Tuesday, 17 June 2025
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In total, all four steam generators – each measuring 20 metres in height and weighing about 300 tonnes – have been removed within four weeks, completing the project on schedule.
The actual dismantling was preceded by nearly two years of planning, testing, and implementation of the necessary modifications and additions inside and outside the reactor building, as well as the individual dismantling steps of the large heat exchangers.
PreussenElektra said the work within the reactor building to remove the steam generators was particularly challenging, with each component needing to be rotated, tilted, and gradually lifted several times before being lowered into a storage area on the plant site. It said the removal of the first steam generator in mid-May took about 18 hours, but with the experience gained from each individual lift, this time was reduced to around 11 hours for the final steam generator.
“This was absolute precision work and a masterpiece of engineering,” said Project Manager Attila Damon. “The intensive preparation paid off. Our experienced partners Framatome and Mammoet handled this task well.”
In July, the steam generators will be shipped to Cyclife in Sweden, dismantled on-site, and then melted down in a smelter.
Unterweser – a pressurised water reactor with a gross installed capacity of 1410 MWe – operated between 1978 and 2011. It was one of seven nuclear power plants shut down in Germany in March 2011 when it lost its commercial operating licence under the 13th Amendment to the Atomic Energy Act.
PreussenElektra is also decommissioning the Brokdorf, Grafenrheinfeld, Grohnde, Isar 2 and Stade PWR nuclear power plants.
In 2021, PreussenElektra awarded the contract for the dismantling and disposal of a total of 16 steam generators from the Unterweser, Grafenrheinfeld, Grohnde, and Brokdorf plants to Cyclife, a subsidiary of EDF specialising in nuclear power plant decommissioning and waste management.
Preparations for the removal of the four steam generators at the next plant, Grafenrheinfeld, are already under way, PreussenElektra said.
