A method for reducing radioactivity intensity in field work sites

Abstract

The present invention belongs to the field of radioactive environmental protection, and specifically relates to a method for reducing the radioactive intensity of a field work site, comprising: step (1): determining the distribution characteristics of the radioactive field in the field work site; step (2): physically removing easily handled highly radioactive materials; step (3): using a coarse gravel layer to adsorb radon gas and block alpha particles; step (4): using a metal shielding blanket layer to block radon gas and beta rays; and step (5): using a fine-grained sand and gravel protective layer to block gamma rays. The method of the present invention effectively solves the problem of radioactive radiation protection in field work sites during the exploration or mining of radioactive mineral deposits.

Description

Technical Field

[0001] The invention belongs to the field of radioactive environmental protection, and in particular relates to a method for reducing the radioactive intensity of a field work site. Background Art

[0002] During radioactive mineral exploration activities, especially during the general survey and subsequent detailed investigation and exploration phases, including the later stages of mineral development, because ore deposits / mines are generally far from residential areas, work sites / residential camps (collectively referred to as field work sites) are established near the deposits / mines to minimize travel time, improve work efficiency, and facilitate water and electricity access. In many cases, due to the high radioactive background environment or the impact of radioactive ore, dust, and wastewater from mining activities, field work sites often have high levels of radioactivity, posing a health hazard to workers, especially those who reside there for extended periods of time.

[0003] The radioactive deposits currently explored or mined are mainly uranium deposits, in which the highest content of radioactive elements is 238 U, 238 The half-life of U is 4.468 billion years, and the radioactive damage it causes is not significant. 238 Starting from U, after 14 consecutive decays, a stable 206 Pb. Among these decay products, the most harmful is 222 Radon has a half-life of only 3.82 days. Radon gas and its daughters are the primary cause of uranium mine radioactive hazards, causing internal human exposure. Data indicate that the incidence of lung cancer caused by radon and its daughters is 3 to 30 times higher than the general population. The beta and gamma rays released during the decay of uranium and its daughters can also cause external radiation exposure. When uranium concentrations are too high, the gamma radiation can also cause harm to the human body.

[0004] The common approach to radiation protection in field workspaces is to ventilate and maintain good ventilation to promptly disperse and reduce radon concentrations in the air. Alternatively, workers should be equipped with radiation meters and leave the work environment before reaching the upper limit of the acceptable radiation dose. Both of these protection methods are considered end-of-line protection. For relatively fixed field worksites where workers spend extended periods of time or reside, front-end protection is more advantageous than end-of-line protection. However, radiation protection measures for permanent facilities such as nuclear power plants are extremely costly and unsuitable for temporary sites.

[0005] Therefore, it is particularly necessary to invent a simple protection method based on the front-end protection of the radioactive source and suitable for non-permanent field work sites. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for reducing the radioactive intensity of a field work site, thereby effectively solving the problem of radioactive radiation protection in a field work site during the exploration or mining of radioactive mineral deposits.

[0007] The technical solution for achieving the purpose of the present invention is as follows:

[0008] A method for reducing radioactivity intensity in a field work site, comprising the following steps:

[0009] Step (1): clarify the distribution characteristics of the radioactive field at the field work site;

[0010] Step (2): Physical removal of easily handled highly radioactive materials;

[0011] Step (3): The coarse gravel layer adsorbs radon gas and blocks alpha particles;

[0012] Step (4): a metal shielding blanket layer blocks radon gas and beta rays;

[0013] Step (5): The fine-grained sand and gravel protective layer blocks the gamma rays.

[0014] The step (1) specifically comprises: obtaining original measurement data by ground total gamma measurement, and performing Krag interpolation on the original measurement data and drawing a radioactivity intensity contour vector map using Suffer, Mapgis, and Arcgis mapping software.

[0015] The measurement accuracy of the total ground gamma measurement in step (1) is 1:500, the line spacing is 5m, and the point spacing is 1m. In the area where the radioactivity intensity suddenly changes, the measurement is encrypted. The encrypted measurement points can maximize the measurement accuracy.

[0016] The step (2) specifically comprises: gridding the radioactivity intensity contour vector diagram obtained by measuring in step (1), classifying all grids according to the radioactivity intensity, and dividing them into three groups: high, medium, and low; searching and clearing the grids classified as high and medium for artificial ground radioactive materials, and discarding the 5-10 cm soil layer on the surface of the grids with high overall radioactivity values caused by non-radioactive rolling stones.

[0017] The grid size in step (2) is 10m×10m.

[0018] The radioactivity intensity is classified into the following categories in step (2): when the uranium equivalent is greater than 100×10 -6 When the uranium equivalent is 30~100×10 -6 When the uranium equivalent is less than 30×10 -6 When the concentration of radioactivity is less than 1%, the radioactivity is classified as low.

[0019] The step (3) is specifically as follows: coarse gravel with low radioactive background is selected and laid on the ground after physical cleaning in step (2), with a laying thickness of 5 cm. After removing the mesh of the soil layer, the thickness is increased accordingly to keep the upper layer flat.

[0020] In the step (3), the gravel particle size is greater than 1 cm.

[0021] The step (4) specifically comprises: using a carpet containing a metal shielding layer, laying it flat on the upper layer of the coarse gravel layer, and splicing the carpet without gaps.

[0022] In the step (5), the protective layer is a fine-grained sand and gravel layer with a low radioactive background and a thickness of not less than 5 cm, and the sand and gravel particles are required to be less than 2 mm.

[0023] The beneficial technical effects of the present invention are:

[0024] 1. The present invention provides a method for reducing the radioactive intensity of a field work site, which realizes the front-end protection of natural radioactive sources and reduces the radiation protection cost of the field work site.

[0025] 2. The method provided by the present invention for reducing the radioactive intensity of a field workplace can effectively reduce the radioactive intensity of a field workplace and reduce radiation damage to the human body.

[0026] 3. The method provided by the present invention for reducing the radioactivity intensity in a field work site has the characteristics of simple process, low cost, short time consumption, and easy material acquisition, and is highly practical for temporary field work sites for radioactive mineral deposit exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a vertical section of the protective layer constructed by the method of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0029] The present invention provides a method for reducing the radioactivity intensity of a field work site, which specifically comprises the following steps:

[0030] Step (1): Clarify the distribution characteristics of the radioactive field at the field work site.

[0031] Conduct a radioactivity survey within the field work area to clarify the distribution characteristics of the radioactivity field within the site. The radioactivity survey method uses ground-based total gamma radiation measurements to obtain raw measurement data with a measurement accuracy of 1:500, a line spacing of 5 meters, and a point spacing of 1 meter. In areas with sudden changes in radioactivity intensity, intensified measurements are performed. Intensified measurement points maximize measurement accuracy. Using professional mapping software such as Suffer, MapGIS, and ArcGIS, the raw measurement data are interpolated using Krag interpolation and plotted as radioactivity intensity contour vectors to visualize the distribution characteristics of the site's radioactivity field.

[0032] Step (2): Physical removal of easily handled highly radioactive materials.

[0033] The radioactivity intensity contour vectors obtained in step (1) were gridded with a grid size of 10m×10m and numbered Nxy in grid order, where x is the xth grid from west to east and y is the yth grid from north to south. All grids were classified according to radioactivity intensity, and divided into high (uranium equivalent>100×10 -6 ), medium (uranium equivalent is 30~100×10 -6 ), low (uranium equivalent <30×10 -6 ) three groups. Grids categorized as high and medium were manually searched for and cleared of radioactive material on the ground. Grids with high overall radioactivity levels due to non-radioactive rockfall, for example, had 5-10 cm of soil removed from the surface. Grids categorized as low radioactivity levels remained intact.

[0034] Step (3): The coarse gravel layer adsorbs radon gas and blocks alpha particles.

[0035] Radon, a radioactive daughter of uranium, is the primary product causing radiation hazards. Radon is a radioactive inert gas that is easily released into the air and subsequently migrates. When implementing protection measures, in addition to blocking it as much as possible, it is also necessary to provide necessary crack spaces for its storage. Furthermore, a layer of pebbles of a certain thickness can block most alpha particles.

[0036] Use coarse gravel with low radioactive background, preferably gravel from basic rock, with a particle size greater than 1 cm. Sorting is not required. Lay it on the ground after physical cleaning in step (2) with a thickness of 5 cm. After removing the mesh of the soil layer, the thickness will be increased accordingly, keeping the upper layer flat. Figure 1 shown.

[0037] Step (4): The metal shielding blanket layer blocks radon gas and beta rays.

[0038] After step (3), the continuously generated radon gas will gradually accumulate in the gaps between the coarse gravel, which needs to be shielded. In addition, the beta rays produced during the decay of uranium, radon and its daughters are the main cause of external radiation and need to be blocked.

[0039] Physical barriers are highly effective against radon, alpha particles, and beta rays. A carpet with a metal shielding layer is laid flat on top of a coarse gravel layer. The carpet is seamlessly stitched to prevent radon leakage while also blocking alpha particles and beta rays.

[0040] Step (5): The fine-grained sand and gravel protective layer blocks the gamma rays.

[0041] After the protective treatments in steps (3) and (4), radioactive substances such as radon gas, alpha particles, and beta rays at the field work site have been largely blocked. However, it is still difficult to shield a small amount of gamma rays. The radioactivity intensity of radioactive sources at general field work sites is much lower than that of uranium deposits, and the radiation damage caused by gamma rays is relatively small. In addition, the metal shielding layer carpet in step (4) is easily damaged when subjected to external forces and loses its protective function. It is not suitable to be directly used as a work surface for stepping on, etc.

[0042] Therefore, a fine-grained sand and gravel layer with low radioactive background is laid on the top layer. The sand and gravel is required to be well sorted and generally have a particle size of less than 2mm. It serves as a protective layer for the metal-containing carpet layer to preserve its integrity and the effectiveness of radiation protection. At the same time, it blocks and reduces the intensity of radiation such as gamma rays. The thickness of the fine-grained sand and gravel layer is not less than 5cm. Figure 1 shown.

[0043] In summary, the method disclosed herein for reducing radioactivity in field work sites features a simple process, low cost, short processing time, and readily available materials. It is highly practical for temporary field work sites used in radioactive mineral deposit exploration. By implementing the above steps, radioactive substances such as radon gas, alpha particles, beta rays, and gamma rays can be effectively blocked, thereby reducing radioactivity in field work sites and minimizing radiation exposure to workers.

[0044] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Any content not described in detail in the present invention may be adapted from existing technologies.

Claims

1. A method for reducing radioactivity intensity in a field work site, characterized in that: The method comprises the following steps: Step (1): Determine the distribution characteristics of the radioactive field at the field work site; Step (2): Physical removal of easily handled highly radioactive materials; Step (3): The coarse gravel layer adsorbs radon gas and blocks alpha particles; Step (4): The metal shielding blanket layer blocks radon gas and beta rays; Step (5): The protective layer of fine-grained sand and gravel blocks the gamma rays; The step (1) specifically comprises: obtaining original measurement data by ground gamma total measurement, performing Krag interpolation on the original measurement data and drawing a radioactivity intensity contour vector map using Suffer, Mapgis, or Arcgis mapping software; The step (2) is specifically as follows: gridding the radioactivity intensity contour vector diagram obtained by the measurement in step (1), classifying all grids according to the radioactivity intensity into three groups: high, medium and low; searching and clearing the grids classified as high and medium for artificial ground radioactive materials, and discarding the 5 to 10 cm soil layer on the surface of the grids with high overall radioactivity values caused by non-radioactive rolling stones.

2. A method for reducing radioactivity intensity in a field work site according to claim 1, characterized in that: The measurement accuracy of the total ground gamma ray measurement in step (1) is 1:500, the line spacing is 5 m, and the point spacing is 1 m. In the area where the radioactivity intensity suddenly changes, the measurement is encrypted. The encrypted measurement points can maximize the measurement accuracy.

3. The method for reducing radioactivity intensity in a field work site according to claim 2, characterized in that: The grid size in step (2) is 10 m×10 m.

4. A method for reducing radioactivity intensity in a field work site according to claim 3, characterized in that: The radioactivity intensity is classified into the following categories in step (2): when the uranium equivalent is greater than 100×10 -6 When the uranium equivalent is 30~100×10 -6 When the uranium equivalent is less than 30×10 -6 When the concentration of radioactivity is less than 1%, the radioactivity is classified as low.

5. The method for reducing radioactivity intensity in a field work site according to claim 4, characterized in that: The step (3) is specifically as follows: coarse gravel with low radioactive background is selected and laid on the ground after physical cleaning in step (2), with a laying thickness of 5 cm. After removing the mesh of the soil layer, the thickness is increased accordingly to keep the upper layer flat.

6. The method for reducing radioactivity intensity in a field work site according to claim 5, characterized in that: In step (3), the gravel particle size is greater than 1 cm.

7. The method for reducing radioactivity intensity in a field work site according to claim 6, characterized in that: The step (4) specifically comprises: using a carpet containing a metal shielding layer, laying it flat on the upper layer of the coarse gravel layer, and splicing the carpet without gaps.

8. The method for reducing radioactivity intensity in a field work site according to claim 7, characterized in that: In step (5), the protective layer is a fine-grained sand and gravel layer with a low radioactive background and a thickness of not less than 5 cm, and the sand and gravel particles are required to be less than 2 mm.

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