The disaster of Chernobyl was huge. However Russia is not the only nation which has suffered from nuclear power disasters although theirs is the worst in magnitude that has been publicised to date.
Three Mile Island in 1979 was as I recall the worst nuclear power accident in the USA. That disaster took some 14 years and $1bn to clean up although thankfully, reported increases in illness attributed to the disaster there were small though still significant. The Japanese nuclear power station at Fukushima was disastrously affected by a terrible tsunami/earthquake in the region as recently as 2011. That is recorded as being the second worst disaster after Chernoblyl
The worst case nuclear accident in the UK was in 1957 at Calder Hall.
Indeed my late father who was in the RAF and knowledgeable from his career about nuclear issues, changed the name of the house the family had just acquired, from Calderwood to simply number 18, so disastrous that accident was. Indeed, the name Calder Hall itself was changed to Sellafield presumably for similar reasons. The Guardian newspaper reported some sixty years later:
It says something for how Britain's nuclear establishment worked from the start that when Windscale No1 Pile caught fire in October 1957, it was hushed up so well that even with 11 tons of uranium ablaze for three days, the reactor close to collapse and radioactive material spreading across the Lake District, the people who worked there were expected to keep quiet and carry on making plutonium for the bomb. This was Britain's worst-ever nuclear accident...But we also know from the interviews that it was largely thanks to the courage of deputy general manager Tom Tuohy that the Lake District is still habitable today. When all else had failed to stop the fire, Tuohy, a chemist, now dead, scaled the reactor building, took a full blast of the radiation and stared into the blaze below.
"He was standing there putting water in and if things had gone wrong with the water – it had never been tried before on a reactor fire – if it had exploded, Cumberland would have been finished, blown to smithereens. It would have been like Chernobyl... there was contamination everywhere, on the golf course, in the milk, in chickens… but it was quickly forgotten about," says McManus.
Reverting to Chernobyl which was sadly, a far worse accident than Three Mile Island or Calder Hall, the BBC reports that