Stephen Streiffer
Stephen Streiffer

Laboratory Director

Dr. Stephen K. Streiffer became the director of Oak Ridge National Laboratory (ORNL) on October 16, 2023. As the twelfth director in ORNL’s history, Streiffer leads more than 6,500 staff in delivering on critical national missions. Streiffer has served across the national laboratory complex in multiple research and leadership positions, including as interim director of SLAC.

Susan S. Hubbard
Susan S. Hubbard

Deputy for Science and Technology

Susan Hubbard guides one of the nation’s most extensive portfolios of research and development, spanning computing and computational sciences, materials science, environmental and biological research, energy science and technology, isotope research and development, fission and fusion energy, neutron sciences, and national security sciences. In concert with the Deputy for Laboratory Operations, she supports the Laboratory Director in the planning, integration, and execution of Laboratory-level initiatives.

Balendra Sutharshan
Balendra Sutharshan

Deputy for Operations

Deputy for Laboratory Operations Dr. Balendra Sutharshan coordinates overall operations and support functions at ORNL: facilities operations; environment, safety, and health; business operations; security; human resources; communications; and technology transfer. In concert with the Deputy Director of Science and Technology, Sutharshan supports the Laboratory Director in the planning, integration, and execution of Laboratory-level initiatives as ORNL’s chief operating officer.

Lindsey Twardy
Lindsey Twardy

Chief of Staff

Lindsey Twardy is Chief of Staff at Oak Ridge National Laboratory. In this role, she serves as an advisor to the Laboratory Director and helps to integrate leadership across ORNL to advance the Lab’s vision, fulfill mission objectives, and ensure operational effectiveness.

Brian Arrington
Brian Arrington

Chief Human Resources Officer

Chief Human Resources Officer Brian Arrington oversees the lab’s talent recruitment and retention along with HR operations, labor relations, and benefits. Arrington, a highly accomplished executive who is especially skilled in all aspects of successful human resources management and operations, joined ORNL in 2023. Arrington is committed to attracting and retaining top talent. He does this by creating a culture in which team members are empowered with the confidence needed to execute and to succeed.

J. Scott Branham
J. Scott Branham

Chief Financial Officer

Chief Financial Officer for UT-Battelle since April 2011, Scott received a B.S. from Concord College (now Concord University) and an MBA from Auburn University. He is also a certified public accountant. Before joining UT-Battelle as Chief Audit Executive in 2000, Scott served as Chief Audit Officer for Oak Ridge Associated Universities and as an auditor for the U.S. Department of Energy’s Office of Inspector General.

Jeremy Busby

associate laboratory director for Isotope Science and Engineering

Dr. Busby is the Associate Laboratory Director for the Isotope Science and Engineering Directorate at Oak Ridge National Laboratory. His technical contributions range from light water reactors to sodium reactors and space reactor systems as well as research in support of the ITER project.

Jens Dilling
Jens Dilling

Interim Associate Laboratory Director for Neutron Sciences

Jens Dilling, an experimental nuclear physicist and leader in the field of precision experiments for fundamental and applied nuclear physics, brings extensive experience to his role overseeing the neutron scattering and user research programs at the Spallation Neutron Source and High Flux Isotope Reactor.

John Gearhart
John Gearhart

Director, Environment, Safety, Health, and Quality

John Gearhart is the director of Environment, Safety, Health, and Quality (ESH&Q) at Oak Ridge National Laboratory. In this position, he leads the safety and operational infrastructure that enables the laboratory’s science missions while protecting workers, the public, and the environment. ESH&Q provides broad expertise and programs to support nuclear safety, promote occupational health, control work hazards, meet regulatory requirements, manage waste responsibly, and ensure quality performance.

Cynthia Jenks
Cynthia Jenks

Associate Laboratory Director for Physical Sciences

Cynthia Jenks stewards ORNL’s broad physical sciences portfolio, with particular emphases on quantum materials; structural materials and alloys; soft materials; nanoscience; and applications of materials and chemistry in energy and security.

David Keim Director of Communications
David Keim

Chief Communications Officer

As Chief Communications Officer, David is responsible for external and internal communications, community relations, and protocol visits for Oak Ridge National Laboratory.

Moe Khaleel
Moe Khaleel

Associate Laboratory Director for National Security Sciences

Dr. Moe Khaleel guides the research and development of science-based solutions to counter critical threats to public safety, national defense, energy infrastructure and the economy. Leveraging the broad science foundation at ORNL, he oversees the work of multi-disciplinary research teams with signature capabilities in nuclear and uranium science, high-performance computing, geographic information science, cyber security science and advanced manufacturing.

Paul Langan
Paul Langan

Associate Laboratory Director for Biological and Environmental Systems Science

As ORNL’s Associate Laboratory Director for Biological and Environmental Systems Science, Paul Langan stewards a research portfolio targeting the convergence of biology, ecology, engineering, data discovery, physical sciences, and computing to advance U.S. competitiveness in the global bioeconomy and Earth system sustainability.

David Mandl
David Mandl

General Counsel

David Mandl is the General Counsel at Oak Ridge National Laboratory and Secretary of UT-Battelle, LLC. He leads a team of legal professionals with broad expertise in all practice areas relevant to ORNL’s mission, and oversees the Lab’s Privacy Program, Ethics Program, Intellectual Property Management, and Corporate Governance.

Kathy McCarthy
Portrait – Kathy McCarthy. June 24, 2021.

US ITER Project Director

Kathy McCarthy joined the Oak Ridge National Laboratory (ORNL) in 2020 after three years as Laboratory Director and Vice President for Science and Technology for the Canadian Nuclear Laboratories, where she oversaw a staff of 650 and grew the labs’ commercial work. She previously held a variety of engineering and leadership roles at Idaho National Laboratory (INL), including Director of Domestic Programs in INL’s Nuclear Science and Technology Directorate, Director of the Light Water Reactor Sustainability Program Technical Integration Office, and National Technical Director for the Systems Analysis Campaign for DOE Office of Nuclear Energy’s Fuel Cycle R&D Program.

Graeme Murdoch
Graeme Murdoch

Director, Second Target Station Project

Graeme Murdoch is the interim project director for the Second Target Station. He has over 35 years of progressive experience working in technical and management capacities in a particle accelerator and fusion engineering environment. 

Tyler Owens
Tyler Owens

Federal Affairs Director

Tyler Owens is federal affairs director at ORNL. In this role, he serves as ORNL’s senior representative and chief liaison to government officials, industry, think tanks, and university representatives in Washington, D.C. He provides guidance to the laboratory director to develop and execute strategies that best position ORNL in the evolving federal policy environment. He is also responsible for presenting ORNL’s priorities to Congress, the administration, and federal agencies.

Fred Pieper

Chief Audit Executive

Fred, who has served as a chief audit executive for 14 years, leads the Internal Audit Directorate, which is responsible for all audit activities and the Employee Concerns Program at Oak Ridge National Laboratory (ORNL). The organization provides independent, objective assurance and consulting services to improve the effectiveness of risk management, internal control, and governance processes through evaluations of ORNL management systems, processes, and programs. The organization also provides an anonymous and confidential avenue for staff to raise concerns and oversees the investigation of those concerns.

Kris Torgerson
Kris Torgerson

Director of Information Technology Services

Kris Torgerson joined Oak Ridge National Lab in February of 2017 as Deputy Chief Information Officer and subsequently became Director of ITSD in October of 2017.  He was promoted to Chief Information Officer in September of 2018.  In this position, he is responsible for all commodity technology delivery as well as strategy, cyber security, and supports privacy program delivery for the Laboratory.

Georgia (Gina) Tourassi
Georgia (Gina) Tourassi

Associate Laboratory Director for Computing and Computational Sciences

Georgia (Gina) Tourassi is the associate laboratory director for Computing and Computational Sciences at Oak Ridge National Laboratory. Dr. Tourassi has decades of research leadership leveraging AI, big data, and high-performance computing for scientific breakthroughs, most recently serving as the division director for the National Center for Computational Sciences and director of the Oak Ridge Leadership Computing Facility (OLCF).

Mickey R. Wade

Associate Laboratory Director,

Fusion and Fission Energy and Science

Mickey Wade was named Associate Laboratory Director for the Fusion and Fission Energy and Science Directorate in April 2023. Before that, he served as Division Director for Fusion Energy for three years. Wade recently served as deputy director of the Magnetic Fusion Energy Division for General Atomics and has extensive experience in fusion energy research, programmatic development, and strategic planning.

Robert Wagner
Robert Wagner

Associate Laboratory Director,

Energy Science and Technology

Dr. Robert Wagner is the Associate Laboratory Director of the Energy Science and Technology Directorate at Oak Ridge National Laboratory. In this role, he leads more than 450 researchers, technical professionals and other staff focused on developing and deploying advanced technology solutions in manufacturing, buildings, transportation, and electrical grid infrastructure.

Ann Weaver
Ann Weaver

Director of Facilities and Operations

Ann Weaver manages seven divisions that provide critical laboratory support services. These include facilities management, laboratory protection (security, fire protection, emergency preparedness, and emergency management), engineering and construction management, materials fabrication, instrumentation, site services, logistical functions, and craft services. In addition, the Facilities and Operations Directorate includes laboratory modernization and facilities strategic planning functions.