Small Modular Nuclear Reactors (SMRs)

Brandon A Moses
8 min readFeb 8, 2022


The Introduction:

A single neutron slams into the nucleus of a radioactive uranium-235 atom. The atom absorbs the blow, but becomes extremely unstable in the process.


The atom becomes so excited that it abruptly splits apart, forming two separate atoms and an additional three neutrons. These three neutrons become eager to form another bond thus latching onto the nuclei of another uranium-235 atom.

The process continues, generating more and more heat energy as the atoms burst apart. This chain reaction is called Nuclear Fission, and is the basis on how we create nuclear power today.

The Element U:

To be clear, nuclear power is NOT considered a renewable resource. This is because it requires an earth-metal called uranium (U) or plutonium (which I will talk about in a future blog). In its natural form, uranium is ~99.3% composed of an isotope called uranium-238. However, the main isotope that is used in nuclear reactions is uranium-235.

Isotopes are generally measured by the number of neutrons they hold, for example uranium-238 has 92 protons and 146 neutrons. Uranium-235 also has 92 protons but has 143 neutrons. When you add these up, 92+146 = 238, and 92+143=235.

Even though uranium is primarily made up of the 238 isotope, it cannot withstand nuclear fission (splitting of an atom’s nucleus into smaller nuclei to generate energy), therefore cannot be used as an energy source to generate electricity until it is separated. This isotope separation process is called “enrichment” and can be achieved through advanced technology such as gaseous diffusion, electromagnetic separation, centrifuges, and laser enrichment.

The Commodity:

Uranium can be found all over the world, with most mining operations located in Kazakhstan (~40%), Australia (~13%), Canada (~11%), Niger (~7%), and Nigeria (~7%).

In recent years, Uranium production has been somewhat sluggish. The COVID-19 pandemic has negatively affected mining operations at several major production sites in Canada and Kazakhstan.

According to several economic sources, uranium production is expected to recover around 6% over the next five years. However, the long-term future of uranium mining looks rather bleak, with a very slight increase into 2040.

You may ask, why would uranium mining not rapidly increase when nuclear power output is expected to rise significantly?

Well, for obvious reasons other than safety concerns and a changing economy, nuclear fission does not require a lot of uranium-235 to supply large amounts of energy. For example, a uranium-235 pellet produces the same amount of energy as one ton of coal.

As nuclear technology and reactor performance improves, physicists can string together a process so efficient that nuclear fission requires less and less uranium input.

One innovative approach to improving nuclear reactor performance is High Assay Low-Enriched Uranium (HALEU), which will be used to power next generation Advanced Small Modular Nuclear Reactors (SMRs).

The Foundations:

Advanced Small Modular Reactors (SMRs) are essentially mini nuclear power generators. They produce less than or equivalent to 300 megawatts of electrcity (MWe). Putting that into perspective, a single 300-MWe SMR can power upwards of 250,000 single-family homes a year.

SMRs differ significantly from large-scale nuclear reactors in numerous ways.

One, the size of SMRs are notably smaller. SMRs can range from ¼ to ⅛ the size of normal reactors. For scale, large nuclear reactor cooling towers can reach 650 feet in the air. Given that SMRs are a lot smaller, they require less of a protection zone. This means that these small reactors can operate close to population centers which would reduce the loss of power from long-distance transmission.

Second, SMRs can be made in stacks or “modules” that are installed together to form the device. This allows manufacturers to develop and assemble these reactors in a controlled factory rather than having to build a massive device on-site. The construction process takes significantly less time compared to traditional reactors. This can ultimately save manufacturers millions of dollars while improving the quality of construction.

Third, SMRs possess exquisite safety features, such as the ability to shut down autonomously and advanced shielding to mitigate the potential impacts of an accident.

Fourth, SMRs can be ramped up or scaled down based on energy demand, all you have to do is add on or take off a module. I wouldn’t be surprised if we see SMRs powering energy intensive places like remote military bases, hospitals, and even desalination plants in the future.

Finally and probably the most important in our world today, it costs much less to build a SMR compared to a large-scale reactor. A 1-gigawatt large nuclear reactor has a projected average cost well over $6 billion. Current estimates for SMRs are around ~$1.5 billion to manufacture.

The History and Outlook of NuScale:

One specific company that is currently in the process of manufacturing a SMR is NuScale. This company is currently privately held, but on the verge of an Initial Public Offering with the SPAC Spring Valley Corporation. Originally funded by the Department of Energy, NuScale’s SMR technology was further developed at Oregon State University. Throughout the years, the company has partnered with many wealthy investors and private research firms to perfect their manufacturing process and design. In 2020, NuScale became the first company to receive U.S. Nuclear Regulatory standard design approval for a Small Modular Reactor. The company’s goal is to redefine the nuclear energy industry and improve the quality of life for all humankind. Barring any delays, NuScale projects that their SMR will be commercially operational sometime in late-2026.

Some general features of NuScale’s system: It will be installed in a water-filled pool below ground, it will have 4–6 modules that self-cool, the system will be 65 feet tall, will weigh ~700 tons, have a >95% capacity factor, generate 77 megawatts of electricity (MWe), require 1/20 of the nuclear fuel compared to a large-scale reactor, be refueled every two years, operational lifetime of 60 years, and more. If you are interested in the actual technology of NuScale’s system, I would suggest reviewing their website.

The Counterarguments:

#1 Cost: It is way too expensive to manufacture a SMR. Even though it is a clean source of energy, investment in solar and wind will be way more cost effective in the long run.

The federal government is funding most of these projects, in fact, they gave NuScale over 500 million dollars in subsidies to manufacture a single SMR. Those essentially can be categorized as taxpayer dollars being gambled with. The upfront capital investment costs are also ridiculously expensive.

Additionally, SMRs are so far away from commercialization that only ¼ of the electricity produced by NuScale’s reactor has been subscribed so far (taken on by customers). Who knows if utility providers will want to take a risk on Small Modular Reactors with the rapid decline in price for solar and wind power. The Levelized Cost of Electricity (LCOE) of SMRs can only be estimated at this point and those estimates are not on the cheap side.

#2 Public Acceptance: Look at the statistics on American public support of nuclear energy. Half of our citizens do not want anything nuclear-related. Also, millions of people think it is unsafe. I mean think about it, would you want to live walking distance from a nuclear reactor?

Accidents sure do happen. Three Mile Island, Fukushima, Chernobyl, to name a few. Enhanced safety features are nice in theory, however everyone has seen the damage nuclear reactors (and weapons) can do. Imagine how much a nuclear disaster would cost this country, both economically and public health-wise.

#3: Waste — All spent nuclear fuel around the world is in temporary storage. Meaning, nuclear generation companies haven’t figured out what to do with the radioactive waste. And guess what? Nuclear waste or “spent fuel” stays radioactive for thousands and thousands of years. One proposed solution was the Yucca Mountain Repository in Nevada, however the mountain is far too small to deal with and could potentially contaminate groundwater supply in the area.

Before you even use the fuel, the uranium has to be mined. Research shows that uranium mining is linked to polluted acid drainage, toxins found in groundwater, increased radiation and radon levels, and other detrimental safety hazards.

#4: National Security — Nuclear generation and waste sights can be a potential target for terrorists organizations to either bomb the location or attempt to steal the equipment. As nuclear waste piles up, it becomes an even bigger national security risk to us all with a plethora of alarming consequences that could potentially unfold.

#5: Regulations: Any nuclear reactor that is planned to be developed faces a ton of challenges in the legal realm. A company will have to develop highly detailed safety, environmental, land, economic, and liability plans in order to just be approved for design. These loops and regulations have created such high barriers of entry into the industry that adequate competition may never exist.

The Conclusion:

Small Modular Nuclear Reactors definitely have an uphill battle ahead of them. The arguments above are valid and will probably hinder SMR deployment.

Although the arguments are a real concern, I do believe that SMRs have the potential to revolutionize our electrical grid.

The nuclear waste problem will eventually be figured out by reprocessing or the recycling of spent fuel. Public acceptance has widened in the past few years and will continue to do so as fossil fuels destruction becomes more evident. The government (DOE, Nuclear Regulatory) will likely work with SMR companies to help these systems come online and work through the regulations that they currently face. Finally, terrorists can attack at any moment, but fear shouldn’t be the reason to delay infrastructure that can significantly benefit our country.

Just like most things, I believe cost is the biggest obstacle facing SMR development.

The benefits of generating clean power on-demand will become vital moving forward. Yes, solar and wind energy are going to be critical to our economy, however our energy grid will require diversification. The intermittency of renewables plagues a problem, especially in a society where energy demands are sharply increasing. Obviously financing SMR technology with federal funding is risky, but this risk can have gigantic rewards. As laws and regulations change, a well diversified energy portfolio will set our economy up for success, bolstering our economic well-being through job creation and the beginning to a more sustainable America.

Whether you are a fan of Small Modular Nuclear Reactors or not, investments will continue to pour into the industry. Biden’s Infrastructure Investment and Jobs Act approved in late-2021 has a whole section written about SMR technology and where the funding will go. You can read further about it in Subtitle C — Nuclear Energy Infrastructure.

Another nuclear power technology that I will discuss in a future article will be microreactors (vSMR). These brand new designs are even smaller nuclear reactors and can be physically transported while in-use. If you are interested in hearing about vSMRs or other up-and-coming clean energy technology, be sure to give the blog a follow, I plan to post every 1–2 weeks.

*The opinions expressed are my own and not affiliated with my employer. This blog does not contain financial advice.