JP3207627B2 - Steam generator with built-in electromagnetic pump - Google Patents

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 system of a liquid metal cooled nuclear reactor using liquid metal as a coolant.

[0002]

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

[0003] The primary cooling system of the 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 the intermediate heat exchanger 5 and the reactor vessel 1
And a hot-leg pipe 8 and a cold-leg pipe 9 disposed through the reactor building wall 7 to connect these two devices.

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

FIG. 8 is a longitudinal sectional view showing the detailed structure of the steam generator 6 provided in the reactor secondary cooling system. That is, the steam generator 6 has the main body 10 mounted on the gantry 16 and the support skirt 18.
Is supported through. Further, the riser tube 12 is disposed at a central portion in the main body 10, a heat transfer tube shroud 19 is disposed outside the riser tube 12, and a number of heat transfer tubes 20 are disposed in an annular space outside the heat transfer tube shroud 19. ing.

[0006] A free liquid surface 21 of liquid is formed inside the upper part of the main body 10, and a space above the free liquid surface 21 is formed.
14 absorbs the volume change due to the thermal expansion of the liquid.

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

[0008] The inlet pipe 11 is branched into two lines,
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 on the top of the main body 10.

FIG. 9 is a longitudinal sectional view showing the inside of the top of the steam generator 6 in FIG. 8, and an electromagnetic pump 15 is provided on the inner circumference of the enlarged portion at the top of the riser 12. The electromagnetic pump 15 has an annular flow path formed between the inner core 30 and the outer core 31 in an annular shape.
It is configured by a two-stator coil system in which an outer coil 34 is wound around an inner coil 33 inside and outside a 32. A magnetic field is generated by a current from an external electric wire to circulate the liquid.

[0010] The riser pipe 12 containing the electromagnetic pump 15 is connected to an outlet pipe 13, and the outlet pipe 13 is connected to the cold leg pipe 9 shown in FIG. In addition, the code in FIG.
35 is support, 39 is outlet, 40 is outlet nozzle sleeve,
41 is an upper lid, 42 is a suspension flange, and 43 is an outlet plenum.

The cooling device configured as described above operates as follows. Heat is transferred to the secondary cooling system via the intermediate heat exchanger 5 by circulating the liquid 3 for cooling the heat generated in the reactor core 2 by the primary main circulation pump 4.
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 absorbed by 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 so as to convert the feed water into steam while flowing down the outside of the heat transfer tube 20, and the temperature of the liquid itself drops to become a low-temperature liquid. This low-temperature liquid is supplied to the steam generator 6.
It rises in a riser pipe 12 which is opened and connected at the lower part of the inside, and after being given a discharge pressure by an electromagnetic pump 15, is returned to the 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, water supplied from a water supply pump (not shown) flows into a header 23 from a water inlet pipe 22, is flow-distributed by a distribution pipe 24, and is divided into a plurality of water streams. It reaches room 25.

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

[0015]

According to the conventional cooling device described above, the electromagnetic pump 15 in the steam generator 6 is connected to the outlet pipe 13.
Part of the discharge fluid of the electromagnetic pump 15 does not flow out to the outlet pipe 13 through a gap formed by a casing 37 for suspending the electromagnetic pump and a casing 36 for supporting the electromagnetic pump. It circulated to the inlet of the electromagnetic pump 15.

This recirculation degrades 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 the temperature distribution due to the operation state and the recirculation flow rate also changes. .

It is also expected that the recirculation flow removes heat generated by the electromagnetic pump 15 from the outer surface of the casing 37 for suspending the electromagnetic pump. However, when the recirculation 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 in the electromagnetic pump 15 becomes unstable. State.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a seal device is provided between a casing for suspending an electromagnetic pump and a casing for supporting the electromagnetic pump to restrict a part of a discharge fluid of the electromagnetic pump. Can be recirculated to the inlet of the electromagnetic pump, the electromagnetic pump can be pulled out without cutting the secondary 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 at an upper portion of a main body of a steam generator, and a liquid metal riser having an opening at a lower portion of the main body is axially inserted into the main body. An electromagnetic pump is provided at the upper end of the liquid metal riser, the upper part of the electromagnetic pump is supported by a casing for suspending the electromagnetic pump via a support, and the outside of the casing for suspending the electromagnetic pump is disposed outside the electromagnetic pump. In a steam generator with a built-in electromagnetic pump, wherein the electromagnetic pump is surrounded by a supporting casing, the outside of the electromagnetic pump supporting casing is fixed to the main body, and a liquid metal outlet pipe is provided on an upper side surface of the supporting casing. A sealing device is provided between a lower end of the hanging casing and a lower end of the electromagnetic pump supporting casing.

[0020]

According to the present invention, the liquid metal discharged from the electromagnetic pump enters the casing for suspending the electromagnetic pump and then is discharged from the discharge port provided in the casing for suspending the electromagnetic pump. It flows out of the outlet pipe connected to the pump supporting casing.

The liquid metal that has flowed out into the gap between the casing for suspending the electromagnetic pump and the casing for supporting the electromagnetic pump descends in the gap, and the flow rate is controlled by the sealing device to return to the electromagnetic pump suction port.

Therefore, a part of the liquid metal discharged from the electromagnetic pump, which can pull out the electromagnetic pump without cutting the pipe, can return to the electromagnetic pump inlet 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 of the vicinity of the electromagnetic pump and the sealing device in FIG. 1 and 2, the same parts as those of the conventional example of FIGS. 7 to 9 are denoted by the same reference numerals, and the description of the duplicated parts will be omitted.

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

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

The lower end support member 47 is mounted on a stopper 48 fixed to the inner surface of the riser tube 12. The lower end support member 47 has a seal portion leak hole 49 formed therein. The electromagnetic pump suspension casing 37 has a leak hole 50 located at the outlet plenum 43.

A gap 51 is provided between the electromagnetic pump supporting casing 36 and the electromagnetic pump suspending casing 37 to such an extent that a fluid flows, and a spacer 52 is interposed in the gap 51 at an appropriate interval.

In the first embodiment, the fluid discharged from the electromagnetic pump 15 flows out of the outlet pipe 13 through the outlet plenum 43. At that time, part of the fluid leaks
50 The casing for hanging the electromagnetic pump 37 through the gap 51
It flows down while cooling the outside, and reaches the inlet 17 of the electromagnetic pump 15 through the seal part leak hole 49.

The seal part leak holes 49 and the leak holes 50 are provided at several places in the circumferential direction, and the casing 37 for suspending the electromagnetic pump is provided.
The outer surface of the can be uniformly cooled,
The diameter is reduced so that the flow rate does not become excessive.

The bellows 45 of the sealing device 44 absorbs a difference in thermal expansion caused by a temperature difference between the casing 36 for supporting the electromagnetic pump and the casing 37 for suspending the electromagnetic pump. This makes it possible to ensure the relative displacement in the axial direction while maintaining the sealing performance, and to absorb the dimensional error at the time of manufacturing and assembling. In addition, the bellows cover 46 is
The bellows 45 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 air conditioner.

The electromagnetic pump 15 is fixed to a casing 36 for supporting the electromagnetic pump via a suspension flange 42. Since the outside of the casing 37 for suspending the electromagnetic pump is a fluid leakage flow path, it is mechanically supported. There was no. Therefore, the spacer 52 is provided to improve the earthquake resistance of the electromagnetic pump 15.

With the above configuration, the electromagnetic pump 15 can send out the fluid to the outside of the steam generator without being directly connected to the outlet pipe 13, and the electromagnetic pump 15 removes the suspension flange 42 from the casing 36 for supporting the electromagnetic pump. It is possible to pull out the outlet pipe 13 without cutting it alone.

Further, a uniform and limited amount of fluid flows down between the electromagnetic pump supporting casing 36 and the electromagnetic pump suspending casing 37 due to the action of the leak hole 50 and the seal portion leak hole 49. Only the required amount can be uniformly cooled, and a decrease in the efficiency of the electromagnetic pump 15 can be minimized. In addition, the provision 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 part of the sealing device 44 of the second embodiment and its periphery, and other parts are omitted because they are the same as those in FIG. The difference between the second embodiment and the first embodiment is a sealing device using a seal ring 53 instead of the sealing device using the bellows 45 shown in FIG.

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

With such a configuration, it is possible to perform relative displacement in the axial direction 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 limited. It can be managed as The number of stages of the seal ring 53 is not limited to two since it depends on the limit value of the leak flow rate.

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 in place of the sealing device 44 using the bellows 45 shown in FIG. A box 57 having a fluid inflow hole 55 and a fluid outflow hole 56 is provided at the lower end of the electromagnetic pump suspension casing 37, and a pocket member 59 having a pocket 58 is provided at the upper end of the riser pipe 12. Let it.

The fluid flowing from the inflow hole 55 is supplied to 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 17 of the electromagnetic pump 15.

By the flow of the fluid, the gap 37 between the electromagnetic pump suspension casing 37 and the electromagnetic pump supporting casing 36 can be kept constant without restraining the axial displacement, and the flow rate thereof is also controlled. Can be reduced.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment, as in FIG.
A labyrinth mechanism 62 is used instead of the sealing device 45. That is, the labyrinth mechanism 62 is located at a position facing the rising pipe 12 on the outer surface of the lower end portion of the casing 37 for suspending the electromagnetic pump.
Is provided. The labyrinth mechanism 62 increases the 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 portion of this embodiment in an enlarged manner, and the other lower portions are omitted because they are similar to FIG. That is, in the first embodiment, the outlet pipe 13 is provided only at one place in the electromagnetic pump supporting casing 36.
In this embodiment, the outlet pipes 13 are provided at two locations facing each other.

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 uniformly flow into the outlet pipe 13. To prevent fluid vibration,
This contributes to reducing the flow loss in the outlet plenum 43.

As a necessary operation when starting up the plant, there is a fluid filling of the electromagnetic pump united steam generator. At this time, before filling, the gas is full, 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 gas remains in the outlet plenum 43, the flow stability is impaired, and the flow loss increases, 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 provided in the pipe 68 to detect whether or not gas exists 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 state in the plant. In the current plant, it is installed at the outlet pipe 13. However, in order to improve detection sensitivity and maintainability, it is possible to install the well 70 in the upper lid 41 and install the thermocouple 71 therein.

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 heat transfer tube damage by detecting the hydrogen. In this case, since it is advantageous to make the detection time as short as possible, a fluid is introduced into the upper lid 41 from the inlet pipe 72 and the presence or absence of hydrogen is checked by the hydrogen meter 73 and returned through the outlet pipe 74.

By this means, the outlet piping of a conventional plant
The detection time is faster than the one that installs a hydrogen meter 73 on 13
A measure for preventing the damage scale of the heat transfer tube 20 from expanding can be made immediately.

[0048]

According to the present invention, the electromagnetic pump can be pulled out without cutting the pipe. In addition, by installing a sealing device at a fitting portion between the electromagnetic pump and the steam generator, the leakage flow rate is limited, thereby enabling uniform cooling of the electromagnetic pump and maintenance of pump performance. Furthermore, it provides seismic resistance improvement by installing spacers, vibration prevention by degassing, improvement in operability, sensitive temperature measurement, and measurement of the presence or absence of hydrogen.

[Brief description of the drawings]

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

FIG. 2 is an enlarged longitudinal sectional view showing the electromagnetic pump and its periphery in FIG. 1;

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

FIG. 4 is a longitudinal sectional view showing a main part of a third embodiment of the steam generator with a built-in electromagnetic pump according to the present invention.

FIG. 5 is a longitudinal sectional view showing a main part of a fourth embodiment of the steam generator with a built-in electromagnetic pump according to the present invention.

FIG. 6 is an enlarged vertical sectional view showing a main part of a fifth embodiment of the 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 of a liquid metal cooled reactor.

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

FIG. 9 is an enlarged longitudinal sectional view showing the electromagnetic pump and its periphery in FIG. 8;

[Description of Signs] 1 ... Reactor vessel, 2 ... 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 trunk, 11: Inlet piping, 12: Ascending pipe, 13 ... Outlet piping, 14 ... Liquid head 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 pipe, 25 water chamber, 26 outlet steam chamber, 27 outlet steam distribution pipe, 28 outlet steam header, 29
… Outlet steam piping, 30… Inner core, 31… Outer core, 32… Circular flow path, 33… Inner coil, 34… Outer coil, 35… Support, 36… Electromagnetic pump support casing, 37… Electromagnetic pump suspension Casing, 38… Guide tube, 39… Discharge port, 40… Outlet nozzle sleeve, 41… Top cover, 42… Suspension flange, 43
… Exit plenum, 44… Sealing device, 45… Bellows, 46
... bellows cover, 47 ... lower end support member, 48 ... stopper,
49… Seal part 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 ... outlet pipe.

Claims (6)

(57) [Claims] A liquid metal inlet pipe provided at an upper portion of a main body of the steam generator, a liquid metal riser having an opening at a lower portion of the main body provided axially in the main body; An electromagnetic pump is arranged at the upper end of the electromagnetic pump, the upper part of the electromagnetic pump is supported by a casing for suspending the electromagnetic pump via a support, and the outside of the casing for suspending the electromagnetic pump is surrounded by a casing for supporting the electromagnetic pump, In a steam generator with a built-in electromagnetic pump in which the outside of the casing for supporting the electromagnetic pump is fixed to the main body and a liquid metal outlet pipe is provided on an upper side surface of the supporting casing, a lower end of the casing for hanging the electromagnetic pump is provided. A sealing device provided between the electromagnetic pump supporting casing and a lower end of the electromagnetic pump supporting casing. 2. The sealing device according to claim 1, further comprising a bellows provided between a lower end of the casing for suspending the electromagnetic pump and the casing for supporting the electromagnetic pump, and a fixing member for fixing the lower end of the bellows having a seal part leak hole. The steam generator with a built-in electromagnetic pump according to claim 1, wherein: 3. The built-in type electromagnetic pump according to claim 1, wherein the sealing device is provided with a seal ring at a position facing the riser pipe on the outer surface of a lower end portion of the casing for hanging the electromagnetic pump. Steam generator. 4. The sealing device is provided with a pocket on an inner surface of an upper part of the riser pipe, and a box having a liquid metal inlet / outlet port on an outer surface of a lower end of the casing for suspending the electromagnetic pump facing the pocket. The steam generator with a built-in electromagnetic pump according to claim 1. 5. The steam with a built-in electromagnetic pump 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 casing for hanging the electromagnetic pump. 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 gas venting device is provided on an upper lid for closing an upper end opening of the electromagnetic pump suspending casing. Claim 1 characterized by the following:
A steam generator with a built-in electromagnetic pump as described.