Germany’s Grafenrheinfeld NPP (KKG – Kernkraftwerk Grafenrheinfeld) has completed cleaning and emptying work on the fuel assembly basin achieving a dismantling milestone known as “water free,” owner/operator PreussenElektra announced. This means that the essential water-bearing systems, mainly the reactor and fuel storage pool, have been emptied and the water has been treated and released.

The reactor basin had been cleaned and emptied by the end of 2022 after the internals of the reactor pressure vessel (RPV) had been dismantled and packaged. Work on clearing the fuel storage basin began in early 2023. The basin, which is some 14 metres deep, was emptied and cleaned in stages.

“With this milestone we have now completed almost half of the nuclear dismantling of KKG,” said plant manager Bernd Kaiser.

Preparations are already underway to deal with the next large component – the dismantling of the 400 tonne RPV. This is scheduled to begin in November and will take around eight months.

The single unit KKG, with a 1,275 MWe (net) pressurised water reactor, operated from 1982 to 2015. It is located in the rural district of Schweinfurt, which forms part of the Lower Franconia region of Bavaria. It was closed in line with Germany’s decision to phase out nuclear power, taken in the wake of the 2011 Fukushima accident in Japan. Germany closed eight units immediately: EnBW’s Phillipsburg 1 and Neckarwestheim 1; E.ONs Isar 1 and Unterweser; RWE's Biblis A & B and Vattenfall's Brunsbüttel and Krümmel. E.On’s Grafenrheinfeld lost its authorisation for power operation and was finally shut down in June 2015. It was subsequently transferred to PreussenElektra for decommissioning and dismantling.

Under the first permit, granted in 2018, fuel elements were removed from the plant as well as 12,100 components and around 3,100 tonnes of material were dismantled, cleaned and treated. The RPV internals were also removed. The second permit was granted in December 2022 and will cover the dismantling of the RPV and the biological shield surrounding it.

Also in August, PreussenElektra reported that demolition work had begun on the former administration building of the Stade NPP (KKS – Kernkraftwerk Stade). KSS was closed in 2003 for economic reasons and decommissioning is now in the final stages. In the coming weeks and months, all of the buildings around the machine house will be gradually demolished, including the operations building workshop and the emergency diesel building, as well as the switchgear building and the machine house itself in spring 2024. “This will conclude the first phase of conventional demolition. In the second phase, the spherical reactor building and the auxiliary facility building will be demolished,” the company said. Dismantling should be completed in 2026, and PreussenElektra is now developing a project for the future use of the site.

Image: Grafenrheinfeld's empty fuel storage pool (courtesy of PreussenElektra)