Vessels can be flushed with clean salt and leaks can be washed with clean salt remotely. ORNL, the laboratory that invented MSR also operated Aqueous homogeneous breeders which leaked a lot. They cleaned the liquid-fuel mess without large exposures. Cleaning is easy because fuel is a liquid. It flows. It is in a form that can be diluted easily. It is not like the melted solid oxide fuel which can't be diluted easily. Gammas pass through mirrors and only visible light gets reflected. Replacing empty pipes, heat exchangers and reactor itself should not be difficult for a industry that routinely replaces highly radioactive and heavy solid "spent" fuel using cranes. MSRE had no leaks and we know that Hastelloy-N works well for up to 5 years. The same Hastelloy-N at lower operating temperatures may last for 10-15 years. All components that work at high temperature needs replacement. Even jet engine blades are replaced every 4-5 years (after something like 15000 hours).