RBMK-1000

The RBMK-1000 was the Soviet workhorse of the 1970s and 80s: 17 units in Russia, Ukraine and Lithuania. Its huge graphite core and pressure tubes let it be built with conventional heavy industry and produce plutonium if needed.

After the Chernobyl 4 accident in 1986 all of them were modified: higher enrichment, fixed absorbers, redesigned rods and a fast shutdown system. Ignalina in Lithuania closed in 2009 as a condition of joining the European Union. Seven remain in Russia, at Leningrad, Kursk and Smolensk, with staggered closures through 2035.