Others have already mentioned the location between Kyiv and the Belarusian border. Another reason could be that there are huge wetlands on the Ukraine–Belarus b

Others have already mentioned the location between Kyiv and the Belarusian border. Another reason could be that there are huge wetlands on the Ukraine–Belarus border, with only a few major roads across. If Russia wants to move troops and supplies in that general region, they have to pass by Chernobyl.