Yes. In general, there are a lot of radiation in the Chernobyl zone only in some places. Do not worry. You will either not fall into these places at all, or you will be there very briefly. In one day that the tour will take place, the human body will accept a radiation level corresponding to an approximate dose of 0,0005 during an X-ray scan. Approximately the same amount of gamma radiation can be obtained in three to five hours in an airplane. So there is no harm. Even when flying to Kiev, there will be more radiation.