US approves large export of bomb-grade uranium

The US Nuclear Regulatory Commission (NRC) has approved the export to Belgium of nuclear fuel assemblies containing 144 kg of weapons-grade uranium, despite the objections of a nuclear nonproliferation activist. The 17 February decision will permit the largest export of US weapons-grade material in five years—enough uranium enriched to 93.3% ²³⁵U to fashion at least five nuclear weapons.

The NRC noted that the exporter, Edlow International, plans to make multiple shipments over time to a Belgian research reactor known as BR2. Each assembly will contain less than 5 kg of highly enriched uranium (HEU). Although the International Atomic Energy Agency defines 25 kg of ²³⁵U as a “significant quantity” sufficient to make a nuclear explosive device, experts say a more sophisticated implosion-type weapon could require as little as 12 kg of weapons-grade uranium.

The export license had been held up by a petition filed with the NRC in August 2016 by Alan Kuperman, a professor at the University of Texas at Austin. Coordinator of the Nuclear Proliferation Prevention Project, Kuperman noted that the center where the BR2 research reactor is located was targeted in the past by Islamic State terrorists. According to news reports , individuals involved in the November 2015 Paris terrorist attacks had surveilled the movements of a senior official at the Belgian Nuclear Research Centre.

In its order, the NRC set the export license to expire in 2023, rather than in 2026 as requested by Edlow. Kuperman says the BR2 could be converted to run on fuels containing low-enriched uranium (LEU)—less than 20% ²³⁵U—in as little as three years if fuel qualification efforts were prioritized.

A uranium silicide fuel has been used successfully in converting many HEU-fueled reactors around the world. Sven Van den Berghe, stakeholder manager for BR2, says that such fuel is being evaluated for the reactor and could be qualified by 2023. But he notes that the type of silicide fuel used in other reactor conversions isn’t viable for BR2. The NRC expects BR2 to be able to switch to an alternative LEU fuel containing molybdenum by around 2028.

Belgian officials last year dropped their request to export the HEU in metal form after Kuperman objected to that plan. Now that the uranium will be transported as part of fuel assemblies, the HEU would need to be removed from its cladding and separated from the aluminum and other materials with which it is alloyed. Van den Berghe calls that process “extremely complicated.” But Kuperman says the extraction would be relatively simple and notes the International Atomic Energy Agency estimates that it could be done in one to three weeks.

The US has been working toward ending international commerce in HEU. The Department of Energy has teamed with other nations to convert most of the research reactors that were fueled with US-produced HEU. In addition to BR2, the US provides HEU to France’s Institut Laue–Langevin, a high-flux neutron source that can’t be converted to LEU fuel with current technology. The US also continues to supply HEU for irradiation targets that produce the medical radioisotope molybdenum-99 at Canadian and European reactors. Conversion to LEU targets is under way.