J. Clay Sell (born April 28, 1967) is the CEO of X-energy, a U.S. based, privately owned company that develops small modular nuclear reactors and advanced fuel technology (HALEU) for clean energy generation.

[1] Sell previously served as United States Deputy Secretary of Energy in the George W. Bush administration from March 21, 2005,[2] until he resigned, effective February 29, 2008.

Sell launched his career working as senior staff for the future House Armed Services Committee Chairman Mac Thornberry, from 1995 to 1999.

Additionally, Sell worked directly for the Chairman of the Appropriations Committee, Senator Ted Stevens, in his role as Majority Clerk and Staff Director for the Energy and Water Development Subcommittee[4] from 2000 to 2003.

In 2004 Sell worked again as a Special Assistant to the President for Legislative Affairs,[6] with a focus on the United States Senate agenda for energy, natural resources and budget appropriations.