Patent ID: 6301319
Filing Date: 2001-10-09
Classification: G21C,Y02E

Abstract:
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 thenwith 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; anddrawing 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.