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[en] The decision to extend the lifetime of existing plants should be balanced by a significant enhancement of their safety features. It is recognized that more comprehensive and systematic reviews will be performed on the following key issues: Extended ageing management programme; Comprehensive safety reassessment including natural hazards and severe accident management features. Significant modifications are implemented at Kozloduy NPP to minimize the radiological consequences in case of severe accidents. Additional actions are being taken in response to the Fukushima accident. BNRA will take actions to make the process as transparent as possible to stakeholders and public and improve the societal confidence
[en] This paper provides how to establish an integrated plan for LE (Life Extension) and MD (MoDernization) of aged hydropower plants. The methodology is developed through review of overseas/domestic LE/MD histories, investigation of the previous overseas methodologies and consideration of domestic practices. The methodology includes reviews of the various factors such as condition, operation and maintenance history, up-to-date technology, and economic benefit. In order to establish the life extension/modernization plan, the methodology is applied to the domestic aged hydropower plants. Finally, priority rankings and draft practice plans for LE/MD are derived.
[en] There is no specific IS (Information System) which supports the entire scope of a plant life extension, but there are a number of existing solutions that contributes to support it. Globally there are 2 categories of IS solution in the market: those supporting the Plant Life Improvement (PLIM) side of the life extension program and the others supporting the Plant Life Extension (PLEX) process side of it. The first category involves a large number of applications that span from ageing evaluation criteria programs, to monitoring solution for the critical components and to analysis and decision tools. The second category comprises solutions which support partially or globally the overall business process under a regulatory controlled manner. Both categories require 3 conditions to be satisfied: -) a comprehensive set of data (these data are often produced by various applications and the ability to correlate all the data together with a high degree of integrity is an important success factor); -) a feedback mechanism whose dual aspect is the monitoring of the ageing phenomena and the management of all the actions to be coordinated to ensure that preset objectives will be achieved in due time; and -) good people management to ensure particularly that staff will be well acquainted with new equipment or with new operating processes
[en] This paper discusses the changes in the organizational structure of a research and development facility. There is significant amount of change from historically established direction: birth of site and facilities; shift in underlying mission and impact and consequences of changes. There is a need to Shift to More of a Corporate Culture. Every facility and process needs to be re-addressed: increased importance on return on investment; careful balance of safety, quality, efficiency, effectiveness, life extension; current challenge is to shift beliefs and attitudes; risk management vs. risk averse; increase in personal accountability; increase use of contract services to return value; future state or how to solve the issue; processes easier to use better contracting strategies and desire to collaborate with third parties.
[en] A recent opinion survey has been organized to assess how the issue of the lifetime extension of nuclear power plants was understood by the man on the street in France. 20 people have been interviewed after participating to a meeting in which 3 experts from different opinions on nuclear energy have shared their vision of lifetime extension. It appears that lifetime extension is not considered as an issue in itself but belongs to a more important issue that is the future of nuclear energy. Most people do not disagree with the idea of lifetime extension if this extension does not go beyond 10 years and their agreement is strongly correlated with other issues like the management of radioactive waste, the quality and follow-up of sub-contractors and the real alternatives to nuclear energy. 5 profile types have been identified from the most reluctant to the use of nuclear energy who consider lifetime extension as a leap forward in the bad direction to the most confident who agree with both nuclear energy and lifetime extension strategy. (A.C.)
[en] A universal joint also known as universal coupling, U joint, Cardan joint, Hardy Spicer joint, or Hooke's joint is a joint or coupling in a rigid rod that allows the rod to 'bend'in any direction, and is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90 .deg. to each other, connected by a cross shaft. The Cardan joint suffers from one major problem: even when the input drive shaft rotates at a constant speed, the output drive shaft rotates at a variable speed, thus causing vibration and wear. The variation in the speed of the driven shaft depends on the configuration of the joint. Such configuration can be specified by three variables. The universal (Cardan) joints are associated with power transmission systems. They are commonly used when there needs to be angular deviations in the rotating shafts. It is the purpose of this research to study the dynamics of the universal joints and to propose some practical methods for improving their performance. The task is performed by initially deriving the motion equations associated to the universal joints. That is followed by elaborating on the oscillatory behavior in the rotational speed and the torque that transmits through the intermediary shaft. The forces in the joint bearings are calculated by using an analytical method that is also supported by the numerical modeling. Such models are also used in order to calculate the rhythm and the amount of the excess loads on the joint. This is suggested as a systematic procedure in the search for the causes of the failures in these popular bearings. With the same purpose in mind some defected bearings with deformed sections were selected for the laboratory examinations. By analyzing the loading behavior and the surface conditions of the defected bearings and by comparison with the known fatigue theories attempts are made in order to dig into the causes for the failures in these joints and their bearing surfaces. With the aim of improving the performance and the life expectancy of these popular elements of the machineries, some practical recommendations are also suggested
[en] The identification, location and retrieval of foreign objects is essential in order to maintain power plant integrity. It prevents risks related to loose part fretting but also potential damages caused by loose parts when circulating inside plant systems. Therefore visual inspection and FOSAR technologies strongly contribute to lifetime / aging management programs. AREVA's remote controlled combined inspection and search & retrieval solution combines the best of expertise and technology from our global resources to deliver the most cost-efficient, safe and reliable results. We are committed to continual investing so our cutting edge technology can keep evolving. Our number one mission is to safely identify and remove foreign material out of plant systems while minimizing personnel radiation exposure in dose areas. Our system contains positioning unit / feeding manipulator for tape deflection combined with specific cameras, lighting and very flexible modular FOSAR tools. This allows high manoeuvrability as well as rapid assembly and disassembly with low set-up times. A set of easily exchangeable grippers for different FOSAR requirements (e.g. type, size, location of particles) covers a wide range of applications. Additional suction devices and magnets are available on specific demand. Special, highly qualified FOSAR personnel with up-to-date experience ensure optimum performance.
[en] An appropriate maintenance policy is essential to reduce expenses and risks related to equipment failures. A fundamental aspect to be considered when specifying such policies is to be able to predict the reliability of the systems under study, based on a well fitted model. In this paper, the classes of models Arithmetic Reduction of Age and Arithmetic Reduction of Intensity are explored. Likelihood functions for such models are derived, and a graphical method is proposed for model selection. A real data set involving failures in trucks used by a Brazilian mining is analyzed considering models with different memories. Parameters, namely, shape and scale for Power Law Process, and the efficiency of repair were estimated for the best fitted model. Estimation of model parameters allowed us to derive reliability estimators to predict the behavior of the failure process. These results are a valuable information for the mining company and can be used to support decision making regarding preventive maintenance policy. - Highlights: • Likelihood functions for imperfect repair models are derived. • A goodness-of-fit technique is proposed as a tool for model selection. • Failures in trucks owned by a Brazilian mining are modeled. • Estimation allowed deriving reliability predictors to forecast the future failure process of the trucks