Sentence:  But nowhere in our military services is there a more highly trained, more qualified group of officers than the Navy's nuclear power officers – Navy <WSD>nukes</WSD>. The responsibilities the Navy's 4,300 <WSD>nukes</WSD> have to assume – procuring, testing, operating, and maintaining our nuclear-powered fleet – require a much deeper level of understanding than is necessary in the other services. 
Meaning of the word marked with <WSD> tags:  A person (such as a sailor in a navy or a scientist) who works with nuclear weapons or nuclear power.