RU2568433C1 - Underwater nuclear thermoelectric plant - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: underwater nuclear thermoelectric plant is offered which contains the light-water reactor and thermoelectric blocks (TEB) located in the gas-tight protective shell and uniformly arranged around the light-water reactor and consisting of the housing with the thermoelectric modules placed inside, while the housing in the lower and upper parts has cooling water inlet and outlet branch pipes, and the nuclear reactor housing is connected by the heat carrier pressure and discharge manifolds to the heat carrier distribution and collection manifolds of the thermoelectric modules. The gas-tight protective shell can be designed as spherical and composite, and the thermoelectric modules are implemented in the form of Fild's tube.

EFFECT: reduction of thermal losses, decrease of temperature differences of structural elements, avoidance of sea water corrosive attack of the reactor housing, creation of additional barrier for localization of emergencies.

6 dwg

Description

The invention relates to the field of power engineering, in particular to nuclear thermoelectric installations.

Installations in which the conversion of heat to electricity occurs, bypassing such intermediate stages as the conversion of heat into kinetic energy of the flow of the working fluid and the kinetic energy of the flow of the working fluid into the kinetic energy of rotation of the turbine rotor and the associated rotor of the generator, are called direct conversion of heat to electricity .

Known nuclear thermoelectric installations (YATEU), considered classical (Sarkisov A.A., Yakimov V.A., Kaplar E.P. Thermoelectric generators with nuclear heat sources. / Ed. By A.A. Sarkisov. M.: Energoatomizdat, 1987. 208 p., P. 37), when the heat source (reactor) and thermoelectric blocks (BFC) are independent units of equipment. Heat transfer in such an installation from the reactor to the BFC and from the BFC to the sea water is carried out by the coolant (pressurized water).

Nuclear power plants according to this scheme are presented in US patent No. 31118818, class 176-39, published 01/21/1964. Significant disadvantages of the presented arrangement include the placement of the reactor in sea water. Moreover, if the lower part of the reactor vessel has thermal insulation, which contacts the seawater of the non-flowing part of biological protection, then the upper part of the vessel with the reactor cover is washed with running sea water. Thus, along with significant heat losses bypassing thermocouples, the design of the reactor is subject to temperature extremes and active environmental corrosion. In addition, the upper part of the reactor structure has a significant temperature gradient with a high stress concentration coefficient due to the presence of holes and fasteners. The need to ensure heat transfer through the wall of the reactor vessel to the thermocouples leads to the fact that the thermogenerator becomes an integral part of the design of the reactor, that is, to complicate the design of the reactor itself. The large linear dimensions of the surface of the hot junction determine the high requirements for the geometric placement of thermocouples (in the patent: "20,000 individual thermoelectric elements").

Known layout of an underwater thermoelectric reactor installation (K.H. Dufrane. An underwater thermoelectric reactor plant. J. Aircraft Vol. 3, No. 4, p. 376-384) firm Martin Co. The principle approach to the layout of the installation is similar to the layout according to US patent No. 31118818. However, there are various approaches to the design of components: a reactor, a thermoelectric generator, and a circulation circuit, through which the energy of nuclear fuel is supplied to hot junctions.

Martin Co's layout includes a reactor and flat sections of thermoelectric elements connected by a piping system. The entire circuit is located in sea water, and therefore part of the heat generated in the reactor “heats” the environment and the circuit is susceptible to corrosion. The location of thermoelectric elements is located at a distance from the reactor core, sufficient to reduce the influence of neutron and γ-radiation to acceptable values.

The disadvantages of this arrangement include the branched layout of the coolant supply pipelines from the reactor to thermocouples that are washed with sea water, as well as the absence of a formed cooling circuit coolant, since the circulation occurs in the infinite half-space of sea water.

Known YaTEU "Gamma" (Buinitsky B.A. et al. Generalization of operating experience of the research nuclear thermoelectric installation "Gamma". / 12 International annual scientific and technical conference of the Russian Nuclear Society "Research Reactors: Science and High Technologies", Dimitrovgrad, 25- June 29, 2001. T. 2. Research reactors - present and future, Part 1. Dimitrovgrad. 2002, pp. 174-188. Experimental nuclear thermoelectric plant "Gamma" - prototype of the NNPPP. Atomic energy. 1993, 74, No. 1, p. 28-34). The Gamma nuclear thermoelectric installation contains a nuclear reactor and thermoelectric generating modules, the heat flux for which is formed by the temperature difference between the hot reactor coolant and the cold carrier - the pool water in which the installation is located. The primary coolant flows through the collectors to groups of thermoelectric generating modules located around the reactor vessel.

The layout of this installation also does not have a formed circulation loop of the cooling fluid, since natural circulation occurs in the half-space of the pool water. The peculiarity of using natural circulation in this installation is that the spatial temperature gradient that arises around thermocouples due to unlimited radial space creates less Archimedean force in comparison with the placement of thermocouples in space of limited sizes.

Also known are:

Patent RU 2151083 op. 06/20/2000 "Power plant of a nuclear ship." The power plant of a nuclear ship, mainly a nuclear submarine, contains a water-water reactor type and electric power sources, including turbine generators, an emergency diesel generator and / or a battery, a thermoelectric generator located in an airtight container outside the durable submarine hull in fillable with overboard water in the volumes of a light body or inside a strong body, while the thermoelectric generator has two closed heat transfer circuits with working with freezing fluid as a heat carrier, the first circuit supplying heat to the "hot" junctions of the thermoelectric generator includes a heat exchanger connected to the first circuit of the reactor installation, and the second, which removes heat from the "cold" junctions of the thermoelectric generator, includes a heat exchanger installed on the overboard water main, the heat exchanger of the first circuit of the thermoelectric generator is located in the protective shell of the reactor installation. This technical solution is not intended to work as the only source of energy located under water at ambient pressure, contains two intermediate circuits with heat exchangers, which leads to additional heat loss.

Also known patent SU 1811635, publ. 04/23/1993 - nuclear heat supply station, in which the heat exchangers of the first or second circuit are made in the form of a thermoelectric generator located in a protective housing. This device is also not intended to operate as the only source of energy located under water at ambient pressure.

The aim of the invention is to develop the design of the installation, capable of operating in a submerged position at excessive ambient pressures, with the formation of circulation paths of the primary coolant and cooling sea water without intermediate heat exchangers, with the presence of two strong walls - a gas-tight shell and a BFC housing, and the installation of the installation in a single durable shell, which will reduce heat loss, reduce temperature differences of structural elements, eliminate the corrosive effects of marine water on the reactor shell, to provide an additional barrier for containment consequences of accidents.

The applicant is not aware of technical solutions - the "underwater nuclear thermoelectric installation", designed to operate as the only source of energy located under water at ambient pressure.

An underwater nuclear thermoelectric installation is proposed that contains a light-water nuclear reactor and thermoelectric blocks (BFC) located in a gas-tight protective shell uniformly located around the reactor and consisting of a housing with thermoelectric modules placed in it, while the housing in the lower part has cooling water inlet pipes and the upper part has a cooling water outlet pipe outside the nuclear thermoelectric installation, and the nuclear reactor casing is connected to pressure and discharge collectors and coolant reservoirs with the distribution and collection of coolant thermoelectric modules.

The general layout of nuclear power plants is shown in figure 1.

In figures 2-4 shows the design of the BFC, evenly spaced around the reactor.

Figures 5 and 6 show the lower and upper mounting blocks, which, after assembly, form a nuclear power unit.

The positions in the figures are indicated as follows:

1 - reactor

2 - BTE,

3 - actuators CPS,

4 - metal protection tank,

5 - pressure header of the coolant of the primary reactor loop,

6 - drain collector of the coolant of the primary circuit of the reactor,

7 - collectors distribution of the coolant of the primary reactor loop into thermoelectric modules,

8 - collectors for collecting the coolant of the primary reactor loop from thermoelectric modules,

9 - "traction" section of the cooling circuit,

10 - electrical connectors,

11 - part of the protective gas tight shell as an element of the installation block of the installation,

12 - part of the protective gas-tight shell with a cooling circuit,

13 - thermoelectric module,

14 - strong housing BTE,

15 - pipe inlet of cooling water,

16 - pipe outlet cooling water.

The underwater nuclear thermoelectric installation contains a set of equipment and systems for nuclear power plants, including reactor 1, BTE 2, a control and protection system for the reactor (working bodies of the ship control system) 3, a set of systems that ensure the operation of nuclear power plants in normal and emergency operation, nuclear and radiation safety (at figures not shown), including metal protection tank 4, and placed in a gas tight protective shell with the temperature and pressure of the gaseous medium inside it, characteristic of ground nuclear installations.

The gas tight containment consists of at least two parts 11 and 12, which allow installation to be carried out in a limited space. The dimensions of the gas tight containment are limited by the real capabilities of the metallurgical industry and the properties of materials.

The design of the BFC 2, evenly spaced around the reactor, is shown in figures 2-4. The BFC contains a group of ring thermoelectric modules 13 located in a durable BFC housing 14. The durable BFC housing in the upper and lower parts has cooling water inlet pipes 15 and cooling water outlet pipe 16.

The primary coolant from the reactor 1 through the pressure header 5 enters the distribution manifold into thermoelectric modules 7. The coolant cooled in the thermoelectric modules 13 passes through the collector from the thermoelectric modules 8 to the drain manifold 6 and from there again to the reactor 1.

Cooling water through the cooling water inlet pipes 15 enters the BTE 14 robust housing and, being heated from the thermoelectric modules 13, enters the cooling water outlet pipe 16, after which it is discharged outside the nuclear power plant through the traction section 9.

In thermoelectric modules 13 organized circulation type - Field tube.

The circulation circuit of the primary coolant is made in such a way that the flow cross-section along the circuit allows the coolant to flow at a speed close to a constant value, and the placement of thermoelectric modules 13 in the robust housing of BTE 14 ensures uniform heat flow due to uniform flow around seawater.

The natural circulation along the primary circuit and the cooling water circuit has been implemented.

Spatial-dense layout leads to the need to take into account the subsequent installation of the installation. In this regard, the installation is formed of two mounting blocks: the lower mounting block (shown in figure 5) and the upper mounting block (shown in figure 6), which after their assembly form a nuclear power unit.

A feature of the proposed installation is the design of the circulation circuit of the primary coolant and its placement in a protective shell. This arrangement significantly improved the operating conditions of nuclear power plants compared with their analogues - reduced heat losses, reduced temperature differences of structural elements, eliminated the corrosive effects of sea water on the reactor vessel, created an additional barrier to localize the consequences of emergency situations.

The subcriticality inherent in the design of the reactor core allows the control rods to be completely removed from the core at the time of start-up and held in this position for the entire service life. Upon reaching the nominal position of the rods, the basic principle of nuclear regulation is provided, which stabilizes the temperature of the core regardless of energy consumption. In the proposed installation, the effects of compensation for fuel burnup are compensated for by using burnable absorber rods (based on gadolinium) in the fuel assemblies, which ensures the preservation of a uniform design temperature throughout the entire core campaign, which, in turn, helps to maintain a given temperature difference between the circuits and, as a result, the most efficient operation of thermoelectric modules during the entire project campaign.

Operating modes

For reliable heat removal from the primary circuit, the commissioning of a nuclear power plant is allowed only when the object (self-propelled or towed) from the nuclear power plant is completely immersed in cooling (sea) water.

Controlled start-up of the reactor is possible with remote or automatic control. A signal of the reverse period of doubling the power of the reactor (for a given value of the period of 30 s) is proposed as a control signal. This is most preferred for reasons of safety and robustness of automatic control. The power of the end of the start (start of heating) can be adopted 0.1 ... 0.5% N _nom . In this case, it is assumed to use signals from the ionization chambers of the external (relative to the reactor or installation) location.

The heating of the reactor is carried out with automatic control. As the main control signal, the deviation of the coolant temperature from the specified program scan is accepted (it is also possible to use the signal of the deviation of the heating rate from the set). Acceptable accuracy of maintenance can be in the range of 3 ... 5 ° C in temperature. To increase the stability of regulation as a corrective, it is advisable to use a signal of the inverse period. Protection of the installation in the start-up and warm-up modes is carried out by the signal of the period of power doubling.

During normal operation, the nuclear power plant operates at a near-nominal level of thermal power (100% N _nom - 7.5 MW) with the delivery of electric power to the consumer. Electric power varies from 0 to 100% N _elec. due to the connection-disconnection of thermoelectric blocks to the electrical load. In the process of operation of the nuclear power plant, the maintenance of the set values of the installation parameters is provided by controlling the temperature at the outlet of the reactor core.

A planned or emergency decommissioning of the installation can be carried out by resetting the emergency protection (compensating groups), followed by self-cooling of the installation on natural circulation. In this case, the rate of reduction of the outlet temperature will be about 30 ... 50 ° C / min.

Thus, the invention will allow the creation of a nuclear thermoelectric installation to provide energy to an underwater technical consumer, the first circuit of which has an additional protective barrier and does not have direct contact with a corrosive marine environment, while ensuring the compactness of the installation, which is important for underwater installations. In addition, the installation provides localization of accidents and reduce heat loss.

Claims (1)

An underwater nuclear thermoelectric installation containing a light-water nuclear reactor and thermoelectric blocks (BFCs) located in a gas-tight protective shell, uniformly located around the reactor and consisting of a housing with thermoelectric modules placed in it, the housing in the lower part having cooling water inlets and in the upper of the part has a cooling water outlet pipe outside the nuclear thermoelectric installation, and the nuclear reactor casing is connected by pressure and discharge heat collectors of Tell with collectors delivering and collecting the coolant thermoelectric modules.

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