Dissertation: A new licensing model for licensing small reactor units

M.Sc. (Tech) Kristiina Söderholm, in her dissertation in the field of nuclear safety, goes through the licensing of nuclear power stations from the viewpoint of safety and considering the means that project management offers.

Nuclear power plants are monitored by a nuclear safety authority, which in Finland is the Radiation and Nuclear Safety Authority STUK.  The authority sets safety requirements, compliance with which ensures, to that extent, the safety of nuclear power use. The process which is used to show that the safety requirements are complied with is known as licensing. In small modular reactors (SMR) the emphasis on this process is different from that in large reactor units. In her investigation, Söderholm proposes a change for the licensing process for small reactor units.

The investigation considers small modular reactors. Typically, one SMR contains many reactor modules. This special feature greatly influences the licensing of SMRs and the suitability or unsuitability of the current practice. In her dissertation research, she goes through the licensing practices of various countries and compares the suitability of these practices where small modular reactors are involved.

The power of small modular reactors is below 300 megawatts. The size class varies from very small concepts of a few MW to 300 MW concepts. The largest nuclear power plants that are built in the world belong to the 1600 MW category. The size of modular reactors is determined by taking into account all the plant's reactor modules. Modularity provides flexibility for the nuclear power station. Maintenance of modules one by one becomes possible, for example. Lately, some challenges to nuclear power plant projects, such as projects not meeting their deadlines, have shown the importance of the licensing process for the success of the entire project.

The new licensing model resulting from the research creates a base for possible international licensing of SMRs. It draws its starting points from the example of the aviation industry, among others. In the reactor concepts that the research targets, it is typically possible to separate the most critical part, from the viewpoint of nuclear safety, away from the rest of the plant. That part of the nuclear power plant is not dependent on external conditions, and can therefore be approved for several different plant sites.

The dissertation, "Licensing Model Development for Small Modular Reactors (SMRs) – Focusing on the Finnish Regulatory Framework" in the field of nuclear safety by Kristiina Söderholm, M.Sc. (Tech) will be examined at the Lappeenranta University of Technology on Friday, 27 September at 10 a.m. in room 1382.
Professor Marco Ricotti from Politecnico di Milano will be the opponent and Professor Riitta Kyrki-Rajamäki from Lappeenranta University of Technology the custos.

The dissertation has been published in the Acta Universitatis Lappeenrantaensis research series (number 528) of the university. ISBN 978-952-265-451-9, ISBN 978-952-265-452-6 (PDF), ISSN-L 1456-4491, ISSN 1456-4491. The dissertation is available for reading on the Lappeenranta University of Technology's LUTPub database at http://urn.fi/URN:ISBN:978-952-265-452-6. A printed version of the dissertation may be purchased from the Aalef bookstore, tel. +358 (0)44 744 5511 or kirjakauppa@aalef.fi

The doctoral candidate's personal information:
Name: Kristiina Söderholm
Year and place of birth: 1979 Jämsänkoski
Home municipality: Kerava
Education: Matriculation Examination, Jämsänkoski High School, 1998
M.Sc. (Tech), Tampere University of Technology, 2004
Nuclear safety engineer, TVO, 2004-2009
Licensing and safety manager, Fortum, 2009 ->

More information: Kristiina Söderholm, tel. +358 (0)40 5638062 kristiina.soderholm@fortum.com