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The instrumented indentation method, based on the digital recording of the parameters of the entire process of continuous local deformation of the material by an indenter, provides more complete and accurate information about the material's behavior under load. Obtaining such information without compromising the integrity of a critical structure during operation increases its value. Therefore, more and more attention has recently been paid to portable installations and devices that use the instrumented indentation method. To date, no such equipment is manufactured in Ukraine. Therefore, there is a need to develop portable equipment for conducting such tests in the field under various modes of static and cyclic loading in the macro range of forces. The paper describes an updated portable installation PIIT-02M for determining the strength characteristics of structural elements in service by instrumented indentation, which was developed following the requirements of ISO 14577 and is intended for testing at the macro level. The system of fastening the portable installation on the test object was updated from mechanical (hooks and chains) to electromagnetic. This made it possible to conduct tests on pipes and flat surfaces, including sheet materials and structures made of them, significantly increasing the test efficiency and expanding the range of applications. Comparative tests on a 12 mm thick structural carbon 20 steel plate using the previous mechanical fastening system and the new electromagnetic one showed that the indentation diagrams obtained overlap well. Based on the results of tests of high-strength steels, the portable installation PIIT-02M allows one under both laboratory and operating conditions to record the process of indentation of the indenter into specimens of structural materials with high accuracy and, accordingly, to determine their mechanical characteristics by instrumented indentation. [ABSTRACT FROM AUTHOR]

The main normative documents for the nuclear power industry of Ukraine, which regulate the determination of mechanical characteristics from hardness measurement data, are considered and analyzed. It has been shown that the use of these documents for monitoring the technical condition of the equipment of nuclear power stations, in particular of the metals of the bypass pipeline of the high-pressure pump SAOZ of the core emergency cooling system (08Kh18N10T steel), coil from the welded joint zone of the Du 600 inlet branch pipe of the IRA30S02 non-return valve (16GS steel), and the body shell of the dismounted PV2500-97-10A (09G2S steel) high-pressure heater calls for their more detailed justification. To determine the mechanical characteristics of metals and to increase the reliability of their evaluation in nondestructive monitoring, a standard developed by the Pisarenko Institute of Problems of Strength of the National Academy of Sciences of Ukraine is used. According to this standard, the evaluation is made not only on the basis of hardness measurement data, but also by the method of instrumented indentation. It has been shown that this method is more efficient for the determination of the strength characteristics of steels. The difference between the ultimate strength and yield strength values according to this standard and those obtained in tensile tests is not over 8.6% and not over 6.6%, respectively. When diagnosing the technical condition of the metal of pipelines, indentation tests allow one to determine strength characteristics not only in the axial and tangential directions, but also in the radial direction. [ABSTRACT FROM AUTHOR]

General methodological approaches to solving the problems of strength and life of NPP equipment and results recently obtained in this field at the Pisarenko Institute of Problems of Strength of the National Academy of Sciences of Ukraine are outlined. The urgency of the strength and life issues for reactor pressure vessels and steam generator shells is demonstrated. Application of a comprehensive calculation and experimental approach to the stress-strain state analysis is illustrated by the example of steam generator joints with defects. [ABSTRACT FROM AUTHOR]