13-15 Oct 2014

EPRI, Charlotte, USA

Ageing Management of Buried and Underground Piping and Tanks for NPPs


Buried and underground piping and tanks are key components of nuclear power plants (NPPs) but due to their location are difficult to inspect and assess. Leaks from buried piping can and have resulted in impacts on NPP safety related systems, and have caused releases of radiation (typically tritium) or conventional contaminants (typically oil or fuel) to the natural environment. Such releases can be a cause of public concern regarding overall NPP operation and safety, and thus need to be minimized to ensure public confidence in nuclear technology. Repairs to buried piping systems typically are more difficult to implement that for above ground piping, as specific break locations are more difficult to locate, accessibility to break locations typically requires careful excavation (to not make a small problem catastrophically worse), and isolation of breaks is often more difficult or more impactful to plant operations. The science and technology regarding buried piping ageing management has developed over time as the world NPP fleet has aged. Numerous utility and industry groups (e.g. INPO, WANO, EPRI, NEI, NACE International etc.), have investigated or performed research into the topic. Risk informed approaches have been developed in some instances. Utilities and regulators have needed to address the state of older buried piping systems in the context of plant relicensing and life extensions. Some utilities have opted for design changes to change underground systems to above ground systems to facilitate inspections. There is significant operating experience outside of nuclear, notably in oil and gas, and in municipal water / sewage applications.

The purpose of the meeting is to share information on national experiences on the subject matter and to incorporate them into a future IAEA Nuclear Energy Series publication. The following specific topics in the context of buried and underground piping and tanks in NPPs will be discussed during the meeting:

  • national activities and practices associated with risk ranking, inspection, mitigation, and repair;
  • national codes, standards, and regulations;
  • national operating experience and events within the nuclear sector; and
  • research and development activities.

Working Documents


IAEA Scientific Secretary

  • John H. Moore, Nuclear Power Engineer
    Nuclear Power Engineering Section
    Division of Nuclear Power, IAEA Department of Nuclear Energy

Please contact NENP Engineering Section - Contact Point if you have any questions.