Are there people who are engaged in the research and development of nuclear instruments, and will they be exposed to nuclear radiation frequently?

Generally, contact with radioactive sources is required. Of course, it also depends on the frequency, intensity and source type of contact. Generally, the activity of radioactive sources is very low, so frequent contact for a short time is ok. For example, some exempted sources or alpha sources have low activity or weak penetration, so it is ok to touch them (as long as you don't eat them). According to the usual regulations, I haven't seen any problems except my special physique.

Computers and mobile phones are also radioactive. . .