The UK Atomic Energy Authority signed contracts in the 1980s and 90s to recycle foreign nuclear fuel.
The contracts required customers to take back the radioactive waste as well as the re-usable nuclear material sent to Dounreay for recovery.
The Nuclear Decommissioning Authority inherited the contracts when it took over the site. International Nuclear Services, a subsidiary company of the NDA, is responsible for closure of these contracts.
The consultation announced today seeks views on the substitution of one type of cemented waste with another and the substitution of vitrified waste in place of cemented wastes.