Deterministic fixed order-level inventory models: An application for replenishment of radioactive source material for irradiation sterilizers

This paper investigates the timing of the replenishment of radioactive cobalt used in irradiation sterilizers. It is found that this model can be expressed as the continuous, deterministic case of a fixed order-level inventory model in which the demand rate is dependent on the level of inventory. The decision variable (the order point) can be determined using a univariable search technique. For certain values of the shape parameter of the demand function, the first derivative of the average profit function can be expressed as a polynomial from which the optimal order point can be determined. A numerical example is presented as well as an analysis of the sensitivity to changes in the solution and model parameters.