Leadership Team

Thomas (Thom) Mason is the President and CEO of Triad National Security, LLC (Triad) and serves as the Director of Los Alamos National Laboratory. Most recently he was the Senior Vice President for Global Laboratory Operations at Battelle where he had responsibility for governance and strategy across the six National Laboratories that Battelle manages or co-manages. Prior to joining Battelle, Thom worked at Oak Ridge National Laboratory (ORNL) for 19 years, including 10 years as the Laboratory Director. Under his leadership, ORNL saw significant growth in programs, new facilities, and hiring while achieving record low safety incident rates. Before becoming Laboratory Director, he was Associate Laboratory Director (ALD) for Neutron Sciences, ALD for the Spallation Neutron Source (SNS), and Director of the Experimental Facilities Division. During his time in Oak Ridge, Thom was active in the community serving as Chair of the Oak Ridge Public Schools Education Foundation as well as Innovation Valley, the Knoxville-Oak Ridge area regional economic development organization. He moved to ORNL from the University of Toronto where he was a faculty member in the Department of Physics and previously worked as a Senior Scientist at Risø National Laboratory and a Postdoc at AT&T Bell Laboratories. For the past 30 years, he has been involved in the design and construction of scientific instrumentation and facilities and the application of nuclear, computing, and materials sciences to solve important challenges in energy and national security. Thom has a Ph.D. in Experimental Condensed Matter Physics from McMaster University and a BSc in Physics from Dalhousie University. 

Robert (Bob) Webster serves as the Deputy Director Weapons at Los Alamos National Laboratory (LANL). In this role, Bob will have direct line management responsibility for planning, coordinating, and integrating the Weapons Program, particularly for the directorates of Weapons Engineering, Weapons Design and Weapons Production. Bob is a 29-year veteran of the Weapons Program at LANL and a recognized leader in Stockpile Stewardship. He began his laboratory career as a graduate student at LANL in 1984, becoming a consultant, then a technical staff member, and advancing through multiple national security positions to his present position: Principal Associate Director for Weapons Programs where he integrates the key capabilities of three associate directorates – Plutonium Science and Manufacturing (ADPSM), Weapons Physics (ADX), and Weapons Engineering and Experiments (ADW). During Bob’s tenure, the weapons program has consistently met or exceeded overall performance expectations and made significant contributions to LANL and NNSA missions—a compelling record of achievements that he brings to the many challenges of serving as the Deputy Director Weapons. Bob received a Ph.D. and M.S. in Nuclear Engineering from Purdue University, and a M.S. in Electrical Engineering and Applied Physics and a B.S. in Electrical Engineering from Case Western Reserve University. 

Dr. Mark Chadwick currently serves as the interim Deputy Director for Science, Technology & Engineering at Los Alamos National Laboratory. He was most recently the chief scientist and chief operating officer for the Associate Laboratory Directorate for Weapons Physics.

Chadwick is a nuclear physicist who has worked at Los Alamos for 33 years across both the DDSTE and Weapons organizations. He is a Laboratory Fellow, American Physical Society Fellow, American Nuclear Society Fellow, and recipient of DOE’s 2011 E.O. Lawrence Award.

He obtained his bachelor’s and doctorate degrees in physics from Oxford University.

Kelly Beierschmitt serves as the Deputy Director Operations of Los Alamos National Laboratory (LANL). Kelly has worked more than 30 years in the service of critical DOE missions. Most recently, he was the Deputy Laboratory Director for Science and Technology and Chief Research Officer for Idaho National Laboratory (INL) where he had responsibility for setting the scientific and engineering agenda and overseeing the research, development, demonstration and deployment of the critical missions for the laboratory. Prior to joining INL, Kelly worked at Oak Ridge National Laboratory (ORNL) for 13 years where he served as Associate Laboratory Director for both the Neutron Sciences and the Nuclear Science and Technology Directorates. He also served as ORNL’s Director of Environment, Safety, Health and Quality. Kelly moved to Oak Ridge from the Pacific Northwest National Laboratory where he held several roles both in the sciences and support functions. Kelly began his career at the Pantex Plant, where he served as a nuclear explosives engineer, developed some of the earliest Safety Analysis Reports, retooled high explosives operations and developed one of the earliest Master Safeguards and Security Agreements. Kelly’s entire career has emphasized the synergistic integration of science, technology and engineering with operational excellence to ensure effective mission delivery in a wide array of research and development environments – ranging from forefront experimental research in physical sciences to developmental engineering requiring hazardous nuclear operations. Kelly has a Ph.D. in Industrial Engineering (Risk, Reliability Engineering) from Texas Tech University and a BSc in engineering mathematics from West Texas A&M University. He is a registered Professional Engineer, Certified Safety Professional in Comprehensive Practice, and a member of the American Nuclear Society, Materials Research Society, and other professional societies. 

Laboratory Staff Director Frances Chadwick supports the Lab’s director and deputy directors and manages the Director’s Office and the six divisions that report into it. These include the Office of General Counsel, Communications and External Affairs, Ethics and Audit, the Office of Counterintelligence, the Community Partnerships Office, and the Office of National Security & International Studies. In this role, Frances is the executive champion for the Lab’s relationship with the communities of Northern New Mexico. She is also the Lab’s liaison with the Triad National Security, LLC Board of Directors, chaired by former Lab Director Michael Anastasio.

Frances has worked at the Laboratory since 1996 in various positions in Finance and Infrastructure. In her previous role, she managed the Lab’s portfolio of mission-critical facilities as program director for Weapons Infrastructure in the Weapons Directorate. In this role she also served on the Department of Energy’s Infrastructure Executive Council as the representative from NNSA sites and was the Lab’s lead for collaborations with the United Kingdom’s Atomic Weapons Establishment in the area of Infrastructure and Operations. Prior to this, Frances was the business manager for Weapons Programs, overseeing all financial, planning, and procurement activities. She is nationally recognized for her effective advocacy for excellence in support services to the mission, and in enabling the successful planning and solid financial support for the Lab’s mission-critical facilities.

Frances serves on the Laboratory’s Benefits and Investments Committee and is a board member of the Los Alamos Community Foundation. Frances is the executive champion for the Lab’s African American Employee Resource Group, and is a strong advocate for working parents. Originally from the U.K., Frances holds a bachelor’s degree from Oxford University, England, and an MBA from the University of California, Davis Graduate School of Management.

Charles W. Nakhleh is the Associate Laboratory Director for Weapons Physics (ALDX) at Los Alamos National Laboratory. In this role, he has line responsibility for the nuclear weapons designers and simulation code architects at the Laboratory, as well as program responsibility for the NA-11 weapons science, computing, and technology maturation portfolio. Prior to taking on his current role, he was the Executive Officer to the Deputy Director for Weapons (DDW), where he was responsible to the DDW for integrating and aligning activities across the weapons program. From 2013 to 2018, he was the Division Leader of the X-Theoretical Design Division (XTD) at Los Alamos National Laboratory. As the XTD Division Leader, he oversaw nuclear weapon physics design, assessment, and certification efforts at the Laboratory. Before returning to Los Alamos, he led the Inertial Confinement Fusion (ICF) Target Design Department in the Pulsed Power Sciences Center at Sandia National Laboratories. At Sandia, he led theoretical design and analysis efforts for magnetically-driven ICF and radiation-effects targets for the Z pulsed-power facility and indirect-drive experiments for the National Ignition Campaign (NIC). Before joining Sandia, he served as Group Leader (acting) and Deputy Group Leader for the Thermonuclear Applications Group in the Applied Physics (X) Division of Los Alamos. He spent nearly a decade before that as a staff member in X Division, where he served as a weapon system point-of-contact, worked extensively on uncertainty quantification, and made significant contributions to a wide variety of weapons physics and design issues. Charlie is a graduate of the Theoretical Institute of Thermonuclear and Nuclear Studies (TITANS) program at Los Alamos. He has served on a wide variety of advisory panels, including as a founding member of the NNSA’s Predictive Science Panel, a consultant to JASON, an adviser to the Undersecretary of Energy for Science on the NIC, and as an adviser to the NNSA on a variety of weapons physics issues. He received his Ph.D. in Physics from Cornell University in 1996. 

James Owen will serves as the Associate Laboratory Director, Weapons Engineering for Los Alamos National Laboratory. James has worked in LANL’s Nuclear Weapons Program for more than 25 years and is a recognized leader across the Nuclear Security Enterprise (NSE). He has demonstrated technical and program leadership abilities in successfully executing some of NNSA and DoD’s most significant and challenging nuclear weapon programs, including the B61 Alt 357, W80 LEP, W76-1/Mk4A LEP, B61-12 LEP, W88 Alt 370 and W88 Alt 940. In his current role as Associate Director for Weapons Engineering and Experiments, James manages the operations and infrastructure of High Explosives (HE) science and engineering research/development across 21 square miles, which are critical to LANL’s execution of nuclear weapons mission. A native of northern New Mexico, James began working at LANL as a high school summer student and participated in the Graduate Research Assistant program before becoming a full-time staff member. James earned a M.S. in Engineering from the University of Colorado at Boulder and a B.S. in Mechanical Engineering from New Mexico State University. 

John Benner is the associate Laboratory director for Weapons Production (ALDWP) at Los Alamos National Laboratory. In this role, he has responsibility for the production and evaluation of plutonium pits, nuclear weapon detonators, and other nonnuclear components. ALDWP also oversees plutonium processing and disposition, manufacturing of power supplies for NASA deep space missions, surveillance, nuclear materials management, and waste operations.

Prior to taking on his current role, Benner was the executive officer to the deputy Laboratory director for Weapons (DDW). He was responsible to the DDW for integrating and aligning activities across the weapons program.

From 2012 to 2017, Benner served as the Laboratory’s associate director for Weapon Engineering and Experiments (ADW) and chief engineer for Nuclear Weapons. In these roles, Benner led all weapons engineering, explosive science, and testing activities at the Laboratory. He oversaw the management and execution of weapons modernization activities and the management of support for Los Alamos stockpile systems.

From 2006 to 2012, Benner served as the Weapon Systems Engineering (W) Division Leader, responsible for all weapons engineering activities at Los Alamos, including assessment, refurbishment, certification, and supporting R&D for Los Alamos–designed systems in the enduring stockpile.

From 2002 to 2006, Benner led the W76-1 life extension program at Los Alamos during development engineering and into production engineering.

From 2019 to 2020, Benner was a senior technical advisor to the deputy administrator for Defense Programs at NNSA headquarters in Washington, D.C. From 2017 to 2019, Benner was the vice president and chief operating officer for MSTS, the management and operating contractor for the Nevada National Security Site (NNSS). In this role, he was responsible for operational and technical integration of all experimental activities across the NNSS site.

Benner holds a master’s of science degree in mechanical engineering and a bachelor of science degree in aerospace engineering from West Virginia University.

Nancy Jo Nicholas serves as Associate Laboratory Director, Global Security for Los Alamos National Laboratory. In this role, she leads the execution of programs in the areas of Defense Nuclear Nonproliferation, Nuclear Counter-Proliferation and Counter-terrorism, and Strategic Partnership Programs, as well as oversees the Field Intelligence Element. Nancy Jo has worked for LANL since 1990, currently serving as LANL’s Principal Associate Director for Global Security. Prior to this role, she was the Associate Director for Threat Identification and Response. Her expertise integrates national and international policies in nuclear nonproliferation and nuclear materials management with fast-paced innovations and technology development to address complex threats to global security. Nancy Jo serves on the National Academy of Sciences Nuclear and Radiation Studies Board and the Intelligence Science and Technology Experts Group. She is a Fellow of the Institute of Nuclear Materials Management (INMM), and recently served a two-year term as president of the INMM. She also recently served on the Board of Directors of the Vienna-based World Institute for Nuclear Security or WINS. She has a M.A. in Nuclear Physics from The George Washington University and a B.S. in Mathematics and Physics from Albright College. 

Patrick (Pat) Fitch serves as the Associate Laboratory Director, Chemical, Earth and Life Sciences for Los Alamos National Laboratory. Most recently, Pat was the President of the Battelle National Biodefense Institute, LLC (BNBI) and founding Director of the National Biodefense Analysis and Countermeasures Center (NBACC). BNBI has managed and operated NBACC as a Federally Funded Research and Development Center for the Department of Homeland Security since its formation in 2006. Prior to joining Battelle, Pat worked at Lawrence Livermore National Laboratory for 22 years where he served as Program Leader, Division Leader, Center Director, and Acting Deputy Associate Lab Director leading ChemBio defense, genomics, biotechnology, engineering research, and health care technologies. Pat has a Ph.D. in Electrical Engineering from Purdue University and B.S. degrees in Physics and Engineering Sciences from Loyola College, Maryland. Pat’s recent research interests have been the application of genomics, host-pathogen biology, and biosafety to bioforensic analysis and threat characterization in biodefense. 

Irene Qualters serves as the Associate Laboratory Director for Simulation and Computation. She currently serves as a Senior Science Advisor in the Computing and Information Science and Engineering (CISE) Directorate of the National Science Foundation (NSF), where she contributes to strategic leadership in new directions for the CISE Directorate. In her nearly nine years at NSF, she has had responsibility for developing NSF’s vision and portfolio of investments in high performance computing, and has played a leadership role in interagency, industry, and academic engagements to advance computing. Irene also served on the Science and Technology Committee of the LLNS/LANS Board of Governors. Prior to her NSF career, Irene had a distinguished 30-year career in industry, with a number of executive leadership positions in research and development in the technology sector. During her 20 years at Cray Research, she was a pioneer in the development of high performance parallel processing technologies to accelerate scientific discovery. Subsequently as Vice President, she led Information Systems for Merck Research Labs, focusing on international cyberinfrastructure to advance all phases of pharmaceutical R&D. Irene has a M.S. in Computer Science from the University of Detroit and a B.S. from Duquesne University. 

Mark Anthony serves as Associate Laboratory Director for Plutonium Infrastructure (ALDPI) at Los Alamos National Laboratory. In this role, he oversees execution of the 30 pits-per-year mission through modernization of the TA-55 infrastructure and capabilities.

Mark has more than 32 years of experience leading complex technical organizations with significant fiscal and programmatic responsibilities, most recently at European Spallation Source (ESS), a $3.8 billion effort to build and operate the world’s most powerful neutron source for the European Research Infrastructure Consortium. In his role at ESS, based in Lund, Sweden, he served as Project Director and Deputy to the Director General responsible for delivery of the ESS Construction Project according to its baseline scope, schedule, and cost. Mark led divisions, subproject managers, and support teams in achieving project goals, especially acting to facilitate integration of work across the subprojects.

Prior to his role at ESS, Mark served as CEO for nuclear fuel and services at General Electric Hitachi Nuclear Energy responsible for approximately 10% of GE Nuclear Business and the EU region strategic direction for growth and order targets.

Mark served in the U.S. Marine Corps for four years after high school and was stationed at several places at Paris Island in South Carolina, Twentynine Palms in California, Okinawa Japan, and Camp Lejeune, North Carolina. Following his service with the Marines, Mark has a BSME from Penn State University and a master’s degree from Drexel University.

Steven started at Los Alamos National Laboratory in November 2022 as Associate Laboratory Director for Environment, Safety, Health and Quality.

He is leader and educator with a PhD in management and a combined 36 years of diversified experience in environment, safety and health leadership; operations; and project engineering/management at nuclear-capable facilities. He has worked at Brookhaven National Laboratory for 30 years, most recently as Associate Laboratory Director of Environment, Safety and Health. In the position, he is responsible for the operations of the ES&H Directorate, with 140 engineers and technical staff and an annual budget of about $36M.

Steven has significant experience in other leadership roles, including as manager of the Radiological Control Division at Brookhaven. In that role, he managed an annual budget of $7.5 million and guided the implementation of the Laboratory’s nuclear, radiological control, and protection programs. This involved extensive collaboration with the DOE Site Office and state and local regulators to set environment, safety and health strategic goals for Brookhaven’s radiological operations. As Integrated Safety Management Program Manager, he established BNL’s programmatic framework for implementing DOE’s Integrated Safety Management. He also worked as Brookhaven’s Waste Operations Manager, managing all aspects of BNL’s radioactive and hazardous waste management programs, including day-to-day Hazard Category 2 Nuclear, Decontamination and Decommissioning, and Environmental Restoration operations.

His early career was dedicated to the U.S. Navy, where he served as a Nuclear Electrical Operator responsible for the safe and efficient operation and maintenance of the reactor system and the electrical control and protection systems.

Steven graduated from University of Phoenix with a Doctor of Management in Organizational Leadership in 2011. His Master of Science degrees were earned from George Washington University in Project Management in 2004 and from the New York Institute of Technology in Energy Management in 1999. Steven also has a Bachelor of Science in Engineering Science and Liberal Arts from Regents College, and is a graduate of the Leadership for Senior Executives Program at Harvard Business School and the Battelle Laboratory Operations Leadership Academy (LOLA).

LeAnne Stribley serves as the Associate Laboratory Director, Business Management for Los Alamos National Laboratory. She has more than 35 years of multi-industry experience building and leading the finance, accounting, procurement, IT, and administration functions of public, private and nonprofit entities. Most recently, LeAnne worked at Oak Ridge National Laboratory as Director of Contracts. She also served as ORNL’s Controller and Director for Accounting Services. Before joining ORNL, LeAnne was the Executive Vice President for Administration and Senior Vice President for Finance and Controller with the Tennessee Valley Authority. In each of these roles, LeAnne focused on continuous improvement of service levels in support of mission organizations. LeAnne was very active in the Knoxville community, serving on multiple Boards, including Child and Family Tennessee (Board Chair), Knoxville Tourism Corp (Treasurer), Leadership Knoxville, The Central Business Improvement District (Treasurer), YWCA, and as Chair of the Smoky Mountain Region Combined Federal Campaign. She has a B.B.A. in Accounting from Texas Wesleyan University and is a licensed C.P.A. 

Bret Simpkins serves as the Associate Laboratory Director for Facilities and Operations at Los Alamos National Laboratory. Since 2014, Bret has been the Director of Facilities and Operations for Pacific Northwest National Laboratory (PNNL) where he was responsible for campus-wide facility strategic planning, projects and engineering, operations and maintenance, nuclear operations, and real estate management functions. Prior to this role, he served in a number of senior level positions at PNNL including Director of Nuclear Operations, Chief Operating Officer for the National Security Directorate, and Division Manager of Nuclear Science, Safety, and Nonproliferation. Bret has more than 30 years of experience, including management and leadership of large inter-disciplinary R&D, applied science, technology, and engineering activities and organizations. Topical areas impacted by his work include: directed energy weapons, nuclear reactor safety, safety and physical security of nuclear facilities and materials, nuclear weapons assembly/disassembly process safety, global security, nuclear arms control and nonproliferation. Bret received his M.S. in Nuclear Engineering and B.E. in Energy and Power Systems from the University of New Mexico. He is a registered Professional Engineer. 

Unica K. T. Viramontes serves as the Associate Laboratory Director for Defense Protection Program (ALDDPP) at Los Alamos National Laboratory.  ALDDPP enables the Laboratory to achieve its national security and science missions.  ALDDPP protects our special nuclear material, property, information, and personnel and provides expertise, support, and guidance in all areas of security, safeguards, and emergency management – from classification to personnel and physical security, hazard response, and nuclear material control and accountability.  The Program is also responsible for preventing and neutralizing threats to the Laboratory.

Unica is responsible for the leadership, management, oversight, strategic planning, and execution of ALDDPP portfolio.  Under Unica’s leadership and direction, she provides a strategic vision and planning for a Program to be “best in class” in the DOE/NNSA Security, Safeguards, and Emergency Management community.  The professionals under her leadership are committed to be accountable, to serve the Laboratory, and Nation.

Unica started her career at Los Alamos National Laboratory in 1998.  Throughout her 24-year career, Unica started as a High-School Coop student, has held roles of increasing responsibility in more than seven functional security and safeguards areas.  Prior to becoming Associate Laboratory Director, she served as Senior Director for the Defense Security Program providing strategic and technical leadership for Safeguards, Security and Emergency Management programs; Security Division Leader setting the Division’s direction to respond to evolving physical security threats and programmatic needs; and the Program Director for the Mission Assurance, Security, and Emergency Response where she provided technical leadership and management of the Program Office activities and program management support for all aspects of the Laboratory-wide security and safeguards program.  She was responsible for the development and growth of the program, by 25% in two years, increasing the annual operating budget to approximately $175M.

Unica holds a BA from the University of California, Berkeley and an MBA from the University of New Mexico Anderson School of Management.

David F. Teter is the associate Laboratory director for Infrastructure and Capital Projects (ALDICP), where he is responsible for the leadership, management, oversight, strategic planning and execution of the Laboratory’s portfolio of construction projects. In this role, Dave leads the integration of planning, management and execution of infrastructure projects across Los Alamos National Laboratory.

Dave has 26 years of professional experience in multiple roles across the Laboratory, including project, program and line management of large, complex and hazardous facilities. Prior to his current role, Dave served for two years as the director of the Weapons Infrastructure and Planning Office (WIPO) at LANL, where he was responsible for funding the operations, maintenance and modernization of the Lab’s nuclear, high explosive and specialized weapons facilities. Besides repairing and improving the lifespan of existing facilities, the office provides long-range planning for weapons facility modernization to meet future mission needs.

Dave joined LANL in 1996 as a post-doctoral researcher, after receiving his PhD from the University of Illinois. The following year, he became a technical staff member in MST-6, and built his career at the Laboratory around materials science. From 2012 to 2019, he was division leader of Materials Science & Technology (MST), where he supervised 280 employees. That work spanned high-hazard nuclear facility operations to fundamental materials science research and development. He was the recipient of Awards of Excellence for the Nuclear Weapons Program and Stockpile Stewardship Program in 1999, 2000, 2001 and 2004.

Dave is a recognized expert in materials science and advanced manufacturing, with more than 20 peer-reviewed publications and several classified publications, and has served on a number of review boards and advisory panels.