U.S. Nuclear Regulatory Commission
Question 133: 10 CFR 20.1101 (b) requires licensees to use, to the extent "practicable," procedures and engineering controls based upon sound radiation protection principles to achieve doses that are ALARA. The ALARA concept emphasizes dose-reduction techniques that are reasonable considering costs. However, "practicable" may imply something that has been proposed and seems feasible but has not been actually tested in use. "Practical" is more consistent with the ALARA concept because "practical" implies "sensible", "involving good judgement" and "proven success in meeting the demands made by actual living or use." In making decisions about ALARA procedures and engineering controls, will licensees be permitted to interpret "practicable" as "practical"?
Answer: In the context of this regulation, the word "practicable does not have the connotations attributed to it in the question. 10 CFR 20.1003 states that "ALARA . . . means making every reasonable effort to maintain exposures to radiation as far below the dose limits in this part as is practical . . . " emphasis added). The discussion of 10 CFR 20.1101 (b) in the preamble to revised Part 20 (56 FR 23367) includes the following statement: "Compliance with this requirement [10 CFR 20.1101 (b)] will be judged on whether the licensee has incorporated measures to track and, if necessary, to reduce exposures and not whether exposures and doses represent an absolute minimum or whether the licensee has used all possible methods to reduce exposures." Thus the use of the word "practicable" in 10 CFR 20.1101 (b) does not imply procedures and engineering controls that are unproven.
(Reference: 10 CFR 20.1101)