Patent Number: 052788768
Section: claims

1. A head for closing a nuclear reactor pressure vessel shell comprising: an arcuate dome having a convex outer surface and a concave inner surface, and including an integral annular head flange extending around a perimeter thereof, said head flange having an annular head mating surface for sealingly mating with said shell upon assembly therewith and a head internal passage extending through said head flange with a first port on said head mating surface; and  a vent line having a proximal end disposed in flow communication with said head internal passage, and a distal end disposed in flow communication with an inside of said dome for channeling a fluid therebetween, said vent line being fixedly joined to said dome and carried therewith when said head is assembled and disassembled from said shell.  said head flange further includes a top surface spaced above said head mounting surface, and said head internal passage includes a second port thereon;  said dome includes a nozzle extending therethrough from said outer surface to said inner surface; and  said vent line extends between said top surface and said nozzle, with said proximal end being disposed in flow communication with said second port at said top surface, and said distal end being disposed in flow communication with said dome nozzle.  an integral annular shell flange extending around a perimeter thereof, said shell flange having an annular shell mating surface sealingly mating with said head mating surface, a shell outer surface disposed perpendicularly to said shell mating surface, and a shell internal passage extending through said shell flange with a shell first port on said shell mating surface disposed in flow communication with said head first port, and a shell second port disposed on said shell outer surface.  said head flange further includes an inside surface facing radially inwardly above said head mating surface, and said head internal passage includes a second port thereon; and  said vent line extends from said flange inside surface along said dome inner surface, with said proximal end being disposed in flow communication with said head second port at said flange inside surface, and said distal end being open inside said dome in flow communication therewith.  an integral annular shell flange extending around a perimeter thereof, said shell flange having an annular shell mating surface sealingly mating with said head mating surface, a shell outer surface disposed perpendicularly to said shell mating surface, and a shell internal passage extending through said shell flange with a shell first port on said shell mating surface disposed in flow communication with said head first port, and a shell second port disposed on said shell outer surface. 2. A head according to claim 1 wherein said vent line is disposed externally of said dome and extends along said dome outer surface. 3. A head according to claim 2 wherein: 4. A head according to claim 3 in combination with said shell to define a pressure vessel, said shell further comprising: 5. A pressure vessel according to claim 4 further including an annular vent seal disposed between said head and shell mating surfaces around said respective first ports thereof for restricting leakage of said fluid from said vent line and between said head and shell flanges. 6. A pressure vessel according to claim 5 further including at least one annular head seal disposed between said head and shell mating surfaces and spaced radially outwardly from said vent seal. 7. A head according to claim 1 wherein said vent line is disposed internally of said dome and extends along said dome inner surface. 8. A head according to claim 7 wherein: 9. A head according to claim 8 in combination with said shell to define a pressure vessel, said shell further comprising: 10. A pressure vessel according to claim 9 further including an annular vent seal disposed between said head and shell mating surfaces around said respective first ports thereof for restricting leakage of said fluid from said vent line and between said head and shell flanges. 11. A pressure vessel according to claim 10 further including at least one annular head seal disposed between said head and shell mating surfaces and spaced radially outwardly from said vent seal.