Kathryn Huff, the Department of Energy’s acting assistant secretary for nuclear energy, asserted in an article published online by the Office of Nuclear Energy (DOE-NE) on July 30 that demonstration reactors, such as the Natrium and Xe-100 reactors being built as full-size power producers with cost-shared funding from the DOE, and test reactors, such as the Versatile Test Reactor, are both necessary for nuclear innovation. Both are also line items in the DOE budget request, and Huff’s article sends a clear message to appropriators about the need to fund both the Advanced Reactor Demonstration Program (ARDP) and the VTR.
Clear imperative: “The impacts of climate change are playing out in real-time all over the world, including in the United States,” Huff said. “We simply can’t wait any longer, and Secretary Granholm has made it crystal clear that we need to deploy all existing and new technologies now in order to temper these impacts. That must include innovations in nuclear energy.”
While innovative advanced reactors will be operating within the decade, “In order to innovate faster and improve upon these designs over time, we also need the necessary infrastructure to support their development and, more importantly, their commercial deployment,” Huff said. “This unique challenge is both a sprint and marathon at the same time, which is why we need reactor demonstrations and a new test reactor to facilitate the future growth of these technologies.”
Fast and feasible: Successful ARDP demonstrations of TerraPower’s Natrium (a sodium-cooled reactor) and X-energy’s Xe-100 (a high-temperature gas-cooled reactor) will prove that advanced reactor technology works as intended, yet those demos are only part of a continuing innovation cycle. While the Advanced Test Reactor and other DOE test reactors have supported nuclear innovation for decades, they cannot sustain neutrons at concentrations and speeds high enough to perform accelerated testing of innovative nuclear technologies, Huff explained.
“Faster testing will allow scientists to test multiple ideas quickly, identify what works, and make refinements that yield innovations to support the safer and more economical operation of nuclear power plants,” Huff said. “As we move from demonstrations to widespread commercialization, we need a fast neutron test reactor that can support research for all stages of technology development—including the existing fleet of commercial reactors.”
Once built, the VTR could provide a high flux, fast neutron environment to support accelerated fuels and materials experiments for 60 years. Without the VTR, Huff said, “U.S. innovation will fall behind other countries which have fast neutron test reactors, and we simply can’t let that happen.”
A marathon and a 100-meter dash: FAQs posted on Idaho National Laboratory’s VTR webpage provide more details and explain that while the VTR is based on a sodium-cooled reactor design that is very similar to Natrium, it can’t be combined with the Natrium ARDP demonstration because “their principal missions, and therefore their detailed designs, are very different.”
TerraPower’s Natrium reactor is designed to produce power and will “utilize long-lasting fuel for operating cycles generally exceeding one year or more between refueling events.” The VTR, on the other hand, will use “high-performance fuel with 100-day operating cycles, followed by a 20-day outage to refuel and replace experiments.”
INL characterizes the Natrium demo as being fueled for a marathon and the VTR for a 100-meter dash: “Trying to combine these two different missions will result in a reactor that is not efficient at either producing power or providing an advanced irradiation testing environment.”
Background: DOE-NE established the VTR program in 2018 in response to the Nuclear Energy Innovation Capabilities Act. The DOE approved the mission need for the VTR in February 2019, and in September 2020 it approved Critical Decision 1, which is the second step in the formal process the DOE uses to review and manage research infrastructure projects. The environmental review process began with the release of a draft environmental impact statement (EIS) for public review and comment in December 2020; the initial 45-day comment period was later extended into March 2021. The DOE will make a final decision regarding the VTR following the completion of the EIS and the issuance of a record of decision, which is expected in late 2021.
An earlier version of the article incorrectly stated that Kathryn Huff was the DOE's assistant secretary, it has been updated to show that she is the acting assistant secretary for nuclear energy. We apologize for the error.