DE1119424B - Steam generator - Google Patents

Description

GERMAN

PATENT OFFICE

R 20146 Vmc / 21g

REGISTRATION DATE. 6 DECEMBER 1956

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL; DECEMBER 14, 1961

The invention relates to a steam generator consisting of a nuclear reactor with a closed Coolant circuit and one by the heat extracted from the reactor coolant heated water evaporator, which are both arranged in a common and closed housing are.

Steam generators of this type are known. In these, the heat exchange tubes of the evaporator are immersed into the coolant circuit. The housing is not divided.

In contrast, the steam generator according to the invention is characterized in that the housing is divided by a partition into two chambers, that one chamber receives the nuclear reactor and the second chamber the water to be evaporated and one belonging to the reactor coolant circuit Includes tube bundle. While in the known steam generator, the entire housing the high Is exposed to the pressure of the reactor coolant, this high prevails in the present steam generator Pressure only inside the reactor chamber and in the heat exchange tubes through which the coolant flows.

In addition, the heat exchange tubes of the evaporator are located in the known steam generator, which are exposed to a relatively low internal pressure within the housing, which, since it acts as a reactor coolant line, is exposed to very high internal pressure. With this one Steam generators, on the other hand, run through the coolant pipes exposed to the high internal pressure inside the evaporator chamber, which is exposed to a low internal pressure.

So in the case of the known steam generator, the outer wall of the housing has to bear the full pressure of the Take up reactor coolant, so is the pressure difference between the outer space and the inner space in the case of the coolant pipes of the present steam generator around the inside of the evaporator chamber prevailing pressure reduced.

Even if in the embodiment described below, three by two partition walls separate chambers are provided, the subdivision into two chambers is sufficient, if you do without a pump-around unit and use the steam generator a natural circulation of the coolant operates.

In any case, it is essential that the coolant tubes are in a chamber that is completely separate from the reactor are housed.

In a preferred embodiment, however, is a steam generator

Applicant:

Rolls Royce Limited,
Derby, Derby (Great Britain)

Representative: Dipl.-Ing. F. Weickmann,

Dr.-Ing. A. Weickmann

and Dipl.-Ing. H. Weickmann, patent attorneys,

Munich 2, Brunnstr. 8/9

Claimed priority:

Great Britain of December 20, 1955 (No. 36 562/55)
and November 28, 1956

Cecil Alastair Comyns-Carr,

Coxbench, Derby (Great Britain),

has been named as the inventor

as already indicated, a further partition is provided, the second chamber a third Separates chamber. In this third chamber there is a pump unit for circulating the Reactor coolant. The tubes of said tube bundle run from one partition to the other and are attached at their ends to these partition walls.

The second chamber is preferably cylindrical in shape, and the tubes, part of which are for the Reactor coolant transport from the reactor chamber to the pumping chamber is determined and the rest for the coolant transport from the pumping chamber back to the reactor chamber, run in parallel to the axial direction of the cylindrical chamber.

The tubes are expediently arranged so that with different expansion of the tubes and the Housing no excessive stresses occur. Each tube preferably consists of a central, part running parallel to the axis of the chamber as well as end sections inclined towards this axis, which lead to collecting heads connected to the partition walls.

In a further advantageous embodiment, the reactor chamber is in an annular coolant inlet space, which the coolant from the pipes

109 749/460

flows in, an outer annular space, which receives the coolant from the coolant inlet space, a Transitional space through which the coolant from the outer annular space into an inside it Annular space located central space passes, and an exit space through which the coolant flows from the central space to the tubes intended for the coolant outflow, divided.

The pumping chamber preferably contains a plurality of impeller pumps through which there is axial flow. By a The subdivision within the pumping chamber is a suction space and an outflow space around this suction space formed, and there is one pump in series with the other in the outflow space. in the suction chamber - the pump is switched on.

In a further embodiment, a steam boiler is located outside the housing above the second chamber provided, and there is a circulation pump system between the steam boiler and the second chamber.

Further details emerge from the following description of an exemplary embodiment according to the invention with reference to the drawing.

The steam generator comprises a housing 10 of sufficient strength for the expected operating pressures. The housing, such as a welded structure, has a generally cylindrical shape Middle part 11 with frustoconical transition zones 12 and 14. To the frustoconical transition zone 12 connects to a cylindrical extension 13, the diameter of which is smaller than that of the cylindrical central part 11 and to the frustoconical transition zone 14 closes a hemispherical Dome 15, the diameter of which is approximately the same as that of the cylindrical extension 13. Two bowl-shaped, inner partitions 16 and 17 divide the housing into three chambers 18, 19 and 20; the first partition 16 is connected to the housing in the plane in which the frustoconical transition zone 12 merges into the cylindrical extension and is after the first chamber 18, inside the cylindrical extension 13, concave towards the second chamber 19, in the interior of the cylindrical central part 11, convex. The second partition 17 is in the Plane connected to the housing in which the dome 15 and the frustoconical part 14 into one another pass over; this partition is convex towards the second chamber 19 and towards one third chamber 20, inside the dome 15, concave. The opposite of the first partition wall 16 The front side of the chamber 18 is closed with a removable cover plate 21; the lid attachment is able to withstand the high pressures prevailing in the chamber.

In operation, the axis of the housing lies in a horizontal plane.

The first or reactor chamber 18 encloses a water-cooled nuclear reactor 22; the path of the coolant in this reactor runs from a coolant inlet space located next to the intermediate wall 16 23 through an outer annular chamber 24 of the reactor core 25 to the cover plate of the chamber and from this through the middle part of the reactor core 25 back to a coolant outlet space 26, the lies within the entry space 23.

The second or evaporator chamber 19 comprises a tube bundle 27 in which the reactor coolant is cooled with steam generation. The tube bundle comprises a plurality of pairs belonging together Manifolds 28, 29; these manifolds are welded into bores that extend over the two intermediate walls 16 and 17 of the Housing are distributed. The one manifold of a pair of manifolds is in each case with the Reactor chamber 18 connected, while the other manifold of this pair of manifolds is connected to the third chamber 20. Every

ίο Manifold 28 is aligned with the associated manifold 29. Some of the collecting lines 28 are connected to the coolant inlet space 23. The others are connected to the coolant outlet space 26 of the reactor chamber. The tube bundle further includes a plurality of tubing strings 30 extending generally axially through the second chamber get lost. The pipes of a string are each connected to a pair of manifolds. Each the pipes of the pipe strings 30 consists of a horizontal center piece and end pieces that extend Connect to the middle piece at an obtuse angle and with the associated manifolds 28, 29 are connected. Each tube 30 (and also the tube bundle 27 as a whole) has the shape of a flattened one U; the center pieces of the tubes are closer to the bottom of the evaporation chamber 19 than the Ceiling and run below the water level of the evaporation chamber. The tubes 30 are designed so that a different thermal expansion of the pipe elements and the housing is permissible without excessively high stresses occurring in the pipe elements.

The evaporator chamber has a feed water inlet 31 in its bottom and a steam outlet 32 in her blanket; the water is heated by contact with the tube bundle 27.

According to another embodiment, an upper boiler can be provided above the housing 10 and the water from chamber 19 to the top kettle and back to the bottom part of the chamber 19 are circulated.

The third (or pump) chamber has two impeller cooling pumps 33 and 34 through which there is axial flow equipped; an inner partition 35 separates a central suction space 36 from an outflow space 37; each of the rooms accommodates one of the pumps, which are connected in series. The cooling water flows from the pipes 30, which are connected to the header pipes 28 and thus to the coolant outlet space 26 are, in the suction chamber 36, through the two series-connected pumps 33, 34 in the Outflow space 37 and from this outflow space 37 into the remaining tubes 30, which are after the coolant inlet space 23 of the reactor chamber.

The drive shafts of the pumps are connected through the dome 15 to drive motors 38 which are provided outside the housing.
As is evident from the above description, the reactor and the coolant circuit represent a unit; this arrangement has the considerable advantage for power plants that external lines carrying radioactive water are avoided and shielding is facilitated. Since the cooling water temperature is about (600 ° F) 315 ° C, the cooling water must be kept under high pressure, about (2,000 pounds per square inch) 146 kg / cm ² to prevent evaporation. In the present

Steam generators do not require external lines and connections that can withstand these high pressures. Since the tubes of the tube bundle run in a space containing high pressure steam of about (400 pounds per square inch) 29 kg / cm ² , the pressure difference across the tube walls is less than if the cooling tubes were led outside the housing at atmospheric pressure.

Another advantage of the present evaporator is that it is substantially unitary and symmetrical distribution of the coolant flow at the inlet and outlet of the reactor is present.

The steam generator described above can be used as part of a steam turbine ship propulsion system Design are used. According to one embodiment, the steam is from the steam generator Via a turbine 40 with a high pressure part 41 and a low pressure part 42 as well as a Turbine short-circuit channel 43 and a control valve 44 in this short-circuit channel after a condenser 50 headed. The condensate is fed from the condenser to feed water heaters 51 and 52 pumps, in which the water is heated by steam diverted from the turbine; in the end the water is pumped back to the evaporator chamber 19 by feed water pumps 53, 54.

Claims (7)

PATENT CLAIMS: 1. Steam generator, consisting of a nuclear reactor with a closed coolant circuit and a water evaporator heated by the heat extracted from the reactor coolant, both of which are arranged in a common and closed housing, characterized in that the housing is divided into two chambers ( 18, 19) that one chamber (18) receives the nuclear reactor (22) and the second chamber (19) contains the water to be evaporated and a tube bundle (27, 30) belonging to the reactor coolant circuit. 2. Steam generator according to claim 1, characterized in that by a further partition (17) from the second chamber (19) a third chamber (20) is separated, which a Pump unit (33, 34) for circulating the reactor cooling means, and that the pipes (30) of the tube bundle (27) run from one partition to the other and at their Ends are attached to these partitions (16,17). 3. Steam generator according to claim 1 or 2, characterized in that the second chamber (19) has a cylindrical shape and that the tubes (30), a part of which is used for transporting the reactor coolant from the reactor chamber (18) to the pumping chamber (20) and the remainder for the coolant transport from the pumping chamber (20) back to the reactor chamber (18), run parallel to the axial direction of the cylindrical chamber (19). 4. Steam generator according to claim 1 or 2, characterized in that each tube (30) consists of a central part running parallel to the axis of the chamber (19), as well as against this axis inclined end sections, which are connected to the partition walls (16, 17) Guide collecting heads (29). 5. Steam generator according to one or more of claims 1 to 4, characterized in that that the reactor chamber (18) is divided into an annular coolant inlet space (23), to which the coolant flows from the tubes (30), an outer annular space (24), which the coolant from the coolant inlet space (23) receives a transition space through which the coolant from the outer annular space (24) into a central space located within this annular space (25) crosses an outlet space (26) through which the coolant from the central space flows according to the pipes (30) intended for the coolant outflow. 6. Steam generator according to one or more of claims 2 to 5, characterized in that that the pumping chamber contains a plurality of axially flowed through impeller pumps (33, 34) and that by a subdivision within the pump chamber a suction space and around this suction space around an outflow space are formed and that the one - lying in the outflow space - pump in Series to the other — in the suction chamber Hegenden— Pump is switched. 7. Steam generator according to one or more of claims 1 to 6, characterized in that that a steam boiler is provided outside the housing (10) above the second chamber, and that a circulating pump system is located between the steam boiler and the second chamber. Considered publications:
Münzinger, "Atomkraft", 1955, Springer-Verlag, p. 24. For this purpose, 1 sheet of drawings i 109 749/460 12.61