The AT-6 unit sustained damage, caught fire and was shut down as an emergency measure, the sources said. Inter-shop communications — pipelines and pipe racks — were also damaged.
Three other primary processing units at the plant — AVT-1, AVT-3 and AVT-4 — remain operational. They may be used while AT-6 undergoes repair, according to the sources.
The Ryazan refinery has a nominal capacity of 17 million tonnes of crude oil a year. It can produce about 3.4 million tonnes of gasoline and 3.8 million tonnes of diesel fuel annually.
Reuters noted that AT-6 had already been damaged and shut down as an emergency measure after a drone raid on September 6.