阅读说明：本技术 堆芯快中子通量自给能探测器 (Reactor core fast neutron flux self-powered detector ) 是由 邵剑雄 刘渊哲 周殿伟 屈正 杨爱香 杨磊 李东仓 邱玺玉 陈熙萌 于 2020-12-28 设计创作，主要内容包括：本发明涉及一种堆芯快中子通量自给能探测器,包括：探头、连接套筒和传输电缆；连接套筒的一端连接探头,连接套筒的另一端连接传输电缆,且连接套筒与探头和传输电缆构成封闭结构；探头用于探测反应堆堆芯的快中子通量转化为电流信号,并将电流信号通过传输电缆传输至目标电子插件,以使目标电子插件根据电流信号确定反应堆堆芯快中子通量的大小,采用本申请的快中子通量自给能探测器,可以实现对快中子通量的测量,能够适应各种反应堆内的特殊环境,不仅仅结构简单,而且便于操作,使用寿命长。(The invention relates to a reactor core fast neutron flux self-powered detector, which comprises: the probe, the connecting sleeve and the transmission cable; one end of the connecting sleeve is connected with the probe, the other end of the connecting sleeve is connected with the transmission cable, and the connecting sleeve, the probe and the transmission cable form a closed structure; the probe is used for detecting the fast neutron flux of the reactor core and converting the fast neutron flux into a current signal, and the current signal is transmitted to the target electronic plug-in unit through the transmission cable, so that the target electronic plug-in unit determines the size of the fast neutron flux of the reactor core according to the current signal.)

1. A reactor core fast neutron flux self-powered detector, comprising: the probe, the connecting sleeve and the transmission cable;

one end of the connecting sleeve is connected with the probe, the other end of the connecting sleeve is connected with the transmission cable, and the connecting sleeve, the probe and the transmission cable form a closed structure;

the probe is used for detecting fast neutron flux of the reactor core and converting the fast neutron flux into a current signal, and transmitting the current signal to the target electronic plug-in unit through the transmission cable, so that the target electronic plug-in unit determines the fast neutron flux of the reactor core according to the current signal.

2. The in-core fast neutron flux self-powered detector of claim 1, wherein the probe comprises: a collector, an emitter and a first insulating layer;

the emitter is nested in the collector, and the first insulating layer is arranged between the collector and the emitter;

the collecting body is connected with the connecting sleeve, and the emitting body is connected with the transmission cable;

the emitter decays with fast neutrons passing through the collector and the first insulating layer to generate beta particles, the beta particles pass through the first insulating layer to be collected by the collector, so that a potential difference is formed between the collector and the emitter, the potential difference forms a current signal through the transmission cable to be transmitted to the target electronic plug-in unit, and the target electronic plug-in unit determines the magnitude of fast neutron flux of the reactor core according to the current signal.

3. The in-core fast neutron flux self-powered detector of claim 2, wherein the emitter is beryllium.

4. The in-core fast flux self-powered detector of claim 2, wherein the first insulating layer is magnesia powder or alumina powder.

5. The reactor core fast neutron flux self-powered detector of claim 2, wherein the collector is made of Inconel 600 material.

6. The in-core fast neutron flux self-powered detector of claim 1, wherein the transmission cable comprises a housing, a core and a second insulating layer;

the core wire is nested inside the shell, and the second insulating layer is arranged between the shell and the core wire.

7. The reactor core fast neutron flux self-powered detector of claim 6, wherein the housing is selected from Inconel 600 materials.

8. The reactor core fast neutron flux self-powered detector of claim 6, wherein the core wire is made of Inconel 600 material.

9. The in-core fast neutron flux self-powered detector of claim 6, wherein the second insulating layer is selected from magnesia powder or alumina powder.

10. The in-core fast neutron flux self-powered detector of any of claims 2 to 9, further comprising an ammeter;

the current meter is arranged between the collector and the transmission cable, and the collector, the emitter, the transmission cable and the current meter form a closed loop;

the current meter is used for measuring the magnitude of the current signal.

Technical Field

The invention belongs to the technical field of neutron flux detection, and particularly relates to a reactor core fast neutron flux self-powered detector.

Background

A self-powered detector is a new type of detector that began to develop in the 60's of the 20 th century. The emitter in the detector emits beta particles or secondary electrons under the action of neutrons or gamma photons, and the beta particles or the secondary electrons generate current in a loop after reaching the collector without an external power supply. With the development of nuclear reactor technology, self-powered detectors are widely used in core measurement systems. In large power reactors, core power distribution measurements must be made by a large number of reliable high temperature resistant self-powered neutron detectors that are resistant to high fluence and gamma fluence. The reactor core measuring system is an important instrument control system of the reactor and provides important guarantee for the safe operation of the reactor.

Neutron flux levels are an important detection aspect of core measurement systems, and the neutron energy spectrum in the core is mainly concentrated in fast neutron and thermal neutron energy regions. Neutron flux self-powered detectors using rhodium, vanadium, etc. as emitters have been developed, primarily for detecting core thermal neutron flux levels. For the high neutron flux level caused by the increase of the reactor power level and the increasingly severe reactor core temperature and gamma irradiation conditions, the performance of a general thermal neutron detector is rapidly deteriorated, even the general thermal neutron detector cannot be used. Fast breeder reactors with extremely poor reactor core conditions also require the use of special fast neutron detectors.

Therefore, a fast neutron self-powered detector is needed to detect the fast neutron flux level of the reactor core, and the neutron flux data of the reactor can be measured more comprehensively.

Disclosure of Invention

In order to solve at least the above problems in the prior art, the present invention provides a fast neutron flux self-powered detector for a reactor core, so as to realize the detection of fast neutron flux through a simple structure.

The technical scheme provided by the invention is as follows:

a core fast neutron flux self-powered detector, comprising: the probe, the connecting sleeve and the transmission cable;

one end of the connecting sleeve is connected with the probe, the other end of the connecting sleeve is connected with the transmission cable, and the connecting sleeve, the probe and the transmission cable form a closed structure;

the probe is used for detecting fast neutron flux of the reactor core and converting the fast neutron flux into a current signal, and transmitting the current signal to the target electronic plug-in unit through the transmission cable, so that the target electronic plug-in unit determines the fast neutron flux of the reactor core according to the current signal.

Optionally, the probe includes: a collector, an emitter and a first insulating layer;

the emitter is nested in the collector, and the first insulating layer is arranged between the collector and the emitter;

the collecting body is connected with the connecting sleeve, and the emitting body is connected with the transmission cable;

the emitter decays with fast neutrons passing through the collector and the first insulating layer to generate beta particles, the beta particles pass through the first insulating layer to be collected by the collector, so that a potential difference is formed between the collector and the emitter, the potential difference forms a current signal through the transmission cable to be transmitted to the target electronic plug-in unit, and the target electronic plug-in unit determines the magnitude of fast neutron flux of the reactor core according to the current signal.

Optionally, the emitter is made of beryllium.

Optionally, the first insulating layer is magnesium oxide powder or aluminum oxide powder.

Optionally, the collector is made of Inconel 600 material.

Optionally, the transmission cable includes a shell, a core and a second insulating layer;

the core wire is nested inside the shell, and the second insulating layer is arranged between the shell and the core wire.

Optionally, the shell is made of Inconel 600.

Optionally, the core wire is made of Inconel 600 material.

Optionally, the second insulating layer is made of magnesium oxide powder or aluminum oxide powder.

Optionally, the reactor core fast neutron flux self-powered detector further comprises a current meter;

the current meter is arranged between the collector and the transmission cable, and the collector, the emitter, the transmission cable and the current meter form a closed loop;

the current meter is used for measuring the magnitude of the current signal.

The invention has the beneficial effects that:

the invention provides a reactor core fast neutron flux self-powered detector, which comprises: the probe, the connecting sleeve and the transmission cable; one end of the connecting sleeve is connected with the probe, the other end of the connecting sleeve is connected with the transmission cable, and the connecting sleeve, the probe and the transmission cable form a closed structure; the probe is used for detecting the fast neutron flux of the reactor core and converting the fast neutron flux into a current signal, and the current signal is transmitted to the target electronic plug-in unit through the transmission cable, so that the target electronic plug-in unit determines the size of the fast neutron flux of the reactor core according to the current signal.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a fast-neutron flux self-powered detector in a reactor core provided by an embodiment of the invention;

FIG. 2 is a uranium-234 normalized fission neutron spectrum;

fig. 3 is a plot of the reaction cross-section of neutrons at different energies with each beryllium-9 reaction channel.

Reference numerals:

1. a collector; 2. a first insulating layer; 3. an emitter; 4. a housing; 5. a second insulating layer; 6. a core wire.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

Fig. 1 is a schematic structural diagram of a reactor core fast neutron flux self-powered detector provided by an embodiment of the invention, fig. 2 is a fission neutron energy spectrum normalized by uranium-234, and fig. 3 is a reaction cross section drawing of neutrons with different energies and beryllium-9 reaction channels.

As shown in fig. 1, the fast-neutron flux self-powered detector of the present embodiment includes: the fast neutron flux detection device comprises a probe, a connecting sleeve and a transmission cable, wherein one end of the connecting sleeve is connected with the probe, the other end of the connecting sleeve is connected with the transmission cable, the connecting sleeve, the probe and the transmission cable form a closed structure, the probe is used for detecting fast neutron flux of a reactor core and converting the fast neutron flux into a current signal, and the current signal is transmitted to a target electronic plug-in unit through the transmission cable, so that the target electronic plug-in unit determines the fast neutron flux of the reactor core according to the current signal.

In one particular implementation, the probe comprises: a collector 1, an emitter 3 and a first insulating layer 2; the emitter 3 is nested in the collector 1, and the first insulating layer 2 is arranged between the collector 1 and the emitter 3; the collecting body 1 is connected with the connecting sleeve, and the emitting body 3 is connected with the transmission cable; the emitter 3 reacts with fast neutrons penetrating through the collector 1 and the first insulating layer 2 to decay to generate beta particles, the beta particles penetrate through the first insulating layer 2 to be collected by the collector 1, so that a potential difference is formed between the collector 1 and the emitter 3, the potential difference forms a current signal through the transmission cable to be transmitted to the target electronic insert, and the target electronic insert determines the magnitude of fast neutron flux of the reactor core according to the current signal. The first insulating layer 2 is typically a magnesium oxide powder or an aluminum oxide powder, and the collector 1 is typically made of Inconel 600.

Specifically, the reactor core self-powered neutron detector has the principle that the probe emitter 3 generates nuclear reaction to generate radioactive isotopes under the bombardment of neutron beam current, the radioactive isotopes further generate beta-decay to emit electrons, the beta-particles are collected to form charge current in a loop, the current can be detected by an electronic instrument outside the reactor, and the neutron flux at the probe is further displayed. The material of the emitter 3 is therefore particularly important for a self-powered neutron detector of the reactor core, in this example beryllium-9 was chosen. Beryllium has only beryllium-9 which is a stable isotope in nature, so isotope separation is not needed, and the beryllium-9 is also a good electric conductor and has a melting point of 1278 ℃ to resist the high-temperature environment in the pile. The fast neutron source in the reactor core is fission neutron generated after fission of a fissile nuclide, fig. 2 is a fission neutron energy spectrum of uranium-234, and as can be seen from fig. 2, the energy of the fast neutron in the reactor core is almost below 10MeV, and because the neutron with the energy reaching 1MeV is called the fast neutron, the energy range of the neutron detected by the neutron detector with self-energy of the reactor core is 1MeV-10 MeV.

As shown in FIG. 3, the reaction section of each reaction channel for nuclear reaction of neutrons with different energies and beryllium-9 is plotted, wherein the reaction channel No. 1 isThe nuclear reaction of fast neutrons and beryllium-9 can generate radioactive isotope helium-6, and the helium-6 can further generate the radioactive isotope helium-6 with the half-life of 0.8sThe beta-decay gives off electrons, and the reaction cross section is small for the neutron energy region below 1MeV and can be basically ignored below 1 mb. For the fast neutron main energy area between 1MeV and 10MeV, the reaction has a suitably large neutron reaction cross section. The nuclear reaction has a maximum reaction cross-section of between about 100mb and 110mb when the fast neutron energy is around 2.5 MeV.

The No. 2 reaction channel is used for bombarding beryllium-9 with neutrons to generate composite nuclear beryllium-10. Beryllium-10 can decay to give off electrons, but the half-life is as long as 1.51 x 10⁶Such a long time response is not of practical interest as a detector.

Reaction channel No. 3 isBeryllium-8 will undergo an immediate alpha decay to become two alpha particles, and no electrons are finally generated in the reaction channel.

And the No. 4 reaction channel generates tritium particles to be emitted after the neutrons bombard the beryllium-9, and the No. 5 reaction channel generates deuterium particles to be emitted after the neutrons bombard the beryllium-9. The reaction cross sections of the two reaction channels are concentrated in a neutron energy region above 10MeV, and the energy of fast neutrons in the reactor hardly reaches above 10MeV as shown in the energy spectrum of FIG. 2, so that the two nuclear reactions hardly occur in the core.

So beryllium-9 is selected as the material of the emitter 3 special for the reactor core fast neutron self-powered detector probe, and the nuclear reaction is utilizedThereby collecting beta-particles formed by the decay of the helium-6 to form a detection current.

Specifically, transmission cable includes shell 4, heart yearn 6 and second insulating layer 5, and heart yearn 6 nests in the inside of shell 4, and second insulating layer 5 sets up between shell 4 and heart yearn 6, and shell 4 chooses for use Inconel 600 material, and Inconel 600 material is chosen for use to heart yearn 6, and second insulating layer 5 chooses for use for magnesium oxide powder or alumina powder. The alumina powder and the magnesia powder can maintain high resistance value and reduce current loss. The collector 1, the connecting sleeve and the housing 4 are filled with dense aluminum oxide powder or magnesium oxide powder, except for the emitter body 3 and the core wire 6.

Specifically, in order to facilitate direct reading of the real-time current value, an ammeter may be further provided; the ammeter is arranged between the collecting body 1 and the transmission cable, the collecting body 1, the emitting body 3, the transmission cable and the ammeter form a closed loop, and the ammeter is used for measuring the magnitude of current signals. After the probe receives fast neutron irradiation inside the reactor core, potential difference can be formed between the emitter 3 and the collector 1, the transmission cable transmits the potential difference to a loop of a subsequent electrical plug-in to form a current signal, a sensitive ammeter in the electrical plug-in can measure the magnitude of the current signal, and the magnitude of the current signal formed in the electrical plug-in is in direct proportion to the fast neutron flux at the probe, so that the reading of the sensitive ammeter can reflect the fast neutron flux at the probe inside the reactor core.

The invention uses metallic beryllium (Be) as the emitter 3 material, which utilizes the specific reaction channel between the neutron and the beryllium, and the nuclear reaction product can Be further decayed to generate beta particles. The neutrons in the fast neutron energy region have a reaction section higher than those in other energy regions, so that the beryllium can be used as an emitter 3 material special for fast neutron flux detection in a self-powered neutron detector of a reactor, and has the advantages of simple structure, good time response, low burnup rate and the like. The emitter 3 material of the probe part can react with fast neutrons to generate radioactive nuclide, the radioactive nuclide generates beta-decay to release electrons, the electrons escape from the emitter 3 to reach the collector 1, so that a potential difference is formed between the emitter 3 and the collector 1, a transmission cable transmits the potential difference to a subsequent electrical plug-in to form a current signal, and the fast neutron flux at the probe of the detector can be obtained by measuring the magnitude of the current signal by using a sensitive ammeter.

The reactor core fast neutron flux self-powered detector that this embodiment provided includes: the probe, the connecting sleeve and the transmission cable; one end of the connecting sleeve is connected with the probe, the other end of the connecting sleeve is connected with the transmission cable, and the connecting sleeve, the probe and the transmission cable form a closed structure; the probe is used for detecting fast neutron flux of a reactor core and converting the fast neutron flux into a current signal, and the current signal is transmitted to the target electronic plug-in unit through the transmission cable, so that the target electronic plug-in unit determines the fast neutron flux of the reactor core according to the current signal, the fast neutron flux self-powered detector can realize measurement of the fast neutron flux, and can adapt to special environments in various reactors, and the fast neutron flux self-powered detector is simple in structure, convenient to operate and long in service life, and the service life of the detector can reach more than 20 years due to the fact that the emitter 3 has low burnup rate.

The utility model provides a novel reactor core fast neutron self-energy-supply detector of fast neutron breeder still has following advantage:

1. the performance is reliable;

2. the accuracy is high;

3. long life in the reactor core;

4. the time response is short;

5. the dynamic range is wide;

6. the structure is firm;

7. the size is small;

8. the disturbance to neutron flux is small;

9. can work in the environment of high temperature and strong irradiation.

The main working flow of the reactor core fast neutron flux self-powered detector is roughly as follows:

in a first step, if the detector is placed somewhere inside the reactor core in operation, the fast neutron current passes through the probe section's shell 4 and the insulation, and undergoes a nuclear reaction with the emitter 3(Be)Residual nuclear helium-6 is produced.

In the second step, helium-6 subsequently decays with a half-life of 0.8s, giving off beta particles that decay to lithium-6. The shorter half-life ensures good time response of the detector.

In a third step, the negatively charged beta particles escape from emitter 3, pass through the insulating material and are collected by collector 1. The emitter 3 is thus positively charged and the collector 1 is negatively charged, so that a potential difference is formed between the emitter 3 and the collector 1.

And fourthly, forming current in a loop of the subsequent electrical plug-in unit by the potential difference formed by the probe part through the transmission cable, wherein the current magnitude has a direct proportion relation with the fast neutron flux at the probe. The fast neutron flux value at the probe inside the reactor core can be obtained from the current reading displayed by the sensitive current meter in the loop.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.

It should be noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.