It has nothing to do with economics, nuclear energy is stagnant because the industry is a regulatory hell. From eia.gov:
Of the 104 operating nuclear power reactors in the United States:
The last construction permit for a nuclear power plant was issued in 1978 for Progress Energy Inc.'s Shearon Harris plant, near Raleigh, North Carolina.
The last operating license for a nuclear power plant was issued in 1996 to the Tennessee Valley Authority's Watts Bar Unit 1, near Spring City, Tennessee after initial construction began in 1973.
Of the 104 operating nuclear power reactors in the United States:
The last construction permit for a nuclear power plant was issued in 1978 for Progress Energy Inc.'s Shearon Harris plant, near Raleigh, North Carolina.
The last operating license for a nuclear power plant was issued in 1996 to the Tennessee Valley Authority's Watts Bar Unit 1, near Spring City, Tennessee after initial construction began in 1973.