The board amended its staff’s plan and voted not to resume construction on Bellefonte until after another stop-and-start (reactor) project, Watts Bar 2, was up and running in Tennessee.

Watts Bar was, with Bellefonte, dropped in the ’80s, but the T.V.A. (went) back and finished the first unit there, Watts Bar 1, in 1996, making that plant the youngest of the 103 power (reactors) currently operating in the United States.

The board was told by the agency’s staff at the meeting on Thursday that the construction work done to date on Bellefonte 1 would (cost) about $1.6 billion at today’s prices. The agency said it had spent $2.5 billion on Bellefonte 1 and 2, which was originally envisioned as a twin-unit plant. The (agency) has spent hundreds of millions of dollars more (maintaining) and securing the site since then. Completion of unit one is expected to cost another $4.9 billion, the staff said.