Code Manual for CONTAIN 2.0 - Federation of American Scientists

● activity coefficient models for the condensed phases (used in the aerosol generation and
radionuclide release calculation),
● an aerosol scrubbing model for subcooled pools, and
● a parametric treatment of core debris spreading across the concrete floor of the reactor cavity.
In addition to these model changes, CORCON Mod3 provides the user with the capability of
modifying a wide range of models and model panmeters. This additional flexibility allows the code
to be used in a broader range of applications.
5.8.3 System Components (2.2 From Bra93)
The principal components of the CORCON system are the core debris pool and the concrete cavity.
An overlying coolant pool, the atmosphere, and structure surroundings above the debris are treated
on the CONTAIN side of the CONTAIN-CORCON interface. Information about the concrete cavity
and core debris pool components is provided in Sections 5.2 and 5.3 respectively. The coolant pool
is discussed in Section 5.4. Because of differences between the CONTAIN implementation of
CORCON and the stand-alone code, these sections should be consulted for information on these
system components rather than Reference Bra93.
The composition of the debris pool and the concrete cavity is specified through user input in terms
of a “master list” of chemical species given in Table 2.1 of Reference Bra93. As in the stand-alone
code, not all of the species in the master list are available to the user for specification
of initial compositions. The aluminates (species 12 to 17) are a holdover from the viscosity
modeling of CORCON-Modl and are not used in CORCON-Mod3. The fission-product pseudo
species (oxides 24 to 28, metal 47, and gases 82 to 83) are used in the CORCON decay power model.
The initial fission product composition is determined within the code from the concentration of
fission products in the fiel. The fission product composition is then updated during the calculation
to account for addition of core material into the reactor cavity and release in the form of aerosols.
The VANESA model was developed using a somewhat simpler description of the melt, and
considers only the major condensed phase species. VANESA focusses primarily on gas phase
chemistry and it therefore includes a much more extensive species list for the gas phase. The
VANESA species list is shown in Table 2.2 of Reference Bra93.
5.8.4 Energy Generation (2.3. 1 from Bra93)
The CORESTAT decay power model included in CORCON as described in Bra93 is available in
the CONTAIN implementation of CORCON. Reference Bra93 notes that the ANSI-standard decay
power curve is not appropriate because of the potential for loss of important volatile radionuclides
from the core debris. This problem is addressed in the CONTAIN DECAY-HT implementation of
the ANSI-standard curve by allowing users to track specific radionuclides explicitly. The decay
power from the explicit radionuclides in the calculation is subtracted from the ANSI-standard decay
power value in the DECAY-HT model. This method is described in greater detail in Section 5.8.1.
The user has the option of using the DECAY-HT model within CORCON. If this is selected, the
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