RD&D-Programme 2004 - SKB

15.1.2 Geometry
The deep repository will contain fuel of various types and geometries.
Conclusions in RD&D 2001 and its review
SKB announced its participation in the EU project SFS (Spent fuel stability under repository
conditions), which was started for the purpose of conducting research on detailed geometry,
crack distribution and fission product distribution, and their evolution with time.
No direct viewpoints were offered on this by the authorities.
Newfound knowledge since RD&D 2001
The SFS project is not yet concluded. A final evaluation of the project and a report on the results
will not be available until the end of 2004. SKB has had an independent expert conduct a critical
review of these issues /15-3/. The conclusions are that there is no reason at present to assume
that the geometry of the fuel will undergo decisive changes over long periods of time.
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.
15.1.3 Radiation intensity
The radiation intensity is dependent on the radioactivity, i.e. the inventory of radionuclides and
the geometry of the fuel. Both of these are well-known, and the dose rate can be calculated with
sufficient accuracy for the needs of the safety assessment.
Conclusions in RD&D 2001 and its review
There was no research programme on this process in RD&D 2001, and no direct viewpoints on
this 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.
15.1.4 Temperature
The critical interface in the canister is the transition between the cast iron insert and the copper
shell. The copper’s emissivity is of crucial importance.
Conclusions in RD&D 2001 and its review
Heat transfer between the canister surfaces, especially the thermal emittance of the copper,
needs to be determined so that better calculations of the temperature distribution inside the
canister can be performed.
SKI would like to see a more detailed description of the studies of emissivity and temperature
evolution in the canister, but is positive to the fact that SKB is planning to use such studies in
order to develop design requirements for the canister surfaces.
164 RD&D-Programme 2004