Databank

Workreport 2007-29

Back

Name:

Far-Field Thermal-Mechanical Response of One- and Two-Storey Repositories in Olkiluoto

Writer:

Ikonen, K.

Language:

English

Page count:

35

Summary:

This report contains results from far-field temperature and deformation analysis of the spent nuclear fuel repository in Olkiluoto. The objective of the analyses was to determine dimensions of the tensile stressed bedrock above the repository near the ground surface. Tensile stresses may open fractures in rock mass and ground water flow may become faster, if suitable pressure differences exist and further, potential for radio-nuclide transport from leaking canisters becomes higher to upward direction, towards biosphere. In considering stress state far from the rectangular repository the most essential parameters are the length, width and depth of the repository and the total decay heat density. Other details, like vertical or horizontal orientation of canisters is of less importance when considering situation far from the repository. The absolute value of the stress locally in the bedrock depends remarkably on the existing compressive natural in-situ stresses, which have different values in various orientations. The estimated Olkiluoto in-situ stresses based on the site characterization investigations have been taken into account.

The depth in tensioned volume extends in the one-storey repository to the depth of 94…107 m after about 300 years and in the two-storey repository to the depth of 129…146 m. The maximum tensile strain on the ground surface is about 0.00024 after about 600 years. Two-dimensional plane strain analyses gave conservative results when compared with more realistic three-dimensional analyses. When assuming the decreased deformation modulus for the rock mass due to the tensile cracking very conservatively the maximum depth of the tensile stressed rock is increased at most 10%. Ground uplift reaches its maximum of 6.9 cm about 1 230 years in the one-storey repository and 12.6 cm in the two-storey repository after about 1 400 years.

Keywords:

TM analyses, far-field stresses in repository for spent nuclear fuel, repository, Olkiluoto, decay heat

File(s):

Far-Field Thermal-Mechanical Response of One- and Two-Storey Repositories in Olkiluoto (pdf) (647.7 KB)


Back


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

Cookies

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 aboutcookies.org. 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.

Close