JPH0755101A - Steam generator having built-in electromagnetic pump - Google Patents

Abstract

PURPOSE:To enable an electromagnetic pump to be withdrawn without cutting secondary piping, facilitate cooling and improve aseismic characteristics. CONSTITUTION:A sealing device 44 is provided at end part of both an electromagnetic pump supporting casing 36 and an electromagnetic pump suspending casing 37. The sealing device 44 is provided with a sealing part leak hole 49. A stopper 48 is fixed on the inner surface of an elevation pipe 12. A bottom end supporting member 47 for the electromagnetic pump suspending casing 37 is freely removably placed on the stopper 48.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam generator with a built-in electromagnetic pump for use in a secondary cooling device for a liquid metal cooled nuclear reactor which uses liquid metal as a coolant.

[0002]

2. Description of the Related Art A conventional liquid metal cooling type fast breeder reactor cooling apparatus will be described with reference to FIG. That is,
In FIG. 7, reference numeral 1 indicates a reactor vessel of a fast breeder reactor, and in the reactor vessel 1, a core 2, a liquid sodium coolant (hereinafter, referred to as liquid) 3, a primary main circulation pump 4 and an intermediate heat source are provided. The exchanger 5 is housed.

The primary cooling system of a nuclear reactor comprises the liquid 3, a primary main circulation pump 4 and an intermediate heat exchanger 5. The secondary cooling system of the reactor includes an intermediate heat exchanger 5 and a reactor vessel 1
It is composed of a steam generator 6 provided on the outside of the reactor, and a hot leg pipe 8 and a cold leg pipe 9 which are provided through the reactor building wall 7 to connect the both devices.

A liquid inlet pipe 11 is provided at an upper portion of the body barrel 10 of the steam generator 6, while a metal rising pipe 12 having an opening at a lower portion of the body barrel 10 is arranged along a central axis of the body barrel 10. A liquid outlet pipe 13 is connected to the upper end of the rising pipe 12. Further, an electromagnetic pump 15 is arranged in the upper space 14 of the liquid around the upper part of the rising pipe 12.

FIG. 8 is a vertical sectional view showing the detailed structure of the steam generator 6 provided in the secondary reactor cooling system. That is, in the steam generator 6, the main body 10 is supported by the pedestal 16 and the supporting skirt 18
Is supported through. Further, the ascending pipe 12 is arranged in the center of the main body 10, a heat transfer pipe shroud 19 is arranged outside the rising pipe 12, and a large number of heat transfer pipes 20 are arranged in an annular space outside thereof. ing.

By the way, a free liquid surface 21 of the liquid is formed inside the upper part of the main body cylinder 10, and an upper space of the free liquid surface 21 is formed.
14 absorbs the volume change due to the thermal expansion of the liquid.

On the other hand, in the lower part of the main body 10, a water inlet pipe 22 into which water supplied from a water supply pump flows, and a header 23.
The distribution pipe 24 and the water chamber 25 constitute an inlet portion of the water supply as shown in FIG. Further, an outlet steam chamber 26, an outlet steam distribution pipe 27, an outlet steam header 28, and an outlet steam pipe 29 constitute an outlet portion of steam at the upper part of the main body 10.

The inlet pipe 11 is divided into two lines to form a main body 10
On the other hand, the outlet pipe 13 is connected to the electromagnetic pump supporting casing 36 at a position facing the guide pipe 38 of the electromagnetic pump 15 installed at the top of the main body 10.

FIG. 9 is a vertical sectional view showing the inside of the top portion of the steam generator 6 in FIG. 8, in which an electromagnetic pump 15 is provided on the inner circumference of the enlarged diameter portion above the rising pipe 12. The electromagnetic pump 15 has an annular flow path formed in an annular shape between the inner core 30 and the outer core 31.
The outer coil 34 is wound around the inner coil 33 and the outer coil 34 on the inner and outer sides of the 32, and a magnetic field is generated by an electric current from an external electric wire to circulate the liquid.

The rising pipe 12 containing the electromagnetic pump 15 is connected to the outlet pipe 13, and the outlet pipe 13 is connected to the cold leg pipe 9 shown in FIG. In addition, the reference numeral in FIG.
35 is support, 39 is outlet, 40 is outlet nozzle sleeve,
41 is an upper lid, 42 is a hanging flange, and 43 is an outlet plenum.

The cooling device constructed as described above operates as follows. The liquid 3 for cooling the heat generated in the core 2 is circulated by the primary main circulation pump 4 so that the heat is transferred to the secondary cooling system via the intermediate heat exchanger 5.
On the other hand, the liquid of the secondary coolant is circulated by the electromagnetic pump 15 built in the steam generator 6, and the high temperature liquid metal that has absorbed the heat in the intermediate heat exchanger 5 passes through the hot leg pipe 8 and the inlet pipe 11
And flows into the steam generator 6.

Then, the high temperature liquid gives heat to turn the feed water into steam while flowing down the outside of the heat transfer tube 20, and lowers itself to become a low temperature liquid. This low-temperature liquid is the steam generator 6
After rising in a rising pipe 12 which is opened and connected at the lower part of the inside, and is further supplied with a discharge pressure by an electromagnetic pump 15, it is circulated to an intermediate heat exchanger 5 through an outlet pipe 13 and a cold leg pipe 9.

On the other hand, on the water and steam sides, the water supplied from a water supply pump (not shown) flows into the header 23 from the water inlet pipe 22, is distributed in the distribution pipe 24, and is then divided into a plurality of water. Up to room 25.

The feed water distributed from the water chamber 25 to the inside of the heat transfer tube 20 is heat-exchanged with the liquid while rising in the heat transfer tube 20 to rise in temperature and become steam, and then to the outlet steam chamber 26. Reach Then, after passing through the outlet steam distribution pipe 27 and joining at the outlet steam header 28, it flows out from the outlet steam pipe 29 and is sent to a steam turbine (not shown).

[0015]

According to the above-mentioned conventional cooling device, the electromagnetic pump 15 in the steam generator 6 has the outlet pipe 13
Since a part of the discharge fluid of the electromagnetic pump 15 does not flow out to the outlet pipe 13 in order to draw out the structure without cutting it, the electromagnetic pump suspending casing 37 and the electromagnetic pump supporting casing 36 pass through the gap. It was circulating at the inlet of the electromagnetic pump 15.

This recirculation deteriorates the performance of the electromagnetic pump 15, and the recirculation flow rate largely depends on the gap. Therefore, there is a problem that the gap changes due to a change in temperature distribution due to operating conditions and the recirculation flow rate also changes. .

The circulating flow rate is also expected to remove the heat generated by the electromagnetic pump 15 from the outer surface of the electromagnetic pump suspension casing 37. However, when the circulating flow rate changes as described above, the amount of heat removed by the electromagnetic pump 15 changes, and the temperature of the outer core 31 and the outer coil 34 inside the electromagnetic pump 15 becomes unstable, which is not preferable for structural soundness. It becomes a state.

The present invention has been made to solve the above problems, and a seal device is provided between the casing for suspending the electromagnetic pump and the casing for supporting the electromagnetic pump to limit the flow rate of a part of the discharge fluid of the electromagnetic pump. As a result, it can be recirculated to the inlet of the electromagnetic pump, the electromagnetic pump can be pulled out without cutting the secondary system piping, and the entire electromagnetic pump can be installed in a cold leg temperature atmosphere to facilitate cooling and improve earthquake resistance. To provide a steam generator with a built-in electromagnetic pump.

[0019]

According to the present invention, a liquid metal inlet pipe is provided in an upper portion of a body barrel of a steam generator, and a liquid metal riser pipe having an opening at a lower portion of the body barrel is axially provided in the body barrel. An electromagnetic pump is provided at the upper end of the liquid metal rising pipe, and the upper portion of the electromagnetic pump is supported by a casing for suspending the electromagnetic pump through a support, and the outside of the casing for suspending the electromagnetic pump is the electromagnetic pump. An electromagnetic pump built-in type steam generator, which is surrounded by a supporting casing, wherein an outer side of the electromagnetic pump supporting casing is fixed to the main body body, and a liquid metal outlet pipe is provided on an upper side surface of the supporting casing. A sealing device is provided between the lower end of the hanging casing and the lower end of the electromagnetic pump supporting casing.

[0020]

In the present invention, the liquid metal discharged from the electromagnetic pump enters the electromagnetic pump suspension casing and is then discharged from the discharge port provided inside the electromagnetic pump suspension casing. It flows out from the outlet pipe connected to the pump supporting casing.

Further, the liquid metal flowing out into the gap between the casing for suspending the electromagnetic pump and the casing for supporting the electromagnetic pump descends through the gap, and the flow rate is controlled by the sealing device to return to the suction port of the electromagnetic pump.

Therefore, a part of the liquid metal discharged from the electromagnetic pump capable of pulling out the electromagnetic pump without cutting the pipe can return to the electromagnetic pump suction port at a controlled flow rate.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a steam generator with a built-in electromagnetic pump according to the present invention will be described with reference to FIGS. FIG. 1 shows a steam generator with a built-in electromagnetic pump according to the present invention,
FIG. 2 is an enlarged view showing the vicinity of the electromagnetic pump and the seal device in FIG. In FIGS. 1 and 2, the same parts as those of the conventional example of FIGS. 7 to 9 are designated by the same reference numerals, and the description of the overlapping parts will be omitted.

In FIG. 1, the electromagnetic pump 15 is a casing for suspending the electromagnetic pump from a casing 36 for supporting the electromagnetic pump.
It is supported by 37 and installed in the rising pipe 12. Outlet piping 13
2 is welded to the electromagnetic pump supporting casing 36 as shown in FIG. 2, and is not joined to the electromagnetic pump suspension casing 37. The inlet portion 17 of the electromagnetic pump 15 is inserted into the rising pipe 12 via a bellows 45 as a sealing device 44.

That is, the bellows 45 is used as the sealing device 44 of the first embodiment. The bellows 45 is a lower end portion of the casing 37 for suspending the electromagnetic pump and a lower end support member.
It is provided between 47 and. The inside of the bellows 45 is covered with a bellows cover 46, and the bellows cover 46 is attached to the lower end support member 47.

The lower end support member 47 is placed on a stopper 48 fixed to the inner surface of the rising pipe 12. A seal portion leak hole 49 is formed in the lower end support member 47. A leak hole 50 is formed in the electromagnetic pump suspension casing 37 at the outlet plenum 43.

A gap 51 is provided between the electromagnetic pump support casing 36 and the electromagnetic pump suspension casing 37 to allow a fluid to flow therein, and spacers 52 are interposed in the gap 51 at appropriate intervals.

Thus, in the first embodiment, the fluid discharged from the electromagnetic pump 15 flows out to the outlet pipe 13 via the outlet plenum 43. At that time, part of the fluid leaks
50 Casing for suspending electromagnetic pump 37 through gap 51
It flows down while cooling the outside, reaches the inlet portion 17 of the electromagnetic pump 15 through the seal leak hole 49.

The seal leak holes 49 and the leak holes 50 are provided at several locations in the circumferential direction, and the casing 37 for suspending the electromagnetic pump is provided.
As well as being able to cool the outer surface of the
The diameter is reduced so that the flow rate does not become excessive.

The bellows 45 of the sealing device 44 absorbs the difference in thermal expansion between the electromagnetic pump supporting casing 36 and the electromagnetic pump suspension casing 37 due to the temperature difference. This makes it possible to secure the axial relative displacement while maintaining the sealing performance, and also to absorb the dimensional error at the time of manufacturing and assembling. Further, the bellows cover 46 is an electromagnetic pump 15
It is installed to suppress the vibration of the bellows 45 due to the flow velocity of the fluid at the inlet portion 17 of the.

The electromagnetic pump 15 is fixed to the electromagnetic pump supporting casing 36 via a suspension flange 42, and the outside of the electromagnetic pump suspending casing 37 serves as a fluid leakage channel, so that mechanical support is provided. There was no. Therefore, the spacer 52 is installed to improve the earthquake resistance of the electromagnetic pump 15.

With the above construction, the electromagnetic pump 15 can send the fluid out of the steam generator without being directly connected to the outlet pipe 13, and the electromagnetic pump 15 removes the hanging flange 42 from the electromagnetic pump supporting casing 36. Only then can the outlet pipe 13 be pulled out without being cut.

Further, a uniform and limited amount of fluid flows down between the electromagnetic pump supporting casing 36 and the electromagnetic pump suspension casing 37 due to the action of the leak hole 50 and the seal portion leak hole 49, and the electromagnetic pump 15 It is possible to uniformly cool only the required amount on the outer side of the electromagnetic pump 15 and minimize the reduction in efficiency of the electromagnetic pump 15. Further, the installation of the spacer 52 improves the earthquake resistance of the electromagnetic pump 15.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a portion of the sealing device 44 of the second embodiment and its periphery, and other portions are omitted since they are the same as those in FIG. The difference of the second embodiment from the first embodiment is a sealing device using a seal ring 53 instead of the sealing device by the bellows 45 shown in FIG.

That is, the casing for suspending the electromagnetic pump
The outer surface of the lower end of 37 is provided with an annular groove 54 in which the seal ring 53 can be installed in two steps, and the outer periphery of the seal ring 53 can slide with the inside of the rising pipe 12.

With such a structure, the relative displacement in the axial direction can be maintained while maintaining the sealing performance, similarly to the sealing device 44 by the bellows 45, and the flow rate of the fluid flowing from the gap 51 and the leak hole 50 is also a limited amount. Can be managed as. The number of stages of the seal ring 53 depends on the limit value of the leak flow rate, and is not limited to two stages.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a case where a hydrodynamic bearing mechanism 61 is used instead of the sealing device 44 by the bellows 45 shown in FIG. 2 as in FIG. A box 57 having a fluid inflow hole 55 and a fluid outflow hole 56 is installed at the lower end of the electromagnetic pump suspension casing 37, and a pocket member 59 having a pocket 58 is installed at the upper end of the ascending pipe 12, facing the pocket 58. Let

The fluid flowing in through the inflow hole 55 is the shaft plenum 60.
Then, the static pressure rises, enters the pocket 58 through the plurality of outflow holes 56 provided around the box 57, flows out from the lower end of the pocket 58, and reaches the inlet portion 17 of the electromagnetic pump 15.

The flow of this fluid allows the casing 37 for suspending the electromagnetic pump to maintain a constant gap 51 with the casing 36 for supporting the electromagnetic pump without being restricted in axial displacement, and the flow rate thereof is also controlled. It is possible to obtain a large amount.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment, the bellows is the same as in FIG.
A labyrinth mechanism 62 is used instead of the sealing device by 45. That is, the labyrinth mechanism 62 is provided at a position facing the rising pipe 12 on the outer surface of the lower end portion of the electromagnetic pump suspension casing 37.
Is provided. The labyrinth mechanism 62 increases flow resistance by repeatedly contracting and expanding the fluid flowing through the gap 51, and has an effect of ensuring a sealing function.

Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows only the upper part of this embodiment in an enlarged scale, and the other lower parts are omitted because they are similar to FIG. That is, in the first embodiment, the outlet pipe 13 is shown as being installed in the electromagnetic pump supporting casing 36 at only one location.
In this embodiment, the outlet pipes 13 are installed facing each other at two places.

This is installed in order to make the flow state in the outlet plenum 43 symmetrical so that the fluid flowing out of the annular flow path 32 of the electromagnetic pump 15 can flow into the outlet pipe 13 uniformly. Yes, prevention of fluid vibration
This contributes to reduction of flow loss in the outlet plenum 43.

The work required when the plant is started is to fill the electromagnetic pump combined steam generator with fluid. At this time, the gas is full before filling, and if the fluid is introduced, the gas is not completely discharged due to the relative relationship between the outlet plenum 43 and the outlet pipe 13. If there is a gas pool in the outlet plenum 43, flow stability will be impaired and flow loss will increase, which is not preferable.

Therefore, the nozzle 63, the stop valve 64, the pot 65,
By installing the gas pipe 66 and the gas stop valve 67 on the upper lid 41, the gas accumulated in the outlet plenum 43 can be discharged. A liquid level gauge 69 is installed in the pipe 68 to detect whether or not gas is present in the outlet plenum 43.

Further, since the fluid in the outlet plenum 43 is a portion immediately after heat exchange in the steam generator, it is a good condition for monitoring the temperature condition in the plant. Although it is installed in the outlet pipe 13 in the current plant, it is possible to install the well 70 in the upper lid 41 and install the thermocouple 71 therein in order to improve detection sensitivity and maintainability.

When the heat transfer tube 20 of the steam generator 6 is damaged, hydrogen is generated in the fluid and there is a method of detecting the hydrogen to detect the heat transfer tube damage. In this case, since it is advantageous to make the detection time as early as possible, a fluid is introduced into the upper lid 41 from the inlet pipe 72, the presence or absence of hydrogen is checked by the hydrogen meter 73, and returned by the outlet pipe 74.

By this means, conventional plant outlet piping
The detection time is faster than the one with the hydrogen meter 73 installed in 13,
Immediate measures can be taken to prevent the scale of damage to the heat transfer tube 20 from increasing.

[0048]

According to the present invention, the electromagnetic pump can be pulled out without cutting the pipe. Further, by installing a sealing device at the fitting portion between the electromagnetic pump and the steam generator, the leakage flow rate is limited, so that it is possible to uniformly cool the electromagnetic pump and maintain pump performance. In addition, we provide vibration resistance by installing spacers, vibration prevention by degassing, improved operability, sensitive temperature measurement, and measurement of the presence or absence of hydrogen.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of an electromagnetic pump built-in type steam generator according to the present invention.

FIG. 2 is an enlarged vertical sectional view showing the electromagnetic pump and its surroundings in FIG.

FIG. 3 is a vertical cross-sectional view showing a main part of a second embodiment of a steam generator with a built-in electromagnetic pump according to the present invention.

FIG. 4 is a vertical cross-sectional view showing the essential parts of a third embodiment of the electromagnetic pump built-in type steam generator according to the present invention.

FIG. 5 is a vertical cross-sectional view showing the main parts of a fourth embodiment of a steam generator with an electromagnetic pump according to the present invention.

FIG. 6 is a longitudinal sectional view showing an enlarged main part of a fifth embodiment of a steam generator with a built-in electromagnetic pump according to the present invention.

FIG. 7 is a system diagram showing a connection relationship with a steam generator used in a cooling device for a liquid metal cooled nuclear reactor.

FIG. 8 is a vertical cross-sectional view showing a conventional steam generator with a built-in electromagnetic pump.

FIG. 9 is an enlarged vertical sectional view showing the electromagnetic pump and its surroundings in FIG.

[Explanation of symbols]

1 ... Reactor equipment, 2 ... Reactor core, 3 ... Liquid metal coolant, 4 ...
Primary main circulation pump, 5 ... Intermediate heat exchanger, 6 ... Steam generator, 7 ... Reactor building wall, 8 ... Hot leg piping, 9 ... Cold leg piping, 10 ... Main body, 11 ... Inlet piping, 12 ... Rise pipe, 13 ... Exit piping, 14 ... Liquid upper space, 15 ... Electromagnetic pump, 16 ... Stand, 17 ... Inlet, 18 ... Support skirt, 19 ... Heat transfer tube shroud, 20 ... Heat transfer tube, 21 ... Free liquid level, 22 ... Water Inlet piping, 23 ... Header, 24 ... Distribution piping, 25 ... Water chamber, 26 ... Outlet steam chamber, 27 ... Outlet steam distribution pipe, 28 ... Outlet steam header, 29
… Outlet steam pipe, 30… Internal core, 31… External core, 32… Annular flow path, 33… Inner coil, 34… Outer coil, 35… Support, 36… Casing for electromagnetic pump support, 37… For suspending electromagnetic pump Casing, 38 ... Guide tube, 39 ... Discharge port, 40 ... Outlet nozzle sleeve, 41 ... Top lid, 42 ... Hanging flange, 43
… Exit plenum, 44… Sealing device, 45… Bellows, 46
... Bellows cover, 47 ... Lower end support member, 48 ... Stopper,
49 ... Seal section leak hole, 50 ... Leak hole, 51 ... Gap, 52
... Spacer, 53 ... Seal ring, 54 ... Annular groove, 55 ... Inflow hole, 56 ... Outflow hole, 57 ... Box, 58 ... Pocket, 59 ... Pocket member, 60 ... Shaft plenum, 61 ... Fluid bearing mechanism, 62 ...
Labyrinth mechanism, 63 ... Nozzle, 64 ... Stop valve, 65 ... Pot, 66 ... Gas pipe, 67 ... Gas stop valve, 68 ... Pipe, 69 ... Level gauge, 70 ... Well, 71 ... Thermocouple, 72 ... Inlet pipe , 73 ...
Hydrogen meter, 74 ... Exit pipe.

Claims (6)

[Claims] 1. A liquid metal inlet pipe is provided in an upper portion of a body barrel of a steam generator, and a liquid metal rising pipe having an opening is provided in a lower portion of the body barrel in an axial direction in the body barrel. An electromagnetic pump is disposed on the upper end of the electromagnetic pump, the upper part of the electromagnetic pump is supported by a casing for suspending the electromagnetic pump through a support, and the outside of the casing for suspending the electromagnetic pump is surrounded by the casing for supporting the electromagnetic pump. An electromagnetic pump built-in type steam generator in which an outer side of the casing for supporting an electromagnetic pump is fixed to the main body body, and a liquid metal outlet pipe is provided on an upper side surface of the supporting casing, wherein a lower end portion of the casing for suspending the electromagnetic pump. A steam generator with a built-in electromagnetic pump, characterized in that a sealing device is provided between the electromagnetic pump and the lower end of the casing for supporting the electromagnetic pump. 2. The sealing device is provided with a bellows between a lower end portion of the electromagnetic pump suspension casing and the electromagnetic pump supporting casing, and a sealing member leak hole is provided in a fixing member for fixing the lower end portion of the bellows. The steam generator with a built-in electromagnetic pump according to claim 1, wherein the steam generator is provided. 3. The electromagnetic pump built-in type according to claim 1, wherein the seal device is provided with a seal ring at a position facing the rising pipe on the outer surface of the lower end portion of the electromagnetic pump suspension casing. Steam generator. 4. The sealing device comprises a pocket provided on an inner surface of an upper portion of the rising pipe, and a box having a liquid metal inflow / outflow hole provided on an outer surface of a lower end portion of the electromagnetic pump suspension casing facing the pocket. The steam generator with a built-in electromagnetic pump according to claim 1, characterized in that. 5. The electromagnetic pump built-in type steam according to claim 1, wherein the sealing device is provided with a labyrinth mechanism at a position facing the rising pipe on an outer surface of a lower end portion of the electromagnetic pump suspension casing. Generator. 6. A plurality of liquid metal outlet pipes are provided at equal intervals in a radial direction of the electromagnetic pump supporting casing, and a degassing device is provided on an upper lid that closes an upper end opening of the electromagnetic pump suspension casing. Claim 1 characterized by the above-mentioned.
A steam generator with a built-in electromagnetic pump.