NDT Radiographic Testing Safety 3 — Questions and Answers
Question 1: A film badge (OSL dosimeter) is worn during radiographic testing primarily to:
- Warn the wearer of high radiation in real time
- Measure and record cumulative radiation exposure (Correct answer)
- Shield sensitive body parts from scatter radiation
- Calibrate the radiation source output
Correct answer: Measure and record cumulative radiation exposure
Film badges and OSL dosimeters are passive, legal-record dosimeters that accumulate and record total dose for regulatory compliance.
Question 2: What color is typically used on radiographic exclusion zone barrier ropes or tape to signal a radiation hazard?
- Orange and white
- Blue and white
- Yellow and magenta (or purple) (Correct answer)
- Green and black
Correct answer: Yellow and magenta (or purple)
Yellow and magenta (or purple) are the internationally recognized colors for radiation warning signs and barriers per ANSI/ISO standards.
Question 3: When transporting an Ir-192 camera, which DOT packaging category is most commonly required for a fully loaded industrial radiography camera?
- Excepted Package
- Type A Package
- Type B Package (Correct answer)
- Industrial Package Type 3
Correct answer: Type B Package
The radioactivity levels in a loaded Ir-192 camera typically exceed Type A limits, requiring a DOT-certified Type B package for transport.
Question 4: A pocket dosimeter reads zero at the start of a shift but reads 2 mSv at the end, while the film badge shows only 0.1 mSv. The radiographer should:
- Trust the pocket dosimeter and report 2 mSv
- Trust only the film badge since it is the legal record
- Report both readings and investigate the discrepancy (Correct answer)
- Discard both and estimate dose from source records
Correct answer: Report both readings and investigate the discrepancy
Discrepancies between dosimeters must be investigated and reported to the RSO, as they may indicate dosimeter malfunction or an unreported exposure.
Question 5: A 'restricted area' in radiographic testing is defined as an area where dose could exceed:
- 0.02 mSv (2 mrem) in any one hour
- 0.05 mSv (5 mrem) in any one hour (Correct answer)
- 0.1 mSv (10 mrem) in any one hour
- 1 mSv (100 mrem) in any one hour
Correct answer: 0.05 mSv (5 mrem) in any one hour
Per 10 CFR Part 20, a restricted area is any area where an individual could receive a dose in excess of 0.05 mSv (5 mrem) in any one hour.
Question 6: Which isotope has the longest half-life among those commonly used in industrial radiography?
- Iridium-192 (Ir-192)
- Selenium-75 (Se-75)
- Thulium-170 (Tm-170)
- Cobalt-60 (Co-60) (Correct answer)
Correct answer: Cobalt-60 (Co-60)
Cobalt-60 has a half-life of approximately 5.27 years, significantly longer than Ir-192 (74 days), Se-75 (120 days), or Tm-170 (129 days).
Question 7: If a source becomes stuck in the 'exposed' position during a field radiograph, the FIRST action a radiographer must take is:
- Attempt to manually push the source back with a tool
- Evacuate the immediate area and establish an exclusion zone (Correct answer)
- Call the equipment manufacturer for instructions
- Remove the film cassette to preserve the exposure
Correct answer: Evacuate the immediate area and establish an exclusion zone
Life safety takes precedence: personnel must immediately evacuate and establish an exclusion zone before any other response actions are taken.
NDT Radiographic Testing Safety 3
A film badge (OSL dosimeter) is worn during radiographic testing primarily to: