Internship program helps foster development of future nuclear scientists

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November 8, 2016 – For a second straight summer, Rachel Seibert spent her days at the Department of Energy’s Oak Ridge National Laboratory (ORNL) researching advanced nuclear reactors. The Ph.D. candidate may not have had such an opportunity more than a decade ago, but thanks to a unique internship program, Seibert analyzed tri-structural isotropic (TRISO) fuels and continued to pave the path toward her post-graduation career.

ORNL’s Nuclear Engineering Science Laboratory Synthesis (NESLS) program—a cooperative research initiative designed to encourage undergraduate and graduate students to pursue careers in nuclear science—launched in 2002 in response to a lack of potential engineers and researchers in the discipline. NESLS has grown from two participants that first summer to dozens of students each spring, summer, and fall semester.

This year’s summer semester saw 39 students from across the country spend 10 or more weeks working with an ORNL mentor. Across the Nuclear Science and Engineering Directorate (NSED), students could be found working on nuclear security, radiation shielding, facility safety, medical isotope development, and many other nuclear-focused areas.

“We want to diversify the background of our students and give them a well-rounded experience while they’re here,” said Julie Ezold, californium-252 program manager and chair of NSED’s Education Committee. “For undergraduates, it is opening that door and experiencing a national lab. For our graduate students, it is helping them focus on specific areas around their advanced degrees.”

The selection process takes into account a variety of factors­—such as the mentor’s ability to support a student, a student’s area of interest, and opportunities for a project that would fit into the mentor’s current research. This summer, 700 students applied to take part in the program.

In addition to the opportunity to take part in a research project, students receive a travel reimbursement and weekly stipend. They also attend a lecture series featuring leading experts from various backgrounds, tour ORNL’s facilities, and present their work during a poster session, where their research and presentation skills are judged.

“There’s a lot of value in standing up and giving a talk about what you have done,” Ezold said. “It’s all a part of making it a great experience, so they’ll become ambassadors of ORNL and go back and tell their universities what they did over the past few months.”

Seibert, a fourth-year student from Illinois Institute of Technology, finished as the runner-up in this summer’s poster session. Her poster highlighted the second year of her work with ORNL mentor Kurt Terrani.

With a background in physics and condensed matter, Seibert was a natural to work alongside Terrani, a nuclear fuels expert and Weinberg Fellow. As part of Terrani’s team, Seibert was tasked with investigating TRISO particles—a promising fuel type for next-generation high temperature gas-cooled reactors—by studying several interfaces of the fuel particle through transmission electron microscopy and energy dispersive x-ray spectroscopy.

The fuel comprises four separate layers—a carbon buffer, then a silicon carbon (SiC) layer sandwiched between two pyrolytic carbon layers. After analyzing the inner side of the SiC layer last summer, Seibert’s 2016 work looked at the middle and outer SiC interfaces. Seibert’s research is examining the fuels reaction specifically in accident conditions, with temperatures greater than 1600 degrees Celsius.

“We want to know how the fission products are interacting with the SiC, since it is the backbone of TRISO nuclear fuels,” Seibert said. “It’s important research to make them inherently safe and move one step closer to use in a reactor.”

Because the research continues to show promise, Seibert will remain at ORNL through the coming year as an intern outside of the NESLS program; such an arrangement is common when the partnership proves promising for the student and mentor. Seibert will continue to contribute to Terrani’s work but will also use the analysis in completing her dissertation—something she knows would not have been possible without NESLS.

“It is an absolutely amazing program. The facilities you have access to when you come in as a summer student are incredible,” she said. “And you not only have all of this equipment at your fingertips, but also staff, the people who work here. Everyone is a leading expert and willing to help you learn.”

For more information about NESLS, visit

Seibert’s internship was sponsored by the DOE Office of Nuclear Energy through the Nuclear Science User Facilities and the Advanced Fuels Campaign. ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE’s Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit