The lifetime of PWR nuclear power plants

The significance of the role played by PWR nuclear power plants in the production resources of Electricite de France (EDF) justifies making a special effort to assess their lifetime. The lifetime of PWRs seems to benefit from technical and economic conditions which are more favourable than those of earlier thermal equipment. EDF's 'lifetime project', which was started at the end of 1985, involves a four year work programme. First of all, a complete list is to be made of the data available for predicting the ageing of sensitive materials in a power plant and for monitoring changes in them so as to prevent or remedy ageing. These sensitive materials are those where the difficulties and costs involved in repair or replacement are such that they cannot be included in the normal maintenance programmes. An initial analysis of the types of damage to these materials gives reason to believe that the major causes of ageing, which are essentially embrittlement due to irradiation of the tanks and fatigue of the main components of the boilers, would limit the lifetime of these materials only in the very long term. There is no doubt that coping with certain types of damage caused by ageing or corrosion of materials creates difficult maintenance problems which should be predicted and evaluated. If this necessary effort is made, the lifetime of PWR plants may be very long. (author). 7 figs