South Africa operates two pressurized water reactors at the Koeberg Nuclear Power Station. Built in the seventies, the technology of the day lacked real time monitoring of the nuclear reactor core temperature. The core temperature is effectively extrapolated from empirical methods and procedures. Since the seventies, technology has grown in leaps and bounds and presently, the potential exists for real time monitoring of the reactor core temperature. This immediately enhances the safe, controlled and continued operations of the reactors into time. Additionally, in-core, real-time, on-line and multi-modal information gathering sensors throughout the nuclear power system could have the potential to improve efficiency and subsequently the overall cost of nuclear power systems. The research team has interest in applying fibre optic sensors with the fibres having a specific preparation or functional coating, which endows for sensitivity to various environmental parameters and accommodates working in extreme environments. There exists globally a growing interest in optical fibre based sensors for application in nuclear reactors because of their intrinsic attributes, such as package compactness, high bandwidth, multiplexing, ability to measure remotely in real time, and immunity to most electromagnetic perturbations. In-core-sensor, on-line technology for sensing temperature, as well as other parameters can enable instantaneous reactor state knowledge, thereby enabling novel reactor operations and management, even in emergencies. The paper describes the preparatory work of experimental research associated with exposing the specifically prepared fibres to the harsh environment within a nuclear reactor where the dose may be 2 GGy in two weeks of operation. The experimental methods includes inserting into the research reactor at Safari 1 of the Necsa, fibre optic samples configured as fibre bragg gratings (FBGs) and long period gratings (LPGs).