NRRPT Contamination and Airborne Control 4

Question 1

Which particle size range is considered most hazardous for lung deposition from inhaled radioactive aerosols?

Accepted Answer

1–5 micrometers (AMAD)

Answer

Particles in the 1–5 µm AMAD range penetrate into the pulmonary (alveolar) region of the lung where clearance is slowest and dose is highest.

Question 2

A High Efficiency Particulate Air (HEPA) filter is rated to remove what minimum percentage of 0.3-micron particles?

Accepted Answer

99.97%

Answer

HEPA filters must remove at least 99.97% of particles at the most penetrating particle size of 0.3 µm per standard definitions (DOE/NRC requirements).

Question 3

What is the purpose of conducting a 'low-volume grab sample' for airborne radioactivity?

Accepted Answer

Obtain a short-duration air sample to characterize airborne concentrations quickly during a specific task

Answer

Grab samples collect air over a short period to characterize concentrations during a specific work evolution, providing rapid task-specific data.

Question 4

When using HEPA vacuums to clean up dry radioactive contamination, which practice is critical to prevent re-suspension?

Accepted Answer

Pre-wet the surface with a fixative or water mist before vacuuming

Answer

Pre-wetting or applying a fixative binds loose particles to the surface, reducing re-suspension during the vacuuming process.

Question 5

What does a DAC-hour represent in radiation protection practice?

Accepted Answer

The product of airborne concentration in DAC units and the time in hours of exposure

Answer

A DAC-hour is the product of the airborne concentration (expressed as a fraction of DAC) and the time in hours, used to track cumulative internal dose potential.

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

NRRPT Contamination and Airborne Control 4