MOSCOW, April 7. /TASS/. Rear Admiral Igor Zvarich, the head of the Russian Navy's technical department, has flown to Severodvinsk to investigates causes of the fire onboard the Oryol nuclear submarine at the Zvyozdochka shipyard, a spokesman for the Russian Defense Ministry told TASS on Tuesday.

Igor Konashenkov said that Zvarich has headed to Severodvinsk "following the orders of Admiral Viktor Chirkov, the Navy's commander-in-chief."

He said the submarine, which has been undergoing repairs since November 2013, had no nuclear fuel.

It was earlier reported that a nuclear submarine had caught fire at a repair center of the Zvyozdochka shipyard in Russia's Severodvinsk. Later, a defense industry sector source said the fire at the sub had been localized.

Spokesman for the Russian Defence Ministry Major General Igor Konashenkov told TASS that the ammunition load of the submarine had been removed, the vessel’s power unit was shut down when the fire broke out.