JPH11125677A - Radioactivity measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioactivity measuring device capable of specifying the emitting location of radiation for the whole outer surface and measuring the radiation does at the location without causing failure or shifting of each optical fiber wound around a container when moving and the like. SOLUTION: On the upper and lower surfaces and each side surface of a container of radioactive material or radioactive waste, first to fourth belt shape protection grooves 8(1) to 8(4) are formed and in the protection grooves 8(1) to 8(4), first to fourth optical fibers 2(1) to 2(4) for radiation measurement are arranged and both ends of the first to fourth optical fibers 2(1) to 2(4) are connected to a radiation measuring device. With the first to fourth optical fibers and the radiation measuring device, the emission location of radiation outside the container 1 is specified and radiation dose equivalent of the location in measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring radioactivity, and more particularly, to the outside of a large storage container for storing radioactive materials or radioactive waste, which is used in facilities handling radioactive materials such as nuclear power plants. The present invention relates to a radioactivity measuring device for measuring a radiation dose equivalent rate of a radioactivity.

[0002]

2. Description of the Related Art Conventionally, a radioactivity measuring apparatus for safely measuring the radiation dose equivalent rate outside a storage container when a radioactive substance or radioactive waste is stored in the storage container is disclosed in JP-A-9-80156. A radiation measuring device disclosed in the official gazette, a container surface dose measuring device disclosed in Japanese Utility Model Registration No. 3031656, and the like are known.

[0003] Here, a radiation measuring apparatus disclosed in Japanese Patent Application Laid-Open No. 9-80156 puts a storage container containing a radioactive substance or radioactive waste in a measurement container and inserts a long scintillation fiber around the outer periphery of the measurement container. It is wound spirally, and both ends of the scintillation fiber are connected to a time difference measurement circuit. When radiation enters the scintillation fiber during radiation measurement, light is generated in the scintillation fiber at the incident part and propagates through the scintillation fiber, so the time difference measurement circuit measures the arrival time difference of the light transmitted through the scintillation fiber. Then, it is possible to specify a radiation incident point and measure a radiation dose at the point.

[0004] A container surface dose measuring device disclosed in Japanese Utility Model Registration No. 3031656 is a cylindrical detection unit in which a plastic scintillation fiber is spirally wound around a storage container storing a radioactive substance or radioactive waste. Are arranged, and both ends of the plastic scintillation fiber are connected to a time difference measurement circuit. The operation at the time of radiation measurement is almost the same as that of the radiation measurement device disclosed in JP-A-9-80156. When radiation enters the scintillation fiber of the detection unit, light is generated in the scintillation fiber of the incident portion. Since the light propagates through the scintillation fiber, if the time difference measurement circuit measures the arrival time difference of the light transmitted through the scintillation fiber, it is possible to specify the radiation incident point and measure the radiation dose at the point.

[0005]

The above-mentioned known radiation measuring device and container surface dose measuring device measure a radiation emitting point by using a scintillation fiber wound around a measuring container or a storage container. Therefore, even if the measurement container or the storage container is enlarged, or even if the measurement container or the storage container is lifted by a crane, it is possible to keep the measurer in a relatively safe state. It is possible to specify the location of radiation emission in the measurement container or the storage container and measure the radiation dose at that location, but it seems that the measurement container or the storage container has become considerably large and its weight has increased. In such a case, the scintillation fiber wrapped around the floor may be If and in contact with any other object,
Depending on the weight of the measuring container or the storage container, the scintillation fiber wound on the outside may be damaged, or the winding position may be shifted even if it is not damaged. And the radiation dose at that location can no longer be measured,
Even if they are formed, there is a problem that the specification of the radiation emission location and the measurement result of the radiation dose at the location become inaccurate.

In the known radiation measuring device and the container surface dose measuring device, the scintillation fiber is wound only on the outer side surface of the measuring container or the storage container. There is also a problem that it is not possible to specify a radiation emission location on the upper and lower surfaces and measure a radiation dose at that location.

The present invention has been made to solve these problems, and an object of the present invention is to prevent radiation of the radiation wound on the entire outer surface without causing breakage or displacement of the fiber wound on the outer side when the storage container is moved. It is an object of the present invention to provide a radioactivity measuring device capable of specifying an emission point and measuring a radiation dose at the point.

[0008]

In order to achieve the above object, a radioactivity measuring apparatus according to the present invention has a band-shaped protective groove formed on the upper, lower, and side surfaces of a container for storing radioactive materials or radioactive waste. , A radiation measurement optical fiber is placed in the strip-shaped protection groove, a radiation measurement device is connected to both ends of the radiation measurement optical fiber, the radiation measurement device specifies the radiation emission location outside the storage container, and the radiation A means for measuring the dose equivalent rate is provided.

According to the above means, when the optical fiber for radiation measurement is wound around the outside of the storage container, the storage container is moved by being inserted into the band-shaped protection grooves provided on the upper, lower, and side surfaces of the outside of the storage container. When, for example, the outside of the storage container comes into contact with the floor surface or other objects, the weight of the storage container does not damage the radiation measuring optical fiber or shift the winding position, and
Since the radiation measuring optical fiber is wrapped around the entire outer surface of the storage container, it is possible to specify a radiation emission point on the entire outer surface of the storage container and measure the radiation dose equivalent rate at the position.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention, a radioactivity measuring device has a band-shaped protection groove formed on the upper, lower, and side surfaces of a container for storing a radioactive substance or radioactive waste. An optical fiber for radiation measurement is placed inside, a radiation measurement device is connected to both ends of the optical fiber for radiation measurement, the radiation measurement device specifies the radiation emission location outside the storage container, and measures the radiation dose equivalent rate at that location Is what you do.

In one embodiment of the present invention, in the radioactivity measuring device, at least one of the band-shaped protection grooves is formed in the opening / closing portion of the storage container.

Further, in another embodiment of the present invention, the radioactivity measuring apparatus is one in which a plurality of radiation measuring optical fibers are disposed in a flat state in a strip-shaped protection groove.

According to the embodiments of the present invention, a band-shaped protection groove is formed on the upper, lower, and side surfaces of the outer side of the storage container for storing radioactive materials and the like, and the radiation measuring optical fiber is provided in the band-shaped protection groove. Is arranged so that the optical fiber for radiation measurement is wound around the outside of the storage container, so that when the storage container is lifted and moved, the outside of the storage container, particularly, the optical fiber for radiation measurement is wound. Even if the part comes into contact with the floor or other objects, the weight of the storage container does not damage the radiation measuring optical fiber, and the winding position of the radiation measuring optical fiber does not deviate from the predetermined measurement position, and It is not possible to specify the release location or measure the radiation dose equivalent rate at that location, or to specify the release location and measure the radiation dose equivalent rate. As also eliminates that the result or an incorrect.

According to these embodiments of the present invention, since the radiation measuring optical fiber is wound around all the outer surfaces of the storage container, radiation can be emitted to the entire outer surface of the storage container. It is possible to specify a location and measure the radiation dose equivalent rate of the location.

In this case, according to one embodiment of the present invention, at least one band-shaped protection groove is formed in the opening / closing portion of the storage container which is considered to emit the highest amount of radiation. Since the radiation measuring optical fiber is arranged in the strip-shaped protection groove, if the radiation dose equivalent rate from the storage container is measured using the radiation measuring optical fiber, the maximum radiation dose equivalent rate released from the storage container can be determined. Measurement can be performed, and the limit storage amount of a radioactive substance or the like that can be stored in the storage container can be appropriately grasped using the measurement result.

According to another embodiment of the present invention, when a plurality of radiation measuring optical fibers are arranged in parallel to increase the radiation dose equivalent rate measurement efficiency, a plurality of radiation measuring optical fibers are required. Is flat, and the cross-sectional shape of the band-shaped protective groove is matched to the flat state.Therefore, without impairing the mechanical strength and radiation shielding rate of the storage container, a highly efficient radiation dose equivalent rate can be obtained. A measurement can be made.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of one embodiment of the radioactivity measuring apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a storage container for radioactive waste, 2 (1), 2 (2),..., 2 (4), 4 which are separately wound around the outside of the storage container 1 as described later. The first to fourth plastic scintillation optical fibers (hereinafter referred to as first to fourth optical fibers), 3 (1), 3 (2),..., 3 (4) are four first to fourth plastic scintillation optical fibers. 4, a photoelectric converter, 4 is a time-peak value converter,
5 is a radiation measuring instrument, 6 is a display, 7 (1), 7 (2),
.., 7 (4) are the corresponding first to fourth optical fibers 2 (1), 2 (2),..., 2 (4) and the first to fourth photoelectric converters 3 (1), 3 (3). (2), ..., 3 (4)
And a first to a fourth quartz optical fiber pair respectively connecting the first to fourth optical fibers.

FIGS. 2A and 2B are diagrams showing a first example of the structure of the radioactive waste storage container 1 of the radioactivity measuring apparatus shown in FIG. () Is a perspective view, and (b) is a sectional view of a central portion thereof.

2 (a) and 2 (b), 1 (1) is the upper container of the storage container 1, 1 (2) is the lower container of the storage container 1, and 1 (3) is the radioactive disposal of the storage container 1. Object storage, 1
(4) is the opening / closing part of the storage container 1, and 8 (1) is the upper container 1.
(1) A first band-shaped protection groove formed on the outer upper surface and the outer rear side surface, and 8 (2) is a second band-shaped protection groove formed on the outer lower surface and the outer rear side surface of the lower container 1 (2). Groove, 8
(3) is a third band-shaped protection groove formed on the outer front side surface, both side surfaces, and the outer rear side surface of the upper container 1 (1), and 8 (4) is the outside of the lower container 1 (2). Fourth belt-shaped protection grooves formed on the front side surface, both side surface surfaces, and the outer rear side surface, respectively, and the same components as those shown in FIG. 1 are denoted by the same reference numerals.

The storage container 1 is composed of an upper container 1 (1) and a lower container 1 (2) joined by an opening / closing section 1 (4).
The radioactive waste storage part 1 (3) is formed in the center. Outside the upper container 1 (1) of the storage container 1, a first band-like protection groove 8 (1) is formed on the upper surface and the rear side surface, and a third band-like protection groove is formed on the front side surface, both side surfaces, and the rear side surface. Protection groove 8 (3) is formed. Outside the lower container 1 (2) of the storage container 1, a second band-like protection groove 8 (2) is formed on the lower surface and the rear side surface, and the fourth band-shaped protection groove 8 (2) is formed on the front side surface, both side surfaces, and the rear side surface. A band-shaped protection groove 8 (4) is formed.

In this case, the first band-shaped protection groove 8 (1)
The upper surface has a substantially U-shape, and the shape of the rear side surface is a parallel-line shape extending in the vertical direction, and both ends of the substantially U-shaped groove have respective parallel linear grooves. The first band-shaped protection groove 8 has a shape connected to one end.
A first optical fiber 2 (1) is arranged in (1),
A first optical fiber 2 (1) is wound around the storage container 1, and a first quartz optical fiber pair 7 (1) is connected to both ends of the first optical fiber 2 (1). The second band-shaped protection groove 8 (2) has a substantially U-shaped lower surface and a parallel-line shape with a rear side surface extending in a vertical direction, and has a substantially U-shaped groove. Both ends are connected to one end of each of the parallel linear grooves, and the second optical fiber 2 (2) is disposed in the second strip-shaped protection groove 8 (2), and the storage container 1 is formed. Is wound around the second optical fiber 2 (2), and a second quartz optical fiber pair 7 (2) is connected to both ends of the second optical fiber 2 (2). The third band-shaped protection groove 8 (3) is a straight type in which the shape of the front side surface and the side surfaces of the side portions extend straight in the horizontal direction, and a pair of portions in which the shape of the rear side surface slightly extends in the horizontal direction. Both ends of the straight groove on the front side face and one end of the straight groove on both side faces are continuous, and each other end of the straight groove on the both side faces is straight. The third optical fiber 2 (3) is disposed in the third band-shaped protective groove 8 (3), and is connected to one end of the linear groove. 2 (3) is wound and the third
A third quartz optical fiber pair 7 (3) is connected to both ends of the optical fiber 2 (3). Fourth belt-shaped protection groove 8
(4) is a pair of partially linear type in which the shape of the front side surface and the side surface portions extend straight in the horizontal direction, and the shape of the rear side surface slightly extends in the horizontal direction; Both ends of the straight groove on the front side and one end of the straight groove on both sides are connected, and the other end of the straight groove on both sides is connected to one end of the partially straight groove. The fourth optical fiber 2 (4) is arranged in the fourth strip-shaped protection groove 8 (4), and the fourth optical fiber 2 (4) is wound around the storage container 1, Fourth quartz optical fiber pair 7 is provided at both ends of fourth optical fiber 2 (4).
(4) is connected.

Further, the first quartz optical fiber pair 7 (1)
Is connected to the input of the first photoelectric conversion unit 3 (1), and the other end of the second quartz optical fiber pair 7 (2) is connected to the second photoelectric conversion unit 3 (1).
At the input of (2), the other end of the third quartz optical fiber pair 7 (3) is connected to the input of the third photoelectric conversion unit 3 (3), and the other end of the fourth quartz optical fiber pair 7 (4) is 4 photoelectric conversion unit 3
The outputs of the first to fourth photoelectric conversion units 3 (1) to 3 (4) are connected to the inputs of the time-to-peak value converter 4, respectively. The output of the time-to-peak value converter 4 is connected to the input of the radiation measuring instrument 5, and the output of the radiation measuring instrument 5 is connected to the output of the display 6.

An apparatus for measuring radioactivity according to the above configuration is schematically described as follows.
It works as follows.

For the storage container 1 in which the radioactive waste is stored in the radioactive waste storage unit 1 (3), the first to fourth strip-shaped protection grooves 8 (1) to 8 formed outside the storage container 1.
(4) First to fourth optical fibers 2
(1) to 2 (4) are arranged, and the first to fourth optical fibers 2 (1) to 2 (4) are respectively connected via the first to fourth quartz optical fiber pairs 7 (1) to 7 (4). To connect to the first to fourth photoelectric conversion units 3 (1) to 3 (4) to start measurement.

Now, the first to fourth belt-shaped protection grooves 8 (1) to 8 (4) wound around the storage container 1 are inserted into the storage container 1 respectively.
When the radiation emitted from the device enters, the first to fourth band-shaped protection grooves 8 (1) to 8 (8) at the portions where the radioactivity is incident
Light is generated in (4).

Here, for the sake of simplicity, if light is generated only in the first band-shaped protection groove 8 (1),
The generated light propagates in the first band-like protection groove 8 (1) in both directions from the generation position as a light pulse, reaches the respective ends, and then flows through the first quartz optical fiber pair 7 (1). The light propagates and is input to the first photoelectric conversion unit 3 (1), and the two light pulses are converted into two pulse signals. Next, the two pulse signals output from the first photoelectric conversion unit 3 (1) are supplied to the time-to-peak value converter 4, where they are converted into a time difference signal representing the arrival time difference between the two pulse signals. .
Next, the time difference signal output from the time-to-peak value converter 4 is supplied to the radiation measuring device 5, where the light enters the first band-shaped protection groove 8 (1) from the time difference signal, that is, is stored. The location where radiation is emitted from the container 1 is specified, the radiation dose equivalent rate of the specified location is measured, and the results are supplied to the display 6. The radiation emission location and the radiation dose equivalent rate at that location are displayed.

In this case, even if the radiation emitted from the storage container 1 is incident on two or three or more locations of the first optical fiber 2 (1), the same processing as in the above case is performed. It is possible to specify two or three or more respective radiation incident points and measure the radiation dose equivalent rate for each of the specific points. In addition to the case where the radiation emitted from the storage container 1 is incident on the first optical fiber 2 (1), any of the other second to fourth optical fibers 2 (2) to 2 (4) is used. In the case where the radiation is incident on one or more of the optical fibers 2 (1) to 2 (4), the same processing as in the above case is performed. It is possible to specify the radiation incident point and measure the radiation dose equivalent rate for each specific point.

The radiation measuring device 5 represents the relationship between the magnitude of the input time difference signal and the radiation emitting point of the storage container 1 for each of the first to fourth optical fibers 2 (1) to 2 (4). The information is stored in advance, and it is determined which of the first to fourth optical fibers 2 (1) to 2 (4) is the time difference signal supplied from which of the optical fibers 2 (1) to 2 (4). By discriminating and simultaneously determining the magnitude of the time difference signal, it is possible to specify the radiation emission location of the storage container 1 corresponding to the supplied time difference signal and measure the radiation dose equivalent rate of the specific location. It is.

As described above, according to the present embodiment using the storage container 1 of the first example, the first to fourth strip-shaped protection grooves 8 (1) to 8 (1) are formed on the upper, lower, and side surfaces of the storage container 1 outside. 8 (4), and first to fourth strip-shaped protection grooves 8 (1) to 8 (8).
(4) First to fourth optical fibers 2
Since (1) to (4) are arranged, when the container 1 is lifted and moved, the outside of the container 1, particularly, the first to fourth optical fibers 2 (1) to 2 (4) are used. Even if the wrapped portion comes into contact with the floor or another object, the weight of the storage container 1 may damage the first to fourth optical fibers 2 (1) to 2 (4), or the wrapped position of the first to fourth optical fibers may be changed from a predetermined position. It does not shift, so that it is not impossible to specify the radiation emission location, to measure the radiation dose equivalent rate at the specific location, or to be inaccurate.

FIG. 3 is a sectional view of a central portion showing a second example of the configuration of the radioactive waste storage container 1 of the radioactivity measuring apparatus shown in FIG.

In FIG. 3, the same components as those shown in FIGS. 2A and 2B are denoted by the same reference numerals.

The storage container 1 of the second example shown in FIG. 3 (hereinafter referred to as the second storage container) and FIGS. 2 (a) and 2 (b)
Is different from the storage container 1 of the first example (hereinafter referred to as a first storage container) in the configuration of the upper container 1 (1). Is not formed and the third optical fiber 2 (3) is not wound, whereas the first storage container has the third band-shaped protection groove 8 (3) on the outer side surface. (3) is formed, the third optical fiber 2 (3) is wound, and the configuration of the lower container 1 (2) is as follows.
The second storage container has a fourth band-shaped protection groove 8 (4) formed in a portion of the outer side surface close to the opening / closing portion 1 (4), and as a result, the fourth storage container 8 (4) is close to the opening / closing portion 1 (4). Optical fiber 2
Whereas (4) is arranged, the first storage container has a fourth strip-shaped protection groove 8 (4) formed in a portion of the outer side surface away from the opening / closing portion 1 (4), and as a result, Opening / closing part 1 (4)
There is no difference in configuration between the second storage container and the first storage container except for the point that the fourth optical fiber 2 (4) is arranged apart from the first storage container. For this reason, further detailed description of the configuration of the second storage container is omitted.

The operation of the embodiment of the radioactivity measuring apparatus using the second container 1 is based on the fact that there is no third optical fiber 2 (3).
The operation of the embodiment of the radioactivity measuring apparatus using the first storage container 1 is almost the same as that of the first embodiment, except that it is not possible to specify the radiation emitting point and to measure the radiation dose equivalent rate of the specific point. Therefore, further detailed description of the operation of the embodiment of the radioactivity measuring device using the second storage container 1 will be omitted.

The effect that can be expected in the embodiment of the radioactivity measuring device using the second storage container 1 can be obtained in addition to the effect that can be expected in the embodiment of the radioactivity measuring device using the first storage container 1. In the embodiment of the radioactivity measuring apparatus using the second storage container 1, the fourth optical fiber 2 (4) is arranged near the opening / closing section 1 (4) where the radiation emission amount is the largest in the storage container 1. Therefore, if the radiation dose equivalent rate from the second storage container 1 is measured by the fourth optical fiber 2 (4), the limit storage of radioactive materials and the like that can be stored in the second storage container 1 is based on the measurement result. There is also an effect that the amount can be properly grasped.

FIG. 4 is a sectional view of a central portion showing a third example of the configuration of the radioactive waste storage container 1 of the radioactivity measuring apparatus shown in FIG.

In FIG. 4, 2 (1) ', 2 (2)',
Reference numeral 2 (4) 'denotes first, second, and fourth optical fiber bundles, and the same components as those shown in FIG. 3 are denoted by the same reference numerals.

The storage container 1 of the third example shown in FIG. 4 (hereinafter referred to as a third storage container) and the second storage container 1 shown in FIG.
The difference from the configuration of the storage container 1 is that, with respect to the configuration of the upper container 1 (1), the third storage container 1 is wide on the outer upper surface (in this example, the width is such that three optical fibers can be arranged side by side). Is formed, and a flat first optical fiber bundle 2 (1) ′ in which three optical fibers are arranged side by side in the belt-shaped protective groove 8 (1).
Whereas the second storage container 1 has a normal width on the outer upper surface (width enough to arrange one optical fiber).
Is formed, and one first optical fiber 2 (1) is formed in the band-shaped protection groove 8 (1).
And the configuration of the lower container 1 (2), the third storage container 1 has a wide fourth band-shaped protection groove in a portion of the outer side surface close to the opening / closing portion 1 (4). 8 (4) is formed, and a flat fourth optical fiber bundle 2 (4) ′ constituted by arranging three optical fibers side by side is arranged in the strip-shaped protection groove 8 (4). Second storage container 1
A fourth band-shaped protection groove 8 (4) having a normal width is formed in a portion of the outer side surface close to the opening / closing portion 1 (4), and one fourth protection groove 8 (4) is formed in the band-shaped protection groove 8 (4). Optical fiber 2 (4)
There is no difference in configuration between the third storage container 1 and the second storage container 1 in addition to the arrangement of For this reason, the detailed description of the configuration of the third storage container 1 will be omitted.

The operation of the embodiment of the radioactivity measuring device using the third container 1 is essentially the same as the operation of the embodiment of the radioactivity measuring device using the second container 1. So
The operation of the embodiment of the radioactivity measuring device using the third container 1 will not be described in further detail.

The effect that can be expected in the embodiment of the radioactivity measuring device using the third storage container 1 can be obtained in addition to the effect that can be expected in the embodiment of the radioactivity measuring device using the second storage container 1. In the embodiment of the radioactivity measuring device using the third storage container 1, one first, second, and fourth optical fiber 2 (1), 2 (2), 2 (4) are respectively provided.
, Flat first, second, and fourth optical fiber bundles 2 (1) ′ each having three optical fibers arranged side by side,
Since 2 (2) ′ and 2 (4) ′ are used, without impairing the mechanical strength and radiation shielding rate of the third storage container 1,
The radiation dose equivalent rate can be measured with high efficiency.

In this case, in the embodiment of the radioactivity measuring apparatus using the third storage container 1, the first, second, and fourth optical fiber bundles 2 (1) ', 2 (2)', 2 (4) 'Is an example in which three optical fibers are arranged side by side, but in the present embodiment, the number of optical fibers arranged side by side is not limited to three, and is not limited to two.
It may be a book or four.

In each of the above embodiments of the radioactivity measuring device, the first radioactivity measuring device formed on the outer upper surface of the upper container 1 (1) is not limited to the above.
, The formation position and the number of the third band-shaped protection grooves 8 (3) formed on the outer side surface, that is, the first wound around the upper container 1 (1). The winding position and the number of windings of the third optical fiber 2 (1), 2 (3) or the first optical fiber bundle 2 (1) ′ are limited to the examples shown in FIGS. 2 (b), 3 and 4. Instead, it can be appropriately changed according to the place where the emission of radiation is to be measured.

Similarly, in each of the above embodiments of the radioactivity measuring device, the second band-shaped protection groove 8 (2) formed on the outer upper surface of the lower container 1 (2) is formed on the outer side surface. 4th
Forming position and number of the band-shaped protective grooves 8 (4),
That is, the second and fourth optical fibers 2 (2) and 2 (4) wound around the lower container 1 (2) or the second and fourth optical fiber bundles 2 (2) 'and 2 (4)' The winding position and the number of windings are not limited to the examples shown in FIGS. 2B, 3, and 4, and can be appropriately changed according to a position where radiation emission is to be measured.

Furthermore, in the above-described embodiments of the radioactivity measuring apparatus, an example in which the radioactive substance contained in the storage container 1 is radioactive waste has been described. The substance stored in the inside is not limited to radioactive waste, but may be radioactive substance itself.

Incidentally, in the embodiment of the radioactivity measuring apparatus using the first to third storage containers 1, the first to fourth optical fibers 2 (1) to 2 (4) wound around each storage container 1 are: The maximum length at which radiation can be measured is about 10 m. For this reason, the first to fourth optical fibers 2 (1) to 2 (2) wound around the storage container 1
In (4), the first to fourth optical fibers 2 (1) to 2 (2) are selected such that the length of the wound portion is within 10 m.
First to fourth quartz fiber pairs 7 (1) to 7 (4) are connected to both ends of (4), respectively, and the first to fourth quartz fiber pairs 7 (1) to 7 (4) are connected to the first. The radiation dose measuring device in the first to third storage containers 1 is extended to the radioactivity measuring device at a position remote from the first to third storage containers 1 to measure the radiation dose equivalent rate at the remote position. In this case, the first to fourth quartz fiber pairs 7 (1) to 7 (4)
Can transmit light up to a length of about 2000 m, so that the location of the first to third storage containers 1 and the location of the radioactivity measuring device can be considerably separated.

Next, FIG. 5 is a schematic configuration diagram showing an example of a configuration procedure for storing radioactive waste in a storage container while measuring radioactivity in a reactor arrangement building.

In FIG. 5, reference numeral 9 denotes a radioactivity measuring device comprising first to fourth photoelectric converters 3 (1) to 3 (4), a time-to-peak value converter 4, a radiation measuring device 5, and a display 6. , 10
Is a pressure vessel, 11 is a shroud (before moving), 12 is a reactor well, 13 is water, 14 is a shroud (after moving), 1
Numeral 5 denotes a dryer separator pool, numeral 16 denotes an operation floor of a reactor building such as a nuclear power plant, and other components which are the same as those shown in FIG.

As shown in FIG. 5, the reactor building operation floor 16 is provided with a reactor well 12 in which the pressure vessel 10 is disposed on the bottom surface and a dryer separator pool 15 beside the reactor well 12. The well 12 and the dryer separator pool 15 are filled with water 13. The shroud 11 is housed inside the pressure vessel 10, and the radioactive waste storage container 1 is arranged in the water of the dryer separator pool 15. On the operation floor 16 of the reactor building, which is slightly away from the dryer separator pool 15, a radioactivity measuring device 9 is arranged, and a plurality of optical fibers (not shown) wound around the outside of the storage container 1 are made of a plurality of quartz optical fibers. It is connected to the radioactivity measuring device 9 via a pair 7 (only one pair is shown in the figure).

In the above configuration, the procedure for storing the shroud 11 arranged in the pressure vessel 10 in the storage vessel 1 is as follows. First, a part of the shroud 11 is cut in water and the cut shroud 14 is removed. The water is transported into the dryer separator pool 15 while passing through the water using a crane. The shroud 14 in the dryer separator pool 15 is similarly re-cut in water, and the re-cut pieces of the shroud 14 are sequentially removed from the storage container 1 from which the upper container (not shown) has been removed using a crane. It is stored in a waste storage unit (also not shown). In this case, the storage container 1 has a capacity of about 20 to shield the radiation emitted from the shroud 14 having a high radiation dose rate.
cm of iron and the weight of the storage container 1 is about 20
Tons. When storing the shroud 14 fragments in the radioactive waste storage section of the storage container 1, the shroud 14 fragments are not directly stored in the radioactive waste storage section, but are made of iron having a thickness of about 1 to 5 mm. After being stored in an internal storage container (not shown), the internal storage container is stored in the radioactive waste container.

When a certain amount of fragments of the shroud 14 are stored in the radioactive waste storage portion of the storage container 1, the upper container is combined with the lower container (not shown), and the opening / closing portion of the storage container 1 is closed. At this time, the radioactivity measuring device 9 is operated to measure the dose equivalent rate of radiation emitted from the outside of the storage container 1 using a plurality of optical fibers wound around the outside of the storage container 1. As a result of this measurement, when the dose equivalent rate showed a value close to the specified dose equivalent rate, the storage container 1 was lifted out of the water by a crane and taken out of the water, and the storage container 1 was determined using predetermined transport means. Transport to storage location. On the other hand, the upper container is detached, the fragments of the re-cut shroud 14 are sequentially stored, and when an appropriate amount of the re-cut shroud 14 fragments are stored, the upper container is combined with the lower container, The opening and closing part of the storage container 1 is closed. Thereafter, the radioactivity measuring device 9 is operated to measure the dose equivalent rate of the radiation emitted from the outside of the storage container 1, and as a result of this measurement, the dose equivalent rate becomes a value close to the prescribed dose equivalent rate. At this time, the storage container 1 is taken out of the water, the storage container 1 is transported to a predetermined storage location, and if the dose equivalent rate is still considerably lower than the prescribed dose equivalent rate, the operation is repeated. Then, the operation of storing the shredded fragments of the shroud 14 and thereafter measuring the dose equivalent rate of the radiation emitted from the outside of the storage container 1 is executed.

In the present embodiment, the radioactive waste stored in the storage container 1 has been described as an example in which the radioactive waste stored in the storage container 1 is a fragment of the shroud 14.
It is not limited to such a fragment of the shroud 14 but may emit other radioactive waste, for example, neutron irradiation from the reactor fuel during the operation of the reactor if it emits radiation exceeding a specified value. Alternatively, various devices having radioactivity may be used.

[0053]

As described above, according to the present invention, a band-shaped protection groove is formed on the upper, lower, and side surfaces of the outer side of a storage container for storing radioactive substances and the like, and a radiation measuring groove is formed in the band-shaped protection groove. Since the optical fiber is arranged and thereby the optical fiber is wound around the outside of the storage container, when the storage container is lifted and moved, etc., the outside of the storage container, particularly, the portion where the optical fiber is wound around the floor or the like. Even if it comes into contact with other objects, the weight of the storage container will not damage the optical fiber, or the winding position of the optical fiber will not deviate from the predetermined measurement position. Even if the rate cannot be measured or the location of the release and the radiation dose equivalent rate can be measured, the results will not be inaccurate. There is an effect that.

According to the present invention, the optical fiber is wound around the entire outer surface of the storage container.
This has the effect that it is possible to specify the radiation emission location and measure the radiation dose equivalent rate at that location over the entire outer surface of the storage container.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration as an embodiment of a radioactivity measuring apparatus according to the present invention.

FIG. 2 is a configuration diagram showing a first example of a configuration of a storage container for radioactive waste of the radioactivity measuring apparatus shown in FIG. 1;

FIG. 3 is a cross-sectional view of a central portion showing a second example of the configuration of the radioactive waste storage container of the radioactivity measuring apparatus shown in FIG. 1;

FIG. 4 is a cross-sectional view of a central part showing a third example of the configuration of the radioactive waste storage container of the radioactivity measuring apparatus shown in FIG. 1;

FIG. 5 is a schematic configuration diagram showing an example of a procedure for storing radioactive waste in a storage container while measuring radioactivity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage container 1 (1) Upper container 1 (2) Lower container 1 (3) Storage part 1 (4) Opening part 2 (1) 1st optical fiber 2 (1) '1st optical fiber bundle 2 (2) Second optical fiber 2 (2) ′ Second optical fiber bundle 2 (3) Third optical fiber 2 (4) Fourth optical fiber 2 (4) ′ Fourth optical fiber bundle 3 (1) First photoelectric converter 3 (2) 2nd photoelectric converter 3 (3) 3rd photoelectric converter 3 (4) 4th photoelectric converter 4 time-crest value converter 5 radiation measurement device 6 display 7 (1) 1st The first pair of quartz optical fibers 7 (2) The second pair of quartz optical fibers 7 (3) The third pair of quartz optical fibers 7 (4) The fourth pair of quartz optical fibers 8 (1) The first strip-shaped protection groove 8 (2) 2 band-shaped protection groove 8 (3) 3rd band-shaped protection groove 8 (4) 4th band-shaped protection groove Groove 9 radioactivity measurement apparatus 10 pressure vessel 11 the shroud (before movement) 12 reactor well 13 Water 14 shroud (after movement) 15 Dryer separator pool 16 reactor building operation floor

Continued on the front page (72) Inventor Haruo Nakagawa 4-1-1 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. Engineering Co., Ltd. (72) Inventor Katsumi Hayashi 3-2-2, Sachicho, Hitachi City, Ibaraki Pref. Hitachi New Clear Engineering Co., Ltd.

Claims (3)

[Claims] 1. A band-shaped protection groove is formed on the upper, lower, and side surfaces of an outer side of a container for storing radioactive material or radioactive waste,
A radiation measuring optical fiber is arranged in the strip-shaped protective groove, both ends of the radiation measuring optical fiber are connected to a radiation measuring device, and radiation is emitted from the outside of the storage container by the radiation measuring optical fiber and the radiation measuring device. A radioactivity measuring device for identifying a location and measuring a radiation dose equivalent rate at the location. 2. The radioactivity measuring apparatus according to claim 1, wherein at least one of the band-shaped protective grooves is formed in an opening / closing portion of the storage container. 3. The radioactivity measurement apparatus according to claim 1, wherein a plurality of the radiation measurement optical fibers are arranged in the band-shaped protection groove in a state of being arranged flat. apparatus.