RADIATION PROTECTION

Radiological impacts assessment of coal-fired power plants in China

JIANG Ziying, ZHANG Yanqi, CHEN Xiaoqiu, LIAO Haitao, PAN Ziqiang

RADIATION PROTECTION. 2018, 38(3): 177-184.

Abstract ( 48 )

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Based on different installed capacities, four evaluation areas as in the north and south, coastal and inland of China, and some new survey data or parameters, the radiological environmental impact from coal power plants were assessed. Results showed that: (1) Average normalized collective effective dose to the public within 80 km from coal power plant was 2.2 man·Sv/GWa. (2) Normalized collective dose from small sized coal-fired unit (100 MW and below) was 6.0 man·Sv/GWa and 1.8 man·Sv/GWa from the large sized coal-fired unit (300 MW and above); the collective dose from the small units was about 3 times higher than that from the large ones. (3) The dominant radionuclides were ²¹⁰Po and ²¹⁰Pb, and ingestion and inhalation were primary exposure pathway. (4) Collective dose of coal power plants in different sites could vary in one order of magnitude due to the big difference of population density. Conclusions and discussion: compared with natural background level, the radiological impacts of coal power plants are very small; however, coal-fired power plant is 34 times higher than nuclear power plant. By elimination of small sized coal-fired unit and implementation of ultra-low emission technology reformation, the radiological environmental impact from coal power plants would be further reduced. At present, the ²¹⁰Po emission cannot be removed effectively by dust collectors, and this should be further studied.

The record method for radioactive materials released inliquid effluents from PWR nuclear power plants

YANG Duanjie, WEI Xinyu, FANG Yuan, LI Yang

RADIATION PROTECTION. 2018, 38(3): 186-189.

Abstract ( 44 )

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For radionuclides other than ³H and ¹⁴C in liquid effluents from PWR nuclear power plants, requirements for the sampling monitoring and the record were compared in the determination of principle radionuclides and their detection limits, and the record of measurement results. Finally, some available solutions were provided for sampling monitoring of radionuclides so as to reasonably identify the discharge of liquid effluents in PWR nuclear power plants of China.

Research on monitoring instrument setting for intake ofmain control room

XUE Na, LIU Xinjian, LIN Hongtao, MAO Yawei, QIU Lin

RADIATION PROTECTION. 2018, 38(3): 191-196.

Abstract ( 47 )

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Monitoring instruments set at the intake of main control room (MCR) are used for monitoring of concentrations of radio-nuclides or environmental dose rate to provide the switching signal to the ventilation system (VCL). During accidents, the VCL system will be switched from normal ventilation to emergency filtration ventilation according to the dose rate meter. One air intake with lower contamination will be selected and the other with higher contamination will be isolated according to the β activity detectors at emergency intakes. The settings of the monitoring instruments at the intake for MCR are very crucial to reduce the amount of radioactive substances entering the MCR and enhance the habitability of MCR envelop. This paper is devoted to the research on the settings of monitoring instrument for normal and emergency intakes of the MCR. The thresholds for switching from normal vent system to emergency system are calculated by applying one full year meteorological data of the site and considering typical accidental source term, VCL system functions and the construction features of the MCR in HPR1000 unit. The atmospheric relative concentrations and the doses of the workers in the MCR on the conditions of different switching time intervals (STI) are analyzed on basis of specific site meteorological condition and the response characteristic of monitoring instruments. The doses of the workers in the MCR are evaluated for every case and compared with the dose limits. Acceptable minimum STI of dual air intakes is recommended according to the analysis.

Radionuclide analysis of aerosol in Beijing (2013—2016)

WU Yongwei, ZENG Zhi, MA Hao

RADIATION PROTECTION. 2018, 38(3): 197-204.

Abstract ( 49 )

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The long-lived radionuclides in 34 groups of aerosol samples collected in Beijing for nearly four years were studied through low-background γ-spectrometer at the China Jinping Underground Laboratory (CJPL). Radioactivity of the nuclides ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²³²Th, ²²⁸Ra, ⁴⁰K, ⁷Be, ¹³⁷Cs were measured and their mean values were 17.47 μBq·m^-3, 21.19 μBq·m^-3, 2.39 mBq·m^-3, 11.12 μBq·m^-3, 14.43 μBq·m^-3, 226.64 μBq·m^-3, 6.98 mBq·m^-3, 2.36 μBq·m^-3 , which are within the range of background. Meanwhile, there were moderate correlations between the activity concentrations of radionuclides and environmental parameters. The values of ⁷Be, ⁴⁰K, ¹³⁷Cs and ²²⁶Ra were negatively correlated to the seasons, and ²¹⁰Pb oppositely; the value of ⁴⁰K was positively correlated to AQI.

Investigation of natural occurring radionuclides inXiangjiang river of Hengyang section

XIAO Feng, XIAO Detao, QIU Shoukang, LIU Pan, SU Jiahao, WANG Huanyu

RADIATION PROTECTION. 2018, 38(3): 206-210.

Abstract ( 49 )

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The activity concentrations of six naturally occurring radionuclides (U, Th, ²²⁶Ra, ⁴⁰K, ²¹⁰Po, ²¹⁰Pb) were investigated in four major tributaries in the Hengyang section of the Xiangjiang river (Chong Ling river, Zheng river, Lei river, Mi river) after sampling in dry season (November—December) and abundant season (April—June) in order to find out the level and source of naturally occurring radionulides . The results showed that the concentrations of ²²⁶Ra, ²¹⁰Po and ²¹⁰Pb in the Xiangjiang river (Hengyang section) were significantly higher than average level of the Yangtze River system and the Dongting Lake system. The concentrations of radionuclides in the Chongling and the Zhengshui river were abnormal and significantly higher than those for the other two tributaries and the mean values of the Yangtze River system and the Dongting Lake system over the years. Thus, radioactive pollution sources might exist adjacent to these two tributaries, and further work need to be conducted.

Research on environmental dose monitoring and optimization ofoccupational protection in PET/CT center

CHEN Meng, ZHANG Juhong, ZHANG Jie, WANG Cheng, LI Haibing

RADIATION PROTECTION. 2018, 38(3): 212-216.

Abstract ( 44 )

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The PET/CT center used ¹⁸F-FDG as a positron diagnostic drug to investigate the radiation level of the center. It provided a reference for clinical radiation protection. Radiation dose rate of each working area was measured by radiation dose rate meter. Personal annual effective dose was monitored by thermoluminescent dosimeter, and the radiation dose rate at different distances from examinees was studied. It was found that the radiation dose rate of working area and staff in PET/CT center met the national standard. The radiation dose rate was close to the environmental background beyond 3 m away from the examinee.

Application of stability category G in the inland relative concentrationcalculation by PAVAN

ZHANG Yanle, WANG Chao

RADIATION PROTECTION. 2018, 38(3): 217-220.

Abstract ( 39 )

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With the classification method of atmospheric stability in RG 1.23, the application of stability category G in relative concentration calculation by PAVAN for inland site with low wind speed and more static wind frequency are discussed. The analysis shows that the relative concentration resulting from the RG 1.23 method is about half of that from HAD 101/02, in which atmospheric stability is determined by the temperature gradient and the wind speed but does not include category G. Since the RG 1.23 atmospheric stability classification method is more precise in the classification of stable weather, it’s more effective and reasonable to use the classification of stability in RG 1.23 than that in HAD 101/02 in the input file for PAVAN code while dealing with the inland site with low wind speed and more static wind frequency.

Study on desorption behaviour of cyclohexane inactivated carbon of iodine adsorber

YU Jie, DU Jianxing, WANG Longjiang, LI Yongguo, MA Ying, QIAO Taifei, LI Yanzhang

RADIATION PROTECTION. 2018, 38(3): 222-227.

Abstract ( 63 )

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Desorption behaviors of cyclohexane gas on activated carbon of iodine adsorber was investigated. Effects of temperature, relative humidity, flow rate, cyclohexane concentration of carrier gas, and thickness of carbon bed were carefully studied to provide technical support for the application of the cyclohexane method in leakage test of iodine adsorber system. Experimental results showed that cyclohexane could be retained for about 500 min in activated carbon bed under the condition of 40 ℃ and 30% relative humidity. The retention time decreased with the increase of temperature, relative humidity, concentration of cyclohexane and flow rate of carrier gas, with the most significant effect from temperature. An experimental result demonstrated that cyclohexane could be used at high humidity conditions to test leakage of iodine adsorber because the retention time of cyclohexane in activated carbon could still reach 90 min at 100 ppm(10^-6) of cyclohexane and 80% of relative humidity.

Development of a high concentration and mono-disperse aerosol generatorfor regulating radon progeny equilibrium factor

LI Bin, LIANG Juncheng, YAN Yongjun, YANG Zhijie

RADIATION PROTECTION. 2018, 38(3): 228-233.

Abstract ( 43 )

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To meet the requirements of regulating equilibrium factor of radon and its progency, a generator of high concentration and mono-disperse aerosol based on the evaporation-condensation method utilizing diethylhexylsebacate (DEHS) droplets produced by an electronic cigarette generator and NaCl particles produced by an atomizer was developed to produce high concentration and mono-disperse aerosol. This developed aerosol generator was used in an 20 m³ radon chamber of the National Institute of Metrology. After one minute injection, the highest concentration of aerosol approached 2.26×10⁵ cm^-3 with an average particle size of 156.8 nm and a mono-disperse degree of 1.38. The equilibrium factor of radon and its progeny can approach to 0.65 with regulating of the developed generator.

ORIGEN2-based isotope inventory auto-trackingcode for Xi'an Pulsed Reactor

YANG Ning, TANG Xiuhuan, ZHU Lei

RADIATION PROTECTION. 2018, 38(3): 234-239.

Abstract ( 54 )

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For dealing with the problems like power operation history collection in reactor source term study, an isotope inventory auto-tracking method based upon ORIGEN2 for Xi’an Pulsed Reactor (XAPR) was proposed. The technical measures, such as revision on ORIGEN2 built-in cross sections, creation of interval power-averaging models for XAPR, were detailed in this paper, and a demonstration code, called ORBITER (ORIGEN2-Based Inventory TrackER), was developed to verify the method. By checking out the results of ORBITER with those yielded traditionally by ORIGEN2, it was proved that the method was technically feasible and precisely reliable. For the included benchmark example with 66.5 MW·d/tU burn-up, ⁸⁵Kr among the selected three typical isotopes was found to have the greatest deviation of 2.00%, and the inaccuracy was produced by the differentiating process of calculation case, which contributed to the major deviation. By employing computer automation, the new method could decrease the work load and time consumption dramatically, and increase the source-term data acquiring efficiency remarkably.

Suggestions on nuclear emergency exercise in China

CHEN Rong

RADIATION PROTECTION. 2018, 38(3): 240-244.

Abstract ( 84 )

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The progress and issues on national-level nuclear emergency joint exercises held twice and the provincial-level nuclear emergency joint exercises held thirteen times in China since 2009 are reviewed, and the following suggestions are proposed: To strengthen the reality of exercise, to better verify the effectiveness of inspection and training, to strengthen the technical judgment and decision analysis of drills, to pay more attentions on nuclear emergency response drills at sea and specific exercises of public opinions involving nuclear incidents, and to strengthen the research and drills on public sentiment and panic response.

The latest estimation of α value for radiation protection optimization

JIA Linsheng, FENG Zongyang, YANG Yapeng, XU Xiaoxiao, ZHANG Jiangang, WANG Ning

RADIATION PROTECTION. 2018, 38(3): 246-251.

Abstract ( 65 )

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The α value for radiation protection optimization is estimated with the combination of economic value of individual life and average loss of lifetime caused by radiation. Considering the current situation of china, four methods are used to estimate α base value: gross domestic product (GDP) method, governmental compensation regulations method, major accident compensation and willingness method. The α base value of China with a range of 50 000-610 000 RMB is recommended.

Problems on emission management of nuclearmedicine wastewater containing iodine

DENG Fei, ZHOU Ruidong, JIANG Lan, CHEN Wentao, CHENG Xiaobo, MA Xi, HAN Jing, KONG Lingfeng, YU Huiting

RADIATION PROTECTION. 2018, 38(3): 252-257.

Abstract ( 40 )

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Radiation protection and environmental effect caused by medicine containing ¹³¹I elaborated in the ICRP Publication 94 were introduced. Domestic standard rules and some problems on wastewater discharge were compared. Methods of measuring radioactivity of ¹³¹I in wastewater were discussed,and the size of decay pool required to achieve discharge standards was calculated. Some advices for discharge management of wastewater containing ¹³¹I were proposed.

Remediation process for areas affected by past activities and accidents——Brief introduction of IAEA DS468

WANG Yongxian, LIANG Yu, LIANG Dong, DENG Shaogang, LI Ning

RADIATION PROTECTION. 2018, 38(3): 258-262.

Abstract ( 79 )

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The main contents and drafting process of the safety guide DS468“Remediation process for areas affected by past activities and accidents”was introduced.

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