Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository

In deep geological disposal system designs, it is important to minimize the installation area for cost effectiveness while satisfying the thermal requirements of the systems. An effective method to reduce the installation area for the systems is to employ an enhanced buffer material, as this can dec...

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Main Authors: Min-Jun Kim, Gi-Jun Lee, Seok Yoon
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/11/18/8733
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author Min-Jun Kim
Gi-Jun Lee
Seok Yoon
author_facet Min-Jun Kim
Gi-Jun Lee
Seok Yoon
author_sort Min-Jun Kim
collection DOAJ
description In deep geological disposal system designs, it is important to minimize the installation area for cost effectiveness while satisfying the thermal requirements of the systems. An effective method to reduce the installation area for the systems is to employ an enhanced buffer material, as this can decrease the spacing between the disposal tunnels and deposition holes. Therefore, this study aims to evaluate the effect of an enhanced buffer material on the thermal behavior of the systems and their spacing. First, the discrete element method (DEM) was adopted to validate the thermal conductivity of the enhanced buffer material used, which was a mixture of bentonite and graphite. Then, a 3D finite element method (FEM) was conducted to analyze the proper disposal tunnel and hole spacing considering three cases with thermal conductivities values of the buffer as 0.8 W/(m K), 1.0 W/(m K), and 1.2 W/(m K). The results showed that the disposal tunnel and hole spacing could be reduced to 30 m and 6 m, respectively, when the temperature of the buffer surface facing the canister was 100 °C with a thermal conductivity value of approximately 1.2 W/(m K) or if more than 3% of graphite is added.
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spelling doaj.art-2a9423ab390f4abe8a42eccb37353bc72023-11-22T11:57:24ZengMDPI AGApplied Sciences2076-34172021-09-011118873310.3390/app11188733Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste RepositoryMin-Jun Kim0Gi-Jun Lee1Seok Yoon2Deep Subsurface Research Center, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon 34132, KoreaRadioactive Waste Disposal Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, KoreaRadioactive Waste Disposal Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, KoreaIn deep geological disposal system designs, it is important to minimize the installation area for cost effectiveness while satisfying the thermal requirements of the systems. An effective method to reduce the installation area for the systems is to employ an enhanced buffer material, as this can decrease the spacing between the disposal tunnels and deposition holes. Therefore, this study aims to evaluate the effect of an enhanced buffer material on the thermal behavior of the systems and their spacing. First, the discrete element method (DEM) was adopted to validate the thermal conductivity of the enhanced buffer material used, which was a mixture of bentonite and graphite. Then, a 3D finite element method (FEM) was conducted to analyze the proper disposal tunnel and hole spacing considering three cases with thermal conductivities values of the buffer as 0.8 W/(m K), 1.0 W/(m K), and 1.2 W/(m K). The results showed that the disposal tunnel and hole spacing could be reduced to 30 m and 6 m, respectively, when the temperature of the buffer surface facing the canister was 100 °C with a thermal conductivity value of approximately 1.2 W/(m K) or if more than 3% of graphite is added.https://www.mdpi.com/2076-3417/11/18/8733enhanced bufferFEMDEMthermal conductivityhigh-level radioactive waste repository
spellingShingle Min-Jun Kim
Gi-Jun Lee
Seok Yoon
Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
Applied Sciences
enhanced buffer
FEM
DEM
thermal conductivity
high-level radioactive waste repository
title Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
title_full Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
title_fullStr Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
title_full_unstemmed Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
title_short Numerical Study on the Effect of Enhanced Buffer Materials in a High-Level Radioactive Waste Repository
title_sort numerical study on the effect of enhanced buffer materials in a high level radioactive waste repository
topic enhanced buffer
FEM
DEM
thermal conductivity
high-level radioactive waste repository
url https://www.mdpi.com/2076-3417/11/18/8733
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