放射性核素在裂隙岩石中的迁移模型研究

本文描述了放射性核素在裂隙岩石中的单一介质和双重介质二维迁移模式,并用Galerkin有限元与算子分裂迎风—均衡格式相结合的方法求解了数学模型,取得了较为满意的结果。为了验证模型的正确性,分别用两种模型对济南岩溶区总硬度进行了数值模拟,计算结果与测定结果符合较好,说明模型是基本正确的。为了探讨模式对预测深部库核素迁移规律的适用性,对核素~(90)Sr和~(99)Tc的迁移进行了1000年的预测,结果与文献预测的核素分布规律相符合,说明模式对深部核素迁移是适用的。在上述两种模拟计算中,结果均没有发生数值波动和浓度出现负值的奇异现象,克服了用有限元法解弥散方程时浓度出现负值和数值波动问题,为建立高放废物库安全评价中的地圈子模式及进一步研究核素迁移模式提供了理论依据。

A MIGRATION MODEL OF RADIONUCLIDES IN FISSURED ROCK

This report presents a two-dimensional migration model of radionuclides in fissured rock. The mathematical model of radionuclide migration in dual porosity media consists of coupling four equations for migrations of groundwater flow and radionuclides in rock block and fissure field. The mathematical equations are solved by using Galerkin Finite Element method and Split Upwind Balance Scheme technique and satisfactory results are obtained. In order to verify the model and solving process,a numerical simulating calculation has been made by using the water gross hardness data of karst area in the western suburb of Jinan City, Shandong Province, China. The results are well in agreement with the measured values. For studying the suitability of the model of radionuclide migration in deep fissured rock, the calculations for ~(90)Sr and ~(99)Tc have been made. The results show that the computed distribution map are basically in agreement with that predicted in references.