RADIATION PROTECTION

Modeling and dose estimation of pediatric X-CT examination using Monte Carlo technique

Pan Yuxi, Qiu Rui, Zheng Junzheng, Gao Linfeng, Li Junli

RADIATION PROTECTION. 2016, 36(3): 129-134.

Abstract ( 60 )

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With the rapid development and wide application of X-ray CT examination, estimation of the dose from CT exposures has become a hot research spot, especially for children since they tend to have higher radiation sensitivity than adults. In this work, a CT scanner model was developed using the Monte Carlo technique and was applied to estimate organ doses derived from simulated CT exposures with a 1-year-old voxel phantom developed by our group. As a result, a database including doses to 36 organs and tissues was built for 1-year-old children. This medical exposuredose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations. And it has been verified by measurement this method is convenient and reliable.

Research on photon external irradiation dosimetry for female squatting posture BREP phantom

Ma Lan, Liu Chunyu, Liang Xiao, Ge Yaxiong, Yan Bin

RADIATION PROTECTION. 2016, 36(3): 135-141.

Abstract ( 47 )

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By establishing female squatting posture BREP phantom based on Chinese reference female BREP phantom,this paper researched the effects of posture change to photon dose conversion coefficients. Using Monte Carlo methods, the organ dose conversion coefficients and the effective dose conversion coefficients of 21 monoenergetic photon beams from 0.01 to 10 MeV under six standard irradiation geometries were calculated. Furthermore,the differences were compared between squatting and standing postures. It is found that there were greater differences among the organ absorbed dose conversion coefficients in anterior-posterior,posterior-anterior,left and right lateral irradiation geometries. For example,the absorbed dose conversion coefficient of breast is 115.1% higher than standing position under posterior-anterior irradiation geometry at 0.03 MeV. However, the differences of the effective dose conversion coefficients are within 10% in most energy points. The differences in conversion coefficients are due to the position of arms,legs and the thickness changes in irradiation direction of rays for squatting position.

Simulation calculation on radioactive airborne effluents of CAP1400

Zhang Qiong, Chen Xiaoqiu, Wang Bo, Zhang Chunming, Guo Ruiping

RADIATION PROTECTION. 2016, 36(3): 142-148.

Abstract ( 55 )

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China Advanced Passive Nuclear Power Plant with installed capacity reaching to 1400 MW (CAP1400) is independently designed as the China's state-of-the-art 3rd generation nuclear power brand. The concentration of typical radionuclides dispersed from CAP1400 under normal operations were calculated with modified Gaussian model, considering effective height of the source, dry deposition, wet deposition, radioactive decay etc. The average annual ground level concentration of radionuclides distribution from CAP1400 was obtained by C-AIRDOS computer code on the site of Shidao Bay. The atmospheric dispersion factor and ground deposition rate were also investigated. These calculated results will provide valuable information for understanding the effect on radiation environment due to the radionuclides dispersed from CAP1400 Nuclear Power Plant under normal operations.

Changes of PIF1 gene expression induced by ⁶⁰Co γ ray in HepG2

Wang Bin, Zhang Ying, Zhao Degen, Li Zhongqiu, Yang Yang, Li Chao, Zhu Maoxiang, Gu Yongqing

RADIATION PROTECTION. 2016, 36(3): 149-153.

Abstract ( 46 )

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HepG2 cells were irradiated by 2 Gy and 4 Gy ⁶⁰Co γ ray, the mRNA was extracted and real-time PCR was used to detect the changes of PIF1 mRNA, to explore whether PIF1 involved in DNA damaged respond after irradiation. The results showed that PIF1 gene expression level in HepG2 decreased slightly at first and then increased after different doses of ⁶⁰Co γ ray, and the high expression continued about 12 h. PIF1 gene expression can be induced by ionizing radiation indicating its roles in DNA damage response, and the expression level is related to radiation doses and time.

Effects of AuNPs@MPA-PEG nanoparticles on radiosensitivity of Hela cancer cells

Ma Hongge, Liu Ruifang, Hong Chengjiao, Zhang Baoguo

RADIATION PROTECTION. 2016, 36(3): 154-159.

Abstract ( 45 )

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To investigate the effects of AuNPs@MPA-PEG on radiosensitivity of human uterine cervix cancer cell line (Hela), aqueous solutions of AuNPs about 5.4 nm were synthesized by sodium borohydride reduction of tetrachloroauric (III) acid solution in the presence of sodium citrate. Gold nanoparticles (AuNPs) were modified with MPA-PEG or PEG. The intracellular uptake of AuNPs, AuNPs@MPA-PEG and AuNPs@PEG was detected using inductively-coupled plasma ectrometer. Colon forming assay was carried out to study the cells survival rate of Hela cells after exposure to AuNPs,AuNPs@MPA-PEG and AuNPs@PEG combined with radiation. The number of AuNPs, AuNPs@MPA-PEG and AuNPs@PEG in cells and nuclei had dependence on concentration. Gold nanoparticles modified by MPA-PEG or PEG couldn’t promote cells to absorb themselves. But gold nanoparticles modified by MPA-PEG were helpful to the nuclei uptake of gold nanoparticles. At 160 kV X ray energy, AuNPs,AuNPs@MPA-PEG and AuNPs@PEG all could increase the radiation sensitivity of Hela cells. Modification by MPA-PEG or PEG couldn’t increase significantly the radiation sensitivity of Hela cells by comparison with AuNPs.

Safety classifications method for items of nuclear fuel cycle facilities

Kong Qingjun, Zhao Yulong, Zhao Xin, Wang Jing, Pan Longxuan, Sun Dequan, Zhang Xiaowei

RADIATION PROTECTION. 2016, 36(3): 160-166.

Abstract ( 38 )

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Items safety classifications which is simple and reasonable, not only can improve the safety of facilities, but also can narrow differences between the reviewers and operators, and reduce workload of the operator and designer's. This paper analyses the usage of nuclear safety functions method for safety classification of items for nuclear power plant, and the adoption of dosage guidelines to safety classification of items for spent fuel reprocessing facility, and then proposes a method of radioactive materials pack capacity to classify the safety of items for the nuclear fuel cycle facilities. Using the “unmitigated release” accident analysis method, the dose criteria of radiochemical safety 1 (250 mSv) and radiochemical safety 2 (5 mSv) are able to be translated into radioactive material package capacity criteria.

Method in defining radioactive airborne effluent emission limit value at nuclear power plant

Zhang Lingyan, Wang Yuhong, Yang Jie, Li Yong, Xiong Min

RADIATION PROTECTION. 2016, 36(3): 167-172.

Abstract ( 41 )

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In order to make the environmental public radiation dose caused by the nuclear power plant radioactive airborne effluents to meet regulatory requirements, this article discusses the design method of determining radioactive nuclear power plant airborne effluents control (exhaust velocity, exhaust concentration, ground concentration limit value) from the radiation dose limit value, the atmospheric pollutant dispersion law and nuclear power plant source characteristics,and provide a suggested limit value. The emission concentration limit determined by the above method is verified by existing nuclear power plant airborne effluent discharge alarm threshold, the rationality of the method is confirmed.

Development of drying equipment used for spent resin treatment

Liu Zhaofeng, Yan Xiaojun, Liang Dong, Li Honghui, An Hongxiang, Gao Chao

RADIATION PROTECTION. 2016, 36(3): 173-178.

Abstract ( 39 )

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Drying process is an available technology used for volume reduction treatment of radwaste, and has been applied to deal with spent resin generated from NPP in foreign. However, the study and application of the technology is still at the initial stage in China. On the basis of a series of process tests which included transporting, metering, drying, cleaning up of off-gas etc, the drying process with electric-heating, pressure controlling and agitating for spent resin treatment was achieved and a 1:1 scale prototype drying equipment was established. Verification and optimization tests of the spent resin drying treatment were carried out. The results demonstrate that the drying equipment is reliable and safe for the treatment of spent resin from NPP. Under the conditions of 280 ℃, (-70±3) kPa and 30 rpm agitation rate, 350 L resin (IRN160, nuclear class) was treated within nearly 20 h. The maximum evaporation rate, average evaporation rate and reduction coefficient is 9.92 kg/h, 6.31 kg/h and 2.4 respectively. The humidity of dried resin is less than 15%.

Research on doses to patient receiving from main types of chest X-ray examinations in Hunan province

Zhu Guozhen, Li Zhichun, Ge Liangquan, Liu Jianjun, Ling Guanghua, Tan Xiong, Yang Fenfang, Chen Donghui, Xu Zhiyong, Zhang Qizhi, Zhai Zipo, Chen Zhengxuan, Peng Junzhe

RADIATION PROTECTION. 2016, 36(3): 179-183.

Abstract ( 43 )

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With the aid of Thermoluminescent Dosimeter, survey client entrance surface dose (ESD) level caused by three main chest X-ray photography equipment in Hunan province. By stratified sampling method, 35 hospitals are selected, 607 cases of client are selected totally. Through the comparison of ESD caused by different types of equipment, in different level of hospitals, on different modes of kV, come to the following preliminary conclusions: for chest X-ray photography, the average ESD caused by high kV mode is lower than low kV mode; due to the different processing capacity of common X-ray, CR, DR imaging, the ESD caused by the three kinds of equipment usually follow the rule of X-ray machine > CR > DR; the current distribution status of these three equipment in different scale hospitals, to a certain level, can reflect average ESD caused by chest X-ray photography in different level hospitals following the rule of primary hospital> secondary hospital > tertiary hospital. Ordinary X-ray photography brings a greater risk of radiation to the client. When use it to do chest X-ray photography on client, physicians should do well indications analysis. At the same time, on the premise of no affecting to diagnosis, the staff should select appropriate exposure conditions according to the principle of “high voltage, low current, thick filter, little radiation field”.

Monitoring and evaluation on environmental protection acceptance of the first domestic interim spent fuel dry storage facility at Qinshan Ⅲ NPP

Xiao Shuguang, Tang Zhen, Wang Juan, Wu Xiaofei, Yu Danjiong, Chang Weixi

RADIATION PROTECTION. 2016, 36(3): 184-188.

Abstract ( 147 )

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The composition, operation procedure, nuclear safety and radiation protection of the first domestic interim spent fuel dry storage facility at Qinshan Ⅲ NPP are briefly introduced in this paper. Its environmental protection acceptance monitoring programme was developed in accordance with relevant laws and regulations. The dose equivalent rate was derived through the field monitoring. On the basis of the analysis and evaluation, a clear conclusion on whether the project meet the requirements for inspection and acceptance conditions or not was provided. Modification proposals were then put forward on the basis of the existing problems.

Comparasion on analytical results between gamma ray spectrometry and radiochemical method for ¹³⁷Cs in environmental samples

Wang Yingli, Du Yingxin

RADIATION PROTECTION. 2016, 36(3): 189-192.

Abstract ( 42 )

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Gamma ray spectroscopy method and radiochemical method were introduced to detect ¹³⁷Cs. The activity concentrations detected by using the two methods were analyzed through comparison. Then lower detection limit and higher sensitivity was shown in radiochemical method. Gamma ray spectrometry, with acceptable range of results, could be applied on detection of environmental samples. In addition, less time consumed and higher recovery could be achieved by the gamma ray spectrometry, which is important for emergency monitoring.

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