Reprocessing and Recycling of Spent Nuclear Fuel

Robin Taylor

• Publisher: Woodhead Publishing
• Year: 2015
• Print ISBN: 9781782422129
• eBook ISBN: 9781782422174
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

Reprocessing and Recycling of Spent Nuclear Fuel presents an authoritative overview of spent fuel reprocessing, considering future prospects for advanced closed fuel cycles. Part One introduces the recycling and reprocessing of spent nuclear fuel, reviewing past and current technologies, the possible implications of Generation IV nuclear reactors, and associated safely and security issues. Parts Two and Three focus on aqueous-based reprocessing methods and pyrochemical methods, while final chapters consider the cross-cutting aspects of engineering and process chemistry and the potential for implementation of advanced closed fuel cycles in different parts of the world. - Expert introduction to the recycling and reprocessing of spent nuclear fuel - Detailed overview of past and current technologies, the possible implications of Generation IV nuclear reactors, and associated safely and security issues - A lucid exploration of aqueous-based reprocessing methods and pyrochemical methods

Part One

Introductory issues and future challenges

1

Introduction to the reprocessing and recycling of spent nuclear fuels

Kenneth L. Nash¹ [email protected]; Mikael Nilsson² [email protected] ¹ Washington State University, Pullman, WA, USA
² University of California Irvine, Irvine, CA, USA

Abstract

The consumption of energy correlates directly with the development of modern industrial societies and with the increase in average human life span that occurred during the twentieth century. During the second half of the century, fission-based nuclear energy became the dominant nonfossil carbon component of the global energy mix. Expanding the use and efficiency of fission energy should gain increasing significance as a means to reduce the impact of greenhouse gas emissions attendant to fossil carbon energy production. In this chapter, the history and future strategies for closing the nuclear fuel cycle to extend resources and reduce waste are discussed.

Keywords

PUREX

Actinide

Nuclear energy

Solvent extraction

Pyrometallurgy

Reprocessing

Global climate change

Fission products

Lanthanide

Radiolysis

Radiotoxicity

Radiochemistry education

Acronyms

AGR advanced gas-cooled reactor

AHA acetohydroxamic acid

CEA Commissariat à l'énergie atomique et aux énergies alternatives

COEX coextraction process

CRIEPI Central Research Institute of Electric Power Industry

HDBP dibutyl phosphoric acid

HLLW high-level liquid waste

HLW high-level waste

IFR integral fast reactor

IHM initial heavy metal

LET linear energy transfer

LMFBRs liquid metal fast breeder reactors

LWR light water reactor

MIBK methyl(isobutyl) ketone

MOX mixed oxide

OECD The Organisation for Economic Cooperation and Development

PUREX plutonium uranium reduction extraction

TBP tri-n-butyl phosphate

THORP thermal oxide reprocessing plant

UREX uranium extraction

VVER Voda Voda Energo Reactor

1.1 Introduction

1.1.1 Drivers for expansion of nuclear power/global climate/base load generation

The Industrial Revolution began in the early to mid-nineteenth century, with the introduction of mechanization of work. Mankind's new machines (e.g., sawmills, steam engines) led to a general increase in prosperity and the development of the concept of leisure time; mechanization of repetitive tasks allowed human society to move away from a model for society based on the physical labor of humans and their domesticated draft animals. The combustion of fuel to produce heat engines enabled an expansion of free time that led in general terms to an increase of interest in how and why the universe works as it does. This evolution produced a continuous wave of increasingly sophisticated new machines that grew naturally out of mankind's increasing knowledge and curiosity. By the end of the twentieth century, men had walked on the moon and split the atom.

It is estimated that in the early 1800s the population of the planet passed the one billion mark. At the middle of the nineteenth century, about 95% of the power needed to sustain the pace of industrialization was derived from renewable sources, primarily hydromechanical power and the combustion of wood (Ristinen and Krushaar, 1999). The exploitation of this apparently inexhaustible resource at the scale needed to sustain the pace of progress led ultimately to the significant depletion of native forestland in the United States and in Europe. By the middle of the nineteenth century, the consumption of fossil fuels began with the serious exploitation of the much higher energy density of coal. Though adventitious petroleum products have been in use since 4000 BCE, modern exploitation of petroleum at a large scale can reasonably be traced to Edwin Drake's construction of the first petroleum drilling machine in Titusville, PA, in 1859 (Dickey, 1959). The introduction of liquid fuels enabled more options in transportation and led to the development of the automobile and increased mobility by the end of the nineteenth century. The exploitation of oil also arguably represents the first deliberate extraction of natural gas. Until the development of the Bunsen burner and the concept of a natural gas pipeline, methane was utilized primarily for the production of light. At each stage of evolution in fossil fuel consumption, the energy density of the fuel decreased (relative to coal), but utility and ease of distribution increased.

Meanwhile, global population and consumption of energy in all forms continued to grow. By the beginning of the twentieth century, global population was nearing 2 billion and power production in the developed world was more than 70% based on coal combustion. As a result of increasing consumption of power by man's machines, the workplace became a less hazardous environment and average life spans began to increase. Aside from the influence of two World Wars and the Great Depression during the twentieth century, average life expectancy tracks almost linearly with energy consumption (Figure 1.1). Jumping ahead to the twenty-first century, planetwide population passed 7 billion in October 2011. Today total consumption of power remains somewhere between 80% and 85% derived from fossil carbon combustion; low-carbon nuclear power represents about 9% of global energy consumption.

Figure 1.1 Average life expectancy (at birth) correlation with per capita energy consumption 1850-2010 (U.S. Life Expectancy, 1850-2011; U.S. Energy Consumption, 1775-2009; U.S. Population, 1810-2010; U.S. Census Bureau, 2013).

The cumulative effects of fossil carbon consumption and increased overall human knowledge led by the end of the twentieth century to a rise in concerns about the potential climatological impact of more than 150 years of reinjecting fossil carbon into the accessible environment. The report of a steep rise in atmospheric CO₂ concentration since the beginning of the industrial revolution (representing a roughly 25% increase) combined with the perception of increased frequency of more severe weather events led ultimately to increasing concerns that global climate change was being fueled (pun intended) by fossil fuel consumption. This observation led to increased activity related to the means of either (1) replacing energy derived from fossil carbon with less CO₂-intensive alternatives or (2) devising effective strategies for sequestration of CO₂. In response to option 1, renewable resources (wind and solar, primarily) and nuclear power became favored topics for consideration. Government tax incentives have supported (in the United States and elsewhere) a significant increase in wind and solar contributions to the overall energy production balance. This renewable energy has captured an increasing share of global energy production. Unfortunately, the pace of industrialization in underdeveloped countries has resulted in a large increase in consumption of energy and effectively little displacement of fossil carbon combustion (though natural gas is displacing coal¹).

How large an impact on the livability of planet Earth the continued combustion of fossil carbon will have is in the province of climate modeling and mapping of the paleoclimate. In recent years, climatologists have almost universally agreed that continued injection of fossil carbon into the atmosphere will have deleterious effects, perhaps even in the near future. The development of alternative fuels that avoid the introduction of additional greenhouse gases into the atmosphere has spurred government subsidies supporting the creation of other power-production technologies that avoid fossil carbon combustion (in particular solar and wind technologies). Though climate models cannot offer ironclad proof of a negative impact of continued reinjection of fossil carbon into the atmosphere, the increasing consensus is that severe climate impacts may/will result from continuing the domination of power production by fossil carbon.

A companion question is whether renewable energy sources/conservation strategies can be improved adequately to serve the energy needs of the 9 (or more) billion inhabitants of the planet that are expected by mid-century. Government subsidies and tax credits have spurred development of new wind and solar installations, principally in the developed world. Conservation efforts also have been stepped up and they are having an impact on the rate of power consumption increase, but a growing global population base and increasing demand for energy-consuming devices (computers, phones, automobiles, etc.) will ensure that demand will continue to grow. It will be challenging to overcome the reality that the wind does not always blow, nor does solar radiation always penetrate to where the solar receptors are located. Developing strategies for efficient storage are critically important for these option...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Woodhead Publishing Series in Energy
• Preface
• Part One: Introductory issues and future challenges
• Part Two: Advances in aqueous separation processes
• Part Three: Pyrochemical processes
• Part Four: Implementation of advanced closed fuel cycles
• Index