Description: The radiolytic yields of hydrogen nitrogen, oxygen, nitrous oxide, and carbon monoxide from two batches of WHC-supplied samples of grouted simulated waste have been (gamma) irradiated at several dose rates (0.025, 0.63 and 130 krad/h for hydrogen and 130 krad/h for all other gases). In one batch, the liquid waste simulant that was added to the grout included the original components that were added to Tank 102-AP (labeled "virgin" waste.) The second batch included a similar liquid waste simulant that was preirradiated to 35 Mrad prior to incorporation into the grout. It is believed that the preirradiated samples more closely represent radioactive waste that was stored in the tank for several years. The lowest dose rate corresponds approximately to that expected in the grout; with the high dose rate, doses equivalent to about 85 years storage in grout vaults were achieved. Most of the results on the batch of virgin samples have been reported recently (Report ANL 93/42). Here we report the results from the batch of preirradiated grout samples and compare the results from the two batches. The radiolytic yields of hydrogen and nitrogen are lower in the preirradiated than in the virgin grout. On the other hand G(oxygen) is higher in the preirradiated samples: 0.078 vs. 0.026. The yield of nitrous oxide is essentially the same, G(nitrous oxide) = 0.010, in both. The yields measured from both batches are significantly higher than previously reported values. At 90 C similar amounts of hydrogen were generated thermally from both batches of grout, whereas the total amounts of nitrogen and nitrous oxide were larger for the preirradiated than for the virgin grout samples. At lower temperatures the rate of generation was hardly measurable. Mass spectrometric analysis suggests that NO is thermally (but not radiolytically) released from the grout samples.
Date: March 1994
Creator: Jonah, Charles D.; Kapoor, S.; Matheson, Max S.; Mulac, W. A. & Meisel, Dan
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Partner: UNT Libraries Government Documents Department