Bill Gates' TerraPower to start building first US SMR Nuclear power plant in June

Bill Gates helped found TerraPower in 2006, and is its Chairman.

According to CEO Chris Levesque, its Natrium-branded reactors cost about half of today’s standard water-cooled reactors, partly because it uses molten sodium as a coolant, enabling lower operating pressures and hence fewer redundant safety systems using simpler materials.

‘The company has secured pledges from the US government to provide up to $2bn to complete work at TerraPower’s first plant in Kemmerer, Wyoming, and it will apply for a construction permit from US regulators this month for its reactor’, targeting completion by 2030.

'The Kemmerer reactor would serve as a demonstration project but would become a full-scale commercial plant upon completion. TerraPower and its utility partner PacifiCorp — a unit of Warren Buffett’s Berkshire Hathaway — said in October 2022 that they would study the feasibility of deploying another five Natrium reactors by 2035. ’

‘TerraPower and GE Hitachi Nuclear Energy brought together their decades of unparalleled design expertise and technical capabilities to develop the Natrium™ technology, which features a cost-competitive sodium fast reactor combined with a molten salt energy storage system. This unique combination will provide clean, flexible energy and stability, and integrate seamlessly into power grids with high penetrations of renewables.’


Wyoming is all-in for nuclear power. Multiple communities were vying for the TerraPower facility. Wyoming communities and businesses are courting companies that are interested in manufacturing portable micro reactors, and there are a number of companies that are working on projects to mine uranium and rare earth minerals within the state.


Hi MedicineBow - it’s great that Wyoming is eager to diversify away from its dependence on coal into cleaner energy sources, particularly as one of the top suppliers of energy resources in the US

Let’s hope TerraPower can successfully scale up its first SMR as a role model for further such projects


Cost competitive with other large nuclear reactors, but not competitive with renewables or natural gas fired combine cycle turbines. The Natrium plant is designed for 345 MWe at cost of $4 billion. Currently Westinghouse AP1000 reactor is designed for about 1100 MWe at cost of $15 billion. Which seems to me to be about the same MWe / $.


One hopes the learning curve will give future Natrium plants a cost advantage. The first of everything has to allow for the unanticipated.


Hi jaagu - thanks for your response

SMRs are intended to be cost competitive and safer alternatives to traditional large water cooled reactors by applying some of the hard lessons learned over decades with the latter

Traditional reactors carry all kinds of stigmas across continents, so getting one built nowadays at anything close to a competitive cost/risk balance - at least in democratic countries - is daunting, to say the least.

'SMRs are relatively small and flexible: they have a power capacity of up to 300 MW(e) and their output can fluctuate in line with demand. This makes them particularly attractive for remote regions with less developed grids, but also for use as a complement to renewables and for non-electric applications of nuclear power. SMRs can be manufactured and then shipped and installed on site, so they are expected to be more affordable to build.

Countries with established nuclear power programmes have been managing their spent fuel for decades. They have gained extensive experience and have proper infrastructure in place. For these countries, management of spent fuel arising from SMRs shouldn’t pose a challenge if they opt to deploy SMRs based on current technologies, said Christophe Xerri, Director of the Division of Nuclear Fuel Cycle and Waste Technology at the IAEA.’

As for gas turbines, sure, they’re cheaper to build/operate in dollar terms - but at what environmental cost?

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I just posted cost overruns on France’s third generation pressure water reactor on the Nuclear Energy board.

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A SMR rated at 300 MWe is not small. I have a hard time believing that a 300 MWe SMRs can be manufactured in one piece and installed on site. Therefore, I do not believe they will be more affordable to build.

Jaak (nuclear engineer and engineering manager who worked on the design, analysis, licensing and construction of several nuclear power plants (Pilgrim, Susquehanna, San Onofre, Diablo Canyon, Palo Verde, and others)

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For reference:
Modern nuclear subs have a thermal power output of 150 - 200 MWe
The latest A1b carrier reactor is 700 MWe thermal.
Thermal output is the steam produced so you then need to run it through a turbine, which is going to be about 30-40% efficient

So the electrical output is about
sub: 50-80 MW
carrier: 200-300 MW



Hi jaagu - thanks for sharing your nuclear expertise with us
As with every new approach to solving a problem, financial/commercial viability can’t really be evaluated until pilot projects like the Kemmerer SMR really get going.

It’s good to remain skeptical, as long as we recognize the many challenges in traditional heavy water large scale reactors that remained unresolved even after decades of global experience with them

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Their website says:

TerraPower anticipates submitting the demonstration plant’s construction permit application to the NRC in mid-2023. The plant is expected to be operational in the next seven years, aligning with the ARDP schedule mandated by Congress.


Do you know the status of construction permit?

TerraPower has filed its permit application and is beginning construction of some of the non-nuclear elements. Here is a link to an article from a Wyoming based online news source:
It is going to be a long process.


Thanks for the update :smiley:

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The online article writes:
“Nuclear power in America is making a comeback, and Wyoming is where it’s all happening.
From digging up vast deposits of uranium to becoming a vendor for nuclear reactor parts, Wyoming is at the center of all things U.S. nuclear.”

Navajo Indians are suffering from uranium mining on their lands:
Many Navajo people have died from cancer and kidney failure, which are linked to uranium contamination, due to uranium mining. Between 1944 and 1986, mining companies removed 4 million tons of uranium from Navajo land. Scientific evidence shows that uranium has been found in the dust of 85% of Navajo homes, and everyone tested, including babies, have uranium in their bodies. Some babies have concentrations of uranium that are much higher than the U.S. average.

The long-term mortality risks for Navajo uranium miners include lung cancer, pneumoconioses, and other nonmalignant respiratory diseases. The descendants of mining families also have extremely high rates of ovarian and testicular cancer.

From 1944 to 1986, nearly 30 million tons of uranium ore were extracted from Navajo lands under leases with the Navajo Nation. Many Navajo people worked the mines, often living and raising families in close proximity to the mines and mills. Today the mines are closed, but a legacy of uranium contamination remains, including over 500 abandoned uranium mines (AUMs) as well as homes and water sources with elevated levels of radiation. Potential health effects include lung cancer from inhalation of radioactive particles, as well as bone cancer and impaired kidney function from exposure to radionuclides in drinking water. Learn more about health effects of uranium and how you can avoid contact with it.

EPA maintains a strong partnership with the Navajo Nation and, since 1994, the Superfund Program has provided technical assistance and funding to assess potentially contaminated sites and develop a response.

Abandoned Mines Cleanup | US EPA.

Wyoming will be a good place for uranium mining with Republican leadership to avoid any talk or action against uranium mining. Except maybe the Indians will be getting sick and dying.

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How does this compare to coal mining, I wonder?


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Are the Wyoming mines on Indian land? The Wikipedia article makes no mention. The article on uranium mining and the Navajo mentions Wyoming as a mining location but does not associate it with Wyoming.

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Uranium ore deposits are economically recoverable concentrations of uranium within the earth’s crust. Such deposits in Wyoming are found in porous and permeable sedimentary rocks in the Powder River, Great Divide, Wind River, and Shirley basins. Additionally, there are significant uranium deposits in the western Black Hills area in northeastern Wyoming, the Little Mountain area of the northern Bighorn Range, and the southeastern Greater Green River Basin.

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I was only trying to point out that as disgraceful as the situation with the Navajo and uranium mines where they are, linking them to the Wyoming mines as you did was a bit much.

There are uranium deposits on the Powder River Indian reservation. Native American population by state shows that 2024 Wyoming is 3.48% Native American.

Mining and logging account for over 17% of the jobs in Wyoming. Which means plenty of exposure to workers and non-workers in Wyoming.

Looks like China’s way ahead of the rest of the world on that
'China continues to stake its claim as the world’s biggest proponent of new nuclear energy technology, connecting its first small modular reactor to the power grid. China Huaneng Group Co.'s 200-megawatt unit 1 reactor at Shidao Bay is now feeding power to the grid in Shandong province, the China Nuclear Energy Association said in a WeChat post. A second reactor is undergoing tests before being connected and putting the plant into full commercial operations in the middle of next year.

The plant is the world’s first pebble-bed modular high-temperature gas-cooled reactor, heating up helium instead of water to produce power. It’s a so-called fourth generation reactor, designed to shut down passively if something goes wrong – in contrast to active systems that may not be able to trigger safety measures if power fails, which is what happened at the Fukushima Daiichi accident in Japan a decade ago.’