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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.
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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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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WIPP’s SSCVS: A breath of fresh air
This spring, the Department of Energy’s Office of Environmental Management announced that it had achieved a major milestone by completing commissioning of the Safety Significant Confinement Ventilation System (SSCVS) facility—a new, state-of-the-art, large-scale ventilation system at the Waste Isolation Pilot Plant, the DOE’s geologic repository for defense-related transuranic (TRU) waste in New Mexico.
P. Wälti
Nuclear Science and Engineering | Volume 36 | Number 2 | May 1969 | Pages 133-142
Technical Paper | doi.org/10.13182/NSE69-A19713
Articles are hosted by Taylor and Francis Online.
The mathematical model of age-dependent branching processes is used to describe neutron slowing down and multiplication in an infinite medium. To construct the probability measure of the neutron branching process, it is necessary to determine the probability density for a neutron of age θ(=time elapsed since birth of the fission neutron) to have energy E. This problem, which is equivalent to the time-dependent slowing down problem, is solved for a scattering law of the form v(E)Σs(E → E′)dE′ = aEµh(E′/E) (dE′/E) and an absorption cross section satisfying the relation v(E) Σa(E) = bEµ + c. In this case, it is proved that there always exist particular “invariant” probability densities suffering only contraction during ageing, i.e., having the form . For the time-dependent slowing down problem with a Greuling-Goertzel kernel, the results are compared with those of Koppel. Particular attention is paid to stationary energy spectra.
