The Seabrook Nuclear Power Plant, more commonly known as Seabrook Station, is a nuclear power plant located in Seabrook, New Hampshire, United States, approximately 40 miles (64 km) north of Boston and 10 miles (16 km) south of Portsmouth. It has operated since 1990. With its 1,244-megawatt electrical output, Seabrook Unit 1 is the largest individual electrical generating unit on the New England power grid. It is the second largest nuclear plant in New England after the two-unit Millstone Nuclear Power Plant in Connecticut.

Two reactors were planned at Seabrook but the first unit did not begin full operation until 1990, a full 14 years after the construction permit was granted, and the second unit was never built due to construction delays caused by protests, cost overruns, and troubles obtaining financing. The difficulties led to the bankruptcy of Seabrook's utility owner, PSNH. Since 2002, Seabrook Station has been owned and operated by NextEra Energy Resources.

In 2010, Seabrook Station applied to have its operating license extended from 2030 to 2050.^[20] In September 2012, Massachusetts Reps. Edward Markey and John F. Tierney filed H.R. 6554, titled the "Nuclear Reactor Safety First Act", which would have prevented nuclear plants from receiving license extensions from the Nuclear Regulatory Commission (NRC) if they applied more than 10 years before their licenses expired.^[21] The legislation was specifically aimed at Seabrook Station's license extension, but the bill never proceeded out of House Committee.^[22]

During the relicensing process, there were safety concerns pertaining to concrete degradation at the plant due to alkali–silica reaction (ASR) because of ground-water infiltration into various structure foundations, which prompted concerns from various local politicians.^[23] In June 2017, NRC officials "reviewed numerous documents and inspected the plant as it gauge[d] NextEra's safety plan to monitor and manage the alkali-silica reaction phenomenon present in concrete throughout the power plant".^[24] In October 2017, federal regulators allowed the non-profit nuclear watchdog group C-10 to weigh in on the license amendment request.^[25]

On March 12, 2019, the NRC announced it would be renewing the operating license of Seabrook Station for an additional 20 years, expiring on March 15, 2050.^[26] Following the license extension announcement, the group C-10 filed an emergency petition to the NRC in an attempt to prevent any license extension until further hearings on ASR were held, which was denied by the NRC in July 2019.^[27] In August 2020, the NRC's Atomic Safety and Licensing Board (ASLB) formally accepted Seabrook Station's concrete monitoring program for ASR concerns.^[28] However, additional monitoring conditions were imposed by the Board in the plant's license, citing that they are "necessary to provide adequate protection of public health and safety".^[29]

In May 2021, U.S Senators Elizabeth Warren and Ed Markey, both from Massachusetts, sent a letter to the NRC expressing concerns with the ASLB's decision and that the NRC should "reopen the record for consideration of supplemental testimony and strengthen the four license conditions in the ASLB’s Initial Decision."^[30]

In 2013, the Nuclear Energy Institute released a study showing the positive impact of Seabrook Station on the economy and environment. Key findings are listed below.^[31]

• Seabrook Station directly employs 650 people that earn, on average, more than double the average salary of workers in Rockingham County and Strafford County
• Seabrook Station generates approximately 40 percent of New Hampshire's total electricity, and its emission-free operation helps avoid the emission of nearly 4 million tons of carbon dioxide annually, which is the equivalent of taking almost 700,000 cars off the road
• Seabrook Station contributes $535 million of economic activity locally and contributes $1.4 billion to the U.S. economy each year, and for every dollar of output from Seabrook Station, the local economy produced $1.34
• Seabrook Station's financial contributions to local environmental groups over the previous decade amounted to more than $1 million

Seabrook Station has been cited as crucial for allowing Massachusetts to comply with carbon emission legal requirements, which was also evidenced by the closure of Vermont Yankee Nuclear Power Plant in 2015 causing carbon emissions to rise in New England for the first time in five years.^[32] According to projections by ISO New England, any decrease in electricity production in the region would not be expected to be replaced by renewable energy and instead would be replaced by natural gas.^[33] According to 2011 projections, if a gas-fired power plant had been built instead of Seabrook Station, then "it would have emitted nearly 94 million metric tons of CO2 over 22 years – nearly equal to all of Arizona's CO2 emissions for the whole of 2009".^[34] As of 2020, municipal electric utilities in Massachusetts only produced 2.43% of their energy from wind and solar energy, but because of contracts held with Seabrook Nuclear Station and Millstone Nuclear Power Plant in Connecticut, the share of non-emitting energy produced by Massachusetts municipal electric utilities jumps to 38.22%.^[35]

In April 2018, the New Hampshire Office of Strategic Initiatives released the state's 10-year state energy strategy that cited "preserving Seabrook Station as a source of zero-carbon energy is the most realistic and cost-effective means of managing emissions in New Hampshire at scale".^[36] If the electricity generation of Seabrook Station was to be matched by wind or solar power, the required land "would need about 290 square miles of wind turbines or about 80 square miles of solar panels".^[34]

In 1998, a plant electrician was laid off shortly after raising a safety concern with a system wiring configuration. The Nuclear Regulatory Commission (NRC) initiated an investigation into the matter, and determined that this action was a violation involving discrimination against an employee for raising a safety concern. This event resulted in an NRC Severity Level III violation and a $55,000 civil penalty.^[38]

In 2000, one of Seabrook Station's two emergency diesel generators failed during a surveillance test. The NRC inspection report detailed the event as follows:

The failure involved the crankcase overpressurizing, resulting in lifting of the crankcase relief cover assemblies, as well as displacement of the crankcase exhauster hose. Subsequent inspection revealed damage to one of the pistons and its cylinder liner as a result of non-uniform thermal growth of the aluminum piston skirt. That growth caused scuffing, scoring, and transfer of aluminum material from the piston skirt to the cylinder liner. The heat generated by the friction (galling) between the skirt and the liner bore, coupled with the hot combustion gas blow-by, eventually ignited oil vapor in the crankcase.^[39]

The NRC determined that the above event was a White finding (an issue of low to moderate safety significance), which also "involved the failure to take adequate corrective actions to address degraded components associated with one of the two emergency diesel generators (EDG)".^[39]

In 2005, a security fence installed by a subcontracted engineering firm failed a NRC inspection and was declared inoperable, which resulted in a fine of $65,000 by the NRC since "both design of the system and testing procedures did not adhere to NRC guidelines".^[40][41]

In 2012, the southern Maine coast experienced a magnitude 4.0 earthquake during Seabrook Station's refueling outage.^[42] An "Unusual Event" emergency classification was declared, but there was no impact to the plant or disruption in refueling activities.^[43]

In 2013, Seabrook Station and the workers' union reached a last-minute contract agreement within hours of expiring that would have resulted in a lockout.^[44]

In 2014, a small electrical fire originating from an elevator motor resulted in the declaration of an "Unusual Event" emergency classification. There were no injuries, evacuations, or threat to public safety from the event.^[45]

In 2015, a Seabrook Station security guard had stuffed a rifle barrel with an ear plug and two rolled up pieces of paper, which was later found during rifle cleaning. The event prompted an NRC investigation, and the security guard was banned for three years from involvement in all NRC-licensed activities.^[46]

In 2018, a magnitude 2.7 earthquake occurred approximately 10 miles from Seabrook Station, but the earthquake did not trigger any emergency procedures or result in any signs of structural damage to the plant.^[47]

In mid-2020, Seabrook Station experienced two unplanned shutdowns due to a set of control rods unexpectedly inserting into the reactor core. In both cases, all safety systems responded appropriately with the reactor being safely shut down.^[48]

On the morning of July 12, 2022, nine of the plant's sirens were "inadvertently activated" within the plant's 10-mile emergency planning zone. The sirens within the Hampton Beach area called for the beach and surrounding beaches to be evacuated. The plant and New Hampshire and Massachusetts Emergency Management Administrations later confirmed the siren activation to be a false alarm caused by human error during routine silent testing of the plant's 121 sirens. The false alarm led to the closure of beaches in Hampton, Rye, and Seabrook.^[49][50]

In 1975, the success of the anti-nuclear movement in Germany in cancelling construction of the nuclear power plant in Wyhl began to inspire attempted occupations of the construction site for Seabrook Station.^[51] Shortly thereafter in 1976, the Clamshell Alliance was formed after the Nuclear Regulatory Commission (NRC) issued Seabrook Station's construction permit.^[52]

On August 1, 1976, 600 protesters rallied at the Seabrook Station construction site.^[51] The following year in May 1977, more than 2,000 protesters occupied the construction site, of which "1,414 were arraigned on criminal trespass charges, one of the largest mass arrests in U.S. history".^[52] The Clamshell Alliance and its protests against the construction of Seabrook Station inspired other U.S. anti-nuclear groups to form including the Abalone Alliance protesting Diablo Canyon Power Plant and the Crabshell Alliance protesting Satsop Nuclear Power Plant, among others.^[53] The song "Old Settler's Song (Acres of Clams)" has become synonymous with these events.^{[citation needed]}

However, construction of Seabrook Station continued, and many Clamshell Alliance activists became dispirited with reports of "massive burnout and dropout" following the 1977 occupation.^[54]

In September 2017, activist Steve Comley Sr. along with his non-profit "We The People" paid for an electronic billboard in Salisbury, Massachusetts, allegedly warning of the absence of an evacuation plan in the event of an accident at Seabrook Station.^[55] In January 2018, the town of Merrimac, Massachusetts, joined half a dozen other communities "calling for the Nuclear Regulatory Commission to hold a hearing on whether the Seabrook, New Hampshire, nuclear power plant's evacuation plan can be effectively implemented".^[56] In response, NextEra Energy released the following statement:

We have extensive emergency response systems in place, including numerous back-up safety systems that provide our plants with layer upon layer of both automated and manual protection. Also, we work collaboratively with local, state and federal officials on a regular basis to ensure our plans are comprehensive and effective and continue to refine. These most recent claims by 'We the People' and Mr. Comley are completely without merit. Mr. Comley has a long history of making false allegations and baseless claims against Seabrook. Independent agencies, including the Nuclear Regulatory Commission, have reviewed his claims and allegations and have found them to be without substance.^[57]

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.^[58] The 2010 U.S. population within 10 miles (16 km) of Seabrook was 118,747, an increase of 10.1 percent in a decade. The 2010 U.S. population within 50 miles (80 km) was 4,315,571, an increase of 8.7 percent since 2000. Cities within 50 miles include Boston (40 miles to city center).^[59]

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Seabrook was 1 in 45,455, according to an NRC study published in August 2010.^[60]

• Seabrook 1977 – a 1978 documentary about the protests against the plant's construction