Patent Number: 
Section: claims

1. A nuclear reactor control rod drive assembly, comprising:a control rod drive mechanism coupled to a drive shaft and operable to urge the drive shaft through a portion of an inner volume of a reactor vessel in a first direction toward a reactor core and in a second direction away from the reactor core;a control rod manifold coupled to the drive shaft;a plurality of control rods coupled to the control rod manifold, the plurality of control rods adjustable among a plurality of positions within the inner volume of the reactor vessel based on operation of the control rod drive mechanism; andat least one joint positioned between the control rod drive mechanism and the plurality of control rods, the at least one joint having a first failure strength in the first direction and a second failure strength in the second direction, the first failure strength being greater than the second failure strength,wherein the joint comprises a plurality of joints, the plurality of joints connecting the control rod manifold and the plurality of control rods, wherein the plurality of joints provide the first failure strength and the second failure strength between the manifold and the plurality of control rods,wherein the manifold further comprises a plurality of pockets, the plurality of control rods being positioned in the plurality of pockets, andwherein each of the plurality of pockets is formed with an inward-directed flange. 2. The nuclear reactor control rod drive assembly of claim 1, wherein the control rod drive mechanism is positioned external to the reactor vessel. 3. The nuclear reactor control rod drive assembly of claim 1, wherein a portion of the drive shaft comprises the joint. 4. The nuclear reactor control rod drive assembly of claim 3, wherein the portion of the drive shaft is located at a distal end of the drive shall, that is near the control rod manifold and is opposite a proximal end of the drive shaft that is coupled to the control rod drive mechanism. 5. The nuclear reactor control rod drive assembly of claim 4, wherein the joint comprises an annular member housed within a reduced diameter portion of the drive shaft. 6. The nuclear reactor control rod drive assembly of claim 4, further comprising an aperture formed in the manifold adjacent the distal end of the drive shaft, the aperture defining a fluid pathway for fluid to apply pressure through the manifold and to the distal end of the drive shaft when the drive shaft is connected to the manifold. 7. A nuclear reactor control rod drive assembly, comprising:a control rod drive mechanism;a drive shaft coupled to the drive mechanism, the drive mechanism operable to move the drive shaft in a first direction toward a reactor core and in a second direction away from the reactor core; anda manifold coupled to the drive shaft with a first connection, the manifold comprising a second connection to couple a control rod to the manifold,wherein at least one of the first connection or the second connection further comprises a first failure strength in the first direction and a second failure strength in the second direction, the first failure strength being greater than the second failure strength,wherein the second connection comprises a cutaway section formed in the control rod, andwherein the cutaway section is received within a pocket formed in the manifold. 8. The nuclear reactor control rod drive assembly of claim 7, wherein the pocket further comprises an additional cutaway section, a shear member being trapped between the cutaway section and the additional cutaway section. 9. The nuclear reactor control rod drive assembly of claim 7, the pocket further terminating in an inward-directed flange.