Sellafield geological investigations for deep radioactive waste repository. Deep Borehole No. 16. Factual Report. App. D1

This Factual Report presents an account of all the Discrete Extraction Tests carried out in Deep Borehole 16. The text of this report outlines in general terms the test equipment, test methodology and data produced. Full details of each DET are given in Appendices. Appendices A to E gives the specific details each DET presented in data tables and figures. Appendix F contains data disks of gauge data. The objectives of a DET may be twofold: (i) an initial part to determine the environmental pressure and hydraulic conductivity of the test section; (ii) a second part to produce relatively uncontaminated formation fluid for geochemical analysis. Depending on the results obtained during the whole testing programme a test may be modified to omit or adjust the two parts described above. All fluids introduced into the borehole during drilling and testing are tracered with target concentrations of 100 ± 4 ppm potassium iodide and 3 ± 0.15 ppm sodium fluorescein, and the contamination levels are monitored throughout the drilling and testing programme. During a DET when fluid is produced at surface the contamination of the production fluid is assessed regularly to adjust and control the fluid sampling programme. (author)