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"Estimation of the sizes of coherent scattering areas in alloys based on neutron diffraction data"
Erzhanov Bekarys (FLNP JINR, KFU Institute of Physics, Kazan, Russia)
The results of the analysis of the diffraction spectra of the Fe74Al26 alloy, measured on a high-resolution neutron diffractometer, aimed at determining the size distribution of structurally ordered clusters dispersively embedded in a structurally disordered alloy matrix are discussed in the report. For this purpose, generalization of the Scherrer method based on the analysis of diffraction peak profiles, determination of peak widths at heights of 1/5 and 4/5 from the maximum and the assumption that the gamma distribution is valid for cluster sizes (Pelaszek's method) has been used.
The results obtained by the Scherrer, Williamson-Hall and Pelasek methods are compared and their good agreement with each other is shown. An algorithm for calculating a physically more reasonable logarithmically normal distribution is proposed. The experimental data were obtained on a time-of-flight neutron diffractometer, therefore they were analysed for two variants of the scanning variable: in the crystalline (d-scale) and inverse (H-scale) spaces and estimates of possible systematic errors were obtained.
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Agenda:
"Design and development of neutron detectors based on the 6LiF/ZnS(Ag) scintillator"
Maksim Podlesnyj (based on Ph.D. thesis)
Specialty 1.3.2 - "Instruments and methods of experimental physics"
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Agenda:
1. Changes in the membership of the FLNP STC due to the elections.
2. Elections of the Chairman and the Scientific Secretary of the FLNP STC.
3. Discussion of the Regulations on the FLNP STC.
4. Miscellaneous.
All interested staff members are welcome
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Agenda:
1. Defense of the Ph.D. thesis by Nguyen Van Tiep (FLNP JINR) "Features of helium swelling in ferritic alloys".
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"Simulation of dynamic bending of inhomogeneous fuel rod"
A.E. Verhoglyadov
To accurately simulate the dynamics of a pulsed reactor, it is necessary to know the shape of the fuel rod at the moment of the next power pulse. Since the numerical methods for solving this dynamic problem of thermoelasticity require too much computation time, an analytical method was applied. The problem of finding the natural frequencies and eigenfunctions of an inhomogeneous rod is solved. Analytical expressions for eigenfunctions are obtained; they give a good match with calculations using the Galerkin method and the ANSYS calculations.
The results of the numerical-analytical solution of the equation of motion of an inhomogeneous fuel rod are compared with the solution by the finite element method (ANSYS). The prospects for using the method in studying the dynamics of the NEPTUN reactor are considered.