|Fig. 1: The NuScale Power Module is one example of a small modular reactor that features a self-contained design and passive cooling. (Source: Wikimedia Commons)|
As global demand for electricity increases, and efforts to reduce carbon emissions are strengthened, nuclear power is repeatedly put forward as a viable option for energy generation. While the 2011 disaster at the Fukushima Daiichi nuclear plant in Japan has fed arguments against nuclear energy, many countries are pushing new development in nuclear energy technology.  Since the 1970s, nuclear plants have been built as large as possible - usually in the range of 1000-1400 megawatts of electrical output power (MWe) - but now many new designs propose the use of smaller nuclear reactors, with output less than 300 MWe.  While these designs are promising, they are untested and present new proliferation risks. There are many concerns about using small reactors for energy generation, but the unique needs of the military make their use for military purposes more likely. These small reactors could be installed on military installations and forward operating bases to increase energy security, reduce dependence on fuel convoys, and ensure continued operations at home and abroad.
The wide range of designs for small nuclear reactors makes it hard to generalize their technology, but there are several overarching themes among them. These include flexibility, simplification, passive cooling and safety features, and lower capital costs. [2-4] The flexibility of these reactors often derives from the modular nature of their designs. Collectively called small modular reactors (SMRs), these can be added incrementally as load increases, with each additional reactor being theoretically easier and cheaper to build.  The main safety features of new designs include gravity-enabled cooling, compactness, fewer coolant pipes, and underground installation, as shown by an example design in Fig. 1. [2-4]
While the benefits of small nuclear reactors are promising, there remain many unsolved disadvantages. From a technical standpoint, new small-scale reactor designs are immature. The current fleet of large-scale light water reactors has demonstrated decades of successful operation at very high standards, and new small reactor designs will need to undergo rigorous testing to prove their worth. New control and safety systems, non-traditional components, and unconventional fuel and cooling materials are examples of design features that will take many years to develop to commercial viability. [2,4]
Other challenges to small nuclear reactors are non-technical. First, too many competing designs in the market create confusion and delay the ability to achieve the standardization that will be necessary for widespread adoption. Another challenge is the bias towards large nuclear plants to achieve economies of scale. [2,3] And perhaps most important politically, the widespread construction of small nuclear reactors means that there are more targets for terrorist attacks and increased proliferation risks due to the decentralized waste storage. 
The U.S. Department of Defense (DOD) is the largest organizational user of petroleum in the world.  In 2011, the DOD consumed about 117 million barrels of oil and paid $17 billion for it.  Because of these immense costs - financial and other - of this consumption, the DOD recognizes that it needs to dramatically change how it generates and consumes energy.  One potential solution to this problem is the adoption of small nuclear reactors for military bases. This change in energy use can eliminate risks to fuel convoys, increase base energy efficiency, bolster operational capabilities, decrease carbon emissions, and reduce other energy-related vulnerabilities. 
The U.S. military has a strong historical involvement with nuclear power that strengthens its case for re-adopting it. The U.S. Navy launched the world's first nuclear powered submarine in 1954, and since then the Navy has operated hundreds of nuclear submarines successfully.  Also, the U.S. Army Corps of Engineers operated an experimental nuclear energy program from 1954 to 1979. The Army's small nuclear reactors generated power for remote installations in Greenland, Antarctica, Alaska, and other locations.  This program ended in 1979 due to a number of factors, including the accident at Three Mile Island, cheap fossil fuel prices, and an overall waning of national interest in nuclear power. 
|Fig. 2: The U.S. military's Forward Operating Base Gardez is located in the Paktia province of Afghanistan. (Source: Wikimedia Commons)|
In the U.S., military installations are almost always dependent on the civilian electrical grid for their power.  This patchwork grid, built over decades across the country, is aging, near its capacity limit, and outside of DOD control. In addition, it is increasingly susceptible to kinetic or cyber attack. One report sponsored by the Department of Homeland Security claims that a coordinated cyber attack on the grid could result in a weeks-long blackout across one third of the country.  In the event of such an attack, many military bases could lose critical intelligence, communications, and logistics capabilities. One method to mitigate this risk is to construct microgrids on military installations that would island them from the civilian electric grid. Because most bases have relatively light power demands, a small nuclear reactor located on base could provide all of its required power. 
When U.S. military forces operate abroad, they often cannot rely on civilian power grids. In the deserts of Iraq and Afghanistan, for example, diesel generators power the electricity and cooling loads for forward operating bases, such as the one shown in Fig. 2. In 2010, it was estimated that the fully burdened cost of fuel for U.S. forces in Iraq and Afghanistan was as much as $45 per gallon, depending on the delivery method and force protection requirements.  Another cost is more startling: from 2002 to 2010, about 1,000 Americans were killed on fuel-related missions in Iraq and Afghanistan.  The DOD has ongoing programs to improve insulation in buildings and tents, promote energy efficiency, and increase the use of renewable energy at forward operating bases, but nuclear power might be a viable option to replace the diesel generators entirely to provide reliable and constant energy. [3,7]
The U.S. DOD recognizes that it has a clear obligation to change how it generates and uses energy. Desires for environmental responsibility, energy security, and sustainability all pressure the DOD to push away from its reliance on fossil fuels, and the utilization of small nuclear reactors is one path forward. Military installations that are connected to the civilian electrical grid are increasingly vulnerable to power outages due to natural disasters or attack, and current backup energy sources are inadequate. Abroad, the massive amounts of time, money, and manpower spent on petroleum procurement for forward operations is unsustainable, and it puts too many lives at risk. New designs for small nuclear reactors are promising, but they are untested and face many hurdles before they reach commercial viability. If the DOD pushes for military application of these designs, it might be able to prove the effectiveness of these systems ahead of civilian markets. This report does not address the potential downsides of deploying a nuclear reactor in a combat zone - which are many - but instead hopes to present small nuclear reactors for military bases as an option worth exploring.
© Alexander Yachanin. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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 R. Andres and H. Breetz, "Small Nuclear Reactors for Military Installations: Capabilities, Costs, and Technological Implications," National Defense University, Strategic Forum. No. 262, February 2011.
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 M. King, L. Huntzinger, and T. Nguyen, "Feasibility of Nuclear Power on U.S. Military Installations," Center for Naval Analyses, March 2011.
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