Purdue Nuclear Engineering has a long and storied history. Established in 1960, its acclaimed faculty conduct pioneering research in world-class research facilities. It houses Purdue University Reactor One (PUR-1), the first and only nuclear reactor in Indiana, for both research and education.

Small modular reactors, digital twins, advanced manufacturing

As a groundswell builds for nuclear power to generate more of the nation’s electricity, there is a shortage of nuclear engineers and other workers to power that resurgence. A U.S. Department of Energy forecast sees nuclear power tripling by 2050, and based on that forecast today’s workforce of 68,000 needs to grow to 200,000. New innovations are also needed to develop next-generation nuclear reactors, which are expected to cost less to maintain and last longer than today’s reactors.

That’s where the Purdue’s School of Nuclear Engineering comes in – a leader in nuclear power research, education, and training. The school is “where future leaders of the global nuclear engineering community are cultivated,” said Seungjin Kim, who heads up the school. “We educate ethical nuclear engineers to provide technical expertise to the nuclear engineering communities around the world, expand the frontier of knowledge through cutting-edge and innovative research in all areas of nuclear engineering, and dynamically engage with the global society through strong partnerships.”

Purdue Nuclear Engineering has a long and storied history. Established in 1960, its acclaimed faculty conduct pioneering research in world-class research facilities. It houses Purdue University Reactor One (PUR-1), the first and only nuclear reactor in Indiana, for both research and education. The school’s alumni are leaders in nuclear industries, governments, national laboratories, utilities, and educational institutions, both nationally and globally.

While Purdue’s School of Nuclear Engineering is a robust academy with many strengths, distinguished among them are three in particular: digital twin technology, leadership in developing small modular reactors at both the state and national levels, and advanced manufacturing technology.

“Small Modular Reactors offer innovative opportunities to expand Indiana’s energy generation portfolio,” said Indiana Governor Mike Braun. “Further exploration of SMR technology and its potential are imperative as we strive to be on the leading edge of energy modernization.”

“Purdue University plays a valuable role in advancing our understanding of energy research, deployment, and viable energy solutions.”

Digital Mastery: Paving a Path to the Future

Digital twins not only can help to increase the performance, efficiency, and safety of nuclear power plants but also help to alleviate any remaining concerns that might slow the more widespread adoption of nuclear energy.

“Digital twins are virtual representations of physical systems. They synchronize the digital model to the physical system operational cycle via continuous information flows that feed information from the physical to the virtual and vice versa. Digital twins provide valuable inputs about physical system operation with data that cannot be measured physically or predicted in the real-world system,” wrote Stylianos Chatzidakis and Vasileios Theos (Digital twins can strengthen case for nuclear energy). Chatzidakis recently disclosed this technology to the Purdue Innovates Office of Technology Commercialization (OTC). It will be available for distribution through the OTC website in the near future.

Chatzidakis is an assistant professor, associate reactor director for PUR-1, and director of the Nuclear Radiation (RADIaNS) Laboratory; Theos is a research assistant in the RADIaNS Lab. The two are conducting groundbreaking research into digital twins for nuclear energy, and have created a digital twin in a cyber-physical testbed within PUR-1, the first and only U.S. Nuclear Regulatory Commission (NRC) facility to be licensed for a fully digital safety and control system.

As the first all-digital nuclear reactor in the United States — and the first digital twin of a nuclear control system on a U.S. university campus — PUR-1 processes and analyzes streams of “big data” collected during reactor operation. Purdue Nuclear Engineering researchers have developed physics-based models and artificial intelligence/machine learning algorithms from reactor operational data to predict and monitor a reactor’s performance.

Pertinent data and analytics generated by the AI-infused digital twin model enables evaluation of critical factors such as the onset of material fatigue or damage, decision risks, expected component lifecycle, and safety and regulatory limitations.

The digital twin and experimental testbed allow Purdue Nuclear Engineering researchers and students to undertake a wide variety of experiments virtually without affecting the reactor’s operation. Having a detailed visual representation of the physical system to receive and process the reactor data enables capabilities such as remote control, monitoring, and cybersecurity research.

With support from a DOE grant, upgrades are underway for the Purdue University Multidimensional Integral Test Assembly, known as PUMA, the only existing scaled integral test facility for advanced light-water reactor. These advanced small modular light-water reactors use ordinary water as a coolant like the conventional large reactors, but they add advantages such as quicker and modular construction, smaller size, enhanced safety features, less waste generation, and potentially lower operating costs.

PUMA will be refurbished and given new capabilities, including a digital-twin system with a full-scale reactor control room. Researchers will be able to compare streamed operational data with computer predictions about the reactor system’s behavior to further advance the safety of advanced nuclear power plants.

Progress in these digital twin initiatives and other Purdue Nuclear Engineering research “will improve performance, uneventful operation and efficiency of a nuclear power plant, assisting in the energy transition,” state Chatzidakis and Theos. “We foresee that the enhanced performance of these plants, in turn, will contribute to an increase in public acceptance of nuclear energy.”

Small Modular Reactors, for State and Nation

Purdue Nuclear Engineering is a leader in the development of a new generation of small modular reactors (SMRs) at both state and national levels.

Purdue was awarded a $6 million grant from the U.S. Department of Energy (DE-NE0009516) to expand Purdue-led research into SMR and advanced reactor (AR) technologies. The group consists of five universities and colleges in two national labs, which will work to upgrade research facilities, increase their capabilities, and develop programs to educate the future nuclear energy workforce.

The project will establish new cyber-physical capabilities for a range of SMR and AR technologies. A user facility consisting of four interconnected cyber-physical facilities will be outfitted with state-of-the-art digital instrumentation and control systems and serve as a regional center of excellence for research, education and training. The center’s charter will emphasize sharing equipment and instrumentation among universities, national labs, industry partners and other institutions to conduct multidisciplinary research and demonstrations.

SMRs are riding a wave, with good reason.

Given their smaller footprint, SMRs can be sited on locations not suitable for larger nuclear power plants. They can be manufactured and then shipped and installed on-site, making them more affordable to build than large power reactors. Additionally, they have the potential to offer savings in cost and construction time, and they can be deployed incrementally to match increasing energy demand.

The advantages of SMRs include the lower costs plus simpler designs, lower fuel requirements, and improved “passive” safety systems that automatically shut down the reactor if there is a malfunction, reducing the potential for releasing radioactivity in the case of an accident.

Purdue and Duke Energy released an interim report that describes SMRs as one of the most promising emerging technologies that should be further studied to help meet the future, long-term power needs of Purdue’s campus. Purdue was also chosen by the Indiana Office of Energy Development to study the feasibility of SMR technology and its potential impacts for the state.

In conducting research that serves others, Purdue is also serving itself. While Purdue self-generates roughly half of the electricity needed to operate campus, the other half is purchased from the grid. Helping state-wide decision makers understand the potential benefits of SMR deployments within the state may lead to cleaner electricity on the state electric grid. Through studies like these, the research taking place today at Purdue may one day pave the way for lowering carbon emissions of Purdue’s West Lafayette campus.   

Advanced nuclear energy designs include some even smaller and more portable than SMRs. Like everything these days, small keeps getting smaller, hence the so-called “microreactors.” These have smaller footprints than other SMRs and will be better suited for regions inaccessible to clean, reliable and affordable energy, and could also serve as a backup power supply in emergency situations or replace power generators that are often fueled by diesel; for example, in rural communities or remote businesses.

Hitesh Bindra, a Purdue Nuclear Engineering associate professor, is conducting research that enables more widespread use of microreactors. These units can be deployed to a specific site and transported by truck in a standard shipping container (Truck-portable nuclear reactors go where the power is needed). Bindra and his team are looking at which manufactured packaged solutions can ensure safe transport, focusing on whether the reactors have sufficiently robust passive safety features and appropriately sized protective safety “envelopes” to secure them safely while in transit. His team also looking at ways to improve the design and economic performance of high temperature Small Modular Reactors.

Generating energy is only part of the equation – also critical is the power storage strategy that enables flexible distribution on demand. Bindra is also pursuing novel research into thermal energy storage systems (TESS) for SMRs, which are often paired in microgrids with renewable energy sources like wind to improve system reliability and reduce operational costs.

Bindra is investigating a bi-level operational planning model that enables microgrid planners working with SMRs and wind turbines to determine the best TESS technology and sizing. He is using simulation and stochastic optimization algorithms to determine the optimal energy storage technology choice for the microgrid based on the lowest size requirement and highest utilization factor. The goal is to mitigate grid variability across differing demand scenarios, in light of the high uncertainties of renewable energy production.

His findings indicate that without the implementation of energy storage, the required nuclear power capacity would need to be above the average grid load, and most of the wind power would be wasted. By implementing the energy storage solution using nuclear as a constant baseload, the wind power can account for a larger fraction of the grid. His research found thermal energy storage (TES) to be the superior energy storage system choice for the SMR-based microgrid due to its longer expected technology lifetime. His team is further looking to leverage the TESS technology to improve the deployment potential of SMRs by introducing security and safety design features.

Bindra also has a patent-pending innovation disclosed to the OTC.

Advanced Nuclear Manufacturing

The renaissance in nuclear power has been accompanied by the domestic manufacturing capacity and striking innovations in manufacturing and material technologies to tackle the challenges of producing the complex components that can operate in the extreme environments.

“Nuclear reactors operate in extreme service conditions, under stress from temperature, corrosion, radiation, and complex mechanical loading,” said Xiaoyuan Lou, associate professor of Nuclear Engineering, with a courtesy appointment in Materials Engineering. “The reactor structures primarily rely on various steels, stainless steels, and nickel-based alloys from which the components are made of to combat these conditions and sustain the operation. The choice of manufacturing process and material selection depends on the service conditions, cost, and design complexity.”

Conventional manufacturing of nuclear components involves a series of casting, forging and welding operations, which often increases the manufacturing cost and deployment schedule. These processes also increase the susceptibilities to environmental degradation in reactor environments, such as environmental cracking near welds.  Lou and his team are exploring additive manufacturing (AM), often referred to as 3D printing, to produce entire, integral component structures from a computer-aided design.

AM is the opposite of traditional “subtractive” manufacturing, where parts are cut to shape by removing material during machining. Instead, the AM process involves adding and bonding layers of material on top of one another, directed by instructions from a 3D model of the desired end part. Some different types of AM techniques include laser powder bed fusion, direct energy deposition, binder jetting, and others.

“Additive manufacturing opens the door to design freedom and new materials through its ability to manufacture more complex geometry that cannot be done by traditional production processes,” Lou said. Lou has been working on this for over a decade along with industry and national labs to support American Society of Mechanical Engineers code development, material qualification, and manufacturing innovation.

Besides AM, Dr. Lou’s team is also developing powder metallurgy hot isostatic pressing (PM-HIP) technology to construct large-size nuclear component and join dissimilar metallic components.  Industry is interested in using PM-HIP to produce large nuclear structures, such as reactor pressure vessels, for advanced reactors.  Different from the aerospace industry, the nuclear industry is particularly interested in medium or large size components.  Lou’s research aims to scale these technologies to a realistic choice for larger-run production.

Advancing the Cause of Nuclear Power

Digital twins, SMRs, advanced manufacturing… These are three of the pillar strengths of Purdue’s School of Nuclear Engineering. But the school is also conducting groundbreaking research and development — in collaboration with government and industry —on a multitude of additional fronts.

For example, Purdue Nuclear Engineering researchers are investigating new monitoring, imaging, and AI algorithms for cosmic ray muon tomography, to inspect the heavily shielded containers that store spent nuclear fuel. They’re researching the implementation of quantum key distribution for enhanced communication security in the nuclear industry. They are investigating the design and manufacture of 3D-printed sensors for monitoring operations in nuclear reactor environments. Researchers like Nuclear Engineering professor Allen Garner are also studying potential biomedical and national security applications.

These are but some of the exciting lines of investigation and strengths of Purdue Nuclear Engineering as it persistently pursues both incremental advances and giant leaps in nuclear energy. With these strengths, Purdue is taking the frontier of knowledge to new levels and ensuring the next generation of nuclear engineers is ready to dynamically engage all areas of nuclear research and innovation.