President Carter will name a close aide of Energy Secretary James R. Schlesinger to the vacant seat on the Nuclear Regulatory Commission, according to administration and congressional sources.

The NRC has been split 2 to 2 in recent months, delaying a number of key licenses sought by the nuclear power industry.

Yesterday the White House reportedly notified members of Congress that Carter intends to nominate John Ahearne, an Energy Department official who has had a major hand in formulating proposals for speeding up licenses and storing radioactive waste.

Established by Congress in 1974, the NRC is an independent regulatory agency that oversees nuclear health and safety. Carter's selection for the fifth seat has been watched closely by the nuclear electric power industry, environmentalists, and anti-nuclear groups because it is expected to be the swing vote on key decisions.

A recent 2-to-2 tie vote in effect refused a license to export 17,000 pounds of uranium to India. It was the first time the commission ever turned down a nuclear export request.

Chairman Joseph Hendrie and Commissioner Richard Kennedy often vote favorably on industry license requests, as they did on the application to export uranium to India's Tarapur reactor.

Commissioners Richard Gilinsky and Peter Bradford voted against the export license and, industry and environmental advocates say, are generally more skeptical of industry applications.

Congressional sources say that it is too early to speculate whether Ahearne's nomination will be readily approved, but the Senate Environment and Public Works Committee chaired by Jennings Randolph (D-W.Va.) is favorably disposed.

Last October the committee rejected 7 to 4, Kent F. Hansen, a Massachusetts Institute of Technology nuclear engineer who was Schlesinger's choice to fill the vacant seat. Hansen's nomination was killed because he lacked experience in regulation and was insensitive to nuclear safety and waste disposal questions, according to Sen. Gary Hart (D-Colo.).

Following Hansen's rejection, Schlesinger and nuclear industry lobbyists urged Carter to consider Goldie Watkins, a black woman and former Atomic Energy Commission official. Her name was taken out of the running, however, following pressure from Rep. Jonathan B. Bingham (D-N.Y.) and others in Congress who thought her qualifications inadequate and objected to Schlesinger's role in the nomination.

Ahearne, 43, Joined the administration's energy policy and planning staff after Carter entered the White House and worked on Schlesinger's closely knit group preparing the president's energy bill. He also played an important role in the staff work that led up to Carter's decision to cancel the controversial Clinch River breeder reactor last April.

Since then Ahearne has been named deputy assistant secretary for power applications in DOE.

A Princeton-educated physicist and former Defense Department weapons analyst, Ahearne also had a major role in formulating the administration's proposal on waste storage - including provisions for the industry to share costs - as well as speeding up the NRC licensing process.

Ahearne has won generally favorable marks from both the nuclear power industry and environmentalists for his work at DOE.