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THE
ORCBS > Radiation
Safety
> Radiation
Safety Manual
>
 Quantifying
Levels of Radioactivity in Waste
Radioactive and
other hazardous materials must be completely manifested in the waste.
In order to accurately list levels of radioactivity on the tags, it
is necessary to assess the levels which are disposed in both liquid
and solid waste. Suggestions on methods to quantify the waste follow.
- During a
given experiment it is known that a certain quantity of radionuclide
is used. At the end of each of several similar experiments, take
a sample of liquid waste and count it with the appropriate counting
equipment. The activity in the sample per unit volume is then
multiplied by the total volume of the liquid waste generated.
For the solid waste, the quantity of radioactivity in the liquid
is subtracted from the total quantity used in the experiment,
and the remainder is then the quantity in the solid waste.
Example:
| Total
Used in experiment: |
500
uCi |
| Liquid
Sample Volume: |
1 ml |
| Total
Liquid Waste Volume: |
4000
ml |
| Activity
in Liquid Waste Sample: |
8 E-2
uCi/ml |
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| Liquid
Waste Total Activity: |
8 E-2
uCi/ml X 4000 ml. = 320 uCi in liquid waste |
| Solid
Waste Total Activity: |
500
uCi - 320 uCi = 180 uCi in solid waste |
- After the
first few experiments, or when the waste carboy is full, take
a sample of the pooled liquid waste, and count it as above. Multiply
the activity of the sample per unit volume by the total volume
in the carboy to obtain the total activity in the carboy.
Quantify the solid waste as above by subtracting the liquid waste
activity.
General
Rules for Radiation Safety
Radiation
Safety Manual Table of Contents
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