Exploratory what-if analysis of some debated canister failure modes in the review of a licence application for the construction and operation of a spent nuclear fuel repository in Sweden
<p>Regulatory review of the licence application for construction and operation of a spent fuel repository at the Forsmark site in Sweden involves detailed assessment of both expected and hypothetical failure modes of the copper canister. The copper canister, which is supported by the bentonite...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-08-01
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| Series: | Advances in Geosciences |
| Online Access: | https://www.adv-geosci.net/49/67/2019/adgeo-49-67-2019.pdf |
| Summary: | <p>Regulatory review of the licence application for construction and
operation of a spent fuel repository at the Forsmark site in Sweden involves
detailed assessment of both expected and hypothetical failure modes of the
copper canister. The copper canister, which is supported by the bentonite
buffer and the surrounding crystalline rock in the KBS-3 concept, is
expected to provide complete containment of radioactive elements for very
long timescales. Detailed assessment shows that there is a small probability
on such timescales of canister failure due to corrosion following loss of
buffer as well as mechanical failure due to large earthquakes. During the
regulatory review process, it was proposed that canisters might also fail
due to: (i) corrosion in anoxic oxygen gas free water, (ii) pitting corrosion,
(iii) stress corrosion cracking, (iv) creep brittle failure, (v) hydrogen
embrittlement. We here provisionally accept a number of alternative
assumptions related to these processes as a basis for what-if analysis of
their implications. The focus is not to determine the merit or to estimate
probability of these cases, but rather to explore their potential
significance in the context of the available knowledge about the repository
environment. Simplified estimates are made of the consequences in terms of
number and timing of canister failures as well as radiological impact. It is
judged that poor creep ductility of copper would have larger potential
consequences compared to localised corrosion phenomena. Potential corrosion
failures are expected to be associated with the small fraction of deposition
holes that are most extensively exposed to corrodants.</p> |
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| ISSN: | 1680-7340 1680-7359 |