The SECO suite of codes for site Performance Assessment

Modeling for Performance Assessment of the Waste Isolation Pilot Plant (WIPP ) has led to development of the SECO suite of codes for groundwater flow, particle tracking, and transport. Algorithm and code developments include the following areas: facilitation of grid convergence tests in multiple domains; correct treatment of transmissivity factors for unconfined aquifers; efficient multigrid algorithms; a formulation of brine Darcy flow equations that uses freshwater head as the dependent able; boundary-fitted coordinates; temporal high order particle tracking; an efficient and accurate implicit Finite Volume TVD algorithm for radionuclide transport in (possibly) fractured porous media; accurate calculation of advection via a flux-based modified method of characteristics; and Quality Assurance procedures.