Patent Number: 063013193
Section: claims

1. The method of sealing a reactor pressure vessel (RPV) submerged in a pool of water, comprising the steps of: removing a RPV head from a RPV flange, thereby opening the RPV to the pool of water;  providing a temporary RPV head having an elliptically shaped dome and a circumferential flange, the dome having a thickness of about one inch or less and having lift rig connections, the circumferential flange having radially spaced apart grooves retaining seal rings;  attaching a RPV lifting rig to the lift rig connections of the dome of the temporary RPV head;  positioning the temporary RPV head flange on the RPV flange under the weight of the dome and attached RPV lifting rig; and then  with the lifting rig attached to the lifting rig connections of the dome of the temporary RPV head, pressure testing the space between the spaced apart seal rings; and  drawing water out of the RPV down to a water level below the temporary RPV head flange before hydrostatically pressure testing the space between the spaced apart seal rings. 2. The method of claim 1, wherein the space between the seal rings is pressurized to a pressure of about 20 pounds/square inch. 3. The method of claim 2, wherein the space between the seal rings is pressurized for about 5 minutes.