Argonne shines with R&D 100 Awards in nuclear innovation

The nuclear industry is about to benefit from three groundbreaking projects the U.S. Department of Energy’s (DOE) Argonne National Laboratory recently earned at the 2025 R&D 100 Awards. These awards recognize creative designs and modeling tools that will help advance the deployment of advanced nuclear power systems.

The so-called ​“Oscars of Innovation” honor exceptional advances made in the past two years. These awards reaffirm Argonne’s commitment to transformative science and technology. They underscore its leadership in nuclear energy research, reactor design and regulatory support for innovative energy solutions.

A state-of-the-art physics modeling tool

At the forefront of these advances is Griffin. Griffin is a state-of-the-art nuclear reactor physics modeling tool. It was developed jointly by Argonne and DOE’s Idaho National Laboratory. Griffin simulates how nuclear reactors operate with high accuracy and flexibility.

By accurately predicting the movement of neutrons and gamma rays under different conditions, Griffin helps researchers understand advanced reactor designs. This capability is critical for ensuring that reactors are safe, efficient and cost-effective.

“Griffin can model a wide range of nuclear reactor types used or being developed worldwide,” explained Changho Lee, Argonne senior nuclear engineer, manager of the methods development group and a member of the development team. ​“Griffin helps industry, research laboratories, academia and government organizations develop advanced reactor prototypes.”

Griffin is built on the Multiphysics Object Oriented Simulation Environment platform. It can simulate the complex phenomena occurring in nuclear reactors by coupling with other physics tools. Multiphysics simulations with Griffin show how everything inside a reactor works.

“Power distribution within a reactor core is constantly evolving,” said Shikhar Kumar, principal nuclear engineer and Griffin team member. ​“If reactor conditions change, Griffin models these changes through multiphysics simulations that relate the varying physical phenomena together.”

“Griffin helps industry, research laboratories, academia and government organizations develop advanced reactor prototypes.” — Changho Lee, Argonne senior nuclear engineer

Griffin can model a variety of reactor types, including high-temperature reactors, molten-salt reactors, fast reactors and microreactors. This adaptability helps researchers explore and test a range of new designs.

Its accuracy is also useful for projects outside the traditional energy sector. For example, Griffin was used in NASA’s Demonstration Rocket for Agile Cislunar Operations project. This project aims to develop nuclear-powered rockets for travel between Earth and the Moon.

So far, the tool has been used by national laboratories, academia, industry and the U.S. Nuclear Regulatory Commission (NRC). Simulations, like those from Griffin, are also vital for the licensing process. They help the NRC evaluate the safety of new reactor designs. By replacing physical prototypes with virtual models, Griffin reduces the cost and time needed to bring new technologies to market.

Griffin, with its ability to model any reactor type and role in regulatory reviews, is a driving force in the future of nuclear energy.

The Griffin-Argonne development team includes Changho Lee, Hansol Park, Shikhar Kumar and Seoyoon Jeon. Its development was funded by the DOE Office of Nuclear Energy’s Advanced Modeling and Simulation program.

A breakthrough technology for compact nuclear reactors

In parallel, Argonne researchers developed a breakthrough solution to a critical challenge in some of the small, portable nuclear reactors, called microreactors. The breakthrough consists of an innovative material design to safely contain a high concentration of hydrogen at high temperatures in the reactor.

The project, ​“High Temperature Hydride Moderator Containment,” also earned an R&D 100 Award.

Hydrogen is vital in such nuclear systems. It acts as a moderator by slowing down neutrons to sustain fission, the reaction that splits atoms to release energy. However, hydrogen tends to escape its containment materials at high temperatures. This reduces reactor efficiency and operability.

Existing containment measures have struggled to balance durable performance with operability. Ceramic enclosures can crack under heat stress and enclosures with thick metal walls tend to absorb neutrons, decreasing reactor performance.

Argonne’s award-winning solution combined the best of both approaches. The Advanced Moderator Module (AMM) technology employs a ceramic-based multi-layer coating on a thin metal liner. The technology locks in hydrogen, even at temperatures greater than 600 degrees Celsius. Microreactors can run more efficiently and last longer with this moderator design.

“If reactor designs can operate at a higher temperature, that improves efficiency, and that means more electricity can be extracted out of the system.” — Yinbin Miao, Argonne principal materials scientist

“Hydrogen is a neutron booster,” said Nicolas Stauff, manager of Argonne’s nuclear applications and economics group and a member of the development team. ​“It makes the neutrons more efficient at fissioning with uranium. So, it is extremely important for those types of reactors to have a lot of hydrogen and to not lose it. The challenge is to ensure hydrogen remains contained at high temperatures like 700 to 800 degrees Celsius.”

The AMM technology opens the door to a new generation of small and portable units that can power remote communities, off-grid industrial sites, military bases or even space missions. It can use metal hydrides, such as yttrium hydride (YH₂), as moderators under higher temperature conditions to meet reactor performance requirements.

“If reactor designs can operate at a higher temperature, that improves efficiency, and that means more electricity can be extracted out of the system,” said Yinbin Miao, an Argonne principal materials scientist.

Sumit Bhattacharya, a materials scientist at Argonne, explained that designs that use AMM technology can also accommodate low-temperature-stable metal hydrides. These types of materials, such as zirconium hydride, can be used in microreactors and operate below 600 degrees Celsius.

Additionally, the technology’s flexible design makes it adaptable to different reactor setups, including heat-pipe, gas-cooled and molten salt systems.

The Argonne team, which includes Abdellatif Yacout, Sumit Bhattacharya, Yinbin Miao, Nicolas Stauff and Taek Kim, has already secured a patent for the hydrogen containment technique. Their research was funded by the DOE’s Office of Nuclear Energy’s Microreactor Program.

By solving the hydrogen containment challenge, the AMM design offers a practical solution and represents a significant step forward in nuclear reactor design. With its potential to enable compact, long-life microreactors, this innovation could play a key role in expanding the use of nuclear energy in remote locations and beyond the grid applications.

A simulation toolkit for next-generation nuclear design

The third award-winning project is OpenMC, led by Argonne and the Massachusetts Institute of Technology (MIT). It is free software that helps scientists model how neutrons and photons move inside and interact with materials in nuclear reactors. It can run on anything from a laptop to the world’s largest supercomputers. OpenMC can automatically test different reactor designs, use machine learning to improve results and show data in real time.

“[OpenMC] can predict, for example, how quickly nuclear fuel will be consumed or how much damage radiation will cause to reactor materials.” — Paul Romano, computational scientist

Argonne’s development team includes Paul Romano, Patrick Shriwise, John Tramm and Amanda Lund.

Romano began developing OpenMC more than a decade ago as an MIT graduate student. He is now a computational scientist at Argonne, and he and others at Argonne and MIT have grown OpenMC into a widely used tool for advancing both fission and fusion research. ​“It can predict, for example, how quickly nuclear fuel will be consumed or how much damage radiation will cause to reactor materials,” Romano said.

Together, these three projects represent a comprehensive approach to modernizing nuclear energy. They address fundamental challenges in reactor physics and the need for accessible, open-source tools and introduce an innovative design for hydrogen containment. Argonne’s researchers have pushed the boundaries of what is possible in nuclear technology, demonstrating that safety, efficiency and innovation can go hand in hand.