JPS59203995A - Fuel assembly inspection table - 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 The present invention mainly involves maintaining a nuclear fuel assembly in a pool during periodic inspections, especially when inspecting the health of each component that constitutes the assembly. This relates to an inspection stand.

The nuclear fuel assembly consists of irradiated spent fuel (5pent Fu
el (hereinafter referred to as S and F) is reloaded into the reactor and its integrity is inspected before reuse, and it is subjected to various periodic inspections to confirm whether reuse is possible, leakage inspection, and assembly. Accuracy of each fuel rod gap in the body.

The health of each fuel rod support grid, the bending of the assembly, and other components that make up the assembly are detected using various detection devices such as underwater televisions and various sensors, and the detected data is sent to each inspection device. We send them for visual inspection and measurement.

Conventionally, each inspection and measurement in such periodic inspections has been carried out by installing a spent fuel handling tool (1) as shown in FIGS. 1 and 2, and using this tool (1) to handle the spent fuel
S, F) (3) is being inspected in a suspended state, and tools are being handled using a bridge crane (2).
It was carried out by

In this test, since S and F have high radioactivity,
This is carried out by underwater remote control using pools (4) such as spent fuel storage pools (S, F, P) or cask loading pools (0, L, P), as shown in Figures 2 and 4. S, F (3) a: The suspended handling tool (1) is held on the pedestal 01) while suspended from the bridge crane (2), and the vertically movable underwater lighting (8) and underwater television camera are installed. (9) etc. are placed near the suspended S and F (3), and the images that have passed through the mirror part (9) are captured by the underwater television camera (9).
) and projected it onto a television monitor screen (10) that includes the control equipment on the ground.

At this time, for one underwater TV camera (9) (hereinafter abbreviated as underwater TV), the handling tool (1) and s
, p, (a) exists in two groups (see Figure 4), one S,
When inspecting F, other S and F were moved and replaced to improve inspection efficiency.

The underwater TV (9) can be moved up and down by the drive unit M (12), and as shown in Figure 4, the center of rotation (
llj) It was possible to arbitrarily select the illustrated positions A and B as the center.

However, as mentioned above, inspecting S, F, (3)i while suspended in water is difficult to hold S, F, (3) correctly underwater, and is difficult to handle. As a result, a situation has arisen in which inspections cannot be carried out accurately and stably, so in recent years there has been a movement to improve and automate the handling of spent fuel itself. , L, P, Attempts have been made to install manipulator cranes in the area.

As shown in Figure 3, this manipulator crane (5) method does not use spent fuel handling tools, and the crane itself has an outer cylinder (6) and an inner cylinder (7). There is an assembly holding part in the holder, which suspends S, F, (3) and slides S, F, along with the inner cylinder (7) inside the outer m (6), and attempts to move it up and down. It is something.

However, as mentioned above, this manipulator crane (5) does not use spent fuel handling tools or the conventional bridge crane f: because it handles S, F, 'i using the outer cylinder and inner cylinder. Inspection methods cannot be adopted, and a special fuel mount structure is desired to hold the fuel assembly and perform visual inspection.

In view of the above-mentioned circumstances, the present invention focuses on enabling the use of a manipulator crane and more accurate inspection, and provides a fuel inspection stand in which a modification is added to the deep holding member of the fuel assembly. The purpose is to

That is, the present invention is characterized by a holding frame that supports the lower part of the fuel assembly and loosely holds the upper part, and does not hold anything other than the upper and lower parts, and the lower holding member is linked to a rotational drive device so that it can be rotated. The key point is that the fuel assembly held as a fuel assembly can be rotated.

Here, the lower support member of the fuel assembly may be a normal support member rotatably installed on the holding frame, or it may further have support bins at diagonal positions and provided on the bottom of the lower nozzle of the fuel assembly. It may also be made to fit into the support pin fitting hole and be held more stably.

Further, the upper holding member may be a holding frame that holds the upper nozzle of the fuel assembly, or may be a clamping device, in which the former leaves a slight gap between the upper nozzle and the upper nozzle. It is most preferable that the frame holding and clamp holding can be arbitrarily selected.

On the other hand, it is preferable that the fuel assembly, the underwater lighting, and the underwater TV are movable relative to each other, and for that purpose, it is desirable that they be movable vertically in the vertical direction. Of course, in this case, both must be movable relative to each other, and if the fuel assembly rotates and does not move vertically, underwater lighting and underwater T
``It is important that the V etc. can move up and down, and if underwater lighting and underwater TV are to be fixed, it is important that the fuel assembly can be moved up and down.

In addition, considering the replacement of damaged fuel rods, the holding position of the upper holding member is preferably held not only at the upper nozzle position but also at the top grid position. Therefore, it is useful to be able to select between frame holding and clamp holding as described above. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the inspection stand of the present invention will be further described with reference to the accompanying drawings.

FIG. 5 shows an example of the inspection frame of the present invention, which is used for temporarily placing the fuel assembly and rotating the assembly including the drive device when carrying out visual inspection of the fuel assembly. A certain manibrake crane and vertical movement mechanism are omitted from the illustration.

In the figure, (13) is the holding frame, (1→(10 is the assembly being inspected!), (15) is the assembly rotation drive shaft, and these constitute the main parts of the frame of the present invention.
There are underwater lighting (8) and underwater TV near the assembly (3) of 3).
(9) and an automatic inspection/measurement sensor (16) are integrally arranged so as to be movable up and down, including a portion of the mirror (9).

The assembly rotation mechanism in the above-mentioned mount of the present invention includes an assembly rotation device 04) which is installed on the ground and includes a drive source such as a motor, and the device 0 is connected via a bevel gear or the like (not shown). A drive shaft (15) to be driven, a pair of bevel gear mechanisms (17) consisting of a bevel gear provided at the lower end of the drive shaft 05 and a bevel gear meshing with the bevel gear, and a pool to which power is transmitted from the bevel gear mechanism. Internal rotation device (pair of bevel gear mechanisms 1: +8 in the lower tin), gear (19) of the pool rotation device (14)
) and a gear (20) that is integral with the lower holding member (13a) of the fuel assembly, and by controlling and adjusting the rotation of the drive source, the lower holding member (13
a) Apply the required rotation to the upper fuel assembly (3).

In the illustrated example, the underwater lighting, underwater TV, etc. can be moved between the optical axis lower limit position (solid line) and the upper limit position indicated by the upper two-dot chain line, and the vertical movement mechanism is not particularly shown. However, the captured image is displayed on the TV monitor screen 00) on the ground using a mechanism substantially similar to that shown in FIG. In the figure,
(13b) is an upper holding member.

On the other hand, FIG. 6 shows an example of a mechanism for vertically moving the inspection stand according to the present invention, particularly the holding stand θ3), which has an upper part supported by the bit wall surface (21) and a lower holding part on the bottom. A guide rail (23) is provided on the - side of the fixed pedestal 02), and the movable pedestal (24) moves up and down along the rail (drop) via a rail pulley (25) provided on the - side. are combined in such a way that it can be done.

Then, the wire 0η extending from the winch (26) etc. located on the ground extends downward along the bit wall surface (21), passes through the pulley (28) and bends, and the end thereof is attached to the movable frame (24). It is attached to the pulley (30) and fixed to the same frame, and the wire t27) is attached to the pulley (30) using a winch (26) etc.
When rolling up the movable stand T24) ffi rail (23)
When the tape is unrolled and loosened, it is lowered to approach the fixed frame (22).

, of course U6, here, the rotation mechanism of the fuel assembly lower holding member in the lower holding part is omitted, and only the vertical movement mechanism is shown, and when the rotation mechanisms are combined, both N't
Use together.

Thus, in a preferred embodiment, the inspection stand of the present invention is comprised of the following parts: a fuel assembly holding frame, an assembly rotation device, an assembly up/down device, and an assembly rotation drive device.

Here, the rotation of the assembly is suitable for performing visual inspections over the entire circumference, while the vertical movement of the assembly is suitable for carrying out various inspections and measurements, fuel repairs, and fuel rod replacements with a sensor carriage.

Therefore, the vertical movement range of the assembly is normally close to the entire length of the fuel rod, and rotation may or may not be performed during vertical movement.

In particular, as shown in Figure 4, the fuel assembly holding frame (A)
(B) If the appearance inspection is carried out by installing one set of visual inspection equipment for two inspection frames at both positions, then during the inspection of one aggregate, the other aggregates that have been inspected can be moved and the It is very advantageous to be able to carry out the so-called handling of the test collection in parallel.

Next, a specific example of fuel inspection using the inspection stand of the present invention will be shown.

(1) Visual inspection (underwater TV) Support the fuel assembly with the lower holding member. The upper holding member may be held by either clamp holding or upper nozzle frame holding.

Vertical movement of the assembly (1') When the underwater TV is fixed, the assembly is moved up and down over the entire length of the assembly. Also performs aggregate rotation.

0 mouth) When moving underwater TV, Only rotates the aggregate.

(2) Collective target inspection: Non-contact methods such as external measurement using underwater TV or ultrasonic transmitter/receiver.

As above, the fuel assembly is supported by the lower holding member. The upper holding member is held by the upper nozzle frame with a slight gap. This is because if the upper part is gripped too tightly, the true bending cannot be measured. This has the advantage that, unlike the conventional suspended state, the bending can be measured while the fuel assembly is stationary, which is the state where the fuel assembly is loaded into the reactor.

(3) In addition to the above, we also support fuel repair, underwater periscope inspection, crud measurement, and oxide film thickness measurement.

Various fuel assembly inspections and measurements can be performed such as body outer diameter measurement, γ scan, hold-down spring force measurement, guided simple inner surface inspection, assembly dimension measurement, 8 support grid spring constant measurement, etc.

However, during these inspections and measurements, fuel repairs are performed by clamping the top grid rather than holding the upper nozzle frame. This was done in consideration of the fuel assembly having a structure in which damaged fuel i- can be replaced.In this way, the upper nozzle can be removed by remote control, the damaged fuel rod can be extracted, and it can be replaced with a healthy fuel l:4 rod. Afterwards, you can attach the upper nozzle.

As described above, the inspection stand of the present invention is equipped with members that hold the upper and lower parts of the fuel assembly, and the lower holding member is rotatable and can be moved up and down as necessary. Therefore, unlike the conventional inspection by hanging or nodding, it becomes easy to automate the handling of spent fuel assemblies using a manibrake crane, and the following various remarkable effects are recognized.

(1) Fuel assemblies can be inspected and measured in a stationary state in the same way as when they are loaded into a nuclear reactor, making it possible to carry out more accurate inspections and measurements.

(2) Easily adaptable to manibrake cranes used in spent fuel storage pools.

(3) The assembly can be rotated, moved up and down, and moved for fixed underwater TVs, making it possible to respond reliably.

(4) Inspections can be carried out efficiently by combining the rotation and vertical movement of the assembly, and by using at least two as a set.

(5) Since the fuel assembly is stably held during fuel repair, fuel rods can be easily replaced, improving work efficiency.

(6) Since various inspections and measurements can be easily carried out by providing a sensor carriage etc. which can move vertically relative to the fuel assembly, it is suitable for use as a multi-purpose frame for combinations of various inspections.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic explanatory diagrams showing conventional inspection equipment, Figure 3 is a schematic diagram showing an example of a manipreke crane type inspection equipment to which the present invention is applied, and Figure 4 is an underwater TV and various inspections. FIG. 5 is a schematic view showing the positional relationship with the arrangement of fuel assemblies, FIG. 5 is a front view showing an example of an inspection stand according to the present invention, and FIG. 6 is a schematic view showing an example of a fuel assembly vertical movement device. (3) Spent fuel assembly. (5)・・・・・・Mani break crane. (8)・・・・・・Underwater lighting, (9)・・・・・・
Underwater TV. (9)... Part of Mira, 03)... Holding frame. (13a)...Lower holding member, (13b)...
Upper holding member. 0→04)...Aggregation rotation device, (15)-...
...Drive shaft. (]6)...Sensor for inspection and measurement. Patent applicant Nuclear Fuel Industry Co., Ltd. Figure 1 Figure 7I'2 Figure W3 Figure 4 Leap Figure 5

Claims (1)

[Claims] (1) Holds a spent fuel assembly suspended by a crane in a pool, and has an inspection and measurement sensor carriage that can move vertically relative to the fuel assembly. A mount for holding the spent fuel assembly in a pool in an apparatus for inspecting the appearance etc. of the fuel assembly, the mount including a lower holding member for holding a lower part of the fuel assembly, and a lower holding member for holding an upper part of the fuel assembly. 1. A fuel assembly inspection stand comprising an upper holding member, the lower holding member being interlocked with an assembly rotating device to enable rotation of the fuel assembly held thereon. 2. The fuel assembly inspection stand according to claim 1, wherein the upper holding member of the fuel assembly can arbitrarily select between holding the frame of the fuel assembly and holding the fuel assembly with a clamp. 3. The fuel assembly inspection stand according to claim 1 or 2, wherein the upper nozzle frame position and the upper grid position of the fuel assembly can be arbitrarily selected to hold the upper part of the fuel assembly. 4. The fuel assembly inspection frame according to claim 1, 2 or 3, wherein the inspection and measurement sensor traveling platform moves up and down together with the underwater lighting and the underwater television camera. 5. The fuel assembly inspection frame according to claim 1, 2, 3, or 4, wherein the frame is vertically movable over at least approximately the entire length of the fuel assembly.