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Office of Nuclear Threat Science

The Office of Nuclear Threat Science is responsible for overseeing the Nuclear Counterterrorism Program, an NNSA program that sustains specialized expertise and integrates and executes key activities to advise and enable technical aspects of U.S. Government nuclear counterterrorism and counterproliferation missions.

Nuclear Counterterrorism

The Nuclear Counterterrorism Program operates in partnership with weapons design-, stockpile science-, weapons surety-, and nuclear material-related programs. The Program focuses on nuclear threat devices, which include improvised nuclear devices, foreign weapon designs of proliferant concern, and any device that may have fallen outside of a foreign nuclear weapon state’s custody.


Leveraging already-existing NNSA nuclear weapons expertise, the Office of Nuclear Threat Science and its Nuclear Counterterrorism Program provide state-of-the-art training, operational support, technical advice, and expert policy recommendations in nuclear threat identification, weapons of mass destruction and improvised nuclear device defeat and render safe science and technology activities, and selected post-detonation nuclear forensics supporting attribution. The office recognizes that the ability to address the full spectrum of today’s nuclear threats requires the establishment of new partnerships with key countries, expansion of cooperative counterterrorism and nuclear threat response activities domestically and abroad, and the maintenance of continued technical leadership in understanding current and nascent nuclear threats.

Understanding Nuclear Threat Devices

To effectively reduce nuclear threats, it is imperative to first understand the threat itself. The Office of Nuclear Threat Science works to understand the full range of potential nuclear threat devices, from hypothetical improvised nuclear explosive devices to much more complex weapons developed by a nuclear weapon state that could be lost or stolen.

There are significant uncertainties associated with the nuclear threat device design spectrum because it is difficult to predict the exact nature of the threat (i.e. device composition and configuration)  outside of a specific case. These uncertainties directly impact our ability to assess nuclear terrorism risks and to design effective countermeasures. They also impact consequence management, forensics, and attribution efforts following a detonation. Therefore, understanding the threat affects the entire continuum of activities to counter or reduce the threat. This knowledge could mean the difference between success and failure in preventing a nuclear event.

Nuclear Threat Device Design SpectrumFigure 1. The ability to first understand the nuclear threat is essential to nuclear threat reduction.

Efforts to Reduce the Nuclear Threat

The Office of Nuclear Threat Science participates in the following activities to counter the nuclear threat.

  • Material Characterization: In support of efforts to secure materials of concern worldwide, the office works to identify, characterize, and understand the attractiveness of nuclear materials of interest.
  • Device Characterization: The office and its NCT Program support efforts to identify designs using nuclear and energetic and explosive materials. The types of possible designs range from crude improvised nuclear devices to proliferant devices, and post-identification, the office and its NCT Program ensure that designs of concern are shared across the U.S. nuclear community.
  • Response Support Activities: The office works to enhance detection and diagnostic capabilities, which provide science and technology capabilities for the global first responder and detection communities. The office also supports research and development initiatives for new and existing nuclear threat device render safe tools and modeling of device and design responses to these various tools. Finally, the office supports the forensics community in its attribution efforts through its use of pre-detonation knowledge and skill sets to inform post-detonation activities.
  • Policy Support: The office provides scientific and technical understanding, knowledge, and expertise in support of high-level policy initiatives.
  • International Engagement:The office supports U.S. relationships and information exchanges with partner nations on issues related to nuclear counterterrorism.