Exercise #15

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• Problem #1 - In the previous dose calculation, we used a pre‐defined file with the emission rates and dose conversion factors for the top-ten radionuclides. Which one of these radionuclides is the most important for air dose and deposition dose?

• Hint - Simply multiply the emission rate and dose conversion factors to determine the contribution of each radionuclide.

• Solution - Importing the activity.txt file into EXCEL to compute the products, shows that 133Xe was the largest contributor to the air dose, but 133I was the largest contributor to the deposition dose. Would the top-ten list be the same after one week or one year?

• Problem #2 - In the previous dose calculation, we used a 5 km resolution concentration grid. Would the dose still be under-estimated if we used a finer concentration grid?

• Hint - Edit and run the cust_dose batch file to use a 1 km by 250 m grid resolution.

• Solution - 5 km air dose versus 1 km air dose
and 5 km deposition dose versus 1 km deposition dose.
• 6 m 1 s

• Problem #3 - There is some uncertainty regarding particle sizes for this event and a fraction of the radionuclides may have been emitted on much larger particles. Using the same configuration as in problem #1, recompute the doses using a deposition velocity of 1 cm/s rather than 0.1 cm/s.

• Hint - Edit the script cust_dose and rerun the calculation.

• Solution - Although the air dose is unchanged, the maximum deposition dose has more than almost doubled.
• 5 m 54 s