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Welding of the lid and the bottom of the disposal canister

Technical Report:

Abstract

The seal welding of the lid and bottom of a copper disposal canister for spent nuclear fuel using ordinary electron beam welding (EBW) made in a vacuum and the results gained in the development work are presented in this report. As an alternative method, the friction stir welding (FSW) is also presented in an overview. Welding of copper is very challenging mainly due to the high thermal conductivity of the copper material. The EBW method is based on so-called deep penetration welding which does not use additional welding material. The convenience of the method is that the weld is the same material as the base material. When compared to other fusion welding methods, the material transitions in the material caused by EBW are slight. The EBW process typically has a high number of welding parameters but, in practice, only a few parameters are adjusted during copper welding to maintain weld quality and the stability of the process. The high vacuum required by the method prevents the material from oxidising but, on the other hand, it narrows the application of the method. The requirements presented for the weld and welding process can be divided in two classes. The first class contains  More>>
Authors:
Meuronen, I; [1]  Salonen, T
  1. Meuro-Tech, Tampere (Finland)
Publication Date:
Oct 15, 2010
Product Type:
Technical Report
Report Number:
POSIVA-10-05
Resource Relation:
Other Information: 43 refs.
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 42 ENGINEERING; SPENT FUELS; CONTAINERS; RADIOACTIVE WASTE DISPOSAL; UNDERGROUND DISPOSAL; SEALS; COPPER; ELECTRON BEAM WELDING; VACUUM WELDING
OSTI ID:
1010731
Research Organizations:
Posiva Oy, Helsinki (Finland)
Country of Origin:
Finland
Language:
English
Other Identifying Numbers:
Other: ISBN 978-951-652-176-6; TRN: FI1104005
Availability:
Available in fulltext at http://www.posiva.fi/files/1434/POSIVA_2010-05_web.pdf or as a soft back edition from Posiva Oy, Olkiluoto, 27160 Eurajoki, Finland, tel. +358-2-837231
Submitting Site:
FIN
Size:
90 p. pages
Announcement Date:
Apr 11, 2011

Technical Report:

Citation Formats

Meuronen, I, and Salonen, T. Welding of the lid and the bottom of the disposal canister. Finland: N. p., 2010. Web.
Meuronen, I, & Salonen, T. Welding of the lid and the bottom of the disposal canister. Finland.
Meuronen, I, and Salonen, T. 2010. "Welding of the lid and the bottom of the disposal canister." Finland.
@misc{etde_1010731,
title = {Welding of the lid and the bottom of the disposal canister}
author = {Meuronen, I, and Salonen, T}
abstractNote = {The seal welding of the lid and bottom of a copper disposal canister for spent nuclear fuel using ordinary electron beam welding (EBW) made in a vacuum and the results gained in the development work are presented in this report. As an alternative method, the friction stir welding (FSW) is also presented in an overview. Welding of copper is very challenging mainly due to the high thermal conductivity of the copper material. The EBW method is based on so-called deep penetration welding which does not use additional welding material. The convenience of the method is that the weld is the same material as the base material. When compared to other fusion welding methods, the material transitions in the material caused by EBW are slight. The EBW process typically has a high number of welding parameters but, in practice, only a few parameters are adjusted during copper welding to maintain weld quality and the stability of the process. The high vacuum required by the method prevents the material from oxidising but, on the other hand, it narrows the application of the method. The requirements presented for the weld and welding process can be divided in two classes. The first class contains the requirements intended to ensure the long-term safety of the canister. Corrosion resistance and adequate creep ductility are such requirements. The second class requirements correspond to welding process requirements for component manufacture, the components themselves and the other processes of the encapsulation plant. The welding process, including the personnel, equipment and process validation, shall also fulfil the special requirements concerning all nuclear plants in general. The quality assurance and control (QA/QC) for welding is presented as a separate section. The welding quality assurance contains the personnel, equipment and the welding process. For EBW process validation there are available norms and acceptation procedures. In these, the essential component is the validation of preliminary (pWPS) and ordinary welding procedures. The quality of the welds has, so far, shown to be adequate in spite of the fact that the optimisation of the welding process is still uncompleted. During the reporting of this development work, the statistical data available has not been sufficient to make the capability analysis of the flawlessness of the welds. The FSW method has been considered as an alternative welding method. This method has been selected as the primary sealing method by the Swedish company for spent nuclear fuel management, SKB. In spite of the fact that this method is quite new, the SKB results in using this method have been good and the weld fulfils the long-term safety requirements. The development of the automation of the control system of the FSW method is still unfinished, but it is expected that the development work can be completed in a few years. (orig.)}
place = {Finland}
year = {2010}
month = {Oct}
}