Take the southwest paved road out of Rostok through Chemical Plant, and you'll eventually spot this big crater with anomalies around it. The entrance is actually inside that crater through an underground hole but watch out for the radiation fields, so bring those anti-rad meds with you. Once inside youll need to deal with mutant rats in the corridors, and getting the power back on is your first priority.

Good to know: the code 1976 gets you through those armored doors, and youll want to find the control rooms with voice recordings to figure out the generator situation. The whole place is crawling with hostiles so stay alert especially when installing that emitter device. After completing everything, new paths open up for a quicker exit but keep your guard up since the areas still dangerous. Definitely worth bringing extra ammo and healing items since backtracking through hostile areas isn't fun.