Which of the following is NOT an example of class 7 radioactive materials?

• A. Nuclear waste
• B. Household batteries
• C. Nuclear fuel rods
• D. Smoke detectors

Answer: (D)

Class 7 covers materials that are radioactive and require special handling and shipping rules. Some items contain tiny amounts of radioactive material but are exempt from Class 7 because the activity is extremely low and the source is sealed.

Nuclear waste and nuclear fuel rods are clearly Class 7 because they emit significant radiation and are produced and handled specifically as radioactive materials, needing strict controls.

Household batteries aren’t inherently radioactive; they store chemical energy, so they aren’t classified as Class 7.

Smoke detectors do contain a very small sealed source of americium-241, but the amount is so low that regulatory frameworks typically exempt these devices from Class 7 transport requirements. That's why the smoke detector is not considered a Class 7 radioactive material in standard classifications.

So, the item that is not an example of Class 7 radioactive materials is the smoke detector.