Concerns about the safety of nuclear power production increased greatly after a serious accident took place at Three Mile Island nuclear power plant near Harrisburg, Pennsylvania, in 1979. A breakdown of the reactor's cooling system and the destruction of the reactor's core came as a result of mechanical and human failures. A total core meltdown and a possible release of large amounts of radioactive isotopes into the atmosphere were prevented by scientists and technicians, and plant cleanup continued in 1980.
An explosion and fire in 1986 at the Chernobyl nuclear power plant near Kiev, in Ukraine - then part of the Soviet Union - was the worst nuclear accident in history. The explosion and fire tore open the reactor and released into the atmosphere large amounts of radioactive isotopes. The Chernobyl reactors - unlike most Western reactors - lacked an enclosure to prevent the escapement of radioactive isotopes. Authorities reported that thirty-one people died from radiation sickness or burns. They also reported that more than 200 other people were injured badly. Many people believe that those numbers are much lower than the true ones. The eastern part of what was the Soviet Union was covered with radioactivity, and wind carried it into northern and central Europe.
The accidents at Three Mile Island and Chernobyl caused increased opposition to nuclear power in many countries during the 1980's. The Nuclear Regulatory commission in the United States increased control of nuclear plants. "Many experts believed the safety problems could be solved, and some countries planned to expand their nuclear power facilities. Research continued to develop safer reactors, using graphite as a moderator and layers of ceramics and carbon to enclose the fuel rods. The engineers claim that such a reactor could not melt down.
Information for this post came from an article by Vera Kistiakowsky in World Book Encyclopedia, Vol. 14, p 592.