As long as you want. I think the question you are trying to ask is "How long can you stay in Chernobyl without dying?".
How_long_will_the_radiation_at_chernobyl_last
14 weeks
Radiation will stay in the Chernobyl area for the next 48,000 years but humans may begin repopulating the area in the next 600 years or so. The experts predict that by than the most dangerous levels of radiation will have disappeared or been sufficiently diluted into the air, soil, and water.
See the link given below
25 years in April 2011
Yes, Chernobyl is a city.
Alla Yaroshinska has written: 'Chernobyl' 'Chernobyl' 'Chernobyl, the forbidden truth'
No, Chernobyl is abandoned
Chernobyl Heart was created in 2003.
No. Chernobyl is in Russia.
At the power plant at Chernobyl in the Ukraine
Chernobyl is in the country of Ukrain.