[en] The Wellenberg site in the Canton of Nidwalden, Central Switzerland, is being investigated as potential location for the disposal of radioactive waste. Five deep boreholes were drilled at the site. This report describes hydraulic packer testing conducted in three of these boreholes between June 1990 and December 1991. A total of sixty-three single and double packer tests were conducted and analyzed. The principal objectives of the tests were the measurement of the formation equivalent freshwater head and the hydraulic conductivity. Fourteen of the tests were designed and conducted principally for groundwater sampling. The tests were designed, conducted and interpreted taking account of the anticipated presence of methane gas within the rock at the site. The equipment used for the testing included a Baker/Lynes Hydrological Test Tool. A Moyno pump was used as the principal downhole production system, and Grundfos and Shimadzu pumps for injection. Liquid-gas separation equipment was used for withdrawal tests because of the anticipated presence of methane. A flow control and metering system was provided, and this was linked to a computer-based data acquisition system. Data analyses were performed using the standard pressure transient interpretation software Interpret and Interpret/2. Special attention was paid to the application of constant rate analysis for the interpretation of constant pressure events and of discontinuous events such as slug and pulse tests. The low hydraulic conductivity conditions found at the site can result in ambiguities in test interpretation. In order to estimate the range of possible errors, sensitivity analyses were conducted for selected test sequences. These investigated the influence on the analysis results of borehole pressure history and of the input parameters. (author) figs., tabs., 38 refs

[en] Hydraulic packer testing is currently the most commonly used method to determine the characteristics of fluid flow in geologic formations. Constant rate tests and slug tests are the most commonly used test methods. The application of slug test deconvolution was extended to gas-water systems. The approach used is to compare injection and withdrawal events by means of Test Type Comparison Curves. Is is shown that the method described is sensitive to the gas saturation conditions of the tested formation. Finally, the method is applied to three field examples. (R.P.)

[en] Boreholes SB4a/vertical (SB4a/v) and SB4a/slanted (SB4a/s) are the sixth and seventh deep investigation boreholes drilled from a single drill-site at Wellenberg as part of the Phase II investigation programme of the Wellenberg site (NAGRA, 1994). This site is under consideration as a potential location for a possible repository for low- and intermediate-level radioactive waste. This report presents the results and describes the methods applied in the pressure transient testing of the vertical and the slanted borehole SB4a. A total of twenty three packer tests were successfully conducted in the vertical and twenty four in the slanted borehole. A primary objective of the tests was to characterise the flow properties of the formation under single and two-phase flow conditions. Of equal importance was the determination of the head distribution in the potential repository area. In general, the tests were designed and conducted in a way which allowed a flow model to be derived that accurately reflects the characteristics of the formation. Based on this flow model the effective conductivities and the heads were determined. The downhole equipment used included single and double packer set-ups as well as special tools designed for gas injection testing and for downhole sampling. Two levels of test interpretation were applied; standard and detailed test analysis. These levels were applied to both single and dual phase tests, and to gas threshold pressure tests. Test data were analysed in two steps. The first step involved using the analytical interpretation software FLowDIM and INTERPRET/2. State of the art diagnostic methods as well as careful evaluation of rate sequence and input parameters constituted the basis for an iterative analysis sequence. Based on these analysis results, consistency checks and analyses using alternative interpretation software (MULTIFIT and GTFM) were performed. For cases of two phase flow the TOUGH / ITOUGH2 codes were applied. Standard analyses were performed for all forty seven tests. Twelve tests were also analysed at a detailed level. Interpreted hydraulic conductivities for both boreholes range from 10^-13 m/s to 10^-6 m/s. The head distribution confirmed the results obtained from other investigation boreholes drilled at this site. The heads were hydrostatic to slightly artesian in the upper parts of the boreholes, to about 600 m below ground level. In the lower part of the boreholes head conditions well below hydrostatic were encountered. The lowest head measured was over 600 m below ground level. The occurrence of small amount of gas in the Palfris formation and surrounding formations was again confirmed. The zones where gas was encountered were approximately between 150 m and 520 m below ground level in the vertical borehole, and between 120 m and 390 m in the slanted borehole. (authors)

[en] This paper presents the application of so-called gas threshold pressure tests (GTPT) to assess the behavior and two-phase flow properties of clay-rich sedimentary rocks under investigation for disposal of high-level radioactive (HLW) and spent fuel. (authors)

[en] The author report a study based on 26 patients in good general status and suffering from unique hepato-carcinoma with a maximum diameter of less than 10 cm treated by a unique chemo-embolization session followed by a conformational radiotherapy. The results are discussed in terms of tumour response, of relapse occurrence, of survival and of toxicity. Short communication

[en] Due to its increasing incidence and a grim prognosis, primary liver cancer remains a diagnostic and therapeutic challenge. For small localized tumors, surgical resection and liver transplantation are standard treatments with a curative-intent. Therapeutic options for locally advanced or metastatic diseases are limited. Globally, surgery fits less than 20% of patients. Early detection in high-risk patients and prevention of risk factors remain the key points in the standard care. External radiotherapy is a non invasive treatment with encouraging results for non operable patients. Emerging stereotactic radiotherapy yields high rates of local control without compromising toxicity. Tumors with bad prognostic factors could be cured with this approach. (authors)

[en] This session gathers 6 articles dealing with: gas migration through bentonite/sand: Lessons learned from the GMT in-situ test (T. Shimura, S. Vomvoris, G.W. Lanyon, P. Marschall, K. Ando, S. Yamamoto, H. Asano); the modeling approaches of two-phase flow phenomena associated with corrosion of SF/HLW canisters in a proposed repository in Opalinus clay, Switzerland (R. Senger, T. Xu, P. Marschall, S. Finsterle); the approaches for modelling gas transport in clay formations based on improved Darcy and non-Darcy flow concepts (H. Alkan, W. Mueller); deriving large scale hydraulic behaviour from borehole pressure history data (C. Enachescu, J. Delay, M. Cruchaudet, R. de la Vaissiere); the interpretation of interstitial pressures in clay media: Application to the Callovo-Oxfordian (P. Rousseau-Gueutin, J. Goncalves, M. Cruchaudet, S. Altmann, V. de Greef, S. Violette); and the porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the states of water (G. Montavon, E. Alhajji, D. Lebotlan, Z. Guo, C. Tournassat, B. Grambow)

[en] This session gathers 30 articles (posters) dealing with: the three Dimensional analyses of combined gas, heat and nuclide transport in a repository considering coupled thermo-hydro geomechanical processes; the experimental study on the thermo-hydro-mechanical behaviour of boom clay; hydraulic in-situ measurements in the Opalinus clay in the frame of a heater test performed at the Mont Terri URL; the hydro-mechanical behaviour of natural boom clay in controlled-suction tests; a constitutive approach to address the thermal and hydric impacts in the concept of deep radioactive waste repositories; the numerical analysis on stability of boom clay tunnel by shield construction; a thermo-hydro-mechanical model for clay in unsaturated conditions; the 3D modelling of TER experiment accounting for fully anisotropic thermo-poro-elastic behaviour; the hydro-mechanical modeling of shaft excavation in Meuse/Haute-Marne laboratory; the modelling of drying damage in engineered and natural clay barriers for nuclear waste disposal; the elasto-viscoplastic behaviour of Meuse/Haute-Marne argillite: laboratory tests and modelling; the long-term behaviour of a lime treated soil under percolation conditions; the stress redistribution and hydro-mechanical effects due to excavation and drilling operations in TER experiment; a thermodynamic model on swelling of bentonite buffer and backfill materials; the 3D analysis of a heating test in the Opalinus clay; the THM analysis of a 'mock-up' laboratory experiment using a double-structure expansive model; the measurement of the effect of re-confinement on rock properties around a slot; a laboratory Study of desaturation - re-saturation effects on a clay-stone; the deformation induced by dissolution of salts in porous media; the bentonite swelling pressure in pure water and saline solutions; the mineralogy and sealing properties of various bentonites and smectite-rich clay materials; the evaluation of the geochemical processes occurring in the Opalinus clay formation subjected to a ventilation test; a Soil structure considerations in description of compacted and natural clay behaviour; the hydro-mechanical behaviour of Tunisian clayey soil used as discharge site of acidic waste; the Consolidation and rebound properties of Opalinus clay: a long-term, fully-drained test; the multidimensional modeling of a poro-elastic medium: identification of the behaviour of a clay formation from a stochastic representation of piezometric fluctuations; various approaches for the comprehension of the time-dependent behaviour of Callovo-Oxfordian argilite; a new approach of estimating the influence of drilling mud on the borehole pressure history; the thermo-chemical-hydro-mechanical modelling: contributions to the assessment of the long term behaviour of a nuclear waste disposal in a deep clay formation; and the impact of thermal load on the far field and galleries of a repository