Case Studies: Full-Scale Operations and Delivery Systems - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 363

TABLE 13.10
SRS High-Level Waste Tank Fill Formulations Used for Tank 17-F and 20-F
Closure

SRS Reducing Grout
Encapsulate
Incidental Waste

SRS Zero-Bleed
Flowable Fill
Bulk Tank Fill

SRS Zero-Bleed
2000 psi Grout
Intruder Barrier Application

Portland cement Type I (lbs/cyd) 1353 150 550

Slag, Grade 100 (lbs/cyd) 209 - -

Fly ash, Class F (lbs/cyd) - 500 -

Silica fume (lbs/cyd) 90 - -

Quartz sand ASTM C-33 (lbs/cyd) 1625 2300 2285

Water (gal/cyd) 86.4 63 65

HRWR* (fl.oz/cyd) 250 - -

Retarder (fl.oz/cyd) 150 - -

Sodium Thiosulfate** (lbs/cyd) 2.1 - -

Advaflow*** (HRWR) (fl.oz/cyd) - 90 140

Welan Gum Kelco-crete*** (grams/cyd) - 275 275

* High range water reducer.
**Added to the mix as a liquid solution.
***Premixed and metered into the auger as a suspension.

into a concrete pump that transferred grout about 2000 ft through a 5-in. steel line.
Grout production for each plant was targeted at 40 yd 3 per hour (80 yd 3 per hour
total). All three grouts were designed to be flowable and self-leveling as shown in
Figure 13.16 (seen as discharged from the mixer).
The first grout placed in each tank was designed to stabilize the contaminants
in the residual heel that could not be removed by remote means. The heel consisted
of a few thousand gallons of sludge up to 5 cm deep on the tank bottom. This first
layer is referred to as a reducing grout because it contains reagents to chemically
reduce certain contaminants of concern, 99 Tc and Cr +6 , to lower valence states
resulting in precipitates in alkaline conditions. Controlled Low Strength Material
(CLSM) was used as bulk fill for most of the tank volume. A strong grout was added
to the top of the tank and served as an intruder barrier. The ingredients and propor-
tions in the SRS tank fill materials are listed in Table 13.10.

REFERENCES

1. Conner, J.R. Chemical fixation and solidification of hazardous wastes , New York:

Van Nostrand Reinhold, 1990.

2. O'Hara, M.J. Immobilization of lead and cadmium in solid residues from the com-

bustion of refuse using lime and phosphate. U.S. Patent 4,737,356, 1988.

3. Multi-Point Injection Demonstration for Solidification of Shallow Buried Waste at

Oak Ridge Reservation, Oak Ridge, TN, ORNL/ER-378, prepared by Ground Envi-
ronmental Services, Inc., October 1996.