MADRID, Nov 8 (Reuters) - Output at Spain's 1,000-megawatt Vandellos II nuclear plant was cut to 49 percent from full power at 1425 GMT after a power surge caused overheating, a spokesman for the plant said on Saturday.
Operators reduced output after the surge sent temperatures 20 percent above the maximum allowed for the installation.
Spain's nuclear safety regulator CSN said the owners of the plant are identifying the cause of the surge, adding that the incident had no impact on the environment or plant workers.
Vandellos is 72-percent owned by Spain's second-largest electricity firm Endesa, while top utility Iberdrola has the other 28 percent.