Lot A2 test, THC modelling of the bentonite buffer

Aku Itälä (Corresponding Author), Markus Olin, Jarmo Lehikoinen

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

Finnish spent nuclear fuel is planned to be disposed of deep in the crystalline bedrock of the Olkiluoto island. In such a repository, the role of the bentonite buffer is considered to be central. The initially unsaturated bentonite emplaced around a spent-fuel canister will become fully saturated by the groundwater from the host rock. In order to assess the long-term safety of a deep repository, it is essential to determine how temperature influences the chemical stability of bentonite. The aim of this study was to achieve an improved understanding of the factors governing the thermo-hydro-chemical evolution of the bentonite buffer subject to heat generation from the disposed fuel and in contact with a highly permeable rock fracture intersecting a canister deposition hole.

TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the Äspö hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite porewater chemistry, mineralogy, and saturation of the buffer are presented and discussed. The calculated model results show similarity to the experimental results. In particular, the spatial differences in the saturation and porewater chemistry of the bentonite buffer were clearly visible in the model.

Original languageEnglish
Pages (from-to)1830-1837
Number of pages8
JournalPhysics and Chemistry of the Earth
Volume36
Issue number17-18
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed

Fingerprint

thermohaline circulation
Bentonite
bentonite
Dronabinol
Buffers
buffers
cans
modeling
spent fuels
Spent fuels
Rocks
saturation (chemistry)
rocks
repository
porewater
saturation
chemistry
Mineralogy
Sweden
nuclear fuels

Keywords

  • THC
  • modelling
  • cation exchange
  • nuclear waste
  • heat transport
  • bentonite

Cite this

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title = "Lot A2 test, THC modelling of the bentonite buffer",
abstract = "Finnish spent nuclear fuel is planned to be disposed of deep in the crystalline bedrock of the Olkiluoto island. In such a repository, the role of the bentonite buffer is considered to be central. The initially unsaturated bentonite emplaced around a spent-fuel canister will become fully saturated by the groundwater from the host rock. In order to assess the long-term safety of a deep repository, it is essential to determine how temperature influences the chemical stability of bentonite. The aim of this study was to achieve an improved understanding of the factors governing the thermo-hydro-chemical evolution of the bentonite buffer subject to heat generation from the disposed fuel and in contact with a highly permeable rock fracture intersecting a canister deposition hole.TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the {\"A}sp{\"o} hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite porewater chemistry, mineralogy, and saturation of the buffer are presented and discussed. The calculated model results show similarity to the experimental results. In particular, the spatial differences in the saturation and porewater chemistry of the bentonite buffer were clearly visible in the model.",
keywords = "THC, modelling, cation exchange, nuclear waste, heat transport, bentonite",
author = "Aku It{\"a}l{\"a} and Markus Olin and Jarmo Lehikoinen",
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Lot A2 test, THC modelling of the bentonite buffer. / Itälä, Aku (Corresponding Author); Olin, Markus; Lehikoinen, Jarmo.

In: Physics and Chemistry of the Earth, Vol. 36, No. 17-18, 2011, p. 1830-1837.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Itälä, Aku

AU - Olin, Markus

AU - Lehikoinen, Jarmo

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PY - 2011

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N2 - Finnish spent nuclear fuel is planned to be disposed of deep in the crystalline bedrock of the Olkiluoto island. In such a repository, the role of the bentonite buffer is considered to be central. The initially unsaturated bentonite emplaced around a spent-fuel canister will become fully saturated by the groundwater from the host rock. In order to assess the long-term safety of a deep repository, it is essential to determine how temperature influences the chemical stability of bentonite. The aim of this study was to achieve an improved understanding of the factors governing the thermo-hydro-chemical evolution of the bentonite buffer subject to heat generation from the disposed fuel and in contact with a highly permeable rock fracture intersecting a canister deposition hole.TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the Äspö hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite porewater chemistry, mineralogy, and saturation of the buffer are presented and discussed. The calculated model results show similarity to the experimental results. In particular, the spatial differences in the saturation and porewater chemistry of the bentonite buffer were clearly visible in the model.

AB - Finnish spent nuclear fuel is planned to be disposed of deep in the crystalline bedrock of the Olkiluoto island. In such a repository, the role of the bentonite buffer is considered to be central. The initially unsaturated bentonite emplaced around a spent-fuel canister will become fully saturated by the groundwater from the host rock. In order to assess the long-term safety of a deep repository, it is essential to determine how temperature influences the chemical stability of bentonite. The aim of this study was to achieve an improved understanding of the factors governing the thermo-hydro-chemical evolution of the bentonite buffer subject to heat generation from the disposed fuel and in contact with a highly permeable rock fracture intersecting a canister deposition hole.TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the Äspö hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite porewater chemistry, mineralogy, and saturation of the buffer are presented and discussed. The calculated model results show similarity to the experimental results. In particular, the spatial differences in the saturation and porewater chemistry of the bentonite buffer were clearly visible in the model.

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