Thomas Mason, former director of the Oak Ridge National Laboratory and current Battelle vice president, will become director of the Los Alamos National Laboratory on Nov. 1, after Triad National Security takes over management of the storied nuclear-weapon facility in New Mexico.

Mason is Triad’s president and CEO, making him ultimately responsible for Los Alamos’ nuclear stockpile stewardship and weapons modernization missions under a lab management and operations contract worth more than $20 billion over 10 years, including options.

Mason left Oak Ridge in 2017 after 10 years as director of the lab and president and chief executive officer of Oak Ridge prime contractor UT-Battelle. He returned to the parent company Battelle as senior vice president for laboratory operations.

Mason will replace Terry Wallace of incumbent lab-manager Los Alamos National Security, which will turn over the keys to Triad after 12 years on the job. Wallace himself has been lab director for less than a year; in January, he replaced Charles McMillan, who retired after six tumultuous years that were marred by safety and management lapses that ultimately led the National Nuclear Security Administration (NNSA) to put the lab management contract back on the street nearly a decade earlier than planned.

Los Alamos National Security’s management and operations contract was set to run out Sept. 30. An NNSA spokesperson in Washington, D.C., did not immediately reply to a request for comment about whether the incumbent had received an extension.

Triad announced four other senior management appointments at Los Alamos, all of which will be official Nov. 1. These include:

  • Robert Webster as deputy director of weapons. Webster, a longtime nuke man with a history at Los Alamos and NNSA headquarters, is already the lab’s principal associate director for the weapons program under Los Alamos National Security.
  • John Sarrao as deputy director of science, technology, and engineering. Sarrao took over this year as principal assistant director of the lab’s Science, Technology, and Engineering branch under the incumbent.
  • Kelly Beierschmitt as deputy director of operations. Beierschmitt, another Oak Ridge alum, is currently deputy laboratory director for science and technology and chief research officer at the Idaho National Laboratory for Battelle Energy Alliance: the Idaho lab’s prime contractor.
  • Frances Chadwick as the lab’s staff director. Chadwick is currently Los Alamos’ program director for weapons infrastructure in the principal associate directorate for the lab’s weapons program.