Conditioning of cladding waste for long-term storage by press compaction and encapsulation in lead containment

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

Description

Nuclear energy and safety
Environment policy and protection of the environment

Informations

• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-INFORMATION-SOCIETY-AND-MEDIA-DI
• Nombre de lectures: 19
• Langue: English
• Poids de l'ouvrage: 7 Mo

Extrait

Commission of the European Communities
nuclear science
and technology
Conditioning of cladding waste
for long-term storage
by press compaction and
encapsulation in lead containment
Report
EUR 10824 EN Commission of the European Communities
nuclear science
and technology
Conditioning of cladding waste
for long-term storage
by press compaction and
encapsulation in lead containment
P. de Regge
SCK/CEN
Studiecentrum voor Kernenergie
Centre d'étude de l'énergie nucléaire
Mol (Belgium)
Final report
Work performed under contract No WAS-307-83-2-B (RS) in the scope of
the indirect action programme of the European Atomic Energy Com­
munity on the management and storage of radioactive wastes
Directorate-General
Science, Research and Development
1986 EUR 10824 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting on
behalf of then 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, 1987
ISBN 92-825-6680-3 Catalogue number: CD-NA-10824-EN-C
© ECSC-EEC-EAEC, Brussels · Luxembourg, 1987
Printed in Luxembourg CONTRIBUTIONS
This research and development work has been carried out with
contributions from the Nuclear Chemistry Department, from the
Laboratories for High and Medium Activities, from the Metallurgy
Department and from the Technical Services Workshop.
The contributions of P. Beullens, A. Daniels, S. de Burbure,
P. De Meyer, A. De Roost, J. Marien and J. Vaesen, are hereby
gratefully acknowledged.
Design and construction of the containers were subcontracted to
Metallurgy Hoboken Overpelt and those works were co-ordinated by
M. Meeus.
Ill PREFACE
The reprocessing of spent fuel from power reactors based on the current
chop- and leach technology produces a solid waste product of cladding hulls
and other metallic residues. This type of waste deserves serious concern on
account of the voluminous amounts involved and the high levels of associated
radioactivities, as well short-living fission and activation products as
long-lived actinides. Economical and safety requirements call for the condi­
tioning of this low density highly active metal scrap in an appropriate
form.
With a view of making suitable conditioning processes available to large-
scale fuel reprocessing installations in the member states of the European
Community, the Commission of the E.C. initiated and sponsored research and
development work in this field through the indirect action programme of the
European Atomic Energy Community.
The proposed alternative to the current practices of storing the waste in
immersed silos or cementing it concerns the press compaction for reduction of
the volume followed by conditioning of the compacted products in a matrix or
a suitable containment to delay leaching of the associated radioactivity.
Embedment of the waste in a matrix of low-melting alloys has been considered
within the framework of a study carried out during 1975-1979. This technique
has been developed and tested with radioactive materials during 1980-1983 but
was finally abandoned because of secundary effects. During this research
however the important volume reductions of the waste by press compaction have
been recognized and the excellent corrosion resistance of some of the alloys
in a typical waste repository environment has been observed. As a result
those qualities have been combined in a new concept involving the press com­
paction of the waste and its conditioning in a containment form which incor­
porates the corrosion resistant materials as essential features for delaying
the release of radioactivity into the environment. The development and demon­
stration of this concept in nonradioactive conditions, at a pilot scale forms
the object of the research and development studies reported here. TABLE OF CONTENTS
Page
CONTRIBUTIONS Ill
PREFACE V
ABSTRACT IX
1. INTRODUCTION 1
2. OPTIMIZATION OF THE 300 t PRESS FOR SHIELDED CELL OPERATION ....i.. 2
2.1. Construction of the demonstration unit 2
2.2. Remote operation and maintenance of the press
2.2.1. The main features of the 300 T press
2.2.2. Removal of the anvil 3
2.2.3.l of the die 4
2.2.4. Removal of the ram
2.2.5.l of the die base plate
2.3. Synoptic control panel
3. OPTIMIZATION OF THE ENCAPSULATION IN A LEAD/STAINLESS STEEL
CONTAINMENT 5
3.1. Preliminary design criteria for the container 6
3.1.1. Temperature profile of the conditioned waste
3.1.2. Strength and penetration depths for the welded parts 7
3.1.3. General design specifications 8
3.2. Design and construction of the pilot-scale container
3.2.1. The inner container
3.2.2. The outerr 9
3.3. Tests performed on the outer container 10
3.3.1. Non-destructive testing of the lead inner part 1
3.3.2. Destructive testing of the lead inner part
3.3.3.e testing of the stainless steel
outer part 11
VII Page
3.4. Development of a welding procedure for remote operation in
the shielded cell 11
3.4.1. Selection of the welding procedure 1
3.4.2. Welding tests on the inner container2
3.4.3.gs on the leadr3
3.4.4. Welding tests on the outer stainless steel container 14
4. DEMONSTRATION OF THE CONDITIONING OF CLADDING WASTE IN A
SHIELDED CELL MOCK-UP 14
4.1. Transfer unit for the hulls5
4.2. The vacuum testing chamber
4.3. The characteristics of the welding unit 1
4.3.1. The power source
4.3.2. The welding torch
4.3.3. Theg frame 16
4.4. Demonstration of the conditioning concept
4.5. Preliminary design of an industrial container 37
5. CONCLUSIONS 3
TABLES9
FIGURES 41
VIII