The creeping smoldering after the Russian drone attack on the Chernobyl nuclear power plant is due to the waterproof film used in the space between the arch linings.
This opinion was expressed in a comment to Ukrinform by Oleksandr Kupnyi, a radiation safety expert who worked at the Chornobyl NPP after the accident in 1986.
“There is mineral wool with different properties (in particular, basalt), but it is not combustible. An insulating membrane was used between its layers, which does not allow moisture to pass through, and glued to the mineral wool. And this thin black film and glue have the ability to burn and smolder,” the expert explained.
According to him, the multilayer filling between the inner and outer cladding of the arch was provided for thermal insulation and sealing. Prior to the installation of the structure, the insulating sandwich (the outer skin of the arch space) was tested by heating to high temperatures that could be caused by sunlight or lightning. The materials passed the tests successfully.
“Probably because the discharge heated the metal, but the “filling” did not melt. And the explosion that tore everything apart caused a flame, and this membrane caught fire. And then it started to smolder. Experts confirmed to me that the film can smolder between the insulating layers,” Kupnyi said.
The smoldering is spreading to different sides of the arch and to the western and eastern walls, because it is very difficult to get to the film and prevent the process.
“I suspect that nothing can be done until the entire membrane burns out. The cladding is ruined,” Kupnyi said.
According to the expert, extinguishing the fire creates additional threats to the functioning of the arch. “Probably, the only way to extinguish the fires is to cut out windows in the lining and fill them with water. But now everything under the outer cladding is saturated with moisture, it is frozen in the cold, it is not known how the frozen layers behave inside, but it is definitely a heavy load for the arch,” he explained.
According to Kupnyi, if the designers had divided the interior space into sections and made partitions inside the cladding, new centers of decay would not have arisen.
“As it is, the fate of the arch is sad: the cladding needs to be replaced completely, and it will cost more than the installation cost. And the 100-year warranty goes to hell,” he said.
As reported, the Chernobyl nuclear power plant continues to extinguish the smoldering centers that arose after the Russian drone attack on February 14. As reported by the State Emergency Service, rescuers are working to partially open the structure of the Shelter and eliminate smoldering areas on the arch. Monitoring of the structure with the help of thermal imagers and UAVs continues around the clock.
Source: Expert explains why arch at Chornobyl NPP is still smoldering
