How can unauthorized access to a radioactive source be prevented?

• A. Locked storage, access-controlled areas, monitoring, inventory controls, and prompt reporting of missing sources.
• B. Display signage without locks.
• C. Only relying on employee honesty.
• D. Keeping sources in open unlocked cabinets.

Answer: (A)

Preventing unauthorized access to a radioactive source relies on defense-in-depth measures that physically restrict entry, monitor activity, and ensure rapid detection and response if something goes wrong. Locked storage and access-controlled areas physically prevent many people from getting to the source and ensure only authorized personnel can reach it. Monitoring provides real-time or near-real-time awareness of who enters restricted zones and when, so any suspicious access attempts are detected quickly. Inventory controls keep an up-to-date record of all sources, their locations, and their status, so a missing source is identified promptly and can be investigated without delay. Prompt reporting of missing sources completes the cycle by enabling rapid containment, investigation, and corrective action, which reduces the risk of theft or diversion.

Signage alone does not stop access, as it does not provide a barrier or restrict entry. Relying on employee honesty is not sufficient on its own, since safeguards must be physical and procedural to reduce risk regardless of individual behavior. Keeping sources in open unlocked cabinets would allow immediate access, which defeats the purpose of protective controls.