Full Title: Criticality Calculations in Random Geometries
Author(s): Nuclear Energy Agency
Publisher(s): Nuclear Energy Agency
Publication Date: January 24, 2025
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Description (excerpt):
Several applications of interest in nuclear criticality safety involve random media, which are media where the geometrical and/or material properties can only be described by assigning some probability of finding a given nuclide concentration at a given position within the system under consideration. Prominent examples of applications involving random media include the modelling of the random fragmentation of fuel elements following in-pile fuel degradation after partial core melt-down during severe accidents, with melting, re-solidification and relocation, as occurred in the Three Mile Island and Fukushima Daiichi accidents.
In this context, the Nuclear Energy Agency Working Party on Nuclear Criticality Safety has decided to bring together specialists from several countries to investigate the impact of stochastic media on the calculation of key quantities in nuclear criticality safety, including effective multiplication factor, effective delayed neutron fraction and effective mean neutron generation time, for a simple, yet nontrivial benchmark configuration consisting of uranium oxide or mixed oxide fuel assemblies.