FR3090083A1 - Emergency condenser for steam generator - Google Patents

Abstract

Emergency condenser for steam generator The invention relates to a condenser 3 SACO for steam generator 2 of a reactor, comprising: a heat exchanger comprising a shell 300, a regulation system 31 for the supply of tertiary water of the exchanger. The regulation system 31 advantageously comprises: a shutter 310 configured to regulate a tertiary water flow upstream of the inlet of the calender 300. This shutter is connected on the one hand to a float 311 configured to move the shutter in function of a tertiary water level in the calender 300, so as to regulate the flow rate in a passive mode, and on the other hand to an electromechanical device 312 configured to move said shutter independently of the tertiary water level in the calender 300, so as to regulate the flow rate in an active mode. The invention also relates to a regulation system for SACO, a nuclear power plant equipped with a SACO condenser is a method of operating a SACO condenser. Figure for the abstract: Fig. 2A

Description

Description

Title of the invention: Emergency condenser for steam generator

Technical area

The invention relates to the field of nuclear power plant safety. It relates more particularly to a radiator emergency condenser for cooling a steam generator of such a power plant. The invention finds particularly advantageous application of the backup condensers with calender for cooling a steam generator of a nuclear water reactor, and more particularly pressurized water reactors (PWR).

Prior art

A REP type nuclear reactor is illustrated in FIG. 1.

Such a reactor generally comprises a core 1 fluidly connected to a primary circuit 10 in which the pressurized water circulates.

The primary circuit 10 provides the transport of heat from the heart 1 in one or more steam generators 2. Here, only a loop of the primary circuit 10 and a single steam generator 2 are illustrated. In practice, the primary circuit 10 can comprise three or four loops on each of which is placed a steam generator 2. The simplified diagram of FIG. 1 illustrates other perfectly conventional elements of a primary circuit and of a core. reactor such as the control rods 12 and the fuel 13 present in the core 1, a hydraulic pump 11, a confinement enclosure 100.

The steam generator 2 is connected to a secondary circuit 20 in which a secondary water circulates.

Part 20a of the secondary circuit makes it possible to supply the steam generator 2 with liquid secondary water.

This liquid secondary water is transformed into secondary steam water, or secondary steam, by heat exchange between the primary and secondary circuits at the level of the steam generator 2.

Secondary steam produced by the steam generator 2 circulates in a part 20b of the secondary circuit. This secondary steam then makes it possible to drive turbines 22 for the production and transformation of electricity via alternators 50 and transformers 500.

By vaporizing, the secondary water also makes it possible to cool the primary circuit 10. The steam generator 2 is therefore a main cooling system of the reactor.

In case of loss of secondary water supply to the steam generator 2 (reference accident scenario), two alternative solutions can be implemented.

A first solution is to provide auxiliary water tanks and pumps in order to draw water from the auxiliary tanks and inject it into the secondary circuit. The water injected into the secondary circuit replaces the mass of steam lost in the steam generators. A disadvantage of this solution is that the pumps are powered by electric motors, which necessarily induces a risk of failure in the event of a major problem.

A second solution is based on the use of SACO safety condensers 3 (English acronym for "Safety Condenser"). This solution aims to cool and therefore to condense the secondary steam produced by the steam generators 2 to replenish the secondary circuit 20a with liquid secondary water.

These safety condensers 3 are themselves supplied with tertiary water by a tertiary circuit. They are usually placed high up outside the reactor building to avoid the need for lift pumps. Such SACO condensers placed at a higher height than that of the steam generator can advantageously supply the generator passively, benefiting from a flow by gravity of the secondary steam condensate.

A condenser 3 SACO comprises in particular a heat exchanger having on the one hand inputs / outputs, called secondary, connected to the secondary circuit, and on the other hand inputs / outputs, said tertiary, connected to the tertiary circuit.

This heat exchanger generally comprises at least one tube 32, a secondary inlet of which receives the secondary steam, is connected to the part 20b of the steam generator 2 and of which a secondary outlet, through which the secondary condensate flows, is connected to part 20a of the steam generator 2.

This heat exchanger also includes an envelope in which the tubing 32 is located, and which can be at least partially filled with tertiary water from the tertiary circuit.

Two main categories of SACO 3 exist, called "SACO pool" and "SACO calender", depending on the type of envelope used.

The "pool SACO" is based on the use of an envelope enclosing a large volume of water in which the tubing 32 is completely submerged. The swimming pool SACO is configured to directly deliver the maximum dissipation of thermal power. This type of ODS therefore has the drawback of not being able to be controlled as a function of the thermal power to be dissipated.

The "SACO calender" is a system where the tubing 32 is contained in an envelope of smaller volume called calender 300.

The tertiary water supply flow rate to the radiator grille 300 can be actively controlled by a variable-flow solenoid valve, as described in document WO 9304480. This active control of the flow rate is however not completely safe. Indeed:

- in the event of a power supply fault with the solenoid valve open, all of the tertiary water in the tank is poured into the grille and therefore wasted. After a very short delay, the water is no longer available.

- in the event of a power supply fault with the solenoid valve closed, the supply of tertiary water stops and cooling of the secondary steam is no longer possible.

The tertiary water supply flow rate to the calender 300 can be controlled by a regulating member as described in document FR 2584228. This regulating member notably comprises a shutter controlled by a return spring calibrated as a function of pressurization of the radiator grille. When the hydrostatic pressure of the grille decreases, the shutter opens and actuates a cylinder of pressurized gas which expands in a tank of the tertiary circuit. Tertiary water is then injected into the shell until a nominal hydrostatic pressure is restored in the shell. The shutter closes and cuts the trigger on the cylinder. The opening or closing of this shutter is therefore subject to the hydrostatic pressure of the grille.

This flow control is however not precise. It does not effectively manage the supply of tertiary water according to the cooling generator steam need, for example for different levels of residual thermal power to be evacuated. It also requires activation by the pressurized gas cylinder. This flow control is therefore not completely safe.

An object of the present invention is to at least partially overcome these drawbacks.

In particular, an object of the present invention is to provide a safety condenser making it possible to regulate the tertiary supply flow rate with improved precision, and having an improved level of safety for regulating this flow rate.

Another object of the invention is a method of operating such a safety condenser.

The other objects, characteristics and advantages of the present invention will appear on examining the following description and the accompanying drawings. It is understood that other advantages can be incorporated. In particular, certain characteristics and advantages of an aspect of the invention, such as the operating method, can be applied mutatis mutandis to another aspect of the invention, such as the condenser, and vice versa. Summary of the invention

To achieve at least one of these objectives, the present invention provides, according to a first aspect, an emergency condenser for a steam generator of a nuclear power station, said condenser comprising:

- a heat exchanger comprising:

• a radiator grille having at least one inlet, called the tertiary inlet, intended to be supplied with so-called tertiary water, and having an outlet, known as the tertiary outlet, intended for discharging so-called tertiary steam, and • at least one pipe located in the calender and intended to be at least partially submerged in tertiary water, said at least one tube having an inlet, called secondary inlet, intended to receive so-called secondary steam produced by a steam generator of the nuclear power station and having an outlet , called secondary outlet, intended to supply a so-called secondary condensate intended for the steam generator,

- - a tertiary water supply regulation system having a tertiary supply inlet configured to receive tertiary water, preferably coming from a reservoir, the regulation system being intended to regulate a tertiary water level in the grille.

The regulation system includes:

- an enclosure configured to be in fluid communication with the grille, so as to present said tertiary water level,

- a shutter intended to cooperate with said tertiary supply inlet, the shutter being movable between:

• an open position authorizing the circulation of tertiary water through said tertiary supply inlet, • a closed position preventing the circulation of tertiary water through said tertiary supply inlet, • said shutter being actuable by a first actuator said passive actuator and by a second actuator said active actuator, • the passive actuator being located in the enclosure, and configured to move the shutter between the open position and the closed position as a function of the tertiary water level in the enclosure (30), so as to regulate a tertiary water flow in a passive mode, and • the active actuating device being configured to move said shutter independently the tertiary water level in the enclosure, so as to regulate the flow in an active mode.

The regulation system for the supply of tertiary water to the SACO condenser according to the invention therefore makes it possible to regulate the flow rate in a passive mode and / or in an active mode.

The active regulation mode, controlled by the active actuation device, makes it possible to manage the supply of tertiary water as a function of the effective need for cooling of the steam generator.

Active regulation makes it possible to precisely control the supply rate of tertiary water to the ODS grille.

In this active mode, the flow can thus be regulated as a function of the effective thermal power to be removed. This power can vary depending on the state of the core during the life of the reactor, for example.

For a tertiary water level in the given enclosure, the actively controlled flow variation makes it possible to ensure constant power extraction over a wide range of secondary steam temperature values.

The passive regulation mode, controlled by the passive actuation device, makes it possible to manage the supply of tertiary water in the event of failure of the active mode for example.

In the event of a cut in the electrical supply to the active actuation device, the latter is preferably automatically disengaged and the supply of tertiary water to the CESO remains under control of the passive actuation device. The cooling of the power generator by the CESO remains effective.

Thus, the claimed SACO condenser has a considerably improved level of safety compared to existing solutions.

According to a second aspect, the invention relates to a system for regulating the supply of tertiary water to a SACO condenser.

This regulation system includes a shutter, a passive actuation device and an active actuation device as described above.

This system can advantageously be arranged in a SACO shell condenser.

In particular, the passive actuation device is preferably located in an enclosure in fluid communication with the grille. The tertiary water level in the grille thus corresponds to the tertiary water level in the enclosure. The passive actuation device can thus advantageously actuate the shutter as a function of this level of tertiary water.

According to a third aspect, the invention also relates to a method of operating a safety condenser according to the first aspect of the invention.

Advantageously, this method comprises at least the following steps:

- In the event of an electrical supply to the active actuation device, regulate the tertiary water supply flow rate according to the active mode, as a function of at least one parameter taken from a temperature measurement of a vapor present in a generator of steam from the nuclear power plant, thermal power to be removed, a cooling cycle to be carried out,

- If there is no power supply to the active actuation device, regulate the supply rate of tertiary water according to the passive mode.

Such a method advantageously makes it possible to improve the level of safety of the CESO, while allowing precise regulation of the supply of CESO in normal operation, that is to say when the electrical supply of the device active actuation is functional.

In normal or ordinary operation, the tertiary water supply rate can be regulated according to the active mode, which allows optimized management of the ODS supply.

In extraordinary operation, in particular in the absence of electrical supply to the active actuation device, the supply rate of tertiary water is regulated according to the passive mode, which confers improved safety on the CESO.

Brief description of the drawings

The aims, objects, as well as the characteristics and advantages of the invention will emerge better from the detailed description of embodiments of the latter which are illustrated by the following accompanying drawings in which:

[Fig.l]

Figure 1 shows a layout of a SACO safety condenser in a REP type nuclear power plant;

[Fig.2A]

FIG. 2A shows an ODS according to an embodiment of the invention, for which the supply of tertiary water is blocked according to an active mode;

[Fig.2B]

FIG. 2B shows an ODS according to an embodiment of the invention, for which the supply of tertiary water is enabled according to an active mode;

[Fig.3A]

FIG. 3A shows an ODS according to an embodiment of the invention, for which the supply of tertiary water is blocked according to a passive mode;

[Fig.3B]

FIG. 3B shows an ODS according to an embodiment of the invention, for which the supply of tertiary water is released in a passive mode;

[Fig.4A]

FIG. 4A shows a detail of the regulation system of the CESO according to an embodiment of the invention and according to a first setting;

[Fig.4B]

FIG. 4B shows a detail of the ODS regulation system according to an embodiment of the invention and according to a second setting.

[Fig.5]

FIG. 5 shows an ODS according to another embodiment of the invention, [fig.56]

FIG. 6 shows an ODS according to yet another embodiment of the invention,

The drawings are given by way of examples and are not limitative of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications. In particular, the relative dimensions of the various components of the CESO, in particular the relative dimensions of the tank, the enclosure and the various conduits and inlets are not representative of reality.

Description of the embodiments

Before starting a detailed review of embodiments of the invention, it is recalled that the invention according to its first aspect optionally includes and in particular the optional features below which can be used in combination or alternatively:

- According to one embodiment, the passive actuation device comprises or is formed of a float.

- According to one embodiment, the active actuation device is connected to the shutter via the passive actuation device. Such a series connection simplifies the design of the regulation system.

- According to one embodiment, the active actuation device is disengageable and has:

• a clutch configuration in which the movement of the shutter depends on the active actuation device, and • a clutch configuration in which the movement of the shutter is independent of the active actuation device.

This advantageously makes it possible to release the strain from the active actuation device on the movement of the shutter. The movement of the shutter can therefore be subject to the movement of the passive actuator.

- According to one embodiment, the disengagement of the active actuation device is ensured by a return spring configured to be tensioned by an electromagnetic force, and to be released in the absence of said electromagnetic force. This configuration makes it possible to avoid blockage of the movement of the shutter by the active actuating device in the absence of electromagnetic force, in particular in the event of absence of electrical supply necessary for the establishment of this force. electromagnetic. The safety of the regulation system is thus improved.

According to one embodiment, the active actuation device is an electromechanical device configured to be in the disengaged configuration in the event of a power supply fault of said active actuation device.

According to one embodiment, the active actuation device is an electromechanical device configured to be in the engaged configuration when it is supplied with electricity.

According to one embodiment, the movement of the shutter is a translational movement along a vertical axis directed according to the earth's gravity. This optimizes the efficiency of the movement transmitted by the float to the shutter.

According to one embodiment, the condenser comprises an adjustable stop and the fully open position of the shutter, corresponding to a maximum cross section of the tertiary supply inlet, is defined by said adjustable stop. This allows the maximum flow of tertiary water supplying the enclosure to be adapted to the maximum effective cooling requirement. This need may vary depending on the maximum thermal power developed by the steam generator.

According to one embodiment, the shutter and the passive activation device are mechanically connected by a rigid transmission rod. The transmission of movement from the passive activation device to the shutter is thus optimized.

According to one embodiment, the active actuation device comprises a toothed wheel configured to, in the engaged configuration of the active actuation device, drive in translation a toothed rod directly or indirectly integral in translation with the shutter.

According to one embodiment, the toothed wheel and the toothed rod mesh with each other to form a pinion / rack link in the engaged configuration of the active actuation device.

According to one embodiment, the toothed wheel does not mesh with the toothed rod in the disengaged configuration of the active actuation device.

- According to one embodiment, the toothed rod is integral with the passive actuation device and the passive actuation device is connected to the shutter by the rigid transmission rod.

- According to one embodiment, the tertiary supply inlet has a passage section and the stop is adjusted so that the maximum passage section in the fully open position is less than said passage section.

- According to one embodiment, the radiator grille has a tertiary outlet in the form of an exhaust duct configured to let escape from the enclosure of the vapor resulting from the vaporization of the tertiary water present within the grille.

- According to one embodiment, the tertiary supply inlet is located at a low point of the enclosure, preferably at the lowest point of said enclosure. The filling and / or emptying of the enclosure can be done according to a principle of communicating vessels.

- According to one embodiment, the enclosure defines a shaped housing to accommodate at least part of the shutter in the open position.

- According to one embodiment, the regulation system is configured so that in the closed position, part of the shutter is located in the housing. Thus, whatever the position of the shutter, the latter is guided in translation by the housing.

- According to one embodiment, the condenser further comprises a tertiary water tank fluidly connected to the tertiary supply inlet. The operation of the CESO can thus be completely passive, the supply of tertiary water in the open position of the shutter being done according to the principle of communicating vessels.

The invention according to its third aspect optionally includes, in particular, the following optional characteristics which can be used in combination or alternatively:

- According to one embodiment, the method further comprises the following steps:

• In the event of power supply to the active actuation device, engage the disengageable active actuation device so that the movement of the shutter is dependent on the active actuation device and independent of the passive actuation device, • If there is no power supply to the active actuation device, disengage the disengageable active actuation device so that the movement of the shutter is independent of the active actuation device and dependent on the device d passive actuation.

- According to one embodiment, the method further comprises the following step: • Defining the fully open position of the shutter by means of an adjustment of a stop.

In the present patent application, the terms "backup condenser", "SACO" and "safety condenser" are synonymous.

The terms "substantially", "approximately", "of the order of" mean taking into account manufacturing and / or measurement tolerances and may in particular correspond "to within 10%".

In this patent application, the vertical reference axis is carried by a direction formed by a plumb line. In the following, a movement or an extension directed along a vertical axis are substantially directed along the vertical reference axis. The height is taken along this vertical reference axis.

The condenser according to the invention will now be described with reference to the figures appended to this application.

As illustrated in FIG. 1, this SACO condenser is connected to the secondary circuit 20a, 20b of a nuclear power plant, in particular a nuclear power plant comprising a third generation pressurized water reactor (PWR).

Typically, this reactor comprises a core 1 in which the fuel 13 is connected to the control rods 12. A primary fluid circuit 10 connected to the core 1 makes it possible to transport the heat released by the core 1. A pump 11 allows a circulation of pressurized primary water in the primary circuit 10.

This primary circuit 10 passes through at least one steam generator 2.

The heart 1, the primary circuit 10, the steam generators 2 are confined in a confinement enclosure 100.

Each steam generator 2 is connected to a secondary circuit forming a loop.

In the following, a single steam generator 2 connected to a single secondary circuit is described, for the sake of clarity.

The steam generator 2 is fluidly connected to the secondary circuit 20a, 20b. A pump 21 allows a secondary water circulation in the secondary circuit 20a, 20b.

The steam generator 2 is supplied with liquid secondary water and produces a secondary water vapor or secondary vapor.

Secondary steam is used to drive turbines 22 for the production of electricity. It is then cooled at a main condenser 4 and condensed in liquid secondary water in order to replenish the steam generator 2.

This main condenser 4 is therefore supplied with secondary steam and produces liquid secondary water intended for the steam generator 2. The main condenser 4 is itself connected to an open fluid circuit 40 comprising lifting pumps 41 , 42 and a cooling tower 400.

An emergency condenser 3 SACO is provided to compensate for a failure of the main supply of the steam generator 2 in liquid secondary water by the main condenser 4.

The SACO condenser is illustrated in detail in Figures 2A, 2B, 3A, 3B, 5 and 6, in different configurations and for different embodiments.

According to a preferred embodiment of the invention, the condenser 3 comprises a heat exchanger having an inlet 303 and an outlet 304.

The so-called secondary input 303 is connected to the part 20b of the secondary circuit where the secondary steam circulates from the steam generator 2. The so-called secondary output 304 is connected to the part 20a of the secondary circuit where the secondary water circulates supplying the steam generator 2.

Valves can be interposed between the parts 20b, 20a of the secondary circuit and the inlet 303 and the outlet 304 of the exchanger, respectively.

This heat exchanger comprises tubes 32, also called tubing, where the secondary vapor condenses. These tubes 32 are preferably mainly vertical in order to more easily evacuate, by gravity, the condensate produced by condensation of the secondary vapor.

The tubes 32 of this heat exchanger are preferably included in a small volume formed by a calender 300.

The radiator grille 300 is supplied with tertiary water at an inlet 331 called the tertiary grille inlet, preferably permanently, by a tertiary circuit. This tertiary circuit is preferably a reservoir 34 configured to passively supply the calender 300 by gravity.

During the cooling of the secondary steam, the tertiary water can vaporize into tertiary steam.

The grille 300 has a so-called tertiary outlet 332, for example in the form of an exhaust duct or an extraction chimney, intended for discharging tertiary steam.

The radiator grille 300 is supplied with tertiary water via a system 31 for regulating the flow rate of tertiary water supply.

This regulation system 31 has a tertiary supply inlet 302 connected to the tertiary circuit, for example to the reservoir 34.

This tertiary water supply regulation system 31 makes it possible to control the level 305 of tertiary water in the calender 300.

The regulation system 31 is configured to regulate the tertiary water supply flow rate through the tertiary supply inlet 302 between a zero flow value and a maximum flow value, for example of the order of a few tens of kg / s.

The regulation system 31 may include a set of regulation members such as a shutter 310, a float 311, an electromechanical device 312, as well as an enclosure 30 configured to be in fluid communication with the calender 300.

The grille 300 may be located in the enclosure 30, as illustrated in Figures 2A, 2B, 3A, 3B and 6.

Alternatively, the grille 300 can be located outside the enclosure 30, as illustrated in Figure 5.

The radiator grille 300 and the enclosure 30 are configured to be in hydrostatic equilibrium, according to the principle of communicating vessels.

According to an example illustrated in Figures 2A, 2B and 3A, 3B, the tertiary supply inlet 302 is directly connected to the enclosure 30 and the grille 300 is immersed in the enclosure 30. The tertiary inlet 331 is located at the bottom of the grille 300, so that when the level 305 of tertiary water increases (or decreases) in the enclosure 30, it simultaneously increases (or decreases) in the grille 300.

According to an example illustrated in Figure 5, the tertiary power input 302 is directly connected to the enclosure 30 and the grille 300 is outside the enclosure 30. The enclosure 30 and the grille 300 are connected at least at a low point, so that the level 305 of tertiary water increases or decreases simultaneously in the enclosure 30 and in the grille 300.

According to an example illustrated in FIG. 6, the tertiary supply input 302 is directly connected to the grille 300 and the grille 300 is immersed in the enclosure 30. Part of the tertiary inputs 331, for example on a side of the grille 300, allow fluid communication with the enclosure 30. The level 305 of tertiary water increases or decreases simultaneously in the enclosure 30 and in the grille 300 if the latter is located above the inlet 331 lowest tertiary in direct communication with enclosure 30.

In order to inject the tertiary water into the enclosure 30 and / or into the grille 300 when the regulation system 31 allows a non-zero supply flow, it is sufficient for the reservoir 34 to contain tertiary water having a tertiary water level above level 305.

The flow of tertiary water contained in the tank 34 is then done according to a principle of communicating vessels between said tank 34, and the enclosure 30 and / or the grille 300. As long as the level of tertiary water contained in the tank 34 is above level 305, the flow of tertiary water is from the tank 34 to the enclosure 30 and / or the grille 300.

The reservoir 34 may be located in height relative to the enclosure 30 and / or the grille 300, as illustrated in FIGS. 5 and 6.

The feed rate of the enclosure 30 can advantageously be regulated so as to maintain a nominal tertiary water level 305 in the enclosure 30.

This flow rate can for example vary depending on the quantity of tertiary steam produced, in order to compensate for the extraction of water in the form of steam which is carried out through the extraction duct 332.

The regulation system 31 advantageously makes it possible to regulate this flow rate.

Regulation of the feed rate at the inlet 302 is done by means of a shutter 310.

The shutter 310 is configured to open or close the inlet 302 connected to the reservoir 34.

The opening or closing is preferably done by vertical translation of the shutter 310, as illustrated in Figures 2A, 2B and 3A, 3B in particular.

The shutter 310 can be translated so as to close the inlet 302, in a closed position, as illustrated in FIGS. 2A and 3A.

The shutter 310 can be translated under the low point of the enclosure 30 and / or of the grille 300 as illustrated in FIGS. 2B and 3B. Thus, tertiary water can pass from the reservoir 34 to the enclosure 30 and / or to the calender 300 by passing over the shutter 310.

If the tertiary supply inlet 302 is located at the low point of the enclosure 30 and / or of the grille 300, provision is advantageously made for a housing 307 formed in a base 306, configured to accommodate at least a portion of the shutter 310, at least when the latter is in the open position.

As illustrated in FIG. 2B, in the open position, most of the height of the shutter 310 is located in the housing 307. Advantageously, the housing 307 is shaped to guide the shutter 310 in translation. In particular, the section of the housing 307 in a horizontal plane corresponds substantially to the section of the shutter 310, naturally providing sufficient clearance to allow easy sliding in the presence of tertiary water.

In order to facilitate the arrival of the shutter 310 at the end of its travel to its open position, the regulation system 31 is configured so that, in the closed position, part of the shutter 310 is already located inside the housing 307. Therefore, whatever its position, the shutter 310 is guided in translation, throughout its travel, by the housing 307.

Advantageously, the housing 307 also makes it possible to maintain the shutter 310 in contact with the tertiary water inlet conduit 302. Thus, even if the pressure exerted by the water column of the reservoir 34 on the shutter 310 is significantly greater than the pressure exerted by the water column of enclosure 30, shutter 310 provides a good seal between these two volumes.

The invention naturally extends to other embodiments. For example, a guidance system can be provided such as one or more vertical rails, the function of which is to ensure the translational guidance of the shutter 310 and / or the plating of the shutter 310 on the supply inlet. tertiary 302. In this case, the shutter has at least one slide which cooperates with its rails.

[0111] According to one possibility, a sealing valve 308 is placed upstream of the regulation system 31, between the reservoir 34 and the inlet 302, as illustrated in FIGS. 2A, 2B. This sealing valve 308 provides sealing when the CESO is not used, in particular when the operating situation of the plant is normal.

In the event of an abnormal operating situation of the power station, when the use of the ODS becomes necessary, this valve 308 can then be opened, for example manually or by means of a battery electric supply, or even via a valve device. explosive, in order to free the passage of tertiary water towards entry 302.

The translation of the shutter 310 is advantageously carried out according to two operating modes of the regulation system 31: an active mode and a passive mode.

A first shutter control device 310 makes it possible to operate the shutter 310 according to the active mode. This first device is preferably the electromechanical device 312.

A second shutter control device 310 allows the shutter 310 to be operated in the passive mode. This second device is preferably the float 311.

The shutter 310 is therefore connected to each of the first and second control devices.

According to an embodiment illustrated in Figures 2A, 2B, 3A, 3B, 5 and 6, the shutter 310 can be connected to the float 311 by means of a rigid transmission rod 316.

The float 311 can be connected to the electromechanical device 312 by means of a toothed rod 315.

The shutter 310 can thus be connected to the electromechanical device 312 via the rigid transmission rod 316, the float 311 and the toothed rod 315 in series. This arrangement simplifies the design and installation of the regulation system 31 within the enclosure 30.

The series 31 regulating members are preferably arranged vertically. This optimizes the translation work. This also makes it possible to reduce the size of the regulation system 31.

The shutter 310, the float 311 and optionally the rods 315, 316 of the system 31 can be guided in vertical translation by structural elements 301.

These structural elements 301 can be arranged in the extension of the housing 307, so as to supplement or replace the guidance produced by the housing 307.

According to one embodiment, the rods 315 and 316 are integral or have a continuity of material to form a single rod and the float 311 is fixed to this single rod.

The electromechanical device 312 may comprise an electrically motorized toothed wheel 314 and configured to cooperate with the toothed rod 315. Typically, the cooperation of the toothed wheel 314 and the toothed rod 315 forms a pinion / rack link.

According to the active regulation mode illustrated in FIGS. 2A, 2B, the toothed wheel 314 is engaged on the toothed rod 315.

The rotation of the toothed wheel 314 therefore makes it possible to vertically translate the shutter 310 between the open position (FIG. 2B) and the closed position (FIG. 2A), independently of the tertiary water level 305 in the enclosure 30 and / or in the grille 300.

The active actuating device 312 is then in the so-called engaged configuration. The vertical position of the shutter 310 and therefore the opening or closing of the tertiary supply inlet 302 are controlled by the electromechanical device 312.

The electromechanical device 312 comprises for example a motor or a geared motor which rotates the toothed wheel 314, directly or by means of intermediate drive systems such as gears or pulleys. The electromechanical device 312 is powered by an electrical energy source, via an electrical network and / or a self-contained battery, for example.

Naturally, the invention extends to other embodiments than a pinion / rack linkage to ensure the control of the rod relative to the electromechanical device.

The electromechanical device 312 advantageously makes it possible to control the opening of the inlet 302 at the low point of the enclosure 30 and / or of the grille 300, so as to regulate the supply rate of tertiary water in the enclosure 30 and / or in the grille 300.

In the absence of power supply to the electromechanical device 312, the regulation system 31 can operate according to a passive regulation mode.

According to this passive regulation mode illustrated in FIGS. 3A, 3B, the toothed wheel 314 is disengaged or disengaged from the toothed rod 315.

This declutching can be done in a known manner via one or more return springs integral with the toothed wheel 314.

These springs are for example put under mechanical tension by the action of an electromagnetic force when the electromechanical device 312 is supplied with electric voltage, so as to engage the toothed wheel 314 on the toothed rod 315. The device active actuation 312 is then in the engaged configuration.

In the event of a power supply fault, the electromagnetic force becomes zero and the springs relax, driving the toothed wheel 314. The toothed wheel 314 then disengages from the toothed rod 315. The active actuating device 312 is then in the disengaged configuration.

The movement of the shutter 310 is then no longer controlled by the electromechanical device 312. The movement of the shutter 310 is then only controlled by the float 311.

The float 311 is advantageously located in the enclosure 30. It therefore moves as a function of the level 305 in the grille 300, without being directly in the grille 300. It is therefore not disturbed and / or degraded by the heat exchanges occurring within the grille 300.

The position of the shutter 310 varies as a function of the tertiary water level 305 in the enclosure 30 and, consequently, of the tertiary water level 305 in the grille 300.

The float 311 and the shutter 310 are arranged so that the shutter 310 completely obstructs the inlet 302 when the tertiary water level 305 is nominal. The shutter 310 is in the closed position and the supply flow is cut off (FIG. 3A).

As soon as the tertiary water level 305 in the enclosure 30 decreases, for example by vaporization of the tertiary water in the grille 300, the float 311 is translated vertically towards the low point.

The shutter 310 is therefore driven in translation by gravity, towards the open position, by freeing a passage for tertiary water from the reservoir 34 towards the enclosure 30 and / or the grille 300. The supply of tertiary water from the radiator grille 300 is established (FIG. 3B), until the tertiary water level 305 is again nominal.

This operation is completely passive. The variation in the tertiary water level 305 in the enclosure 30 is due to the vaporization of the tertiary water in the grille 300 on the one hand, and to the gravity forces exerted on the water column of the reservoir 34 on the other hand.

The float 311 is dimensioned so as to be able to drive the shutter 310 by an Archimedes thrust.

The float 311 can be made of a material having a density much lower than the density of tertiary water, for example between 1 and 240 kg.m ³ .

It can also be in the form of an envelope filled with a sufficient volume of air.

The float 311 advantageously makes it possible to control the opening of the shutter 310 at the level of the inlet 302 at the low point, in particular in the event of a power supply fault.

According to a nonlimiting example of dimensioning, for a concrete shutter 310, of parallelepiped shape, having a density of the order of 2300 kg / m3, dimensions L x 1 xe with L = 1 = 25 cm and e = 5 cm, L being the length, 1 the width and the thickness of the parallelepiped, (making it possible to close an entry 302 of 20 cm in diameter), one will be able to choose a float 311 in cork presenting a density of the around 240 kg / m3 and a volume of around 340 liters.

For a float 311 enclosing air whose density is of the order of 1.4 kg / m3, a volume of approximately 260 liters makes it possible to drive the shutter 310 in translation. These volume examples take into account a coefficient of friction between the concrete of the shutter 310 and the steel of the walls of the housing 307 of the order of 0.4. This coefficient is increased here for safety. The float 311 could have volumes lower than the volumes indicated.

The float 311 may include a cork envelope enclosing air. These combinations of materials are not exhaustive. Other materials can be used.

According to an embodiment illustrated in Figures 4A, 4B, the regulation system 31 further comprises a stop 313 adjustable in height.

This stop 313 can be located for example at the bottom of the housing 307 provided to accommodate the shutter 310 in the open position.

In the open position, the tertiary supply inlet 302 has a maximum passage section S302max.

The setting of the stop 313 makes it possible to modify this maximum passage section S302max, and, in a directly proportional manner, the supply rate of tertiary water.

This stop 313 therefore advantageously allows to define the open position called full opening. This fully open position sets the maximum supply rate for tertiary water.

By adjusting the height of the stop 313, it is therefore possible to modify the maximum supply flow rate in tertiary water.

This makes it possible to adapt the maximum feed rate as a function of the level of residual power of the reactor, the latter evolving during the operating cycle of the core of reactor 1.

The stop 313 can be manually adjusted periodically during the fuel use cycle 13.

The stop 313 can be adjusted to reduce or increase the maximum feed rate. This maximum required flow rate is lower at the start of the fuel use cycle 13 than at the end of the fuel use cycle 13.

Reducing the maximum flow rate saves tertiary cooling water.

The invention is not limited to the embodiments previously described and extends to all the embodiments covered by the claims.

Claims (1)

Claims [Claim 1] Emergency condenser (3) for a steam generator (2) of a nuclear power plant, said condenser (3) comprising: at. a heat exchanger comprising: i. a grille (300) having at least one inlet (331), called the tertiary grille inlet, intended to be supplied with so-called tertiary water, and having an outlet (332), known as the tertiary outlet, intended for discharging said tertiary steam , and ii. at least one tube (32) located in the grille (300) and intended to be at least partially immersed in tertiary water, said at least one tube (32) having an inlet (303), called secondary inlet, intended to receive so-called secondary steam produced by a steam generator (2) of the nuclear power station and having an outlet (304), called a secondary outlet, intended to supply a so-called secondary condensate intended for the steam generator (2), b. a tertiary water supply regulation system (31) having a tertiary supply inlet (302) configured to receive tertiary water, preferably from a reservoir (34), the regulation system (31) being intended to regulate a level (305) of tertiary water in the calender (300), characterized in that said regulation system (31) comprises: vs. - an enclosure (30) configured to be in fluid communication with the calender (300), so as to present said level (305) of tertiary water, d. - a shutter (310) intended to cooperate with said tertiary supply inlet (302), the shutter (310) being movable between: i. an open position authorizing a circulation of tertiary water through said tertiary supply inlet (302), a closed position preventing circulation of tertiary water through said supply inlet ii. tertiary (302), said shutter (310) being actuable by a first actuation device (311) said passive actuation device and by a second actuation device (312) said active actuation device, the passive actuating device (311) being located in the enclosure (30), and configured to move the shutter (310) between the open position and the closed position as a function of the tertiary water level (305) in the enclosure (30), so as to regulate a tertiary water flow in a passive mode, and the active actuation device (312) being configured to move said shutter (310) independently of the tertiary water level (305) in the enclosure (30), so as to regulate the flow rate in an active mode. [Claim 2] Condenser (3) according to any one of the preceding claims, in which the active actuation device (312) is disengageable and has at. a clutched configuration in which the movement of the shutter (310) depends on the active actuation device (312), and b. a disengaged configuration in which the movement of the shutter (310) is independent of the active actuation device (312). [Claim 3] Condenser (3) according to the preceding claim wherein the active actuating device (312) is an electromechanical device configured to be in the engaged configuration when supplied with electricity, and to be in the disengaged configuration in the event of a power supply fault of said active actuation device (312). [Claim 4] Condenser (3) according to any one of the two preceding claims in which the disengagement of the active actuation device (312) is provided by a return spring configured to be tensioned by an electromagnetic force, and to be released in the absence of said electromagnetic force. [Claim 5] Condenser (3) according to any one of claims 2 to 4 wherein the active actuation device (312) comprises a toothed wheel (314) configured to, in the engaged configuration of the active actuation device (312), drive in translation a toothed rod (315) directly or indirectly secured to the shutter (310). [Claim 6] Condenser (3) according to the preceding claim configured so that the toothed wheel (314) and the toothed rod (315) mesh with each other to form a pinion / rack link, and in which in the disengaged configuration of the active actuating device (312) , the toothed wheel (314) does not mesh with the toothed rod (315). [Claim 7] Condenser (3) according to any one of the two preceding claims, in which the toothed rod (315) is integral with the passive actuation device (311) and the passive actuation device (311) is connected to the shutter (310 ) by a rigid transmission rod (316). [Claim 8] Condenser (3) according to any one of the preceding claims, in which the passive actuating device (311) comprises or is formed by a float and in which the movement of the shutter is a translational movement along a directed vertical axis. according to Earth's gravity. [Claim 9] Condenser (3) according to any one of the preceding claims, comprising an adjustable stop (313) and in which the fully open position, corresponding to a maximum passage section (S302max) of the tertiary supply inlet (302), is defined by said adjustable stop (313). [Claim 10] Condenser (3) according to any one of the preceding claims, in which the tertiary supply inlet (302) is located at the lowest point of said enclosure (30), the condenser further comprising a reservoir (34) of tertiary water fluidly connected to said tertiary supply inlet (302) and in which the enclosure (30) has a base (306) defining a housing (307), the housing (307) being shaped to accommodate at least part of the shutter (310) in the open position. [Claim 11] Regulation system (31) of a tertiary water supply to a radiator grille (300) of a heat exchanger of a backup condenser (3) for a steam generator (2) of a nuclear power plant, comprising a shutter (310) movable between an open position and a closed position, configured to regulate a flow of tertiary water at a tertiary supply inlet (302), said shutter (310) being connected to: at. - A first actuation device (311), said passive actuation device, located in an enclosure (30) in fluid communication with the calender (300) and configured to move the shutter (310) between the open position and the closed position according to a tertiary water level (305) in the enclosure, so as to regulate the flow rate in a passive mode, b. - a second actuating device (312), said active actuating device, disengageable and having: i. a clutch configuration in which the active actuating device (312) is connected to the shutter (310) and is configured to move said shutter (310) independently of the tertiary water level (305) in the enclosure (30) , so as to regulate the flow rate in an active mode, ii. a disengaged configuration in which the shutter (310) is movable independently of the active actuation device (312). [Claim 12] Nuclear power station comprising a nuclear reactor, preferably a pressurized water reactor, a steam generator (2) and a backup condenser (3) according to any one of claims 1 to 10. [Claim 13] Method for operating a backup condenser (3) according to any one of claims 1 to 10, comprising at least the following steps: at. If the active actuating device (312) is supplied with electricity, regulate the tertiary water supply flow rate according to the active mode, as a function of at least one parameter taken from a temperature measurement of a vapor present in a steam generator from the nuclear power plant, a thermal power to be removed, a cooling cycle to be carried out, b. If there is no power supply to the active actuation device (312), regulate the supply rate of tertiary water according to the passive mode. [Claim 14] Operating method according to the preceding claim, the condenser comprising a disengageable active actuation device (312), the method further comprising the following steps: at. When the active actuator (312) is powered, engage the active actuator (312) so that the movement of the shutter (310) is dependent on the active actuator (312 ) and independent of the passive actuation device (311), b. If there is no power supply to the active actuator (312), disengage the active actuator (312) so that the movement of the shutter (310) is independent of the actuator active (312) and dependent on the passive actuation device (311). [Claim 15] Operating method according to any one of the two preceding claims, the condenser further comprising an adjustable stop (313) which defines a fully open position of the shutter (310) corresponding to a maximum passage section (S302max ) of the tertiary supply inlet (302), the method further comprising the following step: at. adjust the position of the stop (313) to define the fully open position of the shutter (310), called the fully open position.