Other Binders - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 134

Portland Envirostone

45

39

40

35

30

25

20

14

15

10

4

5

0.4

0

TRU Surrogate TRU Actual

LANL Evaporator Bottom Waste

FIGURE 6.4.2 Comparison of chromium TCLP performance for portland cement and Envi-
rostone.

immobilized, solid waste form. Several hundred drums of solidified TRU organic
waste were generated by OASIS to meet the WIPP-WAC before being discontinued. 25
No cases of free-liquid generation were reported from this waste form. However,
testing at Argonne National Laboratory (ANL)-West, RFETS, and Idaho National
Environmental and Engineering Laboratory (INEEL) showed the OASIS waste form
to exceed the permissible WIPP Waste Acceptance and transportation (TRUPACT-
II) limits for hydrogen and volatile organic gases. 25 These characteristics would later
become a safety problem and posed a logistical problem that impacted the decom-
missioning schedule of RFETS. 25

6.4.4 A DDITIONAL I NSTANCES OF E NVIROSTONE U SE

Envirostone was either investigated for or used in a few other TRU and LLRW
applications. In 1996 Envirostone was examined for its ability to retard the migration
of 237 Np and 99 Tc from the WIPP repository. 26 Envirostone was found to have inad-
equate absorption potential for the task. Concern was also expressed that Envirostone
contained sufficient nutrients to support microbial growth and activity that could
impact radionuclide migration, corrosion, water chemistry, and hydrology. 26 Pres-
ently, Envirostone remains listed in the DOE/WIPP TRUCON Codes as being a
solidification material/absorbent for some TRU wastes. It is listed at LLNL for use
with small amounts of TRU solvents and oil-based liquids and at ANL-East for TRU
organic wastes and aqueous and homogeneous inorganic wastes. 27,28
Three cases were found of Envirostone being used for the stabilization of low-
level Class B or C radioactive waste. The NRC approved its use for 1 year ending
March 3, 1989, for use with a single unidentified waste stream. 29 The other cases
took place at the Richland, WA, and Beatty, NV, commercial low-level radioactive
disposal sites, where Envirostone was used for a few years for Class A, B, and C
LLRW streams. 29,30 The NRC did not officially grant its approval for the use of
Envirostone in these cases, but deferred to approvals granted by each state. By 1991
Envirostone use for Class B and C LLRW had been discontinued due to NRC
prohibition. 15
At the current time, Envirostone use seems to be restricted to Class A LLRW.
In 1997, it was on the approved solidification list for Class A LLRW at four