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Petosic A.,University of Zagreb | Corak Cvjeticanin Z.,INETEC Institute Za Nuklearnu Tehnologiju INETEC Institute for Nuclear Technology | Budimir M.,INETEC Institute Za Nuklearnu Tehnologiju INETEC Institute for Nuclear Technology
Strojarstvo | Year: 2011

The electrical excitation dependence of working parameters of a normal beam non-destructive evaluation ultrasound transducer has been investigated. Noteworthy differences between the transducer input electrical impedance and acoustic properties at low excitation voltages (∼1V), most often used in electromechanical characterizations by performing frequency sweeps, and at high excitation voltages (∼250V), generally used to drive ultrasound transducers in non-destructive evaluation applications, were emphasized. For the purpose of this work, a circular normal beam ultrasound transducer of centre frequency 2 MHz was constructed by using a PZT piezoelectric disk, epoxybased acoustically passive front matching and backing layers, an electrical impedance matching element, housing and coaxial cable. The transducer was characterized around the thickness extensional vibration mode both by using low and high voltage electrical excitation signals. The characterization of the electromechanical properties was conducted at several different stages of the transducer construction and for several excitation signal waveforms and levels. Source


Cvjeticanin Z.C.,INETEC Institute Za Nuklearnu Tehnologiju INETEC Institute for Nuclear Technology | Budimir M.,INETEC Institute Za Nuklearnu Tehnologiju INETEC Institute for Nuclear Technology | Vavrous M.,INETEC Institute Za Nuklearnu Tehnologiju INETEC Institute for Nuclear Technology
Strojarstvo | Year: 2011

The main task of every nuclear power plant owner is to establish the balance in taking precautions such as monitoring, inspection and corrective actions, with the aim of retaining the steam generator integrity. The steam generator integrity assessment presents the key factor in achieving the mentioned aim. It is necessary to conduct a wide range of researches for a quality of steam generator integrity assessment. One of the key elements as well as starting point for steam generator structural integrity assessment is establishing burst pressure relationship for each degradation mechanism orientation, type and their location on steam generator tubes. This paper presents the role of burst pressure relationship within VVER steam generator structural integrity assessment and its determination. In addition to this, the results of researches for the axially oriented flaws on the free span will be presented, with the aim of establishing burst pressure relationship. Source

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