One thousand extra workers will join the site’s 700-strong team during the ten-week period, providing a boost to the local economy.
The team will carry out more than 13,000 separate pieces of work – each carefully planned during the last two years of preparation.
Ian Stewart, station director at Heysham 1, said: “The team here at Heysham 1 is ready for what will be a busy time for the station and they will be supported by many hundreds of contractors.
“The shutdown brings significant benefits to the area – with many contractors choosing to stay locally during this period.”
Heysham 1’s two reactors generate enough low carbon electricity to power around two million homes, so saving around six million tonnes of carbon dioxide emissions each year.
The extensive programme of work will see inspections inside the reactor, as well as the installation of new equipment at the plant. The biggest projects include replacing two large gas circulators which help cool the reactor.
The site is also planning to carry out modifications to the reactor boiler spines, by adding some insulation material to reduce the heat in this area.
The maintenance periods, known as ‘statutory outages’, take place every three years on each reactor and are planned in advance with the National Grid to ensure that there is no impact on the national electricity supply.
Heysham 1’s other reactor is due to continue operating normally throughout the period.
The power station is due to continue operating until 2019, but is planning to operate beyond that date and life extension work is underway at present.