RD&D-Programme 2004 - SKB

Spacer plate
Defect
A
Defect
B
Channel plate
Figure 5-14. Cut area 270 centimetres from bottom of insert I25.
Lids and bottoms of copper
No new knowledge has been forthcoming.
Copper tubes
A reference ring with artificial defects has been developed. It has been used to ensure that the
automatic ultrasonic systems that have been used are able to detect certain types of defects. The
defects in the reference ring are grooves at different depths. The method can detect faults situated
radially in the cylinder, but cannot determine their size. Axial defects can also be detected
and size-determined to some extent. Experience from the Canister Laboratory shows that testing
of copper tubes can be developed and improved, from the viewpoint of both detection and
evaluation.
Steel lids
No new knowledge has been forthcoming.
Miscellaneous
Tests have been conducted to investigate the possibility of determining the grain size of
the copper material with ultrasound. The method uses sound attenuation as a measurement
parameter. The results show that the method has potential for providing the desired data.
Programme
Plans call for experience accumulation and method development to take place during the period
2004–2005.
Preliminary NDT procedures are planned to be established during 2005. As a part of this work,
suitable reference bodies will be developed.
Continued experience accumulation and evaluation of reliability is planned during the period
2006–2007. This work will be pursued in close cooperation with the Canister Laboratory.
Further investigations are planned to determine material parameters by means of ultrasound
in both copper and nodular iron. In copper the grain size is of interest, and in nodular iron the
nodularity of the graphite.
The occurrence of different defect types in nodular iron is being investigated in the project
concerning probabilistic analysis of the strength of the insert, see section 5.3.1. These will be
characterized from an NDT perspective and catalogued.
Studies of possible defect types that can arise during the different fabrication processes in
copper and nodular iron are planned.
62 RD&D-Programme 2004