Petr Spilka, spokesman for the Dukovany nuclear plant says the problem occurred on one of the reactor's 12 fittings that regulates the flow of water. Spilka says the hot irradiated water is not leaking but the flow is higher than usual.
He said today it would take several days to fix the problem, which last occurred in the plant in 1985.
The plant had to shut down the same reactor April 1 for several days due to a pipe leaking irradiated water.