RU2140108C1 - Method and system for recovery of nuclear- powered submarines - Google Patents

Abstract

FIELD: recovery of nuclear- powered submarines, ships, tanks, and other large vehicles. SUBSTANCE: reactor core, filters, radioactive coolant circuits, and weapon are removed prior to decontamination and after decontamination all pieces of equipment are dismounted. Then submarine hull is conveyed to intake chamber of underground tunnel wherein nonmetal materials are removed by heating hull to 500 C. After that, hull is heated to 700 C and conveyed as it melts to melting chamber located in underground tunnel behind intake chamber until it fully melts up. Powdered carbon is injected in molten metal surface in accumulation chamber mounted in bottom part of tunnel. System implementing this method has two inclined underground tunnels. First tunnel accommodates intake, melting, and accumulation chambers; the latter is located in bottom part of first tunnel, heating device is mounted in intake chamber and melting device, in melting chamber; metal pouring device is made in the form of discharge chute. Second one is transport tunnel accommodating metal admission molds. EFFECT: reduced time and labor consumption, reduced storage time of power units, improved environmental safety. 4 cl, 2 dwg

Description

 The invention relates to a method for the disposal of nuclear submarines (NPS). Its wide versatility allows it to be used also for ships, tanks, torpedoes, missiles and other objects.

Well-known domestic and foreign methods of dismantling submarines are characterized by the following features (see the international scientific seminar "Problems of decommissioning and disposal of nuclear submarines." Abstracts of June 19-22, 1996, M.):
1. The technology for the dismantlement of nuclear submarines provides for mandatory cutting of hull structures and ship equipment, not suitable for further operation in the national economy, in ship scrap.

 2. A wide range of materials used and their thicknesses, complex configurations in sections of cut (cut) submarine hull structures and oppression make the technology of cutting the hull one of the most difficult and time-consuming jobs. At the same time, the developed and applied technologies for cutting the body (gas, plasma, laser and hydraulic cutting) are generally imperfect, time-consuming and polluting the environment. It is difficult to apply metal cutting by an explosion, because it requires accurate fit of the “cord” to the nuclear submarine design profile, and the necessary work safety is not provided. The cleanest cutting process is mechanical cutting, but its capabilities for these structures are very limited.

 3. The high induced radioactivity of the reactor compartment (RO) for the entire period of operation of the ship’s nuclear installation predetermines its long-term (50-100 years) storage in closed tunnels or fenced areas until the radiation level decreases, at which it is subsequently possible to cut the compartment into scrap material. To ensure long-term storage of RO, it will be necessary to create special storage facilities with access roads, lighting and monitoring systems. In addition, prepared compartments must be transported to the place of their long-term storage, which will require the creation of special vehicles and access roads.

 4. Work on the cutting of radioactive equipment and structures RO are potentially dangerous. When cutting radioactive metal into ship scrap, it is impossible to create protective barriers that protect the environment and workers.

 5. The high complexity of the work, for example, the complexity of the dismantling of nuclear submarines, not counting the smelting of scrap, is 700 thousand man-hours, while prepared for long-term storage of radioactive waste will subsequently also require labor for its disposal.

 6. The water areas of the enterprises allocated for the dismantlement of nuclear submarines occupy large areas, and the numerous and hazardous production wastes in the process of disposal pollute the environment, causing irreparable harm to all nature.

 As an analogue, one can cite the most elaborated method of nuclear submarine dismantlement (E. A. Gorigledzhan, "Basic directions for solving the problem of the dismantlement of Russian nuclear submarines"), presented in the collection of the international scientific seminar "Problems of decommissioning and disposal of nuclear submarines." Abstracts, June 19-22, 1995, Moscow, p. 14-15.

The main distinguishing features of this method are:
- a section of the reactor compartment (RO) from the bow and stern blocks;
- RO sealing in a robust case and its tightness test;
- LO loading onto a special transport crane crane (TKS) with a crane lifting capacity of about 1600 tf and its transportation to long-term storage facilities of the tunnel type;
- transshipment of RO from the transformer substation to ship carts and sending them to sediment for 50-70 years;
- cutting the remaining bow and stern blocks into scrap metal or welding them together and sending them to temporary storage after dismantling the equipment.

The above method of dismantling submarines, in addition, requires a significant amount of additional work:
- retrofitting of factories with specialized sections for cutting hulls (nuclear submarines) and waste processing;
- the creation of advanced technologies for cutting hulls (laser, hydro-jet, plasma);
- carrying out a wide range of activities to ensure environmental protection, etc.

 Application N 94018126, G 21 F 9/34, 1994, RU, "Method for the industrial disintegration of ships and vessels with nuclear power plants" provides for the decontamination of units and components of a nuclear power plant (NPP), cutting the hull into at least three parts with the allocation of the part, including nuclear power plants. Then this part of the hull with the nuclear power unit is subjected to cutting into parts in a specially equipped chamber using linear, directed to the center of the installation of explosions. Further, these parts are subjected to decontamination due to special remelting with the addition of an appropriate flux.

 When melting a radioactive metal, according to the authors, highly radioactive slag, radioactive gases and deactivated metal are obtained. However, blasting the radioactive part of the hull for such complex large-sized ship structures is an unpredictable, uncontrollable process and, most importantly, not acceptable from the point of view of safety. The specified method of cutting can be used for small or fragmented structures.

 Closest to the proposed method is the method described in the application N 94005896, IPC G 21 F 9/30, 1994, RU, "A method for processing dismantled radioactive contaminated equipment and a complex for its implementation. This method includes fragmentation of equipment, induction remelting in the presence of slag fluxes, followed by separation of radioactive contaminated slag and curing of the metal, with liquid decontamination assembled before fragmentation of the equipment, and re-decontamination after fragmentation fragment deactivation Before induction smelting, thermal deactivation of the fragments is also carried out by burning combustible (non-metallic) materials, melting low-melting metals in the separation of radioactive oxides and calcining the remaining metals, followed by removal of radioactive contaminated scale, while the calcined metals are sorted by type and group and sent to induction remelting, and the gases formed in the process are taken to neutralization and cleaning.

 The method involves liquid and thermal deactivation, the use of slag fluxes, which generally significantly reduces the radioactivity obtained after remelting the metal. However, with this method, the operation of fragmenting radioactively contaminated equipment to sizes convenient for loading into a transport container is necessary. Remelting fragments is provided by induction.

 The need for this fragmentation in relation to the dimensions and masses of nuclear submarines, ships and ships does not eliminate the main drawbacks of cutting hulls, that is, it requires the creation of specialized sections for a potentially dangerous work, as well as a large range of environmental protection works, thereby reducing the efficiency of the process.

 The objective of the present invention is to increase the efficiency of dismantlement of nuclear submarines (reducing the complexity and duration of disposal, eliminating the long-term storage of energy compartments, expanding the range of utilized products), ensuring environmental safety.

The specified technical result is achieved by the fact that in this method of disposal of nuclear submarines, including decontamination of equipment, removal of non-metallic materials by gasification, remelting of metal in the presence of slag additives, followed by separation of the resulting radioactively contaminated slag from molten metal, casting and curing of metal and slag before by decontamination of the equipment, the reactor core, filters of the I and II circuit, radioactive water and weapons are unloaded, and after decontamination, installation of the equipment, then the submarine’s hull is fed into the underground tunnel, into the receiving chamber, in which non-metallic materials are removed by heating the hull to a temperature of 500 ^o C, after which the hull is heated to a temperature of 700 ^o C and moved as its end part melts into the melting chamber located in the underground tunnel behind the receiving chamber, until complete melting, while during the melting the surface of the molten metal in the storage chamber located in the lower part of the tunnel is injected with powdered carbon th.

 Carrying out the operations of the method in the indicated sequence in the underground tunnel allows you to dispose of the nuclear submarines without preliminary cutting the hull, reduces costs and the duration of the work, increases the safety of the process.

 Carrying out work in these modes in a single cycle eliminates the stages of work associated with the transportation of intermediate products, for example, calcined metals, which also increases the efficiency and safety of the process.

 Well-known metallurgical melting plants (open-hearth, electric, smelting, converter) cannot provide remelting of the nuclear submarine, release and casting of metal in connection with its dimensions, weight and design features, for example, a steel-smelting plasma furnace (see A.D. Kramarov, A.N. Sokolov, Electrometallurgy of Steel and Ferroalloys, M., Metallurgy, 1976, p. 184-186). Units of this type are intended for remelting a metal charge, limited in weight, dimensions and chemical composition by the requirements of GOST 2785-75.

 Thus, the implementation of the method of disposal of large-sized radiation-contaminated objects requires the study of its implementation in specific devices.

 It should be noted that the implementation of the proposed method can be carried out using a whole range of devices connected by a single technological cycle. The complex is also an object of the invention according to this application. The patented method and complex are a group of inventions, united by a single inventive concept, namely they allow highly efficient process for the disposal of large-sized structures, in particular, the nuclear submarine hull, in compliance with environmental safety requirements. The specified technical result is achieved by sharing the objects of the invention.

 The closest in technical essence to the claimed solution is a complex for processing dismantled radioactive contaminated equipment according to the application N 94005896, IPC G 21 F 9/30, 1994, RU.

 The complex for processing dismantled radioactive contaminated equipment contains equipment fragmentation units, induction remelting (melting device), liquid decontamination, thermal deactivation units, including an indirect heating electric furnace (heating device), devices for casting and curing molten metal and slag, and neutralization and cleaning devices gases, nodes of transportation, sorting of metals, preparation of the charge.

 The specified complex serves to implement the method according to the same application, adopted as a prototype of the proposed method, and it has the same limitations that impede the use of the method for the disposal of large structures, in particular, nuclear submarines.

 The method and device, selected as a prototype, allow cleaning and re-melting of utilized equipment to a radiation level, which allows for the return of metals to economic circulation immediately after processing. However, they require preliminary fragmentation of the dismantled equipment, which for objects of such a category as nuclear submarines is a very time-consuming operation, which also does not ensure environmental safety.

 A nuclear submarine dismantlement complex containing a heating device, a melting device, a device for casting and curing molten metal and slag, a device for neutralizing and treating gases, is made in the form of two underground inclined tunnels, in the first tunnel located above the second transport tunnel, there is a reception , a melting and storage chamber, the storage chamber being located in the lower part of the first tunnel, the heating device is located in the receiving chamber, and the melting device is in the melting chamber re, devices for casting and curing metal and slag are made in the form of drain troughs and molds, while the trough for draining molten metal leaves the lower part of the storage chamber into the transport tunnel, and the slurry drain chute from the upper part of the storage chamber into the transport tunnel, in which contains molds for receiving and curing metal and slag, and injectors are located in the upper part of the storage chamber for feeding powdered carbon onto the surface of the molten metal.

 As heating elements of the heating device, fuel-oxygen burners are used located on the inner surface of the receiving chamber, and as heating elements of the melting device are jet plasmatrons located on the inner surface of the melting chamber.

 Carbon blocks are used as the working layer of the lining of the storage chamber.

 The combination of these elements and assemblies in the complex ensures the achievement of the specified technical result, namely, the efficient disposal of large-sized structures, in particular, nuclear submarines, by the method of local face melting.

 The proposed method and the complex for its implementation are novel; from the prior art there are no solutions that similarly solve the problem.

 The proposed group of inventions has an inventive step, since no solutions have been identified that have features that match their distinctive features.

 The proposed solution is industrially applicable, because its implementation will satisfy the need for the disposal of large-sized radiation-contaminated objects by means and methods described in the application materials.

 Thus, the proposed solution meets all the criteria of patentability.

 The essence of the proposed technical solution is illustrated by drawings, where in FIG. 1 shows a sectional view of a complex for the dismantlement of nuclear submarines, in FIG. 2 - section aa.

The complex consists of two inclined tunnels: the first, melting, in which receiving 1, melting 2 and storage 3 chambers are sequentially placed, and the second, transport tunnel 16. The complex also provides:
- device for the neutralization and purification of gases 4,
- gateway sealing flaps 5 and 6;
- a heating device 7 located in the receiving chamber 1;
- a melting device 8 located in the melting chamber 2;
- additive supply device 9;
- carbon powder injectors 10 located in the upper part of the storage chamber;
- a chute discharge 14 molten metal;
- a chute discharge of slag 15;
- molds 17 for receiving molten metal and slag;
- fuel and oxygen burners 18;
- jet plasmatrons 19.

The receiving chamber 1 is provided for pre-heating the hull of the nuclear submarine 13 with the aim of burning and removing impurities of organic origin and then heating it to 700 ^o C.

 The case is heated by burning natural or furnace gas, as well as by using the exhaust hot gases from the melting chamber, similarly to the methods used to heat the charge in a basket (tub) of an electric arc steel furnace.

 Additional heating of the housing should be carried out due to the fuel-oxygen burners 18 located on the inner surface of the receiving chamber 1 in the annular recesses and directed tangentially to the axis of the tunnel. The inner surface of the receiving chamber 1 is lined with refractory material 12. In the upper part of the chamber 1, in the shaft, there is a device for gas neutralization and purification 4. In the melting chamber along the lateral surfaces, in its upper and end parts there are jet plasmatrons 19, power and direction of the jet plasma are controlled by a special telemetric system. For the operation of plasmatrons, an inert gas or natural gas conversion is used.

 To supply a special mixture (additives) in the upper part of the chamber 2 have the necessary feeders 9.

 The storage chamber 3 is located in the lower part of the tunnel, behind the melting chamber and serves to accumulate, portioned or continuous discharge of molten metal through the electromagnetic discharge chute 14 directly into the molds 17 located in the transport tunnel 16. The storage chamber has a lining 11 of carbon blocks, which contributes to lowering the melting point of the melt.

 An example of a specific implementation of the proposed method and complex is as follows.

 At the first stage of nuclear submarine dismantlement, the reactor core, filters I and II of the circuit, radioactive water, weapons, decontamination, dismantling of ship equipment, mechanisms and devices are unloaded and transported in accordance with accepted technology. After carrying out all dismantling operations, the submarine’s hull is lifted along a slipway or transported to the site where the dismantling of shaft lines, rudders, deckhouses and stabilizers is carried out. At the same time, an elastic coating is removed from the body. In the upper part of each compartment, small removable sheets are opened or regular hatches open.

The submarine hull is installed on slipway bogies with the gradual formation of a slope of it at 8-15 ^o deep into the tunnel.

Using a special delay device, the hull of the nuclear submarine 13, under the action of gravity, is uniformly and at a predetermined speed fed into the receiving chamber 1, where after closing the lock sealing flaps 5 and 6 they are heated to a temperature of 500 ^o C by burning natural or furnace gas, as well as by recycling heat of the exhaust gases of the melting chamber 2. During this period, non-metallic materials are burned and removed. Then include additional fuel and oxygen burners that heat the housing to 700 ^o C.

 After preparing the hull of the nuclear submarine 13 for the main process (smelting), it is fed at a low speed into the melting chamber 2. At the same time, by the time the hull enters the chamber, the plasma torches 19 are turned on, by which the feed aft or bow is melted.

 The speed of movement of the hull of the nuclear submarine 13 is strictly synchronized with the operation of the plasma torches, which automatically monitor the profile and internal structures of the nuclear submarine for optimal heating and melting.

 The molten metal enters the base of the melting chamber 2 and flows into the storage chamber 3, where it is additionally carbonized by the supply of powdered carbon using injectors 10 to reduce the temperature-liquidus of the melt. On the electromagnetic drain chute 14, the metal merges into the molds 17 located in the transport tunnel 16 and automatically fed under the drain chute.

 In the process of melting the radioactive part of the PO, the necessary additives are added to the melt through the supply device 9, which purify the metal from radionuclides by converting them to slag. Radioactive slag through a drain chute 15 is poured into molds (special containers), which are delivered to the storage location.

Practical implementation of the proposed technical solution will allow:
- sharply reduce the complexity and duration of nuclear submarine dismantlement (with the existing technology, incomplete nuclear submarine dismantlement is 1 year, while using the new technology it takes 10-20 days);
- localize harmful and radiation-hazardous emissions by creating reliable protective engineering structures that virtually eliminate environmental pollution;
- to exclude long-term storage of energy compartments and at the same time special expensive constructions;
- use metal in the national economy not after 100 years, but immediately after supply from the transport tunnel;
- dispose of various weapons: tanks, ships in the form of large sections, etc.

Claims (4)

1. The method of disposal of nuclear submarines, which carry out the decontamination of equipment, the removal of non-metallic materials by gasification, remelting of metal in the presence of slag additives, followed by separation of the resulting radioactively contaminated slag from molten metal, casting of metal and slag, characterized in that before deactivation equipment unload the reactor core, filters I and II circuits, radioactive water, weapons, and after decontamination - dismantle the equipment tions, arrangements and devices, then housing nuclear submarine is fed into an underground tunnel into the receiving chamber in which produce removal of nonmetallic materials, heating the body up to 500 ^o C, after which the body is heated to 700 ^o C and is transferred as it is melting in the melting chamber located in the underground tunnel behind the receiving chamber, until complete melting, while the surface of the molten metal in the storage chamber located in the lower part of the tunnel is injected with powdered carbon.  2. A complex for the disposal of nuclear submarines, comprising a melting device, a device for casting molten metal, and a gas neutralization and purification device, characterized in that it is made in the form of two underground inclined tunnels: the first, the melting, the second and the transport, tunnel, in the first tunnel the receiving, melting and storage chambers are sequentially placed, the storage chamber being located in the lower part of the first tunnel, the heating device is placed in the receiving chamber, and the device The melting point is in the melting chamber, the device for casting metal is made in the form of a drain chute, which is connected to the collecting chamber, molds for receiving metal are placed in the transport tunnel, injectors for feeding powdered carbon to the surface of the molten metal are located in the lower part of the melting chamber, and for slag collection containers are provided.  3. The complex according to claim 2, characterized in that fuel-oxygen burners located on the inner surface of the receiving chamber are used as heating elements of the heating device, and jet plasmatrons located on the inner surface of the melting chamber are used as heating elements of the melting device.  4. The complex according to claim 2, characterized in that carbon blocks are used as the working layer of the lining of the storage chamber.

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