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Insight Web Extra

March 2009—On March 28, 1979, a combination of equipment failure and the inability of plant operators to understand the reactor’s condition culminated in the accident at Three Mile Island Unit 2 in Pennsylvania. Fuel in the reactor was heavily damaged, but the plant’s multiple safety systems, including the massive containment building, worked effectively. There were no adverse impacts on public health and safety. TMI Unit 2 was permanently shut down, the damaged fuel was removed, and the reactor is in monitored safe storage.

There were no public health or safety consequences from the TMI-2 accident

• Although a small amount of radiation was released from the reactor, no injuries, deaths or direct health effects were caused, according to more than a dozen epidemiological studies performed after the accident.

• Due in part to lessons learned and implemented industrywide after the TMI accident, U.S. nuclear plant performance has steadily improved since the late 1980s, with plants operating at higher levels of safety, reliability, efficiency and productivity from year to year. The industry’s average capacity factor—a measure of efficiency—has risen from 63 percent in 1980 to more than 91 percent in 2008.

• The accident brought about major changes in reactor operator training, plant operating experience sharing, emergency response capability, radiation protection, and many other areas of nuclear plant design, operations and maintenance.

• The Institute of Nuclear Power Operations in Atlanta was formed nine months after the accident to drive operational excellence, open communication and continuous improvement among all U.S nuclear plant operators.

• Fifty-one U.S. reactors (almost half of those operating in the U.S. today) were built in the years following the accident. Five  are in Pennsylvania. They helped make nuclear energy one of the nation’s largest sources of electricity and help provide the diversity of supply that strengthens U.S. energy security.

Read more about the accident and the lessons learned from it here.

Read NEI CEO Marv Fertel’s March 24 statement to the U.S. Senate Clean Air and Nuclear Safety Subcommittee here.

—Read more articles in Nuclear Energy Insight and Insight Web Extra.