Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions
In most countries, the upper limit of the buffer temperature in a geological repository for nuclear waste is set below 100 °C because of possible illitization. This smectite-to-illite transformation likely causes the swelling function of the buffer to deteriorate. However, stipulation of a higher te...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-02-01
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| Series: | Case Studies in Thermal Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X22000387 |
| _version_ | 1798024746259972096 |
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| author | Seok Yoon Gi-Jun Lee Tae-Jin Park Changsoo Lee Dong-Keun Cho |
| author_facet | Seok Yoon Gi-Jun Lee Tae-Jin Park Changsoo Lee Dong-Keun Cho |
| author_sort | Seok Yoon |
| collection | DOAJ |
| description | In most countries, the upper limit of the buffer temperature in a geological repository for nuclear waste is set below 100 °C because of possible illitization. This smectite-to-illite transformation likely causes the swelling function of the buffer to deteriorate. However, stipulation of a higher temperature for the buffer would significantly increase the disposal density and cost effectiveness of the repository. Hence, understanding the characteristics and providing a database of information pertaining to the buffer at elevated temperatures is crucial. This study involved an evaluation of the thermal conductivity of bentonite buffer materials, as this property is the most important parameter for determining the design temperature. An experimental system suitable for operation at high temperatures was established, and was used to measure the thermal conductivity of bentonite buffer materials at different saturation values in the range 0–0.22 from room temperature to 150 °C. The dry density of the bentonite buffer materials is approximately 1.75 g/cm³, and the higher the initial saturation, the higher the measured thermal conductivity. The specimen and probe were placed in an oven and completely sealed with heat resistance tape to prevent water from evaporating from the pores of the specimen. The thermal conductivity of the bentonite buffer materials, which initially increased with temperature, decreased slightly between 100 and 150 °C. In general, the thermal conductivity values were similar between room temperature and 150 °C. |
| first_indexed | 2024-04-11T18:07:36Z |
| format | Article |
| id | doaj.art-77a14ea4f6f149b08ee63a65238b7bce |
| institution | Directory Open Access Journal |
| issn | 2214-157X |
| language | English |
| last_indexed | 2024-04-11T18:07:36Z |
| publishDate | 2022-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Case Studies in Thermal Engineering |
| spelling | doaj.art-77a14ea4f6f149b08ee63a65238b7bce2022-12-22T04:10:17ZengElsevierCase Studies in Thermal Engineering2214-157X2022-02-0130101792Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditionsSeok Yoon0Gi-Jun Lee1Tae-Jin Park2Changsoo Lee3Dong-Keun Cho4Corresponding author.; Disposal Safety Evaluation Research Division, KAERI, Daejeon, 34057, South KoreaDisposal Safety Evaluation Research Division, KAERI, Daejeon, 34057, South KoreaDisposal Safety Evaluation Research Division, KAERI, Daejeon, 34057, South KoreaDisposal Safety Evaluation Research Division, KAERI, Daejeon, 34057, South KoreaDisposal Safety Evaluation Research Division, KAERI, Daejeon, 34057, South KoreaIn most countries, the upper limit of the buffer temperature in a geological repository for nuclear waste is set below 100 °C because of possible illitization. This smectite-to-illite transformation likely causes the swelling function of the buffer to deteriorate. However, stipulation of a higher temperature for the buffer would significantly increase the disposal density and cost effectiveness of the repository. Hence, understanding the characteristics and providing a database of information pertaining to the buffer at elevated temperatures is crucial. This study involved an evaluation of the thermal conductivity of bentonite buffer materials, as this property is the most important parameter for determining the design temperature. An experimental system suitable for operation at high temperatures was established, and was used to measure the thermal conductivity of bentonite buffer materials at different saturation values in the range 0–0.22 from room temperature to 150 °C. The dry density of the bentonite buffer materials is approximately 1.75 g/cm³, and the higher the initial saturation, the higher the measured thermal conductivity. The specimen and probe were placed in an oven and completely sealed with heat resistance tape to prevent water from evaporating from the pores of the specimen. The thermal conductivity of the bentonite buffer materials, which initially increased with temperature, decreased slightly between 100 and 150 °C. In general, the thermal conductivity values were similar between room temperature and 150 °C.http://www.sciencedirect.com/science/article/pii/S2214157X22000387Bentonite buffer materialThermal conductivityElevated temperature conditions |
| spellingShingle | Seok Yoon Gi-Jun Lee Tae-Jin Park Changsoo Lee Dong-Keun Cho Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions Case Studies in Thermal Engineering Bentonite buffer material Thermal conductivity Elevated temperature conditions |
| title | Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions |
| title_full | Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions |
| title_fullStr | Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions |
| title_full_unstemmed | Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions |
| title_short | Thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions |
| title_sort | thermal conductivity evaluation for bentonite buffer materials under elevated temperature conditions |
| topic | Bentonite buffer material Thermal conductivity Elevated temperature conditions |
| url | http://www.sciencedirect.com/science/article/pii/S2214157X22000387 |
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