As a consequence, there is considerable uncertainty regarding the resistance to potential internal and external impacts. This relates above all to the withstanding of loads due to external burden or impact, such as loads due to wind, snow, or earthquake, for example. There is broad agreement that the risk of a partial or total collapse during the initially projected design lifetime of the sarcophagus of about 30 years is not negligible if no countermeasures are taken. Even in the worst case of a complete collapse, widespread effects are not to be expected. Nevertheless, the stabilization of the sarcophagus is an issue of high priority.
Water entering the sarcophagus is another significant safety issue.
The presence of water stimulates the disintegration of fuel masses into dust and degradation of building structures by corrosion, and can increase the reactivity of fuel masses. Regarding the risk of groundwater contamination, the existence of water in the sarcophagus bears some risk in the long term. However, this risk is assumed to be much smaller than that from contact of water with the radioactive material buried in the ground outside the sarcophagus. Possibilities of recriticality have been widely investigated. It has been found that the sarcophagus is currently safe from a criticality point of view.