RADIATION PROTECTION

A new generation of human radiation dose calculation technology based on deformable mesh-type phantom

ZHAO Ri, LIU Zhaoxing, LIU Na, WANG Xianxiang, ZHANG Jing, LIANG Runcheng, LIU Xin, LINGHU Renjing, DAI Yuling

RADIATION PROTECTION. 2023, 43(6): 533-541.

Abstract ( 39 )

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In order to improve the accuracy of dose calculation and meet the requirement of precise radiation protection, a complete method of dose calculation based on deformable mesh-type phantom was established, including the deformation algorithm of human mesh-type phantom and the high-speed Monte Carlo calculation method of this phantom. Algorithms of rigid rotation matrix, Laplacian volume map and As-rigid-as-possible transformance were used to deform the bone, soft tissue and internal organs respectively. The high speed Monte Carlo calculation of the phantom is based on Delaunay tetrahedralization technology. Based on this, a comparative test of dose calculation between the deformable mesh-type phantom and the non-deformable voxel phantom was carried out. The results show that, for squatting posture and bottom-up irradiating condition, the effective dose obtained by the mesh-type phantom is 51.2% higher and the organ dose is up to 98.6% higher than that obtained by the voxel phantom; for kneeling posture and antero-posterior irradiating condition, the effective dose obtained by the mesh-type phantom is 58.7% higher and the organ dose is up to 98.0% higher than that obtained by the voxel phantom. This paper focuses on breaking through the key techniques of the new generation of dose calculation technology, including the mesh-type phantom deforming algorithm and high speed Monte Carlo simulation method, which provides important support for the further development of high-precision dose calculation in China. In the future, it is expected to achieve accurate evaluation of personnel dose in precise radiation protection applications.

Study on the diamond dose measurement device for X-rays generated from ultrashort and ultra-intense laser facility

SONG Honghu, WU Zhen, QIU Rui, WEI Shuoyang, GONG Hui, ZHANG Hui, LI Junli

RADIATION PROTECTION. 2023, 43(6): 542-548.

Abstract ( 43 )

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An active dose measurement device based on a diamond detector was developed by our research group, and its performance was further studied. Monte Carlo software FLUKA was used to model the device. Energy and angular response simulations were performed based on the model. The device was calibrated in China National Institute of Metrology. Energy response and dose rate response calibration of the device was conducted by using ¹³⁷Cs and ⁶⁰Co. ¹³⁷Cs is used for the angular response calibration of the device. The results showed that the output current of the device was linear with the dose rate, and no obvious saturation phenomenon was observed. The device has a good angular response to ¹³⁷Cs, with the maximum variation less than 18%. Related verification experiments were carried out based on 3 MV and 6 MV electron pulse accelerator and “XG-III” laser facility. The results given by the device were consistent with Unidos dosimeter and TLD detectors, with maximum deviation less than 7% and 35%, respectively. Based on the above simulation and experiments, the feasibility of applying this device to real-time dose measurement of pulsed radiation field induced by ultra-short and ultra-intense laser facility is further verified, which provides an alternative for dosimetric method of such pulsed radiation field.

Development of a prototype instrument for α-surface contamination measurement based on air Radioluminescence

JIN Chenghe, ZHAO Yuan, WANG Yu, CAO Qinjian, XIONG Wanchun, HUANG Mingxiao, LIU Liye, LI Yan, DONG Jiajie, XIA Sanqiang

RADIATION PROTECTION. 2023, 43(6): 549-555.

Abstract ( 40 )

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Optical detection method of α surface contamination based on air Radioluminescence was one of the active area of research since its first demonstration at the beginning of this century. Compared to other kinds of α surface contamination measurement methods, the optical detection method of α surface contamination has the following advantages: it can realize non-contact α surface contamination measurement, it can effectively measure non-flat surface α contamination, and finally it can effectively reduce the risk of surface contamination. But on the other hand, affected by low emission yield of air Radioluminescence from α particle energy deposition, the detection limit of optical detection method of α surface contamination is too high compared with other kinds of α surface contamination methods. In this paper we presented a prototype instrument for measurement of α surface contamination. The instrument is based on optical detection of air Radioluminescence from α radiation, and work in telescope scanning mode. Primary performance testing results show that, the sensitivity of the prototype instrument is 2.63 s^-1/kBq, and the MDA is 1.0 kBq at 1 m distance from object lens and 10 s measurement time. Field experiment shows that the prototype instrument can also accurately measure space distribution of α surface contamination.

Design and research on pulsed X-ray reference radiation field

GAO Fei, ZHANG Xinyu, DING Yuyang, LIU Yuntao, WANG Feifei, CHEN Yizhen, LIU Jiarui, NI Ning, WANG Zilin, WANG Ziye, ZHAO Xu

RADIATION PROTECTION. 2023, 43(6): 556-565.

Abstract ( 28 )

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International research on radiation protection dosimetry mainly focuses on continuous radiation. However, pulsed radiation has been widely used in the fields of new detector development, industrial flaw detection, X-ray diagnosis, nuclear accident emergency and scientific research. Pulsed radiation dose (rate) measurement is very difficult. In order to solve the technical problem of pulse response test of active radiation dosimeter, the generation principle of pulsed X-ray and gamma ray radiation field is discussed, and the reference radiation field of pulsed X-ray is established based on a variety of X-ray machines. Combined with the secondary standard ionization chamber and pulse time measurement system, the research of pulsed radiation dose (rate) measurement technology is carried out. The experimental results show that the pulse width of the established pulsed X-ray reference radiation field can be adjusted between 25 ns to 10 s, and the instantaneous dose rate range is 5 mSv/h to 6.7×10⁵ Sv/h, which can be widely used to study the pulsed X-ray response characteristics of active radiation dosimeter. This work can be widely used to study the pulse response characteristics of active radiation dosimeter, which is of great significance to solve the calibration problem of pulsed radiation dose monitoring instrument.

Influence and correction of sample mass thickness variation for total alpha radioactivity measurement in water

DU Yunwu, DENG Xiaoqin, BI Chaowen, ZHU Jie, WANG Liang, ZENG Yi, GUO Xuying, WANG Yan, WANG Qian

RADIATION PROTECTION. 2023, 43(6): 566-575.

Abstract ( 39 )

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The detection efficiency of ²⁴¹Am and natural alpha radionuclide with different mass thickness was analyzed through experiments and Monte Carlo simulation. The relationship between mass thickness and detection efficiency, count rate, detection efficiency correction factor, as well as reciprocal detection efficiency were analyzed. And the relationship between detection efficiency, effective saturation thickness and energy were also analyzed. The results show that the detection efficiency of alpha radionuclide in water needs to be corrected by the detection efficiency correction factor, branch ratio and component ratio. When the mass thickness is 7 mg/cm², the equilibrium uranium detection efficiency correction factor is 0.96; With a mass thickness of 2 mg/cm², the equilibrium thorium detection efficiency correction factor is 1.01, and the equilibrium ²²⁶Ra-²²²Rn detection efficiency correction factor is 1.05. When the mass thickness is greater than 4 mg/cm², the detection efficiency correction factors of natural uranium, 4% enriched uranium and 97% enriched uranium are basically constant, which are 0.39, 039 and 0.47, respectively. When the mass thickness is less than 0.510 mg/cm², the detection efficiency correction factor of single alpha radionuclide radiation source is greater than 0.70. When the mass thickness is greater than the effective saturation thickness, the reciprocal of the detection efficiency is linear with the mass thickness. The effective saturation thickness is linearly related to the alpha ray energy.

Organic iodine formation, filtration emission, and steam environment simulation under core melt accident

GAO Linfeng, LIANG Junqin, YAO Yanyan, ZHAO Gaoxin, CHEN Xin, CHANG Sen, LI Xin

RADIATION PROTECTION. 2023, 43(6): 576-585.

Abstract ( 33 )

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When nuclear power plant coolant loss accident leads to core melting, radioactive iodine in nuclear fuel will be released into the containment with coolant and will form high temperature and high pressure steam environment. Under natural action and artificial intervention (spraying, etc.), the physical and chemical forms of iodine gradually change, forming a gaseous iodine environment dominated by organic iodine in the long-term stage. In this paper, the formation and filtration process of organic iodine in accident condition of nuclear power plant are described and the simulation of organic iodine vapor environment is carried out. By quantitative vaporization and multiple control, a wide-range of accurate simulation of organic iodine vapor environment represented by typical accident operating parameters (130 ℃, 399 kPa, 95%RH) was achieved. The simulation of iodine-containing steam environment can be used for the detection of organic iodine filtration performance of in-service adsorbents and the development of new adsorbents, which is of great significance in organic iodine filtration and controlled discharge under accident conditions at nuclear power plant.

The investigation and analysis of the associated radioactivity in a stone coal vanadium extraction enterprise in Gansu Province

WANG Fujun, WANG Haishan, HAO Jianguo, FANG Peng, MA Hongda, WEI Jinxiang, LIANG Xiaoye, DING Jingjie, LIU Zuoye

RADIATION PROTECTION. 2023, 43(6): 586-594.

Abstract ( 42 )

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In this paper, the geographical distribution of stone coal associated radioactive mineral resources in Gansu Province was introduced, and the natural radionuclides of stone coal associated minerals and radiation problem was studied in the process of development and utilization. Investigations found that the radioactivity of stone coal associated ore mainly comes from uranium series radionuclides ²³⁸U and ²²⁶Ra, and the average activity concentration of ²³⁸U and ²²⁶Ra in some mining areas exceeds 1 Bq/g. Taking a stone coal vanadium extraction enterprise in Gansu Province as an example, the radiation dose rate recieved by the staff and the public is evaluated, and the possibility of radioactive pollution transferring to the environment in the form of waste water, waste gas and radioactive solid waste is analyzed. In view of the existing radioactive pollution problems of stone coal associated radioactive mines, the corresponding suggestions are put forward.

Preliminary study on the method for estimating ¹⁸F activity through multi-time span spectral detection

FENG Jiangping, ZHANG Jinfan, GUO Jianfeng

RADIATION PROTECTION. 2023, 43(6): 595-597.

Abstract ( 24 )

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In order to solve the measurement difficulty of ¹⁸F activity, a new method (attenuation method) for measuring ¹⁸F activity with energy spectrum is put forward based on the decay law and binding energy spectrum multi-time span detection. Based on empirical calculations, the relative uncertainty of attenuation method is 3.1%. It is preliminarily believed that this method is correct and feasible, and can solve the technical difficulties in energy spectrum measurement of ¹⁸F.

Understanding and thinking about the role of collective dose concept in radiation protection management of nuclear power plants

WANG Chuan, HE Junnan, SHEN Enwei

RADIATION PROTECTION. 2023, 43(6): 598-602.

Abstract ( 30 )

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This paper compares the annual collective dose of the nuclear power units of China National Nuclear Power Co, Ltd (CNNP) with the WANO best quarter and median value from 2012 to 2021. This paper also analyzes the maximum annual individual dose, average annual individual dose and interval distribution of individual dose of CNNP’s NPPs, and compares the average annual collective dose per reactor unit among different reactor types worldwide. Based on the brief analysis of the main tasks of radiation protection during NPPs operation, this paper draws the following conclusions: Implementing the ALARA principle is not to pursue the low collective dose without limitation; the collective dose cannot be regarded as the only index to evaluate the performance of radiation protection management in NPPs; and the absolute value of collective dose cannot be simply equivalent to the standard of radiation protection management performance of NPPs. For the radiation protection management of NPPs, radiation dose control, radiation contamination control and radioactive materials control should be placed at the same important position, not one-sided emphasis on any aspect.

Simulation analysis of classical tracing test ETEX-1 with meteorological diffusion coupling model

GUO Huan, ZHANG Junfang, LI Mingye, HUANG Sha, ZHAO Duoxin

RADIATION PROTECTION. 2023, 43(6): 603-610.

Abstract ( 18 )

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The mesoscale meteorological model WRF and the diffusion model FLEXPART-WRF are coupled to numerically simulate the diffusion process of the classic European long-distance tracer test (ETEX-1). At the same time, the meteorological and diffusion simulation results are compared with the meteorological observation and concentration monitoring data collected respectively during the ETEX-1 test, in combination with the tracer test data and the statistical verification method in MVK (Model Validation Kit). The results show that the average correlation coefficient between the simulated and observed meteorological wind components is 0.43, and the average root mean square error is 3.4 m/s. The particle diffusion trend is highly matched with the wind field, and the near ground transit concentration covers most monitoring stations. The statistical results of indicators also show that the simulation and monitoring results are in good consistency, and the simulation results can effectively reflect the current flow field and diffusion characteristics. The meteorological diffusion coupling model can be used to assist in evaluating the impact of airborne radioactive pollutant diffusion on the environment under nuclear accidents.

Study on the influence of radon on the surrounding radiation environment of in-situ leaching uranium mine borehole area

WU Xuyang, SUN Juan, LIAN Guoxi, SONG Wangwang, AN Yifu, GAO Yang

RADIATION PROTECTION. 2023, 43(6): 611-619.

Abstract ( 26 )

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Radon is the main gaseous radioactive effluents released in the process of uranium mining and metallurgy, and radon release in in-situ leaching uranium mine borehole area mainly comes from the liquid extraction hole. The applicability of the traditional Gaussian model to such source terms is limited. Concentration distribution characteristics of radionuclide radon near ground surface in borehole area and its surroundings of a typical in-situ uranium leaching mine was studied by establishing CFD atmospheric diffusion mathematical model to couple solution under the actual terrain, radon source term and 2019 meteorological data, and the annual effective dose of the public was calculated by the annual average distribution mathematical model of individual dose. The results showed that terrain and wind speed had an important impact on radon diffusion in the drilling site, and wind speed played a dominant role. The higher the wind speed, the lower the radon concentration. Low and concave areas were easy to cause radon accumulation near emission sources, and local pollution was heavier. The distribution range of radon near the ground was mainly affected by the synergistic effect of wind speed and wind direction frequency, which grew as the latter increases. There was a positive correlation between radon concentration decay rate and diffusion distance. However, the radon emission concentration was at low level from liquid extraction hole, which had small contribution to the environmental radon concentration, impact on the surrounding environment and the public radiation, and the individual dose was not more than 0.001 1 mSv·a^-1. This study provides the theoretical supports for the layout of borehole area and the determination of the radiation safety distance.

Design optimization and effect analysis for radiation protection in Haiyang nuclear power plant

GOU Quanlu, WANG Caixia, ZHANG Jiannian, WAN Dengwei, YU Xiaodong, WANG Yilin

RADIATION PROTECTION. 2023, 43(6): 620-627.

Abstract ( 83 )

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Both units of Haiyang Nuclear Power Plant(NPP)Phase I have been equipped with AP1000 technology designed by Westinghouse of the United States. The radiation protection design was based on the priority of using advanced and mature technology. In order to reduce the radiation level of reactor unit and the occupational exposure dose to the staff, a lot of optimization design technology have been used: such as adopting the passive safety system to reduce the amount of equipment; integrated top head design of reactor pressure vessel; the maintenance-free main shield pump; steam generator primary circuit water chamber which adopted electrolytic polishing technology; spent fuel transport channel using of blocking water sac to improve equipment reliability; in order to reduce the maintenance workload. The main optimization measures adopted in the radiation protection design and the protection effect obtained by these measures were introduced, through comparison and analysis with typical data of domestic operating nuclear power plants. These measures can be used for reference for the optimization of radiation protection design in subsequent Phases of Haiyang NPP project, as well as for other peers.

Radiation protection design of nuclear air-cleaning units

GUO Chuangcheng, TANG Hui, QIU Jinmeng, WANG Chong, YANG Li, ZHANG Xin

RADIATION PROTECTION. 2023, 43(6): 628-633.

Abstract ( 32 )

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Based on the requirements of relevant standards at home and abroad and practical work experience, radiation protection factors to be considered in the design of nuclear air-cleaning units were synthesized, screened, and summarized. A design process control table that can be used by designer to enhance radiation protection considerations was developed. The table covers various aspects such as component selection, material selection, system configuration and location, maintainability, testability, operability, adsorbent cooling and fire protection, pressure and boundary leakage.

Development of high pressure water filter housing for CAP nuclear power unit

KONG Haixia, JING Xubing, LI Yuan, BIAN Xiangnan, QIAO Taifei, WANG Jia

RADIATION PROTECTION. 2023, 43(6): 634-641.

Abstract ( 19 )

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Radioactive water filter is an important equipment to ensure good water quality control and to reduce radiation dose in coolant circuit of Nuclear Power Unit. This paper developed a non-nuclear high pressure filter housing suitable for the third generation CAP Nuclear Power Unit, and the housing and its function components are designed in strict accordance with ASME BPVC-Ⅷ; finite element model of the housing is established by ANSYS 14.0 analysis software, and all the components fully meet the structural integrity and class II seismic requirements through the mechanical performance analysis under various load conditions; the manufactured housing has passed the hydrostatic test under about 1.25 times the design pressure, and there is no leakage and deformation at the weld, which can completely replace the imported products and break the foreign monopoly.

Directory and system of radiation environment supervision for exploitation and utilization of mineral resources

ZHENG Guofeng, LIAO Yunxuan, FENG Juen, ZHANG Ailing, SHANG Zhaorong

RADIATION PROTECTION. 2023, 43(6): 642-649.

Abstract ( 23 )

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This paper analyzed the process and consideration of determining the regulatory list of radiation environment for the exploitation and utilization of mineral resources. This paper also introduced the regulatory information system for the exploitation and utilization of mineral resources based on the current international and domestic requirements on the supervision of associated radioactive ore and the results of the second national survey of pollution sources. Suggestions for formulating classified regulatory requirements based on mineral types and technological processes were put forward. It is suggested to further deepen regulatory information system, add functions such as radiation environmental impact assessment, monitoring and early warning, and to promote modernization of regulatory capacity.

Suggestions on periodic safety assessment for near surface disposal facilities

WANG Chunli, WEI Fangxin, XU Chunyan, ZHANG Yu, ZHU Zhaowen, LEI Qiang

RADIATION PROTECTION. 2023, 43(6): 650-656.

Abstract ( 23 )

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At present, relevant requirements for periodic safety assessment for near surface disposal facilities are lack in China. The evaluation strategy, safety elements screening, evaluation points of the evaluation outline for the periodic safety assessment of near-surface disposal facilities were proposed in this paper, on the basis of investigation and analysis of relevant requirements and practices for periodic safety assessment of domestic and foreign nuclear facilities, taking into account the inherent characteristics and the requirements for the safety case of near-surface disposal facilities, with a view to providing references for the implementation of periodic safety assessment of near-surface disposal facilities and drafting relevant standards/guidelines in China.

Protective effects of extract from the root bark of Zanthoxylum piasezkii on radiation injury of human keratinocytes

WANG Chengfang, QI Xuesong, SHAO Shuai, DU Shushan, GOU Qiao

RADIATION PROTECTION. 2023, 43(6): 657-664.

Abstract ( 24 )

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Radiation-induced skin injury is a common complication of patients receiving radiotherapy. Its pathogenesis is complicated and varies greatly with individual patients. Therefore, it is necessary to develop the drugs for prevention and treatment of radiation-induced skin injury. Chinese prickly ash (Zanthoxylum bungeanum) is a common medicine used for skin diseases in traditional Chinese medicine. In this study, the radio-protective effect of the root bark extract of Zanthoxylum piasezkii (ZPE) on HaCaT was investigated and its mechanism was preliminary discussed. The results showed that 2 mg/mL ZPE could protect HaCaT cells from damage induced by 8.0 Gy γ ray irradiation, and could reduce apoptosis and necrosis of HaCaT cells. The mechanism may be related to the reduction of the secretion of IL-1β and IL-6, the level of ROS and the phosphorylation of p38 and JNK proteins. This work provides a theoretical basis for the development of preventive and therapeutic drugs for radiation-induced skin injury.

Review and analysis of radiation accidents in China from 2016 to 2020

GONG Yu, DANG Lei, LI Xiaoding, BAI Gang, QU Yunhuan, QI Yuan

RADIATION PROTECTION. 2023, 43(6): 665-670.

Abstract ( 46 )

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In order to draw lessons from the radiation accidents and to improve radiation safety level, the author summarizes and sorts out the radiation accidents that occurred in China from 2016 to 2020. The author also analyzes the types, levels and consequences of the accidents on the basis of the final evaluation of the 13th Five Year Plan for Nuclear Safety and Radioactive Pollution Prevention and Control and the 2025 Long-term Goals carried out by the Ministry of Ecology and Environment. The issues caused by radiation accidents are discussed. Suggestions are put forward, such as optimizing radiation safety supervision, cultivating nuclear safety culture, establishing radiation safety evaluation indicators, and improving the compensation mechanism for radiation accident damage.

Study of boron alkali curve in primary loop of nuclear power plant

YU Miao, GU Yu, ZENG Xiaomin, CHAI Qingzhu, WU Tong, WAN Weijin

RADIATION PROTECTION. 2023, 43(6): 671-677.

Abstract ( 23 )

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Boron alkali curve is an important control basis for water chemistry in the primary loop of nuclear power plant. Selecting a scientific and reasonable boron alkali curve is of great significance to reduce the deposition of corrosion products in the primary loop and the reduction of radioactive source terms. This paper first analyzes the purpose of primary loop water chemistry control, and analyzes the factors considered in the selection of primary loop pHT; secondly, this paper reviews the development history of boron alkali curves, focusing on the analysis of the characteristics of boron alkali curves of different reactor types in China; and finally, suggestions for the application of boron alkali curves in domestic nuclear power plants is put forward in this paper.

Research progress on the neurotoxicity of uranium and related functional mechanism

ZHANG Ting, ZHAN Jingming, ZHOU Xiaolin, ZHANG Hui, ZHANG Yanna

RADIATION PROTECTION. 2023, 43(6): 678-686.

Abstract ( 22 )

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With the continuous research on uranium, more and more toxicological evidence shows that uranium not only has some effects on the kidneys and bones, but also that uranium exposure may cause abnormal behavior of the nervous system such as depression, anxiety, movement and language disorders. The neurotoxicity of uranium is more insidious, but its long-term toxic effects can not be ignored. This paper introduces the neurotoxicity of uranium from the experimental study of animal models and population epidemiological investigation, and explains the mechanism of neurotoxicity of uranium from four ways, namely: inflammation and oxidative stress, apoptosis and necrosis, cell death or neuronal signal transduction and intracellular signal transduction, and Epigenetics mechanism of the central nervous system. This paper reviews the neurotoxicity and possible mechanisms of uranium (including depleted uranium), with the aim of providing new ideas for uranium toxicity research and better safeguarding the health of relevant practitioners.

A proposal to strengthen the application of nasal swab analysis in routine monitoring programme for internal contamination

WANG Yadong, WANG Lusheng, MA Yan, DAI Xiongxin

RADIATION PROTECTION. 2023, 43(6): 687-692.

Abstract ( 34 )

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In order to timely detect the occurrence of accidental internal radionuclide contamination of workers and accurately identify the contaminated individuals for medical treatment, it was proposed to strengthen the application of nasal swab analysis in the routine monitoring programme. The reliability of nasal swab analysis for internal contamination monitoring was validated by the human respiratory tract aerosol deposition model and the real data of nasal swab analysis from nuclear facilities in the United States and Japan. All the available methods of nasal swab analysis were listed and assessed in the aspects of speed and accuracy, and the prospect of imposing a daily nasal swab analysis for internal contamination monitoring was described. To make the proposal more practicable, several specific suggestions for further research were also put forward.

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