As long as you want. I think the question you are trying to ask is "How long can you stay in Chernobyl without dying?".
It was a health hazard immediately
Russia, the nuclear plant was in the place called chernobyl :)
I think the Chernobyl accidence happened immediately, but Fukushima happened take I think 2 days
That is in Ukrainia.
The cleanup and containment efforts following the Chernobyl disaster, which occurred in April 1986, took several years and involved extensive measures. Initial decontamination and emergency response efforts lasted for about a year, but ongoing cleanup and remediation work continued for decades. The Chernobyl Exclusion Zone remains in place today, reflecting the long-term nature of the disaster's impact. Full decommissioning of the site and surrounding areas is projected to take several more decades.
See the link given below
It is estimated that it will take around 20,000 years for the area around Chernobyl to return to normal background radiation levels. However, the most dangerous radioactive isotopes decay much more quickly, significantly reducing radiation levels within the first few decades after the accident.
no
25 years in April 2011
It was in the Ukraine, however it affected many countries across Europe and the world
Yes, Chernobyl is a city.