A particular task exposes the operator to alpha radiation at an average dose of 200 ìGy each time the task is performed. If the company needs the task performed once per day over a 250-day working year and the maximum occupational dose limit is 20mSv per year, how many staff does the company need to assign to the task?
To determine how many staff the company needs to assign to the task, we need to calculate the total dose that each staff member will receive and compare it to the maximum occupational dose limit.
First, let's convert the given dose limits to the same unit, which is in this case the sievert (Sv).
1 milliSievert (mSv) = 1000 microSievert (μSv)
So, the maximum occupational dose limit of 20 mSv per year is equal to:
20 mSv = 20,000 μSv
Next, we need to calculate the total dose each staff member would receive if they performed the task once per day over a 250-day working year.
Dose per task = 200 μGy
Number of tasks per year = 250 (days)
Total dose per staff member per year = Dose per task x Number of tasks per year
Total dose per staff member per year = 200 μGy x 250
However, to convert this to microSieverts (μSv) and compare it to the dosage limit, we need to apply a conversion factor known as the dose conversion factor (DCF). The DCF for alpha radiation is typically 20.
Total dose per staff member per year (in μSv) = Dose per task x Number of tasks per year x DCF
Total dose per staff member per year (in μSv) = 200 μGy x 250 x 20
Now we can calculate the total dose a staff member would receive in microSieverts (μSv) per year.
Total dose per staff member per year (in μSv) = 200 μGy x 250 x 20
The calculated value is the dose a single staff member would receive in a year. To determine the number of staff members needed, we divide the maximum allowable dose by the calculated total dose per staff member per year.
Number of staff members needed = Maximum allowable dose / Total dose per staff member per year (in μSv)
Number of staff members needed = 20,000 μSv / (200 μGy x 250 x 20)
Now, we can perform the calculation:
Number of staff members needed = 20,000 μSv / (200 μGy x 250 x 20)
Performing the calculation, we find that the number of staff members needed is:
Number of staff members needed ≈ 2.5
Since you cannot have a fraction of a staff member, in this case, you would need to assign 3 staff members to the task to ensure that the maximum allowable dose limit is not exceeded.