Sogin: demolition of the Garigliano nuclear power plant chimney is over

14 November 2017

Today, at the Garigliano (Caserta) Nuclear Power Plant, Sogin has completed the dismantling of the chimney, a truncated cone-shaped, 95 metre high structure made of reinforced concrete, with a diameter ranging between 5 metres at the bottom and 2 metres at the top.

The structure, which characterized the skyline of the plant, will be now replaced by a new, almost three times lower, steel chimney which will be needed for the forthcoming decommissioning activities. A controlled crushing demolition technique has been adopted. Among the various examined techniques, controlled crushing showed the highest safety level and the ability to avoid possible consequences to the neighbouring structures, including the reactor building.

Starting from the top of the chimney, the structure has been gradually dismantled, with the resulting materials falling inside the cone itself. Sogin began the activities for the chimney demolition in March 2014. At an early stage, preparatory works have been carried out such as: systems and machinery tests using a 12 metre high chimney mock-up, dismantling yard waterproofing and structures reinforcement. Subsequently, the inner of the chimney has been decontaminated by scarifyication. For these operations a specifically designed, Italian technology robot has been used. The robot moved inside the chimney from top to bottom and removed thin layers of lightly contaminated concrete for a maximum thickness of 1 centimetre.

The decontamination allowed Sogin to demolish the chimney as a conventional structure. The total value of the performed activities, including the new chimney building, is worth about EUR 10 million. The demolition works produced about 830 tonnes of waste, 800 tonnes of which was made of concrete and 30 tonnes of metal.

The contaminated material resulting from the scarification amounts to 7 cubic metres. It has been treated and stored in the plant interim repository. Within the Garigliano Nuclear Power Plant decommissioning plan, Sogin has completed today a relevant project, characterised by all-italian design solutions and technologies, confirming the excellence of its know-how in the nuclear decommissioning industry.