Abstract: A method including providing an internal control rod drive mechanism (CRDM) including an electric motor and a support surface including sealed electrical connectors electrically connected with the electric motor to deliver electrical power to the electrical motor, installing the internal CRDM inside a nuclear reactor, the installing including placing the support surface of the internal CRDM onto a support element inside the nuclear reactor, the placing causing sealed electrical connectors disposed on the support element to mate with the sealed electrical connectors on the support surface of the internal CRDM, wherein the nuclear reactor contains coolant water and the installing is performed with the internal CRDM submerged in the coolant water and the seals of the sealed electrical connectors of the internal CRDM and the support element are effective to prevent coolant water ingress into the sealed electrical connectors.

Abstract: An internal control rod drive mechanism (CRDM) including an electric motor is disposed in a nuclear reactor and further includes a support surface with sealed electrical connectors electrically connected with the electric motor power the motor. The internal CRDM is disposed on a support element secured inside the nuclear reactor. The support element includes sealed electrical connectors mating with the sealed electrical connectors on the support surface of the internal CRDM to power the electric motor. The sealed electrical connectors may be sealed glass, ceramic, or glass-ceramic connectors welded onto the ends of the MI cables extending from the motor. Springs, are disposed between the mating sealed electrical connectors of the support element and the support surface. A purge line is integrated with each mated connection.

Abstract: A nuclear reactor includes a nuclear reactor core comprising fissile material and a pressure vessel containing the nuclear reactor immersed in primary coolant water at an operating pressure. The pressure vessel has a vessel penetration passing through a wall of the pressure vessel. An electrical feedthrough seals the vessel penetration and has an outside electrical connector mounted at the pressure vessel. The outside electrical connector is at atmospheric pressure. The electrical feedthrough may include a flange disposed inside the pressure vessel and sealing against an inside surface of the wall of the pressure vessel. The outside electrical connector of the electrical feedthrough may be inset into the wall of the pressure vessel.

Abstract: Control rod drive mechanisms (CRDMs) include CRDM motors, and a support assembly provides bottom support of the CRDMs and includes a lateral alignment plate with openings receiving upper portions of the CRDMs. The upper portions of the CRDMs include compliance features engaging the openings of the lateral alignment plate. The compliance features may comprise angled leaf springs that wedge into the openings of the lateral alignment plate. In some embodiments the upper portion of each CRDM includes straps securing one or more cables to the upper portion of the CRDM, and the angled leaf springs are cut into or welded onto ends of the straps. Some embodiments further include a pressure vessel and a nuclear reactor core comprising fissile material disposed the pressure vessel, and the CRDM is an internal CRDM disposed in the pressure vessel along with the support assembly.

Abstract: A pressure vessel includes upper and lower vessel sections joined by a flanged connection. A nuclear reactor core includes an array of fuel assemblies comprising fissile material. The nuclear reactor core is disposed in the lower vessel section. A side-entry vessel penetration is located at a side of the pressure vessel and passes through one of (i) a flange of the flanged connection and (ii) the lower vessel section. An incore instrument routing tube extends from the side-entry vessel penetration and enters the reactor core from above the reactor core. The incore instrument routing tube extends from the side-entry vessel penetration with a declination angle AE and includes a 90°?AE downward turn to enter the reactor core from above. The declination angle AE may be zero so that the routing tube extends horizontally from the side-entry vessel penetration and includes a 90° downward turn.