scheduled to reopen. (Photo/Keith Schneider)
In January, executives at Constellation Energy startled the world with their plan to restart the closed and cold 840-megawatt Unit 1 reactor at Three Mile Island nuclear power station, site of one of the most dangerous meltdowns in atomic history.
Not so long ago such news, like the specter of the ruined Unit 2 reactor core that remained after the 1979 accident in southern Pennsylvania, would have attracted more than surprise. It would have generated terror.
No longer. Nuclear energy hasn’t returned to the glorious horizons it enjoyed at its start in the 1950s, when utility executives and the Atomic Energy Commission promised it would be “too cheap to meter.” But Constellation’s announcement that Microsoft agreed to buy all of the restarted reactor’s power for the next two decades to supply its server farms was more evidence of the relevance and increasing vitality of nuclear energy in the United States and worldwide.
A global tide of financial, environmental, civic, and design trends are converging to promote reactor development on three continents. New energy-producing modular machines, much smaller and safer than the first generation’s monstrous and ticklishly sensitive reactors like the one at Three Mile Island, are on the cusp of being deployed in the United States, Romania, and other countries. As a technology that produces no climate-changing gases and uses much less water to operate, this next generation of electricity-generating reactors makes a lot of sense.
TMI Personal ExperienceThis comes from an observer and journalist whose relationship with atomic energy was up close, personal, and alarming from the start, but has moderated considerably as nuclear energy’s role in powering the 21st century has evolved.
I was a 22-year-old health-science cub reporter in Wilkes-Barre, 130 miles upstream from Three Mile Island, along the Susquehanna River, when I joined a clamorous reporting pool covering one of America’s most frightening industrial calamities.
Our job was to explain how cooling water pumps failed and valves ignored control center commands early on March 28, 1979. The overheating 960-megawatt Unit 2 reactor, which had started commercial operation just three months earlier, began generating radioactive steam and isotopes that operators vented into the atmosphere, downwind of big East Coast metro regions. The deteriorating conditions were ominously similar to those depicted in The China Syndrome, which had opened at movie theaters 12 days earlier. There were moments when it wasn’t perfectly certain that the concrete containment building surrounding the reactor would remain intact. It took most of a week for utility engineers to bring the situation under control.
Utility executives quickly closed Unit 2 permanently. Forty years later, in 2019, the end of the Three Mile Island story seemed perfectly apparent when Unit 1 also was shut down, joining the fleet of 12 U.S. reactors that have closed since 2012.
New Era Started in Michigan
But what appeared to be an inevitable transition away from energy sourced from splitting atoms has evolved into an industrial restoration unlike anything that’s occurred in the U.S. and globally. It began in Michigan in 2023 when Holtec International, the new owners of the closed 805-megawatt Palisades nuclear station in Covert, announced they would restart the reactor. State and federal governments approved over $3 billion in public funding to support the restart, which could come this October, just three years after the plant was shut down.
The company also is preparing in 2030 to install four 300-megawatt small modular reactors at Palisades that it is designing and building at the company’s plant in Camden, N.J. Earlier this year when Constellation announced the $1.6 billion reopening of Unit 1 at Three Mile Island, the restart trend gained momentum.
All the activity has not invalidated the standard and sturdy safety, cost, and waste management critiques of nuclear power. Though most facilities operate without incident, three big reactors on three continents have melted, caught fire, and been inundated by seawater with calamitous consequences. Reactors produce radioactive waste that requires permanent disposal, but political opposition in Nevada has prevented the U.S. government from opening a long-term storage facility at Yucca Mountain for decades. Mining for uranium and other metals causes water pollution, land degradation, habitat disruption and other ecological harms. And the cost of building big reactors – Georgia Power estimates $30 billion for two new reactors at Plant Vogtle that came online in 2023 and 2024 – is prohibitive.
But in the context of the water-scarce, climate-disruptive, electricity-demanding 21st century, the risk-benefit balance has clearly tipped to more nuclear energy, not less. That is especially true for the small modular reactors under development in the U.S. and around the world.
Modular Reactors Are Next
Seven years ago I spent time in Corvallis, Oregon to learn about the 50-megawatt, air-cooled reactor that NuScale Power was bringing to market. Because it is much smaller than a conventional reactor, NuScale’s machine contains much less fuel and much less energy, and therefore can be operated with much less risk. Designed as a modular unit, the reactor could be built in a factory, shipped by truck, and put in place much like an ink cartridge is clipped into a printer. Power plants could activate one reactor and generate revenue as they install the next. NuScale’s air-cooled design meant power would be generated with much less demand for water.
NuScale received its license to sell and operate its small reactor from the Nuclear Regulatory Commission in 2023. The company’s first proposal – to build a powerplant at the Idaho National Laboratory – collapsed the same year, due to the cost of construction. It is now developing its first nuclear plant, deploying six modular reactors to generate 462 megawatts, scheduled to open in 2029 in Romania.
If the project is completed it would be the fourth nuclear plant composed of small reactors. Three others operate in China, Russia and Japan. More are on the way. Competition in the sector is fierce. Over 80 designs for small reactors are under development in 18 countries, led by the U.S., Russia, China, Japan, Canada, and the United Kingdom.
Having retired nearly 800 coal-fired generators in the U.S. since 2000, and with electrical demand anticipated to increase by 40 to 50 percent – 400 gigawatts to 500 gigawatts – by mid-century, small reactors are being counted on to meet a sizable share of the new supply.
Two successive American administrations, Biden and Trump, have taken steps – part public financing, part speeding up licensing – toward that goal. President Trump on May 23, 2025 signed four executive orders to “accelerate the secure and responsible development, demonstration, deployment, and export of United States-designed advanced nuclear technologies” to increase nuclear generation to 400 gigawatts by 2050 from under 100 gigawatts today.
Constellation Energy pledges to have Unit 1 at Three Mile Island ready for operation in 2028. Among all the baffling, disruptive executive orders issued by President Trump since the start of the year, the four made public in May to speed nuclear development amount to an industrial policy that actually appears reasoned and fit for its time.
Modular Reactors Are NextSeven years ago I spent time in Corvallis, Oregon to learn about the 50-megawatt, air-cooled reactor that NuScale Power was bringing to market. Because it is much smaller than a conventional reactor, NuScale’s machine contains much less fuel and much less energy, and therefore can be operated with much less risk. Designed as a modular unit, the reactor could be built in a factory, shipped by truck, and put in place much like an ink cartridge is clipped into a printer. Power plants could activate one reactor and generate revenue as they install the next. NuScale’s air-cooled design meant power would be generated with much less demand for water.
NuScale received its license to sell and operate its small reactor from the Nuclear Regulatory Commission in 2023. The company’s first proposal – to build a powerplant at the Idaho National Laboratory – collapsed the same year, due to the cost of construction. It is now developing its first nuclear plant, deploying six modular reactors to generate 462 megawatts, scheduled to open in 2029 in Romania.
If the project is completed it would be the fourth nuclear plant composed of small reactors. Three others operate in China, Russia and Japan. More are on the way. Competition in the sector is fierce. Over 80 designs for small reactors are under development in 18 countries, led by the U.S., Russia, China, Japan, Canada, and the United Kingdom.
Having retired nearly 800 coal-fired generators in the U.S. since 2000, and with electrical demand anticipated to increase by 40 to 50 percent – 400 gigawatts to 500 gigawatts – by mid-century, small reactors are being counted on to meet a sizable share of the new supply.
Two successive American administrations, Biden and Trump, have taken steps – part public financing, part speeding up licensing – toward that goal. President Trump on May 23, 2025 signed four executive orders to “accelerate the secure and responsible development, demonstration, deployment, and export of United States-designed advanced nuclear technologies” to increase nuclear generation to 400 gigawatts by 2050 from under 100 gigawatts today.
Constellation Energy pledges to have Unit 1 at Three Mile Island ready for operation in 2028. Among all the baffling, disruptive executive orders issued by President Trump since the start of the year, the four made public in May to speed nuclear development amount to an industrial policy that actually appears reasoned and fit for its time.
— Keith Schneider