If you mean when will Chernobyl be completly save - the half-life of Plutonium 239 is 24,000 years. Perhaps we should just say, "not in our lifetimes."
Valery Legasov in Chernobyl, Season 1 Episode 3Comment
The accident is well under control.
Mistakes, Nuclear EnergyViktor Bryukhanov in Chernobyl, Season 1 Episode 1Comment