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- location of the object of economic activity in relation to which the
forecasting and radiation situation estimation done: the distance from object of
economic activity to NPP R , km, the azimuth of the object of economic activity
о
β .
0
The zones of radioactive contamination are formed in the direction of the
surface wind by the average speed of radioactive cloud movement. Average
moving speed of the cloud V aver. depends on the wind speed at a height of 10 m V
10
and categories of stability of the atmosphere (degree of vertical air resistance –
DVAR), which determine according to the table 8.2.

Table 8.2 – Categories of stability of the atmosphere (degree of vertical
air resistance – DVAR)
Wind speed at a Day Night
height of 10 m
(V ), m/sec. Cloudiness Cloudiness
10
No Average Overcast No Overcast

V =2 C C C C C
10

2<V <3 C C IZ IN IN
10
3<V <5 C IZ IZ IZ IN
10
5<V <6 IZ IZ IZ IZ IZ
10

V >6 IZ IZ IZ IZ IZ
10
Note: IN – Inversion, IZ – Isotherm, C – Convection

The dimensions of the zones of the radioactive pollution (length L, km,
width W, km) are determined according to table 8.5, depending on the velocity of
moving the cloud V aver. .
The projected areas of radioactive pollution are mapped to the map (plan) in
the form of ellipses in the direction of the surface wind (Figure 8.2).

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