Wylfa nuclear power station closed for five months
Reactor one was shut down on 6 January for maintenance work and the discovery of further problems has delayed re-starting the station twice.
The latest repairs are to a damaged pipe which was spotted by workers on 13 June but there are hopes to restart the plant again in two weeks.
The 43-year-old facility is planned to close later this year.
A Wylfa spokesman said no radioactive material was involved in the incidents.
He said reactor one was planned to be out of action for 100 days from 6 January, but when staff tried to restart the station during the Easter Bank Holiday it was discovered that repairs were then needed to one of the turbines and a gas circulator.
A pipe leak found on 13 June has resulted in further delays to the reactor start-up.
Following a return to service, the power station will continue to produce energy until the 30 September, with a possible extension to December 2015 if safety checks can be passed.
A second reactor at Wylfa was shut down on 25 April 2012, bringing to end 41 years of service.
There are plans for a new nuclear power station on a neighbouring site, at a cost of £8bn.
Horizon Nuclear Power want to put what are known as Advanced Boiling Water Reactors on the site, next to the ageing Magnox plant.
Source: BBC News