MOSCOW — Prime Minister Arseniy P. Yatsenyuk of Ukraine on Wednesday announced that there had been an accident at one of the country’s nuclear power plants, briefly setting off fears of a Chernobyl-like catastrophe. But there appeared to have been no radiation leak and only a temporary disruption in the power supply.

Mr. Yatsenyuk, during a session of the new Ukrainian government, disclosed that the accident had taken place at the Zaporizhia Nuclear Power Plant and called on the newly installed energy minister to quickly brief reporters on the incident, the Ukrainian news media reported.

The energy minister, Volodymyr Demchyshyn, said that there was “no threat” from the accident and that the malfunction had taken place in the section of the plant responsible for distributing power, not among the reactors in the section for generating power.