[en] The EUR (European Utilities Requirements) is an organization founded in 1991 whose aim was to write down the European specifications and requirements for the future reactors of third generation. EUR gathers most of the nuclear power producers of Europe. The EUR document has been built on the large and varied experience of EUR members and can be used to elaborate invitations to tender for nuclear projects. 4000 requirements only for the nuclear part of the plant are listed, among which we have: -) the probability of core meltdown for a reactor must be less than 10^-6 per year, -) the service life of every component that is not replaceable must be 60 years, -) the capacity of the spent fuel pool must be sufficient to store 10-15 years of production without clearing out. The EUR document is both open and complete: every topic has been considered, it does not favor any type of reactor but can ban any technology that is too risky or has an unfavourable feedback experience. The assessment of the conformity with the EUR document of 7 reactor projects (BWR 90/, EPR, EP1000, SWR1000, ABWR, AP1000 and VVER-AES-92) has already be made. (A.C.)

[en] At the end of 1986, thirty-three 900 MW PWR units and nine 1300 MW units are in service. In application of regulations, a program to monitor the effects of irradiation on vessel materials is being performed. It involves the base metal, the heat affected zones (HAZ) and the welds. The contents of embrittling elements are low: 0.08% copper to 0.011% phosphorous maximum, except for the welds of the six oldest vessels, where copper reaches 0.13%. The results obtained to the present are presented in the RTNDT differences. The fluences recorded reach 1.5 /times/ 10¹⁹ n /center dot/ cm/sup /minus/2/ E > 1 MeV on specimens removed after four years, which corresponds to approximately 12 years of operation, considering the multiplying factor of flux. The average and upper values of difference of the RTNDT are respectively 20/degree/C and 40/degree/C and there is no notable difference between the base metal and the welds. The results obtained are compared with the indications of the various forecasting formulas, specifically with those of a new formula that has been established. 3 refs., 2 figs., 5 tabs

[en] EDF aims at extending the operating life of nuclear reactors largely over 40 years. This industrial-scale program relies on a continuous process of improving both safety and performances and on taking aging and equipment obsolescence into account. A realistic assessment of the margins in all the domains of equipment behaviour is required. The maintenance operations are based on diagnostics benefiting from last progress in simulation, real situations or experimental programs. Examples of applications concerning reactor vessels, primary loops or corrosion issues are presented. (A.C.)

[en] In this paper there are an analysis and description of: - the industrial stakes associated to lifetime management in particular questions which have to be investigated; - the meaning, processes and content of the lifetime management approach within EDF: - 10 years safety reassessment, taking into account, on one hand, safety compliance demonstration and, on the other hand, safety reassessment, the aim of which is to upgrade safety level (seismic analysis, hazards, severe accidents, ...). A cost/benefit methodology has been defined to rank the pertinence of plant modifications. The results concerning 3 loops plants thirty years decennial outage program are presented. - Ageing management principles, based on feedback experience of a large standardized fleet, including a dedicated process for obsolescence problems, and an anticipation approach (examples are given: alloys 600 areas, thermal fatigue, ...). - Research and development support activities, in relationship with safety criteria, industrial decisions. - Skills management, internally for the company and those of industrial operators, subcontractors, in the field of design, manufacturing and maintenance: - Evolution of job needs (engineering and operation); - Medium and long term vision, in particular for sensible skills; - Skills transfer because of high rate of retirement

[en] French surveillance program on low alloy Mn Ni Mo vessel steel constitutes, a noteworthy group of results, in consideration of great number of available data, materials and operating conditions homogeneity, and its centralized performance. Irradiation embrittlement of 900 MW vessels, for 3/4 lifetime, is moderate and less than one prevued in most cases. The maximum value for mean predicted RT_NDT of 28900 MW vessels is less than 70⁰C (158⁰F). Therefore, because of fast fracture results concerning operating vessels and ability of inservice inspection to detect any underclad defect higher than 3 mm, safety operating margins are adequate. Works are carrying on to complete the knowledge of in service behaviour and life time of vessels

[en] Full text: Plant life management (PLiM) of the 58 EDF nuclear plants is in the core of an energy strategy which integrates durable development, supplying security, safety and competitiveness. Three main stakes are linked to the EDF fleet PLiM : - to assure permanently a high level of safety in operation, with a continuous increase of safety level; - to increase the economic value of such an industrial tool, taking into account the advantage of a standardized fleet, and dealing with the potential vulnerability effect induced ; - to participate to the industrial solution required to permit a new built smoothing, in comparison with the high initial rhythm of nearly 50 Gwe, during the 80's. In this paper there are an analysis and descriptions of: - the industrial stakes associated to lifetime management in particular questions which have to be investigated, - the meaning, processes and content of the lifetime management approach within EDF: - 10 years safety reassessment, taking into account, on one hand, safety compliance demonstration and, on the other hand, safety reassessment, the aim of which is to upgrade safety level (seismic analysis, hazards, severe accidents,...). A cost/benefit methodology has been defined to rank the pertinence of plant modifications. The results concerning 3 loops plants thirty years decennial outage program are presented. - Ageing management principles, based on feed back experience of a large standardized fleet, including a dedicated process for obsolescence problems, and an anticipation approach (examples are given: alloys 600 areas, thermal fatigue, ...) - Research and development support activities, in relationship with safety criteria, industrial decisions, - Skills management, internally for the company and those of industrial operators, subcontractors, in the field of design, manufacturing and maintenance : - Evolution of job needs (engineering and operation), - Medium and long term vision, in particular for sensible skills, - Skills transfer because of high rate of retirement. (author)

[en] In 1986, some irradiated specimen of CHOOZ A (SENA) vessel showed a significant excess of δ RTNDT to former previsions. The lack of data on one of the two irradiated shells, and discrepancies between dosimeters results and available previous fluence calculations whose accuracy was questionable, cause the safety authorities to require an important complementary work program before putting again the plant on the grid after 1987 fuel reloading. These works are presented and discussed. They lead to a state that a conservative to day value of the vessel RTNDT is 64 degrees Celsius and that there is no underclad defect in the vessel wall and welds. Then the plant was allowed to restart with certitude that vessel irradiation will not impair its lifetime. (author)

[en] The failure rates of the following components, valves operating in sodium, mechanical and electromagnetic pumps, and heat exchangers including intermediate heat exchangers, cold traps, steam generators, are evaluated by analysing the main incidents which occurred on these components. Therefore, this paper contains an evaluation of the operating experience of components working in sodium and of the reliability of these components

[en] EDF (the French electricity company) benefits a feed-back experience of about 1000 year-reactor and a standardized park of reactors. EDF's policy of maintenance has evolved to satisfy objectives of safety, availability, radiation protection and cost reduction. In EDF plants maintenance actions can be divided into 2 types: preventive actions (2/3) and repair actions after failures (1/3). Technical and industrial mastery of maintenance is based on 5 elements: 1) the feedback experience which allows to detect any generic problem, 2) the setting of preventive maintenance programs for equipment and systems, 3) the survey and analysis of removed parts, 4) the preparation of the future by developing a capacity to anticipate, and 5) the management of the obsolescence of the couple supplier-product among the contractors working with EDF. (A.C.)

[en] The experience return has shown it: to evaluate the threats for the park on the materials or systems, to have at one's disposal the right answers, is a necessity for safety and competitiveness of the nuclear kWh. We present the technical, industrial and organisation bases on which future is prepared, especially to engineering plans, R and D, operational aspects. Some examples illustrate the approach. (N.C.)