Nuclear power is the ugly duckling of zero-carbon energy. Despite representing the statistically safest and most efficient energy source, atomic energy has faced an uphill climb in efforts to expand its share of the energy mix.
In fact, the United States will generate about the same amount of electricity from nuclear power in 2022 as it did in 2012. That reflects industry-wide efficiency upgrades over the years (called "uprates") and the closing of several reactors. More are scheduled to close in the coming years.
Industry remains hopeful in a brighter future. Ambitious startups and joint ventures are developing next-generation nuclear reactors. Designed to be smaller and deploy enhanced safety features, companies hope the next wave of reactors address the major limitations of the existing fleet.
Next-Generation Nuclear Reactors, Explained
Perhaps the single biggest criticism of nuclear power today is the cost. The poster child for recent economic challenges is the Vogtle nuclear power plant in Georgia, which aimed to expand the existing site with Unit 3 and Unit 4. The two new reactors will represent the first new commitment to nuclear energy in the United States since the 1979 Three Mile Island catastrophe.
Unfortunately, Vogtle has become synonymous with cost overruns and delays. Whereas original estimates expected total costs near $14 billion, the latest estimates are more than twice that amount. The reasons are complex and nuanced, such as the simple fact no domestic engineering firms have experience building nuclear reactors. Another multi-year delay was caused by confusion over regulations relating to the movement of dirt at nuclear sites. Seriously.
The fact remains that building new nuclear power infrastructure is really, really expensive. That's why next-generation nuclear power plants are tackling economics head on.
Many next-generation reactor designs are small modular reactors (SMR). As the name implies, these units are very small -- they can be less than one-tenth the power capacity of traditional reactors. That creates several potential advantages.
- Modular reactors could be manufactured at a factory, shipped to the power plant, and installed once on site. That ensures better quality control of components and reduces construction time to as little as 2.5 years. Vogtle Unit 3 and Unit 4 have been under construction for 10 years.
- SMRs could be installed at existing thermal power plants to provide new life. A soon-to-be-retired coal-fired, nuclear, or natural gas-fired power plant could potentially be retrofitted with an SMR much more easily than creating a new power plant from scratch.
- Smaller reactors with unique designs can load follow, meaning they can power up or down very quickly -- sometimes in as little as 20 minutes. This would make them complementary with intermittent renewable energy sources, unlike always-on conventional nuclear.
Each advantage could result in faster startup and lower costs.
What Companies are Investing in Next-Gen Nuclear?
There are a handful of intriguing ideas for continuing America's strong history of atomic innovation. Many designs are further along than you may think – and receiving significant funding from the U.S. Department of Energy. Each of the following three reactors could be operational by 2030.
X-energy: The startup is developing the Xe-100 advanced reactor design. The power capacity of 76 megawatts is significantly smaller than the 1,215 megawatts wielded by each new reactor at Vogtle. Importantly, X-energy thinks the Xe-100 reactor would be virtually meltdown proof.
The novel SMR uses a pebble-bed design similar to a gumball machine. Each pebble is about the size of a billiard ball and contains tristructural isotropic (TRISO) uranium fuel, can be cycled through the reactor over a three-year period, and the spent fuel can be stored immediately without additional cooling.
The SMR can operate at high temperatures, potentially enabling the simultaneous production of clean hydrogen, and has a passive safety system embedded in the design. In other words, the Xe-100 doesn't require large amounts of local water sources, pumps, or other mechanisms to shutdown in an emergency – it lets thermodynamics shut off the reaction.
The downside of Xe-100 is that it requires an entirely new fuel source in TRISO pebbles, but X-energy has received DOE funding and successfully demonstrated fuel manufacturing capabilities, too. The specific fuel type, called high-assay low-enriched uranium (HALEU), could be used for other advanced reactor designs. The first fuel manufacturing facility could be operational by 2025, while the first power plant could be generating electricity by 2028.
TerraPower: The startup is developing the Natrium advanced reactor design. The 345-megawatt reactor is larger than the Xe-100, but still small by traditional reactor standards. To be clear, up to four Xe-100 reactors are expected to be combined, resulting in roughly the same sized power plant.
The Natrium reactor was designed with the help of GE Hitachi. It's a sodium-cooled fast reactor, which means it has passive safety systems ("sodium-cooled") and could consume unique fuels ("fast reactor"). A fast reactor could theoretically consume spent nuclear fuel as its power source.
Additionally, Natrium offers high operating temperatures and a novel energy storage system, which could increase output 45% to 500 megawatts for more than 330 minutes when the grid craves more juice.
TerraPower's advanced reactor design could complement regional power grids with very high renewable energy penetration. It could also be used to produce hydrogen at lower costs and higher volumes than green hydrogen projects relying on wind or solar farms.
The company expects the first power plant to be operational in the late 2020s at the site of a retiring coal-fired power plant in Wyoming.
NuScale: NuScale (SMR) went public through a SPAC in early 2022. The company is developing VOYGR power plants based on its modular reactor technology. Each unit has a power capacity of 77 megawatts, making it much smaller than existing reactor designs.
Unlike Xe-100 and Natrium, the VOYGR design utilizes traditional fuel sources, which could accelerate adoption. The novelty comes from the physical reactor design, which relies on water and good-old gravity to heat and cool steam. The simplified design avoids pumps to circulate water through the reactor, which results in a passive safety system.
NuSclae has signed a memorandum of understanding (MOU) with Xcel Energy (XEL) to consider future commercial deployments of the VOYGR power plant. That could include SMRs delivered to existing power plant sites or new sites entirely.
Xcel Energy is always at the forefront of energy. It was among the first electric utilities to invest heavily in onshore wind power, has ambitious plants for utility-scale solar, and is exploring the potential to generate hydrogen from its existing nuclear fleet. The MOU with NuScale is the latest commitment to funding innovative new ideas.
