Contributions towards the development of a packaging concept for the final disposal of spent HTGR pebble bed fuel

Supplemental Report on Nuclear Safeguards Considerations for the Pebble Bed Modular Reactor (PBMR)

“…Conditioned waste is understood from context but not specifically defined by IAEA to mean "stabilized" in terms of not allowing for or resisting the leakage or leaching of the enclosed nuclear material or similarly resisting access to remove external nuclear material contamination on the surfaces of the enclosed contaminated material. In this sense, the enclosure of coated particles in graphitized carbon or graphite has been recognized by technical experts in both Germany and the United States as sufficiently stabilized for disposal in a repository with no additional steps required beyond canning, with or without an interstitial mix of non-soluble material in the can, where canning is primarily required to facilitate handling of multiple fuel elements [30][31][32][33][34].…”

“…In addition to being a conditioned waste form for the residual LEU, the high content of 232 U and 236 U and the lack of a mature reprocessing technology demonstration make uranium recovery the least attractive option for reuse compared to other spent fuels as discussed in detail in Section 4.3; however, the waste form is judged to be very suitable for direct geologic disposal [30][31][32][33][34]. 6.…”

Management of Radioactive Waste Containing Graphite: Overview of Methods

“…Thus, the resulting parts containing graphite should be grouped based on the emitted radioactivity type and contamination levels. Many countries prefer the method of simple storage of graphite-containing waste packed into properly covered and sealed special casks (called also type B drum packages) [42][43][44][45]. To allow for the safe and long-term isolation of graphite-containing vessels from the environment, they should be filled with special hardening mixtures, which are predominantly polymeric conservation agents [46,47]; however, any filling material used for ordinary radioactive waste may also be applied.…”