Table of Contents

• Decommissioning of nuclear submarines
• 6.1 Laid up nuclear submarines
• 6.2 Safe storage of nuclear submarines
• 6.3 Dismantling of submarines
  • 6.3.1 Economic aspects
• 6.4 Parties to the work of dismantling submarines
• 6.5 Stages in decommissioning
  • 6.5.1 Preparation of the reactor compartments
  • 6.5.2 Dismantling submarines with damaged reactors
  • 6.5.3 Tansportation of reactor compartments
  • 6.5.4 Plans for long term storage of reactor compartments.
• 6.6 Radio ecological problems of dismantling
• Endnotes

Decommissioning of nuclear submarines

At this time, just over 130 nuclear powered submarines have been taken out of service and are laid up. Eighty-eight of them belong to the Northern Fleet; fifty-two still carry nuclear fuel in the reactors.[459] Fifteen reactor compartments have been removed from the hulls and have been prepared for storage. In all probability, around 150 nuclear submarines will be taken out of service with the Russian Navy by the year 2003.[460] Inactive Northern Fleet submarines are laid up at Gremikha, Severodvinsk, Vidyaevo (Olenya Bay, Sayda Bay and the Nerpa yards), Polyarny (Shkval), Sevmorput, Gadzhievo (Ara and Ura Bays) and Zapadnaya Litsa.[461] The dismantling of first and second generation submarines has commenced, whilst the dismantling of third generation vessels is still in the planning stage.[462]

Photo, 39 kb.
This Hotel class nuclear submarine is moored at the Sevmorput shipyard in Murmansk. Work on decommissioning the vessel had begun, but the spent fuel assemblies had not yet been removed from the reactor at the time that this photograph was taken. Above the reactor compartment may be seen a metallic coloured hut containing the equipment that is used for removing fuel assemblies from the reactor compartment. There are signs all around the quay where the submarine is moored warning of radiation danger, an indication that radiation from the reactor compartment can be measured outside the hull of the submarine.

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The reactor compartment from the Alfa class nuclear submarine K-47 has been in Severodvinsk since the 1970s. The fuel elements have been left inside the reactor because the metal coolant has solidified. There are plans to set the reactor afloat and tow it north to Gremikha on the Kola Peninsula for storage.

Photo.
These six nuclear submarines (five Yankee class and one Charlie class) are laid up at a pier at the naval base Belomorskaya in Severodvinsk awaiting decommissioning. Many of the submarines that are presently laid up are in very poor technical condition. Compressors for pressurised air are mounted in all six of the vessels pictured here. Pressurised air is pumped into the hull to prevent the submarines from sinking at the quay. There are clear signs of air bubbles in the water around the Yankee class submarine moored closest to the pier on the left side, a strong indication that the vessel's hull is not airtight. On the other side of the channel, to the far right of the photograph, the apartment blocks of Severodvinsk may be seen, a town with 210 000 inhabitants.
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6.1 Laid up nuclear submarines

Since the middle of the 1980s, nuclear powered submarines have been taken out of service and prepared for decommissioning.[463] The first generation nuclear submarines that were taken out of service early in the 1980s and laid up is now being prepared for dismantling. Until now Russia has not decommissioned a single submarine where the problems of handling and storage of reactor compartments have been solved in a satisfactory manner. The decommissioning of nuclear submarines has become a Russian national problem. There is a great shortage of qualified technical facilities coupled with a lack of sufficient funding to carry out the work. As increasing numbers of submarines are retired from active service, the lack of suitable storage for spent nuclear fuel and other nuclear waste will present a significant problem. Storage facilities are already filled to capacity.

Russian nuclear submarines are decommissioned for three reasons. Firstly, some of the vessels are more than 25 years old and past their effective operational life. Some of them have undergone serious accidents and are beyond repair. Secondly, the greatly reduced Russian defence budget precludes maintenance and upgrading of the large cold war force of nuclear submarines established by the Soviet Union. Thirdly, international disarmament treaties for the reduction of naval nuclear strategic warheads require a reduction in the number of submarines.[464]

Until the middle of the 1980s, older nuclear submarines were kept in service as long as possible. Most of these vessels were very run down and some of them spent up to ten years in ship repair yards. Large sums were spent on the maintenance of this large but ageing fleet. The only submarines that were taken out of service were those whose fuel assemblies had been so badly damaged that refuelling was impossible.[465] These vessels were either laid up or dumped in the Kara sea.

Until 1986, there were no formal plans for the decommissioning of obsolete nuclear submarines.[466] In 1986, the Central Committee of the Communist party and the Supreme Soviet ratified Decree No. 095-296 which laid down formal procedures for decommissioning and dismantling inactive nuclear submarines. The decree contained the following main points:

• Weapons and other important equipment to be removed. Vessels to be laid up with reduced crew in suitable locations at Navy yards.
• Fuel elements to be removed from the reactor.
• Decommissioning of vessel by cutting out the reactor compartment. Non-contaminated metal to be reused.
• Sealing and transporting the reactor compartments to suitable locations for long term storage. Storage to be undertaken where radiation safety is maintained and can be verified.

In connection with this, a special decree regarding safety routines for laid up nuclear submarines was ratified in early 1988.[467] It was not until 1991, under the precepts of Resolution No. 714/13/0105, that the Russian Navy adjusted its guidelines for delivering inactive submarines for dismantling.[468]

The first resolution regarding the order in which the submarines were to be delivered for dismantling came in July 1992 when the Russian government ratified Decree no. 514. According to this, a number of submarines scheduled for dismantling and metal recycling were to be transferred from Navy jurisdiction to shipyards subject to the Ministry of Industry. In this way, commercial enterprises gained access to decommissioning work. Specifically, three Project 705 - Alfa class nuclear submarines with liquid metal cooled reactors (factory nos. 905, 910 and 106), four Project 667 A - Yankee class submarines (factory nos. 451, 462, 470 and 421), one Project 670 - Charlie class submarine (factory no. 903), and one Project 671 - Victor class (factory no. 615) vessel were listed.[469]

The shipyards received the proceeds from the sale of scrap metal as payment for their work in decommissioning the submarines.

The Russian Navy, represented by the Supreme Commander of the Northern Fleet, Admiral Oleg Yerofeev, has expressed great displeasure over this decree. He feels that the Navy should benefit from the sale of scrap metal since the submarines are the property of the Russian Navy.[470]

In August 1993, the Russian government ratified Decree no. 644-47 concerning the completion of dismantling operations on nuclear submarines. The decree particularly addresses plans for upgrading the Zvezdochka naval yard in Severodvinsk and the Nerpa Shipyard on the Kola Peninsula. The upgrading concerns largely the construction of new dry docks and equipment for removal, transport and storage of spent nuclear fuel. It also encourages comprehensive research into the responsible decommissioning of nuclear submarines.[471] On May 1, 1994, Decree no. 548 outlining guidelines for the "federal programme for industrial decommissioning of weapons and equipment" was ratified.

The problems associated with the decommissioning of nuclear submarines were raised in the Duma on June 14, 1994, at the Commission for Emergency Action on March 14, 1995 and at two international conferences held in Severodvinsk on March 23, 1994, and in Moscow on June 19-20, 1995.

Despite the various decrees and discussion on the decommissioning of nuclear submarines, the actual work is far behind schedule. So far, no submarine has been decommissioned in a responsible manner in compliance with the regulations. Some submarines have been completely dismantled, but their reactor compartments have either been dumped in the Kara Sea or are still stored floating on the sea. According to naval yard authorities, safe decommissioning of nuclear submarines will not be possible for another five to seven years.[472] The Russian Ministry of Defence claims that the present economic situation rules out a sustainable rate of decommissioning before 2005-2010.[473] This is because of the time that is required to develop the necessary infrastructure. Many essential facilities are lacking, including proper equipment for defuelling the reactors, facilities for dismantling the vessels and above all, facilities for the treatment and storage of radioactive waste and reactor compartments.[474]

A new decommissioning dock for the Northern Fleet is under construction in Kherson, Ukraine, but delivery has been postponed by non-payment of the 8 million USD bill.[475] The safety of the mooring areas for decommissioned submarines today is considered unsatisfactory. The Northern Fleet Supreme Commander, Admiral Oleg Yerofeev, has stated that the level of safety at these sites is steadily deteriorating, and that there is a real danger of radioactivity being released from laid up submarines because they can sink. He considers the lack of suitable storage facilities for the reactor compartments to be the greatest problem.[476]

Of the 88 nuclear submarines that have been taken out of service, the location is known for 70. These are shown in the table below.[477]

Table 10: Summary of locations of laid up nuclear submarines, including number of defuelled vessels.[479]The summary states the number of submarines with and without fuel, respectively (w/o).

6.2 Safe storage of nuclear submarines

The steadily worsening technical condition of the laid up nuclear submarines has led to a number of temporary safety measures. These include attempts to keep the vessels afloat by the constant pumping of compressed air into the hulls, welding of bottom seacocks and periodic docking. In order to prevent leaks of radioactivity from the reactor core, the reactors are treated with self-sealing solutions.[478]

These measures minimise the risk of spontaneous chain reactions in the nuclear fuel through accidental contact with sea water. Nevertheless, there is a significant risk of leaks of radioactivity should the submarine sink. The reactors of vessels that have not been defuelled must be cooled periodically by circulating coolant through the primary circuit. This is achieved by supplying electrical current from a land-based source or from the vessel's own diesel generators or batteries. If all of these power sources should fail in the wintertime, there is a risk of the coolant freezing in the primary circuit and thus damaging the fuel assemblies, making them difficult to remove at a later date.

The safety measures that have been applied hardly include monitoring the condition of the nuclear fuel in the reactor. Hence it cannot be discounted that accidents or leaks of radioactivity could occur in future defuelling operations. The reactors themselves are in markedly worse condition than those on operational vessels, for there is more humidity and variations in temperature as well as the risk of sea water entering the hull. Compressed air is pumped into the hulls to prevent them from sinking. Corrosion is another problem for laid up submarines.[480] Steps have been taken to prevent sea water from entering reactor compartments, and pipes and cable ports are sealed with a special putty.[481]

Laid up nuclear submarines have only one third of the crew used on operational submarines, that is, less than 40 men. Overall, the Northern Fleet has about 2 000 people stationed on the laid up submarines, operating on shifts. The crew members often lack the necessary training or are assigned to a laid up submarine either because they are lacking in competence or are unfit to serve on an active vessel. Thus the lack of competent, qualified personnel increases the possibility of emergency procedures not being executed correctly in the event of a serious incident.[482]

The work of removing spent nuclear fuel from laid up submarines is proceeding very slowly. This is partly because of a lack of proper equipment, and partly by limitations of transport and storage facilities. Since the early 1990s, the Northern Fleet has been responsible for funding the forwarding of spent nuclear fuel to the reprocessing plant RT-1 in Mayak.[483] Hence the Northern Fleet prioritises the refuelling of operational submarines over the defuelling and decommissioning of inactive vessels. In the entire period between 1988-1995, only ten Northern Fleet submarines have been defuelled.

6.3 Dismantling of submarines

The Russian Navy bears the chief responsibility for the dismantling of its nuclear submarines. The Navy has ownership and is also responsible for safety. This is true despite the fact that a number of documents and decrees charge the State Committee for Defence Industries, Minatom and the Ministry of Finance with the responsibility of handling of spent fuel and radioactive waste from decommissioned submarines. The Navy's primary responsibility is to ensure the safe transport and temporary storage of reactor compartments and nuclear waste.[484]

There are several reasons for the unresolved problems of areas of responsibility and that decommissioning is proceeding so slowly. Firstly, the Navy does not wish to relinquish control of its submarines without being paid for them. Secondly, the yards that have been charged with the work of dismantling lack the necessary equipment. There is a severe shortage of storage for the large amounts of radioactive waste that the work will generate, and suitable transport containers are in short supply.[485] All of this results both in a longer lead time before the inactive submarine is finally processed at the shipyard and a further accumulation and backlog of laid up submarines.

6.3.1 Economic aspects

The work of scrapping the nuclear submarines is financed by the Navy yards against receiving a partial refund on the revenue from the sale of scrap metal. However this does not apply to the removal of missile and reactor compartments which is financed by the state. Navy yards are permitted to co-operate with commercial institutions and foreign enterprises. They are also given the opportunity to sell the scrap metal on the international market. Until March 1995, tax exemptions were granted for Navy yards selling metals from dismantled submarines.[486]

Official documents and decrees assume that decommissioning nuclear submarines is self-financing, that is, that the participants in the decommissioning work will make a profit on the sale of the salvaged metals. However, Navy yards that decommission submarines operate at a large loss. For example, the decommissioning of the Project 667 A - Yankee class K-241, factory no. 462 in 1993 resulted in a loss of 311 million roubles (1993) for the Zvezdochka yard.[487] Sixty tons of copper, 100 tons of lead and 20 tons of aluminium were salvaged from this submarine and sold.

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Work is underway to remove spent fuel assemblies from the reactor of a Charlie class submarine at the Zvezdochka shipyard. The costs of dismantling the submarine are paid by the shipyards themselves against the shipyard retaining the proceeds from the sale of the scrap metal. The only exceptions are the work to cut out the reactor compartment and the handling of the radioactive waste. These are operations paid for by the Russian state.

The dismantling of a Project 667 A - Yankee class submarine generates 3 300 tons of scrap metal, of which there are 300 tons of stainless steel, 1 100 tons of low magnetic steel, 1 900 tons of ordinary steel, 50 tons of copper, 70 tons of brass, 70 tons of bronze, 30 tons of cuprous nickel, and 5 tons of aluminium.[488] The corresponding figures for a project 667 B - Delta-I class submarine are a total of 2 096 tons broken down into 554 tons of stainless steel, 220 tons of non-ferrous metals, 90 tons of titanium alloy, 95 tons of copper wiring and 58 tons of lead.[489]

The Sevmash yards in Severodvinsk, charged with the task of dismantling the titanium-hulled submarines operate at an even greater loss per unit than Zvezdochka. The shipyard management estimate a loss of one billion roubles for the decommissioning of the Project 705 - Alfa class submarine K-463 (factory no. 915). Sevmash receives no tax relief on its foreign sales of metals. For the moment, the export tax on titanium alloys is set at 1 900 USD/ton, while the world market price is 1 000 USD/ton.[490]

With the current Russian industrial structure, real revenue from the sale of scrap metal can only be generated through export. Probably only the non-ferrous metals will be of interest to foreign buyers owing to the difficulty of smelting the tempered steel hulls. Until now, only Greece, Finland and China have bought ferrous scrap metal.[491] When dismantling nuclear submarines, special handling is required for large amounts of poisonous materials that have been used in the submarine. A submarine of the Project 667 B - Delta-I class is reported to contain 830 tons of noxious waste, of which 22 tons are battery acid.[492] No economic guarantees have been given by the state for the responsible handling of this waste.

There are much higher costs in dismantling the relatively few titanium-hulled vessels than in dismantling submarines with hulls made of tempered steel. This is because a titanium hull requires more time to dismantle and more advanced equipment.[493] Furthermore, it would appear that the Russian defence industry prefers to keep the metal itself.

The indications are that it will prove impossible to finance the decommissioning of nuclear submarines through the sale of scrap metals. Consequently either the Russian state or other agencies must be prepared to render large scale economic assistance to this work.

Photo, 50 kb.
This scrap metal comes from a nuclear submarine that was dismantled in Severodvinsk. One Yankee class nuclear submarine generates 3 300 tons of scrap metal.

Photo.
The naval yards in the closed city Severodvinsk west of Arkhangelsk carry out maintenance operations on active nuclear submarines as well as decommissioning procedures on older nuclear submarines. Severodvinsk is also the only place in Russia where new nuclear submarines continue to be built.
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6.4 Parties to the work of dismantling submarines

Many differing parties are involved in the decommissioning process. This is true both for the theoretical side of the work as well as the more practical aspects of it. Participants include the former design bureaus, which have been involved in the development of nuclear submarines, the different northern naval yards and a whole range of official and semi-private institutions. New concerns have also been created by the State Committee for Defence Industries.

Theoretical planning has been put forth by the central design bureaus such as Rubin Central Design Bureau in St. Petersburg, Lazurit in Nizhny Novgorod and NIIPTB Onega which is the main institution for submarine repair. War Dept. No. 54034 in St. Petersburg, VNIPIET, bears the responsibility for naval construction and the Krilov Central Scientific Research Institute is the main institute for building naval vessels. CDB-Design Bureau is responsible for the development of reactor technology for Russian nuclear submarines while Test Design Bureau for Machine Building (OKBM) in Nizhny Novgorod has developed the plans for long term storage of reactor compartments in the northern regions.[494]

The St. Petersburg based Eko-Bio corporation has issued comprehensive plans for decommissioning nuclear submarines at a planned cost of 4 billion USD. Funding would be secured from western financial institutions and revenue generated by metal sales. The plans cover all phases of decommissioning up to and including storage of the radioactive waste. The Eko-Bio plans stand little chance of being put into practice.[495] Plans for industrial co-operation in decommissioning of nuclear submarines have been established between Energiya and the Norwegian company Kværner Moss Technology as. These plans are also purely on paper and stand little chance of attracting the necessary financing.

For the practical work the Ekon corporation is an important player. Ekon is based in Severodvinsk and was established on October 22, 1992 with a number of smaller concerns as stockholders: Zvezdochka shipyard (Severodvinsk), Remkon (Moscow), Sudprom (Moscow) and Severnaya korabelnaya kompaniya (Murmansk). Though these companies are not state run, they are under the leadership of men who belonged to the highest strata of the Russian Navy. Up until now, Ekon has been responsible for the decommissioning of three nuclear submarines at Severodvinsk.

The actual dismantling of Russian nuclear submarines is carried out at the Severodvinsk shipyards Zvezdochka and Sevmash, and at the Kola based yard of Nerpa. Some of the work is also parcelled out to naval yards No. 10 Shkval and No. 35 Sevmorput. Each yard has different tasks in the process of dismantling the different submarine classes.

The Zvezdochka yard is working on dismantling the Project 667 A - Yankee-class as well as some first generation Project 675 - Echo-II class submarines. In all, Zvezdochka has scrapped five submarines. These submarines were designed by Rubin Central Design Bureau and it is thus this body that has been assigned the task of co-ordinating their dismantling. In 1995, a total of 70 nuclear submarines were decommissioned (38 in the Northern Fleet and 32 in the Pacific Fleet) that had been designed and developed by the Rubin Central Design Bureau.[496]

Dismantling a Yankee class submarine takes 630 000 man hours. This includes a complete cutting up of the hull and preparing the reactor compartment for transport. The cost in 1995 terms was 22 billion roubles. The capacity at Zvezdochka is for four to five submarines per year on the precondition that the existing equipment for removal and transport of the nuclear fuel is functioning properly.[497]

Photo, 59 kb. Photo, 46 kb.
The decommissioning of Russian nuclear submarines is largely carried out manually in that the workers, as for example this man at the Nerpa shipyard, cuts into the hull using a blowtorch. The vessel pictured here is a Victor-I class submarine. The decommissioning of a larger Delta-I class submarine is estimated to take 32 000 working hours.

There are plans to increase the capacity of Zvezdochka and the Kola Peninsula based Nerpa yard. Decree no. 644-47 of August 31, 1993, concerns this proposed expansion as well as the building of more dock facilities and increasing the storage capacity for spent nuclear fuel. Russia is currently negotiating with the United States on co-operative projects to increase dismantling capacity. American cutting tools have already been delivered to the Nerpa yards, including a plasma torch for Nerpa and several other tools to the Severodvinsk yards.[498] From the point of view of the United States, it makes sense to deliver equipment which facilitates the removal of the submarines' missile compartments. The construction of a decommissioning facility at Nerpa began in 1993 and is scheduled to be completed in 1996. However, due to economic problems, the work has been delayed by a few years.[499]

The dismantling of titanium-hulled submarines takes place at the Sevmash yards in Severodvinsk. At present, work is ongoing to dismantle the Project 705 - Alfa class submarine K-316 (factory no. 105). The submarine K-463 has already been dismantled, and its reactor compartment taken to Sayda Bay.[500] Two other submarines of this class are ready to be processed (factory nos. 905 and 106).[501] A titanium-hulled submarine of the Project 661 - Papa class is also moored in Severodvinsk waiting to be dismantled at Sevmash.

6.5 Stages in decommissioning

After transfer to the naval yard, the hull is cut into three parts. The submarine's missile compartment is then removed, in compliance with the terms of the disarmament agreements. This work is carried out in dry dock. Upon removal of the missile compartments, the remaining fore and aft parts of the submarine are welded back together. This is done in order to keep the submarine afloat while waiting for capacity for the removal of the nuclear fuel and securing of the reactor to become available. The submarines can be kept floating for several years in this manner while waiting for a dismantling slot to open.[502] The next step in the process is the removal of nuclear fuel from the reactor. This is described in Chapter 7.

6.5.1 Preparation of the reactor compartments

The nuclear submarine is brought into dry dock and the process of cutting out the reactor compartment proceeds. It is estimated that the procedure of decommissioning of a Project 667 B - Delta-I class submarine will take 32 000 man hours.[503] There are dry docks for this kind of work at the Severodvinsk and Nerpa yards, and there are plans to build a similar dock at naval yard no. 10 Shkval.

Photo, 67 kb.
This Yankee class submarine is being opened up in one of the land-based dry docks at the Zvezdochka shipyard in Severodvinsk. The submarine must be in dry dock in order to remove both the missile section and the reactor compartment.

Photo, 33 kb.
The terms of the START-II disarmament treaty require that the missile sections of the strategic nuclear submarines must be removed before the submarine can be considered among those that have been taken out of active service. This requirement has resulted in a situation where a number of the Yankee class submarines in Severodvinsk today remain afloat in two separate pieces. Here, the missile section has been removed and the vessel's forward and aft parts have been welded together again. The reactor compartment containing two reactors with their fuel assemblies remains inside the vessel's hull. As can be seen, sea water is penetrating through the crack between the two parts, thereby hastening the onset of corrosion and impairing the submarine's ability to float.

Preparing the reactor compartments for transport and long term storage can be accomplished in three different ways:

• The submarine is cut up to leave an extra compartment fore and aft of the reactor compartment;
• Only the reactor compartment is removed, to which pontoons are then fastened;
• The reactor compartment is filled with the buoyant substance polisterol, to help keep the reactor compartment afloat.

All three methods are intended to ensure that the reactor remains afloat for the purposes of transport and floating storage. The Russians claim that all three methods are guaranteed to keep the reactor compartments afloat for a minimum of ten years.[504]

The use of polisterol eliminates the need for blowing compressed air into the compartments.[505] This method has been developed by the state company Econol for the Rubin Central Design Bureau, and is a project supported and financed by the Russian Navy. If it is actually put into practice, naval yard no.10 Shkval in Polyarny will be assigned the work.

Illustration, 16 kb.
Drawing for a planned experimental plant for filling ballast tanks of nuclear laid up submarines with polistirol to ensure their floating ability

6.5.2 Dismantling submarines with damaged reactors

Six of the nuclear submarines that have been taken out of service have had accidents in which the fuel assemblies were damaged. Consequently, these vessels cannot be decommissioned in the normal way. Four belong to the Pacific Fleet and two to the Northern Fleet. The two Northern Fleet vessels are K-192, factory no. 533 (Project 675 - Echo-II class) and K-64, factory no. 900 (Project 705 - Alfa class). The reactor compartment of the latter has already been removed. The four vessels from the Pacific Fleet are factory no. 175 and factory no. 180 of the Project 675 - Echo-II class, K-314, factory no. 610 of the Project 671 - Victor-I class, and K-66, factory no. 142 from the Project 659 T - Echo-I class.[506] The design bureau Malakhit has developed plans for the decommissioning of these submarines and has applied to the Russian Navy for funding.[507]

Rubin Central Design Bureau also has proposed plans for decommissioning three Project 675 - Echo-II class vessels. These plans call for the use of specialised equipment to remove the nuclear fuel from the submarines. Removal of fuel from factory no. 175, a damaged Echo-II class vessel is deemed impossible.

After decommissioning, the reactor compartments of these vessels will be placed in interim storage with other more ordinary reactor compartments in tunnels in the Ara Bay for a period of up to 100 years.[508] An exception to this is the reactor compartment of K-64, Project 705 - Alfa class which will be stored at the dry dock in Gremikha.[509]

There may be other laid up submarines besides these six from which the nuclear fuel cannot be removed in the usual way. There are also six reactor compartments still containing their nuclear fuel that were dumped in the Kara sea. If these reactors are ever raised, they too will have to be decommissioned and stored in the proper fashion.[510]

In addition to those vessels where reactor accidents have precluded normal defuelling procedures, the submarine K-162, factory no. 501 (Project 661 - Papa class) also presents problems. It is presently laid up in Severodvinsk. The K-162 is an experimental prototype from which the nuclear fuel cannot be removed in the same way as the more common reactor types. The equipment for defuelling the prototype has been lost and must be re-manufactured. As many as 50 fuel assemblies are allowed to remain in the reactor, in preparation for long-term storage.[511]

6.5.3 Tansportation of reactor compartments

Reactor compartments which are processed in Severodvinsk and Nerpa are towed to Sayda Bay where they are moored to piers for temporary storage until a permanent facility can be established. In 1994, four reactor compartments from Severodvinsk were towed here and another two were towed in the autumn of 1995. The distance from Severodvinsk to Sayda Bay is approximately 350 nautical miles. During the winter, all of the White Sea and parts of the eastern Barents Sea off the Kola Peninsula is ice covered. The reactor compartments are towed directly in the water, rather than aboard barges or other types of vessels. The danger of them sinking while under tow is greater than when moored in the Severodvinsk harbour basin. Usually two partial hulls with their reactor compartments are towed simultaneously.

One reactor compartment that was towed away in 1994 was loaded with solid nuclear waste. The same practice is anticipated for a number of reactors in the time to come. Again, it is the lack of storage capacity for solid radioactive waste in Severodvinsk that precipitates these kinds of measures. Furthermore, the Severodvinsk town administration have ruled that the total amount of radioactive waste stored in the city may not rise above present levels.[512]

6.5.4 Plans for long term storage of reactor compartments.

The reactor compartments are kept afloat in the Sayda Bay pending the establishment of a permanent storage facility. No decision has yet been made as to how and where this storage is going to be constructed. Several possibilities have been proposed and investigated.

Photo, 14 kb.
The reactor sections from decommissioned nuclear submarines are towed over water to these piers at Sayda Bay where they will be temporarily stored until a long term storage facility is established. At the very left edge of the picture is the reactor compartment from an Alfa class submarine. The three other hulls come from (left to right) Hotel class, Charlie class and Echo-II class vessels. Reactor compartments that are stored in this way may be kept afloat for an estimated ten years.

Illustration, 8 kb.
The illustration shows the planned way of handling reactor sections of decommissioned submarines. The first stage asummes cutting out of the reactor section (1). Then the reactor sections are loaded onboard transport vessel which delivers them to Ara-bay (2). In Ara-bay they are taken onshore (3) and placed into the tunnels for long term storage (4).

The option of utilising one or more of the 400 meter tunnels in the Ara Bay on the Kola Peninsula for long term storage has received the most consideration. The tunnels were originally intended to conceal and shield strategic nuclear submarines, but were never completed. According to the current proposal, up to 100 reactor compartments could be stored in the tunnels.[513] Other sources claim that the plans call for storage of up to 130 reactor compartments in the Ara Bay tunnels.[514] Before the reactor compartments enter the tunnels, the pontoons both fore and aft will be removed. All currently accessible reactor compartments could be placed inside these tunnels by the year 2007.[515]

A precondition for use is that the tunnels are dry. The project was approved by the Soviet Minister of Defence in 1990 and the first reactors were to be in place by 1994.[516] The Chernomorskaya yard in Sevastopol was to build derricks to lift the reactor compartments from barges to the tunnels. Storage permits were issued allowing storage of the reactor compartments in the tunnels for 70 to 100 years. After this period of time, radiation levels would have been significantly reduced allowing the compartments to be completely dismantled and the resulting scrap metal stored as ordinary solid nuclear waste.[517]

Plans for utilising the Ara Bay tunnels for long term storage has met with criticism from many Russian agencies. The possibility of flooding in the tunnels resulting in leaks of radioactivity has been the cause of greatest concern. The storage facility would then be in conflict with Russian environmental regulations. Current laws prohibit the storage of radioactive waste in locations where there is a significant risk of leakage into the sea.

To safeguard against leakage from the tunnels at Ara Bay, the possibility of storing reactor compartments in the disused strip mining pits of Nikel has also been considered. This solution presupposes the building of a railway or a roadway of considerable size all the way from the coast. Andreeva Bay in Zapadnaya Litsa has also been considered as a possible long term storage location for reactor compartments. Both the latter locations entail considerable construction projects and the blasting of new tunnels, possibly even building large concrete structures.[518]

A final possibility is storage in the permafrost at Novaya Zemlya. There are proposals to blast 2-3 kilometre long canals inland from the coast. The reactor compartments would then be towed up the canals. Once the canals had been filled with reactor compartments, dams would be built and the remaining water pumped out. Finally the reactor compartments, and possibly other types of radioactive waste, would be covered with sand and rock. According to Russian authorities, the permafrost will prevent the escape of radiation.[519]

6.6 Radio ecological problems of dismantling

A nuclear submarine which has been prepared for dismantling contains that are radioactively contaminated to various degrees. More than 95% of the contaminated material comes from the reactor, representing approximately 7 % of the submarine volume.[520]

Usually, most of the liquid radioactive waste is drained from the reactor when the fuel assemblies are removed. The liquid waste constitutes about 200 m³. Twenty cubic metres comes from the primary coolant circuit, 4 m³ from filters, and 170 m³from biological shielding tanks in the reactor compartment.[521]

Considerable amounts of radioactive waste in the reactor compartment are concentrated on the inner surfaces of pipes and various tanks. Approximately 90% of the radioactivity is removed from the primary coolant circuit when the system is flushed after the initial draining. The radioactive waste thereby remains in liquid form. The flushing of the primary cooling circuit produces about 100 m³ liquid waste with an activity of up to 3.7 TBq/l (10² Ci/l).[522] When decommissioning a twin nuclear reactor compartment, an additional 800 m³ of liquid nuclear waste is generated.[523] The reason for the large volume of liquid waste is that water is used to continually flush the equipment and reactor parts to prevent them from becoming unnecessarily contaminated.[524]

Investigations of reactor compartments 3-5 years after removal of the nuclear fuel show that 90% of the remaining activity is represented by long life isotopes, 10¹³ to 10¹⁵ Bq in total. The primary cooling circuit contains as much as 4 x 10¹⁰Bq in transuranium elements. Because of the varying reactor designs between the different classes of submarines, these values can vary to a large extent. Examination of hulls in which at least three compartments were remaining show gamma radiation higher than the permitted threshold values.[525]

There is no operational treatment plant for liquid radioactive waste at either Severodvinsk or Nerpa. The civilian icebreaker base Atomflot in Murmansk has one facility with an annual capacity of 1 200 m³. A trilateral Norwegian-American-Russian project is underway to expand this capacity to 5 000 m³ yearly. The Russian Pacific Fleet possesses equipment for treating liquid radioactive waste, and a similar solution is planned for Severodvinsk.[526] The technology in such treatment is based on transferring the activity in the liquid medium to filters which can be treated as solid waste, but in much smaller volume.

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This purification plant for liquid radioactive waste belongs to Atomflot. It has an annual capacity of 1200 m3 of contaminated water. The capacity is expected to increase to 5 000 m3 annually as a result of a Russian-American-Norwegian co-operative project.

Endnotes