Standby.
Standby. Standby means the period of time that an impoundment is not accepting uranium byproduct material or tailings but has not yet entered final closure.
Source
40 CFR § 61.251
Scoping language
As used in this subpart, all terms not defined here have the meaning given them in the Clean Air Act or 40 CFR part 61, subpart A. The following terms shall have the following specific meanings: