Pax romana is the answer to your question. It was period of prosperity for Rome
The radioactive materials released by the accident had many immediate harmful effects on plants and on living things such as nature and animals within 20 to 30 km of the Chernobyl power plant at the time of the accident.
So they could mainstain a stronger colonie and become a better empire
So sorry but I'm not answering your question cause I really didn't come here to help people, you see I'm a chaotic evil, so I'm pretty sure I'll just go around this website doing the same thing to other people that I'm doing to you. While getting answers myself.