Speaker
Arturs Zarins
(Institute of Chemical Physics)
Description
Modified lithium orthosilicate pebbles with additions of titanium dioxide are suggested as an alternative tritium breeding ceramic for the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM). The tritium breeding ceramic in the HCPB TBM will be under the action of harsh operation conditions. Radiolysis can take place as a result, and unstable radiation-induced defects (RD) and radiolysis products (RP) can form. The formed RD and RP can interact with the generated tritium and may disturb tritium diffusion and hinder its release. In this research, the influence of the noble metal impurities (platinum, gold and rhodium which are introduced during the production process) on the radiolysis of the breeder pebbles was analysed.
High energy accelerated electrons were used instead of neutron irradiation to introduce radiolysis effects in order to avoid nuclear reactions and thereby the formation of radioactive isotopes. The samples were irradiated with accelerated electrons (E=5 MeV, D=12 MGy, T=300-345 K, dry argon). The irradiation parameters were selected, to accumulate mainly primary and secondary RD. The formation and accumulation of RD were subsequently analysed by electron spin resonance (ESR) spectroscopy. Also, the chemical composition, noble metal concentration and surface microstructure of the pebbles were studied.
Using ESR spectroscopy, the formation and accumulation of several paramagnetic RD were detected, such as E’ centres, HC2 centres etc. It was determined that the trace-impurities of the noble metals, with a sum content of up to 300 ppm, do not significantly influence the formation and accumulation of RD in the modified lithium orthosilicate pebbles.
Acknowledgment:
This research of the Baltic-German University Liaison Office was supported by the German Academic Exchange Service (DAAD) with funds from the Foreign Office of the Federal Republic Germany. The views and opinions expressed herein do not reflect those of the Baltic-German University Liaison Office.
Co-authors
Arnis Supe
(Institute of Chemical Physics, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia)
Arturs Zarins
(Institute of Chemical Physics, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia;The Faculty of Natural Sciences and Mathematics, Daugavpils University, Parades 1a, LV-5401, Daugavpils, Latvia)
Elina Pajuste
(Institute of Chemical Physics, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia)
Gunta Kizane
(Institute of Chemical Physics, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia)
Larisa Baumane
(Institute of Chemical Physics, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia;Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia)
Matthias Kolb
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany)
Mindaugas Andrulevicius
(Institute of Materials Science, Kaunas University of Technology, Barsausko street 59, LT-50131, Kaunas, Lithuania;Department of Physics, Kaunas University of Technology, Studentu street 50, LT-51368, Kaunas, Lithuania)
Oliver Leys
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany)
Oskars Valtenbergs
(Institute of Chemical Physics, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia;Faculty of Chemistry, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia)
Regina Knitter
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany)
Sigitas Tamulevicius
(Institute of Materials Science, Kaunas University of Technology, Barsausko street 59, LT-50131, Kaunas, Lithuania;Department of Physics, Kaunas University of Technology, Studentu street 50, LT-51368, Kaunas, Lithuania)
Vita Rudovica
(Faculty of Chemistry, University of Latvia, Jelgavas 1, LV-1004, Riga, Latvia)
