adjective sev·er·al \ˈsev-rəl, ˈse-və-\
2. a : more than one b : more than two but fewer than many; c: (chiefly dialectal) being a great many (Merriam-Webster, 2017)
This is not a dialectical argument, and the use of “several” is a severe understatement and incorrect in this context.
According to the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), in 1962 alone there were 178 nuclear tests, the heaviest year of testing from Trinity (July 16, 1945) to date.
Vague language is not strong language. At best it’s lazy and at worst it’s slippery. You don’t want people thinking that you’re a politician, do you?