The dismantling of the light roof of the engine room has been completed at the ChNPP under the NSC arch
At the Chornobyl NPP, under the Arch of new safe confinement (NSC) the dismantling of a potentially fire-hazardous roof of the engine room has been completed. The necessity and scope of these works were defined in the safety document of the conceptual project of the NSC Launch Complex No. 1.
The roof of the engine room of the fourth power unit of ChNPP has two layers: a pre-accidental and installed protective metal layer after the accident. It was discovered that one of the largest fires under the arch may be due to ignition of the pre-accidental roof of the engine room. In order to avoid emergencies, a system for detecting and extinguishing fires will be installed there: thermal imaging devices, foam generators and other equipment that will ensure its operation.
In order for the system to work effectively in the event of a fire, it was necessary to remove the post-accident metal layer of the roof. This will open the foam mixture access to a potential source of ignition.
Taking into account the fact that the personnel had to work in complicated conditions of radiation contamination, it was decided to dismantle not all of the roof, but separate sections every 12 meters.
To date, the entire area of post-accidental roof, which was determined by the project, was dismantled. At present, the division of dismantled structures into fragments, decontamination and export them to a specially equipped storage area continue.