Code Manual for CONTAIN 2.0 - Federation of American Scientists

~‘j
dU~
,,=
i “
[1
‘ji ~j‘d,j,rr
dt ji
‘j,n‘F,j
.
{[1
+ !5 ‘*k ~ ) - ‘in ‘rlink ‘kTin
hk(’Tsrc , ,, , ( , )}
k=l ‘ src
+ [%lch.rn - [%lconv - [%lrad
(6-17)
where U~j,~is the total internal energy of debris field n in cell i; h~(T) is the specific enthalpy of
debris material k at temperature T; T,,C is the temperature of the source debris; and Ti,, is the
temperature of debris in field n in cell i.
The fmt five terms of the energy conservation equation parallel the frost five terms of the debris mass
conservation equation. The fwst two terms on the right hand side represent the inflow and outflow
of energy resulting from intercell flow. The third term corresponds to the addition of energy from
debris sources, such as those to represent debris ejection from the RPV or entrainment in the cavity. ~
T~ will be the temperature of the non-airborne debris field if the source represents an entrainment
rate (i.e., specified as an ENTRAIN type source table or calculated by an entrainment model).
Otherwise, Tw will be the temperature specified in the source table. The energy associated with all
of the material species that are introduced into the debris field are added together, since one energy
conservation equation is used to represent all species in the field. A separate mass conservation
equation is used for each species of a field. The fouxt.hterm is the energy loss associated with debris
trapping, and the fifth term corresponds to the energy release from chemical reactions. The
contributions from each species are added together for the trapping term. Trapping is discussed in
detail in Section 6.3. The equations that govern the chemical energy term are provided in Section
6.4. Note that the chemical energy includes debris/gas chemical interactions. The energy resulting
from the recombination of hydrogen produced in DCH with local oxygen is not included in this term,
since this energy is added to the atmosphere.
The sixth term represents convective heat transfer between ahbome debris and the cell atmosphere.
The DCH convective heat transfer model is described in Section 6.5.1. The seventh and last term
represents radiative heat transfer from airborne debris to the cell atmosphere and surrounding
structures (including a coolant pool if one is present). The radiation model is described in Section
6.5.2. Convection and radiation are done on a field basis, not a species-specific basis; therefore,
there is no need to have a summation over species for these two terms. There is no term for decay
heat because the time scale for DCH is assumed to be sufficiently short that decay heating of
Rev O 614 6/30/97