Table of Content

15 February 2019 Volume 39 Issue 1

  

Preliminary Design of Anti-floating Device in Cement Immobilization of Radioactive Waste

Wang Zhanpeng, Yu Bo, Xue Yanjun, Lin Tongxu, Xu Kun

RADIATION PROTECTION BULLETIN. 2019, 39(1):  1-6. 

Abstract ( 94 )   PDF (1627KB) ( 209 )  

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Directed at the waste cake floating problem in the process of cement immobilization of radioactive waste in a nuclearpower plant, an anti-floating device was designed. And a mathematical model wasalso established to analyze the relationship between the length of cake and theloading ratio of the repackaging drum. With the current process data as input,the calculation provides a basis for selection of 320 L drum, with different block slice length, for repackaging. The safe loading interval of such a kind of repackaging drum is then calculated, which resulted in a Table of Optimized Safe Loading Interval for Waste Cakes. The optimization of this loading operation canbe theoretically based on.

Simulation Calculation of Internal Dose Rate in EA FGD

Wang Qiyun, Li Jianjun, Li Shenghua

RADIATION PROTECTION BULLETIN. 2019, 39(1):  7-10. 

Abstract ( 93 )   PDF (956KB) ( 117 )  

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In order to verify the feasibility ofMCNP for calculating the internal dose rate of an electron beam ammonia desulfurization vessel, the principle of “pinhole imaging" is employed to simulate an electron accelerator with energy of 0.57 MeV. The dose rate is then calculated, and compared with experimental measurements in the literature and the simulationvalues with the EGS4 program. It shows that the MCNP program calculation resultsat 25.7% error are consistent with those from the EGS4 program simulation.

Dose Rate Analysis Algorithm and Measurement outsideAccelerator Primary Shielding Area

Feng Zechen, Ma Yongzhong, Sun Yaru, Zhu Weijie, Wang Shijin, Lou Yun

RADIATION PROTECTION BULLETIN. 2019, 39(1):  11-13. 

Abstract ( 157 )   PDF (647KB) ( 108 )  

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Shielding is an important measure to ensure that the dose rate and dose outside an accelerator room meet the control objectives. The optimization design of shield thickness generally uses some analytical algorithms and its reliability needs to be verified. Outside the primary shield of an accelerator, 10 sites and another one of flat filter free high doserate mode, are selected to perform dose rate calculation, using analytical algorithms in IAEA Report No.47 and GBZ/T 201.2. The outcomes are then compared withthe measured results. It shows that calculated values with the IAEA approach are higher than those with GBZ/T 201.2 parameters employed, with the latter much closer to measurements. However, there are some individual sites with a measured,higher than calculated dose rate, which's maybe due to insufficient concrete thickness. The analytical algorithm of GBZ/T 201.2 can reasonably estimate the dose rate outside the main shielding area. During the construction process, the project quality should be strictly controlled to ensure that the concrete density and construction thickness are consistent with the design.

An Industrial Flaw Detection induced Radiation Event and its Feedback

Tang zhen, Zhang qian, Ye Haifeng, Shen song, Hu Caiping, Xu Zhengqiang, Wu Jianhua, Ying Hongmei, Lin Qichun, Wang Yuangao

RADIATION PROTECTION BULLETIN. 2019, 39(1):  14-17. 

Abstract ( 314 )   PDF (1059KB) ( 227 )  

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A radiation event in an operation of industrial flaw detection in Ningbo, Zhejiang Province in 2017, is presented, along with treatment of it. Based on the survey and a conservative dose estimation,exposure dose of non-inspective workers on site was approximately 29.54 μSv,less than the annual management limit of 0.25 mSv, and also the public annual dose limit of 1 mSv. The management department accordingly identified the mis-irradiation of this time as a radiation event and provided regulatory advice via feedback.

Study on the Rule of Error Interval of Radiation Monitoring System in NPPs

Li jing

RADIATION PROTECTION BULLETIN. 2019, 39(1):  18-20. 

Abstract ( 102 )   PDF (804KB) ( 88 )  

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The radiation monitoring system is onemain means of radioactivity monitoring in NPPs. Its operational status has always been highly valued by national regulatory authorities, especially relevant human events. Through practical case analysis, the common problems among these cases are studied. It’s found that the probability of occurrence of the error interval is obviously related to the nature of the work of the operator and the management attribution. And the equipment which is easy to be incorrect operated also has clear features. Based on these correlations and characteristics analysis,suggestions for improving the reliability of the operation of the radiation monitoring system are proposed.

Colletive Dose Analysis and Optimization Improvement for General Service Personnel during the First Overhaul of Unit 1 in some NPP

Li Tengfei

RADIATION PROTECTION BULLETIN. 2019, 39(1):  21-26. 

Abstract ( 137 )   PDF (1501KB) ( 183 )  

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The colletive dose distribution of general service personnel in different positions during the first overhaul of Unit1 in some NPP is presented. The sources and causes of dose are analyzed. Some improvement measures for optimization are proposed correspondingly, which's then been applied to the first overhaul of Unit 2. The implementation of these measures has been verified by overhaul personnel dose comparison of both units. And thegoal of reducing personnel dose is ultimately achieved.

Activity Concentration of ¹³⁷Cs in Seawater fromCoastal Areas of Guangdong, China, in the year of 1993-2017

Zhang Yanjin, Deng Fei, Feng Yingsi, Li Qiaoqin

RADIATION PROTECTION BULLETIN. 2019, 39(1):  27-32. 

Abstract ( 125 )   PDF (1706KB) ( 57 )  

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The ¹³⁷Cs activity concentration in seawater around Daya Bay, Yangjiang and Taishan NPPs, and from other coastal areas in Guangdong, is presented. And the impact of nuclear power liquid effluent discharge on seawater in the nearby area is analyzed. For Daya Bay Nuclear Power Station, the ¹³⁷Cs activity concentration in seawater was significantly higher than the background level due to abnormal emissions in the early days, which was then returned to the background level. The concentration of ¹³⁷Cs in the seawater around Yangjiang Nuclear Power Station varies from0.49 to 4.77 Bq/m³. The concentration of ¹³⁷Cs activity in seawateraround Taishan Nuclear Power Station ranged from <0.11 to 2.21 Bq/m³. The activity concentration of ¹³⁷Cs in seawater from other areas ranges from0.62 to 2.52 Bq/m³. The results show that the concentration of ¹³⁷Csin seawater in coastal waters of Guangdong fluctuates within the background level.

⁹⁰Sr Radioactivity Levels in Surface Water and Drinking Water around Yangjiang NPP, in the year of 2009-2011 and 2015-2018

Ou Yangjun, Zhu Shenhe

RADIATION PROTECTION BULLETIN. 2019, 39(1):  33-37. 

Abstract ( 136 )   PDF (1114KB) ( 77 )  

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The radioactivity level of ⁹⁰Sr in surface water and drinking water of the surrounding environment before and after the operation of Yangjiang Nuclear Power Plant (YJNPP)was investigated.It was then compared with those for control points. The results show that the concentration of ⁹⁰Sr is generally at the same level before and after NPP operation, and comparable to those of control points.