Which property relates to external surfaces of the packaging?

• A. The dose rate on the external surface must not exceed 0.5 mrem/h
• B. The smallest dimension must be at least 20 cm
• C. External surfaces are easily decontaminated and cannot collect water
• D. The package must be able to withstand immersion for 24 hours

Answer: (C)

External surface properties focus on how the outside of the package behaves regarding contamination. The best match is that external surfaces are easily decontaminated and cannot collect water. This directly describes surface characteristics that affect how contaminants can be removed and how water interaction is prevented, reducing the risk of spreading contamination during handling and transport.

While a surface dose-rate limit exists, it’s a regulatory limit describing allowable radiation at the surface rather than a property of the surface itself. The remaining options relate to size or durability conditions that don’t address how the surface interacts with contamination.