FEFTRA(TM) - Verification - Update 2013

FEFTRA is a finite element program package developed at VTT for the analyses of groundwater flow in Posiva's site evaluation programme that seeks a final repository for spent nuclear fuel in Finland. The code is capable of modelling steady-state or transient groundwater flow, solute transport and heat transfer as coupled or separate phenomena. Being a typical research tool used only by its developers, the FEFTRA code lacked long of a competent testing system and precise documentation of the verification of the code. In 2006 a project was launched, in which the objective was to reorganise all the material related to the existing verification cases and place them into the FEFTRA program path under the version-control system. The work also included development of a new testing system, which automatically calculates the selected cases, checks the new results against the old approved results and constructs a summary of the test run. All the existing cases were gathered together, checked and added into the new testing system. The documentation of each case was rewritten with the LATEXdocument preparation system and added into the testing system in a way that the whole test documentation (this report) could easily be generated in a postscript or pdf-format. The current report is the updated version of the verification report published in 2007. At the moment the report includes mainly the cases related to the testing of the primary result quantities (i.e. hydraulic head, pressure, salinity concentration, temperature). The selected cases, however, represent typical hydrological applications, in which the program package has been and will be employed in the Posiva’s site evaluation programme, i.e. the simulations of groundwater flow, solute transport and heat transfer as separate or coupled phenomena. The comparison of the FEFTRA results to the analytical, semianalytical and/or other numerical solutions proves the capability of FEFTRA to simulate such problems. The new verification cases of the updated report are related to the modelling of flow and salt transport in fractured media (including also cases for the discrete fracture network module recently incorporated into the code).