Code Manual for CONTAIN 2.0 - Federation of American Scientists

thermodynamic states. However, the energy associated with mass transport would not be formally
“conserved” across such an interface. While in this simple frost example, one could adjust the energy
accounting to account for the difference in enthalpy zeroes, in more realistic situations, it is not clear
how to make the adjustment. An example is a situation in which the same material sets are used but
somewhat different yet still acceptable approximations to the thermodynamic properties (within the
accuracy of the experimental data) are used on the two sides of the interface. In such a case, one
cannot properly evaluate the effect of the formal energy conservation error on the repository states,
because in general the precise degree to which the respective thermodynamic properties are correct
is not known (i.e., one does not know how to construct the best-estimate expression).
Another problem with the CONTAIN-CORCON interface is the fact that the CORCON lower cell
layers are switched discontinuously between the CONTAIN representation and CORCON
representation when CORCON becomes active and when it deactivates. This domain switching
produces discontinuities that are difilcult to interpret with respect to mass and energy conservation.
Therefore, to avoid such complications when CORCON is invoked, the CORCON intermediate and
concrete lower cell layers are considered to be external repositories even when CORCON is not
active.
A.3 Reposito rv Accounting
In this section, the internal repositories discussed in the preceding section are defined explicitly.
.. Also, expressions are given for the audit energies reported in mass and energy accounting output.
The internal repositories are defined in the following list. Each item in the list defines one
bookkeeping entity for the purposes of mass and energy accounting, even though some of the items
actually consist of a collection of repositories. For example, the first item defines the internal
repository referred to as the “atmosphere” repository in the present discussion.
1. Each cell atmosphere, including gases and condensable; aerosols that are composed of
materials with intemally-defmed or user-defined thermodynamic properties; and other such
materials that are not considered part of a debris field.
2. The suspended and trapped debris fields considered collectively in each cell but excluding
any trapped debris transferred to the lower cell.
3. Each heat transfer structure, including the surface condensate films and deposited aerosols
on both faces. The heat and mass transfer to and from a structure, including aerosol
deposition and concrete outgassing fluxes, are tracked for each structure. The aerosol
enthalpy for deposited aerosols is tracked for thermodynamic aerosol materials.
4. Each lower cell layer, with the exception of the CORCON layer and concrete layer when
CORCON is invoked. As discussed above, the latter layers are treated as external
repositories in the mass and energy accounting. To avoid having to define the basemat as
a repository, interactions with the lower cell basemat are treated as an external source to the
repository adj scent to the basemat. This treatment is compatible with direct basemat-tostructure
radiation, since this radiation is treated as occurring in two steps: basemat-to-
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