U.S. Department of Defense (DOD) is increasingly interested in the potential of Small modular reactors (SMRs) defined as nuclear reactors generally 300MWe equivalent or less. DOD’s attention to small reactors stems mainly from two critical vulnerabilities it has identified in its infrastructure and operations: the dependence of U.S. military bases on the fragile civilian electrical grid, and the challenge of safely and reliably supplying energy to troops in forward operating locations.
SMRs have generated global interest, and potential future applications are a subject of international research directives. Their are around 50 different SMR designs worldwide according to the IAEA. Project proposals include use of SMRs for desalination, process heat generation, biofuel conversion and military base installations. Furthermore, SMR safety systems reduce threats to public health; decrease the global stockpile of weapons-grade material and radioactive waste; and provide critical infrastructure support on military installations worldwide.
The U.S. Army built the world’s first floating reactor, the SS Sturgis MH-1A, a 10-megawatt converted Liberty Ship, in 1967. It supplied power to the Panama Canal Zone from 1968 to 1975, before being defueled in 1977. Decades later, in 2010, Russia launched the 21,000-ton, 70 megawatt Akademik Lomonosov, which is expected to deploy in 2018 or 2019 to Vilyuchinsk, on the remote Kamchatka Peninsula.
Russia is in advanced stages of building the world’s first “floating” nuclear power plant (FNPP) for installation in remote areas and hopes FNPP technology will also interest South Asian countries like India. While the plant is already being tested, construction of the dock has begun on the Arctic coast in Russia’s Far East. Any industrial project in the Artic would require tons of electric energy, and this is why Russia is also developing floating nuclear power plants. Russian company Rosenergoatom (part of Rosatom state-owned corporation) launched a project in 2006 to build floating NPPs in regions with limited energy capabilities.
China has said it will develop floating nuclear power plants on a priority basis in the South China Sea as it seeks to beef up electricity supply to the islands in the disputed maritime region. The floating nuclear reactors could also power Chinese underwater mining operations, in which China has already invested heavily, and deepwater logistical bases for naval usage.
The new generation SMR is designed with modular technology using module factory fabrication, pursuing economies of series production and short construction times. 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.
China’s marine nuclear power platform to start by 2020 in S.China Sea
A shipbuilding firm in Central China’s Hubei Province has announced it is set to start construction on a marine nuclear power platform which is designed to supply power for the country’s offshore oil drilling platforms and islands. The technical design has been finalized, and the project is moving to the construction phase, local media the Hubei Daily reported. China National Nuclear Power (CNNP) is partnering with Chinese shipyards and electric machinery companies to develop a $150 million project. China has had some overseas success already with its Hualong reactor, with Pakistan currently building a plant using the technology.
The primary focus of China’s offshore nuclear platforms – reportedly to be commissioned before 2020 – will be for civil use on islands in waters such as the South China Sea, and as the technology matures, it could be applied to military nuclear vessels, Chinese analysts said.
The platforms have two modes – floating and submersible, and the platforms will focus on solving power supply issues in the Xisha Islands and other islands in the South China Sea where infrastructure construction is underway, and urban agglomerations after that, Song Zhongping, a Beijing-based military expert and also a TV commentator told the Global Times.
China National Nuclear Corporation (CNNC) is set to launch a small modular reactor (SMR) dubbed the “Nimble Dragon” with a pilot plant on the island province of Hainan, according to company officials. CNNC designed the Linglong, or “Nimble Dragon” to complement its larger Hualong or “China Dragon” reactor and has been in discussions with Pakistan, Iran, Britain, Indonesia, Mongolia, Brazil, Egypt and Canada as potential partners. China National Nuclear Corporation (CNNC) has said that China is expected to build 20 floating nuclear power stations in the future, which will significantly beef up the power and water supplies on the South China Sea islands, another official daily Global Times reported. Sun Qin, former chairman of the National Nuclear Corporation, said in March 2016 that the facility is scheduled to be put into operation in 2019.
China has said it will develop floating nuclear power plants on a priority basis in the South China Sea as it seeks to beef up electricity supply to the islands in the disputed maritime region. China will prioritise the development of a floating nuclear power platform in the coming five years, in an effort to provide stable power to offshore projects and promote ocean gas exploitation, Wang Yiren, vice director of the State Administration of Science, Technology and Industry for National Defence. Wang told Science and Technology Daily that Chinese authorities have already carried out research on relevant core technologies as well as the standardisation of maritime nuclear power plants. The floating nuclear reactors could also power Chinese underwater mining operations, in which China has already invested heavily, and deepwater logistical bases for naval usage.
“Floating power stations are less susceptible to natural disasters. In an emergency, the station could pump seawater into a boat to prevent core melting. Besides, the platform is small and can be dragged to a suitable place for maintenance,” reported in February, quoting an expert.
China General Nuclear, the company behind the new project, stresses the flexible nature of a ship-based nuclear reactor. “The 200 MWt (60 MWe) reactor has been developed for the supply of electricity, heat and desalination and could be used on islands or in coastal areas, or for offshore oil and gas exploration.” Other potential uses could be for new, large-scale industrial installations and flexible emergency power to regions in the event of natural disasters such as earthquakes or tsunamis
Zhang Jinlin, an academician at the Chinese Academy of Engineering and an expert at the CSIC 719 Research Institute, told that the platform is a typical civilian-military integration project, as its design fully takes civil demands into consideration, as well as tackling issues including safety, radiation protection and waste processing.
The nuclear reactor-related technology, when successfully reduced in size, could be later applied to the country’s military vessels, including nuclear-powered aircraft carriers or next generation nuclear submarines, Song said.
Russia building world’s first ‘floating’ nuclear power plant: Officials confirm construction ‘at closing stage
Russia’s ‘Project 20870’ involves placing two nuclear reactors on 140-meter long, 30-meter wide barges. The plan would use these nuclear barges’ 300MWt (thermal energy production) or 70 MWe (electrical energy production) to power remote cities and industrial sites throughout the Russian Arctic. The cost of the floating plant is estimated at around 30 billion rubles (US$480 million), according to Sergey Zavyalov, head of the plant construction.
The construction works on the dock, which will host the floating nuclear power plant ‘Akademik Lomonosov’, have started and completed by 2019. The severity of weather conditions (in winter, the temperature drops down to minus 60 degrees Celcius) obliging, the onshore facilities will be forced to endure ice impact and squalling winds.
The 21,000-tons unit will have two Russian-designed KLT-40S reactors, low-enriched uranium-fueled reactors used in some of Russia’s icebreakers, and two steam-driven turbines. One unit is able to provide enough electricity to power a city of 200,000 people. It can also produce 300 megawatt of heat that can be transferred onshore, equal to saving some 200,000 tons of coal every year.
The FPU is not self-propelled and must be towed to the location of operation. It is a barge consisting of three decks and 10 compartments. Apart from reactors, it is equipped with storage facilities for fresh and spent nuclear fuel, as well as liquid and solid nuclear waste. Experts have praised floating power plants for being secure from earthquakes and tsunamis, as well as from meltdown threats, as the reactor’s active zone is underwater.
“Reactor units are small and self-contained. They are nothing like those installed at the Chernobyl nuclear power station, of course. A scenario like that at the Fukushima power plant is also excluded,” Professor Georgy Tikhomirov of the Moscow Engineering Physics Institute recently told EFE news agency.“The advantage of the floating nuclear power plant is that it can be moored almost anywhere where there is a power line,” Tikhomirov said.
Akademik Lomonosov’ is to become the first of a proposed fleet of floating nuclear power plants that can provide heat and energy to the country’s remote regions, and assist in natural resource extraction. Russia also plans to lease the plants to other countries, where they will be used for electricity production and water desalination, as the facility could be converted into a desalination plant with production capacity of some 240,000 cubic meters of fresh water per day.
Pavel Ipatov, Deputy CEO (Special Projects) in Russia’s state atomic energy corporation Rosatom, told IANS in an e-mail interview from Moscow that an FNPP is basically a mobile, low-capacity reactor unit operable in remote areas isolated from the main power distribution system, or in places hard to access by land.
“FNPPs are designed to maintain both uninterruptible power and plentiful desalinated water supply in remote areas,” he said. The Russian explained that floating units are components constructed for transport by sea or river to areas that are otherwise inaccessible or difficult to reach by land.
“The plant is constructed as a non-self propelled vessel to be towed by sea or river to the operation site. Its mobility will make it possible to relocate it from one site to another, if necessary,” he said. “The first floating NPP is to operate in Russia’s extreme northeastern region of Chukotka, where there is plenty of oil and gas exploration, gold mining and other mineral resource enterprises,” he added.
The FNPP has an electric capacity of 70 MW and is equipped with two reactors of 150 MW thermal capacity each. “A vessel like that can provide electric supply to a city of 200,000 and heat supply to a million-plus city,” Ipatov said. An FNPP’s operational life span ranges from 35 to 40 years.
In line with conventional onshore nuclear plants that are often equipped with desalination units for freshwater, the FNPP will have a desalination unit producing up to 240 cubic metres of water per hour. Besides, as regards safety, the Russian said that FNPPs would be governed by the same advanced safety parameters put in place after the Fukushima disaster in Japan in 2011.
“We see significant potential in Southeast Asia and other regions of the world. Memorandums of cooperation on floating nuclear power plants projects have been signed with China and Indonesia,” he said.
Iceberg Design Bureau won the tender of the Ministry of Industry and Trade for project development of a multipurpose nuclear maintenance ship. The ship is needed for servicing of Project 22220 icebreakers and the floating nuclear power plant Akademik Lomonosov. Baltiysky Zavod shipyard keeps on building of Project 22220 nuclear-powered icebreakers Arktika, Sibir and Ural. The ships are expected to join Atomflot in 2019, 2021 and 2022 respectively.
US Navy eyes small modular reactors for its Bases
Navy had better success with developing nuclear power for its aircraft carriers and submarines. But these have quite different requirements from today’s SMR proposals. A submarine reactor is designed to operate under stressful conditions—to provide a burst of power when the vessel is accelerating, for example. And unlike civilian power plants, naval nuclear reactors don’t have to compete economically with other sources of power production. Their overwhelming advantage is that they enable a submarine to remain at sea for long periods of time without refueling.
Navy secretary Ray Mabus says there’s another alternative his department’s hasn’t explored yet: nuclear, and its time may have come. While nearly a fifth of the Navy’s ships run on nuclear power, the only land-based nuclear reactors the service operates are for training purposes. But Mabus said he wants to explore the concept of installing small, modular nuclear reactors on bases to continue their push toward independence from off-base energy.
Rather than the large, utility-scale nuclear plants currently in use by civilian power companies, Mabus said he envisions a system of small, “distributed” nuclear generators networked together via a microgrid on a given base.
“With some of the new technology that’s coming along, it’s much safer, it produces far less residue and nuclear waste, and it is an option that I think we should explore,” he said at the Council on Foreign Relations in New York. “They are safer than traditional nuclear plants because of automated safety features and containment systems that are entirely underground, and cheaper because they can be fabricated in factories and quickly assembled at the sites where they’ll be used.”
Small Nuclear Reactors
The major disadvantage of nuclear power compared with other types of electricity generation is that nuclear power is expensive. According to a 2014 report by the Wall Street advisory firm Lazard, the cost of generating a megawatt-hour of electricity from a new nuclear reactor (without considering government subsidies, including those for liability for severe accidents) is between US $92 and $132. Compare that with $61 to $87 for a natural-gas combined-cycle plant, $37 to $81 for wind turbines, and $72 to $86 for utility-scale solar. Nuclear’s high costs result directly from the very high costs of building a reactor—estimated by Lazard at $5.4 million to $8.3 million for each.
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. As Suid writes, the Army concluded “that the development of complex, compact nuclear plants of advanced design was expensive and time consuming…that the costs of developing and producing such plants are in fact so high that they can be justified only if the reactor has a unique capability and fills a clearly defined objective backed by the Department of Defense…[and that] the Army and the Pentagon had to be prepared to furnish financial support commensurate with the AEC’s [U.S. Atomic Energy Commission’s] development effort on the nuclear side.”
SMRs provide a number of benefits compared to the commercialized light water reactors, or LWRs, some of which are of particular interest to the Department of Defense. SMR designs for military base applications, such as the FliBe Energy’s Liquid Fluoride Thorium Reactor, provide a mobile and reliable avenue for on-site electrical power generation and desalination.
Storms, blown transformers or sabotage can disable power grids, which is of concern to military installations connected to them. In isolated areas or military installations, the loss of power to site infrastructure can result in significant financial loss or loss of life.
Employing SMR technology on military bases will also allow for access to clean water, which is a largely unavailable resource across the globe. The U.S. Navy nuclear-powered aircraft carriers desalinate an estimated 400,000 gallons per day
SMRs use technology that establishes dynamic safety; enhances nuclear waste management protocols that benefit nonproliferation; and generates on-site electricity and potable water on military installations.
One major advantage of SMRs is their implementation of advanced safety features. SMRs employ passive safety systems that allow natural coolant circulation pathways to control reactor conditions. Passive safety requires that indefinite self-cooling and safe shutdown is possible without operator input, electrical power and additional coolant input.
SMRs are also significantly more compact than commercial LWRs. This reduces overall complexity and reduces potential modes of reactor control system failure. The Toshiba Super-Safe, Small and Simple and the Lawrence Livermore National Laboratory Small Secure Transportable Autonomous Reactor utilize a tamper-proof system that includes remote shutdown, sealed reactor core and autonomous operation. These safety features minimize on-site personnel and allow for global SMR usage because they assist in securing the reactor core against violent non-state actors and terrorist groups seeking to gain access to nuclear material.
Nonproliferation and Waste Management
The generation of radioactive waste, such as Uranium-238 and Plutonium-239, occurs over the course of a commercial LWR fuel cycle. The production and storage of these materials is a threat to public health and inhibits nuclear armistice. Pu-239 is the most common material used in nuclear weaponry. The reduction of Pu-239 stockpiles aids the movement for nonproliferation of the global nuclear arsenal by decreasing the amount of material available for weapons production.
SMR designs powered by spent nuclear fuel are an international research focus. Developments based in the U.S. include SMR models such as the General Atomics Energy Multiplier Module; the X-energy 100; and the General Electric Hitachi Power Reactor Innovative Small Module.
The World Nuclear Association lists the features of an SMR, including:
- Small power and compact architecture and usually (at least for nuclear steam supply system and associated safety systems) employment of passive concepts. Therefore there is less reliance on active safety systems and additional pumps, as well as AC power for accident mitigation.
- The compact architecture enables modularity of fabrication (in-factory), which can also facilitate implementation of higher quality standards.
- Lower power leading to reduction of the source term as well as smaller radioactive inventory in a reactor (smaller reactors).
- Potential for sub-grade (underground or underwater) location of the reactor unit providing more protection from natural (e.g. seismic or tsunami according to the location) or man-made (e.g. aircraft impact) hazards.
- The modular design and small size lends itself to having multiple units on the same site.
- Lower requirement for access to cooling water – therefore suitable for remote regions and for specic applications such as mining or desalination.
- Ability to remove reactor module or in-situ decommissioning at the end of the lifetime.
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.
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. Greenpeace has voiced concern about what effect massive storms could have on ocean-based nuclear reactors.
Others worry ocean-based reactors would be more susceptible to terrorist attacks and increased proliferation risks. Operating nuclear reactors in an Arctic climate is complicated to say the least, and another concern is that barges like those used in the Russian project might not be as protected from earthquake or tsunamis as reactors further out at sea.