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Published: 2024-09-23
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DOI: https://doi.org/10.53747/nst.v14i2.418
Issue
Vol. 14 No. 2 (2024)
Section
Articles
How to Cite
Chizhov, K., & Kryuchkov, V. (2024). Unfolding method for surface activity density map reconstruction from ambient dose equivalent rate measurements based on solution of Fredholm equation of the 1st kind. Nuclear Science and Technology, 14(2), 11-15. https://doi.org/10.53747/nst.v14i2.418

Unfolding method for surface activity density map reconstruction from ambient dose equivalent rate measurements based on solution of Fredholm equation of the 1st kind

Konstantin Chizhov1, Victor Kryuchkov2
1 s:4:"JINR";
2 State Research Center—Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency

Main Article Content

Abstract

A mathematical method has been developed for determining surface activity density maps from ambient dose equivalent rate measurements on a site with buildings, taking into account the shielding effect of the buildings by using a visibility matrix. The relationship between surface activity density and ambient dose equivalent rate is described through the Fredholm equation of the 1st kind and is numerically solved with a Tikhonov regularization. Use of the visibility matrix and raster cells made it possible to solve the Fredholm equations in barrier geometry to restore the density of the surface radionuclide contamination based on the ADER measurement. Method was used to restore locations of contamination with 137Cs and its activities for the Andreeva Bay nuclear legacy site. The proposed method can be applied in the process of decontamination of radioactively contaminated territories, in particular during the remediation of the Andreeva Bay.

Article Details

Keywords

Fredholm equation, radionuclide surface contamination, nuclear legacy site

References

[1]. K. Chizhov et al, “Radiation situation dynamics at the Andreeva Bay site for temporary storage of spent nuclear fuel and radioactive waste over the period 2002–2016”, J. Radiol. Prot., 38, 480–509, 2018.
[2]. K. Chizhov et al, “The development and application of a method for assessing radionuclide surface contamination density based on measurements of ambient dose equivalent rate”, J. Radiol. Prot., 39, 354–372, 2019.
[3]. Federal Center for Hygiene and Epidemiology of Rospotrebnadzor, Methodical regulations MU 2.6.1.2153-06 Operative estimation of the population radiation doses caused by the radioactive contamination of the territory from air, ISBN 5-7508-0686-3, Moscow, 2007.
[4]. I. Szőke et al, “Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments”, J. Radiol. Prot., 34.2, 389, 2014).
[5]. K. Saito et al, “Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident”, Journal of environmental radioactivity, 139, 308-319, 2015.
[6]. M. Ninkovic, F. Adrović, Air Kerma Rate Constants for Nuclides Important to Gamma Ray Dosimetry and Practical Application, 10.5772/39170, 2012.
[7]. K. Saito et al, “Effective dose conversion coefficients for radionuclides exponentially distributed in the ground”, Radiation and environmental biophysics, 51, 411-423, 2012.
[8]. V. Mashkovich, A. Kudryavtseva, Protection from ionizing radiation, Moscow: Energoatomizdat, 1995.
[9]. P. C. Hansen, “Numerical tools for analysis and solution of Fredholm integral equations of the first kind”, Inverseproblems, 8, 6, 849, 1992.
[10]. A. Tikhonov, “On incorrect problems of linear algebra and a stable method for their solution”, DAN USSR, 163, 3, 1965.
[11]. A. Vatulyan, O. Yavruyan, Methodical instructions to practical assignments for the course "Inverse problems of mechanics" for students of the Faculty of Mechanics and Mathematics, Rostov-on-Don: Rostov State University, 2005.