[en] Neutron transport and diffusion theory space- and energy-dependent reactor kinetics calculations were performed in the frequency domain to determine the sensitivity of an ex-core neutron detector to in-core vibrations and coolant boiling in a PWR. Results of these calculations indicate that the ex-core detectors are sensitive to neutron sources, to vibrations, and to boiling occurring over large regions of the core. Calculations were also performed on the effects of fuel burnup, boron concentration, and xenon poisoning on the spatial detector sensitivity. Results indicate that fuel assembly vibrations would produce approx. 60% greater ex-core detector response at the end of the first fuel cycle at Sequoyah-1. Results were compared with experimental ex-core neutron noise data obtained from Sequoyah-1 during the first fuel cycle. The predicted increase in ex-core neutron noise was experimentally observed in the 2.5- to 4.0-Hz frequency range (the range of frequencies associated with fuel assembly vibration), indicating that the vibrational amplitude of the fuel assemblies did not increase significantly during the first fuel cycle