[en] During operation, ageing will influence the quality of systems, structures and components (SSC). Experts make a distinction between the phenomena of conceptional ageing, technological ageing and physical ageing. The quality of SSC may be influenced by conceptional ageing, quality, technological or physical ageing. The contribution outlines the preconditions for a comprehensive, standardized ageing management of nuclear power stations in the Federal Republic of Germany. (orig.)

[en] 1. The requirements for correct function of flanged joints are discussed. 2. The specifications of TA Luft concerning design, inspection and in-service inspection are presented. 3. Design, inspections and recurrent inspections are discussed in accordance with the current state of the art. 4. Available procedures are reviewed with regard to comprehensiveness and validity. (orig.)

[en] This conference CD contains the full text of 47 papers on the following subjects: 1. Ageing management; 2. Integrity analysis; 3. Materials engineering; 4. State monitoring; 5. Pressure equipment status monitoring; 6. Quality assurance; 7. Non-destructive testing; 8. Fracture-mechanical analysis of components

[en] In the context of OECD Pipe Failure Data Exchange (OPDE), a data base was established on pipeline damage in nuclear power stations. The data base contains information on incidents in safety-relevant pipelines, e.g. leakages, fracture and rupture. Twelve countries contributed in the project. Based on an existing database, the first update phase was started in 2002-2005. The second phase will go on until 2008. Currently, more than 3,600 incidents are recorded in the database, which is available in Microsoft Office Access and is to help users solve problems relating to various aspects of nuclear pipeline systems. (orig.)

[en] The findings obtained in recurrent inspections as a rule are evaluated by fracture-mechanical analyses. On the basis of the results, it is decided whether a component must be repaired or if operation can continue as it is for the time being. The two-criteria method is applied as a rule because of its universal applicability. Limited ductile crack growth can be taken into account if crack resistance curves are available that can be transferred to the component in question. In the investigations presented here, the influence of the relevant initial variables, e.g. strength coefficents, fracture-mechanical material coefficients, primary and secondary stresses and the intrinsic state of stress is illustrated by exemplary calculations. Further, the safety concepts underlying the assessment are gone into. (orig.)

[en] The contribution outlines the comprehensive integrity concept for pipelines in German nuclear power stations along with the leakage and fracture postulates that must be applied. Further intentions are: 1. A chronological representation of the fracture exclusion concept as developed during the past two decades and a half; 2. Representation of the system-specific implementation of this integrity concept in licensing and supervisory procedures; 3. Representation of the current state of science and technology; 4. Presentation of operating experience so far; 5. Comparison of this integrity concept with procedures of other countries, especially the US concept. (orig.)

[en] In nuclear power stations as in other industrial plants, there are active and passive components whose failure is permissible only in exceptional cases both from a safety and/or economic view. Failure in this context means loss of integrity of a supporting wall, insufficient function and/or unstoppable leakage. A systematic defect must be excluded as cause of failure; the consequences of failure must be manageable. During operation, measures must be taken to maintain the required quality and detect consequences of damage mechanisms at an early stage, prior to failure. This is achieved by preventive maintenance in accordance with the latest state of knowledge. To exclude systematic errors, the quality standard of components must be re-checked every once in a while as the effects of damage mechanisms and the state of knowledge are time-dependent parameters. This requires an integrated concept, e.g. for life and ageing management, in whose context a comprehensive knowledge base is developed and regularly updated. (orig.)

[en] Thermal fatigue is one significant long-term degradation mechanism in nuclear power plants (NPP), in particular, as operating plants become older and life time extension activities have been initiated. In general, the common thermal fatigue issues are understood and controlled by plant instrumentation systems. However, incidents in some plants indicate that certain piping system Tees are susceptible to turbulent temperature mixing effects that cannot be adequately monitored by common thermocouple instrumentation. The THERFAT project (Thermal fatigue evaluation of piping system Tee-connections) had been initiated to advance the accuracy and reliability of thermal fatigue load determination and to outline a science based but still practical methodology for managing thermal fatigue risks in Tee-connections susceptible to high cyclic temperature fluctuations. The THERFAT project was carried out by 16 international Partners (utilities, plants vendors/manufacturers, consultant engineers, research institutes) as a cost shared action funded by the European Commission. (orig.)

[en] The microstructure of ferritic-martensitic 9-12% Cr steels in the initial state promises ideal preconditions for application in power plant components under high thermal load, e.g. turbinecomponents and pipes, but many of these steels show reduced fatigue strength already after about 10,000 hours of operation. These are caused by microstructural changes, e.g. coarsening, dissolution of precipitations, formation of undesired phases, coarsening of subgrains, formation of martensite structures and creep pores. The contribution presents a holistic approach for a comprehensive problem description. The microstructure is investigated by EFTEM and EBSD, and the development of precipitations is also investigated using the new thermokinetic computer model MatCalc. The results can be used for long-term predictions of creep strengths of existing and new alloys, e.g. by the so-called backstress concept. (orig.)

[en] Thin-walled welds (less than 10 mm wall thickness) in austenitic pipes and mixed welds are difficult to test using non-destructive methods. This is true especially for detection of closed cracks, which is impossible by radiographic testing and problematic by ultrasonic testing. Several projects in reactor safety research provided better understanding of the testing characteristics of thes compounds. The resulting rules for writing of test specifications and for qualification of the technology employed also showed the limits of radiographic and ultrasonic testing. One important result was the simulation of the propagation of ultrasonic waves in model descriptions of welded structures as a function of the shape of the product. This allows, in principle, the applicaiton of ultrasonic migration techniques which enable consideration of phase disturbances gy structural anisotropy when the time signals of the ultrasonic sensor elements are summed up. The applicability of this 'inverse phase adaptation' was proved in heterogeneous and anisotropic model test bodies and on test bodies of the reactor safety programme. The contribution outlines the fundamentals of the technology and presents preliminary findings. (orig.)