THE PROBLEM OF REACTIVITY AND REACTION-RATE CALCULATIONS FOR MIXED GRAPHITE LATTICES

摘要

In a particular case, a mixed lattice fuelled with uranium at 0 and 3000 MWD/Te showed at 8 cm. pitch a small but appreciable change (~ 1％) in cell quantities, and at 25 cm. pitch a smaller change. It is found that the present method of calculating lattice reactivity, ignoring intercell effects, is probably adequate for standard-pitch metal-fuelled graphite-moderated systems. More general mixed-lattice systems, particularly if accurate values of cell qusntities are required, may need special calculation techniques; these are discussed, and techniques adequate for most systems are presented.