RD&D-Programme 2004 - SKB

Nondestructive testing methods such as radiographic and ultrasonic inspection will be developed
so they can detect both volumetric and other defects in the weld. The results of this work
will be regularly compared with metallurgical investigations to obtain defect descriptions for the
FSW process. The information will be collected in a catalogue of physical properties of FSW
welds.
6.4 Nondestructive testing of the sealing weld
The work on nondestructive testing at the Canister Laboratory is focused on testing of the
canister’s sealing weld. During 2003 the scope of the work has been broadened from testing of
EBW welds only to testing of FSW welds as well.
The work being done on nondestructive testing at the Canister Laboratory can be described as
follows:
1. Development of existing methods and trials of new methods for nondestructive testing of the
sealing weld.
2. Application of nondestructive testing according to established procedures for evaluation of
welding trials.
3. Verification of the reliability of the testing methods.
The methods used at the Canister Laboratory are digital radiographic testing (RT), ultrasonic
testing using the phased array technique (UT), and eddy current testing (ET).
Conclusions in RD&D 2001 and its review
Development of methods and equipment for NDT of canisters sealed by EBW is under way at
the Canister Laboratory. The project is planned to be concluded in early 2004. The development
work is now finished with the exception of eddy current testing, which is expected to be
implemented gradually during 2004.
In addition, it is noted from RD&D 2001 that a project was to be started for development of
methods and equipment for NDT of canisters sealed by FSW. The development work is under
way and is planned to be concluded during 2004.
Furthermore, it was observed that a research project has been under way at Uppsala University
for the past five years concerned with ultrasonic testing of EBW-welded copper canisters. The
results obtained in the project will be used at the Copper Laboratory. Implementation of signal
processing algorithms for ultrasonic testing is currently under way at the Canister Laboratory.
A development project was initiated during 2000 in which Uppsala University, the University
of Magdeburg and the Canister Laboratory are jointly developing the technology for detection
of near-surface discontinuities in copper by eddy current testing. The development work has
continued during the period, and the results are being implemented at the Canister Laboratory.
SKI has pointed out the lack of coherent documentation of results and experience obtained
from nondestructive testing. SKB has presented such results in Project Memorandum TI-03-04,
which was published in May 2003. The report covers the work with nondestructive testing of
the canister through 2002. This memorandum has also been published as an SKB report /6-6/.
Newfound knowledge since RD&D 2001
A milestone that has been reached is that testing procedures have been established for radiographic
and ultrasonic testing of EBW sealing welds. In order to investigate the detection
capability of the NDT methods, a study has been conducted where some 40 indications from
radiographic and ultrasonic testing have been studied with respect to the actual character of the
82 RD&D-Programme 2004