Inside the secret plan to re-open Americas most infamous nuclear power plant code named Tetris

The mastermind behind the plan to reopen the nuclear plant that caused Americas worst reactor accident hatched the idea after learning tech CEOs were desperately searching for energy to power artificial-intelligence.

Constellation Energy and Microsoft announced a power purchase agreement in September to reopen the Three Mile Island (TMI) nuclear plant in Pennsylvania.

The plant is home the worst commercial nuclear power accident after the Unit 2 reactor suffered a partial meltdown due to mechanical failure and human error in 1979. 

Joe Dominguez, the chief executive of Constellation Energy, said he came up with the idea after OpenAI co-founder Sam Altman revealed data centers for some AI models would require as much power as a large city during a gathering for CEOs in May 2023. 

My first reaction is, "Wow, these guys are going to be in for a rude awakening about how much power is actually going to be available," Dominguez told The Wall Street Journal. It was like a lightning bolt hit me. 

Constellation Energy and Microsoft announced a power purchase agreement in September to reopen the Three Mile Island (pictured) nuclear plant in Pennsylvania

Joe Dominguez (pictured), the chief executive of Constellation Energy, said he came up with the plan after learning tech CEOs were searching for energy to power artificial-intelligence

The most advanced AI models are projected to need five gigawatts of power, as much as five nuclear reactors, and there is nowhere in the U.S. where it will be easy to connect data centers of that magnitude, according to WSJ.

Constellation executives code named the project Tetris - after the videogame - and quickly launched into researching how they could meet the energy demand tech CEOs needed.

Dominguez said he told colleagues, Saddle up. I want to understand within five weeks whether we could do this. 

Constellations engineers determined that a restart of Three Mile Island could be possible.

The Unit 1 reactor located on TMI Unit 2 was shut down in 1979 after its partial meltdown. Its twin - the Unit 2 rector - was operating until 2019.

To restart Unit 2, Constellation will invest $1.6 billion in the turbine, generator, main power transformer and cooling and control systems.

Then Dominguez had to get Pennsylvania Gov. Josh Shapiros support for the move. The two met for the first time last December and the CEO said Shapiro questioned him on the plant conditions and if a restart could be done safely without cost to the state.

Three Mile Island is home the worst commercial nuclear power accident after the Unit 2 reactor suffered a partial meltdown due to mechanical failure and human error in 1979

The Unit 1 reactor located on TMI Unit 2 was shut down in 1979 after its partial meltdown. Its twin - the Unit 2 rector - was operating until 2019

He grilled me, literally grilled me for well over an hour, maybe an hour and a half, Dominguez said.

Once he earned the governors support, Dominguez started to search for a corporate client.

Noelle Walsh, Microsofts corporate vice president of cloud operations and innovation, told WSJ the deal made sense because it would bring a large amount of reliable, carbon-free power to market more quickly and cheaply than other options.

If we had walked from the deal, Im sure somebody else would have stepped in, Walsh said.

The companies have not released the financial details of the deal, but analysts at Jefferies estimate Microsoft will pay between $110 to $115 per megawatt hour of electricity. 

The plant is expected to start delivering energy in 2028 under the agreement, and Constellation said they will pursue license renewal that will extend plant operations to at least 2054.