Yes. It's a significant problem for two reasons: 1. High energy particles destroy the container. Alpha particles, which are just Helium nuclei, are quite small

Yes. It's a significant problem for two reasons: 1. High energy particles destroy the container. Alpha particles, which are just Helium nuclei, are quite small and can in between metal atoms. Neutrons too. High energy electrons too; and 2. It's an energy loss for the system to lose particles this way. Magnetic confinement works for alpha and beta particles because they're electrically charged. Neutrons are a far bigger problem, such that you have fun phrases like "neutron embrittlement".