This first segment in a multi-part series explains that tragic accidents have driven a focus on safety at nuclear power plants. The worldwide nuclear power industry says it operates today in a "culture of nuclear safety." Protecting the population and the environment, it says, are its top priorities.
Achieving and maintaining that safety involves constantly improving reactor designs, along with rigorous training for those who operate power plants. But the lessons have been learned the hard way.
Chernobyl
Pripyat, Ukraine is a dead city. Homes, schoolrooms, playgrounds, and other places are crumbling as wild nature reclaims the land. Pripyat once had some 50,000 residents. Now they are gone, perhaps forever. Only the artifacts of their lives remain behind, rotting to dust.
Pripyat died because of the deadliest nuclear power accident in world history: Chernobyl.
Early on April 26, 1986, reactor Unit Four at Chernobyl was put through an experimental test of its cooling system. The reactor overheated and exploded from steam pressure, ripping the roof off the power plant. Nuclear radiation spewed into the night sky. And, as people slept, it spread throughout Pripyat, just north of Chernobyl.
In reactor Four, the nuclear fuel and the graphite surrounding it were on fire. Authorities sent helicopters to fly over the reactor to dump sand and other materials to try to stop the fire. But, it burned for days.
The wind carried radioactive particles from the fire over a wide area. Ukraine, Belarus, Russia. Then, Scandanavia, Britain, and other parts of Europe. As the wind shifted direction, so did the radiation.
Finally, a day and a half after the explosion, an evacuation of Pripyat was ordered. People were told they would only be gone for several days, so they left nearly everything behind. They never returned.
Despite the wide spread of radiation, Soviet officials at first said very little publicly about what happened at Chernobyl. Many people believed their leaders rather than outside reports about the disaster.
A woman stopped on the street for a television interview said, "No. No. Everything is good. We do not tell lies on our radio and television."
It was radiation detectors in other countries, many hundreds of kilometers away, that forced the Soviets to admit to Chernobyl's accident.
Thousands of people were sent to Chernobyl to clean up debris from the blast. They also built a structure, called a sarcophagus, to cover the shattered reactor and its radioactive fuel. The workers' equipment became so contaminated that it had to be abandoned. The workers became contaminated as well. Many became ill.
The Soviet government said at least 31 fatalities at the plant were directly linked to the reactor explosion. The World Health Organization (WHO) says another 2200 deaths can be expected among those who took part in the cleanup. The WHO report added that, in all, Chernobyl could result in 4,000 fatalities from cancer and other radiation-linked causes.
Radioactivity forced officials to create a 30-kilometer-wide no-habitation zone around Chernobyl, sealing off Pripyat. Still, the power plant continued to generate electricity until it was finally shut down in December, 2000.
The Chernobyl nuclear plant's Soviet-designed reactors were not encased in thick concrete structures called containment vessels that are standard in the West. At the International Atomic Energy Agency in Vienna, Nuclear Installation Safety Director Philippe Jamet stresses their importance. "The containment vessels are very, are one of the barriers. We have to protect the environment and people against radioactivity in case of an accident."
Three Mile Island
Seven years before Chernobyl, on March 28, 1979, the critical need for reactor containment vessels was proven at the Three Mile Island nuclear power plant in the eastern U.S. state of Pennsylvania. A loss of reactor cooling water due to a malfunctioning valve, coupled with operator errors, caused a partial meltdown of the nuclear fuel in Unit Two. Radioactive gases were released because of pressure in the containment vessel, but it remained intact and mostly shielded the environment from the damaged core.
Only a limited and brief evacuation was ordered by Pennsylvania's governor. Reactor Two was shut down permanently. Three Mile Island's other reactor continues to produce electricity today.
Safety standards
While the Three Mile Island incident is widely credited with making some Americans wary of nuclear power, it also compelled the U.S. nuclear power industry to significantly toughen safety and operating standards. At the trade group the Nuclear Energy Institute, Vice President Tony Pietrangelo told us, "It just caused a re-examination and a need for continuous improvement in our operations – to not get complacent, to have better training, to improve our off-site response capabilities in terms of emergency planning."
The International Atomic Energy Agency, and nuclear power operators worldwide, say safety tops their priority list, and is constantly reinforced through training and monitoring of plant operations.
The same is being said by the Atomic Energy Organization of Iran, which has completed that country's first commercial power plant at Bushehr, alongside the Persian Gulf. Construction of at Bushehr began in the 1970s but was interrupted several times by revolution and war and finally was completed with Russian assistance.
In coming segments of this series on nuclear safety, Bushehr will be examined in detail.
News
