Application of assay technology

European Union

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Nuclear energy and safety

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• Publié par: EUROPEAN-UNION
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 3 Mo

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ISSN 1018-5593
* *
Commission of the European Communities
Radioactive waste package assay facility
Volume 1
Application of assay technology
Task 3
Characterization of radioactive waste forms
A series of final reports (1985-89)
No 40
Report
EUR 13870/1 EN i'
Commission of the European Communities
nuclear science
and technology
Radioactive waste package assay facility
Volume 1
Application of assay technology
Task 3
Characterization of radioactive waste forms
A series of final reports (1985-89)
No 40
D. J. S. Findlay,1 T. H. Green,2 T. V. Molesworth,2 D. Staniforth,2
N. R. Strachan,2 M. 0. Wise,3 K. R. Forrest,4 J. D. Rogers5
1 Harwell Laboratory, Oxfordshire 0X11 ORA, United Kingdom
2 Taylor Woodrow UK (contractor)
3 Siemens Plessey Controls UK
4 Ray Technologies UK
5 Rolls Royce UK
This report was prepared for the European Atomic Energy Community's
cost-sharing research programme on radioactive waste management and
disposal (Task 3 — Section 5)
Contract No FM W0102/0244 UK
Final report
Directorate-General I piai "
EUROP. Biblioth. Science, Research and Development
1992 N'EuR 13870/1 EN
CI. Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
L-2920 Luxembourg
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting on
behalf of the Commission is responsible for the use which might be made of the
following information
ISBN 92-826-3633-X (Volumes 1-3)
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1992
ISBN 92-826-3634-8
© ECSC-EEC-EAEC, Brussels • Luxembourg, 1992
Printed in Belgium ABSTRACT
This report, in three volumes, covers the work carried out by Taylor
Woodrow Construction Ltd., and two major sub-contractors - Harwell
Laboratory (AEA Technology) and Siemens Plessey Controls Ltd., - on the
development of a radioactive waste package assay facility, for cemented
500 litre intermediate level waste drums.
In Volume 1, the reasons for assay are considered together with the
various techniques that can be used, and the information that can be
obtained. The practical problems associated with the use of the various
techniques in an integrated assay facility are identified, and the key
parameters defined. Engineering and operational features are examined
and provisional designs proposed for facilities at three throughput levels
- 15,000, 750 and 30 drums per year respectively.
The capital and operating costs for such facilities have been estimated.
A number of recommendations are made for further work.
— ill — CONTENTS
PREFACE XI
GLOSSARY OF ABBREVIATIONS xiil
1.0 INTRODUCTION 1
1.1 Outline of Research Programme
1.2 The Original "I.R.I.S" Concept 2
2.0 BASIC ASPECTS OF WASTE ASSAY 5
2.1 Definition of Intermediate Level Waste
2.2 Waste Arisings and Facility Cycle Time
2.3 The Need for Assay 6
2.4 Main Features of Proposed Assay Techniques 10
2.4.1 General 1
2.4.2 High Energy (Gamma) Radiography1
2.4.3 Passive Neutron Counting
2.4.4 Gamma Spectroscopy3
2.4.5 Active Neutron Interrogation
2.4.6e Gamman4
2.5 Limits of Detection
2.5.1 Introduction
2.5.2 High Resolution Gamma Spectroscopy 15
2.5.3 Gamma Interrogation 1
2.5.4 Neutronn
2.5.5 Passive Neutron Counting
2.6 Location of Assay Facility6
2.7 Nature and Use of Information from Assay 23
2.7.1 General 2
2.7.2 Information from Gamma Emissions
2.7.3nm Passive Neutron Counting 25
2.7.4n from Active Interrogation
2.7.5nm Gamma Radiography
2.7.6 Effects of Types of Waste on Assay Data 27
2.7.7 Uses of Assay Data8
2.7.8 Other Assay Processes9
2.7.9 Effects of Delays in Application of Assay 31
2.7.10 Beta Detection 3
2.8 Ancillary Requirements of Assay Facility 32
2.8.1 Introduction
2.8.2 Package Identification
2.8.3 Surface Contamination
2.8.4e Dimensions3
2.9 The Main Features of the Research Programme 34
2.9.1 Objectives 3
2.9.2 Practicability of Proposed Technology5
— v — 3.0 ACTIVE NEUTRON AND ACTIVE GAMMA INTERROGATION 37
3.1 Introduction 3
3.2 Stage 1 - Desk Study
3.3e 2 - Experimental Work8
3.4 Results of Active Neutron Interrogation Investigation 41
3.4.1 Neutron Generating Target 4
3.4.2 Thermal Neutron Flux1
3.4.3n Detection
3.4.4 Characteristic Neutron Responses2
3.4.5 Detection Sensitivity3
3.5 Results of Active Gamma Interrogation Investigation 4
3.5.1 Neutron Detection 4
3.5.2 Characteristic Neutron Responses4
3.6 Basic Designs of Stations for Active Interrogation 45
4.0 DATA PROCESSING 49
4.1 General
4.2 Aim of Data Processing
4.3 Data Processing Methods 51
4.3.1 The Naive Method
4.3.2 The Axiomatic method
4.4 Data Processing Model2
4.5 Implementation 53
5.0 GAMMA SPECTROSCOPY7
5.1 Introduction
5.2 Basis of method
5.3 Operation 60
5.4 Interference from Other Radiation Sources 6
5.5 Results Expected2
5.6 Multiple Detectors
— VI — 6.0 GAMMA RADIOGRAPHY 65
6.1 Introduction
6.2 Design Features of Radiographic Unit 6
6.2.1 Basic Configuration
6.2.2 Imaging Process 67
6.2.3 Radiographic Image Standards
6.2.4 Image Definition9
6.2.5 Radiation Intensity
6.2.6 -n Level from Linac-Target 70
6.2.7 Image Improvement 71
6.3 Other Features2
6.3.1 Comparison with Known Inhomogeneities
6.3.2 Effects of Drum Rotation
6.4 Results Obtained
7.0 LINAC AND TARGETS 75
7.1 General Requirements
7.2 Description of Linac
7.2.1 Basis of Operation
7.2.2 Linac Components8
7.3 Linac Configuration for Integrated Assay Facility 7
7.3.1 General
7.3.2 Gamma Radiography 79
7.3.3 Active Interrogation
7.3.4 Use of a Single Linac 80
7.4 Previous Linac Experience
7.5 Costs and Power Requirements1
7.6 Reliability of Linacs
7.7 Location of Linac(s) within Facility 8
8.0 APPLICATION OF TECHNOLOGY 83
8.1 Introduction
8.2 Assay System Specification
8.2.1 General
8.2.2 Mean Matrix Density
8.2.3 Homogeneity of Matrix
8.2.4 Passive Neutron Count6
8.3 Package Acceptance Criteria 8
8.3.1 Actinide Levels
8.3.2 Effect of High Individual Package Activity 8
8.3.3 Need for Assay of Everye7
8.3.4 Physical Integrity8
8.4 Passive Neutron Examination
— VII — 8.5 The Integrated Assay System 89
8.5.1 Introduction 8
91 8.5.2 Number of Examination Stations
93 8.5.3 Use of Combined Examination Stations
96 8.5.4 Assay Time
96 8.5.5 Cyclee
97 8.5.6 Number of Linacs
97 8.5.7 Operational Sequence Diagrams
99 8.5.8 Utilisation 9 Processinge 100
100 8.5.10 Review of Main Parameters
104 1 Number of Packages inside Facility
105 8.5.12 Shielding Requirements
8.6 Assay Mobility 106
8.7 Low Throughput Systems 106
9.0 DESIGN AND OPERATIONAL FEATURES OF PRACTICAL ASSAY FACILITY 109
9.1 General 10
9.2 Access to Shielded Enclosure9
9.3 Viewing Systems
9.4 Services 111
9.4.1 General
9.4.2 Electricity
9.4.3 Cooling Water2
9.4.4 Compressed Air
9.4.5 Ventilation
9.5 Miscellaneous Points4
9.5.1 Overall Layout Considerations 11
9.3.2 Calibration Packages
9.5.3 Unusual Packages 115
9.5.4 Materials of Construction6
9.6 Throughput Rates and Operating Times
9.6.1 Drum Marshalling
9.6.2 Cycle Time Calculation7
9.6.3 Overall Operating Parameters8
9.7 Drum Handling 11
9.7.1 Introduction
9.7.2 Powered Roller Conveyors 119
9.7.3 Twin Strand Chain Conveyor 120
9.7.4 Roller Bed Beltr
9.7.5 Twin Track Roll.er Conveyor, with Central
Chain Driven Conveyor
9.7.6 Twin Track Roller, with Central
Pneumatic Pusher1
9.7.7 Twin Strand Chain Conveyor, Drum Horizontal 12
9.7.8 Powered Roller, Druml
9.7.9 Ball Units with Central Drive Rollers, Drum
Horizontal ' 12
— VIII —