Engineered Barriers

Assurance requirements were included in the disposal regulations to compensate in a qualitative manner for the inherent uncertainties in projecting the behavior of natural and engineered components of the repository for many thousands of years (50 FR 38072). Section 194.44 is one of the assurance requirements in the Compliance Criteria. Section 194.44 implements the assurance requirement at Section 191.14(d) to incorporate one or more engineered barriers at radioactive waste disposal facilities. The disposal regulations define a barrier as “any material or structure that prevents or substantially delays movement of water or radionuclides toward the accessible environment” (Section 191.12(d)). Section 194.44 requires that DOE conduct a study of available options for engineered barriers at the WIPP and submit this study and evidence of its use with the compliance application. Consistent with the containment requirement at Section 191.13, DOE must analyze the performance of the complete disposal system, and any engineered barrier(s) that DOE ultimately implements at the WIPP must be considered in this analysis and EPA’s subsequent evaluation (see Response to Comments Document for 40 CFR Part 194, p. 16-11). This CARD combines the discussion of requirements Section 194.44(c) through (e) because they pertain to the same analysis by DOE.