Georgia Power Co.’s studying whether to build a nuclear power plant on the Chattahoochee River in South Georgia drew harsh criticism in the Georgia Water Coalition’s sixth annual “Dirty Dozen” report released Wednesday. The report says such a facility would further burden the river at the heart of the 26-year-old water wars between Georgia, Florida and Alabama. And it would “produce radioactive waste for which our federal government has still not developed a permanent and safe disposal plan.”