RADIATION PROTECTION

Introduction and review on the status of protection system against radon exposure

GUO Qiuju, ZHANG Lei

RADIATION PROTECTION. 2022, 42(3): 177-183.

Abstract ( 135 )

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The World Health Organization (WHO) published “Handbook on Indoor Radon: A Public Health Perspective” in 2009 after its review on epidemiological studies of lung cancer and radon exposure. WHO concluded that most radon-induced lung cancers occur from low and medium dose exposures in residents’ home. Radon is the second cause of lung cancer after smoking, and a relative higher risk is showing. After that, International Committee on Radiological Protection (ICRP) published several publications related to the protection against radon exposure. Great changes on reference level of indoor radon concentration, protection strategy and dose conversion factor were recommended. This paper introduces these changes and their related background, focusing on dose conversion factor. The viewpoint of UNSCRAR and IAEA are also introduced and discussed.

Development of single-cell single-particle microbeam and applications in radiobology

CHEN Faguo, LIN Haipeng, WANG Yong, DANG Xuhong, LIANG Runcheng, REN Yue

RADIATION PROTECTION. 2022, 42(3): 184-192.

Abstract ( 113 )

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The latest development of single-cell single-particle microbeam and its applications in radiobiology are reviewed. Particle beam from accelerator can be collimated or be focused into micrometer or sub-micrometer size in the air. Focused microbeam has become the mainstream of development due to its higher spatial resolution and faster electromagnetic scanning irradiation throughput. Coupling with advanced fluorescence microscopy and time-lapse imaging, the current microbeam can visualize the early response of living cell to radiation induced DNA damage online. Based on the characteristics of targeted irradiation individual cell or subcellular compartment with precise controlled particle number, microbeam has become a unique experimental research tool for low dose effect, radiation induced bystander effect and radiation sensitivity of subcellular compartment. Its applications are gradually expanding from cell culture model to more complex tissue or in vivo system in order to investigate the spatial and temporal evolution of radiation response of irradiated biological samples.

Research on radiation dose field reconstruction method based on monitoring data from Fukushima nuclear accident

XU Yao, CHEN Xiaolei, HUANG Guangwei, WU Yunhui, CHEN Lin

RADIATION PROTECTION. 2022, 42(3): 193-200.

Abstract ( 154 )

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The reconstruction of radiation dose field is an important tool for emergency work after nuclear accidents. In order to explore suitable interpolation method for radiation dose field reconstruction, in this article the inverse distance weighted interpolation, kriging interpolation, linear triangulation interpolation, and radial basis function interpolation are used respectively, to interpolate and reconstruct the radiation monitoring data released after the accident at the Fukushima Daiichi Nuclear Power Plant in Japan. By dividing different numbers of test sets, the accuracy of radiation dose field reconstruction through these interpolation methods were compared when taking the root mean square error, average absolute error, and standard deviation as basis. The research results show that the radial basis function interpolation is superior to the other three methods in accuracy of interpolation, and can determine the radiation dose distribution more accurately. It is also expected to be applied to other radiation dose fields and provide powerful dose assessment and radiation dose field reconstruction tools for subsequent nuclear emergency work.

Rapid determination of lead-210 in soil sample using solid phase extraction and liquid scintillation counting method

JIANG Dong, FANG Chunming, LU Di, DU Yaofang, WANG Haitao, ZHAO Yuling, SHANG Di

RADIATION PROTECTION. 2022, 42(3): 201-207.

Abstract ( 91 )

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A rapid analysis method of Lead-210 in soil sample was established by using solid phase extraction and liquid scintillation counting method. The lead in soil sample was enriched by concentrated nitric acid heating extraction method. The lead specific resin was used as an adsorbent, and citric acid solution was used for desorption. The chemical recovery rate of lead was measured by ICP-AES and the activity concentration of Lead-210 was measured by liquid scintillation spectrometer. When the amount of soil sample was 1.0 g and the measuring time was 60 minutes, the minimum detectable concentration of this method was 24.8 Bq/kg and the precision of this method was 4.8%, and the recovery rate of this method was 100.1%-102.6%, which met the requirement of Lead-210 analysis in soil sample.

Maintenance experience for steam generator leak rate monitor

ZHANG Zhenyu, WU Pin, LUO Peng, WANG Haojun, XU Hu

RADIATION PROTECTION. 2022, 42(3): 208-213.

Abstract ( 135 )

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Radiation monitor is used in PWR nuclear power plant to monitor the concentration of N-16 radionuclide in the main steam pipe, and then to calculate the damage rate of steam generator. Because the steam generator leakage monitor works in high temperature and humidity environment for a long time, the failure rate of the monitor is high, which may affect the normal operation of the nuclear power plant. In this paper, the fault diagnosis, fault cause analysis and repair technology research of six SGLM201 steam generator leakage rate monitors are completed, and the technical maintenance scheme and the whole machine damp heat protection and reinforcement technical scheme are put forward for each fault. After repair, the monitor is verified by environmental test and calibration test, which proves that the technical maintenance scheme proposed in this paper is feasible, which can effectively reduce the failure rate of the equipment and improve its long-term operation reliability.

Experience on environmental protection acceptance monitoring and evaluation from Haiyang NPP

HAN Tao, WANG Fang, ZUO Weiwei, HUANG Yanjun

RADIATION PROTECTION. 2022, 42(3): 214-221.

Abstract ( 158 )

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According to the requirements of relevant regulations and standards in China, an environmental protection acceptance monitoring plan for NPP completion was proposed in view of the design characteristics of AP1000 at Haiyang Nuclear Power Plant. The environmental protection acceptance monitoring results were presented and evaluated, from which the conclusion of acceptance was made. Moreover, the experience on environmental protection acceptance monitoring and evaluation for nuclear power plant (NPP) was summarized in the aspect of the consideration of the basis document for the acceptance. The performance verification of the management system for waste liquid, waste gas and waste solid, the acceptance monitoring and the evaluation of the effluent discharge and the non-radioactive wastewater, the completion acceptance for the ecological issues, etc., and the applicability of the relevant technical guidelines for the NPP completion environmental protection were analyzed. It was shown that the standardization of environmental protection acceptance monitoring for nuclear power plant completion should be put forward.

Measurement and evaluation of electromagnetic radiation of 5G mobile communication base station

ZHANG Baozeng, DU Xichen, MA Xiao

RADIATION PROTECTION. 2022, 42(3): 222-228.

Abstract ( 261 )

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5G base stations are the first of the new infrastructure. The construction of high-density station brings the electromagnetic radiation of the 5G base station into the focus of environmental monitoring and public attention. Taking Beijing 5G communication base station as an example, three selected typical 5G base stations were tested with the SRM-3006 frequency selective radiation analyzer according to the “Electromagnetic Radiation Monitoring Method for 5G Mobile Communication Base Station (Trial)” (HJ 1151—2020). Based on the characteristics of monitoring equipment and 5G applications, the test, with assistance of the terminal, simulates various working conditions by selecting different equipment parameters, application scenarios and test environments. The test result is lower than the electromagnetic environment control limit, which indicates that the electromagnetic radiation level of the 5G base station is generally controllable. By analyzing the test data, it is recommended that the monitoring instrument RBW be set to 300 kHz, the amplitude to 5 V/m, the noise suppression to 3 dB, the distance between the terminals and the probes to 1m, the scenario mode to data transmission mode (download 3 GB file), and deployment direction to the antenna major lobe. Thus, the monitoring results can be reproduced, the current status of the 5G base station electromagnetic radiation environment can be acquired, and at the same time it can be referred by the monitoring agency to accurately measure the electromagnetic radiation of the 5G base station.

The effect of ⁶⁰Co γ irradiation on the electrostatic adsorption efficiency of protection masks

DAI Yongzhi, XIA Houqiong, CAO Jinjia, XIAO Hailiang, CHEN Qiang, LI Fang

RADIATION PROTECTION. 2022, 42(3): 229-235.

Abstract ( 149 )

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Respiratory protectiion masks have been widely used during the COVID-19 pandemic. Due to the shortage of supplies, medical researchers have tried to disinfect and reuse the masks, including sterilization by ionizing radiation. Based on the gamma irradiation device of Shanghai Jinpengyuan Irradiation Technology Co. Ltd., the KN95 and KN100 respiratory protection masks are irradiated to study the influence of different doses and dose rates on the filtration efficiency of the masks. The iron plate shielding and the shielding of the irradiated items of the production line are used to generate two sets of radiation field with dose rates(1.9 kGy/h,3.66 kGy/h). The absorbed doses of the masks are measured with a silver dichromate dosimeter, Harwell Amber 3042 dosimeter, and UV-2450 ultraviolet spectrophotometer. Both masks conform to the standard GB 2626—2019, so the recommended method in the GB is used to measure the filtration efficiency on particulate matter. The measurement data were processed, and the influence of the radiation dose on the electrostatic collection efficiency of the mask was estimated. The results show that the filtration efficiency of the two masks decreases rapidly with the increase of the absorbed dose, regardless of the high or low dose rate. In the end, the filtration efficiencies of the KN95 and KN100 masks are maintained at 68.2%-72.9% and at 89.7%-93.7%, respectively. Ionizing radiation eliminates the static electricity on the protection masks. The electrostatic collection efficiency of single mask fiber of KN95 accounts for 80.1% of the total collection efficiency, and for KN100 it accounts for 72.5%.

Development of integrated radiation protection information perception and management and control platform for nuclear power plant

BA Jun, XIN Kaiqiang, FAN Chong

RADIATION PROTECTION. 2022, 42(3): 236-243.

Abstract ( 79 )

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From the perspective of radiation protection business and information management and control for multi-unit nuclear power plant, this paper described the design idea of radiation protection information perception, the business scope, system functions and the relationship of IT technology. This paper also discussed the radiation protection information management and control platform architecture according to the general principles of information system design. Finally, the informational, professional and standardized management of the integration of radiation protection, ensures the integrity and effectiveness of the integrated control process and improves work efficiency. At the same time, it could also help prevent the probability of accidents caused by human factors and better improve the control level of radiation protection in nuclear power plants.

Influence of electron irradiation on the performance of Gaomiaozi Ca-bentonite

LIU Wei, LIANG Dong, YANG Zhongtian, LIU Yuchen, LI Honghui

RADIATION PROTECTION. 2022, 42(3): 244-251.

Abstract ( 72 )

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In order to study the effect of electron irradiation on the performance of Gaomiaozi Ca-bentonite, the microstructure and some physicochemical properties were analyzed with different cumulative radiation doses. The results showed that electron radiation changed the cell parameters and the size of montmorillonite, destroyed Si—O and Al—O bonds in the structure, reduced the cation exchange capacity and layer charge as well as expansion index, increased the solubility of Si and Al, and weakened the adsorption capacity of ¹³⁷Cs and ⁹⁹Tc. Compared with unirradiated samples, when cumulatively dose was up to 5 MGy, the swelling index reduced by 18.65%, the distribution coefficients of ¹³⁷Cs and ⁹⁹Tc decreased by 50.85% and 58.58%, and the solubility of Si and Al increased by 125% and 199%, respectively. It is proposed that the effect of electron irradiation on bentonite performance should be considered in the design and safety evaluation of backfill materials for geological disposal repository.

The impact of additional Cu filtration on radiation dose in digital chest radiography

MIN Gaoyu, LI Xin, ZHAO Feng, HE Wei, HU Yibin

RADIATION PROTECTION. 2022, 42(3): 252-256.

Abstract ( 131 )

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By using the digital X ray fluoroscopy camera system produced by Siemens, under different additional copper filters (0, 0.1, 0.2, 0.3 mm), chest photography is performed on PMMA phantoms of different thicknesses. Using the contrast-to-noise ratio to evaluate the impact of different additional copper filters on image quality, and using a radiation dosimeter to record the entrance surface dose under different copper filters, in order to explore the effects of additional copper filters on the body surface dose in digital chest X ray photography. The results show that under different additional copper filters, the contrast-to-noise ratio of the image does not change significantly. Under the PMMA phantoms with different thicknesses, the entrance surface dose decreased by 24%-29%, 33%-42% and 39%-47%, after adding 0.1 mm copper, 0.2 mm copper, and 0.3 mm copper respectively, compared with the absence of copper filtration, and the difference was statistically significant (p<0.05). It shows that for the digital chest X ray photography, the appropriate increase of copper filtering will not affect the image quality, but it can effectively reduce the body surface dose.

Health Phys. Abstracts,Volume 122,Number 3

RADIATION PROTECTION. 2022, 42(3): 258-260.

Abstract ( 28 )

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