Briefly explain why uranium fuel rods in nuclear reactors cannot be used in atomic weapons without further processing.

• A. The uranium fuel rods in nuclear reactors are too hazardous for use in atomic weapons.
• B. The uranium fuel rods in nuclear reactors are too massive and almost impossible to transport during military use.
• C. Without further treatment, uranium fuel rods in nuclear reactors will explode during transportation if used for atomic weapons.
• D. Without further processing, the U-235 enrichment of uranium fuel rods in nuclear reactors is not high enough to be fit for use in atomic weapons.

Answer: (D)