Evaluation and Results cont'd

DOE-STD-3007-93

In all calculations, the actual storage buckets were ignored, thus allowing the assemblies

to be placed side by side. In reality, a spacing device exists that is connected to the monorail

hanger, which provides a small amount of spacing between the assemblies. For the purposes of

this evaluation, this spacing was ignored.

The last configurations to be evaluated were those in which the spacing between the fuel

assemblies was varied to determine reactivity effects. For this set of calculations the 3 x 3 x 1

water reflected array was modeled. The distance between the fuel assemblies was varied from 0

cm to 1.0 cm by 0.1 cm increments and from 1.0 cm to 4.0 cm by 1.0 cm increments. An example

of this configuration is shown in Figure 10, with X being the distance between fuel assemblies.

The results of these calculations are given in Table 1. As shown by these results, the increase in

spacing between fuel assemblies had an indistinguishable effect on reactivity. This result was

expected due to the large water volume fraction of a BORAX V Superheater fuel assembly and

already present moderator gaps inherent to the design.

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