PreussenElektra has received the second and final permit needed for the dismantling of the Unterweser nuclear power plant (KKU), while RWE Nuclear has received approval for its so-called 'sub-project 2' for the dismantling of the Lingen nuclear power plant (KWL). Both approvals were issued by the Lower Saxony Ministry for the Environment, Energy, Building and Climate Protection.

Unterweser nuclear power plant (Image: PreussenElektra)

KKU is a pressurised water reactor that started operations in September 1979 and was permanently shut down in August 2011, and KWL is a boiling water reactor that started operations in October 1968 and was permanently shut down in January 1977.

PreussenElektra applied for the decommissioning and initial dismantling permit in 2012 and received it in 2018. In this first approval procedure, it described in detail the concept for the entire dismantling of KKU and the measures planned for this purpose. The company divided the application for the individual dismantling scopes into two stages. The newly granted second dismantling permit, for which the application was submitted in 2018, includes the dismantling of the reactor pressure vessel and the biological shield surrounding it.

"Receipt of the second and thus last dismantling permit for KKU shows once again that we are putting our goals for the dismantling of nuclear power plants into action," said PreussenElektra Chairman Guido Knott. "Because the dismantling is only feasible on the basis of permits, we have put a lot of effort into the multi-year approval procedures."

Since the beginning of the dismantling of KKU, the fuel rods have been removed, more than 90 systems have been shut down and around 2000 tonnes of material have been dismantled. This material is dismantled, cleaned and measured several times in a treatment centre built in the reactor building of the plant. The installations of the reactor pressure vessel have already been completely removed as part of the first mining permit.

PreussenElektra GmbH is a subsidiary of German utility EOn It is responsible for operation and decommissioning of the EOn's nuclear assets.

RWE Nuclear has announced that it received approval for KWL on 22 July. The plant was shut down in 1977 and has been undergoing dismantling since 2015.

"The dismantling of the KWL has been in full swing for several years," said Nikolaus Valerius, chief nuclear energy officer of RWE Power AG and technical managing director of RWE Nuclear GmbH. "The approval now granted is another important milestone in the final dismantling phase of the plant. We are fulfilling our obligation to safely and immediately dismantle in accordance with the Atomic Energy Act," he added.

The dismantling of KWL is roughly divided into two sub-projects. The first includes various dismantling measures in different parts of the building, the material of which is predominantly contaminated (superficially came into contact with radioactivity). These essentially include the reactor auxiliary systems or the steam converters.

"We are on the right track with this project," said KWL Plant Manager Andreas Friehe. "The expansion of steam converters is progressing rapidly. As announced previously, the further disassembly and processing of the components will take place in an external processing facility in Sweden. We are planning a corresponding transport for the autumn of this year," he added.

The now approved second sub-project - which was applied for in November 2017 - is primarily concerned with the dismantling of activated components, such as the reactor vessel with its internals and the biological shield. These will be dismantled at the plant and then packed and transferred to BGZ Company for Interim Storage (BGZ Gesellschaft für Zwischenlagerung mbH)  for interim or later final storage. By the mid-2020s, the KWL is to be released from the scope of the Atomic Energy Act, so that the complete, "conventional" dismantling can then take place.

RWE Nuclear GmbH has encompassed all nuclear energy activities of the RWE Group since early 2018.

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.

Researched and written by World Nuclear News