Abstract: History of the availability of the French nuclear fleet. The Kd, or availability coefficient, represents the available energy in relation to the maximum theoretical energy, corresponding to operation at the installed power all year round. Details: Availability of a power plant Fraction of the available power over the maximum theoretical power, taking into account only technical unavailability. The availability coefficient (Kd) is defined as the ratio between the actual annual production capacity (or annual deliverable) and the maximum theoretical production capacity (= installed capacity × 8,760 hours). The Kd, which only takes into account technical unavailability, i.e. scheduled outages, unplanned outages and test periods, characterises the industrial performance of a plant. Kd reflects the overall behaviour of the equipment. Load limitations due to causes external to the unit and due to internal causes not related to the equipment or the operation of the unit are not taken into account for the calculation of this rate. Here you will find a site that allows you to visualise, on a map, the state of availability of the present, past and future nuclear fleet.