Processes for the control of /sup 14/CO/sub 2/ during reprocessing

Notz, K.J.; Holladay, D.W.; Forsberg, C.W.; Haag, G.

doi:10.2172/6681409

Cited by 1 publication

(4 citation statements)

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“…Limited studies have been carried out with alkaline earth hydroxide slurries in stirred tank reactors to absorb CO 2 (Notz 1980). The DF for Ba(OH) 2 ⋅8H 2 O is about 10 times greater than that for Ca(OH) 2 , which is about 10 times greater than that for Mg(OH) 2 .…”

Section: Caustic Slurry Scrubbingmentioning

confidence: 99%

“…Molecular sieves can be used to separate Kr (Lenard-Jones [L-J] kinetic diameter 0.364 nm (Breck 1974)) and CO 2 (L-J kinetic diameter 0.33 nm) from one another (Notz 1980). Zeolites 3A, 4A, and 5A have been studied for off-gas treatment.…”

Section: Molecular Sieve Adsorptionmentioning

confidence: 99%

“…Sorption tests conducted at ORNL with thermal gravimetric analyses indicated, within experimental error, no effect on the sorption of water from a gas stream containing up to 2% V/V CO 2 [unpublished data]. The use of 5A molecular sieves could be coupled with a Kr recovery process or used to effect a Kr from CO 2 separation with a frontal analysis gas-phase chromatographic technique (Notz 1980). The 4A molecular sieve adsorbs Kr at high pressures and moderate temperatures (Brown et al 1976), but when operated at 100 to 300 kPa and 0°C, the adsorption rate is near zero.…”

Section: Molecular Sieve Adsorptionmentioning

confidence: 99%

“…Acceptable performance depends on the final repository situation. This process would eliminate the need for handling liquid streams and separating solids from liquids (Notz 1980). Final reactant conversions greater than 99% are also possible.…”

Section: Adsorbent Bed Fixationmentioning

confidence: 99%

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Assessments and Options for Removal and Immobilization of Volatile Radionuclides from the Processing of Used Nuclear Fuel

Jubin

Strachan

2015

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Nuclear fuel reprocessing is being considered in the US as part of an effort to help meet the nation's energy needs. Various options are available to meet these needs (DOE 2010). The recent Fuel Options Study indicated that fuel cycles that utilize continuous recycling are among the "most promising" (Wigeland et al. 2014). After the valuable components have been extracted from the irradiated UO 2 during reprocessing, the remaining waste must be immobilized and sent to a repository. Some of the radionuclides in the fuel are short-lived isotopes that decay to innocuous levels soon after reactor discharge, e.g., 127 Xe (t 1/2 = 36.4 d). However, the preponderance of radionuclides requires long-term, geological storage. In this report, we assess options for capturing and immobilizing radionuclides expected to volatilize during aqueous reprocessing of used nuclear fuel. This document is an update to a previous report prepared in 2011 that was only released as a draft (FCR&D-SWF-2011-000305). Several radionuclides that require intermediate-to long-term storage become volatile during the processing of the fuel. These include 3 H, 14 C, 85 Kr, and 129 I. These radionuclides are released into the gas streams associated with processing the nuclear fuel and are particularly difficult to remove because of their chemical state and very low concentrations. The SCALE code version 6.0 (ORNL 2009) was used to calculate the masses and activities of these volatile radionuclides in representative used commercial light water reactor (LWR) fuels that could be reprocessed for recycling. Two levels of fuel burnup, 30 GWd/tIHM (gigawatt-days per metric ton initial heavy metal) and 60 GWd/tIHM with 5-and 30-year cooling periods (time out of reactor) were selected as reference cases for the these SCALE calculations. A number of the capture methods are reviewed in this study. Although many appear promising, significant research and development remains to be completed to advance them from the laboratory or bench scale to a level suitable for use in commercial facilities. Likewise, significant development and performance testing is needed for waste forms, particularly for iodine. Assessments and Options for Removal and Immobilization of Volatile Radionuclides from the Processing of Used Nuclear Fuel iv 3/31/15 ACKNOWLEDGMENTS The primary authors of this report wish to acknowledge the many researchers at the DOE national laboratories who are part of the Off-Gas Sigma Team and who have contributed information in support of his study. This includes S.

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Section: Caustic Slurry Scrubbingmentioning

confidence: 99%

Section: Molecular Sieve Adsorptionmentioning

confidence: 99%

Section: Molecular Sieve Adsorptionmentioning

confidence: 99%

Section: Adsorbent Bed Fixationmentioning

confidence: 99%

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