This report summarises the responses provided by the member organisations of the Working Group on Integrity and Ageing of Components and Structures (WGIAGE) of the Committee on the Safety of Nuclear Installations (CSNI) to a questionnaire on buried and underground tanks and piping (BTP) at commercial nuclear power plants. The questionnaire is comprised of twenty questions that address: operating experience; applicable codes and standards; the relevant regulatory framework; ongoing regulatory actions; the nuclear industry’s responsibilities, plans, and actions within each country; and the technical and regulatory challenges. The principal objectives of this questionnaire are to gauge international interest in developing a database on BTP operating experience, identify information that could be contained in the database, share information on activities related to BTP, and identify possible areas for future collaboration. Responses were provided from representatives from seven countries as well as the Joint Research Centre (JRC) of the European Commission (EC).