PWR life evaluation project of edf

Abstract

The massive contribution to power generation of its recent PWR has provided the Electricite de France with a strong incentive to carefully examine the potential for the safe and economical service life of these units. Due to their low fuel cost, and to the lack of likely competitors, LWR systems should be ensured of a long future, by comparison with previous thermal facilities. Moreover, the moderate level of thermal performances, as well as the sophisticated design methods applied to the main components give them the best inherent chances of endurance. In 1986 EDF undertook an important programme of work on this subject. In the first phase, all available elements are gathered and reviewed, from design, fabrication, in-service experience and surveillance. Thereafter, complementary studies will be made as far as necessary to improve the knowledge and the control of aging processes, and optimize the maintenance and operation practices. Preliminary conclusions can be drawn from the ongoing studies. Favourable statements can be made regarding the fatigue resistance of the main primary circuits, the irradiation aging of the RPV and the basic behaviours of the main containment structures. In spite of some concern with respect to SG tubing corrosion, which could lead to higher maintenance and repair costs higher than wished for the oldest units, there is no doubt that most of the units will be able to supply a service life of at least 40 years and probably longer.