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 primary unit used to measure absorbed radiation dose in tissue?
Answer: Gray (Gy)
The Gray (Gy) measures absorbed dose, defined as one joule of energy absorbed per kilogram of tissue.
Which type of radiation has the greatest penetrating power?
Answer: Gamma rays
Gamma rays are highly penetrating electromagnetic radiation requiring dense shielding materials like lead or concrete.
What does ALARA stand for in radiographic testing safety?
Answer: As Low As Reasonably Achievable
ALARA is the guiding principle that radiation exposure should be kept as low as reasonably achievable through time, distance, and shielding.
A radiographer is setting up an exposure. Doubling the distance from the source reduces the dose rate by approximately:
Answer: 25% of the original
Per the inverse square law, doubling the distance reduces dose rate to one-quarter (25%) of the original value.
Which regulatory body in the US sets occupational radiation dose limits for NDT workers?
Answer: NRC (Nuclear Regulatory Commission)
The NRC sets occupational radiation dose limits under 10 CFR Part 20, which governs the use of radioactive materials in industry.
What is the annual whole-body occupational dose limit for radiation workers in the US?
Answer: 50 mSv (5 rem)
The NRC limits occupational whole-body dose to 50 mSv (5 rem) per year under 10 CFR Part 20.
Which shielding material is most effective per unit thickness for gamma radiation from Ir-192?
Answer: Lead
Lead's high atomic number and density make it the most effective per-unit-thickness shield against gamma radiation from industrial sources like Ir-192.