Code Manual for CONTAIN 2.0 - Federation of American Scientists

discussed in Section 4.4.7; and (3) explicitly modeled submerged sources of gas, such as the SRV
discharge model discussed in Section 11.2 and the CORCON CCI model discussed in Chapter 5. ~
A contribution not taken into account in this velocity is that due to surface condensation or
evaporation of coolant at the pool surface, which is accounted for separately. The gas evolution
velocity is used in a number of places. One is to offset aerosol deposition processes, as discussed
in Section 7.2.3, at the pool-atmosphere interface. It is also used in the default option, as discussed
in Section 10.1.1.6, to calculate the degree of forced convection present with respect to the exposed
heat transfer structure surfaces. Jn the forced convection option, the contributions to the convective
velocity from each outflow and unsubmerged inflow gas flow path connected to the cell are taken
into account separately. The effect of all the submerged inflow gas paths, plus that of boiling and
explicit submerged sources, are taken into account in a single gas evolution velocity vP,~j(for cell
i). This velocity is processed as an “inflow” velocity according to the POOLFLOW parameters in
the VELCOEF input, or their defaults, to obtain the pool-gas interface contribution to the forced
convection velocity. (Prior to CONTAIN 1.2, only the effect of the dedicated suppression pool vent
discussed in Section 11.1.2 was taken into account, according to the SUPVENT parameters in that
input. The SUPVENT keyword is considered obsolete but if specified will be treated like the
POOLFLOW keyword.)
The gas evolution velocity v~~,in cell i is computed from the conditions calculated just above the
pool surface. The total flow enthalpy for all contributions is given by
WP~ihP~,i=qP&i+
,
q~Oili +qm
,,
~Oil i +qm
,,
~i +q~~v
,,
~i
(4-25)
where qw,iis defined in Equation (4-20) and ~flj and ~,hflj represents the implicit and explicit pool
boiling rates, respectively, discussed in Section 4.4.6. The other terms represent explicit submerged
sources of gas as discussed in Tables 4-3 and 44. The total mass flow rate in this equation is given
by the sum Wpgj = WPti+ w~flj + w~,mj + wLC,g,i + ‘SRV,g,is The temperature TPgjand density pP~,
of the flow are obtained by solving the enthalpy equation at a total pressure equal to the cell gas
pressure Pi, namely
WP~,ihP~,i=‘~ WP~,i,~h~(TP~,i)+WP~,v,i .h (T P.)
‘v(Tpg,i3ppg,v,i)+‘pg,!,l t pg,i’ 1
k
(4-26)
where N~~~is the number of ideal gases; WP~i~ is the flow rate of ideal gas k; h~ is the specific
enthalpy function of k; WP~,vJis the flow rate ‘of coolant vapo~ ~ is the coolant vapor specific
enthalpy; PP~,v,is the coolant vapor partial pressure; WP~,4,is the flow rate of homogeneously
dispersed liquid coolant and h! is the specific enthalpy of the coolant liquid.
The velocity of the flow is given by
Rev. O
‘pg,i = ‘pg,i/ ( ‘pg,i Ppg,i )
(4-27)
4-40 6/30/97