Tritium extraction

Tritium extracted from soil moisture in the unsaturated zone at various depths below the surface has been used to infer the progress of recharge of underlying aquifers. Studies of recharge in arid and semi arid zones where water moves very slowly in a downward direction have been particularly instructive [20, 32-35]. 

One of the key chemical problems associated with lithium in fusion reactors is extraction of the tritium that has been either generated in or trapped by lithium. A figure of merit for tritium extraction is the blanket tritium inventory. Very large inventories require excessive start-up inventory and are a potentially large radioactive effluent in the event of a catastrophic accident. 

Gettering. The gettering approach to tritium extraction applies to processing of either liquid metals or gas streams... 

The use of lithium in fusion reactor designs has been described with emphasis on materials compatibility, safety, and tritium extraction. Several chemical issues remain unresolved, including ... 

O. Renoult, et al., Sol-gel lithium aluminate ceramics and tritium extraction mechanisms. J. Nucl. Mater. 219, 233-239 (1995). 

Most operators of CANDU reactors have chosen to apply tritium extraction (also known as detritiation) after their reactors have operated for some years, and tritium levels have risen some way toward equilibrium. This is not required for considerations of environmental release but lower levels can simplify reactor maintenance. 

Eor products having relatively low specific activity, such as some compounds labeled with and which are synthesized on the scale of several millimoles, classical organic chemical separation methods may be utilized, including extraction, precipitation, and crystallization. Eor separation of complex mixtures and for products having high specific activity, such as those labeled with tritium, etc, chromatographic methods utilizing paper, thin... 

Samples of Sedan ejecta were collected around the crater lip and along several transects of the ejecta field. A 10-inch diameter hole is dug with a conventional posthole auger at each sampling station. Discrete samples are taken at depths of 6 inches, 1 foot and at 1-foot intervals below that to a depth of 5 or 6 feet. The sample is passed through a 2-mm. sieve and collected into 1-quart wide-mouthed Mason jars. Samples are shipped to the Lawrence Radiation Laboratory (Livermore, Calif.), where aliquots are taken from the jars and lyophilized on a large vacuum manifold. Individual glass traps are utilized on the manifold and extracted water from each ejecta sample is collected separately. The extracted water is assayed for tritium with a model 3375 Packard liquid... 

Sedan crater as determined by Hansen (4) is quite uniform to the depth of explosive emplacement or over 300 feet. The maximum concentrations of tritium in soil water observed on the crater lip at 4 to 5 feet in our samples are in the same range as those reported by Hansen (4) in crater fallback. Figure 7 shows the vertical distribution of tritium in soil water extracted from Sedan crater fallback, according to Hansen (4), and the maximum concentrations found at our four crater lip sites. 

Tritium count/Hydrogen content) of coal extract (Tritium count/Hydrogen content) of phenanthrene... 

A mixture of 1 gram benzene insoluble residue from the extraction of Ireland Mine coal ana 10 ml. 10% aqueous sodium hydroxide solution was sealed in a glass vial and heated at 100°C. for 4 days in a thermostat. After cooling to room temperature the vial was opened, the aqueous solution decanted, distilled over, and analyzed for tritium content. The solid residue was filtered, washed thoroughly with distilled water, dried, and analyzed for tritium. 

If reactions of the above type occur during extraction, one would expect that gradually less hydrogen exchange takes place as the extraction proceeds because the number of reactive groups decreases. This assumption was tested in the last experiment shown in Table V. The coal was heated for 6 hours at 340°C. with nontritiated phenanthrene prior to extraction with tritiated phenanthrene. When this pretreated coal was extracted, the tritium content of the product was only 15.6% as compared with 21.4%, in the nonpretreated product. This decreased tritium content supports the above assumption and agrees with the proposed reaction mechanism. 

Only in the presence of 3,5-epimerase could a significant exchange of tritium be observed. One line of evidence consistent with this interpretation came from the use of a mutant strain E. coli Y-10, incapable of producing 6-deoxyhexose. When extracts of E. coli Y-10 were incubated with TDP-4-keto-6-deoxyglucose-3T, no exchange with the medium was observed. 

Fats, oils, and dairy products digest sample with lipase, extract with hexane. Purify hexane extracts obtained from either extraction technique by silica solid-phase extraction in the sample cleanup mode. The internal standard is phylloquinone 2,3-epoxide (unlabeled for UV detection and tritium labeled for coulometric detection). 

Isotopic dilution techniques were used to determine residual, tritium-labeled gibberellic acid in potatoes, grapes, and various products derived from barley The seeds, the young plants, or the fruit were treated with labeled gibberellic acid and analyzed at the end of the growth period by extraction of the labeled residue in the presence of carrier gibberellic acid, isolation of a pure crystalline specimen, and subsequent assay by liquid scintillation counting ... 

In 1979/1980, Sweet Murphy (1984) made a survey of tritium in pine needle litter in the Savannah River locality. Water and HTO were extracted by freeze-drying, and organically bound T was estimated following combustion of the dried needles. The HTO content of the atmospheric water vapour was also measured. Figure 4.5 shows Sweet Murphy s results converted from pCi per ml of water to TU. All three variables declined approximately in proportion to distance from the plant, as would be expected for long-term releases. By extrapolation, T in atmospheric water vapour would fall to background (about 13 TU -Fig. 4.2) at a distance of 100 km. 

Sponsel and MacMillan (36,25) have illustrated the use of GAs labeled with deuterium and tritium to quantitate GAs and also to follow their metabolism. In one experiment (25) they injected a measured amount of [2H][3h]gA29 (both species labeled at the same position) into immature pea seeds. Some seeds were extracted immediately and others at regular time intervals thereafter so that the metabolism of GA29 could be studied. 

Our binding assays also identified M. brassicae proteins of the OBP-Type 2 class. Several of these proteins from both male and female antennal extracts were observed to bind the four tritium-labeled analogs of Zll-16 Ac, 16 Ac,... 

The tissue distribution of CSPs was examined by amplifying CSP cDNAs from different parts of the M. brassicae body, including legs (unpublished) and female pheromonal glands (Jacquin-Joly et al., 2001), as well as antennae and proboscis. Moreover, proteins extracted from these tissues appeared to bind tritium-labeled pheromone components. Figure 17.4A shows binding of Zll-... 

Beezhold and Stout [68] studied the effect of using mixed standards on the determination of PCBs. Mixtures of Arochlors 1254 and 1260 were used as comparison standards and gas chromatograms of these mixtures were compared with those obtained from a hexane extract of the sample after clean-up on a Florasil column. Polychlorinated biphenyls were separated from DDT and its analogues on a silica gel column activated for 17h and with 2% (w/w) of water added. The extracts were analysed on a silanised glass column packed with 5% DC-200 and 7.5% QF-1 on Gas Chrom Q (80-100 mesh) operated at 195°C with nitrogen as carrier gas (50-60mL min-1) and a tritium detector. 

DDT Light petroleum 5% DC-11 on Chromosorb NAW DMCS Tritium electron capture Petroleum extracted clean up on Florasil [102]... 

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