The MSL plugs are installed to permit fuel movement while services are performed on the main steam lines. The reactor vessel nozzle plug system consists of aluminum and stainless steel plugs which can be inserted into the inlet and outlet nozzles. A functional specification is provided to the utility for approval to define design requirements of the RV nozzle plugs, docking tool and the installation nut torquing tool. This is prepared prior to design work to verify that the RV nozzle plugs meet the utility's requirements. Reactor vessel nozzle plugs are non-safety related with no safety analysis requirements.
Sufficient analysis including structural analysis is performed to verify safe operation.
Reactor vessel nozzle plugs are designed to resist a hydrostatic head of 35 feet. Reactor vessel nozzle plugs are qualified and tested per Westinghouse operating procedures. Reactor vessel nozzle plugs are installed using the manipulator bridge interfacing with docking tool. Plugs do not float but will include a safety lanyard for tie-off. No weight constraints beyond those required by the ISI tool.