nuclear club vs accumulation

nuclear club and accumulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
nuclear club	Yes	No	No	No
accumulation	Yes	No	No	No

As nouns, accumulation is a hypernym of nuclear club; that is, accumulation is a word with a broader meaning than nuclear club:

Other hypernyms of nuclear club include aggregation, assemblage, collection.

nuclear club (noun)	accumulation (noun)
the nations possessing nuclear weapons	the act of accumulating
	several things grouped together or considered as a whole
	(finance) profits that are not paid out as dividends but are added to the capital base of the corporation
	an increase by natural growth or addition