* U.S. nuclear submarine in collision in Strait of Hormuz
* Submarine hits second U.S. Navy vessel, 15 hurt
* No damage to sub’s atomic plant
(Adds details, background)
By Raissa Kasolowsky
DUBAI, March 20 (Reuters) - A nuclear-powered U.S. submarine and another U.S. vessel collided on Friday in the Strait of Hormuz bordering Iran, but there was no damage to the atomic propulsion unit, the U.S. Navy said.
Fifteen sailors were slightly injured in the collision between the submarine USS Hartford and an amphibious vessel, USS New Orleans, the Navy said in a statement.
It was the second collision involving a U.S. nuclear submarine in the Strait of Hormuz in just over two years.
"There is no damage to the nuclear propulsion plant of the Hartford," U.S. Fifth Fleet spokesman Lieutenant Nathan Christensen told Reuters.
The Strait of Hormuz, a narrow stretch of water separating Oman and Iran, connects the biggest Gulf oil producers, such as Saudi Arabia, with the Gulf of Oman and the Arabian Sea.
Around 40 percent of globally traded oil leaves the region through the Strait, which borders Iran.
The collision coincided with intense diplomatic activity between the United States and Iran, whose relations have been strained by Tehran’s nuclear programme that the West fears is to make an atomic bomb — an accusation Tehran denies.
U.S. President Barack Obama has made his warmest offer yet of a fresh start in relations with Iran, which cautiously welcomed the overture but said on Friday it was waiting for "practical steps", not talk.
Relations have been almost deep-frozen for decades, and remain blighted by differences over Iran’s nuclear programme, Iraq, Israel and other issues.
Asked how the latest collision in the strait occurred, Christensen said:
"It was a night-time event and the submarine was submerged at the time.
"There is no disruption to shipping traffic in the Strait. Both ships are operating under their own power and have passed through the strait," he said.
In January, 2007, the U.S. nuclear submarine USS Newport News and a Japanese tanker collided in the Strait of Hormuz.
No one was hurt in that incident and the submarine commander was removed from his post due to "a lack of confidence in his ability to command".
The 15 injured in the latest collision in the early hours of Friday were aboard the submarine Hartford, and the accident caused an oil spill.
"New Orleans suffered a ruptured fuel tank, which resulted in an oil spill of approximately 25,000 gallons of diesel fuel marine," the U.S. Navy statement read, adding the incident was being investigated.
"Both the submarine and the ship are currently on regularly scheduled deployments to the U.S. Navy Central Command area of responsibility conducting Maritime Security Operations," it added.
The collision pushed up oil prices, which subsequently hovered above a four-month high on Friday at $52 a barrel.
In July 2008, the International Energy Agency estimated that more than 15 million barrels per day (bpd) of crude passed through the narrow strait on tankers. (Editing by Charles Dick)