Reasonable expectation.

CFR · 2024-01-01 · US · Title 10

(1) Requires less than absolute proof because absolute proof is impossible to attain for disposal due to the uncertainty of projecting long-term performance; (2) Accounts for the inherently greater uncertainties in making long-term projections of the performance of the Yucca Mountain disposal system; (3) Does not exclude important parameters from assessments and analyses simply because they are difficult to precisely quantify to a high degree of confidence; and (4) Focuses performance assessments and analyses on the full range of defensible and reasonable parameter distributions rather than only upon extreme physical situations and parameter values.

official document · source cfr-2024 · id 10:§ 63.304