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Division Spotlight
Nuclear Nonproliferation Policy
The mission of the Nuclear Nonproliferation Policy Division (NNPD) is to promote the peaceful use of nuclear technology while simultaneously preventing the diversion and misuse of nuclear material and technology through appropriate safeguards and security, and promotion of nuclear nonproliferation policies. To achieve this mission, the objectives of the NNPD are to: Promote policy that discourages the proliferation of nuclear technology and material to inappropriate entities. Provide information to ANS members, the technical community at large, opinion leaders, and decision makers to improve their understanding of nuclear nonproliferation issues. Become a recognized technical resource on nuclear nonproliferation, safeguards, and security issues. Serve as the integration and coordination body for nuclear nonproliferation activities for the ANS. Work cooperatively with other ANS divisions to achieve these objective nonproliferation policies.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Latest News
TerraPower begins U.K. regulatory approval process
Seattle-based TerraPower signaled its interest this week in building its Natrium small modular reactor in the United Kingdom, the company announced.
TerraPower sent a letter to the U.K.’s Department for Energy Security and Net Zero, formally establishing its intention to enter the U.K. generic design assessment (GDA) process. This is TerraPower’s first step in deployment of its Natrium technology—a 345-MW sodium fast reactor coupled with a molten salt energy storage unit—on the international stage.
Giovanni Maronati, Bojan Petrovic
Nuclear Technology | Volume 207 | Number 1 | January 2021 | Pages 1-18
Technical Paper | doi.org/10.1080/00295450.2020.1738829
Articles are hosted by Taylor and Francis Online.
Credibility requires predictability. Nuclear power plant (NPP) construction projects tend to be large and expensive, sometimes with high cost overruns far beyond those that might have been expected or predicted due to usual and recognized uncertainties and variations (e.g., in labor and materials costs combined with multiyear duration and complex construction logistics). This unaccounted for uncertainty brings the credibility of new NPP build projects into question and may prevent future projects from going forward. It is believed that the high initial capital cost of nuclear power is less of a hindering factor than the uncertainty about that cost. For nuclear power to regain credibility and enable future NPP construction projects, this unexpected uncertainty, or unknown unknown, needs to be assessed. Regular (expected) uncertainties (known unknowns) were addressed previously in a paper where the Iman-Conover method was used to account for correlated uncertainties. This paper addresses the impact of unexpected events (unknown unknowns), such as the Three Mile Island Unit 2 (TMI-2) accident. For this purpose, NPP construction in the United States is divided into two periods: pre-1979 (NPPs completed before the 1979 TMI-2 accident), and post-1979 (NPPs under construction when the accident happened and completed later). The latter group experienced significant schedule and budget overruns due to the change in regulation imposed after NPP construction was already under way. Analyzed a posteriori, this event and the escalated cost for the second group of NPPs was used to study the impact of a representative unexpected event.
An approach was developed to assess the range of potential risks, including those due to such unexpected events, and thus enable assigning appropriate contingencies. A traditional large four-loop pressurized water reactor [PWR12-Better Experience (BE)] was considered. With the inputs derived from the pre-1979 data, the expected total capital investment cost (TCIC) mean value for the PWR12-BE is found to be $3.3 billion, with a contingency of $1.3 billion, which corresponds to 39.4% of the TCIC mean. If the unknown unknowns are taken into account based on the post-1979 data, the TCIC mean value increases to $9.4 billion, with a cost contingency that is 108% of the TCIC mean derived for the pre-1979 NPPs.
Based on the experience-based assumed probability of unexpected events with large financial impact, it is then possible to derive an adequate contingency. The presented analysis offers a possible approach to treat unknown unknowns and to assess their impact on cost, providing the required contingency, as well as uncertainty in the construction time. In a broader context, this may provide quantitative tools to support making long-term energy policy decisions of new considered nuclear power projects.
