ACRS Membership

The ACRS is composed of individuals with a wide variety of engineering expertise. The membership currently includes expertise in nuclear engineering, risk assessment, chemistry, facility operations management, severe accident phenomena, materials science and metallurgy, digital instrumentation and control systems, thermal hydraulic and heat transfer, and mechanical, civil, and electrical engineering. Consultants are engaged to provide technical assistance on specific issues when required. ACRS members are appointed for four-year terms and normally serve no more than three terms.

Committee Members

Select one of the following names for biographical information about that member:

Walter L. Kirchner, Chair has more than 50 years' experience in the field of nuclear reactor systems and technologies.  more

Gregory H. Halnon, Vice Chair is an independent nuclear industry consultant who has more than 40 years’ experience in the nuclear and utility industries. more

David A. Petti, Member-at-Large, brings more than 30 years’ experience in technology leadership and principal investigator of nuclear science and engineering materials-related technologies. more

Ronald G. Ballinger is a professor of nuclear science, materials science and engineering and is head of the H.H. Uhlig Corrosion Laboratory at the Massachusetts Institute of Technology (MIT). more

Vicki M. Bier is a professor emerita in the Department of Industrial and Systems Engineering and the Department of Engineering Physics at the University of Wisconsin-Madison.  more

Vesna B. Dimitrijevic has more than 40 years’ experience in the area of Probabilistic Risk Assessment (PRA), development and application. more

Craig D. Harrington has more than 40 years’ experience in commercial nuclear power, working on the resolution of wide-ranging plant-specific and broadly applicable industry issues. more

Robert P. Martin Dr. Robert P. Martin is a professional engineer who brings more than 30 years of experience. He has led and focused on deterministic and probabilistic safety analyses more

Thomas E. Roberts Mr. Thomas E. Roberts has more than 40 years' experience in the field of nuclear reactor systems and safety.  He spent 36 years as an engineer and engineering manager at Naval Nuclear Propulsion Program (NNPP) headquarters more

Matthew W. Sunseri is an independent nuclear industry consultant with more than 35 years’ experience in the safe operation of large commercial reactors.  more

See also the Committee Membership Lists Since 1957.
 

Walter L. Kirchner, Chair

Dr. Walt Kirchner has more than 50 years of experience in the field of nuclear reactor systems and technologies.  He began his career as a licensed reactor operator/engineering officer sailing on the N.S. Savannah, completed graduate studies in nuclear engineering at Massachusetts Institute of Technology, and then was hired as a technical staff member at the Los Alamos National Laboratory.  During his time at Los Alamos, he held group leader and division management positions in applied energy research and development, nuclear reactor design and safety, defense programs, construction project management, and Government relations.  He provided leadership in the development of small modular reactor designs for special applications, and the conduct of reactor safety reviews for the Department of Energy and the Nuclear Regulatory Commission.  He was a consultant to the President’s Commission on the Accident at Three Mile Island (Kemeny Commission).  At Los Alamos, and subsequently at Argonne National Laboratory, he advised Laboratory Directors on science and technology policy and programs in the Executive offices, the Department of Energy, other Federal agencies, and Congress.  While at Argonne, he also served as Chief Technologist for the Council on Competitiveness, and focused on advancing high-performance computer-based modeling and simulation for the manufacturing of clean energy technologies.  Dr. Kirchner’s technical expertise is in the areas of nuclear reactor design and safety, and thermal hydraulics. 

Dr. Kirchner earned a B.S. degree in Marine Engineering from the U.S. Merchant Marine Academy (Class of 1969), and M.S. and Ph.D. degrees in Nuclear Engineering from the Massachusetts Institute of Technology. 

Gregory H. Halnon, Vice Chair

Mr. Gregory H. Halnon is an independent nuclear industry consultant who has more than 40 years’ experience in the nuclear and utility industries.  He has held positions ranging from systems engineer and operations management to executive leadership at operating and decommissioned nuclear plants including Chief Nuclear Officer of Three Miles Island Unit 2.  Mr. Halnon has expertise in all aspects of nuclear plant operations as well as quality standards, security, maintenance and engineering processes.  He currently holds professional engineering licenses in two states and has held two Senior Reactor Operator licenses in his career.  He has led numerous industry groups in both engineering and regulatory areas as well as two industry consortiums for separate small modular reactor technologies.

Mr. Halnon is a graduate of the Senior Nuclear Plant Managers course from the Institute of Nuclear Power Operations, a past nuclear academic program evaluator for the Accreditation Board for Engineering and Technology and is a life member of the American Nuclear Society.  Mr. Halnon earned a B.S. degree in Engineering from the University of Central Florida with an emphasis on mechanical and thermal hydraulics.

David A. Petti

Dr. David A. Petti brings more than 30 years’ experience in technology leadership and principal investigator of nuclear science and engineering materials-related technologies.  His work included numerous lead and chief scientist positions at the US Department of Energy, Idaho National Engineering Laboratory, University of Idaho and the Phebus Facility at the Cadarache Nuclear Site in France.

Dr. Petti has expertise on large nuclear technology development projects with national and international impacts. He held positions as a Laboratory Fellow and Chief Scientist for Nuclear Science and Technology Directorate and Director Nuclear Fuels and Materials Division at Idaho National Laboratory (INL) and a Joint Appointment with the Massachusetts Institute of Technology (MIT).

Dr. Petti earned a B.S. degree, M.S. degree and Sc.D. degree in Nuclear Engineering from MIT.  He has published two book chapters and has peer reviewed numerous journal articles.  Dr. Petti is a recipient of numerous awards including the Lifetime Achievement Award for an INL Publisher.

Ronald G. Ballinger

Dr. Ronald G. Ballinger is a professor of nuclear science, materials science and engineering and is head of the H.H. Uhlig Corrosion Laboratory at the Massachusetts Institute of Technology (MIT).  His areas of specialization are materials selection, nuclear engineering systems, environmental degradation and life assessment of these systems.  In addition to the courses he has taught at MIT, Dr. Ballinger has also developed and taught several industrial courses on environmental degradation with EPRI and the Materials Aging Institute.

Dr. Ballinger earned a bachelor's in mechanical engineering from Worcester Polytechnic Institute. He earned master's degrees in nuclear engineering and materials science and a doctorate in nuclear materials engineering from MIT.  Dr. Ballinger is a member of several professional societies and has chaired the Materials Science and Technology Division of the American Nuclear Society.

Vicki M. Bier

Dr. Vicki M. Bier is a professor emerita in the Department of Industrial and Systems Engineering and the Department of Engineering Physics at the University of Wisconsin-Madison.  Her areas of specialization include risk analysis, decision analysis, and operations research.  She has more than 40 years’ experience in risk analysis for the nuclear power, chemical, petrochemical, and aerospace industries, as well as homeland security and critical-infrastructure protection. 

Dr. Bier is a past president of the Decision Analysis Society, a fellow of both the Society for Risk Analysis and the Institute for Operations Research and the Management Sciences, and the editor-in-chief of Decision Analysis.  She has served on the Radiation Advisory Committee, the Homeland Security Advisory Committee of the Science Advisory Board for the U.S. Environmental Protection Agency, and on several panels, committees, and boards for the National Research Council.  Dr. Bier earned a bachelor's in mathematical sciences from Stanford University and a doctorate in operations research from the Massachusetts Institute of Technology.

Vesna B. Dimitrijevic

Dr. Vesna B. Dimitrijevic has more than 40 years’ experience in the area of Probabilistic Risk Assessment (PRA), development and application. She was technical lead for AREVA's U.S. EPR Design certification.  As a technical expert, Dr. Dimitrijevic has participated in the development of diverse PRA methods: Risk Informed Applications for Generation 3 plants, EPRI Risk Informed Inservice Inspection, Internal Flooding and Fire PRA guidance.  She has provided leadership for over 30 risk-informed PRA applications, and for various PRA developments in numerous U.S. nuclear plants.  She served as an instructor in the Risk Informed PRA courses offered by the International Atomic Energy Agency and is one of the lecturers for the MIT graduate course on the integration of reactor design, operations, and safety. 

Dr. Dimitrijevic holds a B.S. degree in Electrical Engineering and a M.S. degree in Nuclear Engineering from the University of Belgrade, and a Ph.D. in Nuclear Engineering from the Massachusetts Institute of Technology.

Craig D. Harrington

Dr. Craig Harrington has more than 40 years’ experience in commercial nuclear power, working on the resolution of wide-ranging plant-specific and broadly applicable industry issues. His diverse background includes nuclear engineering and thermal sciences, materials degradation management, and the application of probabilistic methods to gain important safety insights. His career began with 23 years of direct nuclear power plant experience at Comanche Peak spanning plant construction, startup, operation, and licensing interactions, as well as extensive involvement addressing industry-wide issues. Since joining EPRI in 2006, Dr. Harrington has become a subject matter expert on primary water stress-corrosion cracking degradation management in pressurized water reactor primary system applications. He also co-led development of the xLPR (Extremely Low Probability of Rupture) probabilistic fracture mechanics code for EPRI with his counterparts at the NRC’s Office of Nuclear Regulatory Research. A recent area of focus for Dr. Harrington has been materials management issues in small modular reactors and developing approaches for addressing these in the design stage.

Dr. Harrington earned a B.S. in Nuclear Engineering, an M.E. in Mechanical Engineering, and a D.Eng. degree, all from Texas A&M University. He is a registered professional engineer in the state of Texas.

Robert P. Martin

Dr. Robert P. Martin is a professional engineer who brings more than 30 years of experience. He has led and focused on deterministic and probabilistic safety analyses, defining requirements and acceptance criteria, developing phenomenological identification and ranking tables, documenting and implementing best‑practices and quality program procedures, software development, commercial grade dedication and qualification, derivation of analytical techniques (e.g., scaling), verification and validation, compilation of design/model inputs, quantification of uncertainties and sensitivities, calculation of figures-of-merit, automation, and safety-basis documentation and defense before regulatory authorities.
 
Dr. Martin holds several patents, authored numerous publications and he built and performed safety analyses for pressurized and boiling water reactor power plants, integral and separate effects test facilities, and advanced reactor designs with passive safety systems. Dr. Martin has received multiple awards and honors, including American Nuclear Society Fellow in 2021 and Distinguish Former Student, Department of Nuclear Engineering, Texas A&M University in 2017. He is an ANS lifetime member. 
 
Dr. Martin holds a Ph.D. in Nuclear Engineering from Penn State University, as well as M.S. and B.S. degrees in Nuclear Engineering from Texas A&M University.

Thomas E. Roberts

Mr. Thomas E. Roberts has more than 40 years' experience in the field of nuclear reactor systems and safety.  He spent 36 years as an engineer and engineering manager at Naval Nuclear Propulsion Program (NNPP) headquarters, working in various roles in the Instrumentation and Controls (I&C) Division and then completing his career with 12 years as the Director of Reactor Safety and Analysis. During his tenure in the I&C Division, he provided overall technical direction in development of digital I&C systems for nuclear powered ships, as the Director of Reactor Safety and Analysis, he served as the principal advisor to the Director, NNPP, on nuclear safety for naval nuclear propulsion plants, laboratory fuel manufacturing facilities, refueling operations, and program fuel disposal facilities.  In addition, he also served as the principal spokesperson to the U.S Nuclear Regulatory Commission (NRC) and the Department of Energy on matters pertaining to reactor and special nuclear material safety.  Since retirement from the NNPP, Mr. Roberts has served as a subject matter expert in programs for advanced reactor development, including consulting in reactor safety and I&C for a transportable microreactor program and for a nuclear thermal rocket reactor concept. 

Mr. Roberts earned B.S. and M.S. degrees in Electrical Engineering from the University of Virginia.  He, along with his NNPP team, won a DOE Honor Award from the Secretary of Energy in April 2015 for efforts in support of a review by the US NRC of the reactor plant design for the FORD-class aircraft carrier.

Matthew W. Sunseri

Mr. Matthew W. Sunseri is an independent nuclear industry consultant with more than 35 years’ experience in the safe operation of large commercial reactors.  Prior to starting his own executive consulting practice, he was president and chief executive officer of Wolf Creek Nuclear Operating Corporation.  Mr. Sunseri has a wide range of experience in the operation, maintenance, engineering, oversight and security of the nation’s commercial nuclear power fleet.  He started his career as a nuclear engineer assigned to the construction, licensing, startup and operation of the Comanche Peak nuclear power plant.  Throughout his career, he has supervised, managed or provided oversight for activities at several commercial power stations.  Mr. Sunseri has served on philanthropic and corporate boards of directors and has been a member of the American Nuclear Society since 1979.

Mr. Sunseri earned his B.S. degree in Nuclear Engineering from Texas A&M University and is a graduate of the Advanced General Management Program at Northwestern University and the Directors Institute at Emory University.  Mr. Sunseri is a registered professional engineer in the state of Texas.