The Temelin nuclear plant was shut down on Tuesday night because of an apparent problem with a power-generating turbine. A spokesman said technicians were investigating a possible leak in the Unit 1 turbine, which has been plagued with technical problems since the plant was launched in October 2000. The spokesman said the latest hitch posed no danger to the public and did not affect the plant's two nuclear reactors. The shutdown comes just two days after government regulators approved a request to graduate the first unit from the "testing" stage of operation to the "trial" stage. Last month, regulators approved the test start-up of Unit 2.