Sensitivity analysis of the groundwater flow at the Finnsjoen study site Yungbing, Bao; Thunvik, R [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Land and Water Resources] 54 ENVIRONMENTAL SCIENCES; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; GROUND WATER; WATER INFLUX; HYDRAULIC CONDUCTIVITY; SENSITIVITY ANALYSIS; EXPERIMENTAL DATA; GEOLOGIC FRACTURES; MAPS; PERMEABILITY; RADIOACTIVE WASTE DISPOSAL; SITE SURVEYS; UNDERGROUND DISPOSAL; 540250; 052002; SITE RESOURCE AND USE STUDIES; WASTE DISPOSAL AND STORAGE The object of the present investigation was to study, by means of sensitivity analysis, the impact on the solutions to flow calculations of some major fractures zones and the boundary conditions applied in the previous numerical modelling of the groundwater flow conditions at the Finnsjoen site. Sensitivity analysis is a useful complementary tool in groundwater flow modelling by making it possible to analyse qualitative as well as quantitative effects of various flow modelling concepts or model strategies on the flow solutions and to gain a general insight into the geohydraulic behaviour of the flow system studied. The sensitivity of the piezometric head and the sensitivity of the flux across an imaginary region of a hypothetical radioactive waste repository due to perturbations of the permeability in two major fracture zones were analysed. The influence of uncertainties in the prescribed piezometric head boundary conditions, applied in the previous groundwater flow modelling of the Finnsjoen study site, was studied. The uncertainties were due to a procedure used for transferring the boundary conditions from a `regional model` to a `local model` area. The study was performed by means of sensitivity analysis using an adjoint technique. The sensitivity of the piezometric heads as well as the Darcy flux, both point-wise and integrated over the imaginary repository region, was calculated. Similarly, the sensitivity at a discharge area of interest was calculated. The groundwater flow calculations are part of the SKB 91 performance assessment study of a generic high-level waste repository at the Finnsjoen site. Two different sensitivity methods, one called the direct method and the other the variational or the adjoint sensitivity method were applied. The numerical method for solving the flow equation as well as the sensitivity equation were based on the Galerkin finite element method. (au). Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden) OSTI; NTIS (US Sales Only); INIS Sweden 1991-09-01 English Technical Report Numerical Data Other Information: PBD: Sep 1991 Medium: X; Size: 102 p. https://doi.org/ ON: DE92623517 [] SKB-TR-91-42 Other: ON: DE92623517; TRN: SE9200015030432 SWDN; SCA: 540250; 052002; PA: AIX-23:030432; SN: 92000709409 2008-02-12 10135746