WO2018114660A1

WO2018114660A1 - Pump arrangement, and nuclear reactor having a pump arrangement of this type

Info

Publication number: WO2018114660A1
Application number: PCT/EP2017/083006
Authority: WO
Inventors: Christoph Jäger; Paul Scherer
Original assignee: KSB SE & Co. KGaA
Priority date: 2016-12-20
Filing date: 2017-12-15
Publication date: 2018-06-28
Also published as: DE102016225533A1; EP3559471A1; CN110073110A; DE102016225533B4; EP3559471B1; CN110073110B

Abstract

The invention relates to a pump arrangement (2) for arranging on a nuclear reactor and for conveying exchanger liquid which is heated in the reactor, having a motor part (4) and a pump part (3) which has a housing (7), wherein a diffuser (19) and a valve device (35) are arranged in an interior (14) of the housing (7), and an opening (25) of the diffuser (19) is configured as a valve seat for a valve body (38) of the valve device (35).

Description

description

Pump assembly and nuclear reactor with such a pump assembly

The invention relates to a pump arrangement for the arrangement of a nuclear reactor and for conveying in the reactor heated transfer liquid, with a motor teii and a housing having a pump part. Furthermore, the invention relates to a nuclear reactor with such a pump arrangement.

Such pumps are used, for example, in the field of nuclear reactors, including in small-capacity reactors (small modular reactors). These reactors often have a plurality of circumferentially distributed pump assemblies serving as recirculating pumps. In most cases, the motor is arranged vertically above or below the pump part, in some cases, a horizontal design of the pump can be found. Each pump assembly in this case has its own pressure housing, which is connected via an inlet and outlet with the pressure housing of the reactor. In pressurized water reactors, the pumps are used to promote the reactor liquid heated in the reactor in a closed circuit by a heat exchanger designed as a steam generator. In boiling water reactors, these pumps provide internal circulation within the primary circuit.

Due to the multiple arrangement and the associated parallel operation, it is possible on the one hand to regulate the performance of the reactor by switching off individual pumps, on the other hand, the remaining operation can be restricted maintained in case of failure of one or more pumps. However, the disconnected flowed through backward or failed pumps. In order to avoid reverse rotation and to increase the flow resistance and thus limit the volumetric losses, such pump assemblies are provided with a backstop in the form of a freewheel on the pump or motor shaft. The occurring despite the return lock volumetric losses are undesirable and represent a significant loss of energy.

The object of the invention is to provide a pump arrangement by which the disadvantages described are to be avoided. In addition, the use of complex and therefore more expensive components should be avoided.

This object is achieved according to the invention by a diffuser arranged in an interior of the housing and a valve device arranged in the interior of the housing, an opening of the diffuser being designed as a valve seat for a valve body of the valve device.

By using a valve device whose valve body cooperates with the diffuser as a valve seat, can be dispensed with a complex and expensive backstop. Since a back flow into the pump housing and thus the reverse rotation is prevented by the valve device, the volumetric losses are completely avoided in the still running pump.

Advantageously, the valve device comprises a valve cage, a valve spring arranged in the valve cage, and a valve body arranged displaceably in the valve cage and acted upon by the valve spring with a spring force. This allows a simple-to-produce check valve, which is easily pre-assembled

For an undisturbed flow flow, the valve device is arranged opposite the opening of the diffuser in a cup-like region of the housing. Thus, in the opened state of the valve device, the flow path can be fully released. In order that the valve device can be placed reliably, the housing advantageously has a base body which has a step formed by a reinforcement of the wall of the body inwardly into the interior stage, wherein the valve cage has a ring collar extending in the radial direction, which at the Level of the body comes to rest.

According to one embodiment of the invention, at least one axial bore is formed in the annular collar of the valve basket, in which at least one tube is inserted, which extends into a recess in the ring of the diffuser. About axial bore, tube and recess takes place at each switching operation of the valve device, a pressure compensation. As a result, an additional to the flow pulse force is applied to the valve piston by the pressure difference between the inlet and the downstream side of the pump, which keeps the valve device open during operation of the pump. In a further embodiment, the valve cage has a bottom, which is connected via a guide wall with the annular collar. The valve body in turn has a sealing surface facing the diffuser and an annular wall extending from the sealing surface towards the bottom of the valve basket, whereby on the one hand tilting of the valve body and on the other hand low-friction switching of the valve device is possible.

In a further advantageous embodiment, the valve body is mushroom-shaped or stepped, wherein the sealing surface extends radially beyond the annular wall. Due to the mushroom-like or step-shaped design of the valve body, depending on the respective diameter over an annular differential surface, which is produced by the supernatant, a dependent of the pressure difference, which is generated by the pumps in operation, dependent additional closing force are applied at a further favorable Further, the Ventiikorb a through hole in the ground, through which extends a guide rod. In the valve body is while a blind hole provided, into which projects the guide rod for reliable guidance of the valve body.

Another object of the invention is to provide a nuclear reactor with improved efficiency

The nuclear reactor has to solve the problem on a pump assembly according to the invention.

Further features and advantages of the invention will become apparent from the description of some embodiments with reference to drawings and from the drawings themselves.

Showing:

FIG. 1 shows a schematic representation of a nuclear reactor with pump arrangements arranged thereon according to the invention,

Figure 2 shows the longitudinal section through a first embodiment of an inventive

Pump arrangement with pump part, connecting element and motor part,

3 shows a longitudinal section through the pump part of FIG. 2 with a closed

Valve,

Figure 4 shows a longitudinal section through the pump part of Fig. 2 with an open

Valve,

Figure 5 shows the longitudinal section through the pump part of a second embodiment with an open valve, and

6 shows the longitudinal section through the pump part of a third embodiment with an open valve, Fig. 1 shows a reactor 1, to which over the outer circumference preferably evenly distributed pump assemblies according to the invention 2 are mounted for conveying heated in the reactor transfer liquid. FIG. 2 shows an exemplary embodiment of the pump arrangement 2 according to the invention. The pump arrangement 2 has a pump part 3 and a motor part 4, which are coupled to one another by means of a connecting element 5.

In the motor part 4, an unillustrated drive, usually a flowed through by a cooling medium electric motor or canned electric motor accommodated. Its output shaft 6 extends through the connecting element 5 in the pump part 3. Optionally, a flywheel may be arranged on the output shaft 6 within the connecting element 5, which temporarily maintains the conveying activity in case of failure of the drive.

As shown in more detail in FIG. 3, the pump part 3 comprises a housing 7 with hydraulic parts arranged therein in more detail below. The housing 7 has a substantially cylindrical base body 8 with a central longitudinal axis X, which coincides with the axis of rotation of the output shaft 6. The main body 8 is closed at the side facing away from the engine by means of a curved bottom 9. The bottom 9 of the housing 7 is formed by a substantially spherical portion-shaped dome region 10 and a transition region between the base body 8 and dome region 10 forming rim region 11. On the side opposite the base 9, the housing 7 is closed by a cover element 12, wherein a central opening 13 is provided in the cover element 12, through which the output shaft 6 extends into an interior 14 of the housing 7.

The main body 8 is provided on the side opposite the bottom 9 with an annular connecting device 15 which projects in the axial direction and forms a step 16 on the end face of the main body 8. By means not shown threaded holes in the Anschiussvorrichtung 15 and screws or threaded rods of the main body 8 with the engine part 4 and the connecting element 5 shown in FIG connectable. The cover element 12 is attached to the connecting element 5 shown in Fig. 2 and is in the assembled state of the step 16 and separates the hydraulic flow space, so the interior 14 in the pump housing 7 of the overlying connecting element 5 from. The extent of the lid element 12 in the axial direction substantially corresponds to the axial extent of the connection device 15. Sealing elements, not shown, ensure the necessary tightness of the components.

By means of one or more holding devices 12a connected to the lid member 12, projects a fluid guide device 17 from above into the interior 14 and thereby at least partially surrounds the output shaft 6 and an impeller attached thereto 18. Preferably, the holding devices 12a, the lid member 12 and the fluid guide device 17th formed in one piece. A diffuser 19 is attached to the free end of the fluid guiding device 17 projecting downwardly into the inner space 14 and extends further down into the inner space 14. The junction of the fluid guiding device 17 and the diffuser 19 is stepped to center the diffuser 19.

In the diffuser 9, for a guide vanes 20 are provided for guiding the transmitter liquid, on the other hand, a bearing receptacle 21 is realized in the interior of the diffuser 19, which is held by the Leitradschaufeln 20 concentrically in the diffuser 19. Additionally or alternatively, the bearing receptacle 2 can be held concentrically in the diffuser 19 by means of ribs 22. In the bearing seat 21, a radial bearing 23 is provided, which supports the end of the output shaft 6. In order to prevent an accumulation of particles, an opening 24 is provided at the lower, the impeller 18 remote from the end of the bearing seat 21.

The fluid guide device 17 facing away from the end of the diffuser 19 has an opening 25 and is provided with a ring extending in the radial direction 26 which rests as far as possible on the inside of the body 8 and by means not shown Dichtiemente the interior 14 in a formed above the ring 26 Ring- raum 27 with an inflow region 28 and an underlying Abstömbereich 29 shares.

The main body 8 of the housing 7 is provided on a side wall with a fastening stub 30, which is pressure-tight connected to the reactor jacket. Within the attachment socket 30, the horizontal inflow and outflow of the pump assembly takes place. In this case, the attachment piece 30 is similar to a double-walled tube. The attachment piece 30 has a passage 31 through which fluid to be delivered can flow via an inflow opening 32 into the inflow region 28 or via an outflow opening 33 out of the outflow region 29.

Between the outflow region 29 and the dome region 10, the interior 14 has a pot-shaped region 34, in which a valve device 35 is arranged in the form of a check valve. The valve device 35 comprises a valve basket 36, a valve spring 37 and a piston-like valve body 38. The valve spring 37 is supported on the valve cage 36 and urges the valve body 38 with a spring force in the direction of the diffuser 19. Below the outflow region 29, the main body 8 has via a step 39, which arises by reinforcing the wall of the main body 8 inwards into the interior 14. The Venti [basket 36 has on the side facing away from the Kalottenbereich 10 of the pump housing 7 on a radially extending annular collar 40 which comes to the stage 39 of the base body 8 to the plant. Screws that are not shown extend through bores, likewise not shown, formed in the annular collar 40, which are screwed into threaded holes (not visible) in the step 39 and connect the valve cage 36 to the base body 8 of the housing 7.

The valve cage 36, which is arranged concentrically with respect to the longitudinal axis X, has a bottom 41 facing the dome area 0, which is connected to the annular collar 40 via a guide wall 42

At least one bore 43 extends in the axial direction through the valve basket 36. In the present embodiment, at least two holes 43 extend through the bottom 41. In the center of the bottom 41, a disk-like projection 44 projecting into the interior of the valve basket 36 for holding and guiding the valve spring 37 is provided. In the annular collar 40 at least one parallel to the central longitudinal axis X extending axial bore 45 is formed. In the at least one axial bore 45, a tube 46 is inserted, which extends upward in an aligned to the at least one axial bore 45 Ausnehm 47 in the arranged at the free end of the diffuser 19 ring 26 and the inflow region 28 with the region 34 of the interior 14 connects. The pot-shaped valve body 38 has a sealing surface 48 facing the diffuser 19 and an annular wall 49 extending from the sealing surface 48 in the direction of the bottom 41. The sealing surface 48 has a curvature pointing in the direction of the diffuser 19. By means of the annular wall 49, the valve body 38 is axially movably arranged in the valve basket 36 along the guide wall 42 feasible. Inside, at the bottom 41 facing side, the valve body 38 has a disc-like projection 50 for holding and guiding the valve spring 37. The edge of the opening 25 in the diffuser 19 forms the valve seat for the valve body 38.

Fig. 3 shows the Pumpengteil 3 during the regular operation of the Pumpenanord- tion 2. The carrier liquid flows, caused by rotation of the output shaft 6 and thus the impeller 18 in the inflow region 28. From there, the horizontally directed inflow is deflected and vertically upward directed and promoted by the base body 8, diffuser 19, fluid guide device 17 formed annular space 27. From the annular space 27, the fluid flows to the cover element 12 formed as a manifold on the side facing the interior 14 and is deflected from there radially symmetrically downward into the interior of the fluid guiding device 7 to the impeller 18. Under increased pressure, the fluid flows through a further annular space 51, which is defined in the interior of the diffuser 19 through the bearing receptacle 22 and the wall of the diffuser 9, in the outflow region 29. In this, the deflection of the flow takes place in a horizontal direction and the fluid then flows via the discharge opening to the reactor. The valve body 38 is completely inserted into the valve basket 36 and thereby completely releases the flow path. The valve body 38 forms to the flow leading areas of the annular collar 40 no paragraph or step. The sealing surface 48 also represents a flow-guiding contour. With this arrangement, the opened valve device 35 causes no flow resistance. 4 shows the pump part 3 at standstill of the pump assembly 2. After the impeller 18 promotes no more fluid, the valve body 38 acting on the force of the valve spring 37 is greater than the pressure force of the standing above the valve body 38 water column. As a result, the valve body 38 is pressed against the valve seat formed by the edge of the opening 25 in the diffuser 19. At the same time, fluid can flow from the annular space 27 through the tube 46 and the at least one bore 43 in the bottom 41 into the interior of the valve body 38 and valve cage 36 and support the closing movement of the valve body 38.

When the pump assembly 2 goes back into operation, the fluid is again pressed by the impeller 18 against the valve body 38, whereby this, as shown in FIG. 3, is moved into the valve basket 36. At the same time, the fluid can flow out of the interior of the valve body 38 and the valve cage 36 to depressurize the underside of the valve body 38. wherein a suction effect is established by the fluid flowing in the direction of the cover element 12, which promotes the flow of fluid through the tube 46 and thus the insertion of the valve body 38 into the valve cage 36.

In the embodiment shown in FIG. 5 with a simplified bearing support element 21, the cover element 12 has an area with a greater radial extent than in the case of the figures shown and described above. The axial extent of the connection device 15 is less than in the embodiment in FIG. 3. A region of the cover element 12 extends beyond the connection device 15 of the main body 8. The valve body 38 of the embodiment shown in FIG. 5 is mushroom-shaped or stepped. The sealing surface 48 extends radially beyond the annular wall 49 also. In the region of the annular collar 40, an axial recess 52 is provided, into which the radially projecting sealing surface 48 is received when the valve body 36 is pushed into the valve cage 36. Due to the mushroom-like or step-shaped design of the valve body 38 can depend on In the embodiment shown in FIG. 6, a first sub-region 53 of the cover element 12 is located on the one side of the differential diameter D, depending on the pressure difference generated by the pumps in operation Level 16 on. In the radial direction, a part 54 of the connecting element 5 shown in FIG. 1 is arranged between the partial region 53 and the connecting device 15 of the housing 7. A second partial region 55 of the cover element 12 extends at least partially into the interior 14 of the housing 7 itself, that each variant of the cover element 12 shown with correspondingly adapted dimensions can be used on all cases 7 shown.

The valve basket 36 has in the bottom 41 via a concentric to the Mitteilängsachse X arranged through hole 56, which is designed as a stepped bore. The through hole 56 has a portion 57 with a reduced inner diameter and a portion 58 with an enlarged inner diameter. Through the throughbore 56 extends a guide rod 59 which is connected over a reduced outer diameter portion 60 associated with the reduced inner diameter portion 57 and over an enlarged outer diameter portion 61 associated with the enlarged inner diameter portion 58 , features. The free end of the guide rod 59 extending in the direction of the dome area 10 of the housing 7 is provided with a thread onto which a nut 62 can be screwed. Thereby, in the axial direction, the enlarged outer diameter portion 61 of the guide rod 59 is pressed against the portion 57 of the through hole 56 having the reduced inner diameter, and the guide rod 59 is securely held.

The bottom 41 has on the side opposite the nut 62 a trough-like region 63 in which the valve spring 37 is arranged. The at least one bore 43 extends in the radial direction through the valve basket 36. In the present embodiment, the at least one bore 43 extends through the guide In a variant of the embodiment shown in FIG. 6, not shown, the at least one bore 43 in the axial direction, as shown, inter alia, in Fig. 3, or in an oblique direction through the bottom 41 of the valve basket 36th extend.

The valve body 38 is formed mushroom-like, wherein extending in the direction of the bottom 41 projection 50 extends in the closed state of the valve device 35 to the trough-like region 63. The projection 50 has a conically extending portion 64 and a cylindrical portion 65. In the valve body 38, in particular in the projection 50, a blind hole 66 is provided, into which the guide rod 59 protrudes, whereby the valve body 38 can be safely guided in its Axiaibewegung.

When the pump assembly 2 is in operation, the fluid flows into the inflow region 28, from there through the annular space 27, then through the manifold formed in the cover element 12 into the annular space 51 of the interior of the diffuser 19 through the bearing seat 21 and the Wall of the diffuser 19 is formed, and finally in the outflow region 29. The valve body 38 is thereby completely pressed by the pulse of the flow in the valve basket 36. Meanwhile, the fluid initially present in the interior of the valve device 35 escapes through the at least one bore 43 and the at least one axial bore 45 into the outflow region 29 and then, together with the fluid present in the outflow region 29, out of the pump housing 7 via the outflow opening 33 led out. At standstill of the impeller 18, the valve body 38 is urged by the valve spring 37 in the direction of the diffuser 19 against the valve seat formed by the edge of the opening 25. In this case, fluid can flow from the outflow region 29 through at least one axial bore 45 required for pressure equalization and the at least one bore 43 into the interior of the valve device 35.

Claims

1. pump arrangement

(2) for mounting to a nuclear reactor and for delivering transfer liquid heated in the reactor, comprising a motor part (4) and a pump part having a housing (7)

(3), characterized by a in an interior (14) of the housing (7) arranged diffuser (19) and in the interior (14) of the housing (7) arranged valve device (35), wherein an opening (25) of the diffuser (19) is designed as a valve seat for a valve body (38) of the valve device (35). 2. Pump arrangement according to claim 1, characterized in that the valve device (35) a valve cage (36), one in the valve cage (36) arranged valve spring (37) and one in the valve cage (36) slidably disposed by the valve spring (37 3). Pump arrangement according to claim 1 or 2, characterized in that the

Valve device (35) opposite the opening (25) of the diffuser (19) in a pot-like region (34) of the housing (7) is arranged.

4. Pump arrangement according to one of claims 1 to 3, characterized in that the housing (7) has a base body (8), which via a through a

Reinforcement of the wall of the base body (8) inwardly into the interior (14) resulting step (39) has, and that the valve cage (36) in a radial Rieh- tion extending annular collar (40) which comes to the step (39) of the base body (8) for conditioning.

5. Pump arrangement according to one of claims 2 or 4, characterized in that in the annular collar (40) of the valve basket (36) at least one axial bore (45) is formed, in which at least one tube (46) is inserted, which is in a recess (47) in a at the free end of the diffuser (19) arranged ring (26) extends.

6. Pump arrangement according to one of claims 2 to 5, characterized in that the valve cage (36) has a bottom (41) which is connected via a guide wall (42) with the annular collar 39.

7. Pump arrangement according to one of claims 2 to 6, characterized in that the Ventiikörper (38) via a the diffuser (19) facing the sealing surface (48) and from the sealing surface (48) towards the bottom (41) of the valve basket ( 36) extending annular wall (49) has.

8. Pump arrangement according to one of claims 2 to 7, characterized in that the valve body (38) is mushroom-shaped or stepped, wherein the sealing surface (48) extends radially beyond the annular wall (49) addition.

9. Pump arrangement according to claim 8, characterized in that the valve cage (38) has a through-bore (56) in the bottom (41), through which a guide rod (59) extends, and in that the valve body (38) has a blind hole (66). is provided, in which the guide rod (59) for guiding the valve body (38) protrudes. lO. Nuclear reactor (1) characterized by a pump arrangement (2) according to one of claims 1 to 10