RB Recirculation Sump Screen Replacement

In Sipro we established project documentation for replacement of Emergency Core Cooling Sump screen, which serves for filtering of pump suction water during emergency cooling of containment in NPP Krško. Companies placing the order were CCI AG Winterthur, Switzerland and Numip Ltd. Ljubljana, who was the performer of the installation.                                      


Picture 1: Supporting Structure


Picture 2: Screen Section and Maintenance Hole

Modification labeled with 531-AB-L has satisfied the requirements USNRC Generic Safety Issue GSI-191. The above mentioned requirements determine the installation of filter screen with a sufficiently large surface to minimize the loss of pumps NPSH but still high filtering quality. The screen is made up of perforated stainless steel sheet metal forming the total filtering area of 350 square meters. A hydraulic calculation has been made for the existing recirculation pumps in operation with the new screen. Mechanical integrity has been calculated, regarding to encumbrance by the hydraulic pressure drop and seismic forces, as it is demanded for the systems in NPP Krško. Installation of the filter screen in the Emergency Core Cooling Sump of the reactor building was performed during the outage 2007.                                                                                                 

                                                                                  Project Manager: Mladen Debeljak, B.Sc.M.E.