RADIATION PROTECTION

Designing and verification of a compact incineration device for low level radioactive solid waste

ZHENG Bowen, XU Wei, CHU Haoran, YANg Lili, LI Xiaohai, YANG Liguo, ZHANG Xiaobin

RADIATION PROTECTION. 2020, 40(5): 365-371.

Abstract ( 192 )

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As one of the main treatment technologies for radioactive waste, incineration is used widely in the world. Some organizations or companies, such as military units, research institutions and nuclear technology application companies could not afford the construction and operation of a general incineration facility for small amount of waste produced within their organozation. In order to solve the problems, a compact low-level radioactive waste incineration technology has been developed by China Institute for Radiation Protection. The result of verification experiment indicates the technical indicators can meet design objectives, and main pollutants in off-gas emission can meet relevant national environmental protection standards. Comparing with the general incineration facility, the compacted incineration device can run 8 hours per day, its construction area is decreased to 1/30, its construction cost and energy consumption are decreased to 1/8, and the number of operation staff is decreased to 1/6, comparing with the general incineration facility. Therefore the cost and requirements of construction and operation are decreased greatly.

The improvement and cold commissioning verification of a pyrolysis incinerating facility for Spent TBP/OK

XU Liguo, ZHANG Xidong, ZHAO Linjun, XU Peng

RADIATION PROTECTION. 2020, 40(5): 372-378.

Abstract ( 168 )

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The key pyrolysis incinerator of the first domestic pyrolysis incineration facility for low level spent tributyl-phosphate/odorless kerosene (TBP/OK) imported from A compary abroad could not operate in a steady situation during its cold commissioning phase, with the phenomena of blade block and high temperature air filter obstructing. It was found that the unstable operation was due to some defects of design and manufacture. Therefore we designed a set of magnetic stirring equipment and a high temperature air filter of sintered metal and obtained better operation effects than the original incinerator of A company abroad. Successful commissioning of the first domestic pyrolysis processing project for spent TBP/OK was achieved.

Development trend and prospect of radioactive waste incineration technology

ZHENG Bowen, TANG Can, YANG Lili, XU Wei, CHU Haoran, HE Xiaoping, ZHANG Yu

RADIATION PROTECTION. 2020, 40(5): 379-386.

Abstract ( 239 )

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Incineration is one of the main treatment technologies for radioactive wastes. Comparing with general waste incineration technologies, the radioactive waste incineration technology is more focused on interception effect of radionuclide, radiation safety of process and the adaptability to wastes. With variation of waste characteristics, increased strict requirements of environmental protection and technology improvement and innovation, the third-generation incineration technology has become the mainstream of combustible waste treatment, which includes pyrolysis incineration, steam reforming incineration and plasma incineration, and is more adaptable for treating polymer materials such as rubber, plastic and resin. The future development of incineration technology for improving volume reduction effect and being compatible with various wastes will be based on premises of overall economy and requirements of environmental protection to develop special technologies for special wastes.

Application and improvement of low & medium-level radioactive waste pyrolysis incineration technology in China

XU Wei, CHU Haoran, ZHENG Bowen, TANG Can, YU Enfa, XUE Peng, Sheng Jie, Li Xiaohai

RADIATION PROTECTION. 2020, 40(5): 387-393.

Abstract ( 172 )

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Based on the development trend of incineration technology internationally, and in accordance with the characteristics of radioactive waste management in China, the China Institute for Radiation Protection has independently developed a multi-purpose radioactive waste pyrolysis incineration technology, which has been used in China for nearly 15 years. Three incineration facilities have been built. These incineration facilities have treated a large amount of low-level waste through their operation, with characteristics of good cleaning effect, good volume reduction effect, and good radionuclide distribution control. The stability and reliability of the incineration system were verified with proved advancement of pyrolysis incineration technology. Some problems of corrosion which occurred in early incineration facilities are solved, with the effect of improved safety and stability of system operation, reduced amount of secondary waste, continuous improvements on automatic level of the incineration system, and increased proportion of plastics and rubber contents in treated wastes, which consummating the domestic pyrolysis incineration technology.

An investigation on discharge and analytical methods of ⁵⁵Fe in liquid effluents from PWRs of nuclear power plants

SHA Xiangdong, HUANG Yanjun, ZENG Fan, SHANGGUAN Zhihong, JIANG Jing, WU Liansheng, CAO Zhonggang, CHEN Chaofeng

RADIATION PROTECTION. 2020, 40(5): 394-401.

Abstract ( 175 )

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This paper focuses on sources investigation of ⁵⁵Fe in liquid effluents from pressurized water reactors (PWRs) in nuclear power plants and relative analytical methods and provides some suggestions on development of ⁵⁵Fe monitoring in liquid effluents of nuclear power plants. The discharge amounts were statistically analyzed by extracting the data from public annual effluent reports of 41 US PWRs during 2005-2017 (total 871 reactor-years), which would help us to understand the necessity of ⁵⁵Fe monitoring in liquid effluents in discharge supervision of nuclear power plants. The statistical results showed that the electricity normalized discharge amounts (geometric averages) for each PWR mainly ranged from 5.18×10^-7 to 8.14×10^-5 GBq/GWh with an average of 1.52×10^-5 GBq/GWh, with above 12% of the total fission and activation radionuclides which ranked from the first to the forth. From a typical discharge volume of a Gigawatt scale PWR, the estimated discharge concentration of ⁵⁵Fe about 10.7 Bq/L would be deduced. Meanwhile, the analytical methods of ⁵⁵Fe were extensively investigated and the monitoring method standardization of ⁵⁵Fe in liquid effluents is suggested, especially for a rapid analytical method of chromatography separation and liquid scintillation measurement.

Study on a humidity controllable radon chamber system based on soil-radon

MAO Yucai, WANG Yunxiang, ZHANG Lei, GUO Qiuju

RADIATION PROTECTION. 2020, 40(5): 402-407.

Abstract ( 153 )

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Radon is the major components of the natural radiation background, and radon measurement is important for radiation environmental monitoring. Radon chamber, used for the calibration and performance check of radon monitors, plays an important role during the procedure of quality control for radon measurement. Conventional radon chamber generally consists of standard radium sources and volume for controlling radon concentration and humidity. While permission and safety management of standard radium source make conventional radon chambers difficult to develop and widely use. On the basis of the characteristics of soil gas which has high and stable radon concentration, a humidity controllable radon chamber system based on soil-radon is designed and constructed. This radon chamber system realizes the control of radon concentration by mixing air with soil gas in different fraction, and that of humidity by refrigeration type dryer. The research of radon chamber system made by Peking University shows the radon concentration and relative humidity can be controlled from 826-5 852 Bq/m³, and 30.8%-70.6%, respectively, and both of them can be stable for over 40 hours. This radon system gets rid of the limitation of radium sources, and is easy to be constructed and realized. It provides a possible way for in-situ calibration for radon monitors and can be widely used on quality control for radon measurement.

Measurement of water sample based on anti-cosmic ray γ spectrometer

LIU Qingyun, MA Guoxue, HU Xiang

RADIATION PROTECTION. 2020, 40(5): 408-413.

Abstract ( 166 )

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This article discuses the application of anti-cosmic ray γ spectrometer with low background level on water sample measurement. In this paper, a water standard source is used to efficiency calibration, and the difference of detection efficiency of water samples of different shapes is compared. The detection limit of the water samples measured by the anti-cosmic ray γ spectrometer is compared with other gamma spectrometers. Results when γ energy E<130 keV, the detection efficiency of marlin cup ($\phi$ 17 cm×H17 cm) is lower than the cylinder ($\phi$7.0 cm×7.5 cm) for water samples. When E>130 keV, the detection efficiency of marlin cup is higher than the cylinder sample. The detection limit of marlin cup measured by anti-cosmic γ spectrometer was one magnitude lower than that of cylinder water samples. The detection limit of the anti-cosmic γ spectrometer for the same water sample is one magnitude lower than that of the common γ spectrometer. The detection limit of radionuclides such as ¹⁴⁴Ce, ¹³⁷Cs and ⁶⁰Co in the samples of marlin cup water without pretreatment is 3.07×10^-2 Bq/L, 3.67×10^-3 Bq/L and 3.7×10^-3 Bq/L, directly measured by anti-cosmic γ spectrometer. Conclusion the anti-cosmic γ spectrometer can be used for the measurement of water samples with low radioactivity. Its advantage is that it can reduce pretreatment time, shorten sample measurement cycle, greatly reduce detection limit and improve measurement accuracy.

Experimental research on aerosol penetration efficiency of gaseous effluents from stack sampling system in nuclear power plant

YANG Yi, SHEN Fu, CHANG Xiang, MENG Dan, SHANG Jie, MA Tao, YANG Liu

RADIATION PROTECTION. 2020, 40(5): 414-418.

Abstract ( 155 )

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It will directly affect the accuracy of the effluents measurement that whether the sampling from the stack in nuclear facility is representative. Aerosol penetration efficiency is one of the key indicators of sampling representativeness. The method and requirements of aerosol penetration efficiency experiment in sampling system is introduced in this article. The penetration efficiency test with a particle size of D_a=10 μm was carried out for a nuclear power station under construction in China, and the result was 48.42%. The penetration efficiency increased to 53.21% after improving the sampling pipeline, greater than 50%, which meets the requirement of the relevant standard.

Investigation on the vulnerability of security monitoring systems for radioactive stockpiles based on radiation detection system

GAO Zhengming, ZHAO Juan, LI Suruo

RADIATION PROTECTION. 2020, 40(5): 419-426.

Abstract ( 124 )

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The security monitoring system is one of the most important components of the monitoring chains aiming at assuring nuclear disarmament procedure’s security, safety and reliability. This paper developed the vulnerability concept for the stockpile security monitoring system based on the recent developments of research on vulnerability in other areas. The influential factors were analyzed and a numerical evaluation method was raised specifically for the radioactive monitoring sub-system as a part of the stockpile monitoring system. Research results showed that there were many vulnerable factors and the system was also vulnerable. Lots of work should be done for the stockpile monitoring system to ensure the nuclear disarmament procedure’s security, safety, reliability and efficiency.

Study on adsorption properties of aluminite colloid for Cs⁺

ZHAO Yuting, PAN Yuelong, LIU Yu, LENG Yangchun

RADIATION PROTECTION. 2020, 40(5): 427-434.

Abstract ( 127 )

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The influence of adsorption time, pH value of solution, ions concentration in solution, humic acid (HA) amount and temperature on the adsorption effect were explored by calculating the adsorption amount and adsorption rate of aluminum saponite colloid for Cs⁺. The results showed that the adsorption effect of aluminum saponite colloid on Cs⁺ was best at the conditions of 20 minutes of adsorption time, 7 of solution pH, 3 mg of HA amount and 45 ℃ of temperature. The inhibitory effects of anions and cations on adsorption in the solution were:CO₃^2-> HCO₃^-> NO₃^-> SO₄^2-, Ca²⁺> Mg²⁺> K⁺. The adsorption process of Cs⁺ by aluminum saponite colloid conforms to the quasi-second-order kinetic equation and Langmuir thermodynamic model, which is a spontaneous endothermic process.

Study on air intake structures of a resin decomposition reactor through a numerical simulation method

ZHANG Yu, XU Wei, CHU Haoran, ZHENG Bowen, RUAN Jiasheng, HOU Bonan

RADIATION PROTECTION. 2020, 40(5): 435-442.

Abstract ( 131 )

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The effect of the upper air intake mode of a resin decomposition reactor in China Institute for Radiation Protection (CIRP) was investigated through numerical simulation method. It was found with this kind of simulation that there are some problems such as low air utilization rate, heat loss caused by air flow, and temperature decrease in resin decomposition reaction zone. The air intake mode of the equipment was improved through the numerical simulation method with a lower air intake mode which resulted in better air utilization rate and more uniform air distribution. However, in this case, the weakening effect of air on the temperature in reaction zone was also more obvious. In addition, as the diameter of the air inlet of the device decreases and the number of air inlets increases, the air distribution uniformity of the resin reaction zone can be significantly improved, and increasing the heating power of the device has a significant effect on increasing the temperature of reaction zone.

Study on the framework of radiation environmental regulatory system for radioactive associated minerals

LIAN Bing, SU Ziqiang, KANG Jing, WANG Yan, GU Zhijie

RADIATION PROTECTION. 2020, 40(5): 443-449.

Abstract ( 139 )

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In China there are many types of associated radioactive ores, which are widely distributed, involve many industries, and have different levels of radiation environmental protection technology. This article summarizes the current nuclear and radiation safety laws and regulations, the current status of uranium mines and associated radioactive environmental supervision. This article also points out the current deficiencies, such as incomplete radioactive pollution prevention policies, some no longer applicable provisions, lack of supporting regulations, and lack of supporting standard guidelines. Finally, this article provides suggestions for the corresponding regulatory system development and revision.

Discussion on the format and content of safety analysis report for near-surface disposal facility of LILW in China

LI Xingyu, LI Chang, WANG Xuhong, YANG Qiuyu, LV Tao, KANG Baowei, LIU Xiangyu

RADIATION PROTECTION. 2020, 40(5): 450-455.

Abstract ( 118 )

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There are no relevant guidelines about the format and content of safety analysis report for radioactive waste disposal in China at present. Therefore the requirements of safety analysis report based on existing LILW disposal projects and safety case concept proposed by IAEA are discussed in this article. Some suggestions on safety analysis report format and content are provided for preparing related standards for near-surface disposal facility of LILW.

The protection effect of Sijunzi Decoction (Four Noble Drugs Decoction) on radiation damage of human intestinal epithelial cells

WANG Chengfang, SHAO Shuai, QU Gonglin, QI Xuesong, GOU Qiao

RADIATION PROTECTION. 2020, 40(5): 456-461.

Abstract ( 207 )

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Irradiation-induced intestinal injury is a common complication caused by radiotherapy of abdominal and pelvic malignant tumors, which seriously affects the quality of patients’ life. It has been reported that Sijunzi Decoction (Four Noble Drugs Decoction) showed a protective effect on BALB/c mice after irradiation. To further explore the role of Sijunzi Decoction (Four Noble Drugs Decoction) in intestinal radiation damage, in this paper, human intestinal epithelial cells(HIEC-6)was used as the subject to investigate the protective effects of Sijunzi Decoction (Four Noble Drugs Decoction) on radiation damage. The experimental results showed that 0.95 mg/mL Sijunzi Decoction (Four Noble Drugs Decoction) could repair radiation damage on HIEC-6, reduce apoptosis, and slow down cell cycle block. The mechanism of Sijunzi Decoction (Four Noble Drugs Decoction) reducing radiation damage was related to the regulation on protein expression of Bcl-2 and γ H2AX. This work provided a reference for the treatment of radiation-induced intestinal injury by using Sijunzi Decoction (Four Noble Drugs Decoction).

Application and status of radon reduction techniques in underground facilities

SUN Qi, GAI Wenjia, JIANG Hao, YAN Yangyang, HUANG Xinjie, LIANG Yun, ZHU Jiao, SU Molong

RADIATION PROTECTION. 2020, 40(5): 462-469.

Abstract ( 244 )

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The radon concentration is higher in the underground facilities than in the open space. In order to protect people who live or work in the underground space from radiation hazard, the radon reduction practice has become a necessity. Presently, active carbon radon adsorption technique and electric radon elimination technique are the two main techniques used in the radon reduction area. Active carbon adsorption device would take too much space and be high energy consumption when high efficiency was needed. Electric radon elimination technique had high efficiency in eliminating combined type radon decay products, but it had no influence on the concentration of radon and uncombined type radon decay products. Based on the present technique, metal-organic frameworks (MOFs) and membrane gas separation module were introduced and the possibilities of these new materials and technique were also analyzed.

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