The Soviet Union wanted to get ahead in nuclear technology as fast as it could to get ahead of other countries such as America, so they started to build power plants. Another reason they did this was because of how hard it is to transport minerals from the colder farther away areas of Russia. Nuclear energy was a very promising alternative.
Russian Physical Map, Ezilon.com, date unkown
Safety in a lot of these plants was very flawed, with barely any decometers for seeing how much radiation one had been exposed to, and the few that they had were very bad and cheap. It was perfectly fine to walk on top of the reactors and see the blue glow of nuclear workings. And on top of that, the Soviets lied about their nuclear reputation. They told the world that they had no major accidents and casualties, which was a lie. Casualties and accidents had happened before.
[1]Leningrad Nuclear Plant, Wikipedia, 2008.
[2]Beloyarsk Nuclear Plant, Wikipedia, 2005.
[3]Balakova Nuclear Plant, Wikipedia, 2010
In 1974, a coolant loop burst at Leningrad killing three people [1], In 1977 a meltdown of half of the fuel assemblies stored at Beloyarsk [2], and in 1985, a safety valve exploded in Balakova, killing 14 people [3], and with all of these the Soviet Union just covered them up.