Friday, March 21, 2008; Posted: 08:11 PM
Critical piping systems on each of those vessels have been inspected and certified for short-term performance. Northrop Grumman must submit a long-term corrective action plan to the Navy on submarines by April 15, and another action plan for surface ships later this summer.
The long-term action plan is likely to include periodic inspections on internal piping joints welded in Newport News to ensure that those joints hold up over "many years, through the cycle of loading and corrosion," said Capt. Dave Johnson, the Navy's Team Submarine Program Manager.
Navy officials are working with yard inspectors and a technical review team to craft the corrective action plan, Johnson said.
In early December, Northrop acknowledged problems with a yard welding procedure that lead to a Navy investigation of all Newport News-built vessels. The problem was traced to Newport News welders and pipe fitters who used an incorrect weld-filler material to fuse pipes to steel joints in non-nuclear systems. Those errors could lead to cracking in the joints and, eventually, leaks.
Inspectors looked at about 200 welds on critical systems in each of the four completed Virginia-class submarines and found only one error -- a faulty weld on a 2-inch joint on the USS Virginia's emergency main ballast tank blowout system, Johnson said. No criticial welding errors were found in the North Carolina. Two critical errors were found on the yet-to-be delivered New Hampshire.
"Is that the entire population of welds? No," Johnson said. "But we looked at the ones where you really, no kidding, have got to be 100 percent sure" are built correctly.
He characterized the inspection process as "routine" and said from a cost standpoint, "It's not a big deal."
Even so, the problem was "big enough for us to keep ships tied up alongside piers for a few days," Johnson said.
Meanwhile, all ships have been cleared and Northrop Grumman has changed some of its process to ensure that any errors are caught well in advance, said Mike Petters, president of the company's Shipbuilding sector.
"Everybody is back at sea, and everything is OK at least for the short-term," he said. "Now, we're trying to prove to ourselves and to our customer that we can do everything correctly."
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