Three cubic meters of radioactive water escaped from the Czech nuclear power plant Temelin, said the plant's spokesman Milan Nebesar.
Over the weekend, the leak came from the main circuit pipe in the second block of the plant, located in the south of the country, 60 kilometers (36 miles) from the Austrian border.
"This is nothing serious," the spokesman said, who explained that the leak happened in a specially-fitted pipe.
The block has been closed until a faulty transformer is replaced. "The nuclear reaction has been stopped for a few days and we expect its relaunch in mid-June," Nebesar said.
"A fault in the airtightedness" caused the incident, which happened inside a zone controlled by a special floor fitted for such a type of leak, said Zdenek Prouza, spokesman for the Czech Office of Nuclear Safety.
The incident was first revealed by the Upper Austrian regional government on Monday, according to AFP.
Nebesar said the plant, operated by Czech power company CEZ, had 78 hours to give information following any minor incident at Temelin under a bilateral agreement established between the Czech Republic and Austria.
The plant, which was begun in the mid-1980s under the communist regime, has been controversial since its launch in 2000 with nuclear-free Austria campaigning for its closure ever since.
Source: AFP
