The decommissioning of Swedish reactors has achieved a significant milestone.

The disassembly of a reactor pressure vessel at the Oskarshamn nuclear power station signifies the finalization of a project that involved dismantling the RPVs of four decommissioned reactors in Sweden.

Since July 2020, the UNNU Consortium, which includes Germany's NUKEM Technologies Engineering Services GmbH and Uniper Nuclear Services GmbH (UNS), has been working on dismantling the reactor pressure vessels at Oskarshamn units 1 and 2, as well as Barsebäck units 1 and 2.

In December, after the dismantling of the fourth RPV was completed, NUKEM commented: "This accomplishment signifies the successful completion of a challenging dismantling project for the fleet. UNS, as the lead of the consortium, oversaw post-segmentation and the packaging of the cut RPV components into specialized containers, while NUKEM handled the in-situ segmentation of the RPV and the removal of asbestos insulation situated between the RPV and the biological shield."

NUKEM stated that dismantling an RPV—one of the largest and most radioactively contaminated elements of a nuclear power plant—demands exceptional accuracy and adherence to strict safety regulations. The RPV was effectively sectioned into transportable pieces and made ready for final disposal.

The operation utilized cutting-edge technology, including a specially designed flame-cutting technique and innovative instruments that allowed for the secure handling of radioactive materials, guaranteeing the safety of the project team. Additional issues, such as the extraction of asbestos-containing insulation, were methodically dealt with through thorough planning and design.

Sergey Molodtsov, Managing Director of Operations at NUKEM, remarked: "By systematically implementing the lessons learned, we managed to decrease the dismantling duration by nearly 50% from the first to the fourth reactor, showcasing a significant boost in operational efficiency. The project also illustrates that even the most complex tasks can be executed successfully, in compliance with all safety and radiation protection protocols, without any incidents."

NUKEM CEO Thomas Seipolt emphasized: "The success of this highly technical and organizationally demanding project reflects the collaborative efforts of all parties involved. We express our heartfelt gratitude to the license holders BKAB AB, OKG AB, and Uniper's Swedish ND&D program, along with our consortium partner UNS, for their commitment throughout the project."

In December 2018, Uniper announced a "long-term and common strategy" for the decommissioning of the two-unit Barsebäck facility alongside units 1 and 2 of the Oskarshamn plant. Under Uniper's strategy, the radiological dismantling of the four reactors—during which all radioactive waste will be extracted from each unit—is planned to take place between 2020 and 2028. The total expenditure for decommissioning the Barsebäck and Oskarshamn units is projected at SEK 10.0 billion (USD 918 million).

The two 600 MWe boiling water reactors (BWRs) at Barsebäck, located approximately 30 kilometers from Malmö in southern Sweden, were shut down in November 1999 and May 2005, respectively. Oskarshamn 1, a 473 MWe BWR, ceased operations in June 2017, while Oskarshamn 2, a 638 MWe BWR, stopped functioning in 2013.