The discursive politics of nuclear waste: Rethinking participatory approaches and public perceptions over nuclear waste storage repositories in Switzerland

•Complementary perspective highlighting public opinions and their dynamics or stability.•Peoples' free reported arguments focus on values and responsibility.•Opponents and proponents use different arguments.•One third of the sample did not change their argumentation over time.•Discussion on the use of descriptive data for policy-making processes.

Used nuclear fuel must be safely disposed. One solution to this complex challenge are deep geological repositories. Participatory approaches accompany the selection of suitable sites for these repositories in many countries and have been studied by risk perception scholars. However, most research has used quantitative cross-sectional data to explain the relationships among the variables of interest (particularly risks) and to inform nuclear policies. In this paper, we introduce a complementary perspective highlighting two fundamental factors: public opinions and their dynamics or stability. We provide results of a longitudinal survey (2 measurements 1 year apart) on plans for a nuclear waste repository in Switzerland. The respondents (N = 841) submitted their own arguments with which they would discuss the site selection process. In addition, we surveyed the respondents' general opinions. We found a focus on values and responsibility. Those in favor of the repository used different arguments than those who opposed it or were undecided on it. Women perceived the repository more negatively (general opinion) but did not use different arguments than men. A comparison over time showed that one third of the sample did not change their argumentation. The use of descriptive data to enhance policy-making processes is discussed.