Query: What is a Broken Arrow incident in nuclear security? 
Context: The Air Force, in conjunction with other entities within the Departments of Defense or Energy, achieves a high standard of protection through a stringent nuclear surety program. This program applies to materiel, personnel, and procedures that contribute to the safety, security, and control of nuclear weapons, thus assuring no nuclear accidents, incidents, loss, or unauthorized or accidental use (a Broken Arrow incident). The Air Force continues to pursue safe, secure and effective nuclear weapons consistent with operational requirements.