Nuclear fuel assembly ultrasonic inspection channel expansion device

Abstract

The invention discloses a nuclear fuel assembly ultrasonic inspection channel expansion device which comprises an expansion unit used for being connected between a target ultrasonic instrument and a detection probe; the expansion unit comprises a plurality of excitation expansion channels and a plurality of receiving expansion channels; the control unit is connected between the expansion unit and the target ultrasonic instrument; and the control unit is used for controlling the on-off of the excitation expansion channel and the receiving expansion channel in the expansion unit according to a preset time sequence. By increasing the number of the channels between the ultrasonic instrument and the detection probe, the number of signals which can be received by the ultrasonic instrument is greatly increased on the basis of not increasing the space occupied by the ultrasonic instrument, and each expansion channel can be orderly switched on and switched off through preset time sequence signals, so that the detection efficiency is improved. And a more flexible choice is provided for matching actual use requirements.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic detection, and in particular to a nuclear fuel assembly ultrasonic inspection channel expansion device. Background Art

[0002] Nuclear power plants use the fission reaction of nuclear fuel in the reactor core to generate heat energy for power generation. Nuclear fuel is contained in a sealed thin-walled cladding tube, and the cladding material is zirconium alloy, which is the first barrier to prevent nuclear fuel leakage. The reactor core is in a harsh environment with high radioactivity for a long time. Once the fuel rod is damaged during operation, the radioactive fission products will be released into the coolant of the primary circuit, which will cause a sharp increase in environmental dose and radioactive contamination level, and even cause shutdown, seriously affecting the safety and economy of the nuclear power plant. Its importance is self-evident.

[0003] Currently, the fastest and most effective way to test the metal properties of fuel rods is to perform ultrasonic testing on fuel assemblies. When a fuel rod is damaged, the reactor coolant will enter the fuel rod from the damaged part. However, the fuel assemblies commonly used in nuclear power plants contain multiple fuel rods, which are arranged in a grid and fixed by a variety of grids. If a single-channel ultrasonic instrument is used, multiple ultrasonic inspections are required, which is inefficient. The mainstream ultrasonic instruments on the market generally have only 8 channels. Multi-channel ultrasonic instruments that meet the requirements for fuel assembly testing are not only expensive, but also large in size and difficult to install and operate at nuclear power sites, and difficult to maintain later. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a nuclear fuel assembly ultrasonic inspection channel expansion device.

[0005] The technical solution adopted by the present invention to solve the technical problem is: constructing a nuclear fuel assembly ultrasonic inspection channel expansion device, comprising:

[0006] An expansion unit, used to be connected between the target ultrasonic instrument and the detection probe; the expansion unit includes a plurality of excitation expansion channels and a plurality of receiving expansion channels;

[0007] A control unit is used to be connected between the extension unit and the target ultrasound instrument; the control unit is also used to control the on and off of the excitation extension channel and the receiving extension channel in the extension unit according to a preset timing.

[0008] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed in the present invention, the expansion unit includes at least one excitation channel expansion unit, and also includes a receiving channel expansion unit corresponding to the excitation channel expansion unit;

[0009] The excitation channel expansion unit includes at least two parallel excitation expansion channels; in the same excitation channel expansion unit, the input end of each excitation expansion channel is commonly connected to the same signal transmission interface of the target ultrasound instrument, and the output end of each excitation expansion channel is respectively connected to different excitation probes on the detection probe;

[0010] The receiving channel expansion unit includes at least two parallel receiving expansion channels corresponding to the number of the excitation expansion channels; in the same receiving channel expansion unit, the output end of each receiving expansion channel is commonly connected to the same signal receiving interface of the target ultrasound instrument, and the input end of each receiving expansion channel is respectively connected to different receiving probes on the detection probe.

[0011] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed according to the present invention, the excitation expansion channel and the receiving expansion channel connected to the same detection probe constitute an expansion component, and the control unit sends control signals to each group of the expansion components in turn according to a preset timing.

[0012] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed by the present invention, an optical coupler is provided on the excitation expansion channel; the control signal includes an enable signal;

[0013] The light receiving element of the optical coupler is connected to the target ultrasound instrument and the excitation probe; the light emitting element of the optical coupler is connected to the control unit and changes the working state according to the enabling signal sent by the control unit.

[0014] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed by the present invention, the receiving channel expansion unit includes an analog multiplexer; the control signal includes a line selection signal;

[0015] The analog multiplexer includes a plurality of circuits, and the receiving extension channels correspond to the circuits respectively;

[0016] The input end of the analog multiplexer is connected to several receiving probes, and the output end of the analog multiplexer is connected to the same signal receiving interface of the target ultrasound instrument; the selection end of the analog multiplexer is connected to the control unit, and the analog multiplexer is used to change the on-off state according to the line selection signal sent by the control unit.

[0017] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed by the present invention, the excitation channel expansion unit includes a first excitation expansion channel, a second excitation expansion channel, a third excitation expansion channel and a fourth excitation expansion channel connected in parallel;

[0018] The first excitation extension channel, the second excitation extension channel, the third excitation extension channel and the fourth excitation extension channel are respectively connected to the control unit;

[0019] The control unit sends the control signal to the first excitation extension channel, the second excitation extension channel, the third excitation extension channel and the fourth excitation extension channel in sequence within one cycle, so that the first excitation extension channel, the second excitation extension channel, the third excitation extension channel and the fourth excitation extension channel are respectively turned on for a fixed time.

[0020] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed by the present invention, the receiving channel expansion unit includes a first receiving expansion channel, a second receiving expansion channel, a third receiving expansion channel and a fourth receiving expansion channel connected in parallel;

[0021] The first receiving extension channel, the second receiving extension channel, the third receiving extension channel and the fourth receiving extension channel are respectively connected to the control unit;

[0022] The control unit sends the control signal to the first receiving extension channel, the second receiving extension channel, the third receiving extension channel, and the fourth receiving extension channel in sequence within one cycle, so that the first receiving extension channel, the second receiving extension channel, the third receiving extension channel, and the fourth receiving extension channel are respectively turned on for a fixed time.

[0023] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed in the present invention, the control unit is also used to synchronize the control signal to the target ultrasonic instrument.

[0024] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed by the present invention, it also includes a low-pass filter arranged between the receiving channel expansion unit and the target ultrasonic instrument.

[0025] Preferably, in the nuclear fuel assembly ultrasonic inspection channel expansion device constructed in the present invention, the receiving expansion unit further comprises a variable gain amplifier connected between the receiving expansion channel and the detection probe;

[0026] The input end of the variable gain amplifier is connected to the receiving probe, the output end of the variable gain amplifier is connected to the receiving expansion channel, and the control end of the variable gain amplifier is connected to the control unit;

[0027] The control unit is further configured to output an amplitude modulation command to the variable gain amplifier to change the amplitude of the echo signal input to the receiving channel expansion unit.

[0028] By implementing the present invention, the following beneficial effects are achieved:

[0029] The invention discloses a nuclear fuel assembly ultrasonic inspection channel expansion device, comprising: an expansion unit, used to be connected between a target ultrasonic instrument and a detection probe; the expansion unit comprises a plurality of excitation expansion channels and a plurality of receiving expansion channels; a control unit, connected between the expansion unit and the target ultrasonic instrument; the control unit is used to control the on and off of the excitation expansion channel and the receiving expansion channel in the expansion unit according to a preset timing sequence. By increasing the number of channels between the ultrasonic instrument and the detection probe, the number of signals that can be received by the ultrasonic instrument is greatly increased without increasing the space occupied by the ultrasonic instrument itself, and each expansion channel can be turned on and off in an orderly manner through a preset timing signal, providing a more flexible choice to meet actual use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0031] Figure 1 It is a schematic diagram of the overall structure of the nuclear fuel assembly ultrasonic inspection channel expansion device of the present invention;

[0032] Figure 2 It is a partial structural schematic diagram of the nuclear fuel assembly ultrasonic inspection channel expansion device of the present invention;

[0033] Figure 3 It is a schematic diagram of an optical coupler of a nuclear fuel assembly ultrasonic inspection channel expansion device in the present invention;

[0034] Figure 4 It is a schematic diagram of the nuclear fuel assembly ultrasonic inspection channel expansion device of the present invention when it is working. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0036] It should be noted that the flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor do they have to be executed in the order described. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0037] The block diagrams shown in the accompanying drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0038] See also Figures 1 to 4 The present invention discloses a nuclear fuel assembly ultrasonic inspection channel expansion device, comprising: an expansion unit, used to be connected between a target ultrasonic instrument and a detection probe; the expansion unit comprises a plurality of excitation expansion channels and a plurality of receiving expansion channels; a control unit, used to be connected between the expansion unit and the target ultrasonic instrument; the control unit is also used to control the on and off of the excitation expansion channel and the receiving expansion channel in the expansion unit according to a preset timing.

[0039] The target ultrasonic instrument refers to the ultrasonic instrument whose inspection channel needs to be expanded, and the detection probe is a device that matches the ultrasonic instrument. Usually, to expand the inspection channel of a target ultrasonic instrument, it is only necessary to set a nuclear fuel assembly ultrasonic inspection channel expansion device between the target ultrasonic instrument and a number of detection probes. The connection between the nuclear fuel assembly ultrasonic inspection channel expansion device and the target ultrasonic instrument and the detection probe is a detachable connection, that is, the three are not fixedly connected, and the connection method can be plug-in, magnetic or other. To expand the inspection channel of the target ultrasonic instrument, the number of detection probes matching the target ultrasonic instrument needs to be increased. The number of detection probes corresponds to the number of channels after expansion. One detection probe is connected to an excitation expansion channel and a receiving expansion channel to complete the emission of ultrasound and the reception of echo signals.

[0040] Since the number of inspection channels of the ultrasound instrument itself is limited, while the number of expansion units and detection probes connected to the expansion units can be increased, the control unit is used to control the on and off of the excitation expansion channel and the receiving expansion channel in the expansion unit, and then control the connection relationship between the inspection channel of the ultrasound instrument and different detection probes, thereby achieving the effect of inspecting more target objects.

[0041] In addition, the control unit sends the control timing information and trigger information to the ultrasonic instrument through the synchronization interface. The ultrasonic instrument can determine the detection probe number corresponding to the collection signal based on the synchronization signal, thereby achieving accurate positioning of the damaged fuel rod.

[0042] Furthermore, since the inspection channel configured for each ultrasonic instrument when in use is provided with an excitation channel for connecting to a signal transmitting interface and transmitting ultrasonic signals, and a receiving channel for connecting to a signal receiving interface and transmitting echo signals, the excitation channel and the receiving channel need to be expanded separately. In the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the expansion unit includes at least one excitation channel expansion unit, and also includes a receiving channel expansion unit corresponding to the excitation channel expansion unit; the excitation channel expansion unit includes at least two parallel excitation expansion channels; in the same excitation channel expansion unit, the input end of each excitation expansion channel is commonly connected to the same signal transmitting interface of the target ultrasonic instrument, and the output end of each excitation expansion channel is respectively connected to the excitation probes on different detection probes; the receiving channel expansion unit includes at least two parallel receiving expansion channels corresponding to the number of the excitation expansion channels; in the same receiving channel expansion unit, the output end of each receiving expansion channel is commonly connected to the same signal receiving interface of the target ultrasonic instrument, and the input end of each receiving expansion channel is respectively connected to the receiving probes on different detection probes.

[0043] The excitation channel expansion unit is a structure connected between the signal transmission interface and the excitation probe for increasing the inspection channel. By respectively conducting the excitation expansion channels in the excitation channel expansion unit, the same signal transmission interface is connected to different excitation probes in different time periods, so that ultrasonic signals can be sent to multiple fuel rods in the nuclear fuel assembly at the same signal transmission interface. The same is true for the receiving channel expansion unit, which allows the same signal receiving interface to be connected to different receiving probes in different time periods, so that the same signal receiving interface can receive echo signals fed back by multiple fuel rods in the nuclear fuel assembly.

[0044] Therefore, the ultrasonic inspection channel can be expanded without changing the original structure of the ultrasonic instrument and the ultrasonic inspection effect.

[0045] Furthermore, for the nuclear fuel assembly ultrasonic inspection channel expansion device, a probe assembly with multiple detection probes can be provided in combination, and the number of detection probes in the probe assembly corresponds to the number of excitation channels in the expansion unit. For example, when inspecting a nuclear fuel assembly containing 289 fuel rods arranged in a square grid of 17×17, an ultrasonic expansion device for nuclear fuel assemblies including more than 17 fuel rods is installed between the ultrasonic instrument and the probe assembly containing 17 detection probes, so that the inspection result of the nuclear fuel assembly can be obtained by only one lateral scan.

[0046] Furthermore, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the excitation expansion channel and the receiving expansion channel connected to the same detection probe constitute an expansion component, and the control unit sends a control signal to each group of the expansion components in turn according to a preset timing.

[0047] Furthermore, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, an optical coupler is provided on the excitation expansion channel; the control signal includes an enable signal; the light-receiving element of the optical coupler is connected to the target ultrasonic instrument and the excitation probe; the light-emitting element of the optical coupler is connected to the control unit, and changes the working state according to the enable signal sent by the control unit.

[0048] The ultrasonic excitation signal emitted by the signal transmission interface of the ultrasound instrument is usually a high-voltage signal of 50V to 400V. The withstand voltage of ordinary analog multiplexers is usually only tens of volts, which cannot meet the switching requirements of the excitation signal. In this embodiment, an optical coupler is creatively used to control the timing of the switching of the excitation signal. Preferably, the optical coupler is an optically isolated MOSFET, see Figure 3 , the attached figure shows the internal structure of the optocoupler isolation MOSFET.

[0049] When the control signal is enabled, the light-emitting element (the light-emitting diode in this embodiment) inside the optical coupler emits light after being powered on, causing the MOSFET to turn on, so that the ultrasonic excitation signal is converted into an output signal through the MOSFET, and the output signal acts on the corresponding excitation probe to open the ultrasonic detection channel corresponding to the MOSFET. When the control signal is not enabled, the internal light-emitting diode cannot be turned on, and the MOSFET is cut off, so that the excitation signal cannot be output through the MOSFET. At this time, the output signal is 0V, thereby closing the ultrasonic detection channel corresponding to the MOSFET. Since only one of the MOSFETs in several parallel expansion channels is turned on each time, the ultrasonic excitation signal emitted by the ultrasonic instrument has no loss or attenuation, so that the intensity of the excitation signal reaching the detection probe through the expansion channel is consistent with the intensity of the excitation signal arriving through the original channel.

[0050] See also Figure 4, the control unit controls the expansion timing of the expansion channel: the signal of the first enable port EN1 of the first optical coupler MOSFET1 is pulled high, while the second enable port EN2, the third enable port EN3 and the fourth enable port EN4 are kept low. At this time, the first optical coupler MOSFET1 is turned on, while the second optical coupler MOSFET2, the third optical coupler MOSFET3 and the fourth optical coupler MOSFET4 are in the off state, thereby realizing the excitation of the first detection probe 1. After the first detection probe 1 completes the detection, the voltage levels of the first enable port EN1, the third enable port EN3 and the fourth enable port EN4 are pulled down, and the voltage level of the second enable port EN2 is pulled up. At this time, the second optical coupler MOSFET2 is turned on, and the remaining optical coupler MOSFETs are in the off state, thereby realizing the excitation of the second detection probe 2. Similarly, the serial excitation of the third detection probe 3 and the fourth detection probe 4 is realized respectively, and the scanning is repeated according to the stable timing after the single scan is completed.

[0051] For the timing control of the control unit and the excitation expansion channel, in theory, mechanical switches or other types of fast switches can also be used. However, in the ultrasonic inspection of nuclear fuel assemblies, continuous inspection requires frequent work on this structure. Mechanical switches have high maintenance costs, poor stability, and high noise on site, while the use of photocoupler MOSFET has the advantages of high voltage resistance, long life, and low maintenance cost.

[0052] Furthermore, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the receiving channel expansion unit includes an analog multiplexer; the control signal includes a line selection signal; the analog multiplexer includes a plurality of lines, and the receiving expansion channels correspond to the lines respectively; the input end of the analog multiplexer is connected to a plurality of the receiving probes, and the output end of the analog multiplexer is connected to the same signal receiving interface of the target ultrasonic instrument; the selection end of the analog multiplexer is connected to the control unit, and the analog multiplexer is used to change the on-off state according to the line selection signal sent by the control unit.

[0053] For the signal receiving interface of the ultrasonic instrument, the ultrasonic detection signal passing through the interface is usually only 1mV to 5V. The withstand voltage value of the analog multiplexer (or analog multiplexer) can cover the voltage range of the ultrasonic detection signal. Therefore, the low-voltage detection signal can be switched sequentially by using an analog multiplexer with extremely low loss. In this way, the composition of the nuclear fuel assembly ultrasonic inspection channel expansion device can be met with ready-made electronic devices, and the production steps can be optimized.

[0054] In order to meet the needs of timing switching of signals of different magnitudes, the present invention creatively uses a high-voltage-resistant photoelectric coupling MOSFET for timing switching of high-voltage excitation signals, and uses an analog multiplexer with extremely low loss for timing switching of low-voltage detection signals. The timing switching and matching of the control signals of the excitation extension channel and the receiving extension channel are performed by a single-chip microcomputer to meet the requirements of simultaneously exciting ultrasonic signals and receiving echo signals for a single detection probe, thereby avoiding timing confusion. At the same time, the excitation channel expansion unit and the receiving channel expansion unit can achieve physical isolation of high-voltage excitation signals and low-voltage detection signals, thereby minimizing the interference of high-voltage signals on low-voltage signals and improving the quality of detection signals.

[0055] For a common eight-channel ultrasonic instrument, in order to meet the requirements of efficient inspection of nuclear fuel assemblies, it can be considered to expand it from the original three channels to twelve channels, and the twelve expanded channels and the remaining five original channels can be combined into seventeen inspection channels, or eight original channels can be expanded at the same time. Preferably, in some embodiments, the eight-channel ultrasonic instrument is expanded to thirty-two channels, which can meet the inspection requirements and provide multiple spare channels.

[0056] Further, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the excitation channel expansion unit includes a first excitation expansion channel, a second excitation expansion channel, a third excitation expansion channel and a fourth excitation expansion channel connected in parallel; the first excitation expansion channel, the second excitation expansion channel, the third excitation expansion channel and the fourth excitation expansion channel are respectively connected to the control unit; the control unit sends the control signal to the first excitation expansion channel, the second excitation expansion channel, the third excitation expansion channel and the fourth excitation expansion channel in sequence within a cycle, so that the first excitation expansion channel, the second excitation expansion channel, the third excitation expansion channel and the fourth excitation expansion channel are respectively turned on for a fixed time. In fact, the effect achieved between the four excitation expansion channels in each excitation channel expansion unit is serial communication. By replacing the original channel originally connected to each signal transmission interface of the ultrasonic instrument with four serial expansion channels, the detection capability of each original channel of the ultrasonic instrument can be improved.

[0057] In the specific implementation process, by controlling the timing of sending enable signals by 4 different optical couplers, one excitation signal is applied to the corresponding 4 detection probes in sequence according to the established serial timing, thereby achieving the purpose of converting the excitation signal from 1 to 4. The use of optical couplers to control the timing of the excitation signal can effectively achieve high and low voltage separation. At the same time, the high-voltage excitation signal is physically isolated from the low-voltage detection signal in the circuit design, which greatly reduces the interference of the excitation signal on the detection signal and other low-voltage control circuits.

[0058] Further, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the receiving channel expansion unit includes a first receiving expansion channel, a second receiving expansion channel, a third receiving expansion channel and a fourth receiving expansion channel connected in parallel; the first receiving expansion channel, the second receiving expansion channel, the third receiving expansion channel and the fourth receiving expansion channel are respectively connected to the control unit; the control unit sends the control signal to the first receiving expansion channel, the second receiving expansion channel, the third receiving expansion channel and the fourth receiving expansion channel in sequence within a cycle, so that the first receiving expansion channel, the second receiving expansion channel, the third receiving expansion channel and the fourth receiving expansion channel are respectively turned on for a fixed time. The effect achieved between the four receiving expansion channels in each receiving channel expansion unit is serial communication. By replacing the original channel originally connected to each signal transmission interface of the ultrasonic instrument with four serial expansion channels, the detection capability of each original channel of the ultrasonic instrument can be improved.

[0059] For a receiving channel extension unit including four receiving extension channels, this function can be achieved by using a four-channel analog multiplexer. At this time, the control unit performs conduction control on the analog multiplexer.

[0060] Further, see Figure 4 For a nuclear fuel assembly ultrasonic inspection channel expansion device including four excitation channel expansion units of the excitation expansion channels and four receiving channel expansion units of the receiving expansion channels, one of the excitation channel expansion units and its corresponding receiving channel expansion unit in the nuclear fuel assembly ultrasonic inspection channel expansion device is connected between a signal transmission interface and a corresponding signal receiving interface of the ultrasonic instrument, forming a complete signal transmission and receiving function. Its working principle is as follows:

[0061] When the first enable port EN1 connected to the first excitation extension channel is enabled, the first optical coupler MOSFET1 on the first excitation extension channel is turned on, and the ultrasonic excitation signal sent by the signal transmission interface of the ultrasonic instrument acts on the first detection probe 1, the control unit controls the timing of the analog multiplexer (A0=0, A1=0), so that the first line S1 channel in the analog multiplexer is turned on, and the ultrasonic instrument can complete the signal acquisition of the first detection probe 1. When the second enable port EN2 connected to the second excitation extension channel is enabled, the second optical coupler MOSFET2 on the second excitation extension channel is turned on, and the excitation signal sent by the signal transmission interface of the ultrasonic instrument acts on the second detection probe 2, the control unit controls the timing of the analog multiplexer (A0=1, A1=0), so that the second line S2 channel in the analog multiplexer is turned on, and the ultrasonic instrument can complete the signal acquisition of the second detection probe 2. When the third enable port EN3 on the third excitation extension channel is enabled, the third optical coupler MOSFET3 is turned on, and the excitation signal acts on the third detection probe 3, the control unit controls the analog multiplexer timing (A0=0, A1=1) to turn on the third line S3 channel of the analog multiplexer, and the ultrasound instrument can complete the signal acquisition of the third detection probe 3. When the fourth enable port EN4 on the fourth excitation extension channel is enabled, the fourth optical coupler MOSFET4 is turned on, and the excitation signal acts on the fourth detection probe 4, the control unit controls the analog multiplexer timing (A0=1, A1=1) to turn on the fourth line S4 channel of the analog multiplexer, and the ultrasound instrument can complete the signal acquisition of the fourth detection probe 4.

[0062] According to this control timing, the detection probes involved are subjected to cyclic signal acquisition to meet the requirement of continuous signal acquisition of the detection probes, which neither increases the auxiliary structure with excessive volume nor requires the modification of the circuit of the ultrasonic instrument itself. If a third control port A2 is added in addition to the first control port A0 and the second control port A1 of the analog multiplexer, and a corresponding number of excitation extension channels are added to the excitation channel extension unit, the same original channel of the ultrasonic instrument can be expanded into more extension channels. For other signal transmitting interfaces of the ultrasonic instrument and the signal receiving interfaces corresponding to these signal transmitting interfaces, the same extension structure and working principle can also be used to expand the inspection channels, which will not be repeated here.

[0063] Furthermore, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the control unit is also used to synchronize the control signal to the target ultrasonic instrument. Since the channel expansion scheme adopted is controlled according to a preset timing, the control timing and related trigger signals need to be fed back to the ultrasonic instrument, and the synchronization of the control signal is sent to the target ultrasonic instrument through a synchronization interface. In some embodiments, the ultrasonic instrument can determine the detection probe number corresponding to the echo signal based on the synchronization signal, thereby realizing the precise positioning of the damaged fuel rod.

[0064] Furthermore, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, a low-pass filter is also provided between the receiving channel expansion unit and the target ultrasonic instrument. The echo signal output by the analog multiplexer carries a lot of high-frequency clutter. After adding a low-pass filter to the circuit, these interference signals can be effectively filtered out, further improving the quality of the received signal.

[0065] Furthermore, the ultrasonic echo signal on the detection probe is very weak in itself. If it passes through a long transmission line, it will be attenuated. When the detection signal is attenuated to a certain extent, it will become an invalid signal. Amplifying the received echo signal can enhance its anti-attenuation ability, and the calibration requirements in some inspection tasks need to be achieved by adjusting the receiving amplitude. Therefore, in the nuclear fuel assembly ultrasonic inspection channel expansion device disclosed in this embodiment, the receiving expansion unit also includes a variable gain amplifier connected between the receiving expansion channel and the detection probe. The input end of the variable gain amplifier is connected to the receiving probe, the output end of the variable gain amplifier is connected to the receiving expansion channel, and the control end of the variable gain amplifier is connected to the control unit. Accordingly, the control unit is also used to output an amplitude modulation command to the variable gain amplifier to change the amplitude of the echo signal input to the receiving channel expansion unit.

[0066] For different inspection tasks, the control unit and the target ultrasound instrument communicate bidirectionally through the network port to exchange relevant information of the ultrasound scan. For example, in order to meet the calibration requirements, when organizing the ultrasonic scanning of nuclear fuel assemblies, the control unit and the target ultrasound instrument exchange the scanning task requirements, and the control unit analyzes the obtained scanning task requirements and controls the corresponding variable gain amplifier to respond, thereby realizing the amplitude adjustment of each receiving expansion channel. Among them, the control unit can be a single-chip microcomputer.

[0067] Furthermore, when ultrasonically scanning the fuel assembly, the detection signal calibration is required, and the amplitude of the signal received by each channel needs to be adjusted to meet the calibration requirements. To meet the above requirements, the target ultrasonic instrument can send commands to the single-chip microcomputer in the device through the network interface, and the single-chip microcomputer analyzes the commands and controls the corresponding VGA to respond, thereby realizing the amplitude adjustment of each received signal.

[0068] By implementing the present invention, the following beneficial effects are achieved:

[0069] 1) The disclosed nuclear fuel assembly ultrasonic inspection channel expansion device can expand a conventional 8-channel ultrasonic instrument to 32 channels or even more, meeting the requirements for the number of ultrasonic channels in ultrasonic scanning of fuel assemblies.

[0070] 2) The disclosed nuclear fuel assembly ultrasonic inspection channel expansion device has a small size, a simple interface, and is easy to install and maintain on site.

[0071] 3) The disclosed nuclear fuel assembly ultrasonic inspection channel expansion device is cheap, and the ultrasonic instrument matched therewith is a general-purpose device, which is also cheap, thus greatly reducing the cost of production equipment.

[0072] 4) The disclosed nuclear fuel assembly ultrasonic inspection channel expansion device can match the mainstream ultrasonic instrument, does not need to add additional circuits, is simple to apply and set up, and has high versatility. It greatly broadens the selection range of ultrasonic instruments and avoids being monopolized by foreign suppliers.

[0073] 5) The disclosed nuclear fuel assembly ultrasonic inspection channel expansion device has strong anti-interference capability. The high-voltage excitation signal and the low-voltage acquisition signal are physically isolated in the design to prevent the receiving channel from being interfered by the high-voltage excitation signal, which greatly improves the overall anti-interference capability of the system.

[0074] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above embodiments or technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention, that is, the embodiments described in "some embodiments" can be freely combined with any of the above and below embodiments. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A nuclear fuel assembly ultrasonic inspection channel expansion device, characterized in that: include: An expansion unit, used to be connected between the target ultrasonic instrument and the detection probe; the expansion unit includes a plurality of excitation expansion channels and a plurality of receiving expansion channels; A control unit is used to be connected between the extension unit and the target ultrasound instrument; the control unit is also used to control the on and off of the excitation extension channel and the receiving extension channel in the extension unit according to a preset timing.

2. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 1, characterized in that: The expansion unit includes at least one excitation channel expansion unit, and also includes a receiving channel expansion unit arranged corresponding to the excitation channel expansion unit; The excitation channel expansion unit includes at least two parallel excitation expansion channels; in the same excitation channel expansion unit, the input end of each excitation expansion channel is commonly connected to the same signal transmission interface of the target ultrasound instrument, and the output end of each excitation expansion channel is respectively connected to different excitation probes on the detection probe; The receiving channel expansion unit includes at least two parallel receiving expansion channels corresponding to the number of the excitation expansion channels; in the same receiving channel expansion unit, the output end of each receiving expansion channel is commonly connected to the same signal receiving interface of the target ultrasound instrument, and the input end of each receiving expansion channel is respectively connected to different receiving probes on the detection probe.

3. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 1, characterized in that: The excitation extension channel and the receiving extension channel connected to the same detection probe constitute an extension component, and the control unit sends a control signal to each group of the extension components in sequence according to a preset timing.

4. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 3, characterized in that: The excitation extension channel is provided with an optical coupler; the control signal includes an enable signal; The light receiving element of the optical coupler is connected to the target ultrasound instrument and the excitation probe; the light emitting element of the optical coupler is connected to the control unit and changes the working state according to the enabling signal sent by the control unit.

5. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 3, characterized in that: The receiving channel expansion unit includes an analog multiplexer; the control signal includes a line selection signal; The analog multiplexer includes a plurality of circuits, and the receiving extension channels correspond to the circuits respectively; The input end of the analog multiplexer is connected to several receiving probes, and the output end of the analog multiplexer is connected to the same signal receiving interface of the target ultrasound instrument; the selection end of the analog multiplexer is connected to the control unit, and the analog multiplexer is used to change the on-off state according to the line selection signal sent by the control unit.

6. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 3, characterized in that: The excitation channel expansion unit comprises a first excitation expansion channel, a second excitation expansion channel, a third excitation expansion channel and a fourth excitation expansion channel connected in parallel; The first excitation extension channel, the second excitation extension channel, the third excitation extension channel and the fourth excitation extension channel are respectively connected to the control unit; The control unit sends the control signal to the first excitation extension channel, the second excitation extension channel, the third excitation extension channel and the fourth excitation extension channel in sequence within one cycle, so that the first excitation extension channel, the second excitation extension channel, the third excitation extension channel and the fourth excitation extension channel are respectively turned on for a fixed time.

7. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 3, characterized in that: The receiving channel expansion unit includes a first receiving expansion channel, a second receiving expansion channel, a third receiving expansion channel and a fourth receiving expansion channel connected in parallel; The first receiving extension channel, the second receiving extension channel, the third receiving extension channel and the fourth receiving extension channel are respectively connected to the control unit; The control unit sends the control signal to the first receiving extension channel, the second receiving extension channel, the third receiving extension channel, and the fourth receiving extension channel in sequence within one cycle, so that the first receiving extension channel, the second receiving extension channel, the third receiving extension channel, and the fourth receiving extension channel are respectively turned on for a fixed time.

8. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 3, characterized in that: The control unit is further configured to synchronize the control signal to the target ultrasound instrument.

9. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 1, characterized in that: The receiving extension unit also includes a variable gain amplifier connected between the receiving extension channel and the detection probe; The input end of the variable gain amplifier is connected to the receiving probe, the output end of the variable gain amplifier is connected to the receiving expansion channel, and the control end of the variable gain amplifier is connected to the control unit; The control unit is further configured to output an amplitude modulation command to the variable gain amplifier to change the amplitude of the echo signal input to the receiving channel expansion unit.

10. The nuclear fuel assembly ultrasonic inspection channel expansion device according to claim 2, characterized in that: It also includes a low-pass filter arranged between the receiving channel expansion unit and the target ultrasound instrument.

Images