«Alternate options of nuclear-powered submarine B-159 salvaging».

Transcription

1 «Alternate options of nuclear-powered submarine B-159 salvaging». Dorofeev V. Yu., Deputy of General Designer, Chief Engineer PC «St-Petersburg Marine Design Bureau Malachite», Russia 1. Introduction In 1948 had been established design bureau «Malachite» n the Soviet Union. In the bureau works had been expanded on submarines with air-independent power plants. In 1952 by engineers and designers of Malachite were started designing of the first Soviet submarine, Project 627А, which had got code denomination «November». In 1955 head ship had been laid in Severodvinsk on berth of yard Northern machine-building enterprise. In 1958 after the whole cycle of trails was over Navy flag had been raised onboard ship and it was included in stock of members, belonging to the Soviet Navy Forces. According to Project 627А all in all 13 ships had been constructed in the Soviet Union. One of them was nuclear-powered submarine constructed in 1963 with tactical number «B-159». The submarine had serviced faithfully for 25 years. In 1988 the main power plant was decommissioned and converted in nuclear safety conditions, the submarine «B-159» was conserved and transported in point of temporally deployment to wait for utilization process. In August, submarine «B-159» of Project 627А during towing to utilization site sunk on depth of 250 meters near island Kil dyn in Barents sea. The main specifications of submarine «B-159» are as follows: - overall length, m overall width, m height up to superstructure deck, m maximum height, m displacement, tons: normal 3125 underwater

2 2. Option of nuclear-powered submarine salvaging. In 2004 Design Bureau «Malachite» developed technical proposals on salvaging submarine «B-159». I venture to state shortly technical essence of proposed salvaging actions. Proposed complex for salvaging consists from surface platform and submerged module. Salvaging complex is intended for salvaging of submarine «B-159», but could be used also for salvaging submarines, having close masses and sizes of the submarine. Surface platform is non- self-propelled vessel of catamaran type. Two hulls of the vessel are connected in ends by bridge links. In the space between hulls submerged module is installed with grips. The grips are arranged along hull length in accordance with their further installation layout over sunken submarine. Each grip through block-and-tackle system is connected with two surface platform winches. Centering of submerged module relative to sunken «B-159» is provided by guide ropes, brought over stocks of submarine stock device ShU-200. Frame structure of submerged complex rigidly fixes grip positions along length and allows mutual displacement relative each other by vertical direction on 1.2 m. On the frame submerged hydraulic unit is mounted and block of hydraulic distributors to 2

3 provide work of hydraulic cylinders. Total lifting force provided by load-lifting device is 4500 tons. Onboard surface platform are accommodated power module, accommodation unit, necessary supplies and auxiliary equipment. Main specifications of surface platform are as follows: Overall length, m 82.5 Overall width, m 38.8 Distance between hulls, m 11.4 Draft, m without submarine 3.6 with submarine 4.8 Displacement, t without submarine 5600 with submarine 7000 Provided preliminary calculations has shown performability of the proposed option. 3. Options for sunken submarine «B-159» shelter production and installation. Lying on depth 250 m submarine «B-159» with unloaded spent nuclear fuel is a potential source of radiation hazard, and therefore should be subjected to after treatment. There is no alternative. But several ways of after treatment could exist. The same idea was reworded in report «General estimation and possible ways to solve problems, associated with sunken objects in the Arctic region, which contain spent nuclear fuel and radioactive wastes» by academician А.А.Sarkisov in

4 After treatment directions for sea water areas. 1. Leaving of objects on the same site: without additional protection; with additional protection; 2. Objects salvaging - utilization; - over entombment in the seas. «Malachite» specialists have reviewed different options of submarine «B- 159» leaving on bottom soil with additional protection. Submarine isolation from environment could be provided by several ways: A) To fill up submarine by soil (sand, stones, cement); B) To fill submarine by concrete; C) To mount over submarine hangar from ferroconcrete blocks ; D) To form over submarine hangar from monolithic concrete; E) To lower over submarine manufactured in advance overland ferroconcrete or metal hangar ; F) To remove soil from under submarine bottom and provide possibility for submarine to be buried lower bottom level. To estimate methods of isolation let us review qualifying standards for construction and shelter mounting technologies in place of submergence: 1. used during mounting facilities and equipment should be approved by construction practice for floating marine technical erections; 2. works should be provided without usage of deep divers labour ; 3. duration of operation for shelter mounting reasoning from reliability of favorable weather forecast should not exceed 5 days ; 4. shelter structure should allow possible submarine salvaging in future. 4

5 Got specifications of options are given in Table 1. Table 1. Specifications for shelter of different type Shelter type Overall dimensions, m Возможность Necessity to Mass, t construct of Length Width Height подъема special vessel АПЛ, м A - dirt filling / No Not required B concrete filling No Required C assembly of ferroconcrete Yes Required blocks D hangar from monolithic Yes Required ferroconcrete E floating ferroconcrete Yes Not required hangar F trench digging-in No Required Based on outspoken requirements options of submarine filling up by soil, filling by concrete and burying over sea bottom had been excluded from reviewing. After preliminary reviewing there were rejected also options of shelter forming out of ferroconcrete blocks manufactured in advance (option C) and monolithic concrete, being cast just on the submergence site (option D). Option from in advance formed ferroconcrete blocks (option C) is well mastered during construction of embankments and waterside structures. The essence is in manufacturing over shore giant massifs, being hollow inside, closed from the 5

6 bottom and sides and having internal bulkheads. After afloat delivery to site of massif installation, it is flooded, submerged and afterwards filled by stones and concrete. This option was rejected, because of the following reasons: - necessity of solid berth basement preparation with soil compression on depth of 250 m ; - no industrial technology of accurate block installation on large depth with further seam capsulation. Shelter forming out of monolithic ferroconcrete, founded on submergence site (option D). This option was rejected, because of the following reasons: - no technology of underwater concreting on depths more than 50 m ; - plug formation in pipes more than 250 m, delivering mortar; - strict time limitations to provide continuity of filling process. The most perspective is option over submarine manufactured in advance ferroconcrete or metal hangar. The experience has been accumulated during mounting of water-permeable erections for dam construction, protecting St-Petersburg from flooding. Thousandton ferroconcrete construction was towed afloat to installation place and then was submerged on bottom by water flooding of buoyancy tanks. 4. Options for shelter construction. By specialists of PC «SPMDB «Malachite» the following options of shelter structures had been worked over: 1) ferroconcrete hangar; 2) steel hangar; 3) composite hangar. 6

7 1 hangar 5 catamaran hull 1- ангар, 2 - седло-упор, 3 - траверса, 4 - транспортные растяжки, 5 - корпус катамарана, 6 - амортизатор пневматический, 7 - грузовая балка 2 saddle-stop 6 pneumatic shock-absorber Комплекс 3 traverse СПК, состыкованный 7 с load ангаром-укрытием beam 4 transport guy lines Salvaging Complex attached to hangar-shelter Ferroconcrete shelter is hangar with vertical walls and cylinder (parabolic) roof. End walls could be either circular or flat. Calculating reduced wall and roof thickness 200 mm and basement thickness 300 mm mass of the shelter is 3000 tons and negative buoyancy would be about 1900 t. It is evident, that for transportation and installation of assumed shelter could serve written above complex for salvaging. At that instead of large-sized grips load traverses are installed, to which ferroconcrete hangar is fixed. Attachment of hangar and salvaging complex is executed in submersible dock. Sea part of installation operation is the same in provision as operation of submarine salvaging. 7

8 View Вид А А 1 floating 1- crane корма aft плавкрана, 2 - ангар, 3 - грузовая 4 strapping рама, 4 - стропы, 5 - несущая балка ангара, 6 - затонувшая ПЛ 2 hangar 5 hangar supporting girder Возможная схема строповки ангара ПК С.Юдин 3 loading frame 6 sunken submarine Possible strapping layout of vessel "S. Yudin hangar. If hangar is made from steel with protective coating and, if sizes are left the same, mass would be about 1200 t. In the case hangar transportation is possible aboard specially manufacture pontoon, while installation over sunken submarine is provided by powerful floating crane with capacity more than 1200 t. For the purpose crane-mounting vessel Stanislav Yudin of Project 2026, manufactured by Finnish firm «Värtsilä». As the lifted structure has considerable mass, while by geometrical specifications is comparable with crane vessel, therefore additional supplement is needed to exclude hangar rotation on hook and its possible thrusting upon. In addition it is necessary to solve a problem of hangar docking guidance in submerging process over sunken submarine. 8

9 T=7,5 м Мост средний Middle bridge Ангар Hangar Pressure Прочный hull корпус left левый Прочный корпус Pressure правый hull right 4500 ВЛ WL Балластные Ballast цистерны tanks CL Д П BP ОП Схема укрытия с композитным корпусом. Поперечное сечение. Diagram of coverage by composite casing. Cross-section. To exclude usage of expensive salvaging complex or crane-mounting vessel during transportation and installation of shelter it is expedient to use floating hangar with composite hull. In the case along ferroconcrete hull steel cylinders are fixed, serving as buoyancy tanks. Buoyancy tanks are computed for pressure corresponding to depth 250 m. light ballast tanks are located under them. Ballast tanks are flooded, when shelter transfer from surface to submerged state. Buoyancy tanks flooding is provided to make reasonable negative buoyancy in the process of submerging and after hangar is located over sunken submarine to make full negative buoyancy and to deepen hangar in soil. Shelter has in underwater state zero buoyancy and does not need powerful floating crane for submergence. Meanwhile, during lowering shelter should be kept by strapping to guarantee lowering process stoppage before shelter contacts bottom in order to provide shelter final orientation. 9

10 Comparison specifications of salvaging complex and shelter options. Options of shelter Complex Floating Specifications for hangar with Concrete hangar Metal hangar salvaging composite hull Length, m Width, m Maximum height, m Draft, m Displacement, t Platforms - Complex for salvaging Barge for transportation, crane vessel with tonnage capacity 1500 tons. 2 pontoons with area each 100 m 3 4 pontoons with area each 100 m 3 Approximate cost, including design, construction and sea operation 10

11 Conclusions 1. Executed works has shown possibility to produce and install a shelter for sunken ship «B-159». 2. Among the most acceptable for further development are the following options: - steel hangar with anticorrosive coating, being loaded with the help of floating crane; - ferroconcrete hangar with built-in steel pontoons and solid tanks, providing buoyancy and navigability, which provide towing by sea and submerging over sunken submarine. 3. By complexity both operations salvaging and sheltering are equivalent. 11