KR100729035B1 - Remote controllable neutron coincidence counter for non destructive accounting for nuclear material - Google Patents

Abstract

The neutron measuring apparatus of the present invention, an outer case, a neutron detector installed in a state surrounded by a moderator in the outer case, can be exposed outside the outer case through the movement in the outer case, the cavity is installed to accommodate the sample container It is made of a basket, and an external signal analyzer connected through the detector and the conductive path, the conductive path connecting the detector and the external signal analyzer is provided with a simple connector of the one-touch connection method of the wire connected to the connector The removal exchange can be made freely.

In the present invention, a shielding body such as a lead plate for radiation shielding is usually installed in the outer case, and an amplifier may be provided in the detector itself or in the vicinity of the detector to transmit the sensed neutron signal to the data processing device. To access the basket, hatches may be installed to open a portion of the exterior to open the interior portion to facilitate internal operation during maintenance.

Description

Remote control neutron measuring device for non-destructive nuclear material measurement {Remote controllable neutron coincidence counter for non destructive accounting for nuclear material}

1 is a schematic partial cross-sectional perspective view according to an embodiment of the present invention;

2 is a schematic side cross-sectional view according to an embodiment of the present invention;

3 and 4 are front and plan cross-sectional views of the hatch open in another embodiment of the present invention;

5 and 6 are side cross-sectional views in a basket embedded in and out of the neutron measuring device outer case in another embodiment of the present invention;

7 is a schematic connection diagram mainly showing the connection of a preamplifier, a signal line and a power line in one embodiment of the present invention;

8 and 9 are a perspective view and an extract showing a form in which the connection box and the preamplifier are connected in the embodiment of the present invention.

The present invention relates to a neutron measuring apparatus and a method of operating the same, and more particularly to a real-time neutron measuring apparatus suitable for non-destructive measurement, inspection of nuclear material in a high-level radiation environment and its operating method.

Working with high-level radioactive materials and nuclear materials, such as reprocessing nuclear fuel used in light water reactors, creates a high radiation environment, such as high-level gamma rays from nuclear materials. However, work can also be undertaken in such environments for practical purposes, such as light reactor fuel reprocessing, and remotely controllable work devices to perform these operations, for example in hot cells, which are facilities for handling high-level radioactive materials. And measurement and inspection devices.

A well-type neutron measuring device for measuring high radioactive materials is disclosed in Korea Patent Application No. 10-1998-0009907 filed by the Korea Atomic Energy Research Institute and Korea Electric Power Corporation.

In this device, a sample transport container containing a high-level radioactive material sample is placed in an internal decontamination vessel at a location where a sample is placed, and a neutron reflector is positioned above and below the sample. Outside the decontamination vessel, a shield protection plate and a gamma ray shield are installed, and a detection tube having a cadmium plate attached to a part of the shield outside. The plurality of detection tubes are surrounded by neutron decelerators in connection with the preamplifier at the top. All of them are surrounded by a main body case and supported by a main body support. Outside the main body case, various connectors and status check lamps are installed.

In addition, the detection tube is made of a material capable of easily separating the neutron signal into which the internal gas mixture is added together with the gamma ray signal, and the preamplifier to which the detection tube is connected is made of electronic components made of radiation resistant material.

By the way, such a conventional apparatus is provided so that a sample installation part may detach | desorb a sample in a vertical direction like the name expression of well type. In this form, only the inlet portion from which the sample is detached can be seen from the outside, which makes it difficult for the operator to visually check the working situation. Therefore, the task of detaching the sample through the remote controller as a whole becomes difficult, and there is a problem that the risk of operation such as sample dropout also increases due to incorrect operation or inaccurate judgment.

In addition, since these neutron measuring devices are present with these materials in a space that handles high-level radioactive materials, drawing out or reloading these devices from this space is very difficult and cumbersome. Therefore, these devices require very high reliability and durability. However, these equipments may have various problems, in which case, it is necessary to operate the equipment in the same space to solve the problems. In order to make this work easier through the remote controller, the work must be more stable.

However, the conventional neutron measuring apparatus cannot see the detection tube, the preamplifier connected to the detection tube, the signal line or the power line, and the connection terminal state thereof, which may cause problems, and thus maintenance operation is performed on them. It was hard to lose.

In this respect, the conventional vertical neutron measuring device has a problem in that it is inconvenient to maintain the equipment in terms of securing the field of view, operating safety.

The present invention is to solve the problems of the prior art, the object of the non-destructive nuclear material measuring device for maintenance and maintenance work for the neutron measuring device, a neutron measuring device having a configuration that can be convenient and stable operation It is done.

According to the present invention, it is also easy for the operator to check the state of the conductors and their connection terminals, such as signal lines connecting the detector portion of the neutron measuring device and the external signal analyzer, and other power lines, if necessary, It is an object of the present invention to provide a neutron measuring device having a configuration that is easy to replace.

The neutron measuring apparatus of the present invention for achieving the above object,

An outer case, a neutron detector installed in a state surrounded by a moderator in the outer case, a basket that is exposed to the outside of the outer case through movement in the outer case, the cavity is installed to accommodate the sample container, the detector and the conductive path It is provided with an external signal analyzer connected through, the conductive path connecting the detector and the external signal analyzer is installed in the simple connector of the one-touch connection method that can be freely removed and exchanged of the wire connected to the connector It features.

In the present invention, a shielding body such as a lead plate for radiation shielding is usually installed in the outer case, and an amplifier may be provided in the detector itself or in the vicinity of the detector to transmit the sensed neutron signal to the data processing device. To access the basket, hatches may be installed to open a portion of the exterior to open the interior portion to facilitate internal operation during maintenance. On the other hand, in the part where the shield is exposed to the outside as it is, the shield itself may be considered as an exterior case.

In the present invention, the basket may be made to be exposed out of the outer case of the neutron measuring apparatus of the present invention through the horizontal movement. At this time, in order to facilitate the horizontal movement of the basket, a part of the basket may be provided with a roller that can be rolled in the direction in which the basket is drawn out from the outer case. In addition, the basket may be formed without the upper wall or the cover of the basket so as to facilitate the detachment of the sample or the like above the cavity in which the sample or the sample container is placed in the horizontally moving basket.

In the present invention, the moderator and the shield body may be made of a plurality of parts separated in a horizontal (length) direction, and may be easily separated and mounted in the apparatus. In this case, a total or partial replacement of these moderators and shields can easily be made.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a schematic partial cross-sectional perspective view according to an embodiment of the present invention, Figure 2 is a schematic side cross-sectional view according to an embodiment of the present invention.

3 and 4 are a front view and a cross-sectional view of the hatch open in another embodiment of the present invention.

5 and 6 show side cross-sectional views in a basket embedded in and out of the neutron measuring device outer case in another embodiment of the present invention.

FIG. 7 is a schematic connection diagram mainly showing the connection of the preamplifier, the signal line and the power line in one embodiment of the present invention.

8 and 9 are a perspective view and an extract showing a form in which the connection box and the preamplifier are connected in the embodiment of the present invention.

According to one embodiment of the invention, one end of the closed cylindrical case made of stainless steel outer case 130 is installed with the open portion facing the horizontal. That is, the outer case 130 is cylindrical vessel type is installed so that the cylindrical central axis is located in the horizontal plane. A pedestal (not shown) may be installed below the outer case to stably install the device.

The blocking body 30 is installed inside the outer case. In some cases, the outermost shield may be an outer case. The blocking body 30 is a first shield portion that is installed in a cylindrical shape adjacent to the outer case 130, a second shield portion, a first shield portion and a cylindrically installed on a more central side spaced apart from the first shield portion a certain distance; It consists of a 3rd shield part which continues at the one side of a 2nd shield part, ie, the open part side edge part of an outer case, and covers a substantial outer part in the central axis of an outer case opening part. The shield is usually formed of a lead plate that can shield gamma rays, but in some cases other lighter shielding metals and alloys that are lighter in weight may be used. The second shield part blocks the gamma rays entering the detector so that the detection tube can accurately detect the neutrons. The outer first shield portion and the third shield portion prevent the detection tube 10 from being affected mainly by the gamma ray entry by the external nuclear material, and preamplifier 40 at one end of the detection tube 10. (B) serves to mitigate the effects of electronic and electrical components on radiation.

The basket 90 is provided inside the cylinder which a 2nd shield part forms. The basket 90 is also formed in the form of a cylinder partitioned with stainless, etc., the cavity 50 in which the sample is loaded is located in the middle, and the neutron reflector may be installed before and after the cavity in the longitudinal direction. As the reflector, nickel on the exterior case opening side and graphite on the exterior case closed end side may be used. In the cavity 50, a sample ingot or a container containing the sample is conveniently loaded upward, and is formed without an upper cylinder wall or a cover so as to be withdrawn, that is, in an open state. In this embodiment, the basket 90 is configured to have a space in which the nickel reflector 70 is installed and a cavity 50 space, and the graphite reflector 60 has a cavity 50 space on the closed surface of the exterior case 130. It is installed to be continuous. The basket 90 may be easily gripped by a handle 91 or a protrusion or a ring formed on the outer case opening side to be remotely controlled by the robot arm.

The reflector may use graphite and nickel materials having good neutron deceleration and reflection efficiency so that neutrons emitted from the sample 200, which are not directed toward the detector, may be detected by approaching the detector more through reflection. The reflector may be installed using a stainless casing when installed in the basket 90 or on the closed surface of the exterior case 130.

A plurality of detectors are installed in the space between the first shield and the second shield while annularly surrounding the basket 90 and the second shield located on the central axis of the outer case 130. The remaining space between the first shield and the second shield is filled with the neutron moderator 20 except for a portion of the outer case opening side. Therefore, the detector is surrounded by the moderator 20. At this time, the moderator decelerates the high speed neutron emitted from the nuclear material sample and converts it into a low speed thermal neutron and enables the reaction with the detection material in the detector with a high probability. As the moderator 20, a material such as high density polyethylene made of a material having a high unit volume hydrogen density may be used. The moderator 20 may also be provided on the sample facing surface of the nickel reflector or the graphite reflector.

The neutron detection internal medium of the detector is made of a material that can be easily separated from the neutron signal, which is input together with the gamma ray signal, from the gamma ray signal. The preamplifier 40 connected to the detector is made of an electronic component made of radiation resistant material. The detector is usually composed of a detection tube 10 in which helium, having a mass number of 3, is embedded at about several atmospheres, and the detection tube 10 may be formed of a thin aluminum tube sealed at both sides. Detection media such as helium form charged particles under the action of neutrons, which are captured by a detector to generate a current signal, which is converted into a voltage signal and sent to an external signal analyzer. Here, the preamplifier 40 is provided in the detection tube 10 toward the outer case opening side. The components constituting the preamplifier 40 are usually radiation resistant components. The preamplifier 40 may perform a function such as signal conversion and signal amplification of the current signal obtained from the detection tube 10 and is usually connected to an external power supply and a plurality of signal lines.

Preamplifiers are usually made of radiation-resistant components, but these components are often difficult to withstand in high-level radioactive environments and may need replacement. In addition, the detection tube 10 may also need to be replaced, for example, because airtightness is not maintained. In this embodiment, one end of the detection tube 10 and the portion of the preamplifier 40 connected thereto are formed in the form of a plug and a holder, and a predetermined number of electrical connection terminals are formed in an appropriate position at a suitable position inside the holder. We will use this type of holder with a simple connector. This simple insertion structure, with no threads on the plug and holder contact surfaces, allows for removal between the detection tube and the preamplifier without significant force. Therefore, in this structure, the electrical connection and physical detachment between the detection tube and the preamplifier can be easily made using the robot arm of the remote controller.

A cadmium moderator 80 may be attached to a portion of the center portion of the detection tube 10 in the longitudinal direction (outer case center axis direction) and a portion of the center portion of the outer shield to improve uniformity of neutron detection in the longitudinal direction.

An aluminum connection box 100 is installed in an empty space of the outer case opening side among the spaces between the first shield and the second shield. The connection box 100 may serve to position the detection tube 10 and the preamplifier 40 together with the moderator 20. The cable consisting of the leads drawn out of the preamplifier is in the form of a plug of type 1 with the other end having a multi-stage electrode. On one side of the connection box 100, a first type simple connector is formed corresponding to the number of detection tubes. A connection terminal corresponding to each signal line (conductor) is formed in the first type simple connector to be stepped to fit the first type plug shape therein. Insulation is provided between the connection terminals to prevent crosstalk. In the first type simple connector, a cable made of a plurality of conductors corresponding to the number of signal lines or power lines is drawn out and connected to an LED box (120) mounted through the outer case of the neutron measuring device and installed outside thereof. In addition, a second type simple connector is formed in the LED box, and is connected to an external power source or an external signal analyzer terminal by a second type plug and cable connected thereto.

Eventually, the signal and power terminals of the preamplifier can be connected to power and signal analyzers other than the neutron measuring device through a few simple plug-in simple connectors and plugs and cables connected thereto. The LED box is provided with a plurality of LED elements 115 to be connected through the detection tube 10 and the signal line. Accordingly, the LED element 115 emits light to externally recognize the neutron detection of the detector. The simple connector 110 of the LED box 120 or the connection box 100 becomes an intermediate connection point between an external power source and a signal line, and is disconnected or connected with a plug through a remote controller as necessary.

In another embodiment of Figs. 3 and 4, the third shield portion 31 of the embodiment of Figs. 1 and 2 is formed in a hatch type, which can be opened and closed. Therefore, in the present embodiment, the third shield portion 31 is in contact with the first and second shield portions 33 and 35 but is not continuously integrated. This hatch design provides greater convenience than conventional techniques for maintaining neutron measuring devices in a hot cell. That is, when the operator who uses or maintains the neutron measuring device opens the hatch-type third shield part 31, the first type simple connector 110 installed in the connection box 100 and the connection box therein, Connected to a type 1 simple connector with a conducting wire cable (not shown), the connection box can be seen by looking directly at the pre-amp 40, the upper end of the detection tube (not shown) connected to the pre-amplifier, and can work.

That is, when the detection tube of a specific position requires replacement, first, the hatch-type third shield portion 31 is opened. Then, the battery amplifier 40 connected to the detection tube visible from the outside while opening the hatch-type third shield portion 31 is pulled apart from the detection tube by using a remote controller (not shown). Then, the end of the exposed detection tube is pulled back to the remote controller and pulled out between the connection box 100 and the moderator 21. The new detection tube to be replaced is installed between the connection box 100 and the moderator 21 through the reverse operation of the detection tube and the reverse operation. At the exposed end of the newly installed detection tube, the preamplifier 40 is also connected via remote controller operation. When the work is completed, the hatch-type third shield portion 31 is closed.

In the present embodiment, the hatch may be divided into two parts from the center to both sides and open to both sides, but may be opened to one side to one part.

5 and 6, a roller 92 is provided at the end of the outer case opening side of the basket 90. As shown in FIG. The roller may be installed on a portion of the bottom of the basket that contacts the inner surface of the blocking body surrounding the basket. Thus, the basket 90 can be easily withdrawn without significant force when operating the remote controller robot arm to withdraw the basket. On the other hand, in this embodiment, the first shield part 35 and the second shield part 33 of the moderator 21 and the shielding body are separated into several pieces, and are modularized. Metals such as lead, which are frequently used as shields, may be difficult to work because their weight is heavy when the shield of the present invention is used as one part. Thus, the modular structure of this embodiment of the present invention facilitates work when the measuring device is installed or detached in a hot cell.

In the present embodiment, the shields 33 and 35 or the moderator 21 are made of pieces having a shape that fit each other in the axial direction, but may be made of pieces that are separated into different shapes.

Looking at the method of mounting or withdrawing the sample in the basket using an embodiment of this configuration, the roller 92 is smooth and easy horizontal movement of the basket 90 compared to the case where the basket 90 is moved by a simple sliding do. Thus, the basket 90 horizontal movement operation by the far-end manipulator robot arm in the relatively low power hot cell can be assisted. Although not shown, the jaw may be formed at the end of the cavity 50 side of the basket 90 and the end of the case opening side of the blocker to which the basket contacts each other. Therefore, even when the basket 90 is pulled outward from the outer case 130 as far as possible, the basket can be prevented from falling out of the outer case, more precisely, beyond the cylindrical surface of the second shield portion 33. .

The basket may be formed of stainless steel, and the space in which the nickel reflector 70 is installed may be integrally formed of stainless steel, and the space in which the graphite reflector 60 is installed may be formed of the same material as the stainless outer case in the outer case. have.

In the upper portion of the cavity 50, the cylinder wall constituting the basket 90 is removed, and when the basket is taken out of the neutron measuring device exterior case 130, the sample container suspended from the crane hook in the hot cell is directly input. Nuclear material having a high level of radioactivity may be placed in a container, or directly mounted in the cavity 50 in the form of an ingot.

Accordingly, in the method of the present invention, when the handle 91 or the hook of the basket is pulled horizontally from the outer case opening side with the robot arm using a remote controller, the basket comes out of the outer case in the state where the basket is installed in the neutron measuring device to expose the cavity part. Done. In the cavity, a container containing a prepared sample is introduced through a hook of a remotely controlled crane. Then, the basket 90 is moved horizontally in the reverse direction through the robot arm and lifted into the outer case of the neutron measuring device. Of course, the above procedure may be reversed when taking out the measured sample out of the measuring device.

FIG. 7 is a view similar to the front view of FIG. 4 but showing one embodiment of the present invention mainly with a connection. Referring to Figure 7, it is possible to generate an output in the form of one TTL pulse per reaction neutron in the detection tube. When the LED of the external LED box 120 flashes at the same time as the output is generated, it is possible to grasp the neutron detection and reaction situation in each detection tube.

The preamplifier 40 may be divided into several groups and may be configured to diagnose an abnormality of the preamplifier 40 and an abnormality of a connection line for connection to the outside. For example, a plurality of preamplifiers may be divided into groups of 5 or 6 and the output signal values of the signal lines separated from each other may be compared with each other to determine whether the signal lines are abnormal. In addition, when an abnormality occurs in the preamplifier, the LDE connected to the preamplifier 40 in the external LED box 120 may be turned off or weakly lighted, and a line or a simple connector for connecting a plurality of preamplifiers in the group ( 110) Alternatively, when an error occurs in the simple connection terminal, the output signal value different from the normal value and the detection strength may be displayed.

8 and 9 illustrate a form in which a connection box and a preamplifier are connected in an embodiment of the present invention.

The preamplifier 40 has a plurality of leads connected to the other side connected to the detection tube 10. Each conductive wire may be formed by dividing into two kinds of signal lines, such as a cable composed of different signal lines such as TTL OUT, TTL IN, LED, and 5 volt lines, and a high voltage line, each of which is simply connected to the connection box 100. Is connected to the connector 110. The simple connectors are again connected to the corresponding simple connectors 110 of the LED box outside the outer case (not shown), and the simple connectors of the LED box are connected to terminals of an external power source or an external device.

Branches consisting of a plurality of conductive wires may be formed of a kind of cable, the end of which may be formed of a multi-terminal multi-stage plug, and the plug may be connected to a simple connector having a plurality of complementary connecting terminals.

The above embodiments are presented to explain the basic or additional features of the present invention and, of course, the present invention is not limited to these embodiments, and it is possible to implement the present invention through various combinations of these features.

According to the present invention has a simple conductor connection structure compared to the conventional device. Therefore, it is easy to maintain and manage the neutron measuring device because only a part of the remote controller can disconnect or reconnect the conductive system connection between the plurality of detectors and the external signal analyzer according to the maintenance needs.

In addition, when the horizontal installation of the device and the installation structure of the hatch are combined, the maintenance of the inspection device can be performed by using the hatch while watching the electronic box, the pre-analyzer, the detection tube, etc. which are the most important for maintenance or management. Maintenance, remote maintenance maintenance work is possible once, can be done conveniently and reliably.

Claims (8)

delete External case, A neutron detector installed in a state surrounded by a moderator in the outer case; At least a portion of the outer case may be exposed through the movement in the outer case, the basket is installed with a cavity for receiving a sample, And an external signal analyzer connected to the detector through a conductive path, At least one one-touch simple connector is installed on the conductive path connecting the detector and the external signal analyzer to an inner space of the outer case. The basket is installed to expose the cavity out of the outer case through a horizontal movement in the outer case. The method of claim 2, At least one portion of the basket is a neutron measuring device, characterized in that a roller for horizontal movement of the basket is installed. The method of claim 2, The basket is a neutron measuring apparatus, characterized in that at least a portion above the cavity is opened upwards to allow the sample to enter and exit freely. The method of claim 2, A neutron measuring device, characterized in that a hatch is opened to open a portion of the outer case to expose the simple connector inside the outer case. The method of claim 5, A radiation shield is installed outside the cavity in an inner space of the outer case including the outer case. At least one of the moderator and the shielding body is a neutron measuring device characterized in that it consists of a plurality of module parts separately mounted along the direction that the surface opened by the hatch toward. The method of claim 2, The outer case is a cylindrical container type with one side open, the cylindrical central axis is installed in a horizontal plane, A shield formed inside the outer case and outside the cavity, the first shield having a cylindrical shape adjacent to the outer case, a second shield provided in a cylindrical shape at a predetermined distance from the first shield, and the first shield; Installed in contact with the one end of the second shield and made of a hatch-type shield that is opened and closed to open the inside from one side, The basket is installed in the axial direction at the center of the outer case into the second shield, The detector is installed in the space between the first shield and the second shield, with one side except for a predetermined section, and the periphery is surrounded by a neutron moderator. The detector has a plurality of detectors in the form of a tube in which both ends are closed horizontally parallel to the basket installation direction along the periphery of the basket, and contains a neutron detection gas, In the space of the predetermined section, a preamplifier and a connection box connected to one end of the detector to process the neutron signal sensed by the detector to be transmitted to the external signal analyzer are installed as part of the conductive path, and the simple connector Is installed in the connection box neutron measuring device, characterized in that connected to the preamplifier. The method of claim 7, wherein The preamplifier is one end of the detector is inserted in the form of a plug neutron measuring device, characterized in that detachable.

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