Centrus Energy: The American Nuclear Fuel Supplier
Will Centrus finally revive domestic, US-owned, uranium enrichment capacity?
Centrus Energy Corp (NYSE: LEU) provides uranium products for nuclear reactors and engineering services for public and private companies. They currently act as a broker for reactor owners to deliver enriched uranium for fuel fabrication, work with the Department of Energy (DOE) to produce High-Assay Low Enriched Uranium (HALEU), and assist nuclear and industrial companies with various engineer projects and studies.
There has been significant churn lately in regards to the security of nuclear fuel supplies for America's commercial reactor fleet. The war in Ukraine, followed by import restrictions in the US and export restrictions in Russia, have highlighted the US's current lack of domestic, American-owned, uranium enrichment capacity. It used to be present, running for decades to supply both government and commercial needs. Where did our enrichment capacity go, and why? What is the plan to get it back?
The History of American Enrichment
Centrus has only been around in its current form since 2014, but it can trace its lineage all the way back to the Manhattan Project. Given the topic of uranium enrichment isn’t exactly common knowledge, we’ll reference a description from a previous article of ours titled “The Nuclear Reactor for Investors”:
The enrichment in nuclear fuel refers to the percentage of fissionable, or fissile, material in the fuel. This fissile material is the uranium isotope U-235, with the majority of the rest of the uranium in the fuel being non-fissile U-238. Enriched fuel is usually required, since natural uranium mined from the ground is around 0.7% U-235, and most reactors need enrichment levels around 3-5%. The sub-5% enrichment level is referred to as Low Enriched Uranium (LEU). Some of the newer commercial reactors though require High-Assay LEU (HALEU), which is enriched to around 15-20% U-235. There are even higher levels of enrichment, usually reserved for government-sponsored research and military use due to proliferation concerns.
1940s and 1950s
Highly Enriched Uranium (HEU), the above mentioned government/military grade enrichment level, was needed to fuel the Little Boy bomb. So, the US government commissioned multiple enrichment plants in Oak Ridge, TN, including Y-12, S-50, and K-25, to produce uranium with about 80% U-235 enrichment levels. The plants used a variety of enrichment technology:
Y-12 used Electromagnetic Separation, also known as the calutron method, which ionized uranium tetrachloride gas and passed them through a magnetic field. The atoms had their paths bent differently based on mass, curving the U-235 away from the U-238
S-50 used Thermal Diffusion used a temperature difference on uranium hexafluoride in a tube, causing U-235 to concentrate on the hotter material
K-25 used Gaseous Diffusion to force uranium hexafluoride through a porous barrier, which took advantage of the slight mass difference between U-235 and U-238. This is the method the US decided to retain after the Manhattan Project
In 1947, the Atomic Energy Commission (AEC) took over K-25 gaseous diffusion plant, as Y-12 and S-50 had already shutdown by this time. The AEC oversaw the expansion of enrichment in Kentucky and Ohio at Peducah and Piketon sites in the early 1950s, enabling them to further supply the nuclear weapons program, and later, the commercial nuclear fleet.