Patent Number: 
Section: claims

1. An apparatus for a nuclear reactor pressure vessel including a pressure vessel wall with a vessel penetration, the apparatus comprising:an electrical feedthrough including:a cylinder having an outside end and an inside end and a lumen passing between the outside end and the inside end,a flange connected to and sealed with the inside end of the cylinder but not sealing the lumen at the inside end of the cylinder,an electrical termination disposed in the cylinder and sealing the lumen of the cylinder,an outside electrical connector disposed at the outside end of the cylinder, andat least one electrical conductor passing through at least a portion of the lumen and having an end terminating at the electrical termination, the electrical feedthrough being mounted at the vessel penetration with the flange sealed against an inside surface if the pressure vessel wall, the cylinder passing through the vessel penetration of pressure vessel wall, and the outside electrical connector accessible from outside the pressure vessel,wherein the lumen of the cylinder is adapted to maintain structural integrity of the pressure vessel at normal operating pressure of the nuclear reactor, andwherein the outside end of the cylinder of the electrical feedthrough is disposed in the vessel penetration, radially inward of an outer surface of the vessel wall. 2. The apparatus of claim 1 wherein the electrical termination of the electrical feedthrough comprises:an end plate disposed at the outside end of the cylinder and at least one pressure fitting/connector sealed with and passing through the end plate, the end plate and the at least one pressure fitting/connector sealing the lumen of the cylinder at the outside end of the cylinder;wherein the pressure fitting/connector includes said electrical connector disposed at the outside end of the cylinder. 3. The apparatus of claim 2 wherein the pressure vessel is at an operating pressure and the lumen of the cylinder is at the operating pressure up to the outside end of the cylinder where the end plate and the at least one pressure fitting/connector seals against the operating pressure. 4. The apparatus of claim 3 wherein the operating pressure is at least 1000 psia. 5. The apparatus of claim 3 wherein the seal of the lumen at the outside end of the cylinder is provided by the end plate and the at least one pressure fitting/connector is rated for at least 2000 psia. 6. The apparatus of claim 1 wherein the at least one electrical conductor passing through at least a portion of the lumen is a mineral insulated cable (MI cable). 7. The apparatus of claim 1 wherein the at least one electrical conductor passing through at least a portion of the lumen is disposed inside a guide tube. 8. The apparatus of claim 1 further comprising:an annular weld sealing the flange of the electrical feedthrough against the inside surface of the pressure vessel wall. 9. The apparatus of claim 1 wherein the outside electrical connector is recessed into the vessel penetration. 10. The apparatus of claim 1 further comprising:a nuclear reactor core comprising fissile material disposed inside the pressure vessel, the pressure vessel further containing primary coolant water at an operating pressure, wherein the apparatus comprises a nuclear reactor. 11. The apparatus of claim 10 wherein the electrical feedthrough is electrically connected with an incore instrument disposed in the nuclear reactor core. 12. The apparatus of claim 1 wherein:the electrical termination of the electrical feedthrough comprises a hermetically sealed connector disposed at the inside end of the cylinder and sealing the lumen of the cylinder at the inside end of the cylinder; andthe at least one electrical conductor passes through the cylinder to electrically connect the hermetically sealed connector at the inside end of the cylinder and the outside electrical connector at the outside end of the cylinder. 13. The apparatus of claim 12 wherein the hermetically sealed connector comprises a sealed glass connector. 14. The apparatus of claim 12 wherein the hermetically sealed connector comprises a sealed ceramic connector. 15. The apparatus of claim 12 further comprising:a pressure vessel including said pressure vessel wall with said vessel penetration, the electrical feedthrough being mounted at the vessel penetration with the flange sealed against the inside surface of the pressure vessel wall, the cylinder passing through the vessel penetration of pressure vessel wall, and the outside electrical connector accessible from outside the pressure vessel. 16. The apparatus of claim 15 wherein the hermetically sealed connector comprises a sealed glass or ceramic connector. 17. The apparatus of claim 15 wherein the pressure vessel is at an operating pressure and the lumen of the cylinder is at atmospheric pressure up to the inside end of the cylinder where the hermetically sealed connector seals against the operating pressure. 18. The apparatus of claim 17 wherein the operating pressure is at least 1000 psia. 19. The apparatus of claim 17 wherein the seal of lumen at the outside end of the cylinder provided by the end plate and the at least one pressure fitting/connector is rated for at least 2000 psia. 20. The apparatus of claim 15 further comprising:an annular weld sealing the flange of the electrical feedthrough against the inside surface of the pressure vessel wall. 21. The apparatus of claim 15 wherein the outside electrical connector is recessed into the vessel penetration. 22. The apparatus of claim 15 wherein the electrical feedthrough is electrically connected with an internal control rod drive mechanism (CDDM) disposed inside the pressure vessel.