JPH11142573A - Cooling structure of control rod for HTGR - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To allow the flow rate distribution of a coolant to a control rod guide tube to be adjusted arbitrarily and not to hinder swinging, rotation, and freedom in the vertical direction. A cylindrical guide cover is provided to pass through a guide tube support member, and a slide plate is attached to an outer peripheral surface of the guide cover. The upper end of the control rod guide tube 15 is fixed with an upper bundling plate 20, and a guide cover 23 penetrates a through hole 19 provided in the center of the upper bundling plate 20, and a slide plate is provided.
The lower surface of 22 contacts the upper surface of upper binding plate 20. The upper bundling plate 20 is provided with an inflow hole 21, which serves as an orifice for adjusting the flow rate of the coolant. The through hole of the wire rope 18 is closed by the slide plate 22 and the guide cover 23 that follow the elevating operation of the control rod guide tube 15, and the flow rate distribution can be arbitrarily adjusted by changing the diameter of the inflow hole 21. Does not inhibit

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control rod guide tube extending from a control rod driving device, such as a high-temperature gas-cooled reactor (hereinafter referred to as a high-temperature gas reactor), connected to a reactor core, and the inside of the control rod guide tube The present invention relates to a cooling structure of a control rod for a high-temperature gas reactor, which is configured to perform a vertical movement of the control rod.

[0002]

2. Description of the Related Art As shown in FIG. 2, a high-temperature gas furnace includes a furnace vessel 1, a core 2 housed inside the furnace vessel 1, a core supporting member 3 for supporting the core 2, and a furnace vessel 1. And a control rod driving device 5 built in a stand pipe 4 protruding upward.

[0003] The furnace vessel 1 is filled with a coolant of helium gas (hereinafter referred to as a coolant) at a high pressure of several tens of atmospheres, flows into the furnace vessel 1 from the outer tube 6, and enters the lower plenum 7.
The gas flows out of the furnace vessel 1 from the inner tube 11 while circulating through the furnace vessel 1 in the order of the gap 8, the upper plenum 9, the core 2, and the high-temperature plenum 10.

Generally, in a nuclear reactor, a fission reaction in the reactor core 2 is controlled by inserting or removing a control rod filled with a neutron absorbing material into or from the reactor core. There are various types of control rod driving devices 5 for driving the control rods. In a high-temperature gas furnace, the control rods are suspended by wire ropes, and the control rods are wound by winding and unwinding the wire ropes. Raise and lower.

Referring to FIG. 3, an outline of such a wire rope type control rod driving device 5 will be described. A plurality of control rod insertion holes 13 are formed in the core 2 supported on the hearth section 12 (only one is shown at the same time). Control rod guide tube 15 suspended from member 14
Are disposed on the same axis as the control rod insertion holes 13. The control rod 16 connected to the control rod driving device 5 via the connection bracket 17 and the wire rope 18 moves up and down in the control rod insertion hole 13 and the control rod guide tube 15. The control rod driving device 5 includes a wire winding / rewinding drum 5a, a motor 5b for rotating the drum 5a, and a gear group 5c.

The control rod guide tube 15 is used to cool the control rod 16.
It is necessary to allow the coolant to flow into the control rod insertion hole 13. In a conventional cooling structure for a control rod for a high-temperature gas furnace, the upper end of a control rod guide tube 15 is fixed by an upper bundle 20 as shown in FIG. After flowing between the upper bundling plates 20, the wire rope 18 provided on the upper surface of the upper bundling plate 20 flows in from a wire rope penetrating portion 19 that penetrates.

[0007]

As described above, in the conventional cooling structure for a control rod for a high-temperature gas reactor, the coolant flows in from the wire rope penetration portion 19 on the upper surface, but the control rod guide tube is provided.
In the coolant flow path following the control rod insertion hole 13 from the inside of 15, there is not provided any inflow point of the coolant flowing into the coolant flow path. Therefore,
In determining the flow rate distribution of the coolant to the control rod guide tube 15 in this cooling structure, the pressure loss at the wire rope penetration portion 19, that is, the shape of the penetration portion 19 is dominant.

However, in order to ensure the soundness of the wire rope 18, the wire rope penetration portion 19 needs to have a shape that avoids interference with the wire rope 18.
The diameter of the penetration portion 19 cannot be narrowed more than necessary.
Therefore, there is a problem that the flow rate distribution of the coolant to the control rod guide tube 15 cannot be adjusted to an appropriate flow rate due to the shape limitation of the wire rope penetration portion 19.

On the other hand, the graphite block and the upper shield constituting the core 2 are generally provided with a gap between adjacent blocks in terms of assembly. Only the position of the block may move, and the furnace vessel 1 and stand pipe 4
Considering factors such as machining accuracy, installation accuracy, inclination, etc., the axes of the control rod guides 15 and the control rod insertion holes 13 may not match.

Therefore, in this case, the control rod guide tube 15 is installed on the core in a tilted or rotated posture, and the relative positional relationship between the wire rope penetrating portion 19 and the wire rope 18 changes. As a result, the pressure loss coefficient changes, and there is a problem that the coolant at the planned flow rate does not flow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the flow rate of the coolant in the control rod guide tube is adjusted to an appropriate amount so that a stable flow rate distribution can be obtained. An object of the present invention is to provide a cooling structure for a control rod for a high-temperature gas-cooled reactor that does not hinder the freedom of swinging, rotating, and vertical directions.

[0012]

According to a first aspect of the present invention, the upper portion of the control rod guide tube is fixed by an upper bundle, and the upper bundle is supported by a guide tube support member. In the cooling structure of a control rod for a high-temperature gas furnace, in which a coolant flows from the upper end of the control rod guide tube to the inside through the space between the upper bundle, the flow rate of the coolant is adjusted to the upper bundle. It is characterized by having an inflow hole.

According to a second aspect of the present invention, a guide cover is provided so as to penetrate substantially the center of the guide tube supporting member, and the guide cover is fitted to the upper end of the control rod guide tube. I do. Thus, it is possible to restrict the inflow of the coolant from other than the inlet hole.

According to a third aspect of the present invention, a gap is provided in a fitting portion between the guide cover and the control rod guide tube, and a slide plate for restricting the flow of coolant through the gap is provided on the outer peripheral surface of the guide cover. It is characterized by becoming. This enables the control rod guide tube to swing, rotate, and vertically move.

According to a fourth aspect of the present invention, the slide plate is provided on the guide cover at a position following the vertical movement of the control rod guide tube and in contact with the upper end surface of the upper bundle plate. It is characterized by.

According to the present invention, a guide cover projecting from the lower surface of the control rod driving device and a slide plate following the operation of the control rod guide tube eliminate the flow of the coolant from the through portion of the upper surface of the guide tube, and provide control. An inflow hole for adjusting the inflow amount of the coolant is provided at the upper end of the rod guide tube. Thus, the flow rate of the coolant flowing through the control rod guide tube and the control rod insertion hole can be arbitrarily adjusted, and a stable flow rate distribution independent of the installation position of the control rod guide tube can be obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling structure for a control rod for a high-temperature gas furnace according to the present invention will be described with reference to FIG. In addition,
FIG. 1 corresponds to FIG. 4, and since the configuration for the high-temperature gas furnace is the same as in FIGS. 2 and 3, the description thereof is omitted.

In FIG. 1, a plurality of control rod guide tubes 15 (only one is shown in FIG. 1) are fixed at the upper end with an upper bundling plate 20 similarly to the conventional structure shown in FIG. It is suspended on the guide tube support portion 14 via the plate 20 so as to be vertically movable and swingable. The upper bundling plate 20 has a coolant inflow hole 21 separately from the wire rope penetration portion 19 through which the wire rope 18 passes.
Is provided.

A guide cover 23 is provided below the control rod driving device (not shown). The guide cover 23 penetrates the guide tube support member 14 and is formed on the upper bundle plate 20 by a wire rope penetrating portion 19. Is fitted. The fitting portion has an appropriate clearance so as not to hinder swing of the control rod guide tube 15 and movement in the rotation direction.

Then, a slide plate 22 large enough to fill the gap between the penetrating portion 19 and the guide cover 23 is provided on the outer peripheral surface of the guide cover 23 so that there is no leakage flow from the gap. The slide plate 22 is configured to follow the vertical movement of the control rod guide tube 15 using the guide cover 23 as a guide.

Next, the operation of the embodiment according to the above configuration will be described. The coolant flows from the inside of the furnace vessel 1 shown in FIG. 3 to the space between the control rod guide tube support portion 14 and the upper bundling plate 20, and flows from the inflow hole 21 provided in the upper bundling plate 20 shown in FIG. Guide tube
15 flows downward, but since the wire rope penetration portion 19 is closed by the slide plate 22 and the guide cover 23, the amount of the coolant flowing into the control rod guide tube 15 is controlled by arrows. As shown in FIG.

Therefore, the flow rate of the coolant can be arbitrarily adjusted by changing the size of the inflow hole 21. In addition, since the inflow holes 21 are independently installed without penetrating objects or the like, the distribution of the coolant flow rate is not affected by the installation posture of the control rod guide tube 15.

Further, even if the control rod guide tube 15 is swung, rotated, and moved up and down as in the prior art, a slide plate for preventing the leakage flow to the gap caused by the movement is provided.
The function of 22 does not change the coolant flow distribution.

In the present embodiment, the guide cover
Even if a flexible bellows or the like is installed between the inside of the guide tube support member 14 located at the lower part of the control rod drive device and the upper bundle plate 20 instead of the slide plate 23 and the slide plate 22, This has the effect of preventing the coolant from leaking from the air.

[0025]

According to the present invention, the flow rate of the coolant flowing into the control rod guide tube can be adjusted to an appropriate amount and a stable flow distribution can be obtained. It does not impede the freedom of rotation and vertical direction.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a cooling structure of a control rod for a high-temperature gas reactor according to the present invention.

FIG. 2 is a longitudinal sectional view schematically showing a configuration of a high-temperature gas furnace related to the related art and the present invention.

FIG. 3 is a longitudinal sectional view showing a configuration of a control rod drive system of a conventional high temperature gas furnace.

FIG. 4 is a longitudinal sectional view showing a cooling structure of a conventional control rod for a high-temperature gas reactor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Furnace container, 2 ... Core, 3 ... Core support member, 4 ... Stand pipe, 5 ... Control rod drive, 6 ... Outer tube, 7 ... Lower plenum, 8 ... Gap, 9 ... Upper plenum, 10 ... High temperature Plenum, 11 ... inner tube, 12 ... hearth, 13 ... control rod insertion hole, 14 ...
Guide tube support member, 15 ... control rod guide tube, 16 ... control rod, 17 ...
Connection member, 18: wire rope, 19: wire rope penetration, 20: upper bundling plate, 21: inflow hole, 22: slide plate, 23: guide cover.

Claims (4)

[Claims] An upper portion of a control rod guide tube is fixed by an upper bundle plate, and the upper bundle plate is supported by a guide tube support member, and the control rod guide is passed between the guide tube support member and the upper bundle plate. In the cooling structure of a control rod for a high-temperature gas furnace in which a coolant flows from an upper end of a pipe, an inflow hole for adjusting a flow rate of the coolant is provided in the upper bundling plate. Cooling structure for gas furnace control rods. 2. The control rod guide tube according to claim 1, wherein a guide cover is provided through substantially the center of the guide tube support member, and the guide cover is fitted to an upper end of the control rod guide tube. Cooling structure for control rods for HTGR. 3. A guide plate, wherein a gap is provided in a fitting portion between the guide cover and the control rod guide tube, and a slide plate for restricting inflow of coolant from the gap is provided on an outer peripheral surface of the guide cover. The cooling structure for a control rod for a high-temperature gas reactor according to claim 1. 4. The guide cover according to claim 1, wherein said slide plate is provided on said guide cover at a position following said vertical movement of said control rod guide tube and in contact with an upper end surface of said upper bundling plate. 2. A cooling structure for a control rod for a high-temperature gas-cooled reactor according to 1.