By Margaret Evans
Think ‘Chernobyl’ and pictures of the nuclear meltdown from hell spring to mind. In the quarter century since, surprising things have been happening in the exclusion zone around the Ukraine’s notorious nuclear power plant. Plants and animals have returned and in some areas are thriving. But the region screams many vexing questions, none the least of which is the reason for the gradual disappearance of Przewalski’s horses that were released into the area in the late 1990s. And you have to question why an endangered species was released into such a hazardous area in the first place.
On April 26, 1986, a systems test at Reactor 4 of the Chernobyl Nuclear Power Plant near the city of Prypiat and close to the border with Belarus went catastrophically wrong. Following a sudden power surge, an emergency shutdown failed and a second more extreme power surge led to a reactor vessel rupture, then a series of explosions.
The 1000 tonne sealing cap blew off the reactor and its graphite moderator was exposed to the air, causing it to ignite. The fire raged for nine days spewing huge quantities of radiation into the atmosphere that spread 150,000 square kilometres over the Ukraine, Belarus, and Russia. The wind carried radiation fallout as far away as Scandinavia. Later, a concrete sarcophagus was built over the damaged reactor to cover the contaminated remains. But construction was poor; the roof leaks and rain drains through the floor to spread contaminated water into the surrounding soil.
The exclusion zone was established very soon after the disaster and initially extended 30 kilometres around the plant. But its border was adjusted to accommodate areas of high concentration. The zone’s area is unevenly polluted and those regions most intensively affected were initially created from the fallout from wind and rain, and then because they were the sites for numerous burials of materials and equipment used in the cleanup. More....