Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate the magnetic fields across a full stroke length of the control element in the reactor. A closed coolant loop may cool the induction coils, which may be in a vacuum outside the isolation barrier. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Methods of operation include selectively energizing or de-energizing induction coils to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate the magnetic fields across a full stroke length of the control element in the reactor. A closed coolant loop may cool the induction coils, which may be in a vacuum outside the isolation barrier. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Methods of operation include selectively energizing or de-energizing induction coils to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Arrangements and devices for reducing and/or preventing wear of a thermal sleeve in a nuclear reactor are disclosed. Arrangements include a first structure provided on or in one the thermal sleeve and a second structure provided on or in the head penetration adapter. At least a portion of the first structure and at least another portion of the second structure interact to resist, reduce, and/or prevent rotation of the thermal sleeve about its central axis relative to the head penetration adapter. Devices include a base for coupling to a guide tube of the reactor and a plurality of protruding members extending upward from the base. Each member having a portion for engaging a corresponding portion of a guide funnel of the thermal sleeve.

A method of replacing a damaged thermal sleeve in a reactor vessel head adapter that connects a control rod drive mechanism to a reactor vessel head includes the steps of accessing the damaged thermal sleeve, removing the damaged thermal sleeve, and obtaining a replacement thermal sleeve having an elongated tubular body, a flanged region, and a plurality of slots defined in the elongated tubular body, each slot having a width which is sufficient to narrow a maximum outside diameter of the flanged region from a first diameter to a second diameter. The method further includes altering the maximum outside diameter of the flanged region on the replacement thermal sleeve, inserting the replacement thermal sleeve into an opening of a tubular member from an underside of the reactor vessel head, and expanding the maximum outside diameter of the flanged region into a recess of the reactor vessel head adapter.

A power distribution plate (PDP) sits on top of a support plate. Control rod drive mechanism (CRDM) units are mounted on top of the PDP, but the PDP is incapable of supporting the weight of the CRDM units and instead transfers the load to a support plate. The PDP has receptacles which receive cable modules each including mineral insulated (MI) cables, the MI cables being connected with the CRDM units. The PDP may further include a set of hydraulic lines underlying the cable modules and connected with the CRDM units. The cable modules in their receptacles define conduits or raceways for their MI cables and for any underlying hydraulic lines.

A power distribution plate (PDP) sits on top of a support plate. Control rod drive mechanism (CRDM) units are mounted on top of the PDP, but the PDP is incapable of supporting the weight of the CRDM units and instead transfers the load to a support plate. The PDP has receptacles which receive cable modules each including mineral insulated (MI) cables, the MI cables being connected with the CRDM units. The PDP may further include a set of hydraulic lines underlying the cable modules and connected with the CRDM units. The cable modules in their receptacles define conduits or raceways for their MI cables and for any underlying hydraulic lines.

Arrangements and devices for reducing and/or preventing wear of a thermal sleeve in a nuclear reactor are disclosed. Arrangements include a first structure provided on or in one the thermal sleeve and a second structure provided on or in the head penetration adapter. At least a portion of the first structure and at least another portion of the second structure interact to resist, reduce, and/or prevent rotation of the thermal sleeve about its central axis relative to the head penetration adapter. Devices include a base for coupling to a guide tube of the reactor and a plurality of protruding members extending upward from the base. Each member having a portion for engaging a corresponding portion of a guide funnel of the thermal sleeve.

A replacement thermal sleeve with a flange for a reactor vessel closure head penetration adapter housing. By altering a diameter of the flange, a replacement thermal sleeve can be installed through the narrow diameter of the penetration adapter housing opening from under the reactor vessel head. The flange can be compressible or expandable or the tubular wall of the thermal sleeve can be inserted in longitudinal sections, one at a time, into an opening in the underside of the penetration head adapter and reformed within the opening when fully inserted.

This disclosure relates to reactor control, and more particularly to a control rod drive mechanism and a reactor control system. The control rod drive mechanism includes a lifting-lowering assembly, a mounting assembly and a release assembly. The mounting assembly is configured to mount a control rod. The lifting-lowering assembly includes a fixing component, a scissor-type lifting-lowering mechanism and a lifting-lowering component. An end of the scissor-type lifting-lowering mechanism is connected to the fixing component, and the other end is connected to the lifting-lowering component. The scissor-type lifting-lowering mechanism is configured to drive the lifting-lowering component to move close to or away from the fixing component. The release assembly is movably arranged on the lifting-lowering component, and is detachably connected to the mounting assembly. The release assembly is configured to move relative to the lifting-lowering component when power is off to release the mounting assembly.

This disclosure relates to reactor control, and more particularly to a control rod drive mechanism and a reactor control system. The control rod drive mechanism includes a lifting-lowering assembly, a mounting assembly and a release assembly. The mounting assembly is configured to mount a control rod. The lifting-lowering assembly includes a fixing component, a scissor-type lifting-lowering mechanism and a lifting-lowering component. An end of the scissor-type lifting-lowering mechanism is connected to the fixing component, and the other end is connected to the lifting-lowering component. The scissor-type lifting-lowering mechanism is configured to drive the lifting-lowering component to move close to or away from the fixing component. The release assembly is movably arranged on the lifting-lowering component, and is detachably connected to the mounting assembly. The release assembly is configured to move relative to the lifting-lowering component when power is off to release the mounting assembly.