Nuclear Plant Shutdown and Restart, and the Spatial Socio-Economic Structure of Kagoshima: A Three-Period PCA Study (2010–2014–2020)

This study examines the impact of the nationwide suspension of nuclear power plants following the 2011 Fukushima Daiichi accident, as well as the subsequent restart of the Sendai Nuclear Power Plant in Kagoshima Prefecture, on local socio-economic structures. Using municipal-level statistics for 2010, 2014, and 2020, we applied principal component analysis (PCA) and clustering techniques to extract the underlying patterns of regional socio-economic organization. In addition, difference-in-differences (DID) regression analysis was employed to evaluate the effects of plant proximity on municipal fiscal indicators. The findings reveal that in 2010, urban scale and plant location were the primary axes of differentiation; by 2014, however, the suspension accentuated demographic and fiscal vulnerabilities across municipalities. In 2020, even after the plant restart, the structure of urban dominance and peripheral stagnation persisted, with widening disparities. The DID analysis further suggests that the fiscal benefits of the restart were limited and unevenly distributed. This study contributes to the literature by quantitatively and spatially assessing the dynamic impacts of exogenous shocks on regional societies, while highlighting both the risks of nuclear dependence and the pressing policy challenge of mitigating regional inequality.