Radiographic Testing Safety Flashcards
7 cards from real NDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Radiographic Testing Safety flashcards as text
What is the purpose of a 'source activity decay chart' kept on an Ir-192 camera?
Answer: To calculate current source activity for proper exposure times
Because Ir-192 decays continuously, the decay chart lets radiographers calculate current activity so they can set correct exposure times and maintain image quality.
Which area classification applies to a location where dose rate could exceed 0.02 mSv (2 mrem) in any one hour but is unrestricted to the public?
Answer: Unrestricted area
An unrestricted area under 10 CFR Part 20 is one where individual doses stay below 0.02 mSv (2 mrem) per hour and access is not controlled for radiation protection.
A 'two-man rule' in radiographic testing requires that:
Answer: At least two qualified individuals must be present during source exposure operations
The two-man rule ensures that at least two qualified radiographers are present during any exposure, providing a safety check and emergency response capability.
Se-75 is preferred over Ir-192 for imaging thin materials primarily because:
Answer: Se-75 emits lower-energy gamma rays that provide better contrast in thin sections
Se-75's lower energy gamma rays (~66–401 keV) are better suited for thin materials and small-diameter pipe welds, providing superior contrast compared to Ir-192.
After completing a radiographic exposure, a radiographer must perform a 'post-exposure survey' to verify:
Answer: The source has returned to its fully shielded position in the camera
A post-exposure survey with a calibrated radiation survey meter confirms the source is fully retracted and dose rates have returned to background levels.
Which of the following is a deterministic (non-stochastic) radiation effect?
Answer: Radiation-induced cataracts from a threshold dose
Radiation-induced cataracts are a deterministic effect: they occur only above a dose threshold (~500 mGy) and their severity increases with dose above that threshold.
Iridium-192 cameras used in field radiography must be surveyed for radiation levels and integrity after each use. This is required under:
Answer: NRC regulations under 10 CFR Part 34
10 CFR Part 34 specifically governs the use of sealed sources in industrial radiography, including required post-exposure surveys and equipment inspections.