Pacoma

European Commission Directorate-General For The Information Society And Media Directorate-General For Research And Innovation

Description

Performance assessment of the confinement of medium-active and alpha-bearing wastes: Assessment of disposal in a clay formation in the United Kingdom
Nuclear energy and safety

Informations

• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-INFORMATION-SOCIETY-AND-MEDIA-DI
• Nombre de lectures: 14
• Langue: English
• Poids de l'ouvrage: 6 Mo

Extrait

Commission of the EuroDean Communities
Pacoma:
Performance assessment of the confinement
of medium-active and alpha-bearing wastes
Assessment of disposal in a clay formation in the United Kingdom
Ξ HE Commission of the European Communities
Pacoma:
Performance assessment of the confinement
of medium-active and alpha-bearing wastes
Assessment of disposal in a clay formation in the United Kingdom
S.F. Mobbs,1 R.A. Klos,1 J.-S. Martin,1 J.-M. Laurens,2 K.H. Winters,3
J.M. Bealby,4 G. Dalrymple4
1 National Radiological Protection Board (UK)
2 Electrowatt Engineering Services Ltd (UK)
3 AEA Technology, Harwell (UK)
4 Principia Mechanica, YARD Ltd (UK)ι
Final report
Study performed under contracts FI1W/0041, FI1W/0047 FI1W/0043 and FI1W/0042 in the framework of the
European Atomic Energy Community's R&D programme 'Management and storage of radioactive waste',
Task 5: 'Safety of geological disposal - Pacoma project'.
Directorate-General
Science, Research and Development
1991 A/^ 'l·S ^ ° EUR 13143 EN 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
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1991
ISBN 92-826-2163-4 Catalogue number: CD-NA-13143-EN-C
© ECSC-EEC-EAEC, Brussels · Luxembourg, 1991
Printed in Luxembourg Abstract
This report describes the PACOMA assessment of the radiological
impact of disposal of intermediate level and alpha-bearing wastes in a
hypothetical repository situated in the clay formations below the
Harwell site in the United Kingdom. The assessment includes: best
estimate calculations, uncertainty analyses, sensitivity analyses and
model comparisons. Results of the radiological impact calculations
are in the form of doses and risks to individuals and time-integrated
doses to populations, for a normal evolution scenario and a number of
altered evolution scenarios.
The calculated risks to individuals are well below the limit
recommended by the ICRP, and the calculated collective dose over the
first 10,000 years after disposal is zero. Thus the radiological
impact of the disposal intermediate level and alpha-bearing wastes in
a clay formation is predicted to be small. The uncertainty analyses
showed that, for the normal evolution scenario, the range of predicted
risks to individuals is very wide. However, these results must be
treated with caution because a formal methodology for eliciting
judgements about model parameter values was only applied in the case
of geosphere data. The sensitivity analyses and model comparisons
indicated the need for improved models and data for water and
radionuclide movement in the near-surface environment. Contributors to the Report
S F Mobbs, NRPB ­ Chapters 1, 2, 3, 6, 7, 8, 9, 11
R A Klos», NRPB ­ s 6, 7, 8, 9, 11
J S Hartin, NRPB ­ Chapters 6, 7, 9
J­M Laurens, EWE ­ s 4, 11
Κ Η Winters, AEA Technology ­ Chapters 5, 11
J M Bealby, Principia Mechanica ­ Chapter 10
G Dalrymple, a Mecanica ­ Chapter 11
Notice of the authors :
"This report has been produced in the interests of providing as much
information as possible about the UK assessment for the PACOMA project.
Those parts for which NRPB is the sole author have not been subject to
the full NRPB internal approval procedures."
*Now at the Paul Scherrer Institut, Würenlingen, Switzerland
IV ­CONTENTS
Page No.
1 1. INTRODUCTION
9 2. WASTE INVENTORY
21
3. ASSESSMENT METHODOLOGY
29
4. THE NEAR FIELD
37
5. THE FAR FIELD
149 6. THE BIOSPHERE
191 7. RESULTS OF THE BEST ESTIMATE CALCULATIONS
235 8. UNCERTAINTY ANALYSES
271 9. SENSITIVITYS
317
10. COMPARISON OF MODELLING APPROACHES
361 11. SUMMARY AND CONCLUSIONS
APPENDIX A - Description of MiniBIOS and Details of
Uncertainty Analysis Results 375
V -Chapter 1
INTRODUCTION
S F Mobbs
National Radiological Protection Board
1 -