Existing Exposure Situation

Radiation protection focus on the protection of humans and for this purpose, three basic categories of exposure have been considered namely...

• Occupational exposure

• Medical exposure

• Public exposure

• Mild exposure

The terms “planned”, “emergency” and “exiting” refer to the ________, not the EXPOSURE !

• Temperature

• Humidity

• Situation

• Explaination

Answer explanation

The terms “planned”, “emergency” and “existing” refer to the SITUATION, not the EXPOSURE !

List down three types of exposure situations in defining the relevant radiation protection requirements..

• Planned exposure situation

• Routine exposure situation

• Emergency exposure situation

• Existing exposure situation

Existing exposure situation is...

• situation of exposure to emergency exposure

• situation of exposure that already exist when a decision on the need for control needs to be taken

• situation of exposure to natural background radiation

• exposure due to residual radioactive material that derives from past practices that were not subject to regulatory control

Those are the examples of most excluded exposures which unamenable to control under existing exposure situations, EXCEPT:

• Exposure to ⁴⁰K in body

• Exposure to cosmic radiation at the earth's surface

• Occupational exposure to cosmic in commercial aircraft

• Public exposure to ²²²Rn, ²²⁰Rn and their progeny in the air outdoors

Health effects of concern arising from the existing exposure situations:

• Deterministic effects

• Stochastic effects

• Deterministic and stochastic effects

• No concern

Answer explanation

Doses will be well below the threshold for deterministic effects. Only stochastic effects have to be considered

Exposure to natural sources which subject to the requirements for existing exposure situations:

• Residues from unregulated or poorly regulated past activities

• Everyday commodities regardless of radionuclide concentration such as in food, animal feed, drinking water and construction materials

• Public exposure to outdoor radon

• Occupational exposure to cosmic radiation above Earth’s surface

Answer explanation

Public exposure to indoor radon and not outdoor radon was subjected to requirements for existing exposure situations

Exceptions for materials other than everyday commodities to subject to the requirement for existing exposure situations are:

• U, Th series <1 Bq/g or ⁴⁰K <10 Bq/g

• U, Th series >1 Bq/g or ⁴⁰K >10 Bq/g

• U, Th series >1 Bq/g or ⁴⁰K <10 Bq/g

• U, Th series >1 Bq/g or ⁴⁰K <10 Bq/g

Existing exposure situation to radionuclides of natural origin in occupational exposure treated as a planned exposure situation due to the following exceptions:

• Radon in workplaces where other U, Th series radionuclides are controlled as a limited exposure situation

• Radon in workplaces where where the radon concentration remains below the reference level

• Exposure to radon when concentration cannot be reduced to below the reference level such as underground mining on non-radioactive ore ventilation problems

• Exposure to radon when the U, Th series radionuclides is controlled as planned exposure situation such as underground mining of radioactive ore

Occupational exposure to cosmic radiation above the Earth’s surface subject to the requirements for existing exposure situations EXCEPT for

• Space Crew

• Air Crew

• Pilot of commercial aircraft

• Frequent flyer in commercial aircraft