[en] In the present paper, the aspects of optimizing In-Service Inspection (ISI) is discussed. Slovenian Nuclear Safety Administration (SNSA) and its authorized organization for the ISI activities, Institute of Metals and Technologies, are permanently involved in the ISI process of the nuclear power plant (NPP) Krsko. Based on this experience and additionally gathered by reviewing of the new ISI program, the decision was made to improve recent regulatory and professional practice. Traditional criteria, standards and practice are bases for the further improvements. Improvements will be done by adding a new knowledge about the safety important components of the systems to the basic practice. It is necessary to identify conditions of the safety important components, such as realistic stress and fatigue conditions, material properties changes due aging processes, the temperature cycling effects, existing flaws characterization in the light of the previous detection and equipment technique used, assessment of the measurement accuracy on the results etc. In addition to the above mentioned, risk assessment and evaluation of the whole ISI shall be done. To do this it is necessary to make risk evaluation, based on previous structural element probability assessment. Probabilistic risk assessment is important and one of the most powerful tools in the ISI optimization. Some basic work in the field of the risk informed methods related to the nuclear safety components has been already done. Based on reference documentation, the most important steps in risk informed ISI are discussed. Those steps are scope definition, consequence evaluation, failure probability estimation, risk evaluation, nondestructive examination method selection and possibilities of implementation, monitoring and feedback. Recent experience on the ISI in the nuclear world show that such practice is very important during ISI decision making process and has some measurable effects too. It is clear that classical criteria for the selection of ISI inspection locations are not completely in accordance with current measures of nuclear safety. ISI optimization shall give benefits to the operator of nuclear facility (on the resources and duration of the ISI inspections) and to the SNSA (more effective control of the safety important components, aging management control and overall nuclear safety).(author)

[en] The full text follows. Peach Bottom Atomic Power Station (PBAPS) has always been proactive with respect to inspection of its boiling water reactors. Internal visual in-service inspections (IVVI) of the reactor vessel internals have been conducted at the PBAPS for many years. The scope and methods of these inspections were primarily driven by conservative interpretations of the American Society of Mechanical Engineers (ASME); Boiler and Pressure Vessel Code, Section XI, 'Rules for In-service Inspection of Nuclear Power Plant Components'. In addition, industry recommendations, regulatory requirements augmenting Code guidance, and investment protection were also used for guidance. With the formation of the Boiling Water Reactor Vessel and Internals Project in 1994, comprehensive and systematic guidance for the inspection of the reactor internals became available. Inspection recommendations, along with defendable methods for dealing with identified degradation were published on an ongoing basis. This consistent guidance enabled PBAPS to more crisply focus its resources on the appropriate inspections of its reactors. The guidance allowed retention of the proactive inspection effort, and provided the ability to develop a more proactive program for dealing with inspection results. The BWRVIP guidance also enabled sound decisions regarding repair or replacement of internal components, as well mitigation measures that could be undertaken to reduce or eliminate the internals degradation phenomenon. The objective of this paper is to explain the approach used by PBAPS to integrate the evolving BWRVIP guidance into its existing Inservice Inspection Programs. Additionally, the paper will describe specific scenarios that occurred during the implementation of this effort, and the approach used by PBAPS to apply the BWRVIP guidance toward resolution of the related issues. The paper will provide a model for successful use of BWRVIP products, and explain the process used to satisfy commitments made by this Industry Initiative on behalf of its participating utilities. (author)

[en] Surveillance techniques are based on the detection of changes. These changes can be caused by moving objects or people, or by modifications made to the environment itself. Visual surveillance uses optical means, e.g., the analysis of an image acquired by a surveillance camera. These techniques are effective in detecting objects moving within the surveyed area. There are situations, however, where optical surveillance may prove to be unreliable. In some cases, the changes in the image are too small to be properly detected with scene change detectors. In other cases, alarms are generated without objects (or people) moving. These false alarms may be caused by changes in illumination, e.g., a faulty lamp or spurious reflections in places near water pools. Further, the absence of illumination during a blackout (whether it is caused by accident or on purpose) prevents cameras from their surveillance operation. There are high security installations for which it is necessary to introduce reliable, independent and effective sensors that can keep the surveillance work even during a blackout. Laser range scanners are electronic instruments measuring the distance from the instrument itself to the outside world along a specific direction. The type of the instrument to use depends on the range of distances to measure. Indeed, whereas for large distances (e.g. between 1 and 200m) it is possible to use time-of-flight instruments, for short distances (e.g., from a few centimetres to about 1.5m) a triangulation laser striping system is used. The deflection of the laser beam (e.g., using rotating mirrors) enables the acquisition of the distance profiles (or matrices) of the surrounding premises in a very short time

[en] Steam Generator (SG) parts are intensively inspected by UT in the course of the manufacturing process. These inspections - mostly performed manually using different codes - are time consuming and call for a sophisticated documentation, figuring part of the life time documentation package. In order to reduce time and costs mechanized inspection equipment is introduced, combining short inspection times, avoiding influence of the human factor and providing proper electronic storage of all inspection results prepared for comparison with data generated during in-service inspection. Since 2001 Cegelec delivered various UT systems for gas turbine disks and rotor ends called SIRO-MAN. Within only a few years the majority of important providers of such components successfully switched from manual inspection to mechanized inspection following the requirements of manufacturers like ALSTOM, GE and Siemens. The SIRO-MAN is now adapted to the needs of mechanized inspection of SG components. The inspection is performed on the products during rotation around the vertical axis. The multi - probe assemblies are manoeuvred on the products by a manipulator system backed by a NC control unit. Acoustic coupling of UT probes to the product surface is performed with oil or water in a closed circuit. UT and - if requested ET - data along with position information of the probe assembly provided by the control unit are acquired, processed and evaluated by an UT / ET electronic system delivered by either Olympus or ZETEC. As performed already on rotor ends a sequence of inspections using different parameter settings can be programmed with simple means (Teach In) so that such inspection sequence can be executed without operating personnel. Probe assemblies allow for individual operation of probes out of the probe assembly according to the individual needs. Conventional UT and phased array applications or combination of both techniques can be provided. The UT / ET electronic equipment offers the capability of automatic optimizing the inspection speed thus reducing the inspection time to a minimum. Full A-scan (HF information), peak and gate data acquisition can be selected. After performing the inspection resp. the inspection sequences the inspector can check the results before loading them to the network of the manufacturer for final storage on the server. If defects were found these defects can be automatically listed in an indication table providing all information necessary (location, size) to decide on the further procedure. (author)

No abstract available

[en] The theoretical and experimental study of the propagation and radiation of leaky Lamb wave in a plate waveguide sensor has been carried out. In the plate waveguide sensor, the A₀ leaky Lamb wave is utilized for the single mode generation and the effective radiation capability in a fluid. The plate waveguide sensor which consists of a plate waveguide, a teflon wedge and an ultrasonic sensor has been designed and manufactured. The tone-burst excitation of high power long pulse should be applied to minimize the dispersion effect in 10 m long distance propagation of the A₀ Lamb wave. A novel technique which is capable of steering a radiation beam of a waveguide sensor without a mechanical movement can be achieved by a frequency tuning method of the excitation pulse in the dispersive low frequency range of the A₀ Lamb wave. The characteristics of radiation beam of ultrasonic waveguide sensors has been investigated by the beam profile measurements according to the plate thickness, the radiation aperture length, the pulse cycles and the excitation frequency. The design parameters of the plate waveguide sensor has been optimized. The C-scanning experiments in water have been carried out for the performance of the optimized ultrasonic waveguide sensor. The poulsbility of C-scan visualization using the plate waveguide sensor has been verified

[en] With the inception of the Philippines commercial nuclear power industry, preparatory measures are needed to motivate and maintain public confidence in this extremely valuable energy source. One of these measures is the establishment of in-service inspection (ISI) program for the nuclear power plant throughout its 40-year lifetime. This thesis proposes an in-service inspection program for the country's first nuclear power plant (PNPP-1). The proposed ISI program has been developed based on the requirements of a widely adopted code for nuclear in-service inspection - the section XI of the ASME Boiler and Pressure Vessel Code entitled ''Rules for Inservice Inspection of Nuclear Power Plant Components''. The proposed ISI program complies with the requirements of the 1977 Edition of the ASME Section XI Code with Addenda through the summer 1978. It provides the most acceptable licensee commitments, and the latest techniques currently being utilized abroad in performance of an ISI. The proposed program is beneficial to the licensee in the sense that it could be adapted to the PNPP-1 with very slight modification. To the regulatory authority, the proposed ISI program is valuable in evaluating the adequacy of the ISI plans and schedules that will eventually be submitted by the licensee for approval. (Author). 15 refs.; 5 tabs.; 3 figs. Appendices p. 116-175

[en] In a sodium-cooled fast reactor (SFR), an in-service inspection (ISI) is necessary to examine the integrity of its safety related structures. ASME Section XI Division 3 provides rules and guidelines for an in-service inspection of the components of a SFR. For the ISI of reactor internals, a visual examination and continuous monitoring are adopted for the major inspection techniques. For the dissimilar metal welds and the high stress components such as a reactor support structure, a volumetric examination using an ultrasonic test should be applied. As liquid sodium is opaque to the light, a conventional visual examination can not be used under a sodium condition. An under-sodium viewing (USV) technique using an ultrasonic wave should be applied for the visual examination of the reactor internals. Recently a new plate-type waveguide sensor has been developed for USV applications. An under-sodium visualization of an ultrasonic waveguide sensor was successfully demonstrated in previous research works. In this study, the possibility of a volumetric examination by using a waveguide sensor is confirmed. The comparison tests between the waveguide sensor and the commercial immersion ultrasonic sensor are carried out

[en] A method suitable for inspecting large components, such as nuclear boiler shells, utilising red dye penetrant and a powder developer applied electrostatically, is described

[en] The IAEA started the OSART (Operational Safety Review Team) programme in 1982 to advice and assist IAEA-countries in the improvement of nuclear safety and radiation protection in operating nuclear power plants. A brief overview is given of the aim, organization, and method of inspection of the OSART