Russia Disposes of 195 Decommissioned Soviet-Era Nuclear Submarines*

Currently, 195 of the 201 decommissioned submarines have been recycled. The demolition of the rest submarines and 14 technical support vessels is due to be completed by 2020.

Russia’s Rosatom Corporation is nearing to complete the recycling of Soviet-made decommissioned nuclear-powered submarines and support vessels.

Currently, 195 of the 201 decommissioned submarines have been recycled. The demolition of all the decommissioned nuclear submarines and 14 technical support vessels is due to be completed by 2020.

"We have started the recycling of technical support vessels and depot ships. By 2020, we are expected to complete the dismantling and recycling of all 14 support ships decommissioned from the Northern and the Pacific Fleets as well as two Atomflot support ships," Rosatom CEO Sergei Kirienko said during the "70th anniversary of the Russian Atom" forum in Chelyabinsk.

"195 of the 201 submarines have been dismantled and recycled. Six submarines are left. Now we have no vessels standing in queue for dismantling. In 1999, when Rosatom was charged with the disposal there were 120 submarines waiting," Kirienko said.

In 2014, the recycling of the "Volodarsky" depot ship was completed. Now, the dismantling of the "Lepse" depot ship has begun. Within six months, it will have its nuclear fuel removed. Then it will be prepared for wet storage before the disposal.

Kirienko also pointed out that under the "Nuclear radioactive safety 2" program new equipment and technology were developed, including the recycling technology for the uranium-beryllium fuel from project 705 submarines which were equipped with liquid-metal reactors.

The need to recycle nuclear submarines and depot ships emerged after the fall of the Soviet Union. At that time, military spending was significantly reduced. More than 200 submarines built in the 1950-1980s, and a large number of support vessels, were decommissioned from the Russian navy.

* Notícia publicada a Sputnik News. Més enllà de que Rússia hagi anat recuperant-se progressivament, la qüestió de la desactivació, desmantellament i reciclatge dels submarins nuclears d'era soviètica, cal que es segueixi.

Silent running: How do you navalise a variable speed drive for a modern warship?*

The Royal Navy's latest large procurement project, the Type 26 anti-submarine frigate, is proceeding well with many of the prime contractors being announced. One of the most fundamental is its propulsion system that has been awarded to General Electric's Power Conversion's naval business.

There are many challenges in providing propulsion on modern marine vessels, not least is one that fundamentally comes under the ambit of being a warship. The Type 26's primary role is searching for submarines, as well as a secondary role as a general support and humanitarian vessel. It means any propulsion system has to offer speed and efficiency, as well as near total silence – though not all at the same time. 

The Type 26 is slightly larger than the Type 23 Frigate it is replacing, with a basic displacement of around 6500 tonnes. It is also slightly longer at 150m, and due to its varied multi-mission role the range of the Type 26 was one of the key drivers during its design, some 7000 nautical miles. 

For this reason the ship uses a fairly well known 'hybrid' configuration in the marine industry known as combined diesel electric or gas (CODLOG). The reality for the Type 26 is that it will use a single large gas turbine that will directly drive both the ship's shaft lines via a splitting gearbox, in combination with four diesel generators. These will produce electricity and in turn power General Electric motors to drive the ships propellers at lower speeds and for near silent operation. 

"When we are running in stealth mode the propellers do not run on batteries," said Paul English, marine business leader for GE Power Conversion. "The diesel generators keep running and produce the power to the propellers and the rest of the ship. So the noise of these engines is isolated by putting them on acoustic mounts and in an acoustic enclosure to reduce the airborne noise." 

The gas turbines and the diesel generators will both use the same single onboard fuel – the NATO designated Dieso. While still broadly considered a distillate light fuel, it is slightly heavier than the diesel most of us are used to at service station pumps. However, it also has a much higher flash point, an obvious advantage for a ship likely to see combat during its service life. 

For higher speeds, the ship uses the gas turbine. "In this mode the gas turbine drives through a splitting gearbox, and then into a second reduction gearbox, which then drives the shafts and propeller." 

However, a gas turbine whirring away might well be an efficient and effective way of producing power and shifting the Type 26 to its top speed in excess of 28knots (32mph / 52kph), but when it needs to remain quiet and locate enemy submarines, its diesel generators kick in to enable near silent running. One of the key technologies enabling this propulsion system is its use of Variable Speed Drive (VSD) technology. 

"When the ship is operating quietly the gas turbine and subsequent gearboxes shut down so to eliminate all the mechanical noise from those pieces of equipment," said English. "The propellers are then turned by the ultra-quiet GE propulsion motors, using electricity produced by up to four diesel generators. The motors receive their electricity from a combination of VSDs. A VSD is basically a frequency converter that controls the frequency it sends to the propulsion motor. We need to do this since the diesel generators run at a constant 'mains' frequency (60Hz), which is fine for the normal equipment on the ship - like the pumps, as their electric motors only need to work at one speed. But, to control the speed of the ship through the water we need to be able to vary the shaft speed, so we obviously need to be able to change the frequency we give to the propulsion motor. 

"There are all sorts of ways of doing that, the Type 23 that this is replacing does it by using direct DC voltage to give us variable speed control, but the modern way of doing it is to modify the fixed AC supply waveform to one of a different frequency for the motor, via an initial conversion to a direct current. This is done by a technique called Pulse Width Modulation (PWM). We're already well in to the design phase for the motors and converters, with the motors being designed at the moment and the VSD technology being based on commercial equipment." 

The VSDs are controlled by computer to create variable frequencies that enable the speed control of the propeller. 

"The greater the frequency out, the faster the motor will go," said English. "Conversely the lower the frequency the slower the motor will go. 

"It is based on our standard MV3000 range of marinised drives. We produce hundreds of these for use in commercial shipping and the core electronics are the same, but we have to navalise it." 

Given the nature of the Type 26's primary role as an anti-submarine vessel, the drives have to ensure that the electrical waveform produced has very little noise and distortion, as any distorted waves going in to the motor will cause vibration and radiate noise in to the water. 

This is achieved using a variety of technologies, including filtering techniques and the use of special PWM strategies to smooth the input to the motor ultimately turning the ships' propellers. 

"The idea is it has to be very quiet as it is an anti-submarine frigate," said English. "So we put in a huge effort to reduce radiated noise from the ship to enable it to operate very effectively in that environment. 

"And like much of the ship's components, generally, the VSDs need to be made more robust and shock hardened. If a ship suffers an explosion, for example, the VSDs need to be designed to survive. We do that by optimising their design using advanced dynamic computer modelling as well as simple techniques like putting it on specific mounts and surrounding it in a strong frame." 

Fundamental to a low noise signature is the design of the motor. The motors, currently under design and development, must be carefully engineered to ensure that they generate a minimum of harmonics and to ensure the maximum of attenuation in the noise conduction paths. This work requires a great deal of computer modelling and the application of many years of data gathered from a large number of different noise quiet motor designs. There are very few companies in the world that have this capability and no other company has supplied more noise quiet, shock proof motors to the surface fleets of western Navies than GE. 

Technology Transfer 

By integrating gas turbines with an enhanced electric propulsion system, the Type 26 will be more efficient and have reduced fuel consumption compared to its predecessor as it is able to configure its electric propulsion system for a wider range of operational demands and over a wider speed range. The integration engineering to deliver a package that works, rather than just a collection of equipment, is key to this and integration is an area where GE Power Conversion has strength in depth; not just in the Naval arena but also in the wide range of commercial electric propulsion packages it produces. 

And this sits well with General Electric's larger marine business. As the International Maritime Organization increasingly look to introduce guidelines around ship efficiency and in particular with CO2 legislation becoming an increasing possibility in many regions, the integration of both gas turbine and electric propulsion technology, in a hybrid arrangement is likely to become much more prevalent in the civil marine industry. 

Author
Justin Cunningham

* Notícia publicada a Eureka Magazine. Article que interessarà a totes aquelles persones familiaritzades amb la guerra anti-submarina (ASW). Sovint pensem més en els sistemes d'armes i sensors que no pas en la propulsió. Quan es tracta de caçar submarins, mantenir el sigil és cabdal ja que una tripulació mínimament ben entrenada procurarà determinar la posició de les unitats d'escorta abans d'iniciar qualsevol maniobra d'aproximació a un grup de superfície. Si el submarí no pot obtenir "marcacions" de sonar prou consistens, s'haurà d'arriscar a aproxinar-se a la superfície... De ben segur que les Type 26 donaran sorpreses.

U.S. Submarines: Run Silent, Run Deep... On Diesel Engines?*

"Underway on nuclear power", radioed the skipper of USS Nautilus in 1955, after taking history's first nuclear-powered attack submarine to sea for the first time. Nautilus's maiden cruise left an indelible imprint on the navy. Her success, cheered on by the likes of Admiral Hyman Rickover, the godfather of naval nuclear propulsion, helped encode the supremacy of atomic power in the submarine force's cultural DNA.

Things were never the same after that. America built its last diesel-electric sub, once the state of the art, not long after Nautilus took to the sea. Not since 1990 has the U.S. Navy operated conventionally powered boats. It's been longer than that since they were frontline fighting ships. For a quarter-century, then, it's been all nukes, all the time. No U.S. shipbuilder even constructs diesel boats nowadays.

That was then. Now may be the time to break up the nuclear monopoly. To wit, imagine permanently forward-deploying a squadron of diesel attack boats, or SSKs, to likely hotspots. Such a force would expand America's silent service, reversing the ongoing slide in numbers of hulls. It would do so at reasonable cost in this age of budgetary stress. A standing East Asia squadron would be close to the action. Likely based in Japan and Guam, it would amplify the U.S.-Japanese fleet's prowess vis-á-vis China's navy and merchant marine. It would empower Washington and Tokyo to deny China access to offshore waters without committing the whole fleet of U.S. nuclear-powered boats to the endeavor. And in the process it would open up new vistas for building and reinforcing alliances.

Greater numbers, middling cost, a heavier punch in battle. That's a major contribution from such humble craft. U.S. submariners' diesel-propelled past could be, and should be, part of their future.

There's nothing new or especially radical about conventional U.S. subs' prowling the Western Pacific deep. They did so to devastating effect during World War II. For instance, the Philippine Islands was home to the largest concentration of U.S. submarines in the Pacific on the eve of hostilities. U.S. commanders squandered a golden opportunity to run wild against transports carrying Japanese troops to invade the Philippines. But their missed opportunity doesn't detract from subs' potential to confound opponents amid Asia's intricate nautical terrain. It's an exception that proves the rule.

And indeed, American submarines vindicated their potential in ensuing years. U.S. Pacific Fleet boats were among the first vessels to return to Asia following the Japanese raid on Pearl Harbor. Ordered to sea while the battle line was still ablaze at Ford Island, they helped dismember an island empire. Empires like Japan's depend on ships to ferry all manner of warmaking materiel—raw materials, foodstuffs, finished goods—hither and yon. Take away seaborne movement and you cut the lineaments binding the imperial enterprise together.

The submarine campaign grew more and more effective as the U.S. offensives undulated across the Central and South Pacific. U.S. Navy, Marine and Army amphibious forces wrested outer islands from Japan, letting the navy position, maintenance and logistics outposts closer to the foe. Submarine tenders—floating repair and supply depots for all intents and purposes—staged support operations westward of Hawaii. As the transpacific campaigns progressed, boats wasted less time transiting to and from assigned hunting grounds. They spent more time strewing the seafloor with enemy merchantmen and men-of-war.

Forward bases, then, offset the tyranny of distance—allowing the submarine force to mount a stifling presence in Asian waters. Wartime prime minister General Hideki Tōjō catalogued submarine warfare among three critical determinants of Japan's defeat—high praise from someone in a position to know.

And afterward? Ravaged by undersea combat during World War II, Japan built an impressive submarine force of its own to help prosecute the Cold War. Japan Maritime Self-Defense Force (JMSDF) diesel boats turned geography to advantage, lurking in and around the straits that pierce Asia's offshore island chains. Crews monitored and encumbered east-west movement between the China seas and the Western Pacific. Soviet skippers often balked at attempting the passage. The JMSDF, in short, forged itself into a lethal weapon for a cold war beneath the waves.

*Article complet fent click aquí. Tot i que el debat de recuperar els submarins dièsel/elèctrics no és nou, el professor James R. Holmes, torna a abordar el tema. Aquest tema, que ha estat gairebé tabú per l'obsessió quasi religiosa per la "all nuclear fleet", es suma a una altra " heretgia" com és l'aquisició d'un tipus de submarí dissenyat a l'estranger: AL JAPÓ! Esperem que facin cas a aquestes tesis, doncs l'equilibri de forces al Pacífic en depèn directament.

The Full Electric Warship Can Utilize STEALTH AC Propulsion*

The Norwegian drive specialist STADT has introduced the STEALTH AC electric propulsion technology for naval ships in any category. The technology has been on the civil marine market for several years, and has proven its low noise characteristic there. STADT provides the fully integrated scope of electric propulsion, from main switchboards via the STEALTH AC drives and the electric propulsion motors.

The system has a unique set of valuable characteristics not seen from any other electric propulsion systems so far, such as negligible losses in the drive itself, compact design without big transformers, and use of very reliable technology all the way throughout the system.

No electromagnetic interference EMI - the STEALTH feature

STADT offers a real sine wave technology that is very different from the more known Pulse Width Modulation (PWM) type of AC motor drives. The Sine-wave motor control does not generate any Electromagnetic interference, the noise is fully eliminated. Thus complex screening of power cables for the propulsion drives are not needed any more.

An other advantage is the possibility for medium voltage grid, up to 15 kV system voltage for this new system, giving minimal electric field from the ships systems.

No harmonic voltage disturbances THD

The STEALTH drives also pulls linear power from the generators, so no disturbances are generated. The ship grid will operated with a pure un-distorted voltage within all of its main switchboards. This eliminates any overheating of power components and eliminates malfunctions of any kind.

No big transformer needed

Up till now electric propulsion systems has used very big an heavy propulsion transformers, for the purpose of cancelling harmonic distortion from the PWM drives. The STADT STEALTH AC drives do not need such filtering, thus the transformers are obsolete. This contributes to major weight savings, as well as space and loss reduction. And one less item that might fail.

NO-LOSS AC drive, patented

In practical terms, the STADT STEALTH AC drive does not generate any excessive heat during operation, except from electric losses in alternator and electric propulsion motors. This leads to additional system benefits such as:

• Less fuel consumption, up to 8 % improvement compared to other type of electric systems
• Longer endurance for the ship
• Less emission of COx, NOx, etc
• Less wild heat dissipation, reduced need for air condition systems etc
• Increased reliability

This also leads to elimination of intricate water cooling systems within the AC drive, again leading to improved reliability.

Compact design saves space

The new drives saves space due to the eliminated need for big transformers, and due to a major reduction of number of components in the inverter topology. Improvements of more than 50 % in weight and volume is possible.

Rugged technology, well proven and approved

Throughout the years of development, STADT has focused very much on how to improve reliability in electric drives for propulsion. Vulnerable components such as capacitors has got a modest role to play in the new STEALTH drives. Insulation strategy is also improved dramatically, and robust thyristors plays an important role in parallel with IGBT switching and bypassing element operating in sequence.

The drive topology takes advantage of the best features in each components type, and utilizes them in the most effective way. Giving a solution with the desired new features mentioned.

The STEALTH drives also operates in conjunction with the CPP propeller systems to perform optimal manouverability and optimal energy efficiency for the vessel.

Redundancy is part of the solution

To avoid the situation where a tiny component failure might stop the ship propulsion, STADT has for this drive system implemented a redundant concept from generators, via MSB, drives and electric propulsion motors that takes redundancy in to account in each level of the system.

Electric Ship Propulsion motors, generators and switchboards

The STADT drive systems can be supplied with custom built AC propulsion motors in different technologies, such as navy approved with water cooling, as well as new designs based on superconducting elements to reach the most compact design with highest efficiency.

Comprehensive product range

The STEALTH AC drives are available from 100 kW and up to 100 MW in different configurations and a full range of voltage classes - 230 V to 15 kV.

* Nota publicada a Naval Technology. Tot i que poc coneguda, la indústria de defensa noruega ha fet grans aportacions. No tenim cap dubte que aquesta ho tornarà a ser. Més encara si ha d'anar en els destructors de classe Zumwalt, dels que es diu que tindran una signatura acústica comparable a la d'un SSN classe Los Angeles