A U.S. Nuclear Regulatory Commission inspection last fall found TVA's Watts Bar Nuclear plant from November 2014 to August 2016 didn't follow orders to review whether actions against employees or contractors satisfied employee protection requirements or negatively affected the workplace.
In March 2016, the commission said the plant's perception was that operators can't raise safety concerns without fearing retaliation.
TVA settled in June, so the commission won't issue violations or civil penalties.
Among requirements, the commission says TVA has started an extensive review, hired safety culture consultants, and agreed to more communication, training and audits.
Changes also apply to Browns Ferry and Sequoyah nuclear plants, and corporate offices.