The military potential of low-enriched uranium fuel poses a greater threat than publicly acknowledged

An analysis published in the journal Science found that, contrary to widely held assumption, high-grade low-enriched uranium (HALEU) currently produced under federal subsidies to fuel the next generation of small nuclear reactors can be used directly to make nuclear weapons, and presents therefore greater terrorism. and nuclear proliferation than those publicly recognized by the federal government and industry.

“If HALEU became a standard reactor fuel without appropriate restrictions determined by an interagency safety review, other countries would be able to obtain, produce, and process weapons-usable HALEU with impunity, thereby eliminating the sharp distinction between peaceful and non-peaceful nuclear programs.” according to analysis by five of the world's leading academic and independent proliferation experts.

“Such countries would be only days away from a bomb, giving the international community no warning of imminent nuclear proliferation and virtually no opportunity to prevent it.”

The document calls for additional measures to mitigate this risk as the United States and other countries continue the international deployment of reactors powered by HALEU fuel. “Given the stakes, we recommend that the U.S. Congress direct DOE's National Nuclear Security Administration to commission a new study of HALEU proliferation and security risks by experts from U.S. weapons laboratories.”

Current commercial reactor fuels do not rely on HALEU, which is enriched to between 10 and 20 percent uranium-235, but generally use uranium enriched to less than 5 percent. At these levels, the fuel cannot sustain an explosive chain reaction, which has prevented countries or terrorists from reusing commercial reactor fuel to make weapons.

However, for technical reasons, many of the nuclear reactor designs engineers want to build today would use HALEU. Since HALEU is below the 20% lower enrichment limit defining highly enriched uranium (HEU), believed to be directly usable in nuclear weapons, the development of these reactors has not raised major problems of proliferation.

But by examining the information available in the open literature to analyze the quantities and levels of HALEU enrichment that new reactors would use, the study authors Science The paper concluded that HALEU containing more than about 12% uranium-235 could be used to make practical weapons with yields comparable to those of the bombs that destroyed Hiroshima and Nagasaki. Many proposed reactors could contain enough HALEU to make a nuclear weapon and would thus pose serious security risks, according to the article.

These risks increase because, although the amount of HALEU used commercially today is relatively small, the federal government actively encourages the use of HALEU and funds its production.

The U.S. Department of Energy is covering half the cost of deploying two demonstration nuclear power plants that plan to use multi-ton quantities of HALEU fuel, including the “Natrium” fast reactor that TerraPower, a company founded by Bill Gates, plans to build Kemmerer, Wyoming.

Earlier this year, the federal government allocated $2.7 billion to subsidize enriched uranium production, including HALEU, to power these and other reactor projects that are being considered for a range of applications , including powering data centers and oil and gas operations. Other countries are following suit.

Many HALEU-powered reactors would use uranium enriched just below the 20% limit, which poses the highest risk. The researchers suggest that “a reasonable balance between risks and benefits would be achieved if enrichment of power reactor fuels were limited to less than 10 to 12 percent uranium-235,” which would allow many models of reactors to move forward with modest economic consequences. .

However, if higher enrichments continue to be used, the authors recommend that security standards to protect HALEU against theft be increased to the levels that apply to HEU and plutonium, weapons-usable materials.

Provided by the Union of Concerned Scientists