RADIATION PROTECTION

Performance of OSL dosimeter and analysis of uncertainty in measurement

WANG Lijiao, XIAO Wenhui, LU Ying, LU Zheng, LIU Xiaolin, HUANG Yan, CHEN Ling

RADIATION PROTECTION. 2018, 38(5): 353-358.

Abstract ( 158 )

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OSL dosimeter is a kind of passive intergrating personal dosimeter used in the monitoring of occupational external exposure dose. Though at present, OSL dosimeter is not used as widely as TLD dosimeter possibly due to the lack of a comprehensive study on OSL dosimeter’s performance and property,OSL dosimeter will get a wide application in our country in the future because of its advantages such as repeatable measurements, good environmental stability, long service life and slow signal decay. In this paper, OSL dosimeter’s minimum detectable level, angle of incidence response, energy response, and linearity response have been reviewed from the experience of using OSL dosimeters in monitoring work. Based on the experimental results, the uncertainty in measurement has been analyzed. The results show that OSL dosimeter’s MDL in one month is 0.04 mSv. The errors caused by angle of incidence response, energy response, linearity response are 1%, -14%, and -4%, respectively. With a 95% confidence interval, relative expanded uncertainty is 11.4%.

ESR response of window glass to γ radiation

LIU Yulian, ZHAO Zhixin, RUAN Shuzhou, SU Kaijun, ZHANG Wenyi, JIAO Ling

RADIATION PROTECTION. 2018, 38(5): 359-365.

Abstract ( 115 )

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The factors affecting ESR dosimetry of window glass were explored for better application in personal dose estimation and accident grade determination. The effect of sample processing on the background signal and the radiation signal was studied by grinding the window glass into different particle sizes. The window glass samples were given different dose of radiation, and were stored under different conditions. The effects of temperature, light, and time on the ESR signal were observed. The dose response curves and the minimum detection doses of window glass from different manufacturers were compared. The results show that the sample processing has no obvious effect on the radiation signal, but it will produce mechanical signal; the higher the temperature, the more unstable the radiation signal. High-temperature heating (≥200 ℃, ≥5 min) can decay the ESR radiation signal to background level. The results of samples(transparent bag-lamplight storage,and black bag storage) are approximately the same: after 11 hours, the signal intensity reduced about 9%; after 150 hours, the signal intensity reduced about 18%.Signal decayed 17% after 11 hours and decayed 38% after 150 hours for samples with transparent bag-sunlight storage. The samples under the three storage conditions all reached to a stable state after about 150 hours; the ESR signal of the window glass sample at g=2.0057 is linearly related to the absorbed dose, and the linear correlation coefficients varied with different manufacturers. The minimum detectable dose is 4-5 Gy. Therefore, in the practice of window glass as dosimeter, a reasonable dose assessment procedure should be set up for more accurate results.

Research on the relationship between air change rate and indoor radon activity concentration in newly-built house in Guangzhou

LIU Shubo, MEI Aihua

RADIATION PROTECTION. 2018, 38(5): 366-370.

Abstract ( 97 )

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Three sets of newly-built house in Guangzhou were selected to view the relationship between indoor radon activity concentrations and the air change rate. Indoor radon activity concentrations and the air change rate were measured when rooms were in the following three conditions: fully enclosed; air hole opened; both the air hole and the window opened. The indoor radon activity concentrations in the rooms of the same floor and in the rooms of the same side but different floors were measured using activated carbon box method. The results showed that, inside the bedroom of a totally enclosed new house in Guangzhou, the air change rate was low (less than 0.2 h^-1), and the indoor radon activity concentration was high (more than 200 Bq/m³). At the air change rate of around 0.5 h^-1, the indoor radon activity concentration dropped below 200 Bq/m³; and a significant reduction in the radon activity concentration below 100 Bq/m³ was found at the air change rate above 1.0 h^-1. Indoor radon activity concentrations decreased vertically with the increase of floor level. No obvious horizontal trend on indoor radon activity concentration was found for the same floor.

Analysis on time difference in dose comparison of TLD and EPD

HOU Bingjun

RADIATION PROTECTION. 2018, 38(5): 372-375.

Abstract ( 141 )

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To solve the problem which exists in the regular comparison between thermoluminescent dosimeter(TLD) and electron dosimeter(EPD) during the operation of Tianwan nuclear power station No.1 unit and No.2 unit, the abnormal dose distribution caused by difference timing for replacing dosimeter was analyzed. A set of technical scheme is designed, including data acquisition, data storage, data processing and data output. Deviation of TLD and EPD in the actual period of individual monitoring and the time difference problem in the regular dosimetry comparison were solved.

Study on the standards system of radioactive effluent monitoring and radiation environmental monitoring for nuclear power plants in China

HUANG Yanjun, SHANGGUAN Zhihong, HUANG Donghui, YANG Litao, CHEN Chaofeng, WU Liangsheng, ZENG Fan

RADIATION PROTECTION. 2018, 38(5): 377-387.

Abstract ( 111 )

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In order to meet the supervision and management requirements of environmental radiation safety of nuclear power plants and guide the development of effluent monitoring and radiation environment monitoring velopment of nuclear power plants to adapt the new status of a rapid development of nuclear power in China, the present monitoring standard system needs to be reviwed and improved. The general requirements of effluent and environmental radiation monitoring for nuclear power plants are analyzed and some suggestions on revising or developing on present standards are given in this article. It will provide a reference for strengthening and perfecting the standard system of effluent and environmental radiation monitoring for nuclear power plants in China.

A decision support system based on OILs optimized for multi-unit accident

CHEN Qian, HUANG Yichao, TAO Naigui, SUN Xuefeng, LIU Zhanyang

RADIATION PROTECTION. 2018, 38(5): 389-395.

Abstract ( 95 )

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OILs are measurable radiation parameters which are related to the generic intervention level of the specific action for public protection. OILs can be used to provide recommendations on emergency protective actions through comparison with environmental monitoring data. After Fukushima nuclear accident, emergency preparedness and response of nuclear power plants in China focuses on the issues of multi-unit accident. Based on the methods of calculation and revision of OILs suggested by IAEA, methods of calculation OILs for multi-unit accident were established, and the corresponding decision support system was also designed and implemented. The system provided a complete process for use of OILs including the function of data management, data query, calculation, revision and decision on protective actions, which can be used for both single-reactor and multi-reactor accident. The system has been applied in Qinshan, Ningde, Sanmen, Taishan and Yangjiang NPPs in China.

Scenario design for nuclear accident emergency exercise based on PSA

XU Chunsong, BAI Zhiqiang, LI Bing

RADIATION PROTECTION. 2018, 38(5): 396-401.

Abstract ( 101 )

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Besides the review of relevant operation events/accidents, the nonconformities happened in plant construction, the screening of local natural disasters and external events, and the reference of incident/accidents occurred in other nuclear plants,the events/accidents with high representation and pertinence were preliminarily chosen based on the conclusion of the probabilistic safety analysis (PSA) of the Changjiang nuclear power plant. Based on the studies above, several complete accident sequences were formed. Small accident scenarios were compiled, which could be inserted to the complete accident sequences at any time with no interruption. Examples of scenarios and suggestions were given to improve the rationality and pertinence of the design of accident scenario.

Analysis of initial events of uranium purification and conversion facility

XU Xiaoxiao, ZHANG Jiangang, WANG Renze, YANG Yapeng, FENG Zongyang, JIA Linsheng, WANG Ning

RADIATION PROTECTION. 2018, 38(5): 402-407.

Abstract ( 82 )

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The initial events analysis is the basis of probabilistic safety analysis. Quantitative evaluation of the initial events is the precondition for probabilistic safety analysis to obtain quantitative risk results. Combination of engineering evaluation and deductive analysis is used to identify the initial events of typical uranium purification and conversion facilities. According to the similarities and differences of facility safety protection measures, the initial events are categorized into five groups, and the UF₆ leakage is the main concern in uranium purification and conversion facility. Event tree for accident sequence analysis was used to obtain UF₆ leakage events sequence and the corresponding frequency.

Estimation of graphite dust production in core of high temperature gas cooled reactor

LIANG Yu, GUO Lixiao, DENG Shaogang, LIANG Dong, WANG Yongxian, LI Ning

RADIATION PROTECTION. 2018, 38(5): 409-413.

Abstract ( 98 )

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Key conditions for wear rate of graphite balls are load and temperature in the core of a spherical bed type high temperature gas cooled reactor. In its previous study, China Institute for Radiation Protection obtained the relationship between wear rate of graphite balls and load. In this paper, further study on the effect of temperature upon wear rate of graphite balls is implemented and the produced amounts of graphite dust are calculated. Fitting the relationship of loading and temperature on wear rate of graphite balls, as well as the distribution of load and temperature of fuel elements in HTR-PM,the produced graphite dust was calculated as about 14.01 g/d (5.1 kg/a).

Chemical optimization and radiation sources control of primary loop water in Tianwan Nuclear Power Plant

WANG Haiping, YU Miao, REN Lijuan

RADIATION PROTECTION. 2018, 38(5): 415-420.

Abstract ( 100 )

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Among many factors influencing radiation fields at primary loop of nuclear power plants, two main aspects are the materials of system equipment and the chemical parameters of primary loop water. The effects of dissolution H₂, boron potassium coordination curve control, technology for Zn injection, and reactor shutdown oxidation operation on radiation sources are discussed in this paper. Relevant advices are provided.

Safe test experience on radioactive material transport packages

ZHANG Jiangang, LI Guoqiang, SUN Hongchao, ZHUANG Dajie, SUN Shutang, MENG Dongyuan

RADIATION PROTECTION. 2018, 38(5): 422-427.

Abstract ( 104 )

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The transport safety of radioactive material is supervised with graded approach in China. Testing is the most direct way to verify the safety performance of transport containers. The testing requirements for transport container and the detecting methods are comprehensively described in this paper. The experience of container testing is reviewed.

Protective effect of hydrogen rich water on acute hematological damage in Beagle dogs exposed to ⁶⁰Co

QIN Xiujun, SUN Ge, YUE Juan, HUANG Liqun, LI Weibin, YIN Jingjing, LI Jianguo

RADIATION PROTECTION. 2018, 38(5): 428-432.

Abstract ( 84 )

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The protective effect of hydrogen rich water on the acute hematological damage of Beagle dogs exposed to ⁶⁰Co γ ray irradiation was studied. Male Beagle dogs were randomly divided into control group, irradiation group and hydrogen rich water intervention group. After a single irradiation of 2.0 Gy gamma ray, the peripheral blood of the animals was collected on the 2^nd and the 7^th day. The indexes of hematology, antioxidation, lymphocyte apoptosis rate and 8-OHdG were detected. The results showed that on the 7^th day after irradiation, RBC, HGB and HCT of the hydrogen rich water group were higher than those of the irradiation group (p<0.01, p<0.05, p<0.05); on the 2^nd day and the 7^th day after irradiation, T-AOC of the hydrogen rich water group was higher than that of the irradiated group (p<0.01, p<0.05), and MDA was lower than that of the irradiation group (p<0.01, p<0.05); on the 2^nd day and the 7^th day after irradiation, lymphocyte apoptosis rate of the hydrogen rich water group was lower than that of the irradiation group (p<0.05, p<0.01); on the 7^th day after exposure, the concentration of 8-OHdG in hydrogen rich water group was lower than that of the irradiation group (p<0.05). These results indicate that hydrogen rich water can improve the blood index of Beagle dogs by the mechanism of anti oxidative stress and anti apoptosis.

Discussion on experience in clinical treatment of the case exposed to ¹⁹²Ir in the radiation accident in Nanjing

WANG Youyou, LIU Yulong, BIAN Huahui, CHEN Weibo, DAI Hong, FENG Junchao, QIU Mengyue

RADIATION PROTECTION. 2018, 38(5): 434-438.

Abstract ( 131 )

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From the review of a a case suffered from mild bone marrow radiation sickness combined with IV°acute radiation-induced skin injury in a major radiological accident that occurred in Nanjing, the treatment scheme and management pattern are summarized. Focusing on dose estimation, flap transplantation, application of ectomesenchymal stem cells, infection control and psychological counseling on patients, the treatment technology for similar radiation injury has been explored and discussed. It provides information and accumulates experience for medicine emergency of nuclear and radiation accident.

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