British Energy saw its profits fall for the first quarter of 2007, following stoppages at its Hinkley Point and Hunterston stations.
British Energy saw outages at its Hunterston station
The nuclear energy firm saw net profits drop to £91m in the three months to July 1, down from £146m in the same period last year.
Unplanned losses of nuclear energy hit nearly 20% up from 13%.
Interest in nuclear energy has gained interest with the UK government examining whether to build new plants.
"We continue to work hard to deliver reliable output from Hinkley point B and Hunterston B, while seeking to maintain the performance seen across the fleet for the rest of the year," said Bill Coley, chief executive of British Energy.
While both stations are in service after outages earlier this year, they are running below full capacity.
By March 2008, the firm will decide whether to extend the life of the two stations.
The government is running a consultation on the future of nuclear power, and whether firms can invest in new nuclear energy plants.
British Energy said it was "well placed to play an important role in any new build as we have skills, experience and sites that are good candidates for any new construction".
The firm is in talks with several parties about developing such plans and has started looking at the suitability of existing sites for new projects.
Investment in plant projects, major repairs and strategic spares reached £56m for the period, an increase from £54m last year.