Steam generator removal begins at German plant

The first steam generator - measuring 20 metres in height and weighing 365 tonnes - was detached from its installation position inside the reactor building on 20 January, gradually lifted, tilted and rotated several times, before finally being placed in front of the new controlled area barrier.

Planning for the project at the Grafenrheinfeld plant began as early as 2021. Several structural modifications to the plant's reactor building were necessary for the lifting and unloading of the components.

_{(Image: Johannes Kiefer / PreussenElektra)}

"This task demanded the utmost precision and impressive engineering," said project manager Burghard Lindner. "Thanks to months of preparation, the actual lifting operation was carried out smoothly in approximately 9 hours. Our experienced partners Framatome and Mammoet, who had already removed the four steam generators at the Unterweser nuclear power plant, also mastered this challenge at the Grafenrheinfeld plant."

The component will be moved out of the controlled area and then made ready for transport on the power plant grounds. The removal of the remaining three steam generators will follow. The plan is to move the last of the four steam generators out and place it on the site by the end of February.

In spring 2027, the four steam generators will be shipped to Cyclife in Sweden, dismantled on site, and then partially melted down. Cyclife, a subsidiary of France's EDF, specialises in the decommissioning of nuclear power plants and waste management. In 2021, the company was awarded the contract by PreussenElektra for the dismantling and disposal of a total of 12 steam generators from the Unterweser, Grafenrheinfeld, and Grohnde nuclear power plants.

_{(Image: Johannes Kiefer / PreussenElektra)}

Steam generators are the heat exchangers in pressurised water reactors (PWRs), producing the steam that turns the turbines to generate the electrical energy in the generator. PreussenElektra said the dismantling and disposal of the steam generators is one of the key projects in the dismantling of its PWRs and will take more than a decade.

The 1275 MWe (net) PWR at Grafenrheinfeld achieved first criticality in December 1981 and was connected to the grid in the same month. It entered commercial operation in June 1982.

In August 2011, the 13th amendment of the Nuclear Power Act came into effect, which underlined the political will to phase out nuclear power in Germany. As a result, eight units were closed down immediately: EnBW’s Phillipsburg 1 and Neckarwestheim 1; EOn's Isar 1 and Unterweser; RWE's Biblis A and B and Vattenfall's Brunsbüttel and Krümmel. As part of the 13th amendment to Germany's Nuclear Power Act, Grafenrheinfeld lost its authorisation for power operation and was finally shut down on 27 June 2015.

PreussenElektra applied for the decommissioning and first dismantling permit for Grafenrheinfeld in 2014 and received it in 2018. In this first approval procedure, the company described in detail the concept for the entire dismantling of the system and the measures planned for this. PreussenElektra split the application for the individual dismantling scopes into two steps. The dismantling of the plant began in April 2018 with the granting of the decommissioning and dismantling permit. The second dismantling permit, which was granted in December 2022, for which the application was submitted in December 2019, includes the dismantling of the reactor pressure vessel and the biological shield surrounding it.