The main control room at Sizewell A near Leiston in Suffolk has been shut down.
The nuclear reactors were controlled from there and it has been manned 24 hours a day since 1966.
The site generated enough power to heat one trillion kettles over its 40 years but the decommissioning process is now continuing apace.
Tim Watkins, Site Director, said: "For us it will be about 10 years before we can walk away from this site and either completely de-man it or leave one or two people on the site.
"Then after 85 years the buildings, which will just be the reactor buildings, will then be taken completely apart."
Sizewell B power station in Suffolk has been taken out of service while planned refuelling and maintenance work is carried out.
More than a thousand specialists have been brought in to join the current workforce at Leiston for the next six weeks.
The so-called "outages" take happen every 18 months and are planned in advance with the National grid to make sure there is no risk to the electricity supply.
One of the biggest projects will be to change the rotors on one of the turbines which converts steam into electricity to power 2 million homes.
Nuclear energy chiefs have unveiled an Emergency Response Centre at Sizewell in Suffolk.
The £180 million project will become fully operational in March.
It will enable operators to control the station remotely, in the event of a major emergency.
For decades people have been living under the shadow of the nuclear power plants at Sizewell in Suffolk.
Today, revised plans have been published, detailing how emergency services would react in a nuclear disaster.
The plans have to be reviewed every three years, and this is the first time, since the disaster at Fukushima in Japan.
Click below to watch a report from ITV News Anglia's Serena Sandhu
A revised plan has been published today on how towns and villages surrounding Sizewell power station, will be protected in the event of an emergency.
Suffolk County Council has made the changes following the disaster at Fukushima in Japan.
The draft plan has been updated following comments from local people and community groups and the Suffolk Resilience Forum are now asking for interested parties to comment on the draft proposals before 14 November.
Changes detailed in the plan include:
•Widening the availability of prior information of what to do in an emergency beyond the current 2.4km Detailed Emergency Planning Zone.
•Updating the evacuation arrangements to include all of Leiston.
•Placing additional radiation detectors around the Sizewell site.
The entire draft plan can be viewed here.
The Sizewell B nuclear power station in Suffolk is back online after being refuelled.
It's shut down every 18 months for refuelling, which involves bringing around 1,200 specialist workers to the site.
Sizewell B has been generating enough power for more than two million homes since it started operating in 1995.
The nuclear reactor at Sizewell B power station in Suffolk is due to be restarted this week, after it was shut-down for routine re-fuelling and maintenence work.
The power station produces enough electricity for more than two million homes.
Its pressurised water design is the only one of its kind in the UK.
The nuclear reactor at Sizewell power station in Suffolk has ben shut down.
The plant produces enough electricity to supply two million homes. It's being taken off-line for 6 weeks while engineers carry out work to remove spent fuel rods and replace them with new ones. Serena Sandhu reports.
The nuclear reactor at Sizewell power station in Suffolk is being shut down today. The plant produces enough electricity to supply two-million homes.
It is being taken off-line for six weeks while engineers remove a third of the reactor's spent fuel rods and replace them with new ones.
Plans for a new nuclear power station at Sizewell in Suffolk are a step closer this morning after a similar project was given the go-ahead in the West Country.
EDF Energy wants to build a multi billion pound European Pressurised Reactor on the Suffolk coast. Plans for a similar project at Hinkley Point in Somerset have now been approved.
If it is built EDF Energy says the new Sizewell project would produce enough electricity to power one fifth of the homes in the UK.