Chernobyl Disaster

In the early morning hours of April 26, 1986, the Chernobyl nuclear power plant in Ukraine (formerly part of the Soviet Union) exploded, creating what has been described as the worst nuclear disaster the world has ever seen.

Even after many years of scientific research and government investigation, there are still many unanswered questions about the Chernobyl accident — especially regarding the long-term health impacts that the massive radiation leak will have on those who were exposed.

Where is Chernobyl?

Located about 81 miles (130 km) north of the city of Kiev, Ukraine, and about 12 miles (20 km) south of the border with Belarus, the four reactors at the Chernobyl Nuclear Power Plant were designed and built during the 1970s and 1980s. A manmade reservoir, roughly 8.5 square miles (22 sq. km) in size and fed by the Pripyat River, was created to provide cooling water for the reactor.

The nearest town to the power plant was the newly built city of Pripyat, which housed almost 50,000 people in 1986. A smaller town, Chornobyl, was home to about 12,000 residents. The remainder of the region was primarily farms and woodland.

What happened?

The day before the Chernobyl nuclear disaster, plant operators were preparing for a one-time shutdown to perform routine maintenance on reactor number 4. In violation of safety regulations, operators disabled plant equipment including the automatic shutdown mechanisms.

On April 26, when extremely hot nuclear fuel rods were lowered into cooling water, because of the reactors' design flaws — created more reactivity in the nuclear core of reactor number 4. The resultant power surge caused an immense explosion that detached the 1,000-ton plate covering the reactor core, releasing radiation into the atmosphere and cutting off the flow of coolant into the reactor.

A few seconds later, a second explosion of even greater power than the first blew the reactor building apart and spewed burning graphite and other parts of the reactor core around the plant, starting a number of intense fires around the damaged reactor and reactor number 3, which was still operating at the time of the explosions.

Radioactive fallout

The explosions killed two plant workers, who were the first of several workers to die within hours of the accident. For the next several days, as emergency crews tried desperately to contain the fires and radiation leaks, the death toll climbed as plant workers succumbed to acute radiation sickness.

On April 27, the residents of Pripyat were evacuated about 36 hours after the accident had occurred.

By that time, many were already complaining about vomiting, headaches and other signs of radiation sickness.

Health effects

Twenty-eight of the workers at Chernobyl died in the four months following the accident, including some heroic workers who knew they were exposing themselves to deadly levels of radiation in order to secure the facility from further radiation leaks.

The prevailing winds at the time of the accident were from the south and east, so much of the radiation plume traveled northwest toward Belarus. Nonetheless, Soviet authorities were slow to release information about the severity of the disaster to the outside world.

Within three months of the Chernobyl accident, a total of 31 people died from radiation exposure or other direct effects of the disaster. More than 6,000 cases of thyroid cancer may eventually be linked to radiation exposure in Ukraine, Belarus and Russia.

Surprisingly, the overall rate of cancer deaths and other health effects related to Chernobyl's radiation leak is lower than was initially feared. Some experts have claimed that unsubstantiated fear of radiation poisoning led to greater suffering than the actual disaster.

Environmental impacts

Shortly after the radiation leaks from Chernobyl occurred, the trees in the woodlands surrounding the plant were killed by high levels of radiation. This region came to be known as the "Red Forest" because the dead trees turned a bright ginger color. The trees were eventually bulldozed and buried in trenches.

The damaged reactor was hastily sealed in a concrete sarcophagus intended to contain the remaining radiation: How effective this sarcophagus has been is a subject of intense scientific debate. Plans to construct a safer and more permanent containment structure around the reactor have yet to be implemented.

And in 2011, Ukraine opened up the area to tourists who want to see firsthand the after-effects of the disaster.

Chernobyl today

The region today is widely known as one of the world's most unique wildlife sanctuaries. Thriving populations of wolves, deer, lynx, beaver, eagles, boar, elk, bears and other animals have been documented in the dense woodlands that now surround the silent plant. Only a handful of radiation effects, such as stunted trees growing in the zone of highest radiation and animals with high levels of cesium-137 in their bodies, are known to occur.

...