By Kennedy Maize
The U.S. nuclear industry is pushing back against a possible independent National Academies scientific study of the weapons potential of new fuels for many advanced civilian reactor designs. On Jan. 2, the National Nuclear Security Administration (NNSA) announced that it is evaluating High Assay Low Enriched Uranium (HALEU) powerplant fuels – fuels made with uranium enriched to between 5% and 20% U-235. Conventional reactor fuel is less than 5% U-235.
NNSA is the U.S. nuclear weapons program, the most important and best-funded arm of the U.S. Department of Energy. It is in charge of the development and stockpile of nuclear weapons, nuclear nonproliferation and counterproliferation, oversight of three national laboratories and several weapons facilities, and providing the Navy with nuclear propulsion systems.
Many of the advanced nuclear designs, including plans for small modular reactors that are not based on light water reactor technology, are designed around HALEU fuels. These allow for higher power levels and longer fuel life, helping the economics of the reactors.
In the announcement, then-NNSA chief Jill Hruby said that NNSA “is currently finalizing plans to commission a National Academies report.” She also noted that NNSA collaborates with the International Atomic Energy Agency on nuclear nonproliferation. Hruby said, “NNSA recognizes that reactor type, fuel enrichment level, fuel quantity, and fuel form are important factors in evaluating proliferation risks and believes that risk-informed and adaptive approaches to the proliferation challenges inherent in nuclear energy are warranted.”
MIT
Hruby was responding to a June 2024 article in Science magazine by a team of nuclear experts led by MIT’s R. Scott Kemp, including nuclear physicist Edwin Lyman of the Union of Concerned Scientists, Mark Deinert of the Colorado School of Mines, legendary physicist and hydrogen bomb designer Richard Garwin, and Frank von Hipple of Princeton University, which raised the possibility of HALEU diversion from peaceful uses to weapons. Prior to that article, the general perception was that HALEU was entirely safe for civilian use and posed no weapons threat.
The Kemp Science article found that fuel enriched to above about 12% could be used to make bombs equivalent to those that destroyed Hiroshima and Nagasaki and ushered in the world of concerns about uncontrolled proliferation of nuclear weapons. Lyman told The Quad Report last week that Terra Power’s planned 345-MW Natrium sodium cooled fast neutron reactor demonstration will use uranium averaging 18.5% and Oklo’s Aurora 50-MW microreactor will use 19.75% fuel. There are many others proposing HALEU fuel well above 12%.
ANS
In a letter in Science last Friday (Jan. 31) Lisa Marshall, president of the American Nuclear Society, wrote, “A unilateral approach to establishing a domestic policy contrary to international consensus would impair the ability of the United States and its allies to meet their collective nuclear nonproliferation objectives. It is vitally important than any reevaluation of what constitutes a weapons-useable or direct-use material be developed with international cooperation and in consultation with the IAEA.”
Marshall advised policy makers “to remain optimistic and committed to deploying new advanced reactors, focusing on practical rather than theoretical risks.”
In response to Marshall in the same issue of Science, Kemp and co-authors Lyman and Von Hippel wrote that “it is established by international treaty that nuclear security is the sovereign responsibility of individual states. It is also incumbent on the United States to help inform the development of international standards by carrying out early studies. This has historically been the case, as, for example, when the United States initially established standards to restrict the dissemination of HALEU to quantities less than the amount sufficient to make a nuclear weapon.”
Kemp’s response added, “Marshall also errs in arguing that the international safeguards system maintained by the International Atomic Energy Agency (IAEA) should be assumed sufficient for the widespread use of HALEU. The existing standards were developed in an era when HALEU was used only in small quantities for research reactors. It is important to reevaluate these standards now that power reactors propose to use weapon-relevant quantities and, if necessary, adjust the standards to accommodate this change.”
When NNSA announced its collaboration with the National Academies, MIT’s Kemp said in a news release, “We are happy to see that the NNSA recognizes the need to carry out formal studies of this issue. It will be essential that the National Academies evaluate all advanced fuel types as well as atypical nuclear weapon concepts in their review.”
On Jan. 16, President Trump announced on his “Truth Social” site that he has appointed former one-term Republican member of Congress from New York Brandon Williams to head the NNSA. Williams, 57, joined the Navy in 1991 and served as an office on the nuclear submarine USS Georgia. He left the Navy in 1996 with the rank of lieutenant and then graduated from the Wharton School of the University of Pennsylvania with an MBA.
Williams became a successful investment banker. In 2022 he won election to the House of Representatives from a central New York District and was a Trump supporter. He lost to Democrat John Mannion in 2024.
How Williams will lead NNSA and what his priories or those of Chris Wright, the new energy secretary, will be is an open question.
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