RADIATION PROTECTION

Dose investigation of high gamma rays in operating nuclear power plant

Chen Faguo, You Zhaojin, Wang Bin, Zhang Qingli, Shen Huaya, Han Yi

RADIATION PROTECTION. 2016, 36(1): 1-6.

Abstract ( 64 )

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During the operation of nuclear power plant, there are radioactive nuclides in the reactorcoolant system, ¹⁶N etc, which decay with emission of high energy gamma rays. But most of the portable gamma dosimeters are not suitable to measure the dose of high gamma rays due to the weakness of energy response. In order to investigate the radiation level of high energy gamma rays at different areas of reactor building,spectra were measured using NaI(Tl) detector during the operation of a nuclear power plant. Then, the dose rate of high gamma rays (＞3 MeV) was calculated by using the measured spectrum and response function of detector system. The results showed that: in all fifteen measurement locations, high gamma rays were observed obviously in measured spectra of six locations, corresponding to the dose rates in the range of 1.02—30.14 μSv/h.

Mechanism analysis and calculation of vitrified HLW dissolution due to ground water erosion in the process of geological disposal

Li Honghui, Li Peng, Cui Zengqi, Wan Yaping, Jia Meilan, Liu Jianqin, Zhao Shuaiwei, Mao Liang, Liu Wei

RADIATION PROTECTION. 2016, 36(1): 7-13.

Abstract ( 28 )

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The mechanism of vitrified HLW dissolution due to ground water erosion in the process of geological disposal is analyzed. Through hydrolysis reaction kinetics, dissolution rate of vitrified HLW is calculated with different temperatures and pH values, which comes out that dissolution rate is about 0.35 g/a with 60 ℃ and pH 6, while dissolution rate is about 0.8 g/a with 120 ℃ and pH 8.5; and it can be concluded that there may be a trend for dissolution rate of vitrified HLW that increases with temperatures and acidity. Among the dimension of 1 million years, the maximum dissolution load of HLW vitrified waste is 80% with 120 ℃ and pH 8.5. When considering that the disposal temperature at 60 ℃ and the range of ground water pH is 6—10, the most conservative estimated dissolution load of vitrified HLW is less than 50% over the dimension of 1 million years.

Comparative assessment of dose rate for toad at a nuclear site in southern China

Han Baohua, Li Jianguo, Huang Peng, Han Xuelei, Gao Yan, Ma Binghui, Shang Honglian, Wang Huijuan

RADIATION PROTECTION. 2016, 36(1): 14-21.

Abstract ( 47 )

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Asiatic toad (Bufo gargarizans) was chosen as the referencing of amphibian at a nuclear site in southern China. The biological anatomy dosimetric model and environmental geometries were established. Using Monte-Carlo simulation techniques, the dose rates of target tissues/organs from media about ¹³⁷Cs, ⁹⁰Sr and ²³⁹Pu were calculated, thereby the dose rates of the whole toad body were calculated. The paper used ERICA tool and RESRAD-BIOTA code to calculate the dose rates of toad, comparing with the anatomical model. The results indicated that dose rates for internal exposure compare well among three approaches. For external exposure, differing environmental geometries assumption, the results of external dose rates were different. The anatomical model concerned with radionuclide distribution in individual tissue/organ is of great importance in investigating the biological individuals that of heterogeneous distribution of radionuclides.

Effect of environmental γ dose rate caused by airborne effluent of Tianwan nuclear power station

Guo Yinglai, Jiang Konghua, Mu Jinde, Jiang Xiyuan, Gao Tao

RADIATION PROTECTION. 2016, 36(1): 22-25.

Abstract ( 50 )

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This article analyzes and compares the measured γ dose rate values and theoretical calculated γ dose rate values caused by airborne effluence during pressure vessel uncovered at Tianwan nuclear power station, and the results shows that the measured values and the calculated values are largely consistent.Meanwhile, it is verified that the influence to environmental γ dose rate due to airborne effluent is basically at the range of natural background during the normal operation of nuclear power station.The influence mainly locates in the direction of downwind,rapidly reducing with the distance increasing, and the influence of other directions is relativelyless.

A primary study on deletion of HPRT in differentiated diagnosis between γ ray and benzo-pyrene

Liu Jiangong, Zhang Zhongxin, Dang Xuhong, Liu Hongyan, Wang Chao, Duan Zhikai

RADIATION PROTECTION. 2016, 36(1): 26-30.

Abstract ( 20 )

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To investigate the changes of deletion of HPRT exposure to γ ray and benzo-pyrene, and to find a differential diagnosis index for cell injury induced by γ ray and benzo-pyrene human peripheral blood samples from three persons were exposed to ⁶⁰Co γ rays at 10 different doses (0—5 Gy) and benzo-pyrene at 6 different concentrations (0—10 μg/mL), its DNA was isolated from white cell. The changes of deletion of HPRT exposure to γ ray and benzo-pyrene were detected by real time quantitative PCR. The relationship between deletion frequency of HPRT exon and irradiation dose represents certain linear correlation from 0—5 Gy. A linear regression equation has been obtained using statistics regression analysis software: exon-2,y=0.360 3+0.110 68x,R²=0.99,p<0.01;exon-5,y=0.429 8+0.082 3x,R²=0.93,p<0.01 while, the relationship between deletion frequency of HPRT and different concentrations (0—10 μg/mL) represents no statistical significance. There is an obvious influence on deletion frequency of exon 5 of HPRT induced by γ ray,while there is no obvious influence on deletion frequency of exon 5 of HPRT induced by benzo-pyrene,which may be a new differential diagnosis index in the future.

Discussion on the present situation of spent fuel transportation in China

Li Yue, Xiao Detao, Liu Xinhua, Qiu Shoukang, He Zhengzhong

RADIATION PROTECTION. 2016, 36(1): 31-39.

Abstract ( 53 )

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With the sustainable development of the Chinese economy, as a safe and clean energy, nuclear power is of more and more importance in the Chinese energy strategy. With the safe and reasonable increase of the nuclear power units, the output of spent fuel would thusly increase at accordingly. According to the rule of storage and transportation for spent fuel and China’s actual condition that the nuclear power plant mainly locate in eastern coastal, but spent fuel reprocessing field is located in the hinterland of northwest, problems of the huge amount, poor proximity, safe transportation of the spent fuel are all inevitable. As the link between Nuclear power plant and reprocessing plant or Final disposal site, spent fuel transportation plays an important role in the sustainable operation of nuclear fuel cycle system. With the analysis of transportation modes, transportation container, transportation regulatory and accident emergency system of spent fuel in foreign countries, the article provide some suggestions for the construction and perfection of the spent fuel transportation system in China.

Speciation and solubility of americium in Beishan groundwater

Guo Hui, Kang Mingliang, Chen Wanliang, Long Junchen, Zhao Zhun

RADIATION PROTECTION. 2016, 36(1): 40-46.

Abstract ( 45 )

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Based on the thermodynamic datapublished by OECD/NEA and the estimated saturation indices for the precipitation of secondary minerals, the influence of pH, calcite, CO₂, and humic acid (HA) on the speciation distribution and solubility of Americium (Am) in Beishan groundwater were investigated using PHREEQC software. The results indicated that Am mainly occurred as AmCO⁺₃ and AmSiO(OH)²⁺₃ at nearly neutral condition, whereas AmOHCO₃·0.5H₂O(cr) and Am(OH)₃(cr) became predominantly at alkaline condition. Therefore, alkaline Beishan groundwater is favorable for the retardation of Am. Calcite exhibited a complex effect on the solubility and mobility of Am. At pH 6—8, it can decrease the solubility of Am slightly; at pH 8—9.7, the formation of anionic Am(CO₃)^-₂ was favorable thus the solubility and mobility of Am increased in presence of calcite; whereas as pH increased to 9.7—11, calcite can decrease the solubility of Am because of the formation of AmOHCO₃·0.5H₂O(cr). When pH was fixed at 7.56, the solubility of americium decreased firstly and then increased subsequently with increasing CO₂ pressure, and reached a minimum value at 10^-2.25bar. The results also indicated that humic acid had strong affinity towards americium, and from nearly acidic to alkaline conditions it could increase the solubility and hence the mobility of americium.

Regulatory suggestions for transportation and warehousing of light bulbs containing small amounts of radioactive material in China

Cheng Weiya, Yang Hongwei, Xu Huiping, Yan Yuan

RADIATION PROTECTION. 2016, 36(1): 47-52.

Abstract ( 18 )

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The third type of radioactive substances include the equipments or products containing the radioactive material and need to regulate the transport process according to the new version of Regulations of The Safe Transport of Radioactive Material and The Classification and Catalogue of Radioactive Goods. As general consumer products, subjecting the transportation and warehousing of lamps to regulatory approval would hinder the development of the entire industry and also beimpractical for regulation. Most of countries have exempted the transportation and warehousing through analysis and demonstration. Through data collection and analysis of the status of the lamps production as well as environment impacts assessment on its transportation and warehousing, suggestions on the transportation and warehousing regulation of light bulbs containing small amounts of radioactive material in China are proposed according to the exemption requirements of the GB 18871—2002.

The design of far infrared evaporation device for treatment of liquid radioactive waste

Zhang Yongkang, Sha Sha, Chen Li, Tang Yang, Zhao Qian

RADIATION PROTECTION. 2016, 36(1): 53-59.

Abstract ( 48 )

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Nuclear Power Institute of China had manufactured the far infrared evaporation device for treatment of liquid radioactive waste. The far infrared evaporation technology had never been used for treatment of liquid radioactive waste in China. The purification coefficient of far infrared evaporation technology is higher than the other technologies, and the device is physically suitable for treatment of low quantity, chemically complex liquid radioactive waste. The far infrared evaporation device is made of transport vehicle、thermal container、liquid radioactive waste processing unit、control system and external pipes. The processing capacity is 24 L/h, the maximum salt content is 300 g/L. The result of debugging shows that the designing of device is safe and reliable,the structure of device is reasonable, performance is stable, so that meets the designing requirements.

Preliminary investigation on the radioactive level in cinder brick room

Song Weijie, Chen Ling, Duan Weizhen, Guo Jinsen, Dong Qian, Guo Luzhen

RADIATION PROTECTION. 2016, 36(1): 60-64.

Abstract ( 28 )

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The results of investigation on radioactive levels in a total of 28 different rooms in 5 different provinces and cities were reported. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the wall of the rooms, indoor²²²Rn concentrations and γ dose rates were measured respectively by Falcon 5000, RAD7 and FHZ672E-10. The results show that the mean activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K in 24 cinder brick rooms are respectively (86±30) Bq/kg, (83±20) Bq/kg, (759±207) Bq/kg, and the mean data in 4 red brick rooms are respectively (51±6) Bq/kg, (54±5) Bq/kg, (632±59) Bq/kg; And in two kinds of wall materials rooms, the mean radon concentrations are respectively (96±42) Bq/m³ and (40±4) Bq/m³, the mean γ dose rates are respectively (133±25) and (120±8) nGy/h. It was confirmed that indoor radiation levels were increasing as a result of comprehensive utilization of coal ash, through analyzing the relationship between indoor concentration of ²²²Rn or γ dose rate and the activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K; And preliminarily estimated the annual effective dose to residents caused by the used of wall materials, the range of dose relates to solid cinder brick are 1.6—4.9 mSv/a, and which relates to aerated block or hollow block are 1.8—5.4 mSv/a.

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