The US military experimented with small reactors in remote locations beginning 1954.1,2 Dr Edwin Lyman, a senior scientist at the Union of Concerned Scientists, summarizes the early experiments:3
"The Army Nuclear Power Program was initiated in 1954, in the heady early days of the atomic power era, to develop ground-based nuclear power plants for military use ‒ a mission distinct from the Navy's submarine nuclear propulsion program already well underway. Over two decades, the US Army built and operated eight small power reactors, ranging from less than one megawatt to ten megawatts of electricity, with limited success. The worst outcome was the 1961 core meltdown and explosion at the SL-1 reactor in Idaho, which killed three operators. Five of the reactors were designed to be portable to some degree, and three were deployed at remote military bases in Greenland, Alaska, and Antarctica. Although these reactors didn't explode, they proved unreliable and expensive to operate. Based on that experience, the program was shut down in 1977."
Efforts to renew the US military's interest in SMRs ‒ including microreactors in the range of 1‒10 MW ‒ have been underway for some time.4 Industry bodies such as the Nuclear Energy Institute have been proactive, and the Pentagon, with the support of Congress, is exploring the potential for the deployment of SMRs at defense installations for power generation, desalinating water and generating hydrogen for fuel. It is potentially a significant market: the Department of Defense manages more than 500 fixed installations and is the single largest energy consumer in the US.
Marc Nichol, the Nuclear Energy Institute's director of new reactor deployment, said in October 2018: "Small reactors are one of the most promising new nuclear technologies to emerge in decades. Energy is important to our national security; it must be reliable and resilient so that it's there when our men and women in uniform need it. Micro-reactors can enhance our capabilities by providing that resilient, 24/7 energy."5
However the plan is improbable and problematic. An article by current and former researchers from Carnegie Mellon University's Department of Engineering and Public Policy, published in the Proceedings of the National Academy of Science in July 2018, discusses the looming problems:6
"Because it is unlikely that further and substantial DOE funding will be dedicated to reinvigorating civilian nuclear power, and because the nuclear enterprise is unlikely to rebound on its own, some have advanced national security arguments to stem and reverse the perceived decline in US standing by assigning this task to the Department of Defense (DoD). Given the current political climate, which supports American primacy in areas of strategic importance, supporters in Congress, think tanks, the Army, and the Navy have floated the possibility of diverting large sums of money through the DoD to catalyze the development and deployment of SMR technologies.
"While we share the fears about the future of nuclear science and nuclear power in the United States, we believe that the proposal to try to address the problem through DoD leadership in development is both unwise and unlikely to succeed. There are several practical challenges. Any SMR that is designed to primarily serve the DoD would likely be too expensive for a commercial utility to deploy. The design specifications upon which the DoD would insist would likely render commercial variants infeasible (because, to minimize or avoid frequent refueling, it would likely need to use fuel that is enriched more than the current operating fleet standard of ∼5% U-235, and perhaps even greater than 20%) and economically uncompetitive in most of today's markets.
"Moreover, SMRs designed to serve a US base would face the same economic challenges as current commercial reactors, and there is no guarantee that a nuclear design would win the day in a competition for US military base power supply. Even siting, a purported advantage of having the military deploy SMRs, would be difficult. The DoD follows state environmental guidelines when they do not compromise the defense mission. The siting of SMRs would likely still become an issue for the DoD in a range of locations, and not just those that reject nuclear power outright. Finally, having the DoD take the lead in development risks creating several large, expensive, "too-big-to-fail" fiefdoms, which would detract from more pressing warfighting needs.
"In addition to the practical challenges, there are compelling normative arguments to be made against relying on the DoD to revivify the nuclear enterprise. These revolve around the role of the US military in American economic and civic life.
"First, the military develops new technologies when they are the only available solution to a problem. Scenarios proposed for military leadership in SMR design and development do not convincingly make the cut when balanced with alternatives, such as power purchase agreements. Second, we endorse the firebreak between the civilian and military nuclear programs because it has substantial normative value. Third, at a time when American civic and political norms rest on precarious ground, using the military to rescue a commercial industry degrades the social fabric from which it derives legitimacy. It also undercuts the DOE by underscoring its failure to enable the development of advanced reactors.
"Most troublingly, adopting this model would amount to an admission of failure on the nuclear industry's part. Defaulting to the national security argument in an effort to salvage the US commercial nuclear industry concedes the failure of the technical and economic arguments in favor of the technology. It also does little to drive commitment from industry that would generate broader deployment. Other options, including long-term power purchase agreements, coordination in human capital development, and research into grid security, constitute avenues for DoD involvement that are more politically credible and economically sound. However, it is unclear that any of these could have more than a modest impact on the development of a domestic SMR industry in the next few decades."
Project Dilithium
In January 2019, the US Department of Defense issued a call for information in support of its interest in acquiring small (1‒10 MW) power reactors for use at forward operating bases.
Edwin Lyman argues that the "inherently safe reactor" sought by the military is a myth:7
"All it really means is that in certain idealized scenarios, a reactor, after shutdown, could be adequately cooled by passive mechanisms, such as convective airflow. But passive safety cannot eliminate every pathway by which the reactor fuel could be damaged and release radioactivity. If a severe accident or sabotage attack were to induce more extreme conditions than the reactor was designed to withstand, all bets are off. How long would passive airflow keep nuclear fuel safely cool if, say, an adversary threw an insulating blanket over a small reactor? Or if the reactor were buried under a pile of debris? Moreover, it is hard to imagine that a direct explosive breach of the reactor core would not result in dispersal of some radioactive contamination. ... At best a release of radioactivity would be a costly disruption, and at worst it would cause immediate harm to personnel, render the base unusable for years, and alienate the host country."
Lyman notes that reactors deployed at forward operating bases or shipped through war zones would be prime targets of the enemy, and if commanders need to expend significant resources to protect them from military strikes, such reactors could become burdens rather than assets.7
Lyman commented on the proliferation risks:7
"The original RFI [request for information] stipulated that the reactor fuel had to be high-assay low-enriched uranium (HALEU), which is uranium enriched to levels above the 5 percent uranium-235 concentration of conventional power reactors, but still below the 20 percent that marks the lower limit for highly enriched uranium (HEU), which is usable in nuclear weapons. Although HALEU is considered highly impractical for direct nuclear weapons use, it has greater proliferation potential than fuel with uranium-235 concentrations below 5% because of the reduced effort needed to enrich it to a weapon-usable level ‒ which is why the international community saw Iran's stockpiling of HALEU as a threat. If the Defense Department goes forward with Project Dilithium, other nations, including US adversaries, may be prompted to start producing HALEU and building their own military power reactors.
"An even more worrisome problem is that the revised RFI issued on January 22 no longer includes the HALEU requirement. That opens the door for reactors fueled with HEU ‒ a major proliferation threat. The Defense Department may be envious of NASA, which is moving forward with development of a tiny HEU-fueled reactor to power deep space missions while turning a blind eye to the proliferation risks. Or it may have decided that the current lack of availability of a sufficient quantity of HALEU for a demonstration reactor would cause an unacceptable delay. Or the omission may simply be a mistake. As of this writing, the contracting officer at Defense has not responded to a request to clarify whether this was an innocuous oversight or a deliberate gesture.
"Given the dubious strategic value, low chance of success, and potential for sparking a HALEU-fueled international arms race, what can explain the Defense Department's renewed interest in small reactors after decades of dormancy? To be sure, Project Dilithium didn't just spring out of nowhere. It is the culmination of a patient, decade-long effort by nuclear lobbyists to interest Defense and its congressional overseers in a costly product ‒ small nuclear reactors ‒ that few in the private sector seem to want. The Pentagon is precisely the savior small nuclear reactor vendors need: deep-pocketed and unbeholden to return-seeking investors. But this coup by the nuclear industry will do little to enhance US national security and could expose fighting forces to undue risk. Hopefully, pragmatists at the Defense Department will realize this and pull the plug on this misguided effort before billions of dollars are wasted on a fruitless search for a reactor as rare as a dilithium crystal."
References:
1. Peter Rejcek, 25 June 2010, 'Powerful Reminder', https://antarcticsun.usap.gov/features/contenthandler.cfm?id=2175
2. Hanne E.F. Nielsen, 23 July 2019, 'Remembering Antarctica's nuclear past with 'Nukey Poo'', https://theconversation.com/remembering-antarcticas-nuclear-past-with-nu...
3. Edwin Lyman, 22 Feb 2019, 'The Pentagon wants to boldly go where no nuclear reactor has gone before. It won't work.', https://thebulletin.org/2019/02/the-pentagon-wants-to-boldly-go-where-no...
4. Dan Yurman, 6 Oct 2018, 'DOD Seeks SMRs for Tactical Readiness at Military Bases', http://neutronbytes.com/2018/10/06/dod-seeks-smrs-for-tactical-readiness...
5. Nuclear Energy Institute, 9 Oct 2018, 'A Big Move Toward Small: Micro-reactors and the Pentagon', https://electricenergyonline.com/article/energy/organisation/nuclear-ene...
6. M. Granger Morgan, Ahmed Abdulla, Michael J. Ford, and Michael Rath, July 2018 'US nuclear power: The vanishing low-carbon wedge', Proceedings of the National Academy of Science, https://www.pnas.org/content/115/28/7184
7. Edwin Lyman, 22 Feb 2019, 'The Pentagon wants to boldly go where no nuclear reactor has gone before. It won't work.', https://thebulletin.org/2019/02/the-pentagon-wants-to-boldly-go-where-no...