4. METHOD OF SOLUTION
Performs a complete steady-state, parallel channel thermal analysis of a rectangular water channel core with a plate-type fuel element. The digital code performs enthalpy and temperature rise calculations for the code average channel from input parameters. Two-phase core pressure drop calculations are performed using Bettis developed semi-empirical correlations. These calculations include the pressure drop effects of spatial acceleration, elevation, friction, and entrance and exit losses.
Hot channel pressure drop is computed by modifying the normal channel pressure drop by an input controlled plenum equation. To compute the hot channel flow where the flow vs pressure drop curve may contain inflections, a table of hot channel flow vs pressure drop is constructed by a stepwise reduction of flow from 100 percent of the average channel value to a flow producing steam quality in excess of 100 percent in the hot channel. The flow vs pressure drop tableis then searched and interpolated for a pressure drop value within two percent of the hot channel pressure drop as determined by the plenum effects on the normal channel. The flow corresponding to this pressure drop is considered the hot channel flow. Once the hot channel flow is determined, enthalpy, temperature and steam quality values are printed. Metal surface temperatures, mean centerline temperatures, and DNB (Departure from Nucleate Boiling) ratio calculations are made for each point from input properties and design equations.