40 CFR 194.44 - Engineered barriers.
(a) Disposal systems shall incorporate engineered barrier(s) designed to prevent or substantially delay the movement of water or radionuclides toward the accessible environment.
(b) In selecting any engineered barrier(s) for the disposal system, the Department shall evaluate the benefit and detriment of engineered barrier alternatives, including but not limited to: Cementation, shredding, supercompaction, incineration, vitrification, improved waste canisters, grout and bentonite backfill, melting of metals, alternative configurations of waste placements in the disposal system, and alternative disposal system dimensions. The results of this evaluation shall be included in any compliance application and shall be used to justify the selection and rejection of each engineered barrier evaluated.
(1) In conducting the evaluation of engineered barrier alternatives, the following shall be considered, to the extent practicable:
(i) The ability of the engineered barrier to prevent or substantially delay the movement of water or waste toward the accessible environment;
(ii) The impact on worker exposure to radiation both during and after incorporation of engineered barriers;
(iii) The increased ease or difficulty of removing the waste from the disposal system;
(iv) The increased or reduced risk of transporting the waste to the disposal system;
(v) The increased or reduced uncertainty in compliance assessment;
(vi) Public comments requesting specific engineered barriers;
(vii) The increased or reduced total system costs;
(viii) The impact, if any, on other waste disposal programs from the incorporation of engineered barriers (e.g., the extent to which the incorporation of engineered barriers affects the volume of waste);
(ix) The effects on mitigating the consequences of human intrusion.
(2) If, after consideration of one or more of the factors in paragraph (c)(1) of this section, the Department concludes that an engineered barrier considered within the scope of the evaluation should be rejected without evaluating the remaining factors in paragraph (c)(1) of this section, then any compliance application shall provide a justification for this rejection explaining why the evaluation of the remaining factors would not alter the conclusion.
(d) In considering the ability of engineered barriers to prevent or substantially delay the movement of water or radionuclides toward the accessible environment, the benefit and detriment of engineered barriers for existing waste already packaged, existing waste not yet packaged, existing waste in need of re-packaging, and to-be-generated waste shall be considered separately and described.
(e) The evaluation described in paragraphs (b), (c) and (d) of this section shall consider engineered barriers alone and in combination.