Brussels - The European Union was placed on alert Wednesday as a nuclear power plant in Slovenia sprang a leak in its cooling system.

The plant in Krsko, in south-west Slovenia, issued an alert that it had begun to spill coolant from its primary cooling system at 1738 local time (1538 GMT), a message from the European Commission, the EU executive, said.

The commission instantly informed all 27 EU member states, warning them of the situation and requiring them to inform it in turn of any anti-radiation measures they would put in place.

However, by 1930 local time, the plant had been completely shut down and experts had confirmed that all the leaked coolant had been kept within the plant by its containment system, the commission said.

"The Slovenian authorities have confirmed that there has been no discharge to the environment. The situation can be considered fully under control," the statement said.

The 696-megawatt light water reactor in Krsko, built by US firm Westinghouse from 1974 to 1984, is the only commercial nuclear plant in the former Yugoslavia. It is located near the Croatian border and supplies power to both countries.

The incident, while small in itself, is likely to re-ignite the debate over the safety of nuclear power, at a time when it is increasingly being hailed as a way to cut greenhouse-gas emissions.

Nuclear safety is a highly-sensitive subject in the EU, with several member states - notably Italy and Germany - vowed to phase out the use of nuclear power.

However, most security fears have focused not on Slovenia, but on its fellow-EU newcomer Lithuania, where the Soviet-built Ignalina nuclear plant is due to be closed down by the end of next year. (dpa)