The battle for Chernobyl is a great documentary,it's on YouTube,footage from the time,interviews wth the journalist who broke the news,it's also the one they show on the bus on the way from Kiev on the trip to Pripyat,everyone on the bus had seen it before,but as you get closer to the exclusion zone,it does sort of concentrate the mind and makes you think shit,I'm going there now.
Chernobyl 3828 is not bad either,it's an ex liquidator talking of what went on,and actual footage of workers on the roof clearing highly radioactive graphite rods with "protection" of paper face masks and rubber gloves!