RD&D-Programme 2004 - SKB

Newfound knowledge since RD&D 2001
No new knowledge has been forthcoming.
Programme
The investigation of iron corrosion in initially oxygen-free water under gamma radiation is
still under way and will be concluded during 2005, see also section 16.2.8.
15.2.11 Metal corrosion
This section concerns corrosion of cladding tubes and metal parts in the fuel.
Conclusions in RD&D 2001 and its review
No research programme for this area was included in RD&D 2001, and no direct viewpoints
were offered in the review.
Newfound knowledge since RD&D 2001
No new knowledge has been forthcoming.
Programme
The field is judged today not to require any further research, development or demonstration.
New developments are being monitored and will be acted on when appropriate.
15.2.12 Fuel dissolution
Conclusions in RD&D 2001 and its review
Both SKI and Kasam state that the fuel programme has shown positive progress in recent years
and has largely been conducted in a manner that is appropriate in relation to the needs of the
safety assessment. The results reported by SKB so far provide a necessary basis for the development
of a credible and realistic fuel model that allows for a significant barrier function. In SKI’s
opinion, more experiments and better models that explain the results of the experiments are
needed. SKB should study how fuel dissolution is affected by different degrees of exposure (to
groundwater), and by canister and buffer damage. SKB should ask itself whether it is possible
to take credit for the hydrogen gas from corrosion for very long times in the safety assessment.
SKI would like to see a discussion of the influence of other hydrogeochemical parameters
(salinity, pH, carbonate concentration etc) and whether they are adequately covered by the
experimental programme. SKI welcomes the fact that SKB has taken the initiative to obtain
better experimental data for instant release of radionuclides. Kasam judges that the research
programme on fuel dissolution, which was of a generally orientational nature to begin with,
needs to be focused on the conditions that will exist inside the canister according to the results
of analyses.
Newfound knowledge since RD&D 2001
The results described here come from SKB’s own research programme and from our participation
in two projects within the EU’s Fifth Framework Programme (SFS and InCan).
Fuel leaching under different redox conditions
The redox condition is the most important factor for fuel dissolution, and special attention has
been devoted to it in recent years. The measurements of the redox potential have given us a
better understanding of the expression “anoxic conditions” and the difficulties associated with
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