Acting Assistant Secretary
Joel B. Bradburne
Joel Bradburne serves as the Acting Assistant Secretary for the Office of Environmental Management (EM). In this role he works to enable the safe and successful execution of the EM mission and provides leadership for the safe cleanup of the environmental legacy brought about from eight decades of nuclear weapons development and government-sponsored nuclear energy research.
Associate Principal Deputy Assistant Secretary for Field Operations, Office of Environmental Management
Gregory Sosson
Gregory Sosson is the Associate Principal Deputy Assistant Secretary for Field Operations for the Office of Environmental Management (EM). He is responsible for developing strategies, policy, and guidance for the 15 EM field sites in support of the EM mission. He oversees nuclear operations, safeguards and security, and technology development.
Associate Principal Deputy Assistant Secretary for the Office of Regulatory and Policy Affairs, Office of Environmental Management
Kristen Ellis
Kristen Ellis serves as the Associate Principal Deputy Assistant Secretary for the Office of Regulatory and Policy Affairs, and as the Director of Regulatory, Intergovernmental, and Stakeholder Engagement, within the US Department of Energy’s Environmental Management Office. Her portfolio includes infrastructure disposition, subsurface closure, regulatory compliance, waste and materials management and packaging and transportation.
Associate Principal Deputy Assistant Secretary for the Office of Corporate Services, Office of Environmental Management
Steve Trischman
Steve Trischman serves as the Associate Principal Deputy Assistant Secretary for the Office of Corporate Services, and as the Acting Deputy Assistant Secretary for Resource Management, within the US Department of Energy’s Environmental Management Office. His portfolio includes budget and planning, information systems, workforce management, acquisition and contract management and project management.
EM Field Managers
Leadership News
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Shawna Burtenshaw leads a team gearing up to finish the demolition of a submarine reactor prototype plant this year, a project that will reduce the legacy footprint of the Naval Reactors Facility and advance environmental cleanup at the Idaho National Laboratory Site. September 9, 2025September 9, 2025
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The National Cleanup Workshop is two weeks away, and there’s still time to register for it. September 9, 2025September 9, 2025
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A member of the EM leadership team recently attended the 9th International Forum on the Decommissioning of the Fukushima Daiichi Nuclear Power Station hosted by Japan’s Nuclear Damage Compensation & Decommissioning Facilitation Corporation. August 26, 2025August 26, 2025
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Joined by local, state and congressional leaders, Energy Secretary Chris Wright and other U.S. Department of Energy officials opened the doors to Savannah River National Laboratory’s new Advanced Manufacturing Collaborative. August 12, 2025August 12, 2025
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Advanced Manufacturing Collaborative in South Carolina Set to Lead on AI, Energy, and ManufacturingAugust 7, 2025
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Advances on the Oak Ridge Office of Environmental Management’s (OREM) cleanup mission are creating unique opportunities for the nuclear industry. July 29, 2025July 29, 2025