You've probably seen that massive concrete dome while driving along I-95 in New Hampshire. It's Seabrook Station. Most locals just call it "Seabrook," and depending on who you ask, it’s either the crown jewel of New England’s clean energy grid or a lingering symbol of 1970s-era corporate overreach.
Actually, it's both.
Seabrook Station is a single-unit Westinghouse pressurized water reactor. It sits on a 900-acre site on the New Hampshire coast. It cranks out about 1,244 megawatts of electricity. That is a massive amount of power. To put it in perspective, that’s enough to juice up roughly 1.2 million homes. It’s the largest individual electrical generator in New England. If Seabrook goes offline for maintenance, the regional grid—managed by ISO New England—literally feels the shudder.
But the story of the Seabrook nuclear power plant is messy. It's a tale of billion-dollar bankruptcies, massive protests that basically birthed the modern anti-nuclear movement, and a concrete "disease" that has engineers scratching their heads.
The Clamshell Alliance and the War for Seabrook
If you want to understand why Seabrook looks the way it does today—a lonely single dome when it was meant to have a twin—you have to go back to the 1970s. Originally, Public Service Company of New Hampshire (PSNH) wanted two reactors. They envisioned a nuclear hub.
Then came the Clamshell Alliance.
In 1977, more than 1,400 people were arrested at the site. It was one of the largest acts of civil disobedience in U.S. history. People weren't just worried about meltdowns; they were furious about the cost. And honestly, they were right about the money. The project was a financial black hole. By the time Unit 1 was finished, the cost had ballooned from an estimated $1 billion to nearly $7 billion.
It broke the company. PSNH filed for bankruptcy in 1988, marking the first time a major American utility went under since the Great Depression. Unit 2? It was scrapped. Abandoned. A skeleton of what was supposed to be. That’s why when you visit the site today, you see a lot of "extra" space and infrastructure that feels slightly out of proportion for a single reactor. It's a ghost of a plan that was too big to survive.
Is Seabrook Station Actually "Green"?
This is where the debate gets heated. If you look at the data from the Nuclear Energy Institute, Seabrook prevents about 4 million tons of carbon emissions every year. That is roughly equivalent to taking 800,000 cars off the road.
New Hampshire’s carbon footprint would skyrocket without it. Period.
However, the "green" label is tricky. You have the spent fuel rods stored on-site in dry casks because the federal government still hasn't figured out a permanent geological repository (looking at you, Yucca Mountain). Then there’s the cooling system. Seabrook sucks in huge volumes of water from the Atlantic Ocean through tunnels carved into the bedrock. Even with "fish-friendly" intakes, it’s a massive industrial footprint on a sensitive marsh ecosystem.
The Alkali-Silica Reaction: A Concrete Problem
Right now, the biggest technical hurdle for the Seabrook nuclear power plant isn't the reactor core. It’s the walls.
Specifically, a condition called Alkali-Silica Reaction, or ASR. Engineers sometimes call it "concrete cancer." Basically, moisture gets into the concrete, reacts with the silica in the aggregate, and forms a gel that expands. This expansion causes micro-cracking.
Seabrook is the first nuclear plant in the U.S. to deal with widespread ASR.
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Is the building going to crumble? No. NextEra Energy, the current owner, has spent years monitoring it. They use incredibly precise instruments to measure the expansion in millimeters. The Nuclear Regulatory Commission (NRC) has given them the green light to keep operating, but it’s a point of massive contention. Organizations like C-10 Research and Education Foundation argue that the NRC is being too lenient. They worry that in a massive earthquake, the "pre-stressed" concrete might not behave the way it was designed to.
It’s a fascinating engineering puzzle. How do you fix a building that is already standing and filled with radioactive material? You don't "fix" it; you manage it. You reinforce it. You watch it like a hawk.
Why Seabrook Matters for the 2030s and Beyond
In 2019, the NRC extended Seabrook’s operating license. It can now run until 2050. That means this plant will be a cornerstone of the New England economy for another quarter-century.
The reliability factor is what keeps grid operators up at night. Unlike wind or solar, Seabrook has a capacity factor of over 90%. It’s "baseload" power. It doesn't care if the sun isn't shining or the wind isn't blowing during a January "Polar Vortex." When the temperature drops to -10°F in Manchester and everyone turns up their electric heat, Seabrook is the reason the lights stay on.
But the economics are shifting. Natural gas is cheap. Offshore wind is coming—slowly, but it's coming. The cost of maintaining an aging nuclear plant with a concrete "disease" is high. NextEra has to balance the massive revenue from those 1,244 megawatts against the skyrocketing costs of specialized inspections and security.
Navigating the Future of Nuclear in New England
If you live in the Seacoast region or you're just interested in the future of energy, you need to look past the "Nuclear: Yes or No" bumper stickers. The reality is far more nuanced. Seabrook is a massive machine that is both a climate savior and a source of long-term environmental anxiety.
Understand the Emergency Planning Zone (EPZ)
If you live within 10 miles of the plant, you are in the EPZ. This isn't just a fun fact. Towns like Hampton, Rye, and Salisbury have specific evacuation routes and siren systems. You should know your zone. The state of New Hampshire and the Commonwealth of Massachusetts maintain updated maps for this.
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Follow the NRC Inspection Reports
The NRC isn't perfect, but they are transparent. You can go to the NRC’s ADAMS database and read the actual inspection reports for Seabrook. Look for the "Integrated Inspection Reports." They detail everything from pump failures to the status of the ASR monitoring. It’s dense, but it’s the only way to get the facts without the PR spin.
Monitor the Spent Fuel Situation
Until a national solution is found, the waste stays in Seabrook. It’s stored in "Dry Cask Storage"—big steel and concrete cylinders. Many people don't realize that this waste is arguably safer in these casks than it was in the spent fuel pools, but it remains a permanent fixture of the New Hampshire coastline for the foreseeable future.
Stay Active in Local Oversight
Groups like the Seacoast Anti-Pollution League and C-10 provide a necessary counterweight to corporate interests. Even if you support nuclear power, having a skeptical, well-funded watchdog is essential for safety.
Seabrook Station isn't going anywhere. It’s a massive, humming heart in the New England power grid. Whether you view it as a relic of the past or a bridge to a carbon-free future, its impact on the region is undeniable and permanent. The best thing anyone can do is stay informed, look at the actual data, and understand that in the world of high-stakes energy, there are no easy answers.