Which events are among the three significant accidents in commercial nuclear power plants?

• A. Three Mile Island, Chernobyl, Fukushima.
• B. Windscale, Three Mile Island, Fukushima.
• C. Chernobyl, Windscale, Chalk River.
• D. Fukushima, Saint-Laurent, Davis-Besse.

Answer: (A)

These events are the three most significant accidents in the history of commercial nuclear power. Three Mile Island in the United States (1979) marked a partial core meltdown that led to major reforms in operator training, safety culture, and regulatory oversight. Chernobyl in the Soviet Union (1986) was a catastrophic reactor explosion and core meltdown with a large radioactive release, driving sweeping changes in reactor design, containment, and international safety standards. Fukushima Daiichi in Japan (2011) occurred after a tsunami knocked out cooling and power, causing multiple meltdowns and prompting a global reevaluation of nuclear plant resilience to natural disasters and severe accident management.

Other options include events that either happened at non-commercial facilities or are not part of the commonly cited trio of major commercial-plant accidents, such as Windscale (a fire at a plutonium-production facility, not a commercial reactor) and Chalk River, Saint-Laurent, or Davis-Besse, which are notable but not part of the same three-significant-accident grouping.