CN219609232U - Radiation monitoring instrument - Google Patents

Abstract

The utility model discloses a radiation monitoring instrument. The radiation monitoring instrument is applied to radiation monitoring of a drain pipe of a steam generator, and comprises: lead shield and four detection modules; the four detection modules are symmetrically arranged on the outer side of the sewage pipeline of the steam generator; each detection module is arranged in the lead shielding body; the detection module is used for detecting the fluid radioactivity concentration in the drain pipeline of the steam generator. Therefore, the four detection modules are symmetrically arranged on the outer side of the drain pipe of the steam generator and are closely attached to the outer side of the drain pipe, so that the online and sensitive monitoring of the fluid radioactivity of the drain pipe of the steam generator can be realized, the problem that the online monitoring cannot be realized due to factors such as high temperature environment in the drain pipe of the steam generator in the prior art can be solved, and the sensitive monitoring of the main steam radioactivity can be indirectly realized.

Description

Radiation monitoring instrument

Technical Field

The utility model relates to the field of nuclear technology application, in particular to a radiation monitoring instrument.

Background

The steam generator of the pressurized water reactor nuclear power unit is a device connected with a first loop and a second loop, the heat transfer pipe of the steam generator accounts for about 80% of the pressure boundary of the first loop, once the heat transfer pipe is broken or leaked, the radioactive nuclide of the first loop enters the second loop, and nuclear steam has radioactivity. For a pure generator set, the normal operation working condition allows a certain leakage rate of the heat transfer pipe, and for the comprehensive utilization of nuclear energy of steam needing delivery, the steam supply pipeline needs to be isolated once the heat transfer pipe leaks. The two loops of the unit are provided with radioactive measuring instruments, but the measuring lower limit is too high for comprehensive utilization of nuclear energy, and particularly for nuclear steam needing delivery area boundaries, a sensitive and rapid radiation detector is needed. Therefore, on-line sensitive monitoring of the radioactivity of the two-circuit nuclear steam is an urgent technical problem to be solved.

Disclosure of Invention

The utility model provides a radiation monitoring instrument for realizing on-line monitoring of the concentration of the radioactivity of fluid in a blow-down pipe of a steam generator.

According to an aspect of the present utility model, there is provided a radiation monitoring instrument for use in radiation monitoring of a steam generator sewage drain, comprising: lead shield and four detection modules;

the four detection modules are symmetrically arranged on the outer side of the drain pipeline of the steam generator; and each detection module is arranged in the lead shielding body; the detection module is used for detecting the fluid radioactivity concentration in the drain pipeline of the steam generator.

Optionally, the radiation monitoring instrument further comprises: a thermal insulation module; the heat preservation module is closely attached to the outer wall of the sewage pipeline of the steam generator, and the four detection modules are arranged on the outer side of the heat preservation module.

Optionally, the heat preservation module is a nano-pore gel heat preservation layer.

Optionally, the detection module is a NaI (TI) crystal detector.

Optionally, the lead shield is a multi-layer stacked structure.

Optionally, the lead shield is integrally formed with the detection module.

Optionally, the minimum thickness of the lead shield is greater than 100mm.

Optionally, the lead shield is externally clamped by clamping means.

According to the technical scheme, the radiation monitoring instrument is applied to radiation monitoring of a drain pipe of a steam generator and comprises: lead shield and four detection modules; the four detection modules are symmetrically arranged on the outer side of the sewage pipeline of the steam generator; each detection module is arranged in the lead shielding body; the detection module is used for detecting the fluid radioactivity concentration in the drain pipeline of the steam generator. Therefore, the four detection modules are symmetrically arranged on the outer side of the drain pipe of the steam generator and are closely attached to the outer side of the drain pipe, so that the online monitoring of the radioactivity of the fluid in the drain pipe of the steam generator can be realized, and the problem that the drain pipe of the steam generator in the prior art cannot be monitored online due to factors such as high temperature environment can be solved.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the utility model or to delineate the scope of the utility model. Other features of the present utility model will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a radiation monitoring instrument according to an embodiment of the present utility model;

FIG. 2 is a schematic diagram of another radiation monitoring instrument provided in an embodiment of the present utility model;

fig. 3 is a schematic structural view of another radiation monitoring instrument provided in an embodiment of the present utility model.

Detailed Description

In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The nuclear energy is used as an energy source with high energy density, cleanness, high efficiency and stability, and from the viewpoint of energy efficiency, the direct use of heat energy is a more ideal mode, and the generation of electricity is only one mode of nuclear energy utilization. With the increasing number of nuclear power units in China and the continuous development of nuclear power application technology, the nuclear power non-electric application of the nuclear power units plays an important role in more and more fields under the 'double carbon' target pressure, and mainly utilizes the heat energy of nuclear steam to perform winter heating, industrial steam, sea water desalination, hydrogen production and the like.

The steam generator of the pressurized water reactor nuclear power unit is a device connected with a first loop and a second loop, the heat transfer pipe of the steam generator accounts for about 80% of the pressure boundary of the first loop, once the heat transfer pipe is broken or leaked, the radioactive nuclide of the first loop enters the second loop, and nuclear steam has radioactivity. The radioactive measuring instrument is arranged in the second loop of the unit, but the normal operation working condition of the unit allows a certain leakage rate of the heat transfer tube, the measurement lower limit of the unit is too high for comprehensive utilization of nuclear energy, and particularly, a sensitive and rapid radiation detector is needed for nuclear steam needing to be delivered from the factory. Therefore, on-line sensitive monitoring of the radioactivity of the two-circuit nuclear steam is a technical problem to be solved.

Under the condition that the heat transfer pipe of the steam generator is not leaked, other radionuclides except tritium in the secondary loop are equivalent to local natural radioactivity; after the heat transfer pipe of the heat transfer pipe leakage small steam generator leaks, the radionuclide of the first loop leaks into the second loop. The water in the two loops is evaporated to be steam, and in the process of converting the liquid phase into the vapor phase, the radionuclide has a certain distribution proportion in the vapor water, and in the conservative analysis, the vapor water distribution factor of iodine is considered to be 100, and the vapor water distribution factor of aerosol is considered to be 200. Therefore, the radioactivity concentration of the fluid in the drain pipe of the steam generator is 100 times that of the steam condensate, and the radioactivity concentration of the steam can be sensitively monitored by measuring the radioactivity of the drain pipe of the steam generator.

Because of the slow flow rate of the fluid in the drain of the steam generator, it is desirable to measure as close as possible to the steam generator in order to quickly measure the radioactivity of the steam for action. However, the temperature of the steam generator blowdown stream is at most 260 degrees celsius and the probe cannot be directly immersed in the fluid for measurement.

Therefore, the embodiment of the utility model provides a radiation monitoring instrument for realizing the online monitoring of the concentration of the radioactivity of the fluid in a drain pipe of a steam generator.

Fig. 1 is a schematic structural diagram of a radiation monitoring instrument according to an embodiment of the present utility model. Referring to fig. 1, a radiation monitoring instrument is applied to radiation monitoring of a drain pipe of a steam generator, the radiation monitoring instrument comprising: a lead shield 1 and four detection modules; the four detection modules are symmetrically arranged on the outer side of the drain pipeline 3 of the steam generator; and each detection module is arranged in the lead shielding body 1; the detection module is used for detecting the radioactivity concentration of the fluid in the sewage pipeline 3 of the steam generator.

Wherein each detection module is used for detecting radiation of the steam generator blow down pipe 3. The detection module may be a detector, and a specific type of detector may be set according to actual situations, which is not limited herein specifically.

As shown in fig. 1, the four detection modules are a first detection module 21, a second detection module 22, a third detection module 23 and a fourth detection module 24, which are symmetrically arranged outside the drain pipe 3 of the steam generator, each detection module is tightly attached to the outer part of the drain pipe 3, and each detection module is arranged in the lead shield 1. For example, the lower part of the first detection module 21 is tightly attached to the sewage drain pipe 3 and is arranged above the sewage drain pipe 3, both sides and the upper part of the first detection module 21 are all surrounded and arranged in the shielding body 1, namely, only one surface of the first detection module 21 facing the sewage drain pipe is free of a lead shielding body, thereby reducing the background, avoiding the monitoring of external radiation to the radiation in the pipeline, and improving the accuracy and the effectiveness of the radiation monitoring of the sewage drain pipe. Similarly, the left side part of the second detection module 22 is clung to the sewage pipeline 3 and is arranged on the right side of the sewage pipeline 3, and the upper side, the lower side and the right side of the second detection module 22 are all surrounded and arranged in the shielding body 1, namely, the second detection module 22 only has one surface facing the sewage pipeline and has no lead shielding body, so that the background can be reduced, the monitoring of external radiation to the radiation in the pipeline is avoided, and the accuracy and the effectiveness of the radiation monitoring of the sewage pipeline are improved. Similarly, the upper part of the third detection module 23 is tightly attached to the sewage drain pipe 3 and is arranged below the sewage drain pipe 3, both sides and the lower part of the third detection module 23 are all surrounded and arranged in the shielding body 1, namely, only one surface of the third detection module 23 facing the sewage drain pipe is free of a lead shielding body, so that the background can be reduced, the monitoring of external radiation to the radiation in the pipeline is avoided, and the accuracy and the effectiveness of the radiation monitoring of the sewage drain pipe are improved. Similarly, the right part of the fourth detection module 24 is clung to the sewage pipeline 3 and is arranged at the left side of the sewage pipeline 3, and the upper side, the lower side and the left side of the fourth detection module 24 are all surrounded and arranged in the shielding body 1, namely, only one surface of the fourth detection module 24 facing the sewage pipeline is provided with a lead shielding body, so that the background can be reduced, the monitoring of external radiation to the radiation in the pipeline is avoided, and the accuracy and the effectiveness of the radiation monitoring of the sewage pipeline are improved. Therefore, the four detection modules are symmetrically arranged on the outer side of the sewage pipeline 3, and the detection modules are uniformly distributed in the lead shielding body 1, so that the on-line monitoring of the fluid radiation in the sewage pipeline of the steam generator can be realized in a pipe side test mode, and the problem of on-line measurement of nuclear steam radionuclide of the pressurized water reactor is solved. In addition, each detection module has no lead shielding body facing the sewage drain pipe 3, and other surfaces are all surrounded and arranged in the lead shielding body, so that the influence of background radiation is greatly reduced by the formed structure, the performance of on-line monitoring is improved, and the accuracy and the effectiveness of the radiation monitoring of the sewage drain pipe are improved.

On the basis of the above embodiment, optionally, the detection module is a NaI (TI) crystal detector.

Wherein, the NaI (TI) crystal detector consists of NaI (TI) crystal and a photomultiplier. Wherein the photomultiplier tube has the function of amplifying the signal. The NaI (TI) crystal detector is a large-volume detector, can expand the detection range, and is beneficial to improving the detection performance of the whole instrument.

In addition, the detection module may also be other types of detectors, which may be specifically configured according to practical situations, and is not specifically limited herein.

Optionally, the lead shield is a multi-layer stacked structure.

The lead shield has a multilayer stack structure as shown in fig. 1.

Optionally, the lead shield is integrally constructed with the detection module.

The lead shielding body and the detection module are arranged into an integrated structure, so that the capability of resisting strong vibration or earthquake is improved, the monitoring instrument is protected, and the effectiveness of on-line monitoring of the monitoring instrument in a severe environment is guaranteed.

Optionally, the minimum thickness of the lead shield is greater than 100mm.

The specific thickness of the lead shield can be set according to practical situations, and is not specifically described herein.

Optionally, the lead shield is externally clamped by clamping means.

The lead shielding body and the detector form an integrated structure from the outside of the lead shielding body through the clamping device, the lead shielding body and the detector are connected with the support, and the support is rooted on the ground or a wall surface so as to resist earthquake with certain intensity, thereby ensuring that the monitoring instrument cannot damage the pipeline under the earthquake working condition. The fastening device can be formed by fastening saddle type metal sheets.

Fig. 2 is a schematic structural view of another radiation monitoring instrument provided in an embodiment of the present utility model. Optionally, referring to fig. 2, on the basis of the foregoing embodiment, the radiation monitoring instrument further includes: a thermal insulation module 4; the heat preservation module 4 is closely attached to the outer wall of the sewage pipeline 3 of the steam generator, and four detection modules are arranged on the outer side of the heat preservation module 4.

Because the interior of the drain pipeline of the steam generator is high-temperature fluid, in order to reduce the volume of the radiation monitoring instrument, the environment temperature of the detection module is ensured, and a heat preservation module is arranged between the detection module and the drain pipeline.

Wherein, the heat preservation module 4 is closely attached to the outer wall of the sewage pipeline 3 of the steam generator, and four detection modules are arranged outside the heat preservation module 4. As shown in fig. 2, the heat-insulating module 4 is arranged close to the outer wall of the drain pipe 3 of the steam generator, i.e. surrounds the outer side of the drain pipe by a circle. The lower part of the first detection module 21 is tightly attached to the heat preservation module 4 and is arranged above the heat preservation module 4, both sides and the upper part of the first detection module 21 are all arranged in the shielding body 1 in a surrounding way, namely, only one surface of the first detection module 21 facing the sewage drain pipe is free of a lead shielding body, so that the background can be reduced; and this kind of structural arrangement makes and remains certain clearance between first detection module 21 and lead shield 1 and the heat preservation module 4, on the one hand can prevent under the seismic operating mode that sewage pipes and detection module's influence each other, on the other hand, the air in the clearance can with external convection to play radiating effect. Similarly, the left side part of the second detection module 22 is clung to the heat preservation module 4 and is arranged on the right side of the heat preservation module 4, and the upper side, the lower side and the right side of the second detection module 22 are all arranged in the shielding body 1 in a surrounding way, namely, the surface of the second detection module 22, which faces the sewage drain pipe, is only free of a lead shielding body, so that the background can be reduced; and this kind of structural arrangement makes the second detection module 22 and lead shield 1 keep certain clearance with heat preservation module 4 between, on the one hand can prevent under the seismic operating mode the mutual influence of blow off pipeline and detection module, on the other hand, the air in the clearance can with external convection to play radiating effect. Similarly, the upper part of the third detection module 23 is tightly attached to the heat preservation module 4 and is arranged below the heat preservation module 4, both sides and the lower part of the third detection module 23 are arranged in the shielding body 1 in a surrounding way, namely, only one surface of the third detection module 23 facing the sewage drain pipe is free of a lead shielding body, so that the background can be reduced; and this kind of structural arrangement makes the third detection module 23 and lead shield 1 keep certain clearance with surrounding module 4 between, on the one hand can prevent under the seismic operating mode the mutual influence of blow off pipeline and detection module, on the other hand, the air in the clearance can with external convection to play radiating effect. Similarly, the right part of the fourth detection module 24 is clung to the heat preservation module 4 and is arranged at the left side of the heat preservation module 3, and the upper side, the lower side and the left side of the fourth detection module 24 are all arranged in the shielding body 1 in a surrounding way, namely, only one surface of the fourth detection module 24 facing the sewage pipeline is free of a lead shielding body, so that the background can be reduced; and this kind of structural arrangement makes the fourth detection module 24 and lead shield 1 keep certain clearance with surrounding module 4 between, on the one hand can prevent under the seismic operating mode the mutual influence of blow off pipeline and detection module, on the other hand, the air in the clearance can with external convection to play radiating effect.

Optionally, the heat-insulating module is a nano-pore gel heat-insulating layer.

The nano pore gel heat insulation layer has good heat insulation effect, and can reduce the size and weight of the radiation monitoring instrument as much as possible by adopting a high-performance heat insulation material, and has no influence on a nuclear grade pipeline.

In addition, other types of heat insulation structures or heat insulation materials can be selected, and the heat insulation structure or the heat insulation materials can be specifically arranged according to actual conditions, and are not particularly limited.

The thickness of the heat insulating layer may be set according to practical situations, and is not particularly limited herein.

Fig. 3 is a schematic structural view of another radiation monitoring instrument provided in an embodiment of the present utility model. In special cases, such as the reconstruction project after the installation of the sewage pipes, or the space limitation, the sewage pipes are relatively close to the wall surface, the arrangement structure shown in fig. 3 can be adopted, i.e. the surface of the sewage pipes, which is close to the wall 5, is not provided with a detector.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present utility model may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present utility model are achieved, and the present utility model is not limited herein.

The above embodiments do not limit the scope of the present utility model. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included in the scope of the present utility model.

Claims (8)

1. A radiation monitoring instrument for radiation monitoring of a drain pipe of a steam generator, comprising: lead shield and four detection modules;

the four detection modules are symmetrically arranged on the outer side of the drain pipeline of the steam generator; and each detection module is arranged in the lead shielding body; the detection module is used for detecting the fluid radioactivity concentration in the drain pipeline of the steam generator.

2. The radiation monitoring instrument of claim 1, further comprising: a thermal insulation module; the heat preservation module is closely attached to the outer wall of the sewage pipeline of the steam generator, and the four detection modules are arranged on the outer side of the heat preservation module.

3. The radiation monitoring instrument of claim 2, wherein the thermal insulation module is a nano-pore gel thermal insulation layer.

4. The radiation monitoring instrument of claim 1, wherein the detection module is a NaI (TI) crystal detector.

5. The radiation monitoring instrument of claim 1 wherein the lead shield is a multi-layer stack.

6. The radiation monitoring instrument of claim 1 wherein the lead shield is of unitary construction with the detection module.

7. The radiation monitoring meter of claim 1, wherein the minimum thickness of the lead shield is greater than 100mm.

8. The radiation monitoring instrument of claim 1, wherein the lead shield is externally mounted by a clamping device.