Question

OSHA currently sets an exposure limit of 50 mSv per year for worker exposure to radiation. If an worker at a banana processing plant could be exposed to 150 micro-siverts per hour at a position 1 meter from the storage hopper, how far away from the hopper would a full time worker have to stand during processing to ensure they are not exposed to more than the exposure limit?

Answer 1

So the limit now is set at 50 msv or 50 milli siverts per year

If the worker is assumed to be working n hours a day

And for 365 days he will be exposed to radiation for 365*n hours

That means the limit will be 50msv/(365*n) per hour.

136.986/n micro siverts per hour

These gamma and x rays follow inverse square law

If our current source produces 150 microsv at 1 meter distance then our reqired distance is

So from this if the worker is in the processing plant for 8hours(typical working day) then from the equation the distance is 1.0464√8 that is 2.9596 meter

If he is staying in the plant all the time ie,24 hours

Distance = 1.0464√24=5.1262meters

However there are additional conditions in OSHA RULES that

For occupational exposure, the limit is 50mSv in a single year with a maximum of 100 mSv in a consecutive five-year period.