Kiev - Ukraine may close down its Chernobyl plant, scene of the world's worst civil nuclear accident, by next summer, the station spokesman, Mr Serhiy Pavlovsky, said yesterday. "First Deputy Prime Minister Anatoly Kinakh has said the station will work until the summer of 2000," Mr Pavlovsky said. He said the date had been set as the deadline because that was the limit of the safe life-span of Chernobyl's only working reactor, number three.