RD&D-Programme 2004 - SKB

The development work on nondestructive testing (NDT) of the canister’s components is based
on the testing activities of different suppliers, as well as the experience being accumulated at
the Canister Laboratory. An inventory has been made of equipment, methods and know-how.
So far the work has focused on the copper shell and the insert. There is as yet no NDT of certain
parts such as copper lid and bottom, channel tube and steel lid with bolt. Work is planned to
clarify which type of testing is required and to develop and apply a methodology. The intention
with regard to the canister’s copper components and insert parts is to complete studies and
specifications during 2004. Approved NDT resources for testing of the most important canister
components will be available during 2005.
The aim during 2004 is to prepare descriptions of the defects that can arise in different stages
of the production system. Based on these descriptions, together with reliability studies for NDT
and probabilistic strength analysis of the insert, preliminary acceptance criteria for the canister
(copper shell and insert) will be formulated in 2005. The criteria will stipulate limits for defects
in different fabrication processes and the effects these defects have on the canister’s properties.
Furthermore, the ability of the testing methods to detect these defects will be quantified.
The aim of component fabrication is, by 2006, to fabricate a sufficient number of canister components
using a reference method under serial forms, and confirm that these components satisfy
stipulated quality requirements, in order to verify that the designs and fabrication methods are
reliable. This goal will be achieved by trial fabrication at a supplier and progressive development
of the fabrication methods based on evaluation of achieved quality.
Development of other fabrication methods will continue. Qualification of these methods is
intended to be done as late as possible to retain flexibility and enable technical advances to be
adopted.
A3.3.3 Fabrication
Fabrication of the components for the canisters will be done at different suppliers, both in
Sweden and abroad. However, SKB needs to have strict control over the canister components
that are delivered to the encapsulation plant. Final adjustment and assembly of the canister components
is therefore planned to take place under SKB’s auspices, possibly in cooperation with
SKB’s Finnish counterpart Posiva. A factory for these purpose can be compared to an advanced
engineering works. No fuel assemblies will ever be present in the plant. As noted previously, the
siting work for canister fabrication has not begun.
A3.4 Safety assessment
The planning for safety assessments during the site investigation phase is described in its
entirety in section A2.3.3. The permit application for the encapsulation plant will be based
on the safety assessment SR-Can. The recently published interim report from the work with
SR-Can describes completed method development, as well as plans to answer the method
questions that remain before a final report can be published on the project.
The goal of SR-Can is to show that canisters that have been sealed and tested with the
technology that is developed, selected and demonstrated prior to the permit application can
ensure a repository that satisfies the safety requirements, given the repository environment
offered by the candidate sites. Experimental data from the demonstration phase of the work in
particular will therefore comprise an important part of the input data for SR-Can.
Site data from the initial site investigations will be used in SR-Can. The links between the
different steps in the investigations, design of the deep repository and the background material
for SR-Can are shown in Figure 10.
382 RD&D-Programme 2004