Emerging Tech Focus: Small Modular Nuclear Reactors
ASHTON MEHTA, MANU RAMINENI, SREYA GANDRA
Over 124 countries worldwide have set carbon neutrality goals to reach by 2050, and an even greater number, including countries like Ukraine and China, have made promises to achieve carbon neutrality by 2060. Even though this may seem like a long time into the future, when transitioning to a carbon neutral country will no longer be meaningful enough to reverse the abundance of existing greenhouse gasses, the reality is that this transition is a process that will require decades of progress towards actively solidifying those goals. This is why efforts to enact policies and integrate technology targeting sustainability goals are of paramount importance today and not five or ten years into the future.
Although it may be some time before they are deeply integrated within the world’s infrastructure, a considerable amount of progress has already been made in developing these technologies. Sourcing energy is at the root of most carbon emissions, so there have been heavy investments into developing technologies aimed at reducing carbon emissions in popular energy producing methods such as carbon capture in coal plants. On the flip side, there also has been heavy investments into making existing renewable energy infrastructure more efficient and affordable. New photovoltaic configurations and cheaper materials costs will ensure the ubiquity of solar power in the upcoming decade. Similarly, the advancement of nuclear power will likely be led by a technology called Small Modular Nuclear Reactors (SMRs).
Even though it provides an alternative to conventional fossil fuels, nuclear power can be a particularly polarizing topic because of its costs and byproducts. Particularly, the topic has been largely popularized because of infamous disasters such as the nuclear meltdowns in Chernobyl and Fukushima in 1986 and 2011, respectively. In the case of the latter, a nuclear meltdown released considerable amounts of radioactive waste into the surrounding environment, even with countless safety measures in place. The dangers associated with these plants can have potentially catastrophic magnitude. However, comparing the effects to other forms of energy production, it has been found that nuclear power actually results in less deaths per kilowatt-hour than coal, natural gas, and wind, making it far from the most deadly renewable energy source.
But fatalities alone don’t paint the entire picture for the effects of conventional nuclear reactors. Nuclear reactors produce radioactive waste, as it is inherent in its design. Unused uranium and intermediate products including plutonium and curium are highly radioactive byproducts that pose increasingly concerning storage concerns for the near future. Even today, many nuclear plants still cannot ensure that radioactive iodine isotopes with long half-lives will not escape into the surrounding environment.
Nuclear reactors are indeed a promising start for a reliable source of renewable energy production but it is no doubt far from ideal. Although new generations of conventional nuclear reactors offer small improvements in mitigating risks of meltdown and increasing the integrity of radioactive waste storage, it is likely that SMRs will be the future of this segment because of its superiority in design and sustainability. However, limitations such as lack of development hinder it from becoming widespread in the time being.
WHAT ARE SMALL MODULAR NUCLEAR REACTORS
Small modular nuclear reactors (SMRs or SMRs) are distinguished from typical nuclear reactors in several different ways including efficiency, modularity, and power capacity, hence the name. Conventional nuclear reactors are well-known for their imposing size and famous structure. Commonly seen towering over the Earth’s surface, even from miles away, it is evident that it takes years of design, planning, and construction to even get the structure to an operational state. The level of financial investment is simply unfeasible for areas that are not economically stable.
The efficiency of a SMR is largely a result of its relatively small size. Inherent in its design, SMRs only have about one third of the power generating capacity of traditional reactors, totaling to about 300 Mw. From a production standpoint, SMRs are significantly cheaper to produce than traditional reactors. SMRs are estimated to cost less than 15- 40% of that of conventional reactors. From another perspective, this feature is what allows SMRs to be “coupled” with other renewable and non-renewable energy sources, optimizing “grid security and stability.” In addition to its ability to be sited in relatively remote locations, these collective benefits facilitate adoption in less urbanized areas, bringing alternative energy to a more rural population.
The modularity feature of SMRs comes from the fact that each component in the system itself can be manufactured in a separate factory and then shipped to the final location for implementation. Conventional nuclear plants are constructed such that a majority of the work is required to be completed on site for the assembly of individual components and the integration of those components into a whole. Logically, the amount of time and capital investment needed to complete construction is a fraction compared to its conventional counterpart. Some of the secondary benefits that arise from this design choice is the decreased cost in design and increased level of safety because of the simplicity. As more power generation capacity is required, the modularity of the system allows components to be added at minimal cost.
However, some of these key advantages are also interpreted as downsides by traditionalists in the space. For both manufacturers and operators, the small size of SMRs discourages production because of the commercial disadvantage of smaller output as compared to its conventional counterpart. In addition, for a single operator, it is logically more difficult to maintain many different SMRs instead of one large nuclear reactor.
COMPETITIVE LANDSCAPE & KEY PLAYERS
The following is a list of IAEA-certified small modular reactors in current development by independent companies and state-owned enterprises across the globe. Outside of these efforts, there exists a litany of efforts which are lacking certification by the International Atomic Energy Agency (IAEA).
ACP 100
It should be noted that China has historically led the SMR revolution, not only being the first country to create an operational reactor connected to the energy grid, but also given their development of the ACP 100, which was the first small modular reactor to receive certification from the IAEA in 2016. Construction has began last year and is expected to be completed soon.
BWRX-300
The United States recently created a scaled-down version of the ESBWR, a boiled-water reactor which was already a much-safer alternative than conventional nuclear reactors. In January 2020, GE Hitachi Nuclear Energy started the regulatory licensing process and it is about to become construction.
NuScale
The project began as a joint project between the Department of Energy and Oregon State University. The reactor is a light water reactor (LWR) with U fuel enrichment of less than 5% and a two-year refueling period. The project is known for an exceptional power output for a SMR (with each module having an electrical output of 60 MWe and scalability up to 12 modules). However, they are still waiting on approval for creating plant (which is believed to be operable in 2026).
OPEN100
OPEN100 is an SMR project developed by the Energy Impact Center, publishing the first open-source blueprints for a 100 MWe pressurized water reactor. Despite having significantly lower output compared to the NuScale project, this reactor is aimed to standardize the construction of nuclear power plants to cut down on cost and duration. This design could be built in as little as two years for $300mm. The template also allowed for site-specific alterations with 20% cost predictability. Emerging markets in Nigeria agreed to use the OPEN100 model to build the country’s first nuclear reactors in July 2021.
SSR-W
The Stable salt reactor is a nuclear reactor design proposed by Moltex Energy; it represents a breakthrough in molten salt reactor technology, to make nuclear power safer, cheaper, and cleaner. The use of static fuel salt in fuel assemblies avoids many of the challenges associated with pumping highly radioactive fluids whilst also complying with international standards. Materials challenges are also reduced significantly, given the lack of corrosion.
The Future of Reactor Design
ACP-100 is one of the world’s most original nuclear reactors; however, it struggled with using conventional nuclear power technology, as well as issues with cost and scalability. The BWRX-300 is the top safety choice within nuclear design; whereas, the NuScale design has a significantly higher power output than any other reactor option. The OPEN100 is the most economical and easily scalable model and the SSR-W is not only another top safety pick (by avoiding irradiated fluid usage), it also has newer technology with solid cost reductions (due to reductions in materials challenges) and equivalent power output.
INDUSTRY OVERVIEW & OUTLOOK
The nuclear power industry as a whole is rapidly growing. Overall, the market size of nuclear power is $41.1 billion with a projected valuation of $58.4 billion in 2030. With a CAGR value of 3.5%, there are key drivers of this steady growth in addition to inherent characteristics of nuclear power that prevents an explosive rise in value. The projected growth is largely being catalyzed by the growing demand for clean energy. This global demand is responsible for the development of innovation in the nuclear power industry.Within this drive for innovation, some key priorities are sustainability and cost, two things that the small modular reactors are designed to meet.
While the market size of small modular reactors, at $3.5 billion, is obviously significantly smaller than the industry as a whole, it is projected to experience much more rapid growth. In 2030, the small modular reactor market size is expected to be $18.8 billion, a CAGR of 15.8%. One of the main benefits of small modular reactors is their ability to cut costs of energy production. They are being transitioned to be used to power “small remote power grids.” Because the initial costs of manufacturing small modular reactors are lower, there is a major incentive for their implementation. In addition, when compared to large more traditional nuclear reactors, small nuclear reactors have the ability to be scaled. They are quicker to produce and more easily implemented into already existing power grids. This is another explanation for their more explosive growth when compared to the industry as a whole.
However, the novelty of the technology is a major inhibitor of the market’s growth. Currently there are no small modular nuclear reactors that are ready for use. The three key players in the small nuclear reactor development industry are NuScale, GE-Hitachi, and Terrestrial energy. These three companies have their own independent model designs that are undergoing advanced regulatory stages. Once the viability of these are verified, there is an expected meteoric rise in the industry. This will not be a simple process. The United States Nuclear Regulatory Commission outlines a few open policy issues regarding small modular nuclear reactors that need to be resolved in the regulatory process. They broadly include the following:
Appropriate Source Term, Dose Calculations, and Siting for SMRs
Offsite Emergency Planning (EP) Requirements for SMRs and other new technology
Insurance and Liability for SMRs
Security and Safeguards Requirements for SMRs
Within each of these key policy areas, there are individual levels that must be addressed. In other words, the efficacy of a model is not the only barrier to implementation and market growth.
Once there is approval on implementation of small modular reactors, there is not expected to be uniform growth across all regions. China and Japan are projected to drive the dominance of small modular reactors in the Asian Pacific region. China is working on key projects that are responsible for this. China plans on focusing on the development of generation III coastal nuclear power plants. Generation III reactors are the new wave of nuclear reactors that are designed to replace generation II ones. China’s aggressive push for this transition is expected to largely incorporate small modular nuclear reactors, priming them to be dominant in the industry. In addition to this, China is increasingly focusing on the direct development of offshore floating nuclear reactors, a main operationalization of small modular reactors, also driving growth. While Japan isn’t as aggressive with their approach, policymakers have placed increasing importance on decarbonizing the energy sector, incentivizing the growth of small modular nuclear reactors in the region.
ECONOMIC ANALYSIS
An important comparison between small modular reactors and larger traditional reactors is the application of the principle of economies of scale. Economies of scale address the cost efficiencies in the nuclear power industry. The economy of scale says that when the size of a nuclear power plant increases, the capital cost would decrease. This concept assumes that because of the initial investment and costs to initially start a nuclear power plant is best utilized when the plant is bigger and consequently produces more energy. Because of this, up until now, there had been an emphasis on building reactors sized up to 1500 MWe and sometimes larger. However, the___points out that that the economy of scale is only applicable when you are comparing two nuclear reactors of the same size. For example, the initial investment of raw materials is very different for small modular nuclear reactors than that of larger scale reactors. Which means that the evaluation of efficiency cannot directly be compared. The bigger doesn’t necessarily mean a more efficient use of investments.
More specifically, there are inherent features of small modular nuclear reactors that lower these initial investment costs. When they are made, they are designed to be produced in factories and easily transportable. The following are the most important benefits to the size of small modular nuclear reactors that justifies the violation of the economies of scale.
Modularization
Multiple units at a single site
New design strategy and solutions
Broadly, theincread potential for modularization of small modular nuclear reactors means that the components can be manufactured off site. This in addition to the advantages in transportation and assembly of the reactors allowed for initial investments to be lower. For the multiple units, this will allow for periodic build up of sites. Once one is established, it is easier to add more at a lower cost leading to an overall minimization of capital. Lastly, the new design solutions are relevant to the holistic simplification of the nuclear design process that increases the accessibility and scalability of nuclear power.
THE SCIENCE
All nuclear reactors have core elements that define their functionality and they include the following:
Fuel
Moderator
Control Rods
Coolant
Pressure Vessel
Steam Generator
Containment
Small modular nuclear reactors are a type of fission reactor. During nuclear fission, there is a specific fuel that is put into metal rods and arranged into groups called fuel rods. The fuel rods are put into water to control the fission reaction. Fission reactions, on a really simple level, split atoms up and utilize the energy released to power the reaction. When the fission reactor takes place, steam is produced from the water acting as a coolant, which serves to turn a turbine to create the electricity. In the case of small modular nuclear reactors, the fuel that undergoes the nuclear fission reaction is a low enriched uranium.
An important distinction between the small modular nuclear reactor and a traditional nuclear reactor is the design of its core, the primary location of the fission reaction. Because small modular nuclear reactors are small, there are specific constraints that need to be met in order for it to be successfully deployed. A comprehensive analysis of the core design lists the following as important design constraints:
MDNB and heat flux
Fuel and cladding temperature
Maximum Pressure Drop
Mass Flux
Another major distinction is in the integral configuration of the small modular reactor in comparison to a traditional nuclear reactor. In a small nuclear reactor, all of the primary components are internally placed within the reactor vessel. In contrast, a traditional nuclear reactor is a loop configuration where many of the components are placed external to the reactor vessel. This internal configuration of small modular nuclear reactors increases the size of the reactor vessel but overall minimizes the size of the nuclear power plant. This has important implications like lowering the input costs and increasing the ease of transportability.
In a commercial context, the small modular reactors each function as a singular reactor with an output of about 300 mW. However, because of their modular nature they can be assembled with multiple individual small modular nuclear reactors to have the same effect as a larger reactor. The individual parts of the reactors are pre manufactured in a factory and require little onsite investment in assembly. Thus, if the design constraints are effectively managed and the commercial small modular reactor passes regulatory issues, it will revolutionize the accessibility and cost effectiveness of nuclear power.
SUSTAINABILITY ANALYSIS
Small modular nuclear reactors are considered optimal solutions to the renewable energy crisis as it provides relatively higher power outputs whilst also fixing larger cost and waste management issues. The nuclear industry and the US Dept. of Energy envision micro-reactors to exist all over the world (including emerging markets) with minimal waste.
However, there are a few key issues. Nuclear reactors are large because of economies of scale (a reactor that produces three times as much power as an SMR does not need three times as much steel or three times as many workers). In fact, it was this reason that mainly contributed to the mass shutdown of many small reactors built in the U.S. in the mid-1950s and 1960s.
Although proponents would argue that the modularity of these reactors, as well as factory manufacturing would compensate for a lack of economies of scale, the road to creating specialized SMR fabrication centers would be long and difficult, with thousands of SMRs being produced at a price per kilowatt similar to larger reactors.
Moreover, modular construction hasn’t been recognized as a viable solution. SMR light water designs, like the NuScale design, require premature replacement of steam generation and the Westinghouse AP1000 reactors built in the U.S. and China have had significant construction cost overruns and schedule delays.
Currently SMRs struggle with cyclical issues:
There is no mass manufacturing supply chain (without mass orders)
There will be no mass orders without a supply chain
The SMR track record is also very low as there hasn’t been much promise outside of existing technology and power outputs that make the technology seem suboptimal to building larger reactors. Even licensing existing technologies has been incredibly expensive, with the NuScale SMR’s familiar light water design, requiring $1.5BN for development and certification.
There is also no realistic prospect that SMRs can make a significant dent in the energy transition process. For SMRs to consistently achieve the same cost of power production as the present large reactors, they would require a significant jump start and streamlined production processes (currently certification takes decades). However, even if these outputs are reached, the costs are supposed to be incredibly high.
Lazard, a Wall Street firm, estimates that the cost of utility-scale solar and wind power to be ~$40/MwH. On the flip-side, SMRs will require $160/MwH. Nuclear reactors are also not very suitable for responding to variability due to high fixed costs, so they don’t have any increased consistency that could be attributable to higher costs.
Consequently, there is no real sustainability or economic benefit from choosing to pursue SMRs compared to other renewable energy sources.