Mental models and social acceptability: Social acceptability of the radioactive waste repository, even for the low and intermediate radioactive waste (LILW), presents a great problem in every country with such a waste. Even if people agree with the need for its construction, the chosen location should be far from their homes (NIMBY). The reasons for such attitudes were attributed to different causes: uneducated public, differences in understanding of radioactivity and risk by experts and lay public, risk communication problems, lack of credibility and social trust, etc. Nowadays it is realized that public trust is extremely important if effective risk communication and public acceptability is to be achieved. It is also recognized that lay public mental model differ from expert ones and influence their attitudes towards different issues connected with nuclear energy. In this research relative influence of mental model on social acceptability in comparison with some other factors (like credibility, trust, demography…) is studied Search for LILW repository location: In 1996 the Slovenian national Agency for radwaste management - ARAO re-initiated the search for a LILW repository location with a new, so-called combined approach to the site selection. In this context the influence of social models on acceptability was studied. Previous research on people’s perception of the LILW repository construction, their attitudes towards radioactive waste, their willingness to accept it, based on several surveys, indicated significant differences in answers of experts and lay persons, mainly regarding evaluation of the consequences of repository construction. These findings support the use of mental models approach. Mental models approach: Based on the findings of pilot investigations a mental model approach to the radioactivity, radioactive waste and repository was used as a method for development of risk communication strategies with local communities which volunteered to host the repository. The mental models were obtained by adjustment of the method developed by Morgan and co-workers (Risk Communication, 2002) where expert model of radioactivity is compared with mental model of lay people obtained through individual opened interviews. Additional information on trust and role of main actors in the site selection process was gained with the overall questionnaire on the representative sample of Slovenian population. Variables influencing acceptability: While project is still under way some preliminary results clearly show that mental models ad least partially influence people attitudes towards LILW repository. Credibility of main players and other social issues are also important. Results of this study will provide information of relative importance of mental models in comparison with different social variables. A model of risk communication strategy based on the research findings is also prepared.