RADIATION PROTECTION

Further enhancement of safety culture in nuclear and radiation sectors

Pan Ziqiang

RADIATION PROTECTION. 2017, 37(5): 337-340.

Abstract ( 63 )

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This paper discusses the implication of safety culture in nuclear and radiation sectors. A viewpoint is put forward about how to accurately divide the areas involving nuclear and radiation which is deemed to be the basis for establishing excellent safety culture, pointing out the diverse range of manifestation with less safety culture. At the end, suggestions are proposed of how to strength the safety culture in the areas involving nuclear and radiation.

Application of multi-directional weighting method in D-T fusion neutron spectrum measurement

Wang Guanying, Han Ran, Ouyang Xiaoping

RADIATION PROTECTION. 2017, 37(5): 341-346.

Abstract ( 40 )

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Neutron energy spectrum is one of the most important characteristic parameters in the diagnosis of nuclear reaction process. Multi-directional weighting method was established for D-T fusion neutron spectrum measurement. The detectors were arranged at several different angles of the recoil proton outgoing direction. The final neutron spectrum was determined by the recoil proton spectrum and its corresponding weight values. The Geant4 simulation results showed that, compared with single direction detection, the multi-directional weighting method could improve the detection efficiency and the solution accuracy. The simulation data of multi-directional weighting method were compared with the neutron source and actual D-T fusion energy spectrum, and the practicability and validity of the method were verified.

Development and application of 3D dose rate field evaluation system

Tang Shaohua, Lv Weifeng, Liu Jie, Xiong Jun, Huang Qianqian

RADIATION PROTECTION. 2017, 37(5): 347-354.

Abstract ( 41 )

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To meet the needs for evaluation of 3D dose rate field by the operation departments and the design departments at nuclear power plants, three key technical issues concerning calculation, display and dose optimization of 3D dose rate filed were identified and solved with the development of software system RPOS. The RPOS system has been established and tested using the measured dose rate data in controlled zone at nuclear power plant. The results indicated that the RPOS system could be used for accurate simulation and virtual display of 3D dose rate field, as well as dose optimization of the worker at nuclear power plant. Further testing and improvements of the RPOS will be continued.

Study on the influence of thermal discharge on near field dilution of liquid effluent from inland NPPs

Liu Yongye, Yang Yang, Qiao Yahua, Chen Lu

RADIATION PROTECTION. 2017, 37(5): 355-360.

Abstract ( 28 )

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The numerical simulation of influence of thermal discharge on near field dilution of liquid effluent at a typical inland nuclear power plant in China under three discharge scenarios (bottom, in water and above water) at four depths were carried out using a three-dimensional hydrodynamic mixing zone model and the decision support system CORMIX (Cornell Mixing Zone Expert System). The results showed that the influence of temperature on the near field dilution of liquid effluent would depend on the depth of the drain. The temperature had favorable effect on the near field relative dilution of liquid effluent under the near-bottom or lower-middle layer submerged discharge mode, whereas it would have a significant adverse impact under the upper-middle layer submerged or above the water surface discharge mode.

Numerical simulation of γ radiation measurement in rainfall

Chen Ai, Zhou Ruidong, Chen Wentao, Liao Jianhua, Lai Liming

RADIATION PROTECTION. 2017, 37(5): 361-368.

Abstract ( 52 )

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A quantitative research about the effect of rainfall on gamma radiation monitoring data around nuclear power plants was carried out. First, according to the radionuclide measurement of rainfall, the key radionuclides impacting the gamma dose rate were found to be Pb-214 and Bi-214, the duration was about two hours after rainfull was over. Combining the relevant monitoring data with the decay of Pb-214 and Bi-214, the fitting equation for the effect of rainfall on gamma dose rate was obtained. The change of γ dose rate in rainfall can be predicted with the equation through inputting the first peak of the rain and γ dose rate in the case of multiple rain peaks. By applying the equation to the historical data including different rainfall intensities and different locations, the simulation results obtained were found to be consistent with the measurements. This method is meaningful to the real-time judgment of abnormal existence of artificial radionuclides in the process of rainfall around the nuclear power plant.

Analysis and evaluation of ¹³⁷Cs activity concentrations in the seawater near Tianwan nuclear power station

Liu Hanhan, Jiang Konghua, Wang Zhibing, Sun Kaibin

RADIATION PROTECTION. 2017, 37(5): 369-373.

Abstract ( 45 )

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Monitoring program and quality assurance measures of ¹³⁷Cs activity concentrations in the seawater near the Tianwan nuclear power station were described, and emission amounts of ¹³⁷Cs through gaseous and liquid pathways since commercial operation and monitoring results in 2004—2015 were given. The monitoring results were compared with background survey results and the reference value for seawater quality. It showed obvious difference in ¹³⁷Cs activity concentrations between monitoring results and the background survey results, and the monitoring results were far below the reference value for the seawater quality standard.

Comparative study on monitoring methods for regional radio-frequency electromagnetic radiation based on vehicle-mounted mobile

Wu Panfeng, Wang Guoqi, Lu Wei, Yao Yin, Wang Yue, Huang Xin

RADIATION PROTECTION. 2017, 37(5): 374-379.

Abstract ( 40 )

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Compared with the national standard method, the drive-test method is new and more convenient with more representative results and wider applicability in radio-frequency electromagnetic radiation monitoring. In this study, tests on urban radio-frequency electromagnetic radiation were carried out in Nantong, Jiangsu by both the vehicle-mounted mobile monitoring method and the national standard method. Among 20 250 valid test data obtained, 20 060 were by the drive-test method and 190 by the national standard method. The relative deviation of the monitoring results for the two methods ranged from 1.64%—7.77%, less than 10%. The average broad band electric fields for the two methods were 0.58±0.28 V/m and 0.52±0.32 V/m, respectively, with no obvious difference between the two methods. Whereas in the respect of the typical characteristics and representativeness, the drive-test method was significantly better than the national standard method. The study also found that the dense distribution of 50 Hz extremely-low-frequency high voltage transmission lines along the streets was the main reason for the higher values in the drive-test method. This influence could be eliminated by optimizing the driving route to avoid high voltage transmission lines and by data processing. The results of this study could facilitate the establishment of the national regulation concerning the drive-test method and provide a model for its national promotion and application.

Preliminary study on quantitative safety goals of the Xi'an pulsed reactor

Tang Xiuhuan, Bao Lihong, Wang Baosheng

RADIATION PROTECTION. 2017, 37(5): 380-386.

Abstract ( 46 )

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To promote the safety standards and operation management in Xi'an pulsed reactor, the construction of a system of safety goals and its quantitative value were put forward and analyzed on the basis of the result of probabilistic safety assessment (PSA), with considering of the characteristic of XAPR's defense in-depth and its operational safety level. The results demonstrated that XAPR safety goals should be supplemented with objectives of probability quantitative and radiation protection dose constraints. Safety goals were proposed including core damage frequency of less than 1×10^-5 per reactor year, and small release frequency of less than 1×10^-7 per reactor year; public dose of less than 0.1 mSv·a^-1, and occupational dose of less than 2 mSv·a^-1 in normal conditions. In accident conditious however, further work about the protection goals is expected.

Comparison on radon suppression effects of covering tests between waste rock heap and tailing ponds

Zhang Hui, Xu Lechang, Li Xianjie

RADIATION PROTECTION. 2017, 37(5): 387-392.

Abstract ( 65 )

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It is of great importance for soil covering as radon suppression approach in uranium mining and metallurgy site decommission. The results of soil covering test can provide scientific basis for the design and environmental impact assessment of decommissioning work. Two typical uranium mining decommissioning sites, waste rock heap and tailings are studied. According to the soil covering test results, the relationship between radon flux rate, soil thickness and diffusion coefficient of two kinds of sites are discussed, and the corresponding function is established. The results show that the thickness of overlying soil is significantly related to the radon suppression effect of two kinds of covering sites. The research results can be applied to guide the onsite project.

Issues on clearance of the spent resin from NPP

Luo Zhiping, Wang Chuangao, Xu Yongjun, Wang Wei, Guo Jinsen, Tu Xingming, Wen Fuping, Chen Ling

RADIATION PROTECTION. 2017, 37(5): 393-397.

Abstract ( 44 )

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Clearance of slightly radioactive contaminated spent resin in an importnat work of waste minimzation for NPP. Based on the recent developments in clearance of spent resin, existing problems with spent resin management at nuclear power plants were summarized. Technical approaches for waste minimization of spent resin were proposed. Potential disposal options for spent resin are hazardous solid waste landfill disposal and co-processing in cement kilns, when high temperature incineration disposal is currently not sufficiently approved. To improve the efficiency of minimizing such solid wastes in nuclear power plants and reduce the costs , further researches on the correlation among activity concentrations of different types of radioisotopes, spatial distribution of various radioisotopes in spent resin, on-line monitoring techniques for spent resin classification, and the classification and monitoring techniques for other solid wastes are suggested.

Experimental study on pressure maintaining time on pore structure of compacted bentonite

Liu Wei, Liang Dong, Li Honghui, Yang Zhontian, Jia Meilan, Zhao Shuaiwei, Mao Liang, Wu Yubin

RADIATION PROTECTION. 2017, 37(5): 398-403.

Abstract ( 25 )

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In order to investigate the effect of pressure maintaining time on pore structures of compacted bentonite, the samples were freezing dried and their pore structures were measured using a mercury intrusion porosimeter. The experimental results showed that, with increasing pressure maintaining time, the porosity ratio and pore volume of inter-aggregates decreased while the tiny pore volumes increased. Compared to the sample with no pressure maintaining, the porosity ratio of the sample with 60 minutes of pressure time was reduced by 4.53%, 9.40%, and its peak value of inter-aggregate pore diameter was reduced by 17.03%, 21.67%. These results can provide references for the engineering application of bentonite compaction.

Preliminary study on discharge scheme of low level liquid radioactive wastes from nuclear facility at oceanic mesoscale

Liu Tuantuan, Deng Anchang, Zhu Jun, Yu Haiyuan, Lin Jianguo, Zhang Aiming

RADIATION PROTECTION. 2017, 37(5): 404-410.

Abstract ( 54 )

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The low level liquid waste discharge scheme was studied with the normal operation of a nuclear facility in Jiangsu coast. A mesoscale radionuclide migration diffusion numerical model was established using the hydrodynamic (HD) and Advection-Dispersion (AD) modules of the simulation software MIKE21. The radionuclide migration and distribution of tritium at oceanic mesoscale were simulated in consideration of the distance from the shore, the sewage outfall azimuth, adverse wind direction, and other conditions. The preliminary results indicated that it would be advantageous to migration and diffusion of the radionuclide when the sewage outfall is set at the northeast location of the river mouth with no less than 30 km away from the shore.

Programming of code CRAMTRA 1.0 for transport consequence assessment of radioactive materials

Wang Renze, Li Guoqiang, Zhuang Dajie, Sun Hongchao, Wang Xuexin, Zhang Jiangang

RADIATION PROTECTION. 2017, 37(5): 411-417.

Abstract ( 57 )

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Code for transport consequence assessment of radioactive materials is an important tool. Model, programming and test results of the code CRAMTRA 1.0 for consequence assessment of radioactive materials transport was described in this paper.

A comparative study on regulatory requirements for emission and monitoring of radioactive effluents from nuclear power plants in China and USA

Huang Yanjun, Shangguan Zhihong, Zeng Fan, Chen Chaofeng

RADIATION PROTECTION. 2017, 37(5): 418-424.

Abstract ( 75 )

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The regulatory requirements for emission and monitoring of radioactive effluents from nuclear power plants in China and USA were compared and analyzed, and technical advices for those regulations and standards were provided for the development of nuclear power utilization in China.

Construction and optimization of radiation protection management system in radioactive operation in nuclear environmental protection engineering

Sun Yingying, He Huan, Gao Yanfeng, Qiu Guohua, Su Haiyan, Wang Long

RADIATION PROTECTION. 2017, 37(5): 425-430.

Abstract ( 34 )

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The radiation protection management system of the CNNC Everclean Co. Ltd. was constructed in the processes of planning, preparation, implementation and improvement, and the management procedures and technical design were optimized. The collective dose, per capita dose and individual annual maximum dose have been reduced significantly after the optimization, and the effectiveness of dose monitoring is guaranteed. The radiation protection management for radioactive operations in nuclear environmental protection engineering has been significantly improved.

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