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More precise definitions of the perturbation theory formulas for reactivity effects calculations

Jun 28, 2017, 5:50 PM
1h 10m
Yekaterinburg

Yekaterinburg

POSTER Track 6. Test Reactors, Experiments and Modeling and Simulations Poster Session 2

Speaker

Mr boris abramov (Joint Stock Company "State Scientific Centre of the Russian Federation – Institute for Physics and Power Engineering named after A. I. Leypunsky")

Description

More precise definitions of the perturbation theory formulas for reactivity effects calculations B.D. Abramov Leading Scientist of IPPE, Obninsk, Russia. E-mail: abramov@ippe.ru Abstract The paper is devoted to the issues of development and modification of methods of evaluation of reactivity effects in nuclear reactors using perturbation theory. It has been demonstrated for the first time that traditional relationships of small perturba-tion theory used for evaluation of reactivity effects caused by perturbation of neutron-nucleus interaction cross sections should be improved. This improvement would include accounting for the new reactivity effect arising from possible rapid changes (discontinuities) of diffusion coefficients on the interfaces of reactor cells (zones) in the course of disturbance. There have not any references to this effect in the publications available. However, the similar reactivity effect related to the emergence of discontinuities of neutron diffusion equation coefficients on the interfaces of cells caused by thermal strains was described in the paper “The “virtual” density theory on neutronics: a generic method for geometry distortion reactivity coefficients” by M. Reed, K. Smith, and B. Forget, ‘Physor 2014”. In this paper, an effort was made to improve the well-known method by S.B. Shikhov et al., as regards accounting for the more common type strains accompanied by changes in size, form and relative positions of the re-actor cells during thermal perturbation. The propositions presented in the above pa-per were modified by B. Abramov and R. Raskatch (“On some methods of evalua-tion of reactivity effects in deformed reactor cores”, Issues of Atomic Science and Technology, Series: Nuclear Data for Reactors, 2015, pp. 18-32).

Country/Int. Organization

Russia, Obninsk, IPPE

Primary author

Mr boris abramov (Joint Stock Company "State Scientific Centre of the Russian Federation – Institute for Physics and Power Engineering named after A. I. Leypunsky")

Presentation materials