γ-radiation field reconstruction method basedon source activity inversion calculations
LI Hua1, ZHAO Yuan1, CAO Qinjian1, HE Liang1,2, LI Junli2, LIU Liye1
1. Radiation Dosimetry Laboratory, Department of Health Physics, China Institute for Radiation Protection, Taiyuan 030006, China; 2. Key Laboratory of Particle&Radiation Imaging ofMinistry of Education, Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Abstract：Three-dimensional radiation fields must be known to predict the distribution of real external exposures in nuclear facilities. Such data fields provide the basis for establishing effective shielding measures and determining reasonable operating plans at nuclear facilities. Three-dimensional gamma radiation fields were reconstructed using point-kernel integral theory and a source activity inversion algorithm using the least squares method and a Gauss-Seidel iterative algorithm. The results were then used to study the influences of the dose measurement positions on the source inversion results. The reconstruction method was verified using measured data from a nuclear power plant. The results show about 10% difference between the reconstructed gamma radiation field data and the measured data which is sufficient for radiation protection studies of nuclear facilities and for optimizing radiation protection procedures.
[1] OHGA Y, FUKUDA M, SHIBATA K, et al. A system for the calculation and visualization of radiation field for maintenance support in nuclear power plants[J]. Radiation Protection Dosimetry, 2005, 116(1-4):592-596. [2] MÓL A C A, PEREIRA C M N A, FREITAS V G G, et al. Radiation dose rate map interpolation in nuclear plants using neural networks and virtual reality techniques[J]. Annals of Nuclear Energy, 2011, 38(2-3):705-712. [3] RÓDENAS J, ZARZA I, BURGOS M C, et al. Developing a virtual reality application for training nuclear power plant operators:Setting up a database containing dose rates in the refuelling plant[J]. Radiation Protection Dosimetry, 2004, 111(2):173-180. [4] JEONG K S, CHOI B S, MOON J K, et al. Real-time assessment of exposure dose to workers in radiological environments during decommissioning of nuclear facilities[J]. Annals of Nuclear Energy, 2014, 73:441-445. [5] DA SILVA M H, DO ESPÍRITO SANTO A C, MARINS E R, el al. Using virtual reality to support the physical security of nuclear facilities[J]. Progress in Nuclear Energy, 2015, 78:19-24. [6] SAUNDERS P. Exposure reduction through optimized planning and scheduling:Guidance on incorporating ALARA concepts[R]. Palo Alto, USA:Electric Power Research Institute (EPRI), 2005. [7] VERMEERSCH F. ALARA pre-job studies using the VISIPLAN 3D ALARA planning tool[J]. Radiation Protection Dosimetry, 2005, 115(1-4):294-297. [8] VERMEERSCH F. VISIPLAN 4.03D ALARA planning tool user's manual[Z]. Antwerp, Belgium:SCK·CEN, 2006. [9] SAUNDERS P, RAHON T, QUINN D, et al. Demonstration of advanced 3D ALARA planning prototypes for dose reduction[R]. Palo Alto, USA:EPRI, 2012. [10] 李春槐. 点核积分程序研制和发展[J]. 核动力工程, 2001, 22(1):19-21, 41. LI C H. Development and improvement in point-kernel integral computer code[J]. Nuclear Power Engineering, 2001, 22(1):19-21, 41. (in Chinese) [11] 李华, 赵原, 刘立业, 等. 基于MCNP对γ射线吸收剂量累积因子的计算与研究[J]. 辐射防护, 2017, 37(3):161-168. LI H, ZHAO Y, LIU L Y, et al. Research on gamma ray buildup factor for energy absorption based on MCNP[J]. Radiation Protection, 2017, 37(3):161-168. (in Chinese) [12] 李华, 赵原, 刘立业, 等. 介质尺寸对水中γ射线吸收剂量累积因子的影响[J]. 清华大学学报(自然科学版), 2017, 57(5):525-529. LI H, ZHAO Y, LIU L Y, et al. Effect of medium size on the γ-ray buildup factor for energy absorption in water[J]. Journal of Tsinghua University (Science and Technology), 2017, 57(5):525-529. (in Chinese) [13] 刘立业, 曹勤剑, 熊万春, 等. 基于高纯锗探测器的核电厂一回路系统辐射源项就地γ谱测量[J]. 辐射防护, 2015, 35(5):257-261. LIU L Y, CAO Q Q, XIONG W C, et al. In-situ gamma-spectrometry measurement of radiological source term for primary system of NPPs based on HPGe detector[J]. Radiation Protection, 2015, 35(5):257-261. (in Chinese) [14] 刘立业, 马吉增, 张斌全, 等. Monte Carlo方法用于就地γ辐射源项调查与剂量评估[J]. 清华大学学报(自然科学版), 2007, 47(S1):991-995. LIU L Y, MA J Z, ZHANG B Q, et al. Monte Carlo method for in situ gamma radiological characterization and dose estimation[J]. Journal of Tsinghua University (Science and Technology), 2007, 47(S1):991-995. (in Chinese)
2020, Vol. 60 
