Workreport 2018-26



Thermal Dimensioning fot the Olkiluoto Repository - 2018 Update


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



Page count:



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)


Share article:
This website stores cookies on your computer. These cookies are used to improve our website and provide more personalised services to you.


To make this site work properly, we sometimes place small data files called cookies on your device. Most big websites do this too.

1. What are cookies?

A cookie is a small text file that a website saves on your computer or mobile device when you visit the site. It enables the website to remember your actions and preferences (such as login, language, font size and other display preferences) over a period of time, so you don’t have to keep re-entering them whenever you come back to the site or browse from one page to another.

2. How do we use cookies?

A number of our pages use cookies to remember your actions and preferences (such as login, language, font size and other display preferences.)

Also, some videos embedded in our pages use a cookie to anonymously gather statistics on how you got there and what videos you visited.

Enabling these cookies is not strictly necessary for the website to work but it will provide you with a better browsing experience. You can delete or block these cookies, but if you do that some features of this site may not work as intended.

The cookie-related information is not used to identify you personally and the pattern data is fully under our control. These cookies are not used for any purpose other than those described here.

3. How to control cookies

You can control and/or delete cookies as you wish – for details, see You can delete all cookies that are already on your computer and you can set most browsers to prevent them from being placed. If you do this, however, you may have to manually adjust some preferences every time you visit a site and some services and functionalities may not work.