Featured Post from VCU College of Engineering

Researcher to build fuel database to improve nuclear reactor sustainability

Nov 17, 2022

3 min

Braden Goddard, Ph.D.Zeyun Wu, Ph.D.

Braden Goddard, Ph.D., assistant professor in the Department of Mechanical and Nuclear Engineering, has received a grant from the U.S. Department of Energy’s Nuclear Energy University Program (NEUP) to create a database for use in nuclear material control of pebble bed reactors (PBR).


Advances in material science and technology have revitalized the nuclear energy industry, allowing for the design and construction of advanced nuclear reactors. New high-temperature materials developed by researchers allow ideas from as early as 1970, like pebble bed reactors, to be re-explored and make nuclear power more efficient and sustainable.


Pebble bed reactors are one of many ideas from as early as 1970 that researchers are once again exploring to make nuclear power more efficient and sustainable now that science has developed new high-temperature materials.


“Imagine a gumball machine,” said Goddard, “A pebble bed reactor functions similarly. The pebbles are the gumballs, which are fed into a reservoir. As they make their way through the reactor, heat generated from the radiation is removed by a gas which then spins an electrical turbine to generate electricity. The pebbles then exit from the bottom of the reservoir and those that can be reused are returned to the top of the reservoir.”


Each pebble contains thousands of microscopic uranium particles encased in silicon-carbide cladding. As the pebble passes through the PBR, the path it follows affects how much fissioning occurs within the uranium. This means pebbles deplete at different rates based on how they travel through the reactor.


Goddard’s database seeks to characterize the state of a pebble after it leaves the PBR by determining precisely how much plutonium and uranium remains in the pebble. This informs PBR operators if the pebble can be reused or if it needs to be sent off as waste. Better characterizing these pebbles improves the sustainability and security of PBRs while reducing the amount of waste generated.


Measuring gamma radiation from the radioactive isotope cesium-137 created from the fission of uranium is the traditional method of determining how much nuclear fuel is still viable. However, this system does not work for PBRs because the correlation between the uranium fuel and the gamma radiation it emits is not consistent between pebbles. To remedy this, Goddard will measure both gamma and neutron radiation emitted by all radioactive isotopes in the pebble, which varies depending on the route the pebble takes through the reactor. Partners like Brookhaven National Laboratory and similar institutions within the United States will assist in the research by applying machine learning techniques to the gamma and neutron radiation signature.


“Nuclear reactor operators have instruments that tell them what’s going on inside the reactor, but it’s not the same as knowing how much uranium mass you have in fuel going into or coming out of the reactor,” said Goddard.


Goddard and his colleague, Zeyun Wu, Ph.D., will use computer modeling to run countless simulations and map every possible course a pebble can take through a PBR. The resulting catalog of data will allow PBR operators to characterize the state of any pebble leaving the PBR and assess if it can be reused or if it is ready to be stored at a nuclear waste facility. The catalog also serves as a material inventory, allowing nuclear facilities to better track waste material.

Connect with:
Braden Goddard, Ph.D.

Braden Goddard, Ph.D.

Associate Professor, Department of Mechanical and Nuclear Engineering

Professor Goddard is a nuclear engineer specializing in nuclear security and nonproliferation.

Nuclear EngineeringEnvironmental measurements and assayRadiation detection and measurementsNonproliferation and international safeguardsNuclear security and counter terrorism
Zeyun Wu, Ph.D.

Zeyun Wu, Ph.D.

Associate Professor, Department of Mechanical and Nuclear Engineering

Reactor physics, computational methods, sensitivity and uncertainty analysis, advanced data analytics, machine learning

Nuclear EngineeringAdvanced data analyticsUncertainty and sensitivity analysisComputational method for neutron transportReactor core design and analysis
Powered by

You might also like...

Check out some other posts from VCU College of Engineering

Department of Energy awards $928,000 to Lane Carasik, Ph.D., for fusion energy systems research featured image

2 min

Department of Energy awards $928,000 to Lane Carasik, Ph.D., for fusion energy systems research

The Department of Energy (DOE) recently announced $128 million of funding for seven Fusion Innovation Research Engine (FIRE) Collaboratives. Virginia Commonwealth University (VCU) College of Engineering researchers will support the project titled “Advancing the maturity of liquid metal (LM) plasma facing materials and first wall concept” led by the Department of Energy’s Princeton Plasma Physics Laboratory (PPPL). This includes $928,000 to support research led by Lane Carasik, Ph.D., assistant professor in the Department of Mechanical and Nuclear Engineering, as part of a multi-institution effort for fusion energy systems. The FIRE Collaborative seeks to advance the maturity of liquid metal plasma-facing materials and wall concepts. High operating temperatures within fusion energy systems pose a significant material design challenge. Research will help solve technical problems with liquid metal plasma-facing materials and first wall concepts, including four main challenges: testing protective materials, understanding material properties, studying how liquid metals behave in magnetic fields and developing new liquid metal alloys. The goal is to make liquid metals viable for fusion pilot plant designs. “The work done by VCU as part of the FIRE Collaborative will help raise the technology readiness of Liquid Metal based fusion energy concepts. Over the next four years, we will train undergraduate and graduate students on how to extract electricity from these fusion concepts,” Carasik said. Rajesh Maingi, Ph.D., is the lead primary investigator at PPPL. Institutional investigators for the group include Sergey Smolentsev, Ph.D., Oak Ridge National Laboratory (ORNL); Vsevolod Soukhanovskii, Ph.D., Lawrence Livermore National Laboratory (LLNL); Daniel Andruczyk, Ph.D., University of Illinois Urbana-Champaign; Bruce Koel, Ph.D., Princeton University; Michael Kotschrenreuther, Ph.D., ExoFusion; Xing Wang, Ph.D., The Pennsylvania State University; Kevin Woller, Ph.D. from Massachusetts Institute of Technology; and Carasik from VCU. Up to $220 million is expected to fund the FIRE Collaboratives over four years, with $31 million allocated for the 2025 fiscal year. Future distributions are dependent on congressional appropriations.

Mechanical and Nuclear Engineering professor John Speich, Ph.D., advances bladder biomechanics research through collaboration with VCU School of Medicine featured image

3 min

Mechanical and Nuclear Engineering professor John Speich, Ph.D., advances bladder biomechanics research through collaboration with VCU School of Medicine

The year was 2003, and John Speich, Ph.D., professor in the Department of Mechanical & Nuclear Engineering, felt like he had a clear sense of the direction his burgeoning career was heading in. Speich had recently completed his doctorate in mechanical engineering from Vanderbilt University, where he concentrated on robotics. Following Vanderbilt, Speich went on to become an associate professor at the Virginia Commonwealth University (VCU) College of Engineering, working with students in the Department of Mechanical & Nuclear Engineering. Leveraging his robotics expertise, Speich planned to continue his work developing robotics for medical surgery and rehabilitation. Then Speich got a call from Paul Ratz, Ph.D., a professor at the VCU School of Medicine, asking for assistance that would change the entire focus of Speich’s career. Ratz used a small robotic lever that moved up and down just a few millimeters to stretch tiny strips of bladder muscle and rings of artery, trying to determine how different chemical compounds changed the mechanical properties of the muscle. Speich was intrigued—this was a form of mechanical engineering. “In mechanical engineering, we pull on things to determine the mechanical properties,” says Speich. “Here, Dr. Ratz was pulling on pieces of bladder instead of the typical substances mechanical engineers are known to work with, like steel, aluminum or plastic.” Speich and Ratz began working together in 2003, and now, because of that unique partnership, nearly all of the research Speich does is about the bladder. “Before I started working with Dr. Ratz, I had never even heard the words neurourology or urodynamics,” says Speich. “Now, Neurourology and Urodynamics is the name of the journal I publish in the most.” Today, Speich collaborates on bladder biomechanics with two doctors at VCU Health. Adam Klausner, MD is a urologist and the interim chair of the new Department of Urology at VCU. Linda Burkett, MD is a urogynecologist from the Department of Obstetrics and Gynecology; prior to medical school, Burkett completed her bachelor’s degree in Biomedical Engineering from the VCU College of Engineering. Together, Speich, Klausner and Burkett aim to find non-invasive methods to characterize and diagnose overactive bladder, with the goal of allowing doctors to precisely match patients with the most effective treatments. A number of students across the VCU College of Engineering and VCU School of Medicine have aided in their research, including recent Biomedical Engineering graduate Mariam William. Speich’s primary methods of research involve Near-Infrared Spectroscopy (NIRS)—a non-invasive technology that uses light to measure tissue oxygenation and brain activity—and ultrasound imaging. By using NIRS to study the brain activity associated with the sudden urge to urinate, Speich and his team are working to pinpoint the brain’s role and determine whether it or the bladder is the primary cause of an individual’s condition. “There are a lot of potential causes of overactive bladder,” says Speich. “Some people may have more than one cause. Individual responses to these treatments vary; what works well for one patient may not work at all for the next. We want to give doctors better tools for quantifying information about their patients so they can make better decisions and more optimized treatments.” Thanks to research grants, including a National Institutes of Health (NIH) grant from 2015-2025, Speich has been able to make a number of important findings in his bladder research. His team has closely examined the bladder’s dynamic elasticity, investigating the biomechanical mechanisms that allow the bladder muscle to fill and expand. Another recent focus asks, “Bladder or Brain. Which is it?” Speich and his team developed a tool called a sensation meter that they use to help determine what an individual is feeling as their bladder is filling over time. All this groundbreaking research and medical school collaboration, and to think—Speich nearly missed the opportunity to enter this field entirely. “When I tell students about how I came to be involved in bladder biomechanics, I tell them, you will always keep learning throughout your entire career,” says Speich. “You never know where you’re going to end up. If you’re an engineer, you’re a problem solver, and there are all kinds of problems in areas like business and medicine—beyond the traditional areas people think of when they think of mechanical engineering.”

VCU College of Engineering receives $4.5 million of funding for research supporting blind-visually impaired individuals featured image

2 min

VCU College of Engineering receives $4.5 million of funding for research supporting blind-visually impaired individuals

Pioneering systems to aid the visually impaired, Dianne Pawluk, Ph.D., associate professor in the Department of Biomedical Engineering, recently received two grants totaling $4.5 million in support of her research. Real-time Conversion and Display of Visual Diagrams in Accessible Forms for Blind-Visually Impaired (BVI) is a five-year project to develop real-time assistive technology for BVI individuals. It received a $3.2 million grant from the National Institutes of Health’s National Eye Institute to fund a low-cost system that will automatically convert and render visual diagrams in effective accessible formats on a multimodal display, including a refreshable tactile display and an enhanced, visual magnification program. Diagram exploration support will be provided by an automated haptic assistant. Pawluk is collaborating with Tomasz Arodz, Ph.D., associate professor in the Department of Computer Science, on the project. Including Blind and Visually Impaired Students in Computer Programming Education Through a Tangible Interface for Scratch is a four-year project to develop a nonvisual interface for the Scratch programming platform. Receiving a $1.3 million grant from the National Science Foundation, the project aims to make computer science education more accessible to BVI students. The interface will allow these students to learn programming alongside their sighted peers in classrooms, camps and clubs, supporting both BVI and other kinesthetic learners with a haptic-based tangible interface. High contrast visual information will also be provided for those with low vision and collaboration with sighted peers. This project is a collaboration with the Science Museum of Virginia, Arizona Science Center and Liberty Science Center. “Equal access to information is important for individuals who are blind or visually impaired to have autonomy and control over their decision-making processes and other tasks, which will allow them to live productive and fulfilling lives,” Pawluk said. “These projects go beyond creating an equivalent experience. They enable full collaboration between visually impaired and sighted people, ensuring equal opportunity.”

View all posts
Powered by