NEW : Nuclear regulator tours plants along the swollen Missouri River . Critical infrastructure has been protected at both plants , officials say . They have encroached on the idled Lake Calhoun plant . The still - operating Cooper plant is several feet above the river .
NEW : Nuclear regulator tours plants along the swollen Missouri River . Critical gear has been protected at both plants , officials say . Floodwaters have encroached on the idled Fort Calhoun plant . The still-operating Cooper plant remains several feet above the river .