The potential for use of fibre-optic devices, with emphasis on sensing applications, within the constraints of nuclear power-related environments is reviewed and discussed. The various process environments encountered within the nuclear power industry provide a wide range of opportunities for optical sensing technology and fibre-based devices offer potential advantages in a number of areas. The small volume and flexibility of fibres together with the multiplexing capability of fibre-optic systems are particularly attractive. The effects of operation in a radiation environment must be carefully addressed. They will be dependent on a combination of other environmental and operational parameters and the use of optical fibres in such circumstances is not automatically precluded. Enhanced lifetimes may be achieved via optical and thermal bleaching techniques.