Sentence:  In the US, the code name for a serious nuclear weapons incident is "<WSD>Broken Arrow</WSD>". It is US policy neither to confirm nor deny the existence of nuclear weapons at any specific location; this also applies to <WSD>Broken Arrow</WSD> incidents. 
Meaning of the word marked with <WSD> tags:  An accidental event that involves nuclear weapons or nuclear components but does not create the risk of nuclear war.<ref>"[https://web.archive.org/web/20120314091212/http://usgovinfo.about.com/library/weekly/aa081600b.htm Wayback Machine Archived link - About.com: US Government info]". Retrieved March 14, 2012</ref><ref>[https://www.osti.gov/biblio/6967497-nuclear-accident-incident-public-affairs-guidance-directive US Department of Defense Directive 5230.16]</ref>