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Conference Spotlight
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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RIC session focuses on interagency collaboration
Attendees at last week’s 2026 Regulatory Information Conference, hosted by the Nuclear Regulatory Commission, saw extensive discussion of new reactor technologies, uprates, fusion, multiunit deployments, supply chain, and much more.
With the industry in a state of rapid evolution, there was much to discuss. Connected to all these topics was one central theme: the ongoing changes at the NRC. With massively shortened timelines, the ADVANCE Act and Executive Order 14300, and new interagency collaboration and authorization pathways in mind, speakers spent much of the RIC exploring what the road ahead looks like for the NRC.
Weston M. Stacey, Jr.
Nuclear Science and Engineering | Volume 36 | Number 3 | June 1969 | Pages 389-401
Technical Paper | doi.org/10.13182/NSE69-A18736
Articles are hosted by Taylor and Francis Online.
A stochastic kinetic theory for space- and energy-dependent, zero power, nuclear reactor models is constructed from a last collision probability argument. The space and energy domains are partitioned into discrete cells. Equations are developed for the probabilities for transitions among the possible states of the reactor, and an equation is obtained for the probability generating function for these transition probabilities. Equations for the mean values, variances, covariances and correlation functions of the neutron and precursor distributions are derived. The stochastic distributions of neutrons and precursors are found to be space- and energy-dependent in subcritical reactors, but to attain a space- and energy- independent asymptotic form in supercritical reactors. The asymptotic distribution in a supercritical reactor is identical for the neutron and precursor distributions, and depends upon the manner in which the reactor is made supercritical. A method for applying the theory to low-source start-up calculations is suggested. The influence of spatial stochastic effects upon such calculations is demonstrated.