Probabilistic Analysis of the Reliability and Fatigue Life of Machine Parts by Fatigue Failure

Journal of Machinery Manufacture and Reliability - The problem of calculating the reliability and fatigue life of machine parts by the fatigue failure under random changes in the actual and limit...     

Solution of inverse problems of radiative transport by soot particles of complex shapes

We work out a method of determining the effective parameters of soot particles from their radiation characteristics. The method is based on the measurements of the spectral transmission coefficient in the infrared region of the spectrum.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 6, pp. 921–925, December, 1985.     

Restoration of metal properties of circulation pump blades by the method of surface ultrasonic impact treatment

During the transition period to a market economy, the works producing equipment for the nuclear industry became lame duck companies. The market of heavy industry equipment reduced dramatically, and quality control requirements imposed to goods became lower. Deviations from regulations' requirements and technical specifications for equipment manufacture results in inevitable decrease of reliability during operation but also to failure during check tests. It is not always possible to replace promptly ill-conditioned equipment; in such cases, it is necessary to carry out compensatory measures for restoring working properties up to an acceptable level in order to ensure operational reliability due to the strength improvement of the components of machines and constructions during the whole service life or up to the scheduled date of equipment replacement. This paper is dedicated to development and practical implementation of restorative technology of strengthening ultrasonic treatment used for the metal of the blades of impellers of 16DPA10-28 circulation pumps of 10URS unit pump station located at Novovoronezh NPP-2. The dynamic surface treatment was implemented for compensating the technological defects of the metal of blades. It was revealed that the impact elastic-plastic deformation has a comprehensive compensation effect on the metal of blades in the initial state of delivery and creates the surface-strengthening layer with higher strength properties (strain hardening) of the depth up to 1.5 mm. The surface strain hardening increases the cyclic strength, re-distributes beneficially the residual technological and repair stresses, and heals small surface cracks improving the surface quality. The developed technology was used for treatment of 32 blades of impellers of 10PAC01AP001, 10PAC02AP001, 10PAC03AP001, 10PAC04AP001 circulation pumps. The implemented 100-h full-scale test of the pumps revealed the high efficiency of the developed technology and made it possible to recommend it for application at both the stage of blade manufacture and during the pump operation for prolongation of their service life.     

Photoconductivity of Ge1-xSix single crystals in the range 115–300 K

The steady-state photoconductivity ofn- andp-type Ge_1-xSi_x single crystals was measured in the range 115–300 K. The results were interpreted using a model considering two types of centers with markedly different capture cross sections.     

Experience of vindicating extension of the design lifetime of the pipelines in nuclear power plants with fast neutron reactors

An approach to extension of the design lifetime of pipelines in fast neutron reactors to 45 years of operation is proposed. For this purpose, a nondestructive method for testing metal under creep under operating conditions without using specimens is developed. The method is based on long-lasting indentation of a ball indenter in the most heavily loaded areas of the pipelines. A relation between the tensile creep and indentation creep parameters is obtained.     

Microstructure and mechanical properties of welded joints of NPP pipelines after long-term operation

The microstructure and mechanical properties of welded joints of cuts from Du 300 and Du 500 pipelines of the Leningradskaya and Novovoronezhskaya nuclear power plants are studied after 70 and 100 thousand hours of operation. The effects of thermal aging simulating operational impact on the microstructure and properties of welded joints of the cuts and of a model coil are determined. It is shown that long-term operation can be accompanied by embrittlement and decrease in the crack resistance of the metal of welds in Du 300 and Du 500 pipelines produced from steels 08Kh18N10T and 08Kh18N12T. The discovered changes in the microstructure can lead to deterioration of the mechanical properties of the metal of welded joints in operation of Du 300 and Du 500 pipelines. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 36–42, July, 2006.