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Recent publications

Workreport 2018-26



Thermal Dimensioning fot the Olkiluoto Repository - 2018 Update


Ikonen, K., Kuutti, J., Raiko, H.



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This report presents the updated analyses for thermal dimensioning of the KBS-3V type spent nuclear fuel repository in Olkiluoto. This report concerns only the thermal dimensioning of the repository and does not take into account the restrictions caused by the rock mechanical stresses.

The maximum temperature on the canister-bentonite interface is limited to the design temperature of +100°C. For the reasons presented in this report, due to uncertainties in thermal analysis parameters the nominal calculated maximum canister temperature is set to 95°C having thus a safety margin of 5°C. The maximum temperature can be con-trolled by adjusting the space between adjacent canisters, or adjacent tunnels, or the decay heat power of the canisters, for example.

For the Olkiluoto repository, the dimensioning was made assuming the canisters to be in rectangular panels of 900 canisters of BWR, VVER or EPR spent fuel. The analyses were performed for each canister types using the design decay heat power at installa-tion. The analyses resulted in the canister spacing of 8.88, 7.41, and 10.52 m, for BWR, VVER and EPR canister panels, respectively, when the tunnel spacing was 25 m. Also tunnel spaces 30, 35 and 40 m were analysed for optimizing purpose. In addition, by varying the principal initial parameters, a large number of sensitivity analyses were made.


Spent nuclear fuel, repository, decay heat, thermal dimensioning


WR 2018-26_web (pdf) (8.4 MB)


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