INPRO is an international project to help ensure that nuclear energy is available to contribute in a sustainable manner to meeting the energy needs of the 21st century. A basic principle of INPRO in the area of environmental impact from depletion of resources is that a nuclear energy system will be capable of contributing to the energy needs in the 21st century while making efficient use of non-renewable resources needed for construction, operation and decommissioning. Recognizing that a national nuclear energy programme in a given country may be based both on indigenous resources and resources purchased from abroad, this publication provides background materials and summarizes the results of international global resource availability studies that could contribute to the corresponding national assessments.