A control rod drive mechanism (CRDM) for use in a nuclear reactor, the CRDM comprising: a hollow lead screw; a motor threadedly coupled with the hollow lead screw to linearly drive the lead screw in an insertion direction or an opposite withdrawal direction; a latch assembly having latches, the latch assembly secured with the hollow lead screw such that the latch assembly including the latches moves together with the hollow lead screw as the motor drives the hollow lead screw linearly in an insertion direction or an opposite withdrawal direction, the latch assembly configured to (i) latch to a connecting rod when the latches are closed so that the connecting rod and at least one control rod move together with the hollow lead screw when the hollow lead screw is driven by the motor and to (ii) unlatch from the connecting rod, the connecting rod being free to move in the insertion direction when unlatched; and a release mechanism characterised in that the release mechanism is configured to cause the latches of the latch assembly to open responsive to a scram condition to detach the connecting rod from the hollow lead screw such that the connecting rod and the at least one control rod scram but the hollow lead screw remains operatively coupled with the motor and does not scram, the release mechanism comprising: a lifting assembly; elongate members arranged parallel with the hollow lead screw and configured to be lifted by the lifting assembly; and a mechanical linkage configured to cause the elongate members to engage with and close the latches of the latch assembly when the elongate members are lifted by the lifting assembly. a hollow lead screw; a motor threadedly coupled with the hollow lead screw to linearly drive the lead screw in an insertion direction or an opposite withdrawal direction; a latch assembly having latches, the latch assembly secured with the hollow lead screw such that the latch assembly including the latches moves together with the hollow lead screw as the motor drives the hollow lead screw linearly in an insertion direction or an opposite withdrawal direction, the latch assembly configured to (i) latch to a connecting rod when the latches are closed so that the connecting rod and at least one control rod move together with the hollow lead screw when the hollow lead screw is driven by the motor and to (ii) unlatch from the connecting rod, the connecting rod being free to move in the insertion direction when unlatched; and a release mechanism characterised in that the release mechanism is configured to cause the latches of the latch assembly to open responsive to a scram condition to detach the connecting rod from the hollow lead screw such that the connecting rod and the at least one control rod scram but the hollow lead screw remains operatively coupled with the motor and does not scram, the release mechanism comprising: a lifting assembly; elongate members arranged parallel with the hollow lead screw and configured to be lifted by the lifting assembly; and a mechanical linkage configured to cause the elongate members to engage with and close the latches of the latch assembly when the elongate members are lifted by the lifting assembly. a lifting assembly; elongate members arranged parallel with the hollow lead screw and configured to be lifted by the lifting assembly; and a mechanical linkage configured to cause the elongate members to engage with and close the latches of the latch assembly when the elongate members are lifted by the lifting assembly.