The U.S. Department of Energy announced Tuesday it has selected five nuclear startups — Oklo, Standard Nuclear, Shine Technologies, Flibe Energy, and Exodys Energy — to enter advanced negotiations to receive a portion of approximately 34 tons of surplus weapons-grade plutonium the government previously identified for disposal. The material was produced during the Cold War for use in atomic weapons; with nuclear stockpiles subsequently reduced, the U.S. has been storing it in high-security facilities ever since. Rather than permanent geological disposal, the administration is now pursuing conversion into reactor fuel. Energy Secretary Chris Wright, who previously served on Oklo’s board before resigning and divesting his shares upon joining the administration, said the initiative is part of the broader push to expand domestic nuclear energy. Oklo’s former board chair Sam Altman also stepped down from that role last year.
The five companies are pursuing different technical paths. Oklo’s reactor design can accept both conventional uranium fuel and plutonium, with the government material intended to power its first commercial units; its U.K. partner Newcleo plans to build a mixed oxide fuel (MOX) fabrication facility nearby. Exodys Energy is designing a reactor that can run on MOX — a blend of uranium and plutonium — while Flibe Energy is developing a reactor fueled by plutonium and other fission by-products. The approach is not without critics: Scott Roecker, a vice president at the Nuclear Threat Initiative, told the New York Times that other countries have attempted this and ultimately concluded weapons plutonium is more liability than asset. Plutonium-239’s 24,000-year half-life makes indefinite storage untenable, but the security implications of transporting and processing the material are significant. Each of the five startups must now complete negotiations with the government on transport, handling, and security protocols before any transfer can proceed.