Experimental Measurements of Pressure Drop across Debris Beds on PWR Sump Screens in Support of Generic Safety Issue 191

摘要

The preparation of the debris material and the constituent loading sequence during debris bed formation can strongly influence the resulting pressure drop and physical integrity of a debris bed. PNNL generated debris beds consisting of only fiber material yielded relatively repeatable results. Complete debris beds were generated at debris loadings ≥ 217 g/m~2 in the 6-inch diameter test loop and ≥ 108 g/m~2 in the 4-inch diameter loop. Complete debris beds consisting of only particulate material were not formed at loadings up to 4350 g/m~2. In situ measurements of debris bed height and accompanying photographs show the debris beds contract and relax with continued cycling of the approach velocity. For most cases, the pressure drop decreased with increased temperature. However, the flow history to which the debris bed has been subjected impacts the measured pressure drop. Negligible differences in the measured pressure drop were obtained between debris beds generated on 5-mesh woven wire and 1/8-in. perforated plate.