EP0065922B1 - Pompe primaire d'un réacteur nucléaire à eau sous pression comportant un dispositif d'étanchéité de son arbre d'entrainement - Google Patents

Pompe primaire d'un réacteur nucléaire à eau sous pression comportant un dispositif d'étanchéité de son arbre d'entrainement Download PDF

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Publication number
EP0065922B1
EP0065922B1 EP82400929A EP82400929A EP0065922B1 EP 0065922 B1 EP0065922 B1 EP 0065922B1 EP 82400929 A EP82400929 A EP 82400929A EP 82400929 A EP82400929 A EP 82400929A EP 0065922 B1 EP0065922 B1 EP 0065922B1
Authority
EP
European Patent Office
Prior art keywords
seal
chamber
shaft
pressure
upstream
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82400929A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0065922A1 (fr
Inventor
Nicolaas Bonhomme
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Areva NP SAS
Original Assignee
Framatome SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Framatome SA filed Critical Framatome SA
Publication of EP0065922A1 publication Critical patent/EP0065922A1/fr
Application granted granted Critical
Publication of EP0065922B1 publication Critical patent/EP0065922B1/fr
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/10—Shaft sealings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/10—Shaft sealings
    • F04D29/106—Shaft sealings especially adapted for liquid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D13/00—Pumping installations or systems
    • F04D13/02—Units comprising pumps and their driving means
    • F04D13/06—Units comprising pumps and their driving means the pump being electrically driven

Definitions

  • the invention relates to a primary pump of a pressurized water nuclear reactor comprising a device for sealing its drive shaft.
  • the cooling circuit of the reactor core, or primary circuit comprises at least two cooling loops each comprising a steam generator and a primary pump.
  • the primary pumps consist of a volute inside which rotates an impeller rigidly attached to the lower end of a drive shaft connected to a motor.
  • Sealing along the drive shaft is ensured by a set of seals arranged in an annular space between the shaft and a housing which surrounds this shaft from its exit from the volute to the drive motor.
  • the sealing device of the drive shaft of the primary pumps generally consists of three seals comprising a fixed part secured to the housing and a mobile part secured to the shaft.
  • the facing surfaces of these sealing elements are either in rubbing contact, the seal is then of the mechanical type, or separated by a layer of fluid in circulation between the surfaces of the seal, the seal is then of the hydrostatic type.
  • the water circulated by the pump is at a very high pressure, of the order of 150 bars.
  • the seal placed most upstream on the drive shaft, that is to say closest to the internal part of the pump, is therefore a hydrostatic seal which allows a significant pressure drop between its upstream part and its downstream part, while the seals arranged downstream are generally mechanical type seals.
  • a high pressure cold water supply circuit makes it possible to bring into the annular space limited by the housing, upstream of the hydrostatic seal, water, part of which is discharged towards the volute of the pump and of which another part supplies the hydrostatic seal leakage current. After passing through the hydrostatic seal, this water is also used to cool the mechanical seals.
  • a pump for a high pressure fluid such as the primary water of a pressurized water nuclear reactor and its drive motor
  • the pump drive shaft is placed in a cylindrical housing which provides an annular space around the shaft receiving the pressurized fluid.
  • a hydrostatic seal is arranged between the drive shaft and the housing, at the end through which the drive shaft exits, in order to prevent leaks of high pressure fluid towards the outside and in particular towards the engine. Coolant of the hydrostatic seal at a pressure slightly higher than the pressure of the fluid circulated by the pump is introduced into the annular space, upstream of the hydrostatic seal, that is to say in the part of the annular space located towards the pump.
  • a hydrostatic seal as used on primary pumps as an upstream seal has for example been described in patents FR-A-1,435,568 and FR-A-2,049,690.
  • this pressure limit is of the order of 14 bars.
  • the cooling water of the reactor is at a pressure of the order of 150 bars and the cold water injected upstream of the hydrostatic seal is at a slightly higher pressure, so that the pressure drop across the hydrostatic seal is very high and generally around 150 bars. The proper functioning of the hydrostatic seal is then ensured.
  • the injection pressure upstream of the hydrostatic seal is no longer sufficient to ensure such a ⁇ P greater than 14 bars and the hydrostatic seal can no longer function correctly.
  • the object of the invention is therefore to propose a primary pump for a pressurized water nuclear reactor comprising a drive shaft, a housing surrounding this shaft so as to provide an annular space around the shaft and a device for '' seal made up of a set of seals placed one after the other along the length of the shaft in the annular space, at least one of which, disposed most upstream, that is to say say towards the inside of the pump, is of the hydrostatic type with liquid leakage between two elements limiting this leakage, one connected to the shaft and the other to the housing, the part of the annular space which is located upstream of the seal and which constitutes a chamber in communication with the internal part of the pump being supplied with water at a pressure higher than the primary pressure of the reactor by a circuit, this primary pump being able to remain in operation even if the pressure of the fluid which is carried out the pumping reaches low values, for example the lower than 26 bars.
  • FIG. 1 we see a pump comprising a pump body or volute 1 pierced with a suction opening 2 and a delivery opening 3.
  • a diffuser 4 Inside this volute is arranged a diffuser 4 inside which rotates the impeller 5 secured to the drive shaft 7 connected to the drive motor of the pump not shown.
  • the upper part of the pump body has a coupling flange 8 making it possible to connect the pump to its motor unit.
  • the shaft 7 is surrounded by a housing 9 which provides an annular space 10 around it.
  • the housing 9 includes a flange 12 for connection to the pump drive motor.
  • seals 14 making it possible to seal along the shaft 7.
  • the shaft 7 carries at its end entering the volute the impeller 5 and exits from this volute at a labyrinth seal 16 at which is also placed a thermal barrier 17 traversed by a cooling coil.
  • the shaft 7 then passes through a bearing 15 ensuring its maintenance and its guidance.
  • the seal 14 disposed most upstream, that is to say towards the inside of the pump, and therefore placed closest to the bearing 15, is of the hydrostatic type, cold water under a pressure slightly higher than the water pressure in the pump being injected by injection pipes 19, into the annular space 10 in which the seals are placed.
  • FIG. 2 we see a schematic representation of the sealing device associated with a primary pump of the same type as the pump shown in FIG. 1.
  • the impeller 25 integral with the end of the shaft 27 is rotated by means of this tree.
  • the shaft passes through a set of two labyrinth seals 26 themselves surrounded by the thermal barrier 28 traversed by a coil 29 supplied with cooling water.
  • the shaft 27 then passes through the annular space 30 delimited by a housing arranged around the shaft along its entire length until it is connected to the drive motor 31.
  • the first seal 33 disposed upstream is of the hydrostatic type with liquid leakage between its rotating part linked to the shaft 27 and its fixed part linked to the housing.
  • the seals 34 and 35 are of the mechanical type comprising two floating parts, one of which is integral with the shaft and the other of the housing.
  • a cold pressurized water supply circuit 36 makes it possible to bring this cold water to a pressure slightly higher than the pressure of the water circulated by the pump, in the annular space 30, upstream of the seal 33.
  • the pressure of this cold water is adjusted by means of a bypass valve 38 and a charge pump 39 placed in bypass on the main line of the circuit 36.
  • a pressure gauge 40 makes it possible to check the pressure in the circuit 36. Lines 41, 42 and 43 make it possible to recycle the water recovered downstream of the seal 33 in the supply circuit 36.
  • the sealing device according to the invention further comprises an auxiliary seal 45 disposed upstream of the hydrostatic seal 33 in the part of the annular space 30 constituting a chamber 46 in communication with the internal part of the volute 21, by means of the labyrinth seals 26.
  • the auxiliary seal 45 is a mechanical seal with rubbing surfaces which separates the chamber 46 into two parts, 46a situated upstream of the seal 45 and 46b situated downstream of the seal 45 and upstream of the seal 33.
  • a pipe 47 makes it possible to join the two parts 46a and 46b of the chamber 46.
  • a valve 48 is arranged on the pipe 47 to isolate or put the two parts of the chamber 46 into communication.
  • a valve 49 is placed in bypass with respect to the valve 48.
  • the auxiliary seal 45 consists of a fixed part 50 secured to the housing 29 and a movable part 51 secured to the shaft 27, the surfaces of which are placed in facing contact are in rubbing contact.
  • the hydrostatic seal 33 consists of a floating lining and a rotating lining separated by a film of water with controlled leakage.
  • the thickness of the water film (water filtered and injected upstream of the seal 33 in the chamber 46b by the circuit 36) is regulated by the geometric profile of the active parts as a function of the pressure in the chamber 46b.
  • the water leak from this seal 33 is partly evacuated through the seal 34 and the rest towards the circuit 36 via the pipe 41 (FIG. 2).
  • the nuclear reactor During normal operation of the pump, the nuclear reactor being in service, it causes the circulation of the water in the primary circuit which is at a pressure of the order of 150 bars and at a temperature above 300 ° C.
  • the valve 48 disposed on the pipe 47 connecting the two parts of the chamber 46 is open. Cold water is brought by the circuit 36 in the part 46b of the chamber, at a pressure slightly higher than the pressure of the primary circuit.
  • the placing in communication of the two parts 46a and 46b of the chamber 46 by the pipe 47 produces a pressure balancing between these two parts of the chamber, so that the pressure difference across the auxiliary seal 45 is negligible. It is therefore possible to provide a rubbing contact between the surfaces facing the seal 45, with a low application pressure so that the wear of this seal is very limited.
  • the seal 45 is cooled by the water of the circuit 36 and works at moderate temperature.
  • the sealing device then operates like the devices of the prior art, the pressure difference across the hydrostatic seal 33 being practically equal to the overpressure of the primary circuit.
  • the pressure in the primary circuit can drop to a low value, for example less than 26 bars.
  • this pressure will be chosen equal to 26 bars so as to be just above the minimum threshold of ⁇ p allowing the operation of the seal 33.
  • the pressure difference between the chamber 46b subjected to a pressure close to 26 bars and the chamber 46a subjected to a pressure close to that of the primary circuit is at most equal to 26 bars, so that the pressure drop of on either side of the joint 45 is at most equal to this value.
  • the seals with rubbing surfaces of the sealing device shown in FIGS. 2 and 3 operate in good conditions because the pressure drops on either side of these seals are weak and the circulation of water coming from in contact with these seals allows lubrication of the friction surfaces.
  • the seal 45 is cooled and lubricated by the water injected by the circuit 36 while the seals 34 and 35 are cooled and lubricated by a part of the water passing through the seal 33. This water allowing the cooling and the lubrication is finally recycled by lines 41, 42 and 43.
  • valve 49 placed in bypass with respect to the valve 48 is designed to remain closed as long as the pressure in the chamber 46a is lower than the pressure in the chamber 46b.
  • This valve opens only in the case of an overpressure in the chamber 46a relative to the chamber 46b. During normal operation of the reactor, this valve therefore remains closed since the circuit 36 introduces water at slight overpressure relative to the water in the primary circuit.
  • the pressure in the chamber 46a becomes higher at the pressure in the chamber 46b which is no longer supplied and the valve 49 opens, so that the water of the primary circuit cooled by the thermal barrier 28 can penetrate into the chamber 46b and perform the cooling and lubrication of seals with rubbing surfaces to replace the cold water injected by circuit 36.
  • an advantage of the device according to the invention is to allow the operation of the primary pumps of a nuclear reactor at low pressure. During the reactor shutdown phases it becomes possible to continue circulating the water in the primary circuit without using auxiliary means to maintain its pressure above 26 bars.
  • the reactor cooling circuit which makes it possible to lower the temperature and the pressure of the primary circuit during the cold shutdown phases of the reactor can be used at pressures below 26 bars, which was not the case. not possible previously since circulation of primary water must be maintained during the shutdown phases.
  • this cooling circuit can be used until the final phases of the cold shutdown of the reactor.
  • the hydrostatic seal disposed upstream of the sealing device can be associated with seals of any type and the number of these seals is not limited.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP82400929A 1981-05-21 1982-05-19 Pompe primaire d'un réacteur nucléaire à eau sous pression comportant un dispositif d'étanchéité de son arbre d'entrainement Expired EP0065922B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8110128A FR2506399A1 (fr) 1981-05-21 1981-05-21 Dispositif d'etancheite de l'arbre d'entrainement d'une pompe pour fluide a haute pression
FR8110128 1981-05-21

Publications (2)

Publication Number Publication Date
EP0065922A1 EP0065922A1 (fr) 1982-12-01
EP0065922B1 true EP0065922B1 (fr) 1985-07-17

Family

ID=9258727

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82400929A Expired EP0065922B1 (fr) 1981-05-21 1982-05-19 Pompe primaire d'un réacteur nucléaire à eau sous pression comportant un dispositif d'étanchéité de son arbre d'entrainement

Country Status (12)

Country Link
US (1) US4587076A (es)
EP (1) EP0065922B1 (es)
JP (1) JPS57198395A (es)
KR (1) KR880001267B1 (es)
CA (1) CA1193482A (es)
DE (1) DE3264764D1 (es)
EG (1) EG15240A (es)
ES (1) ES512345A0 (es)
FI (1) FI71394C (es)
FR (1) FR2506399A1 (es)
YU (1) YU96682A (es)
ZA (1) ZA823471B (es)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5076757A (en) * 1981-01-29 1991-12-31 Vaughan Co., Inc. High head centrifugal slicing slurry pump
DE3680606D1 (de) * 1985-08-09 1991-09-05 Dolphin Machinery Loetapparat.
US4722663A (en) * 1986-02-04 1988-02-02 Rotoflow Corporation Seal-off mechanism for rotating turbine shaft
GB9008987D0 (en) * 1990-04-21 1990-06-20 David Brown Corp Limited Means for applying a back pressure to a shaft seal
FR2821978B1 (fr) * 2001-03-12 2003-06-20 Jeumont Sa Procede de reparation du joint labyrinthe d'un diffuseur d'une pompe primaire d'une centrale nucleaire
US6599091B2 (en) * 2001-05-29 2003-07-29 James Nagle Modular submersible pump
US20020181325A1 (en) * 2001-06-05 2002-12-05 Engel David J Mixer seal and bearing apparatus and method
FI20050451A (fi) * 2005-04-29 2006-10-30 Sulzer Pumpen Ag Keskipakopumpun sivulevyn kiinnityksen tiivistysjärjestely ja siinä käytettävä kiinnitysruuvi
CN101403395B (zh) * 2008-11-17 2011-01-12 浙江大农实业有限公司 高压水泵之调压机构
DE102013004908B3 (de) * 2013-03-22 2014-02-06 Ksb Aktiengesellschaft Ventil und Pumpenanordnung mit Ventil
US10107126B2 (en) * 2015-08-19 2018-10-23 United Technologies Corporation Non-contact seal assembly for rotational equipment

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3215083A (en) * 1963-10-23 1965-11-02 Westinghouse Electric Corp Dynamoelectric machinery for use in high pressure fluid systems
US3347552A (en) * 1964-06-04 1967-10-17 Westinghouse Electric Corp Controlled leakage face type seals
DE1800254B2 (de) * 1968-01-24 1971-09-30 Vorrichtung zur sicherstellung der kuehlung der wellen abdichtungen und mediumgeschmierten radiallager von unter hohen systemdruecken arbeitenden umwaelzpumpen
AT279747B (de) * 1968-07-30 1970-03-10 Andritz Ag Maschf Anlage zum Reinigen der Kühlflüssigkeit von Kernreaktoren
US3632117A (en) * 1969-05-15 1972-01-04 Westinghouse Electric Corp Seal lift-off mechanism
US3620639A (en) * 1969-08-22 1971-11-16 Karl Gaffal Pump with hydrostatic bearing
JPS4934211B1 (es) * 1970-12-16 1974-09-12
JPS4929221B1 (es) * 1970-12-16 1974-08-02
US3652179A (en) * 1971-03-10 1972-03-28 Westinghouse Electric Corp Controlled leakage centrifugal pump
US4189156A (en) * 1978-06-08 1980-02-19 Carrier Corporation Seal system for a turbomachine employing working fluid in its liquid phase as the sealing fluid

Also Published As

Publication number Publication date
ZA823471B (en) 1983-03-30
EG15240A (en) 1987-04-30
US4587076A (en) 1986-05-06
ES8406654A1 (es) 1984-07-01
FI71394B (fi) 1986-09-09
FI71394C (fi) 1986-12-19
FR2506399B1 (es) 1983-10-07
KR880001267B1 (ko) 1988-07-16
EP0065922A1 (fr) 1982-12-01
ES512345A0 (es) 1984-07-01
JPH0361039B2 (es) 1991-09-18
CA1193482A (fr) 1985-09-17
JPS57198395A (en) 1982-12-04
FR2506399A1 (fr) 1982-11-26
FI821802A0 (fi) 1982-05-20
YU96682A (en) 1986-08-31
DE3264764D1 (en) 1985-08-22
KR830010308A (ko) 1983-12-30

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