CHP CHP Radioactive Materials Handling & Waste Management 1 — Questions and Answers
Question 1: Which NRC license type grants a large institution broad authorization to use a wide range of radioactive materials with minimal individual license amendments?
- Specific license — limited scope
- Type A broad scope specific license (Correct answer)
- General license
- Agreement State registration only
Correct answer: Type A broad scope specific license
A Type A broad scope specific license grants large research institutions authorization to use a wide range of radionuclides without amending the license for each new isotope.
Question 2: When handling unsealed radioactive materials, which personal protective measure is most critical for preventing internal contamination?
- Lead apron to reduce external dose
- Dosimetry badge worn on the chest
- Gloves and appropriate respiratory protection (Correct answer)
- Leaded eyeglasses for lens protection
Correct answer: Gloves and appropriate respiratory protection
Gloves prevent skin contamination and absorption, while respiratory protection prevents inhalation — the primary routes for internal contamination with unsealed sources.
Question 3: What is the most appropriate shielding material for high-energy gamma rays emitted by radionuclides such as Co-60?
- Plexiglass (acrylic)
- Aluminum sheeting
- Lead or dense concrete (Correct answer)
- Cardboard and paper
Correct answer: Lead or dense concrete
Lead's high density and atomic number make it highly effective for attenuating gamma rays through photoelectric absorption, Compton scattering, and pair production.
Question 4: The 'two-person rule' (no lone zone) in nuclear security most commonly applies to which type of radioactive material operation?
- Routine laboratory work with exempt quantities
- Operations involving significant quantities of special nuclear material (SNM) (Correct answer)
- Medical X-ray procedures in hospitals
- Low-level waste disposal activities
Correct answer: Operations involving significant quantities of special nuclear material (SNM)
The two-person rule ensures no single individual has unsupervised access to significant quantities of special nuclear materials, providing a security and safety check.
Question 5: What is the primary purpose of a Radiation Use Authorization (RUA) at a research institution licensed under a broad scope license?
- To comply with state environmental reporting requirements
- To document approved procedures, authorized users, quantities, and locations for safe use (Correct answer)
- To authorize purchase orders for radioactive material vendors
- To report radiation incidents to the NRC
Correct answer: To document approved procedures, authorized users, quantities, and locations for safe use
RUAs document approved procedures, authorized users, quantities, and use locations, providing the institutional framework for managing diverse radioactive material use under a broad license.
Question 6: When using high-energy beta emitters like P-32, why is low-density plastic (acrylic/Lucite) preferred over lead for shielding?
- Plastic is less expensive and easier to fabricate
- Lead produces bremsstrahlung X-rays that increase total dose, while plastic minimizes secondary radiation (Correct answer)
- Plastic provides better attenuation of all radiation types
- Lead is not approved by the NRC for beta shielding
Correct answer: Lead produces bremsstrahlung X-rays that increase total dose, while plastic minimizes secondary radiation
High-Z materials like lead increase bremsstrahlung production from high-energy beta particles, so low-Z plastics are preferred to minimize secondary X-ray generation.
CHP CHP Radioactive Materials Handling & Waste Management 1
Which NRC license type grants a large institution broad authorization to use a wide range of radioactive materials with minimal individual license amendments?