RU2804924C1 - Double-circuit nuclear power plant for nuclear-powered ships - Google Patents

Abstract

FIELD: nuclear power plants.

SUBSTANCE: invention relates to a nuclear power plant for nuclear-powered ships. The installation consists of nuclear reactor 2, liquid circuit 3 with diathermic oil as a working fluid and steam circuit 5 with pentane as a working fluid, located inside the hull of nuclear-powered ship 1. In nuclear reactor 2, thermal energy is generated, which is converted through liquid circuit 3 and steam circuit 5 into a high pressure of pentane vapor, which is activated in steam turbine 7, in which, due to the rotation of turbine 7, the rotation of electric generator 8 is ensured and the generation of useful electrical energy for propulsion electric motors 14 and other power consumers 15 of the nuclear-powered ship connected to electric generator 8. If it is necessary to sharply dump the load and reduce the power of turbine 7, followed by repeated acceleration, the steam generated by steam generator 6 is discharged using bypass line 11 directly from steam cavity 20 of steam generator 6 into steam cavity 22 of condenser 9, bypassing turbine 7. Regulation of the reduction or increase in power of turbine 7 is ensured by the degree of “closing-opening” of control valve 24 and pickling control valve 12.

EFFECT: increasing the energy efficiency and reliability of the operation of a nuclear power plant, as well as increasing the efficiency of regulation during shunting operating modes of a steam turbine of a nuclear power plant.

1 cl, 1 dwg

Description

The invention relates to the field of ship nuclear power and can be used in the construction of nuclear icebreakers, nuclear submarines, civilian ships and warships with nuclear power plants, floating nuclear thermal power plants (FNPP), etc.

It is known to design underwater nuclear thermal power plants for uninterrupted power supply of mining technological complexes in fields in ice-hazardous zones of the Arctic and/or Far Eastern seas, based on the use of experience accumulated in underwater shipbuilding and Arctic under-ice voyages of nuclear submarines (RF Patent No. 2399104, publ. from 09/10/2010, Bulletin No. 25).

It is known that in nuclear power plants with double-circuit water-cooled reactors of the VVER type, which include an interconnected reactor, liquid and steam circuits, while the working fluid of the liquid circuit passes through the reactor and is intended for reliable and constant cooling of the core reactor, high-pressure water is used, and the working fluid of the steam circuit is water and steam produced by the heat generated in the reactor and used in a steam turbine to produce electricity (RF Patent No. 2742730, published on 02/10/2021, Bull. No. 4).

A disadvantage of water-cooled nuclear reactors of the VVER type (reactors with pressurized water) is the operation of the steam circuit (steam-producing plant) when the liquid circuit coolant in the form of high-pressure water is pumped through its steam generators, which imposes special requirements on the design and operation of the liquid circuit for the operation of vessels under pressure. high pressure.

It is known that the main disadvantage of nuclear power plants based on pressurized water reactors (pressurized water reactors) with steam turbine units is the low steam parameters of the steam circuit at the outlet of the steam generators: pressure about 3.0-3.7 MPa and temperature 285- 300°C, which is caused by limiting the temperature of the coolant of the liquid circuit - water to maintain it in the liquid phase. As a result, the efficiency of such installations is about 20%. Due to the low initial steam parameters of the steam circuit, the flow part of the steam turbine operates in the wet steam region. In addition to the low cycle efficiency, at low initial steam parameters, due to high humidity, the internal efficiency decreases and intense drop-impact erosion of turbine unit blades occurs (RF Patent No. 2757737, published on October 21, 2021, Bulletin No. 30).

To eliminate these disadvantages, it is necessary to use intermediate separation and intermediate superheating of steam, which leads to a significant complication of the design of nuclear power plants based on pressurized water reactors and requires the use of additional volumetric equipment.

There is a known method of operating a nuclear reactor with an organic coolant of the ARBUS installation (Arctic block plant), which involves organizing the pumping of an organic working fluid (coolant) in a closed loop through the core of a nuclear reactor, bringing the reactor to power and operating at power with removal of the generated energy by a closed-loop coolant (Aleksenko Yu.N., Gavrilin A.I., Gataullin N.G. and others. Experience in operating the ARBUS reactor plant. // Collection of reports of the seminar “Prospects for the use of nuclear reactors for heat supply of cities and industrial enterprises.” Dimitrovgrad, RIAR , 1978, pp. 24-44). Organic working fluids include liquids containing carbon in their structure. Various types of organic liquids, for example, hydrostabilized gas oil, hydroterfinyl, etc., can be used as an organic working fluid (coolant) in a closed reactor circuit.

The use of organic liquids as coolants in nuclear reactors is based on the fact that these liquids have a number of advantages compared to other types of coolants. In particular:

- low coolant activation allows servicing the coolant circuit even during reactor operation;

- the high boiling point of the organic coolant at atmospheric pressure makes it possible to avoid its boiling in the event of an accidental loss of pressure in the circuit;

- low operating pressure in a closed liquid circuit of a nuclear power plant significantly reduces the likelihood of rupture of equipment and pipelines;

- the corrosive passivity of the coolant to structural materials allows the use of cheap aluminum alloys and carbon steels as the latter, and the use of serial oil equipment and fittings as part of the primary circuit without imposing special requirements on them;

- the comparative simplicity of maintenance, repair and control of the reactor makes it possible to automate the installation as much as possible, reduce the requirements for the qualifications of operating personnel and limit their number.

All together, this provides unique opportunities to ensure nuclear and radiation safety, ease of operation and reduction of capital costs for construction, which is especially attractive when used in remote areas.

There is a known method of operating a nuclear reactor with an organic working fluid (coolant) of the ATU-15×2 power plant, which involves cooling the reactor core by circulating the organic coolant (ditolylmethane) in a closed loop (Tokarev Yu.I., Tsykanov V.A., Ryumin V.P. et al. ATU-15×2 - nuclear heat supply station for remote areas. // Questions of atomic science and technology. Ser. Physics and technology of nuclear reactors. 1978. Issue 1/21, part 1, p. 112 -116).

The disadvantage of this technical solution is the use of ditolylmethane as an organic coolant in a closed loop reactor, whose molecules under the influence of prolonged ionizing radiation and temperature can disintegrate, forming light, medium and heavy fractions. The latter, interacting with each other, form super-heavy molecules that are deposited on heat transfer surfaces in the form of deposits (fowling effect), which leads to deterioration in the cooling of fuel rods, their cleaning and requires replacement of the coolant.

It is known that in recent years new types of organic liquids have appeared in operation - diathermic oils (heat-transfer oils), which are conventional petroleum distillate oils of selective purification - this is a product of deep oil refining followed by distillation, which have low corrosiveness and the ability to cause the formation of various deposits inside the circulation system. Currently, both Russian and imported diathermic oils (heat-transfer oils) are presented on the domestic market, for example, LUKOIL TERMO OIL, Mobiltherm, ShellHeatTransferoilS2, Bashneft AMT-300, Gazpromneft MT-300, etc. Temperature range of use of various diathermic oils as coolants vary from -115°C to 410°C. Heat-transfer oils are used in closed circulation systems (V.I. Stakhiv. Review and comparative characteristics of heat-transfer oils used in Russia / V.I. Stakhiv, L.N. Bagdasarov, V.I. Stakhiv // Young scientist. - 2016 - No. 2 (106). - P. 73-76).

The use of an organic liquid - diathermic oil as a coolant (working fluid) for supplying thermal energy in various technological processes in industry is preferable to steam heating, as it allows one to obtain high temperatures at low pressures, which reduces the cost of basic equipment. Due to the high flexibility of such systems, many industrial technologies developed in the last decade (production of polyester resins, synthetic resins, thermoplastic materials, etc.) use oil at temperatures up to 340°C.

A known energy system is a closed steam circuit with an organic working fluid containing a turbine on a shaft with an electric generator and a cooling system with a heat exchanger and a circulation pump, while the system is equipped with a source of thermal energy for heating the working fluid of the steam circuit for combustion of associated gas (RF Patent No. 2573541, published on January 20, 2016, Bulletin No. 2).

However, this technical solution cannot be applied when using a nuclear reactor as a source of thermal energy.

The device of a steam condenser is known, used on ships and vessels with a nuclear power plant and consisting of a housing (tank), in the upper part of which there is a steam cavity with an inlet pipe for waste steam, and in the lower part there is a liquid cavity in the form of a condensate collector, while inside In the housing of the steam condenser, a heat exchanger is installed to pump a cooling medium through it, for example, sea water (RF Patent No. 2697073, published on August 12, 2019, Bulletin No. 23).

There is a known method for controlling a nuclear power plant, which consists in monitoring changes in the external load by a turbine control system using a control valve that changes the steam flow to the turbine based on a signal to maintain the turbine speed, and regulating the steam pressure by changing the position of the steam generator feedwater valve based on a signal that the steam pressure deviates from given value (Yurkevich G.P. "Control systems for nuclear reactors. Principles of operation and creation", M., 2009, p. 331, Fig. 5.12).

A double-circuit nuclear power plant for nuclear-powered ships is known, consisting of a pressurized water nuclear reactor located inside the hull of a nuclear-powered ship and two closed circuits, the first of which is a liquid circuit containing a heat exchanger and a circulation pump, and the second is a steam circuit, including a steam generator, a steam shunting a turbine with an electric generator on the same shaft, a condenser and a liquid pump, wherein the liquid circuit passes through the nuclear reactor and the steam generator of the steam circuit, the electric generator is connected to the propeller electric motors and other electrical consumers of the nuclear-powered ship, and the steam circuit is equipped with a bypass line for maneuvering the turbine, containing a pickling control valve and throttle device and connecting the section of the steam circuit between the steam generator and the turbine with the steam circuit condenser (Energy of nuclear ships / A.N. Dyadik, S.N. Surin. - St. Petersburg: Shipbuilding, 2014. - 477 p.: ill., p. 165 -170).

The main disadvantages of this technical solution is the use of water as working fluids in the liquid and steam circuits of a nuclear power plant and, as a consequence, the need to create high water pressure in the liquid circuit, which removes heat from the reactor core, to prevent water vaporization in the reactor core, which leads to to an increase in the weight and size characteristics of the nuclear reactor and liquid circuit pipelines and an increase in the likelihood of destruction of the liquid circuit pipelines, while the use of water in the steam circuit leads to intense corrosion of steam turbine blades and low efficiency due to low steam pressure at the outlet of the steam generator, as well as low efficiency regulation (maneuvering) of the operation of the steam turbine due to the inertia of the turbine operation due to the possibility of regulating the steam supply only by the pickling control valve of the bypass line connecting the section of the steam circuit between the steam generator and the turbine with the steam circuit condenser, which does not ensure a rapid reduction in steam flow through the turbine.

The technical result that can be obtained by implementing the invention is to increase the energy efficiency of a nuclear power plant, increase the reliability of operation and reduce the weight and size characteristics of the nuclear reactor and the pipelines of the liquid circuit of the power plant, increase the reliability of operation and reduce the accident rate of the steam turbine, as well as increase the efficiency of regulation during shunting operating modes of a steam turbine of a nuclear power plant.

To achieve this technical result, the proposed double-circuit nuclear power plant for nuclear-powered ships, consisting of a nuclear reactor located inside the hull of a nuclear-powered ship and two closed circuits, the first of which is a liquid circuit containing a heat exchanger and a circulation pump, and the second, a steam circuit including a steam generator, a shunting steam turbine with an electric generator on the same shaft, a condenser and a liquid pump, wherein the liquid circuit passes through the nuclear reactor and the steam generator of the steam circuit, the electric generator is connected to the propeller electric motors and other electrical consumers of the nuclear-powered ship, and the steam circuit is equipped with a bypass line for maneuvering the turbine containing a control valve etching and throttling device and providing steam supply to the steam circuit condenser bypassing the steam turbine, characterized in that it is equipped as working fluids of the liquid and steam circuits with organic working fluids, a steam generator and a steam circuit condenser, made in the form of containers divided into steam and liquid cavities , a closed cooling circuit with a circulation pump containing a heat exchanger-cooler located in the steam cavity of the condenser, and a thermal energy discharge heat exchanger through which the sea cold water line passes with the circulation pump, while the bypass line connects the steam cavities of the steam generator and the condenser, and between the steam generator and the turbine is equipped with a control valve for the steam circuit.

An organic working fluid in the form of diathermic oil is used as the working fluid of the liquid circuit.

An organic working fluid in the form of pentane is used as the working fluid of the steam circuit.

Introduction into the composition of a double-circuit nuclear power plant for nuclear powered ships of organic working fluids as working fluids of the liquid and steam circuits, a steam generator and a steam circuit condenser, made in the form of containers divided into steam and liquid cavities, a closed cooling circuit with a circulation pump containing a heat exchanger-cooler , located in the steam cavity of the condenser, and a heat exchanger for releasing thermal energy, through which a line of sea cold water passes with a circulation pump, while the bypass line connects the steam cavities of the steam generator and condenser, and a control valve is installed on the steam circuit between the steam generator and the turbine, allowing to obtain a new a property that consists in the possibility of increasing the energy efficiency of a nuclear power plant by increasing the temperature of the working fluid of the liquid circuit without vaporization of the working fluid in the reactor core, and, accordingly, increasing the temperature and pressure of steam in the steam circuit when it leaves the steam generator due to replacement of the working fluid liquid circuit from the use of water to the use of an organic working fluid in the form of an organic liquid of diathermic oil, and replacing the working fluid of a steam circuit from the use of water to the use of an organic working fluid of pentane, increasing operational reliability and reducing the weight and size characteristics of a nuclear reactor and pipelines of the liquid circuit of a power plant due to reducing pressure in a nuclear reactor and the liquid circuit of a power plant due to the use of an organic working fluid in the form of diathermic oil as a working fluid, as well as increasing the reliability of operation and reducing the accident rate of a steam turbine due to the use of an organic working fluid in the steam circuit of a nuclear power plant ( pentane) instead of water, which eliminates the operation of the steam turbine flow path in the area of wet steam and leads to a decrease in corrosion of steam turbine blades, as well as an increase in the efficiency of regulation during shunting operating modes of a steam turbine of a nuclear power plant due to the combined and simultaneous use of the “opening-closing” process » a control valve on the steam circuit, installed between the steam generator and the turbine, and a control valve for the pickling of the bypass line, directly connecting the steam cavities of the steam generator and the condenser of the steam circuit, bypassing the steam turbine.

In fig. 1 shows a schematic diagram of a double-circuit nuclear power plant for nuclear-powered ships, where:

1 - hull of a nuclear-powered ship (nuclear-powered icebreaker, nuclear-powered submarine, civilian ship or warship with a nuclear power plant);

2 - nuclear reactor;

3 - liquid circuit;

4 - liquid circuit circulation pump;

5 - steam circuit;

6 - steam generator;

7 - steam turbine;

8 - electric generator;

9 - steam circuit condenser;

10- steam circuit circulation pump;

11 - bypass line for maneuvering the turbine;

12 - bypass line etching control valve;

13 - bypass line throttle device;

14 - rowing electric motors;

15 - other power consumers of the nuclear-powered ship;

16 - closed cooling circuit;

17 - heat exchanger-cooler of a closed cooling circuit;

18 - circulation pump of a closed cooling circuit;

19 - heat exchanger for discharging thermal energy of a closed cooling circuit;

20 - steam cavity of the steam generator;

21 - liquid cavity of the steam generator;

22 - steam cavity of the condenser;

23 - liquid cavity of the condenser;

24 - steam circuit control valve;

25 - sea cold water line;

26 - circulation pump of the sea cold water line;

27 - liquid circuit heat exchanger.

The proposed double-circuit nuclear power plant for nuclear-powered ships operates as follows.

To operate the proposed nuclear power plant for nuclear-powered ships, a double-circuit nuclear installation is used, consisting of a nuclear reactor 2, a liquid circuit 3 and a steam circuit 5, located inside the hull of the nuclear-powered ship 1.

In nuclear reactor 2, due to the fission reaction of nuclear fuel, thermal energy is released and transferred to the organic working fluid in the form of diathermic oil in liquid circuit 3, which leads to heating of the diathermic oil to a high temperature. The circulation of the organic working fluid of the liquid circuit 3 is ensured by the operation of the circulation pump 4. In this case, the organic working fluid - diathermic oil of circuit 3 does not change its state of aggregation during circulation through circuit 3 and constantly remains in a liquid state.

The diathermic oil of circuit 3, heated to a high temperature, transfers thermal energy to the organic working fluid (in the form of pentane) of the steam circuit 5 in the steam generator 6 through the heat exchanger 27 of the liquid circuit 3. After heat transfer, the cooled diathermic oil of circuit 3 from the heat exchanger 27 again enters the nuclear reactor 2 with using a circulation pump 4.

When transferring thermal energy in the steam generator 6, the organic working fluid of the steam circuit 5 (pentane), due to thermal energy, is initially heated in the liquid cavity 21 of the steam generator 6, turns into steam and then is overheated in the steam cavity 20 of the steam generator 6 to high temperature and pressure.

From the steam cavity 20 of the steam generator 6 of the steam circuit 5, superheated steam of the organic working fluid (pentane) under high pressure through an open control valve 24 enters the steam turbine 7 with an electric generator 8 on the same shaft. In this case, the pickling control valve 12 of the bypass line 11 is closed.

The high pressure of pentane vapor is activated in the steam turbine 7, in which, due to the rotation of the turbine 7, the rotation of the electric generator 8 is ensured and useful electrical energy is generated for the propulsion electric motors 14 and other electrical consumers 15 of the nuclear-powered ship connected to the electric generator 8.

It should be noted that the use of an organic working fluid - pentane - as the working fluid of circuit 5, makes it possible to reduce the weight and size characteristics of the steam turbine 7 and reduce the corrosion of the blades of the steam turbine 7.

In this case, the energy efficiency of the nuclear power plant increases due to an increase in the temperature of the working fluid of the liquid circuit 3 to 400°C without vaporization of diathermic oil in the reactor core, and, accordingly, an increase in the temperature and pressure of pentane vapor in the steam circuit 5 when it exits steam generator 6 and the inlet to the steam turbine 7.

Passing the steam turbine 7, vapors of the organic working fluid reduce pressure and enter the gas cavity 22 of the condenser 9 of the steam circuit 5, where they are condensed due to cooling during heat exchange with the cooling medium passing through the heat exchanger-cooler 17 of the closed cooling circuit 16, while the heat exchanger-cooler 17 is placed in the gas cavity 22 of the capacitor 9.

The condensed pentane vapor flows into the liquid cavity 23 of the condenser 9. Then, from the liquid cavity 23 of the condenser 9, the condensed pentane vapor is supplied to the liquid cavity 21 of the steam generator 6 using a circulation pump 10.

If there is a need for a sharp load shedding and the need to reduce the power of turbine 7, which occurs when a nuclear-powered ship (for example, a nuclear-powered icebreaker or a warship with a nuclear power plant) is completely stopped or slowed down in heavy ice or other maneuvers, and then the need for subsequent re-acceleration, excess The steam generated by the steam generator 6 was discharged using the bypass line 11 directly from the steam cavity 20 of the steam generator 6 into the steam cavity 22 of the condenser 9, bypassing the turbine 7. This ensures maneuvering of the turbine 7 by opening the pickling control valve 12 and passing the steam through the bypass throttle device 13 line 11 directly from the steam cavity 20 of the steam generator 6 to the steam cavity 22 of the condenser 9, bypassing the turbine 7, as well as by closing the control valve 24 on the steam circuit 5 installed between the steam generator 6 and the turbine 7. Regulation of the decrease or increase in power of the turbine 7 is ensured by the degree of “closure” - opening the control valve 24 and the pickling control valve 12.

The above-described process makes it possible to significantly increase the efficiency of regulation during shunting operating modes of the steam turbine 7 of a nuclear power plant due to the combined and simultaneous use, on the one hand, of the “opening-closing” process of the control valve 24 on the steam circuit 5, installed between the steam generator 6 and the turbine 7, and the pickling control valve 12 of the bypass line 11, and on the other hand, directly connecting the steam cavity 20 of the steam generator 6 and the steam cavity 22 of the condenser 9 of the steam circuit 5, bypassing the steam turbine 7.

As noted above, for cooling and condensation of pentane vapor (organic working fluid) of the steam circuit 5, a heat exchanger-cooler 17 of a closed cooling circuit 16 is placed in the gas cavity 22 of the condenser 9, through which a cooling medium (for example, water) circulates using a closed circulation pump 18 cooling circuit 16. During heat exchange through the walls of the heat exchanger-cooler 17, pentane vapor condenses, and the cooling medium heats up.

The heated cooling medium of the closed cooling circuit 16, using a circulation pump 18, is supplied to the thermal energy discharge heat exchanger 19 of the closed cooling circuit 16, where the heated cooling medium is cooled to the temperature of the sea water due to heat exchange with the sea cold water supplied through the sea cold water line 25 using circulation pump 26.

Then, the cooling medium of the closed cooling circuit 16, cooled to the temperature of the ambient cold water, is again supplied to the gas cavity 22 of the condenser 9 using the circulation pump 18 for heat exchange, cooling and condensation of vapors of the organic working fluid (pentane) of the steam circuit 5.

In this case, the cooling circuit 16 is closed, which makes it possible to create a closed cooling circuit 16 to ensure cooling and operation of the steam circuit, as well as the generation of useful electrical energy for the propulsion motors 14 and other electrical consumers 15 of the nuclear-powered ship.

Sources of information taken into account when preparing the application:

1. RF Patent No. 2399104, publ. dated 10.09.2010, Bulletin. No. 25.

2. RF Patent No. 2742730, publ. dated 02/10/2021, Bulletin. No. 4.

3. RF Patent No. 2757737, publ. dated 10/21/2021, Bulletin. No. 30.

4. Aleksenko Yu.N., Gavrilin A.I., Gataullin N.G. and others. Experience in operating the ARBUS reactor plant.// Coll. report seminar “Prospects for the use of nuclear reactors for heat supply to cities and industrial enterprises.” Dimitrovgrad, RIAR, 1978, p. 24-44

5. Tokarev Yu.I., Tsykanov V.A., Ryumin V.P. etc. ATU-15×2 - nuclear heat supply station for remote areas. // Issues of atomic science and technology. Ser. Physics and technology of nuclear reactors. 1978. Vol. 1/21, part 1, pp. 112-116.

6. Stakhiv V.I. Review and comparative characteristics of heat transfer oils used in Russia / V.I. Stakhiv, L.N. Bagdasarov, V.I. Stakhiv // Young scientist. - 2016. - No. 2 (106). - pp. 73-76.

7. RF Patent No. 2573541, publ. dated January 20, 2016, Bulletin. No. 2.

8. RF Patent No. 2697073, publ. dated 08/12/2019, Bulletin. No. 23.

9. Yurkevich T.P. "Nuclear reactor control systems. Principles of operation and creation", M., 2009, p. 331, fig. 5.12.

10. Energy of nuclear ships / A.N. Dyadik, S.N. Surin. - St. Petersburg: Shipbuilding, 2014. - 477 p.: ill., pp. 165-170 - prototype.

Claims (1)

A double-circuit nuclear power plant for nuclear-powered ships, consisting of a nuclear reactor located inside the hull of a nuclear-powered ship and two closed circuits, the first of which is a liquid circuit containing a heat exchanger and a circulation pump, and the second is a steam circuit, including a steam generator, a shunting steam turbine with an electric generator on one shaft, a capacitor and a liquid pump, while the liquid circuit passes through the nuclear reactor and the steam generator of the steam circuit, the electric generator is connected to the propeller motors and other electrical consumers of the nuclear-powered ship, and the steam circuit is equipped with a bypass line for maneuvering the turbine, containing a pickling control valve and a throttling device and providing supply of steam to the condenser of the steam circuit bypassing the steam turbine, characterized in that it is equipped as a working fluid of the liquid circuit with an organic working fluid in the form of diathermic oil, as a working fluid of the primary circuit with an organic working fluid in the form of pentane, a steam generator and a steam circuit condenser, made in in the form of containers divided into steam and liquid cavities, a closed cooling circuit with a circulation pump containing a heat exchanger-cooler located in the steam cavity of the condenser, and a thermal energy discharge heat exchanger through which the sea cold water line passes with the circulation pump, while the bypass line connects steam cavities of the steam generator and condenser, and a steam circuit control valve is installed between the steam generator and the turbine.