Three Mile Island accident

The nuclear meltdown at the Three Mile Island reactor in Pennsylvania began on the morning of March 28, 1979. A combination of equipment malfunctions, human errors, and misjudgments caused a partial meltdown of the reactor core in Unit 2 of the Three Mile Island Nuclear Generating Station. The incident was triggered by a failure in the secondary cooling circuit. This led to a significant release of radioactive gases. The disaster shook public confidence in the nuclear industry, leading to sweeping changes in regulatory oversight and emergency response planning. It galvanized anti-nuclear protests and contributed to a slowdown in the construction of new nuclear plants.

Just days after the initial incident began on March 28, 1979, on April 1, 1979, Pennsylvania Governor Dick Thornburgh advised pregnant women and young children within a five-mile radius of the Three Mile Island nuclear facility to evacuate. The announcement came after conditions at the plant were deemed more serious than initially believed, with potential risks of additional radioactive release. The evacuation order stemmed from heightened uncertainty around the extent of radioactivity that had been released, and it highlighted the communication and public safety issues that plagued the management of the crisis. The decision was pivotal in prioritizing public health amidst the ongoing emergency.

On December 12, 1980, the Kemeny Commission, a presidentially-appointed commission tasked with investigating the Three Mile Island accident, released its report. The report attributed the accident to a combination of equipment failure, design flaws, human error, and poor safety culture. It made numerous recommendations to improve the safety and regulation of nuclear reactors in the United States. This included enhancing emergency training, improving communication protocols, and upgrading technological systems to prevent similar incidents in the future. The report's findings and recommendations influenced nuclear policy and safety standards for years to come.

On August 29, 1983, a class-action lawsuit was settled between the residents living near Three Mile Island and the plant's operators. The lawsuit arose from claims of health impacts and property devaluation following the 1979 accident. Residents sought damages for alleged exposure to radiation and the loss in the value of their homes. The settlement represented a significant moment in the aftermath of the accident, addressing community grievances and offering compensation. Though monetary compensation was part of the settlement, the resolution did not admit any fault or liability on the part of the plant operators.

After being shut down following the 1979 accident, Unit 1 of the Three Mile Island nuclear power plant was authorized to restart on August 14, 1985. The decision came after extensive reviews and modifications to improve safety and performance. The Nuclear Regulatory Commission required the plant to implement changes in operator training, emergency procedures, and equipment reliability. The restart of Unit 1 marked an important milestone in the recovery and continuation of nuclear operations at Three Mile Island, though it remained a point of contention for those opposed to nuclear energy due to lingering safety concerns.

On April 19, 1989, the U.S. Court of Appeals dismissed remaining legal claims of health effects against the operators of the Three Mile Island nuclear plant. This decision arose from multiple suits alleging adverse health outcomes caused by radiation released during the 1979 accident. The court ruled there was insufficient scientific evidence directly linking the accident to specific health issues in the plaintiffs. This judgment underscored the challenges in proving causation in environmental and nuclear litigation, especially concerning alleged long-term health impacts from exposure to low-level radiation, and was a significant point in the legal closure of accident-related proceedings.

On September 21, 1993, it was announced that Unit 2 of the Three Mile Island nuclear power plant, the reactor affected by the 1979 accident, would be permanently decommissioned. The decision represented the end of efforts to rehabilitate or reuse the damaged reactor. Decommissioning involved placing the reactor in SAFSTOR, a long-term storage condition where the plant is monitored and maintained until it is ultimately dismantled. This process marked the final chapter in managing the legacy of the accident and ensuring that the reactor posed no future risk to public safety or the environment.

In 2009, the United States marked the 30th anniversary of the Three Mile Island nuclear accident. Observances and memorials took place to remember the event, which had a profound impact on nuclear safety and regulation. Many reflected on the lessons learned and the ongoing challenges of ensuring safe nuclear power. The legacy of the accident includes stricter regulatory controls and a greater emphasis on safety culture across the nuclear industry worldwide. It served as a reminder of the potential risks of nuclear energy and the importance of maintaining rigorous oversight and technological advancements to prevent future accidents.

On June 20, 2019, it was announced that Unit 1 of the Three Mile Island nuclear plant would close in September due to economic reasons. The plant's owners cited the lack of financial viability due to market conditions that favored natural gas and renewable energy sources, as well as competition from other power producers. The closure ended decades of electricity generation at the site and brought to a close the operations of the last reactor at Three Mile Island. The announcement highlighted the challenges faced by the nuclear power industry amid changing economic and environmental landscapes.

On September 20, 2019, Unit 1 of the Three Mile Island nuclear power plant was permanently shut down. The closure ended 45 years of operation, signaling the end of an era for the plant often associated with the 1979 accident. The shutdown was primarily due to economic challenges, including competition from less expensive natural gas and renewable energy. Unit 1's closure marked the conclusion of operations at the Three Mile Island site, reflecting broader trends in the energy sector where nuclear plants are increasingly economically unsustainable without subsidies. Decommissioning efforts were set to begin following the shutdown.