Graphite matrix materials for nuclear waste isolation

Technical Report · Mon Jun 01 00:00:00 EDT 1981

DOI:https://doi.org/10.2172/6468330· OSTI ID:6468330

Morgan, W C

At low temperatures, graphites are chemically inert to all but the strongest oxidizing agents. The raw materials from which artificial graphites are produced are plentiful and inexpensive. Morover, the physical properties of artificial graphites can be varied over a very wide range by the choice of raw materials and manufacturing processes. Manufacturing processes are reviewed herein, with primary emphasis on those processes which might be used to produce a graphite matrix for the waste forms. The approach, recommended herein, involves the low-temperature compaction of a finely ground powder produced from graphitized petroleum coke. The resultant compacts should have fairly good strength, low permeability to both liquids and gases, and anisotropic physical properties. In particular, the anisotropy of the thermal expansion coefficients and the thermal conductivity should be advantageous for this application. With two possible exceptions, the graphite matrix appears to be superior to the metal alloy matrices which have been recommended in prior studies. The two possible exceptions are the requirements on strength and permeability; both requirements will be strongly influenced by the containment design, including the choice of materials and the waste form, of the multibarrier package. Various methods for increasing the strength, and for decreasing the permeability of the matrix, are reviewed and discussed in the sections in Incorporation of Other Materials and Elimination of Porosity. However, it would be premature to recommend a particular process until the overall multi-barrier design is better defined. It is recommended that increased emphasis be placed on further development of the low-temperature compacted graphite matrix concept.

• Research Organization: Battelle Pacific Northwest Labs., Richland, WA (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6468330
• Report Number(s): PNL-3556; ON: DE81026322; TRN: 81-012014
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
GRAPHITE
COMPACTING
PERMEABILITY
POROSITY
THERMAL CONDUCTIVITY
THERMAL EXPANSION
RADIOACTIVE WASTE DISPOSAL
ENGINEERED SAFETY SYSTEMS
HIGH-LEVEL RADIOACTIVE WASTES
MATRIX MATERIALS
SOLID WASTES
BACKFILLING
COKE
MANUFACTURING
CARBON
ELEMENTS
EXPANSION
MANAGEMENT
MATERIALS
NONMETALS
PHYSICAL PROPERTIES
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
THERMODYNAMIC PROPERTIES
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052002* - Nuclear Fuels- Waste Disposal & Storage
360603 - Materials- Properties