CN216979304U

CN216979304U - Radioactive iodine sampling and measuring device

Info

Publication number: CN216979304U
Application number: CN202220032932.4U
Authority: CN
Inventors: 周雪梅; 赖伟; 刘烨; 刘卫; 徐辉; 巢野
Original assignee: Shanghai Institute of Applied Physics of CAS
Current assignee: Shanghai Zhongke Xinhe Intelligent Technology Co.,Ltd.
Priority date: 2022-01-07
Filing date: 2022-01-07
Publication date: 2022-07-15
Anticipated expiration: 2032-01-07

Abstract

The utility model provides a radioactive iodine sampling and measuring device which comprises a detection assembly, a sampling assembly and a shielding shell, wherein the detection assembly is arranged in the shell; wherein, the detection subassembly includes: the device comprises a NaI detector, a multi-channel base and a detector shell; the sampling subassembly includes: the air inlet, the last room of surveying of being connected with the air inlet, the lower room of surveying that is located its below, arrange the indoor upper and lower baffle of surveying, and set up in the active carbon box of surveying the room below down, the probe and the active carbon box of NaI detector aim at in the vertical direction, the annular platelike structure of going up the baffle for radially inwards extending from the inner wall of last room of surveying, the baffle is for the circular platelike structure of horizontal extension is followed at the central authorities of last room of surveying down, form the narrow passageway that supplies gas to pass through between the upper and lower baffle in order to realize gaseous reposition of redundant personnel. According to the radioactive iodine sampling and measuring device, the structure is simple, the size is small, the sampling iodine is uniformly distributed in any section of the activated carbon box, and the air passage channel has good sealing performance.

Description

Radioactive iodine sampling and measuring device

Technical Field

The utility model relates to the technical field of radioactive iodine detection, in particular to a radioactive iodine sampling and measuring device.

Background

In reactor fission, radioactive iodine is one of its fission products, the fission yield is relatively high in nuclear accidents, and iodine, as an element that is very volatile, is easily leaked to the environment in the early stages of nuclear accidents. In nuclear medicine, radioactive iodine is also widely used in diagnosis and treatment of differentiated thyroid cancer and prostate cancer, and the radioactive iodine also has leakage risks in production, storage and use processes. The radioactive iodine carried in the environment is easy to be spread into human body through air, concentrated in thyroid gland and forms internal irradiation to the thyroid gland, thus posing great threat to human health. Therefore, radioactive iodine monitoring is one of the main bases for evaluating nuclear accident leakage and exposure dose to the public, and a radioactive iodine real-time sampling and measuring device is an important monitoring device in nuclear safety and radiation protection.

The radioactive iodine is collected by an activated carbon box, and the collected radioactive iodine has uneven distribution on any section of the activated carbon box and uneven distribution from the air inlet end to the air outlet end due to different air inlet modes. These all affect the accuracy of the calibration and measurement of the detection efficiency.

The patent with the application number of CN202011403651.7 and the name of 'a method for determining the activity and distribution of radioactive iodine-131 in an activated carbon filter box' introduces a method for obtaining the activity and distribution parameters of a sample to be measured by measuring the depth-efficiency function of the activated carbon filter box and solving an transcendental equation after measuring the positive direction and the negative direction of the sample to be measured. The measuring method is based on the premise that the distribution of the activated carbon filter box on any section is relatively uniform, but the patent does not give a method for improving the distribution uniformity of any section.

The patent with the application number of CN202023112479.8 and the name of a radioactive iodine detection device introduces a radioactive iodine detection device with an invaginated air chamber at the matching position of the detection end of a NaI detector, and the detection end of the NaI detector extends into a shielding detection chamber to be matched with an activated carbon iodine box up and down in a facing way to detect the radioactive iodine adsorbed in the activated carbon iodine box. However, the layout design of the air chamber, the air cavity and the detection cavity increases the shielding volume and increases the size and weight of the detection device.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a radioactive iodine sampling and measuring device, so that the problems of inaccurate measurement and overlarge device volume and weight caused by uneven distribution of iodine on any section of an activated carbon box in the prior art are solved.

In order to solve the technical problems, the utility model adopts the following technical scheme:

the radioactive iodine sampling and measuring device comprises a detection assembly, a sampling assembly and a shielding shell; wherein the detection assembly comprises: the device comprises a NaI detector with a photomultiplier, a multi-channel base with an amplification module and a detector shell; the sampling assembly includes: set up in the air inlet in the shielded enclosure outside, with last detection room that the air inlet is connected is located go up the lower detection room of detection room below, arrange in go up the indoor overhead gage of detection and lower baffle, and set up in detect the activated carbon box of room below down, the probe terminal surface of NaI detector with activated carbon box up end aligns in the axial, wherein, the overhead gage be for certainly the annular platelike structure of the radial inward extension of inner wall of detection room, the baffle is down the central authorities of going up the detection room follow the circular platelike structure of horizontal extension, the overhead gage with form the reposition of redundant personnel of the narrow passageway that supplies gas to pass through in order to realize gas down between the baffle.

According to a preferred embodiment of the present invention, the lower baffle has a first working surface extending horizontally and a second working surface extending obliquely downward from an edge of the first working surface, and the upper baffle has a third working surface extending parallel to the first working surface and a fourth working surface extending parallel to the second working surface.

Preferably, the lower baffle plate has a trapezoidal cross-sectional shape, and the included angle of the second working surface of the lower baffle plate relative to the horizontal plane is 40-50 degrees.

Preferably, the upper detection chamber has a cylindrical cavity structure, and the lower detection chamber has a tapered cavity structure with a large upper part and a small lower part.

Preferably, the inner wall of the lower detection chamber is polished.

Preferably, the top end of the upper detection chamber is provided with a sealing baffle plate for protecting a probe of the NaI detector.

The activated carbon box is located in the activated carbon box support holder, and a double-layer sealing ring is arranged in the activated carbon box support holder to ensure the sealing performance of the gas path pipeline.

And a filter element with a metal wire screen is arranged at the air inlet to filter large-particle-size particles in the air.

The shielding shell is composed of a lead shielding layer and a container shell, the probe of the NaI detector and the activated carbon box are provided with the thicker lead shielding layer, and the rear end of the NaI detector is provided with the thinner lead shielding layer.

The lower end surface of the activated carbon box is connected with a conical air outlet, the air outlet is connected with a pipeline, and the rear end of the pipeline is connected with a pressure gauge, a flow controller and an air pump.

Compared with the prior art, the radioactive iodine sampling and measuring device provided by the utility model has the following advantages:

1) by additionally arranging the specially designed upper baffle and lower baffle in the upper detection chamber and utilizing a narrow passage formed between the upper baffle and the lower baffle, the uniform distribution of fluid at the inlet of the activated carbon box is realized, the uniformity of distribution of radioactive iodine in any section of the activated carbon box is ensured, the accuracy of detection efficiency measurement and calibration is improved, and the detection accuracy can be improved by more than 3%;

2) the top end of the detection chamber adopts a sealing baffle plate, so that the possibility of air leakage at the detector is eliminated, the tightness of an air passage is ensured, and a probe of the detector is protected;

3) through the reasonable design of the lead shielding layer, the influence of gamma rays in the background on the measurement is effectively removed, the detection lower limit is reduced, the detection lower limit is related to the design of a detector probe, the lead shielding and the like, and the device is more portable when the same detection lower limit is reached; the lower detection limit of the device can be lower when lead shielding with the same weight is adopted.

In conclusion, the radioactive iodine sampling and measuring device provided by the utility model has the advantages of novel and reasonable design, simple structure, small volume, good air channel sealing performance, capability of protecting the probe, more importantly, uniform distribution (the non-uniformity of the distribution is less than or equal to 0.3%) of the sampling iodine in any section of the activated carbon box, capability of improving the measurement accuracy, reduction of the detection lower limit and wider application range.

Drawings

Fig. 1 is a schematic view of the overall structure of a radioactive iodine sampling and measuring apparatus provided according to the present invention;

FIG. 2 is an enlarged schematic view of a portion of the radioactive iodine sampling and measuring apparatus shown in FIG. 1;

FIG. 3 is a schematic connection diagram showing a partial structure of a radioactive iodine sampling and measuring apparatus;

wherein the reference numerals have the following meanings:

1. a NaI detector; 2. a plurality of bases; 3. a detector housing; 4. sealing the baffle; 5. fixing the clamping groove; 6. an air inlet; 7. an upper detection chamber; 8. a lower detection chamber; 9. an upper baffle plate; 10. a lower baffle plate; 10a, a first work surface; 10b, a second working surface; 9a, a third working surface; 9b, a fourth working surface; 11. an activated carbon cartridge; 12. the activated carbon box support bracket; 13. a supporting and supporting elastic component; 14. an air outlet; 15. a lead shielding layer; 16. a container housing; 17. a container holder; 19. a pressure gauge; 20. a flow controller; 21. an air pump; 100. a radioactive iodine sampling and measuring device; 101. a detection component; 102. a sampling assembly; 103. a shielding housing.

Detailed Description

The present invention is further illustrated by the following examples. It is to be understood that the following examples are illustrative of the present invention only and are not intended to limit the scope of the present invention.

As shown in fig. 1, there is a radioactive iodine sampling and measuring apparatus 100 according to a preferred embodiment of the present invention, which mainly includes: a probe assembly 101, a sampling assembly 102, and a shielded housing 103.

Wherein, detecting component 101 includes: the detector comprises a NaI detector 1 with a photomultiplier, a multi-channel base 2 with an amplification module and a detector shell 3. The NaI detector 1 is placed in a fixed clamping groove 5 in a detector shell base with a positioning hole. And the signal and power socket of the multi-channel base 2 are connected with an industrial personal computer, and detection information is displayed through an external industrial personal computer interface.

Referring to fig. 1 and 2, the sampling assembly 102 includes: the detection device comprises an air inlet 6 arranged on the outer side of a shielding shell 103, an upper detection chamber 7 connected with the air inlet 6, a sealing baffle 4 arranged at the top end of the upper detection chamber 7, a lower detection chamber 8 positioned below the upper detection chamber 7, an upper baffle 9 and a lower baffle 10 arranged in the upper detection chamber 7, an activated carbon box 11 arranged below the lower detection chamber 8, and the probe end surface of a NaI detector 1 is axially aligned with the upper end surface of the activated carbon box 11.

Wherein, the position about 1mm under seal baffle 4 is located NaI detector 1's the probe, can protect NaI detector 1's probe to this seal baffle 4 has sealed design, makes gaseous under the negative pressure effect, only can follow in 6 entering detection rooms of air inlet. The fixed clamping groove 5 is connected with the sealing baffle 4 through a fixed pin.

As shown in fig. 2, the upper baffle 9 is an annular plate-like structure extending radially inward from the inner wall of the upper detection chamber 7, the lower baffle 10 is a circular plate-like structure extending horizontally in the middle of the upper detection chamber 7, and according to the preferred embodiment, the lower baffle 10 has a first working surface 10a extending horizontally and a second working surface 10b extending obliquely downward from the edge of the first working surface, the upper baffle 9 has a third working surface 9a extending parallel to the first working surface 10a, and a fourth working surface 9b extending parallel to the second working surface 10b, whereby a narrow passage for gas to pass is formed between the upper baffle 9 and the lower baffle 10 to achieve gas diversion so that gas can uniformly enter the activated carbon cartridge 11. It should be understood that the inventors finally determined such a model by simulating different models using the fluid analysis software Fluent in ansys and calculating the uniformity of the distribution of the fluid at the inlet of the activated carbon cartridge.

According to a preferred embodiment of the utility model, the upper baffle 9 has an internal diameter of 20mm to 30mm and a height of 2mm to 4mm, preferably 3 mm. The cross section of the lower baffle 10 is a regular trapezoid, and the trapezoid angle is preferably 40 to 50 degrees, and preferably 45 degrees.

The activated carbon box 11 is arranged in the activated carbon box support 12, a double-layer sealing ring is arranged in the support 12 to ensure the sealing performance of the gas path pipeline, the activated carbon support 12 is connected with the support elastic component 13, and the activated carbon box can be replaced by moving the support elastic component 13.

O-shaped sealing rings are arranged at the joints of the air inlet 6, the air outlet 14 and the sealed container. The air inlet 6 is also provided with a filter element with a metal wire screen to filter large-particle-size particles in the air, reduce interference on measurement and prolong the service time of the activated carbon box.

The shielding shell 103 mainly comprises a lead shielding layer 15 and a container shell 16, and the thickness of the lead shielding layer 15 is selected according to the gamma ray energy to be shielded and the detection lower limit. Because the environment gamma background mainly affects the activated carbon box 11 and the detector probe, a thicker lead shielding layer is adopted at the probe and the activated carbon box, a thinner lead layer is adopted at the rear end 2 of the detector, for example, a lead layer of 1cm can be adopted at the rear end 2 of the detector, a thicker lead shielding layer of 2cm or thicker is adopted at the probe and the activated carbon box, the lead shielding layer is selected according to the detection lower limit, or the lead layer is removed according to the condition, so that the weight of the detection device is reduced, the adoption of a movable monitor is facilitated, the larger the size of the detector component is, the more the weight can be reduced, and the monitor can be reduced by at least 10 kg.

The entire apparatus is supported by the container support 17.

As shown in fig. 3, the radioactive iodine sampling and measuring apparatus 100 further includes a pressure gauge 19 connected to the pipe of the air outlet 14, a flow controller 20, and a suction pump 21. The activated carbon cartridge can be monitored for replacement by the pressure gauge 19, and the volume of the sampled fluid can be accurately measured by the flow controller 20. The air is pumped by the air pump 21, negative pressure is formed in the air flow channel, so that the fluid carrying the radioactive iodine passes through the filter element at the air inlet 6 under the action of the negative pressure, particles in the fluid are removed by the filter device, and the radioactive iodine is adsorbed in the activated carbon box.

In order to effectively and accurately measure the radioactive iodine, the inventor also provides a use range and an optimization recommendation for parameters such as flow rate, pressure and the like: the flow range is 10-50L/min, the recommended value is 35L/min, the matched flow controller 20 is adjustable, and the range is 0-60L/min; the pressure drop range is 10 kPa-35 kPa, the recommended value is 20kPa, and the range of a matched pressure gauge 19 is-100 kPa-0 kPa; the idling flow rate of the suction pump 21 is preferably 100L/min.

According to the radioactive iodine sampling and measuring device provided by the utility model, a radioactive iodine sampling and measuring method is further provided, and the specific steps are as follows:

under the action of the negative pressure of the air suction pump 21, fluid carrying radioactive iodine enters from the air inlet 6 with the filter element, then enters the upper detection chamber 7, passes through a gas flow channel formed by the upper baffle plate 9 and the lower baffle plate 10, reaches the lower detection chamber 8, then is uniformly guided to reach the upper end face of the activated carbon box 11, the radioactive iodine in the fluid is adsorbed in the activated carbon box 11, the NaI detector 1 detects gamma particles emitted by the radioactive iodine, so that the monitoring of the radioactive iodine in the environment is realized, the gas after the radioactive iodine is removed flows out from the air outlet 14, and the pressure gauge 19 and the flow controller 20 connected with a pipeline at the air outlet are used for accurately monitoring the fluid pressure and the sampling volume.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The utility model has not been described in detail in order to avoid obscuring the utility model.

Claims

1. The radioactive iodine sampling and measuring device is characterized by comprising a detection assembly, a sampling assembly and a shielding shell; wherein the detection assembly comprises: the device comprises a NaI detector with a photomultiplier, a multi-channel base with an amplification module and a detector shell; the sampling assembly includes: the utility model provides a gas detection device, including shielding shell, NaI detector, active carbon box, baffle, circular platelike structure, set up in the air inlet in the shielding shell outside, with last detection chamber that the air inlet is connected is located go up the lower detection chamber of detecting the room below, arrange in go up the overhead gage and lower baffle in detecting the indoor, and set up in detect the active carbon box of room below down, the probe terminal surface of NaI detector with the active carbon box up end is aimed at in the axial, wherein, the overhead gage be for certainly go up the annular platelike structure of detecting the radial inside extension of indoor inner wall, the baffle is down the central authorities of going up the detection chamber follow the circular platelike structure of horizontal extension, the overhead gage with form the narrow passageway that supplies gas to pass through between the baffle down in order to realize gaseous reposition of redundant personnel.

2. The radioactive iodine sampling measurement apparatus of claim 1, wherein said lower baffle has a first working surface extending horizontally and a second working surface extending obliquely downward from an edge of said first working surface, and said upper baffle has a third working surface extending parallel to said first working surface and a fourth working surface extending parallel to said second working surface.

3. The radioiodine sampling measurement device of claim 2, wherein the lower baffle plate has a trapezoidal cross-sectional shape, and the second working surface of the lower baffle plate is angled 40-50 ° relative to a horizontal plane.

4. The radioiodine sampling measurement device of claim 1, wherein the upper detection chamber has a cylindrical cavity configuration and the lower detection chamber has a frusto-conical cavity configuration with a large top and a small bottom.

5. The radioiodine sampling measurement device of claim 1, wherein the lower detector chamber inner wall is polished.

6. The radioactive iodine sampling and measuring device of claim 1, wherein the top end of the upper detection chamber is provided with a sealing baffle plate for protecting the probe of the NaI detector and ensuring the airtightness of sampling and measuring.

7. The radioactive iodine sampling and measuring device of claim 1, wherein the activated carbon box is located in an activated carbon box support holder, and a double-layer sealing ring is arranged in the activated carbon box support holder to ensure the tightness of the gas path pipeline.

8. The radioiodine sampling measurement device of claim 1, wherein a filter element with a wire mesh screen is provided at the air inlet to filter large particle size particles in the gas.

9. The radioactive iodine sampling and measuring device of claim 1, wherein the shielding shell is composed of a lead shielding layer and a container shell, a thicker lead shielding layer is adopted at a probe and an activated carbon box of the NaI detector, and a thinner lead shielding layer is adopted at the rear end of the NaI detector.

10. The radioactive iodine sampling and measuring device of claim 1, wherein the lower end face of the activated carbon box is connected with a conical air outlet, the air outlet is connected with a pipeline, and the rear end of the pipeline is connected with a pressure gauge, a flow controller and a suction pump.