Uranium for Nuclear Power

Resources, Mining and Transformation to Fuel

Ian Hore-Lacy

• Publisher: Woodhead Publishing
• Year: 2016
• ISBN:
  9780081003336
• Topic: Technology & Engineering
• Subtopic: Mechanical Engineering
• Index: Technology & Engineering

Uranium for Nuclear Power: Resources, Mining and Transformation to Fuel discusses the nuclear industry and its dependence on a steady supply of competitively priced uranium as a key factor in its long-term sustainability. A better understanding of uranium ore geology and advances in exploration and mining methods will facilitate the discovery and exploitation of new uranium deposits. The practice of efficient, safe, environmentally-benign exploration, mining and milling technologies, and effective site decommissioning and remediation are also fundamental to the public image of nuclear power. This book provides a comprehensive review of developments in these areas.

• Provides researchers in academia and industry with an authoritative overview of the front end of the nuclear fuel cycle
• Presents a comprehensive and systematic coverage of geology, mining, and conversion to fuel, alternative fuel sources, and the environmental and social aspects
• Written by leading experts in the field of nuclear power, uranium mining, milling, and geological exploration who highlight the best practices needed to ensure environmental safety

Part I

Geology, Resources and Markets: Primary Uranium

Outline

1 Uranium for nuclear power

2 Geology of uranium deposits

3 Exploration for uranium

4 Uranium resources

5 The uranium market, supply adjustments from secondary sources, and enrichment underfeeding

1

Uranium for nuclear power

An introduction

Ian Hore-Lacy, World Nuclear Association, London, United Kingdom

Abstract

Compared with other mineral commodities, especially metals, whose utility has become evident by centuries of trial and error, the appreciation of uranium has developed from theories based in physics in the 1930s to exploit the unique energy density of uranium’s transformation in nuclear fission. Initially this was in the crucible of a world war, but always beyond military uses was the promise of the “uranium boiler” canvassed in a British report in July 1941—the work of “one of the most effective scientific committees that ever existed.”

Keywords

Nuclear fission; nuclear reactors; natural uranium; ²³⁵U; ²³⁹Pu; non-hydro renewables

1.1 Introduction and history

Compared with other mineral commodities, especially metals, whose utility has become evident by centuries of trial and error, the appreciation of uranium has developed from theories based in physics in the 1930s to exploit the unique energy density of uranium’s transformation in nuclear fission. Initially this was in the crucible of a world war, but always beyond military uses was the promise of the “uranium boiler” canvassed in the second British MAUD (Military Application of Uranium Detonation) report in July 1941—the work of “one of the most effective scientific committees that ever existed.”

Less than eight years after atomic bombs demonstrated the immense potential of uranium, the first precursor of today’s power reactors and numerous naval reactors had started up in Idaho, and a year later, electricity was generated in Russia. The focus was now on safe, controlled, long-lasting, and economical machines to harness nuclear fission for reliable electricity supplies. The focus has remained there, with over 500 civil nuclear reactors notching up more than 16,000 reactor-years of operation to 2015 with remarkably few accidents—and even those accidents had far less adverse effects than feared.

Today nuclear power has a unique position in relation to national energy policies as the only well-proven technology able to be deployed anywhere that can provide continuous reliable supply of electricity on a large scale and without nearly any CO₂ emissions or air pollution. It is widely agreed that energy generally, and electricity in particular, must increasingly be produced with much lower carbon dioxide emissions than hitherto. And as one-third of the world’s population aspires to enjoy the benefits of electricity that they have so far missed out on, the question of affordability looms larger than in the West, where it is by no means insignificant as a cost of living and an input to production, which must be competitive. Nuclear plants operate at low cost, and make electricity very affordable relative to any other low-carbon source.

Reliability is a key attribute of nuclear generation, and nuclear plants typically operate at near full capacity 24 h per day and year-round with only a pause for refueling every 18–24 months. This operation is irrespective of weather or season.

However, nuclear power is capital-intensive and this affects its ability to compete in liberalized electricity markets, particularly in competition with subsidized renewables and cheap gas, as elaborated next. Some long-term assurance of electricity sales at competitive prices with other sources apart from any subsidies on those is required (and without any subsidy beyond what is required to counter market distortions due to those sources).

But the clear message from practically every international authority and their reports is that nuclear power is essential for meeting the world’s growing need for affordable, clean, and reliable electricity. There is no credible reason to not greatly increase its role in world electricity production, and for industrial heat including desalination.

1.2 Energy density, other characteristics

The single most remarkable characteristic of uranium is its energy density: the amount of energy that a single kilogram can yield. Even so, exactly how much energy depends on the technology used to liberate it. One fuel pellet the size of a fingertip produces as much energy as one tonne of coal, even in the least efficient reactor.

“Natural uranium” is that which is found in nature—mostly in the Earth’s crust in a variety of geological environments. In most nuclear reactors, only about half of 1% of this is actually used, but even so it yields about 500 GJ/kg, about 20,000 times as much as black coal. In a fast neutron reactor, about 60 times this is achievable, and one day potentially more if technology and economics were pressed. But, in fact, uranium is fairly common and not a high-priced commodity—it has been less than $100/kg in recent years—so there is little incentive as of yet to push those boundaries from a resource perspective.

Like most other elements, uranium occurs as a mixture of isotopes, but with uranium, that fact is central to its use. Only one of the natural isotopes is directly usable, and that comprises only 0.7% of natural uranium. Hence, either power plants need to be designed accordingly, or the uranium needs to be enriched in that minor isotope, which is the subject of Chapters 11 and 12. In fact, the latter course of action accounts for 88% of the world’s nuclear power reactors (and all naval reactors).

Also, like most metals, uranium occurs in a variety of chemical forms, though most is as a mixed oxide of UO₂ and UO₃, characteristically U₃O₈. Chapter 2 offers a deeper discussion.

The concentration of uranium in its geological settings can range up to about 20% in some Canadian deposits, though 2%U is generally called a high-grade ore. Geological occurrences where it is defined as “ore” (economically recoverable) range down to about 0.01%U.

1.3 Resource situation

Uranium is approximately as common in the Earth’s crust as tin and zinc, and occurs in most rocks. Granites typically have up to 5 ppm U (which incidentally and at higher levels provides the heat for geothermal energy). Seawater contains a vast amount at 0.003 ppm U, which is recoverable, but not economical.

Our knowledge of what uranium (or anything else) is in the Earth’s crust arises from mineral exploration activities (see Chapter 3), which are expensive and mostly undertaken by mining companies that have negotiat...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Woodhead Publishing Series in Energy
• Part I: Geology, Resources and Markets: Primary Uranium
• Part II: Mining and Alternative Fuel Sources
• Part III: Conversion, Enrichment and Fuel Fabrication
• Part IV: Environmental and Social Issues
• Index