radiation from plutonium bombs is way overhyped... it took 30 years for a whole nuclear reactor of shitloads of uranium that got covered in concrete to recover to the point that all the animals and plants are fully recovered in the region of Pripyat around Chernobyl

the amount of material involved that leaked before they put the sarcophagus around it was maybe a few hundred kilos of very hot uranium... a typical nuclear bomb has like ounces to pounds of plutonium in it and that simply is not going to be comparable, even if it was all iodine 131 (which it isn't)