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The mobility of nat...
The mobility of natural uranium at Forsmark, Sweden, through geologic time
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- Krall, Lindsay, 1988- (författare)
- Stockholms universitet,Institutionen för geologiska vetenskaper
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- Mörth, Carl-Magnus, Professor (preses)
- Stockholms universitet,Institutionen för geologiska vetenskaper
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- Read, David, Professor (opponent)
- University of Surrey
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(creator_code:org_t)
- ISBN 9789176495957
- Stockholm : Department of Geological Sciences, Stockholm University, 2016
- Engelska 28 s.
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Serie: Meddelanden från Stockholms universitets institution för geologiska vetenskaper ; 365
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Abstract
Ämnesord
Stäng
- In this thesis, the response of uranium minerals and poorly crystalline phases to changes in geochemical conditions through geological time has been assessed in order to understand the mobility of natural uranium in the fracture network of a proposed site for a spent nuclear fuel repository in Forsmark, Sweden. Identification and characterization of solid phase uranium have been performed through electron microprobe analysis and optical petrography (Article I). The identified uraninite, haiweeite, and uranophane crystals have been dated using U-Pb and Pb-Pb isotope ratios obtained from secondary ion mass spectrometry and laser ablation-inductively coupled plasma-mass spectrometry (Article II). The mobility of uranium in current Forsmark groundwaters and fracture system has been modelled using the PHREEQC geochemical program and Ra and Rn isotope systematics (Article IV). The rate of submarine groundwater discharge (SGD) from the Forsmark coast to Öregrundsgrepen has also been modelled using Ra isotopes (Article V). Results from these studies support a geologically early (~1200 Ma) oxidation of U(IV) to U(VI). It is further suggested that the old U(VI) minerals present in the bedrock are soluble at the pe values and alkalinities observed in the Forsmark groundwaters. At pe < −4.6 and alkalinity < 60 mg/L, U(VI) can be reduced to U(IV) and deposited in the fracture network. Although a non-negligible rate of SGD has been observed, this cannot be attributed to the discharge of deep (>200 m.b.s.l.) Forsmark groundwaters on the basis of current data.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geology (hsv//eng)
Nyckelord
- uranium
- radium
- mineralogy
- geochronology
- submarine groundwater discharge
- spent nuclear fuel
- geochemical modelling
- Geology
- geologi
Publikations- och innehållstyp
- vet (ämneskategori)
- dok (ämneskategori)
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