KYT-TERKOR Teräksisten matala- ja keskiaktiivisten ...
Transcript of KYT-TERKOR Teräksisten matala- ja keskiaktiivisten ...
KYT-TERKORCorrosion of low and intermediate level steel waste under in-situ repository conditions
Pauliina Rajala
KYT2022-SAFIR2022 Interim Seminar18.-19.3.2021
TERKORBackground
▪ Steel is studied as possible material included in
maintenance and decommissioning waste
▪ The results support the decisions to be made
concerning the decommissioning phase
• Corrosion rates of the reactor pressure vessels and
other steel components
• Role of corrosion in release of radionuclides to the
environment
…The study also supports the repository of the low and
intermediate level waste produced during operation
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Figure: Safety case for Loviisa LILW repository 2018, Public report LO1-T3552-00023
TERKORObjectives
1. Investigate the effect of steel activation on the corrosion rate
in the final repository conditions
2. Determine the role of microbial community on the corrosion
rate and mechanisms of steels in the final repository conditions
3. Utilize deeper characterization of corrosion products and
biofilms to deepen the understanding of microbially-induced
corrosion (MIC) in the final repository conditions.
4. The goal of the project is to expand and compare corrosion data
to cover the activated steels and other repository environments
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Long-termlaboratoryexperiment(11 months)
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Long-term laboratory experiment(11 months)
▪ Experiment period 11 months
▪ Carbons steel (DC01* AmO ), stainless steels AISI304 (EN 1.4301) and
AISI316(EN 1.4432) and pressure vessel steel 15Kh2MFA from Loviisa
▪ Water from LPVA5, 10°C
▪ Microbial enrichments from LPVA5 water
• Sulphate reducing prokaryotes (SRB), Iron reducing bacteria (IRB),
Iron oxidizing bacteria (IOB)
▪ Real-time monitoring of corrosion rate
▪ Specimens for gravimetric measurements
▪ Specimens for biofilm analyses
▪ Specimens for surface characterization
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Comparison of groundwatersfrom differentrepositorysitesChemistry, microbiology and corrosion
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Comparison of groundwaters fromdifferent repository sitesChemistry, microbiology and corrosion
▪ Materials: carbon steel and two stainless steels (304, 316)
▪ Water from Olkiluoto KR9, Loviisa LPVA 5, Hanhikivi KR4 and
simulated water
▪ Anoxic conditions
▪ Electrochemical measurements
• OCP
• EIS
• Tafel (carbon steel)
• Cyclic anodic polarization (stainless steels)
▪ Microscopy
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Olkiluoto Hanhikivi Loviisa
304, Olkiluoto
Element/characteristic Unit OlkiluotoKR9
HanhikiviKR4
LoviisaLPVA5
Simulated water
pH 8.73 7.33 7.74 7Alkalinity pH 4.5 mmol/L 3.15 5.41 1.82
CO2 (total) mg/L 138 268 87HCO3
- mg/L 192 330 111Phosphate mg/L <0.040 0.068 <0.040Sulphate mg/L 116 482 566 500Sulphide mg/L 0.147 <0.050 <0.010Chloride mg/L 723 3210 4880 5500Ammonium mg/L 0.179 2.9 1.82Ca (soluble) mg/L 56.8 444 615Mg (soluble) mg/L 30.2 109 276Na (soluble) mg/L 489 1380 2210S mg/L 44.4 140 204Si mg/L 2.28 7.23 4.56TOC mg/L 6.37 10.3 1.33Sulphate/chloride ratio 0.16 0.15 0.12 0.09
Effect of activation on corrosion rateof pressurevessel steel
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Effect of activation on corrosion rate of pressure vessel steel
▪ Material: activated and non-activated pressure
vessel steel
▪ Water: LPVA5 and simulated water
▪ Duration 1 year (sampling done 6/2020) and 3
years (2022)
▪ Gravimetric specimens
▪ Specimens for surface characterization (SEM,
EDS)
▪ Specimens for microbial analyses
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Activated pressure vessel steel• Main components on the more smooth area
of corrosion product: Fe, O, Si and S and smaller amounts of Ca, C, Cr, Mg, Al
• Main components in the deposits: Ca, C, O
Non activated pressure vessel steel• Main components on the smoother area of
corrosion products: Cu, Fe and S and smalleramounts of Ca, Cr, Zn
• Main components in the crystalline deposits: Ca, O, C
TERKORSummary
▪ Local groundwater conditions (chemical and biological) have
great effect on corrosion tendency and corrosion form of LILW
▪ Laboratory studies targeted to the effects of different microbial
groups on corrosion show that there are differences regarding of
the microbial species composition
▪ Composition of corrosion product on activated steel differed from
non-activated
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Publications
Yearly report (in Finnish)
▪ Teräksisten matala- ja keskiaktiivisten jätteiden korroosio loppusijoituksen in-situ olosuhteissa (TERKOR) - Vuosiraportti
2019
Scientific publications
▪ Nuppunen-Puputti M, Kietäväinen R, Purkamo L, Rajala P, Itävaara M, Kukkonen I, Bomberg M. Rock Surface Fungi in
Deep Continental Biosphere—Exploration of Microbial Community Formation with Subsurface In Situ Biofilm Trap.
Microorganisms. 2021; 9(1):64.
▪ P. Rajala, E. Huttunen-Saarivirta, M. Bomberg, L. Carpén. 2019. Corrosion and biofouling tendency of carbon steel in
anoxic groundwater containing Sulphate Reducing Bacteria and Methanogenic Archaea. Corrosion Science 159: 108148.
▪ P. Rajala, M. Raulio, L. Carpen, 2019. Sulphate Reducing Bacteria and Methanogenic Archaea Driving Corrosion of Steel
in Deep Anoxic Ground Water. Corrosion Science and Technology 18 (6): 221-227.
▪ L. Carpen, P. Rajala, E. Isotahdon. 2019. The effect of sulfate reducing bacteria and acetogenic bacteria on the corrosion
of carbon steel in crystalline groundwater, Eurocorr 2019, September 9-13 Seville, Spain.
Presentations
▪ Corrosion induced by deep biosphere microorganisms, Indian institute of Technology Delhi, Seminar series, 12.11.2020
▪ Sammonlahden koulu, 9th grade chemistry class
▪ The effect of sulfate reducing bacteria and acetogenic bacteria on the corrosion of carbon steel in crystalline groundwater,
Eurocorr 2019, September 9-13 Seville, Spain.
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The Team
Pauliina Rajala
Leena Carpen
Elisa Isotahdon
Thomas Ohligschläger
Mervi Somervuori
Vilma Ratia-Hanby
Maija Nuppunen-Puputti
Malin Bomberg
Satu Salo
Jarkko Metsäjoki
Taru Lehtikuusi
Tuomo Kinnunen
Seppo Peltonen
Johanna Lukin
Mirva Pyrhönen
KYT-DEMONI