Nuclear startup X-energy raised $1 billion in its initial public offering yesterday, selling 44.3 million shares for $23 each, a hefty premium above the $16 to $19 per share it was seeking. Initially, the company had hoped to raise around $800 million.

The stock is expected to begin trading on Friday on the Nasdaq Exchange under the ticker XE.

X-energy is building small modular reactors capable of generating electricity or delivering heat to industrial processes. The company has a deal with Dow to provide heat and power to a chemical plant in Texas and another with Amazon to sell as much as 5 gigawatts of nuclear power by 2039. Amazon’s Climate Pledge Fund led X-energy’s Series C-1 round.

Nuclear startups like X-energy have been buoyed by surging demand for electricity from data centers and other parts of the economy that have been electrifying.

The company says its reactors will generate 80 megawatts of electricity. Each Xe-100 reactor is cooled by helium gas, which flows over billiard ball-sized “pebbles” that are packed with BB-sized TRISO fuel pellets. TRISO fuel, which contains a kernel of uranium wrapped in carbon and silicon, was developed years ago to be safer than existing fuel designs, though it hasn’t been widely used. X-energy says its fuel can withstand higher temperatures, helping to keep the fuel contained and reduce the potential of a meltdown.