Vladimir Knapp

Long Term Sustainability of Nuclear Fuel Resources

The basic issue in considering the contribution of nuclear power to solving the world’s energy problem in the future is the availability of uranium resources and its adequacy in meeting the future needs of nuclear capacity. Increased interest in nuclear energy is evident, and a new look into nuclear fuel resources is relevant. In this chapter we address the issue of nuclear fuel resources long term sustainability in relation to the expected growth of the world nuclear power. Three main aspects have to be analyzed in order to estimate how long the world’s nuclear fuel supplies will last: nuclear fuel resources (uranium and thorium), technologies for nuclear fuel utilization, and energy requirements growth scenarios including different scenarios for nuclear share growth. Uranium nuclear fuel resources are analyzed based on joint OECD Nuclear Energy Agency (NEA) and the International Atomic Energy Agency categorization which classifies resources into conventional resources and unconventional resources. Conventional resources are further divided into identified resources (reasonably assured and inferred) with four cost ranges and undiscovered resources (prognosticated and speculative) with three cost ranges. Analyzed unconventional resources include phosphate deposits and seawater. Total resources are estimated to about 6.3 million tons of uranium in identified resources and 10.4 million tons of uranium in undiscovered resources. The amount of uranium contained in phosphate deposits and seawater is estimated to 22 million tons and 4 billion tons, respectively. Thorium nuclear fuel resources are analyzed based on slightly different categorization than uranium one. Four categories are used: reasonably assured resources, estimated additional resources of type I and II, and prognosticated resources. Total thorium resources according to the latest OECD-NEA report are estimated to about 6 million tons. Detailed analysis of potential technologies for improved nuclear fuel utilization is required in order to assess long term sustainability of nuclear fuel resources. Nowadays, thermal converter reactor technology with once-through nuclear fuel cycle is used. The effectiveness of the technology can be improved in the area of enrichment process as well as by introducing reprocessing of the spent fuel on larger scale. Other technologies are also on the development stage that allows their implementation in short or medium period of time. These include: thermal and fast breeder reactors of different kind, thorium based fuel cycle, and conversion of uranium or thorium by particle accelerators or fusion devices. Very important aspect of long term sustainability of nuclear fuel resources are scenarios for energy requirements growth, and scenarios for growth of nuclear share in electricity production resulting in overall nuclear capacity growth. On one hand, low growth scenario has a moderate continuous growth strategy of 1.3% per year. On the other hand, high growth scenarios are required if nuclear energy is to give an essential contribution to carbon emission control. Finally, there is a scenario based on a compromise between low and high growth assumptions. These scenarios have been used to estimate exhaustion time periods of nuclear fuel resources for different fuel utilization technologies. The obtained exhaustion time periods range from 50 years for the once-through thermal converter fuel cycle with high increase in world nuclear capacity to many thousands of years for breeder reactor technology or for other methods of releasing the energy of U238. A development of these methods would require several decades, in return for practically unlimited amount of nuclear energy. Our analysis shows that nuclear fuel resources are not a limiting factor for a long term large scale nuclear power development. Our study is based on the most recent data on nuclear fuel resources, energy growth predictions, and technologies for the nuclear fuel utilization improvement, as well as our own developed code for calculation of nuclear fuel demand for different nuclear energy growth scenarios.

Long Term Fuel Sustainable Fission Energy Perspective Relevant for Combating Climate Change

A climate relevant and immediately available proven light water nuclear strategy with a potential to contribute essentially and timely to reduction of carbon dioxide emission to the year 2065 was assumed. The perspective of fission energy after that year is considered. Two technologies with long term perspective which need no or small amounts of uranium, i.e. fast breeders and molten salt thorium reactors were singled out. The main technical and safety characteristics were considered. In both of these technologies it is essential to have starter nuclides as neither U238 nor Th232 are fissile. It was investigated whether plutonium from spent fuel of light water reactors generated to the year 2065 would be present in quantities sufficient to continue operation on the same or similar level in both technologies. However, taking into account operational safety, proliferation risks, and waste production preference must be given to thorium technology.

Carbon Emission Impact for Energy Strategy in Which All Non-CCS Coal Power Plants Are Replaced by NPPs

A threat of global warming should convince the public to accept a nuclear fission energy contribution to climate change mitigation, at least for the climate critical years up to 2065. The nuclear fission energy is available now, with proven reactors, such as advanced LWR (light water reactors). Nuclear strategy in this paper outlines a proposal to replace all coal power plants (without carbon and capture storage system) with nuclear power plants in the period 2025-2065. Assuming once through advanced LWR technology, one would need nuclear capacity of 1,600 GW to replace coal power plants in that period. Corresponding reduction of emission would amount to 11.8 Gt of CO2. This energy strategy would reduce carbon emission by approximately 22% in the year 2065 and would be covered by projected uranium resources. An estimation of replacement costs showed that future carbon tax has a considerable potential to offset higher costs of nuclear replacement power.