A tour of the Three Mile Island nuclear power plant interior.

• Microsoft will purchase power from Three Mile Island's Unit 1, which will be restarted by Constellation Energy in 2028.
• The plant will be renamed the Crane Clean Energy Center.
• The control room, turbine deck, and cooling towers of the plant are being examined.

The nuclear power industry is experiencing a major turnaround, with operations at Three Mile Island set to restart in four years, following a wave of plant closures.

The Three Mile Island Unit 1 reactor, which began operation in 1974, was permanently shut down in 2019 due to economic pressure as nuclear power struggled to compete against natural gas. However, the growing demand for technology is revitalizing the industry.

The tech company has agreed to restart Unit 1 of its data centers by purchasing the Crane Clean Energy Center, which was previously owned by Exelon. The plant's restart is subject to approval by the Nuclear Regulatory Commission.

Despite being shut down five years ago, Unit 1 of the Department of Energy operated safely and efficiently. However, it is located near the site of the worst nuclear accident in U.S. history. Meanwhile, Unit 2 reactor suffered a partial meltdown in 1979 and has not operated since the accident. It is currently being decommissioned by its owner, Energy Solutions.

The restoration of Unit 1, as stated by Constellation's chief generation officer, Bryan Hanson, will primarily entail routine maintenance tasks.

The main control room, turbine deck, and cooling towers of the plant are featured in this look. For more information on the restart, click here.

Main control room

Turbine deck

Cooling towers

— CNBC's Danielle DeVries contributed to this report.