Reactor vessel seal and method for temporarily sealing a reactor pressure vessel from the refueling canal

A reactor vessel seal for temporarily sealing a reactor pressure vessel from a water-filled refueling canal above the reactor pressure vessel, a removable closure head located on the reactor pressure vessel such that it seals against an upper flange of the reactor pressure vessel, and the reactor vessel seal being installed in place of the removable closure head for servicing the reactor vessel, the reactor vessel seal comprising:

• a seal cap having a surface connected to a flange which is complementary to the upper flange of the reactor pressure vessel;
• a seal located between the seal cap flange and the reactor pressure vessel flange;
• and
• a lifting rig connected to the seal cap for lifting the seal cap and placing it in position, with the seal cap flange in alignment with the reactor pressure vessel upper flange, such that the seal located between the seal cap flange and reactor vessel upper flange is compressed by hydrostatic pressure from water in the water-filled refueling canal acting on the surface of the seal cap as water in the reactor pressure vessel is evacuated.