Radioisotope Techniques for Problem-Solving in Industrial Process Plants

326 Pages·1986·8.454 MB·English

by  J. S. Charlton (auth.), J. S. Charlton (eds.)

RADIOISOTOPE
TECHNIQUES
FOR PROBLEM
SOLVING IN
INDUSTRIAL
PROCESS
PLANTS
RADIOISOTOPE
TECHNIQUES
FOR PROBLEM
SOLVING IN
INDUSTRIAL
PROCESS
PLANTS
Edited by
J. S. CHARLTON
Physics and Radioisotope Services
Imperial Chemical Industries PLC
Billingham, Cleveland, UK
Leonard Hill
Glasgow and London
Published by Leonard Hill
A member of the Blackie Group
Bishopbriggs
Glasgow G64 2NZ
Furnival House
14-18 High Holborn
London WCIV 6BX
Copyright © 1986 John Stuart Charlton
First published 1986
Softcover reprint of the hardcover Ist edition 1986
All rights reserved.
No part of this publication may be reproduced,
stored in a retrieval system, or transmitted,
in any form or by any means
electronic, mechanical, recording or otherwise,
without the prior permission of the copyright holder.
British Library Cataloguing in Publication Data
Radioisotope techniques for problem-solving
in industrial process plants.
1. Process control 2. Radioisotopes
I. Charlton, J .S.
670.42'7 TS156.8
ISBN-13: 978-94-010-8306-5 e-ISBN-13: 978-94-009-4073-4
DO I: 10.1 007/978-94-009-4073-4
Photosetting by Thomson Press (India) Limited.
Contents
1 Radioisotopes in industry J. S. Charlton
1.1 Introduction I
1.2 Historical perspective 2
1.3 Current uses of radioisotopes in problem-solving 5
1.4 Growth trends and the future 7
References 8
2 The basic physics of radioactivity E. A. Edmonds 9
2.1 Introduction 9
2.2 The structure of the atom 9
2.3 Isotopes 10
2.4 Ionizing radiations 11
2.5 Important concepts in radioactivity 19
2.6 Properties of radiations-interactions with matter 23
Select bibliography 29
3 Radiation detection K. James 30
3.1 Introduction 30
3.2 Methods of detection 30
3.3 The Geiger counter in more detail 35
3.4 The scintillation counter in more detail 41
3.5 Pulse processing equipment 45
4 Radioactive sources T. L. Jones 48
4.1 Production of radioactive sources 48
4.2 Radioisotopes from natural sources 49
4.3 Fission products 51
4.4 Neutron activation 52
4.5 Cyclotrons and accelerators 55
4.6 Radionuclide generators 56
References 57
5 Biological effects of radiation J. S. Charlton 58
5.1 Introduction 58
5.2 Ionizing radiations 58
5.3 Harmful effects of radiation: historical perspective 58
5.4 Radiological protection: historical perspective 59
5.5 Radiation dose 60
5.6 The hazards of ionizing radiations 61
5.7 Dose and risk 63
VI CONTENTS
5.8 ICRP recommendations 64
5.9 Doses in perspective 67
5.1 0 Conclusions 69
References 70
6 Radiological protection G. Reed 71
6.1 Protection against external radiation 72
6.2 Protection against internal radiation 79
6.3 Conclusions S3
7 Radioactive tracer applications T. L. Jones 84
7.1 Half-life 84
7.2 Specific activity 85
7.3 Type of radiation 86
7.4 Energy of radiation 87
7.5 Physical and chemical behaviour 89
7.6 Planning a radioisotope tracer investigation 90
References 96
8 Measurement of flow using radioactive tracers P. Johnson 97
8.1 Introduction 97
8.2 Pulse velocity method 98
8.3 Dilution methods 100
8.4 Application of radiotracer flow methods 104
References III
9 Measurement of residence times and residence-time distributions
G. Reed 112
9.1 Introduction 112
9.2 Flow through ideal reactors 113
9.3 Flow through non-ideal reactors 114
9.4 Models for non-ideal flow 116
9.5 Calculation of parameters 119
9.6 Diagnosing malfunctions of process equipment 122
9.7 Equipment arrangement for measurement of RTD using radio tracers 125
9.8 Case histories 126
References 13 7
10 Leakage detection R. Roper 138
10.1 Introduction 138
10.2 Leak detection techniques 138
10.3 Description of radiotracer techniques 141
10.4 Detection equipment 148
10.5 Case histories 149
11 Miscellaneous radiotracer applications G. Reed 167
11.1 Mixing and blending studies 167
11.2 Measurement of volume 176
CONTENTS VB
11.3 Ventilation studies using radioisotopes 179
11.4 Line pigging 181
11.5 Corrosion and wear studies 183
References 187
12 Sealed-source applications J. S. Charlton 188
12.1 Introduction 188
12.2 Types of sealed source 189
12.3 Selection of measurement techniques 200
References 202
13 Gamma-ray absorption techniques J. S. Charlton 204
13.1 Introduction 204
13.2 Equipment for plant applications 205
13.3 Thickness measurement 207
13.4 Density measurement 214
13.5 Measurement of mass per unit area 221
13.6 Case histories 230
References 245
14 Radiation scattering techniques E. A. Edmonds 247
14.1 Introduction 247
14.2 Radiation scattering processes 248
14.3 Industrial applications 250
14.4 Case studies 252
References 268
15 Neutron techniques J. S. Charlton 269
15.1 Introduction 269
15.2 Neutron interactions 269
15.3 Techniques based upon neutron moderation 274
15.4 Neutron absorption techniques 282
15.5 Neutron activation techniques 285
15.6 Radiological protection aspects 288
15.7 Case histories 292
References 303
Appendix: Radiation measurement-statistical considerations K. James 305
A. I Introduction 305
A.2 Counting statistics 305
A.3 Correlation of sets of observations 306
A.4 Precision of a single measurement 307
A.5 Standard deviation of a ratemeter 308
A.6 Error propagation 308
A.7 Effect of background 309
A.8 Statistics of pulse height distributions 310
A.9 Detector efficiency 311
References 311
Index 313
Contributors
J. S. Charlton, BSc, PhD
Manager, Plant Services and Instruments, Physics and Radioisotopes
Research Group
E. A. Edmonds, BSc, MSc, PhD
Process Applications Manager, Physics and Radioisotope Services Group
K. James, BSc, PhD
Nucleonic Instruments and Development Manager, Physics and Radio
isotope Services Group
P. Johnson, BSc, FInstP
Former Group Manager, Physics and Radioisotope Services, and Past
President, Tracerco Corporation
T. L. Jones, BSc, PhD
North-west Area Manager, Physics and Radioisotope Services Group
G. Reed
Radiological Protection Manager, Physics and Radioisotopes Research
Group
R.Roper
Radiation Scientist, Physics and Radioisotope Services Group
1 Radioisotopes in industry
J. s. CHARLTON
1.1 Introduction
Radioactive materials, as sealed sources of ionizing radiation and as
radioactive tracers, are used extensively throughout industry. The field of
application is extremely wide: this book is concerned with the application of
radioisotope techniques to process investigation on full-scale industrial plant.
Our objective is to explore the many ways in which radioisotopes can be used
to help industrial plant to operate more efficiently. Because of the sheer
volume and diversity of radioisotope applications, a selective approach has
been adopted. We have concentrated upon those applications which have
proved to be the most useful in terms of economic benefit, realized either as
savings or as improved production efficiency.
As with any technology it is, of course, possible to achieve the benefits
without a detailed understanding of the basic principles,just as one can make
good use of an automobile with little or no knowledge of the workings of the
internal combustion engine! Some understanding of the basics is nevertheless
essential if one is to use the technology to its full effect and, equally
importantly, appreciate its limitations. This background information is
presented, in condensed form, in Chapters 2-4.
Safety is clearly a further important consideration. It is well known that
unrestricted exposure to radioactive materials can lead to health detriment.
However, it also needs to be appreciated that these hazards are well
understood and that through appropriate precautions they can be reduced to
a negligible level. Chapters 5 and 6 discuss health physics and radiological
protection and describe briefly the practical measures which are taken to
protect both workers and public.
The remainder of the book is devoted to the process applications of
radioisotopes. Each chapter covers one technique or class of techniques.
Both theory and experimental approach are described and, in addition, case
histories are presented which, as well as illustrating the versatility of the
technology, demonstrate the economic benefits which can be realized.
In describing case histories and in examining several other aspects of
radioisotope applications technology we have drawn upon the experiences
of two organizations-the Physics and Radioisotope Services Group (PRS)
of Imperial Chemical Industries PLC, and its associate company, Tracerco
Corporation of Houston. PRS was established some 30 years ago solely to
2 RADIOISOTOPE TECHNIQUES
exploit radioisotope technology, and, together with Tracerco, provides
service to a broad spectrum of industry world-wide. It is the world's largest
organization specifically devoted to providing contract problem-solving
services using radioisotopes, and its activities will exemplify what radioisotope
technology can achieve.
1.2 Historical perspective
It is now almost ninety years since BecquereP discovered the phenomenon of
radioactivity. For fifty years thereafter, the use of radioactivity was virtually
confined to medical, research, military and power-generation applications.
However, in the late 1940s and 1950s the increasing availability of man-made
radioisotopes produced in nuclear reactors resulted in a greatly expanded
sphere of application. The oil industry, in particular, was quick to appreciate
the potential of radioisotope techniques-the first recorded industrial use of
radioisotopes involved oil-well tracer studies 2.
Research institutes and industrial companies world-wide began to explore
potential uses of radioisotopes and ionizing radiations. To examine the factors
1950s
I
: General interest in radiation processing. Team established
I
II : to investigate value of this
: Worldwide research stimulated by : I
I technology to lei (mid-1950o)1
I I I I
: availability of sources of ionizing radiation.:
I
I
I
I
I
I
I
I I
I I Team becomes centre
I : I
Development of new and improved :of radioisotope expertise in leI.:
radioactive sources and methods I
I
of radiation detection. I
I
I I
I I
I I
I I
I Late 19505 to mid-1960s
I
I
I
II R&D applications. II Use of sealed and
Radiolabelled I unsealed sources of
Evolution of radioisotope techniques both I
compounds in I radiation in plant and
: for research and engineering applications. laboratory studies. : process investigation.
I I
Figure 1.1. The origin of a radioisotope applications service.
RADIOISOTOPES IN INDUSTRY 3
which shaped the development of the technology, it is instructive to refer to our
example of ICI's Physics and Radioisotope Services Group. Within ICI,
interest was initially centred upon the possibility of using sources of ionizing
radiation to induce chemical reactions (Figure 1.1). The findings here were not
as encouraging as had been hoped. Though radiation processing possessed
unique advantages in a limited number of situations, in the majority of cases
large-scale radiation sources could not compete with conventional process
technologies. However, while radioisotopes as a processing tool appeared to
have limited use, it was already clear that there was considerable scope for
them in process investigation, and that it was this sphere of activity which
possessed the greatest potential for economic benefit.
The ICI Group was fortunate in being located at Billingham in the north
east of England, at the centre of one of the largest chemical complexes in
Europe, and benefited greatly from close association with production
personnel-a classic case of 'solutions in search of problems' and 'problems in
search of solutions' being brought together in close proximity.
Considerable savings resulted through using radioisotope techniques to
investigate operational characteristics and to diagnose faults on full-scale
process plant. An important feature was the unique ability conferred by the
properties of ionizing radiation to investigate problems without disrupting the
process in any way. In particular, shutdown time could be avoided or reduced
to a minimum. Process applications activity was therefore considerably
stimulated by the construction, accelerating throughout the 19 60s and 1970s,
of very large single-stream production units (Figure 1.2). The financial con
sequences of shutdown of a unit of size comparable (say) with that of the
500000 te p.a. No.5 Olefines Plant at Wilton, Cleveland, were so large that a
considerable investment of time and resources was made in on-line sur
veillance and fault-finding techniques, among which radioisotope methods
were found to be by far the most versatile.
By 1970, the use of radioactive tracers had become routine to the extent that
PRS Group could economically justify the purchase of its own radioisotope
production facility, a TRIGA Mark I nuclear reactor. This was installed at the
Group's headquarters in 1971 and continues to function as a safe and reliable
source of radioisotopes. As is often the case, meeting the existing need (by the
purchase of the nuclear reactor) stimulated an even greater demand: tracer
applications which had hitherto been impossible because they depended upon
the availability of a particular radiotracer (for example, material of very short
half-life) became feasible, and further expansion of process applications
resulted.
Continued development of this technology throughout the 1970s was
directed more by economic than technical influences. Concerns about the
continued availability and conservation of fossil fuel resources (especially oil
and gas) led to the extensive use of radioisotope techniques to provide the
basic information for energy-conservation studies. Additionally, and very
B