Putin has backed himself into a corner. The only way the Russian government seems to be willing to move forward is to control the narrative, and so far that has been spinning a false narrative about liberating Ukraine from Nazis. At this point the information curtain is dropping in full force inside the country with extreme laws being put in place punishing "lies" about the way with up to 15 years imprisonment plus cutting off external media and social media.
Chernobyl has been in Russian control since the second or third day of the war. Strategically it is a pathway between Kyiv and Russia. I doubt Russia wants to destroy it, it'll do way more harm to Russia than anyone else, but this is a war and infrastructure is being destroyed.