Life management in Russian nuclear power plants

The purpose of a systematic NPP life management is to allow the lifetime of plant components to be planned, and to indicate when a component has reached the end of its effective lifetime before it fails. Another important function of such a strategy is to increase the availability of power plants and to enable implementation of a targeted maintenance strategy in terms of its safety, economic and technical effect. Ageing is a process where physical and mechanical properties of materials and equipment change in the course of time. The process could be single mechanism or a combination of several ageing mechanisms. All materials installed at NPP are more or less subject to degradation due to ageing. The ageing can cause functional degradation of NPP elements and ultimately influence their safety. Therefore, it is vital to understand and control ageing of all elements that can influence safety. Ageing process of elements must be controlled in order to provide required safety margin during lifetime including any prolongation of the term