Aerodynamic diameter and radioactivity distributions of radioactive aerosols from activated metals cutting for nuclear power plant decommissioning

•Radioactive aerosols from activated metal cutting determine internal dose.•Cutting methods are the most critical factor to influence aerosols distributions.•Choosing cutting methods can reduce aerosols by a factor of 500.•Choosing cutting environments can reduce aerosols by a factor of 100.•Worker’s internal exposure of cobalt-60 can be underestimated by a factor of 4.