Leach behavior of hydrofracture grout incorporating radioactive wastes

Technical Report · Thu Jan 01 04:00:00 EST 1976

OSTI ID:7364777

Moore, J G; Godbee, H W; Kibbey, A H

Rates at which Sr, Cs, Pu, and Cm are leached from hydrofracture grout were measured. The fraction of an isotope leached varied with the square root of time if the leachant was replaced more frequently than once per day, but was inhibited or depressed if replacement was made less often. The amount of Sr or Cs leached from the grout varied directly with the degree of drying during curing and inversely with the time of curing. Of the clay additives studied for enhancing cesium retention, Grundite, while satisfactory, was the least effective. In general, the isotope leach rate followed the order: Cs greater than Sr greater than Cm greater than Pu. The amount leached as a function of the leachant varied in the order: distilled water greater than tap water greater than grout water. Concentrating the waste by a factor of up to 4 before grouting had little effect on the leach rate. Comparison with results for other products indicates that the grout can provide leach rates comparable to those for wastes incorporated into borosilicate glass. Theoretical relationships that consider diffusion and instantaneous reaction (an equilibrium or time-dependent relationship between mobile and immobile forms of a species) were in good agreement with the data for the 28-day-cured grout when the leachant was initially replaced twice per day. The credibility of laboratory results with simulated waste was substantiated by a short-term continuous leach test made on a fragment of a core sample of actual hydrofracture grout. The modified effective diffusivities (10/sup -11/ to 10/sup -10/ cm/sup 2//s, equivalent to a leach rate of the order of 10/sup -7/ g cm/sup -2/ day/sup -1/) for Sr and Cs calculated from these data are comparable to laboratory values. 17 figures, 5 tables (DLC)

• Research Organization: Oak Ridge National Lab., Tenn. (USA)
• OSTI ID: 7364777
• Report Number(s): TID-27033
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACTINIDES
ALKALI METALS
ALKALINE EARTH METALS
BUILDING MATERIALS
CEMENTS
CESIUM
CLAYS
CURIUM
DISSOLUTION
ELEMENTS
LEACHING
MANAGEMENT
MATERIALS
METALS
MINERALS
PHASE TRANSFORMATIONS
PLUTONIUM
PROCESSING
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE PROCESSING
SEPARATION PROCESSES
SOLIDIFICATION
STRONTIUM
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM ELEMENTS
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTE PROCESSING