Solidification of low-level radioactive wastes in masonry cement. [Masonry cement-boric acid waste forms]
Portland cements are widely used as solidification agents for low-level radioactive wastes. However, it is known that boric acid wastes, as generated at pressurized water reactors (PWR's) are difficult to solidify using ordinary portland cements. Waste containing as little as 5 wt % boric acid inhibits the curing of the cement. For this purpose, the suitability of masonry cement was investigated. Masonry cement, in the US consists of 50 wt % slaked lime (CaOH/sub 2/) and 50 wt % of portland type I cement. Addition of boric acid in molar concentrations equal to or less than the molar concentration of the alkali in the cement eliminates any inhibiting effects. Accordingly, 15 wt % boric acid can be satisfactorily incorporated into masonry cement. The suitability of masonry cement for the solidification of sodium sulfate wastes produced at boiling water reactors (BWR's) was also investigated. It was observed that although sodium sulfate - masonry cement waste forms containing as much as 40 wt % Na/sub 2/SO/sub 4/ can be prepared, waste forms with more than 7 wt % sodium sulfate undergo catastrophic failure when exposed to an aqueous environment. It was determined by x-ray diffraction that in the presence of water, the sulfate reacts with hydrated calcium aluminate to form calcium aluminum sulfate hydrate (ettringite). This reaction involves a volume increase resulting in failure of the waste form. Formulation data were identified to maximize volumetric efficiency for the solidification of boric acid and sodium sulfate wastes. Measurement of some of the waste form properties relevant to evaluating the potential for the release of radionuclides to the environment included leachability, compression strengths and chemical interactions between the waste components and masonry cement. 15 refs., 19 figs., 9 tabs.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6338376
- Report Number(s):
- BNL-52074; ON: DE87012305
- Country of Publication:
- United States
- Language:
- English
Similar Records
Properties of radioactive wastes and waste containers. Progress report No. 5, April--June 1977
Solidification of radioactive waste in a cement/lime mixture
Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
360603 -- Materials-- Properties
360604 -- Materials-- Corrosion
Erosion
& Degradation
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BORIC ACID
BORON
BUILDING MATERIALS
BWR TYPE REACTORS
CEMENTS
CESIUM 137
CESIUM ISOTOPES
CHEMICAL COMPOSITION
COBALT 60
COBALT ISOTOPES
COHERENT SCATTERING
COMPARATIVE EVALUATIONS
COMPRESSION STRENGTH
DATA
DAYS LIVING RADIOISOTOPES
DIAGRAMS
DIFFRACTION
DISSOLUTION
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEACHING
LOW-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MATERIALS
MECHANICAL PROPERTIES
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PROCESSING
PWR TYPE REACTORS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE PROCESSING
RADIOACTIVE WASTES
RADIOISOTOPES
REACTORS
SCATTERING
SEMIMETALS
SEPARATION PROCESSES
SODIUM COMPOUNDS
SODIUM SULFATES
SOLIDIFICATION
STRONTIUM 85
STRONTIUM ISOTOPES
SULFATES
SULFUR COMPOUNDS
TIME DEPENDENCE
WASTE FORMS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
WATER
WATER COOLED REACTORS
WATER MODERATED REACTORS
X-RAY DIFFRACTION
YEARS LIVING RADIOISOTOPES