Table of Content

20 November 2018 Volume 38 Issue 6

  

Measurement and simulation calculation for several important performances of H_P (10) secondary standard ionization chamber

WEI Yingjing, AN Shifeng, XIE Wenming, FENG Mei, ZHANG Qingli, YI Hengguan

RADIATION PROTECTION. 2018, 38(6):  449-455. 

Abstract ( 108 )   PDF (2360KB) ( 176 )  

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The structure and technical characteristics of T34035 H_p (10) secondary standard ionization chamber are introduced. The calibration coefficient NH and correction factor k(R, α) of H_p (10) secondary standard ionization chamber are measured. The uncertainty of the calibration coefficient N_H is 4.6% (k=2), and the uncertainty of the correction factor k(R, α) is 6% (k=2). When the radiation incident angle is less than 75 degrees, the energy response is better than ±20% in the range of 12 keV-1 250 keV, and the non-linearity of personal dose equivalent rate is better than ±3% in the range of 100 μSv/h-3 Sv/h. The k(R,α) values of some narrow spectrum N series and low air specific kinetic energy L series are simulated by MCNP5. The results show that the error between the calculated value and the measured value is within the range of ±6%. The ionization chamber meets the requirements of the secondary standard ionization chamber and can be used directly for the transmission of H_p (10) value.

Investigation on weak penetration radiation of valves in Qinshan phase II nuclear power plant

WANG Chuan, WEI Yingjing, NI Wei, LIU Liye, CHEN Chenxiang, CAO Qinjian

RADIATION PROTECTION. 2018, 38(6):  457-464. 

Abstract ( 119 )   PDF (2810KB) ( 134 )  

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The radiation sources and weak penetration radiation of the main valves in four systems of the RCP, RRA, RCV and PTR are monitored during the eight outages in Qinshan phase II nuclear power plant. ^110mAg is the main radioactive nuclide measured in valve deposition of RCV system. ⁵⁸Co,⁶⁰Co,⁹⁵Nb,⁹⁵Zr,⁵¹Cr and other radionuclides are deposited in valves of RCP, RRA and PTR systems. The associated β ray energy is mainly in the range of 500 keV. TheH·^*(10),H·′(0.07) and H·′(3) are measured for four types of valves. The value of H·′(3) /H·^*(10) is about 1.24, and the value of H·′(0.07)/H·^*(10) is about 14. According to the measurement results, monitoring of eye lens and skin dose for maitenance workers in some key valves are suggested.

Factors affecting detection limits of aerosol sampling in Fangchenggang nuclear power plant

HOU Jie, LI Wenting, HUANG Li, HAN Shanbiao, GAO Yuzhong, WANG Ruiying, LI Li, LI Bing, YUE Huiguo, CHEN Xiaoqiu

RADIATION PROTECTION. 2018, 38(6):  466-469. 

Abstract ( 120 )   PDF (1800KB) ( 113 )  

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The low limit detection (LLD) and the influencing factors for air effluent sampling monitoring in first stage of Fangchenggang nuclear power plant was studied. The LLD of different radioactive isotopes in air effluent with certain relative standard deviation under certain confidence level was calculated. The relationship of the relative standard deviation varying with net counting rate in different counting time was analyzed. The results showed that only when the radioactive release of air effluent approached to the calculated level, the air effluent monitoring was able to get a meaningful outcome. The analysis provides a reference for other nuclear power stations to make their own air effluent monitoring program.

Application of computational fluid dynamics method in the analysis of representative aerosol sampling in the pipeline of nuclearfacility

WANG Xie, REN Zhongguo, XIONG Zhonghua

RADIATION PROTECTION. 2018, 38(6):  471-478. 

Abstract ( 79 )   PDF (34229KB) ( 61 )  

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The representative sampling of radioactive gases and aerosols determines the accuracy of environmental monitoring and evaluation results of nuclear facilities. The gas pipeline flow field was simulated with CFD (Computational Fluid Dynamics,CFD).The results were compared with the requirements in ISO 2889. It shows the current sampling position does not meet the requirements described in ISO 2889. The proper positions which can facilitate effetive monitoring of radioactive effluents and provide scientific data support to environment evaluation are recommended.

Evaluation of protection performance against weak penetration by some personal protective equipment

WEI Yingjing, ZHAO Pengfei, NI Wei, WEI Xiaofeng, LIi Hua, LIU Liye

RADIATION PROTECTION. 2018, 38(6):  480-485. 

Abstract ( 140 )   PDF (2914KB) ( 140 )  

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In order to identify the protection effect of personal protective equipment on different energy β rays, the protection effects of personal protective equipment on H·′(0.07) and H·′(3) under various combinations of different energy β radiation fields were measured in ⁸⁵Kr and ⁹⁰Sr-⁹⁰Y standard β radiation fields. During the outage of the nuclear power plant,the weak penetrating radiation protection effect of personal protective equipment on some positions was measured. The results show that the protective effect of personal protective equipment on field radiation is different because of the different β/γ value of the surface of the equipment being measured. Especially in the places with strong γ rays,the protective effect of personal protective equipment on H·′(0.07) and H·′(3) is generally poor, while the protective effect of protective glasses against weak penetration radiation is rather significant. It is suggested that workers should wear protective glasses in high energy β radiation field to reduce the dose of lens. Due to the poor protective effect of personal protective equipment on high-energy β radiation,the monitoring methods and protective measures for workers working in high-energy β radiation sites are given.

Impact analysis of meteorological data forecast on trajectory migration in atmospheric transport processes

ZHANG Junfang, LV Minghua, YAO Rentai, QIAO Qingdang, ZHANG Fang

RADIATION PROTECTION. 2018, 38(6):  486-494. 

Abstract ( 68 )   PDF (9262KB) ( 32 )  

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Statistical analysis of trajectory migration simulation results from different types of data and different spatial resolution level were carried out with three different types and different basic spatial resolution meteorological data i.e. NCEP reanalysis data, NCEP forecast data and ECMWF reanalysis data from January to December in 2013. The conclusion shows that different sources and different spatial resolution meteorological data have certain correlation, though it is weak with the average horizontal migration deviation of the end of trajectory greater than 50%. Different sources of meteorological data with same spatial resolution have better correlation in trajectory migration simulation. The average horizontal migration deviation of the end of trajectory is less than 20%. The long-term accumulation of different source of global weather forecast and reanalysis products are significantly important to the study on trajectory migration in atmospheric transport simulation.

Study on methods and influence factors of mechanical leakage tests for iodine adsorbers

LIANG Fei, ZHANG Jirong, ZHANG Yuan, ZHANG Chongwen, ZHANG Zhaochen

RADIATION PROTECTION. 2018, 38(6):  496-501. 

Abstract ( 130 )   PDF (3330KB) ( 252 )  

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The applicability of several tracer gases for performance tests of iodine adsorbers were studied. Tracer gases investigated are trichlorofluoromethane (R-11), 1,1,1,2,2,3,4,5,5,5-decafluoro-pentane (Vertrel-XF), perfluoromethycylcopentane (PMCP), perfluoromethycyclohexane (PMCH), and perfluorodimethylcyclohexane (PDCH). Desorption behaviors of tracer gases from activated carbon affected by molecular weight, boiling point, temperatures, air velocity, moisture, water content of activated carbon were studied. R-11 was used in measuring mechanical leakage rates of iodine adsorbers at different levels of moisture loading. Meanwhile desorption efficiency of activated charcoal bed were measured after R-11 injection. Results show that the above alternative substitute gases (tracers) all meet the six criteria in Non-Mandatory Appendix TA-C of AG-1: Substitute Gas and Aerosol Substitute Selection Criteria. R-11 exhibited minimal desorption from activated carbon at less than 20% relative humidity of gas stream and 15% water content of activated carbon.Its result was more accurate.R-11 is now generally used in domestic nuclear power plants to measure mechanical leakage rates of iodine adsorbers.

Study on shielding material (sands) for disused high activity radioactive sources conditioning

SHEN Fu, YAO Zeen, YANG Weibing, LIANG Dong, MA Yinghao, AN Hongxiang, FAN Zhiwen, ZHOU Jinyuan

RADIATION PROTECTION. 2018, 38(6):  502-505. 

Abstract ( 131 )   PDF (5094KB) ( 119 )  

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Shielding experiment devices were established for high activity disused radioactive sources conditioning study. The shielding performance of different types of Xinzhou sands with different particle size and different density as well as different water contents were studied for engineering application. The suitable sands were chosen for high activity disused radiation sources conditioning. Results show that the dose rate will be controlled below 0.03 mSv/h by using 150 cm Xinzhou water saturated sands for construction as shielding material while conditioning 1 000 Ci ⁶⁰Co radioactive source.

The development of real-time assessment system for nuclear emergency at uranium enrichment facilities

JIA Linsheng, ZHANG Jiangang, FENG Zongyang, SUN Shutang, TANG Rongyao, YANG Yapeng, LI Guoqiang, XU Xiaoxiao

RADIATION PROTECTION. 2018, 38(6):  507-510. 

Abstract ( 87 )   PDF (3041KB) ( 136 )  

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The paper introduces the first integrated real-time assessment system for nuclear emergency at uranium enrichment facility in China. The system can assess the radiation effects of nuclear criticality accidents and UF₆ leakage accidents in a real-time manner. It estimates nuclear criticality fission number according to the readings of γ alarm dose rate instrument, and automatically assess the nuclear criticality consequence. Focusing on the heavy gas characteristic of UF₆ plume, the system combines the heavy gas model with the Gaussian model, thus simulates more accurately the UF₆ diffusion process. The development of the system solves the problem of lacking the technical support capability for uranium enrichment facility in emergency preparedness and response.

Experimental study on influence of montmorillonite content on expansion behavior of bentonite

LIU Wei, LIANG Dong, YANG Zhongtian, MAO Haijun, LI Honghui, JIA Meilan, ZHAO Shuaiwei, MAO Liang

RADIATION PROTECTION. 2018, 38(6):  511-515. 

Abstract ( 119 )   PDF (5818KB) ( 133 )  

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In order to find out the influence of montmorillonite content on swelling behavior of bentonite, the swelling pressure is tested using home-made equipment. Results show that, under experimental conditions,the indexes(maximum axial swelling pressure and radial swelling pressure)increase with the increase of montmorillonite content, and there is a linear relationship between the indexes and montmorillonite content. The maximum radial and axial swelling pressure were up to 2.03 MPa and 2.25 MPa respectively, and their ratio was 0.902 for the sample of 70% montmorillonite content. The experimental results can provide reference for design of bentonite in geological disposal.

Detection and analysis of MXR7 gene expression in human liver cells induced by radiation and peripheral blood of radiation workers

DANG Xuhong, ZUO Yahui, WANG Fang, ZHANG Jingyun, DONG Juancong, ZHANG Zhongxin, DUAN Zhikai

RADIATION PROTECTION. 2018, 38(6):  517-521. 

Abstract ( 85 )   PDF (3738KB) ( 124 )  

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In order to explore the changes of MXR7 genes expression in human liver cells HL-7702 and peripheral blood induced by radiation,the expression changes of MXR7 gene in human liver cells irradiated by ⁶⁰Co γ-ray were detected by real-time fluorescent quantitative PCR. Furthermore, MXR7 gene expression levels were detected in peripheral blood from radiation workers. Results showed that ionizing radiation can induce the change of MXR7 genes expression in human liver cells, and it is dose-related. The expression of MXR7 gene in peripheral blood from radiation workers was up-regulated to compare with the expression of non-radiation workers.

Investigation on radiation protection situation for nuclear medicine in cities of eastern China

TANG Bo, WU Wenwei, TU Yu

RADIATION PROTECTION. 2018, 38(6):  522-528. 

Abstract ( 90 )   PDF (4293KB) ( 274 )  

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Most of the current investigations on radiation protection for nuclear medicine in China were limited to a single medical institution or a small-scale area. The conclusions obtained were rather one-sided. To be more comprehensive and representative, a total of 28 medical institutions in 7 provinces/municipalities in the eastern part of China were selected and a field research on nuclear medicine departments were conducted in our study. We investigated the following aspects in 28 hospitals including site setting, equipment configuration, sources of radionuclide, site monitoring and current status of radiation protection management. It was found that some hospitals had problems in unreasonable site selection, poor equipment condition and imperfect performance testing. More attention should be paid to such problems in future radiation protection and supervision work while corresponding solutions should be proposed too.