Code Manual for CONTAIN 2.0 - Federation of American Scientists

cell-to-structure radiation model can be used with CORCON. However, as previously noted a
warning is issued if the net enclosure model is used, because it assumes a fixed area for the cavity
and this can lead to energy conservation problems. More detailed information about the radiation
models is provided in Section 10.3.
5.8.11 Concrete Decomposition and Ablation (2.3.8 from Bra93)
The description of this physical process in Section 2.3.8 of Reference Bra93 is directly applicable
to the CONTAIN implementation of CORCON. The model has been slightly altered to limit
ablation rates to 2 mmh to prevent numerical problems in some of the routines. This limit is several
times greater than the maximum ablation rates seen in CCI experiments performed to date.
5.8.12 Time-Dependent Melt Radius Option (2.3.9 from Bra93)
The description of this parametric model in Section 2.3.9 of Reference Bra93 is directly applicable
to the CONTAIN implementation of CORCON. As noted in Bra93, as implemented this model is
limited to flat-bottomed cylindrical cavities. Unlike the stand-alone implementation of CORCON
Mod3, up to 100 time points maybe specified. This increased number of points allows users to more
realistically use the results of a mechanistic spreading calculation to chive this parametric model.
5.8.13 Chemical Reactions (2.3.10 from Bra93)
The description of this physical process in Section 2.3.10 of Reference Bra93 is directly applicable
to the CONTAIN implementation of CORCON. Note that by default the new model for condensed
phase reactions of Zr with silicon dioxide is by default disabled. The user must speci~ the
CPCHEM keyword in the CORCON input block of the lower cell to enable this reaction. Another
change from the stand-alone implementation is that the option to disable coking is implemented
differently than as it is described in Bra93. It has been found that the approach described in Bra93,
where the chemical potential of condensed carbon is set to an artificially large value, leads to slower
convergence of the chemical equilibrium solver. Therefore, in the CONTAIN implementation
coking is disabled by skipping the relevant reactions rather than setting the chemical potentials of
condensed carbon to an artificially large value. This method was tested and shown to give equivalent
results as the method described in Bra93 but with much improved computational efficiency. Note
also that coking is disabled by default, whereas in previous implementations of CORCON in
CONTAIN coking was enabled by default. The user must specify the COKING keyword in the
CORCON input block to enable coking in the present implementation.
5.8.14 Mass and Energy Transfer (2.3.1 1 from Bra93)
The description in Section 2.3.11 of Reference Bra93 is directly applicable to the CONTAIN
implementation of CORCON.
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