RADIATION PROTECTION

Research progress of measurement and transmission of H_p(3)

ZHANG Xuan, YANG Yang, LI Dehong, HUANG Jianwei, HAO Yanmei, FAN Fuyou, LIU Bo

RADIATION PROTECTION. 2021, 41(5): 385-393.

Abstract ( 81 )

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Through a comprehensive literature investigation, combined with studying the contents of the current relevant standards, this paper investigates the phantom, conversion coefficients and lens dosemeter used in the measurement process. The cylindrical phantom has been used as a phantom for eye lens dose equivalent H_p(3) dosemeter calibration. The dose equivalent conversion coefficient is mainly calculated based on the Monte Carlo method and empirical formula. The H_p(3) measurement methods are various, mainly based on thermoluminescence dosimetry system. The EU has organized three relevant inter-comparisons. The comparison result of irradiation in photon field was better than the result of irradiation in β field. However, due to the application of lead glasses and lead masks, and the division of the sensitive area of the lens, there are still problems to be solved in the measurement and transmission of H_p(3).

Analysis of the source and emission level of radioactive noble gas xenon at home and abroad

WANG Shuo, TUO Fei

RADIATION PROTECTION. 2021, 41(5): 394-403.

Abstract ( 184 )

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As an important signature to judge nuclear explosion, accurate determination of the source and activity concentration of radioxenon isotopes is of great significance for implementing the Comprehensive Nuclear Test Ban Treaty (CTBT). During the time of nuclear explosion, the four most interested radioxenon isotopes were ^131mXe, ¹³³Xe, ^133mXe and ¹³⁵Xe. However, the radioxenon gas could be also observed at the monitoring station in the downwind direction of nuclear power plants and medical isotopes productions. Therefore, one of the most important problems in nuclear explosion monitoring is to distinguish between nuclear explosion and civilian sources of radionuclides. In this paper, the source of radioxenon and emission level of the relevant measurement results were collected, sorted out, and statistical analysis of the relevant rules were analyzed. And the monitoring technology of radioxenon and analysis technology of nuclear explosion were summarized in order to provide a theoretical reference for the judgment of nuclear explosion.

Rapid separation and determination of ⁶³Ni in liquid effluents of NPP

YANG Youkun, BAO Li, YANG Hailan, SONG Qinnan, LI Pengxiang, LI Zhou, WANG Ruijun

RADIATION PROTECTION. 2021, 41(5): 404-409.

Abstract ( 107 )

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In this study, a rapid analysis method of ⁶³Ni in liquid effluents of a NPP was established by systematic investigation, using Ni specific resin as the separation and enrichment material, and low background liquid scintillation spectrometer as the measuring instrument. The recovery rate of six parallel samples was (93.2±3.6)%, and the radiochemical recovery rate was (92.1±2.8)%. The detection limit is 67.4 mBq/L, and the decontamination factors of Fe, Co, Zn and Mn are 10², 10⁴, 10² and 10⁴, respectively. The analysis period is short (less than 24 h). At the same time, the liquid effluent samples are analyzed by the established method, which proves that the method can be applied to the rapid monitoring of liquid effluents in NPP, It is found that the concentration of ⁶³Ni in liquid effluents of different types of reactors may be different.

Research on analysis methods of uranium in air and waste gas samples collected with polyvinyl chloride filter membrane

ZHANG Xiaoyan, ZHANG Guifen, HAO Yue, KONG Huai, CAO Kunwu

RADIATION PROTECTION. 2021, 41(5): 410-414.

Abstract ( 82 )

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In this paper, the optimum and most appropriate microwave digestion system was established for the analysis of uranium in air and waste gas samples collected with polyvinyl chloride filter membrane, using a microwave digestion-ICP-MS method. Results showed that, when nitric acid was used as the optimized digestion acid, the uranium standard addition recovery rate was 98.4% to 102.0%, the detection limit was 2×10^-3 ng/m³ (10 m³ of sample volume, 50 mL of constant volume) and radioactivity concentration of uranium detection limit was 6×10^-8 Bq/m³ (based on natural uranium). The uranium content in atmosphere samples was analyzed using the established method and its relative standard deviation (RSD) was 3.18%. Rapid pre-treatment and reliable data were implemented by this method which meets the requirements of fast, stable, efficient and accurate in analysis of the concentration of uranium in air and waste gas samples.

The discussion on gamma-rays characteristic peak interference correction method when analyzing radionuclide activity with gamma spectrometry

YANG Xiuyu, MENG Jiqun, LI Qingguang, WEI Yingjing

RADIATION PROTECTION. 2021, 41(5): 415-421.

Abstract ( 86 )

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Aiming at the problem of gamma-ray characteristic peak interference correction in gamma spectrometry during a CNNC Environmental monitoring labs comparison, this paper conducts measurement experiment of uranium, thorium, radium and potassium in soil. When calibrating the efficiency of the spectrometer with natural soil standard source, it is necessary to analyze whether the gamma-ray characteristic peaks are interfered by other rays, and correct the efficiency by modifying the Nuclide activity value when calculating efficiency. When analyzing the nuclide activity of the samples by Gamma-Vision software, the activity correction should be carried out if the nuclide activity calculated by different characteristic rays is quite different. The characteristic peaks (such as ²³⁵U 185.7 keV, ²³⁸U 92.6 keV) used in the calculation of nuclide activity are analyzed, the contribution of the interference peak to the measured energy spectrum (Overlapping Peak) activity is deducted. This method gives qualified ²³⁸U,²²⁶Ra,²³²Th,⁴⁰K and ¹³⁷Cs data in CNNC soil sample comparison.

¹³³Xe adsorption and sampling concentration properties evaluation

LIU Wei, LV Xueyan, QUAN Wei, YU Zhengwei, WANG Haipeng

RADIATION PROTECTION. 2021, 41(5): 422-427.

Abstract ( 88 )

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¹³³Xe is considered as a key source term in the noble gas discharge from pressurized water reactor (PWR) power plants in China. Radioactive xenon isotopes contribute only a low volume concentration in atmosphere and gaseous effluent from nuclear facilities. Therefore, increasing sampling volume is necessary for radioactive xenon monitoring. This article describes research on xenon sampling concentrating technology in the air. Some experiments on various selected materials to test their Xe adsorption behaviors were carried out and their application effect in laboratory sampling were calculated. The result shows bamboo charcoal and coconut shell charcoal in particular granularity perform well in xenon adsorption, which can decrease the detection limit of noble gas sampling in radioactive effluents.

Analysis of ⁹⁰Sr activity concentration in environmental water in Beijing

WANG Zhe, LIU Lu, LIU Zhihui

RADIATION PROTECTION. 2021, 41(5): 428-431.

Abstract ( 190 )

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The activity concentrations of ⁹⁰Sr in environmental water in Beijing are measured and their trend in the environmental water in Beijing and relevant national level are also analyzed. The activity concentration of ⁹⁰Sr in 12 sampling points were analyzed referring to the “Method of Radiochemical Analysis of ⁹⁰Sr in Water and Ash of Biological Samples” (HJ 815—2016). The detection value of ⁹⁰Sr in environmental surface water in Beijing was (4.46±1.51) mBq/L, ranging from 1.44 to 7.56 mBq/L. Among which the river system water was (5.01±1.47) mBq/L, lake reservoir water was (4.00±1.45) mBq/L. The detection value of groundwater is (2.11±0.12) mBq/L. The ⁹⁰Sr content in Beijing's environmental water is low compared with previous years results but also within the normal fluctuation range and at an intermediate level compared with other places in China. The maximum annual intake of adults caused by ⁹⁰Sr in water is 3.66 Bq/a, and the maximum committed effective dose is 0.10 μSv/a, both of which are far less than the dose limits stipulated by national standard.

Distribution characteristics of ¹⁴C in the ambient air (CO₂) of the nuclear base of China Nuclear Power Institute and annual effective dose evaluation for the public

DU Yunwu, DENG Xiaoqin, WANG Liang, OUYANG Jun, SHU Yijia

RADIATION PROTECTION. 2021, 41(5): 432-438.

Abstract ( 78 )

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Based on the monitoring data of ¹⁴C in the surrounding air of the nuclear base of China Nuclear Power Institute, from 2014 to 2017, the effective dose to be accumulated for key residential groups in various ways was roughly estimated. The conclusion shows that the difference of ¹⁴C activity concentration in the air between the comprehensive building and the labor union of Nanba is statistically significant; the difference of ¹⁴C activity concentration in the air between the comprehensive building and the water works of Mucheng is statistically significant; while the difference of ¹⁴C activity concentration between the labor union of Nanba and the water works of Mucheng is not statistically significant. The above discussed results indicat that emitted ¹⁴CO₂ diffuses and mixes rapidly in the air. The average annual ¹⁴C intakes of adults, teenagers, children and children in the residential groups near the comprehensive building were 40.55,40.52,29.10 and 19.80 kBq/a, respectively, and the relevant annual effective doses to be accumulated were 23.31, 22.91, 23.08 and 19.44 μSv/a. The maximum effective dose of ¹⁴C in adult group was 23.31 μSv/a, but it only accounted for 9.3% of the target dose (0.25 mSv). It can be concluded that the influence of ¹⁴C on the surrounding environment of nuclear base is very small under normal operation conditions of the nuclear base.

Study on perovskite solar cell and the tolerance to high-energy proton irradiation

LI Wenying, ZHAO Peng

RADIATION PROTECTION. 2021, 41(5): 439-446.

Abstract ( 105 )

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The perovskite solar cells attracted great attention owing to their low cost and high performance. SnO₂ as electron transport layer has been mostly used in the perovskite solar cells due to its excellent properties, such as good anti-reflection, suitable band gap, and high electron mobility. In this study, electron transport layer thickness, hole transport layer thickness, perovskite layer thickness, temperature, shunt resistance, and series resistance are investigated on the performance of perovskite solar cells. According to the results, the optimal thickness of SnO₂ layer, Spiro-OMeTAD layer, and perovskite layer are 40 nm, 70 nm, and 650 nm respectively. In addition, with the environment temperature increasing, fill factor and short circuit current density keep decreasing. Moreover, shunt resistance and series resistance will deteriorate open circuit voltage and short circuit current density respectively. Finally, the proton irradiation resistance of FTO/SnO₂/CH₃NH₃PbI₃/Spiro-OMeTAD/Ag can reach up to 10¹³ cm^-2. This work will provide guidance to develop high performance perovskite solar cells and the application in space environment.

Design of a radioactive waste gas treatment system for an isotope production line

ZHANG Yongkang, LUO Feng, LI Zhenchen, YANG Huiqing

RADIATION PROTECTION. 2021, 41(5): 447-452.

Abstract ( 101 )

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The advantages and disadvantages of pressurized storage decay method and retention bed adsorption method were compared to ensure its gaseous radioactive effluents generated in an isotope production line meet relevant national emission standards, based on released source term and gas flow. Referring to process designs of radioactive waste gas treatment systems in domestic nuclear power plants, a combined process of “alkali washing+freez dehumidification+adsorption drying+activated carbon retention” was proposed. The process flow and parameter design of main equipment are introduced in detail, and the loading amount of activated carbon in the retention bed was optimized and calculated repeatedly. The design of the scheme meets the requirements of the isotope production line and achieves a good comprehensive balance in terms of safety, economy and practicability. The function, system flow, system configuration and layout scheme of the designed waste gas treatment device are described with an overall design scheme, furthermore, the experimental results of some corresponding tests show that the device design meets the expected requirements.

Application practice of cross linked polyethylene HIC in U.S. disposal sites and its enlightenment to China

YAO Yong, WANG Caixia, WAN Haoyu, ZHOU Ruofan, CHEN Yong

RADIATION PROTECTION. 2021, 41(5): 453-458.

Abstract ( 91 )

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This paper briefly introduces the high integrity container (HIC) of cross linked polyethylene imported from the United States by Haiyang Nuclear Power Plant, and its application in the Clive and Barnwell disposal sites in the United States. The main problems and solutions in the application of HIC in China, such as free water content, accumulated dose, radiation decomposition gas and overpackage are discussed. It is hoped that they can provide some reference for the selection of disposal plan for cross linked polyethylene HIC in China.

Calculation of radiation field during nuclear power plant decommissioning based on the coupling of MC and point kernel integration

GUO Yufei, ZHANG Hangzhou, LIU Shuiqing, LIU Yanfang, WU Yao, WANG Li, XIAO Feng

RADIATION PROTECTION. 2021, 41(5): 459-466.

Abstract ( 95 )

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In view of the coexistence of complex and simple geometrical areas in the decommissioning site of nuclear power plants, and the requirements of speediness and accuracy for the radiation field calculation during decommissioning process, a coupling calculation method of Monte Carlo and point kernel integration is proposed. Besides, a coupling calculation program is developed. For the single source model, due to the simpleness of this model, the results of the coupling method, the point kernel integration method and the Monte Carlo method are all close, and the relative deviations are less than 10%; but the calculation speed of the coupling method is 3.5 times as fast as that of the Monte Carlo method. Then the radiation field of the multi-body source model is calculated by the coupling method and the Monte Carlo method. The results show that the calculation accuracy of the coupling method is relatively high, the deviations are less than 40%, and the calculation time is shortened to 1/5 compared with the Monte Carlo method. The decommissioning radiation field of Qinshan phase I is calculated. The results demonstrate that the calculation results of the coupling method and the Monte Carlo method differ by no more than one order of magnitude, and the calculation speed of the former increases by 3 times than the latter, indicating that the coupling method can meet the needs of decommissioning radiation field calculation of nuclear power plants.

Effect of ionizing radiation on spleen development of mice during weaning age

ZHENG Yudong, LIU Yuanduo, WANG Changzheng, HUANG Jiangrong, LIU Lian

RADIATION PROTECTION. 2021, 41(5): 467-472.

Abstract ( 91 )

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This experiment investigates the effects and mechanism of ionizing radiation on spleen development of mice during weaning age. Totally fourteen C57 mice with 21-days-old were randomly divided into two groups (control group and irradiation group, each with seven mice). The mice in the irradiation group have received the whole body X-ray radiation with the dose of 5 Gy. The samples were taken from mouse of each group at seven days after radiation respectively. The body weight and spleens were weighed and calculated spleen indicators. Biochemical method was utilized to detect the changes of peripheral blood of mice. Immunohistochemistry and western blotting were used to detect the protein expression of phospho-H₂AX in spleen. Compared to the control group,the body weights and the spleen weights of mice in the irradiation group were significantly reduced (p<0.01), indicating that radiation can significantly reduce the content of white blood cells, platelets, red blood cells and hemoglobin, as well as the expression of phospho-H₂AX (p<0.05, p<0.01). X-ray exposure could resulted abnormal functions of the spleen in weaning age mice, which may be related to the decreased expression of p-H₂AX, thus reducing the ability of DNA repair.

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