"The reactor is shut down," a spokesman for the E.ON energy company announced just after the plant was officially taken off Germany's electrical grid at around 8:30 am (0730 GMT).
No special buttons were pushed or cables cut at the Stade plant near the northern port city of Hamburg. "It was just like for a routine maintenance check," the spokesman said.
Stade was brought into service in 1972 and was Germany's second-oldest plant after the Obrigheim reactor in the southwest, which is to be closed by
The phase-out is part of an accord wrenched from a difficult series of negotiations in 2000-2001 between Environment Minister Juergen Trittin, with backing from Chancellor Gerhard Schroeder, and Germany's industrial giants.
"In Stade, the end of nuclear power is being taken seriously," said Trittin, who planned to celebrate the move at a swank Berlin restaurant later Friday.
Celebrations were not so obvious in the town itself. The plant has paid taxes to Stade for more than 30 years and provided jobs for a number of subcontractors in the area.
The closure does not mean a loss of jobs for the 300 people working there but it could mean a move for many. Around 150 employees will remain to dismantle the plant and the rest will find jobs elsewhere with E.ON.
The job of tearing down the facility is enormous. Around 500 million euros (590 million dollars) will be spent, compared to building costs of 153 million.
A first step will be to send its nuclear power rods to France for treatment, as Germany has no means of treating waste generated from its plants, probably by 2005.
The next phase will be to physically dismantle the plant -- a job expected to be completed by 2015.
All that will remain will be a stocking facility for low and medium level radioactive material, but that will only disappear when Germany decides on a permanent storage point for its nuclear waste.
For the country's anti-nuclear movement, the real bitter fruit of the compromise on shutting down the plants is that the atomic industry still has many productive years ahead of it, perhaps up until 2020.
The rail and truck shipments of waste back from La Hague in northwest France and Britain's Sellafield will continue until 2010, even though deliveries to those facilities will end in 2005.
The consignments have often been the target of anti-nuclear activists.
On Wednesday, the latest transport arrived at a storage dump in Gorleben, northern Germany. It was held up for a few hours by what has become a dwindling number of protestors each year.
The accord also sets production quotas on plants to give them an operational life-span of 32 years, but it allows those quotas to be shifted from one station to another.
E.ON has already put that clause into action by closing Stade now, a year ahead of schedule, because the company claims it is too expensive to run.
"The real party will start when all the plants are closed," said Suzanne Ochse, from the German branch of Greenpeace. "By then, we will have twice as much nuclear waste as today and no one will know what to do with it."