The V.I. Lenin Atomic Energy Station at Chernobyl first went online in 1977, when Leonid Brezhnev was the USSR's increasingly incoherent General Secretary. By the time the #4 reactor was completed in 1983, Soviet spymaster Yuri Andropov was in charge. When that reactor exploded in the wee hours of April 26, 1986, Mikhail Gorbachev had been in office for a year.
When comparing Chernobyl to Fukushima, the explosion and graphite fire are cited as a big differences that makes Chernobyl worse. But by lifting the radiation over a mile up into the air, the graphite fire did much to spare the local population -- much the same way that the winds are blowing radiation out to sea at Fukushima. As for explosions, there have been three at Fukushima: two hydrogen explosions in Reactors #1 and #4 and a third explosion at #3 that seemed much more powerful. The Nuclear Regulatory Commission reported that the explosion came from the spent fuel ponds and sent radioactive debris at least a mile away. Strangely, this event is not receiving much media attention.
When nuclear fuel -- be it in a reactor core or spent fuel cooling pond -- explodes or burns, some of the radioactive atoms or radionuclides vaporize and get carried by the wind. At Chernobyl, radionuclides also got carried by dust and in bits of the core called "hot particles". Here, hot particles coat pine needles in the first year after the disaster. Such surface contamination is the main problem in the lands around Fukushima now. I can be pretty cavalier about radioactive zones after going to Chernobyl 25 times, but I would not go to Fukushima without a respirator.
In this map of cesium contamination during Chernobyl's first year, the darkest color shows the highest levels. These are from reactor debris expelled in the initial explosion. Note the two lobes extending north and west. They contain much of the plutonium as well.
The Chernobyl clean-up required 800,000 "liquidators" who were ordered and in many cases forced to work in the zone on short tours of duty to limit radiation exposure.
All of these vehicles were used in the Chernobyl clean-up are too radioactively contaminated to ever leave.
In the early years, workers had to change into progressively contaminated vehicles as they approached the power station.
It took 90,000 liquidators to build the Sarcophagus to house the ruined 4th reactor. It is not hermetically sealed and was never meant to be. Parts of the structure are held together only by friction and it is riddled with cracks and gaps. Birds nest inside, carrying bits of radiation out. My dosimeter shows background radiation levels 90 times normal.
visitors center has a nifty model of what is inside. The
brown sphere in the middle is the reactor core. The
so-called Cascade Wall on the left is filled with
radioactive debris from bulldozing the plant's grounds. The melted fuel melded with sand and dripped like lava into the rooms below the core and hardened.