Ageing management of nuclear power plants as built structures focuses on the structures that are safety-related. These structures are made of solid reinforced concrete, with the structural component dimensions not being governed by the effects of actions occurring involved in normal operation, but rather in terms of the require­ments of protective effects against radiation and designed to cope with internal events, such as coolant loss, or rare external events, such as earthquakes, explosion pressure waves and aircraft impact.

Design and Construction of Nuclear Power Plants. First Edition.

Rudiger Meiswinkel, Julian Meyer, Jurgen Schnell.

© 2013 Ernst & Sohn GmbH & Co. KG. Published 2013 by Ernst & Sohn GmbH & Co. KG.

Many of the factors that have to be considered as part of ageing management occur in conventional structures just as much as they do in nuclear power plants, so that the knowhow and experience of harmful mechanisms in conventional structures can be applied directly. What is peculiar to nuclear power plants are the radioactivity and increased ambient temperatures which can cause materials to decay if exposed to them.

KTA 1403 [106] divides structural systems into structures/substructures, construction systems and structural components. Structures/substructures are complete buildings or larger sections of buildings to be identified via the power plant coding system (see Section 4.2.1). Construction systems are groups of structural components that perform a common function, such as steel platforms, sealing against water pressure and structural fire protection elements. Construction systems consist of structural compo­nents such as anchor plates, fire doors and fire stop valves.

Structures/substructures, construction systems and structural components need to be classified in accordance with their safety requirements. For ageing management purposes, those that need to be considered are those that are safety-related.

Building structures and buildings need to be checked regularly to see if they have departed from nominal in any way, such as faults due to subsoil settlement or cracking, corrosion or plastics losing their seal and protective functions. Conducted as preventive maintenance, these inspections can be used to detect ageing mechanisms in good time and take appropriate follow-up measures to prevent serious damage.