JPS58153200A - Failed fuel detecting device - 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 [Technical Field of the Invention] The present invention relates to a damaged fuel detection device for inspecting fuel taken out of the reactor pressure vessel in a water-cooled nuclear reactor such as a boiling water reactor. Regarding.

[Technical background of the invention and its problems]

Fuel assemblies loaded in the core of a nuclear reactor must be periodically inspected for damage.

To perform this inspection, the reactor must be periodically shut down, the fuel assembly taken out from the core, and inspected using a damaged fuel detection device in water in a pool such as a fuel storage pool.
I'm confused.

A conventional damaged fuel detection device is configured as shown in FIG. 1, for example. That is, the fuel assembly C is inserted from above into the container B placed below the cooling water level A, and then the opening/closing body B is closed using an operating pole or the like from above the floor.

For tightening, the arm R is vertically erected, and then the operator tightens the opening/closing body E by rotating the pole G using an operating ball or the like while visually observing from below the water surface. after that,
After the pump H is driven to forcefully circulate the chimple water in the container B for a certain period of time, sample water is taken out through the sampling pipe I and sent to the detection system J for analysis to detect damaged fuel.

As described above, in the conventional device, the opening, closing and tightening work of the opening/closing body E is done manually under the water surface, and requires a great deal of work because it is deep underwater, for example at a depth of around 7m, and requires detailed manual work that relies on visual inspection. It takes effort and time. Moreover, there is a problem of radiation exposure for the workers because the time spent visually observing on the water surface is long, and if there are ripples or light reflections on the water surface A, it becomes extremely difficult to see visually, making it difficult to carry out work quickly.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to use a shutter as an opening/closing body for opening and closing a fuel inlet/outlet, and to automatically open/close and seal the shutter by remote control after inserting a fuel assembly into a container. It is an object of the present invention to provide a damaged fuel detection device that can quickly and efficiently collect sample water and reduce radiation exposure to workers.

[Summary of the invention]

In other words, the present invention provides a container installed in pool water outside the reactor pressure vessel, for example, underwater in a spent fuel storage pool, a shutter provided at the fuel inlet/outlet at the upper end of the container, and a shutter that can be opened and closed by air pressure, for example. a cylinder mechanism for driving, a hollow elastic packing annularly provided around the fuel inlet/outlet, a mechanism for supplying pressurized fluid, such as compressed air, to the hollow elastic packing when the shutter is closed; This damaged fuel detection device is equipped with a circulation mechanism that forcibly circulates the water inside the container, and a sampling pipe that takes out the sample water after circulation and sends it to the detection system.

Therefore, the shutter can be opened and closed by remote control using the upper ring mechanism, and when the closed state of the shutter is detected, pressurized fluid is sent into the hollow elastic packing to expand it and automatically open the fuel inlet/outlet. Since it can be sealed, preparations for sample water collection can be completed quickly.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4. In FIG. 2, 1 is a container. This container 1 is a reactor pressure vessel (not shown)
□It is designed to be installed in an external pool, for example, in the pool water of spent fuel storage boule 2. Further, the container 1 has a cylindrical container main body part 1a that can vertically accommodate the fuel assembly C therein, and a leg part 1b and a circulating water introduction part 3 at the lower part of the container body part 1a. A drain valve 4 and the like are provided.

On the other hand, the E part of the container body 1 is provided with a head IC having a fuel inlet/outlet 5 opened at one end surface, and this head IC has a plate-shaped shutter for opening and closing the fuel inlet/outlet 5. 6 is provided movably in the horizontal direction. This shutter 6 is adapted to slide along a shutter guide 7. Further, a shutter drive rod 8 is connected to one end of the shutter 6, and this shutter drive rod 8 is connected to the rond 10m of the cylinder mechanism 10 via a connection plate 9. The cylinder mechanism 10 is arranged horizontally, and its cylinder body 10b is fixed to the head IC. Therefore, when the Rondo IOa expands and contracts, the shutter drive rod 8 moves in the same direction, and the shutter 6 opens and closes in the horizontal direction.

The cylinder body 10b also has an air supply pipe 12.1 for supplying and exhausting fluid for driving the rod, such as compressed air.
3 are connected, and these air supply pipes 12 and 13 are each connected to a switching valve 14. And this switching valve 14
An air pipe 15 and an exhaust pipe 16 are connected to the air pipe 1.
5 is connected to compressed air #20 via a pressure needle 17 and a pressure reducing valve 18.

Further, a sample water outlet 21 is provided at approximately the central portion 1' of the shutter 6, and this sample water outlet 21 is connected to the suction side of a pump 23 via a water pipe 22. This pump 231 is equipped with a timer 24. Further, the discharge port of the pump 23 is connected to the flow needle 25 and the on-off valve 2.
6, and is connected to the water pipe 27 through the water pipe 27.
The other end side is connected to the circulating water inlet 3 described above.

That is, these water pipes 22, 27 and pump 23
, a flow meter 25, an on-off valve 26, and the like constitute a circulation mechanism 28 for forcibly circulating water within the container I.

7. Then, on the upstream side of the on-off valve 26, the sampling pipe 3 is opened.
0 is branched. This sampling pipe 30 is connected to a detection system 33 via an on-off valve 32 equipped with a timer 31.

This detection system 33 has a function of analyzing radioactive nuclides and radionuclides contained in the sample water to detect the presence or absence of damaged fuel.

Further, an annular hollow elastic packing 35 is arranged around the fuel inlet/outlet 5. This hollow elastic packing 35 is fitted and held in a packing accommodation groove 36 formed in an annular shape in the sub-valve of the fuel inlet/outlet 5, and has an air chamber 9 inside.
5a, and has an air supply/exhaust port 38 that communicates with the air chamber 35a. And this air supply and exhaust 1
A supply/exhaust pipe 39 is connected to 38 . This supply and exhaust pipe 3
9 is connected to the compressed air #20 described above via an on-off valve 4I equipped with a timer 40, a pressure 142, and a pressure reducing valve 43.

Further, an exhaust opening/closing valve 46 equipped with a timer 45 is connected to the sending/exhausting pipe 39 .

And these on-off valves 41, 46, pressure reducing valve 43, timer 4
0.45 etc., constitutes a mechanism 41 that supplies pressurized fluid (compressed air) to the hollow elastic packing J5.

In addition, each of the above-mentioned on-off valves 26, 32, 41, 46
Both of the switching valves 14 and 14 are of the 'magazine type'.

Further, a shutter 6 is provided near the fuel inlet/outlet [''5].
A limit switch 50 is provided for detecting that the on-off valve 41 is closed.
．． 46 to output a signal S.

Next, the operation of the apparatus of the F period embodiment will be explained.

First, operate the switching valve 14 to send compressed air from the compressed air $20 to the cylinder mechanism 10 through the air pipe 12 I),
Extend the rod lOa.

This opens the shutter 6, making it possible to insert the fuel assembly C. Next, after inserting the fuel assembly C taken out from the reactor core into the container 1, the switching valve 14 is operated to send compressed air into the other air supply pipe 13, the rod Ioa is retreated, and the shutter 6 is closed. At this time, the hollow elastic packing 35 is in a contracted state because the on-off valve 46 for exhausting the hollow elastic packing is open and in the exhaust state. Therefore, the opening/closing operation of the shutter 6 is not hindered.

When the shutter 6 is closed, the limit switch 5
0 senses this and sends the signal 51 to the on-off valves 41 and 46 to open the air supply on-off valve 41 and close the exhaust on-off valve 46. This series of operations sends compressed air to the hollow elastic packing 35, and the pressure causes the hollow elastic packing 35 to expand. Therefore, the space between the 'C shutter 6 and the fuel inlet/outlet 5 is sealed. At the same time, the timer 40 of the on-off valve 4 is activated, and after a certain period of time has elapsed, the timer 40 outputs a signal S (reduced in FIG. 4) to the on-off valve 26', J2. Then, the sample water circulation on-off valve 26 is opened, and the water sampling on-off valve 32 is closed, completing preparations for circulating the water in the container 1.

Next document=, Signal 81 indicating the completion of operation of the above-mentioned on-off valves zg and sz
+84 is sent to pump 23, pump IS is activated, and timer 24 of this pump is activated. As a result, water in the container 1 is taken out through the water pipe 221 through the sample water outlet 21 at a flow rate adjusted in advance with the flow needle 25, and through the on-off valve 161 and the water pipe 2r into the circulating water inlet S.
Then, it is returned to the container 1 and forced to circulate for a certain period of time.

After a certain period of time has elapsed, the timer 24 is activated and a pump stop signal 8. is output and pump j3 stops. Next, a signal 8° indicating that the pump has stopped is sent to the on-off valves zg, sz+:, the circulation on-off valve 26 is closed, the water sampling on-off valve 32 is opened, and the sample water is detected through the sampling pipe 30. Sent to system 33.

Next 1: Due to the action of the timer S1 of the on-off valve 12, after a certain period of time, the sample water collection completion signal 8 is sent to the on-off valve 41.
．． 46, the air supply on-off valve 41 closes and the exhaust on-off valve 46 opens, and the compressed air in the hollow elastic packing 35 is discharged. At the same time, the timer 45 of the on-off valve 46 is activated, and after a certain period of time, the timer 45 is activated.
The switching valve 14 (: switching signal S) is sent, and compressed air is sent to the cylinder mechanism 10 in the direction of opening the shutter 6. Therefore, the shutter 6 is opened again.

When the inspection for damaged fuel on one fuel assembly C is completed as described above, the fuel assembly C is taken out from the container 1 by a fuel gripping member (not shown). After the container 1, water pipes 22, 27, etc. are washed with pure water, the next fuel assembly is inspected using the same procedure as above.

As described above, according to the device of this embodiment, not only can the shutter 6 be opened and closed automatically by remote control, but also a series of sample water collection operations can be automated by sequentially controlling each opening/closing valve and timer. The labor required by workers is significantly reduced compared to conventional methods. Moreover, since most of the work does not rely on visual inspection, it is extremely effective in reducing radiation exposure to workers.

In addition, a shutter I that moves horizontally with respect to the fuel intake/outlet eye 5 is adopted, and this shutter 6 is also driven to open and close by a cylinder mechanism 1-1 that also extends and contracts in the horizontal direction, so the mechanism required for opening and closing is It is extremely simple and can be miniaturized, and its operation is also simple. Therefore, it has few failures and can operate reliably even in reactor water with high reliability.

1. A common compressed air l11 is used as a gas supply source for the drive of this cylinder mechanism 10 and the hollow elastic packing J5.
Since 0 is used, the configuration is simplified and a part of the piping system can be shared.

In this embodiment, compressed air is used as the pressurizing fluid for the cylinder mechanism 1o and the hollow elastic packing J5.
Other types of gases or liquids may also be used.

In addition, as shown in Fig. 5, a small air cylinder mechanism 1
By providing a pair of 0.10, the entire device may be further miniaturized. In this case, rods 10m and 10m are connected to the left and right sides of the connecting plate 9, but since the basic structure and operation are the same as in the previous embodiment, common parts will be given the same reference numerals and explanations will be omitted.

〔Effect of the invention〕

As described above, the present invention (2) allows the shutter to be automatically opened and closed by remote control using a cylinder mechanism;
In addition, when the shutter is closed, pressurized fluid is sent into the hollow elastic packing to expand it and automatically seal the fuel inlet, making remote automation possible and greatly reducing the labor required for the work. Furthermore, since the work that relies on visual inspection is greatly reduced compared to the conventional method, it is extremely effective in reducing the radiation exposure of workers, and has the great effect of allowing damaged fuel detection work to be carried out safely and quickly.

[Brief explanation of the drawing]

No. iml is a configuration diagram of a conventional damaged fuel detection device. FIGS. 2 to 4 show an embodiment of the present invention, and FIG.
IA detects damaged fuel! FIG. 3 is a plan view of the container portion, and FIG. 4 is a flowchart showing the flow of signals during damaged fuel detection work. FIG. 5 is a plan view showing a modified example of the cylinder mechanism portion. DESCRIPTION OF SYMBOLS 1... Container, 2... Pool, 5... Fuel inlet/outlet, 6... Shutter, 10... Cylinder mechanism,
10... Compressed air source, 28... Circulation ffi mechanism, 30
...Sampling tube, JJ...Detection system, 35...
Hollow elastic packing, 47... pressurized fluid supply mechanism, C.
...Fuel assembly. Patent attorney Suzue Takehiko Figure 5 10 1 (Ja

Claims (1)

[Claims] (11) A shutter installed in the pool water outside the reactor pressure vessel, a shutter provided at the fuel inlet/outlet, a V9 shutter mechanism for driving the shutter to open/close, a hollow elastic packing that is continuously disposed and expands and contracts by introducing and removing pressurized fluid therein;
A mechanism that supplies pressurized fluid to the hollow elastic gasket when the shutter is closed, a circulation mechanism that forcibly circulates the water in the container after the shutter is closed, and a detection system that takes out the sample water after circulation. A damaged fuel detection device characterized by comprising a sampling tube for sending the fuel to the fuel tank. (2) A patent claim characterized in that the shutter is provided to be movable in the horizontal direction with respect to the fuel inlet/outlet opening, and the cylinder mechanism is connected to the shutter through a rod, and the cylinder body is connected to the container body. The damaged fuel detection device according to scope (1). (3) A common compressed air source is used as a power source for the cylinder mechanism and a fluid supply source for the hollow elastic packing.
Damaged fuel detection device described in section 2).