Sub-surface corrosion research on rock bolt system, perforated SS sheets and steel sets for the Yucca Mountain Repository — Quarterly technical report No. 14

This report shows the work done for this period in accordance to cooperative agreement of University of Nevada system for the Task 019 “Subsurface Corrosion Research on Rock Bolt System, Perforated SS Sheets and Steel Sets for the Yucca Mountain Repository”, the overall objective of which is to conduct corrosion research and predict the durability of rock-bolts and other underground metallic roof supports. We are performing oxidation tests using Thermogravimetric Analyzer (TGA), and Potentiodynamic and immersion tests to determine the corrosion rates of rock bolts. In this quarter specifically we have accomplished the following: Potentiodynamic tests were performed to determine corrosion rates (CR) of 4340 Steel in pure water and simulated seawater using sodium bicarbonate and/or sodium silicate as electrolyte(s) at 65C and 80C under deaerated conditions. Results are compiled for all the test performed now and previous quarter for these specific studies on additives that have indicated that silicate ions are beneficial to suppress carrion in both pure water as well as simulated sea water. A manuscript is in preparation for this particular topic. A manuscript is prepared for ht oxidation of rock bolts with data from micro-diffraction synchrotron studies to identify the layers of oxides as a function of temperature. More analyses of the synchrotron data obtained at the Advanced light source (ALS), Lawrence Berkeley National Laboratory are in progress to submit the manuscript on oxidation of rock bolts