Author: The Kernel, and Charlie Maitland
Even in a room full of experts dedicated to the idea that nuclear should lead our clean energy future, there are plenty of conflicting opinions on how it could happen. “No Fuel, No Party” inspired by the old “no martini, no party” TV ad with George Clooney, was a nuclear energy symposium held recently by the MIT Center for Advanced Nuclear Energy Systems (CANES), specifically focused on nuclear fuel. Tensions within the nuclear fuel community centered on TRISO manufacturing, the proliferation risk of HALEU fuel, and the classic debate between large and small reactors. “Harnessing the unlimited potential of uranium to supply clean energy to the world,” the conference tagline, was itself a source of opposing views. Dialogue on these issues played out over the backdrop of nuclear’s recent trajectory of success while incredible challenges loom ahead.
Dr. Jacopo Buongiorno, the director of CANES, set the tone for the conference. Despite recent wins for nuclear, including the IRA and big tech PPAs, the topic of fuel is “not meant to be cheerful,” according to Buongiorno. “By interesting, I mean it’s ugly,” he said as he pulled up a graph of projected nuclear fuel costs. The cost of standard uranium dioxide fuel for large light water reactors has recently tripled due to a combination of underinvestment in the mining/enrichment/conversion supply chain, and the cutoff of Russian fuel supply following the invasion of Ukraine. On a levelized basis, these increased costs are dwarfed by TRISO, which is 5 to 6 times more expensive per MWh produced when used in various microreactors. Fabrication costs make up roughly one third of the cost of TRISO, a cost not born by traditional fuel types, as engineered coatings must be applied to the TRISO pebbles. Manufacturing TRISO is challenging and expensive, and the morning’s speakers agreed that scaling production is the best path to lowering unit costs (a conclusion that conflicted with one presenters suggestion that we should customize the fuel type to every reactor). Kairos power is building such a facility with plans to produce TRISO in large quantities. Dave Petti, a recently retired Idaho National Laboratory (INL) scientist, pointed out multiple times that Kairos has never made TRISO before, highlighting his skepticism. An enthusiastic MIT professor in the audience took issue with his attitude, exclaiming how they are already “pouring concrete.” It’s still too soon to tell whether or not TRISO costs will come down, and if they do, who will lead production, the incumbent BWX Technologies (BWXT), or new players like Kairos.
While Kairos has an agreement with Google, BWXT has been making reactors for the Navy and the fuel to power them for many years. Since these naval reactors use highly enriched uranium (HEU), capable of use as a weapon, BWXT operates a highly regulated and secured level 1 certified facility. Low enriched uranium (LEU), the nuclear fuel for traditional light water reactors is produced in much less regulated level 3 facilities. BWXT’s level 1 certification makes them overqualified for producing HALEU fuel. Factories dedicated to this task will need to be level 2 certified. Several speakers indicated that the level 2 certification will be much closer to the level 1 requirements than level 3. Large quantities of HALEU will need to be produced to economically support the higher fixed costs of a certified facility. A question of physics looms behind regulatory decisions for HALEU fuel. “Is HALEU a proliferation risk?” was the title of a talk given by MIT professor Dr. Scott Kemp. Using equations derived during the Manhattan Project, he showed a rough estimate of how many tons of HALEU would be required to make a fission bomb. While heavy and impractical, the possibility has been enough to provoke the NNSA to do a further study using their classified calculation tools. Several experts in the audience raised objections to the accuracy of the physical modeling efforts and proliferation risks of HALEU.
Dr. Kemp appealed to the audience with a practical argument. If we don’t get ahead of proliferation related regulatory hurdles, we could have a similar situation to the handling of plutonium when fuel recycling was attempted in the past. Significant resources were wasted when recycling efforts were halted as a result of proliferation fears. Interest in nuclear fuel recycling has not gone away. While conference organizer Dr. Buongiorno openly stated his preference for once-through fuel cycles, Dr. Temi Taiwo, director of the nuclear science and engineering division for Argonne National Laboratory, dedicated his entire presentation to fuel recycling. While the conference title alludes to an unlimited supply of energy from Uranium, the fuel supply is not infinitely abundant. Assuming 5000 GW of nuclear (80% of projected 2050 electricity demand), using a traditional fuel cycle would run through estimated Uranium reserves in just 24 years. Recycling fuel via breeder reactors would extend Uranium resources past 3000 years.
Such projections don’t mean anything if nuclear can’t get built. In the last presentation of the day, Duke Energy’s Chief Nuclear Officer (CNO), Kelvin Henderson had motivating words. Despite recent wins for the nuclear industry, paraphrasing “it’s too early to pat ourselves on the backs, we haven’t built a damn thing yet!” Duke Energy does have plans to build. With goals to be 50% decarbonized by 2030 and net zero by 2050, Duke is planning to build 6 small modular reactors (SMRs) on land adjacent to an existing coal power plant. The first question following the talk came from James Krellenstein, who asked why traditional large light water reactors are not being considered given their lower per MWh costs (and that the site and surrounding grid has room for large reactors). Henderson admitted his preference for larger reactors, but the utility is choosing SMRs to spread out the capital expenditures. The tension between small and large reactors has become well known in nuclear circles, and the Duke Energy CNO’s statement confirms that SMRs are an engineering solution to a financial challenge.
From TRISO fueled microreactors to uranium dioxide fueled GW scale power plants, this fuel themed symposium covered nearly every niche within the nuclear industry. They all represent a vision for the future of nuclear, and it was clear that the audience brought a range of opinions on what that future will be. While there were talks on laser enrichment, optimized fuel fabrication (apparently the TRISO fuel, now coveted for small reactors, was originally designed for large gas cooled reactors), and 3D printing fuels with embedded sensors, I tend to be most interested in practical, applicable, ideas. I was most excited when I learned that the US nuclear fleet has the potential to add 3 GW of capacity via uprates to existing plants, and that “advanced nuclear fuel,” as defined by the recent ADVANCE act, are for large light water reactors too. Existing plants can take advantage of fuel with LEU+ enrichment (up to 10%) and improved cladding, allowing for 24 month refueling schedules. These fuels are so applicable, they are already being used. Now THAT is a nuclear timeline I like to hear about!
