Table of Content

20 January 2015 Volume 35 Issue 1

  

Discussion on low-level radionuclide monitoring for nuclear power plant effluent

Yuan Zhilun, Pan Ziqiang, Zhang Yanxia, Chen Xiaoqiu, Li Hongyu, Huang Donghui

RADIATION PROTECTION. 2015, 35(1):  1-8. 

Abstract ( 7 )   PDF (646KB) ( 0 )  

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The ability of low-level radionuclide monitoring for nuclear power plant effluents guarantees the quality of radioactive discharge evaluation. By changing the conventional sampling and measuring methods of operating NPPs and experimental studies on the radioactivity level of NPP effluents and their detection limits, the existing problems in the country's effluent monitoring of NPPs are discussed in this paper. The author also analyzes the difference between the current data processing results of low-level radioactive nuclide in NPP effluents and the actual discharge measurement. The experimental results show that the actual level of low-level radionuclide effluent is far below its statistical discharge, which is indeed one of the possible contributing factors of higher statistical discharge of nuclear power plant in China. Suggestions on establishing regulatory requirements of effluent monitoring detection limits for a nuclear power plant and data processing approach for low level monitoring result are proposed lastly.

Characteristics of a costal site's atmospheric boundary layer and atmospheric diffusion:A numerical simulation and analysis

Yang Zongzhen, You Chunhua, Bao Xinjie

RADIATION PROTECTION. 2015, 35(1):  9-19. 

Abstract ( 7 )   PDF (6935KB) ( 0 )  

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A Weather Research and Forecasting Model (WRF) and random walk model have been used to numerically-simulate and analysis the characteristics of mesoscale wind field and atmospheric diffusion in coastal area of a site. The results indicated that the atmospheric dispersions in this area is determined both by synopic systems and land-sea breeze circulation. Spatial variation of wind field is not obvious in synopic systems situation, which leads to the straight dispersion plume. Temporal variation of wind field, particularly the wind direction transition caused by transient of land-sea breezes, plays an important role in atmospheric diffusion. The method of random walk simulation better reflects the local atmospheric diffusion characteristics, especially in complex terrain and neutral stability situation, windward slope also appears high concentration distribution.

Study on application of SRS-19 model and R&D 128 model in radiological impact assessment of terrestrial organisms with ERICA code

Du Hongyan, Bai Xiaoping, Zheng Wei, Mao Yawei

RADIATION PROTECTION. 2015, 35(1):  20-25. 

Abstract ( 6 )   PDF (1156KB) ( 0 )  

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ERICA code is a program widely used to assess non-human species radiation effect in the world. The radiation rate of terrestrial organisms when the nuclear power plant operates normally was calculated and evaluated through ERICA code in this paper. And considering that,the concentration of nuclide as the input parameter of ERICA code is difficult to obtain,and the inert gases such as ⁸⁵Kr are not considered in ERICA code,we calculated the nuclide concentration with SRS-19 model in this paper,and take ⁸⁵Kr as example, we try to calculate the radiation effect of inert gases with R&D 128 model. It was concluded that two models are good supplement to ERICA code,and the radiation effects on terrestrial organisms within radius of 80 km of the site are acceptable.

Shielding design of radioactive contaminated metal waste packaging

Zou Wenhua, Dong Zhiqiang, Yao Zhenyu, Xu Shuhe, Wang Wen

RADIATION PROTECTION. 2015, 35(1):  26-30. 

Abstract ( 6 )   PDF (1717KB) ( 0 )  

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Focusing on the cylindrical source model to calculate γ dose field of waste packages with the relative formulae then derived. By comparing the calculated data of waste packages of type Ⅷ steel box with the monitoring data, it is found that the cylinder source model could accurately reflect the distributions of γ dose of the waste package. Based on the results of the cylindrical source model, a reasonable shielding technology applicable to waste package containers was designed to meet relevant requirements prescribed in standards about the transport and disposal of radioactive materials. The cylinder source model calculated dose distributions for single package in this paper is simple and easy to implement but slightly larger than the monitoring data providing a certain safety margin for the shielding design. It is suitable for radiological engineering practices.

Basic design and construction of an in-drum drying equipment for waste concentrates from NPPs

Liang Dong, Liu Zhaofeng, Yan Xiaojun, Gao Chao, An Hongxiang, Li Honghui, Feng Wendong, Liu Wei, Yang Weibing, Zhao Shuaiwei

RADIATION PROTECTION. 2015, 35(1):  31-35. 

Abstract ( 8 )   PDF (2020KB) ( 1 )  

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The volume reduction of waste concentrates from NPPs is a required part of the radioactive waste minimization. This paper introduces the design and development of the self-developed in-drum drying process and its prototype. Debugging had been carried out to each individual section, unit and to the whole process, with a cold test at last using simulated concentrates. Experiment results show that the equipment is safe and reliable with a volume reduction ratio about 4% and product humidity about 15%, the concentrates from NPPs can be properly disposed by the in-drum drying equipment

Primary study on microwave in-drum drying for simulated borate concentrate

Jia Meilan, Gao Chao, Liang Dong, An Hongxiang, Liu Zhaofeng

RADIATION PROTECTION. 2015, 35(1):  36-42. 

Abstract ( 7 )   PDF (1642KB) ( 0 )  

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Compared with borate concentrate cement solidification, microwave in-drum drying technology not only decreases greatly in volume, but also constrains radioactivity in a finite field. The study was designed therefore, including pre-test and pilot test. It comes out that it is feasible to dry the simulated borate concentrate by microwave in drum. During the microwave drying process, the outlet temperature can be an intuitionistic sign of subsequence feeding. In batched drying process, the first feed must be moderate to avoid microwave reflection; the less each subsequent feed is, the better the product's characters would be. Under the test condition, it is recommended that feed SBC or end drying when outlet temperature is in excess of 72 ℃; the first feed is recommended to be 2 kg SBC, and subsequent feeds can be 1 kg SBC each.

Layout design optimization of radioactive waste storage building in Yangjiang nuclear power station

Hu Yali, Shi Junyan

RADIATION PROTECTION. 2015, 35(1):  43-48. 

Abstract ( 7 )   PDF (2541KB) ( 0 )  

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There are six units planned at Yangjiang NPP, and different waste disposal methods will be used to these units. For the varied forms of waste produced and their storage vessels as well, the waste storage building needs to be redesigned. This paper will introduce the optimization about process and layout.

Approximate calculation of accumulated dose of polyethylene High Integrity Container

Wang Qiyun, Ma Xiaoqiang

RADIATION PROTECTION. 2015, 35(1):  49-54. 

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High Integrity Container (HIC) is a specifically designed and manufactured container having the following features: high intensity, high tightness, high chemical stability and high thermal stability for low and intermediate level waste disposial. Generally, HIC is categorized into macromolecule polymer container, inorganic cementing container, cast iron container and stainless steel container according to the container material. For the usage of HIC, radiation stability shall be considered as a key assessment index. This paper introduces an approximation method to calculate the accumulative dose and then accordingly to evaluate the accumulative dose of the HIC received during usage which used in the AP1000 nuclear power engineering. This method is proved to be conservative, partial security via Micro Shield and MCNP can be used for practical calculation method of the HIC's accumulative dose.

Uncertainty analysis of ¹³⁷Cs direct measurement with the monitoring and alarm device for seawater radioactivity

Su Jian, Zeng Zhi, He Jianhua, Ma Hao, Yu Wen

RADIATION PROTECTION. 2015, 35(1):  55-58. 

Abstract ( 6 )   PDF (1036KB) ( 0 )  

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Uncertainty is an important indicator for the performance of monitoring devices. Analysis and calculation of uncertainty are necessary prerequisites for correct representation of seawater ¹³⁷Cs monitoring results. The main uncertainty causes of ¹³⁷Cs direct measuring with a seawater monitoring and alarming device were analyzed. Four seawater samples from Western Pacific were measured and the results were compared with the radiochemical analyses. The main causes of the device's uncertainty were the relative uncertainty for the gamma count rate of seawater sample, the gamma count rate and the volume of ¹³⁷Cs seawater standard source. The device was proved to give consistent results with radiochemical analysis within the range of uncertainty.

Discussion on radiation environmental background investigation of nuclear power plant

Su Yongjie, Li Wenhui, Wang Jianhua

RADIATION PROTECTION. 2015, 35(1):  59-64. 

Abstract ( 6 )   PDF (950KB) ( 0 )  

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Combining the working practices of radiation environmental background investigation of nuclear power plant, the paper analyzes the present situation from the prespective of standard application and practice process respectively. Discussions including on specific monitoring programs, the application of aerial monitoring technology, the role of project outline, the timing of implementation, monitoring interface are made with recommendations proposed at last.