Immersion and Leach Tests on Solidified Decontamination Wastes from Dresden Unit 1

Abstract

In order to provide technical support to the NRC, Brookhaven National Laboratory has performed leach tests and immersion tests using organic liquids and organic saturated water of concentrated decontamination waste solidified using a vinyl ester-styrene binder.

The leach tests measured the release of Fe, Ni, and Co from these forms in deionized water, groundwater, and seawater. After 64 days, the mean fraction released normalized by V/S for iron was 5.1 ± 1.9 × 10⁻³ cm in deionized water, 7.1 ± 1.1 × 10⁻³ cm in groundwater, and 9.0 ± 3.2 × 10⁻³ cm in seawater. For nickel, 64 day release rates observed were 4.6 ± 1.6 × 10⁻³ cm, 4.6 ± 1.0 × 10⁻³ cm, and 5.9 ± 0.6 × 10⁻³ cm in deionized water, groundwater, and seawater, respectively. After 50 days, the ⁵⁹Fe release rates were 5.9 ± 0.7 × 10⁻³, 4.8 ± 2.4 × 10⁻³, and 2.8 ± 1.0 × 10⁻³ cm in deionized water, groundwater, and seawater, respectively. For ⁶⁰Co, the 50 day releases in the three respective leaching media were 6.0 ± 1.7 × 10⁻³ cm, 6.8 ± 1.0 × 10⁻³ cm, and 2.3 ± 0.2 × 10⁻³ cm.

Immersion tests of waste forms prepared at a solidification demonstration held at the Dresden Nuclear Power Station were conducted in toluene, xylene, and water saturated with toluene and xylene. During immersion of samples in the pure organics, large changes in sample volume and weight were observed. Total weight changes of 9.6 ± 0.3% and 21.6 ± 0.7% were observed after 839 hours of immersion in xylene and toluene, respectively. Air drying of the samples led to an overall weight loss of 23.5 ± 0.7% for xylene and 35.6 ± 0.6% for toluene. Qualitatively, similar changes were observed for immersion tests using organic saturated water. Severe sample deterioration was observed in this case, however. The cause of this deterioration is not known.