No abstract available

[en] A comprehensive analysis in several steps was made in order to estimate the flow induced vibrations of SUPERPHENIX reactor internal structures. This analysis includes calculation and full-scale tests in air, fluid-structure modal calculation and limited verification by tests. In both cases, the calculation used a substructuration procedure. Excitation sources were estimated using reduced scale models. These sources were then introduced in the modal model of the complete fluid-coupled assembly in order to calculate the response in terms of displacements and stresses. The stress responses due to these sources revealed to be below the fatigue stress limits. Their maximum were localized at the points where strain gages were implemented for the control of the reactor behaviour during operation

[en] The Specialists' Meeting on ''Flow Induced Vibrations in FBRs for LMFBR Applications'' was held in Paris under the auspices of the French CEA on 21-24 October 1982. The meeting was sponsored by the IAEA on the recommendation of the 14th Meeting of the IWGFR and was attended by 31 participants from France, the Federal Republic of Germany, India, Italy, Japan, the United Kingdom, the Union of Soviet Socialist Republics, the United States of America and one international organization (IAEA). The meeting was presided over by Pr. R.J. Gibert of France. After the first session on review of national positions in the subject field (7 papers), the meeting was divided into five technical sections as follows: fluid-structures interaction, calculation methods (3 papers); tubes bundles vibration and weir (4 papers); instability (6 papers); induced vibrations in the pumps (2 papers). A separate abstract was prepared for each of these papers

[en] The experimental investigation results on the vibration characteristics of the rods with artificial roughness in the axial flow are presented. It is shown that the roughness plays an important role in the mechanism of vibrations excitation. For the rods having artificial roughness with a relative size of 0.075+0.2 the phenomenon of dynamic instability has been revealed at the flowrates being by the order of magnitude smaller than those predicted by the Paidoussis theory. It is experimentally obtained that for the rods similar to those used as a nuclear reactor fuel element and heat exchanger tubes the critical velocities resulting in the vibration amplitude increase by the one or two order of magnitude are the values as much as 6-12 m/s. It is shown that the phenomenon revealed differs from a classic flutter by a number of attributes. (author)

[en] In the UK flow-induced vibration of LMFBR components is assessed using a combination of theoretical and experimental approaches. Basic development work is carried out to allow more reliance in the future on theoretical methods, which requires better understanding of mechanisms involved where flow patterns are complex. In particular loose-tube vibration in heat exchangers, and the above-core region are being considered for experimental investigations of a generic nature

[en] The complex mechanic systems involving a great quantity of the same type elements, in particular, the rod systems flowed around by the one- or two-phase flow are considered as the two- or three-phase heterogeneous media with certain effective properties. Some recommendations for calculating effective properties and determining those on a base of the dynamic characteristics of various heterogeneous systems are given. (author)

No abstract available

[en] When an array of tubes is subjected to crossflow, the tubes can experience dynamic instability, generally called fluidelastic instability. Instability initiates when the crossflow velocity exceeds a threshold value above which energy input from the flow exceeds that dissipated by system damping. Catastrophic failures of reactor and process plant equipment have been attributed to fluidelastic instability. As a result, extensive research studies have been conducted in the last 15 years with the objective of understanding the instability mechanisms and developing general design guidelines to avoid instability. Argonne National Laboratory has a continuing research program in this area which includes both mathematical model development and experimentation. This paper describes recent developments and accomplishments

[en] Considerable effort has been devoted to understanding flow interaction in tube bundles as these feature prominently in heat exchangers (Steam Generator Unit, SGU and Intermediate Heat Exchanger, IHX) also in CDFR core support and above-core structure. Excitation data has been obtained at Reynolds Numbers Re 0.4-4x10⁵ for a range of triangle pitch geometries appropriate to heat exchangers and at Re up to 2x10⁸ for above core structure. In this paper basic tube-bundle development work is described first, to be followed by application to the various parts of the reactor to which it is appropriate, along with other vibration experimental work and future intentions

No abstract available