R24x
= 2.2 cGyph
(R1x = 100 cGyph, n = 1.2)
R21y
= 7.4 cGyph
(R1y = 200 cGyph, n = 1.1)
Rtotal
= 9.6 cGyph
Step 3.
Calculate the total dose rate.
Calculate the total dose rate for 0800 hours 48 hours after the first burst by finding the dose rate
for the specific time for each contributor separately; then add the two values. Use Figure 6-5 on
page 6-11.
R48x
= 0.95 cGyph
(R1x = 100 cGyph n = 1.2)
R45y
= 3.15 cGyph
(R1y = 200 cGyph n = 1.1)
Rtotal
= 4.1 cGyph
This method is exact. These values represent the actual values.
(3). Insufficient Information Known to Permit Separation of Different Contributions.
When there is not sufficient known information available about an area of overlapping nuclear
contamination to permit separation of the contribution by each pattern, the following procedure should
be used to determine the rate of decay.
For a specific location, plot on log-log graph paper the latest two dose rate measurements
Step 1.
(after final fallout peak) against time after the latest detonation. This step requires two or
more dose rate measurements at that location after final fallout peak, as well as, a knowledge
of the time of the latest detonation. If the time of the latest detonation is unknown, estimate
H-hour as the time of the latest known burst.
Draw a straight line through these points and extrapolate the line to later times.
Step 2.
Determine a first approximation of the future dose rate directly from the graph.
Step 3.
Plot a later dose rate measurement at that location when it becomes available.
Step 4.
Draw a straight line through the new latest two points and extrapolate the line to later times.
Step 5.
Determine a better approximation of the future dose rate directly from the latest
Step 6.
6-17
CM2308
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