2020, Mohemmedi, B., Mehdi, M., Panin, M. P., Pripachkin, D. A., Панин, Михаил Петрович, Припачкин, Дмитрий Александрович

© Published under licence by IOP Publishing Ltd.A three-dimensional Computational Fluid Dynamics (CFD) model is used to simulate the dispersion of radioactive gas from the Chernobyl accident. The most important features of the model are a totally 3-dimensional advection-diffusion equation. Computing the rise of the plume from an accident is an important point for estimating the release of radioactive gas into the atmosphere. The analysis of the plume rise at the time of the Chernobyl accident presents some special circumstances. This is caused by the very high temperature resulting from the burning of graphite. The modeling was performed using Reynolds-Averaged Navier-Stokes RANS method using the k-ϵ model delivered by the commercial code ANSYS-Fluent. The results of the simulation were verified against the measurements taken by aircraft.

2019, Kolodin, E. M., Panin, M. P., Frolov, I. A., Панин, Михаил Петрович

2021, Demin, V. M., Kolodin, E. M., Panin, M. P., Демин, Виктор Максимович, Панин, Михаил Петрович

© 2021, Springer Science+Business Media, LLC, part of Springer Nature.The applicability of a high-pressure xenon based spectrometer for determining the parameters of radioactive contamination of soil or building structures by 137Cs resulting from a radiation accident was studied. For soil contaminated by 137Cs with an exponential depth distribution, the Monte Carlo method was used to calculate the characteristics of the radiation field at the detection height and the instrumental gamma spectra. It is shown that there is promise in using such a detector to determine the parameters of the contamination penetration into the interior volume of the material. It is shown that the sensitivity of the measurement of activity along depth depends on the width of the working zone in the valley and the influence of the thickness of the body of the detector is determined.

2020, Mehdi, M., Panin, M. P., Панин, Михаил Петрович

© 2020 Obninsk Institute for Nuclear Power Engineering, National Research Nuclear University 'MEPhI'. All rights reserved.ANSYS FLUENT tools were used as part of a standard turbulence (k-ε)-model to simulate the air flow around a number of typical obstructions (a 3D cube, a 3D hemisphere, and a 2D hill) which form a potential terrain in the NPP emission spread area and roughly correspond to the geometry of the buildings and structures within this area. For reproducibility, a non-uniform spatial grid is plotted in the computational region which condenses near the obstruction surface and the outer boundaries. The dimensions and the positions of the obstructions were chosen such that to ensure their best possible coincidence with the conditions of the published experiments. The result of modeling the velocity and direction of the air flow as the whole shows a good agreement with the data from the wind tunnel experiments in the areas in front of and over the obstruction, as well as in its aerodynamic shadow. Typical accelerated flow, vortex, and reverse flow areas are reproduced reliably. There are variances observed only in the local heavy turbulence regions in the obstruction’s aerodynamic shadow near the ground surface. All this indicates that it is possible to model in full scale the spread of the NPP emissions taking into account the features of the plant site terrain and the major onsite structures to determine more accurately the personnel and public exposure dose.

2021, Mehdi, M., Panin, M. P., Панин, Михаил Петрович