Chemistry of Nuclear Fuel Waste Disposal (The)

ISBN9782553010255 EditorPresses internationales Polytechnique pages182 Published2002-07-04
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One of today's most serious concerns is the disposal of nuclear fuel waste; no other peacetime technology evokes such public disquiet. In this book, Dr. Wiles expertly describes the nature of radioactivity and nuclear power. The subject matter is presented in a clear and eloquent manner and the author discusses, in detail, the management of radioactive waste using the multi-barrier system as well as taking a rather unusual approach to risk assessment. Based on a precise knowledge of the chemical properties of radionuclides in spent fuel, The Chemistry of Nuclear Fuel Waste Disposal follows each principal radionuclide as it travels through numerous levels of obstruction. Findings show that only two radionuclides effectively reach the biosphere, and do so only after many thousands of years.

This book is a must for anyone interested in nuclear waste disposal including the processes involved, the areas of uncertainty and the bases for statements about risk to human and other life. Policymakers and their advisors will find it an invaluable source of information on the state of knowledge and the scientific background for the recommendations on which policy decisions and investments will be made


Anyone seriously interested in nuclear waste disposal will find information and easily under-standable explanations of the processes involved, the areas of certainty and of uncertainty, and the bases for statements about risk and safety to human and other life over time.

Policy-makers and their advisors will find this book a reliable source of information on the state of knowledge, the necessary assumptions, and the scientific background for the recommendations on which policy decisions and investments will be made.

About one-fifth of the world's supply of energy is derived from nuclear fission. While this important source of power avoids the environmental and re-source problems of most other fuels, and although nuclear accident statistics are much less alarming, no other peacetime technology has evoked such public disquiet and impassioned feeling.

Central to these fears is the management and disposal of radioactive waste. An expert Canadian panel in 1977 recommended permanent disposal of wastes in deep geological formations, providing a basis for subsequent policies and research. In 1988, the Federal Environmental Assessment Review Office (FEARO) appointed a panel to assess pro-posed disposal concepts and to recommend govern-ment policy. The panel in turn appointed a Scientific Review Group to examine the underlying science. Behind these issues lay the question: How well is the chemistry understood? This became the principal concern of Professor Donald Wiles, the senior nuclear chemist of the Scientific Review Group.

In this book, Dr. Wiles carefully describes the nature of radioactivity and of nuclear power and discusses in detail the management of radioactive waste by the multi-barrier system, but also takes an unusual approach to assessing the risks. Using knowledge of the chemical properties of the various radionuclides in spent fuel, this book follows each of the important radionuclides as it travels through the many barriers placed in its path. It turns out that only two radionuclides are able to reach the biosphere, and they arrive at the earth's surface only after many thousands of years.

A careful analysis of the critical points of the disposal plan emphasizes site rejection criteria and other stages at which particular care must be taken, demonstrating how dangers can be anticipated and putting to rest the fear of nuclear fuel waste and its geological burial.
Donald R. Wiles studied nuclear fission chemistry at McMaster University in Ontario, at the Mass-achusetts Institute of Technology and at the University of Oslo, Norway. After following other branches of radiochemistry at Carleton University, at Institutul de Fisica Atomica in Bucharest, at Brookhaven National Laboratory and at the Kernforschungszentrum Karlsruhe in Germany, he joined the Scientific Research Group whose deliberations gave rise to this book.

Dr. Wiles is unique as a radiochemist having been employed by neither the uranium industry nor any branch of the Government, and thus is able to present a quite fresh view of the problem and its chemistry. He has retired from full-time duties at Carleton University in Ottawa but is still active as a teacher, writer and lecturer.
1- Introduction
Electric Power in the World. History of Nuclear Power. Nuclear Power Reactors in the World. What is the Problem?. Current Storage of Nuclear Waste. Current Scientific Opinion on Disposal. Procedural Decisions in Canada. Impact Assessment. The Radionuclides and Their Behaviour. The Canadian Proposal. Topics not included in this book

2- Nuclei and Radioactivity
The Structure of the Nucleus. Neutrons, Protons and Nuclei. Nuclear Mass and Size. Nuclear Energy and Mass. Stable and Unstable Nuclei. The Phenomena of Radioactivity. In Summary. Interaction with Materials: Shielding. Radioactive Decay and Half Life. Measurement of Radiation. Detection Instruments. The Measurement of Radioactivity. The Measurement of Radiation Dose. Normal Background Radiation Doses. Human Health Effects

3- Nuclear Reactions and Reactors
Nuclear Reactions. Neutron Capture. Nuclear Fission. Some History of Nuclear Fission. The Products of Nuclear Fission. Multiple Neutron Capture. Chain Reactions. Nuclear Reactors. Reactor Control. Nuclear Bombs. Spent Fuel

4- The Spent Fuel
Construction and Composition. Current Inventory and Storage of Fuel Bundles. The Fission Products. The Activation Products. The Actinide Elements. Typical Final Composition. Chemical Properties of Waste Radionuclides. Important Nuclear Reactor Products and Their Chemical Forms. Location of the Radionuclides in the Fuel. Dissolution of the Fuel. Heat Production

5- Proposed Management Methods
Pre-treatment Methods. Some Unacceptable Proposals. Transmutation. Transmutation: Technical Background. Practical Options for Transmutation. Accelerator-induced Transmutation. Summary and Conclusions on Nuclear Trans-mutation. An Acceptable Proposal. Geological Disposal. The Multi-barrier System. Remaining Ethical Questions. Whether or not to continue monitoring. What levels of radiation are acceptable?. What time span should be considered?

6- Geological Disposal
Requirements. Seismic History. The Multi-barrier concept. The Canadian Proposal. The Barriers. Emplacement. Ground Water. Container. Sheathing. The Buffer. The Rock. Sealing The Results. Some Uncertainties

7- The Critical Processes
Attack by Ground Water. Resaturation. Container Corrosion and Failure. Corrosion of the Sheathing. Radionuclide Escape. Chemical Properties of the waste radionuclides. Radionuclide Release from the Used Fuel. Instant Release. Migration through the Engineered Barriers. Radionuclide Migration through The Buffer and Backfill. Migration into and through the Natural Barriers. The Geosphere. Migration in Intact Rock - The Waste. Exclusion Zone. Migration into and Through the Natural Barriers. Ground Water Flow. Isotope Dilution. Dilution and Dispersion in the Biosphere. Tracing Radionuclides Through the Barriers. The Time Scale. The Importance of Half Life. Chemical Holdups. A Study of Individual Radionuclides. Short-lived Radionuclides. Elements Likely to be Trapped Within the UO2 Crystal Lattice. Radionuclides Likely to Escape the Lattice but Likely to be Trapped by the Buffer. Mobile radionuclides. A Final Reckoning. Some Technically Sensitive Points

8- Forecasting the Impact
Precision of the Requirements. The Challenge. Forecasting Methods. Calculations: Probabilistic Calculations. Deterministic Calculations. Estimation of the Barrier Transit Times. Results. Accuracy and reliability of the data

9- Final Comments
Summary. Resaturation. Container Corrosion. Site Rejection Criteria. Caveats Arising From the Assumptions. Conclusions

10- The Last Word
Proof of Burial's Not So Easy

Radioactivity Units Conversion Factors. The Chemical Elements. The Mathematics of Trans-mutation. Miscellaneous Calculations. The Iodine Dilemma. Useful Websites