Just back from 3 days in Kiev and 4 days in The Zone. Was my 4th visit and probably my favourite so far. Missing it already and likely to be back next October. Group I go with visit March and October every year.
Radiation levels are mostly safe. There are areas that are higher than normal but nothing that is likely to hurt you long term. There are certain things (the claw, fireman clothing) that is still hot and shouldn't really be touched.
Kiev is a great place. Lots to do and see. Subway is an experience being the deepest in the world - the escalators are beasts!
Everything is dirt cheap, people are generally quite friendly if a little abrupt but that is their way and not meant to be taken personally. Ukraine society might not be the same as western europe but is not quite the oppressed hell hole our governments would have you believe. They are actually quite a civilised bunch of people who have unfortunately been shafted by whichever country as occupied them over the years.
Regarding the Zone visit, we had 3 long days - taking the 7.40am train with the work force from Slavutych to the reactors and then taking a bus to visit certain areas, eating in the canteen and then back home on the 8.40pm train. The last day we finish early as we have traditional Ukrainian meal in the evening. This tour was easily the most intense as visited many places - Duga, Reactor 5, Jupiter Factory, Summer Camp, Yannov Station. Plus hours and hours in and around Pripyat. Got the fly the Mavic pretty much where I wanted except Reactor 5 as it's actually privately owned. Flew through the spindles on the ferris wheel which was an achievement unlocked moment. Lots of footage to get through Climbed nearly to the top of Duga - didn't like the last ladder so chickened out.
It's a fantastic experience and would recommend it to anyone.
Duga
Swimming pool selfie