Short answers, pulled from the story.
The Experimental Breeder Reactor One generated electricity for the first time on the 20th of December 1951. This event occurred in a quiet field near Arco, Idaho, and marked the moment humanity first harnessed the atom to generate electricity. The reactor produced about 100 kilowatts of power to illuminate four ordinary light bulbs.
The USSR built the world's first nuclear power plant to generate electricity for a power grid. The Obninsk Nuclear Power Plant went online on the 27th of June 1954 and produced around 5 megawatts of electric power. This plant preceded the first commercial nuclear power station, Calder Hall, which connected to the national power grid in England on the 27th of August 1956.
As of 2019, 71% of French electricity was generated by nuclear power. This percentage represents the highest share for any nation in the world. France constructed 25 nuclear power plants over the 15 years following the 1973 oil crisis to reduce reliance on oil for electric generation.
The 1986 Chernobyl disaster in the USSR resulted in 56 direct deaths. This event is considered the worst nuclear disaster in history both in total casualties and financially, with cleanup costs estimated at 68 billion U.S. dollars in 2019 adjusted for inflation. The disaster led to the creation of the World Association of Nuclear Operators to promote safety awareness.
The half-life of reactor-grade plutonium found in spent nuclear fuel is 24,000 years. This isotope is one of the medium-lived transuranic elements that pose the most concern for countries that do not reprocess spent fuel. Spent fuel becomes less radioactive than natural uranium ore after about 100,000 years.
The Chernobyl accident and the Fukushima accident were both ranked at level 7 on the International Nuclear Event Scale. The Fukushima Daiichi nuclear accident was caused by the 2011 Tohoku earthquake and tsunami and resulted in three core meltdowns. These two events are the only level 7 accidents in the civilian nuclear power industry.