Integrated coaxial multilayer annular emitter self-powered detector

Abstract

This invention discloses an integrated coaxial multi-layered annular emitter self-powered detector, comprising a probe, a connecting sleeve, and a transmission cable. The probe includes a collector, an insulating layer, and an emitter arranged coaxially from the outside in. The insulating layer includes a side insulating layer, a bottom insulating layer, a top insulating layer, and insulators. Multiple insulators and emitters are present, and the emitters and insulators are alternately stacked coaxially to form a sandwich structure. The transmission cable includes a cable shell and cable cores, with an insulating layer filling the space between the cable shell and the cable cores. There are multiple cable cores, each connected to a corresponding emitter. The connecting sleeve is an annular structure with different diameters at both ends; the larger end is welded to the open end of the collector, and the smaller end is welded to the cable shell. This invention enables the measurement of neutron flux distribution and neutron energy spectrum under the confined space of a reactor core.

Description

Technical Field

[0001] This invention relates to the field of fourth-generation reactor neutron detection technology, specifically to an integrated coaxial multi-layered annular emitter self-powered detector suitable for neutron flux distribution measurement and energy spectrum measurement in high-temperature and high-pressure reactor core environments. Background Technology

[0002] Currently, reactor neutron monitoring technology faces core challenges such as insufficient accuracy in flux distribution measurement and lack of real-time energy spectrum monitoring, and these problems are particularly prominent under the extreme operating conditions of fourth-generation advanced reactors.

[0003] In terms of neutron flux distribution measurement, existing technologies use multiple discrete detectors (such as self-powered neutron detector SPND groups or micro-fission chambers) arranged along the core axis to form a measurement array. Each detector requires independent leads, shielding and sealing structures. The risk of wiring conflicts in the small space of the core is significant, resulting in excessive system complexity.

[0004] In neutron spectroscopy measurements, existing techniques commonly employ methods such as the activated foil method and the fission chamber combination method. The activated foil method requires inserting a metal foil (such as In or Cu) into the reactor core for several hours of irradiation, followed by offline analysis using a gamma spectrometer. This results in a single measurement cycle exceeding 24 hours, making it unable to capture transient conditions (such as sudden power surges). The fission chamber combination method requires simultaneous use of... 235 U (thermal neutron sensitive) 238 There are various types of ionization chambers, such as U (fast neutron sensitive), but the ionization efficiency of the filling gas drops sharply at temperatures above 400°C, and the risk of breakdown of high-voltage insulators increases dramatically under high gamma dose rates, making them unsuitable for detection in the high-temperature, confined space of the reactor core.

[0005] For fourth-generation reactors (such as sodium-cooled fast reactors and molten salt reactors) under extreme operating conditions (>500℃ high temperature, >15MPa high pressure and >10...), 14 (n / cm2·s fast neutron irradiation), existing detectors are unsuitable due to material degradation, signal interference, and structural failure.

[0006] Therefore, the existing technology system, under the triple constraints of separate measurement functions (flux distribution and energy spectrum need to be independent systems), insufficient environmental tolerance, and excessive space occupation, cannot meet the core monitoring requirements of miniaturized, integrated, and highly reliable fourth-generation reactors, and there is an urgent need to develop new detector technologies. Summary of the Invention

[0007] This invention addresses the aforementioned problems of existing self-powered neutron detectors by providing an integrated coaxial multi-layered annular emitter self-powered detector for measuring neutron flux distribution and neutron energy spectrum in reactor cores. This detector enables neutron flux distribution and energy spectrum measurements within the confined space of the reactor core under high temperature, high pressure, and strong radiation conditions. It features strong radiation resistance, is entirely solid-state, withstands high temperature and high pressure, and requires no external power source.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The integrated coaxial multi-layer ring-shaped emitter self-powered detector provided by the present invention includes a probe, a connecting sleeve, and a transmission cable. The probe includes a collector, an insulating layer, and an emitter arranged coaxially from the outside to the inside. The collector has a cylindrical structure with one end being a closed end and the other end being an open end.

[0010] The insulating layer includes a side insulating layer, a bottom insulating layer, a top insulating layer, and an insulator. The side insulating layer, bottom insulating layer, and top insulating layer form a closed structure and are located inside the collecting body. There are multiple insulators.

[0011] The number of emitters is multiple, and the emitters and insulators are stacked alternately on the same axis to form a sandwich structure and are located inside the closed structure of the insulation layer;

[0012] The transmission cable includes a cable shell and cable cores, with a cable insulation layer filling the space between the cable shell and the cable cores. There are multiple cable cores, and each cable core is connected to a transmitter.

[0013] The connecting sleeve is a ring structure with different diameters at both ends. The larger end is welded to the opening of the collecting body, and the smaller end is welded to the cable shell.

[0014] Preferably, both the emitter and the insulator are ring-shaped structures, and the inner and outer diameters of the emitter and the insulator are the same.

[0015] Optionally, all emitters are made of the same size and material of metal for neutron flux distribution measurement.

[0016] Optionally, each emitter may be made of the same or different sizes and materials of metal for neutron energy spectrum measurement.

[0017] Preferably, the number of transmitters is four, including a first transmitter, a second transmitter, a third transmitter, and a fourth transmitter, and the number of cable cores is four, including a first core wire, a second core wire, a third core wire, and a fourth core wire. The first core wire, the second core wire, the third core wire, and the fourth core wire are respectively connected to the inner walls of the first transmitter, the second transmitter, the third transmitter, and the fourth transmitter.

[0018] Optionally, the thickness of the closed end of the collecting body is 5-10 mm, and the collecting body is made of Inconel600 material.

[0019] Optionally, the side insulating layer has a cylindrical structure, the bottom insulating layer has a disc-shaped structure, and the top insulating layer has a disc-shaped structure with a central through hole. The insulating layers are made of alumina material.

[0020] Optionally, the cable shell and cable core are made of Inconel 600 material, and the cable insulation layer is made of aluminum oxide material.

[0021] Optionally, the connecting sleeve is made of Inconel 600 material.

[0022] Beneficial technical effects of the present invention:

[0023] 1. The integrated coaxial multi-layer ring emitter self-powered detector of the present invention, through the coaxial arrangement of multiple emitters in a single probe, realizes the measurement of neutron flux distribution and neutron energy spectrum under high temperature, high pressure and strong irradiation conditions and in the confined space of the reactor core. Its all-solid-state structure can withstand the extreme environment of the reactor core and has the advantages of high temperature resistance, high pressure resistance, irradiation resistance, miniaturization, high integration and no need for external power supply.

[0024] 2. Compared with the existing scheme of using multiple detectors to form an assembly system for core neutron flux distribution measurement, the detector of the present invention uses multiple homogeneous emitters to form an array to provide axial spatial resolution, realize neutron flux distribution detection in one dimension, greatly simplify the measurement complexity and reduce the cost of using the detector.

[0025] 3. Current neutron energy spectrum detection technologies cannot achieve neutron energy spectrum measurement under high temperature, high pressure, and strong irradiation conditions. The measurement cycle of activated foil is too long, and fission ionization chambers are not suitable for detection in the high temperature and confined space of the reactor core. The detector of this invention uses multiple heterogeneous emitters and utilizes the response matrix combined with the spectral decomposition algorithm to invert the energy spectrum in real time, completely eliminating the dependence on multiple detectors. It realizes the measurement of neutron energy spectrum using a single detector in the confined space of the reactor core under high temperature, high pressure, and strong irradiation conditions. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1This is a schematic diagram of the structure of the integrated coaxial multi-layer ring emitter self-powered detector in this invention.

[0028] Figure 2 This is a diagram showing the internal structure of the integrated coaxial multi-layered annular emitter self-powered detector of the present invention.

[0029] Figure 3 for Figure 2 Sectional view along line AA;

[0030] Figure 4 In Example 2 103 Rh+n→ 104 Cross-sectional diagram of nuclear reactions in Rh;

[0031] Figure 5 In Example 2 51 V+n→ 52 Cross-sectional diagram of nuclear reaction in V;

[0032] Figure 6 In Example 2 107 Ag+n→ 108 Cross-sectional diagram of nuclear reaction of Ag;

[0033] Figure 7 In Example 2 109 Ag+n→ 110 Cross-sectional diagram of nuclear reaction of Ag;

[0034] Figure 8 In Example 2 9 Be+n→ 6 Cross-sectional diagram of the nuclear reaction of He+α;

[0035] Figure label:

[0036] 1-Probe; 2-Connecting sleeve; 3-Transmission cable;

[0037] 11-Collector; 12-Insulating layer; 13-Emitter;

[0038] 121 - Side insulation layer; 122 - Bottom insulation layer; 123 - Top insulation layer; 124 - Insulator;

[0039] 131 - First launcher; 132 - Second launcher; 133 - Third launcher; 134 - Fourth launcher.

[0040] 31-Cable outer shell; 32-Cable insulation layer; 33-Cable core wire;

[0041] 331 - First core wire; 332 - Second core wire; 333 - Third core wire; 334 - Fourth core wire. Detailed Implementation

[0042] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0043] Example 1

[0044] Figure 1 This is a schematic diagram of the structure of the integrated coaxial multi-layer ring emitter self-powered detector in this invention. Figure 2 This is a diagram showing the internal structure of the integrated coaxial multi-layered annular emitter self-powered detector of the present invention. Figure 3 for Figure 2 Sectional view along line AA.

[0045] like Figure 1-2 As shown, the integrated coaxial multi-layer ring-shaped emitter self-powered detector of this embodiment consists of a probe 1, a connecting sleeve 2, and a transmission cable 3. The connecting sleeve 2 connects the probe 1 and the transmission cable 3 to form a whole, and the connection is sealed by welding. The probe 1 includes a collector 11, an insulating layer 12, and an emitter 13 arranged coaxially from the outside to the inside.

[0046] like Figure 2-3 As shown, the collecting body 11 is a cylindrical structure with one end closed and the other end open; the insulating layer 12 includes a side insulating layer 121, a bottom insulating layer 122, a top insulating layer 123, and an insulator 124. The side insulating layer 121, the bottom insulating layer 122, and the top insulating layer 123 form a closed structure and are located inside the collecting body 11. There are 3 insulators 124.

[0047] like Figure 2-3 As shown, there are four transmitters 13. Both transmitters 13 and insulators 124 are ring structures. The transmitters 13 and insulators 124 are stacked alternately on the same axis to form a sandwich structure and are located inside the closed structure of the insulation layer 12. The transmission cable 3 includes a cable shell 31 and a cable core 33. The cable shell 31 and the cable core 33 are filled with a cable insulation layer 32. There are multiple cable cores 33, and each cable core 33 is connected to a transmitter 13. The connecting sleeve 2 is a ring structure with different diameters at both ends. The larger end is welded to the open end of the collector 11, and the smaller end is welded to the cable shell 31.

[0048] like Figure 2-3As shown, the transmitter 13 is composed of a first transmitter 131, a second transmitter 132, a third transmitter 133, and a fourth transmitter 134 arranged coaxially and equidistantly from bottom to top. The number of cable cores 33 is 4, including the first core 331, the second core 332, the third core 333, and the fourth core 334. The first core 331, the second core 332, the third core 333, and the fourth core 334 are respectively welded to the inner walls of the first transmitter 131, the second transmitter 132, the third transmitter 133, and the fourth transmitter 134.

[0049] In this embodiment, the collecting body 11 is made of Inconel 600 material, with an outer diameter of 10mm, an inner diameter of 9mm, an outer length of 500mm, an inner depth of 490mm, and a closed end thickness of 10mm; the side insulating layer 121 is made of alumina material, processed into a cylindrical shape, with an outer diameter of 8.95mm, an inner diameter of 8mm, and a length of 470mm; the bottom insulating layer 122 is made of alumina material, processed into a disc shape, with an outer diameter of 8.95mm and a thickness of 10mm; the top insulating layer 123 is made of alumina material, processed into a disc shape, with an outer diameter of 8.95mm and a thickness of 10mm; the insulator 124 is made of alumina material, processed into a cylindrical shape, with an outer diameter of 7.95mm, an inner diameter of 6mm, and a length of... 130mm; the first transmitter 131, the second transmitter 132, the third transmitter 133, and the fourth transmitter 134 are all made of rhodium (Rh), all machined into annular shapes, with the same dimensions: an outer diameter of 7.95mm, an inner diameter of 6mm, and a length of 20mm; the connecting sleeve 2 is made of Inconel 600 material, and is a cylindrical shape with different sizes at both ends: the outer diameter of the larger end is 10mm, the outer diameter of the smaller end is 8mm, the diameter of the central through hole is 6.05mm, and the height is 10mm; the transmission cable is circular, a 4-core coaxial cable with an outer diameter of 6mm, the cable outer shell 31 is made of Inconel 600 material, the cable insulation layer 32 is made of alumina material, and the cable core wire 33 is made of Inconel 600 material.

[0050] The integrated coaxial multi-layered annular emitter self-powered detector of this embodiment is used for neutron flux distribution measurement. Its neutron flux distribution detection principle is as follows: When the probe portion of the integrated coaxial multi-layered annular emitter self-powered detector extends into the reactor core, the probe portion... 103 Rh emitter materials undergo nuclear reactions when irradiated with neutrons, generating radioactive nuclides. 104 Rh, a radionuclide 104 Rh undergoes beta decay, emitting beta electrons. These beta electrons pass through the insulating layer and are collected by a collector, a process that generates a current signal. The magnitude of this current signal is proportional to the number of beta electrons and the number of neutrons, so the neutron flux can be calculated from the current magnitude.

[0051] Since there are four Rh emitters of the same material and size in the detector, and the four emitters are located in the same dimensional direction but at different positions, four current signals are generated in the back-end electronics. The four current signals correspond to the neutron flux at four different positions, thus realizing the measurement of neutron flux distribution.

[0052] Example 2

[0053] like Figure 1-2 As shown, the integrated coaxial multi-layer ring-shaped emitter self-powered detector of this embodiment consists of a probe 1, a connecting sleeve 2, and a transmission cable 3. The connecting sleeve 2 connects the probe 1 and the transmission cable 3 to form a whole, and the connection is sealed by welding. The probe 1 includes a collector 11, an insulating layer 12, and an emitter 13 arranged coaxially from the outside to the inside.

[0054] like Figure 2-3 As shown, the collecting body 11 is a cylindrical structure with one end closed and the other end open; the insulating layer 12 includes a side insulating layer 121, a bottom insulating layer 122, a top insulating layer 123, and an insulator 124. The side insulating layer 121, the bottom insulating layer 122, and the top insulating layer 123 form a closed structure and are located inside the collecting body 11. There are 3 insulators 124.

[0055] like Figure 2-3 As shown, there are four transmitters 13. Both transmitters 13 and insulators 124 are ring structures. The transmitters 13 and insulators 124 are stacked alternately on the same axis to form a sandwich structure and are located inside the closed structure of the insulation layer 12. The transmission cable 3 includes a cable shell 31 and a cable core 33. The cable shell 31 and the cable core 33 are filled with a cable insulation layer 32. There are multiple cable cores 33, and each cable core 33 is connected to a transmitter 13. The connecting sleeve 2 is a ring structure with different diameters at both ends. The larger end is welded to the open end of the collector 11, and the smaller end is welded to the cable shell 31.

[0056] like Figure 2-3 As shown, the transmitter 13 is composed of a first transmitter 131, a second transmitter 132, a third transmitter 133, and a fourth transmitter 134 arranged coaxially and equidistantly from bottom to top. The number of cable cores 33 is 4, including the first core 331, the second core 332, the third core 333, and the fourth core 334. The first core 331, the second core 332, the third core 333, and the fourth core 334 are respectively welded to the inner walls of the first transmitter 131, the second transmitter 132, the third transmitter 133, and the fourth transmitter 134.

[0057] In this embodiment, the collecting body 11 is made of Inconel 600 material, with an outer diameter of 10mm, an inner diameter of 9mm, an outer length of 190mm, an inner depth of 185mm, and a closed end thickness of 5mm; the side insulating layer 121 is made of alumina material, processed into a cylindrical shape, with an outer diameter of 8.95mm, an inner diameter of 8mm, and a length of 175mm; the bottom insulating layer 122 is made of alumina material, processed into a disc shape, with an outer diameter of 8.95mm and a thickness of 5mm; the top insulating layer 123 is made of alumina material, processed into a disc shape, with an outer diameter of 8.95mm and a thickness of 5mm; the insulator 124 is made of alumina material, processed into a cylindrical shape, with an outer diameter of 7.95mm, an inner diameter of 6mm, and a length of 5mm; the first emitter 131 is made of rhodium (Rh), processed into a ring shape, with an outer diameter of 7.95mm, an inner diameter of 6mm, and a length of 30mm; The second emitter 132 is made of silver (Ag), machined into a ring shape with an outer diameter of 7.95 mm, an inner diameter of 6 mm, and a length of 40 mm; the third emitter 133 is made of vanadium (V), machined into a ring shape with an outer diameter of 7.95 mm, an inner diameter of 6 mm, and a length of 40 mm; the fourth emitter 134 is made of beryllium (Be), machined into a ring shape with an outer diameter of 7.95 mm, an inner diameter of 6 mm, and a length of 50 mm; the connecting sleeve 2 is made of Inconel 600 material, and is a cylindrical shape with different sizes at both ends, with an outer diameter of 10 mm at the larger end, an outer diameter of 8 mm at the smaller end, a through-hole diameter of 6.05 mm in the center, and a height of 5 mm; the transmission cable is circular, a 4-core coaxial cable with an outer diameter of 6 mm, the cable outer shell 31 is made of Inconel 600 material, the cable insulation layer 32 is made of alumina material, and the cable core wire 33 is made of Inconel 600 material.

[0058] The integrated coaxial multi-layered annular emitter self-powered detector of this embodiment is used for neutron energy spectrum detection. The neutron energy spectrum detection principle is as follows: When the probe part of the integrated coaxial multi-layered annular emitter self-powered detector is inserted into the reactor core, the probe part undergoes a nuclear reaction after being irradiated by the neutron field to be measured. Rhodium, silver, vanadium, and beryllium undergo a radiation capture reaction after being irradiated by neutrons, generating radioactive nuclides. The reaction process is as follows:

[0059] n+ 103 Rh→ 104 Rh→ 104 Pd+β;

[0060] n+ 107 Ag→ 108 Ag→ 108 Cd+β;

[0061] n+ 109 Ag→110Ag→110Cd+β;

[0062] n+ 51 V→ 52 V→ 52 Cr+β;

[0063] n+ 9 Be → 6 He+α; 6 He→ 6 Li+β;

[0064] Radioactive nuclides undergo beta decay, emitting beta electrons. These beta electrons are collected by the collector after passing through the insulating layer, generating a current signal. Since the detector contains four emitters made of different materials, each with a different response cross-section to neutrons of varying energies, four different current signals are generated in the back-end electronics. Based on these multiple current signals and the overall detector response matrix, the neutron energy spectrum is ultimately detected through a spectral analysis system.

[0065] In neutron energy spectrum detection, the neutron energy spectrum is generally discretized from a continuous spectrum into multiple energy regions. The neutron energy spectrum is then deconstructed by solving for the proportions of different energy regions. In this example, four different emitters—Rh, V, Ag, and Be—were used. Based on the differences in the response cross-sections of different annular emitter materials to neutron energy (e.g., rhodium is sensitive to thermal neutrons, while beryllium is sensitive to fast neutrons), the multiple current signals output by the detector constitute a set of response equations. An emitter-energy region response matrix R was established through Monte Carlo simulation and experimental calibration. The continuous neutron energy spectrum was discretized into four energy regions: hot (<0.5 eV), ultra-hot (0.5 eV–10 keV), medium (10 keV–0.1 MeV), and fast (>0.1 MeV). The equation I=RP was solved to invert the flux proportion Pj of each energy region, and the continuous energy spectrum P(E) was reconstructed by combining energy spectrum normalization.

[0066]

[0067] like Figure 4-8 As shown, in nuclear reaction cross-section measurements, the reaction cross-section characteristics of four materials—Rh, V, Ag, and Be—commonly cover the entire energy range, and significant differences exist in the cross-sections of each material within each energy range. In the hot region, 103 Rh、 51 V. 107 Ag and 109 The cross-sections of Ag exhibit different values. 103 The thermal neutron cross-section of Rh is approximately 143 barn. 51 The thermal neutron cross-section of V is approximately 5 barn. 107 The thermal neutron cross-section of Ag is approximately 38 barn. 109The thermal neutron cross section of Ag is approximately 90 barn; it enters the medium energy region (10 keV–0.1 MeV). 51 A distinct resonance peak appears at around 10 keV, while 103 Rh、 107 Ag and 109 The cross-section of Ag gradually decreases; while in the fast region (>0.1 MeV)... 9 The cross-section of Be tends to stabilize, reaching a peak of 0.105 barn at 3 MeV, while the reaction cross-sections of other materials decrease sharply.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the technical solution and conceptual invention of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated coaxial multi-layered annular emitter self-powered detector, comprising a probe, a connecting sleeve, and a transmission cable, wherein the probe comprises a collector, an insulating layer, and an emitter arranged coaxially from the outside to the inside; the collector is a cylindrical structure with one closed end and the other open end; characterized in that: The insulating layer includes a side insulating layer, a bottom insulating layer, a top insulating layer, and an insulator. The side insulating layer, bottom insulating layer, and top insulating layer form a closed structure and are located inside the collecting body. There are multiple insulators. The number of emitters is multiple, and the emitters and insulators are stacked alternately on the same axis to form a sandwich structure and located inside the closed structure of the insulation layer; both the emitters and the insulators are ring structures, and the inner diameter and outer diameter of the emitters and the insulators are the same. The transmission cable includes a cable shell and cable cores, with a cable insulation layer filling the space between the cable shell and the cable cores. There are multiple cable cores, and each cable core is connected to a transmitter. The connecting sleeve is a ring structure with different diameters at both ends. The larger end is welded to the open end of the collecting body, and the smaller end is welded to the cable shell. All emitters use the same size and material of metal for neutron flux distribution measurement; or, each emitter uses the same or different size and material of metal for neutron energy spectrum measurement.

2. The integrated coaxial multi-layered annular emitter self-powered detector according to claim 1, characterized in that: The number of transmitters is four, including a first transmitter, a second transmitter, a third transmitter, and a fourth transmitter. The number of cable cores is four, including a first core wire, a second core wire, a third core wire, and a fourth core wire. The first core wire, the second core wire, the third core wire, and the fourth core wire are respectively connected to the inner walls of the first transmitter, the second transmitter, the third transmitter, and the fourth transmitter.

3. The integrated coaxial multi-layered annular emitter self-powered detector according to claim 1, characterized in that: The thickness of the closed end of the collector is 5-10mm, and the collector is made of Inconel600 material.

4. The integrated coaxial multi-layered annular emitter self-powered detector according to claim 1, characterized in that: The side insulation layer has a cylindrical structure, the bottom insulation layer has a disc-shaped structure, and the top insulation layer has a disc-shaped structure with a central through hole. The insulation layers are made of alumina material.

5. The integrated coaxial multi-layered annular emitter self-powered detector according to claim 1, characterized in that: The cable shell and cable core are both made of Inconel 600 material, and the cable insulation layer is made of aluminum oxide material.

6. The integrated coaxial multi-layered annular emitter self-powered detector according to claim 1, characterized in that: The connecting sleeve is made of Inconel 600 material.

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