Case Study: Decommissioning of four reactors at Oskarshamn and Barsebäck NNPs

The Uniper portfolio approach

Successfully dismantling a nuclear reactor requires experience, know-how and the resources to carry out the task in a cost-effective and safe way. Successfull dismanting of four nuclear reactors –that requires something that no one has ever done before. After carefully evaluating several options, we decided on the Uniper portfolio approach. This approach combines all four power plant units into one program.

Dismantling of large components

In excess of 25,000 tons of equipment have been dismantled and removed in the project. Since it started in 2020, the dismantling of generators, turbines and condensers has been completed at all four nuclear reactors.

Unique learning curves and cost reduction opportunities

The Uniper portfolio approach including four units offers unique learning-curve and cost-reduction opportunities, especially in work packages such as RPV dismantling, turbine and generator dismantling, and condenser dismantling. After four years of decommissioning work, the program is within budget and on schedule.

Benefits of using the portfolio approach

Learning-curve effects between the work packages in the different units. Transfer of experience and lessons learned from one unit to the next.
Synergies in planning, work activities, preparations and tools, e.g. the possibility to “plan once, execute four times”.
Economies of scale through procurement of larger quantities, for example:
- One order for four similar work packages
- Common waste sorting/packaging stations for waste packages
Lean organization through application of portfolio management and implementation, with a joint project management office, work package managers, etc.

Dismantling the Reactor pressure vessel (RPV)

Using gas cutting and an innovative approach, the RVP is divided into large metal rings. Each ring is lifted into a custom-built robotic station, where it is cut into smaller pieces.

Dismantling the biological shield

During the dismantling of the biological shield, important improvements have been made to make the work safer and more efficient. The optimization efforts relate to both the execution of the work and waste management. In total, around 1,400 tons of concrete will be removed at each biological shield.

Dismantling the condenser

When dismantling the condenser, the aim was to minimize the amount of radioactive waste. Our solution was to waterblast the inside of the condenser before cutting it into pieces. The metal was directly free-released at site and then sent to metal recycling.

Dismantling the reheater

The 150-ton reheater was located between the high and low-pressure turbines during operation. Despite this, about 95% of the material was measured and classified free from radioactivity and recycled.