The last reactor to shutdown was Unit 3 in December 2000. The whole facility has been undergoing cleanup and decommissioning since.

https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant#...

Drifting slightly off topic but it always seemed amazing to me that they kept the other reactors running even in the immediate aftermath of the Unit 4 explosion. Literally just down the hall, units 1, 2, and 3 ran for years afterwards. These were all manually controlled reactors that needed humans in the control room. No "working from home "on these.

I think the main reason they did that, was there was simply not money in Ukraine to build replacement power plants during the 90s after the USSR collapsed. They had no other option than to keep the plant running, or risk their entire grid collapsing. Very scary to think about having to make that decision.

Unit 3 was just behind a wall, but 1 and 2 were quite far away (300-500m).

They all had multiple serious incidents before and after the Chernobyl Disaster (1982 - partial core meltdown at #1, 1984 - incidents at #3 and #4, 1991 - fire at the turbine hall of #2). This was the most unsafe nuclear power plant in the whole USSR and the operators were in grave danger all the time.

There are still 8 reactors of the same type (RBMK) active in Russia, though they have been retrofitted with changes to reduce the risk of another Chernobyl scenario.

Blacking out a good portion of the country for years while other power plants were being built probably wasn't an option if they could more or less keep the others running.