Nuclear reactor module with a cooling chamber for a drive motor of a control rod drive mechanism

In some embodiments, a nuclear reactor vessel comprises a containment vessel for a reactor pressure vessel (RPV); a control rod drive mechanism (CRDM) located in the containment vessel, the CRDM including drive motors configured to move control rods into and out of a nuclear reactor core located in the RPV; and a partition extending across a portion of the containment vessel configured to retain the drive motors in a separate fluid-tight barrier region within the containment vessel. Other embodiments may be disclosed and/or claimed.