JPS63150693A - Fuel exchanging mechanism of nuclear reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Industrial Application Field This invention relates to a nuclear reactor fuel exchange mechanism intended for fast breeder reactors.

[Conventional technology]

As is well known, in the above mentioned nuclear reactor, the upper core mechanism including the fuel exchanger and control rod drive device is installed in a rotating plug placed on the top of the reactor vessel. The system is configured to access the system to perform fuel exchange, control rod drive operations, etc.

Conventionally, the access method in this case is as shown in Fig. 3 (al.
~(d+ Various methods are known. In the figure, 1
2, 3.4 are rotary plugs, 5 is a core upper mechanism, 6 is a fuel exchanger, 6a is an offset arm of the fuel exchanger, 6b
1 shows a hold-down mechanism equipped with a grip supported at the tip of the offset tore 1, 6a. Here, the FA1 diagram shows a system that combines a single-rotation plug and an offset arm type fuel exchanger.

Cb1 diagram shows double rotation plug and offset arm type 12!
A method that combines a toll exchange machine.

The fc1 diagram shows a system that combines a double rotating plug and a direct acting fuel exchanger.

(di U!J is a system that combines a triple rotating plug and a direct-acting fuel exchanger.

el+ e2. in the figure. e3 is the eccentricity between the core one-turn plug and the refueling machine, L is the offset amount of the old refueling machine, d is the outer diameter of the outermost rotating plug, and D is the reactor vessel (not shown) that houses the core. Represents the minimum required radius.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned various systems, when designing, the fuel exchanger 6 (the hold-down mechanism at the tip of the offset arm in an offset arm type fuel exchanger) can access all positions of the reactor core 1, and the upper core mechanism 5. fuel exchange machine 6
．． It is also necessary to set the dimensions of each device and its layout conditions so that the bearing stands of the rotating plugs 2 to 4 do not interfere with each other. For example, in the system (5) in which a single rotation plug and an offset arm type fuel exchanger are combined, first, the upper core mechanism 5 and the fuel exchanger 6, which are installed side by side on the rotating plug 2, are connected to the offset arm 6a of the fuel exchanger. In order to prevent the movement locus and the upper core mechanism 5 from interfering with each other, it is necessary to install the two with a sufficient distance between them, and for this reason, the required outer diameter dimension d of the rotating plug 2 becomes large, and In order to allow the refueling machine to access the central region of the core 1, the amount of eccentricity between the center of rotation of the rotary plug 2 and the center of the core 1 inevitably becomes large.

In other words, in the conventional method described above, when the outer diameter of core l = j method is determined, the outer diameter of the outermost rotating plug, the amount of eccentricity from the core center, etc. are necessarily uniquely determined, and these dimensions is limited by the interference avoidance conditions between the upper core mechanism 5 and the fuel exchanger 6, as described above, and as a result, the diameter of the reactor vessel housing the reactor core 1 becomes significantly larger than the outer diameter of the core. This is a major obstacle in making the entire nuclear reactor smaller and more compact.

The purpose of this invention is to provide a cleverly constructed reactor that can reduce the outer diameter of the reactor vessel and make the entire reactor smaller and more compact while satisfying the conditions for avoiding interference between the fuel exchanger and the upper core mechanism. The purpose is to provide a fuel exchange mechanism for nuclear reactors.

Means for Eliminating Problem C] In order to solve the above problem, according to the present invention, the core upper mechanism and the extended The offset arm type refueling machine equipped with is mounted side by side, and a notch space is formed in the inner body of the core upper mechanism in the part facing the fuel exchanger, reaching from the circumferential surface to the central part of the river. The fuel exchanger is configured to access a designated position on the core side and perform fuel exchange by a combination of the rotation operation of the plug, the rotation of the fuel exchanger, and the extension and contraction operation of the arm.

[Operation] With the above configuration, during normal reactor operation, the upper core mechanism performs necessary operations such as driving control rods to the reactor core. On the other hand, during refueling, the rotation of the single-rotation plug and the extension/retraction operation of the five rotating arms of the refueling machine are used to position the reactor at a designated position on the core side, and the telescopic arm is used to access the core center. By extending the hold-down mechanism and entering the notch space formed in the inner body of the core upper mechanism, it becomes possible to access all positions on the core side and perform fuel exchange.

[Embodiment] FIGS. 1 and 2 show a fuel exchange mechanism for a nuclear reactor according to an embodiment of the present invention, and the same members corresponding to FIG. 3 are given the same reference numerals. That is, the upper surface of the reactor vessel 7 housing the reactor core 1 is provided with a fixed plug 8 and a single-rotation plug 2, and the rotating plug 2 is equipped with a core upper mechanism 5.
．． A retractable arm type offset arm type refueling machine 6 is mounted close to the cough core upper mechanism 5.

Describing the structure of the fuel exchanger 6 here, the fuel exchanger includes a main body shaft portion 6c mounted and supported on the rotary plug 2, a telescopic arm 6a as an offset arm that projects laterally from the main body shaft portion 6C, and a retractable arm 6a as an offset arm. Gripper 6 attached to the tip
It consists of a hold-down mechanism 6b equipped with d, and a drive part 6e equipped on the outside of the furnace shaft of the main body.By operating the drive part 6e, the main shaft part 6C rotates (in the direction of arrow A) and the telescopic arm 6a extends and contracts. (in the direction of the arrow), lifting and lowering of the hold-down mechanism 6b.

The gripper 6d is raised and lowered (in the convex direction of the arrow), and the grip and collar claws are opened and closed.

On the other hand, in the core upper mechanism 5, a body 5a is provided at a portion of the core inner body 5a facing the fuel exchanger 6.
A radial cutout space 5b is formed so as to reach the center of the cylinder from the circumferential surface of the shell.

This cutout space 5b is for allowing the hold-down mechanism 6b of the fuel exchanger 6 to enter when the fuel exchanger 6 accesses the central region of the core 1 during fuel exchange as will be described later.

Further, the rotating plug 2 is supported by a bearing stand 2a, and is rotated in two directions shown by arrows (FIG. 2) by a drive device (not shown). Further, numeral 9 indicates a fuel relay mechanism in the furnace which serves as a fuel inlet/outlet relay point, and 10 indicates a fuel inlet/outlet passage passing through the fixed plug 8. The illustration shows a state in which the hold-down mechanism of the fuel exchanger 6 is operated to enter into the notch space 5b of the upper core mechanism 5 to access the central region of the core 1.

Next, the operation of the nuclear reactor fuel exchange mechanism having the above configuration will be explained. First, during operation of the nuclear reactor, the core upper mechanism 5 is positioned relative to the reactor core 1 by rotating the rotary plug 2, and in this state, the control rod driving device is operated to drive the control rods from the reactor upper side.

On the other hand, during fuel exchange, the designated fuel exchange position on the core side is accessed by a positioning operation by rotating the rotary plug 2 and moving the main body shaft 6d of the fuel exchanger 6 and the telescopic arm 6a, and at this position, the hold-down mechanism is activated. 6
b. Operate the gripper 6C to exchange fuel. Here, in particular, when the hold-down mechanism 6b of the fuel exchanger is to access the central region of the core 1 located on the lower surface of the core upper mechanism 5, the telescopic arm 6a is once folded toward the main body shaft side so as to retract. Then, the main body shaft 6d is rotated so that the hold-down mechanism 6b faces the notch space 5b opened in the circumferential surface of the body 5a of the upper core mechanism 5, and the telescopic arm 6a is extended from there by the required offset amount. As shown in the figure, cut out the hold-down mechanism 6b and insert it into the space 5.
Enter into C. In addition, in order to receive and transfer fuel between the fuel exchanger 6 and the fuel relay mechanism 9 inside the reactor, the telescopic arm 6a is once retracted from the illustrated position and the hold-down mechanism 6b is moved outside the body of the upper core mechanism 5. After pulling out the main body shaft 6d and rotating the main body shaft 6d by 180 degrees, the telescopic arm 6a is extended to the position of the in-furnace relay mechanism 9 to receive and transfer the fuel. In this way, fuel exchange [6 is all positions on the core 1 side,
The in-furnace relay mechanism 9 can be accessed at any position. The accessible range of the fuel exchanger 6 is shown in FIG. 2 by a shaded area A.

Further, according to the above configuration, the upper core mechanism 5 and the fuel exchange tA
It is possible to mount the upper core mechanism 5 and the fuel exchanger 6 close to each other on the single rotating plug 2 while avoiding interference with the rotating plug 2. Therefore, the outer diameter dimension d of the rotating plug 2 can be It can be reduced to a circumscribed circle including the main bodies of the upper core mechanism 5 and the fuel exchanger 6 that are close to each other, and the fuel exchanger 4
i! The amount of eccentricity between the center of the core and the center of rotation of the single-rotation plug 2, which is required to access the central region of the reactor core 1, can be accommodated with a small amount of eccentricity. The diameter dimension D (FIG. 1) can be significantly reduced compared to the various conventional methods described in FIG.

〔Effect of the invention〕

As described above, according to the present invention, an upper core mechanism and an offset arm type refueling machine equipped with a telescoping arm are mounted in parallel to each other in close proximity to the single-rotation plug provided on the upper surface of the reactor vessel. A notch space is formed in the inner shell of the mechanism in the part facing the fuel exchanger that reaches from the circumferential surface to the center of the shell, and is used to rotate the single-rotation plug.

By combining the rotation of the fuel exchanger and the extension/retraction operation of the arm, the fuel exchanger is configured to access a designated position on the core side to perform fuel exchange, allowing the simple single-rotation plug system to connect the upper core mechanism and fuel exchange mechanism. In addition to reducing the outer diameter of the rotating plug to 6 ftm compared to conventional methods, the required outer diameter of the reactor vessel is significantly reduced, making the overall reactor configuration smaller and more compact. can be achieved.

[Brief explanation of the drawing]

Fig. tta is a vertical sectional view showing a fuel exchange mechanism for a nuclear reactor according to an embodiment of the present invention, Fig. 2 is a plan layout diagram of Fig. 1, and Fig. 3 is a schematic plan layout showing fuel exchange mechanisms according to various conventional methods. In the figure, fal is a diagram showing a combination of a single-rotation plug and an offset arm type fuel exchanger, (hl is a diagram showing a combination of a double-rotation plug and an offset-arm type fuel exchanger, and tel is a diagram showing a combination of a double-rotation plug and an offset-arm type fuel exchanger. A diagram showing a system in which a plug and a direct-acting refueling machine are combined, (di is a diagram showing a system in which a triple rotating plug and a direct-acting refueling machine are combined. In each diagram, 1: core, 2: Single rotation plug, 5: Core upper mechanism, 5a
: Furnace inner body, 5b=notch space, 6: Fuel exchanger, 6
a: telescopic arm, 6b: hold-down mechanism, 6c nigerippa, 6d: main body shaft, 7: furnace vessel. ,・de-1, Hema J-Masshi Yamaguchi a \・, ,I 1st
Figure 2

Claims (1)

[Scope of Claims] 1) A core upper mechanism and an offset arm type refueling machine equipped with a telescoping arm are mounted in close proximity to each other on a single-rotation plug provided on the upper surface of the reactor vessel, and the reactor core upper mechanism is The inner body has a cutout space extending from the circumferential surface to the center of the body at the part facing the fuel exchanger, which allows the rotation of the single-rotation plug and the rotation of the fuel exchanger.
2) A nuclear reactor fuel exchange mechanism characterized in that the fuel exchange machine is configured to access a designated position on the core side and perform fuel exchange by a combination of arm extension and contraction operations.2) A nuclear reactor fuel exchange mechanism according to claim 1. The upper structure consists of a main body shaft in which the fuel exchanger is mounted and supported by a rotating plug, a telescoping arm projecting laterally from the main body shaft, and a hold-down mechanism equipped with a gripper attached to the tip of the arm. A nuclear reactor fuel exchange mechanism characterized by