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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%.
Original language | English |
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Number of pages | 9 |
Journal | Geosciences |
Volume | 7 |
Issue number | 38 |
DOIs | |
Publication status | Published - 20 May 2017 |
Keywords
- monitoring
- geological disposal
- sensor
- MEMS
- relative humidity
- bentonite
- engineered barrier system
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Dive into the research topics of 'Laboratory testing of a MEMS sensor system for in-situ monitoring of the engineered barrier in a geological disposal facility'. Together they form a unique fingerprint.Projects
- 1 Finished
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SAFE - a Systems Approach For Engineered Barriers
Lunn, R., Saafi, M., Sentenac, P., Shipton, Z. & Tarantino, A.
EPSRC (Engineering and Physical Sciences Research Council)
30/09/12 → 29/03/17
Project: Research