United States Nuclear Regulatory Commission - Protecting People and the Environment

T7  Evaluating Residual Radioactivity in the Subsurface at Operating and Decommissioning Nuclear Power Plants

The session’s purpose is to examine assessments of non-routine and unintended releases of radionuclides from nuclear power plants to the subsurface which includes soil and ground-water systems.  These assessments involve characterization, monitoring, modeling and corrective actions.  Examples of abnormal releases to the subsurface may include leakage from condensate tanks, spent fuel pools, and buried pipelines.  The session focus will be on evaluating residual radioactivity1 in the subsurface related to the operations and decommissioning of nuclear power plants (NPP).  For 10 CFR Part 50 licensees, adequate implementation of the Nuclear Energy Institute’s (NEI) Groundwater Protection Initiative (GPI), NEI-07-07 provides one acceptable method of implementing the Decommissioning Planning Rule requirements in 10 CFR 20.1406 and 10 CFR 20.1501.  NRC’s Inspection Procedures (IP 71124.06) provides guidance to NRC for verifying that the licensee is continuing to implement the NEI/industry ground-water protection initiative (GPI).  Also IP 88045 provides guidance to NRC inspectors that licensees discuss any new contamination identified in the environment or subsurface of the facility or surrounding environment, and verify that the licensee, to the extent practical, conducts operations to minimize the introduction of residual radioactivity into the site, including the subsurface, in accordance with 10 CFR 20.1406 (c).

The technical challenge is to identify the presence and behavior of residual radioactivity and what constitutes an effective monitoring and assessment program during the period of compliance.  The session will include presentations by the Electric Power Research Institute (EPRI); the French Nuclear Safety Authority (ASN); DOE’s Lawrence Berkeley National Laboratory (LBNL); and NMSS staff on regulatory requirements and guidance, and monitoring and modeling programs to evaluate residual radioactivity at NPP sites.  The objective is to bring together experts from regulatory inspection authorities, industry, and foreign entities who are actively studying site residual radioactivity in soil and ground water.  Information from past and ongoing studies including new technologies will be showcased to help inform licensee options and decisions.  The lessons learned from these activities will be discussed, particularly information on the radionuclide source terms and release pathways, site characterization, adequacy of radiological surveys, and various corrective action programs that may include remediation of subsurface soil and ground-water systems.

1 Residual radioactivity means radioactivity in structures, materials, soils, groundwater, and other media at a site resulting from activities under the licensee's control (from 10 CFR20.1003).


  • Jack Parrott, Senior Project Manager, Division of Advanced Reactors and Rulemaking, Division of Decommissioning, Uranium Recovery and Waste Programs, NMSS/NRC tel: 301-415-6634, e-mail: Jack.Parrott@nrc.gov



  • Ralph Andersen, Senior Director for Radiation Safety & Environmental Protection, Nuclear Energy Institute


  • William Ford, NRR/NRC
  • Michael Wentzel, NRR/NRC
  • Steve Garry, NRR/NRC
  • Nebiyu Tiruneh, NRO/NRC
  • Boby Abu-Eid, NMSS/NRC
  • Marlayna Vaaler, NMSS/NRC
  • Pamela Longmire, NMSS/NRC
  • Hans Arlt, NMSS/NRC
  • Ralph Cady, RES/NRC
  • Shannon Thompson, RES/NRC
  • Katie Tapp, RES/NRC
  • Anthony Delamonte, NRC foreign assignee from French ASN


  • Tom Nicholson, Senior Level Advisor, Division of Risk Analysis, RES/NRC tel: 301 251 7498, e-mail: Thomas.Nicholson@nrc.gov
  • David Aird, Project Manager, Division of Risk Analysis, RES/NRC tel: 301-251-7926, e-mail: David.Aird@nrc.gov
Page Last Reviewed/Updated Friday, June 05, 2015