PSI - Issue 36

7

Volodymyr Sydorenko et al. / Procedia Structural Integrity 36 (2022) 318–325 Volodymyr Sydorenko, Sergiy Yeremenko, Viola Vambol et al. / Structural Integrity Procedia 00 (2021) 000 – 000

324

mbV

( ) 100

K t =

2

(6)

SatV

1

where K ( t ) – coefficient of the intensity of deflation; t – deflation time; V 1 , V 2 – average and basic (10,5 м  с

– 1 ) wind speed at a height of 0.5 m;

а – width of the receiving part of the dust collector; b – width of the fire; S – area of the fire. m – average weight of a soil layer contaminated with 137Cs after a forest fire, captured by a dust collector during an intense wind. For the deflation intensity factor, graphical dependencies were obtained under various meteorological conditions. Fig. 4 shows the dependence K (t) after a forest fire (x-axis - wind speed, m/s; y-axis - area of 137Cs contamination zone, m 2 ). Three options for categories were considered: D - unstable stratification of the atmosphere, which is typical for sunny summer weather (convection); В - neutral stratification for summer weather with variable cloudiness (isothermy) A - stable stratification of the atmosphere, which is typical for a frosty winter day (inversion).

B (

) isothermy

A (

) inversion

D (

) convection

Y, m 2

Y, m 2

Y, m 2

10 3

10 3

10 3

K( t ) 1

K( t ) 1

K( t ) 1

10 2

10 2

10 2

K( t ) 2

K( t ) 2

K( t ) 2

10

10 10

10

8

8

0

2

4

6

0

8

0

2

4

6

2

4

6

X, m/c

X, m/c

X, m/c

Fig.4. Dependence of the coefficient of intensity of deflation K (t): K (t 1 )> 10; K (t 2 ) <10 - intensity of 137Cs deflation (t / ha year)

5. Conclusion Using the above model for predicting the transfer of radionuclides after a forest fire, as well as experimental data on the rate of deflation rate of RCP and their ratio in the air, it is possible to estimate the amount of radioactive contamination of the atmosphere for certification of work in the process of localizing and eliminating forest fires in accordance with labor safety requirements, certification of work places of rescuers in terms of working conditions and classification of emergency rescue operations by classes of professional radiation risk for the establishment of insurance rates. The results obtained regarding the mathematical modeling of wind erosion require a new analysis in connection with the emergence of issues of protecting the population and territories from secondary radioactive contamination due to forest fires in the ChEZ. Deflation, as an agent of horizontal migration of radionuclides, is acquiring a new, little-studied area of research. Therefore, it would be advisable to create a full-fledged methodology for assessing the deflation of radionuclides for conducting expert assessments of the radiation situation in the territories affected by the RCP as a result of forest fires.