We are the people in the Nuclear waste disposal group.
Marja Siitari-Kauppi

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.

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Juuso Sammaljärvi

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.

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Xiaodong Li

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.

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Otto Tikkanen

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.

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Noora Pakkanen

I started working in the RIP research team back in the summer of 2018, when I began my Bachelor work under supervision of Pirkko Hölttä. After finishing my Bachelor´s Thesis, I continued to work in the team as a part-time research assistant. In 2020 I finished my Master´s Thesis while still working part time within the group and in January 2021, I began working full-time with RIP-team´s industrial projects. Later that year, I finalized my Master studies and received a grant for postgraduate studies from Fortum & Neste Foundation. Topic of my PhD research is “Radionuclide transport with colloids in fractured rock”, where I will be studying the effect of detached bentonite colloids on sorption and migration behavior of actinide analogue with granitic rock samples. Besides industrial projects and PhD research, I am also taking part in EURAD Hitec -project and I update RIP-team´s website.

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Markus Nyman

I did my M.Sc. degree in the University of Jyväskylä, getting involved in gamma-ray and charged-particle spectroscopy and their application in nuclear structure physics. I continued as a Ph.D. student in the Gamma Spectroscopy group at the Accelerator Laboratory, finally completing my thesis in experimental nuclear physics - spectroscopic studies of very neutron-deficient bismuth and astatine isotopes to be more exact. Immediately after that I spent a nice year here in the Laboratory of Radiochemistry, University of Helsinki, as a substitute for the senior laboratory engineer who was on maternity leave. After that I spent one semester as a secondary school teacher in Vantaa. That was a rather colorful experience, but both myself and all the children eventually escaped unscathed. I saw it wise to return to science however, and subsequently joined European Commission's Joint Research Centre (Geel, Belgium) performing neutron scattering experiments. At JRC Geel we collaborated widely with other European research institutes, such as IFIN-HH (Bucharest, Romania), IPHC (Strasbourg, France), HZDR (Dresden, Germany), ENEA (Frascati, Italy), and ILL (Grenoble, France). In February 2021 I joined again the University of Helsinki as a senior laboratory engineer. My work here includes technical support and development of the nuclear spectrometers and the cyclotron, as well as teaching nuclear spectrometry and related topics. I am also the radiation safety officer and the nuclear materials responsible. And finally I am extremely happy to be a member of the RIP team, being able to take part in scientific research projects.