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I’ve been the group leader of the Radionuclides migration in porous bedrock group at the Department of Chemistry since year 2000. I have 30 years of experience in the research field of spent nuclear fuel disposal.  My interests are in sorption and diffusion of safety relevant radionuclides in the engineered and natural barriers of the spent nuclear fuel repository. In addition I have developed in collaboration with the Finnish Radiation and Nuclear Safety Authority STUK a method for analyzing the porosity and pore structure of low porous materials with C-14 PMMA autoradiography technique.

As I completed my Ph.D. thesis within the framework of Cotutelle agreement that granted me the Ph.D. both in Finland and in France, I have strong research connections in France.  These include the Institut de Chimie des Milieux et Matériaux at Poitiers University, French Institute for Radiological Protection and Nuclear Safety and the French Geological Survey.  I have been a member of the International Steering Committee for Grimsel Test Site (GTS) Phase VI since 2004 and our group has worked in the in situ projects in GTS together with an international research groups managed by Nagra, Switzerland. During years 2009-2013 we had an EU project together with Poitiers University and ERM company to transfer the knowledge and build them a shared laboratory for the use of C-14 PMMA method.  I have research collaborations also with Posiva, Finland, University of Jyväskylä, Finland, Geological Survey of Finland, University of Bern, Switzerland, JAEA, Japan, VTT Technical Research Centre of Finland, NRI-Rez, Czech Republic, Royal Institute of Technology, Sweden and Technical University of Gothenburg and Geosigma, Sweden. I am also an expert member in the national CCE fission group in the Ministry of Economic Affairs and Employment in Finland.

Tuhat

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I got my M.Sc. degree at Helsinki University of Technology (presently Aalto University), majoring in nuclear and energy techniques and mathematics.  After that, I continued my studies in University of Jyväskylä and joined the gammaspectroscopy group at the accelerator laboratory of its Department of Physics.  My Ph.D. thesis is about coexisting nuclear shapes in neutron-deficient polonium nuclei.  The Ph.D. was followed by one year of post doc at GSI, Darmstadt, Germany, working with nuclear reaction studies. In the year 2001, I was appointed to my present position at the Department of Chemistry.  My work includes technical support and development of the nuclear spectrometers and the cyclotron, as well as teaching of nuclear spectrometry.  I also act as a radiation safety officer for the department.  My research project is on radionuclide-implanted nanoparticles for theranostic applications.  I’m also involved in in-situ studies of retention of radionuclides in rock matrix.

Tuhat

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I work as a university researcher at the radiochemistry unit at the Department of Chemistry.  I have my M.Sc. and Ph.D. degree from the University of Helsinki, majoring in radiochemistry. My Ph.D. thesis was about radionuclide migration in crystalline rock fractures and demonstration of matrix diffusion affecting the transport and retardation behaviour of radionuclides in fracture flow. My research is related to the safety relevant radionuclide migration in granitic rock and the long-term performance of the bentonite buffer. My projects are on the bentonite erosion, the stability of formed colloids, the radionuclide-colloid interaction and the colloid-facilitated transport of radionuclides. I am collaborating with Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Karlsruher Institut für Technologie (KIT) and Nagra Grimsel Test Site programme Colloid Formation and Migration (CFM).

Tuhat

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I obtained my degree of Bachelor of Science in 1983 majoring in mathematics and minoring in theoretical physics and physics. I defended my PhD thesis in 1994. Until 2002 I worked as a mathematician in the universities of Jyväskylä and Kuopio after which I started to work with mathematical modelling in the Physics Department of the University of Jyväskylä. I started to work in the Department of Chemistry in the University of Helsinki in 2014 and my research is about modelling transport and diffusion experiments.

Tuhat

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I got my MSc degree from the University of Helsinki in 2011, majoring in polymer chemistry. Thereafter I started PhD studies at the University of Helsinki, in the field of radiochemistry. My PhD work focused on developing further the C-14-PMMA impregnation technique used in the structural characterisation of porous materials, such as crystalline and sedimentary rock. I spent part of my PhD studies as a visiting PhD student in the University of Poitiers, France. I defended my thesis in the December 2017, and since then I’ve been working as a post-doc researcher in a project related to the diffusion of radionuclides in reinforced concrete.

My research interests in general are the application of polymers and radioactive tracers in the study of various porous materials. This type of work combines polymer and radiochemistry with application-related fields such geology, soil science or material science. Besides the PhD work, I’ve been involved in the characterisation studies of argillite-cement-interfaces from Tournemire Underground laboratory, and in other projects related to rock matrix characterisation. I also teach in the radiochemistry courses and supervise undergraduate students.

Tuhat

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I am currently a PhD student at the Radiochemistry Unit, Department of Chemistry and my PhD studies are funded by the China Scholarship Council (CSC). My main work now is to study the sorption behaviour of Se(IV) on Grimsel granodiorite and its main minerals (mainly biotite) by both batch sorption experiments and model making, including surface complexation model and molecular model. I got my M.Sc. Degree at China Institute of Atomic Energy (CIAE) in 2014, majoring in nuclear and radiochemistry. The studies were focused on the forming and influence of Np(V)-U(VI) cation-cation complexes on redox behaviours of Np(V) in PUREX process. After graduating from CIAE as a master student, I continued working there for one year, from 2014 to 2015, to study the influence of iron-containing materials on redox behaviours of U and Np in nuclear waste repository conditions. From the October of 2015, I began my work in the University of Helsinki as a Ph.D. student in the Doctoral Programme for Chemistry and Molecular Sciences (CHEMS-DP). My main research interests lie in the usage of different modelling methods to study the sorption mechanisms of Se(IV) on minerals like biotite.

Tuhat

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I got my M.Sc. degree in 2012 from the University of Helsinki majoring in radiochemistry and I have been a part of the Radiochemistry unit since then. My M.Sc. degree focused on sorption and speciation of radionuclides in mineral soils. After my M.Sc. degree I have studied the sorption of radionuclides to mineral soils as well as to peat and bacteria. My work in the University of Helsinki has been focused on the safety assessment of disposal of spent nuclear fuel. I have also done collaboration with fuel industry for developing new analysis methods for biofuels. I came to the RIP-group in spring 2015 and now I’m a licentiate student under Marja Siitari-Kauppi’s supervision. In my licentiate studies I study the retention of radionuclides in Olkiluoto rock matrix via in-situ and laboratory experiments.

Tuhat

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I received my MSc degree in theoretical physics from the University of Helsinki in 2013. After that, I worked at the VTT Technical Research Centre of Finland Ltd in the nuclear waste management team doing molecular modelling on swelling clay minerals. While working, I started PhD studies at the University of Helsinki in 2015 in the doctoral programme in Materials Research and Nanosciences. In my PhD project I apply classical molecular dynamics simulations to study nano level phenomena in swelling clay minerals, including crystalline swelling, ion transport and radiation damage. In 2018 I joined the disposal of spent nuclear fuel group at the Department of Chemistry where I continue my PhD research and bring along an additional molecular modelling tool to the group.

I got my M.Sc. degree in 1991 at University of Joensuu (presently University of Eastern Finland) in physical chemistry. After that, I continued my studies in physical chemistry and inorganic chemistry at University of Joensuu, and I attained Ph.D. degree in physical chemistry in 1996. In my Ph.D. thesis, I used molecular modelling techniques to study the functionality of Ziegler-Natta catalysts. After the Ph.D., I transferred to VTT Technical Research Centre of Finland. My main duty was to study surface phenomena using molecular modelling techniques. Applications were e.g. fouling of heat transfer surfaces, catalysts for fuel cells, electrolysis of water, low melting solvent mixtures and mineral surfaces as a sorbent for radionuclides. In 2015, I joined to Radiochemistry at the University of Helsinki and introduced quantum mechanical computations into the research of final disposal of spent nuclear fuel. Further, I’m involved in e.g. development of molecular layer deposition (MLD) surfaces and metallic alloy catalysts.

I have worked with radiochemistry in the RIP research team of Dr. Marja Siitari-Kauppi since 2017, when I investigated concrete samples with the C14-PMMA porosity analysis as my Bachelor's thesis as a part of an industrial project. After this, I was hired as a laboratory and research assistant for the team. Since then I have completed my Master's thesis with the topic of radium sorption in biotite in the spring of 2020. Starting from autumn of the same year, I have been continuing my research with radium behaviour in geologic media as a Posiva Oy funded Ph.D. student in the Doctoral Programme for Chemistry and Molecular Sciences (CHEMS). As a part of my Ph.D. project, I will be conducting sorption and migration analyses for radium to examine its transport and surface behaviour in geologic media and to provide valuable data for the safety case analysis of Olkiluoto deep geological repository ONKALO. In addition to this, the research data will be used to further improve the accuracy of the geochemical modelling software PHREEQC. As a part of my research initiative, I will also be contributing to the EURAD/Future project with radium migration studies by column and structural analyses of fractured rock.