Analysis of the influence of the multi-fracture water flow and heat transfer direction on the near-field temperature of high-level radioactive waste repository

The flow direction of fracture water and heat transfer directly affects the temperature field, water flow field, and nuclide migration in the near field of high-level radioactive waste repository. Compared with the general model of the same direction of fracture water flow and heat transfer in fractured rock mass, diversified directions of water flow and heat transfer in the disposal repository have been put forward in this paper. The influence of different flow directions of fracture water and heat transfer on the near field temperature of the repository was analyzed, which was significant to certain engineering application. Based on the conceptual model of fracture water flow and heat transfer, the influence of fracture water flow and heat transfer direction on the temperature of the repository was analyzed by using the 3 Dimension Distinct Element Code program. The results show that when the heat source release was about 0.896 month, the heat conduction between the fracture outlet water flow and the rock started to the couple, and the time required for the model to reach the steady state was about 43 months. When the flow direction of fracture water was the same, it was beneficial to the water flow to take away the heat in the near field of the repository. Conversely, this was not conducive for the water flow to take away the heat of the repository.