I still think aside from poisoning the world with deadly water the best method would be to treat radiation as an aspect of the reactor that needs to be managed rather than an object to be removed.
Similar to calcification but which causes radiation damage in a radius around reactor parts similar to how bees operate when you are near their hives. The greater the radiation build up in a reactor the stronger and larger that radius becomes.
Therefore a managed reactor is safe while as a poorly maintained or abandoned reactor becomes deadly.
MINI EDIT
(At this point the hazmat suit would be a must for shutting down / repairing the reactor.)
EDIT
Theoretically at this point it could spew contaminated waste or water which could be stored and cleaned or voided, but would not resolve the underlying problem of the unmaintained reactor.