Nuclear Notes is produced by the Breakthrough Institute, and covers the policy, regulation, technology, and business of advanced nuclear energy in the United States and beyond.
Every Thursday, we track what’s really going on in the field: the new rules moving through the Nuclear Regulatory Commission, the advanced reactors moving from design to deployment, the companies going public and the utilities merging, and the executive orders and acts of Congress reshaping how the country builds. We explain not just what happened, but why it matters and how the pieces fit together.
Advanced Nuclear May Also Need Advanced Cooling
A hot summer and erratic rainfall are reminders that most power plants need copious amounts of cooling water. Most nuclear designs, including all the ones now operating, boil water to spin turbines and make electricity. That does not consume water, because the steam is condensed back to water for re-heating. But condensing the steam requires either large amounts of water that is raised in temperature by several degrees and then returned to a river or ocean, or a smaller amount that is evaporated.
In some locations, large cooling-water requirements are not a problem. Nuclear plants have used these systems safely for decades, generally with very limited environmental impact. But cooling water can create challenges in particular locations or during periods of heat and drought.
France is generally not short of water, but the rivers that supply cooling water are so warm this summer that some plants have had to shut down or throttle back. Électricité de France, the national operator, has reduced nuclear output by 6.3 gigawatts, which is about 14 percent of total power demand.
The problem isn’t limited to rivers in France; in 2012, one of the two reactors at Millstone Point in Connecticut had to shut down because the Atlantic Ocean had gotten warmer than the designers ever anticipated, and the temperature of the cooling water exceeded the limit set in the plant’s license. This temperature limit on the cooling water exists because if the river or ocean water is too warm, it won’t absorb enough heat to condense the steam back into water in the primary loop. When the plants were designed, in the 1960s and 1970s, engineers did not bother to figure out precisely what the upper temperature limit should be because they did not anticipate the Atlantic Ocean getting so warm. But in recent years they have sharpened their pencils and figured out that the plants could safely operate at higher temperatures.
But refining the calculations has not been enough in some instances, where reactor operations have actually been curtailed.
How, then, to assure cooling for four giant reactors in the hot, dry panhandle of Texas? That is a problem for Fermi America, a start-up that leased land from Texas Tech outside Amarillo and announced plans to build 11 gigawatts of generation, including four Westinghouse AP1000 reactors. The rest is combined-cycle natural gas units, which burn gas in a machine resembling a jet engine, and use the waste heat to boil water into steam to make more electricity.
Fermi’s co-founder, Toby Neugebauer, said that his company “isn’t some out-of-town operation parachuting in. Our leadership is from West Texas — we grew up on this dirt, and we care about the land and its resources.” Plants like Millstone have no cooling towers and draw water directly from the oceans, returning it slightly warmed. But that idea won’t help in northern Texas.
There, the usual solution is a cooling tower. Plants with cooling towers pour water over pipes filled with hot water, and let evaporation on the outside of the pipes do the cooling of the water inside. But these still use substantial amounts of water, visible as steam above the towers.
The numbers vary with atmospheric conditions, but a cooling tower may evaporate as much as 800 gallons per megawatt-hour, or in a 1,000 megawatt reactor, 800,000 gallons an hour. That is a challenge in some locations.
Nuclear plants use more cooling water than coal plants of the same capacity, because some of the waste heat in a coal plant goes up the chimney. They also use more water than combined-cycle natural gas plants because the portion of those plants’ output that comes from the jet engine does not make steam. But the jet’s hot exhaust is used to make steam, which does have to be condensed.
But a solution for nuclear may be to use air instead of water for cooling.
In December, Fermi America announced a memorandum of understanding with a Hungarian company, MVM EGI Zrt., for a hybrid system that would use air to cool the steam back into water. MVM already sells such systems for fossil-fired plants.
Some anti-nuclear groups have seized on the water problem. The Institute for Energy Economics and Financial Analysis pointed out in a report last week that no nuclear plant now uses such a hybrid system, and claimed it was unproven and unlicensed.
But it is proven. Some fossil-fueled plants make substantial use of air cooling, some only seasonally, when river water is warm or scarce. The Energy Information Administration calculated in 2018 that about 3 percent of U.S. generation uses air cooling, although none of that is nuclear.
Southern Nuclear evaluated air cooling for its Vogtle plant before the plant was built. One problem is that the fans needed to move the air consume a significant amount of the plant’s power. (The precise amount depends on the ambient air temperature). Southern concluded that an air-cooled condenser was “not feasible from a reliability, cost, or environmental standpoint.”
NuScale Power found otherwise. It developed a detailed air-cooled design, which was intended for its lead plant at the Idaho National Laboratory. Using an air-cooled design produced a penalty of 5 to 7 percent of the plant’s electricity output, depending on ambient air temperature. If the region were dry enough, that cost would be acceptable. But that project was scrapped for other reasons.
The need for water may be a weak spot for all thermal-electric generators, but nuclear energy is well-positioned for a drought-prone world. Located in the Arizona desert, the Palo Verde Nuclear Generating Station is long known as the only large nuclear plant in the world not built near a major body of water. To cool its reactors, the plant relies on a 40-year agreement with metropolitan Phoenix to purchase treated wastewater annually. Nuclear is also a potent source of energy for making drinking water from the oceans.
A Mining Giant and A Potential Nuclear Giant Settle on Terms
Australia will begin exporting uranium to India, twelve years after a trade deal was initially struck. The delay came from Australia’s insistence that its uranium not find its way into India’s nuclear weapons program.
India never signed the Treaty on the Non-Proliferation of Nuclear Weapons of 1970, and exploded what it called a “peaceful nuclear device,” code-named Smiling Buddha, in 1974. In response, major nuclear exporters embargoed India for decades.
But India has a huge potential market for nuclear energy. The country is short of power—annual electricity consumption in India is about 1,400kilowatt-hours per person, compared to about 12,000 in the United States—and struggles with air quality from coal pollution. It has 24 reactors in service, with a total of about 8.8 gigawatts, about ten more under construction, and ten planned after that. Its goal is 100 gigawatts by 2047.
The country has a mix of reactors, including an adaptation of the Canadian CANDU design that runs on unenriched uranium. The Russian state nuclear monopoly is building a complex of six pressurized water reactors at the Kudankulam nuclear complex in Tamil Nadu. Two are already in operation. India currently imports its uranium from a number of countries including Russia, Kazakhstan, and Canada.
The Indian prime minister, Narendra Modi, and the Australian Prime Minister, Anthony Albanese, signed an agreement in Melbourne last week. Price and volume were not disclosed.
India has only low-grade uranium ore, although it does have an abundance of thorium, a radioactive material that is not fissile, but can be converted into the fissile isotope uranium-233 by absorbing a neutron in a reactor. It has been developing a thorium fuel cycle. One company, with help from the Department of Energy, has developed a fuel package that could permit that transformation inside a CANDU. But another route is to import uranium.
A Lot of Small Companies Have a Lot of Support on Wall Street
The publicly traded companies that are pure-play small modular reactor developers have a collective market value of $21.2 billion, according to a recent tally by Robert Bryce, who is a nuclear advocate but is skeptical of the prospects of some of the companies.
Two-thirds of the market value is in two companies, Oklo and X-energy. And Holtec International, newcleo, and NuCube Energy plan initial public offerings as well.
Holtec filed paperwork with the Securities and Exchange Commission last week for an Initial Public Offering, stressing its plans to build small modular reactors of its own design.
The two nuclear developers that may have the strongest short-term prospects aren’t on the pure play list. The first is GE Vernova. A GE Vernova’s BWRX-300 reactor is already under construction in Ontario, with strong indications of sales of more, but it isn’t a pure play; the company also makes gas turbines and other electrical equipment. The second is Westinghouse, which could see orders for a fleet of ten big AP1000 reactors, and isn’t publicly traded at all. It is privately held by Brookfield Asset Management (a Canadian turn-around firm), and Cameco (a Canadian uranium mining company).
Fusion Goes Public Too
This week, General Fusion, of Richmond, British Columbia, became the first pure-play fusion company on Wall Street. It went public on the Nasdaq. A second fusion company, TAE Technologies, based in California, is supposed to go public later this year, in a merger with Trump Media & Technology Group Corp.
General Fusion hopes to demonstrate a test apparatus soon that will generate more electricity than it requires to create fusion, and to be in commercial operation by 2035.
Politico calculates that the fusion industry as a whole has raised more than $14 billion since 2021, although a commercial-scale fusion reactor is still years away.
And a Munich-based company, Proxima Fusion, announced this week that it had raised €411 million, about $470 million, which would value the company at €2.4 billion, or $2.75 billion.
No Restart Yet, But TMI-1 Can Store New Fuel
The Nuclear Regulatory Commission has given permission to Constellation Energy to accept new fuel for the reactor now known as the Crane Clean Energy Center.
When the company closed the plant in September, 2019, it had a large inventory of partially-used fuel. But to save money in the decommissioning process, operators bundled up the fuel assemblies that were only one-third or two-thirds used with completely used fuel, to minimize the number of dry casks they would need. When Constellation decided in late 2024 to re-open the reactor, it ordered new fuel.
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