U.S. nuclear sub-docks closed due to ‘seismic’ issues – Reuters

Four dry docks in Washington state have been idle amid concerns over an earthquake study
The US Navy has announced the closure of four dry docks in the Seattle area due to security risks posed if a major earthquake hits the area. The service is already struggling to meet the maintenance needs of its nuclear-powered attack submarines.
Three nuclear-certified drydocks at the Puget Sound Naval Shipyard in Bremerton, Wash., and one location at the Trident Refit Facility in nearby Bangor, have suspended submarine docking for assessment and updates. level further, the Navy said in a statement.
Officials did not elaborate on what the recently completed seismic survey showed; nor did they offer an estimate of how long the affected dry docks will be out of service.
Seismic evaluation “identified potential issues associated with the low possibility of a large-scale earthquake occurring simultaneously with the availability of a submarine for maintenance”, said the Navy. “With this new information, the Navy is taking additional steps to further ensure the safety of the shipyard workforce, sailors, local public, environment and submarines.”
The Pacific Northwest lies near the Cascadia Subduction Zone, a fault line that stretches 700 miles along the coast from Vancouver Island to northern California. Scientists have warned that the flaw is capable of triggering a “megathrust” earthquake registering a magnitude greater than 9.0 on the Richter scale, as it did in 1700, and has a 37% chance of causing an earthquake with a magnitude of at least 7.1 over the next 50 years.
The Navy knowingly built the Puget Sound shipyard in an active seismic zone, but some of its drydocks were not equipped enough for a major earthquake. For example, one of the slots included in the suspension order would have been built on “unconsolidated earth and fill”, putting it at greater risk of liquefaction during a large earthquake.
Although the Navy has insisted that the dry dock shutdowns will not affect the nation “strategic deterrence capability” the move comes at a time when 36% of U.S. attack submarines are undergoing maintenance or are awaiting service. Even before the suspension, the Navy had only 18 drydocks to handle all of its submarines and aircraft carriers. Over the past decade, only 20 to 30 percent of submarine maintenance projects have been completed on time, the Navy said last year.
The Puget Sound shipyard is over 130 years old, and upgrading just one of the suspended dry docks will cost about $667 million.
You can share this story on social media:
RT