NRRPT Decontamination & Exposure Prevention 2 — Questions and Answers
Question 1: Which of the following best describes 'fixed' contamination?
- Contamination that cannot be detected with standard instruments
- Contamination that is bonded to a surface and cannot be removed by wiping (Correct answer)
- Contamination that has been sealed under a layer of paint or coating
- Contamination located in a fixed, permanently monitored area
Correct answer: Contamination that is bonded to a surface and cannot be removed by wiping
Fixed contamination is radioactive material that is bonded to a surface and cannot be removed by wiping or normal cleaning methods.
Question 2: A worker exits a radiological area and a frisker indicates contamination on their right hand. What is the FIRST action to take?
- Immediately shower with soap and water
- Prevent the worker from leaving the buffer zone and begin decontamination (Correct answer)
- Notify the NRC and document the event
- Apply a skin dose badge and allow the worker to leave
Correct answer: Prevent the worker from leaving the buffer zone and begin decontamination
The worker should be prevented from spreading contamination beyond the buffer zone and decontamination should begin immediately.
Question 3: What is the primary purpose of a 'step-off pad' at a radiological boundary?
- To absorb alpha radiation before workers exit
- To provide a clean surface for removing protective footwear and preventing contamination spread (Correct answer)
- To shield workers from direct radiation shine
- To collect air samples near the boundary
Correct answer: To provide a clean surface for removing protective footwear and preventing contamination spread
Step-off pads provide a clean zone where workers can remove contaminated shoe covers without tracking contamination into clean areas.
Question 4: Which decontamination technique is preferred for skin contamination to avoid damaging the skin's protective barrier?
- Vigorous scrubbing with industrial abrasive cleaners
- Mild soap and lukewarm water with gentle washing (Correct answer)
- Bleach solution diluted to 10%
- Acetone or organic solvent wipes
Correct answer: Mild soap and lukewarm water with gentle washing
Mild soap and lukewarm water with gentle washing is preferred because aggressive scrubbing can break the skin barrier and increase absorption.
Question 5: When performing a smear (swipe) survey to assess removable contamination, what area is typically wiped per smear?
- 1 square centimeter
- 10 square centimeters
- 100 square centimeters (Correct answer)
- 1 square meter
Correct answer: 100 square centimeters
The standard smear survey covers 100 cm² (approximately a 10 cm × 10 cm area) to provide a consistent and reproducible contamination sample.
Question 6: Personnel dosimetry (TLD/OSL badge) primarily protects workers by:
- Alarming when dose rate exceeds safe limits
- Providing a legal record of occupational dose for regulatory compliance and dose tracking (Correct answer)
- Blocking radiation from reaching the body
- Measuring internal dose from ingested radionuclides
Correct answer: Providing a legal record of occupational dose for regulatory compliance and dose tracking
Passive dosimeters record cumulative dose for regulatory compliance, dose tracking, and ensuring workers stay within annual limits — they do not provide real-time alarms.
Question 7: What does the acronym 'ALARA' stand for and what principle does it represent?
- All Levels Are Routinely Assessed — periodic dose auditing
- As Low As Reasonably Achievable — minimizing dose using practicable means (Correct answer)
- Authorized Limit And Radiation Allowance — regulatory dose caps
- Annual Limit on Radiation Activity — source term control
Correct answer: As Low As Reasonably Achievable — minimizing dose using practicable means
ALARA stands for As Low As Reasonably Achievable and requires reducing radiation exposure using time, distance, and shielding whenever practicable.
NRRPT Decontamination & Exposure Prevention 2
Which of the following best describes 'fixed' contamination?