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Table of Content

    20 March 2021 Volume 41 Issue 2
      
    Optimization design of portable X-ray irradiation device for on-site calibration and study of its radiation characteristics
    XU Yang, LIN Min, GAO Fei, NI Ning, ZHANG Xi
    RADIATION PROTECTION. 2021, 41(2):  97-104. 
    Abstract ( 44 )   PDF (5751KB) ( 40 )  
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    A portable X-ray irradiation device for on-site calibration of fixed x and γ-ray radiation dosimeters has been developed by the Division of Radiation Metrology of China Institute of Atomic Energy. Firstly, the Monte Carlo method was used to establish the model and optimize the structure of the beam collimating aperture. Then, the reference radiation field range, uniformity and scattering radiation were simulated and verified by the TW32005 ionization chambers. The results show that the optimized aperture can effectively reduce its weight while meeting the requirements of beam collimating. The characteristics of portable X-ray reference radiation field meet the requirements of relevant standards. The portable X-ray reference radiation field characteristics meet the requirements of GB/T 12162.1. The correctness of the model and the effectiveness of the Monte Carlo method in the study of the characteristics of the portable X-ray reference radiation field are verified. The energy range of the radiation field is 60-164 keV, the air kerma rate is 0.08-565 mGy/h, and the ambient dose equivalent rate is 0.13-892 mSv/h. The result lays the foundation for the follow-up study of the on-site calibration technology using the portable X-ray irradiation device.
    Comparison of TDCR liquid scintillation analysis counters Hidex 300SL and SIM-MAX LSA3000 in the measurement of β-nuclides
    ZHANG Hui, YANG Yonggang, MA Yan, DAI Xiongxin
    RADIATION PROTECTION. 2021, 41(2):  105-111. 
    Abstract ( 35 )   PDF (4961KB) ( 11 )  
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    In this experiment, the performance differences of two TDCR liquid scintillation analyzers were compared by measuring the samples with different activities. The results show that the background and minimum detectable activity of SIM-MAX LSA3000 are lower, and the measurement of low activity samples is superior than that of Hidex 300SL. The TDCR quenching and correcting method was used to measure the conventional activity samples. The accuracy of the two liquid scintillation analyzers was good, the error was less than 1.5%, and the uncertainty (k = 2) was less than 2%. For the high activity samples whose counting rate is more than 1×105 cpm, the results of the two liquid scintillation analyzers are larger than the real data, especially the SIM-MAX LSA3000.
    Study on variation of dose field with shielding water levels in spent fuel operating hall
    YANG Lala, LIU Shengyong, YANG Xu, CHEN Qiuyang, GAO Yongjun
    RADIATION PROTECTION. 2021, 41(2):  112-118. 
    Abstract ( 29 )   PDF (8972KB) ( 10 )  
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    Under the accident conditions in which the spent fuel pool loses cooling capacity and water supply completely, the dose rate in the spent fuel operating hall of the pressurized water reactor nuclear power plant will gradually increase as the water level of the spent fuel pool decreases. In this paper, the spent fuel pool of a typical pressurized water reactor nuclear power plant is taken as the research object, and the QAD-CGGP program is used to calculate and analyze the distribution of the dose field in the spent fuel operating hall and its variation with the water level. The calculation results show that: (1) In the range of 3.786-7.736 m water layer thickness, the change of dose rate above operating platform with water layer thickness is not obvious. (2) The peak dose rate above spent fuel pool locates above the high-density grid area. (3)In the range of 3.436-4.736 m water layer thickness, the peak dose rate above spent fuel pool changes in the range of 0.914-288 μSv/h and increases exponentially with the decrease of the thickness of the shielded water layer, and dose rate above operating platform meet the radiation zoning requirements of the spent fuel operating hall. (4) The lowest shielding water level needed to meet the radiation zoning requirements of the spent fuel operating hall is +15.77 m.
    Discussion on the influence of radon concentration on the decision threshold of aerosol monitors
    ZHANG Fuguo, ZHANG Zhilong, YANG Yi, FU Cuiming
    RADIATION PROTECTION. 2021, 41(2):  119-123. 
    Abstract ( 32 )   PDF (2502KB) ( 22 )  
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    The radon concentration in the environment will affect the decision threshold of aerosol monitors. Based on the radon and its daughters generation system of China Institute for Radiation Protection (CIRP), a set of stable circuits with adjustable internal radon concentration were established, and six domestic and overseas aerosol monitors were tested, in order to explore the effect of different environmental radon concentrations on the decision threshold of the aerosol monitors. Based on large number of experiments and data, it is recommended to select the correlation between the radon concentration and decision threshold of the aerosol monitor according to the monitoring mode of the aerosol monitor. When single measurement mode or fixed cumulative measurement mode is adopted, there is a linear relationship between its decision threshold and radon concentration. When mobile cumulative measurement mode is adopted, a power function relationship between its decision threshold and radon concentration is recommended.
    Analysis of radiation protection for beam collimator at SHINE facility
    XU Yuhai, WANG Guanghong, CHEN Si, LI Zhefu, GU Duan, WANG Xiaowa
    RADIATION PROTECTION. 2021, 41(2):  124-128. 
    Abstract ( 21 )   PDF (4135KB) ( 7 )  
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    The Shanghai HIgh repetition rate XFEL aNd Extreme light facility (SHINE) under construction is located at Zhangjiang Hi-Tech Park, Shanghai. The SHINE facility consists of an 8 GeV continuous-wave (CW) superconducting linear accelerator, a 100 PW laser system, three undulator lines, and ten experimental end-stations at phase-I. The SHINE facility will be built in a tunnel 29 meters underground, with a total length of 3 km. In the tunnel of No.2 shaft, there are many beam collimators for scraping off electrons with a relatively large opening angle at the periphery of the beam halo, and the beam loss rate of the beam collimator is 1/10,000. In this paper, the Monte Carlo program FLUKA is used to simulate the Gaussian distribution of the electron beam outside 3 σbeam with its SOURCE program. The model to simulate the loss of electrons at the beam collimator is called the beam ring-type Gaussian model. The main material of the beam collimator adopts tungsten to attenuate the strong radiation caused by the electron electromagnetic shower. The model was used to analyze the activation of the beam collimator. The results show that the Gaussian distribution model can more realistically reproduce the loss of electrons in the beam collimator. Gaussian distribution model was used to analyze the activation and the results prove that the disposal of tungsten radioactive waste is not difficult.
    Content and correlation analysis of 90Sr in environmental surface water and sediment
    LI Zhou, LI Pengxiang, MA Xuyuan, SONG Qinnan, HAN Yuhu, REN Xiaona
    RADIATION PROTECTION. 2021, 41(2):  129-132. 
    Abstract ( 29 )   PDF (965KB) ( 12 )  
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    In order to study the transport process of 90Sr, a statistical analysis of the content data in 62 groups of surface water and associated sediment in different regions of China has been conducted in this paper. The results showed that the content data of 90Sr in two sample medias showed a certain linear relationship, but the overall correlation was not very strong, and no regional correlation was found. Further discussion on the factors affecting correlation was made and suggestions for the follow-up research works was put forward in this paper.
    Investigation on radioactive level of centralized drinking water sources in Gansu province (2017-2018)
    WANG Fujun, ZHANG Tangui, WANG Haishan, FANG Peng, HAO Jianguo, WANG Jupeng, REN Kunxian, ZHAO Jianing, MA Hongda, WEI Jinxiang, LIANG Xiaoye, YANG Kun
    RADIATION PROTECTION. 2021, 41(2):  133-137. 
    Abstract ( 24 )   PDF (902KB) ( 4 )  
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    In order to know the radioactivity level of centralized drinking water sources in prefecture-level cities (states) of Gansu Province, the total alpha, total beta, U, Th, and 226Ra radioactivity in centralized drinking water sources in prefecture-level cities (states) of Gansu Province were investigated in 2017 and 2018 respectively. The results show that the concentration of radionuclide activity in the water body of the centralized drinking water sources is at the natural background level of the local environment. And the corresponding environmental management countermeasures are put forward for the drinking water sources.
    Discussion on the influence of uranium-coal superimposed mining area on coal mine environment radon
    JI Dong, LIU Ying, SU Xiaoshu, LI Yuangang, ZHOU Ju
    RADIATION PROTECTION. 2021, 41(2):  138-144. 
    Abstract ( 21 )   PDF (7591KB) ( 2 )  
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    A large number of uranium-coal symbiosis deposits had occurred in the Inner-Mongolian area in China, and the uranium-coal superimposed areas were formed. In the process of uranium and coal mining and smelting, the radon produced by the decay of residual radionuclides in the uranium aquifer will seep and diffuse into the coal mining surface along with groundwater and underground pores in the mining area. In order to understand the radiation effect of radon on coal mining working surface, this phenomenon needs to be studied and analyzed. The CFD numerical simulation technology was used to simulate the radiation influence of the coal mining surface caused by the gas-liquid two-phase radon seepage and diffusion. The results show that the concentration of additional radon is between 263.22-645.54 Bq/m3 with the advance of coal mining. Measures such as strengthening ventilation and blocking measures should be taken to reduce the additional impact of radon concentration on coal mining operators.
    Evaluation of activated area in the electrostatic accelerator facilities in the reactor facility
    K. Masumoto, H. Matsumura, T. Miura, G. Yoshida, A. Toyoda, H. Nakamura, K. Bessho, T. Nakabayashi,F. Nobuhara, K. Sasa, T. Moriguchi, H. Tsuchida, S. Matsuyama, M. Matsuda, A. Taniike
    RADIATION PROTECTION. 2021, 41(2):  145-150. 
    Abstract ( 32 )   PDF (684KB) ( 22 )  
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    In order to clear the activated area in electrostatic accelerator facilities, four accelerator facilities were selected and typical neutron emission experiments were performed. Neutron flux during operation and induced activity caused by charged particles on the accelerator and its surrounding area after irradiation were measured. Also the monitored neutron flux and calculated value by Monte Carlo calculation using PHITS code were compared. It was confirmed that the results between calculated data and measured data showed the good agreement with each other. Finally, it was concluded that we have to take care the activation of beam line and target. But, it is not necessary to treat accelerator tank, surrounding materials, and building concrete as radioactive materials in case of decommissioning.
    Practice and exploration of radioactive solid waste minimization in Yangjiang Nuclear Power Plant
    YAO Zhimeng, ZHU Jianrui, FENG Jincai, ZOU Xiaowei, LIU Ziping, LI Xinxian
    RADIATION PROTECTION. 2021, 41(2):  151-156. 
    Abstract ( 22 )   PDF (911KB) ( 4 )  
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    This paper summarized good practices and experience on waste minimization management in a domestic nuclear power plant. By implementing high-integrated container (HIC) waste treatment processes and sending out flammable radioactive waste for incineration, the effectiveness and shortcomings of waste minimization measures were analysed, considering the aspects of design, technology, management, ect. Some suggestions for further improving the management of radioactive waste in nuclear power plants are also presented.
    Research on waste stacking optimization of disposal process in a near surface disposal site
    WANG Jie, GAO Yanfeng, SHENG Feng, DONG Zhiqiang
    RADIATION PROTECTION. 2021, 41(2):  157-164. 
    Abstract ( 21 )   PDF (19612KB) ( 1 )  
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    In view of the practical application of the original design disposal process of a near surface disposal site, there are related problems such as the reduction of volume utilization rate of disposal unit. This paper optimizes the original design scheme and puts forward a new design. The effects of the optimized design were analyzed from three aspects: construction cost, time, radiation dose and similar disposal site. The comparison results show that the optimized stacking plan is more suitable for the actual disposal requirements than the original design. The volume utilization rate of the disposal unit has been significantly improved. And the successful practice of the individual optimized stacking plan also achieved the expected design effect.
    Effects of N-acetylcysteine on oxidative stress, proliferation and apoptosis of HT22 cells induced by radiation
    HUANG Yue, CHEN Naiyao, ZHAO Hui, YAN Zhenyu, ZHANG Haixia, ZHAO Xuecong, ZHANG Dingping
    RADIATION PROTECTION. 2021, 41(2):  165-173. 
    Abstract ( 16 )   PDF (3311KB) ( 3 )  
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    In order to investigate the effect of N-acetyl-L-cysteine (NAC) on radiation-related oxidative stress and the proliferation and apoptosis of hippocampal neuron HT22 cells, the following process was conducted. First, HT22 cells were irradiated with different doses of X-rays (0, 2, 4, 6, 8, 10, 12 Gy), and the optimum radiation dose (10 Gy) was selected. Then experimental groups were set as follows: control (Control) group, radiation treatment (RT) group, RT+NAC group. Continue to cultivate for 24 h after irradiation, CCK-8 was used to detect cell proliferation; The apoptosis of the HT-22 cell was examined by AnnexinV/PI double labeling flow cytometry.Intracellular reactive oxygen species (ROS) was detected by DCFH-DA fluorescent probe to evaluate intracellular oxidative stress levels; Intracellular glutathione (GSH), malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were detected by colorimetry; The expression of Cleaved caspase-3, Bax and BCl-2 protein was analyzed by Western blot. Results show that: (1) The effect of 2 Gy radiation dose on cell proliferation is not obvious. When the radiation dose was higher than 2 Gy, with the increase of radiation dose the proliferation of HT22 cell was decreased (p<0.05). After radiation dose of 10 Gy, cell proliferation inhibition rate was close to 50%. Therefore, 10 Gy was used as the optimal radiation dose for the experiment. (2) Pretreatment with NAC before 10 Gy X-ray irradiation can significantly increase the proliferation rate of HT22 cells. (p<0.01). (3) Radiation treatment can significantly increase intracellular ROS and MDA content (p<0.01), meanwhile intracellular GSH content and SOD activity were reduced (p<0.01). Radiation treatment promoted the expression of apoptotic proteins: Bax and Cleaved caspase-3 (p<0.01). The apoptosis rate was increased significantly (p<0.01). NAC can reduce intracellular ROS and MDA content after irradiation (p<0.01). GSH level and SOD activity were increased (p<0.01). The expression of apoptotic proteins and apoptosis rate were reduced significantly. The above results indicate that NAC can inhibit radiation-related oxidative stress, reduce radiation inhibition of HT22 cell proliferation, and reduce apoptosis.
    Issues and improvements of liquid effluents from inland third-generation PWR site
    LIU Hongkun, DONG Liang, LIU Yan, TANG Hui
    RADIATION PROTECTION. 2021, 41(2):  174-180. 
    Abstract ( 21 )   PDF (1064KB) ( 7 )  
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    Due to the limited capacity of receiving water in inland plant site, a key issue of the inland nuclear power plant is the discharge of low-level liquid radwaste from inland NPPs. Through comparative analysis of the liquid effluent from the inland third-generation PWR and the requirements of the regulations and standards, it was found that the radioactivity (except tritium and 14C) in liquid and tritium concentration in water at 1 km downstream of plant outlet could not meet the requirements of the inland site. Therefore it is recommended to add chemical flocculation, ion exchange bed and reverse osmosis device to meet the requirement of 100 Bq/L. Discharge control has to be adjusted to fulfill national standards, which can meet the tritium discharge needs of two units, in order that the tritium concentration at 1 km downstream is less than 71 Bq/L. The tritium discharge of multiple units is recommended to use WD+CECE to achieve the purpose of separating tritium.