The TCR program is leveraging an agile approach—one that is centered around continuously informing the process—to accelerate deployment timelines and introduce performance improvements. Image: Adam Malin, ORNL

Soon after Enrico Fermi’s Chicago Pile-­1 went critical for a brief duration in December 1942, the construction of the first continuously operating reactor, the X-­10 Graphite Reactor, was initiated in February 1943 at Clinton Engineer Works in Oak Ridge, Tenn. On November 4 of that year, a mere nine months after the start of construction, the reactor began operation. This marked the onset of what Alvin M. Weinberg referred to as “the first nuclear era,” during which many reactors of various designs and operating parameters were built and demonstrated across the United States. Forty years ago, the Fast Flux Test Facility was the last U.S. non-­light-­water reactor to reach criticality, and it has since been decommissioned.

On February 27, Sens. Lisa Murkowski (R., Alaska) and Joe Manchin (D., W.Va.) introduced the American Energy Innovation Act (AEIA), a 555-­page piece of policy legislation that incorporates over 50 energy-­related bills considered and individually reported by the Senate Energy and Natural Resources Committee last year—measures sponsored or cosponsored by more than 60 senators from both sides of the aisle.

This week I had some considerable interaction on social media in the area of replacing fossil power at existing sites with micro reactors or SMR’s (Small Modular Reactors.) As we see real progress happening now in these exciting reactor fields (NuScale and Oklo come to mind first, but there are others!) I’d like to share five things to think about as we begin to seriously consider replacing fossil power (coal, oil) at particular sites with nuclear.

Advanced reactor cores are being designed for higher efficiencies and longer lifetimes, but to get there, they need high-assay low-enriched uranium (HALEU).

Enriched to between 5 and 19.75 percent fissile U-235, HALEU is packed with nuclear potential. It can be used as a feedstock for the demonstration of new fuel designs, from uranium alloys to ceramic pellets and liquid fuels. Those fuels can enable advanced reactor and microreactor demonstrations. Operating light-water reactors could potentially transition to HALEU uranium oxide fuels for extended operating cycles and improved plant economics.