裂隙水流-传热对高放废物处置库近场温度影响的三维离散元分析

裂隙水流-传热是高放废物处置库行为的重要影响因素。为研究裂隙水流-传热对高放废物处置库近场温度的影响,采用3DEC离散元软件计算分析了完整岩体模型和裂隙岩体水流模型对处置库近场温度分布和演变的影响。计算分析表明:由于裂隙水流的吸热降温作用,裂隙岩体模型的废物罐表面膨润土温度低于完整岩体模型的废物罐表面膨润土温度,并缩短了达到稳态所需要的时间;裂隙水流上游区域废物罐表面膨润土温度显著低于裂隙水流下游区域废物罐表面膨润土温度;在设定条件下,裂隙岩体模型的废物罐表面膨润土最高温度约为完整岩体模型废物罐表面膨润土最高温度的75%,裂隙水流速度从0.2mm/s增大到0.5mm/s,废物罐表面膨润土最高温度降低约4%。

Three Dimensional Discrete Element Analysis of Influence of Fracture Water Flow and Heat Transfer on Evolution Temperature in Near Field of High Level Radioactive Waste Repository

Fracture water flow and heat transfer is an important influence factor on the behavior of high level radioactive waste repositories.The 3DEC discrete element software was used for analyzing an intact rock model without water flow and a fractured rock model with water flow.The influence characteristics of fracture water flow on the near field temperature distributions and evolutions were analyzed for a hypothetical high level radioactive waste repository.The calculations reveal that due to the endothermic effect of fracture water flow,the temperatures of the bentonite at the canisters surface obtained from the fractured rock model are lower than those from the intact rock model,and the time to reach steady state for the former is shorter;the temperatures of the bentonite at the canisters surface in the upstream are significantly lower than those in the downstream of the fractured rock model;under given conditions,the maximum temperature of the canisters surface bentonite for the fractured rock model is about 75％ of that for the intact rock model,and when the fracture water velocity is increased from 0.2 mm/s to 0.5 mm/s,the peak temperature of bentonite at the canisters surface is reduced by about 4 ％.