Performance Assessment and Modelling - Impacts of Extreme Climatic Scenarios on Groundwater Flow and Radionuclide Transport in the Overburden of a Nuclear Waste Repository in a Salt Dome

摘要

A generic, two-dimensional groundwater flow model is used to simulate the recent groundwater velocity fields and salt concentrations in the overburden of a potential nuclear waste repository in a salt dome. Thereupon, groundwater flow simulations are conducted for the three scenarios (i) constant climatic conditions, (ii) inundation of the area with sea water and (iii) permafrost conditions due a nearby inland ice-sheet. These possible extreme climate scenarios are deduced from the geological past of the area. Based on the stationary velocity fields, transport simulations for selected radionuclides were and are currently performed. The aim of this work is to determine the distribution and the contamination of groundwater and spring water after a potential incident within the repository leading to release of radioactively contaminated brine into the overburden. The programs d~(3)f (distributed density driven flow) and r3t (radionuclides, reaction, retardation, and transport) are used for the numerical modelling.