The Chernobyl disaster was an accident.
Chernobyl disaster . Similarly , nuclear physicist Yevgeny Velikhov , < http://news.bbc.co.uk/2/hi/europe/4918742.stm > noted some 2 weeks after the accident that `` Until now the possibility of a catastrophe really did exist : A great quantity of fuel and graphite of the reactor was in an incandescent state '' That is , all the nuclear-decay heat that was generated inside the uranium fuel ( heat which would normally be extracted by back-up coolant pumps , in an undamaged reactor ) was instead responsible for making the fuel itself and any graphite in contact with it , to glow red-hot . The Chernobyl accident dominates the Energy accidents sub-category , of most disastrous nuclear power plant accident in history , both in terms of cost and casualties . The Chernobyl disaster ( Чорнобильська катастрофа , Chornobylʹsʹka katastrofa , Chernobyl accident ) , was considered the worst nuclear disaster in history .