Constellation Energy Seeks Regulatory Help to Restart Three Mile Island Unit 1 Nuclear Plant by 2027

Constellation Energy is seeking regulatory assistance to restart Unit 1 of the Three Mile Island (TMI) nuclear plant in Pennsylvania, targeting a 2027 restart.

The Plan

• Plant: Three Mile Island, Unit 1
• Owner/Operator: Constellation Energy
• Target restart: 2027
• Current status: Decommissioned but infrastructure intact
• Requested support: Regulatory and policy assistance from authorities

Three Mile Island Context

TMI is infamous for the 1979 Unit 2 partial meltdown — the worst commercial nuclear accident in US history. However:

• Unit 1 operated safely from 1974 until its premature shutdown in 2019
• Unit 1 was unaffected by the Unit 2 accident
• The restart only involves Unit 1; Unit 2 remains permanently decommissioned
• Unit 1 was shut due to economic reasons, not safety

Why Restart Now?

AI-Driven Demand

The primary driver for restart:

• Microsoft signed a power purchase agreement (PPA) with Constellation for TMI's output
• The deal is part of Microsoft's AI data center energy strategy
• AI data centers require reliable, 24/7 clean power — exactly what nuclear provides

Economics Have Changed

• Carbon pricing makes nuclear more competitive vs gas
• Inflation Reduction Act provides nuclear production tax credits
• AI demand creates willing buyers at premium rates

Challenges

1. Regulatory hurdles — relicensing requires NRC approval
2. Workforce — reassembling a qualified nuclear workforce
3. Equipment aging — some components need replacement after 5 years idle
4. Public perception — overcoming the Three Mile Island stigma

Significance

Restarting TMI Unit 1 would be one of the most dramatic nuclear comebacks in history — literally bringing the world's most infamous nuclear plant back to life to power the AI revolution.