Geology of Olkiluoto: the disposal site for spent nuclear fuel in Finland

Ismo S. Aaltonen; Jon O. Engström; Kai A. Front; Seppo A. Gehör; Aulis J. Kärki; Paula J. Kosunen; Jussi A. Mattila; Markku Paananen; Seppo Paulamäki

Abstract

Olkiluoto Island, which is located in SW Finland, has been selected as the deep geological repository for the high-level nuclear waste generated by the nuclear power plants operated by the Finnish power companies TVO and Fortum, and the repository is expected to become operational in the early 2020s. Posiva is an expert organisation responsible for the management and implementation of the nuclear waste repository at Olkiluoto and is owned by TVO and Fortum. Posiva submitted a construction licence application to the Finnish government in December 2012 and an integrated description of the Olkiluoto site, including its geology, was a part of the background material. After their review, in early 2015, the Radiation and Nuclear Safety Authority in Finland (STUK) gave a positive statement to the Ministry of Employment and the Economy: "the final disposal facility designed by Posiva can be built to be safe".Posiva has continued updating the multidisciplinary site description, which is aiming at the last licencing stage of the repository - the application of the operating licence. Understanding the geology of Olkiluoto is a substantial part of the site description work. It is based on data from hundreds of outcrops, tens of kilometers of drill core, extensive tunnel mapping programme and a wide variety of geophysical investigations. The Palaeoproterozoic bedrock in Olkiluoto consists of variably migmatised supracrustal high-grade metamorphic rocks: migmatized meta-pelites, meta-arenites and intermediate, pyroclastic metavolcanites. They are intruded by Paleoproterozoic felsic, granitic–tonalitic plutonic rocks and granitic pegmatoids, and diabase dikes. The rocks were metamorphosed simultaneously with the different phases of ductile deformation. Hydrothermal alteration at Olkiluoto can be subdivided into two different modes on the basis how the fluids have proceeded in the rock mass: fracture- or veinlet-controlled alteration and pervasive or disseminated alteration. The brittle deformation history of Olkiluoto can be reconstructed through paleostress inversion of fault-slip data from outcrops and drill cores and from K-Ar ages if fault gouge illites: seven distinct paleostress states can be identified, spanning in time from ca. 1.7 Ga to 1.0 Ga.

Original language	English
Publication status	Published - 2015
Event	2015 GSA Annual Meeting in Baltimore, Maryland, USA - Maryland, United States Duration: 1 Nov 2015 → 4 Nov 2015 https://gsa.confex.com/gsa/2015AM/webprogram/start.html (2015 GSA Annual Meeting in Baltimore, Maryland, USA)

Conference

Conference	2015 GSA Annual Meeting in Baltimore, Maryland, USA
Abbreviated title	GSA 2015
Country/Territory	United States
City	Maryland
Period	1/11/15 → 4/11/15
Internet address	https://gsa.confex.com/gsa/2015AM/webprogram/start.html (2015 GSA Annual Meeting in Baltimore, Maryland, USA)

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https://gsa.confex.com/gsa/2015AM/webprogram/Paper258938.html

Cite this

Aaltonen, I. S., Engström, J. O., Front, K. A., Gehör, S. A., Kärki, A. J., Kosunen, P. J., Mattila, J. A., Paananen, M., & Paulamäki, S. (2015). Geology of Olkiluoto: the disposal site for spent nuclear fuel in Finland. Abstract from 2015 GSA Annual Meeting in Baltimore, Maryland, USA, Maryland, Maryland, United States. https://gsa.confex.com/gsa/2015AM/webprogram/Paper258938.html

@conference{2cf4751ec14f4a918d47d04aa6077964,

title = "Geology of Olkiluoto: the disposal site for spent nuclear fuel in Finland",

abstract = "Olkiluoto Island, which is located in SW Finland, has been selected as the deep geological repository for the high-level nuclear waste generated by the nuclear power plants operated by the Finnish power companies TVO and Fortum, and the repository is expected to become operational in the early 2020s. Posiva is an expert organisation responsible for the management and implementation of the nuclear waste repository at Olkiluoto and is owned by TVO and Fortum. Posiva submitted a construction licence application to the Finnish government in December 2012 and an integrated description of the Olkiluoto site, including its geology, was a part of the background material. After their review, in early 2015, the Radiation and Nuclear Safety Authority in Finland (STUK) gave a positive statement to the Ministry of Employment and the Economy: {"}the final disposal facility designed by Posiva can be built to be safe{"}.Posiva has continued updating the multidisciplinary site description, which is aiming at the last licencing stage of the repository - the application of the operating licence. Understanding the geology of Olkiluoto is a substantial part of the site description work. It is based on data from hundreds of outcrops, tens of kilometers of drill core, extensive tunnel mapping programme and a wide variety of geophysical investigations. The Palaeoproterozoic bedrock in Olkiluoto consists of variably migmatised supracrustal high-grade metamorphic rocks: migmatized meta-pelites, meta-arenites and intermediate, pyroclastic metavolcanites. They are intruded by Paleoproterozoic felsic, granitic–tonalitic plutonic rocks and granitic pegmatoids, and diabase dikes. The rocks were metamorphosed simultaneously with the different phases of ductile deformation. Hydrothermal alteration at Olkiluoto can be subdivided into two different modes on the basis how the fluids have proceeded in the rock mass: fracture- or veinlet-controlled alteration and pervasive or disseminated alteration. The brittle deformation history of Olkiluoto can be reconstructed through paleostress inversion of fault-slip data from outcrops and drill cores and from K-Ar ages if fault gouge illites: seven distinct paleostress states can be identified, spanning in time from ca. 1.7 Ga to 1.0 Ga.",

author = "Aaltonen, {Ismo S.} and Engstr{\"o}m, {Jon O.} and Front, {Kai A.} and Geh{\"o}r, {Seppo A.} and K{\"a}rki, {Aulis J.} and Kosunen, {Paula J.} and Mattila, {Jussi A.} and Markku Paananen and Seppo Paulam{\"a}ki",

year = "2015",

language = "English",

note = "2015 GSA Annual Meeting in Baltimore, Maryland, USA, GSA 2015 ; Conference date: 01-11-2015 Through 04-11-2015",

url = "https://gsa.confex.com/gsa/2015AM/webprogram/start.html",

}

TY - CONF

T1 - Geology of Olkiluoto

T2 - 2015 GSA Annual Meeting in Baltimore, Maryland, USA

AU - Aaltonen, Ismo S.

AU - Engström, Jon O.

AU - Front, Kai A.

AU - Gehör, Seppo A.

AU - Kärki, Aulis J.

AU - Kosunen, Paula J.

AU - Mattila, Jussi A.

AU - Paananen, Markku

AU - Paulamäki, Seppo

PY - 2015

Y1 - 2015

N2 - Olkiluoto Island, which is located in SW Finland, has been selected as the deep geological repository for the high-level nuclear waste generated by the nuclear power plants operated by the Finnish power companies TVO and Fortum, and the repository is expected to become operational in the early 2020s. Posiva is an expert organisation responsible for the management and implementation of the nuclear waste repository at Olkiluoto and is owned by TVO and Fortum. Posiva submitted a construction licence application to the Finnish government in December 2012 and an integrated description of the Olkiluoto site, including its geology, was a part of the background material. After their review, in early 2015, the Radiation and Nuclear Safety Authority in Finland (STUK) gave a positive statement to the Ministry of Employment and the Economy: "the final disposal facility designed by Posiva can be built to be safe".Posiva has continued updating the multidisciplinary site description, which is aiming at the last licencing stage of the repository - the application of the operating licence. Understanding the geology of Olkiluoto is a substantial part of the site description work. It is based on data from hundreds of outcrops, tens of kilometers of drill core, extensive tunnel mapping programme and a wide variety of geophysical investigations. The Palaeoproterozoic bedrock in Olkiluoto consists of variably migmatised supracrustal high-grade metamorphic rocks: migmatized meta-pelites, meta-arenites and intermediate, pyroclastic metavolcanites. They are intruded by Paleoproterozoic felsic, granitic–tonalitic plutonic rocks and granitic pegmatoids, and diabase dikes. The rocks were metamorphosed simultaneously with the different phases of ductile deformation. Hydrothermal alteration at Olkiluoto can be subdivided into two different modes on the basis how the fluids have proceeded in the rock mass: fracture- or veinlet-controlled alteration and pervasive or disseminated alteration. The brittle deformation history of Olkiluoto can be reconstructed through paleostress inversion of fault-slip data from outcrops and drill cores and from K-Ar ages if fault gouge illites: seven distinct paleostress states can be identified, spanning in time from ca. 1.7 Ga to 1.0 Ga.

AB - Olkiluoto Island, which is located in SW Finland, has been selected as the deep geological repository for the high-level nuclear waste generated by the nuclear power plants operated by the Finnish power companies TVO and Fortum, and the repository is expected to become operational in the early 2020s. Posiva is an expert organisation responsible for the management and implementation of the nuclear waste repository at Olkiluoto and is owned by TVO and Fortum. Posiva submitted a construction licence application to the Finnish government in December 2012 and an integrated description of the Olkiluoto site, including its geology, was a part of the background material. After their review, in early 2015, the Radiation and Nuclear Safety Authority in Finland (STUK) gave a positive statement to the Ministry of Employment and the Economy: "the final disposal facility designed by Posiva can be built to be safe".Posiva has continued updating the multidisciplinary site description, which is aiming at the last licencing stage of the repository - the application of the operating licence. Understanding the geology of Olkiluoto is a substantial part of the site description work. It is based on data from hundreds of outcrops, tens of kilometers of drill core, extensive tunnel mapping programme and a wide variety of geophysical investigations. The Palaeoproterozoic bedrock in Olkiluoto consists of variably migmatised supracrustal high-grade metamorphic rocks: migmatized meta-pelites, meta-arenites and intermediate, pyroclastic metavolcanites. They are intruded by Paleoproterozoic felsic, granitic–tonalitic plutonic rocks and granitic pegmatoids, and diabase dikes. The rocks were metamorphosed simultaneously with the different phases of ductile deformation. Hydrothermal alteration at Olkiluoto can be subdivided into two different modes on the basis how the fluids have proceeded in the rock mass: fracture- or veinlet-controlled alteration and pervasive or disseminated alteration. The brittle deformation history of Olkiluoto can be reconstructed through paleostress inversion of fault-slip data from outcrops and drill cores and from K-Ar ages if fault gouge illites: seven distinct paleostress states can be identified, spanning in time from ca. 1.7 Ga to 1.0 Ga.

M3 - Conference Abstract

Y2 - 1 November 2015 through 4 November 2015