The interior ministry said it had imposed three fines in all totalling 1.6 million euros on the Vandellos II reactor, which came on stream in 1987 and is run by electricity companies Endesa and Iberdrola.

The ministry, in acting on a recommendation by the Spanish Council of Nuclear Security (CSN), said that the fine was justified because of the "priority nature of nuclear plant security."

The serious incident in question which occurred on August 25, 2004 at Vandellos II, in the northeastern region of Tarragona, involved the rupture due to corrosion of a piping joint in the cooling system.

The fine comprised three elements: Firstly, for poor maintenance leading to the accident in the first place, then not carrying out the requisite repair work demanded by the CSN and furthermore for neglecting to point out that corrosion had been a problem since 1993.