Bentonite Permeability at Elevated Temperature
Repository designs frequently favour geological disposal of radioactive waste with a backfill material occupying void space around the waste. The backfill material must tolerate the high temperatures produced by decaying radioactive waste to prevent its failure or degradation, leading to increased h...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2017-01-01
|
| Series: | Geosciences |
| Subjects: | |
| Online Access: | http://www.mdpi.com/2076-3263/7/1/3 |
| _version_ | 1818037596853370880 |
|---|---|
| author | Katherine A. Daniels Jon F. Harrington Stephanie G. Zihms Andrew C. Wiseall |
| author_facet | Katherine A. Daniels Jon F. Harrington Stephanie G. Zihms Andrew C. Wiseall |
| author_sort | Katherine A. Daniels |
| collection | DOAJ |
| description | Repository designs frequently favour geological disposal of radioactive waste with a backfill material occupying void space around the waste. The backfill material must tolerate the high temperatures produced by decaying radioactive waste to prevent its failure or degradation, leading to increased hydraulic conductivity and reduced sealing performance. The results of four experiments investigating the effect of temperature on the permeability of a bentonite backfill are presented. Bentonite is a clay commonly proposed as the backfill in repository designs because of its high swelling capacity and very low permeability. The experiments were conducted in two sets of purpose-built, temperature controlled apparatus, designed to simulate isotropic pressure and constant volume conditions within the testing range of 4–6 MPa average effective stress. The response of bentonite during thermal loading at temperatures up to 200 °C was investigated, extending the previously considered temperature range. The results provide details of bentonite’s intrinsic permeability, total stress, swelling pressure and porewater pressure during thermal cycles. We find that bentonite’s hydraulic properties are sensitive to thermal loading and the type of imposed boundary condition. However, the permeability change is not large and can mostly be accounted for by water viscosity changes. Thus, under 150 °C, temperature has a minimal impact on bentonite’s hydraulic permeability. |
| first_indexed | 2024-12-10T07:29:22Z |
| format | Article |
| id | doaj.art-39623477650c432982e560033160100d |
| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-12-10T07:29:22Z |
| publishDate | 2017-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Geosciences |
| spelling | doaj.art-39623477650c432982e560033160100d2022-12-22T01:57:36ZengMDPI AGGeosciences2076-32632017-01-0171310.3390/geosciences7010003geosciences7010003Bentonite Permeability at Elevated TemperatureKatherine A. Daniels0Jon F. Harrington1Stephanie G. Zihms2Andrew C. Wiseall3British Geological Survey, Nicker Hill, Keyworth, Nottinghamshire NG12 5GG, UKBritish Geological Survey, Nicker Hill, Keyworth, Nottinghamshire NG12 5GG, UKBritish Geological Survey, Nicker Hill, Keyworth, Nottinghamshire NG12 5GG, UKBritish Geological Survey, Nicker Hill, Keyworth, Nottinghamshire NG12 5GG, UKRepository designs frequently favour geological disposal of radioactive waste with a backfill material occupying void space around the waste. The backfill material must tolerate the high temperatures produced by decaying radioactive waste to prevent its failure or degradation, leading to increased hydraulic conductivity and reduced sealing performance. The results of four experiments investigating the effect of temperature on the permeability of a bentonite backfill are presented. Bentonite is a clay commonly proposed as the backfill in repository designs because of its high swelling capacity and very low permeability. The experiments were conducted in two sets of purpose-built, temperature controlled apparatus, designed to simulate isotropic pressure and constant volume conditions within the testing range of 4–6 MPa average effective stress. The response of bentonite during thermal loading at temperatures up to 200 °C was investigated, extending the previously considered temperature range. The results provide details of bentonite’s intrinsic permeability, total stress, swelling pressure and porewater pressure during thermal cycles. We find that bentonite’s hydraulic properties are sensitive to thermal loading and the type of imposed boundary condition. However, the permeability change is not large and can mostly be accounted for by water viscosity changes. Thus, under 150 °C, temperature has a minimal impact on bentonite’s hydraulic permeability.http://www.mdpi.com/2076-3263/7/1/3bentonitepermeabilitytemperatureradioactive waste disposalclay responsethermal loading |
| spellingShingle | Katherine A. Daniels Jon F. Harrington Stephanie G. Zihms Andrew C. Wiseall Bentonite Permeability at Elevated Temperature Geosciences bentonite permeability temperature radioactive waste disposal clay response thermal loading |
| title | Bentonite Permeability at Elevated Temperature |
| title_full | Bentonite Permeability at Elevated Temperature |
| title_fullStr | Bentonite Permeability at Elevated Temperature |
| title_full_unstemmed | Bentonite Permeability at Elevated Temperature |
| title_short | Bentonite Permeability at Elevated Temperature |
| title_sort | bentonite permeability at elevated temperature |
| topic | bentonite permeability temperature radioactive waste disposal clay response thermal loading |
| url | http://www.mdpi.com/2076-3263/7/1/3 |
| work_keys_str_mv | AT katherineadaniels bentonitepermeabilityatelevatedtemperature AT jonfharrington bentonitepermeabilityatelevatedtemperature AT stephaniegzihms bentonitepermeabilityatelevatedtemperature AT andrewcwiseall bentonitepermeabilityatelevatedtemperature |