Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
Abstract
:1. Introduction
2. Preparation for the Numerical Analysis
2.1. Input Parameters for DEM
2.2. Construction of the Numerical Model
3. Results: Numerical Analysis
3.1. Validation
3.1.1. Input Parameters for DEM
3.1.2. Thermal Analysis Using FEM
3.2. Parametric Study
4. Discussion
5. Conclusions
- A high-performance buffer material with improved thermal conductivity was used in the study. We analyzed the reduction in the distance between the disposal tunnels and disposal holes from the R-SNF of KRS+ conditions in 3D using the FEM model.
- When a buffer material with a thermal conductivity of approximately 1.2 W/(m∙K) added with graphite was used, the R-SNF condition of 40 m distance between the disposal tunnels and 7.5 m distance between the disposal holes could be reduced to 30 m and 6 m between the disposal tunnels and between the disposal holes, respectively.
- Additionally, the thermal conductivity test results conducted by Lee et al. (2013) [17] for bentonite mixed with graphite matched well with the results obtained from the DEM numerical analysis verification.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Conflicts of Interest
References
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Density (kg/m3) | Thermal Conductivity (W/(m∙K)) | Specific Heat Capacity (J/kgK) | |
---|---|---|---|
Copper Shell | 8900 | 386 | 383 |
Cast Insert | 7200 | 52 | 504 |
Backfill | 1970 | 0.8 | 1380 |
Rock | 2270 | 2 | 1190 |
Bentonite Buffer | Parametric study |
Items | y0 | x0 | A1 | t1 |
Value | 297.9526 | 0.7805 | 3218.3828 | 2.9441 |
Itemps | A2 | t2 | A3 | t3 |
Value | 10394.9385 | 1.0966 | 2036.4309 | 42.7499 |
Case | Tunnel Spacing (m) | Hole Spacing (m) | Thermal Conductivity of Buffer (W/(m∙K)) |
---|---|---|---|
1 | 40 | 7.5 | 0.8 |
2 | 1.0 | ||
3 | 1.2 | ||
4 | 30 | 6.0 | 0.8 |
5 | 1.0 | ||
6 | 1.2 | ||
7 | 20 | 4.5 | 0.8 |
8 | 1.0 | ||
9 | 1.2 |
Cases | Thermal Conductivities (λ, W/(m∙K)) | |||
---|---|---|---|---|
0.8 | 1.0 | 1.2 | ||
Tunnel spacing: 40 m Hole spacing: 7.5 m | Max.temperature (T, °C) | 94.53 | 88.85 | 85.15 |
Time to reach max.T (years) | 11.3 | 11.5 | 15.7 | |
Tunnel spacing: 30 m Hole spacing: 6.0 m | Max.temperature (T, °C) | 108.28 | 103.66 | 100.76 |
Time to reach max.T (years) | 20.4 | 26.1 | 34.9 | |
Tunnel spacing: 20 m Hole spacing: 4.5 m | Max.temperature (T, °C) | Divergence within 55 years | ||
Time to reach max.T (years) |
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Kim, M.-J.; Lee, G.-J.; Yoon, S. Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository. Appl. Sci. 2021, 11, 8733. https://doi.org/10.3390/app11188733
Kim M-J, Lee G-J, Yoon S. Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository. Applied Sciences. 2021; 11(18):8733. https://doi.org/10.3390/app11188733
Chicago/Turabian StyleKim, Min-Jun, Gi-Jun Lee, and Seok Yoon. 2021. "Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository" Applied Sciences 11, no. 18: 8733. https://doi.org/10.3390/app11188733
APA StyleKim, M.-J., Lee, G.-J., & Yoon, S. (2021). Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository. Applied Sciences, 11(18), 8733. https://doi.org/10.3390/app11188733