Demolition of the old chimney and construction of the new one

Status: Completed
Period: 2014-2017


During the operation period, the chimney was used to channel the discharge of gaseous effluents coming from the turbine, the reactor and the Radwaste, all operating in vacuum condition and, thus, requiring a controlled exit point.

The chimney, located near the reactor building, was a truncated cone structure made of reinforced concrete, 95 metres high and with a diameter ranging from 5 metres of the base and 2 metres at the top.

In March 2014, the chimney demolition operations were started. The first stage included preliminary works and verification tests on present systems for the decontamination of the internal surface of the structure, such as: system and machine testing on a 12-metres high chimney mock-up (prototype) in reinforced concrete; waterproofing of areas; the consolidation of support structures.

The internal parts of the chimney were subsequently decontaminated, through scarification. This operation was carried out through a robot, specifically designed by Sogin that progressively moves up and down on the chimney walls to remove the slightly contaminated concrete layers. 


Robot extra​ction

After the decontamination, between August and November 2017, the structure was demolished. The demolition technique used was the controlled crushing, appropriate to ensure the best safety level and to avoid possible damages to the structures located near the chimney, amongst which there is the reactor building.

The demolition activities produced 830 tonnes of material, among which tonnes of material, among which 800 tonnes of concrete and 30 tonnes of metal. The non-releasable material resulted from scarification, equal to 7 cubic metres, was collected in drums that are now stored in the interim storage facility of the plant. The structure, which was part of the skyline of the plant, was replaced with a new steel chimney, shorter than the previous one and entered into service in February 2018. The new chimney, located next to the previous one, allows the safe discharge of the aerial effluents resulted from safe maintenance and decommissioning operations.