Repairs of the Yekaterinburg nuclear sub, damaged by fire while in dry dock near Murmansk, will take no less than a year, a spokesman for the Zvezdochka shipyard in Severodvinsk said.

The outer hull of the Yekaterinburg, a Delta-class nuclear submarine, caught fire on Thursday during repairs when when fuel and lubricants were set ablaze by welding in the system’s nose section. Fire safety violations during routine maintenance works are cited as the most likely cause.

The submarine’s hydro acoustic system was disabled by the fire and possibly will have to be replaced before it is brought back into service.

“According to our specialists, the repair terms will be known as soon as the damage is assessed and when it becomes clear whether a new hydro acoustic complex is needed for the sub,” Zvezdochka spokesman Yevgeny Gladyshev said. “According to our first assessments, repairs may take as long as one year.”

It is yet unclear at what facility the sub will be repaired.