Concrete Degradation Modeling in the Evaluation of Entombment as a Decommission Option.
Concrete Degradation Modeling in the Evaluation of
Entombment as a Decommission Option.
Snyder, K. A.; Philip, J.
Nuclear and Hazardous Waste Management International
Conference: Spectrum 2002. Proceedings. August 4-8,
2002, Reno, NV, 2002.
concretes; degradation; evaluation; entombment;
monitoring; service life
For entombment to be a viable option for the
decommissioning of nuclear structures, the effectiveness
of available engineered barriers must be assured.
Barrier performance must be estimated with the aid of
computer models that can accurately predict the response
of the barrier to foreseeable physical and chemical
conditions. For concrete barriers, virtually all
degradation mechanisms are controlled by the transport
of water and ionic species within the pore space. These,
in turn, are controlled by the appropriate transport
coefficients. For sound concrete, the transport
coefficients are sufficiently small enough that
isolation is expected. It is the presence of cracks
within the concrete that compromises the barrier by
increasing the transport coefficients dramatically.
Therefore, additional efforts to characterize the
performance of concrete barriers must focus on
quantifying the existing cracks and flaws within the
concrete. This characterization would include sampling
(when possible), non-destructive techniques, and
computer modeling. All of these are incorporated into a
coherent monitoring plan.