JPS61159088A - Heat exchanger - Google Patents

Abstract

PURPOSE:To eliminate a heat exchanger and a guide vessel for primary main circulating pump by a method wherein a pump is equipped in the space of the heat exchanger, in which an electric heater is not equipped, and an outside shell is utilized as a secondary sodium boundary while a guide pipe is provided in the outlet pipeline of primary system. CONSTITUTION:Primary cooling sodium flows through an inlet nozzle 13a, flows down the outside of a heat insulating wall 29, flows into an electric heater tube 12 through an inlet window 14, descends the outside, flows into an intermediate prenum 30 and pump hydraulic section 31 and is flowed into a primary system pipeline 4 through a delivery pipe 26 by the boosting of an impeller. Secondary system sodium from the inlet nozzle 17 descends between an outer cylinder 8 and an inner cylinder 9, ascends from a lower prenum 19 through the electric heater tube 12 and flows out of an outlet nozzle 21. Sodium boundary, above the outer cylinder 8 of the heat exchanger, is higher than a level necessary for securing cooling material and a part lower than said boundary is enclosed by secondary cooling material having a high pressure, therefore, the primary cooling material will never leak to the outside even if the outer cylinder 8 is broken. The guide pipe 28 is provided at a part lower than the system level of primary sodium of the pipeline connected to the outlet nozzle 16 of the primary system.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is used in a reactor cooling system for a liquid gold wave-cooled fast breeder reactor, in which a primary main circulation pump is integrated into a conventional heat exchanger, and This invention relates to a heat exchanger that has been made more compact by eliminating the guard vessel.

[Technical background of the invention] A reactor cooling system for a loop-type liquid metal cooled fast breeder reactor is
As shown in FIG. 5, a primary main circulation pump 3 is disposed between the reactor vessel 1 and the heat exchanger 2, and these are connected by a primary main pipe 4. In order to store the primary coolant that leaked when the primary main piping 4 was damaged and to ensure the liquid level in the reactor vessel, the reactor vessel 1, heat exchanger 2, and primary main circulation bomb 3 are equipped with atomic bombs, respectively. A furnace vessel guard-vessel 5, a heat exchanger guard-vessel 6, and a primary main circulation pump guard-vessel 7 are provided.

The heat exchanger 2 is a shell-and-tube type heat exchanger, as shown in FIG. board 10,
A lower tube plate 11 is provided, and a large number of electric heating tubes 12 are bundled between the upper and lower tube plates 10 and 11.

The secondary coolant flows from the primary system inlet nozzle 13 provided on the upper side surface of the outer shell 8, and flows into the inner shell 9 through the inlet window 14 provided on the upper side surface of the inner shell 9. The inflowing coolant passes through an outlet window 15 provided on the lower side surface of the inner shell 9, flows out from a primary system outlet nozzle 16 provided at the lower end of the outer shell 9, and flows into the primary main pipe 4.

On the other hand, the secondary coolant flows in from the secondary system inlet nozzle 17,
The water flows into the lower blennium 19 through the downcomer pipe 18, is reversed at the brenum 19, flows from the downcomer pipe 11 into each electric heating tube 12, passes from the upper tube plate 10 through the upper blennium 20, and flows out from the secondary system outlet nozzle 21. In addition, in the figure, the reference numeral 22 is a bypass prevention plate.

[Problems with the background art] However, in such a conventional nuclear reactor cooling system,
Guard vessels 5 were installed in the reactor vessel 1, intermediate heat exchanger 2, and primary main circulation pump 3 in response to a piping breakage accident.
．． 6.7, while the primary system outlet nozzle 16 of the heat exchanger 2 is connected below the outer shell 8, the guard
A vertical pipe 4a is required to stand up the primary main pipe 4 within the vessel 6. Similarly, since the inlet/outlet nozzle of the primary main circulation pump 3 is also installed below, vertical piping 4b, 4C for starting the primary main piping 4 within the guard vessel 7 is required, and these equipment, piping, and The amount of support is large, and its design is also difficult.

In addition, the routing of the primary main piping 4 that interconnects the reactor vessel 1, heat exchanger 2, and main circulation pump 3 becomes complicated, which increases the diameter of the reactor vessel 1, which in turn causes the reactor This is a cause that prevents the overall building from becoming more compact.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its first purpose is to integrate the heat exchanger 2 and the primary main circulation pump 3, and to integrate the heat exchanger 2 and the primary main circulation pump 3. Bonp 3
The objective is to provide a compact heat exchanger that eliminates the guard-vessel 6.7.

A second purpose is to provide a compact heat exchanger in which the heat exchanger 2 and the primary main circulation pump 3 are integrated, and at the same time the heat transfer coefficient on the shell side of the heat exchanger 2 is improved.

Furthermore, the third purpose is to install the heat exchanger 2 and the primary main circulation pump 3.
The objective is to provide a compact heat exchanger by making the insertion diameter of the pump as small as possible.

[Summary of the invention] That is, the heat exchanger according to the present invention has a pump installed in a non-electric heating space formed in the center of an electric heating tube bundle of the heat exchanger, and an outer shell of the heat exchanger that is This is the sodium boundary.

The primary system inlet nozzle of the heat exchanger will be installed at a level higher than that required to secure coolant in the event of damage to the primary main piping, and the secondary system outlet piping will be provided with a guide vibrator only at the section below the system level. There is, and its structure is as follows.

That is, a bundle of electric heating tubes is installed in the inner shell to form a flow path for the secondary cooling system, a circulation pump is installed in the center of a cylindrical heat insulating wall provided concentrically with the inner shell, and the electric heating tube A primary cooling system flow path is formed through the circulation pump on the outside of the body, and a secondary sodium flow path is formed between the inner shell and the outer shell, and a primary sodium outlet nozzle is provided at the lower part of the outer shell. The main piping is connected to the primary main piping, and the outside of the main piping is surrounded by a guide pipe.

[Embodiment of the Invention] An embodiment of the heat exchanger according to the present invention is shown in Figs. 1 and 2 below.
This will be explained with reference to the figures.

That is, in FIG. 1, the heat exchanger 2a includes an outer shell 8,
An inner shell 9 supported within the outer shell 8, a pair of earthen pipe plates 10 and a lower tube plate 11 provided at both upper and lower ends of the inner shell 9, and a large number of tubes bound by the upper and lower tube plates 10 and 11. , a primary system inlet nozzle 13a provided on the shoulder of the outer shell 8, a primary system outlet nozzle 16a provided on the lower part of the outer shell 8, and a secondary nozzle provided on the upper side of the outer shell 8. The system inlet nozzle 17a is located inside the tube bundle of the electric heating tubes 12, and its upper end is fixed to the upper inner wall surface of the outer shell 8, and its lower end is connected to the lower tube plate 1.
A shroud 23 fixed to the upper tube plate 10 and suspended from the upper tube plate 10, an inlet window 14 provided on the upper part of the shroud 23, an outlet window 15 provided in the shroud 23, and an inner side of the shroud 23. It is composed of a heat insulating wall 29 suspended from the upper part of the outer shell 8, and a bypass prevention bellows 22 for partitioning the space between the heat insulating wall 29 and the shroud 23. In addition, the rising part of the primary system main piping 4 connected to the secondary system outlet nozzle 16 is a guard pipe 2.
It is surrounded by 8.

On the other hand, in the main circulation pump 3a, the pump casing 33 is suspended from the top of the outer body 8 by a seven-lunge structure 34, and a blemish 30 part is housed within a double cylindrical heat insulating wall 29 that seals gas inside. It is inserted and installed.

The pump 3a has a structure in which a drive motor (not shown) is disposed through a single motor 25 at the upper part of the pump 3a, and a pilot section 31 is provided at the tip of a shaft 35 connected to the motor.

Pump 3a is a mechanical centrifugal pump with a free liquid level 44, which sucks the primary sodium in the blemish 30. A discharge pipe 26 is provided on the outlet side of the hydro section 31, and the discharge pipe 26 and the primary system outlet nozzle 16 are connected by a slide joint 27.

That is, as shown in an enlarged view of the main part of the pump 3a in FIG. 2, the main part, the hydro section 31, has, for example, four impellers 36 attached to a shaft 35, and two polutes at the impeller outlet. It consists of a casing 37, several downcomers 38 on the outside of the porute casing, and a hydrostatic bearing 39 that supports the shaft 35.

Several down ducks 38 are placed at the lower end of the hydro section 31 and merge to form the discharge pipe 26. Note that reference numeral 39 denotes a bearing support, which is attached to the inner surface of the pump casing 33. Further, 40 is a high-pressure sodium supply pipe that supplies sodium to the upper bearing 41.

The sodium in the blennium 30 is sucked into the impeller 36, and as the impeller 36 rotates, the pressure increases in the polyneedle casing 38, passes through the down cuff 38, and is discharged into the discharge pipe 2.
6.

Next, the operation of the heat exchanger according to the above configuration will be explained.

In Fig. 1, high temperature primary cooling sodium transported from the reactor vessel (not shown) is transferred to the primary system inlet nozzle 13.
It flows into the primary upper blemish 32 from a, descends outside the heat insulating wall 29, and flows into the tube bundle of the electric heating tubes 12 through the inlet window 14 provided in the upper part of the shroud 23. Furthermore, the outside of the heating tube descends while exchanging heat with the sodium inside the heating tube,
It flows into the intermediate stub numeral 30 through an exit window 15 provided in the lower part of the shroud 23 .

Roughly speaking, the primary sodium that has flowed into the intermediate blennium 30 flows into the pump hydro section 31 and its
It is pressurized by an impeller built into the interior, passes through the discharge pipe 26,
It flows roughly through the secondary system from the outlet nozzle 16 to the primary system piping 4.

Further, the secondary system sodium flowing from the secondary system inlet nozzle 17 descends through the annulus space between the outer shell 8 and the inner shell 9,
Change the flow path by 180°C in the lower blennium section 19, and heat tube 12
It rises while exchanging heat with the primary sodium inside. The elevated secondary sodium enters the upper blemish part provided in the upper tube plate 10 and flows out from the secondary system outlet nozzle 21.

Furthermore, the upper part of the outer shell 8 of this heat exchanger, which forms the boundary between the sodium and the atmosphere, has a level above that required for securing the coolant for the reactor vessel even if it is damaged. Furthermore, below that level, the primary cooling boundary is always surrounded by secondary cooling, and even if part of that boundary is damaged, the secondary cooling is always maintained at a higher pressure than the primary cooling. Therefore, the secondary coolant will not leak to the outside.

In addition, the piping 5 connected to the secondary system outlet nozzle 16 is provided with a guard vibrator below the primary sodium system level, so that even if a part of the boundary of the secondary system piping is damaged, the sodium in the reactor vessel will be maintained as necessary. Always maintained above the level.

In FIG. 4, the heat generated in the reactor vessel 1 is transported through the primary main piping 4 by the primary cooling member circulated by the secondary main circulation bomb 3a, and is exchanged with the secondary coolant in the intermediate heat exchange 2a. The heat is exchanged and returned to the reactor vessel 1 via the primary main circulation pump 3a installed above the intermediate heat exchanger 2a and the secondary cooling pipe 4. If the reactor vessel 1 and the vertical pipe 27 connected to the inlet of the reactor vessel 1 and inside the guard-vessel 5 are damaged, the leaked primary coolant is stored inside the reactor vessel guard-vessel 5. , the coolant level within the reactor vessel 1 is ensured at or above the required level.

[Effects of the Invention] As explained above, the present invention does not have any influence on safety system problems and eliminates the need to install a secondary main circulation pump, a guard vessel, and a guard vessel for a heat exchanger. .

Further, there is no need to provide piping that connects the heat exchanger and the primary main circulation bomb or vertical primary main piping around the primary main circulation pump. Furthermore, it is possible not only to significantly reduce the amount of materials including support, etc., but also to simplify the equipment and piping system of the entire reactor cooling system.

A guard-vibrator is installed on the vertical primary main piping connected to the primary outlet of the heat exchanger.C1 The conventional large guard-vessel for the heat exchanger is removed, and a large amount of material is expected to be reduced. Ru.

Therefore, the diameter of the reactor containment vessel that houses the reactor cooling device can be reduced and made more compact, which in turn brings about significant effects such as making the entire nuclear couplant more compact.

Furthermore, in the heat exchanger, a skirt piece support 24 is installed on the outer shell of the heat exchanger, but the outer shell on which the support is installed is in contact with the secondary side inlet sodium part, so the temperature is about 35.
The temperature is about 0°C, and the structural soundness of the support structure is improved.

Regarding the flow of sodium on the secondary side, since the primary sodium flows uniformly in the circumferential direction from the entrance and exit windows provided at the upper and lower parts of the shroud, the electric heating performance can be improved. By adopting a double-row, both-inclusive type pump for the primary main circulation pump that is roughly inserted into the heat exchanger, the pump insertion diameter can be reduced, and the heat exchanger can be made more compact. .

In the above embodiment, a straight tube type electric heating tube is incorporated into the heating tube of the heat exchanger, but in order to further improve heat exchange performance and aim for compactness, the electric heating tube is of a helical coil type. FIG. 3 is a sectional view showing a heat exchanger incorporating a helical coil pump as another embodiment of the present invention.

The configuration, operation, effects, etc. of this embodiment are almost the same as those explained based on the embodiment of FIG.
Explanation will be omitted.

As for the type of pump built into the heat exchanger, as explained above, a double-row double-suction pump is considered the most preferable in terms of reducing the insertion diameter, but single-stage double-suction and two-stage Type suction or 3-row double suction is also possible.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of a heat exchanger according to the present invention, FIG. 2 is a longitudinal sectional view showing an enlarged main part of FIG. 1, and FIG. Vertical sectional view showing the main part of the example, No. 4
The figure is a system diagram showing an example of a nuclear reactor cooling system incorporating a heat exchanger according to the present invention, FIG. 5 is a system diagram showing a reactor cooling system incorporating a conventional heat exchanger, and FIG. FIG. 2 is a vertical cross-sectional view showing a conventional heat exchanger. 1......Reactor vessel 2.2a...
Heat exchanger 3.3a...-Secondary main circulation pump 4.4a, 4b, 4c...Primary main piping 5...
...Reactor vessel guard - Vessel 6...
・・・・・・・・・Heat exchanger guard - Vessel 7・
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・10...... Upper tube plate 11... Lower tube plate 12... Electric heating tube 13...・・・・・・・・・・・・-Next system inlet nozzle 14・
......... Entrance window 15... Exit window 16... Exit nozzle 17...
......Secondary system inlet nozzle 18...
...Downcomer 19...Plenum 20...
・・・・・・Upper plenum 21・・・・・・・・・
...Secondary system outlet nozzle 22... Bypass prevention plate 23... Shroud 24... Skirt piece support 25
......Motor stand 26...
...Discharge pipe 27...Thrust joint 28
...... Guard pipe 29...
......Insulating wall 30...Plenum part 31...
・・・・・・・・・Hydro part 32・・・・・・・・・
...-Plenum 33...Pump casing 34...7 Lange structure 35... Shaft 36...
・・・・・・・・・Impeller 37・・・・・・・・・・
・・Polyut Casing 38・・・・・・・・・・・
・Downcomer 39・・・・・・・・・Static pressure bearing 4
0......High pressure sodium piping 41.
・・・・・・・・・・・・Upper bearing 42・・・・・・・・・
...Bearing Support Agent Patent Attorney Sasa Suyama
- Figure 2 Fishing Figure 6 Procedures Amendment (method) % formula % ・26 Name of invention Heat exchanger 3, relationship with the person making the amendment case ・Patent applicant Horiyo, Saiwai Ward, Yozaki City, Kanagawa Prefecture Town 72 (307) Toshiba Corporation 4, Agent Address: 2-1-7 Kanda Tamachi, Chiyoda-ku, Tokyo 101 101 Between the 2nd and 3rd lines of page 1 of the statement of contents of the amendment [2, Patent Insert "Scope of Claims".

Claims (2)

[Claims] (1) An inner shell is provided concentrically with a secondary cooling system flow path in the outer shell, and a bundle of electric heating tubes bound by a pair of upper and lower tube plates is provided in the inner shell, and the inside of each electric heating tube is A circulation pump that communicates with the secondary system flow path, has a cylindrical shroud inside the electric heating tube bundle, and is surrounded by an insulating wall approximately in the center of the shroud, and is connected to each electric heating tube of the electric heating tube bundle. A primary cooling system flow path is formed on the outside of the outer shell, and a primary system outlet nozzle that communicates with the discharge pipe of the circulation pump is provided in the lower part of the outer shell to connect with the primary main piping, and the outside of the primary main piping is guided. A heat exchanger characterized by being surrounded by pipes. (2) The heat exchanger according to claim 1, wherein the heating tube bundle is composed of straight tube type heating tubes or helical coil type heating tubes.