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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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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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Take steps on SNF and HLW disposal
Matt Bowen
With a new administration and Congress, it is time once again to ponder what will happen—if anything—on U.S. spent nuclear fuel and high-level waste management policy over the next few years. One element of the forthcoming discussion seems clear: The executive and legislative branches are eager to talk about recycling commercial SNF. Whatever the merits of doing so, it does not obviate the need for one or more facilities for disposal of remaining long-lived radionuclides. For that reason, making progress on U.S. disposal capabilities remains urgent, lest the associated radionuclide inventories simply be left for future generations to deal with.
In March, Rick Perry, who was secretary of energy during President Trump’s first administration, observed that during his tenure at the Department of Energy it became clear to him that any plan to move SNF “required some practical consent of the receiving state and local community.”1
R. Dierckx, A. Marchal, A. van Wauwe
Nuclear Technology | Volume 3 | Number 9 | September 1967 | Pages 532-539
Technical Paper and Note | doi.org/10.13182/NT67-A27934
Articles are hosted by Taylor and Francis Online.
The use of a direct reactivity meter for control-rod calibration was studied. The reactor model was simplified by reducing the number of delayed-neutron and photoneutron groups from 15 to 6, and by putting dn/dt equal to zero, without greatly affecting the accuracy of the reactivity measurements. The influence of errors in the knowledge of the parameters of the remaining six delayed-neutron groups was studied. Measurements were made on two reactors: ECO, a cold reactor; and ISPRA-I, a reactor with a strong long-lived photoneutron source. The measurements performed with the direct reactivity meter were compared to normal rod-drop measurement techniques and period measurement techniques, and were found to agree in general to ±2%. The long-lived source term, which depends on the reactor operation history, was found to a precision of better than ±1%.
