It appears that many of my fellow members consider SSN a panacea for all naval problems. Let us briefly discuss main points.
Firstly the cost: Royal Navy’s new Vanguard class submarine costs a whopping £1.5-billion in 1993 value. This translates into more $3-billion each. Type 214 on the other cost $330-milllion per unit in 2008 dollars. This means one could buy about 6 type 214 for the price of a single SSN. Cost for decommissioning SSN could be as much again; I will come to that later.
Speed: Vanguard class can speed up to about 30- knots; However at that speed noise from the sub’s propellers is so much that it becomes difficult to hear the SONAR. Thus normal submerged speed is about 20 knots. Modern SSK such as type 214 can achieve 20 knots for fast get away; even higher speeds are possible for short sprints of up to 30 minutes.
Range: Submarine is the ultimate stealth weapon. Therefore range is far more important as it gives the ability to ambush the enemy deep in the blue water. While SSK can’t compete with SSN; range of 12,000 nm on surface and in excess of 1,000 nm submerged, is more than sufficient for most countries defence needs.
In addition to the fuel, one of the key factors that determine the range is the provision of food & water for the crew. While water can be obtained thru distillation of sea water (SSN), longer the range, more space is needed for the provisions. Very long stay at sea also gives rise to psychological problems. SSN has limitless power supply, however due to shortage of space for food, most SSN stay at the sea for about 6 months. Modern SSK can be at sea for about 3 months only.
Stealth: SSK is also considerably smaller (about 2,000 tons for SSK versus 15,000 tons for SSN) therefore better at hiding under the sea. State of the art SSK is also stealthier than the SSN. There are two reasons for it.
In SSK one can switch off the engine and remain in absolute silence. SSN however cannot shut down nuclear reactors and some noise from pumps will always remain. Another stealth weakness of the SSSN is the need to cool the reactor even when the submarine is not moving.
About 70% of the reactor output heat is dissipated into the sea water; this leaves a "thermal wake" that is, a plume of warm water of lower density which ascends to the sea surface and creates a "thermal scar" that is observable by thermal imaging systems such as Forward Looking Infra-red cameras (FLIR). In this aspect SSN is definitely inferior to the state of art SSK.
For me, the major drawback of SSN only surfaces upon decommissioning. Sooner or later all equipment has to be retired from service. How to dispose-off the waste from the nuclear reactors that power the SSN? It is estimated that nuclear waste from the defence sources could be about 1/6 of all the nuclear waste in Britain.
Decommissioning of the UK Trident submarines left the long term problem of what to do with the reactor itself and the surrounding hull, unresolved. It is possible to substantially reduce the level of radiation in components of the reactor. This can be done by chemical processes. However, the chemical process in turn also produces nuclear waste. At the end there would still be a large volume of low level waste and a smaller volume of intermediate waste which will remain radioactive for generations.
UK ministry of Defence (MoD) would like to fill the submarines with concrete and sink them in the Atlantic but future monitoring would be difficult, recovery virtually impossible and there would be serious international objections. Shallow burial on land is another option, a number of American submarines have been dumped this way. Nevertheless, there is no easy answer to the question of what to do with a decommissioned SSN. When the Royal Navy first introduced nuclear powered submarines they did not even consider this issue. Almost 30 years later, MOD have still not been able to find a solution.
Russians have their nuclear waste disposal site in at Bolshoi Kamen, opposite to the city of Vladivostok on the Siberian East coast. Main activity of Sveda factory at Bolshoi Kamen is cleansing reactors of nuclear submarines after the same have been de-activated. However it is very dangerous work and the gravestones show that most people die young; in their 30’s & forties.
Apart from other arguments posted earlier; in my opinion proliferation of SSN in the navies of less ecologically aware countries is bad for the environment. Perhaps now one can see why I am strongly opposed to SSN’s.
