Which incident involving radioactive materials is a cause for immediate reporting?

The correct answer relates to the immediate need for reporting an incident where a unit loses a tritium device. Tritium is a radioactive isotope of hydrogen, and devices containing tritium are used in various applications, including self-luminous exit signs and watches. The loss of such a device presents significant safety risks, as it can lead to exposure to harmful radiation if not properly secured.

Immediate reporting is crucial in this case because it allows for prompt investigations and recovery actions to prevent any potential harm to individuals or the environment. The loss of a radioactive source like a tritium device could lead to uncontrolled exposure or unintended release of radioactive materials, thus triggering regulatory and safety protocols designed to protect public health and safety.

In contrast, routine safety briefs or scheduled inventory activities do not involve incidents that would directly impact safety, and while an X-Ray machine malfunction may warrant reporting and investigation, it does not typically represent an immediate radiological threat comparable to the loss of a radioactive source.