The design life of a nuclear power plant (NPP) does not necessarily equate with the physical or technological end of life (EOL) in terms of its ability to fulfill safety and electricity production requirements. Systems, structures and components (SSCs) in a NPP is subjected to a variety of chemical, mechanical and physical conditions during operation. Stressors lead changes with time in the SSC materials, which are caused and driven by the effects of corrosion, varying loads, flow conditions, temperature and neutron irradiation. It is quite feasible that many NPPs will be able to operate for times in excess of their nominal design lives, provided appropriate and proven ageing management actions are implemented in a timely manner.

To launch a PLiM programme the utility or plant should establish a PLiM group at the plant to develop a detailed plan specific to the utility organization. Then a PLiM pilot project is typically undertaken. The scope of the PLiM pilot project can vary but should include PLiM planning and some pilot ageing assessments, so that the utility PLiM team can gain significant level of experience and learning that will enable them to plan, perform and implement the full comprehensive PLiM programme. Also, procedures developed early in the PLiM pilot project should be updated with the experience gained in application from the pilot ageing assessments.

Those systems, structures and components that are to be included in a PLiM programme are usually identified by a systematic screening process, which prioritizes the systems based on their importance to achievement of plant goals, such as nuclear safety, environmental safety, and production reliability. In addition, structures and components whose failure would result in a major replacement cost or in a significant loss of production capability are also typically considered.

Effective plant practices in monitoring, surveillance, maintenance, and operations are the primary means of managing ageing. From general experience with HWR PLiM programmes, it can usually be expected that the PLiM assessment programme will lead to modifications and enhancements, but not likely replacements, of the existing plant programmes that address ageing. However, a successful PLiM programme will provide assurance that current plant programmes are modified to be effective in managing ageing. This requires a structured and managed approach to the implementation process. The overall objective is to optimize plant programmes for ageing management, both for the remaining design life period and for the plant extended operation to come.

Long term operation can be considered as other of a fully integrated PLiM programme. LTO requires careful planning and scoping. The HWR utility would normally initiate a detailed LTO study at their particular plant (with an objective to extend plant operation another 20 to 30 years) many years before the end of design life. In fact, ideally, a station should implement this from initial startup for optimal effectiveness and cost, and to maximize asset value. The end product of this study is a business case that compares the costs of refurbishing their NPP with costs of alternate means of generation.

Atomic Energy Commission is working in a programme of life management of Embalse nuclear power plant, with view to their safe operation and to be able to for long term operation. (LTO). This programme is based on the studies of some specifics selected critical components. In some of them is carried out an evaluation of their condition assessment (CA), like it is the case of the system of feeding water and of the moderator’s system. Also, this is carrying out in the bombs of the control of pressure and inventory system.

Within this programme is also carried out the life evaluation (LE) the steam generators, the moderator’s exchanges, the system of feeding water bombs system and the feeders. All this is related with a detailed study of the effects of erosion corrosion in the secondary system for which a computational programme has been elaborated that it has been corroborated with obtained data obtained from the power plant. The programme includes also pressure tube and the calandria tube.

For the realization of these activities there is being integrated a group of professionals that they can dominate in a future with ease the topic of life management of facilities. This is a multidisciplinary group that will allow carrying out the task and used typical procedure for CANDU reactors, where the history of each component is continued during the operation as well as possible deviations in its construction and the influence on the degradation mechanism.