Laboratory Testing of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal FacilityReport as inadecuate


Laboratory Testing of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal Facility


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Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow G1 1XJ, UK





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Academic Editor: Jesus Martinez-Frias

Abstract Geological disposal facilities for radioactive waste pose significant challenges for robust monitoring of environmental conditions within the engineered barriers that surround the waste canister. Temperatures are elevated, due to the presence of heat generating waste, relative humidity varies from 20% to 100%, and swelling pressures within the bentonite barrier can typically be 2–10 MPa. Here, we test the robustness of a bespoke design MEMS sensor-based monitoring system, which we encapsulate in polyurethane resin. We place the sensor within an oedometer cell and show that despite a rise in swelling pressure to 2 MPa, our relative humidity RH measurements are unaffected. We then test the sensing system against a traditional RH sensor, using saturated bentonite with a range of RH values between 50% and 100%. Measurements differ, on average, by 2.87% RH, and are particularly far apart for values of RH greater than 98%. However, bespoke calibration of the MEMS sensing system using saturated solutions of known RH, reduces the measurement difference to an average of 1.97% RH, greatly increasing the accuracy for RH values close to 100%. View Full-Text

Keywords: monitoring; geological disposal; sensor; relative humidity; bentonite; engineered barrier system; MEMS; geological disposal monitoring; geological disposal; sensor; relative humidity; bentonite; engineered barrier system; MEMS; geological disposal





Author: Wenbin Yang, Rebecca J. Lunn * , Alessandro Tarantino and Gráinne El Mountassir

Source: http://mdpi.com/



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