RADIATION PROTECTION

The comparison and analysis of excretion fraction after inhalation of ²⁴¹Am based on ICRP No.141 biokinetic model

CHEN Qianlan, LUO Zhiping, LIU Senlin

RADIATION PROTECTION. 2021, 41(3): 193-200.

Abstract ( 177 )

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Based on more advanced techniques and wider range of internal dose monitoring data from exposed human, the new biokinetic models (such as HRTM and Systematic Model) and dose convention coefficients from ICRP No.141 Publication will give us additional confidence in the data provided. The difference and similarity of the new and old models calculation results are very important for internal dose evaluation from excreta monitoring of transuranic elements inhaled. The excretion fraction calculating program of the transuranic elements' new biokinetic models from ICRP No.141 publication is established, then the urine and feces fraction of ²⁴¹Am in reference worker who has inhaled S,M,F type ²⁴¹Am aerosol (AMAD 5 μm) have been calculated respectively for the new models' and old models' results. The comparing of the results indicates big difference between the new and old model's excretion fraction results, and the committed effective doses calculated by the new and old models are also quite different. The internal dose evaluation criteria using excreta monitoring method can use the new model's results in some cases when needed in the near future.

Research on dead time of NaI(Tl) detector based on digital multichannel analyzer

YAN Yangyang, JIANG Hao, LIN Changyong, LIANG Yingchao, DAI Chuangbo, LIAO Wu, CHEN Xianglei

RADIATION PROTECTION. 2021, 41(3): 201-204.

Abstract ( 207 )

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There is dead time in the measurement of radiation by any detector. When the radiation intensity is too high and the current radiation has not been fully processed by the detector, the following radiation may not be processed, resulting in the loss of count. In practical measurement, it is necessary to accurately measure the count rate of the radiation and it is necessary to correct the dead time effect. In this paper, the dead time of the NaI(Tl) detector based on digital multichannel analyzer is analyzed theoretically and the correction method is studied. The dead time is measured by the dual source method and the effectiveness of the correction method is verified in ¹³⁷Cs radiation field.

Application of Monte Carlo simulation in predicting radiation levels of rare earth tailings

WANG Pan, ZENG Zhiwei, ZHANG Qingxian, YANG Mingli, CHU Xuyang

RADIATION PROTECTION. 2021, 41(3): 205-209.

Abstract ( 143 )

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In order to evaluate the radiation level of rare earth tailings, this paper takes thorium-containing tailings after rare earth production from typical monazite beneficiation as research object, and uses Monte Carlo simulation method to calculate the air dose rate around the thorium tailings bucket. The relative standard deviations between the simulated calculation results and the measured data did not exceed 20%, indicating that it is feasible to apply Monte Carlo simulation method to predict the radiation level of rare earth tailings.

Study on mathematical simulation of electron paramagnetic resonance (EPR) spectrum analysis of nail

YAN Changxin, LIU Yulian, JIAO Ling, ZHANG Wenyi

RADIATION PROTECTION. 2021, 41(3): 210-217.

Abstract ( 183 )

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The objective of this study is to explore the decomposition method of electron paramagnetic resonance (EPR) spectra of fingernails after water treatment, and complete dose estimation using nails as biomaterials. Using C++ to write code, visual studio 2019 Community Edition as the integrated development environment (IDE), under the platform of windows10, the effective information extraction, fitting, simulation, normalization, dose regression of electron paramagnetic resonance spectroscopy were carried out. The results showed that the residual spectra of the three groups of individual samples(RIS2+RIS5,1-10 Gy exposure)are close to a straight line, the R² of dose regression curve is greater than 0.9, and the fitting error is less than 1 Gy. For the 10 person mixed group(RIS2+RIS5,1-10 Gy exposure), R² was close to 0.9 (0.89), and the fitting error was about 1.1 Gy, while for the RIS5 fitting group, R² was greater than 0.9, and the fitting error was 4.78 Gy (5-55 Gy exposure). By fitting the EPR spectrum of fingernails with mathematical simulation, we can separate the overlapped signals into RIS spectrum, which can reduce the influence of background signal on dose reconstruction to a certain extent.

Analysis of Pu in large volume water by Ca-Mg co-precipitation and MnO₂ precipitation

LI Pengxiang, REN Xiaona, MA Xuyuan, LI Zhou, YI Wujing, ZHANG Jing, HAN Yuhu, YANG Zhimeng

RADIATION PROTECTION. 2021, 41(3): 218-222.

Abstract ( 125 )

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The method for Pu analysis in large volume water was studied by using a precipitation concentration-ion exchange method. MnO₂ precipitation and Ca-Mg co-precipitation were used in the concentration process. When the volume of water sample was 25 L, the total radiochemical recovery rate of the two precipitation methods can reach about 70%. When the volume of water sample was greater than 50 L, the recovery rate of MnO₂ precipitation decreased significantly. The total radiochemical recovery rate of 100 L water sample by Ca-Mg co-precipitation is 63.5% to 80.2%, the average value is 74.6%±5.9% (n=7), and the minimum detectable limit of ^239+240Pu is 3.1 μBq/L (volume V=100 L, recovery rate Y=74.6%, measurement time t=72 h). The content of ^239+240Pu in an actual fresh water sample was 9.32-15.6 μBq/L, and there was no result which is below detection limit when the sample volume was 100 L.

Study on analysis methods of uranium isotopes in aerosol samples based on reduction system

LI Zhou, ZHANG Jing, MA Xuyuan, LI Pengxiang, SHI Qiqi, HAN Yuhu, REN Xiaona

RADIATION PROTECTION. 2021, 41(3): 223-228.

Abstract ( 134 )

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The analysis of uranium isotopes is of great significance to the radiation dose assessment caused by uranium and the investigation of environmental pollution sources. A procedure for analysis of uranium isotopes in aerosol samples with ascorbic acid as reduction agent was established. The aerosol samples were completely melted. The analytical method had a good removal effect on interfering elements such as iron and plutonium, and the radiochemical recovery rates of uranium isotopes were in the range of 74.5% and 93.6%, with an average of 81.5%, which can meet the requirements of routine uranium isotopes analysis of aerosol samples.

Transfer of ²³⁸U,²²⁶Ra,²¹⁰Pb and ²¹⁰Po from soil to three vegetables and dose estimation after ingestion

LIANG Guoshuai, CHEN Baidi, CHEN Zhidong, DENG Fei

RADIATION PROTECTION. 2021, 41(3): 229-236.

Abstract ( 202 )

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The distribution and content of ²³⁸U, ²²⁶Ra, ²¹⁰Pb and ²¹⁰Po in roots, stems and leaves of Brassica juncea, Brassica pekinensis and Amaranthus tricolor grown in the uranium contaminated soil of Guangdong district were analyzed. The results showed that the roots were the main enrichment part. The transfer coefficients of the three vegetables were all at the level of 10^-3-10^-2. The transfer coefficients of ²³⁸U and ²²⁶Ra of Brassica juncea were correlated while the transfer coefficients of ²¹⁰Pb and ²¹⁰Po of Brassica pekinensis were also correlated. According to the preliminary estimation of committed equivalent dose for public ingestion of 1 kg those vegetables, the dose of ²³⁸U ranged from 0.001 to 0.105 μSv, ²²⁶Ra ranged from 0.004 to 0.576 μSv, ²¹⁰Pb ranged from 0.019 to 0.646 μSv, ²¹⁰Pb ranged from 0.019 to 0.646 μSv.

Study on radiation effect of reusing hydrofluoric acid containing uranium

HAN Chuncai, KONG Fanfan, CHEN Liangping, MEN Qingseng, LIAO Yunxuan

RADIATION PROTECTION. 2021, 41(3): 237-241.

Abstract ( 120 )

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To solve the treatment problem of hydrofluoric acid containing uranium produced by nuclear facility operation, the radiation effects of hydrofluoric acid containing uranium used in the production of ammonium hydrogen fluoride was studied. The results showed that the dose to the worker caused by the production process of ammonium hydrogen fluoride using hydrofluoric acid, in which uranium content is less than 0.2 mg/L, is far less than 1 mSv/a and the uranium content in the product is less than 1 Bq/g. For the perspective of radiation effect, it is feasible to produce ammonium hydrogen fluoride with hydrofluoric acid containing uranium coming from nuclear fuel production line,which is also conducive to the minimization of radioactive waste and resource utilization.

Study on simulated aerosol suppression of UF₆ leakage

LIANG Dong, ZHANG Wenjun, XUE Dahai, GUO Lixiao, DENG Shaogang, WANG Yongxian, WU Mingliang, LiangYu

RADIATION PROTECTION. 2021, 41(3): 242-247.

Abstract ( 132 )

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Leakage of UF₆ can form droplet-type aerosols, causing chemical and radiological hazards to workers. Atomization suppression method to control those aerosols is commonly used. By adding NaCO₃ and other auxiliaries to the basic formula, a targeted aerosol inhibitor for UF₆ is obtained. Compressed air is used as the power and an ultrasonic atomizing nozzle is used as the main component of a fluid-powered ultrasonic atomizing device. SiCl₄ is used to simulate UF₆ leakage. The results show that the suppression effect of the aerosol inhibitor in 1 minute is equivalent to the effect of 12 hours natural sedimentation.

Practice and improvement of source term control in a PWR nuclear power plant

GUO Hang, JIN Weiyang

RADIATION PROTECTION. 2021, 41(3): 248-253.

Abstract ( 130 )

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According to the investigation of outage deposition source term of Unit 1 of Fuqing NPP, the surface activity, dose-rate contribution of ⁵⁸Co and ⁶⁰Co on the inner wall of primary loop pipeline and their variation with time are analyzed. Meanwhile, the formation, deposition and existence form of activated corrosion products in this PWR are introduced. By analyzing the influence of the main pump shutdown on the oxidation operation effect and the radiation level of the SG channel head during the outage 201, combined with the characteristics of the solubility change of the corrosion products in the acidic oxidation environment, a suggestion for improving the shutdown timing of the main pump to improve the oxidation operation effect is proposed. In addition, the influence on source term by the introduction of cobalt metal particles into the primary loop system caused by valve seal face maintenance is analyzed. It is suggested that strict measures should be taken to control the valve seal face maintenance process to reduce ⁵⁹Co entering into the primary loop system.

Study on formula improvement of cement solidification of boron concentrates from NPP

LUO Jinsong, YAN Xiaojun, CHEN Hongchun, WANG Zhao, GUO Xiaobin, GUO Xiliang

RADIATION PROTECTION. 2021, 41(3): 254-259.

Abstract ( 123 )

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A study on formula improvement for cement solidification of boron-containing concentrates and cement replacement was carried out. Based on the requirements of GB 14569.1—2011 “Performance requirements for low and intermediate level radioactive waste form-Cement solidification form”, cold tests were conducted with scales from laboratory, 200 L to 400 L, respectively, and the on-site solidifying process in nuclear power plants is simulated. Experimental results showed that the impact resistance, compressive strength, free liquid, freeze-thaw resistance, γ-irradiation resistance and immersion resistance of cement solidified samples meet the requirements of national standards, and the waste containment rate is increased from 46.99% to 57.63%. The cost per ton of solidifying waste materials is reduced by 69.29%. The recommended formula can be used to solidify real radioactive wastes.

Management status and response measures study of radiation accident emergency plan

ZHANG Yan, YANG Duanjie, QIAO Qingdang, ZHANG Shaojun

RADIATION PROTECTION. 2021, 41(3): 260-263.

Abstract ( 159 )

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In view of the current management situation of radiation accident emergency plan in China, this paper focuses on the problems existing in the plan management in terms of hierarchical positioning, management methods, preparation requirements, guidelines and standards, plan quality, etc, and puts forward relevant response measures and suggestions to provide reference for all regulators to further strengthen plan management.

Laminaria Japonica Polysaccharide attenuates radiation-induced submandibular gland injury in mice via promoting Sirt3/MnSOD expression

ZHANG Siqin, AO Pian, CHEN Shaoyong, CHAI Rong, WANG Shaojun, WEI Li, XU Yang, CHEN Chen

RADIATION PROTECTION. 2021, 41(3): 264-270.

Abstract ( 125 )

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The aim of this study is to investigate protective effect and the underlying mechanism of Laminaria Japonica Polysaccharide (LJP) on radiation-induced submandibular gland injury in mice. Eight-week-old female mice were randomly divided into four groups, including control group, LJP group, irradiation group, and irradiation plus LJP group. LJP (100 mg/kg/day) was intraperitoneally injected 3 days before irradiation and for consecutive 7 days (once daily).The mice from irradiation alone and irradiation plus LJP groups were exposed to a single dose of 15 Gy by using the ⁶⁰Co gamma rays. Histopathology and function of the submandibular glands (SMG) were detected on the 28th day post irradiation. The protein and mRNA expression of Sirt3 and MnSOD were respectively examined by real-time qPCR and immunohistochemical staining methods. Results showed that LJP injection significantly increased saliva flow rates in irradiated mice, improved the morphology and structure of SMG, and markedly up-regulated expressions of the Sirt3 and MnSOD. This suggests that LJP treatment could alleviate radiation-induced submandibular gland injury through activation of the Sirt3/MnSOD pathway.

Study on the problems of public communication regarding nuclear safety and its countermeasures

ZHAGNG Weihua, MENG Xianqing, YANG Anli, GAO Yuanxun, LIU Zhiqi, GUO Haifeng, DING Zhibo, FENG Jianping

RADIATION PROTECTION. 2021, 41(3): 271-275.

Abstract ( 133 )

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In order to safeguard public environmental rights and interests, improve nuclear and radiation safety supervision system, promote the healthy, stable and sustainable development of nuclear industry and build ecological civilization, relevant suggestions are put foreward, based on analyzing the difficulties and existing problems in the publicity work of nuclear safety. Suggestions such as to improve the public publicity system and mechanism, to integrate publicity resources, to balance the focus of publicity, to innovate publicity methods and approaches, to pay attention to experience feedback, with the aim to provide support for China's nuclear safety public communication work practice.

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