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Code Manual for CONTAIN 2.0 - Federation of American Scientists

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several reasons, the assessment per<strong>for</strong>med by Williams and Griffith wi196] did not use exactly the<br />

same standard values in all cases. The values used in the latter work are given in Table 13-4. The<br />

standard scale factor, SSCALF, in this table was not specified in Levy. [Lev91] However, the intent<br />

was that the ratio <strong>of</strong> scaled hole sizes be used in the correlation and hence the standard scale factor<br />

is needed if the correlation is to function as intended.<br />

When the Levy correlation is invoked, it is recommended that the user employ the & values taken<br />

from the fits to the BNL or the SNL data that are given in Table 13-2, along with the corresponding<br />

standard values from Table 13-4. However, the user should remember that the mathematical <strong>for</strong>m<br />

<strong>of</strong> the Levy correlation is such that the standard values could actually be factored out and<br />

incorporated into the fitting constant; <strong>for</strong> any alteration in the standard values, one could find a<br />

revised value <strong>of</strong> & which would give equivalent results. As with any <strong>of</strong> the entrainment<br />

correlations, the essential requirement is to ensure that the & value used yields reasonable results,<br />

regardless <strong>of</strong> whatever values were specified <strong>for</strong> the other parameters.<br />

13.3.2.4.7 Whalley-Hewitt Standard Value. The Williams-Griffith modification <strong>of</strong> the Whalley-<br />

Hewitt correlation (Section 6.2.10. 1.1) was developed to correct what was considered to be some<br />

unrealistic dependencies upon liquid viscosity and surface tension. ~i196] When this version <strong>of</strong><br />

the Whalley-Hewitt correlation is used, a value is required <strong>for</strong> the surface tension <strong>of</strong> the standard<br />

liquid used in the experimental correlation assessments. This input is introduced by the keyword<br />

SURTES and the recommended value is 0.072 J/m*. This value corresponds to water, which was<br />

taken to be the standard liquid in the experimental assessments described in Reference Wi196.<br />

13.3.2.4.8 Weber Model. To use the Weber model, the user must also invoke the RPV discharge<br />

model and one <strong>of</strong> the available cavity entrainment models. The user must also specify five or more<br />

particle size bins. Failure to use at least five bins when the Weber model is used will result in an<br />

input error. The user may want to use ten bins to obtain higher resolution on the diameters <strong>of</strong><br />

airborne debris. Another important requirement is that the FDISTR mass distribution array may not<br />

be specified with the Weber model, since the model determines how mass is divided with respect<br />

to diameter. Each particle bin will automatically have an increasingly larger diameter when the<br />

Weber model is used, and the code assigns entrained mass into the bins based on the Weber criterion<br />

as described earlier. A side effect <strong>of</strong> this approach is that metals and oxides may not be initially<br />

separated into distinct bins when the Weber model is used. The composition <strong>of</strong> each bin will be<br />

individually tracked as always as the problem proceeds, such that smaller drops deplete their metal<br />

more quickly than larger drops. If one wants to per<strong>for</strong>m sensitivity calculations where metals and<br />

oxides are initially separate, then the Weber model can be deactivated. With the Weber model<br />

deactivated, the user can then speci~ the FDISTR matrix.<br />

The Weber model is highly dependent upon the average gas velocities through the cavity (or the exit<br />

velocity if the USEVOUT option is invoked). There<strong>for</strong>e, the user is cautioned to examine this<br />

velocity to ensure that it is reasonable. This velocity is provided in the output file if the PRFLOW<br />

global keyword is specified. Note that the plot file provides the gas velocity in the cavity exit flow<br />

path(s), which may be different than the entrainment velocity used in the Weber model. It is always<br />

important to check output <strong>for</strong> reasonableness. No specific guidance can be <strong>of</strong>fered at this time<br />

regarding the value <strong>of</strong> using the USEVOUT option.<br />

R O 13 57 6/30/97

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