Assessment of Skin Contamination in Radiation Dose Evaluation Procedures in Incidents: What is the Process?
How is skin contamination assessed during radiation dose evaluation in an incident?
According to Sub-section 3.4 Section I Annex I.9 issued with Circular 08/2022/TT-BKHCN (effective from July 22, 2022), the process for assessing skin contamination during radiation dose evaluation in an incident is as follows:
a) Diagram
b) Explanation
This procedure stipulates the activity for assessing the equivalent dose to the skin due to surface contamination on the skin or clothing.
Step 1: Collect input information
- Information includes the contamination level on skin or clothing.
Step 2: Evaluate the skin equivalent dose for beta contamination
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(9) |
Where:
Hs = Skin equivalent dose (mSv)
Hs,i = Skin equivalent dose due to radioactive isotope i (mSv)
= Average surface contamination level of radioactive isotope i on skin or clothing (kBq/m^2^)
CF8,i = Conversion factor to effective dose for radioactive isotope i
CFb = Shielding reduction factor due to clothing
Te = Exposure time (h)
What is the procedure for evaluating soil contamination during radiation dose assessment in an incident?
In Sub-section 3.5 Section I Annex I.9 issued with Circular 08/2022/TT-BKHCN (effective from July 22, 2022), the procedure for evaluating radioactive dose due to soil contamination during a radiation dose assessment in an incident is prescribed:
a) Diagram
b) Explanation
This procedure stipulates the activity for assessing the radiation dose due to soil contamination after an incident.
Step 1: Collect input information
- Radioactive isotope activity concentration in soil.
- Environmental dose rate.
- Exposure time.
Step 2: Evaluate the effective dose for different periods
Method 1: According to the radioactive isotope activity concentration in soil
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(10) |
Where:
Eext = Effective dose at the period of interest (mSv)
= Activity concentration of radioactive isotope i in soil (kBq/m^2^)
CF4,i = Conversion factor to effective dose for radioactive isotope i
n = Number of radioactive isotopes
Method 2: According to the environmental dose rate
 |
(11) |
Where:
H*g = Measured dose rate at 1m above the ground (mSv/h)
= Activity concentration of radioactive isotope i in soil (kBq/m^2^)
CF3,i = Conversion factor to effective dose for radioactive isotope i with dose rate at 1m distance [(mSv/h)/kBq/m^3^)]
Method 3: According to the activity concentration of labeled radioactive isotopes
 |
(12) |
Where:
= Concentration of label j in sample (kBq/m^2^)
= Activity concentration of labeled radioactive isotope j in soil (kBq/m^2^)
Step 3: Evaluate the effective dose considering shielding factor
 |
(13) |
Where:
= Effective dose considering shielding factor and occupancy factor (mSv)
SF = Shielding reduction factor
OF = Occupancy factor
Respectfully!
