[Note: Examples of each method are given in Section IV of this document.]
Contingency analysis, in general, is not required for incredible upset conditions.
Some systems will remain subcritical during any combination of credible upset conditions. For
such systems, simply state the fact in this section. (e.g., "As shown in Section 6.0, this system
will remain subcritical under any combination of credible upset conditions.")
6.0 EVALUATION & RESULTS
After the establishment of appropriate and sufficient subcritical limits (see Section 4.0), it must be
shown that both the normal and worst-case postulated upset conditions (may be limited to
credible conditions only) will be equal to or less than those values. If the actual conditions differ
from those used to establish the subcritical limits, it must be shown that the comparison is
If calculational techniques are used, a detailed description of the models should be presented in
this section. The level of detail should be sufficient to allow an independent reviewer to easily
reconstruct the computational model, compare the model with the descriptive information in
Section 2.0, and determine if the overall model is conservative. Sketches showing relevant model
dimensions should be included. (Very simple modeling that can clearly be described in a few
sentences is an exception.) Significant assumptions and simplifications should be stated. Mesh
spacing, quadrature order, the order of the Legendre scattering expansion, and other parameters
pertinent to numerical techniques should be specified or incorporated by reference.
All material compositions used in the evaluation should be specified in Appendix A. Typical input
listings should be given in Appendix B. Any of this information may be incorporated into the text
or by reference.
All calculational results should be reported in this section. Estimated uncertainties in the
methodology (e.g., statistical uncertainties associated with Monte Carlo calculations) and
sensitivities to modeling simplifications (e.g., effects of homogenization, dimension or geometry
modifications, etc.) should be stated.
DESIGN FEATURES (PASSIVE & ACTIVE) AND
ADMINISTRATIVELY CONTROLLED LIMITS &
Design features (passive and active) and administratively controlled limits and requirements for
the purpose of preventing or reducing the probability of a criticality accident should be stated in
this section or should be incorporated by reference.