One of the largest concerns of the general public towards nuclear energy is that of safety, both of the plants themselves and of the toxic waste they generate. Accidents at nuclear plants have captured worldwide attention for the potential dangers of nuclear energy. There have been four notable reactor accidents in the 50-year history of civil nuclear power (Three Mile Island, Chernobyl, and Fukushima are the three major accidents most frequently discussed):

  • Three Mile Island (USA, 1979) where the reactor was severely damaged, but radiation was contained and there were no adverse health or environmental consequences.[1]
  • Chernobyl (Ukraine, 1986) in which a flawed reactor design operated by inadequately trained personnel resulted in a steam explosion and fires that released at least 5% of the radioactive reactor core into the atmosphere. Two plant workers died on the night of the accident and an additional 28 people died within a few weeks due to acute radiation poisoning.[2]
  • Tokaimura Criticality Accident (Japan, 1999) resulted in three workers receiving high doses of radiation in a small Japanese plant that was preparing fuel for an experimental reactor. The accident “was caused by brining together too much uranium enriched to a relatively high level, causing a criticality (a limited uncontrolled nuclear chain reaction).”[3] Approximately 119 people received a radiation dose of over 1 mSv from the accident. The three operators’ doses were above permissible limits, and two of the doses were fatal.[3]
  • Fukushima Daiichi (Japan, 2011) occurred when a tsunami disabled the power supply and the cooling of three reactors causing a nuclear accident. All three cores melted significantly, with a fourth reactor also written off due to damage. No deaths or radiation cases were recorded due to the accident.[4]

The evidence over six decades shows that nuclear power is a safe means of generating electricity. The risk of accidents in nuclear power plants is low and declining. A major concern in nuclear power plants is the safety of the operating personnel. Radiation exposure is lowered by the use of remote handling equipment for various operations in the reactor core.[5]

The Technology Roadmap for Generation IV Nuclear Energy Systems recommends that safety be the first consideration in the design and operation of nuclear reactors. In addition to robust and easily understood safety features, on-site emergency response teams and emergency plans for every situation are recommended.[6]

Updated by Kristin Stiner, November 2020