Degradation of Saltstone Disposal Unit Cementitious Materials
- Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
The Saltstone facilities at the DOE Savannah River Site (SRS) are used to stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of a saltstone disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation-influenced steel corrosion, and decalcification (primary constituent leaching) as the chemical degradation phenomena of most significance under SRS exposure conditions.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC09-08SR22470
- OSTI ID:
- 1513682
- Report Number(s):
- SRNL-STI-2018-00077
- Country of Publication:
- United States
- Language:
- English
Similar Records
Degradation of cementitious materials associated with salstone disposal units
VARIABILITY OF KD VALUES IN CEMENTITIOUS MATERIALS AND SEDIMENTS