Oklo said Tuesday that OpenAI CEO Sam Altman was stepping down as chairman of its board and indicated a partnership with the artificial-intelligence company could be on the horizon. Altman, who has served as chairman since 2015,

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

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.