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Behavior of technetium in nuclear waste vitrification processes.

Pegg IL - J Radioanal Nucl Chem (2015)

Bottom Line: The tests employed several simulants, spiked with (99m)Tc and Re (a potential surrogate), of the low activity waste separated from nuclear wastes in storage in the Hanford tanks, which is planned for immobilization in borosilicate glass.Single-pass technetium retention averaged about 35 % and increased significantly with recycle of the off-gas treatment fluids.The fraction escaping the recycle loop was very small.

View Article: PubMed Central - PubMed

Affiliation: Vitreous State Laboratory, The Catholic University of America, 620 Michigan Avenue, NE, Washington, DC 20064 USA.

ABSTRACT

Nearly 100 tests were performed with prototypical melters and off-gas system components to investigate the extents to which technetium is incorporated into the glass melt, partitioned to the off-gas stream, and captured by the off-gas treatment system components during waste vitrification. The tests employed several simulants, spiked with (99m)Tc and Re (a potential surrogate), of the low activity waste separated from nuclear wastes in storage in the Hanford tanks, which is planned for immobilization in borosilicate glass. Single-pass technetium retention averaged about 35 % and increased significantly with recycle of the off-gas treatment fluids. The fraction escaping the recycle loop was very small.

No MeSH data available.


Related in: MedlinePlus

Comparison of measured technetium concentration in the glass product with that calculated from a system process model with no adjustable parameters
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Fig4: Comparison of measured technetium concentration in the glass product with that calculated from a system process model with no adjustable parameters

Mentions: Overall, technetium and rhenium showed remarkably similar distribution across the various system sumps. However, as noted above, the retention factor for technetium in the SBS was significantly lower than that for rhenium, both on average and in all but one of the individual tests. The steady state retention of technetium in the glass product showed a reasonable correlation to that for rhenium, with the average rhenium retention being roughly 10 % absolute higher than that for technetium, similar to what was observed in the single-pass tests. The technetium mass balance closure reached as high as 99 % but averaged about 94 %, which is about 8 % lower than that observed for rhenium. When the measured retention factors for technetium and rhenium for each of the system components are input into a process model that was developed for the system, reasonable agreement with measured glass data was found, as shown in Fig. 4 [14, 15].Fig. 4


Behavior of technetium in nuclear waste vitrification processes.

Pegg IL - J Radioanal Nucl Chem (2015)

Comparison of measured technetium concentration in the glass product with that calculated from a system process model with no adjustable parameters
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4514641&req=5

Fig4: Comparison of measured technetium concentration in the glass product with that calculated from a system process model with no adjustable parameters
Mentions: Overall, technetium and rhenium showed remarkably similar distribution across the various system sumps. However, as noted above, the retention factor for technetium in the SBS was significantly lower than that for rhenium, both on average and in all but one of the individual tests. The steady state retention of technetium in the glass product showed a reasonable correlation to that for rhenium, with the average rhenium retention being roughly 10 % absolute higher than that for technetium, similar to what was observed in the single-pass tests. The technetium mass balance closure reached as high as 99 % but averaged about 94 %, which is about 8 % lower than that observed for rhenium. When the measured retention factors for technetium and rhenium for each of the system components are input into a process model that was developed for the system, reasonable agreement with measured glass data was found, as shown in Fig. 4 [14, 15].Fig. 4

Bottom Line: The tests employed several simulants, spiked with (99m)Tc and Re (a potential surrogate), of the low activity waste separated from nuclear wastes in storage in the Hanford tanks, which is planned for immobilization in borosilicate glass.Single-pass technetium retention averaged about 35 % and increased significantly with recycle of the off-gas treatment fluids.The fraction escaping the recycle loop was very small.

View Article: PubMed Central - PubMed

Affiliation: Vitreous State Laboratory, The Catholic University of America, 620 Michigan Avenue, NE, Washington, DC 20064 USA.

ABSTRACT

Nearly 100 tests were performed with prototypical melters and off-gas system components to investigate the extents to which technetium is incorporated into the glass melt, partitioned to the off-gas stream, and captured by the off-gas treatment system components during waste vitrification. The tests employed several simulants, spiked with (99m)Tc and Re (a potential surrogate), of the low activity waste separated from nuclear wastes in storage in the Hanford tanks, which is planned for immobilization in borosilicate glass. Single-pass technetium retention averaged about 35 % and increased significantly with recycle of the off-gas treatment fluids. The fraction escaping the recycle loop was very small.

No MeSH data available.


Related in: MedlinePlus