EP0178545A1 - Générateur de vapeur - Google Patents

Générateur de vapeur Download PDF

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Publication number
EP0178545A1
EP0178545A1 EP85112524A EP85112524A EP0178545A1 EP 0178545 A1 EP0178545 A1 EP 0178545A1 EP 85112524 A EP85112524 A EP 85112524A EP 85112524 A EP85112524 A EP 85112524A EP 0178545 A1 EP0178545 A1 EP 0178545A1
Authority
EP
European Patent Office
Prior art keywords
inner shroud
pipe
barrel
steam generator
heating medium
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.)
Granted
Application number
EP85112524A
Other languages
German (de)
English (en)
Other versions
EP0178545B1 (fr
Inventor
Jun Kashiwakura
Hiroshi Tsuda
Kouji Abe
Yasuo Tachi
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP0178545A1 publication Critical patent/EP0178545A1/fr
Application granted granted Critical
Publication of EP0178545B1 publication Critical patent/EP0178545B1/fr
Expired legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/06—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being molten; Use of molten metal, e.g. zinc, as heat transfer medium
    • F22B1/063—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being molten; Use of molten metal, e.g. zinc, as heat transfer medium for metal cooled nuclear reactors

Definitions

  • the present invention relates a steam generator, and more particularly, to a steam generator which is suitable for employment in a liquid metal fast breeder reactor.
  • a conventional large scale herical coiling type steam generator in a liquid metal fast breeder reactor is known in, for example, Japanese Patent Laid-Open Publication No. 28467/1980.
  • High temperature liquid metal sodium serving as a heating medium flows into a longitudinal placement type steam generator through a sodium inlet nozzle provided at the upper end of a barrel of the steam generator.
  • the liquid metal sodium descends through a tube bundle portion around which is vertically and helically wound a multiplicity of heat transfer tubes.
  • This tube bundle portion is disposed in a region which is so formed as to be surrounded by a cylindrical inner shroud and an outer shroud. The thus lowered sodium then flows out through a sodium outlet nozzle.
  • Feed-water is supplied through a. feed-water inlet nozzle into a feed-water inlet chamber and is then led into a mulitiplicity of the heat transfer tubes, whereby the water is raised. At this time, the feed-water which has flowed in at low temperature is subjected to a thermal exchange with respect to the sodium which flows at high temperature on the outside of the heat transfer tubes.
  • the feed-water is preheated, boiled and superheated, thus vaporizing the feed-water at high temperature and at high pressure.
  • the thus produced vapor is collected in a vapor outlet chamber and then fed out from a vapor outlet nozzle to a turbine.
  • Fig. 3B shows a general example of a secondary sodium system loop of a fast breeder reactor which includes the above-described steam generators la and lb.
  • This system loop is constituted by an intermediate heat exchanger 23, the steam generators la and lb, a circulating pump 24 and pipes 31a, 32a and 33a.
  • the intermediate heat exchanger 23 performs the thermal exchange in regard to the primary sodium and the secondary sodium.
  • the steam generators la ; and lb produce vapor by effecting a thermal exchange between the feed-water and the secondary sodium with high temperature which is transmitted from the intermediate heat exchanger 23.
  • the circulating pump 24 circulates the secondary sodium.
  • a conventional steam generators shown in Fig. 3B are constituted by a superheater la and an evaporator lb which have the same structure with respect to each other.
  • the evaporator lb evaporates the feed-water by virtue of the heat evolved by the sodium; and the superheater la has a function to convert the vapor produced by the evaporator lb into the superheated vapor by further heating it with the sodium.
  • the secondary sodium which has been heated at high temperature by means of the intermediate heat exchanger 23 is transmitted via a hot leg pipe 31a, a middle leg pipe 32a and a cold leg pipe 33a to the superheater la or the evaporator lb.
  • the middle leg pipe 32a extended form the lower end of the superheater la passes through a floor (from the point f l to the point f 2 ) on which the superheater la is installed and is then descended. Furthermore, the middle leg pipe 32a reverses the piping direction thereof at the lower portion of the floor and again passes through the floor so as to reach the upper portion of the evaporator lb.
  • the cold leg pipe 33a extended from the lower end of the evaporator lb passes through the floor (from the point f 3 to the point f 4 ) on which the evaporator lb is installed and is then descended.
  • the sodium pipe is large in diameter; hence, it is required to avoid an increase in the length of a supporting skirt. For this reason, through-holes are formed in the floor, and further, a bent portion of the sodium pipe is provided beneath the floor such as to be led round.
  • the large through-holes are formed respectively in the floor on which the superheater la and the evaporator lb are installed. In such a case, elavorations are required so as to obtain the strength of the floor when designing the structure of the reinforced concrete or disposing the reinforcing bar as compared with an arrangement wherein no through-hole is formed therein.
  • the sodium within the longitudinal placement type steam generator of this publication papers flows into through the sodium inlet nozzle provided at the lower end of the barrel of the steam generator and is then raised within the inner shroud with which the sodium inlet nozzle is directly communicated, thereby reaching an upper sodium plenum chamber.
  • the sodium flows both inside and outside of the inner shroud, and there is a great difference in temperature between the inside flow and the outside flow thereof, whereby a great thermal stress is presumably imparted to the inner shroud.
  • the inner shroud Since the tube bundle portion is supported by the inner shroud, the inner shroud must be shielded from the thermal stress in so far as is possible.
  • the sodium pipe is provided on the lower side of the apparatus; hence, it is reasonable to assume that all the sodium within the steam generator would flow out if the pipe were seriously damaged, the flow mostly occurring in the damaged region.
  • An object of the present invention is to provide a steam generator wherein a difference in temperature about a region in the vicinity of an inner shroud can be reduced.
  • Another object of the present invention is to provide a steam generator wherein a thermal stress on an inner shroud can be reduced.
  • Still object of the present invention is to provide a steam generator wherein a compact piping structure can be obtained.
  • Stillmore object of the present invention is to provide a steam generator wherein a space required for disposing the pipes can be reduced.
  • Further object of the present invention is to provide a steam generator wherein an amount of leaked heating medium can be minimized.
  • object of the present invention is to provide a steam generator wherein no through-hole can be formed within the floor on which the steam generator is -J.nstalled.
  • the present invention is a steam generator comprising: a barrel having an inlet portion and an outlet portion for a heating medium; a multiplicity of heat transfer tubes being formed vertically in a helical configuration and being disposed in the barrel; an inner shroud formed a lower end opening being disposed such as to pass through the central portion of the helical heat transfer tubes and supporting the helical heat transfer tubes, the lower end opening being formed such as the heating medium flows into the inner shroud through the lower end opening; and an outer shroud being disposed on the outside of the helical heat transfer tubes and forming a passage for the heating medium between the inner shroud and the outer shroud; characterized in that both the inlet portion and the outlet portion for the heating medium are provided respectively at the upper portion of the barrel, an opening is formed in the upper end portion of the inner shroud so as to the heating medium flows out through said upper end opening of the inner shroud, and a region in the vicinity of the inner shroud is filled with a stagnant heating medium or an inert gas
  • the advantages offered by the present invention are a compact and secure steam generator which has effects wherein it is possible to reduce the difference in temperature about - a region in the vicinity of the inner shroud, the thermal stress on the inner shroud, the space for installing the steam generator as well as the amount of pipe, and to decrease the amount of leaked heating medium if the pipes are damaged and further to minimize the damage from a heating medium fire, should one occur.
  • Fig. 1 shows a steam generator 1 of a first embodiment according to the present invention.
  • a multiplicity of heat transfer tubes 2 pass through the lower portion of a cylindrical barrel 3, these heat transfer tubes 2 being communicated with feed-water inlet chambers 4.
  • the feed-water inlet chambers 4 are provided at the outside lower portion of the barrel 3 of the steam generator 1.
  • the heat transfer tubes 2 are vertically and helically wound around a cylindrical inner shroud 5 having an upper end opening 5a and a lower end opening 5b in the barrel 3, thereby forming a helically coiled tube bundle portion 6. These helical heat transfer tubes 2 further pass through the.' upper portion of the barrel 3 so as to be communicated with vapor outlet chambers 7.
  • a cylindrical outer shroud 8 is provided on the outside of the helically coiled tube bundle portion 6, such outer shroud 8 being designed for the purpose of shielding the heat and forming an offtake for sodium or heating medium.
  • a dual-purpose sodium inlet-outlet pipe or nozzle is provided at a single upper portion above the barrel 3.
  • a sodium outlet pipe or a sodium outlet nozzle 9 is coaxially provided within a sodium inlet pipe or a sodium inlet nozzle 10. Such sodium outlet pipe 9 passing through a bent portion 11 of the sodium inlet pipe 10 and further being connected to each other with the aid of a metal bellows 12 as a displacement absorption mechanism.
  • the sodium inlet pipe 10 includes an opening 13 which is so formed in an upper sodium plenum chamber 14 such as to be communicated therewith.
  • the sodium outlet pipe 9 extends downwardly and passes through the upper end opening 5a of the inner shroud 5.
  • Such sodium outlet pipe 9 includes another opening 15 which is formed in a lower sodium plenum chamber 16 such as to be communicated therewith.
  • the sodium outlet pipe 9 has a double pipe structure 18 with respect to the length ranging from the metal bellows 12 to the upper portion of the inner shroud 5.
  • An inert gas for medium as a thermal insulating material is encapsulated in a gap 17 formed between the inner pipe and the outer pipe of the double pipe structure 18.
  • a body supporting skirt 19 is provided at the lower portion of the barrel 3, the body supporting skirt 19 supporting the steam generator 1. No through-hole is provided in the concrete floor 20 on which the steam generator 1 is installed.
  • the steam generator 1 is the non-liquid level type, and thus the inside portion of the barrel 3 is filled with the sodium.
  • the initial method of filling the steam generator 1 with the sodium is usually on of two types: one is the pressurizing method wherein the pressurized sodium injected into the barrel 3 of the steam generator 1; and the other is the vacuum pull-in method wherein a high vacuum inside of the barrel 3 of the steam generator 1 pulles the sodium into the barrel 3.
  • the inner region of the inner shroud 5 and the similar region formed by the metal bellows 12 and the sodium outlet pipe 9 are each closed at one end thereof, thereby enclosing the fluid. It is also possible for the sodium to be filled in by the vacuum pull-in method. The above-described two regions are filled with stagnant or expended fluid regions by either method.
  • the high temperature sodium serving as a heating medium passes through a gap 21 formed between the sodium inlet pipe 10 and the sodium outlet pipe 9, both of which are provided on the upper side of the barrel 3.
  • Such high temperature sodium flows into the barrel 3 of the steam generator 1 and then descends through the helically coiled tube bundle portion 6 around which is helically wound with the helical heat transfer tubes 2.
  • the high temperature sodium reaches the lower sodium plenum chamber 16.
  • the high temperature sodium is subjected to the thermal exchange with respect to the water and the vapor within the helical heat transfer tubes 2.
  • Feed-water is supplied through a feed-water inlet pipe or nozzle into a feed-water inlet chamber 4 and is then led into a mulitiplicity of the helical heat transfer tubes 2, whereby the water is raised.
  • the feed-water which has flowed in at low temperature (about 240 o C with about 150 ata) is subjected to a thermal exchange with respect to the sodium which flow at high temperature (about 500°C with about 4 ⁇ 5 ata) on the outside of the helical heat transfer tubes 2.
  • the feed-water is preheated, boiled and superheated, thus vaporizing the feed-water at high temperature (about 487 0 C with high pressure about 33 ata). Then the sodium becomes at low temperature (about 320°C with about 4 ⁇ 5 ata). The thus produced vapor is collected in a vapor outlet chamber 7 and then fed out from a vapor outlet pipe or nozzle to a turbine.
  • the low temperature sodium (about 320°C with about 4 ⁇ 5 ata) which has reached the lower sodium plenum chamber 16 changes its flow direction and flows through the opening 13 of the sodium outlet pipe 9 into the sodium outlet pipe 9. Then, this low temperature sodium is raised and flows out from the steam generator 1.
  • the inner shroud 5 is joined to the barrel 3 and further to the sodium outlet pipe 9. Accordingly, the metal bellows 12 is provided on the sodium inlet pipe 10 in order to absorb the difference in the thermal expansion between the sodium outlet pipe 9 and the barrel 3.
  • the sodium inlet-outlet pipe or nozzle has a double structure for the purpose of obtaining a preferable sodium flux in the upper sodium plenum chamber 14 and a uniform sodium flux at the upper end portion of the helically coiled tube bundle portion 6.
  • the sodium inlet pipe 10 and the sodium outlet pipe 9 are concentrated at the upper portion of the barrel 3 respectively.
  • a bulkhead or patitioning plate 22 is provided in order to avoid the damage to the sodium inlet pipe 10 and the sodium outlet pipe 9 if the water-vapor system pipes rupture.
  • Fig. 2 shows a connecting arrangement of the pipes for sodium, this pipe arrangement being based on a superheater 1A and an evaporator 1B.
  • the steam generator 1 is constituted by the superheater lA and the evaporator lB which have the same structure with respect to each other.
  • Fig. 3A shows a general example of a secondary sodium system loop of a fast breeder reactor which includes the above-described steam generator 1 of the first embodiment in the present invention.
  • This system loop is constituted by an intermediate heat exhanger 23, the steam generator 1, a circulating pump 24 and a hot leg pipe 31A, a middle leg pipe 32A and a cold leg pipe 33A.
  • the intermediate heat exhanger 23 performs the thermal exchange in regard to the primary sodium and the secondary sodium.
  • the steam generator 1 produces vapor by effecting a thermal exchange between the feed-water and the secondary sodium with high temperature which is transmitted from the intermediate heat exchanger 23.
  • the circulating pump 24 circulates the secondary sodium.
  • the high temperature sodium moved from an intermediate heat exchanger 23 flows in via the sodium inlet pipe 10 of the superheater 1A and then flows out via the sodium outlet pipe 9.
  • the sodium outlet pipe 9 of the superheater lA is communicated with the sodium inlet pipe 10 of the evaporator 1B through the cold leg pipe 33A.
  • the sodium transmitted; from the superheater lA flows via the sodium inlet pipe 10 of the evaporator lB into the evaporator 1B and then flows ⁇ out through the sodium outlet pipe 9.
  • all the sodium pipes that is the hot leg pipe 31A, the middle pipe 32A and the cold pipe 33A, are provided on the upper side of the superheater lA and the evaporator 1B. Therefore, the sodium within the steam generator 1 does not flow out at all even if the sodium pipes 31A, 32A and 33A are damaged. The amount of leaked sodium can be minimized as compared with the prior arts wherein the sodium pipe in the proximity of the sodium outlet nozzle is damaged.
  • Fig. 3A is a schematic diagram of a secondary sodium system loop of one embodiment which employs the steam generator 1 constituted by the superheater lA and the evaporator 1B according to the present invention.
  • Fig. 3A in comparison with Fig. 3B which shows the schematic diagram of the secondary sodium system loop of the prior art, the piping in this case can be eliminated when the above first embodiment of the present invention is adopted. !
  • the constitution of the steam generator takes only one unit, that is, in the case of the continuous percolation, it is possible to reduce the number of pipes as well as the space for disposing the pipes in regard to the secondary sodium system loop by dint of adopting the present invention. Moreover, it obviously reduces the extent of damage of a sodium fire occurs.
  • Fig. 4 shows a steam generator of a second embodiment according to the present invention. It is shown in Fig. 4 an arrangement wherein an inner shroud 41 provides a metal bellows 42 thereof and a metal bellows 42 as a displacement absorption mechanism is provided within the barrel 3.
  • the inner shroud 41 has an upper end opening 41a and a lower end opening 41b.
  • the metal bellows 42 absorbs the difference in thermal expansion between the sodium outlet pipe 9 and the barrel 3.
  • the sodium outlet pipe 9 is connected to an upper end opening 41a of the inner shroud 41 by means of the metal bellows 42.
  • Fig. 5 shows a steam generator of a third embodiment according to the present invention.
  • Fig. 5 shows an arrangement wherein the whole inside area of an inner shroud 51 is employed as an offtake for sodium.
  • the inner shroud 5 takes a double pipe structure as shown in Fig. 5a in order that the thermal exchange between the sodium moving on the outside of the inner shroud 51 and the sodium moving on the inside of the inner shroud 51 is not permit to occur.
  • a gap 52 formed between the inside pipe and the outside pipe of the inner shroud 51 is filled with an inert gas.
  • the inner shroud 51 has an upper end opening 51a and a - lower end opening 51b.
  • the sodium flows into the lower end opening 51b of the inner shroud 51 and flows out through the upper end opening 51a of the inner shroud 51 and the outlet pipe 9.
  • the inner shroud 51 and the outlet. pipe are integrally formed therewith.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Details Of Heat-Exchange And Heat-Transfer (AREA)
EP19850112524 1984-10-05 1985-10-03 Générateur de vapeur Expired EP0178545B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59208245A JPS6189401A (ja) 1984-10-05 1984-10-05 蒸気発生器
JP208245/84 1984-10-05

Publications (2)

Publication Number Publication Date
EP0178545A1 true EP0178545A1 (fr) 1986-04-23
EP0178545B1 EP0178545B1 (fr) 1988-07-06

Family

ID=16553052

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850112524 Expired EP0178545B1 (fr) 1984-10-05 1985-10-03 Générateur de vapeur

Country Status (3)

Country Link
EP (1) EP0178545B1 (fr)
JP (1) JPS6189401A (fr)
DE (1) DE3563649D1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5676894B2 (ja) * 2010-03-17 2015-02-25 日本発條株式会社 金属プレートと伝熱管との固定構造

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3059908A (en) * 1959-09-29 1962-10-23 Iii Thomas H Fox Heat exchanger
FR1392058A (fr) * 1964-02-28 1965-03-12 Babcock & Wilcox Co Générateur de vapeur
FR1497102A (fr) * 1966-10-20 1967-10-06 Babcock & Wilcox Ltd Perfectionnements aux échangeurs de chaleur
FR2321750A1 (fr) * 1975-08-22 1977-03-18 Commissariat Energie Atomique Perfectionnement apporte aux circuits secondaires d'un reacteur nucleaire
FR2379881A1 (fr) * 1977-02-04 1978-09-01 Commissariat Energie Atomique Bloc-pompe echangeur de chaleur pour reacteurs nucleaires

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3059908A (en) * 1959-09-29 1962-10-23 Iii Thomas H Fox Heat exchanger
FR1392058A (fr) * 1964-02-28 1965-03-12 Babcock & Wilcox Co Générateur de vapeur
FR1497102A (fr) * 1966-10-20 1967-10-06 Babcock & Wilcox Ltd Perfectionnements aux échangeurs de chaleur
FR2321750A1 (fr) * 1975-08-22 1977-03-18 Commissariat Energie Atomique Perfectionnement apporte aux circuits secondaires d'un reacteur nucleaire
FR2379881A1 (fr) * 1977-02-04 1978-09-01 Commissariat Energie Atomique Bloc-pompe echangeur de chaleur pour reacteurs nucleaires

Also Published As

Publication number Publication date
JPS6189401A (ja) 1986-05-07
DE3563649D1 (en) 1988-08-11
EP0178545B1 (fr) 1988-07-06

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