Navy expands investigation of welding by Newport News shipyard

Newport News

All Navy vessels built or maintained by Northrop Grumman Newport News since 2000 will undergo a technical assessment for faulty welds on non-nuclear piping systems, the service said Wednesday.

Besides aircraft carriers and submarines, the review will extend to surface combatants that have had repair work on the internal piping systems.

The testing stems from recent discoveries of contaminated welds on some Virginia-class submarines assembled by the yard. Navy and shipyard officials found that a copper alloy weld filler had been mistakenly used on some steel piping joints, an error that can cause a joint to crack and leak.

In new details released Wednesday, the Navy identified the specific piping systems where the faulty welds have been found so far.

Two welds that failed during routine testing of the submarine New Hampshire - triggering the Navy's investigation - occurred on a hydraulic line in the torpedo room and in the emergency main ballast tank blow system, the Navy said in response to written questions from The Virginian-Pilot.

A leak in the torpedo room system could take one or more of the torpedo tubes out of action. A leak in the ballast blow system - activated when a sub needs to surface in an emergency - would not affect the vessel's ability to surface, the Navy said.

"Analysis shows in both of these systems, if a failure occurred, the leak could be isolated and normal operation of the ship would continue," said

Katie Roberts, a spokeswoman for Naval Sea Systems Command in Washington.

The testing of the New Hampshire, currently under construction, occurred in Groton, Conn., at General Dynamics Electric Boat, which is assembling the subs with Northrop Grumman in a teaming arrangement.

Besides the New Hampshire, at least one contaminated or suspect weld has been found on two Virginia-class subs now in service - the Virginia and the Texas. Another was found on the New Mexico, now under construction in Newport News.

All of those welds attach piping to valves through which high-pressure air is suppled to the emergency ballast system, the Navy said. Neither the hull nor nuclear components of the nuclear-powered submarines are involved.

At this point, the weld problem, under investigation since October, "has had a minimal impact on naval operations," Roberts said.

A shipyard spokeswoman said Wednesday that it probably won't know how many Navy vessels will undergo an assessment until early January.

On Monday, the yard said the testing would include four aircraft carriers and three Los Angeles-class attack submarines. Now, surface combatants, such as destroyers or cruisers, serviced by shipyard employees since 2000 will be added to the list.

The Navy expects to complete an assessment of near-term concerns by the end of this month. An analysis of potential long-term effects should be finished by spring, Roberts said.

The welding mistake was traced to a "process deficiency" at the shipyard, by which welders and pipe fitters were allowed to carry two types of weld filler metal, each for different kinds of piping systems. That practice has been eliminated, the yard said. Also, the shipyard says it has required all of its approximately 3,000 welders and welding foremen to undergo retraining.

Jon W. Glass, (757) 446-2318, jon.glass@pilotonline.com