Recirculation Suction Nozzle Plug 


The Preferred Recirculation Suction Nozzle Plug (N1) is a specialized plug specifically designed to match the ID of the reactor vessel. Made from polished Stainless Steel for easy decontamination, the N1 Plug features dual seals for redundant isolation. Hydraulic or mechanical reaction against the Shroud provides repeatable and reliable compression of the primary seal while ensuring the Plug maintains a seal during pipeline pressurization often seen with backfilling of lines or chemical decontamination.  

The auxiliary equipment includes a welded carbon steel Test and Training Mockup that is used for testing the Recirc Plug after maintenance in preparation for an outage. Also included is a Hoist Assembly that is often required for installation of the N1 Plug in a nozzle located directly below the guide rods and to maneuver the Plug around the in-vessel core spray piping.  


  • Equipped with a primary static and secondary inflatable seal designed to accommodate nozzle variations and vessel cladding surface irregularities.  

  • Can be qualified as a safety related isolation barrier. 

  • Equally suited for chemical decontamination isolation and routine valve maintenance.  

  • N1 Plugs can be installed from the refuel bridge in less than 2 hours.