Oklo says its microreactors, called Aurora, have smaller and simpler designs that will range from 15 megawatts to as much as 100 megawatts or more.

Altman’s resignation opens up the opportunity for future deals between OpenAI and the nuclear-energy startup. Oklo shares fall after hours.

Sam Altman, the billionaire co-founder of OpenAI Inc., is stepping down from his role as chairman of Oklo Inc., clearing a path for the advanced nuclear company to more aggressively pursue deals to deliver clean energy to power-hungry artificial intelligence firms.