This is from a journalist friend of mine
Called Stefan Korshak who lives and works in Kiev. Bear in mind, he's a journalist, not a scientist :
Well if that's not a lead in I don't know what is. As it just happens, I just recently was in the Chernobyl Exclusion Zone, as periodic (get it?) visits to that place fall into my job description.
Yes the area underneath the Sarcophagus is incredibly irradiated, and will be so for some ridiculous time frame like thousands or millions of years, I forget exactly. True if you find moss or mushrooms somewhere you can get a Geiger counter to click right merrily. But it's not like the surface of Venus, the Zone's atmosphere isn't poisonous, and in most locations the radiation levels are the same as 200 km. to the south, opposite where the radioactive cloud blew. I'm told that you get more dangerous radiation lying on a beach in Turkey on a sunny day, than standing next to the Sarcophagus - again, and assuming you don't go inside of it.
There are without question some nasty half-lives on some of the isotopes in there, but as the scientists explained it to me, when thinking about how dangerous it is in the Zone you have to take Mother Nature into account. Basically, and generally speaking, a quarter-century of rain and erosion has washed a great deal of the worst hot elements into the water drainage system, where it has to a substantial extent settled and/or been silted over. I'm told the water itself in most places won't get a peep out of a Geiger counter, although it's a big territory and a lot of swamp, who can say for sure?
A simple indicator of how drainage helps control radiation are the Rad levels on the roads vs. the forest edges on either side of them. It's sort of a given the radiation on the roads is absolutely normal, while on the sides in the forest it can be five time higher and already dangerous in the same way as a tooth X-Ray is dangerous, a short exposure is no big deal but constantly over months or years and you're asking for cancer. Which makes the Zone a fairly safe place to visit, while keeping it basically uninhabitable.
The terrain is forest and fields and most of the time, if you aren't looking at abandoned villages, it's quite pretty. Very thick underbrush, lots of water, waist- and even chest-high grass in the old farm fields.
The scientists (unfortunately, because wouldn't be cool if there were) have found almost no mutants over the years as pretty much whatever the radiation mutated died at birth or shortly thereafter - this is Nature, after all. There is tons of wildlife and since only plant engineers and security and the odd thrill seeker actually goes into the Zone, and of them only a tiny percentage ever leaves the roads, the whole place is pretty much a huge nature refuge. Wolves, foxes, eagles, bison, etc. etc. I heard a rumor that even bears are coming back, they're already in Belarus. There used to be looters going into regularly, but it sort of tailed off after the new century, pretty much everything that could be stolen is long gone now.
The cooling ponds near the Sarcophagus - you know, where the spent fuel rods get parked like at Fukushima - are just filled with goldfish/carp, and big ones, I'm talking the size of your arm some of them. There is always the joke the radiation made them that way, but to hear the biologists explain it, it's just Nature doing its thing, the cooling ponds are big and flat and shallow and open and they're pretty much perfect conditions for bug larvae and whatever else carp like to eat, no natural predators and no humans either, the station crews don't fish for them because you can't eat them, see above on radiation in the sediment.
The problem with repopulating a place like Chernobyl is, I am told, not that the whole place is irradiated and hot, but rather that some spots are and some of the spots move with time, and change in degree, and keeping track of it is a major main and get it wrong and people really and truly could get hurt. Further, the place is really swampy and wet, this is the Pripet Marsh basically, so even if you cleaned up the buildings and the land, there is still the problem of the water table - again, within the realm of human capacity but not cheap or easy.
One of the engineers explained it to me this way "It's not like we couldn't decontaminate the place and repopulate the abandoned villages, it's technically possible. But our country is poor and we have plenty of land outside the Zone that isn't developed, so unless you're trying to prove something there's really no point in trying to make the Zone inhabitable. Doesn't make sense financially."
Another thing to remember is, at any given time something like 1,000 people are in the Zone living there 24/7, they're either engineers or scientists or guards or whatever, and they spend two weeks in and two weeks out. They say it's safe work, but they get paid pretty well by Ukrainian standards.