Sealed motor pump and nuclear reactor comprising such a pump

Abstract

The invention relates to a sealed motor pump comprising: - a bowl (3) having a fluid inlet (5) and a fluid outlet (7); - a pump wheel (9) arranged inside the bowl (3); - a motor housing (11) rigidly attached to the bowl (3) and internally defining a chamber (13) in fluid communication with the bowl (3); - a motor (15) comprising a rotor (17) and a stator (19), the motor being arranged inside the chamber (13); - a shaft (21) to which the pump wheel (9) is attached, the shaft (21) being driven in rotation around an axis of rotation by the rotor (17); - a heat exchanger (41) arranged inside the chamber (13), the heat exchanger having a first side (43) through which a fluid flows and a second side (45) through which a heat transfer fluid flows; - a circuit (47) for cooling the motor by means of a fluid, wherein a cooling channel (49) through which the fluid flows is in thermal contact with the motor (15), and wherein the first side (43) of the heat exchanger (41) forms part of the cooling circuit (47) and is arranged downstream of the cooling channel (49).

Description

Technical Field

[0001] This invention generally relates to sealed motor pumps. Background Technology

[0002] SMR (Small Modular Reactor) nuclear reactors can be equipped with a primary sealed motor pump designed to circulate primary fluids within the reactor vessel.

[0003] When such primary pumps are located at the bottom of a nuclear reactor, specific constraints regarding the maximum authorized flow rate in the event of a leak must be observed.

[0004] In particular, for pipes used for primary fluid circulation, there must be no fragile pipes with a diameter greater than 4 mm in the pump.

[0005] In a primary sealed motor pump, the heat released by the electric motor and the mechanical losses due to the rotation of parts in water are removed by the circulation of a primary fluid within the outer housing that houses the motor. This primary fluid itself must be cooled by circulation in a heat exchanger, where the heated primary fluid comes into contact with the heat transfer fluid.

[0006] In this type of primary pump, a heat exchanger can be arranged around an outer casing. In this case, the circulation side of the primary fluid in the heat exchanger is connected to the outer casing via pipes with an inner diameter of approximately 20 mm. These pipes are welded to the pump's outer casing and are therefore classified as fragile components.

[0007] Therefore, this arrangement does not comply with the safety constraints that must be followed for primary pumps located in the lower part of a nuclear reactor.

[0008] In this context, the present invention aims to provide a pump that does not have the aforementioned drawbacks. Summary of the Invention

[0009] Therefore, the present invention relates to a sealed motor pump for fluids, comprising:

[0010] - A bowl-shaped component having a fluid inlet and a fluid outlet;

[0011] - Pump impeller, which is arranged inside the cup-shaped member;

[0012] - A motor housing, which is integrated with the bowl-shaped component and internally defines a chamber in fluid communication with the bowl-shaped component;

[0013] - A motor, comprising a rotor and a stator, the motor being arranged inside the chamber;

[0014] - A shaft, on which the pump wheel is fixed, the shaft being driven by the rotor to rotate about a rotation axis;

[0015] - A heat exchanger arranged inside the chamber, the heat exchanger having a first side in which a fluid circulates and a second side in which a heat transfer fluid circulates;

[0016] - A motor cooling circuit through which the fluid has a cooling channel, the fluid circulates along the cooling channel in thermal contact with the motor, the first side of the heat exchanger forming part of the cooling circuit and arranged downstream of the cooling channel.

[0017] Because the heat exchanger is arranged inside a chamber defined by the motor housing, there are no pipes outside the motor housing for fluid circulation between the exchanger and the chamber. The circulation of the fluid used to cool the motor occurs entirely within the motor housing, which is a non-fragile component. Therefore, the constraint on the maximum leakage flow rate is satisfied.

[0018] Hermetically sealed motor pumps may also have one or more of the following characteristics, either individually or in combination of all technically possible features:

[0019] - The motor housing includes a cylindrical wall surrounding the motor, and the heat exchanger is radially arranged between the motor and the cylindrical wall;

[0020] - The heat exchanger includes a cylindrical membrane having a proximal end axially facing the pump impeller and a distal end axially opposite the pump impeller, the cylindrical membrane having an external channel on a radially outer surface for the heat transfer fluid and an internal channel on a radially inner surface for the fluid;

[0021] - The external channel includes at least one external spiral groove formed by hollowing out the radial external surface, and / or the internal channel includes at least one internal spiral groove formed by hollowing out the radial internal surface;

[0022] - The proximal and distal ends of the cylindrical membrane are welded to the inner surface of the motor housing to fluidly isolate the external channel from the internal channel;

[0023] - The pump includes a stator housing having a cylindrical metal sleeve that is radially inserted between the radial inner surface of the cylindrical diaphragm and the stator, and seals the internal channel on the radial inner side;

[0024] - The stator housing includes a proximal support ring and a distal support ring, which are axially arranged on both sides of the motor and rigidly fixed to the two opposite ends of the metal sleeve. The edge surfaces of the proximal support ring and the distal support ring are pressed against the radial inner surface of the cylindrical diaphragm at the horizontal level of the proximal end and the horizontal level of the distal end, respectively.

[0025] - The one or each of the outer spiral grooves has a first outer depth at the axial central portion of the cylindrical membrane, and has a second outer depth less than the first outer depth at the horizontal level of the proximal end and the horizontal level of the distal end of the cylindrical membrane; and / or

[0026] The one or each inner spiral groove has a first internal depth at the axial central portion of the cylindrical membrane, and has a second internal depth less than the first internal depth at the level of the proximal end and the level of the distal end of the cylindrical membrane.

[0027] - A distal volume is defined between the distal support ring and the distal bottom of the motor housing, the distal support ring including a plurality of openings at its periphery that allow the distal volume to be in fluid communication with the internal channel;

[0028] - The pump includes a component for circulating the fluid along the motor cooling circuit, the component being integrated with the shaft and housed in the distal volume;

[0029] - The pump includes:

[0030] - A proximal bearing having a proximal retaining ring mounted on the proximal support ring and a proximal rotating ring integrated with the shaft;

[0031] - A distal bearing having a distal retaining ring mounted on the distal support ring and a distal rotating ring integrated with the shaft.

[0032] The cooling channel includes a proximal volume axially located between the proximal support ring and the proximal bottom of the motor housing, a proximal intermediate volume axially located between the proximal bearing and the rotor, a gap between the rotor and the stator, a distal intermediate volume located between the rotor and the distal bearing, and the distal volume.

[0033] - The proximal fixed ring and / or the proximal rotating ring include a channel for the fluid to circulate from the proximal volume to the proximal intermediate volume, and the distal fixed ring and / or the distal rotating ring include a channel for the fluid to circulate from the distal intermediate volume to the distal volume;

[0034] - The pump includes a heat transfer fluid inlet and a heat transfer fluid outlet fluidly connected to the second side of the heat exchanger, the heat transfer fluid inlet being intended to be connected to a heat transfer fluid supply line and the heat transfer fluid outlet being intended to be connected to a heat transfer fluid discharge line, the pump including an inlet shut-off member and / or an outlet shut-off member, the inlet shut-off member being configured to selectively isolate or connect the heat transfer fluid inlet and the heat transfer fluid supply line, and the outlet shut-off member being configured to selectively isolate or connect the heat transfer fluid outlet and the heat transfer fluid discharge line.

[0035] According to a second aspect, the present invention relates to a nuclear reactor comprising:

[0036] - The reactor core, which includes nuclear fuel assemblies;

[0037] - A pressure vessel that houses the reactor core, the pressure vessel being filled to a nominal level with primary heat transfer fluid;

[0038] - At least one primary pump having the above-described features, arranged to circulate the primary heat transfer fluid in the reactor core, the primary pump being installed at a level below or equal to the nominal level.

[0039] Nuclear reactors may also have one or more of the following characteristics, either individually or in combination of all technically possible features:

[0040] - The primary pump is mounted on the pressure vessel, the cylindrical wall is placed outside the pressure vessel, and the pump impeller is placed inside the pressure vessel. Attached Figure Description

[0041] Other features and advantages of the invention will become apparent from the following detailed description of the invention, given by way of indication rather than limitation, with reference to the accompanying drawings, in which:

[0042] - Figure 1 This is an axial cross-sectional view of the sealed motor pump of the present invention;

[0043] - Figure 2 and Figure 3 yes Figure 1 Enlarged views of details II and III;

[0044] - Figure 4 yes Figure 1 An exploded perspective view of a sealed motor pump; and

[0045] - Figure 5 It is equipped with a basis Figures 1 to 4 A schematic diagram of the axial cross-section of the primary pump of a nuclear reactor. Detailed Implementation

[0046] Figure 1 The sealed motor pump is designed to move fluid.

[0047] In one exemplary embodiment, the sealed motor pump is designed to circulate the primary fluid of an SMR nuclear reactor.

[0048] The primary fluid circulates within the pressure vessel, in which the reactor core is located, via a sealed motor pump 1. The primary fluid passes through the reactor core, then through the steam generator, and finally reaches the suction side of the sealed motor pump 1. The sealed motor pump 1 discharges the primary fluid into the reactor pressure vessel.

[0049] A sealed motor pump is placed, for example, in the lower part of a nuclear reactor, that is, at the same level as or lower than the pressure vessel of the nuclear reactor. For example, it is installed below the nominal level of the primary fluid in the pressure vessel.

[0050] Seal-mounted motor pumps are used alternatively to circulate primary fluids that are not nuclear reactors. According to another alternative, they are used in nuclear reactors of a different type than SMR reactors, or in any other industrial facility that is not a nuclear reactor.

[0051] like Figure 1 As seen, the sealed motor pump 1 includes a bowl-shaped member 3 having a fluid inlet 5 and a fluid outlet 7, and a pump impeller 9 arranged inside the bowl-shaped member 3. The fluid inlet constitutes the pump's suction port, and the fluid outlet 7 corresponds to the pump's discharge port.

[0052] The sealed motor pump 1 is advantageously centrifugal, with the fluid inlet 5 being axial and the fluid outlet 7 being radial.

[0053] Pump 1 also includes a motor housing 11, which is integrated with the bowl-shaped member 3 and internally defines a chamber 13 that is in fluid communication with the bowl-shaped member 3.

[0054] The sealed motor pump 1 also includes a motor 15 having a rotor 17 and a stator 19 arranged inside the chamber 13.

[0055] The sealed motor pump 1 also includes a shaft 21, on which the pump wheel 9 is fixed. The shaft 21 is driven by the rotor 17 to rotate around the rotation axis X.

[0056] The pump wheel 9 is rigidly fixed to the proximal end 23 of the shaft 21.

[0057] The proximal end 23 protrudes axially to the outside of the motor housing 11 and is housed inside the bowl-shaped member 3.

[0058] The rotor 17 is directly fixed to the shaft 21.

[0059] The stator 19 is arranged around the rotor 17, and the gap 25 separates the stator and the rotor.

[0060] The rotor 17 and stator 19 are cylindrical in shape and are coaxial with the rotation axis X.

[0061] The motor housing 11 is designed to bear the weight of the motor 15 and transfer that weight to the structure supporting the motor. It has rigidity suitable for these functions.

[0062] The motor housing 11 directly defines the internal volume that houses the motor 15, the shaft 21, and the bearings that support the shaft 21. The internal volume corresponds to the chamber 13.

[0063] The motor housing 11 includes a cylindrical wall 27 surrounding the motor 15. The cylindrical wall is cylindrical and coaxial with the axis X.

[0064] The motor housing 11 also includes a distal bottom 29 that liquid-tightly seals the distal end of the cylindrical wall 27. This distal end corresponds to the end axially opposite to the pump impeller 9.

[0065] The motor housing 11 includes an extension 31 that extends the cylindrical wall 27 axially toward the pump impeller 9. The extension 31 includes a flange 33 for fastening to the proximal end of the cylindrical wall 27. The extension 31 is tubular and coaxial with the axis X.

[0066] The motor housing 11 also includes a proximal bottom 35 that axially closes the extension 31 toward the pump wheel 9.

[0067] The bowl-shaped member 3 is integrated with the proximal bottom 35. The shaft 21 exits the chamber 13 through an opening 37 formed at the center of the proximal bottom 35. The chamber 13 is in fluid communication with the bowl-shaped member 3 through the opening 37. Fluid can circulate between the interior of the bowl-shaped member 3 and the interior of the chamber 13 along the shaft 21.

[0068] The pressure inside the bowl-shaped part 3 is basically equal to the pressure inside the chamber 13.

[0069] A thermal barrier 39 is arranged in the chamber 13 along the portion of the adjacent opening 37 of the axis 21. The thermal barrier 39 occupies the end of the extension 31.

[0070] The sealed motor pump 1 also includes a heat exchanger 41 arranged inside the chamber 13, the heat exchanger 41 having a first side 43 in which fluid circulates and a second side 45 in which heat transfer fluid circulates.

[0071] The fluid circulating on the first side 43 and the heat transfer fluid circulating on the second side 45 come into thermal contact with each other through the wall of the exchanger 41.

[0072] The sealed motor pump 1 also includes a motor cooling circuit 47 through which fluid flows, the motor cooling circuit 47 having a cooling channel 49, and the fluid circulates along the cooling channel 49 in thermal contact with the motor 15.

[0073] The first side 43 of the heat exchanger forms part of the motor cooling circuit 47 and is located downstream of the cooling channel 49.

[0074] The motor cooling circuit 47 is completely housed inside the chamber 13, that is, inside the motor housing 11.

[0075] The fluid circulating along the motor cooling circuit 47 rotates in a closed loop inside the motor housing 11 without flowing outside the housing.

[0076] The heat exchanger 41 is arranged radially between the motor 15 and the cylindrical wall 27.

[0077] More specifically, the heat exchanger 41 includes a cylindrical membrane 51 having an external channel for heat transfer fluid on a radially outer surface 53 and an internal channel for fluid on a radially inner surface 55.

[0078] The cylindrical membrane 51 is coaxial with the axis X. It is made of a metal heat trap, such as stainless steel.

[0079] It has a proximal end 57 that points axially toward the pump wheel 9 and a distal end 59 that is axially opposite to the pump wheel 9.

[0080] The internal channels form the first side 43 of the heat exchanger. The external channels form the second side 45 of the heat exchanger.

[0081] The external channel includes at least one external spiral groove 61 formed by hollowing out the radial outer surface 53 of the cylindrical membrane.

[0082] Typically, it includes a plurality of external spiral grooves 61 arranged parallel to each other in the radial outer surface 53. In the example shown, the outer channel includes twelve external spiral grooves 61.

[0083] One or each of the outer spiral grooves 61 is wound around the axis X and extends from the proximal end 57 to the distal end 59 along the entire axial length of the cylindrical membrane 51.

[0084] In the same manner, the internal channel includes at least one internal spiral groove 63 formed by hollowing out in the radial internal surface 55.

[0085] Preferably, the internal channel includes a plurality of internal spiral grooves 63 arranged parallel to each other. In the example shown, the internal channel includes twelve internal spiral grooves 63.

[0086] One or each inner spiral groove 63 is wound around axis X and extends from the proximal end 57 to the distal end 59 along the entire axial length of the cylindrical membrane 51.

[0087] One or each of the outer spiral grooves 61 has a first outer depth at the axial central portion of the cylindrical membrane 51, and a second outer depth less than the first outer depth at the level of the proximal end 57 and the level of the distal end 59.

[0088] The first depth is greater than 50% of the thickness of the cylindrical film 51, and preferably greater than 75% of the thickness of the cylindrical film.

[0089] At the proximal and distal ends of the cylindrical membrane, the depth of the outer spiral groove 61 gradually decreases. Therefore, the last turn of the outer spiral groove 61 is very shallow, the penultimate turn is slightly deeper, and so on.

[0090] In the same manner, the inner spiral groove 63 has a first internal depth at the axial center portion of the cylindrical membrane 51, and a second internal depth less than the first internal depth at the level of the proximal end 57 and the distal end 59 of the cylindrical membrane 51.

[0091] like Figure 2 and Figure 3 As can be seen, the first internal depth is greater than 50% of the thickness of the cylindrical film 51, and preferably greater than 75% of the thickness of the cylindrical film 51.

[0092] The inner spiral groove 63 has a gradually decreasing depth at the level of the proximal end 57 and at the level of the distal end 59.

[0093] like Figure 3 As can be seen, at the level of the distal end 59, the last turn of the inner spiral groove 63 has a very small depth. The penultimate turn has a slightly larger depth, and so on.

[0094] At the proximal end 57, the depth of the inner spiral groove 63 decreases only slightly, and remains at the level of the last turn, for example, greater than 50% of the thickness of the cylindrical film 51. Figure 2 ).

[0095] Therefore, in its central portion, the cylindrical membrane 51, considered in a cross-section within the plane containing the axis X, has a tortuous shape with a constant wall thickness. Each turn of the inner spiral groove 63 is framed by two turns belonging to the outer spiral groove 61 (see...). Figure 2 and Figure 3 This allows for an excellent heat exchange coefficient between the fluid and the heat transfer fluid in the heat exchanger.

[0096] The proximal end 57 and distal end 59 of the cylindrical diaphragm 51 are welded to the inner surface of the motor housing 11 to fluidly isolate the external channel from the internal channel.

[0097] More precisely, and as Figure 2 As shown, a lip 65 is formed on the radially outer surface 53 of the cylindrical membrane 51. This lip 65 is welded to a complementary lip 67 formed on the inner surface of the housing 11 by an invisible weld. The two lips 65 and 67 are substantially cylindrical, with the lip 67 positioned radially around the lip 65.

[0098] At the distal end 59, a lip 69 is formed on the radially inner surface 55 of the cylindrical membrane 51. It is welded to a complementary lip 73 formed on the inner surface of the housing via a weld 71. Lips 69 and 73 are substantially annular. Lip 73 is axially adjacent to lip 69.

[0099] Pump 1 also includes a stator housing 75 having a cylindrical metal sleeve 77 that is radially inserted between the radially inner surface 55 of the cylindrical diaphragm 51 and the stator 19.

[0100] The metal sleeve 77 is made of a material with good electrical and thermal conductivity, such as stainless steel.

[0101] The central portion of the cylindrical membrane 51 corresponds to the portion of the cylindrical membrane 51 that is pressed against the sleeve 77. It covers at least 70% of the axial length of the cylindrical membrane, preferably at least 80% of the axial length of the cylindrical membrane.

[0102] The stator housing 75 also includes a proximal support ring 79 and a distal support ring 81, which are axially arranged on both sides of the motor 15 and rigidly fixed to the two opposite axial ends of the metal sleeve 77.

[0103] The edge face of the proximal support ring 79 is pressed against the radial inner surface 55 of the cylindrical membrane 51 at the level of the proximal end 57. In the same manner, the edge face of the distal support ring 81 is pressed against the radial inner surface 55 of the cylindrical membrane 51 at the level of the distal end 59.

[0104] Therefore, the edge surfaces of the support rings 79 and 81 are pressed against one or more of the inner spiral grooves 63 of the radial inner surface 55, which have a smaller depth. Consequently, these areas have higher mechanical strength than the central portion.

[0105] The stator housing 75 also includes two enclosing plates 83 disposed on the radially inner edges of the proximal support ring 79 and the distal support ring 81. The plates 83 enclose the volume between the ring 79 and the stator 19 and the volume between the stator 19 and the ring 81 on one radially inner side.

[0106] The stator winding 84 is housed in these volumes and is isolated from the fluid by the enclosing plate 83, support rings 79 and 81, and metal sleeve 77.

[0107] Especially in Figure 3 As can be seen, a distal volume 85 is defined between the distal support ring 81 and the distal bottom 29 of the motor housing 11.

[0108] Figure 4 The distal support ring 81 is shown to include a plurality of openings 87 at its periphery, which allow the distal volume 85 to be in fluid communication with the internal channel.

[0109] Openings 87 are distributed around the periphery of the distal support ring 81. They are formed by hollowing out the edge surface of the ring 81 (i.e., on the radially outer surface). They are axially open at one end to provide access to the distal volume 85. They are axially closed at the opposite ends. They are radially outward to communicate with one or more inner helical grooves 63.

[0110] Pump 1 also includes a component 89 for circulating fluid along motor cooling circuit 47.

[0111] The component 89 is integrated with the shaft 21 and housed in the distal volume 85. Therefore, it is driven to rotate together with the shaft 21.

[0112] In the example shown, component 89 is a disk with a plurality of radial holes 90R that open at the level of the radial outer edge face of the disk.

[0113] Component 89 also includes a plurality of axial holes 90A, each axial hole 90A opening at its two ends at the level of two opposing large faces of the disk. Each radial hole 90R leads into one of the axial holes 90A at its inner end opposite the radial outer edge face of the disk.

[0114] Therefore, component 89 performs a pumping function in the motor cooling circuit. The radial orifice can produce a pumping effect by applying kinetic energy to the fluid. The axial orifice is used to supply fluid to the radial orifice.

[0115] As a variation and / or additionally, component 89 includes blades of the type used in centrifugal pumps, for example, to improve hydraulic efficiency.

[0116] The circulation component 89 drives the fluid radially outward until it reaches the opening 87.

[0117] like Figure 1 As can be seen, pump 1 also includes:

[0118] - Proximal bearing 91, which has a proximal retaining ring 93 mounted on a proximal support ring 79 and a proximal rotating ring 95 integrated with the shaft 21;

[0119] - The distal bearing 97 has a distal retaining ring 99 mounted on the distal support ring 81 and a distal rotating ring 101 integrated with the shaft 21.

[0120] Motor 15 is axially located between two bearings.

[0121] The cooling channel 49 includes a proximal volume 103 axially located between the proximal support ring 79 and the proximal bottom 35 of the motor housing 11, a proximal intermediate volume 105 axially located between the proximal bearing 91 and the rotor 17, a gap 25 between the rotor and the stator, and a distal intermediate volume 107 located between the rotor 17 and the distal bearing 97. The cooling channel 49 also includes a distal volume 85.

[0122] The proximal volume 103 is axially defined on one side by the proximal support ring 79 and the proximal bearing 91. It is axially defined relative to the thermal barrier 39. It is located inside the extension 31.

[0123] To allow circulation between volumes 103 and 105, the proximal fixed ring 93 and / or the proximal rotating ring 95 include a channel 109 for fluid to circulate from the proximal volume 103 to the proximal intermediate volume 105.

[0124] In the same manner, the distal fixed ring 99 and / or the distal rotating ring 101 include a channel 111 for fluid to circulate from the distal intermediate volume 107 to the distal volume 85.

[0125] Pump 1 also includes a heat transfer fluid inlet 113 and a heat transfer fluid outlet 115 that are fluidly connected to a second side 45 of heat exchanger 41. Inlet 113 and outlet 115 are formed, for example, in motor housing 11.

[0126] Pump 1 also includes an inlet manifold 117 and an outlet manifold 119, which are respectively fluidly connected to inlet 113 and outlet 115.

[0127] The inlet manifold 117 is a groove formed by hollowing out the inner surface of the cylindrical wall 27. It is located opposite the proximal end 57 of the cylindrical membrane 51. The outlet manifold 119 is a groove formed by hollowing out the inner surface of the cylindrical wall 27. It is located opposite the distal end 59 of the cylindrical membrane 51.

[0128] Alternatively, the inlet manifold is on the distal side of the cylindrical membrane, and the outlet manifold is on the proximal side.

[0129] The radial outer surface 53 of the cylindrical membrane 51 is pressed against the inner surface of the cylindrical wall 27. Therefore, one or each of the outer spiral grooves 61 opens at one end to the inlet groove 117. One or each of the outer spiral grooves 61 opens at its opposite end to the outlet groove 119.

[0130] Except at the level of grooves 117 and 119, the radially inner surface of cylindrical wall 27 closes the external channel on a radially outer surface.

[0131] Sleeve 77, in itself, closes the internal channel on one radially inward side.

[0132] More precisely, it seals off the central part of the internal passageway.

[0133] The edge surfaces of the proximal support ring 79 and the distal support ring 81 partially enclose the internal channel at the level of the proximal end 57 and the distal end 59 of the cylindrical membrane, respectively. At the level of the proximal end 57, the internal channel communicates with the proximal volume 103, and the last turn of one or each inner spiral groove 63 extends beyond the proximal support ring 79 and is therefore not covered by the edge surface of that ring.

[0134] The heat transfer fluid inlet 113 is intended to be connected to the heat transfer fluid supply pipe 121. The heat transfer fluid outlet 115 is intended to be connected to the heat transfer fluid discharge pipe 123.

[0135] The pump also includes an inlet shut-off member 125 and / or an outlet shut-off member 127, the inlet shut-off member 125 being configured to selectively isolate or connect the heat transfer fluid inlet 113 and the heat transfer fluid supply line 121, and the outlet shut-off member 127 being configured to selectively isolate or connect the heat transfer fluid outlet 115 and the heat transfer fluid discharge line 123.

[0136] The inlet shut-off component 125 is, for example, an on / off valve.

[0137] The outlet shut-off component 127 is, for example, an on / off valve.

[0138] The operation of the pump described above will now be described in detail.

[0139] When the pump is running, the chamber 13 defined by the motor housing is filled with fluid. The latter is in pressure equilibrium with the internal volume of the bowl-shaped part 3.

[0140] When rotor 17 drives pump wheel 9 to rotate, the circulating component 89 also rotates. This causes fluid to circulate within chamber 13 along motor cooling circuit 47.

[0141] The fluid flows from the proximal volume 103 through the channel 109 and also between the rings 93 and 95 to the proximal intermediate volume 105 in the cooling channel 49.

[0142] Fluid flows from the proximal intermediate volume 105 along the gap 25 to the distal intermediate volume 107. In doing so, it cools the rotor 17 and the stator 19.

[0143] Fluid flows from the distal intermediate volume 107 through channel 111 and between rings 99 and 101 to the distal volume 85.

[0144] Within the distal volume 85, fluid flows in the channels of the circulation member 89 and is propelled to the opening 87.

[0145] The fluid then enters the internal passage of the heat exchanger 41, specifically the first side 43 of the heat exchanger. It flows from the distal end 59 to the proximal end 57 of the cylindrical membrane 51 along one or more internal spiral channels 63.

[0146] After reaching the proximal end 57 of the cylindrical membrane, it returns to the proximal volume 103.

[0147] During its passage through one or more inner spiral channels 63, the fluid comes into thermal contact with both the sleeve 77 and the heat transfer fluid flowing on the second side 45 of the heat exchanger 41.

[0148] The heat transfer fluid enters the pump through inlet 113 and is directed to inlet recess 117. It circulates from inlet recess 117 in the external channel, and more precisely along one or more external spiral channels 61. It is collected in outlet recess 119 and flows from there to fluid outlet 115.

[0149] Figure 5 The nuclear reactor 129 shown includes:

[0150] - Core 131, which includes nuclear fuel assemblies;

[0151] - Pressure vessel 133, which houses the reactor core 131, is filled to the nominal level with primary heat transfer fluid;

[0152] - At least one primary pump 135, which is arranged to circulate the primary heat transfer fluid in the core 131.

[0153] Nuclear reactor 129 is an integrated type. For example, it is an SMR.

[0154] It includes a steam generator 137 housed in a pressure vessel 133.

[0155] The reactor core 131 is placed in the lower part of the pressure vessel 133. The steam generator 137 is housed above the reactor core 131.

[0156] The nuclear reactor 129 also includes a pressurizer 139 defined inside the container cover 141.

[0157] One or each of the primary pumps 135 is arranged to circulate the primary heat transfer fluid in a loop within the pressure vessel 133. The primary heat transfer fluid passes through the reactor core 131, then circulates through the steam generator 137, and is then returned to the reactor core 131 by one or each of the primary pumps 135.

[0158] In the example shown, the nuclear reactor includes several primary pumps 135, such as six primary pumps.

[0159] One or each primary pump 135 is a sealed motor pump of the type described above.

[0160] One or each primary pump 135 is installed at a level below or equal to the nominal level of the primary heat transfer fluid in pressure vessel 133.

[0161] The nominal level of the primary heat transfer fluid in pressure vessel 133 corresponds substantially to the level of the contact plane between the flange and the cover 141 of the pressure vessel.

[0162] One or each primary pump 135 is preferably installed vertically between the reactor core 131 and the steam generator 137. The vertical direction substantially corresponds to the axis of the pressure vessel 133.

[0163] One or each primary pump 135 is mounted on pressure vessel 133, cylindrical wall 27 is placed outside pressure vessel 133, and pump wheel 9 is placed inside pressure vessel 133.

[0164] One or each primary pump 135 is mounted with its axis of rotation horizontal, which is typically radial relative to the central axis of the pressure vessel.

[0165] A radially external fastening flange 143 is formed at the proximal end of the cylindrical wall 27. It is directly fixed to the pressure vessel 133. The extension 31 engages in an opening formed in the pressure vessel 133.

[0166] The pump described above has several advantages.

[0167] Arranging the heat exchanger radially between the cylindrical wall of the motor and the motor housing allows for easy housing of the heat exchanger within the motor housing. This arrangement provides a large contact surface between the fluid and the heat transfer fluid.

[0168] When a heat exchanger comprises a cylindrical membrane having an external channel on the radially outer surface for the heat transfer fluid and an internal channel on the radially inner surface for the fluid, heat exchange between the fluid and the heat transfer fluid occurs through the cylindrical membrane. This is particularly convenient for housing the heat exchanger within the motor housing and organizing fluid circulation without excessively increasing the overall size of the pump.

[0169] When the outer channel includes at least one outer spiral groove formed by hollowing out in the radial outer surface and / or the inner channel includes at least one inner spiral groove formed by hollowing out in the radial inner surface, the outer and inner channels are produced in a particularly compact manner, and the heat exchange between the two channels is particularly good.

[0170] Welding a cylindrical diaphragm to the inner surface of the motor housing at both ends allows for easy fluid isolation between the external and internal channels.

[0171] When the pump includes a stator housing having a cylindrical metal sleeve that is radially inserted between the radially inner surface of a cylindrical diaphragm and the stator and has an internal channel closed on one radially inner side, the heat released by the stator is directly transferred by conduction to the fluid circulating in the internal channel. This optimizes the cooling of the stator.

[0172] Since the stator housing includes a proximal support ring and a distal support ring arranged axially on both sides of the motor, the proximal support ring and the distal support ring are rigidly fixed to the two opposite ends of the metal sleeve. The edge surfaces of the proximal support ring and the distal support ring are pressed against the radial inner surface of the cylindrical diaphragm at the horizontal level of the proximal end and the horizontal level of the distal end, respectively, so the diaphragm is held in place by the support rings.

[0173] When the outer spiral groove has a first outer depth at the axial center portion of the cylindrical membrane and a second outer depth less than the first outer depth at the horizontal level of the proximal end and the horizontal level of the distal end of the cylindrical membrane, the cylindrical membrane has higher mechanical resistance at the horizontal level of its two ends and can withstand the pressure applied by the support ring.

[0174] Similarly, when the inner spiral groove has a first internal depth at the axial center portion of the cylindrical membrane and a second internal depth less than the first internal depth at the horizontal level of the proximal end and the horizontal level of the distal end of the cylindrical membrane, the membrane has higher mechanical resistance at the horizontal level of its two ends and can withstand the pressure applied by the support ring.

[0175] When the distal support ring has multiple openings around its periphery that allow fluid communication between the distal volume and the internal channel, the communication between the distal volume and the internal channel is made in a simple and convenient manner.

[0176] When the pump includes components integrated with the shaft and housed in the distal volume for circulating fluid along the cooling circuit, the circulation of fluid along the motor cooling circuit is particularly simple.

[0177] When the proximal bearing includes a proximal stationary ring and / or a proximal rotating ring with channels for fluid circulation, fluid circulation along the cooling channels is facilitated. Similarly, when the distal bearing includes a distal stationary ring and / or a distal rotating ring with channels for fluid circulation, fluid circulation along the cooling channels is facilitated.

[0178] When the pump includes an inlet shut-off member configured to selectively isolate or connect the heat transfer fluid inlet and the heat transfer fluid supply line and / or an outlet shut-off member configured to selectively isolate or connect the heat transfer fluid outlet and the heat transfer fluid discharge line, the gap can be isolated from the heat transfer fluid supply line and / or the heat transfer fluid discharge line in the event of a heat exchanger rupture. The shut-off member is designed to withstand the pressure of the primary fluid.

[0179] Pumps can have many variations.

[0180] The pump does not have to be centrifugal; it can be any suitable type.

[0181] The fluid inlet to the bowl-shaped part is not necessarily axial, and the fluid outlet is not necessarily radial.

[0182] The bowl-shaped part can be directly attached to the cylindrical wall of the motor housing without being inserted into the extension.

[0183] The rotor is not necessarily mounted directly on the shaft; the shaft can be driven by the rotor, for example, through a reduction gear.

[0184] External channels can include any other suitable non-spiral grooves: straight, tortuous, etc.

[0185] External channels can be created in ways other than by hollowing out one or more grooves in the cylindrical membrane. For example, one or more grooves can be hollowed out in the inner surface of the cylindrical wall. Ribs defining the fluid circulation channels between them can be welded to the outer surface of the cylindrical membrane.

[0186] In the same way, internal channels can include any other suitable non-spiral grooves: straight, tortuous, etc.

[0187] Internal channels can be created in ways other than by hollowing out one or more grooves in the cylindrical membrane. For example, one or more grooves can be hollowed out in the outer surface of the stator sleeve. Ribs defining the fluid circulation channels between them can be welded to the inner surface of the cylindrical membrane.

[0188] The heat exchanger can also be manufactured in the form of a cylindrical film of greater thickness, which includes axially drilled holes. Fluid circulates in one part of the axially drilled holes, and the heat transfer fluid circulates in another part of the axially drilled holes.

Claims

1. A sealed motor pump for fluids, comprising: - A bowl-shaped component (3) having a fluid inlet (5) and a fluid outlet (7); - Pump wheel (9), which is arranged inside the cup-shaped part (3); - Motor housing (11), which is integrated with the bowl-shaped member (3) and internally defines a chamber (13) in fluid communication with the bowl-shaped member (3). - A motor (15) comprising a rotor (17) and a stator (19) disposed inside the chamber (13); - Shaft (21), the pump wheel (9) is fixed on the shaft (21), the shaft (21) is driven by the rotor (17) to rotate about the axis of rotation; - A heat exchanger (41) arranged inside the chamber (13) has a first side (43) in which a fluid circulates and a second side (45) in which a heat transfer fluid circulates. - A motor cooling circuit (47) for cooling the motor by means of the fluid has a cooling channel (49) along which the fluid circulates in thermal contact with the motor (15), and the first side (43) of the heat exchanger (41) forms part of the cooling circuit (47) and is arranged downstream of the cooling channel (49).

2. The pump according to claim 1, wherein the motor housing (11) includes a cylindrical wall (27) placed around the motor (15), and the heat exchanger (41) is radially arranged between the motor (15) and the cylindrical wall (27).

3. The pump according to claim 2, wherein the heat exchanger (41) comprises a cylindrical membrane (51) having a proximal end (57) axially toward the pump impeller (9) and a distal end (59) axially opposite to the pump impeller (9), the cylindrical membrane (51) having an external channel for the heat transfer fluid on a radially outer surface (53) and an internal channel for the fluid on a radially inner surface (55).

4. The pump according to claim 3, wherein the outer channel includes at least one outer spiral groove (61) formed by hollowing out in the radial outer surface (53), and / or the inner channel includes at least one inner spiral groove (63) formed by hollowing out in the radial inner surface (55).

5. The pump according to claim 3 or 4, wherein the proximal end (57) and the distal end (59) of the cylindrical diaphragm (51) are welded to the inner surface of the motor housing (11) to fluidly isolate the external channel from the internal channel.

6. The pump according to any one of claims 3 to 5, wherein the pump (1) comprises a stator housing (75) having a cylindrical metal sleeve (77) that is radially inserted between the radial inner surface (55) of the cylindrical membrane (51) and the stator (19) and closes the internal passage on the radial inner side.

7. The pump according to claim 6, wherein the stator housing (75) includes a proximal support ring (79) and a distal support ring (81), the proximal support ring (79) and the distal support ring (81) being axially arranged on both sides of the motor (15) and rigidly fixed to the two opposite ends of the metal sleeve (77), the edge surfaces of the proximal support ring (79) and the edge surfaces of the distal support ring (81) being pressed against the radial inner surface (55) of the cylindrical diaphragm (51) at the level of the proximal end (57) and the level of the distal end (59), respectively.

8. The pump according to claim 7 in conjunction with claim 4, wherein one or each of the outer helical grooves (61) has a first outer depth at the axial central portion of the cylindrical diaphragm (51), and has a second outer depth less than the first outer depth at the level of the proximal end (57) and the distal end (59) of the cylindrical diaphragm (51); and / or One or each inner spiral groove (63) has a first internal depth at the axial center portion of the cylindrical membrane (51) and a second internal depth less than the first internal depth at the level of the proximal end (57) and the level of the distal end (59) of the cylindrical membrane (51).

9. The pump according to claim 7 or 8, wherein a distal volume (85) is defined between the distal support ring (81) and the distal bottom (29) of the motor housing (11), the distal support ring (81) including a plurality of openings (87) at its periphery, the plurality of openings (87) allowing the distal volume (81) to be in fluid communication with the internal passage.

10. The pump of claim 9, wherein the pump (1) includes a component (89) for circulating the fluid along the motor cooling circuit (47), the component being integrated with the shaft (21) and housed in the distal volume (85).

11. The pump according to any one of claims 7 to 10, wherein the pump (1) comprises: - Proximal bearing (91) having a proximal retaining ring (93) mounted on the proximal support ring (79) and a proximal rotating ring (95) integrated with the shaft (21). - A distal bearing (97) having a distal retaining ring (99) mounted on the distal support ring (81) and a distal rotating ring (101) integrated with the shaft (21). The cooling channel (49) includes a proximal volume (103) axially located between the proximal support ring (79) and the proximal bottom (35) of the motor housing (9), a proximal intermediate volume (105) axially located between the proximal bearing (91) and the rotor (17), a gap (25) between the rotor (17) and the stator (19), a distal intermediate volume (107) located between the rotor (17) and the distal bearing (81), and the distal volume (85).

12. The pump of claim 11, wherein the proximal fixed ring (93) and / or the proximal rotating ring (95) includes a channel (109) for the fluid to circulate from the proximal volume (103) to the proximal intermediate volume (105), and the distal fixed ring (99) and / or the distal rotating ring (101) includes a channel (111) for the fluid to circulate from the distal intermediate volume (107) to the distal volume (85).

13. The pump according to any one of claims 1 to 12, wherein the pump comprises a heat transfer fluid inlet (113) and a heat transfer fluid outlet (115) fluidly connected to a second side (45) of the heat exchanger (41), the heat transfer fluid inlet (113) being intended to be connected to a heat transfer fluid supply line (121), the heat transfer fluid outlet (115) being intended to be connected to a heat transfer fluid discharge line (123), the pump comprising an inlet shut-off member (125) and / or an outlet shut-off member (127), the inlet shut-off member (125) being configured to selectively isolate or connect the heat transfer fluid inlet (113) and the heat transfer fluid supply line (121), and the outlet shut-off member (127) being configured to selectively isolate or connect the heat transfer fluid outlet (115) and the heat transfer fluid discharge line (123).

14. A nuclear reactor (129) comprising: - Core (131), which includes nuclear fuel assemblies; - A pressure vessel (133) that houses the reactor core (131), the pressure vessel (133) being filled to the nominal level with primary heat transfer fluid; - At least one primary pump (135) according to any one of claims 1 to 13, arranged to circulate the primary heat transfer fluid in the core (1), the primary pump (135) being installed at a level below or equal to the nominal level.

15. The nuclear reactor according to claim 14, wherein the primary pump (135) is mounted on the pressure vessel (133), the cylindrical wall (27) is placed outside the pressure vessel (33), and the pump wheel (9) is placed inside the pressure vessel (133).

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