Validation of reactive transport codes: a benchmark study for the migration of uranyl through a quartz column

摘要: Full text of publication follows: There is an increasing interest in reactive transport in various domains of science. For example, the release of radionuclides from a nuclear waste repository is best modeled using a reactive transport code. Such a code ideally handles complex flow patterns and treats chemical reaction mechanisms such as surface complexation down to the molecular level. The present study attempts a comparison of different reactive transport codes. This appears necessary since the quality of available codes with their necessarily complex numerical schemes can usually not be judged otherwise. The use of such codes for performance assessment should therefore be critically assessed. To build confidence in the codes, the proposed system (migration of uranyl containing solution through a column of quartz) is predicted with a range of available codes. The surface complexation model used to describe the interaction of uranyl with the quartz surface is fitted to experimental batch adsorption data. This model is then applied to the transport of a solution of a given uranyl concentration with a given flow velocity through a quartz column with pre-defined hydrodynamic properties. The computations are performed with different reactive transport codes (HBGC3D, CRUNCH, HYTEC, RETRASO, ECOSAT) and the respective calculated breakthrough curves are compared. With the proposed benchmark system the complexity of the system can be successively increased (e.g. from 1D to 2D flow) and potential problems within the codes can be identified. (authors)