NRRPT Radioactive Material Control 3 — Questions and Answers
Question 1: Under DOT regulations, a Type A quantity of radioactive material is defined as:
- Any quantity requiring a Type B package for transport
- A quantity not exceeding the A1 or A2 value for the radionuclide (Correct answer)
- Material with a specific activity greater than 70 TBq/kg
- Any exempt quantity approved by the NRC
Correct answer: A quantity not exceeding the A1 or A2 value for the radionuclide
Type A quantities are at or below the A1 (special form) or A2 (normal form) values, which represent the maximum allowed in a Type A package.
Question 2: What does the term 'source check' mean in the context of portable radiation survey instrument quality control?
- Replacing the battery before field use
- Verifying instrument response using a known reference source (Correct answer)
- Calibrating the instrument against a NIST-traceable standard in a lab
- Checking that the probe cable is securely connected
Correct answer: Verifying instrument response using a known reference source
A source check confirms that a survey instrument gives a consistent, expected response to a reference source, indicating the instrument is functioning properly.
Question 3: Which action is required when radioactive material is found missing during a routine inventory?
- Document the discrepancy and investigate during the next scheduled review
- Immediately notify the NRC Operations Center if the missing quantity meets reporting thresholds (Correct answer)
- Increase the frequency of future inventories for that isotope
- Transfer all remaining inventory to a secure vault
Correct answer: Immediately notify the NRC Operations Center if the missing quantity meets reporting thresholds
10 CFR 30.50 and 10 CFR 20.2201 require immediate notification to the NRC Operations Center when theft or loss of reportable quantities of licensed material is discovered.
Question 4: A 'hot particle' is particularly hazardous because it:
- Emits high-energy gamma rays that penetrate shielding
- Delivers a highly localized dose to a small area of skin or tissue (Correct answer)
- Travels rapidly through the body and accumulates in the thyroid
- Produces neutron activation of surrounding materials
Correct answer: Delivers a highly localized dose to a small area of skin or tissue
Hot particles deliver an extremely high local dose rate to a microscopic area of skin or tissue, potentially exceeding skin dose limits even when whole-body dose is low.
Question 5: Which engineering control most effectively reduces airborne radioactive contamination during decommissioning activities?
- Increasing the ventilation exhaust rate in the room
- Using local exhaust ventilation with HEPA filtration at the point of generation (Correct answer)
- Posting additional Caution: Radioactive Material signs
- Requiring all workers to wear powered air-purifying respirators
Correct answer: Using local exhaust ventilation with HEPA filtration at the point of generation
Local exhaust ventilation captures contaminants at their source before they disperse, and HEPA filters prevent release into general ventilation.
Question 6: What is the regulatory basis for establishing a Radiological Controlled Area (RCA) boundary?
- Any location where external dose rates exceed 100 mrem/hr
- Areas where dose rates or contamination levels require access control to limit exposure (Correct answer)
- Rooms that contain sealed sources of any activity level
- Locations where airborne radioactivity exceeds 10 DAC
Correct answer: Areas where dose rates or contamination levels require access control to limit exposure
NRC regulations define controlled areas as locations where access must be managed to protect individuals from exceeding dose limits due to radiation or radioactive contamination.
Question 7: When classifying radioactive waste for disposal, the primary factor distinguishing Class A, B, and C low-level radioactive waste (LLW) is:
- Physical form (solid, liquid, gas)
- Concentration of specific radionuclides relative to regulatory limits (Correct answer)
- Total activity in curies regardless of isotope
- Half-life of the predominant radionuclide only
Correct answer: Concentration of specific radionuclides relative to regulatory limits
10 CFR 61 classifies LLW by comparing radionuclide concentrations in the waste against tabulated limits; higher concentrations require more robust disposal methods.
NRRPT Radioactive Material Control 3
Under DOT regulations, a Type A quantity of radioactive material is defined as: