Since the development of nuclear weapons, federal agencies have been involved in securing U.S. nuclear assets against diversion, theft, and attack. Federal Efforts

The federal government has implemented a series of programs focused on detecting the illicit shipment of nuclear and radiological materials and protecting and securing nuclear weapons and material. These programs largely reside within the Departments of Defense, Energy, and State; agencies that became part of the Department of Homeland Security (DHS) upon its creation in 2002; and the Nuclear Regulatory Commission. Domestic Nuclear Detection Office

The Domestic Nuclear Detection Office (DNDO) was established by President Bush on April 15, 2005. Intended to centralize coordination of the federal response to an unconventional nuclear threat, DNDO is located within the Department of Homeland Security. The SAFE Port Act ( P.L. 109-347 ) gave the office statutory authority and specific responsibilities to protect the United States against radiological and nuclear attack. Among these responsibilities is to
develop, with the approval of the Secretary and in coordination with the Attorney General, the Secretary of State, the Secretary of Defense, and the Secretary of Energy, an enhanced global nuclear detection architecture with implementation under which (A) the Office will be responsible for the implementation of the domestic portion of the global architecture; (B) the Secretary of Defense will retain responsibility for implementation of Department of Defense requirements within and outside the United States; and (C) the Secretary of State, the Secretary of Defense, and the Secretary of Energy will maintain their respective responsibilities for policy guidance and implementation of the portion of the global architecture outside the United States, which will be implemented consistent with applicable law and relevant international arrangements. Because federal efforts to protect against nuclear attack are spread among multiple agencies, determining the full range of existing efforts, coordinating the outcomes of these efforts, identifying any overlaps and gaps between them, and developing an architecture integrating current and future efforts are likely to be evolving, ongoing tasks. The DNDO has organized these programs into a global nuclear detection architecture framework, a combined system of systems, which relies heavily on its technological component. According to the DNDO, the analysis methodology underpinning the global nuclear detection architecture continues to undergo revision and refinement:
In order to maximize the effectiveness of the FY 2008 edition of the [global nuclear detection architecture], DNDO will leverage the independent observation of a full peer review to ensure that the requirements called forth in the [global nuclear detection architecture] continue to reduce the risk from nuclear terrorism. Investment in the interior layer of the architecture has arisen mainly through existing programs designed to protect and safeguard national nuclear facilities and laboratories. Successes in developing and deploying these detector types may lead to significant advances in DNDO's ability to detect and prevent a radiological or nuclear attack. The success of DNDO's activities in establishing this architecture will likely require ongoing evaluation and oversight into the future. The DNDO is aware of the need to retain institutional knowledge. Additional coordination occurs between agencies participating in the global nuclear detection architecture as well.
The U.S. government has implemented a series of programs to protect the nation against terrorist nuclear attack. Some of these programs predate September 11, 2001, while others were established since then. Most programs are within the Nuclear Regulatory Commission; the Departments of Defense, Energy, and State; and agencies that became part of the Department of Homeland Security (DHS) upon its creation, and they are focused on detecting the illicit acquisition and shipment of nuclear and radiological materials and protecting and securing nuclear weapons. These disparate programs have historically been viewed as lacking coordination and centralized oversight.
In 2005, the Domestic Nuclear Detection Office (DNDO) was established within the Department of Homeland Security to centralize coordination of the federal response to an unconventional nuclear threat. The office was codified in 2006 through the passage of the SAFE Port Act (P.L. 109-347) and given specific statutory responsibilities to protect the United States against radiological and nuclear attack, including the responsibility to develop a "global nuclear detection architecture." Determining the range of existing federal efforts protecting against nuclear attack, coordinating the outcomes of these efforts, identifying overlaps and gaps between them, and integrating the results into a single architecture are likely to be evolving, ongoing tasks.
The global nuclear detection architecture is a multi-layered system of detection technologies, programs, and guidelines designed to enhance the nation's ability to detect and prevent a radiological or nuclear attack. Among its components are existing programs in nuclear detection operated by other federal agencies and new programs put into place by DNDO. The global nuclear detection architecture is developed by DNDO in coordination with other federal agencies implementing nuclear detection efforts and this coordination is essential to the success of the architecture.
This architecture is a complicated system of systems. Measuring the success of the architecture relative to its individual components and the effectiveness of additional investments are challenges. The DNDO is developing risk and cost methodologies to be applied to the architecture in order to understand and prioritize the various nuclear detection programs and activities in multiple federal agencies.
Congress, in its oversight capacity, has shown interest in the development and implementation of the global nuclear detection architecture and in the decision-making process attendant to investments in it. Other issues that may be foci of congressional attention include the balance between investment in near-term and long-term solutions for architecture gaps, the degree and efficacy of federal agency coordination, the mechanism for setting agency investment priorities in the architecture, and the efforts DNDO has undertaken to retain institutional knowledge regarding this sustained architecture effort.