JPH05164878A - Steam separator and vapor dryer integral structure - Google Patents

Abstract

PURPOSE:To enhance the performance of each steam separator as well as to facilitate maintenance by interposing a header between each steam separator and a vapor dryer, and thereby integrating them into one structure. CONSTITUTION:Gas-liquid two phase flow B generated through nuclear reaction by nuclear rods 8 goes up in flow paths among the fuel rods 8, is once collected into a space made up of a reactor core shroud 7 and of a shroud head 10, and is then separated again into hot water fluid A and vapor C within a steam separator 11 made of a plural number of steam separating pipes 11a. Vapor flow C containing mist liquid drops passes through the inside of a header 14, and carried-over liquid component is cut off by a steam separator 12 which is formed into an integral structure through the steam separator 11 and the header 14, so that it flows out of a main steam nozzle 13 toward a steam turbine. Meanwhile, hot water A separated within the steam separator 11 goes down through a downcomer section formed out of the inside of a reactor 1 and a reactor core head 7 so as to be sucked in an internal pump 2. Hot water discharged out by the pump 2 then flows in the reactor 1 so as to be returned to the fuel rods 8 again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal structure of a nuclear reactor, and more particularly, to an improvement in two-phase flow separation performance and easy maintenance by integrating a steam separator with a steam dryer. The present invention relates to a preferable in-core structure integration mechanism.

[0002]

2. Description of the Related Art A conventional reactor pressure vessel is shown in FIG. Compared with FIG. 1 which is one embodiment of the present invention, the steam separator 11
The steam dryer 12 is independently installed as a device. Originally, the steam separator 11 actively separates the hot water / steam two-phase flow B generated in the fuel rod 8 on the free liquid surface, and carries the steam contained in the hot water A returning to the downcomer. This is to prevent the problem. The steam dryer 12 is for preventing the steam flow C from carrying over the moisture mist liquid contained in the steam phase-separated by the steam separator 11 to the steam turbine.

Therefore, although the early reactors were appropriate, careful attention was paid to the various reliability of this type of actual equipment. For example, the steam separator 11 has a free liquid level at the center of the separation tube 11a, and when rising in this by the gas-liquid two-phase flow B, it relates to fluid vibration based on the two-phase flow differential pressure inside and outside the separation tube. Caution must be taken. Further, the steam dryer 12 separates mist droplets due to the difference between the inertial force of the vapor stream and the mist liquid mass contained in the vapor, or the force of gravity of the droplets. Therefore, in the steam dryer 12 having the corrugated plate structure of the thin plate, it is necessary to pay attention to the vibration due to the fluid force based on the differential pressure as in the above.

Further, it is necessary to solve the technical problems of the separation performance of these two and the reduction of pressure loss, and at the same time, the maintenance work of these devices at the time of the regular inspection of the reactor is difficult to work because of the complicated structure arrangement. There are problems such as badness.

[0005]

The above-mentioned prior art is included in the steam flow above and below the steam separator for phase-separating the gas-liquid two-phase flow generated by the fuel rods on the free liquid surface. A steam dryer for removing the wet water contained therein is installed in the reactor as a separate element in the reactor pressure vessel.
The internal structure of a nuclear reactor has a complicated support structure to ensure the reliability of the equipment structure, because each equipment receives hydrodynamic force by hot water flow or steam flow. Problems such as complexity may be considered.

The object of the present invention is to improve the steam-water separation performance by integrating the steam-water separator and the steam dryer into an integrated structure, and to simplify the equipment as the reactor internal structure to facilitate maintenance. To do.

[0007]

In order to achieve the above object, the present invention provides a header between devices so that a conventional steam-water separator and a steam dryer are integrated with each other. It efficiently removes water from the hot water / steam two-phase flow, and improves the water-water separation performance and facilitates maintenance.

[0008]

In order to integrate the steam separator with the steam dryer, if a header is provided between the steam separator and the steam separator, in the case of the steam separator, as compared with the conventional steam separator consisting of a plurality of pipes, From the viewpoint of drain discharge of the liquid collected in the header, the liquid separation efficiency is improved and the pressure loss on the steam side is reduced. Also,
The carrier carrier of the vapor contained in the hot water descending in the downcomer flowing into the internal pump is suppressed.
Further, if at least one liquid film removing mechanism for separating a large liquid mass is installed in the gas-water separation pipe, the gas-liquid separation efficiency is further improved. In addition, if a collision plate is installed in the header, the liquid mass or mist droplets carried over in the vapor-liquid two-phase steam rising in the water-water separation pipe collide with the collision plate, and The liquid can be cut into.

With the above three mechanisms, the separation efficiency of the steam-water separator and the steam dryer, which are the reactor internals of the nuclear reactor, is improved.
It has advantages such as reduction of pressure loss, suppression of fluid vibration, and easy maintenance. By these actions, the structure in the upper part of the reactor becomes compact, and the safety of the reactor pressure vessel,
Ensure reliability.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a vertical sectional view of a reactor pressure vessel.
First, the structure of the reactor pressure vessel will be described. In this basic structure, a fuel rod 8 for causing a reaction in a reactor pressure vessel 1 is installed inside a core shroud 7 in the lower part of the vessel, and a control rod guide tube 4 and a control rod guide tube are provided below the fuel rod 8. The drive mechanism 3 is installed. And these devices are being fixed by the core support plate 5, the fuel support metal fitting 6, etc. Further, the uppermost part of the fuel rod 8 is fixed by an upper support plate 9. On the other hand, several internal pumps 2 for circulating hot water A are installed in the circumferential direction between the reactor pressure vessel 1 and the core shroud 7.

Next, in order to take out steam from the gas-liquid two-phase flow generated by boiling in the fuel rods 8, there is a shroud head 10 at the upper part of the core shroud 7, and a large number of steam-water separation pipes 11a are provided at the upper part. A steam separator 11 is installed. Moreover, the steam separator 11 and the header 14 are provided on the upper part thereof.
The steam dryer 12 is integrated via the above. Here, a drain water return mechanism 15 is installed near the outer periphery of the header 14. Furthermore, the reactor pressure vessel 1
There is also a main steam nozzle 13 at the upper part of which the steam generated in the furnace flows out.

Next, the operation inside the reactor pressure vessel 1 will be described. First, the gas-liquid two-phase flow B generated by the nuclear reaction in the fuel rods 8 rises in the flow path between the fuel rods 8 in the fuel channel,
These gas-liquid two-phase flows are once gathered in the space formed by the core shroud 7 and the shroud head 10, and again in the steam-water separator 11 composed of a large number of steam-water separation pipes 11a, the hot-water liquid A and the steam. It is separated into C. Then, the steam flow C containing the mist droplets passes through the inside of the header 14, and the steam dryer 12
The liquid component carried over at is cut and flows out from the main steam nozzle 13 to the steam turbine. On the other hand, the hot water A separated in the steam separator 11 descends through the downcomer portion composed of the reactor interior 1 and the core shroud 7, and is sucked into the internal pump 2. Then, the hot water discharged by the internal pump 2 flows into the reactor from the leg portion opened at the lower part of the core shroud 7, flows in the control rod guide tube drive mechanism 3 in a cross flow, and returns to the fuel rod 8 again.

The features of the present invention will be described with reference to FIG. First, the gas-liquid two-phase flow B rising in the gas-water separation pipe 11a removes the liquid film of the annular two-phase flow around the inside of the pipe by at least one liquid film removing mechanism 16 to turn the liquid mass into hot water on the free liquid surface. It uses gravity to fall. Most of the hot water liquid is cut by the liquid film removing mechanism 16, but still large mist droplets contained in C in the steam flow are cut in the header, and the collected liquid component is at the bottom of the header 14. The drain water return mechanism 15 installed at the position returns to the hot water free liquid level.

In this way, the steam C having a low mist humidity passes through the steam dryer 12 installed at the upper part of the header 14 to form steam having a necessary degree of wetness, and the steam from the reactor main body is mainly formed. Outflow through the steam nozzle. Therefore, by integrating the steam separator with the steam dryer via the header, the separation efficiency can be improved and the maintenance at the time of regular inspection can be facilitated.

Another embodiment of the present invention will be described with reference to FIG. The present invention differs from the inventions of FIGS. 1 and 2 in that at least one collision plate 17 is provided in the header 14 so that the gas-liquid two-phase flow rising in the water-water separation pipe 11a of the water-water separator 11 is increased. The vapor lump C or the mist droplets that have carried over collide with the vapor flow C of 1. to take out vapor.

Therefore, if this structure is installed, the steam-water separator 11 and the steam dryer 12 are integrated with each other through the header 14 to sufficiently remove the hot water component contained on the steam side. Therefore, it is possible to provide the separation mechanism in which the separation efficiency is improved and the pressure loss is not increased. In addition, maintenance at the time of regular inspection becomes easy, and the reactor internal structure has high safety and reliability.

[0017]

According to the present invention, the header is provided between the steam separator and the steam dryer, so that the separator has an integrated structure, and the steam separation performance is improved and the maintenance at the time of regular inspection is easy. From the viewpoint of reliability, the structure is simplified, and it is possible to provide a reactor internal structure with high performance, safety and reliability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a reactor pressure vessel according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the steam-water separator / steam dryer integrated structure of FIG.

FIG. 3 is an enlarged view of a steam-water separator / steam dryer integrated structure according to another embodiment of the present invention.

FIG. 4 is a vertical sectional view of a conventional reactor pressure vessel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Internal pump, 3 ... Control rod guide tube drive mechanism, 4 ... Control rod guide tube, 5 ... Core support plate, 6 ... Fuel support metal fitting, 7 ... Core shroud, 8 ... Fuel rod , 9 ... Upper lattice plate, 10 ... Shroud head, 11 ...
Air / water separator, 11a ... Air / water separation tube, 12 ... Steam dryer,
13 ... Main steam nozzle, 14 ... Header, 15 ... Drain water return mechanism.

Front Page Continuation (72) Inventor Norio Angaira 502 Kintatemachi, Tsuchiura City, Ibaraki Prefecture Inside the Ritsuryo Corporation Mechanical Research Laboratory

Claims (3)

[Claims] 1. A header and drain having a steam / water separator installed in the upper part of a shroud head and a steam dryer separately installed in the upper part of the steam / water separator in an internal space of a nuclear reactor. A water-water separator / steam dryer integrated structure characterized by installing a water return mechanism and integrating the two elements. 2. The liquid film removing mechanism for returning at least one separated water to the separation pipe of the steam separator according to claim 1,
Steam-water separator and steam dryer integrated structure with improved separation performance. 3. The steam-water separator / steam dryer integrated structure according to claim 1, wherein a carry-over preventing collision plate is installed in the header.