"Active maintenance" means any significant activity needed during the period of control after closure of the disposal area to ensure reasonable protection against inadvertent intruders and the migration of radionuclides, including activities such as the pumping and treatment of water from a disposal unit or replacement of the cover of a disposal unit. The term does not include continuing custodial activities such as the repair of fencing, repair or replacement of equipment for detecting radiation, revegetation, minor additions to the depth of soil covering a disposal unit and general upkeep such as mowing grass.
Nev. Admin. Code § 459.8005
NRS 459.201