Nuclear generation assessment for Alaska's Railbelt

August 24, 2023

Image description below image in caption
Photo by Kathryn Modler
ACEP intern Gus Lewis (far left) at Gaalee’ya Spirit Camp watching fellow interns jump into the Tanana River.

This article is part of a series highlighting ACEP’s 2023 cohort of eighteen undergraduate interns. To read about other projects and learn more about the program, please visit the ACEP Internship Program website.

Gus Lewis, born and raised in Anchorage, Alaska, is an upcoming senior at the University of Alaska Anchorage, pursuing a bachelor of science in electrical engineering and a minor in mathematics.

Lewis worked under Phylicia Cicilio on her Railbelt Decarbonization project. The project is investigating potential technologies that can contribute to reaching a carbon-emission-free goal by 2050 along the Alaska Railbelt transmission system, commonly known as the Railbelt. The state's lone transmission system, the Railbelt provides nearly 2,000 MW of installed generation capacity and spans roughly 700 miles. Lewis explicitly looked at implementing Nuclear Small Modular Reactors (SMRs) as a method of decarbonization.

SMRs are nuclear reactors ranging up to 300 MWe — megawatts electric, or the output power obtained as electricity — in size and provide clean dispatchable electricity. These machines utilize energy from a controlled nuclear chain reaction to produce steam to power a turbine to generate electricity. SMRs are not a renewable energy source, and unlike other variable resources such as wind and solar, SMRs can be ramped up or down depending on demand.

While there has been substantial research at ACEP into micro-reactors (SMRs designed to generate up to 10 MWe), implementation on a large scale, such as throughout the Railbelt, is relatively foreign. If there is genuine interest from Alaska and other parts of the United States in becoming carbon-neutral by 2050, research into large machines capable of dispatching significant sums of electricity, such as nuclear SMRs, should be paramount. One of the most considerable challenges nuclear power faces is public perception. Producing work to allow familiarity and knowledge of the technology to the general public is essential.

This is Lewis's second summer internship with ACEP. In summer 2022, he completed similar work under David Denkenberger, where he looked at the implementation of various nuclear micro-reactors, the largest being 5 MWe, at islanded grids — local electric grids that are not connected to a wider electric power system — throughout Alaska.

Lewis expected a significant overlap between his research last year and what he would work on this year. Surprisingly, this summer was “a completely different endeavor” for him while there were benefits of having familiarity with SMRs.

This summer, “we have been trying to produce models and generate enough nuclear power to fully decommission natural gas and coal-fired plants on the Railbelt. The task of this summer's work has just been on a completely different scale and is very difficult to relate to my previous work with micro-reactors,” Lewis said.

Lewis’s “deepened understanding of how grids function and how all the various technologies puzzle-piece together” was his biggest takeaway from this summer’s internship, “all of which I can attribute to working with Dr. Cicilio,” he reflected.

This internship is funded by the Office of Naval Research through the ACEP Undergraduate Summer Internship program. View the final presentation for this project on ACEP’s YouTube Channel. For more information on this project, please contact Phylicia Cicilio at