The US Navy’s Nuclear Proliferation Problem

The proliferation of weapons-grade nuclear materials has long been nightmare fuel for US security professionals, and the effort to stem the flow has been ongoing for decades. In the op-ed below, Prof. Alan Kuperman argues it’s up to lawmakers, and the US Navy, to address a vulnerability of America’s own making.

As the annual defense authorization and spending bills head to congressional floor votes this month, lawmakers have a chance to take the next step in the critical fight against nuclear proliferation — by pushing the US Navy to change the way it powers some of its ships.

A terrorist or rogue state with a nuclear weapon would be a national security nightmare. The most likely path to such a bomb would be for an adversary to divert or steal one of the two required nuclear explosives, plutonium or highly enriched uranium (HEU), from a non-weapons purpose like reactor fuel. That is why the US, for nearly 50 years, has worked to phase out global commerce in these two dangerous materials.

But today the world’s biggest remaining customer for HEU outside of weapons is the Navy, which uses it in reactors to power submarines and aircraft carriers. By contrast, civilian nuclear powerplants use low-enriched uranium (LEU) fuel, which is unsuitable for weapons. The Navy reactors currently use about 100 nuclear bombs’ worth of HEU each year, more than all of the world’s other reactors combined.

This raises three major risks. First, some of the HEU might be stolen from a fuel factory to make a nuclear weapon, as may have occurred in the 1960s (reportedly by an ally, Israel, fortunately). Second, rogue states could claim that they too need HEU for their navies, as Iran did to justify its recent start of HEU production. Third, since the Navy is running out of HEU, the Energy Department has said it will need to restart production of nuclear weapons-grade uranium for the first time since 1992 – which could devastate U.S. arms control and nonproliferation efforts around the world.

Fortunately, there is a solution to all of these problems: The Navy could develop new reactors to run on LEU. France already has converted its nuclear navy from HEU to LEU, and China’s submarines also use LEU fuel.

In 2016, both the Navy and then-President Barack Obama praised the idea of developing LEU fuel for naval reactors. The White House declared that “consistent with its national security requirements and in recognition of the nonproliferation benefits to minimizing the use of highly enriched uranium globally, the United States values investigations into the viability of using low-enriched uranium in its naval reactors.”

The Naval Reactors office stated in a report to Congress that successful development of an “advanced fuel system could allow use of LEU fuel with minimized impact on reactor lifetime, size, and ship costs.”

However, annual budget requests never have included the research and development program, leaving it vulnerable during the legislative process, especially this year. From FY2016 to 2021, Congress did authorize and appropriate annual funding, increasing gradually from $5 to $20 million. This year, however, only a House appropriation bill has included the needed $20 million. There is no funding in the counterpart bill approved by the Senate Appropriations committee, nor authorization in the defense bills approved by the Armed Services committees.

Opposition to the program is not due to any insurmountable technical or financial hurdles. A quarter-century ago, the Navy had claimed that the cost of converting to LEU fuel would be unacceptably high due to requiring much larger reactors.  However, subsequent development of higher-density LEU fuel means that today the reactors would need to be only marginally bigger — or the same size as existing reactors if the Navy opted for refueling during the life of the ship.

The Naval Reactors office itself stated in 2016 that funding the required research “might enable an aircraft carrier reactor fueled with LEU in the 2040’s… .” As for submarines, even proponents concede that conversion should await the design of new classes of ships, to facilitate the slightly larger reactors or refueling hatches required for LEU fuel.

The real obstacle is that the Navy simply does not view supporting this U.S. nonproliferation policy as its responsibility. Or, as the Secretary of the Navy put it in 2018, “A program to pursue R&D of an LEU advanced fuel system would compete for necessary resources against all other NNSA and Department of Defense priorities as part of a future budget request.”

Navy engineers are more than capable of developing LEU fuel that would preserve the capacity of our warships, but their bosses feel no urgency to switch from HEU fuel. That is short-sighted. If a rogue state or terrorist acquires nuclear weapons, it will be a problem for all Americans, including the U.S. Navy.

Since the Biden Administration failed to confront the Navy on this issue in its first budget request, Congress must step up again.

In the House, Rep. James Langevin, D-R.I., the second ranking Democrat on the Armed Services committee, has spearheaded the program from the start, along with Rep. Bill Foster, D-Ill., the only Ph.D. physicist in Congress. Monday, they submitted an amendment to restore the program’s authorization when the defense bill reaches the House floor next week.

At a hearing this past June, Langevin asked the head of the National Nuclear Security Administration, “For the record, will NNSA continue to support efforts to study the viability of this critical non-proliferation effort should additional funding be made available?” The NNSA’s then-acting Administrator, Charles Verdon, replied, “We are committed to continuing to look at that,” which suggests the administration could welcome such funding despite not having requested it.

In the Senate, Dianne Feinstein, D-Calif., chairs the energy appropriations subcommittee and has supported the program for six years, so its omission from this year’s bill might just be an oversight arising from the extremely compressed legislative calendar. Sen. Ed Markey, D-Mass., is Congress’s staunchest advocate of phasing out HEU fuel and could offer floor amendments to restore the authorization and appropriation.

If the program dies, however, Iran and other rogue states would have more justification to produce HEU, which they could then divert to nuclear weapons. Meanwhile, terrorists could target the U.S. civilian facilities that produce HEU fuel for the Navy, needing to get lucky only once. To avert such nightmares, Congress must save the program this year, and the Biden administration should then codify it as a program of record, so the Navy can finally join U.S. efforts to stop the spread of the bomb.

Alan J. Kuperman is Associate Professor, and Coordinator of the Nuclear Proliferation Prevention Project (NPPP.org), at the LBJ School of Public Affairs, University of Texas at Austin.