Small blast on Russian sub, no radiation leak-Ifax

MOSCOW, July 27 (Reuters) A small explosion occurred on a Russian navy submarine believed to have a nuclear reactor on board but there was no leak of radiation, Russia's Interfax news agency reported today.

It said the explosion happened yesterday aboard a Russian Northern Fleet submarine as it underwent repairs at a dockyard in the port of Severodvinsk, on the White Sea. Russia's navy could not immediately be reached for comment.

''The background radioactive level at 10:00 a.m. local time 1130hrs on July 27 was ... in line with the natural level,'' Interfax quoted a spokesman for the local environmental monitoring agency as saying.

The atomic safety authority in nearby Norway said it was checking for any increase in radioactivity in its region but had no further comment.

Interfax quoted an unnamed source in Severodvinsk's administration as saying there had been explosion which caused no casualties but which damaged a 25 square metre section of the submarine's hull.

It also quoted an official at the Zvyozdochka shipyard, where the incident happened, as saying it was not a blast but a ''bang'' caused by the sudden release of air under pressure.

Interfax quoted unofficial sources as saying the submarine involved is atomic-powered, but the officials it cited refused to confirm this.

Russia's has a history of incidents -- some of them fatal -- in its submarine fleet. Modernisation is under way, but many of the vessels have been in operation beyond their normal service life.

In the worst incident of the past few years, the Kursk submarine sank to the bottom of the Barents Sea on August 12, 2000, after two explosions on board. All 118 crew members died.

In September last year, a fire on board the submarine St Daniel of Moscow, moored near the Finnish border, killed two crew members.

REUTERS GT RN1711