Summary
The Three Mile Island accident was a partial meltdown of the Three Mile Island, Unit 2 (TMI-2) reactor in Pennsylvania, United States. It began at 4 a.m. on March 28, 1979. It is the most significant accident in U.S. commercial nuclear power plant history. Cleanup started in August 1979, and officially ended in December 1993, with a total cleanup cost of about $1 billion (equivalent to $2 billion in 2021).
Key Learnings / Issues
- Inadequate instrumentation and training programs at the time hampered operators’ ability to respond to the accident.
- The containment building worked as designed. Despite melting of about one-third of the fuel core, the reactor vessel itself maintained its integrity and contained the damaged fuel.
- Lack of prioritisation on alarm signals in the control room; several alarms triggered at the same time, which contributed to disorientating the operators.
- The disaster served as a wakeup call for the industry, which quickly realized that an accident at any facility would adversely impact all reactor operators.
- The accident was accompanied by communications problems that led to conflicting information available to the public, contributing to the public’s fears.
Quote
“A two-pound turkey and a fifty-pound cranberry-that’s Thanksgiving dinner at Three Mile Island.”
Johnny Carson