In each nomogram, the R1 scale is at the right.
This scale shows H+1 dose
rates.
The Rt scale is on the left.
This scale shows dose rates at times other
than H + 1.
b. Essential Information.
In working with nomograms, care should be taken to be as consistent as
possible when joining values with the hairline.
Be sure the hairline
intersects the vertical line and the interpolated value (tick mark) as
closely as possible. It is possible to find any one value on the nomogram
if the other three are given, as illustrated in the example problems below.
c. Example Problems.
The following problems are concerned with technique only and do not consider
the impact that these high dose rates might have on operations in the
contaminated area.
Problem 1.
GIVEN:
Rt = 150 cGy/hr at H + 3 hours.
FIND:
R1.
SOLUTION:
Since
the
soil
type
is
not
known,
calculations will be performed on the Soil Type II index
scale (Figure 5-7).
Align the hairline with the 3-hour
tick mark on the Soil Type II index scale and the 150 cGyph
point on the Rt scale.
Read the dose rate as 190
cGyph
at
the
point
of
intersection with the R1 scale.
ANSWER:
190 cGy/hr.
Problem 2.
GIVEN:
R1 = 300 cGyph.
FIND:
Rt at H + 7 hours when the soil composition approximates
Soil Type III.
CM5206
5-26
Previous Page
