NDTsi 2001 Session: Structural Integrity and NDE I-II
Pressure Vessel Integrity: Demonstration of Life Extension to Thirty Years
F. Champigny, G. Bezdikian, EDF, France
ABSTRACT
In France, no law or industrial code authorises a nuclear plant to have a life extension up to 40 years. Particularly, since the last departmental order signed at the end of 1999, the licensee has to review every ten years the conception and operation dossier established for a standardised series and also for each plant. In this frame, the life extension of the pressure vessel is considered as very important and Electricité de France has prepared for the case of the core area a justification taking into account many parameters like neutron embrittlement, surveillance program for irradiation, non destructive examinations and fracture analysis. For what concerns these issues, the demonstration has been performed on the basis of a virtual RPV where all the parameters are considered as worst cases. It was shown that 900 MW RPV can operate up to 40 years. On the other hand, when a flaw is detected and characterised, a specific demonstration is made to show that with the data of the RPV (material, flaw characteristics, fluence at the location of the flaw, ...) safety margins are sufficient to be in agreement with the law requirements. This paper describes the necessary steps used to show that French RPVs are acceptable for 40 years and particularly after the discovery of the flaws on the unit 1 of Tricastin. All necessary justifications were given to the Safety Authority, which agreed the life extension up to 30 years.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
