Stud Hole Plug Set 


The Preferred Engineering Stud Hole Plugs are used to seal RPV flange Stud Holes preventing cavity water from contaminating the threaded holes. Plugs are designed to ‘rest’ on the top thread and seal on counterbore walls.  


  • Body is machined from UHWM plastic which protects the counterbore and threads. 

  • Seal is EPDM rubber. 

  • Anodized aluminum IR tools pass through the RPV flange to allow installing with the RPV head in place. 

  • Test/training mockup is included.  

  • Storage Box to house the plugs and IR tools is optional.