Article
Version 2
Preserved in Portico This version is not peer-reviewed
Laboratory Testing of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal Facility
Version 1
: Received: 8 May 2017 / Approved: 8 May 2017 / Online: 8 May 2017 (12:30:01 CEST)
Version 2 : Received: 8 May 2017 / Approved: 9 May 2017 / Online: 9 May 2017 (03:54:23 CEST)
Version 2 : Received: 8 May 2017 / Approved: 9 May 2017 / Online: 9 May 2017 (03:54:23 CEST)
A peer-reviewed article of this Preprint also exists.
Yang, W.; Lunn, R.J.; Tarantino, A.; El Mountassir, G. Laboratory Testing of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal Facility. Geosciences 2017, 7, 38. Yang, W.; Lunn, R.J.; Tarantino, A.; El Mountassir, G. Laboratory Testing of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal Facility. Geosciences 2017, 7, 38.
Journal reference: Geosciences 2017, 7, 38
DOI: 10.3390/geosciences7020038
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%.
Keywords
monitoring; geological disposal; sensor; relative humidity; bentonite; engineered barrier system; MEMS; geological disposal
Subject
ENGINEERING, Civil Engineering
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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