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Membership - Texas Radiation Advisory Board

Board Membership Requirements

The statutes state the membership requirements for the Texas Radiation Advisory Board's 18 members, based on categories each member is to represent. Members serve 6 year terms. The board is composed of:

  • One representative from industry who is trained in nuclear physics, science or nuclear engineering
  • One representative from labor
  • One representative from agriculture
  • One representative from the insurance industry
  • One individual who is engaged in the use and application of nuclear physics in medicine
  • One hospital administrator
  • One individual licensed by the Texas State Board of Medical Examiners who specializes in nuclear medicine
  • One individual licensed by the Texas State Board of Medical Examiners who specializes in pathology
  • One individual licensed by the Texas State Board of Medical Examiners who specializes in radiology
  • One representative from the nuclear utility industry
  • One representative from the radioactive waste processing industry
  • One representative from the petroleum well-servicing industry
  • One health physicist
  • One individual licensed by the State Board of Dental Examiners
  • One representative from the uranium mining industry
  • Three representatives of the public

For more detailed information on board membership requirements, required training, standards of conduct, duties, and powers, please see Texas Health and Safety Code Chapter 401.

Current Board Members

Board Member Name Background Term Expiration Address and Telephone

 Doug Posey, D.V.M.

 Doug Posey, D.V.M., is a private practice owning veterinarian in south Texas. He is a 1995 Graduate of Texas A&M University College of Veterinary Medicine. He has been in private practice for 25 years, with an interest in small animal medicine and surgery. Prior to general practice, he founded and operated the first animal emergency clinic in Corpus Christi. 

Dr. Posey has also served in an Adjunct Professor capacity at Texas A&M University- Corpus Christi from 1998-2010, where he taught Nutrition, Anatomy & Physiology, Medical Terminology, Pathology, and Toxicology. While serving in that capacity, he also oversaw and approved the IACUC and OLAW approved research projects, as it related to research and animal welfare compliance.

Dr. Posey has served in the past on both the Board of Directors, and as an Executive Director, for the Texas Veterinary Medical Association (TVMA), and is an active member of the American Veterinary Medical Association. He has also held the post of President of the Coastal Bend Veterinary Medical Association.

Dr. Posey considers himself a perpetual student of the guitar, and his other hobbies include membership in the Aircraft Owners and Pilots Association, and the Oldsmobile Club of America.

 Robert (Bob) Redweik

Bob Redweik

Representing the Oil and Gas Industry.  Appointed to the Board in 2019 by Governor Greg Abbott.

Mr. Redweik is the Director of EHS/Regulatory for Citation Oil & Gas Corp.  Citation is a privately held exploration and production company with onshore operations in 13 states in U.S. mid-continent area stretching from Montana to Texas and from Indiana to Utah.  Mr. Redweik has over 40 years of experience in environmental and regulatory compliance and health and safety including the handling, transportation, and disposal of naturally occurring radioactive materials (NORM).

Mr. Redweik started his oil and gas career with Shell Oil Company as an environmental engineer and has worked both onshore and offshore operations.  He has represented Shell and the oil and gas industry on various American Petroleum Institute committees, oil and gas association committees, and the Groundwater Protection Council and was a prior member of the Society of Petroleum Engineers. 

Mr. Redweik is a 1980 graduate of Purdue University with a B.S. degree in Civil Engineering and an MBA from Loyola University, New Orleans, in 1985.

Kenneth (Ken) Peters

Ken Peters

Representing the Nuclear Utility Industry.  Appointed to the Board in 2019 by Governor Greg Abbott.

Mr. Peters is the Senior Vice President and Chief Nuclear Officer for Vistra Energy/Luminant.  Luminant is a competitive power generation subsidiary of Vistra Energy.  In his role as Chief Nuclear Officer, Mr. Peters is responsible for directing the safe, reliable and cost-effective operation and maintenance of the Comanche Peak nuclear power plant (CPNPP).  

In addition to providing strategic direction of CPNPP, Mr. Peters also represents Luminant with the Nuclear Regulatory Commission (NRC), the Institute of Nuclear Power Operations (INPO), and the Nuclear Energy Institute (NEI).  He also serves as Vice Chair of the Board of Directors for the Utilities Service Alliance (USA).

Prior to joining Luminant, Mr. Peters held various managerial roles at other nuclear power stations, including Plant Manager and Vice President, Engineering and Projects. 

Mr. Peters is a graduate of the New Jersey Institute of Technology, and received a master’s degree from Virginia Tech. He has attended several executive programs, including the Wharton Executive Development Program and the Goizueta Directors Institute at Emory University.

April 2025

Vistra Energy /Luminant

6555 Sierra Dr. Irving, TX 75039


Dr. William Pate

William Pate

Representing Hospital Administrators. Appointed by Governor Abbott April 2019

Dr. William Pate is Program Director for Radiation & Occupational Safety for the University of Texas Medical Branch and serves as Radiation & Laser Safety Officer for the organization.  He has over 10 years of experience in health & safety and holds two master's degrees (public health & business administration) and a doctorate in public health with a focus on environmental & occupational health sciences.

Dr. Pate holds several board certifications including Certified Health Physicist (CHP), Certified Industrial Hygienist (CIH), Certified Safety Professional (CSP), Certified Hazardous Materials Manager (CHMM), Certified healthcare Safety Professional (CHSP), Certified Laser Safety Officer (CLSO), Certified in Public Health (CPH), and Certified Healthcare Facility Manager (CHFM).  He is also licensed as a medical physicist in Texas with a specialization in medical health physics.

Dr. Pate is secretary of the State of Texas Chapter of the Health Physics Society, and previously served as president. He is a professional member of the American Society for Healthcare Engineers, a member of the Health Physics Society and the NFPA Laser Fire Protection Technical Committee, and a plenary member of the American Academy of Health Physics. Additionally, he is vice chair of the UT System Radiation Safety Advisory Group and a member of the Laser Subcommittee of the American National Standards Institute.

April 2025

University of Texas Medical Branch

Department of Environmental Health & Safety

301 University Blvd
Galveston, TX 77555-111


Sanjay Narayan

Sanjay Narayan

Representing the Public. Appointed by Governor Abbott April 16, 2019.

Sanjay Narayan of Dallas is currently an attorney at Loewinsohn Flegle Deary Simon LLP. He is a member of the Texas State Bar, the New York State Bar, the Federalist Society, and the South Asian Lawyers Association. Additionally, he is a member of the Duke University Alumni Association, the University of Pennsylvania Law School Alumni Association, a Pro Bono contributor to the Dallas Volunteer Attorney Program, and active in the community.  His history of public interest and service includes interning for Sen. John Cornyn (R-TX) in Washington, D.C.  Sanjay received a Bachelor of Science in Economics and a Bachelor of Arts in Political Science from Duke University; a Juris Doctor from the University of Pennsylvania Law School; and a Certificate of Study in Business Economics and Public Policy from the Wharton School of Business.

April 2025

Loewinsohn Flegle Deary Simon LLP

12377 Merit Dr., Ste. 900

Dallas, TX 75251

John Hageman, MS, CHP


Representing Health Physicists. Reappointed in 2011.

Mr. Hageman is a Certified Health Physicist. He is Co-Chair of the Texas Nuclear Sector Working Group, which is tasked to develop a state-wide program for Preventive Radiological/Nuclear Detection to assure Texas can avoid an attack with a Dirty-Radioactive Bomb or an Improvised Nuclear Device. He is also Vice Chair of the Texas Private Sector Advisory Council and the Nuclear Reactor, Materials and Waste sector representative.

Mr. Hageman has served as the Southwest Research Institute (SwRI) Radiation Safety Officer (RSO) since 1996, As the SwRI RSO, he is responsible for the safe use of a large variety of radionuclides under a Texas broad scope Radioactive Material License issued for research and development. He is also responsible for the safe operation of a large variety of radiation producing machines used for laboratory analysis and for the SwRI High-Level Radiation Effects Facility.

Mr. Hageman has served as a consultant for the International Atomic Energy Agency (IAEA) in the design and for the operation of a portable hot cell used for the safe and secure dispositioning of irradiators and radioactive sealed sources. He has managed projects for radioactive source recovery, exchange, disposal, and security projects for the IAEA, Los Alamos and Sandia National Laboratories, and for several commercial clients.

Mr. Hageman, with the SwRI Geosciences and Engineering Div. managed several projects related to the NRC high-level radioactive waste (HLW) disposal. Prior to this he was the Health Physicist in SwRI’s Nuclear Nondestructive Testing and Services Div.

Before joining SwRI, he worked for Westinghouse Electric as a Nuclear Plant Trainer, where he supervised nuclear plant operations and the training of Naval officers in the Idaho Naval Reactors Facilities

Mr. Hageman is a Fellow in the Health Physics Society (HPS). He served as an HPS Board Member (03- 06), Treasurer, (09-12), Associate Journal Editor (03-present), and delegate to the International Radiation Protection Association Conferences (04 and 12). John is an Honorary Life Time Member of the South Texas Chapter of the HPS and has served as the Chapter’s newsletter Editor-in-Chief, since 1986, and President (88-91). He is the current Treasurer of the Bexar County Local Emergency Planning Committee.
April 2023

Southwest Research Institute

6220 Culebra Rd
San Antonio, TX


Gerald T. (Tim) Powell


Representing the Radioactive Waste Industry.  Appointed to the Texas Radiation Advisory Board in June 2016 by Governor Greg Abbott.

Mr. Powell is the President and Chief Executive Officer for STP Nuclear Operating Company. In this role, he is responsible for the strategic oversight of the overall safe and reliable operation and maintenance of all aspects of the South Texas Project Electric Generating Station including management of the regulatory interface with the Nuclear Regulatory Commission (NRC) and the Institute for Nuclear Power Operations (INPO) and management of radioactive waste. Mr. Powell represents STPEGS on the Nuclear Energy Institute, Board of Directors. He also serves on the Texas A&M Nuclear Engineering Advisory Council, the Electric Power Research Institute (EPRI) Nuclear Power Council Chairman, and is the chair of the Advisory Council for the Nuclear Power Institute (NPI). He also had the opportunity to serve on the Bay City Independent School District Board of Trustees for 14 years.

In his more than 30 years with the company, Mr. Powell has advanced through positions of increasing responsibility including Chief Nuclear Officer, Vice President, Technical Support and Oversight, Vice President of Engineering, Site Engineering Director, Systems Engineering Manager, Performance Improvement Manager, Radiation Protection Manager and Shift Supervisor Operations. During his time in Operations Mr. Powell was licensed as a Senior Reactor Operator by the Nuclear Regulatory Commission. He was also certified in Health Physics by the American Board of Health Physics in 1992.

Mr. Powell is a graduate of Texas A&M University with a Bachelor of Science degree in Nuclear Engineering and a Master of Business Administration. He is also a graduate of the Institute of Nuclear Power Operations’ Senior Nuclear Plant Manager course and the Senior Nuclear Executive Seminar.

April 2021

South Texas Project Nuclear Operating Co

P.O. Box 289 
Wadsworth, TX


Steve Harris


Representing Labor.  Appointed to the Texas Radiation Advisory Board in 2011. He serves as a member of the Industrial, Nuclear Power, Uranium and Waste Committee. 

Steve joined Dallas Fire Rescue in January 1978. In his almost 40-year career with the fire department he was both a paramedic and fire fighter. He continues to serve the department as a fire fighter and lieutenant for Dallas Fire Rescue’s Hazardous Materials Team.

During his career he has responded to the Oklahoma City Bombing in 1995, served as Hazmat Coordinator for Super Bowl XLV, was part of the security team for the George W. Bush Library Ceremony, in 2013, and spent a 2-week deployment in Louisiana for Hurricane Katrina, as a hazmat manager of the FEMA Texas Task Force Urban Search and Rescue team.

Mr. Harris is a member of: the International Fire Fighters Association, the North Texas Joint Terrorism Task Force, the Department of Homeland Security Center for Domestic Preparedness, and the Denton County Emergency Service District. Mr Harris has been appointed by the Governor to serve as a committee member for the STAR of Texas. He also serves as an instructor for: the Dallas Fire Rescue Training Academy, the Collin County College, the Department of Homeland Security Weapons of Mass Destruction, the Center for Radiological and Nuclear Training (CTOS) and the Department of Justice WMD/Explosives and Dissemination Devices.

April 2019 City of Dallas Fire Department

Hazmat/WMD Special Operations

1500 Marilla
Rm 7AS
Dallas, TX


Mark C. Harvey, Ph.D.


Representing Medical Professionals in Nuclear Physics.  Appointed to the Texas Radiation Advisory Board by Governor Greg Abbott in June 2016. 

Dr. Harvey is as Assistant Professor at Texas Southern University. He is a member of the Health Physics Society, American Association of Physicists in Medicine and the National Society of Black Physicists. Dr. Mark Harvey received a B.S. in physics from Virginia State University (Petersburg, VA). He completed his graduate studies in physics at Hampton University (Hampton, VA) where he earned his M.S. in physics and Ph.D. in experimental nuclear physics. Dr. Harvey’s doctoral research experiment in medium energy nuclear physics was carried out at the National Institute for Nuclear and High Energy Physics in Amsterdam, The Netherlands. After completing his doctoral work, Dr. Harvey went on to become a postdoctoral research assistant in the PHENIX collaboration at the Brookhaven National Laboratory (Upton, NY) where he collaborated on research in the field of relativistic heavy ion collision physics. After completing his postdoctoral tenure at Brookhaven, Dr. Harvey accepted a visiting assistant professorship at the Rochester Institute of Technology (Rochester, NY) where he taught introductory physics courses for one year, before returning to research as a postdoctoral fellow at the University of Texas M. D. Anderson Cancer Center (Houston, TX). Dr. Harvey has over 15 peer-reviewed publications and numerous presentations on his research at both national and international conferences. The National Institutes of Health (NIH) and the U.S. Nuclear Regulatory Commission (NRC) have awarded him federally funded grants. Dr. Harvey’s current research focuses on radiation dose assessment in medical health physics using Monte Carlo computer simulation techniques and also radiation detection apparatuses. He actively mentors students on various research projects in radiation physics, which include computational modeling and measurement of stray radiation in radiotherapy. Dr. Harvey currently serves as the director and primary instructor of the health physics program at Texas Southern University. He is also a technical reviewer for the NRC.
April 2021 Texas Southern University

Department of

3100 Cleburne St
Houston, TX


Kenneth V. Krieger


Representing Industry.  Trained in nuclear physics, science, or engineering. Reappointed in June 2016 and Health Physicist and Radiation Safety Officer.   

Mr. Krieger is the Radiation Safety Officer and Health Physicist for Radiation Technology Inc. in Georgetown, Texas. Radiation Technology is a small radiation safety consulting company specializing in the industrial environment. They preform license audits, licensing assistance, on site services, leak testing services, source transportation, and general health physics consulting. He is also the lead instructor in the company’s several radiation safety training courses. He is an expert in industrial gauging devices, their manufacturing and their dismantlement. He is a consultant with the International Atomic Energy Agency (IAEA) for the consolidation of sealed sources for borehole disposal.

He has more than 30 years of experience in radiation safety and more than 26 years of industrial safety, having had over 100 specific industrial safety training courses. He has served in many positions in the health physics professional organizations. He was the secretary for the American Academy of Health Physics, chairman of the Public Education Committee, now the Public Information Committee, on the program committee, and has been on the Part II panel for the American Board of Health Physics. He is now a current member for the Board of Directors for the National Health Physics Society, and has served in several position for the local chapter of the Health physics society. He is also certified in Health Physics by the American Board of Health Physics in 1999. He is also the Laser safety officer for the company.

Mr. Krieger has two Bachelor degrees and a Master’s Degree in Health Physics from Texas A&M University.

April 2021

Texas State Technical College

3801 Campus Dr
Waco, TX


Frank (Neal) Leavell, DDS


Representing Dentistry.  Appointed to the Texas Radiation Advisory Board by Governor Greg Abbott in 2016. 

Dr. Neal Leavell owns and operates Lampasas Dental Center. He has been practicing general dentistry in Lampasas since 1982. He received his bachelor’s degree from Baylor University and his dental degree from Baylor College of Dentistry. He completed a general practice residency at Audie Murphy VA Hospital in San Antonio.

Neal is a fellow of the Academy of General Dentistry. He has been active in the Texas Dental Association, having served as component president, delegate, and other offices. Neal is currently president of the Lampasas Economic Development Corp. board of directors. He has previously served on many other local boards and committees. 
April 2021

Lampasas Dental Center

1205 Central Texas Expy
Lampasas, TX

Darlene Metter, M.D., FACR


Representing Nuclear Medicine. Reappointed by Governor Abbott April 16, 2019.

Darlene Metter, MD, FACR is a Professor of Diagnostic Radiology and Family and Community Medicine in the Department of Radiology at UT Health San Antonio (UTHSA). She is board certified by the American Board of Radiology (ABR) and the American Board of Nuclear Medicine.

Dr. Metter’s current involvement in organized nuclear medicine includes membership on the Regulatory Commission’s Advisory Committee on the Medical Uses of Isotopes, ABR Nuclear Radiology certifying /MOC exam, and Joint Review Committee on Educational Programs in Nuclear Medicine Technology. Other current radiology leadership positions include the Texas Radiological Society, the American College of Radiology and the UTHSA Radioactive Drug and Research Committee. Dr. Metter has also received several teaching excellence awards, is a multi-invited local to international lecturer and has been invited for over thirty professorships.

April 2025

Univ. of TX
Health Science Center at San Antonio

Dept of Radiology

7703 Floyd Curl Dr
San Antonio, TX 78229


Simon Trubek, M.D.


Representing Radiology.  Appointed to the Texas Radiation Advisory Board in June 2016 by Governor Greg Abbott. 

Dr. Trubek is a partner at Austin Radiological Association where he is a Diagnostic Radiologist, Nuclear Radiologist, and Radiation Safety officer. Simon attended the University of Texas at Austin and Baylor Medical College in Houston. He did a surgical internship, Diagnostic Radiology Residency, and Nuclear Medicine Residency at Baylor College of Medicine.
April 2021 Austin Radiological Association

12554 Riata Vista Cir
Austin, TX


Kevin L. Raabe, REM

Representing the Uranium Mining Industry.  Appointed to the Board in 2000 by Governor Bush and twice reappointed by Governor Perry.

Kevin Raabe is Vice Chairman of the Board’s Industrial, Nuclear Power, Uranium and Waste Committee, and served previously as Chairman of the Committee.

Mr. Raabe currently works as Rio Grande Resources Corporation’s South Texas Operations Manager and Radiation Safety Officer for General Atomics Uranium Resources Corporation (GAUR). Mr. Raabe also serves on the Board of Directors for Rio Grande Resources Corporation (RGR) and Sequoyah Fuels Corporation (SFC).

Mr. Raabe continues in a 35-year career in the Uranium Mining Industry with General Atomics. He worked 18 years previously for Chevron Resources Corporation as a Reclamation Specialist, Environmental/Safety Manager, and Radiation Safety Officer. 

Mr. Raabe work experience includes licensing, permitting, mining, milling, safety, reclamation and decommissioning activities associated with the Panna Maria Uranium Mines and Mill, Jack Pump Uranium Mines, Rhode Ranch Uranium Mine and the Palangana In Situ Uranium Operations. He continues in an advisory role to GAUR’s Cotter Corporation in Colorado and Wyoming, RGR’s Mt. Taylor Mine in New Mexico, GAUR’s Beverly Uranium Production Operations in South Australia and SFC’s decommissioning of the Gore Oklahoma Uranium Conversion Plant.

Mr. Raabe is a 1980 graduate of Texas A&M University with a degree in Agricultural Engineering with graduate studies in Land Reclamation and is a Registered Environmental Manager (REM 7610) with the National Registry of Environmental Professionals. Mr. Raabe has co-authored several papers on reclamation and decommissioning of uranium mines and mills. He has served on DOE’s Local Task Force for the Falls City Uranium Mill Tailings Remedial Action Project, TAES Surface Mine Reclamation Workshop Planning Committees, the Ad-Hoc Committee on Radioactive Waste Disposal and as a guest lecturer for the Basic Radiological Health Course at the University of Texas Health Science Center.

Mr. Raabe currently serves as President of the Board of Directors for the Three Oaks Water Supply Corporation and on the Poth Independent School District Planning Committee. 
April 2017

General Atomics/Rio Grande Resources

Falls City, TX

Darshan J. Sachde


Representing the Public.  Appointed to the Texas Radiation Advisory Board in 2014. Reappointed April 2019 

Drr. Sachde is a Chemical Engineering consultant for Trimeric Corporation in Buda, Texas. He has lived in Austin, Texas since 2001, with degrees in Engineering and Public Policy from the University of Texas at Austin, culminating with a Ph.D. in Chemical Engineering. During his time at UT, Dr. Sachde worked on research projects that involved the technical and policy aspects of uranium extraction from seawater and carbon capture from power plants. He has also held positions with Samsung Austin Semiconductor and Austin Energy before his current role with Trimeric Corporation.

April 2025

Trimeric Corportaion

100 S. Main St. Buda, TX 78610


Mark Silberman, M.D.


Representing Pathology.  Appointed to the Texas Radiation Advisory Board in 2011. 

Dr. Silberman is Laboratory Director of Clinical Pathology Laboratories and a member of Clinical Pathology Associates, both based in Austin, Texas. He is board certified in Anatomic and Clinical Pathology with additional subspecialty certification in Hematology. Dr. Silberman completed his medical school, pathology residency, fellowship in Surgical Pathology and fellowship in Hematopathology at the Johns Hopkins University School of Medicine in Baltimore, MD. After training, he joined the faculty at Johns Hopkins as Instructor in the divisions of Hematopathology, Renal Pathology and Informatics. He joined the laboratory and pathology practice in Austin in 1999 to establish a department of Hematopathology. Dr. Silberman is a fellow of the College of American Pathologists and a member of the American Society of Clinical Pathologists, the American Medical Association and other professional organizations. 
April 2017

Clinical Pathology Associates

9200 Wall St
Austin, TX 78754


 Thierno Barry 


 Representing Insurance. Appointed by Governor Abbott April 16, 2019.

Thierno Barry received his Baccalaureate (High School diploma) from Lycée d’Arsonval – St. Maur, Creteil (Paris Region, France) and a Bachelor in Business Studies from the University of Houston in 1994. He started his insurance career in 1994 with AIG, where he held several positions with increased responsibilities and had executive oversight over personnel decisions, as well as business operations. In his current Role, with Chubb, Thierno is responsible for Production, distribution and relationship management with the insurance brokerage community, and other key trading partners. 
Thierno is a proud father (one daughter). She is currently attending college in the Houston area. In his spare time, Thierno enjoys traveling (Skiing, hiking), playing Racquetball and is an avid fan of Formula-One auto racing. Thierno is a native of The republic of Guinea, in West Africa, where he spent part of his youth, before moving to France, where he attended elementary & high school; he relocated to the USA, following his graduating from High school. Thierno is fluent in French.

April  2023

Chubb Holdings

919 Congress Ave., Ste. 1315
Austin, TX 78701


Lynn Slaney Silguero


Representing the Public. Appointed by Governor Abbott April 16, 2019.

Lynn Slaney Silguero of Frisco, Ebby Halliday Realtors, BROKER ASSOCIATE® & REALTOR®, CLHMS®, ABR®, SRES® Corporate Relocation Specialist, she is a member of the National Association of Realtors, Texas Association of Realtors, Metro-Tex Board of Realtors, and the Collin County Association of Realtors. Specializes in Residential, New Construction and Land development Real Estate. Additionally, she was appointed on the City of Frisco's 2018-2019 City Charter Review Commission, City of Frisco Social Services & Housing Board 2010-2016, and the City of Frisco Comprehensive Planning Advisory Committee 2013 -2016. Previous Multi Store Management  career in Corporate retail to joining Ebby Halliday Realtors in 2001.Graduate of Richardson ISD, Southwest Texas State University. Presently lives in Stonebriar Village in Frisco, TX since 2002.

April 2023

Ebby Halliday Real Estate

1415 Legacy Dr.
Frisco, TX 75034


Last updated July 6, 2020