Succumbing to the pressure of its debts, the Tennessee Valley Authority (TVA) has halted construction on three nuclear power plants, the only remaining incomplete plants in the nation. According to chairman Craven Crowell, TVA can no longer foot the bill alone. So far, TVA has invested about $4.6 billion in two unfinished units at the Bellefonte Nuclear Plant in Alabama, and $1.7 billion in Watts Bar 2 in Tennessee. TVA estimates it will cost as much as $8.8 billion to finish all three units. (The Bellefonte units are 88 percent and 57 percent complete, respectively.