List two primary radiological hazards associated with spent nuclear fuel.

List two primary radiological hazards associated with spent nuclear fuel.

• A. External gamma radiation from decay products and significant decay heat requiring sustained cooling.
• B. Neutron emission and criticality risk.
• C. Alpha radiation and radon production.
• D. Ozone generation and noise.

Answer: (A)

The key idea is that spent nuclear fuel remains radiologically hazardous mainly because of two factors that continue after removal from a reactor: external gamma radiation from a large inventory of decay products, and the significant decay heat that must be removed to keep the fuel safely cooled. External gamma radiation comes from many gamma-emitting isotopes produced in fission. These gamma rays travel and expose nearby workers and surroundings if not adequately shielded, so mitigating external dose requires substantial shielding and distance. Decay heat is the thermal energy released as these radionuclides decay. Even after the reactor is shut down, this heat must be continuously removed; without cooling, the fuel cladding could overheat, potentially damaging fuel integrity and storage systems. The other issues listed—neutron emission and the risk of criticality, alpha radiation with radon production, or unrelated effects like ozone generation and noise—are concerns in certain contexts, but they do not represent the dominant radiological hazards of spent fuel in typical handling and storage scenarios.

The key idea is that spent nuclear fuel remains radiologically hazardous mainly because of two factors that continue after removal from a reactor: external gamma radiation from a large inventory of decay products, and the significant decay heat that must be removed to keep the fuel safely cooled.

External gamma radiation comes from many gamma-emitting isotopes produced in fission. These gamma rays travel and expose nearby workers and surroundings if not adequately shielded, so mitigating external dose requires substantial shielding and distance.

Decay heat is the thermal energy released as these radionuclides decay. Even after the reactor is shut down, this heat must be continuously removed; without cooling, the fuel cladding could overheat, potentially damaging fuel integrity and storage systems.

The other issues listed—neutron emission and the risk of criticality, alpha radiation with radon production, or unrelated effects like ozone generation and noise—are concerns in certain contexts, but they do not represent the dominant radiological hazards of spent fuel in typical handling and storage scenarios.