Beyond Design Basis The Marine Version

Current Events Fukushima and North Anna are technical historical markers of unique circumstances of seemingly low probability events that can hold significant consequences with respect to nuclear power plants. The circumstances involved showed an inherent resiliency built into the structures of the buildings and components.

Current Events Recent at-sea accidents involving US Navy submarines are worth looking at in the same light as the nuclear power plants. The power plant and submarine are very similar. Both represent superior technology in systems, structures and components and perform very reliably for many years.

Emergency Blow

Incident One On 8 January 2005 at 02:43 GMT, San Francisco collided with an undersea mountain about 675 kilometers (364 nautical miles, 420 statute miles) southeast of Guam while operating at Hi speed and more than 200 feet (61 m) deep. The collision was so serious that the vessel was almost lost — accounts detail a desperate struggle for positive buoyancy to surface after the forward ballast tanks were ruptured.undersea mountainGuam

USS San Francisco-SSN 711

Aftermath 23 crewmen suffered injuries One fatality. Petty officer died of head injuries on January 9 th due to abrupt contact with ship’s internal structure. Crew performed well to save ship. Cause determined to be improper navigation and failure to consult ship’s instrumentation. Ship inspected. Foundations. Rx Plant, Engine Room, Hull circularity San Francisco repaired with a bow from a decommissioned ship (Honolulu). Completed in 2008.

Incident Two On 20 March 2009 Hartford collided with amphibious transport dock USS New Orleans (LPD-18) in the Strait of Hormuz, slightly injuring 15 sailors on board. amphibious transport dockUSS New Orleans (LPD-18)Strait of Hormuz New Orleans (new ship) suffered ruptured fuel oil tank. Lost 25,000 gallons of oil. Sub rolled 90 degrees port and starboard after collision. Both ships continued under own power. Sub crew responsible for collision.

USS New Orleans

USS Hartford-SSN 768

USS Hartford in Open Sea

In Thames River to Sub Base Groton

Consequences Hartford repaired by Electric Boat. Hull circularity determined to be satisfactory. New sail fabricated. Had to be redesigned as original plans not compatible with modern construction methods. Retirees called back to help. Final cost about $120 Million. Sub returned to service in February 2011.

Happy Ending Hartford recently completed a 6 month patrol and accomplished tasking not attempted in over 15 years according to the COB (chief of the boat). Ship performed as expected which considering what it is designed to do is rather impressive.

Summary Fukushima survived the earthquake and tsunami after almost 40 years of service. Earthquake was about 10 times greater than design basis. North Anna survived an earthquake stronger than it’s design basis and has returned to service. Both submarines survived to be repaired and return to service.

Summary-cont’d Platforms that push the envelope exact a cost both monetarily and on operators. Nuclear ships and power plants are hard on their people. No industry is more introspective save NASA. These incidents serve to prove that the design, material specifications, building techniques, operational protocols, and maintenance of these unique structures have been accomplished well. Our collective efforts are clearly worthy. These results allow evolution with confidence!