As the Democrats flip both the House and Senate in the midterm elections, the leadership of several committees will change drastically. 

As of Thursday evening, the Associated Press and other national media outlets have projected the Democrats to win more than 250 seats in the House and hold at least 54 seats. The new session of Congress will not begin until Jan. 3, 2027 and new chairs of committees will be selected by then. 

Here are some expected changes to occur in committees in both chambers concerning commercial nuclear power, defense-related nuclear and nuclear waste. 

House Energy and Commerce Committee

Under GOP leadership, Rep. Brett Guthrie (R-Ky.) led the full committee, with Rep. Frank Pallone (D-N.J.) being the ranking member. With the new Congress to start up in January, Pallone told Politico Wednesday he will seek to lead the full Energy and Commerce committee.

For the Energy subcommittee, Reps. Bob Latta (R-Ohio) and Randy Weber (R-Texas) were the chair and vice chair of the subcommittee that focused on nuclear power over the past two years. Rep. Kathy Castor (D-Fla.) was the ranking member of the subcommittee. While Castor won her reelection bid, Castor could pivot towards leading the Energy and Commerce’s health subcommittee in January 2027.

House Appropriations Committee

Rep. Tom Cole (R-Okla.) headed the full House Appropriations committee, with Rep. Rosa DeLauro (D-Conn.) as the ranking member. DeLauro said in a Wednesday local news interview that she anticipates taking over as chair of the full appropriations committee in the next Congress. 

In the House energy and water development and related agencies’ subcommittee, Rep. Chuck Fleischmann (R-Tenn.) was the chair and Marcy Kaptur (D-Ohio) served as the ranking member. Kaptur previously chaired this subcommittee from 2019 to 2022. 

While Rep. Mike Levin (D-Calif.) did not serve in a leadership role on the House Energy & Water subcommittee, won his reelection bid in California’s 49th district. Levin is a co-chair of the Spent Fuel Solutions Caucus with Fleischmann. 

House Armed Services Committee

The House Armed Services Committee is expected to be chaired by Rep. Adam Smith (D-Wash.) as he served as the ranking member the past two years. According to a Wednesday article from The Hill, Smith is asking for support to become the chair of the committee and plans to conduct much oversight on the Pentagon.

Smith intends to perform a full audit on the Pentagon, from the Iran conflict to the Latin America conflicts conducted, he said in a Thursday X post. Rep. Mike Rogers (R-Ala.) served as chair of the full committee over the past two years.

Senate Energy and Natural Resources Committee

The Senate Committee on Energy and Natural Resources, which oversees Department of Energy programs and development on public lands, is set to be led by Sen. Martin Heinrich (D-N.M.). Heinrich said in a Thursday interview some procedural things need to occur but will “likely” chair the committee. Sen. Mike Lee (R-Utah) chaired the full committee under GOP leadership these past two years.

Senate Appropriations Committee

The Senate Appropriations Committee could be chaired by Sen. Patty Murray (D-Wash.), Energy Communities Alliance (ECA) said in an email summary. Sen. Susan Collins (R-Maine) led the full committee under Republican leadership. But Collins was defeated by Democrat Troy Jackson, ending her Senate run which began in 2002. 

Murray could also chair the Senate energy and water development subcommittee, which was previously chaired by Sen. John Kennedy (R-La.). 

Senate Armed Services Committee

The ECA predicts the Senate Armed Services Committee will likely be chaired by Sen. Jack Reed (D-R.I.). Reed, who just clinched his sixth term in Senate these midterms, previously served as the chair of the committee from 2021 to 2025. Current committee chair Sen. Roger Wicker (R-Miss.) succeeded Reed to lead the committee under GOP leadership in 2025. Now he could potentially precede Reed in 2027. 

Senate Environment and Public Works Committee

The Senate Committee on Environment and Public Works, which oversees the Environmental Protection Agency, Nuclear Regulatory Commission and other programs, would likely be chaired by Sen. Sheldon Whitehouse (D-R.I.),  ECA said. However, law firm Holland & Knight said in a Thursday insight that it anticipates Whitehouse to chair the Senate Judiciary Committee, following the retirement of Sen. Dick Durbin (D-Ill.)

If Whitehouse chairs the judiciary committee, Holland & Knight said Sens. Jeff Merkley (D-Ore.) or Ed Markey (D-Mass.), who both won their reelection bids, could either chair the Senate Environment and Public Works Committee. Sen. Shelley Capito Moore (R- W.Va.),  who also won her reelection bid, previously chaired the committee under GOP leadership.