crew exposure to cosmic radiation. Another NASA project used Griffin alongside other MOOSE applications to model a semi-autonomous startup sequence for a nuclear rocket. INL computational scientist Jackson Harter explained that Griffin, as a groundbreaking multiphysics radiation transport code, integrates smoothly with other MOOSE physics codes. This integration enabled Harter to conduct uncertainty quantification and sensitivity analysis studies. Supporting regulatory applications. Griffin's precision and robustness position it as a valuable tool for regulatory review. The Nuclear Regulatory Commission (NRC) is implementing Executive Orders and ADVANCE Act requirements for licensing advanced reactors, which often differ significantly from the current light-water reactor fleet in design, fuel and coolant. Because Griffin can produce highly accurate results, it is an important addition to the NRC's modeling and simulation toolset for evaluating non-light-water reactor designs. The software can provide independent verification of industry-provided simulation predictions. With support from the Griffin team, NRC and national laboratory researchers have developed reference plant models that incorporate key aspects of advanced reactor technologies. The NRC is working with these teams to refine those models as new designs come under review. Looking forward. As computing power grows, Griffin is poised to deliver even more detailed and accurate multiphysics models. These simulations will offer deeper insights into reactor behavior, enhancing nuclear energy systems on Earth and beyond. For one emerging area of application, fusion energy, Griffin can support safety design by modeling neutron interactions in the breeding blanket, the part of a fusion reactor where neutrons interact with lithium to produce tritium fuel. This will be essential for future fusion technologies. Until then, the Griffin team looks to its library of validation cases, comparing simulation results against real-world measurements to strengthen the tool's predictions. "Griffin aims to revolutionize nuclear energy by combining advanced computational power with deep scientific understanding, leading the way to a safer, more efficient energy future," said Ortensi. About Idaho National Laboratory. Battelle Energy Alliance manages INL for the U.S. Department of Energy's Office of Nuclear Energy. INL is the nation's center for nuclear energy research and development, and also performs research in each of DOE's strategic goal areas: energy, national security, science and the environment. For more information, visit www.inl.gov. * March 3, 2026 For decades, light water reactors have used control rods to regulate the fission reaction that powers a nuclear plant. The... * February 19, 2026 (IDAHO FALLS, Idaho) - The National Reactor Innovation Center's Molten Salt Thermophysical Examination Capability is set to begin operation in... * February 19, 2026 One path to becoming a successful researcher is to find an under explored scientific niche and add knowledge where it... * February 17, 2026 Prometheus Grand Challenge aims to deploy commercial-scale nuclear reactors in years, not decades. IDAHO FALLS, Idaho - The Idaho National Laboratory...

INL unveils $15M molten salt testing capability for advanced reactors. February 19, 2026 7:38 PM ATOMIC CITY, Idaho - Idaho National Laboratory is unveiling a new way to test fuel technology for advanced nuclear reactors at the Materials and Fuels Complex, west of Idaho Falls. "This is a capability that doesn't exist anywhere else in the world," said National Reactor Innovation Center Program Manager Josh Gillespie. "When we look at all the different kinds of nuclear reactors that are out there in the world, molten salt reactors are the ones that we have known the least about." The new research capability for advanced reactors, known as the Molten Salt Thermophysical Examination Capability (MSTEC), has a price tag of $15 million and took approximately five years to design and construct. "It's a new capability we have here... to examine molten salts and to work with our commercial partners to help them drive forward the commercial nuclear industry," Gillespie said. "... Before we can go off and commercialize these [molten salt] reactors and obtain a lot of the great benefits that they provide, we need to go get a lot of data so we can do this safely, so we can go off and enable the technology." Part of the National Reactor Innovation Center, MSTEC is housed at the Fuel Conditioning Facility at the Materials and Fuels Complex. The MSTEC consists of a "state-of-the-art, shielded argon glove box for irradiated and nonirradiated materials, specifically high-temperature liquids such as fuel salts," according to an INL press release. "The primary operation, or the primary function, of a glove box is just to keep our researchers safe," explained MSTEC System Engineer Nathan Petersen. "The stuff that they work on is hazardous, and so we want to make sure that they can perform their research without any kind of ill effects happening to them." The glove box contains eight robotic arms. It is designed to research the characteristics of molten salts deployed in certain advanced reactors - measuring up to 1000 degrees Celsius, viscosity, melting temperature and heat transfer, according to MSTEC Research Leader Mikael Karlsson. Molten salt reactors can use special salt as a fuel, INL researchers said. "The technology is not as well explored as a traditional reactor, right. So to be able to deploy the new reactor types, we need to be able to collect good experimental data," Karlsson said. Idaho National Laboratory is collaborating with partners such as Oklo, Saltfoss Energy, and others to help develop the fuel cycle. Article Topic Follows: News

Old electronics piling up? Idaho Falls event offers free safe disposal. Published at 3:52 pm, February 19, 2026 IDAHO FALLS - Old computers, phones, televisions and batteries often clutter up homes and garages because people aren't sure how to dispose of them safely. Unlike ordinary household garbage, electronic devices should not be thrown away or sent to landfills because they contain materials that can harm the environment, groundwater and wildlife. Idaho Falls-based E Cyclers of Idaho is filling an important niche in the community by helping residents responsibly dispose of unwanted electronics safely. The company is partnering with Idaho National Laboratory to host the second annual "Keep Idaho Beautiful" campaign, a free community e-waste collection event. The event will take place Saturday, Feb. 21, from 11 a.m. to 4 p.m. at the Idaho Falls Public Library. "As part of last year's campaign, we hosted 11 monthly collection sites, including Idaho State University, the Idaho Falls Public Library and Ammon City Hall," said Susie Cluff, business director and marketing manager. "Through those events, we collected and recycled more than 46,000 pounds of electronic waste that otherwise could have ended up in landfills or waterways." "An additional 111,000 pounds was dropped off by the community at our shop and at our Idaho Falls transfer station trailer," she said. This year, in partnership with the INL, E Cyclers of Idaho will expand the campaign to include potentially bimonthly free community electronic waste drop-off and recycling events at the Rexburg transfer station, the College of Eastern Idaho, ISU, the Fort Hall transfer station, and the City of Idaho Falls Library. Why proper disposal matters. Electronic waste is one of the fastest-growing waste streams worldwide. Many devices contain hazardous substances - including mercury, lead and cadmium - that can contaminate soil and groundwater if sent to landfills. Recycling electronics also conserves valuable materials. Items such as smartphones and computers contain recoverable metals including gold, silver, cobalt, lithium, graphite and copper, which can be reused in new products and reduce reliance on imported resources. There are also privacy concerns. Old devices may still contain sensitive personal or business information. E Cyclers of Idaho offers certified secure data destruction, ensuring that information stored on hard drives and other media is permanently removed to help prevent identity theft. What items are accepted. The event will accept most small electronic devices, whether working or not, including: * Computers, monitors, televisions, cellphones, tablets and gaming systems * Toner cartridges, scanners, fax machines and UPS units * Electronic cigarettes and circuit boards * Batteries and networking equipment such as routers, modems and Wi-Fi boosters * Virtually anything that uses batteries or plugs into a wall outlet "Devices are disassembled into their parts and processed for use as raw materials in new products. Non-renewable materials such as lead, cadmium, mercury, lithium, manganese, nickel, and zinc can be recycled an infinite number of times and have real commercial value," Cluff explained. Glass, copper, plastics, metals, and precious metals are sent through further processing for eventual reuse. Depending on the type, plastic can be made into shipping pallets or e-wood for outdoor furniture or play equipment. Manufacturers can extract lithium from old phones and make old batteries into new batteries. Printer toner can be used as an additive in recycled road surfaces, and the ink can be reused as 100% recycled ink. Items not accepted at the event include light bulbs and large appliances that are difficult to carry, such as refrigerators, washers, dryers, ovens and treadmills. Those larger items - excluding light bulbs - can instead be dropped off at the company's warehouse at 1976 N. Yellowstone Highway in Idaho Falls, near Blast Off. The facility offers 24-hour drop-off bins, including a secure container for devices that contain personal data. About E Cyclers of Idaho. E Cyclers of Idaho was founded in 2008 by Mark Jeffs, whose passion for tinkering with computers and electronics led him to create a business focused on responsible recycling and customer service. After Jeffs passed away in the summer of 2021, the company remained in the family. His wife chose not to close the business and instead sold it to Jeffs' nephew, Dan Forbush, who had previously worked for him beginning in 2013. Today, the company provides a wide range of services, including electronic recycling, secure data destruction, equipment removal, IT buyback programs, computer repair and refurbishment, and the sale of refurbished electronics. "We feel that what we are doing is essential to our community. Many others have expressed the same sentiment," Cluff said. "We love getting our message out to help support the local community and ensure the public knows we are here. We are looking forward to bringing our services further into the mainstream."