Experimental study of head loss through an LOCA-generated fibrous debris bed deposited on a sump strainer for Generic Safety Issue 191

• Head losses through fibrous beds were measured under various approach velocities.
• The thickness and the porosity of the bed were obtained.
• Permeability of the bed was calculated at different porosities.
• A modified Kozeny constant model was proposed.

Fibrous porous media have been studied in diverse engineering fields. In nuclear power plants, fibrous debris produced during the blow-down phase of Loss of Coolant Accidents (LOCA) is transported into the sump and becomes an important cause of head loss through the sump strainer affecting the Emergency Core Cooling System (ECCS) performance. In this study, a vertically installed strainer plate in a horizontal pipe flow loop was designed to generate fibrous beds on the strainer and permit measurement of the head loss through the beds. NUKON fibrous insulation material was used as the fibrous debris prepared by shredder method explained in NUREG/CR-6224 report. The head loss data with the shredder method was mainly analyzed considering porosity and fibrous bed thickness. A modified head loss model was suggested and compared to the head loss models developed in previous studies.