Burnup measuring device for high-temperature gas cooled reactor anti-coincidence technology

Abstract

The utility model provides a high-temperature gas cooled reactor anti-coincidence technology burnup measuring device, which comprises a main detector used for acquiring a first signal formed by rays radiated into the main detector by a fuel ball in a reactor. The ring detector surrounds at least part of the outer part of the main detector and forms a detection system with the main detector; and the ring detector is used for acquiring a second signal formed in the ring detector by the rays scattered from the main detector. The signal processor is electrically connected with the main detector and the ring detector and is used for processing the first signal and the second signal and screening the signals by judging the generation time sequence of the two types of signals, so that the signal-to-noise ratio can be obviously reduced, and finally higher-quality experimental data can be obtained; the utility model aims to realize safe operation of the nuclear power station, meet the requirement of nuclear material balance and achieve the purpose of nuclear security.

Description

Technical Field

[0001] This application relates to the field of nuclear radiation measurement technology, and in particular to a burnup measurement device for high-temperature gas-cooled reactor anti-coincidence technology. Background Technology

[0002] Non-destructive online burnup measurement is employed in pebble bed high-temperature gas-cooled reactors to support refueling operations without reactor shutdown. The accuracy of online burnup measurement has a significant and crucial impact on the safety and economics of nuclear reactor operation. Fuel burnup depth is typically calculated using Cs-137 activity. In high-activity-level measurement environments, existing burnup measurement devices based on single-lift high-purity germanium gamma-ray spectroscopy systems have low detection rates of characteristic peaks of Cs-137 in irradiated fuel spheres, and the measurement error of Cs-137 activity is relatively high, significantly affecting the effectiveness of the burnup measurement system. Utility Model Content

[0003] This application provides a burnup measurement device for high-temperature gas-cooled reactor anti-combination technology to address the shortcomings of existing technologies.

[0004] This application provides a high-temperature gas-cooled reactor anti-combination technology burnup measurement device, including:

[0005] The main detector is used to acquire the first signal formed by the rays radiated from the fuel spheres inside the reactor and into the main detector.

[0006] A ring detector surrounds at least a portion of the main detector, forming a detection system with the main detector; the ring detector is used to acquire a second signal formed in the ring detector by rays scattered from the main detector.

[0007] A signal processor, electrically connected to the main detector and the ring detector, is used to process the first signal and the second signal.

[0008] Optionally, the side of the ring detector is provided with an entrance hole for the rays to pass through and enter the main detector.

[0009] Optionally, a shielding cover is also included, which is placed outside the ring detector to shield the detection system from radiation emitted from the environment other than that emitted by the fuel ball.

[0010] Optionally, it also includes a collimator, which is connected to the entrance aperture, for guiding the rays emitted by the fuel ball through a preset channel of the collimator into the detection system; at least a portion of the collimator passes through the shield or the shield blocks the gap between the collimator and the detection system.

[0011] Optionally, it may also include a first adjustment component connected to the collimator for adjusting the position of the collimator in the horizontal and vertical directions.

[0012] Optionally, a bracket is also included, which is supported below the shielding cover, with the bottom end of the main detector passing through the bracket.

[0013] Optionally, the bracket includes a base, a support plate, and a top plate, with the support plate connected between the base and the top plate;

[0014] The top plate is supported below the shielding cover, and the top plate has a through hole through which the bottom end of the main detector passes.

[0015] Optionally, a second adjustment component is also included, disposed on the support plate and connected to the main detector, for adjusting the position of the main detector in the horizontal and vertical directions.

[0016] Optionally, a third adjustment component is also included, disposed on the top plate and connected to the ring detector, for adjusting the position of the ring detector in the horizontal and vertical directions.

[0017] Optionally, a limiting member is also included, which is disposed on the top of the bracket. The top surface of the limiting member is provided with a limiting groove, and the bottom of the shielding cover is provided with a protrusion, which is engaged in the limiting groove.

[0018] Optionally, there is one main detector and one ring detector, with the ring detector surrounding the main detector; or

[0019] There is one main detector and multiple ring detectors, with the multiple ring detectors collectively surrounding the main detector; or

[0020] There are multiple main detectors and one ring detector, which surrounds the main detectors; or

[0021] There are multiple main detectors and multiple ring detectors, with each ring detector corresponding to one of the main detectors and surrounding the outside of the main detector.

[0022] The high-temperature gas-cooled reactor anti-coincidence technology burnup measurement device provided in this application, by setting a ring detector around the outside of the main detector, allows the signal processor to process two types of signals generated by the main detector and the ring detector. By determining the generation sequence of the two types of signals, the signals are filtered, thereby significantly reducing the signal-to-noise ratio and ultimately obtaining higher quality experimental data. This is beneficial for achieving safe operation of nuclear power plants, meeting nuclear material balance requirements, and achieving nuclear safety objectives. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments consistent with this application and, together with the description, serve to illustrate the technical solutions of this application.

[0024] Figure 1 This is a schematic diagram of the structure of a high-temperature gas-cooled reactor anti-coincidence technology burnup measurement device, as shown in an exemplary embodiment of this application. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, and to make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent, the technical solutions in the embodiments of this application will be further described in detail below with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0026] See Figure 1 As shown, this application provides a burnup measurement device for a high-temperature gas-cooled reactor using reverse coincidence technology. This device can be used for burnup measurement in a pebble bed type high-temperature gas-cooled reactor, where the reactor may include fuel spheres 90. The burnup measurement device includes:

[0027] The main detector 10 is used to acquire the first signal formed by the radiation from the fuel spheres in the reactor that enters the main detector 10, that is, to acquire the signal formed by the incident radiation passing through the radiation channel and directly entering the main detector 10. Optionally, the main detector 10 can be an HPGe detector, that is, a high-purity germanium detector, which is a nuclear radiation detector made of germanium crystal.

[0028] A ring detector 20 surrounds at least a portion of the main detector 10 to comprehensively detect rays scattered from the main detector 10. The ring detector 20 and the main detector 10 form a detection system. The side of the ring detector 20 has an entrance aperture 21 for the rays to pass through. The ring detector 20 is used to acquire the second signal formed by the rays scattered from the main detector 10 within the ring detector 20, that is, to acquire the signal formed by the rays scattered from the main detector 10 within the ring detector 20. The division between the main detector 10 and the ring detector 20 is functional and logical; in specific implementations, the detection system can simultaneously function as either the main detector or the ring detector.

[0029] A signal processor, electrically connected to the main detector 10 and the ring detector 20, processes the first signal and the second signal, determines and processes the generation sequence of the two types of signals, and filters the signals based on coincidence / anti-coincidence technology. Specifically, the signal processor filters and records the detection signals of the radiation emitted by the fuel sphere by measuring, comparing, and calculating the time characteristics of the signals formed by the main detector 10 and the ring detector 20. Optionally, the main detector 10 and the ring detector 20 may each include electronic components, and the signal processor may include connectors connected to the electronic components of the main detector 10 and the ring detector 20 to achieve electrical connection with the main detector 10 and the ring detector 20.

[0030] In nuclear physics radiation measurements, a coincidence event refers to a situation where, within a specific time resolution, two or more detectors record signals originating from the same physical process or different processes causally related to it, and the detection of these signals is considered a single event. An anticoincidence event, on the other hand, refers to a situation where, within a specific time resolution, the detectors record signals that do not originate from the same physical process or different processes causally related to it. In other words, these signals are not considered a single event because they did not occur simultaneously or have no causal relationship.

[0031] Specifically, this "specific time resolution" is called the coincidence window, which is a time range within which detected signals are considered to have occurred simultaneously. If the signals recorded by the detector fall within this time window, they are determined to be coincidence events; if they exceed this time window, they are considered anti-coincidence events. Coincidence / anti-coincidence measurement techniques are widely used in nuclear physics experiments to eliminate random coincidences (simultaneous occurrence of irrelevant events) and improve the signal-to-noise ratio and measurement accuracy of experimental data.

[0032] The high-temperature gas-cooled reactor anti-coincidence technology burnup measurement device provided in this application, by setting a ring detector 20 around the main detector 10, allows the signal processor to process two types of signals generated by the main detector 10 and the ring detector 20, namely the first signal and the second signal. By determining the generation sequence of the two types of signals, the signals are filtered, thereby enabling online burnup measurement of coincidence / anti-coincidence, obtaining higher quality experimental data with a significantly reduced signal-to-noise ratio. This is beneficial for ensuring the safe operation of nuclear power plants, meeting nuclear material balance requirements, and achieving nuclear safety objectives. Improving the performance of the burnup measurement system enhances the safety and economy of pebble bed high-temperature gas-cooled reactor operation. The anti-coincidence measurement technology can suppress Compton scattering and reduce the background of the characteristic gamma-ray full-energy peak without affecting the full-energy peak itself. Therefore, it can improve the signal-to-noise ratio of the characteristic gamma-ray full-energy peak (including the characteristic gamma rays of Cs-137), thereby increasing the detection rate of the Cs-137 characteristic peak and improving its activity measurement accuracy.

[0033] In some optional implementations, the signal processor has at least the following two types of functions:

[0034] (1) Amplitude analysis (e.g., multichannel analysis) and classification recording function (e.g., multichannel calibration) of detector output signal;

[0035] (2) Extraction of time features (e.g., differentiating circuit), time correlation matching (e.g., delay and comparison) and logic operation functions between signals from different detectors, and feedback and control of whether classification and recording actions are executed.

[0036] It should be noted that the functional requirements of a signal processor are logical and can be implemented by a single signal processor entity or by multiple signal processor entities with complementary functions working together, such as multi-channel scaling and differentiating circuits, which are implemented through multi-entity collaboration.

[0037] In this embodiment, if the signal processor determines that the generation timing of the two types of signals is the same or similar, the signal from the main detector will not be passed to subsequent records. If the signal processor determines that the generation timing of the two types of signals is different, or significantly different, or there is no signal from the loop detector, the signal from the main detector will be passed to subsequent records. That is, the signal processor will remove events that generate signals simultaneously in both the main detector and the loop detector from the classification records.

[0038] In some optional embodiments, the fuel consumption measuring device further includes a shield 30, which is installed outside the ring detector 20 to shield other emitted rays from the environment, except for those emitted by the fuel sphere, from entering the detection system. For example, it shields rays emitted from buildings, air, and the cosmic environment from entering the detection system, thereby reducing the chance of accidental coincidences caused by rays from the environment where the detection system is located or from the object being detected entering the detector system through unexpected channels. Optionally, the shield 30 is primarily composed of high-density materials, combined with materials of different average atomic numbers arranged in a certain order, to achieve better background suppression.

[0039] In some optional embodiments, the fuel consumption measuring device further includes a collimator 40, which mates with the entrance aperture 21 of the ring detector 20, for guiding the rays emitted from the fuel sphere through a predetermined channel of the collimator 40 into the detection system, thereby limiting the intensity of the ray beam entering the main detector 10. At least a portion of the collimator 40 passes through the shield 30, or the shield 30 itself can seal the gap between the collimator 40 and the detection system. It can be understood that the shield 30 serves as a shielding structure, the detection system formed by the ring detector 20 and the main detector 10 is the shielding body, and the shield 30 can seal the gap between the collimator 40 and the shielding body. Optionally, a fuel sphere 90 is provided in the reaction chamber, and a pre-embedded part 91 can be pre-embedded in the side wall of the reaction chamber, penetrating the side wall of the reaction chamber and aligned with the fuel sphere 90. The shield 30 can have a docking hole 31 corresponding to the entrance hole 21 of the ring detector 20. One end of the collimator 40 is aligned with the embedded part 91, and the other end passes through the docking hole 31 of the shield 30 and docks with the entrance hole 21 of the ring detector 20, thereby enabling the rays emitted by the fuel ball 90 to enter the detection system through the preset channel of the collimator 40.

[0040] In some optional embodiments, the fuel consumption measuring device further includes a bracket 70 supported below the shielding cover 30, with the bottom end of the main detector 10 passing through the bracket 70. Specifically, the bracket 70 includes a base 71, a support plate 72, and a top plate 73, with the support plate 72 connecting the base 71 and the top plate 73. The top plate 73 is supported below the shielding cover 30 and has a through hole through which the bottom end of the main detector 10 passes. Casters may be provided at the bottom of the base 71 for easy movement.

[0041] To ensure the stability of the shielding cover 30 and the support 70, a limiting member is provided at the top of the support 70. The top surface of the limiting member has a limiting groove, and the bottom of the shielding cover 30 has a protrusion that engages with the limiting groove, thereby improving the stability of the connection between the shielding cover 30 and the support 70. It should be noted that the shielding cover can also be installed on a floor-standing basis, and its shape can be polygonal, etc.

[0042] In some optional embodiments, the fuel consumption measuring device further includes a first adjustment component 50, a second adjustment component 60, and a third adjustment component. The first adjustment component 50 is connected to the collimator 40 and is used to adjust the position of the collimator 40 in the horizontal and vertical directions. The second adjustment component 60 is disposed on the support plate 72 and connected to the main detector 10, and is used to adjust the position of the main detector 10 in the horizontal and vertical directions. The third adjustment component is disposed on the top plate 73 and connected to the ring detector 20, and is used to adjust the position of the ring detector 20 in the horizontal and vertical directions. By adjusting the positions of the main detector, the ring detector, and the collimator, it is ensured that the collimator can accurately pass through the mating hole of the shield and accurately align with the entrance hole of the ring detector.

[0043] Optionally, the second adjustment assembly 60 may include a first adjustment member 61 arranged laterally, a second adjustment member 62 arranged longitudinally, and a third adjustment member 63 arranged laterally. The third adjustment member 63 is connected to the support plate 72. The second adjustment member 62 can move laterally along the third adjustment member 63, and the first adjustment member 61 can move longitudinally along the second adjustment member 62. The main detector 10 is connected to the first adjustment member 61. The position of the main detector 10 is adjusted by adjusting the positions of the first adjustment member 61 and the second adjustment member 62.

[0044] In some alternative implementations, such as Figure 1 In the example shown, there is one main detector 10 and one ring detector 20, with the ring detector 20 surrounding the main detector 10. Alternatively, there is one main detector 10 and multiple ring detectors 20, with multiple ring detectors 20 collectively surrounding the main detector 10. Alternatively, there are multiple main detectors 10 and one ring detector 20, with the ring detector 20 surrounding the main detector 10. Alternatively, there are multiple main detectors 10 and multiple ring detectors 20, with each ring detector 20 corresponding to one of the main detectors 10.

[0045] It should be noted that the main detector and ring detector in this application can work together in a system where one main detector is combined with one ring detector, or one main detector is combined with multiple ring detectors, or even multiple main detectors are combined with one ring detector, or multiple main detectors are combined with multiple ring detectors. The materials of the main detector and ring detector can be arbitrary, and the structure of the ring detector varies depending on the specific method of the detection system; it can be multiple crystals spliced ​​together, a single crystal, or another method. For a determined detection system, the signal processor includes main signal and gate signal processing sections. The main signal comes from the main detector, and the gate signals are provided by the ring detector. Its ultimate purpose is to determine the selection of the main signal based on the generation timing of the main signal and the gate signals, thereby improving the signal-to-noise ratio.

[0046] The burnup measurement device proposed in this application, applicable to pebble bed high-temperature gas-cooled reactor measurement technology, comprises a main detector specifically used to detect the count signal of incident rays at certain energies after collimation and attenuation by a collimator. A ring detector is specifically used to detect the count signal of incident rays at certain energies after collimation and attenuation by the main detector and collimator. A shield is specifically used to straighten the direction of the collimated incident rays and shield against external ray interference, ensuring that the direction of the rays entering the detector is as singular as possible, reducing interference from other external rays, and decreasing the occurrence of accidental coincidence events. This significantly improves the detection rate of nuclides in the measurement results while significantly reducing experimental measurement errors.

[0047] The measurement geometry is constructed using a mechanical device consisting of a shield, collimator, support, first adjustment assembly, second adjustment assembly, and third adjustment assembly. The interaction signals between the X-rays generated by the main detector and the ring detector are respectively input to the signal processor. The signal processor then performs time-series discrimination on the signals from the main detector and the ring detector, thereby obtaining higher-quality experimental data with a significantly reduced signal-to-noise ratio. Based on the time-matching characteristics of the two types of signals, the signal processor reduces the recording of Compton scattering signals between the X-rays and the detectors by discarding signals generated simultaneously by the main and ring detectors, thereby reducing the detection background of the main detector. This is to ensure the safe operation of the nuclear power plant, meet the requirements of nuclear material balance, and achieve nuclear safety objectives.

[0048] It should be noted that the technical solutions or features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A burnup measurement device for high-temperature gas-cooled reactor reverse-combination technology, characterized in that, include: The main detector is used to acquire the first signal formed by the rays radiated from the fuel spheres inside the reactor and into the main detector. A ring detector surrounds at least a portion of the main detector, forming a detection system with the main detector; The ring detector is used to acquire a second signal formed in the ring detector by the rays scattered from the main detector; A signal processor, electrically connected to the main detector and the ring detector, is used to process the first signal and the second signal.

2. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 1, characterized in that, The ring detector has an entrance hole on its side for the rays to pass through and enter the main detector.

3. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 2, characterized in that, It also includes a shielding cover, which is placed outside the ring detector to shield the detection system from other outgoing rays in the environment, except for those emitted by the fuel ball.

4. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 3, characterized in that, It also includes a collimator, which is connected to the entrance aperture, for guiding the rays emitted by the fuel ball through a pre-set channel of the collimator into the detection system; at least a portion of the collimator passes through the shield or the shield blocks the gap between the collimator and the detection system.

5. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 4, characterized in that, It also includes a first adjustment component, connected to the collimator, for adjusting the position of the collimator in the horizontal and vertical directions.

6. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 3, characterized in that, It also includes a bracket, which is supported below the shielding cover, and the bottom end of the main detector passes through the bracket.

7. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 6, characterized in that, The bracket includes a base, a support plate, and a top plate, with the support plate connected between the base and the top plate; The top plate is supported below the shielding cover, and the top plate has a through hole through which the bottom end of the main detector passes.

8. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 7, characterized in that, It also includes a second adjustment component, which is disposed on the support plate and connected to the main detector, for adjusting the position of the main detector in the horizontal and vertical directions.

9. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 7, characterized in that, It also includes a third adjustment component, which is disposed on the top plate and connected to the ring detector, for adjusting the position of the ring detector in the horizontal and vertical directions.

10. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 6, characterized in that, It also includes a limiting member, which is located on the top of the bracket. The top surface of the limiting member is provided with a limiting groove, and the bottom of the shielding cover is provided with a protrusion, which is engaged in the limiting groove.

11. The high-temperature gas-cooled reactor anti-combination technology burnup measurement device according to claim 1, characterized in that, There is one main detector and one ring detector, with the ring detector surrounding the main detector; or There is one main detector and multiple ring detectors, with the multiple ring detectors collectively surrounding the main detector; or There are multiple main detectors and one ring detector, which surrounds the main detectors; or There are multiple main detectors and multiple ring detectors, with the ring detectors surrounding the main detectors.

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