This national standard establishes the requirements for evaluating the occurrence and movement of radionuclides in the subsurface resulting from abnormal radionuclide releases at commercial nuclear power plants. This standard applies to abnormal radionuclide releases that affect groundwater@ water supplies derived from groundwater@ and surface waters affected by subsurface transport@ including exposure pathways across the groundwater?C surface-water transition zone. This standard does not apply to the following: subsurface occurrence and movement of nonradioactive materials@ other than as indicators of subsurface radionuclide occurrence and movement in soil and groundwater; surface occurrence and movement of radionuclides@ except to the extent that surface radionuclide occurrence and movement might affect@ or be affected by@ on-site subsurface radionuclide occurrence and movement (e.g.@ a surface release that subsequently infiltrates and affects groundwater@ a subsurface release that affects surface water@ including exposure pathways across the groundwater?Csurface-water transition zone); corrective action@ which might be required as the result of a subsurface radionuclide release; dose calculations to demonstrate compliance with any regulatory requirement.