sentences:  With the help of attorney Wendell Willkie, TEPCO challenged the constitutionality of the TVA Act in federal court.In 1939, however, the U.S. Supreme Court handed down its decision in "Tennessee Electric Power Company v. TVA" in which they upheld the TVA Act, and a few months later, TEPCO was forced to sell most of its assets, including Hales Bar Dam, to TVA for $78 million.After gaining control of Hales Bar Dam in 1939, TVA carried out extensive repair work on the dam's foundation that by 1943 had succeeded in halting the dam's leakage.