The Complex Policy Questions Raised by Nuclear Energy’s Role in the Future of Warfare, Just Security  by Alex Gilbert, Morgan Bazilian and Julia Nesheiwat, March 16, 2020  The United States military, as well as other militaries around the world, are racing to develop high-energy weapons—lasers, high-powered microwaves, and electromagnetic rail guns—in order to compete with near-peer competitors on the next generation of military technologies. But the electricity to power these systems will need to derive from somewhere, and so military planners are eyeing a new generation of energy-dense nuclear reactors, despite potential policy and legal challenges to doing so…….. The Army is considering mobile nuclear power plants, in part to drive high-energy weapons, an idea one retired three-star hailed as a potential logistics revolution. And should the U.S. build space-based lasers for missile defense, nuclear energy may be the only way to provide the needed megawatts.

All this raises key policy concerns in relation to international law, rules of engagement, and the laws of warfare.

Basing, or even deploying, nuclear reactors in the territorial waters or land of an overseas ally requires the permission of the host government, which may be averse to expanding nuclear power as in the case of major bases like Yokosuka, Japan. Diego Garcia, an island in the Indian Ocean, provides another challenging case as the ongoing territorial dispute between the United Kingdom and Mauritius threatens the U.S. base there, and a nuclear plant would only complicate the existing dispute.

The U.S. Navy already faces constraints on where their nuclear-powered ships can visit. Floating nuclear power plants, like those developed by Russia and China, face similar concerns if they transit foreign waters or, in the case of the South China Sea, are stationed in disputed territories. Similarly, mobile reactors, like those considered by the U.S. Army, would likely be transported by air, requiring permission of all overflight countries.

Beyond basing, a critical question is whether the U.S. military would own and operate these new reactors, as the Navy currently does, or whether they would pursue commercial alternatives, as the Army is considering. The U.S. Army report on mobile reactors noted that, with either government or commercial ownership, there are concerns about international rules and licensing that present potential barriers to deployment. In some cases, potential host countries do not even have nuclear regulatory agencies. Further, commercial ownership raises liability concerns, both in the case of a military incident or an accident. International nuclear liability treaties are not well harmonized between the U.S. and most of its allies, especially when it comes to the unique concerns of transportable reactors.

Using nuclear power for high-energy weapons also creates targeting dilemmas for the U.S. and foreign militaries. High-energy weapons and their support infrastructure, including reactors, may be initial targets in a conflict. The social, environmental, and reputational impacts of damaging a nuclear reactor, particularly on a country’s home territory, or with effects on a third country, could lead to conflict escalation and international condemnation…….

Nuclear-powered laser satellites could aggravate concerns about nuclear arms controls as such systems could be used for anti-ballistic missile or anti-satellite applications. While the Outer Space Treaty prohibits weapons of mass destruction in orbit, it does not prohibit other types of weaponry. During the Cold War, Soviet military space reactors raised calls for bans on space nuclear power, particularly after one accidentally crashed in Canada.   Recent calls for space arms control have been unsuccessful. As with terrestrial nuclear-powered lasers, the unique role of laser satellites would make them early targets in any major power conflict, leading to risks of collateral damage from radioactive and dangerous space debris, as occurred after the accidental 2009 collision involving a decommissioned Soviet nuclear satellite..