Philippsburg: Both units are undergoing decommissioning
The Philippsburg Nuclear Power Plant (KKP) is located about 30 kilometers north of Karlsruhe on an island in the Rhine. We generated electricity there from 1979 to 2011 with a boiling water reactor (Unit 1) and additionally from 1984 to 2019 with a pressurized water reactor (Unit 2) - a total of over 570 billion kilowatt-hours. Both units at the site are now in the process of being decommissioned: KKP 1 since 2017 and KKP 2 since 2020.
We currently estimate that the decommissioning work, which is carried out under the scope of nuclear law, will take about ten to 15 years for each unit - calculated from the start of decommissioning in each case. Once released from nuclear regulatory oversight, both units will be nothing more than conventional industrial facilities. Decisions regarding the handling of remaining buildings - such as the demolition or reuse of office buildings - can then be made.
Decommissioning of Unit KKP 1
The decommissioning of Unit 1 in Philippsburg (KKP 1) has been underway since 2017 and has made significant progress since then: The reactor pressure vessel - the former heart of the plant - has already been completely dismantled. The dismantling of the meter-thick concrete shell of the containment vessel, which formerly surrounded the reactor pressure vessel, is well advanced. Most of the components in the turbine hall have also been removed. All spent fuel assemblies have been transferred from the plant to the state-run interim storage facility on site. From a formal standpoint, we have all the necessary permits to decommission KKP 1 until it is released from nuclear regulatory oversight.
The spherical containment vessel formerly surrounded the reactor pressure vessel and thus the heart of the plant. The dismantling of its concrete shell, which is up to 1.40 meters thick, is currently a key focus of the decommissioning work in Unit 1. The concrete is being cut into well over 1,000 individual, precisely planned segments using wire saws. The upper half of the containment has already been completely removed.
The reactor pressure vessel was the heart of the plant, formerly housing the heat-generating reactor core consisting of fuel assemblies. To clear the way for the dismantling of the 20-meter-tall, 470-ton vessel, its internal components first had to be dismantled and disassembled. This work took place underwater using remote-controlled, industry-proven tools such as band saws or circular saws. The vessel itself, with its 16-centimeter-thick steel wall, was then cut into a total of ten segments in its installed position using a remote-controlled oxy-fuel cutter. These segments were lifted out using the building crane and further cut into precisely planned sections by an industrial robot also equipped with an oxy-fuel cutter.
In the turbine hall, a generator used to convert the kinetic energy of the turbines into electrical energy for the public grid. Demolition work there is already well advanced: not only has a large portion of the turbines, through which the steam generated in the reactor was once channeled, been completely dismantled, but so has the generator. The individual components of this equipment had a combined weight of more than 500 tonnes.
Decommissioning of Unit KKP 2
Decommissioning of Unit 2 in Philippsburg (KKP 2) began in 2020. The required decommissioning and dismantling permit had already been in place since late 2019, making us the first operator in Germany to receive such a permit prior to the plant’s final shutdown.
In the decommissioning of KKP 2, the focus is currently on the reactor pressure vessel - the former heart of the plant. Previously, the primary circuit was decontaminated, the main coolant pipes were disconnected from the reactor pressure vessel, and numerous systems were permanently taken out of service. Since April 2023, all spent fuel assemblies that were previously stored in KKP 2 have been located in the state-run interim storage facility on site packaged in the containers designated for this purpose.
The first major decommissioning activity following the shutdown of KKP 2 was the decontamination of the so-called primary circuit. In this process, the radioactive layer on the inner surfaces of the pipes and components of the primary circuit was removed and extracted and collected using filters. From a radiation protection perspective, this process significantly simplifies the ongoing dismantling, disassembly, and processing of the decontaminated systems and was thus a key prerequisite for the further decommissioning of the plant.
The separation of the main coolant pipes from the reactor pressure vessel constituted the first major decommissioning step at the plant and was also a prerequisite for work on the vessel itself. A pipe-cutting machine was used to sever the pipes. As a result of the dismantling work, the primary circuit is no longer intact. The primary circuit was a central component of the plant and ensured the transport of the generated thermal energy between the reactor and the steam generators.
The former heart of the plant - the reactor pressure vessel - has already been completely gutted. The dismantling and disassembly of its internal components was carried out primarily by remote operation underwater using industry-proven techniques such as band and circular saws as well as screw and gripping tools. This clears the way for the dismantling of the vessel itself.