by: Olivia Columbus at Last Energy
Original article here

Despite their size – or, rather, because of their size – small modular reactors (SMRs) have a big role to play in the transition to clean energy.  

To fully understand the significance of this technology, we need to distinguish SMRs from the reactors that came before, as well as newer designs that both expand and complicate the future of nuclear energy.

SMRs: The First Ingredient in a Sustainable Energy Mix

SMRs serve a specific and powerful purpose in the energy industry.  

“Small” and “micro” describe a nuclear power plant’s size in terms of its power capacity (Provincial Energy Strategy, p. 55). SMRs are smaller than traditional nuclear reactors, which means they’re easier to construct and, in theory, should be less expensive – but in the global energy system, they’re no less powerful.

Like other nuclear reactors, SMRs harness nuclear to generate heat that produces energy. Generally, SMRs have a power output of up to 300 MWe per plant: about one-third of the generating capacity of larger, conventional builds, which can produce around 1,000 MWe.  

Given that 500 MWe can power a small city, energy suppliers can use multiple SMRs to meet the needs of an energy customer, be it a community, industrial site, or country. The Last Energy reactor alone – a 20-megawatt SMR – can power 20,000 homes, and with far less carbon, construction, and land requirements than traditional reactors.

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Nuclear Reactor Sizes Based on Output

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A Moment of Modularity

Unlike the reactors before them, some SMRs, like Last Energy’s PWR-20, are truly modular, meaning that all of their systems and components are factory-assembled and easily transported as units to other locations for installation. With an SMR, you’re not building a reactor from the ground up: you’re simply assembling the existing pieces.

Compared to preconstructed reactors and partially modular SMRs, the PWR-20 can be assembled quickly on-site. The speed to delivery is less than 24 months, while traditional, non-modular reactors can take over five years to build – and sometimes, decades. Case in point: in the U.S., construction on the Vogtle nuclear plant began in 2012 with projected startup dates of 2016 and 2017. Yet in 2023, it’s still under construction and at least $16 billion over budget.  

...And a Better Baseload

SMRs reduce costs and construction timelines, and they also provide a carbon-free, always-on baseload energy: the minimum amount of electric power delivered or required over a given period of time at a steady rate. And compared to renewable energy sources, SMRs are consistent and dependable: they supply power around the clock, regardless of weather conditions.  

Naturally, energy derived from wind, sun, and water is dependent on the weather. While these renewable energy sources are intermittent and variable, they can pair with nuclear for a distributed energy mix which increases grid reliability.

When a renewable energy goes down, some SMRs can even perform “load following,” meaning they increase or decrease their power output to balance changes in the electricity demand. Currently, nuclear plants are usually operated in baseload mode and less frequently in load following mode, but SMRs present an opportunity to introduce more flexibility and stability – and far less carbon – to our electric grids.  

Smaller Than Small: Microreactors

Microreactors are smaller than SMRs, and they typically produce less than 50 MWe: enough to supply power for some smaller communities in remote locations. In the 1950s, microreactors were first developed for military submarines, which relied on nuclear propulsion.  

Beyond their aquatic applications, microreactors present a crucial opportunity to deploy energy quickly and affordably to remote communities, and to increase grid resiliency and safety in those locations. Microreactors can be created and distributed even more quickly than SMRs: within weeks, designers can deploy them to military bases, communities affected by natural disasters, and other remote locations or urgent situations.  

While microreactors are still regarded as a form of emerging technology, their design is evolving to meet the growing demand for stable, low-carbon energy. Globally, cyberattacks and natural disasters threaten the stability of electric grids; but microreactors are compact, fully-assembled, and ready for transportation to energy-deficient areas, especially in the event of a blackout or another urgent disruption.

The Landscape of Nuclear  

Proven and Operational

Advanced reactors are subject to a mix of science, economics, and politics, but two categories of light water reactors (LWRs) are widely tested and commercially proven: pressurized water reactors (PWRs) and boiling water reactors (BWRs).

In simplest terms, a PWR pressurizes water so that it heats, but doesn’t boil. The pressurized water carries heat to the steam generator, and the production of steam generates electricity by turning the turbine generator inside the PWR.

Compared to PWRs, BWRs take the extra step and boil the water. That water is converted to steam, then recycled back into water by the “condenser” component, to be used again in the heating process. BWRs are simpler than PWRs, with only a single circuit that pressurizes water until it boils. These reactors are common in the U.S., Japan, Sweden, and Taiwan, and makes up approximately 15% of the global supply of active reactors.

On the Horizon: Gen IV Nuclear  

In addition to SMRs, some nuclear scientists are developing alternative nuclear technology, often called Gen IV reactors. These reactors require more research, and most are only partially modular; still, this technological generation features some promising projects, including traveling wave reactors (TWRs).  

TWRs, like those designed by TerraPower, are uniquely designed to operate after startup using only natural or depleted uranium, which allows for higher fuel utilization and less uranium mining. In the long-term, this technology could enable even more cost savings and clean electricity production on a larger scale; but in the U.S. alone, the actual implementation of Gen IV reactors is still two to four decades away.

Unproven Nuclear Reactor Designs

Beyond PWRs and BWRs lies an unsteady ground of untested and unproven reactor designs.  

While many companies recognize the potential of nuclear, so-called “advanced” reactors don’t have an operating supply chain to model, and they’re largely based on unproven concepts introduced more than 50 years ago. Many of these designs use sodium or molten salt or gas for cooling, backed by claims of greater safety, affordability, and security compared to the LWRs in predominant use today.  

Rather than contend with the regulatory challenges of commercializing unproven, untested reactors, a 2021 report by the U.S. Union of Concerned Scientists recommended investing more research into the improvement and expansion of LWRs: ideally, ones that are actually small and actually modular.

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Last Energy: A Case Study in Small Modularity

In keeping with this recommendation, Last Energy designed the PWR-20: a 20-megawatt SMR. It’s a modular, factory-built nuclear plant, and it employs the existing technology of PWRs, which are the most common type of nuclear reactor. On-site, all modules of the PWR-20 are quickly connected and commissioned, which eliminates on-site construction.  

Using only proven and operational technology, Last Energy relies on existing supply chains to deploy the PWR-20 design with speed and accuracy.  

Crucially, the Last Energy approach to nuclear energy is scalable to larger energy demands, simply by increasing the number of units. And with a power output of 20 MWe, the PWR-20 offers behind-the-meter solutions for industrial facilities as well as distributed baseload for grid applications.  

The size and modular building approach means Last Energy’s PWR-20 is under $100 million per unit, making it sized for private capital markets, and it can be delivered in approximately 24 months, quickly bringing 24/7 clean energy to industrial customers.  

SMRs: Small Potatoes or the Future of Nuclear?

Interest in SMRs is rising as countries recognize the need for a more flexible, powerful energy source with readily available parts and less complicated construction (Provincial Energy Strategy, p. 147). In some regions, such as the Province of Limburg in the Netherlands, scientists advocate for a sustainable energy mix of SMRs and “mini-SMRs,” or microreactors, with a unit power of 20-50 MWe each (p. 8).  

In consideration of the geotechnical conditions of Limburg, the report endorses a combination of SMRs and mini-SMRs based on proven LWR technology. In view of Limburg’s energetic needs and financial constraints, large plants are nearly impossible to fund during the 2030-2035 period, given the geotechnical conditions needed to cool water in large LWRs (p. 8).  

Although this report highlights the possibilities of nuclear in just one region of the world, it has far-reaching implications for the deployment of nuclear energy in other areas. Above all, it highlights the importance of size when assessing nuclear reactors, and how the appropriate combination of plants can sustain a rich, commercially competitive, and reliable mix of carbon-free energy.

Recapping the Rewards of SMRs

In the world of nuclear, smallness reigns supreme for several reasons:

1. Due to their compact, modular design, the construction of SMRs is fast and efficient. Their components can be factory-built, like Last Energy’s PWR-20, which ultimately reduces cost overruns. This is a common concern when building reactors with larger builds, which often extend beyond the projected construction timeline.

2. Using existing supply chains, SMRs can be easily distributed. If they’re factory-assembled, they can also be transported as units to various locations for installation.  

3. Despite their small size, SMRs produce large amounts of low-carbon electricity. Consequently, many countries envision SMRs and microreactors as essential components of a carbon-free future.

4. SMRs also have reduced fuel requirements: every 3 to 7 years, versus every 1 to 2 years for large, conventional plants. Some SMRs are designed to operate for 30 years without refueling.  

5. With progressive designs like the PWR-20, SMRs and other commercially proven reactors have the potential to replace our dependence on renewables. In theory, PWR-20 plants can be built close to industrial facilities and supply round-the-clock-carbon-free power, or plugged into the grid when utilities need more clean baseload power.  

Fittingly, SMRs supply a succinct answer to the energy trilemma. They’re small, powerful, and their goals are targeted: reduce costs, support sustainability, and increase the security of our global energy reserves.  

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NuScale VOYGR^TM SMR power plant

The U.S. Nuclear Regulatory Commission (NRC) issued its final rule in the Federal Register to certify NuScale Power’s small modular reactor.

The company’s power module becomes the first SMR design certified by the NRC and just the seventh reactor design cleared for use in the United States.

The rule takes effects February 21, 2023 and equips the nation with a new clean power source to help drive down emissions across the country.

Historic Rule Making

The published final rule making allows utilities to reference NuScale’s SMR design when applying for a combined license to build and operate a reactor.

The design is an advanced light-water SMR with each power module capable of generating 50 megawatts of emissions-free electricity.

NuScale’s VOYGR™ SMR power plant can house up to 12 factory-built power modules that are about a third of the size of a large-scale reactor. Each power module leverages natural processes, such as convection and gravity, to passively cool the reactor without additional water, power, or even operator action.

The NRC accepted NuScale’s SMR design certification application back in March 2018 and issued its final technical review in August 2020. The NRC Commission later voted to certify the design on July 29, 2022—making it the first SMR approved by the NRC for use in the United States.

"We are thrilled to announce the historic rulemaking from the Nuclear Regulatory Commission for NuScale’s small modular reactor design, and we thank the Department of Energy (DOE) for their support throughout this process,” said NuScale Power President and Chief Executive Officer John Hopkins. “The DOE has been an invaluable partner with a shared common goal – to establish an innovative and reliable carbon-free source of energy here in the U.S. We look forward to continuing our partnership and working with the DOE to bring the UAMPS Carbon Free Power Project to completion."

“SMRs are no longer an abstract concept,” said Assistant Secretary for Nuclear Energy Dr. Kathryn Huff. “They are real and they are ready for deployment thanks to the hard work of NuScale, the university community, our national labs, industry partners, and the NRC. This is innovation at its finest and we are just getting started here in the U.S.!”

NuScale is currently seeking an uprate to enable each module to generate up to 77 megawatts. The NRC is expected to review their application this year.

Supporting SMR Development

The U.S. Department Energy provided more than $600 million since 2014 to support the design, licensing, and siting of NuScale’s VOYGR SMR power plant and other domestic SMR concepts.

DOE is currently working with Utah Associated Municipal Power Systems (UAMPS) through the Carbon Free Power Project to demonstrate a six-module NuScale VOYGR plant at Idaho National Laboratory.

The first module is expected to be operational by 2029 with full plant operation the following year.
 
UAMPS finished subsurface field investigation activities at the proposed INL site and expects to submit a combined license application to the NRC in the first quarter of 2024. 

NuScale Power has 19 signed and active domestic and international agreements to deploy SMR plants in 12 different countries, including Poland, Romania, the Czech Republic, and Jordan in addition to the Carbon Free Power Project.

Learn more about NuScale Power design certification process with the NRC. 

The last nuclear-powered guided missile cruiser USS South Carolina (CGN-37) left U.S service in 1999
CORBIS VIA GETTY IMAGES

Craig Hooper Forbes Senior Contributor
I evaluate national security threats and propose solutions.
Original article here

Over the next decade, a combination of strategic, economic, and environmental concerns will bring modern, fourth-generation nuclear reactors to the waterfront. American ports and ship operators that begin preparing the U.S. waterfront for nuclear power today—building a trained nuclear-ready workforce and establishing operational protocols for nuclear vessels and support infrastructure—will enjoy enormous competitive advantages.

Today, new modular nuclear reactor designs are evolving beyond the grand-scale, thousand-megawatt “modular” pressurized or boiling water reactors used in America’s current-day nuclear power plants, offering smaller, scalable options for size and safety. The difference is stark—in Georgia, the Vogtle Electric Generating Plant is preparing to commission two big new reactors and become a massive four-reactor, 5000-megawatt regional generating center, while modular reactor startup NuScale Power offers a comparatively pint-sized four-reactor module set capable of generating up to 308 megawatts.

The idea that small, scalable “Generation IV" nuclear reactors can offer lower-risk reactor designs in facilities with a far smaller-footprint has fueled widespread investments in new modular reactor technology.

It is only a matter of time before these new reactor designs evolve to where they are “marine-ready” and able to meet U.S. waterfront’s future power generation needs both ashore and afloat.

New Nuclear Tech Faces An Uphill Battle

But getting the Navy to embrace wider use of nuclear power is going to be difficult. Still organized along Cold War lines and riven by long-standing intra-service rivalries, the Navy—as long as it lacks a dynamic Rickover-like leader capable of forcing big changes—is unsuited to adopt a new propulsion technology anytime soon.

The Navy treats nuclear power as a world into itself, as a separate “Naval Reactors” community. The Navy’s four-star Director of the Naval Nuclear Propulsion Program serves as the Navy’s gatekeeper for nuclear technology, and, as the leader of a conservative, risk-averse bureaucracy, that leader is not likely to support wider Navy adoption of hot and new nuclear technologies.

With a lot on its plate, Naval Reactors may simply be too busy to really focus on something new. Already stressed by America’s big submarine recapitalization program—and further pressurized by AUKUS, an effort by Australia, the United Kingdom, and the United States to bring nuclear-powered submarines into the Australian Navy—new technologies may crush the Service.

But the bifurcated bureaucracy is entrenched. One nuclear-certified Navy Captain wrote, in a 2019 U.S. Naval Institute Proceedings article, that “nuclear-trained officers serve two masters—their parent warfare community and Naval Reactors” and must step away from the conventional surface warfare promotion pathway to work in nuclear-related jobs aboard aircraft carriers. The subsequent lack of proficiency in conventional naval surface combatants, he worried, would put nuclear certified surface warfare officers at a disadvantage at sea, while efforts to gain proficiency at sea would move nuclear-certified officers too far away from nuclear propulsion systems.

In addition to the challenges facing Navy in training and personnel management, the U.S. Navy’s institutional biases against merchant ships may blind the service to interesting opportunities in using nuclear power in the Navy’s big fleet of auxiliaries. In the Cold War, aspiring surface Navy leaders were often required to skipper otherwise unglamorous tankers and auxiliary ships—former Chief of Naval Operations, Admiral Mike Mullen, often recalled that he once commanded the USS Noxubee (AOG-56), an ignominious gasoline tanker. As the Cold War wound down, these duties were turned over to civilian operators, and their naval stewards at the Military Sealift Command were downgraded in importance. But, today, nuclear-powered auxiliary ships and freight-carriers might be a great investment for America, helping the country better understand the technical challenges ahead as the world races to “marinize” nuclear power.

Needless to say, the atmosphere in the Navy’s nuclear bureaucracy is not set up to promote creative new ideas—it wants to safely execute an established mission set. To that end, the U.S. Department of Defense may need to push the stressed Naval Nuclear Propulsion Program to evolve. If the future of warfare is pointing towards the need for new, energy-hungry technology—and away from traditional liquid hydrocarbon fuels—the Department of Defense will be obligated to step in and change things.

And that may already be happening. In press releases promoting “Project Pele,” an innovative Department of Defense effort to explore modern micro-reactors, the U.S. Navy is conspicuously absent in what is billed as a “whole-of-government effort” to “advance energy resilience and reduce carbon emissions while also helping shape safety and nonproliferation standards.” Instead, the Army Corps of Engineers gets a bigger billing, alongside the Department of Energy, the Nuclear Regulatory Commission, the National Nuclear Security Administration, and NASA.

How The Pentagon Can Help Navy Can Muddle Through

Even if the Naval Nuclear Propulsion Program won’t “play ball” and “Big” Navy rejects the potential for nuclear-powered combatants or auxiliary ships, there are other things the Department of Defense can do to help a reluctant Navy “set the table” for a wider exploitation of nuclear power in the maritime.

First, the Department of Defense can continue to “help” the Navy both test basic strategic assumptions and “incentivize” the adoption of technologies that have wider potential to address national needs. A stream of basic studies on the feasibility of nuclear icebreakers, nuclear-powered next-generation surface combatants like the DDG(X), nuclear-powered auxiliaries, and nuclear-powered subsystems might be useful.

Second, the Pentagon can press the Navy to develop new nuclear-ready shipyards in areas that could use the investment—Baltimore, Puerto Rico and Guam all offer interesting opportunities. With the Navy slowly awakening to the heretical idea that pricey, taxpayer-owned shipyards can and do save taxpayer money, the service is openly mulling the idea of starting one or two new public shipyards. If established, these new yards will help the Navy overcome a backlog in nuclear submarine and aircraft carrier maintenance. But, in a decade or two, they will have a trained workforce ready to support a wave of new nuclear-powered surface ships.

Third, the Defense Secretary can help get the Navy to discuss notional concepts-of-operations for nuclear vessels. In conjunction with the U.S. Department of Homeland Security, the U.S. Coast Guard and others, the service can lead another all-of-government initiative to dust off old operating guidelines from back when NS Savannah, America’s first—and only—nuclear-powered merchant ship, sailed the seas, and start re-developing the regulatory framework needed to support the safe operation of nuclear-powered commercial and military vessels in U.S. waters.

And, finally, the Department of Defense can recognize and work to mitigate pressure on Naval Reactors that may constrain innovation. If the organization is struggling to contend with the daily grind of maintaining—and growing—America’s nuclear force, and seems threatened by the prospect of bringing nuclear submarines into Australian service, then the organization may need both guided reform and funding to better position the service for new nuclear technologies.

The challenge is pretty stark. Either push forward on nuclear technology and lead in the maritime—or simply wait around until China starts developing nuclear-powered merchants and surface combatants, making new nuclear technologies impossible to ignore.