The Brunsbüttel nuclear power plant was taken into operation about 40 years ago. It stopped generating electricity in 2007, and in 2012 Vattenfall applied for the license required for decommissioning and dismantling. Restoration of the site to greenfield condition is a process that is expected to take about 15 years in total, and Markus Willicks, power plant manager since July 2017, explains the road to reach this goal.
The permit procedure for decommissioning and dismantling commenced in November 2012, and since then a lot of documents, calculations and data have been submitted to the Nuclear Supervisory Authority. "Dismantling takes place in several phases, which partially overlap and for which we need various permits. The first permit – formally the First Decommissioning and Dismantling Permit – describes the overall activities and is a sort of roadmap for dismantling," says Willicks. "We expect to receive this first permit in mid-2018, and then we can really get started."
"An important aspect of this is continuous dialogue with all stakeholders: local residents, politicians, environmental groups, and of course all interested parties," says Willicks.
Removing spent fuel elements
This does not mean that only paperwork has been done up to now – far from it. "In preparation for dismantling of the nuclear power plant, we have removed the spent fuel elements from the reactor core. That makes the subsequent dismantling easier and safer," explains Willicks. Removal of the fuel elements was completed on 13 June 2017, and since then the Brunsbüttel power plant has been free of nuclear fuel elements.
The fuel elements are now at an intermediate storage site in specially designed containers. The time until the permit is issued is being used for additional preparation and detailed planning of the dismantling. Systems that are no longer needed, such as the cooling system for the fuel elements, have been permanently decommissioned. Sometimes, old systems are replaced by new ones. For example, the oversized auxiliary oil-fired boiler, which was formerly necessary to start up the power plant and supplied heat for the plant as a sort of by-product, has been replaced by a gas-fired heating system with lower environmental impact. In the turbine hall, the first machines that will be needed to process the waste materials from dismantling have already been set up.
Dismantling in all areas
Even after the permit is issued, there will not be many external signs of dismantling in the first years. Markus Willicks: "Put very simply, we are dismantling all systems, tanks, valves, fittings, pumps, steel platforms – actually everything – in the nuclear and controlled areas. Everything will be taken apart, cleaned (decontaminated), and either cleared and released or disposed of as radioactive waste. The low- and medium-radioactive waste will be packed in containers, which will later be taken to the national final repository. However, this repository will not be operational in time, so we are building an interim storage facility on site here for low- and medium-radioactive waste materials, where they will be stored temporarily until they are transported to the final repository," explains Willicks.
Dismantling the reactor pressure vessel
The first large project after the permit has been issued will be the dismantling and packing of the internal parts of the reactor pressure vessel. Work on these components, which were in the immediate vicinity of the fuel elements during operation, will be carried out under water to protect the employees against radiation. Dismantling of the reactor building and the turbine hall will start around the same time.
For a smooth dismantling process, it is essential that all resulting waste materials and recyclable materials can be taken away without delay in order to make room in the power plant for further dismantling. Along with the radioactive waste, which form the smallest proportion of the total waste materials (less than three per cent), all materials such as metals or rubble have to be treated and released. They will either be recycled or disposed of.
"The topic of waste disposal has aroused a lot of interest amongst the public, and we have already invited many visitor groups – politicians, media and special interest groups – to visit the power plant so that we can show them the process and answer questions in person," says Willicks with regard to efforts to conduct an intensive public dialogue.
Several hundred people will be carrying out the dismantling in the power plant, all depending on the phase. Along with radiation protection, occupational health and safety is a major consideration in the planning and execution of the tasks. "It is a lot of work, and it poses major challenges for everyone involved. Even so, dismantling a nuclear power plant is a very interesting job where everyone can contribute with their own experience," says Willicks.