Tuesday, December 18, 2007

Russia's Not So Super Secret Special Submarine

The Sub Report has an article up on a new submarine produced in "secret" in Russia. I have worked with Russians since 1996 and trust me, they don't have any secrets that date back to the cold war, they were all sold long ago to the highest bidder. However, that didn't explain why when I read about this news today, something rang a bell.

The Sevmash plant in Severodvinsk, Arkhangelsk Oblast, has completed construction of the B-90 “Sarov”, a new diesel-fuelled submarine with a nuclear reactor as a supplementary power generator.

The B-90 “Sarov”, which is part of the project 20 120, left the shipyard on Friday, a press note from the Sevmash company reports.

The vessel is unique with its combination of diesel and reactor engine. The sub is likely to be applied by the Northern Fleet as spy vessel in northern waters.

The vessel has been designed by the Rubin engineering company in 1989. Construction was started at the Krasnoe Sormovo shipyard in Nizhnii Novgorod, and then later continued at the Sevmash plant.

It took us a few minutes to remember where we had heard about this submarine, and most likely, you have probably heard about this submarine and didn't know it also. Project 20120 was the submarine whose details were accidentally revealed on the internet earlier this year on the City of Sarov website.

According to the official press release, and other Russian news services, the submarine is a technology demonstrator. Designed in 1989, one has to wonder if this was a cold war project that was better left unfinished. Unless Russia has invented a light switch for turning a nuclear reactor on and off, it is hard to consider this type of hybrid powered submarine some sort of revolutionary design. But after doing a bit more research, it may be a revolutionary design though for AIP, Stratfor detailed back in September:

Sarov was once the secretive closed city Arzamas-16, also known as the Russian Los Alamos for its role in the Soviet nuclear weapons program. Though nuclear submarine construction is well-established at the Sevmash shipyards in Severodvinsk, Sarov could be a site for further research into the use of radioisotope thermoelectric generators (RTGs).

RTGs use the heat of radioactive decay from radioisotopes like plutonium-238 and strontium-90 to generate electricity. They are much simpler than full-fledged naval reactors and have been used to power remote lighthouses and weather stations as well as deep space probes unable to rely on solar energy.

However, there are technological hurdles that must be overcome. RTGs have been used predominantly in situations where wattage was not the limiting factor. Modern RTGs used on NASA probes produce hundreds of watts and are about the size and weight of a 120-pound person. But to use both German and Swedish systems as a benchmark, a magnitude of 200 to 300 kilowatts is necessary for AIP. Though much of this distance can be overcome by designing an RTG specifically for this purpose and then fitting multiple RTGs to the submarine, there is still a technological gap the Russians would have had to overcome.

The point is not how an RTG-based AIP would stack up against the German or Swedish methods; rather, the point is that an RTG is rather uniquely fitted to the Russian knowledge base -- and the Sarov locale.

Though not earth-shattering, a successful AIP uniquely suited to the Russian defense industry is a potentially significant development for the next generation of Russian patrol subs -- both for domestic coastal defense and export abroad.

The specifications of the Project 20120 "super secret submarine" are:

Length: 72.6m
Width: 9.9m
Draught: 7m
Displacement: 2300/3950 tons
Diving depth: 300m
Speed: 10/17 kts
Endurance: 45 days

According to the official press release, the submarine requires a crew of 52, which is actually one more person than the Akula class SSN, so we assume one more enlisted (25 officers, 27 enlisted). While the news report quoted above claims the submarine will be used as a "spy" submarine, we see the submarine being put to use as a training vessel and technology demonstrator.

While Stratfor is speculating, all of the data we are seeing does seem to fit the picture they painted back in September. If indeed Russia has come up with a hybrid RTG-based AIP system that is as effective as European AIP designs, then it would confirm what we have been hearing that Russia's design base for submarines is still very healthy and the innovation is still there. It will be interesting to see what details come out via the media over the next few days.

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