Table of Content

20 July 2014 Volume 34 Issue 4

  

Study on Noble Gas ¹³³Xe and ⁸⁵Kr in Gaseous Effluent at TQNPP and its Monitoring

Li Houwen, Wang Bin

RADIATION PROTECTION. 2014, 34(4):  193-198. 

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By analyzing the production, transfer and release mechanism of noble gas from the Third Qinshan Nuclear Power Plant (TQNPP) CANDU6 reactors, derived the origin of calculation errors for noble gas emissions in the radioactive source term report, and further set forth the quantitative relationship of major noble gas including¹³³Xe, ⁸⁵Kr and ¹³¹mXe in the effluent of CANDU6 reactors. Therefore, the estimation of ¹³¹mXe and ⁸⁵Kr, which have much higher lower limit of detection, can beachieved by measuring the activity of ¹³³Xeinstead, and thus greatly reduce nuclear statistics of noble gas emissions. This method is also applicable to PWR reactors.

Chinese Reference Human Voxel Phantoms for Radiation Protection: Development, Application and Recent Progress

Pan Yuxi, Qiu Rui, Liu Liye, Ren Li, Zhu Huanjun, Li Junli

RADIATION PROTECTION. 2014, 34(4):  199-205. 

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This paper presents the work of constructing Chinese reference human voxel phantoms, taking Chinese reference adult female voxel model for example. In this study,a site-specific skeleton structure was built, some radiation sensitive organs were supplemented. Organ sub-segmentation was taken into account. The constructed phantoms include almost all radiation sensitive organs required by ICRP new recommendation. Masses of the organs are almost consistent with the Chinese reference data within 5%. The Chinese reference human phantoms have been applied both in internal dosimetry and external dosimetry. The results provide fundamental data for Chinese radiation dosimetry. In addition, the newly established detailed breast model and micro-bone model were introduced.

Improvement and its Validation to the Flue Gas Cleaning System in Low-level Waste Incinerator

Zheng Bowen, Xu Wei, Yang Lili, Wang Peiyi, Li Xiaohai, Yang Liguo, Zhang Xiaobin, Wang Xujin, Li Chuanlian, Jia Chengming, Chu Haoran

RADIATION PROTECTION. 2014, 34(4):  206-213. 

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Problems including material corrosion and redundant waste water have been found in ZRF15 radioactive waste incinerator after several years' operation. Improvements were made in the design of ZRF25 in terms of the technical process and mechanism of the flue gas cleaning system. The initial temperature of flue gas in quench was decreased. A pre-filter was installed before HEPA. The waste water treatment system was constructed. The material of equipment was improved. Results of cold and hot commissioning demonstrate the cleaning effect is desirable, the operation safety is improved, the equipment had better corrosion resistance, and the secondary waste is decreased.

Experimental Study on Aerosol Behavior in Radon Chamber

Zheng Pinghui , Zhang Lei , Liang Juncheng , Guo Qiuju

RADIATION PROTECTION. 2014, 34(4):  214-217. 

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Of all the dynamic processes in an enclosed and still radon chamber, deposition and coagulation of aerosol particles are the dominant processes on deciding aerosol activities. A simple experimental method to determine the corresponding coefficients of deposition and coagulation of aerosol particles was applied in our study. The result shows that as particle diameters increase from 58.7 to 436.4 nm, deposition coefficients decrease from 2.11×10^-5 s^-1 to 1.55×10^-5 (282.5 nm), then slowly increase to 1.72×10^-5 s^-1 and the coagulation coefficients decrease from 2.12×10^-9 cm³·s^-1 to 3.82×10^-10 cm³·s^-1. Compared with previous researches, they have the similar range of variation. In an environment with aerosol particle concentration of 10 000 cm^-3, the most stable particle size is 252.6 nm according to the decay rate influenced by both deposition and coagulation and it takes 40 min for the particle concentration to decrease by 5%. These data are valuable for the accurate control of aerosol and radon progeny in the radon chamber.

Cement Solidification of Simulated High Saline-alkali Low and Intermediate-low Level Radioactive Liquid Waste

Gao Ya, Li Yuxiang, Ma Xue, Wu Lang, Wu Jiang

RADIATION PROTECTION. 2014, 34(4):  218-223. 

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By adding slag, fly ash and zeolite as mineral admixture modifying the ordinary Portland cement, a process recipe of big solid solubility, low exudation rate, good flow ability and low nuclide leaching rate was obtained. Influences of material composition, liquid-cement ratio, salt concentration and coagulant over extended fluidity, bleeding rate and setting time were investigated. Results show that: use mineral admixtures instead of cement can exert pozzolanic effect and water-reducing effect, improving the waste liquid capacity and bleeding and salting-out of the solidification form; the slag and fly ash can improve the fluidity of paste, zealot significantly prolong the setting time; As the salt concentration increases, the expansion of fluidity and bleeding rate decreases, the setting time extends; Triethanolamine can effectively shorten the construction of cement solidification time. When the content is 1%, setting time of PSFZ shortened to 4 h 22 min , final setting time shortened to 5 h 2 min, satisfies the requirement of national standard.

Application of Extreme Value Distribution Function in the Determination of Standard Meteorological Parameters for Nuclear Power Plants

Jiang Haimei, Liu Xinjian, Qiu Lin, Li Fengju

RADIATION PROTECTION. 2014, 34(4):  224-233. 

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Based on the meteorological data from weather stations around several domestic nuclear power plants, the statistical results of extreme minimum temperatures, minimum central pressures of tropical cyclones and some other parameters are calculated using extreme value Ⅰ distribution function (EV-Ⅰ), generalized extreme value distribution function (GEV) and generalized Pareto distribution function (GP), respectively. The influence of different distribution functions and parameter solution methods on the statistical results of extreme values is investigated. Results indicate that generalized extreme value function has better applicability than the other two distribution functions in the determination of standard meteorological parameters for nuclear power plants.

Development and Test of a Radioactive Plume Simulator

Jin Chenghe, Wei Yingjing, Wang Yong, Huang Yawen, Feng Mei, Zhang Qingli

RADIATION PROTECTION. 2014, 34(4):  234-239. 

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The response to small dose variation is an important performance indicator for environmental γ radiation monitor.This paper introduces a radioactive plume simulator and the test result for its radiation field dose rate. The components of this device include a ¹³⁷Cs source and its transport system, source shieldings, lead attenuators of different thickness, and a controller system. The air Kerma rate at 3 m from the radiation source and 1m above ground was obtained by MC simulation and G(E) function method, and the difference between two method is within 5%.This device can provide a radiation field over the range of 10 nGy/h—50 nGy/h, when loading the MBq grade ¹³⁷Cs radioactive source, can be used to testing the performance of response to small dose rate variation for environmental γ radiation monitor.

Application of Stokes Sedimentation Law to Granular Size Classification of Radioactive Polluted Soils

Gan Zongyu, Li Weiping, Zeng Ke, Jin Yuren, Feng Tiancheng

RADIATION PROTECTION. 2014, 34(4):  240-243. 

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The distribution of radioisotopes in soil of small particle size is very important for the evaluations of the resuspension and personal radiation protection, as well as the research of nuclides migration. According to Stokes sedimentation law, the soil of a particle size less than 50 μm, from a radioactive pollution area, was classified in a barrel which was specifically designed. ²⁴¹Am of the classified samples were detected by HPGe γ spectrometer. The results showed that the quality purity of different granular size was larger than 50% by using optimized density of soil and 1.25 times′ the theoretical sedimentation time. For the suspensible fine grain from the radioactive pollution area, the fraction of the quality and ²⁴¹Am was less than 6% and 2% respectively.

Research Progress on Fingernails Electron Paramagnetic Resonance Signal and its Dosimetric Properties

Wang Liang, Zhang Haiying, Zhang Wenyi, Liu Zhongchao, Cui Songye, Jiao Ling

RADIATION PROTECTION. 2014, 34(4):  244-249. 

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After being irradiated by X-rays or γ-ray, new free radicals would produce within the fingernails. Using electron paramagnetic resonance (EPR) technique, signals representing free radicals can be detected and form an electron paramagnetic resonance spectroscopy. EPR signal formation, method of abtaining radiation-induced signal, signal stability and its affecting factors were discussed in this paper.

A Method for Determining ¹³⁷Cs in Seawater by Using ¹³⁴Cs as Tracer

Li Zhou, Li Pengxiang, Gao Zequan, Song Hailong, Han Yuhu

RADIATION PROTECTION. 2014, 34(4):  250-254. 

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The usual method for the determination of ¹³⁷Cs in seawater is to enrich the nuclide using radiochemical procedure, and then measure the gamma-ray spectrometry with a high efficiency HPGe detector. But this method uses a fixed chemical recovery and will produce about 10%—20% measure error. In this paper, it is found that using ¹³⁴Cs as a tracer can notably reduce the error. Pre-experiments have been done to study the effects of factors on the chemical recovery. According to the results, an analysis process is suggested: transfer 50 liters environmental seawater to the container first, adjust its pH≤2; then add moderate Cs carrier and about 1.0 Bq ¹³⁴Cs, and add 10 g AMP after stir well;Finally stir about 4.0 hours manually, and then measure. When the measure time is 80 000 s, the LLD is 1.4 mBq/L, and the measure error is less than 5%. This method is not suitable for nuclear accident emergency monitoring.

Investigation of Rare Earth Natural Radionuclide in Gannan Region, Jiangxi Province

Liu Huiping, Zhong Minglong, Hu Yongmei

RADIATION PROTECTION. 2014, 34(4):  255-257. 

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In order to identify the types, level and migration law of natural radionuclide in ionic rare earth during its development and utilization process, the natural radionuclide in raw ore, waste residues and wastewater of south ionic rare of Gannan region, Jiangxi province were investigated.The results showed that: the natural radionuclide in rare earth raw ore in An'yuan and Longnan is with high content, in which the specific activities of natural U, ²²⁶Ra and ²³²Th are 3.69×10⁴, 8.33×10³ and 3.40×10³ Bq/kg respectively; And the specific activities of the acid-soluble slag are 2.58×10⁴, 2.81×10⁴ and 2.75×10⁴ Bq/kg respectively; The radioactive level of natural U and ²³²Th in some rare earth tailings, and the specific activity of natural U in the neutralizing slag of some individual enterprises is higher than national standards' exemption level (1 000 Bq/kg). Also, the total content of Th and U in the efflux wastewater of some rare earth enterprises efflux wastewater are higher than the national emission standards limit (0.1 mg/ L).

Outage Collective Dose Control at Tianwan NPP

Zhu Mingshan, Wang Zhibing, Li Zhonghua, Chen Dawu, Chen Hao, Li Zexiang

RADIATION PROTECTION. 2014, 34(4):  258-264. 

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This paper analyzes the factors that influence the NPP's collective dose. The practice and experience in controlling collective dose at Tianwan NPP are introduced from different angles such as organizational management,process control, source item control,process improvement,benchmarking comparison,contractor management,and whole staff participation. It also provides references to the optimization of radiation protection at NPPs.