Nuclear Reactors 457 - Crack In Weld Forces Britain To Dock Half Of Their Nuclear Hunter-Killer Submarines
I have often blogged about problems at nuclear power reactors. I have seldom blogged about problems with the nuclear engines that power submarines and ships. The nuclear engines are very well built and usually function reliably and safely. However, occasionally even these nuclear reactors have problems.
The British navy currently has seven nuclear hunter-killer submarines. There are four of the older Trafalgar class and three of the newer Astute class. There are four more Astute class hunter-killer submarines under construction. These classes of submarines are nuclear powered but they do not carry nuclear missiles. There are four Vanguard class nuclear submarines that carry British nuclear missiles. The hunter-killer class of submarines is intended to defend the British Isles from incursions by enemy submarine and to protect the Vanguard missile submarine.
There are only four Astute class submarines, two of which are being tested and the third is in dock to be repaired about a collision. Due to delays in getting the Astute class submarines constructed and deployed, the life span of the Trafalgar class submarines was extended by ten years.
Recently, the Trenchant, a Trafalgar class submarine, was found to have a crack in one of the pipes around the nuclear reactor. The crack is a fracture on a weld that connects a coolant pipe to the reactor. The fracture is about four inches long. It is classified as a "critical" fault but if it gets any bigger, it would be classified as a "catastrophic" fault. The weld is inside a water tank and is extremely difficult for technicians to access. The tank containing the weld has become progressively more radioactive as time has passed. The fracture may be impossible to repair which would force the navy to retire the submarine.
The fracture was classified as a "generic fault" meaning that other submarines in the Trafalgar class are also at risk for developing the same problem. The three other Trafalgar submarines are the same age as the Trenchant and it is possible that they will also have the same fracture. As a result, all four of the Trafalgar class submarines have been docked. They will remain in dock until they are thoroughly checked for the generic fault cracks in welds.
The hunter-killer submarines are intended to be able to maneuver quickly during combat. If there are flaws that are vulnerable to rapid changes in temperature and pressure such as cracks in pipe welds in a particular submarine, then that submarine would be a lame duck, afraid to move the way it is supposed to in a battle.
It is quite possible that all four of the Trafalgar class submarines will have to be withdrawn from service because they cannot be repaired. The nuclear reactors that power the submarines are designed to never need service during their operational life span. If they break, they cannot be repaired.
With four Trafalgar submarines docked for inspection, two Astute submarines undergoing sea trials and the third Astute submarine being repaired, Britain's entire hunter-killer fleet is unavailable for deployment. may have to ask the U.S. for help to maintain their submarine defense capability.
HMS Trenchant:
