Experimental analyses are presented of fluctuations observed in a plasma-current-center, Ip-center, location and the inward clearance between the outermost flux surface and the first wall at plasma perturbations (e.g., βp collapse and disruption) for JT-60U divertor plasmas. The neutral point for vertical and horizontal movement of the Ip center at plasma disturbances is confirmed, and attachment of the plasma to the inward first wall is avoided because of the increase in li, at fast plasma-current quench. These experimental observations will support the design of fusion reactors like the International Thermonuclear Experimental Reactor (ITER).