The Chernobyl nuclear power plant accident in April 1986 was the worst nuclear power plant accident in history. During a late night safety test, reactor number 4 suffered an unexpected power surge and explosions, which released radiation 30-40 times more than the atomic bombs dropped on Hiroshima and Nagasaki. The accident exposed graphite moderator which ignited and sent radioactive fallout into the atmosphere across parts of Europe. The Soviet authorities initially attempted to conceal the scale of the accident and did not immediately evacuate the nearby city of Pripyat.

1. Chernobyl Accident by Sibel Tekmen April 1986

2. Chernobyl disaster nuclear accident near town of Pripyat April 26, 1986 Chernobyl Nuclear Power Plant Ukraine worst nuclear power plant accident in history only level 7 event on the International Nuclear Event Scale

3. The Accident 01:23 a.m. reactor 4 suffered a power increase explosions in the core dispersed large quantities of fuel and core materials into the atmosphere and ignited the combustible graphite moderator the graphite moderator increased the emission of radioactive particles, carried by smoke reactor had not been contained in any kind of hard containment vessel during an experiment scheduled to test a potential safety emergency core cooling feature

4. The Accident Cont. No. 4 reactor exploded and released thirty to forty times the radioactivity of the atomic bombs dropped on Hiroshima and Nagasaki world first learned of the nuclear accident from Sweden, where abnormal radiation levels were registered in nuclear facilities when attempt was made at the emergency shutdown, a more extreme power output occurred which led to the rupture of the vessels and explosions exposed the graphic moderator of the reactor to air and they ignited, resulting in fire sent a plume of radioactive fallout into atmosphere and area plume drifted over parts of the western Soviet Union, and also much of Europe

5. Conditions Prior to the Accident reactor was running at full power, slowly operators began to reduce the power 12 hours after, running at 50% power only one turbine needed for steam, so turbine #2 switched off under normal conditions, the test reactor would have been reduced to 30%, but Soviet electricity authorities refused to allow this because of the need for electricity elsewhere staff received permission to resume the reactor power reduction, but one operator made a mistake, instead of keeping power at 30%, he forgot to reset the controller, which caused the power to plummet to 1% operator forced the reactor up to 7%, by removing all but 6 of the control rods-a violation and reactor was never built to operate at such ow power instead of enabling the emergency shutdown, they disabled it because that would abort the test

6. Afterwards city of Pripyat was not immediately evacuated population of the Soviet was not informed of the incident until April 29 only after learning from Sweden, did Soviet union admit that accident had occurred authorities attempted to conceal the scale of accident gov. commitee was formed as announced to investigate the accident evacuation began on April 27, residents were to bring only what was necessary since the authorities said it would only be temporary and last approx. 3 days, as a result, residents left most of their belongings, which can still be found today

7. Effects fire in building and radiation led to 28deaths International spread of radioactivity Sweden Finland Belarus Ukraine and Russia spread by weather 237 people suffered acute radiation sickness, 31 died within firste three months Radioactivity to environment health effects: cancer, birth defects, radiation poisoining