MOSCOW — The Soviet Union said Monday that, despite a pipe that burst in the reactor of one of its nuclear-powered submarines and an apparent fire that followed, there has been no radiation leakage from the vessel in the Norwegian Sea and no casualties.
Gen. Dmitri T. Yazov, the Soviet defense minister, told the government newspaper Izvestia that the pressure seals around the submarine's main power plant had also been broken when the high-pressure pipe burst during a dive.
But Yazov said that the vessel's captain had managed to bring the damaged submarine to the surface quickly and shut down the nuclear power plant, which has twin reactors, without any radiation leakage.
The submarine was proceeding slowly under auxiliary power toward its base at Severomorsk, north of Murmansk, in the Soviet Arctic, Yazov added, and a Soviet warship was en route to take it in tow. Two other Soviet ships are providing fresh water to cool the reactors.
Fleet Adm. Vladimir N. Chernavin, commander in chief of the Soviet navy, said later in a television interview that the submarine had been carrying nuclear as well as conventional weapons but that "all are safe." Radiation levels inside and around the submarine are normal, he said.
"There was no worsening of the situation during the day," Chernavin said. "There is no need to take emergency measures beyond what we have done. There is no special threat to either the crew or the submarine at this time."
The submarine was identified by Norwegian defense officials as an Echo II class sub, about 380 feet long, probably built in the early to mid-1960s and carrying about 90 crew members. Most of the 29 Echo II boats in service carry both nuclear-tipped cruise missiles and torpedoes with nuclear warheads, according to Jane's Fighting Ships, the authoritative British naval review. However, many of the boats are now used mostly for training.
The fire, which was first reported by Norwegian officials in the early morning, had either been brought under control quickly, Soviet officials said, or perhaps was simply the smoke from the sub's diesel auxiliary engines.
The accident, which occurred about 60 miles off the northern Norwegian coast and 210 miles south of Bear Island far inside the Arctic Circle, was in the same region as an April 7 accident in which another Soviet nuclear submarine caught fire and sank, killing 42 of its crew members. That accident is still under investigation.
Together, the two incidents raise serious questions about the safety of the Soviet Union's large fleet of nearly 400 nuclear-powered submarines, many of which are more than 20 years old, and about the operating procedures followed by their crews, which have been criticized recently as poorly trained.
A Soviet naval officer, in a letter to the popular magazine Smena, complained that "the nuclear installations on our submarines are operated by people who are insufficiently trained and by some not trained at all."
"But we still go on sailing," Capt. V. Ovchinnikov said, writing from Murmansk, headquarters of the Soviet Northern Fleet. "The crew operating (the nuclear power units) know and can cope with only 30% to 50% of what they should know and be capable of handling."
And a U.S. naval analyst, Jan Beemer, wrote in a recent study of the Soviet submarine fleet that, "short of mechanical parts and subject to frequent mechanical breakdowns, many of the older submarines, perhaps as many as 40% of the fleet, have become more dangerous to their own crews than to their Western opponents."
The sense of maritime crisis was increased by another accident, that of a Soviet passenger liner which smashed into a belt of drifting ice near Norway's Spitsbergen Island last week with about 950 people aboard. Although no one was hurt, the incident raised further questions about Soviet seamanship.
Norwegians, who reported the incident hours before the Soviet Defense Ministry would even confirm it, complained that Moscow was failing in its duty to advise its neighbors of potential dangers.
A Norwegian Foreign Ministry official said, "We do not find it satisfactory that for the third time . . . we have had to ask Soviet authorities for information on accidents that have happened this close to Norway." But Norwegian officials said that, so far, no radiation leaks had been detected.
Norwegian defense aircraft, F-16 fighters and Sea King helicopters, which approached to inspect the damage and offer assistance, were waved off by the submarine's crew, most of whom had been mustered on deck in life jackets as the vessel sailed slowly eastward, billowing black smoke.
Later, the Soviet sea rescue center in Murmansk telexed Norway's northern defense command that the fire was under control, that the crew was safe and that there was no danger of a radiation leak, Norwegian officials said.