NRRPT - National Registry of Radiation Protection Technicians Contamination and Airborne Control Questions and Answers

Question 1

A technician performs a wipe survey for removable contamination. The wipe is counted in an instrument with a 35% efficiency for the beta emitter of concern. If the net count rate for the wipe is 700 cpm, what is the removable contamination level in disintegrations per minute (dpm)?

Accepted Answer

2000 dpm

Answer

To convert from counts per minute (cpm) to disintegrations per minute (dpm), the count rate must be divided by the detector's efficiency for the specific radionuclide and geometry being counted. In this case: dpm = cpm / efficiency = 700 cpm / 0.35 = 2000 dpm.

Question 2

According to 10 CFR 20, which of the following conditions requires an area to be posted as an "Airborne Radioactivity Area"?

Accepted Answer

An individual present in the area without respiratory protection could exceed 12 DAC-hours in a week.

Answer

10 CFR 20.1003 defines an "Airborne Radioactivity Area" as a room or area where airborne radioactive materials exist in concentrations that either (1) are in excess of the Derived Air Concentrations (DACs) or (2) are such that an individual could exceed an intake of 0.6 percent of the Annual Limit on Intake (ALI) or 12 DAC-hours in a week.

Question 3

A worker must enter an area with a general airborne concentration of a specific radionuclide measured at 20 DAC. The worker will wear a full-face, air-purifying respirator. What is the effective airborne concentration inside the respirator mask?

Accepted Answer

0.4 DAC

Answer

A full-face air-purifying respirator has an OSHA-mandated Assigned Protection Factor (APF) of 50. The effective concentration inside the mask is the ambient concentration divided by the APF. Therefore, Effective DAC = 20 DAC / 50 = 0.4 DAC.

Question 4

Which of the following describes the primary function of a High-Efficiency Particulate Air (HEPA) filter used in nuclear ventilation systems?

Accepted Answer

To remove at least 99.97% of airborne particles with a size of 0.3 micrometers.

Answer

The standard definition of a HEPA filter is one that is certified to remove at least 99.97% of airborne particles that are 0.3 micrometers (µm) in diameter. This particle size is considered the most penetrating. HEPA filters are designed for particulates and are not effective for removing radioactive gases.

Question 5

During a routine survey, a worker is found to have a small spot of removable radioactive contamination on their forearm. What is the most appropriate initial action?

Accepted Answer

Gently wash the affected area with mild soap and lukewarm water.

Answer

Standard procedure for personnel decontamination is to begin with the least aggressive method first. Gentle washing with mild soap and lukewarm water is effective at removing loose contamination without abrading or damaging the skin, which could lead to an intake or prevent further, more aggressive decontamination if needed.

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

NRRPT - National Registry of Radiation Protection Technicians Contamination and Airborne Control Questions and Answers