KR102630322B1 - Spent nuclear fuel verification equipment - Google Patents

Abstract

The spent nuclear fuel inspection device according to the present invention includes a main body; cable; a radiation detector installed at the end of the cable to detect radiation emitted from spent nuclear fuel; a cable drum installed inside the main body and having the cable wound around its outer circumferential surface; and a rotating member provided in the main body to rotate the cable drum to wind and unwind the cable from the cable drum.

Description

Spent nuclear fuel verification equipment}

The present invention relates to a spent nuclear fuel inspection device, and more specifically, to a spent nuclear fuel inspection device used to detect the presence or absence of spent nuclear fuel used as fuel in a nuclear power plant, etc.

Nuclear fuel refers to materials that are loaded into a nuclear reactor and generate energy through chain nuclear fission, and spent nuclear fuel refers to materials remaining after nuclear fission occurs. This spent nuclear fuel is stored for reprocessing or disposal, and such storage can be divided into on-site storage, intermediate storage, and permanent disposal.

Among the above-mentioned disposal methods, storing spent nuclear fuel in an underwater storage tank requires special attention because the spent nuclear fuel can be used for purposes such as manufacturing nuclear weapons. For this reason, the spent nuclear fuel in the underwater storage tank needs periodic verification, including inspection of the number, and the International Atomic Energy Agency (IAEA) conducts periodic inspections of the spent nuclear fuel stored in the underwater storage tank. .

A radiation detection system is used for periodic inspection of spent nuclear fuel. The radiation detection system measures the radiation emitted by spent nuclear fuel bundles (multiple nuclear fuel rods bundled together) in an underwater storage tank, and calculates the number of nuclear fuel bundles from information on the measured radiation.

An example of such a radiation detection system is disclosed in Korean Patent No. 10-0959783 (see FIGS. 1 and 2).

As shown in FIGS. 1 and 2, the radiation detection system 40 disclosed in the patent is for detecting radiation emitted from a nuclear fuel bundle stored in an underwater storage tank 10. In the underwater storage tank 10, a plurality of nuclear fuel bundles 20 are accommodated on a shelf 21, and the shelf 21 containing the plurality of nuclear fuel bundles 20 is stacked in a plurality of layers in the vertical direction. The plurality of nuclear fuel bundles 20 stacked in this way are arranged in the horizontal and vertical directions of the underwater storage tank 10. Therefore, in order to detect radiation from the nuclear fuel bundle 20 placed at a specific point in the underwater storage tank 10, the radiation detection sensor 110 must be able to move not only in the vertical and horizontal directions, but also in the horizontal and vertical directions. . In particular, since the radiation detection sensor 110 must be inserted into the gap Δd between the nuclear fuel bundles 20 of about 1.5 cm, the radiation detection sensor 110 needs to be slightly moved in the horizontal and vertical directions.

The radiation detection system 40 includes a main body 100, a radiation detection sensor 110 for detecting radiation emitted from the nuclear fuel bundle 20, and a control unit that processes the signal detected from the radiation detection sensor 110. and a cable 130 that transmits the signal detected from the radiation detection sensor 110 to the control unit, and a cable provided in the main body 100 so that the radiation detection sensor 110 can move in the vertical direction of the underwater storage tank 10. A driving unit 140 for transporting the cable 130, a guide device 160 for guiding the transport of the cable 130, a moving unit 180 for moving the position of the main body 100, and a radiation detection sensor ( It includes a fine adjustment unit 200 for finely adjusting the position of 110 (101: cable storage unit, 102: cover).

The moving unit 180 is for moving the main body 100 along the bridge 30, and is provided with a main frame 181 for supporting the main body 100 on the bridge 30 and an upper part of the main frame 181. An upper roller 183 is provided to movably support the main body 100 on the upper rail 31 of the bridge 30, and the main body 100 is attached to the outer side of the upper rail 31 of the bridge 30. It includes an outer side roller 184 that movably supports the main body 100 and an inner side roller 185 that movably supports the inner side of the lower rail 32 of the bridge 30.

The fine adjustment unit 200 includes a first fine adjustment unit 210 for moving the main body 100 in the left and right directions parallel to the moving unit 180, and a direction intersecting the bridge 30, that is, the front and rear direction. It includes a second fine adjustment unit 220 for moving the main body 100.

As a result, the above patent not only makes it easy to install and replace cables, efficiently verify spent nuclear fuel, but also precisely detect the intensity of radiation.

However, in the case of the radiation detection system, it is bulky and heavy, so it is inconvenient to handle and operate, and the sensitivity of the inspection device is low, which reduces the efficiency of inspection.

Therefore, the present invention is intended to solve the problems of the prior art described above, and its purpose is to provide a spent nuclear fuel inspection device that is easy to handle and operate and improves inspection efficiency by improving the sensitivity of the inspection device.

The spent nuclear fuel inspection device according to the present invention includes a main body; cable; a radiation detector installed at the end of the cable to detect radiation emitted from spent nuclear fuel; a cable drum installed inside the main body and having the cable wound around its outer circumferential surface; and a rotating member provided in the main body to rotate the cable drum to wind and unwind the cable from the cable drum.

Additionally, the cable drum has a horizontal rotation axis, and the cable drum is disposed perpendicular to the bottom of the main body.

Additionally, the cable includes a bundle of optical fiber cores made by bundling a plurality of optical fibers.

In addition, it further includes a cable guide member for guiding the cable unwound from the cable drum.

In addition, the cable guide member includes a rail; A slide member capable of sliding on the rail; And it includes a front guide member that has an arc shape and is coupled to the end of the slide member.

Additionally, the rail is installed inside the main body, and the slide member is installed to be able to slide from inside the main body to the outside.

Additionally, the front guide member is inserted into the cable to form a guide groove that guides the movement of the cable, and is rotatably coupled to one end of the slide member.

Additionally, the cable guide member further includes a laser pointer coupled to an end of the front guide member.

Additionally, a pair of coupling members coupled to the front of the main body; And it further includes a handrail mounting member coupled to the front of each of the coupling members and including a support plate extending downward from the coupling member.

In addition, the handrail holding member further includes a support member that is movably coupled to each of the coupling members by an adjustment screw.

Additionally, the rotating member includes a first motor for rotating the cable drum.

Additionally, a pair of support wheels disposed above and below the cable unwound from the cable drum to support the cable; and a second motor for rotating one of the pair of support wheels.

Additionally, the radiation detector is a solid body; It is inserted into the cylinder and contains a P-terphenyl organic scintillator.

Additionally, the radiation detector further includes a tungsten rod disposed inside an end of the cylinder.

In addition, the cylinder includes a first cylinder made of stainless steel; and

It is coupled to an end of the first cylinder and includes a second cylinder made of aluminum.

According to the present invention, a spent nuclear fuel inspection device is provided that is easy to handle and operate, and improves inspection efficiency by improving the sensitivity of the inspection device.

Figure 1 is a perspective view showing a conventional radiation detection system mounted on a bridge;
Figure 2 is a diagram showing the radiation detection system of Figure 1,
Figure 3 is an overall perspective view of the heavy water reactor spent nuclear fuel inspection device according to the present invention;
Figure 4 is a diagram showing a state in which the cover in Figure 3 is removed;
Figure 5 is a view from a different angle with the cover removed from Figure 3;
Figure 6 is a side view with one cover removed from the spent nuclear fuel inspection device according to the present invention;
Figure 7 is a diagram showing the winding and unwinding process of the cable to which the radiation detector is connected in the present invention;
Figure 8 is a diagram showing a radiation detector in the present invention;
Figure 9 is a diagram showing the interior of the radiation detector in the present invention.
Figure 10 is a diagram showing the results of testing a conventional inspection device and an inspection device according to the present invention in an actual nuclear power plant.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques are not specifically described to avoid ambiguous interpretation of the present invention. Like reference numerals refer to like elements throughout the specification.

In the drawing, the thickness is enlarged to clearly express various layers and regions. Throughout the specification, similar parts are given the same reference numerals. When a part of a layer, membrane, region, plate, etc. is said to be "on" another part, this includes not only being "directly above" the other part, but also cases where there is another part in between. Conversely, when a part is said to be “right on top” of another part, it means that there is no other part in between. Additionally, when a part of a layer, membrane, region, plate, etc. is said to be “below” another part, this includes not only cases where it is “directly below” another part, but also cases where there is another part in between. Conversely, when a part is said to be "right below" another part, it means that there is no other part in between.

Spatially relative terms such as “below”, “beneath”, “lower”, “above”, “upper”, etc. are used as a single term as shown in the drawing. It can be used to easily describe the correlation between elements or components and other elements or components. Spatially relative terms should be understood as terms that include different directions of the element during use or operation in addition to the direction shown in the drawings. For example, if an element shown in the drawings is turned over, an element described as “below” or “beneath” another element may be placed “above” the other element. Accordingly, the illustrative term “down” may include both downward and upward directions. Elements can also be oriented in other directions, so spatially relative terms can be interpreted according to orientation.

In this specification, when a part is connected to another part, this includes not only the case where it is directly connected, but also the case where it is connected with another element in between. Additionally, when it is said that a part includes a certain component, this does not mean that other components are excluded, but that it may further include other components, unless specifically stated to the contrary.

In this specification, terms such as first, second, and third may be used to describe various components, but these components are not limited by the terms. The above terms are used for the purpose of distinguishing one component from other components. For example, without departing from the scope of the present invention, the first component may be named a second or third component, etc., and similarly, the second or third component may also be named alternately.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless clearly specifically defined.

Hereinafter, a spent nuclear fuel inspection device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

Figure 3 is an overall perspective view of the spent nuclear fuel inspection device according to the present invention, Figure 4 is a diagram showing a state with the cover removed from Figure 3, and Figure 5 is a view from a different angle with the cover removed from Figure 3. It is a drawing, Figure 6 is a side view with one cover removed from the heavy water reactor spent nuclear fuel inspection device according to the present invention, Figure 7 is a diagram showing the winding and unwinding process of the cable to which the radiation detector is connected in the present invention, and Figure 8 is This is a diagram showing the radiation detector in the present invention, and Figure 9 is a diagram showing the inside of the radiation detector in the present invention.

A spent nuclear fuel inspection device 1000 according to an embodiment of the present invention includes a main body 1100; cable (1200); A radiation detector 1300 installed at the end of the cable 1200; cable drum (1400); and a rotating member for rotating the cable drum 1400.

As shown in FIGS. 3 to 6, the main body 1100 has a substantially rectangular parallelepiped shape, and component parts such as a cable drum 1400 are built into the main body 1100, and a cover is attached to each side.

The cable drum 1400 is installed inside the main body, and the cable 1200 is wound around the outer peripheral surface. The cable drum 1400 is rotated by a rotating member, so that the cable 1200 is wound on the cable drum 1400 or the cable drum ( The cable 1200 is unwound from 1400).

In the present invention, the cable drum 1400 is arranged in a cylindrical shape, standing vertically on the horizontal bottom of the main body 1100, and is disposed within the main body 1100 to have a horizontal rotation axis 1410.

The rotating member is for rotating the cable drum 1400 and includes a first motor 1510 (see FIG. 5). By rotating the first motor 1510, the cable drum 1400 rotates clockwise or counterclockwise. It rotates clockwise, and as the cable drum 1400 rotates, the cable 1200 is released or wound around the cable drum 1400.

As shown in Figure 4, a drum control button 1102 is provided on the upper surface of the main body 1100 to manipulate the rotation of the cable drum 1400. In this embodiment, two drum control buttons 1102 are disposed on the upper surface of the main body 1100, one for winding the cable 1200 around the cable drum 1400 and the other for unwinding the cable 1200. By pressing one of these two buttons, the cable 1200 is wound or unwound from the cable drum 1400.

Additionally, an emergency stop button 1103 is provided on the upper surface of the main body 1100. If it is necessary to urgently stop while the cable 1200 is being wound or unwound from the cable drum 1400 by pressing the drum control button 1102, the rotation of the cable drum 1400 is stopped by pressing the emergency stop button 1103 and the cable (1400) is pressed. 1200) stops moving.

A cable guide member 1600 is provided to guide the cable 1200 that is wound or unwound from the cable drum 1400.

The cable guide member 1600 includes a rail 1610 as shown in Figure 4; A slide member 1620 that slides on the rail 1610; and a front guide member 1630 that has an arc shape and is coupled to the end of the slide member 1620.

In the cable guide member 1600, the rail 1610 is installed on the bottom of the main body from the lower side of the cable drum inside the main body and extends from the main body in the front and rear direction.

The slide member 1620 is slidably coupled to the rail 1610, and as shown in Figure 6, a guide groove 1621 is formed in the center along the longitudinal direction to guide the cable. The slide member 1620 may be introduced into the main body 1100 along the rail 1610 or may be completely pulled out of the main body 1100 as shown in FIG. 4 .

The front guide member 1630 is coupled to the front end of the slide member 1620 to guide the movement of the cable 1200. The rear end of the front guide member 1630 is rotatably coupled to the slide member 1620 and is shown in Figure 4. As shown, the shear has a downwardly curved arc shape.

In addition, the cable 1200 is inserted into the front guide member 1630, and a guide groove 1635 is formed along the longitudinal direction to guide the movement of the cable 1200, and a laser pointer 1640 is installed at the front end of the front guide member 1630. ) is placed.

The laser pointer 1640 is installed at the end of the front guide member 1630 to irradiate a laser. The laser is irradiated from the laser pointer 1640 to ensure that the radiation detector 1300 is accurately positioned on the nuclear fuel to be inspected.

To operate the laser pointer 1640, a laser pointer button 1101 is placed on the upper surface of the main body. By pressing this laser pointer button 1101, power is supplied to the laser pointer 1640.

As shown in FIG. 7, a pair of support wheels 1450 are provided between the cable drum 1400 and the front guide member 1630. A pair of support wheels 1450 are disposed above and below the cable 1200 between the cable drum 1400 and the front guide member 1630 and allow the cable 1200 unwound from the cable drum 1400 to move stably. .

Additionally, a second motor 1455 is connected to one support wheel 1450 and rotated by the second motor 1455. Accordingly, the support wheel 1450 is rotated by the second motor 1455 to guide the movement of the cable 1200 and adjust the tension of the cable 1200 so that the cable 1200 moves stably without being twisted. The rotational force of the second motor is transmitted to the support wheel 1450 through a plurality of gears.

A handrail mounting member 1150 is disposed in front of the main body 1100 as shown in FIGS. 3 and 4.

The handrail mounting member 1150 is for mounting the inspection device main body 1100 of the present invention on a handrail (not shown) and includes a pair of coupling members 1151 coupled to the front of the main body 1100; and a support plate 1152 coupled to the front of each coupling member 1151 and extending downward from the coupling member 1151. In addition, each coupling member 1151 is further provided with a support member 1154 that can be moved up and down (see Figure 6).

A pair of coupling members 1151 are respectively coupled to the front cover of the main body 1100 while being spaced apart at a certain distance from the side, and a support plate 1152 is coupled to the front of each coupling member 1151.

Therefore, the railing (not shown) of the storage where the nuclear fuel to be inspected is stored is inserted between the support plate 1152 and the front cover of the main body 1100, so that the main body 1100 is mounted on the railing, and the coupling member 1151 and the support member (1154) is supported on the upper part of the handrail.

In addition, the support member 1154 can be moved up and down by the adjustment screw 1153, and each support member 1154 is adjusted using the adjustment screw 1153 so that it is stably supported on the handrail.

The cable 1200 is used to transmit light generated by the radiation detector 1300, and in the present invention, it is made of an optical fiber cable.

The radiation detector 1300 is installed at the end of the cable 1200 to detect radiation emitted from nuclear fuel, and includes a cylinder 1310; and a scintillator 1330 that is inserted into the cylinder 1310 and detects radiation.

In the radiation detector 1300, the cylinder 1310 includes a first cylinder 1311 connected to a cable and a second cylinder 1312 connected to the first cylinder 1311. In this embodiment, the first cylinder 1311 is made of stainless steel (SUS), and the second cylinder 1312, inside which the scintillator 1330 is disposed, is made of aluminum to improve radiation sensitivity.

A tungsten rod 1320 is disposed at the end of the cylinder 1310, that is, inside the end of the second cylinder 1312. In the present invention, a tungsten rod 1320, which serves as a weight, is inserted into the end of the second cylinder 1312 to allow the radiation detector 1300 to smoothly move to the nuclear fuel in the reservoir.

Additionally, a spring 1340 for cushioning the scintillator 1330 is disposed between the scintillator 1330 and the tungsten rod 1320 within the second cylinder 1312.

The scintillator 1330 is for converting radiation into light, and in the present invention, a P-terphenyl organic scintillator made of P-terphenyl is used.

In this way, in the present invention, the P-terphenyl organic scintillator (producing about 27,000 lights when depositing 1 Mev gamma ray) is applied, thereby improving signal sensitivity compared to the existing Li-glass scintillator (producing about 4,000 lights when depositing 1 Mev gamma ray). improves.

In addition, in the present invention, the optical cable 1200 is made of a bundle of optical fibers by bundling a plurality of optical fibers. In this embodiment, 64 fine optical fibers with a diameter of about 200 μm were bundled to produce a bundled optical fiber with a core diameter of 1.8 mm.

Since the existing cable is an optical cable composed of two optical fibers with a single core diameter of 1.0 mm rather than a bundle of optical fibers, the overall optical cable diameter is large (the outermost diameter is 1.0 mm), and the flexibility is not good, and the radiation detector does not move smoothly between nuclear fuels. It caused the problem of not being able to do it.

In the present invention, since the optical fiber core diameter of the optical cable 1200 is large, light transmission efficiency is high and a radiation scintillator large in proportion to the diameter can be used, thereby increasing the amount of light generated by radiation. In the present invention, the optical cable 1200, unlike existing cables (existing optical cables use two optical fibers), uses only one optical fiber and has an outermost diameter of 6 mm, which is smaller than that of existing optical cables.

The optical fiber of the cable 1200 transmits the light generated by the scintillator 1330 to a light multiplier tube (PMT) attached to the signal processing device 1700.

Figure 10 is a diagram showing the results of testing the conventional inspection device shown in Figures 1 and 2 and the inspection device according to the present invention in an actual nuclear power plant.

As shown in Figure 10, the inspection device according to the present invention (bold solid line in Figure 10 New

The sensitivity of the OFPS (OFPS) was found to be at least 15 times better than that of the conventional inspection device (thin solid line Existing OFPS in Figure 10) (the size of the left and right signals is at least 15 times more). In addition, signals that could not be found in conventional inspection devices were measured with the device according to the present invention (the four points marked with circles are signals that could not be found in conventional devices).

In addition, the conventional device often became caught in surrounding nuclear fuel bundles during the inspection of spent nuclear fuel in the heavy water reactor, but the radiation detector of the present invention did not encounter such a situation, thereby reducing inspection time and effort.

Therefore, the inspection device according to the present invention can be manufactured with less than half the weight and volume of the conventional device, making it convenient to handle and operate. Unlike the conventional device, one person can operate the equipment alone, and the signal sensitivity to radiation is low. It is at least 15 times more powerful and can measure even minute radiation signals that cannot be measured with existing devices, which has the advantage of improving the convenience of using the device and saving inspection time and effort.

In addition, in the conventional device shown in Figures 1 and 2, the cable storage unit 101 in which the cable is stored is installed horizontally, the cable is stored in the cable storage unit, and the cable moves in the up and down direction, causing the cable to become tangled. , In the present invention, the cable 1200 is wound around the outer peripheral surface of the cable drum 1400, and the cable drum 1400 itself is rotated by the rotation of the first motor 1510, thereby solving the problem by winding or unwinding the cable 1200.

In addition, the radiation detector according to the present invention is thinner and more flexible than existing radiation detectors, and by increasing the weight of the lowest part of the radiation detector, the problem of the radiation detector being caught between bundles of surrounding spent nuclear fuel during inspection of spent nuclear fuel is also solved.

Above, the present invention has been described with reference to preferred embodiments, but the present invention is not limited thereto, and various modifications may be made by those skilled in the art without departing from the gist of the present invention as set forth in the claims below. There will be.

1000: Spent nuclear fuel inspection device 1100: Main body
1200: Cable 1300: Radiation detector
1400: cable drum 1600: cable guide member

Claims (17)

main body;
cable;
a radiation detector installed at the end of the cable to detect radiation emitted from spent nuclear fuel;
a cable drum installed inside the main body and having the cable wound around its outer circumferential surface; and
It includes a rotating member provided in the main body to rotate the cable drum to wind and unwind the cable from the cable drum,
The radiation detector is
whole body;
A scintillator inserted into the cylinder; and
A spent nuclear fuel inspection device comprising a tungsten rod disposed inside an end of the cylinder. According to paragraph 1,
The cable drum has a horizontal rotation axis,
The cable drum is a spent nuclear fuel inspection device arranged perpendicularly to the bottom of the main body. According to paragraph 1,
The cable is a spent nuclear fuel inspection device that is an optical cable including a bundle of optical fiber cores made by bundling a plurality of optical fibers. According to paragraph 1,
A spent nuclear fuel inspection device further comprising a cable guide member for guiding the cable unwound from the cable drum. According to paragraph 4,
The cable guide member is
rail;
A slide member capable of sliding on the rail; and
A spent nuclear fuel inspection device including a front guide member that has an arc shape and is coupled to an end of the slide member. According to clause 5,
The rail is installed inside the main body,
A spent nuclear fuel inspection device in which the slide member is installed to slide from inside the main body to the outside. According to clause 5,
The front guide member is a spent nuclear fuel inspection device in which the cable is inserted to form a guide groove that guides the movement of the cable, and is rotatably coupled to one end of the slide member. In clause 7,
The cable guide member is a spent nuclear fuel inspection device further comprising a laser pointer coupled to an end of the front guide member. According to paragraph 1,
A pair of coupling members coupled to the front of the main body; and
A spent nuclear fuel inspection device further comprising a handrail mounting member coupled to a front of each of the coupling members and including a support plate extending downward from the coupling member. According to clause 9,
The railing holding member is a spent nuclear fuel inspection device further comprising a support member that is movably coupled to each of the coupling members by an adjustment screw. According to paragraph 1,
The rotating member is a spent nuclear fuel inspection device including a first motor for rotating the cable drum. According to clause 11,
a pair of support wheels disposed above and below the cable unwound from the cable drum to support the cable; and
A spent nuclear fuel inspection device further comprising a second motor for rotating one of the pair of support wheels. delete According to paragraph 1,
The scintillator is a spent nuclear fuel inspection device that is a P-terphenyl scintillator. delete According to clause 14,
The above body is
A first cylinder made of stainless steel; and
A spent nuclear fuel inspection device comprising a second cylinder coupled to an end of the first cylinder and made of aluminum. According to paragraph 1,
The radiation detector is a spent nuclear fuel inspection device further comprising a spring disposed between the scintillator and the tungsten rod inside the cylinder.

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