InTheNews

 

​By Tiffany Adams

The passion Jackson Harter has for his research is evident within minutes of talking to him. However, Harter's entry into the world of research was unconventional.

Originally working in the culinary industry, including teaching at the Western Culinary Institute for two years, Harter began his undergraduate degree at 25 at Oregon State University (OSU). Although he knew going to school would be better for his health (Harter has Type 1 diabetes and had difficulty managing his health while working long hours in the kitchen), the transition from working in kitchens to learning in a classroom was not always smooth. "I had a particularly hard time the first two years of undergrad," Harter said. "I think I retook three classes."

Now almost nine years later, Harter finished the third year of his nuclear engineering Ph.D. at OSU and is an intern in the Reactor Physics Design and Analysis group at Idaho National Laboratory. As part of his doctoral research, Harter is adapting Rattlesnake, a neutron transport code, to simulate phonon behavior. As Harter explains it, phonons are "a collection of quantum acoustic waves in crystalline solids," analogous to sound waves, and are the dominant carriers of energy in solid, insulating materials. By simulating phonon transport, researchers can use these models to predict temperature gradients and thermal conductivity in oxide nuclear fuels, and characterize phonon scattering in and around defects generated during fission.

"Phonon transport is a very difficult phenomenon to model correctly, and there are many different approaches to doing so," Harter said. One of the most popular methods is Monte Carlo. Although Monte Carlo provides reliable solutions, it is generally prohibitively slow to use. Using Rattlesnake with the alterations Harter has made, researchers are able to get results for similar problems that match very closely with Monte Carlo solutions, but do so in a fraction of the time. "The advantage to our approach is that we maintain a high degree of accuracy, while increasing efficiency," Harter said.

The application of this research is wide and varied. From the processors in cellphones to the fuel in light water reactors, understanding how phonons behave in materials is key to continuing to improve efficiency and strength of materials. In addition to his work at INL and with OSU, Harter also works with the Computational Materials Group at the University of California, Riverside, led by assistant professor Alex Greaney. This research group provides material property data that Harter then uses to improve and refine his code. In turn, Harter supports their work by performing phonon transport simulations of new thermoelectric materials they are investigating to be used in the radioisotope thermal generators that power deep space probes such as the Mars Curiosity rover.

Although quite different from coding or theory development, Harter values the lessons he learned during his time working in restaurants and teaching culinary school. From people skills to his strong work ethic, Harter thinks a lot of what he learned is particularly applicable to his current life as a doctorate student. "Sometimes in our research you follow a rabbit down a hole for two or three months, and then it turns out there wasn't a rabbit in the first place," Harter said. "Working in the culinary industry, as well as having a chronic illness, both helped me to develop an attitude of not giving up."

While he still enjoys cooking for family and friends, Harter transitioned his enthusiasm for food to nuclear energy. "It turns out I'm even more passionate about nuclear engineering," Harter said