Chernobyl The world’s worst nuclear accident
During a test, operators at the Chernobyl nuclear power plant discovered they could draw power from the inertia of their spinning turbine generator, even after the reactor had been taken offline. For how long could they do this? No one knew. Another test was ordered. In the early morning hours of April 26, 1986, that test went horribly wrong. With safety protocols bypassed and the emergency core-cooling sytem turned off, the No. 4 reactor began behaving erratically. Supervisors ignored the warning signs and ordered the test go on. The reactor became overheated, boiling the coolant water inside. When operators tried to halt the reaction by inserting all the control rods — which absorb neutrons and slow a nuclear reaction — they found the rods wouldn’t slide back into the reactor properly. The out-ofcontrol reaction ruptured reactor No. 4 and an enormous steam explosion blew the 1,100-ton concrete top off of the reactor. This, in turn, ruptured the nuclear fuel rods themselves. A second explosion then tossed 50 tons of radioactive graphite and nuclear fuel — in the form of dust — into the atmosphere and exposed reactor No. 4’s core to the open air. And to firefighters and technicians. The resulting fire burned for 10 days. Two workers were killed that night and 26 more plant employees and firefighters died from radiation burns over the next four months. Even a helicopter, dropping boron onto the out-ofcontrol nuclear core, became snagged on the guy wire of a construction crane and crashed. Another big error: Authorities waited 36 hours before evacuating the area. 115,000 area residents were whisked away on buses. Eventually, the Soviet government resettled 220,000 people.
Once the fire was extinguished, technicians began building what what they called “a sarcophagus” to contain the still-exposed reactor No. 4. That structure was completed six months later. A new 31-ton, $3 billion arched covering called the New Safe Confinement structure is now being built nearby and will be moved into place over the reactor and sarcophagus via rails sometime next year. The hope is that the NSC will protect the site for 100 years. Officials shut down Chernobyl’s reactor No. 2 after a building fire in 1991. They shut down No. 1 in 1996 and closed the final reactor, No. 3, in 2000. A fifth reactor was never completed. In the meantime, interest has risen in the nearby town of Pripyat, which was evacuated so quickly in 1986 and is pretty much a ghost town today. Most residents were never allowed to come back for their belongings. As the danger of radiation has subsided, people have been allowed to visit the area. In 2011, the village — or, at least, parts of it — officially became a tourist area.
Thirty years ago Tuesday, a reactor at a Soviet nuclear power station 60 miles from Kiev exploded. Much of the radioactive core was vaporized, thrown into the atmosphere and spread across Europe. Nearly a quarter million peple were forced to resettle elsewhere from land that will be poisoned for centuries. By Charles Apple