Which device is used to secure a nuclear gauge for transport to prevent unauthorized access?

The tamper-evident seal is a critical tool used to enhance the security of a nuclear gauge during transport, ensuring that it remains protected from unauthorized access. This seal serves as a visible indicator of whether the gauge has been tampered with or accessed in an unauthorized manner. If the seal is broken or shows signs of tampering, it alerts personnel to a potential security breach, thereby safeguarding sensitive radioactive materials.

While other options can contribute to the overall physical security of the gauge, they do not provide the same level of protection against unauthorized access and tampering. For instance, a padlock may prevent casual access but does not provide a clear indication of tampering. Similarly, a plastic strap or safety latch may help secure the gauge physically but lacks the specific functionality of signaling unauthorized alteration or access. The tamper-evident seal serves a unique role in promoting accountability and security, making it the best choice for this context.