Life span of pressurized water reactors

The important place that PWR nuclear power stations have taken in the EDF's overall production facilities justifies a special effort being made to assess their working life. It would appear that a PWR needs better technical and economic conditions during its lifetime than the old thermal stations. The EDF ''lifetime project'' comprises a 4 year work schedule. First there will be a full inventory of the available data to assess the ageing process of the sensitive material in a power station and follow its evolution in order to forecast or correct it. The sensitive materials are those for which the difficulty and cost of reprocessing or replacement exclude these operations from the standard maintenance programmes. An initial analysis of the ways in which these materials can be damaged leads to the conclusion that the major causes of ageing, which are a priori brittleness in the reactor vessels due to irradiation and metal fatigue in the main boiler components, will not limit the life of these sensitive materials, perhaps only in the very long term. It cannot be denied that overcoming certain damage due to material ageing or corrosion poses difficult maintenance problems which it is important to the able to forecast and measure. If this essential effort is made, the life span of a PWR could be very long